JP6615817B2 - Tracked tractor - Google Patents

Description

  The present invention relates to a technique for securing the amount of hydraulic oil in a crawler tractor provided with a crawler type traveling device.

  Patent Document 1 discloses a configuration of a crawler tractor including a pair of left and right crawler type traveling devices. Here, a turning method that makes use of the speed difference between the left and right crawlers is adopted, and a hydraulic continuously variable transmission for turning is mounted. For this reason, the hydraulic oil used as the lubricating oil is stored in the transmission case, and a dedicated hydraulic oil tank connected to the transmission case is provided to ensure the necessary amount of hydraulic oil.

Japanese Patent No. 4694717

  A conventional crawler tractor equipped with a crawler type traveling device was designed based on a design concept exclusively for crawler tractors. From the viewpoint of reducing the manufacturing cost of the entire tractor including wheel tractors and crawler tractors, the frame structure It is required to share the same with other types of tractors, or to share the parts with each other. That is, there is an increasing demand for manufacturing a crawler tractor based on the structure of a wheel tractor with a large number of productions.

  In particular, the required amount of hydraulic oil is secured while following the body layout of the wheel tractor in that a predetermined amount of hydraulic oil must be secured for the hydraulic continuously variable transmission for turning of the crawler type traveling device. However, it is difficult to dispose the hydraulic oil tank while taking into consideration prevention of air suction when the aircraft is tilted. Furthermore, since medium-sized tractors are being made more compact, there is no extra space, and it is difficult to newly arrange a hydraulic oil tank having a desired capacity.

  A crawler tractor comprising a pair of left and right crawler type traveling devices, and a hydraulic piping device that connects and circulates a mission case provided at the rear of the aircraft and a turning mission case provided at the front of the aircraft along the longitudinal direction of the aircraft At the same time, the intermediate part of the hydraulic piping device in the longitudinal direction of the machine body is a tank part constituted by a pipe having a larger diameter than the front side piping part and the rear side piping part, and the hydraulic oil is stored in the tank part.

  The said hydraulic piping apparatus is arrange | positioned in the space between an airframe frame and the track frame of a crawler type traveling apparatus in the left-right direction of an airframe.

  A suction filter was built in the tank part.

  According to the present invention, it is not necessary to newly arrange a hydraulic oil tank, and it is possible to realize a crawler tractor having a substantially same body layout as another type of tractor such as a wheel tractor.

Side view of crawler tractor A perspective view showing a frame structure of a crawler tractor A perspective view showing a frame structure of a crawler tractor Plan view showing the hydraulic piping system Equalizer perspective view Equalizer perspective view Rear view showing rear housing Rear housing perspective view Perspective view showing the axle case Diagram showing relationship between engine and turning mission case Skeleton diagram showing power transmission path of crawler tractor Diagram showing the configuration of the deceleration shaft End view showing the internal transmission structure of the turning mission case A diagram showing a part of the assembly of a turning mission case Diagram showing how power is taken into the turning mission case Diagram showing brake link structure Crawler tractor hydraulic circuit diagram

  The crawler tractor 1 will be described with reference to FIGS. 1 to 4. The crawler tractor 1 includes a pair of left and right crawler type traveling devices 2, a body frame 3 supported by the crawler type traveling device 2, an engine 4 and a mission case 5 mounted on the body frame 3, a mission case 6 for turning, A hood 7 covering the engine 4, a cabin 8 provided at the rear of the hood 7, and the like. The mission case 5 is disposed at the rear end of the machine body, the PTO shaft 9 protrudes from the rear surface of the mission case 5, and power is transmitted to the work machine attached to the rear of the tractor via the PTO shaft 9. The turning mission case 6 is disposed at the front end of the airframe.

