JP2016215723A - Work vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a work vehicle capable of assisting power of an engine timely with a simple configuration.SOLUTION: A work vehicle equipped with an engine E, with a work unit being attached, includes a motor 119 in which an output shaft 120 is fitted to a time alignment transmission mechanism 100 which the engine E contains, and a control part which calculates a load on the engine E and controls operation of the motor 119. When the control part determines that an excessive load has occurred on the engine E, or, when determines that the engine E is in a low speed rotation area and an output torque required for work is insufficient, the motor 119 is configured to operate.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a work vehicle, and more particularly to a work vehicle including an engine and having a work machine attached thereto.

  For example, a tractor is widely used as a work vehicle for performing various farm work. A work machine corresponding to the type of work is attached to the tractor. For example, a rotary tiller is used to cultivate fields, and a trencher is used to dig grooves. For driving a rotary tiller, a trencher or the like, the power of an engine provided for driving the tractor is used. In addition to driving the tractor, the engine is subjected to driving loads such as a rotary tiller and a trencher. Therefore, various measures for reducing the engine load are studied.

  Although it is not a tractor in Patent Document 1, a traveling device that travels below the traveling chassis, a reaper that harvests and transports the culm at the front, and a reaper from the reaper on the upper side. Provided with a threshing machine for receiving and threshing, a combine provided with a traveling device, a reaping machine, an engine for rotationally driving the threshing machine, an assist motor and the like, the traveling device, a reaper, and a threshing A combine transmission device is disclosed in which a control device is provided in which each engine and assist motor is independently selected and rotated and controlled in each working unit.

JP 2004-105040 A

  According to the combine transmission device of Patent Document 1, the reaping machine, the threshing machine, and the traveling apparatus can be switched to an electric motor independently depending on the load conditions, and can be operated efficiently.

  However, in the combine transmission device of Patent Document 1, each working unit is rotationally driven by either the drive by the engine or the assist motor, and it is impossible to assist the power of the engine. Furthermore, in the combine transmission device of Patent Document 1, the reaping machine, the threshing machine, and the traveling device are configured as a two-line transmission device that can be rotated by an assist motor and rotated by an engine. In addition, the structure of power transmission and the control of power switching are complicated.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a work vehicle that can assist engine power in a timely manner with a simple configuration.

  Therefore, the present invention provides a motor in which an output shaft is attached to a timing transmission mechanism provided in the engine, and a load of the engine in a work vehicle including the engine and attached with a work machine. A control unit that controls operation, and when the control unit determines that an overload has occurred in the engine, or the engine is in a low-speed rotation range and the output torque required for work is insufficient. If it is determined, the motor is configured to operate.

  The timing transmission mechanism including a crank gear, an idle gear that meshes with the crank gear, and a cam gear that meshes with the idle gear further includes a drive gear that meshes with the cam gear, and the output gear is connected to the drive gear. Is attached.

  Further, the output shaft extends in parallel with the crankshaft to which the crank gear is attached, and the motor is disposed on the side of the engine.

  Further, the output shaft is constituted by a spline shaft.

  Furthermore, the work vehicle further includes a connection / disconnection device that connects / disconnects the timing transmission mechanism and the output shaft, and when the control unit determines that the engine is not overloaded, The power from the timing transmission mechanism to the output shaft is configured to be cut off by the connection / disconnection device.

  According to the present invention, in a work vehicle equipped with an engine and equipped with a work implement, the motor in which the output shaft is attached to the timing transmission mechanism provided in the engine, the engine load is calculated, and the operation of the motor is controlled. A control unit, and when the control unit determines that an overload has occurred in the engine, or when it is determined that the engine is in a low speed rotation range and the output torque necessary for work is insufficient, the motor Therefore, it is possible to provide a work vehicle capable of assisting the power of the engine in a timely manner with a simple configuration.

  Further, the timing transmission mechanism including the crank gear, the idle gear that meshes with the crank gear, and the cam gear that meshes with the idle gear further includes a drive gear that meshes with the cam gear, and the output shaft is attached to the drive gear. Thus, it is possible to provide a work vehicle that can reliably assist the power of the engine in a timely manner with a simple configuration.

  According to the configuration in which the output shaft extends in parallel with the crankshaft to which the crank gear is attached and the motor is arranged on the side of the engine, the existing configuration and the space are effectively utilized, and the engine It is possible to provide a work vehicle capable of reliably assisting power in a timely manner.

  Since the output shaft is composed of a spline shaft, it is possible to provide a work vehicle that can assist the power of the engine more reliably and in a timely manner with a simple configuration.

  The work vehicle further includes a connection / disconnection device that connects and disconnects the timing transmission mechanism and the output shaft. When the control unit determines that the engine is not overloaded, the work vehicle transmits the output shaft. Since the power to the vehicle is cut off by the connecting / disconnecting device, a work vehicle is provided that can reduce the engine load more easily and assist the engine power in a timely manner with a simple configuration. be able to.

It is the side view by which the form with which the rotary cultivator as an example of a working machine was mounted | worn with the tractor as an example of the working vehicle which concerns on this embodiment was shown. It is the top view in which the outline of the inside of a cabin and the periphery was shown. It is a top view of an operation panel. It is the disassembled perspective view which illustrated the structure of the principal part of the power source which concerns on this embodiment. It is the schematic which illustrated the positional relationship of each gear. It is the skeleton figure which illustrated the power transmission system of the tractor. It is a principal part block diagram of the control system of a tractor. It is a flowchart of the control method of a tractor. It is the schematic by which an example of the fluctuation | variation of the engine load factor was shown. It is the schematic by which an example of the output characteristic map (engine speed-output torque diagram) was shown. It is a principal part block diagram of the control system of the tractor which concerns on a modification. It is a flowchart of the control method of the tractor concerning a modification.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing a form in which a rotary cultivator 30 as an example of a work machine is mounted on a tractor 10 as an example of a work vehicle according to the present embodiment. The working machine mounted on the tractor 10 is not limited. In addition to the rotary tiller 30, there are substitute oysters, steep cultivators, plows, broadcasters, roll balers, manual spreaders, trailers, and the like. In the following, for convenience of explanation, the left side in FIG. 1 which is the traveling direction of the tractor 10 is defined as the front direction, and is orthogonal to the traveling direction and extends to the near side and the far side in FIG. The direction is the left-right direction.

  A tractor 10 illustrated in FIG. 1 includes an engine E, a battery BT, a generator (not shown), a radiator, a cooling fan, an exhaust treatment device, an air cleaner, and the like inside a bonnet 11. The tractor 10 includes, for example, an opening / closing shaft having a left / right direction as a fulcrum at an upper part on the rear side of the hood 11. The bonnet 11 is configured to be openable and closable with respect to the machine body with the opening and closing shaft as a fulcrum. The engine E, the battery BT, the generator, and the radiator are placed on the chassis 12. As the engine E, for example, an electronically controlled common rail diesel engine is used. The common rail is also called a pressure accumulation type. The generator is coupled to the output portion of the engine E so as to operate using the engine E as power. Battery BT is connected to a generator. The tractor 10 is configured such that electricity generated by the generator is stored in the battery BT.

  The tractor 10 includes front wheels 13 and 13 on the left and right sides of the front part corresponding to the traveling direction of the airframe, and includes rear wheels 14 and 14 on the left and right sides of the rear part, respectively. That is, the tractor 10 is supported so that the traveling machine body can travel by the wheels. Fenders 15 and 15 are provided so as to cover the left and right rear wheels 14 and 14 from above and from the inside of the tractor 10, respectively. The tractor 10 may have a configuration in which a crawler is used for the traveling device.

  The tractor 10 includes a driving unit behind the hood 11. More specifically, a dashboard 16 is provided behind the hood 11 via an air cut plate (not shown). The dashboard 16 is provided with an instrument panel 40 as a display unit for displaying speed, fuel remaining amount, and the like. A steering column cover 17 is provided adjacent to the rear of the dashboard 16. A steering wheel 18 projects from the upper end of the steering column cover 17.

  A driver's seat 20 is provided behind the steering column cover 17 at a predetermined distance. The driver's seat 20 is disposed between the left and right fenders 15 and 15. The driver's seat 20 and the steering wheel 18 are covered with a cabin 19. That is, the above-described operation unit is configured by the cabin 19.

  The tractor 10 is not limited to the configuration having the cabin 19, and may be configured such that ROPS (Roll-Over Protective Structures) protrudes upward from the rear ends of the left and right fenders 15, 15. .

  A fuel tank 21 for supplying fuel to the engine E is provided below the cabin 19. The position of the fuel tank 21 is not limited, and may be, for example, the side surface of the cabin 19 or the rear of the driver seat 20. A fuel supply path (not shown) from the fuel tank 21 to the engine E is connected to the fuel pump, the common rail, and a plurality of injectors connected to the common rail via a fuel filter. It is connected to each of a plurality of cylinders. The fuel pump for supplying fuel is configured to pump the fuel in the fuel tank 21 to the common rail. The common rail is configured to store high-pressure fuel. The electromagnetic opening / closing control type fuel injection valve is configured to be opened / closed so that high-pressure fuel in the common rail is injected from the injector into each cylinder of the engine E.

  Below the driver's seat 20, a transmission case TM having a transmission as a transmission mechanism (not shown) that changes the traveling speed of the tractor 10 continuously, for example, is disposed. The transmission case TM is fixed to the rear part of the chassis 12. The transmission has a function of transmitting the power of the engine E to the rear wheels 14 and 14. The tractor 10 may be configured so that the power of the engine E is transmitted to the front wheels 13 and 13.

