JP2023184016A - Service vehicle - Google Patents

Abstract

To inhibit attitude change of a machine body in a service vehicle in which driving wheels are supported by multiple bending and stretching mechanisms.SOLUTION: A service vehicle includes: bending and stretching mechanisms extending from a machine body; driving wheels 5 each supported by an extending end of the bending and stretching mechanism; hydraulic cylinders 31, 32 which enable bending and stretching operation of the bending and stretching mechanisms; and cylinder control valves 41, 42 which operate supply and discharge of a working fluid to and from the hydraulic cylinders 31, 32. The service vehicle includes cylinder check valves 49, 50, 55, 56 which allow supply of the working fluid from the cylinder control valves 41, 42 to the hydraulic cylinders 31, 32 and prevent discharge of the working fluid from the hydraulic cylinders 31, 32 in a state that the cylinder control valves 41, 42 are operated to neutral positions 41a, 42a.SELECTED DRAWING: Figure 7

Description

TECHNICAL FIELD The present invention relates to a work vehicle suitable for traveling on uneven or sloping work sites.

An example of the above-mentioned work vehicle is disclosed in Patent Document 1.
In Patent Document 1, a bending/stretching mechanism is attached to a plurality of locations on a fuselage body and extends from the fuselage body, and wheels for running are supported at the extending end portions of the bending/stretching mechanism. A hydraulic cylinder for bending and extending the bending mechanism and a cylinder control valve for supplying and discharging hydraulic oil to the hydraulic cylinder are provided.
By bending/stretching the bending/stretching mechanism using a hydraulic cylinder, the machine can travel while maintaining it horizontally without being affected by the unevenness or slope of the work area.

JP 2020-1443 Publication

In the work vehicle of Patent Document 1, for example, if the hydraulic cylinder is kept in a stopped state for a long time, the weight of the machine body is applied to the hydraulic cylinder, causing hydraulic oil to leak from the hydraulic cylinder and change the attitude of the machine body. there's a possibility that.

An object of the present invention is to suppress changes in the posture of a work vehicle in which running wheels are supported by a plurality of bending/extending mechanisms.

The work vehicle of the present invention includes a body, a bending/stretching mechanism attached to a plurality of locations on the body and extending from the body, traveling wheels supported at an extending end of the bending/stretching mechanism, and the bending/stretching mechanism. A hydraulic cylinder capable of bending and extending the mechanism, and a cylinder control valve for supplying and discharging hydraulic oil to and from the hydraulic cylinder are provided, and the cylinder control valve allows the hydraulic oil to be supplied to the hydraulic cylinder, and controls the cylinder. A cylinder check valve is provided that prevents discharge of hydraulic fluid from the hydraulic cylinder when the valve is operated to a neutral position.

According to the present invention, in a work vehicle in which traveling wheels are supported by a plurality of bending/extending mechanisms, a cylinder check valve is provided for a hydraulic cylinder that operates the bending/extending mechanisms.
As a result, even if the hydraulic oil tries to leak from the hydraulic cylinder, the cylinder check valve will prevent the hydraulic oil from leaking, so the hydraulic cylinder will not operate due to the hydraulic oil leak, and the attitude of the aircraft will change. can be suppressed.

In the present invention, a rising oil passage supplies hydraulic oil from the cylinder control valve to the hydraulic cylinder for operating the hydraulic cylinder so that the bending mechanism lifts the aircraft body; a descending oil passage that supplies hydraulic oil from the cylinder control valve to the hydraulic cylinder to operate the hydraulic cylinder so as to be operated downward, and the cylinder check valve is connected to the ascending oil passage and the descending oil passage. When hydraulic oil is supplied from the cylinder control valve to the ascending oil passage, the cylinder check valve of the descending oil passage is opened by pilot hydraulic oil branched from the ascending oil passage; When hydraulic oil is supplied from the cylinder control valve to the descending oil passage, it is preferable that the cylinder check valve of the ascending oil passage is opened by pilot hydraulic oil branched from the descending oil passage.

