JP2007244318A - Apparatus for lifting and lowering implement of working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for lifting and lowering an implement of a working vehicle, with which a lifting and lowering lever, etc., are arranged in the vicinity of a driver seat without intervening a link mechanism. <P>SOLUTION: In the working vehicle with which the implement 1 is arranged liftably and lowerably by a hydraulic cylinder 6 on a machine body and a lifting and lowering operation means 71 for operation of extension and contraction of the hydraulic cylinder 6 is arranged near the driver seat 19, a lifting and lowering valve unit 47 integrally equipped with a lifting and lowering main change valve 52 for changing an oil sent to the hydraulic cylinder 6 and a hydraulic valve 60 for regulating the amount of the oil drained from the hydraulic cylinder 6 is installed at the lower part of a fender 80 laid at the side of the driver seat 19 and covering the upper part of the rear wheel 3 of the machine body. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for a work implement lifting apparatus for a work vehicle, and more particularly to a technique for a hydraulic mechanism that raises and lowers a work implement.

Conventionally, a hydraulic case and a hydraulic control valve (control valve) are arranged on the transmission case at the rear of the work vehicle, a hydraulic lift cylinder serving as a hydraulic actuator is housed in the hydraulic case, and a lift arm is rotated by the hydraulic cylinder. A work implement such as a rotary tillage device is mounted on a work implement mounting device disposed at the rear of the work vehicle, and the work implement can be moved up and down by turning the lift arm.
Regarding the hydraulic circuit that supplies oil to the lifting cylinder, when the work machine is raised, oil is fed back to the hydraulic cylinder via a check valve to prevent backflow, and when the work machine is lowered, the hydraulic pressure is controlled by a variable throttle. The descent speed of the work implement is adjusted by adjusting the flow rate of the working oil that returns from the cylinder to the oil tank.
JP 2003-235307 A

  The lift cylinder is operated by a driver by a lift lever or the like. For this reason, lift levers and the like must be placed within reach of the driver while sitting on the driver's seat.Hydraulic mechanisms are often located away from the driver's seat and are Without it, the lifting lever could not be placed near the driver's seat.

  Therefore, in view of such a problem, the present invention provides a working machine lifting device for a work vehicle that can arrange a lifting lever or the like in the vicinity of a driver's seat without using a link mechanism or the like.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  That is, according to the first aspect of the present invention, the working machine is provided on the side of the driver's seat in the work vehicle in which the working machine is provided so as to be movable up and down with respect to the machine body by the hydraulic cylinder and the lifting / lowering operation means for extending and retracting the hydraulic cylinder is disposed in the vicinity of the driver's seat. An elevating valve unit in which an elevating main switching valve for switching oil supply to the hydraulic cylinder and a hydraulic valve for adjusting the oil supply amount drained from the hydraulic cylinder are integrally provided at the lower part of the fender that covers the upper rear wheel of the work vehicle. Is arranged.

  According to a second aspect of the present invention, the elevating lever provided in the elevating valve unit and the operation knob for the hydraulic valve are protruded upward from the fender.

  As effects of the present invention, the following effects can be obtained.

  In Claim 1, since the raising / lowering valve unit is arrange | positioned under a fender, it becomes possible to utilize effectively the space between a fender and a rear wheel. In addition, since the elevating valve unit can be operated directly by the elevating lever without using a link mechanism, the configuration is simplified and the cost can be reduced. In addition, the valve units can be easily connected even when the working machine is attached to the front part or the side part and increased. The valve unit can be easily attached and detached from below the fender and can be maintained.

  According to the second aspect of the present invention, the lifting lever and the knob for operating the hydraulic valve are arranged close to each other, and the maintenance of the lifting valve unit is facilitated.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention. In addition, the following embodiment is an example which actualized this invention, Comprising: It is not the thing of the character which limits the technical scope of this invention.

  FIG. 1 is a side view showing the overall configuration of a tractor according to an embodiment of the present invention, FIG. 2 is a perspective view of a hydraulic valve, FIG. 3 is a partial sectional view of the hydraulic valve, and FIG. FIG. 5 is a side view of the vicinity of the seat of the tractor, and FIG. 6 is a schematic view showing an elevation control hydraulic path.