  In the crawler tractor 1, the power of the engine 4 is transmitted to the mission case 5, and after being shifted by a straight-forward HST attached to the mission case 5, the crawler tractor 1 is transferred to the turning mission case 6 via a drive shaft extending in the longitudinal direction of the machine body. Power is transmitted. Then, the motive power input by the turning HST attached to the turning mission case 6 is shifted to output different rotational speeds to the left and right crawler type traveling devices 2. In this way, the crawler tractor 1 employs a turning method that uses the difference in speed between the left and right crawler type traveling devices 2 during turning (details will be described later).

  The body frame 3 has a pair of left and right plates extending in the longitudinal direction of the body and a reinforcing body that connects the left and right plates. The engine 4 is supported on the front frame 3a constituting the front part of the body frame 3, and the mission case 5 is supported on the rear frame 3b constituting the rear part. The mission case 5 is fixed between the left and right plates of the body frame 3, and the body frame 3 and the mission case 5 form a highly rigid frame structure. Thus, the fuselage frame 3 has a split structure in which the front frame 3a and the rear frame 3b are connected to each other in the front-rear direction, and the engine 4 is fixed to the front frame 3a and the transmission case 5 is fixed to the rear frame 3b. The assemblability of the frame structure is improved.

  The crawler type traveling device 2 is provided as a pair on the left and right sides of the machine body. The crawler type traveling device 2 includes a track frame 21, a drive sprocket 22, a tension roller 23, an idler wheel 24, a guide roller 25, a crawler belt 26, and the like. The track frame 21 is provided outside the body frame 3. The track frame 21 extends in the longitudinal direction of the machine body, the front portions of the left and right track frames 21 are connected by a front beam 27, and the rear portions thereof are connected by a rear beam 30.

  The front end of the track frame 21 is fixed to an axle case 31 provided on the side of the turning mission case 6, and a tension frame 28 that is extendable in the front-rear direction is connected to the rear end. A tension roller 23 is rotatably supported on the tension frame 28. The drive sprocket 23 is fixed to an output shaft that protrudes from the axle case 31. The idler wheels 24 are provided at two locations, a front portion and a rear portion of the track frame 21, and are respectively rotatably supported on the front and rear of an equalizer frame 29 that is supported on the lower portion of the track frame 21 so as to be swingable back and forth. Yes. The guide roller 25 is rotatably provided at the upper part of the front and rear halfway part of the track frame 21. The crawler belt 26 is wound around the drive sprocket 22, the tension roller 23, the idler wheel 24, and the guide roller 25.

  Lubricating oil stored in the transmission case 5 is used as hydraulic oil for the straight traveling HST and the turning HST. Between the transmission case 5 and the turning transmission case 6, hydraulic oil is circulated through the hydraulic piping device 40. The system of the hydraulic piping device 40 includes a hydraulic pump that feeds hydraulic oil.

  The hydraulic piping device 40 is a hydraulic piping structure that connects the mission case 5 at the rear of the machine body and the turning mission case 6 at the front of the machine body, and is provided along the longitudinal direction of the crawler tractor 1. The hydraulic piping device 40 includes a feed side suction pipe 41 arranged on the left and right sides of the machine body from the mission case 5 (right side in the present embodiment), and a return side reduction pipe 51 arranged on the other side. The suction pipe 41 and the reduction pipe 51 are hydraulic pipes that connect and connect the transmission case 5 and the turning mission case 6 (and the turning HST), respectively. The suction pipe 41 and the reduction pipe 51 are arranged between the machine frame 3 and the track frame 21 in the left-right direction of the machine body, and are arranged above the track frame 21 in the machine body vertical direction.

  The intermediate part of the suction pipe 41 in the longitudinal direction of the machine body is configured as a tank part 42 constituted by a pipe having a larger diameter than other parts of the pipe (front pipe part and rear pipe part). Similarly, the intermediate part of the reduction pipe 51 in the longitudinal direction of the machine body is configured as a tank part 52 constituted by a pipe having a larger diameter than other parts of the pipe (the front pipe part and the rear pipe part). In other words, in the hydraulic piping device 40, a part of the hydraulic piping connecting the transmission case 5 and the turning mission case 6 is enlarged in diameter, and the capacity is partially increased and used as a hydraulic oil tank.