  On the rear upper surface of the transmission case TM, for example, a hydraulic work machine lifting mechanism 22 for lifting and lowering the rotary tiller 30 mounted as a work machine is attached. The work implement lifting mechanism 22 is not limited to a hydraulic type, and may be a mechanical type using a gear, for example, as long as the work implement can be raised and lowered.

  The rotary tiller 30 is connected to the rear of the transmission case TM of the tractor 10 via a three-point link mechanism including a pair of left and right lower links 23 and 23 and a top link 24. The front end sides of the left and right lower links 23 are connected to the left and right side surfaces of the rear portion of the transmission case TM so as to be swingable. The front end side of the top link 24 is swingably connected to the rear portion of the work implement lifting mechanism 22. A PTO shaft 25 (Power Take-Off shaft) for transmitting the driving force of the engine E is linked to the engine E and protrudes rearward from the rear surface of the transmission case TM.

  The work implement lifting mechanism 22 has a pair of left and right lift arms 26 and 26 that are rotated by a lifting hydraulic cylinder (not shown). The left and right lift arms 26 and 26 are connected to the left and right lower links 23 and 23 via left and right lift rods 27 and 27, respectively. Each of the left and right lift arms 26 and 26 is configured such that the rotary tiller 30 moves up and down via the left and right lift rods 27 and 27 and the left and right lower links 23 and 23, respectively, by rotating. . As described above, the rotary cultivator 30 including the rotary cultivating claws is connected to the tractor 10 according to the present embodiment through the link mechanism so as to be movable up and down.

  A lift angle sensor 28 is provided at the shaft portion of the rotating left and right lift arms 26 and 26. The lift angle sensor 28 is configured to detect the rotation angle of the left and right lift arms 26 and 26 that raise and lower the link mechanism. For example, a potentiometer is used as the sensor.

  One of the left and right lift rods 27, 27, for example, the right lift rod 27 is attached with, for example, a hydraulic tilt control mechanism 29 for controlling the left and right tilt angle of the rotary tiller 30 as a working machine. The tilt control mechanism 29 is not limited to a hydraulic type, and may be a mechanical type using a gear, for example, as long as the working machine can be raised and lowered.

  The tilt control mechanism 29 includes, for example, a double-acting hydraulic cylinder and a piston rod. A part of the right lift rod 27 connected to the right lift arm 26 and the right lower link 23 is constituted by a hydraulic cylinder and a piston rod. Therefore, the length of the right lift rod 27 provided with the inclination control mechanism 29 is configured to be adjustable in expansion and contraction. And the horizontal attitude | position with respect to the tractor 10 of the rotary tiller 30, ie, a roll angle, is changed when the right lift rod 27 of the left-right lift rods 27 and 27 expands / contracts.

  The rotary tiller 30 illustrated in FIG. 1 is a side drive type. However, there is no problem even if the rotary tiller 30 as a working machine connected to the work vehicle according to the present embodiment is a center drive type, for example.

  The front part of the rotary tiller 30 is detachably connected to the lower link 31 and the top link 24 detachably connected to the left and right lower links 23 and 23 of the three-point link mechanism of the tractor 10. An upper connecting portion 32 is provided. A main beam (not shown) extending in a cylindrical shape in the left-right direction of the rotary tiller 30 is connected to the rear end of the lower connecting portion 31. On the other hand, a center case (not shown) located at a substantially central portion in the left-right direction of the rotary tiller 30 is rotatably connected to the lower end of the upper connecting portion 32. The main beam extends on both sides of the center case in the left-right direction.

  A drive input shaft 33 protrudes from the front surface of the center case. The drive input shaft 33 is interlocked with the PTO shaft 25 via a universal joint shaft 34 that can be expanded and contracted. The center case incorporates a power transmission mechanism such as a bevel gear (not shown) that transmits the power of the drive input shaft 33 extending in the front-rear direction in the left-right direction. The main beam includes a power transmission shaft that extends in the left-right direction and is pivotally connected to the power transmission mechanism.

  The upper part of the transmission side case 35 extending substantially in the vertical direction is fixed to one end of the main beam extending in the left-right direction. A claw shaft rotor 36 extending in the left-right direction is rotatably provided at the lower portion of the transmission side case 35. A plurality of claws 37 extending radially in the radial direction are attached to the claw shaft rotor 36.

  Each of the output end of the power transmission shaft and the input end of the claw shaft rotor 36 protrudes to the inside of the transmission side case 35. Sprockets (not shown) are fixed to the output end of the power transmission shaft and the input end of the claw shaft rotor 36, respectively. The sprockets are interlocked and connected by an endless chain (not shown).

  In this way, in the rotary tiller 30, the power input from the PTO shaft 25 via the universal joint shaft 34 is transmitted to the drive input shaft 33, the power transmission mechanism, the power transmission shaft, the endless chain, and the claw shaft rotor 36. It is configured to be.

  A rotary main cover 38 is provided so as to surround the rotation locus L1 of the claw shaft rotor 36 and the claw 37. The rotary main cover 38 includes an upper surface cover disposed so as to cover the upper side of the rotation locus L1 of the claw 37 in the left-right direction and a pair of left and right side covers provided at both left and right ends of the upper surface cover. A rear cover 39 is attached to the rear end of the rotary main cover 38 via a hinge (not shown) extending in the left-right direction so as to cover the rear of the rotation locus L1 of the claw 37. The rear cover 39 is configured to be rotatable about a hinge.

  Next, the structure of the driver's seat 20 and its surroundings will be described. FIG. 2 is a plan view schematically showing the inside and the periphery of the cabin 19. As described above, the dashboard 16 is provided with the instrument panel 40, and the steering column cover 17 is provided with the substantially round steering 18 in a plan view.

  On the right side of the steering column cover 17 is provided an accelerator lever 50 for setting and holding the output rotational speed of the engine E. Below the accelerator lever 50 is provided a work implement lifting lever 71 for raising and lowering the work implement such as the rotary tiller 30 and the like by a single operation. On the left side of the steering column cover 17, a reverser lever 51 (forward / reverse switching lever) for switching the traveling direction of the tractor 10 between forward and reverse is provided. On the lower right side of the steering column cover 17, left and right brake pedals 52, 52 for braking the tractor 10 are provided. On the lower left side of the steering column cover 17, a clutch pedal 53 for operating a main clutch for interrupting power transmission from the engine E is provided.

  The entire upper surface of the floor in front of the driver's seat 20 is substantially flat. An accelerator pedal 54 for adjusting the rotational speed of the engine E or the vehicle speed is provided on the floor on the right side of the steering column cover 17.

  On the left side of the driver's seat 20, an auxiliary transmission lever 55 is provided for switching a transmission ratio of a traveling auxiliary transmission gear mechanism (not shown) in the transmission case TM (see FIG. 1). A PTO speed change lever 56 for switching the rotational speed of the PTO shaft 25 connected to a PTO speed change mechanism (not shown) in the transmission case TM (see FIG. 1) is provided below the driver seat 20 on the left side. Yes.

  On the right side of the driver's seat 20, an armrest 57 is provided for an operator sitting on the driver's seat 20 to put his arms and elbows. The position of the armrest 57 is configured to be adjustable up and down and up and down. The front part of the armrest 57 is connected to a speed change mechanism in the transmission case TM (see FIG. 1), and a main speed change lever 58 for accelerating / decelerating the traveling speed of the tractor 10 and a stepless fine adjustment of the vehicle speed. For example, a speed adjustment dial 59 is provided.

  The armrest 57 is further provided with a work implement lifting switch 72 for raising and lowering the work implement such as the rotary tiller 30 and the like by a single operation. The work machine up / down switch 72 includes a rise button 72u and a down button 72d.

  The armrest 57 is further provided with a PTO drive switch 73 which is connected to a PTO clutch (not shown) and used for driving the PTO. The PTO drive switch 73 is configured to connect and disconnect the PTO clutch and switch the PTO shaft 25 between an operating state and a non-operating state. In other words, when the PTO shaft 25 is in an operating state, the PTO clutch is connected, and when the condition is satisfied, the PTO shaft 25 rotates at the rotational speed selected by the PTO speed change lever 56. Therefore, the operating state of the PTO shaft 25 includes both a rotating state and a stopped state. On the other hand, when the PTO shaft 25 is not in operation, the PTO shaft 25 stops. When the PTO drive switch 73 is configured to be in an activated state when it is turned to the left or right while being pressed, and to be inactivated when it is pressed once in the activated state, the PTO shaft 25 is instantaneously operated with a simple operation. Can be stopped and operability is good.

  On the left side of the armrest 57 is electrically connected to an actuator such as a lifting hydraulic cylinder of the work implement lifting mechanism 22, and the working machine such as the rotary tiller 30 connected to the work implement lifting mechanism 22 is driven by driving the actuator. A work machine up / down lever 74 for raising and lowering is provided.

  The work implement up / down lever 74 may be configured to be used in combination with the work implement lift lever 71 or the work implement lift switch 72. For example, when the up button 72u is pressed, the work implement is raised to the uppermost position, and when the lower button 72d is pressed, the work implement is lowered to a height corresponding to the set position of the work implement up / down lever 74. It may be configured. Further, when the work implement up / down lever 74 is set at the uppermost position, the work implement may be configured not to be lowered when the work implement lift lever 71 or the work implement lift switch 72 is pressed. With these configurations, the work implement can be lowered to a desired position by a single operation of the work implement lift lever 71 and the work implement lift switch 72, and the operability is good.