First, a schematic configuration of a tractor as an example of a work vehicle to which the hydraulic valve of the present invention is applied will be described with reference to FIG.
In FIG. 1, reference numeral 1 denotes a tractor, which includes front wheels 2 and 2 and rear wheels 3 and 3 at the front and rear portions of the airframe, respectively, and a hydraulic cylinder case 5 is fixedly provided at the rear upper part of the transmission case 4.
A single-acting hydraulic cylinder 6 is provided in the hydraulic cylinder case 5, and lift arms 7 and 7 that are rotated by expansion and contraction of the hydraulic cylinder 6 are arranged on both the left and right sides of the hydraulic cylinder case 5. . A bonnet 13 is provided at the front of the machine body, and an engine 16 is housed inside the bonnet. A steering handle 17 is disposed at the rear of the bonnet, and a driver's seat 19 is disposed behind the steering handle 17.

Next, the work implement lifting device 8 will be described. The work implement lifting / lowering device 8 includes a top link 10, a lower link 11, 11, and the like. A rotary tiller 14, which is an example of a work implement, is disposed at the rear end of the work implement lifting / lowering device 8.・ It is connected at 7 so that it can move up and down.
Therefore, the rotary tiller 14 connected to the lift arms 7 and 7 is controlled to be lifted or lowered by expanding and contracting the single-acting hydraulic cylinder 6. However, in this embodiment, the work machine is mounted on the rear part of the machine, but it can also be mounted on the front part of the machine or placed between the front wheel and the rear wheel. It is also possible to perform a raising / lowering operation by providing a valve unit.
A lift rod 15 and a tilt cylinder 18 are interposed between the lift arms 7 and 7 and the lower links 11 and 11.

  Further, the tilting cylinder 18 is a double-acting type, and is expanded and contracted by switching a control valve, which will be described later, so that the rotary tiller 14 can be tilted in the rolling direction (left-right direction), and the horizontal (posture) control of the rotary tiller 14 is performed. Can be performed.

Next, the rotary tiller 14 will be described. The rotary tilling device 14 pivotally supports a rear cover 36 at a rear portion of the tilling portion 34 that covers the upper portion of the tilling portion 34, a tilling portion 34 that covers the upper portion of the tilling portion 34, and turns the rear cover 36. One end of a push-pull wire 37 that detects the angle of the rear cover 36 and transmits the rotation amount of the rear cover 36 to a hydraulic operation link described later is attached to the moving base.
In this embodiment, a rotary tiller is used as an example of a working machine. However, it is also possible to connect a mower (mower) or a fertilizer spreader.

Next, the hydraulic circuit will be described with reference to FIGS.
Pressure oil from a hydraulic pump 46 driven by the engine 16 is sent to a lift control hydraulic circuit (lift valve unit) 47. As shown in FIG. 7, the lift control hydraulic circuit 47 includes a relief valve 51, a lift main switching valve 52, a check valve 53, a variable throttle 54, a hydraulic cylinder 6, and the like. The lift arm 7 is rotated. The main switching valve 52 is composed of a three-port three-position switching valve. In the neutral position, the secondary-side cylinder port 52a is blocked, and the primary-side pump port 52c and the drain port 52b are communicated with each other. The working machine is held at a desired height so that the hydraulic oil does not drain. When the elevating lever 71 as the elevating operation means is operated to the ascending side and the spool is slid to switch to the A position, the pump port 52c and the cylinder port 52a are communicated, and the pressure oil from the hydraulic pump 46 is supplied to the check valve. The oil is fed to the hydraulic cylinder 6 through 53 and the hydraulic cylinder 6 is extended to raise the rotary tiller 14.
Further, when the elevating lever 71 is operated to the lower side and the spool is slid to switch to the B position, the cylinder port 52a and the drain port 52b are communicated, and the hydraulic oil in the hydraulic cylinder 6 is flowed by the variable throttle 54. Is restricted, the oil tank (mission case 4) is returned to, and the rotary tiller 14 descends slowly.