  Suction piping 41 includes rear piping 43 connected to mission case 5, front piping 44 connected to turning HST 93, and tank portion 42. The rear side piping 43 and the front side piping 44 are configured by pipes having a smaller diameter than the tank portion 42. The front end of the tank portion 42 is fixed on the front beam 27 via the stay 45. The rear end of the tank portion 42 is fixed to the rear frame 3b via a bracket 46.

  The reduction pipe 51 includes a front pipe 53 connected to the turning HST 93, a rear pipe 54 connected to a rear housing 70 attached to the transmission case 5, and a tank unit 52. The front side pipe 53 and the rear side pipe 54 are constituted by pipes having a smaller diameter than the tank portion 52. The front end of the tank portion 52 is fixed on the front beam 27 via the stay 55. The rear end of the tank portion 52 is fixed to the rear frame 3b via a bracket 56. The tank part 42 of the suction pipe 41 and the tank part 52 of the reduction pipe 51 are arranged at symmetrical positions around the center in the longitudinal direction of the machine body, and their fixed positions are also arranged at symmetrical positions.

  As described above, the hydraulic piping device 40 is configured to include the suction pipe 41 having the tank portion 42 in the middle part of the front and rear, and the reduction pipe 51 having the tank part 52 in the middle part of the front and rear. 52 is made to function as a hydraulic oil tank. Thereby, in the crawler tractor 1 including the straight HST and the turning HST, the amount of hydraulic oil necessary for stable operation of the hydraulic continuously variable transmission is ensured. By providing a hydraulic oil tank function by enlarging part of the hydraulic piping, it is not necessary to provide a separate hydraulic oil tank when installing the turning HST. Moreover, since it is not necessary to prepare a space for installing the hydraulic oil tank, it can be easily adopted regardless of the size of the tractor.

  Therefore, it is possible to change as little as possible from the body layout of the wheel tractor that does not have a crawler type traveling device (addition of a hydraulic piping device 40 extending in the longitudinal direction of the body in the space between the body frame 3 and the track frame 21). Therefore, it is possible to design the machine layout of the crawler tractor 1 provided with the crawler type traveling device 2. And it becomes possible to aim at commonality of parts by reducing a difference part. For example, when designing the body layout of the crawler tractor 1 from the body layout of the wheel tractor, the configuration of the crawler type traveling device 2 is added. The change point at that time is between the body frame 3 and the track frame 21. It is only necessary to arrange the hydraulic piping device 40 in the surplus space. That is, it is possible to effectively utilize the surplus space generated when the crawler tractor is manufactured, and to produce a specific effect that it is not necessary to change other parts.

  Furthermore, since the tank portions 42 and 52 as hydraulic oil tanks are constituted by large-diameter pipes, the surface area in contact with air can be made larger than that of a normal pipe portion. Therefore, when hydraulic oil circulates, There is a specific effect that a reduction in temperature can be expected.

  A suction filter 47 is built in the tank portion 42 of the suction pipe 41. That is, the suction filter 47 is provided on the take-out side of the downstream end portion of the tank portion 42 configured as a large-diameter pipe. Since the tank part 42 as a hydraulic oil tank of this embodiment is a large diameter pipe, the suction filter 47 can be provided on the same axis of the circulation path. Therefore, unlike a conventional rectangular parallelepiped container type hydraulic oil tank, it is not necessary to provide a suction filter outside, and space is not compressed. In addition, since the tank portion 42 is partially formed as a large-diameter pipe, the hydraulic piping can be easily removed, so that the maintenance performance of the suction filter 47 can be improved.

  And, by using part of the hydraulic piping extending in the longitudinal direction of the fuselage as the tank parts 42 and 52 as the hydraulic oil tank, it is highly robust against the tilt of the fuselage and it is possible to reduce air suction into the hydraulic oil It is. Similarly, a return filter can be built in the tank portion 52 of the reduction pipe 51.