  A PTO interlocking changeover switch 75 is provided behind the armrest 57. The PTO interlocking changeover switch 75 is a changeover switch for switching between the rotation state and the stop state of the PTO shaft 25 between interlocking and non-interlocking when the left and right lift arms 26 and 26 of the lifting device are lifted. Here, the non-interlocking is a setting in which, when the PTO shaft 25 is in the rotating state, the PTO shaft 25 is maintained in the rotating state regardless of the lifting / lowering of the working machine connected to the lifting device. On the other hand, the interlocking is a setting in which the PTO shaft 25 is automatically brought into a stopped state from a rotating state when the work machine is raised to a predetermined height or higher. In the interlocking, when the working machine is lowered below a predetermined height, the PTO shaft 25 is set to be automatically rotated when the PTO shaft 25 is in an operating state by switching by the PTO drive switch 73. Yes.

  As an example in which the interlocking functions and the PTO shaft 25 is changed to a stopped state, when the work implement is raised to the highest position by the operation of the work implement lift lever 71, the work implement lift switch 72, etc. And when the working machine is raised to a predetermined height or more by the machine up / down lever 74. It should be noted that the front wheels 13 and 13 (see FIG. 1) have functions such as turning and lifting in which the work implement automatically rises when the front wheels 13 and 13 (see FIG. 1) are operated beyond a certain angle, In the case where the tractor 10 has, the interlocking may function similarly.

  In addition, the PTO interlocking changeover switch 75 may be configured to be switchable also with respect to the correspondence relationship between the operation of the clutch pedal 53 and the operation of the PTO shaft 25. In the present embodiment, when the clutch pedal 53 is depressed, the rotation of the PTO shaft 25 and the traveling of the tractor 10 are stopped at the same time, regardless of whether the above-described interlocking or non-interlocking of the PTO interlocking changeover switch 75 is selected. It is configured as follows. There, independence may be provided as a driving method of the PTO shaft 25. That is, when the position of the PTO interlocking switch 75 is independent, the operation of the clutch pedal 53 and the operation of the PTO shaft 25 are independent, so that the rotation of the PTO shaft 25 does not stop even when the clutch pedal 53 is depressed. It may be configured.

  An operation panel 60 is provided on the right side of the armrest 57. FIG. 3 is a plan view of the operation panel 60. 3 includes a depth setting dial 61, a tilt setting dial 62, a tilt control switch 63, a raised position setting dial 64, a depth control switch 65, a lower cushion setting dial 66, a link changeover switch 67, An auto sensitivity setting switch 68, a tilt manual lever 69, and the like are provided.

  The depth setting dial 61 sets the depth when the tilling depth of the rotary tiller 30 is automatically controlled. For example, the depth setting dial 61 is configured to rotate in the clockwise direction so that the depth of the rotary tiller 30 is set larger.

  The tilt setting dial 62 sets the left and right tilts when the tilt of the rotary tiller 30 is automatically controlled. For example, the tilt setting dial 62 rotates clockwise with reference to the center of rotation in the clockwise direction and rotation in the counterclockwise direction as a reference (horizontal), and the inclination of the rotary tiller 30 is lower right. It is configured to be a setting.

  The tilt control switch 63 switches the tilt control method of the rotary tiller 30. As a control method, there are horizontal automatic control, slope automatic control, and no control (manual). In the horizontal automatic control, the rotary tiller 30 is kept at a certain angle set by the tilt setting dial 62 with respect to the horizontal plane. Inclined land automatic control is to keep the rotary tiller 30 at a certain angle set by the tilt setting dial 62 with respect to the inclination of the ground. “Manual” means that the rotary tiller 30 is kept at a certain angle set by the tilt setting dial 62 with respect to the tractor 10. The tilt control switch 63 is configured to switch to horizontal automatic control, slope automatic control, and manual each time it is pressed, for example.

  The raising position setting dial 64 is for setting the maximum raising position of the rotary tiller 30. That is, the raising position setting dial 64 sets the uppermost position when the rotary tiller 30 is lifted by the work implement up / down lever 74, the work implement lift lever 71, the work implement lift switch 72, the back raising, the turning up and the like. To do. The raising position setting dial 64 is configured so that, for example, the maximum raising position of the rotary tiller 30 is set higher by rotation in the clockwise direction.

  The depth control switch 65 switches the control method of the tilling depth of the rotary tiller 30. As control methods, there are automatic depth control, automatic load control, and no control (manual). In the depth automatic control, the plowing depth of the rotary tiller 30 is maintained at a certain depth set by the depth setting dial 61. In the automatic load control, the plowing depth of the rotary tiller 30 is kept as much as possible at a certain depth set by the depth setting dial 61 and the plowing depth is controlled shallowly when the engine E is under a high load. . Note that the depth setting dial 61 is configured not to function manually. The depth control switch 65 is configured to switch to automatic depth control, automatic load control, and manual each time it is pressed, for example.

  The lower cushion setting dial 66 sets the height at which the lower cushion of the rotary tiller 30 starts to be effective when the lowering operation is performed by the work implement elevating lever 71 and the work implement elevating switch 72. This is a mechanism for preventing dashing or the like by slowing the descending speed of the rotary tiller 30 immediately before the ground contact. Here, dashing is a phenomenon that occurs when a tilling claw hits a hard ground field in particular, and a work vehicle that has received a reaction force of the excavation resistance of the tilling nail is strongly pushed forward. The lower cushion setting dial 66 is configured so that, for example, the position at which the lower cushion of the rotary tiller 30 starts to operate is set higher by rotation in the clockwise direction.

  The link changeover switch 67 selects the specifications of the three-point link mechanism (left and right lower links 23, 23) used for connecting the rotary tiller 30. More specifically, the link changeover switch 67 is switched depending on the difference between the width between the left and right lower links 23 and 23 and the position of the work machine mounting holes of the left and right lower links 23 and 23. And the correction | amendment according to the specification of the selected three-point link mechanism is performed, and the raising / lowering operation | movement of the rotary tiller 30 is changed. For example, each time the link changeover switch 67 is pressed, the (width, hole position) is (wide (718 mm), front), (wide, rear), (narrow (600 mm), front), and (narrow, It is configured to switch to (after).

  The auto sensitivity setting switch 68 switches the sensitivity of the auto rotary, that is, the operation sensitivity of the automatic tilling depth control. The automatic sensitivity setting switch 68 adjusts the operation sensitivity according to the hardness of the field, for example, and enables the tilling depth control with the operation sensitivity according to the field conditions. For example, when the ground of the field is hard, the sensitivity of the auto rotary is made insensitive. For example, each time the auto sensitivity setting switch 68 is pressed, the switch is switched between standard and insensitive.

  The tilt manual lever 69 is used to manually change and adjust the left and right tilt of the rotary tiller 30. Note that when the tilt of the rotary tiller 30 is automatically controlled, the tilt of the rotary tiller 30 is changed only while the tilt manual lever 69 is being operated. On the other hand, when the tilt of the rotary tiller 30 is not automatically controlled, the tilt of the rotary tiller 30 relative to the tractor 10 can be arbitrarily set by operating the tilt manual lever 69. The tilt manual lever 69 is configured such that, for example, when the tilt manual lever 69 is operated upward (backward from the operator), the tilt of the rotary tiller 30 is set to the lower right.

  Next, the configuration of the power source included in the tractor 10 will be described in detail. FIG. 4 is an exploded perspective view illustrating the structure of the main part of the power source according to this embodiment. The engine E as a power source of the tractor 10 is a so-called OHV (OverHead Valve) system and includes a timing transmission mechanism 100. Here, the side on which the timing transmission mechanism 100 is disposed is the front surface of the engine E, and description will be made in the left-right direction as viewed from the front side of the engine E.

  A gear case 102 that houses the timing transmission mechanism 100 is fixed to the front surface of the cylinder block 101 that forms the skeleton of the engine E. The front surface of the gear case 102 is covered with a gear case cover (not shown). The gear case 102 is covered with a gear case cover to form a timing gear chamber. The gear case 102 is formed with a plurality of holes through which shafts that are rotatably attached to the cylinder block 101 pass in the front-rear direction.

  A front end of the crankshaft 103 protrudes from a hole formed in a substantially central lower portion of the front surface of the gear case 102. A flywheel 104 is attached to the rear end of the crankshaft 103 extending in the front-rear direction of the engine E. The flywheel 104 is located on the rear surface of the cylinder block 101. The power of the crankshaft 103 is configured to be transmitted to the transmission via the flywheel 104 that stabilizes its rotation. On the other hand, a crank gear 105 is fixed to the front end side of the crankshaft 103.

  An idle shaft 106 extending in a direction parallel to the crank shaft 103 is fixed to the gear case 102 on the front surface of the gear case 102 in the upper left region of the crank gear 105. An idle gear 107 is rotatably attached to the idle shaft 106.

  A front end of the camshaft 108 protrudes from a hole formed in the front surface of the gear case 102 in the right region of the idle gear 107. The camshaft 108 extends in the front-rear direction of the engine E, that is, in a direction parallel to the crankshaft 103. A cam gear 109 is fixed to the front end of the cam shaft 108. On the other hand, the cam shaft 108 is provided with a plurality of cam ridges 110 whose radial dimensions periodically change. A tappet 111 is provided on the cam crest 110, and a push rod 112 is provided on the tappet 111. The tappet 111 has a function of converting a rotational motion in which the cam shaft 108 rotates and the outer diameter thereof periodically changes by the cam crest 110 into a linear reciprocating motion in the vertical direction. The push rod 112 interlocked with the tappet 111 is configured to open an intake valve (not shown) and an exhaust valve (OHV described above) connected to the rocker arm by pushing a rocker arm (not shown).

  As described above, the timing transmission mechanism 100 includes at least the crank gear 105, the idle gear 107, and the cam gear 109.