According to the present invention, since the cylinder check valve is provided in the ascending oil passage and the descending oil passage, even if hydraulic oil attempts to leak from the hydraulic cylinder through the ascending oil passage and the descending oil passage, the hydraulic oil from the hydraulic cylinder will not leak. leakage is prevented by cylinder check valves in the ascending and descending oil passages.
This prevents the hydraulic cylinder from operating in the upward and downward directions of the aircraft due to leakage of hydraulic oil, thereby suppressing changes in the attitude of the aircraft.

In the present invention, the bending and stretching mechanism includes a first link whose one end side is attached to the body so as to be swingable back and forth around a first axis along the left-right direction, and whose other end side is a first link extending downward from the body. and a first link whose one end side is attached to the lower part of the first link so as to be swingable up and down about a second axis along the left-right direction, and whose other end side extends from the lower part of the first link along the front-rear direction. a first hydraulic cylinder that swings the first link about the first axis; and a second hydraulic cylinder that swings the second link about the second axis. 2 said hydraulic cylinders, a first said cylinder control valve for supplying and discharging hydraulic oil to said first said hydraulic cylinder, and a second said cylinder control valve for supplying and discharging hydraulic oil to said second said hydraulic cylinder; The ascending oil passage is configured to supply hydraulic oil for operating the second hydraulic cylinder such that the other end of the second link is operated downward relative to the first link. It is an oil passage that supplies oil from the cylinder control valve to the second hydraulic cylinder, and the descending oil passage is configured to supply the second hydraulic pressure so that the other end side of the second link is raised relative to the first link. An oil passage that supplies hydraulic oil for operating a cylinder from the second cylinder control valve to the second hydraulic cylinder, and is configured such that the other end of the first link is operated away from the aircraft body. A separation oil passage that supplies hydraulic oil for operating the first hydraulic cylinder from the first cylinder control valve to the first hydraulic cylinder, and the other end side of the first link is operated to the side where the other end side approaches the aircraft body. an approach oil passage that supplies hydraulic oil for operating the first hydraulic cylinder from the first cylinder control valve to the first hydraulic cylinder, and the cylinder check valve is configured to operate the first hydraulic cylinder. When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, pilot hydraulic oil branched from the separating oil passage controls the cylinder check valve in the approaching oil passage. It is preferable that the opening operation is performed.

According to the present invention, when hydraulic oil is supplied and discharged from the second cylinder control valve to the second hydraulic cylinder, and the second hydraulic cylinder lowers the other end of the second link with respect to the first link. , the fuselage is operated to rise, and when the other end of the second link is operated to rise relative to the first link by the second hydraulic cylinder, the fuselage is operated to descend.

As a result, the second cylinder control valve supplies hydraulic oil to the second hydraulic cylinder so that the other end of the second link is operated downward relative to the first link. The road becomes a rising oil road.
An oil passage that supplies hydraulic oil from the second cylinder control valve to the second hydraulic cylinder to operate the second hydraulic cylinder so that the other end of the second link is operated upward relative to the first link. This becomes a descending oil passage.

According to the present invention, the second link extends from the lower part of the first link along the front-rear direction.
As a result, when the other end of the first link is swung away from the fuselage by the first hydraulic cylinder, the other end of the second link and the wheels are moved away from the fuselage and at the same time are lifted relative to the fuselage. and the aircraft is operated to descend.
When the other end of the first link is swung toward the aircraft by the first hydraulic cylinder, the other end of the second link and the wheels are moved downward relative to the aircraft at the same time as they approach the aircraft. , the aircraft is operated to ascend.