  As shown in FIGS. 5 and 6, a reinforcing plate 61 is provided on the equalizer 60 including the idler wheel 24 and the equalizer frame 29. The equalizer 60 is configured to be swingable in the longitudinal direction of the machine body about the rotation support shaft 62, but the swinging range thereof is restricted by the reinforcing plate 61 coming into contact with the track frame 21.

  In this way, by bending the front and rear ends of the plate for reinforcing the equalizer 60 to form the contact surface with the track frame 21, the reinforcing plate 61 can also be used as a rotation restriction stopper. . Conventionally, a shaft has been provided for a stopper, but the shaft is not necessary because the reinforcing plate 61 also serves as a stopper.

  As shown in FIGS. 7 and 8, rear housings 70 are attached to the left and right sides of the mission case 5. In the wheel tractor, the crawler tractor 1 is provided with a rear housing 70 at a position corresponding to the place where the rear axle case is provided. The interior of the rear housing 70 communicates with the transmission case 5, and the lubricating oil stored in the transmission case 5 can be distributed to the rear housing 70. In other words, by installing the rear housing 70, the amount of oil that can be stored in the transmission case 5 and the rear housing 70 can be increased.

  An oil inspection window 71 is provided on a part of the rear surface of the rear housing 70 on the left and right sides (right side in the present embodiment). The oil inspection window 71 is provided in the middle part of the rear housing 70 in the vertical direction, and is provided at a position where it is possible to confirm a decrease in the oil level of the hydraulic oil stored in the transmission case 5 and the rear housing 70. By checking the amount of oil in the mission case 5 through the oil inspection window 71, it is possible to secure the amount of oil necessary for each hydraulic system.

  The mission case 5 and the rear housing 70 are each fixed by bolt fastening or the like. The rear housing 70 is fixed to the rear beam 30 by bolt fastening or the like. That is, the mission case 5 is supported by the rear beam 30 via the rear housings 70 and 70. The rear housing 70 supports the cabin 8 and the fuel tank 72. The fuel tank 72 is attached to the rear housing 70 via a support stay 73.

  As described above, the rear housing 70 provided on both sides of the transmission case 5 of the crawler tractor 1 has a function as a hydraulic oil tank, a calibration function by the oil detection window 71, a function to support the cabin 8 and the fuel tank 72, and the like. By attaching various functions, it is not necessary to separately provide each member, and the number of parts can be reduced.

  As shown in FIG. 9, the axle cases 31 and 40 attached to the left and right of the mission case 5 have the same configuration. Although it is necessary to provide a drain hole for maintenance at the lower part of the axle case, the axle case 31 of the present embodiment has a symmetrical shape, and a drain hole 41 is provided symmetrically at the lower end of the case. By using the drain hole 41 located on the lower side when assembled on the left side as a drain hole for maintenance, the parts are shared.

  As described above, by adopting the same components for the left and right axle cases 31, the number of component types can be reduced, manufacturing costs can be reduced, and component management costs can be reduced. Further, it is possible to prevent erroneous assembly due to similar parts that may occur when different parts are used on the left and right.

  As shown in FIG. 10, the turning mission case 6 is disposed in front of and below the engine 4, and the upper surface of the turning mission case 6 is formed to be inclined downward from the front to the rear. As a result, the wind from the front of the turning mission case 6 flows along the upper surface, whereby the wind can be circulated toward the engine oil pan 75 located at the lower part of the engine 4. Engine oil can be cooled.

  Thus, by making the outer shape of the turning mission case 6 into consideration of the flow of wind, it is not necessary to separately install a wind direction plate, and the number of parts can be reduced. In addition, the circulation of the wind around the engine 4 can be improved with a simple device.

  Next, the power transmission configuration of the crawler tractor 1 will be described with reference to FIG.

