JP2008073012A - Hydraulic oil reduction structure for work vehicles - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively reduce cost by rationally improving a hydraulic oil reduction structure.
SOLUTION: A return oil path 34 from another hydraulic actuator C is connected to a return oil path 25 extending from a hydraulic actuator A to a hydraulic oil tank B.
[Selection] Figure 4

Description

  The present invention relates to a hydraulic oil reduction structure for a work vehicle.

  As a working oil reduction structure of a work vehicle, a lifting device comprising a hydraulic cylinder for raising and lowering a working device that uses lubricating oil in a mission case (hydraulic oil tank) as a working oil, an electromagnetic control valve that controls its operation, etc. There is a configuration in which return oil from a hydraulic actuator is returned to the mission case via a dedicated return oil passage extending from the electromagnetic control valve to the mission case (see, for example, Patent Document 1).

  In addition, the return oil from the hydrostatic continuously variable transmission (hydraulic actuator) that uses the lubricating oil in the mission case (hydraulic oil tank) as the hydraulic oil is used for the exclusive use from the hydrostatic continuously variable transmission to the mission case. There is one configured to return to the mission case via a hydraulic return pipe (return oil passage) (see, for example, Patent Document 2).

Further, there is a configuration in which the return oil from the power steering device (hydraulic operation device) is returned to the tank via a dedicated drain oil passage (return oil passage) extending from the power steering device to the tank (hydraulic oil tank). (For example, refer to Patent Document 3).
JP 2004-73029 A JP 2003-25859 A Japanese Patent Laid-Open No. 10-35519

  According to the above configuration, the return oil from each hydraulic actuator is returned to the hydraulic oil tank via a dedicated return oil passage extending to each hydraulic actuator and hydraulic oil tank. It is necessary to form in the oil tank the same number of connection ports as the number of hydraulic actuators connected to the return oil passage. This complicates the shape of the hydraulic oil tank and increases the cost.

  Therefore, by returning the return oil from some hydraulic actuators to the hydraulic oil tank through the breather that is originally installed in the hydraulic oil tank, the number of connection ports formed in the hydraulic oil tank can be reduced. In this case, although the shape of the hydraulic oil tank can be simplified, it is necessary to apply improvements to improve the sealing performance of the breather by applying hydraulic pressure to the breather. As a result, there is room for improvement in cost reduction.

  An object of the present invention is to provide a rational improvement to the hydraulic oil reduction structure so that the cost can be effectively reduced.

  In order to achieve the above object, in the invention according to claim 1 of the present invention, a return oil path from another hydraulic actuator is connected to a return oil path extending from the hydraulic actuator to the hydraulic oil tank. It is characterized by that.

  According to this characteristic configuration, the number of connection ports formed in the hydraulic oil tank can be reduced by the number of return oil paths from other hydraulic actuators connected to the return hydraulic path of the hydraulic actuator, and the hydraulic oil tank The shape of can be simplified.

  In addition, since the return oil passage of the hydraulic actuator is more hydraulic than originally and is configured to have a high sealing performance, it is necessary to make new improvements to improve the sealing performance. There is no.

  Therefore, the hydraulic oil reduction structure can be improved rationally, and the cost can be effectively reduced.

  The invention according to claim 2 of the present invention is characterized in that, in the invention according to claim 1, the other hydraulic operating device is a selection target device whose equipment is selected according to specifications. To do.

  According to this characteristic configuration, for example, when the other hydraulic operation device is a power steering device that assists the steering operation, the specification equipped with a hydraulic power steering device (hydraulic operation device), electric power steering A common hydraulic oil tank can be used regardless of the specification equipped with the device and the specification not equipped with the power steering device.

  When the other hydraulic actuator is a continuously variable transmission, a specification equipped with a hydraulic continuously variable transmission (hydraulic actuator), a specification equipped with a belt type continuously variable transmission, and a gear type Regardless of the specifications equipped with a transmission, etc., a common hydraulic oil tank can be used.

  If the other hydraulic actuator is a rolling device that drives a work device that is connected to the traveling vehicle body so as to be able to roll, a specification equipped with a hydraulic rolling device (hydraulic actuator), an electric rolling device A common hydraulic oil tank can be used regardless of the specifications equipped with the above and the specifications not equipped with a rolling device.