According to the present invention, when the other end side of the first link is operated to swing by the first hydraulic cylinder, the hydraulic oil that swings the other end side of the first link away from the aircraft body is supplied to the first hydraulic cylinder. A cylinder check valve is provided in the approaching oil path of the separation oil path that supplies the oil and the approach oil path that supplies the first hydraulic cylinder with hydraulic oil that swings the other end side of the first link toward the aircraft body. It is provided.

When hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, the hydraulic oil is supplied to the first hydraulic cylinder through the cylinder check valve of the approaching oil passage, and the other end of the first link is connected to the aircraft. The first hydraulic cylinder operates on the side approaching the aircraft (ascending side of the aircraft), and the hydraulic oil discharged from the first hydraulic cylinder is discharged from the separation oil passage through the first cylinder control valve. Ru.

When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, the hydraulic oil is supplied to the first hydraulic cylinder, and the other end side of the first link moves away from the aircraft (lowering side of the aircraft). The first hydraulic cylinder is actuated. Since the pilot hydraulic oil branched from the separating oil passage opens the cylinder check valve of the approaching oil passage, the hydraulic oil discharged from the first hydraulic cylinder is transferred from the approaching oil passage and the cylinder check valve of the approaching oil passage to the first oil passage. 1 cylinder control valve.

If hydraulic oil leaks from the first hydraulic cylinder when the first cylinder control valve is operated to the neutral position and the first hydraulic cylinder is stopped, the weight of the aircraft causes the other end of the first link to move away from the aircraft. Since the first hydraulic cylinder tends to operate on the leaving side, the hydraulic oil of the first hydraulic cylinder tends to leak through the approaching oil passage.

According to the present invention, since the cylinder check valve is provided in the approaching oil passage, even if hydraulic oil attempts to leak from the first hydraulic cylinder through the approaching oil passage, hydraulic oil will not leak from the first hydraulic cylinder. However, this is prevented by the cylinder check valve in the approach oil path, and the first hydraulic cylinder will not operate when the other end of the first link moves away from the aircraft (the downward direction of the aircraft) due to hydraulic oil leakage. This suppresses changes in the aircraft's attitude.

In the present invention, the cylinder check valve is provided in the separating oil passage, and when hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, a pilot operation branched from the approaching oil passage is provided. Preferably, the cylinder check valve of the separation oil passage is opened by oil.

According to the present invention, the cylinder check valve is provided not only in the approaching oil passage but also in the separating oil passage.
When hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, the hydraulic oil is supplied to the first hydraulic cylinder through the cylinder check valve of the approaching oil passage, and the other end of the first link is connected to the aircraft. The first hydraulic cylinder is activated on the side approaching (the rising side of the aircraft). Since the cylinder check valve of the separating oil passage is opened by the pilot hydraulic oil branched from the approaching oil passage, the hydraulic oil discharged from the first hydraulic cylinder is transferred from the separating oil passage and the cylinder check valve of the separating oil passage to the cylinder check valve of the separating oil passage. 1 cylinder control valve.

When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, the hydraulic oil is supplied to the first hydraulic cylinder through the cylinder check valve of the separating oil passage, and the other end of the first link is connected to the aircraft. The first hydraulic cylinder operates on the side away from the aircraft (the descending side of the aircraft). Since the pilot hydraulic oil branched from the separating oil passage opens the cylinder check valve of the approaching oil passage, the hydraulic oil discharged from the first hydraulic cylinder is transferred from the approaching oil passage and the cylinder check valve of the approaching oil passage to the first oil passage. 1 cylinder control valve.

According to the present invention, since the cylinder check valve is provided in the approaching oil passage and the separating oil passage, even if the hydraulic oil attempts to leak from the first hydraulic cylinder through the approaching oil passage and the separating oil passage, the cylinder check valve is provided in the approaching oil passage and the separating oil passage. Leakage of hydraulic fluid from the hydraulic cylinder is prevented by cylinder check valves in the approaching oil passage and the separating oil passage.
As a result, the first hydraulic cylinder will not operate when the other end of the first link approaches the aircraft or moves away from the aircraft (ascent side and descending side of the aircraft) due to hydraulic oil leak, and the attitude of the aircraft Changes can be suppressed.