  A fuel injection pump 113 is attached to the rear surface of the left end of the gear case 102. A fuel injection pump shaft 114 provided in the fuel injection pump 113 projects from a hole formed in the front surface of the gear case 102 in the upper left region of the idle gear 107. The fuel injection pump shaft 114 also extends in the front-rear direction of the engine E, that is, in the direction parallel to the crankshaft 103. A fuel injection pump gear 115 is fixed to the front end of the fuel injection pump shaft 114. As described above, the tractor 10 pumps the fuel in the fuel tank 21 (see FIG. 1) to the common rail by rotating the fuel injection pump gear 115 and the fuel injection pump shaft 114 to drive the fuel injection pump 113. And high pressure fuel is stored in the common rail.

  In the configuration according to the present embodiment, the drive gear 116 is further provided on the front surface of the gear case 102 in the right region of the cam gear 109. Bearings 117 and 117 are attached to the drive gear 116 on the front side and the rear side, respectively. The drive gear 116 is rotatably attached to the gear case 102 by bearings 117 and 117. A hole extending in the front-rear direction is formed at the center of the drive gear 116. And it is preferable that the spline (tooth-shaped groove | channel) is formed in the internal peripheral surface of the hole. Therefore, the drive gear 116 is preferably configured to have the spline hole 118.

  In the configuration according to the present embodiment, a motor 119 is further provided on the rear surface of the gear case 102 in the right region of the cam gear 109. For the motor 119, for example, a direct winding brush motor is used. The output of the motor 119 is preferably 10 kW or more and 18 kW or less. The output shaft 120 of the motor 119 is attached to the timing transmission mechanism 100. The power of the engine E can be assisted with such a simple configuration.

  A spline is preferably formed on the outer peripheral surface of the output shaft 120. Therefore, the output shaft 120 of the motor 119 is preferably configured as the spline shaft 121. When the output shaft 120 is configured by the spline shaft 121, when the output shaft 120 is attached to the drive gear 116, the spline hole 118 and the spline shaft 121 are engaged with each other, so that power is transmitted more reliably. Therefore, in the present embodiment, it is possible to provide the tractor 10 that is capable of assisting the power of the engine E more reliably in a timely manner with a simple configuration. The drive gear 116 may have a steel ball instead of a spline on the inner peripheral surface of the hole, and the steel ball may be configured to engage with the spline shaft 121.

  Regarding the positional relationship between the engine E and the motor 119, it is preferable that the output shaft 120 extends in parallel with the crankshaft 103 to which the crank gear 105 is attached, and the motor 119 is disposed on the side of the engine E. For this reason, the output shaft 120 of the motor 119 protrudes from a hole formed in the right end portion of the front surface of the gear case 102. An output shaft 120 extending in a direction parallel to the crankshaft 103 is connected to the drive gear 116. The drive gear 116 is attached so as to rotate integrally with the output shaft 120.

  In the past, there were many configurations in which a hydraulic pump was disposed at this position. In this case, the hydraulic pump is configured to operate at, for example, 25 horsepower by the power of the timing transmission mechanism 100 of the engine E. However, a space is created at this position by attaching the hydraulic pump to the transmission. Therefore, although the positional relationship between the engine E and the motor 119 is limited to the power below the hydraulic pump was operated, the existing configuration and space can be effectively used to simplify the operation. With the configuration, it is possible to provide the tractor 10 that can reliably assist the power of the engine E in a timely manner. And, by supporting the power of the engine E, it is possible to comply with the exhaust gas regulations of higher rank vehicles.

  The motor 119 is preferably disposed on the side of the engine E, that is, on the rear surface side of the gear case 102, but may be disposed on the front surface side if the motor 119 can be attached to the front surface of the engine E. Absent. Since the side of the engine E is a narrow space, if the motor 119 cannot be directly mounted on the engine E, an adapter for attaching the motor 119 may be separately provided so that the motor 119 can be attached. A gear (not shown) may be provided, and the output shaft 120 may be extended.

  An oil pump gear (not shown) is attached to the front surface of the gear case 102 in the lower left region of the crank gear 105. An oil pan (not shown) is attached under the cylinder block 101 of the engine E, and engine oil as a lubricant is stored in the oil pan. The tractor 10 is configured such that engine oil is sucked by an oil pump (not shown) to which an oil pump gear is attached, and is supplied to each lubrication point inside the engine E through an oil filter.

  Next, the arrangement of each gear described above, that is, the power transmission system will be described in detail. FIG. 5 is a schematic view illustrating the positional relationship of each gear.

  The crank gear 105 is engaged with the idle gear 107 and the oil pump gear 122. The rotational power of the crank gear 105 is configured to be transmitted to both the crank gear 105 and the oil pump gear 122. The idle gear 107 meshes with three of the crank gear 105, the cam gear 109, and the fuel injection pump gear 115. The rotational power of the crankshaft 103 is configured to be transmitted from the crank gear 105 via the idle gear 107 to both the cam gear 109 and the fuel injection pump gear 115. For this reason, the camshaft 108 and the fuel injection pump shaft 114 rotate in conjunction with the crankshaft 103. At that time, for example, the gear ratio between the gears is set so that the camshaft 108 and the fuel injection pump shaft 114 make one rotation with respect to two rotations of the crankshaft 103.

  In the configuration according to the present embodiment, the cam gear 109 and the drive gear 116 are engaged with each other. In this way, one power transmission system directly connected to the engine E is formed, and the output shaft 120 of the motor 119 rotates in conjunction with the crankshaft 103.

  The crank gear 105, the idle gear 107, the cam gear 109, the fuel injection pump gear 115, the oil pump gear 122, and the drive gear 116 are accommodated in a gear case. Therefore, these gear groups of the timing transmission mechanism 100 form a line and constitute a gear train of the engine E. Each of these gears is constituted by, for example, a helical gear.

  As described above, in this embodiment, the timing transmission mechanism 100 including the crank gear 105, the idle gear 107 that meshes with the crank gear 105, the cam gear 109 that meshes with the idle gear 107, and the like has the drive gear 116 that meshes with the cam gear 109. In addition, the output shaft 120 is attached to the drive gear 116. With such a configuration, a large belt as a power transmission member is not required, and further, it does not slide like a belt, and a large torque can be transmitted by meshing each gear. Therefore, according to this embodiment, it is possible to provide a work vehicle that can reliably assist the power of the engine E in a timely manner with a simple configuration.

  Each fuel injection valve is electronically controlled based on detection signals from a crank angle sensor (not shown) that detects the rotation angle of the crankshaft 103 and a camshaft rotation angle sensor (not shown) that detects the rotation angle of the camshaft 108. Configured to be.

  Next, the internal structure of the transmission case TM and the power transmission system of the tractor 10 will be described in detail. FIG. 6 is a skeleton diagram illustrating the power transmission system of the tractor 10.

  The transmission case TM is formed in a hollow box shape as a whole. A front lid member 491 is disposed on the front surface of the transmission case TM. An intermediate partition wall 493 that partitions the interior of the transmission case TM forward and backward is formed in front of the transmission case TM, and a rear partition wall 494 that partitions the interior of the transmission case TM forward and backward is formed behind it. An intermediate auxiliary plate 498 is detachably fastened in front of the rear partition wall 494 with a gap in the front-rear direction. A rear lid member 492 is disposed on the rear surface of the transmission case TM. A work case hydraulic pump 481 driven by the rotational power of the engine E and a pump case 480 housing the traveling hydraulic pump 482 are attached to the right outer surface of the transmission case TM.

  A space between the front lid member 491 inside the transmission case TM and the intermediate partition wall 493 serves as a front chamber 495. A space between the intermediate partition wall 493 and the rear partition wall 494 is an intermediate chamber 497. A rear chamber 496 is formed between the rear lid member 492 and the rear partition wall 494. Each of the front lid member 491, the intermediate partition wall 493, the intermediate auxiliary plate 498, the rear partition wall 494, and the rear cover member 492 penetrates in the front-rear direction for rotatably mounting each shaft that transmits the power of the engine E. A plurality of holes are formed. The transmission case TM is configured such that hydraulic oil (lubricating oil) moves inside the front chamber 495, the intermediate chamber 497, and the rear chamber 496.

  Inside the front chamber 495 is a hydraulic continuously variable transmission 500, a creep (ultra-low speed) transmission gear mechanism 502, a traveling auxiliary transmission gear mechanism 503, and a two-wheel drive and four-wheel drive switching mechanism that switches between two-wheel drive and four-wheel drive. 504 are arranged. Inside the intermediate chamber 497, a forward / reverse switching mechanism 501 for switching the rotational power from the hydraulic continuously variable transmission 500 to either the forward rotation or the reverse rotation direction is disposed. Inside the rear chamber 496, the PTO transmission mechanism 505 that appropriately changes the rotational power from the engine E and transmits it to the PTO shaft 25, the creep transmission gear mechanism 502, and the traveling auxiliary transmission gear mechanism 503 is routed. A rear wheel differential gear mechanism 506 for transmitting rotational power to the left and right rear wheels 14, 14 is disposed.

  A main shaft 327 projecting rearward from a flywheel 104 (not shown) (see FIG. 4), which is directly connected to the crankshaft 103 on the rear surface of the engine E, is transmitted through a power transmission shaft 329 having universal shaft joints at both ends. A main transmission input gear 513 is connected to a main transmission input shaft 328 mounted on the rear end side so as to protrude forward from the front surface (front lid member 491) side of the case TM so as not to be relatively rotatable. Therefore, the tractor 10 is configured such that the rotational power of the engine E is transmitted to the main transmission input shaft 328 of the transmission case TM via the main driving shaft 327 and the power transmission shaft 329.