  Therefore, a common hydraulic oil tank can be used regardless of the specifications of the work vehicle, and costs can be reduced compared to the case where a plurality of hydraulic oil tanks corresponding to each specification are prepared.

  According to a third aspect of the present invention, in the invention according to the first or second aspect, the return oil path from the hydraulic actuator is directed from the hydraulic actuator to the hydraulic oil tank. An extended pipe member and a joint member that connects an extended end portion of the pipe member to the hydraulic oil tank, and a return oil path from the other hydraulic actuator is connected to the joint member. It is characterized by being.

  According to this characteristic configuration, when the number of return oil passages from other hydraulic actuators connected to the return hydraulic passages of the hydraulic actuators differs depending on the specifications of the work vehicle, it is only necessary to replace the joint members and replace the pipes. It is possible to cope easily without adding improvements to the members and the hydraulic oil tank.

  Therefore, it is possible to improve the workability when forming the return oil passage according to the specifications of the work vehicle.

  FIG. 1 shows an overall side view of a riding type rice transplanter, which is an example of a work vehicle. This rice transplanter operates an elevating device configured with a hydraulic cylinder 2 or the like at the rear of a traveling vehicle body 1. In this way, the seedling planting device 4 is connected to be able to be driven up and down via a link mechanism 3 that is driven to swing in the vertical direction.

  The traveling vehicle body 1 includes a hydrostatic continuously variable transmission 8 (hydraulic actuator A of the hydraulic actuator A) provided with power from an engine 6 mounted on an anti-vibration front frame 5 as a belt tension main clutch 7 and a main transmission. An example), and a gear-type transmission (not shown) built in the transmission case 9 as an auxiliary transmission, and the like, and is configured to be a four-wheel drive type that transmits to a pair of left and right front wheels 10 and rear wheels 11. Yes.

  A front cover 12 that covers the engine 6 and the like from above is disposed at the front center of the traveling vehicle body 1, and a riding operation unit 13 is formed at the upper part of the traveling vehicle body 1.

  A step 14 made of sheet metal is laid in the boarding operation unit 13, and a main transmission operation system (not shown) is connected to the steering wheel 16, which is linked to the left and right front wheels 10 via the steering operation system 15, and the continuously variable transmission 8. The main transmission lever 17 is linked via a transmission, the auxiliary transmission lever 18 is linked to a transmission via a sub-transmission operating system (not shown), and the lifting / lowering apparatus is linked via a lifting / lowering operation system (not shown). The lift lever 19 and the driver's seat 20 are provided.

  The seedling planting device 4 transmits a working power from a work transmission system (not shown) built in the transmission case 9 to the power distribution mechanism 21 so that a seedling mounting table on which a plurality of mat-like seedlings are placed. A plurality of crank arm-type planting mechanisms 23 arranged side by side at regular intervals in the left-right direction are arranged to plant planted seedlings from the lower end of the seedling stage 22. The mat-like seedlings are taken out each time a fixed amount is taken out and is driven to swing so as to be planted in the mud portion of the field that has been leveled by a plurality of leveling floats 24 and the seedling stage 22 reaches the left and right stroke ends. A plurality of seedlings are planted by being vertically fed toward the lower end of 22 at a predetermined pitch.

  Although not shown, in the lifting device, the control valve controls the flow of hydraulic oil pumped by the hydraulic pump based on the swinging operation of the lifting lever 19, and the lifting / lowering hydraulic cylinder 2 (FIG. 1). It is configured to drive the seedling planting device 4 up and down by extending and contracting (see).

  The lifting lever is linked to a planting clutch provided in the work transmission system via a planting operation system, and the operation state of the seedling planting device 4 can be switched by the swinging operation.

  The hydraulic pump is driven by the power from the engine 6 to pump the lubricating oil stored in the transmission case 9 toward the control valve as hydraulic oil. Return oil from the lifting device is returned to the mission case 9 via a dedicated return oil passage. That is, the mission case 9 is also used as the hydraulic oil tank B.

  The continuously variable transmission 8 performs a stepless speed change operation by changing the swash plate angle of the variable displacement pump based on the swing operation of the main speed change lever 17 and increasing or decreasing the output rotational speed of the constant capacity motor. In addition, it is configured to perform forward / reverse switching by switching the rotation direction of the constant capacity motor.