In the present invention, a rising oil passage supplies hydraulic oil from the cylinder control valve to the hydraulic cylinder for operating the hydraulic cylinder so that the bending mechanism lifts the aircraft body; A descending oil passage is provided for supplying hydraulic oil from the cylinder control valve to the hydraulic cylinder for operating the hydraulic cylinder so as to be operated downward, and the cylinder check valve is provided in the ascending oil passage. Preferably, when hydraulic oil is supplied from the cylinder control valve to the descending oil passage, the cylinder check valve of the ascending oil passage is opened by pilot hydraulic oil branched from the descending oil passage.

According to the present invention, when the bending and stretching mechanism is actuated by the hydraulic cylinder and the aircraft is raised or lowered, an ascending oil passage supplies hydraulic oil to the hydraulic cylinder to actuate the lifting side of the airframe, and an operation to actuate the lowering side of the airframe. A cylinder check valve is provided in the ascending oil passage among the descending oil passages that supply oil to the hydraulic cylinders.

When hydraulic oil is supplied from the cylinder control valve to the ascending oil passage, the hydraulic oil passes through the cylinder check valve in the ascending oil passage and is supplied to the hydraulic cylinder, and the hydraulic cylinder operates on the ascending side of the aircraft. Hydraulic oil discharged from the cylinder is discharged from the descending oil passage through the cylinder control valve.

When hydraulic oil is supplied from the cylinder control valve to the descending oil passage, the hydraulic oil is supplied to the hydraulic cylinder, and the hydraulic cylinder operates on the downward side of the aircraft body. Since the cylinder check valve in the ascending oil passage is opened by the pilot hydraulic oil branched from the descending oil passage, the hydraulic oil discharged from the hydraulic cylinder is transferred from the ascending oil passage and the cylinder check valve in the ascending oil passage to the cylinder control valve. It passes through and is discharged.

If hydraulic oil leaks from the hydraulic cylinder when the cylinder control valve is operated to the neutral position and the hydraulic cylinder is stopped, the hydraulic cylinder will try to operate in the downward direction due to the weight of the aircraft, so the hydraulic cylinder will not operate. Oil attempts to leak through the rising oil passage.

According to the present invention, since the cylinder check valve is provided in the ascending oil passage, even if the hydraulic oil from the hydraulic cylinder attempts to leak through the ascending oil passage, the leakage of the hydraulic oil from the hydraulic cylinder will not occur in the ascending oil passage. This is prevented by the cylinder check valve, and the hydraulic cylinder will not operate toward the lowering side of the aircraft due to leakage of hydraulic oil, suppressing changes in the attitude of the aircraft.

In the present invention, the bending and stretching mechanism includes a first link whose one end side is attached to the body so as to be swingable back and forth around a first axis along the left-right direction, and whose other end side is a first link extending downward from the body. and a first link whose one end side is attached to the lower part of the first link so as to be swingable up and down about a second axis along the left-right direction, and whose other end side extends from the lower part of the first link along the front-rear direction. a first hydraulic cylinder that swings the first link about the first axis; and a second hydraulic cylinder that swings the second link about the second axis. 2 said hydraulic cylinders, a first said cylinder control valve for supplying and discharging hydraulic oil to said first said hydraulic cylinder, and a second said cylinder control valve for supplying and discharging hydraulic oil to said second said hydraulic cylinder; The ascending oil passage is configured to supply hydraulic oil for operating the second hydraulic cylinder such that the other end of the second link is operated downward relative to the first link. It is an oil passage that supplies oil from the cylinder control valve to the second hydraulic cylinder, and the descending oil passage is configured to supply the second hydraulic pressure so that the other end side of the second link is raised relative to the first link. An oil passage that supplies hydraulic oil for operating a cylinder from the second cylinder control valve to the second hydraulic cylinder, and is configured such that the other end of the first link is operated away from the aircraft body. A separation oil passage that supplies hydraulic oil for operating the first hydraulic cylinder from the first cylinder control valve to the first hydraulic cylinder, and the other end side of the first link is operated to the side where the other end side approaches the aircraft body. an approach oil passage that supplies hydraulic oil for operating the first hydraulic cylinder from the first cylinder control valve to the first hydraulic cylinder, and the cylinder check valve is configured to operate the first hydraulic cylinder. When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, pilot hydraulic oil branched from the separating oil passage controls the cylinder check valve in the approaching oil passage. It is preferable that the opening operation is performed.