  In the tractor 10, the rotational power of the engine E is appropriately changed by the hydraulic continuously variable transmission 500, the creep transmission gear mechanism 502, and the traveling auxiliary transmission gear mechanism 503 in the transmission case TM. It is transmitted to the dynamic gear mechanism 506 and configured to drive the left and right rear wheels 14 and 14. On the other hand, in the tractor 10, the speed change power via the creep transmission gear mechanism 502 and the traveling auxiliary transmission gear mechanism 503 is changed from the two-wheel drive / four-wheel drive switching mechanism 504 to the front wheel output shaft 330, the front wheel drive shaft 331, and the front wheel transmission shaft. 508 is also transmitted to a front-wheel differential gear mechanism 507 in a front axle case (not shown) to drive the left and right front wheels 13 and 13.

  The hydraulic continuously variable transmission 500 is cylindrical on an input transmission shaft 511 in which an input transmission gear 514 that always meshes with a main transmission input gear 513 is fixed to the rear end side (between the intermediate auxiliary plate 498 and the rear partition wall 494). The main transmission output shaft 512 of the shape is of an in-line type arranged concentrically. Therefore, the tractor 10 is configured such that the rotational power of the main transmission input shaft 328 is transmitted to the hydraulic continuously variable transmission 500 via the main transmission input gear 513, the input transmission gear 514, and the input transmission shaft 511. Yes.

  Here, the pump drive gear 484 attached to the pump drive shaft 483 that drives both the working machine hydraulic pump 481 and the traveling hydraulic pump 482 so as not to rotate relative to each other is connected to the main shift via the flat gear mechanism 485. The main transmission input gear 513 of the input shaft 328 is connected. On the other hand, a pump shaft of a lubricating oil pump 518 that is disposed between the intermediate auxiliary plate 498 and the rear partition wall 494 and supplies lubricating hydraulic oil to the hydraulic continuously variable transmission 500, the forward / reverse switching mechanism 501 and the like. The pump gear 520 fixed to 519 is always engaged with the input transmission gear 514 of the input transmission shaft 511. Therefore, the tractor 10 is configured such that the working machine hydraulic pump 481, the traveling hydraulic pump 482, and the lubricating oil pump 518 are driven by the rotational power of the engine E.

  The hydraulic continuously variable transmission 500 is of a variable displacement type provided with a pump swash plate 523 that adjusts the amount of hydraulic oil supplied by changing an inclination angle with respect to the axis of the input transmission shaft 511 by a main transmission hydraulic cylinder (not shown). A hydraulic pump unit 521 and a constant displacement type hydraulic motor unit 522 that is operated by high-pressure hydraulic oil discharged from the hydraulic pump unit 521 are provided.

  The tractor 10 changes from the hydraulic pump unit 521 to the hydraulic motor unit 522 by changing the inclination angle of the pump swash plate 523 by driving the main transmission hydraulic cylinder according to the operation amount of the main transmission lever 58 (see FIG. 2). The amount of hydraulic oil supplied is changed and adjusted, and the main transmission operation of the hydraulic continuously variable transmission 500 is performed. The tractor 10 continuously shifts the hydraulic motor unit 522 according to the inclination angle of the pump swash plate 523 with respect to the axis of the input transmission shaft 511 so that the shifted power is transmitted to the main transmission output shaft 512. It is configured. A main transmission high-speed gear 516, a main transmission reverse gear 517, and a main transmission low-speed gear 515 are attached to the main transmission output shaft 512 so as not to rotate relative to each other for traveling output.

  On the main transmission input shaft 328, a planetary gear mechanism 526 that is a forward high-speed gear mechanism and a low-speed gear pair 525 that is a forward low-speed gear mechanism are disposed in the middle chamber 497. The planetary gear mechanism 526 supports a sun gear 531 that is attached to the main transmission input shaft 328 together with the input transmission gear 529 and a plurality of planetary gears 533 so as to be rotatable on the same radius. A carrier 532 attached to the shaft 328 so as not to rotate relative thereto, and a ring gear 534 having inner teeth on the inner peripheral surface and attached to the main transmission input shaft 328 together with the output transmission gear 530. ing. The sun gear 531 meshes with each planetary gear 533 of the carrier 532 from the inside of the radius. The inner teeth of the ring gear 534 mesh with the planetary gears 533 from the outside of the radius.

  The input-side low-speed gear 527 and the output-side low-speed gear 528 constituting the low-speed gear pair 525 have an integral structure, and rotate between the planetary gear mechanism 526 and the main transmission input gear 513 around the main transmission input shaft 328. It is attached as possible.

  The forward / reverse switching mechanism 501 is provided on the travel relay shaft 535. The traveling relay shaft 535 includes, for example, a forward high speed gear 540 connected by a wet multi-plate forward high-speed hydraulic clutch 539, a reverse gear 542 connected by a wet multi-plate reverse hydraulic clutch 541, and a wet multi-plate type. The forward low-speed gear 538 connected by the forward low-speed hydraulic clutch 537 is attached. The tractor 10 is configured so that a power connection state and a power disconnection state of the forward high speed hydraulic clutch 539, the reverse hydraulic clutch 541, and the forward low speed hydraulic clutch 537 are switched by operation of the reverser lever 51 (see FIG. 2). Yes.

  The main transmission low speed gear 515 of the main transmission output shaft 512 is always engaged with the input low speed gear 527 of the low speed gear pair 525 on the main transmission input shaft 328 side, and the output low speed gear 528 is always engaged with the forward low speed gear 538. . When the reverser lever 51 is operated to the forward side, the tractor 10 has the forward low-speed hydraulic clutch 537 in a power connection state, the forward low-speed gear 538 and the travel relay shaft 535 are coupled so as not to be relatively rotatable, The forward and low-speed rotational power is transmitted from the output shaft 512 to the travel relay shaft 535 via the low-speed gear pair 525.

  The main transmission high speed gear 516 of the main transmission output shaft 512 is always engaged with the input side transmission gear 529 of the planetary gear mechanism 526 on the main transmission input shaft 328 side, and the output side transmission gear 530 is always engaged with the forward high speed gear 540. . When the reverser lever 51 is further operated to the forward side, the forward high-speed hydraulic clutch 539 is in a power connection state, and the forward high-speed gear 540 and the travel relay shaft 535 are connected so as not to be relatively rotatable. It is configured so that forward high-speed rotational power is transmitted from the transmission output shaft 512 to the travel relay shaft 535 via the planetary gear mechanism 526.

  The main transmission reverse rotation gear 517 of the main transmission output shaft 512 is always meshed with the reverse gear 542. In the tractor 10, when the reverser lever 51 is operated to the reverse side, the reverse hydraulic clutch 541 is in a power connection state, the reverse gear 542 and the travel relay shaft 535 are coupled so as not to be relatively rotatable, and the main transmission output shaft The reverse rotational power is transmitted from 512 to the travel relay shaft 535.

  When the reverser lever 51 is in the neutral position, the rotational power of the travel relay shaft 535 is substantially zero (main clutch disengaged state).

  A travel relay gear 543 is attached between the forward high speed hydraulic clutch 539 of the travel relay shaft 535 and the reverse gear 542 so as not to be relatively rotatable, and the travel transmission gear 544 that is always meshed with the travel relay gear 543 is connected to the travel transmission shaft. The tractor 10 is attached to the 536 so as not to rotate relative thereto, and the tractor 10 is configured such that the rotational power of the travel relay shaft 535 is transmitted to the travel transmission shaft 536.

  The creep transmission gear mechanism 502 and the traveling auxiliary transmission gear mechanism 503 are traveling transmission gear mechanisms that shift the transmission output via the forward / reverse switching mechanism 501 in multiple stages, for example, an ultra-low speed, a low speed, and a high speed. For example, a mechanical creep transmission gear mechanism 502 and a traveling auxiliary transmission gear mechanism 503 are arranged between the traveling countershaft 545 extending coaxially with the traveling transmission shaft 536 and the auxiliary transmission shaft 546.

  The travel counter shaft 545 is connected to the travel transmission shaft 536 so as to rotate integrally therewith and is attached to the travel counter shaft 545 so as to be rotatable, and a creep gear 548 attached to the travel counter shaft 545 so as not to be relatively rotatable. A creep shifter 549 fixed between the transmission gear 547 and the creep gear 548 in the rotational direction by a spline and slidably attached in the axial direction is provided. An input-side reduction gear 551 and an output-side reduction gear 552 that constitute a reduction gear pair 550 that is rotatably attached to the auxiliary transmission shaft 546 have an integral structure, and the transmission gear 547 of the travel counter shaft 545 is input. The side reduction gear 551 is always engaged, and the creep gear 548 is always engaged with the output side reduction gear 552.

  In the tractor 10, the creep shifter 549 is slid by operating a very low speed lever (not shown) so that the transmission gear 547 is connected to the travel counter shaft 545 so as not to rotate relative to the travel power shaft 536. Is transmitted to the travel counter shaft 545 as it is. On the other hand, in the tractor 10, the creep gear 548 is connected to the travel counter shaft 545 so as not to rotate relative to the travel counter shaft 545 by the operation of the ultra-low speed lever, and the rotational power of the travel transmission shaft 536 becomes the ultra-low speed via the auxiliary transmission shaft 546. The rotating power thus transmitted is transmitted to the travel counter shaft 545.

  A low-speed relay gear 553 is provided on the front side of the travel counter shaft 545 so as not to be relatively rotatable, and a high-speed relay gear 554 is provided so as not to be relatively rotatable. A low-speed gear 555 that meshes with the low-speed relay gear 553 and a high-speed gear 556 that meshes with the high-speed relay gear 554 are rotatably attached to the auxiliary transmission shaft 546, and are rotated by a spline between the low-speed gear 555 and the high-speed gear 556. An auxiliary transmission shifter 557 that is fixed in the direction and slidable in the axial direction is attached.