  As shown in FIGS. 2 to 4, the return oil from the continuously variable transmission 8 is returned to the mission case 9 via a dedicated return oil passage 25. The return oil passage 25 is formed by a pipe member 26 extending from the continuously variable transmission 8 toward the transmission case 9 and a joint member 27 that connects the extended end of the pipe member 26 to the transmission case 9. Yes.

  A rubber hose that can be elastically deformed is used for the pipe member 26. The joint member 27 includes a connecting portion 27A to which the extending end portion of the pipe member 26 is connected, and an insertion portion 27B that is removably inserted into the mission case 9 from an oil supply port 9A formed in the upper portion of the mission case 9. An O-ring 28 is provided at the upper end of the insertion portion 27B so as to prevent oil leakage from the oil supply port 9A by being in pressure contact with the inner peripheral portion of the oil supply port 9A when inserted into the oil supply port 9A. It is fitted.

  In the insertion portion 27B, an upper limit mark 27a indicating the upper limit of the lubricating oil amount inside the mission case 9 and a lower limit mark 27b indicating the lower limit are recessed and formed at a predetermined interval in the vertical direction.

  That is, the joint member 27 is configured to be used as an oil gauge for checking the amount and state of the lubricating oil stored in the mission case 9. The oil supply port 9A of the mission case 9 is also used as an oil inspection port and a connection port to which the return oil path 25 from the continuously variable transmission 8 is connected.

  As shown in FIGS. 1 to 3, the steering operation system 15 includes a hydraulic power steering device 29 that assists the steering operation, a steering operation shaft 30, a gear-type reduction mechanism 31, a pitman arm 32, and the steering wheel 16. The left and right front wheels 10 are linked to each other through a pair of left and right tie rods 33.

  Although illustration is omitted, the power steering device 29 is supplied with lubricating oil stored in the transmission case 9 as hydraulic oil.

  As shown in FIGS. 2 to 4, the return oil from the power steering device 29 is returned to the mission case 9 via the dedicated return oil passage 34 and the return oil passage 25 of the continuously variable transmission 8. The return oil passage 34 is formed by an oil passage 35 </ b> A formed in the support base 35 of the power steering device 29 also used as a steering post, and a pipe member 36 extending from the oil passage 35 </ b> A toward the transmission case 9. .

  A rubber hose that can be elastically deformed is employed for the pipe member 36, and its extended end portion is connected to an auxiliary connection portion 27 </ b> C formed in the joint member 27.

  With this configuration, it is not necessary to form a dedicated connection port for connecting the return oil passage 34 from the power steering device 29 to the mission case 9, so that the shape of the mission case 9 can be simplified.

  Further, the mission case 9 can be used as it is in a riding rice transplanter with a specification equipped with an electric power steering device or a riding rice transplanter with a specification not equipped with a power steering device.

  Further, when the seedling planting device 4 is configured to be capable of rolling driving, the joint member 27 is connected to the return oil passage 34 from the power steering device 29 and the hydraulic rolling for driving the seedling planting device 4 to roll. The same mission case 9 can be used by replacing it with one that has two auxiliary connection ports 27C that allow connection of the return oil passage from the apparatus.

  In other words, specifications equipped with a hydraulic power steering device 29, specifications equipped with an electric power steering device, specifications not equipped with a power steering device, specifications equipped with a hydraulic rolling device, equipped with an electric rolling device The common mission case 9 can be used regardless of the specifications to be performed and the specifications not equipped with a rolling device, and as a result, the cost can be effectively reduced.

  In this configuration, the power steering device 29 and the rolling device are the other hydraulic actuators C and the selection target device D.

  Incidentally, although not shown in the figure, the rolling device is a control device provided with a microcomputer or the like. The target rolling angle of the seedling planting device 4 set by the artificial operation of the setting operation tool and the seedling planting detected by the rolling sensor. Based on the rolling angle of the attaching device 4, the operation of the electromagnetic control valve that controls the flow of the hydraulic oil pumped by the hydraulic pump is controlled so that the rolling angle of the seedling planting device 4 is maintained at the target rolling angle. Then, the seedling planting device 4 is configured to be driven to roll by operating the hydraulic cylinder for rolling driving to extend and contract.