In the present invention, the variable throttle 54 and the check valve 53 are integrally formed to constitute the hydraulic valve 60. Hereinafter, the hydraulic valve 60 will be described.
The hydraulic valve 60 adjusts the amount of oil that is drained from the hydraulic cylinder 6. A flow path is formed in the cylindrical case body 63, and the valve body 65 is slidably disposed in the flow path to be variable. A restrictor 54 is formed, the valve body 65 is formed in a cylindrical shape to form a flow path in the valve body 65, and a steel ball 67 and an elastic body 66 are accommodated in the valve body 65 so that the check valve 53 is provided. The adjustment shaft 64 is fixed to one end of the valve body 65, the knob 64a is provided at the other end of the adjustment shaft 64, and the valve body 65 is configured to be slidable from the outside of the case body 63.
That is, as shown in FIGS. 2, 3, and 7, the hydraulic valve 60 includes a case body 63 composed of a guide 61 and a holder 62, an adjustment shaft 64, a valve body 65, an elastic body 66, a steel ball 67, and the like. Consists of The holder 62 is substantially hollow and has an outer shape of a polygonal column, and a central hole is provided with a cylindrical hole. The upper part of the holder 62 is substantially hollow and the outer shape is formed in a polygonal columnar shape, and the guide 61 provided with a cylindrical hole is screwed into the center part. A thread groove (female thread) is provided. An oil hole 62 a perpendicular to the axial direction of the holder 62 is formed through the lower portion of the holder 62, and the oil hole 62 a communicates with the suction port 47 c of the hydraulic cylinder 6. The lower end of the holder is configured as an oil hole 62b, and the oil hole 62b communicates with the cylinder port 52a of the main switching valve 52.

  On the other hand, the adjustment shaft 64 has a knob 64 a fixed at one end (upper end in FIG. 3), a thread (male thread) formed in the middle in the longitudinal direction, and is screwed into the guide 61. A through hole 64b is formed in the upper part of the adjustment shaft 64 at a right angle to the axial direction so that it can be rotated by inserting a screwdriver or the like when it becomes hard and cannot be gripped and rotated. ing. The valve body 65 is constituted by a hollow cylindrical member, and the lower end of the shaft 64 is inserted into the upper part of the valve body 65, and a pin 65a is passed through and fixed to both. An elastic body 66 composed of a spring or the like and a steel ball 67 are accommodated inside the cylinder of the valve body 65, and the inside of the lower end of the cylindrical portion of the valve body 65 is formed as a valve seat, and the steel ball 67 is attached to the valve seat. It is possible to close by contacting. The steel ball 67 is biased downward by the elastic body 66 to form a check valve 53 so as to close the lower end of the cylindrical portion. An oil hole 65 b perpendicular to the axial center (longitudinal) direction of the valve body 65 is provided through the side surface of the upper position of the steel ball 67 below the valve body 65, and is provided in the holder 62. The oil hole 62 a is arranged so as to communicate with the oil hole 62 a and is arranged so as to communicate with the suction port 47 c of the hydraulic cylinder 6.

  Further, a valve seat 62c is formed on the inner surface of the holder 62 below the oil hole 62a, and the lower end of the valve body 65 is in contact with the oil hole 62b so that the oil hole 62b is closed. The adjustment shaft 64 and the valve body 65 are connected and fixed by a pin 65a. When the knob 64a is gripped and rotated, the adjustment shaft 64 slides in the vertical direction with respect to the guide 61 (case body 63). The valve body 65 is also slid up and down integrally. That is, by sliding the adjustment shaft 64 in the vertical direction, it is possible to adjust the gap between the outer periphery of the lower end of the valve body 65 and the valve seat 62 c formed on the inner wall of the holder 62, and the suction port 47 c of the hydraulic cylinder 6. And a variable throttle 54 for adjusting the flow rate between the main switching valve 52 and the cylinder port 52a of the main switching valve 52.

In such a configuration, when the main switching valve 52 is switched to the A position in order to raise the rotary tiller 14, the pressure oil flows from the cylinder port 52a into the oil hole 62b and is urged downward. 67 is pushed up, and oil is supplied from the suction port 47 c to the hydraulic cylinder 6 through the oil hole 65 a provided in the holder 62 from the oil hole 65 b provided in the valve body 65.
On the other hand, when the main switching valve 52 is switched to the B position in order to lower the rotary tiller 14, the hydraulic oil in the hydraulic cylinder 6 flows into the oil hole 62a from the suction port 47c. However, since the steel ball 67 is urged downward by the elastic body 66 inside the valve body 65, it cannot flow in, and the gap between the lower outer wall of the valve body 65 and the inner wall below the holder 62 leads to the oil hole 62 b. Will be sent. Since the gap between the lower outer wall of the valve body 65 and the inner wall below the holder 62 can be changed by sliding the adjustment shaft 64 up and down, the flow rate of the hydraulic oil can be adjusted, and the rotary tiller 14 can be adjusted. The descent speed can be changed. Then, when the work implement is raised, the knob 64a is turned and tightened to close the gap between the lower outer wall of the valve body 65 and the inner wall below the holder 62, so that it can be held in the raised position, and a stop valve is obtained. Can do.