According to the present invention, when hydraulic oil is supplied and discharged from the second cylinder control valve to the second hydraulic cylinder, and the second hydraulic cylinder lowers the other end of the second link with respect to the first link. , the fuselage is operated to rise, and when the other end of the second link is operated to rise relative to the first link by the second hydraulic cylinder, the fuselage is operated to descend.

As a result, the second cylinder control valve supplies hydraulic oil to the second hydraulic cylinder so that the other end of the second link is operated downward relative to the first link. The road becomes a rising oil road.
An oil passage that supplies hydraulic oil from the second cylinder control valve to the second hydraulic cylinder to operate the second hydraulic cylinder so that the other end of the second link is operated upward relative to the first link. This becomes a descending oil passage.

According to the present invention, the second link extends from the lower part of the first link along the front-rear direction.
As a result, when the other end of the first link is swung away from the fuselage by the first hydraulic cylinder, the other end of the second link and the wheels are moved away from the fuselage and at the same time are lifted relative to the fuselage. and the aircraft is operated to descend.
When the other end of the first link is swung toward the aircraft by the first hydraulic cylinder, the other end of the second link and the wheels are moved downward relative to the aircraft at the same time as they approach the aircraft. , the aircraft is operated to ascend.

According to the present invention, when the other end side of the first link is operated to swing by the first hydraulic cylinder, the hydraulic oil that swings the other end side of the first link away from the aircraft body is supplied to the first hydraulic cylinder. A cylinder check valve is provided in the approaching oil path of the separation oil path that supplies the oil and the approach oil path that supplies the first hydraulic cylinder with hydraulic oil that swings the other end side of the first link toward the aircraft body. It is provided.

When hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, the hydraulic oil is supplied to the first hydraulic cylinder through the cylinder check valve of the approaching oil passage, and the other end of the first link is connected to the aircraft. The first hydraulic cylinder operates on the side approaching the aircraft (ascending side of the aircraft), and the hydraulic oil discharged from the first hydraulic cylinder is discharged from the separation oil passage through the first cylinder control valve. Ru.

When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, the hydraulic oil is supplied to the first hydraulic cylinder, and the other end side of the first link moves away from the aircraft (lowering side of the aircraft). The first hydraulic cylinder is actuated. Since the pilot hydraulic oil branched from the separating oil passage opens the cylinder check valve of the approaching oil passage, the hydraulic oil discharged from the first hydraulic cylinder is transferred from the approaching oil passage and the cylinder check valve of the approaching oil passage to the first oil passage. 1 cylinder control valve.

If hydraulic oil leaks from the first hydraulic cylinder when the first cylinder control valve is operated to the neutral position and the first hydraulic cylinder is stopped, the weight of the aircraft causes the other end of the first link to move away from the aircraft. Since the first hydraulic cylinder tends to operate on the leaving side, the hydraulic oil of the first hydraulic cylinder tends to leak through the approaching oil passage.

According to the present invention, since the cylinder check valve is provided in the approaching oil passage, even if hydraulic oil attempts to leak from the first hydraulic cylinder through the approaching oil passage, hydraulic oil will not leak from the first hydraulic cylinder. However, this is blocked by the cylinder check valve in the approaching oil passage, and the first hydraulic cylinder will not operate when the other end of the first link moves away from the aircraft (the descending side of the aircraft) due to hydraulic oil leakage. , the attitude change of the aircraft is suppressed.