  Power is transmitted from the output shaft 80 projecting rearward from the engine 4 to the pump shaft 81 and the PTO clutch 82 in the mission case 5. The PTO clutch 82 is shifted by a PTO transmission 83 and power is transmitted to the PTO shaft 9. A straight HST 84 is disposed on the pump shaft 81. The motor shaft 85 of the rectilinear HST 84 is formed in a pipe shape and disposed on the pump shaft 81. Power is transmitted from the motor shaft 85 to the transmission shaft 88 via a transmission shaft 87 provided with a forward / reverse switching clutch 86. On the transmission shaft 88, first-speed, second-speed and third-speed clutches are respectively provided. The output from the transmission shaft 88 is transmitted to the input bevel shaft 91 of the turning mission case 6 via the transmission shaft and transmission gear.

  Power is transmitted from the front output shaft 92 protruding forward from the engine 4 to the pump shaft 94 of the turning HST 93. The turning HST 93 is attached to the front surface of the turning mission case 6. The movable swash plate of the turning HST 93 is linked to the steering handle in the cabin 8. The motor shaft 95 of the turning HST 93 extends into the turning mission case 6, and a bevel gear 96 is fixed to the tip thereof. The bevel gear 96 meshes with the left and right bevel gears 97 and 97, and from the motor shaft 95, the normal rotation power is transmitted to one of them and the reverse rotation power is transmitted to the other. Power is transmitted from the bevel gears 97 to the carriers 99 of the left and right planetary gear mechanisms 98 that form a forced differential.

  Power is transmitted from the input bevel shaft 91 to the differential input shaft 100 of the planetary gear mechanism 98. A sun gear 101 of the planetary gear mechanism 98 is fixed to the end of the differential input shaft 100, and the sun gear 101 is engaged with the planetary gear 102. The planetary gear 102 is rotatably supported on the carrier shaft of the carrier 99. It is transmitted from the planetary gear mechanism 98 to the drive shaft 104 of the drive sprocket 22 via the reduction shaft 103.

  When the steering handle is in the straight traveling state, the turning HST 93 is neutral, the motor shaft 95 is not rotated, the output after being shifted by the transmission case 5 is transmitted to the drive shaft 104, and has the same number of rotations as the left and right. Go straight. When the steering handle is rotated to the left or right, the movable swash plate of the turning HST 93 is tilted according to the rotation direction and the rotation angle, and the output rotation direction and the rotation speed corresponding to the tilt are output to the motor shaft 95. Then, forward rotation from the motor shaft 95 to the left and right bevel gears 97 is applied to the planetary gear mechanism 98 to increase the speed, and the other planetary gear mechanism 98 is subjected to reverse rotation to be decelerated. In this way, the crawler tractor 1 adopts the turning method by changing the output to the left and right crawler type traveling devices 2 according to the rotation of the steering handle.

  As shown in FIG. 12, the speed reduction shaft 103 in the axle case 31 is not divided in the middle portion but is configured as a single shaft. The speed reduction shaft 103 is a final speed reduction shaft that outputs the rotational power shifted in the turning mission case 6 to the input shaft of the drive sprocket 22. In this way, by integrating the speed reduction shaft 103 that has conventionally been divided, the number of assembling steps can be reduced and the productivity can be improved. In addition, unlike the divided structure, the number of bearings that support the reduction shaft 103 can be reduced, and the number of parts can be reduced.

  As shown in FIGS. 11 and 13, the friction plate 105 of the parking brake is not disposed on the input bevel shaft 91 but is disposed on the brake shaft 106 provided separately, and the brake is applied via the brake shaft 106. Adopted. A brake gear 107 is fixed to the brake shaft 106. The brake gear 107 meshes with the brake gear 108 on the input bevel shaft 91 side. This is a mechanism for stopping the rotation of the input bevel shaft 91 via the brake gears 107 and 108 by stopping the rotation of the brake shaft 106 by applying the friction plate 105.

  As described above, by providing the parking brake mechanism at a position separated from the input bevel shaft 91 by one axis, it is possible to give a margin to the space around the input bevel shaft 91. In addition, since the drive shaft serving as the output shaft from the mission case 5 and the input bevel shaft 91 can be arranged coaxially, it is possible to employ a straight type drive shaft.