  The tractor 10 travels when the auxiliary transmission lever 55 (see FIG. 2) is operated to the low speed side so that the auxiliary transmission shifter 557 slides and the low speed gear 555 is connected to the auxiliary transmission shaft 546 so as not to rotate relative thereto. The rotational power of the counter shaft 545 is configured to be transmitted to the auxiliary transmission shaft 546 at a low speed. On the other hand, in the tractor 10, when the auxiliary transmission lever 55 is operated to the high speed side, the high speed gear 556 is connected to the auxiliary transmission shaft 546 so as not to rotate relative to the auxiliary transmission shaft 546, and the rotational power of the travel counter shaft 545 becomes high. It is configured to be transmitted to the shaft 546. In the tractor 10, the super-low speed lever and the auxiliary transmission lever 55 are interlocked and connected via a check mechanism (not shown), and the auxiliary transmission lever 55 cannot be operated to the high speed side when the ultra-low speed lever is engaged. It is configured as follows.

  The tractor 10 is configured such that the rotational power of the auxiliary transmission shaft 546 is transmitted as the driving force of the left and right rear wheels 14 and 14 via the rear wheel differential gear mechanism 506. The rear wheel differential gear mechanism 506 includes a ring gear 559 that meshes with a pinion 558 provided at the rear end of the auxiliary transmission shaft 546, a differential gear case 560 provided at the ring gear 559, and a pair of differentials extending in the left-right direction. And an output shaft 561. The differential output shaft 561 is connected to a rear axle 320 to which the rear wheel 14 is attached on the front end side via a final gear 562 and the like.

  The left and right differential output shafts 561 are operated when the operation of the corresponding left and right brake pedals 52 and 52 (see FIG. 2) and the steering angle of the steering wheel 18 (see FIGS. 1 and 2) exceed a predetermined angle. Brake mechanisms 563 that brake the left and right rear wheels 14 and 14 are arranged on the left and right sides by two systems of automatic control (auto brake) of a brake cylinder (not shown) for the rear wheel 14 inside the turn. Further, the differential gear mechanism 506 for the rear wheel is engaged with a differential lock pin so as to fix the differential gear to the differential gear case 560 by depressing a differential lock pedal (not shown). And a differential lock mechanism 585 for driving the left and right differential output shafts 561 at a constant speed is provided.

  On the other hand, the driven gear 569 attached to the front wheel input shaft 568 so as not to rotate relative to the main drive gear 569 attached so as not to rotate relative to the front end side of the auxiliary transmission shaft 546 is always engaged. Further, a double speed relay gear 571 and a four-wheel drive relay gear 572 are attached to the front wheel input shaft 568 so as not to be relatively rotatable.

  The two-wheel drive / four-wheel drive switching mechanism 504 is provided on the front wheel output shaft 330, and is connected to the front wheel output shaft 330 by, for example, a wet multi-plate type double speed hydraulic clutch 573, and a double speed relay gear 571 of the front wheel input shaft 568 A double-speed gear 574 that always engages, and a four-wheel drive gear 576 that is connected to the front wheel output shaft 330 by a wet-type multi-plate four-wheel drive hydraulic clutch 575 and always meshes with the four-wheel drive relay gear 572.

  When a drive changeover switch or a drive changeover lever (not shown) is operated to the four-wheel drive side, the four-wheel drive hydraulic clutch 575 is in a power connection state, and the front wheel output shaft 330 and the four-wheel drive gear 576 cannot be rotated relative to each other. The rotational power is transmitted from the auxiliary transmission shaft 546 to the front wheel output shaft 330 via the front wheel input shaft 568 and the four-wheel drive gear 576, and the tractor 10 is a four-wheel vehicle driven by the front wheel 13 together with the rear wheel 14. It becomes a driving state. Furthermore, when the steering angle of the steering wheel 18 exceeds a predetermined angle due to a U-turn or the like, the double speed hydraulic clutch 573 is in a power connection state so that the front wheel output shaft 330 and the double speed gear 574 cannot be rotated relative to each other. The rotational power is transmitted from the auxiliary transmission shaft 546 to the front wheel output shaft 330 via the front wheel input shaft 568 and the double speed gear 574, and compared with the rotational speed of the front wheels 13 by the rotational power via the four-wheel drive gear 576. Thus, the front wheel 13 is configured to be driven at about twice the high speed.

  A front wheel output shaft 330 that protrudes forward from the lower front portion of the front lid member 491 and a front wheel transmission shaft 508 that protrudes rearward from a front axle case (not shown) are connected by a front wheel drive shaft 331. A front wheel differential gear mechanism 507 that is disposed in the front axle case and transmits the driving force to the left and right front wheels 13 and 13 includes a ring gear 578 that meshes with a pinion 577 provided on the front end side of the front wheel transmission shaft 508, A differential gear case 579 provided on the ring gear 578 and a pair of differential output shafts 580 extending in the left-right direction are provided. The differential output shaft 580 is connected to a front axle 316 to which the front wheel 13 is attached on the front end side via a final gear 581 and the like. A steering hydraulic cylinder (not shown) for power steering is provided on the outer surface of the front axle case to change the traveling direction of the front wheels 13 to the left and right by operating the steering wheel 18.

  A PTO input shaft 591 extending coaxially with the main transmission input shaft 328 is connected to the rear end side of the main transmission input shaft 328 via a PTO hydraulic clutch 590 for power transmission interruption. For example, a medium speed input gear 597, a low speed input gear 595, and a high speed input gear 596 are attached to the PTO input shaft 591 so as to be relatively non-rotatable as three-stage forward rotation and one-stage reverse rotation. A shifter gear 598 is fixed by a spline in the rotational direction and is slidably attached in the axial direction. In the tractor 10, when the PTO drive switch 73 (see FIG. 2) is operated for power connection, the PTO hydraulic clutch 590 is in a power connection state so that the main transmission input shaft 328 and the PTO input shaft 591 cannot rotate relative to each other. The rotary power is transmitted from the main transmission input shaft 328 to the PTO input shaft 591 constituting the PTO transmission mechanism 505.

  On the other hand, a PTO medium speed gear 601 that meshes with the medium speed input gear 597, a PTO low speed gear 599 that meshes with the low speed input gear 595, and a PTO high speed gear 600 that meshes with the high speed input gear 596 are rotatably attached to the PTO transmission shaft 592. It has been. Further, a pair of front and rear first PTO shift shifters 602 and 603 that are interlocked with the operation of the PTO shift lever 56 (see FIG. 2) are fixed to the PTO shift shaft 592 in the rotational direction by splines. It is slidably attached in the axial direction. Further, a PTO transmission gear 604 is fixed to the PTO transmission shaft 592.

  A PTO counter gear 605 that meshes with the PTO transmission gear 604, a PTO relay gear 606 that meshes with a PTO output gear 608 that is mounted on the PTO shaft 25 so as not to rotate relative to the PTO shaft 25, and a PTO speed change lever 56 that is neutrally operated. A PTO reverse gear 607 that meshes with the reverse shifter gear 598 that slides when the reverse PTO lever is operated to reversely rotate is attached to the PTO countershaft 593 so as not to be relatively rotatable.

  When the PTO speed change lever 56 is operated to shift the tractor 10, the pair of front and rear first PTO speed shifter 602 and second PTO speed change shifter 603 causes the PTO low speed gear 599, the PTO medium speed gear 601 and the PTO high speed gear 600. Are connected to the PTO transmission shaft 592, and low-speed to high-speed PTO transmission outputs are transmitted from the PTO transmission shaft 592 to the PTO counter shaft 593 via the PTO transmission gear 604 and the PTO counter gear 605. It is configured to be transmitted to the PTO shaft 25 via the PTO relay gear 606 and the PTO output gear 608.

  Further, in the tractor 10, when the reverse PTO lever is operated to reversely rotate, the reverse shifter gear 598 engages with the PTO reverse rotation gear 607, and the rotational power of the PTO input shaft 591 is transferred to the PTO via the reverse shifter gear 598 and the PTO reverse rotation gear 607. A reverse PTO speed change output transmitted to the counter shaft 593 is transmitted from the PTO counter shaft 593 to the PTO shaft 25 via the PTO relay gear 606 and the PTO output gear 608. In the tractor 10, the PTO speed change lever 56 and the reverse rotation PTO lever are interlocked and connected via a check mechanism (not shown), and when the PTO speed change lever 56 is operated in a position other than neutral, the reverse rotation PTO lever enters the reverse direction. It is configured so that it cannot be operated.

  A vehicle speed tuning input gear 565 that is always meshed with a power branch gear 566 that is mounted on the auxiliary transmission shaft 546 so as not to rotate relative to the auxiliary transmission shaft 546 is mounted on the front end side of the vehicle speed tuning shaft 564 so as not to rotate relative to it. A vehicle speed tuning relay gear 609 that always meshes with the vehicle speed tuning output gear 610 is fixed to the rear end portion of the vehicle speed tuning shaft 564. A vehicle speed tuning shifter 611 is fixed to the PTO shaft 25 by a spline so as to be slidable in the axial direction. In the tractor 10, when a PTO vehicle speed tuning lever (not shown) is operated and operated, the vehicle speed tuning shifter 611 slides, and the vehicle speed tuning output gear 610 is connected to the PTO shaft 25. The vehicle speed tuning output via 564 is configured to be transmitted to the PTO shaft 25.