With the configuration as described above, the hydraulic valve 60 includes the variable throttle 54 and the check valve 53 that are integrally housed in one case body 63 and disposed in the vicinity thereof, so that the valve body 65 of the variable throttle 54 is provided. Can be used as a housing for the steel ball 67 of the check valve 53, and the structure is simple and the number of parts can be reduced.
With this configuration, it is possible to save space as compared with the case where the check valve and the variable throttle are provided separately. In addition, the unitization facilitates design and arrangement.

Next, the arrangement of the lift valve unit 47 will be described.
As shown in FIG. 4, the lift valve unit 47 houses the hydraulic valve 60, the main switching valve 52, and the relief valve 51 in a valve case 72, and a lift lever for raising and lowering the work implement from the valve case 72. 71 and a knob 64a for adjusting the lowering speed of the work implement or for performing locking operation at the raised position.
That is, as shown in FIGS. 4 and 5, when the arrow direction F is forward, the main switching valve 52 is arranged on one side (front side) of the valve case 72, and the elevating lever 71 protrudes forward and upward. The hydraulic valve 60 is disposed at the rear portion of 72, and the case body 63 and the knob 64a protrude upward. The suction port 47c protrudes laterally from the side of the case body 63.
Further, a pump port 47a for connecting to the hydraulic pump protrudes from one side surface of the valve case 72, and a drain port 47b for connecting to the transmission case 4 protrudes from the other side surface. The relief valve 51 is configured to be detachable from the front surface of the valve case 72.

  With this configuration, the elevating valve unit 47 is disposed below the fender 80, so that the space between the fender 80 and the rear wheel 3 can be used effectively. Further, since the elevating valve unit 47 can be directly operated by the elevating lever 71 without using a link mechanism, the configuration is simplified and the cost can be reduced. In addition, the valve units can be easily connected even when the working machine is attached to the front part or the side part and increased. The elevating valve unit 47 can be easily attached and detached from below the fender 80 and can be maintained.

  As shown in FIG. 5, the elevating valve unit 47 is provided at the inner lower portion of the fender 80 on the side of the driver's seat 19. That is, a predetermined space is formed between the upper end portion of the rear wheel 3 and the fender 80 covering the upper portion thereof, and the lift valve unit 47 is disposed in this space. The knob 64a and the lift lever 71 are disposed so as to protrude upward from a lever guide formed on the upper surface of the fender 80 between the driver's seat 19 and the assist bar 80a provided on the fender 80. In this way, it is possible to adjust the lifting / lowering speed of the rotary tiller 14 and the lowering speed of the rotary tiller 14 while sitting on the driver's seat 19.

With this configuration, it is not necessary to connect the lifting lever disposed on the side of the driver's seat 19 and the control valve disposed on the side of the hydraulic case as in the prior art, and the lifting and lowering disposed on the lifting valve unit 47 is not necessary. The lever 71 can be directly operated. In addition, maintenance of the lift valve unit is facilitated.
In this embodiment, one valve case is used, but it is possible to connect two or more. By using two or more connected, it is possible to use other work machines (front loader or the like) while using the rotary tiller.

The side view which showed the whole structure of the tractor which concerns on one Example of this invention. The perspective view of a hydraulic valve. 1 is a partial cross-sectional view of a hydraulic valve. The perspective view of a raising / lowering valve unit. The side view near the seat of a tractor. The schematic diagram which showed the hydraulic path for elevation control.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tractor 6 Hydraulic cylinder 7 Lift arm 14 Rotary tiller 47 Lifting valve unit 60 Hydraulic valve 71 Lifting lever 72 Valve case

Claims (2)

  In a work vehicle in which a work machine is provided so as to be movable up and down with respect to the machine body by a hydraulic cylinder, and an elevating operation means for extending and retracting the hydraulic cylinder is arranged in the vicinity of the driver's seat, The elevating valve unit is integrally provided with an elevating / lowering main switching valve for switching oil supply to the hydraulic cylinder and a hydraulic valve for adjusting the oil supply amount drained from the hydraulic cylinder at the lower part of the covering fender. Working machine lifting device for work vehicle. The working machine lifting / lowering device for a work vehicle according to claim 1, wherein a lifting lever and a hydraulic valve operating knob provided in the lifting / lowering valve unit are protruded upward from the fender.

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