  As shown in FIG. 14, as a parking brake mechanism, the turning mission case 6 after the friction plate 105, the brake shaft 106, and the brake gear 107 are subassembled and the input bevel shaft 91 and the brake gear 108 are assembled. Assembling performance can be improved.

  Further, as shown in the upper diagram of FIG. 15, as a method of capturing power into the turning mission case 6, a method of directly inputting to the bevel gear 109 from the input bevel shaft 91 and transmitting it to the differential input shaft 100, and FIG. As shown in the figure below, by preparing two types of input from the brake shaft 106 to the bevel gear 110 via the brake gears 107 and 108 and the input bevel shaft 91, depending on the size of the crawler tractor 1, the type of tractor, etc. It becomes possible to change to the occasion. In this manner, by preparing a plurality of methods for taking in power to the turning mission case 6, it is possible to improve the diversion of the mission case having a high generation cost at the time of a new work, and to reduce the cost.

  As shown in FIG. 16, a universal joint 112 is connected to a camshaft 111 for operating a parking brake, an arm 113 for inputting a torque to the camshaft 111 by rotating the universal joint 112 is provided. The arm 113 is connected to the universal joint 112 via a rotating piece 114. The arm 113 extends into the cabin 8 and is connected to a brake pedal 116 in the cabin 8 via a link mechanism 115. When the brake pedal 116 is pushed in, the link mechanism 115 rotates so as to lift the arm 113 upward, and the rotating piece 114 rotates clockwise as the arm 113 moves. Then, the universal joint 112 rotates clockwise, and the cam shaft 111 rotates in the same direction. In this manner, the operation of the brake pedal 116 becomes torque input via the arm 113 and is transmitted to the universal joint 112 and the cam shaft 111.

As described above, the arm 113 is connected via the universal joint 112 instead of directly extending the arm from the camshaft, so that it is not necessary to provide a space around the camshaft 111 and the degree of freedom in layout is ensured. be able to.

  Next, the hydraulic circuit of the crawler tractor 1 will be described with reference to FIG.

  Lubricating oil stored in the mission case 5 is used as hydraulic oil for a straight traveling HST 84, a turning HST 93, a work implement lifting device, a hydraulic clutch, and the like. Power from the rear output shaft 80 of the engine 4 drives a hydraulic pump 120 that pumps hydraulic oil to the lifting device and a hydraulic pump 121 that pumps hydraulic oil to the straight HST 84 and the PTO clutch 82. The hydraulic pump 122 that pumps hydraulic oil to the turning HST 93 is driven by the power from the front output shaft 92 of the engine 4. As described above, the hydraulic piping device 40 is provided between the mission case 5 and the turning mission case 6. By driving the hydraulic pump 122, the rear piping 43, the tank portion 42, It is supplied to the turning HST 93 through the suction pipe 41 including the front pipe 44. And it returns to mission case 5 through reduction piping 51 including front side piping 53, tank part 52, and rear side piping 54 from turning HST93.

  1: Crawler tractor, 2: Crawler type traveling device, 3: Airframe frame, 5: Mission case, 6: Turning mission case, 21: Track frame, 40: Hydraulic piping device, 41: Suction piping, 42: Tank section, 43: Rear piping, 44: Front piping, 47: Suction filter, 51: Reduction piping, 52: Tank section, 53: Front piping, 54: Rear piping

Claims (3)

A crawler tractor including a pair of left and right crawler type traveling devices,
A hydraulic piping device that connects and circulates a mission case provided at the rear of the aircraft and a turning mission case provided at the front of the aircraft is provided along the longitudinal direction of the aircraft,
The machine body longitudinal direction intermediate portion of the hydraulic piping device is a tank portion configured by a pipe having a larger diameter than the front side piping portion and the rear side piping portion, and the hydraulic oil is stored in the tank portion. Crawler tractor to do.   2. The crawler tractor according to claim 1, wherein the hydraulic piping device is disposed in a space between the body frame and a track frame of the crawler type traveling device in the left-right direction of the body.   The crawler tractor according to claim 1, wherein a suction filter is built in the tank portion.

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