  In this way, the tractor 10 has a rotational power of the engine E in the transmission case TM for working through the rear wheels 14, 14 and, in some cases, the traveling output of the front wheels 13, 13 and the PTO shaft 25. It is transmitted as output. Therefore, in the tractor 10, for example, when the clay soil is agitated by the rotary tiller 30, a working output is required and a load is applied to the engine E. Load is applied. The tractor 10 according to the present embodiment is configured such that the output shaft 120 (see FIG. 4) of the motor 119 is attached to the timing transmission mechanism 100 (see FIG. 4). Power can be assisted.

  Next, the control system of the engine E of the tractor 10 according to the present embodiment will be described in detail. FIG. 7 is a principal block diagram of the control system of the tractor 10. The tractor 10 includes an engine controller 201 as a control unit. The engine controller 201 controls the operation of the engine E and is configured to be capable of various automatic controls.

  The engine controller 201 is configured to control the operation of the engine E by reading input signals such as various set values and detection values by various sensors and outputting a control signal. The engine controller 201 includes a CPU (Central Processing Unit) that performs arithmetic processing and control processing, a ROM (Read Only Memory) as a main storage device in which data is stored, a RAM (Random Access Memory), a timer, and an input circuit. And a microcomputer including an output circuit and a power supply circuit.

  Here, an EEPROM 210 (Electrically Erasable Programmable Read Only Memory) in the main memory of the engine controller 201 stores a control program for executing the operation according to the present embodiment, various data, and the like. The data such as these various programs may be stored in an external storage unit and read by the engine controller 201.

  The control of the engine E may be configured to be controlled by an airframe control unit (not shown) included in the tractor 10. The tractor 10 includes a plurality of control units, for example, control units that respectively control the engine E, display the instrument panel 40, control the rotary tiller 30, and the like, and each of them by in-vehicle communication such as CAN (Controller Area Network) communication. It may be configured to be able to communicate with each other. Further, the airframe control unit and the engine controller 201 may cooperate to control the engine E.

  A starter switch 202, an accelerator sensor 203, a rotation sensor 204, and an electromagnetic solenoid of the fuel injection valve 205 are electrically connected to the engine controller 201. The engine controller 201 is electrically connected to various sensors other than the configuration illustrated in FIG.

  The starter switch 202 serving as a starting unit is operated to start the engine E. The accelerator operating tool 206 as a rotation speed setting unit for adjusting the accelerator opening, such as the accelerator lever 50 and the accelerator pedal 54, is configured such that the operation position is detected by the accelerator sensor 203. A rotation sensor 204 as a rotation speed detection unit is provided on the output shaft 120 of the engine E and is configured to detect the rotation speed of the engine E. The fuel injection valve 205 of the injector is configured as a rotation speed changing unit in which fuel is injected into the engine E by opening the valve.

  The starter switch 202 may be a key cylinder type or a push button type. In the tractor 10 according to the present embodiment, when the starter switch 202 is turned on, the engine controller 201 operates the fuel injection valve 205 and transmits a control signal to a starter relay (not shown), and is operated by the starter relay (not shown). The engine E is configured to start by the power of the starter motor.

  In the EEPROM 210 of the engine controller 201, output characteristics corresponding to the rotation speed and torque of the engine E are stored in advance as an output characteristic map M in a map format, for example.

  For example, the engine controller 201 uses the rotation speed of the engine E detected by the rotation sensor 204, the operation position of the accelerator operation tool 206 detected by the accelerator sensor 203, and the output characteristic map M to determine the rotation speed of the engine E. A target fuel injection amount that achieves the target rotational speed is calculated. Based on the result, the engine controller 201 is configured to output a control signal to the electromagnetic solenoid of the fuel injection valve 205 to execute fuel injection control. The fuel injection amount is adjusted by, for example, changing the opening time of the fuel injection valve 205.

  A motor 119 is further electrically connected to the engine controller 201. The motor 119 is configured to be switched between operation and stop by the engine controller 201.

  The engine controller 201 has a load calculation unit 211. The load calculation unit 211 is configured by a program, for example. The load calculation unit 211 is configured to calculate the current load factor of the engine E as a load. Here, the load factor of the engine E according to the present embodiment is the ratio of the actual torque at the present time with respect to the maximum torque (maximum engine load) at a predetermined rotation speed of the engine E. Note that the actual torque at the present time is obtained from the rotational speed of the engine E and the fuel injection amount. For the load factor, a load ratio of the PTO shaft 25 of the rotary tiller 30 may be used.

  The engine controller 201 further includes a determination unit 212. The determination unit 212 is also configured by a program, for example. The determination unit 212 is configured to determine whether or not the engine E is overloaded. Furthermore, the determination unit 212 is configured to determine whether or not the engine E is in the low speed rotation range and the output torque necessary for work is insufficient. The output torque necessary for the work is set as appropriate according to the work machine and the work content.

  The engine E and the motor 119 are controlled by the tractor 10 having the above configuration. Next, a method for controlling the tractor 10 according to the present embodiment will be described in detail. FIG. 8 is a flowchart of a method for controlling the tractor 10.

  First, the engine E is started by operating the starter switch 202 of the tractor 10 (step S1). Then, operation of the tractor 10 and work by the rotary tiller 30 are performed.

  Next, the target rotational speed of the engine E is set in accordance with the amount of operation of the accelerator operating tool 206 by the worker (step S2). On the other hand, the rotation sensor 204 detects the rotation speed of the engine E (step S3). These values are read into the engine controller 201.

  Next, the engine controller 201 calculates a target fuel injection amount (step S4). More specifically, the engine controller 201 first outputs an output characteristic map M according to the engine speed, the target engine speed, and the engine speed and torque stored in the EEPROM 210 in advance. Is read. Next, the engine controller 201 uses these to calculate a target fuel injection amount such that the rotational speed of the engine E becomes the target rotational speed.

  Next, the fuel injection valve 205 changes the fuel injection amount to the engine E so that the rotation speed detected by the rotation sensor 204 becomes the target rotation speed set by the accelerator operating tool 206 (step S5). More specifically, the engine controller 201 outputs a control signal to the electromagnetic solenoid of the fuel injection valve 205 to execute fuel injection control. The fuel injection amount by the fuel injection valve 205 is read into the engine controller 201.

  Next, the load calculation unit 211 calculates the load factor of the engine E at the current time (step S6). As described above, the load factor of the engine E according to the present embodiment is the ratio of the actual torque at the current time with respect to the maximum torque (maximum engine load) at a predetermined rotation speed of the engine E. The actual torque at the present time is obtained from the rotational speed of the engine E and the fuel injection amount.

  The determination unit 212 determines whether or not the engine E is overloaded based on the current load factor of the engine E (step S7).

  Here, an outline of the variation of the load factor of the engine E will be described. FIG. 9 is a schematic diagram illustrating an example of a variation in the load factor P of the engine E. In FIG. 9, the horizontal axis indicates the operation time t [s], and the vertical axis indicates the load factor P [%] of the engine E. In FIG. 9, the lower line is the driving load factor P <b> 1, the work load factor P <b> 2 is between the lower line and the upper line, and the upper line is the load of the engine E as a whole. The rate PT. The load factor P of the engine E being 100% means the rated output of the engine E. Here, the simplest overload determination and control method will be described.

  The tractor 10 requires a traveling output in addition to the working output via the PTO shaft 25. Therefore, when the rated output of the tractor 10 is, for example, 70 horsepower, the working horsepower can use only 60 horsepower, for example. However, the tractor 10 often requires 70 horsepower or 80 horsepower instantaneously during various operations.

  In FIG. 9, for example, a line with a load factor P of 90% is drawn as the overload threshold. Assume that during operation of the tractor 10, for example, the lowering button 72 d of the work implement lifting switch 72 and the tilt manual lever 69 are operated, and the load factor PT of the engine E increases. 9, when the load factor PT of the engine E reaches 90%, the determination unit 212 determines that the engine E is overloaded (step S7; YES).

  On the other hand, as indicated by a point b in FIG. 9, when the load factor PT of the engine E falls below 90%, the determination unit 212 determines that the engine E is not overloaded (step S7; NO).

  Then, as shown in FIG. 8, when it is determined that the engine E is overloaded (step S7; YES), the engine controller 201 controls the motor 119 to operate (step S8). .

  Thus, by operating the motor 119, power is transmitted from the output shaft 120 to the timing transmission mechanism 100 of the engine E, and the power (output) of the engine E can be assisted.

  On the other hand, when it is determined that the engine E is not overloaded (step S7; NO), the determination unit 212 further determines that the engine E is based on the current rotational speed and torque of the engine E. It is determined whether or not the output torque necessary for work is insufficient in the low-speed rotation range (step S9).

Here, FIG. 10 is a schematic diagram showing an example of the output characteristic map M (the rotational speed N of the engine E—the output torque T diagram). In FIG. 10, the horizontal axis indicates the rotational speed N of the engine E, and the vertical axis indicates the output torque T (load). The output characteristic map M shows the maximum output torque Tm at a predetermined engine speed N. The output characteristic map M draws a convex mountain shape, and the maximum output torque Tm becomes maximum when the rotational speed N of the engine E is a predetermined rotational speed Nm, for example, 2000 min ⁻¹ .

  In the present embodiment, the low-speed rotation range Nl of the engine E indicates a region where the rotation speed is lower than the predetermined rotation speed Nm of the engine E in which at least the maximum output torque Tm has a maximum value. As shown in FIG. 10, the maximum output torque Tm decreases in the low speed rotation region Nl. Therefore, when the rotational speed N of the engine E is low, it is easily affected by an increase in the load factor PT of the engine E, and the torque is likely to be reduced.

  Therefore, as shown in FIG. 8, even when it is determined that the engine E is in the low speed rotation region Nl and the output torque T necessary for the work is insufficient (step S9; YES), the engine controller 201 Control is performed to operate the motor 119 (step S8). That is, power up is achieved in the assist mode by the motor 119.