    [Another embodiment]

[1] The work vehicle may be an agricultural work vehicle such as a tractor or a combiner, a construction work vehicle such as a backhoe or a wheel dozer, or a lawn mower.

[2] In the configuration of the above embodiment, the return oil path from the elevating device may be connected to the return oil path 25 extending from the continuously variable transmission 8 to the hydraulic oil tank B. In this configuration, the lifting device is also the other hydraulic actuator C.

[3] Any of the return oil path from the continuously variable transmission 8, the return oil path from the power steering device 29, and the return oil path from the rolling device to the return oil path from the lifting device to the hydraulic oil tank B Or you may comprise so that all may be connected. In this configuration, the lifting device is the hydraulic actuator A, and any or all of the continuously variable transmission 8, the power steering device 29, and the rolling device are the other hydraulic actuators C. Further, the continuously variable transmission 8, the power steering device 29, and the rolling device can be set as the selection target device D.

[4] A return oil path from the power steering device 29 is directly connected to the hydraulic oil tank B, and a return oil path from the elevating device, a return oil path from the continuously variable transmission 8, and a rolling device are connected to the return oil path. Any or all of the return oil passages may be connected. In this configuration, the power steering device 29 is the hydraulic actuator A, and any or all of the lifting device, the continuously variable transmission 8, and the rolling device are the other hydraulic actuators C. Further, the lifting device, the continuously variable transmission 8 and the rolling device can be set as the selection target device D.

[5] The seedling planting device 4 is configured to be able to roll, and includes a rolling device that drives the seedling planting device 4 to roll. The return oil path from the rolling device is directly connected to the hydraulic oil tank B, and this return oil path In addition, any or all of the return oil path from the lifting device, the return oil path from the continuously variable transmission 8, and the return oil path from the power steering device 29 may be connected. In this configuration, the rolling device is the hydraulic actuator A, and any or all of the lifting device, the continuously variable transmission 8, and the power steering device 29 are the other hydraulic actuators C. Further, the lifting device, the continuously variable transmission 8, and the power steering device 29 can be used as the selection target device D.

[6] The hydraulic actuator A and other hydraulic actuators C may be a hydraulic clutch, a hydraulic braking device, or the like.

[7] The hydraulic oil tank B may be equipped with a dedicated one, or may be used as a rear axle case or a front axle case.

[8] The return oil passage 34 from the other hydraulic actuator C is connected to a portion closest to the other hydraulic actuator C, such as an intermediate portion in the return oil passage 25 extending from the hydraulic actuator A to the hydraulic oil tank B. You may comprise as follows.

[9] The continuously variable transmission 8 may be a hydrodynamic type or a clutch pack type configured with a plurality of hydraulic clutches.

[10] Various changes can be made to the members used for forming the return oil passages 25 and 34, and the quantity and material thereof. For example, a plurality of return oil passages 25 extending from the hydraulic actuator A to the hydraulic oil tank B are provided. You may make it form from the pipe member 26 and the some joint member 27, and you may make it form the return oil paths 25 and 34 with a resin pipe or a metal pipe.

[11] The joint member 27 may not be used as an oil gauge.

Overall side view of riding rice transplanter Longitudinal side view of the main parts of a riding rice transplanter A longitudinal side view of the main part showing the configuration of the return oil path from the continuously variable transmission to the transmission case A longitudinal rear view of the main part showing the configuration of the return oil path from the power steering device to the mission case

Explanation of symbols

A Hydraulic actuator B Hydraulic oil tank C Other hydraulic actuators D Selection target device 25 Return oil path 26 Pipe member 27 Joint member 34 Return oil path

Claims (3)

  A working oil reduction structure for a work vehicle, wherein a return oil path from another hydraulic actuator is connected to a return oil path from the hydraulic actuator to the hydraulic oil tank.   The working oil reduction structure for a work vehicle according to claim 1, wherein the other hydraulic operation device is a selection target device whose equipment is selected according to specifications. A pipe member extending from the hydraulic actuator toward the hydraulic oil tank through the return oil path from the hydraulic actuator, and a joint member connecting an extended end of the pipe member to the hydraulic oil tank And formed from
The working oil reduction structure for a work vehicle according to claim 1, wherein a return oil passage from the other hydraulic operation device is connected to the joint member.

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