  In FIG. 10, the corrected output torque Ta when the power of the engine E is assisted by the motor 119 in the low speed rotation region Nl is illustrated by a two-dot chain line. For example, the corrected output torque Ta is set to the same value as the maximum output torque Tm at a predetermined rotational speed Nm. In the tractor 10 according to the present embodiment, the operation of the motor 119 is performed when the engine E is in the low speed rotation region Nl and the output torque T necessary for work is insufficient. As a result, the power is transmitted from the output shaft 120 of the motor 119 to the timing transmission mechanism 100 of the engine E, and the tractor 10 outputs the output torque T from the maximum output torque Tm to the corrected output torque Ta as shown in FIG. And the power of the engine E can be assisted.

  On the other hand, when it is not determined that the engine E is in the low speed rotation range Nl and the output torque T necessary for the work is insufficient (step S9; NO), the engine controller 201 stops the motor 119. Control is performed as follows (step S10). Therefore, the motor 119 rotates only when a power-up mode signal that requires assistance from the engine E is received.

  Then, after either the operation of the motor 119 (step S8) or the stop of the motor 119 (step S10) is performed, it is determined whether or not the operation of the tractor 10 is terminated (step S11). .

  If the operation of the tractor 10 is not terminated (step S11; NO), the process returns to step S2. On the other hand, when the operation of the tractor 10 is finished (step S11; YES), the control is finished.

  Normally, as the load factor PT of the engine E increases, the rotational speed N gradually decreases. In this case, the tractor 10 according to the present embodiment is such that the motor 119 assists the engine E so that the rotational speed N does not decrease. That is, the output shaft 120 of the motor 119 rotates to apply torque to the engine E only when power assistance is necessary, and the output is increased, for example, by 10 horsepower or 15 horsepower, thereby avoiding engine stall. . In this way, it is determined whether or not the load factor PT of the engine E has reached a predetermined value, and when the engine E is overloaded, the motor 119 is controlled to operate. According to this method, it is possible to assist the power of the engine E in a timely manner with a simple configuration.

  In the above-described example, the load factor P as the overload threshold is 90%, but the vehicle type of the tractor 10, the output of the engine E, the type of work implement, the type of work, the situation, the weather, etc. It can be changed as appropriate according to the situation. At this time, a threshold adjustment dial (not shown) that can be adjusted by an operator may be provided. Further, in the example described above, the threshold values for the operation and stop of the motor 119 are the same, but these may be different values.

  The effect of the tractor 10 according to the present embodiment is more noticeable as the engine E is larger. This is because the larger the engine E is, the higher the horsepower is applied to the drive gear 116, and the larger motor 119 is attached. However, it is also possible to apply the tractor 10 according to the present embodiment to a small size. For example, even if the output of the engine E is 20 horsepower, for example, assistance of about 10% is possible. On the other hand, if the output of the engine E is 100 horsepower, for example, assistance of about 20 horsepower is possible.

  Next, a modified example of the tractor 10 according to the present embodiment will be described in detail. Note that the description of the same configuration as the above-described embodiment is omitted as appropriate.

  FIG. 11 is a principal block diagram of a control system of the tractor 10 according to a modification. The tractor 10 according to the modification further includes an electromagnetic clutch 221 as a connection / disconnection device that connects / disconnects the timing transmission mechanism 100 of the engine E and the output shaft 220.

  The electromagnetic clutch 221 is electrically connected to the engine controller 201. The electromagnetic clutch 221 is configured such that the engine controller 201 performs switching of power connection and disconnection between the timing transmission mechanism 100 of the engine E and the output shaft 220.

  The connecting / disconnecting device is not limited to the electromagnetic clutch 221 as long as it can connect / disconnect the timing transmission mechanism 100 of the engine E and the output shaft 220. For example, a clutch that operates by hydraulic pressure may be used.

  The engine E and the motor 119 are controlled by the tractor 10 according to the modified example having the above configuration. Next, a method for controlling the tractor 10 according to the present embodiment will be described in detail. FIG. 12 is a flowchart of a method for controlling the tractor 10 according to a modification. The control method according to the modified example is the same as steps S1 to S7 of the control method according to the above-described embodiment. Here, the control method from step S7 will be described in detail.

  As described above, the determination unit 212 determines whether or not the engine E is overloaded based on the current load factor PT of the engine E (step S7). 9, when the load factor PT of the engine E reaches 90%, the determination unit 212 determines that the engine E is overloaded (step S7; YES).

  Then, as shown in FIG. 12, in the method according to the modified example, when it is determined that the engine E is overloaded (step S7; YES), the power connection between the motor 119 and the engine E is established. Is performed (step S12). More specifically, the engine controller 201 transmits a control signal so as to connect the electromagnetic clutch 221. When the electromagnetic clutch 221 is connected, the timing transmission mechanism 100 of the engine E is connected to the output shaft 220 of the motor 119, and the power between them is transmitted.

  After the power is connected, the engine controller 201 controls the motor 119 to operate (step S8), and thereafter, the control method is the same as in the above-described embodiment.

  On the other hand, as indicated by a point b in FIG. 9, when the load factor PT of the engine E falls below 90%, the determination unit 212 determines that the engine E is not overloaded (step S7; NO).

  Then, as shown in FIG. 12, in the method according to the modified example, when it is determined that the engine E is not overloaded (step S7; NO), the power of the motor 119 and the engine E is cut off. Is performed (step S13). More specifically, the engine controller 201 transmits a control signal so that the electromagnetic clutch 221 is disengaged. When the electromagnetic clutch 221 is disengaged, the timing transmission mechanism 100 of the engine E and the output shaft 220 of the motor 119 are disconnected, and the power therebetween is not transmitted.

  After the power is cut off, the engine controller 201 controls to stop the motor 119 (step S10), and thereafter, the control method is the same as that in the above-described embodiment.

  Thus, in the control method according to the modification, when the engine controller 201 determines that the engine E is not overloaded, the power from the timing transmission mechanism 100 to the output shaft 220 is cut off by the electromagnetic clutch 221. To do. Although the motor 119 according to the present embodiment does not generate power and the motor 119 itself is not loaded, the idling torque of the motor 119 is not applied to the timing transmission mechanism 100 of the engine E. E load can be further reduced. And deterioration of the motor 119 can be prevented.

  In addition to determining whether or not the engine E is overloaded, after determining whether or not the engine E is in the low speed rotation range Nl and the output torque T necessary for work is insufficient, Control may be performed so as to connect / disconnect power from the timing transmission mechanism 100 to the output shaft 220. As a result, the same effect as described above can be obtained even when the engine E is in the low speed rotation range Nl and the output torque T required for work is insufficient.

  As described above, in the present embodiment, in the tractor 10 including the engine E and the rotary tiller 30 attached, the motor 119 in which the output shafts 120 and 220 are attached to the timing transmission mechanism 100 provided in the engine E, and the engine An engine controller 201 that calculates the load of E and controls the operation of the motor 119. When the determination unit 212 of the engine controller 201 determines that an overload has occurred in the engine E, or the engine E is slow The motor 119 is configured to operate when it is determined that the output torque T necessary for work is insufficient in the rotation range Nl. Thus, it is possible to provide the tractor 10 that can assist the power of the engine E in a timely manner with a simple configuration.

  Further, in the tractor 10 according to the present embodiment, the timing transmission mechanism 100 configured by the crank gear 105, the idle gear 107 that meshes with the crank gear 105, and the cam gear 109 that meshes with the idle gear 107 is driven to engage with the cam gear 109. A gear 116 is further provided, and the output shafts 120 and 220 are attached to the drive gear 116. Thus, it is possible to provide the tractor 10 that can reliably assist the power of the engine E in a timely manner with a simple configuration.

  The work vehicle of the present invention is not limited to the combination of the tractor 10 and the rotary tiller 30. For example, the work vehicle such as a transplanter, a seedling planting device, a construction machine, and an attachment is used. The present invention can be applied to any work vehicle in which the load of the engine E fluctuates due to the combination of the machine and the work machine and the change of the work state by the work machine.

10 Tractor (work vehicle)
30 Rotary tillage device (work machine)
100 Timing transmission mechanism 103 Crankshaft 105 Crank gear 107 Idle gear 109 Cam gear 116 Drive gear 119 Motor 120, 220 Output shaft 121 Spline shaft 201 Engine controller (control unit)
221 Electromagnetic clutch (connecting / disconnecting device)
E engine

Claims (5)

In a work vehicle equipped with an engine and equipped with a work implement
A motor having an output shaft attached to a timing transmission mechanism provided in the engine;
A controller for calculating the load of the engine and controlling the operation of the motor;
When the control unit determines that the engine is overloaded, or when the engine is in a low speed rotation range and determines that the output torque necessary for work is insufficient, the motor is operated. A work vehicle characterized by being configured to perform. The timing transmission mechanism constituted by a crank gear, an idle gear meshing with the crank gear, and a cam gear meshing with the idle gear,
A drive gear meshing with the cam gear;
The work vehicle according to claim 1, wherein the output shaft is attached to the drive gear. The work vehicle according to claim 2, wherein the output shaft extends in parallel with a crankshaft to which the crank gear is attached, and the motor is disposed on a side of the engine. The work vehicle according to any one of claims 1 to 3, wherein the output shaft is configured by a spline shaft. The work vehicle is
A connecting / disconnecting device for connecting / disconnecting the timing transmission mechanism and the output shaft;
When the control unit determines that the engine is not overloaded, the controller is configured to cut off power from the timing transmission mechanism to the output shaft by the connecting / disconnecting device. The work vehicle according to any one of claims 1 to 4.

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