In the present invention, the cylinder check valve is provided in the separating oil passage, and when hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, a pilot operation branched from the approaching oil passage is provided. Preferably, the cylinder check valve of the separation oil passage is opened by oil.

According to the present invention, the cylinder check valve is provided not only in the approaching oil passage but also in the separating oil passage.
When hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, the hydraulic oil is supplied to the first hydraulic cylinder through the cylinder check valve of the approaching oil passage, and the other end of the first link is connected to the aircraft. The first hydraulic cylinder operates on the side approaching (the rising side of the aircraft). Since the cylinder check valve of the separating oil passage is opened by the pilot hydraulic oil branched from the approaching oil passage, the hydraulic oil discharged from the first hydraulic cylinder is transferred from the separating oil passage and the cylinder check valve of the separating oil passage to the cylinder check valve of the separating oil passage. 1 cylinder control valve.

When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, the hydraulic oil is supplied to the first hydraulic cylinder through the cylinder check valve of the separating oil passage, and the first link is moved away from the aircraft. The first hydraulic cylinder operates on the (descending side of the aircraft). Since the pilot hydraulic oil branched from the separating oil passage opens the cylinder check valve of the approaching oil passage, the hydraulic oil discharged from the first hydraulic cylinder is transferred from the approaching oil passage and the cylinder check valve of the approaching oil passage to the first oil passage. 1 cylinder control valve.

According to the present invention, since the cylinder check valve is provided in the approaching oil passage and the separating oil passage, even if the hydraulic oil attempts to leak from the first hydraulic cylinder through the approaching oil passage and the separating oil passage, the cylinder check valve is provided in the approaching oil passage and the separating oil passage. Leakage of hydraulic fluid from the hydraulic cylinder is prevented by cylinder check valves in the approaching oil passage and the separating oil passage.
As a result, the first hydraulic cylinder will not operate when the other end of the first link approaches the aircraft or moves away from the aircraft (ascent side and descending side of the aircraft) due to hydraulic oil leak, and the attitude of the aircraft Changes can be suppressed.

In the present invention, a hydraulic motor capable of rotationally driving the wheels and a motor control valve for supplying and discharging hydraulic oil to and from the hydraulic motor are provided, and the motor control valve allows hydraulic oil to be supplied to the hydraulic motor. However, it is preferable that a motor check valve is provided that prevents discharge of hydraulic fluid from the hydraulic motor when the motor control valve is operated to a neutral position.

According to the present invention, in a work vehicle in which traveling wheels are supported by a plurality of bending/extending mechanisms, when a hydraulic motor and a motor control valve for rotationally driving the wheels are provided, a motor check valve is provided for the hydraulic motor. There is.

Assume that the motor control valve is operated to the neutral position and the hydraulic motor is stopped.
According to the present invention, even if hydraulic oil attempts to leak from the hydraulic motor in the above-mentioned state, the leakage of hydraulic oil from the hydraulic motor is blocked by the motor check valve, so that the hydraulic motor will not operate due to the hydraulic oil leak. This prevents the aircraft from moving.

In the present invention, a normal rotation oil passage supplies hydraulic oil for operating the hydraulic motor in the normal rotation from the motor control valve to the hydraulic motor, and a hydraulic oil passage for supplying hydraulic oil for operating the hydraulic motor in the reverse rotation from the motor control valve to the hydraulic motor. and a reverse rotation oil path for supplying a hydraulic motor, the motor check valve is provided in the forward rotation oil path and the reverse rotation oil path, and hydraulic oil is supplied from the motor control valve to the forward rotation oil path. Then, the motor check valve of the reverse rotation oil passage is opened by the pilot hydraulic oil branched from the normal rotation oil passage, and when hydraulic oil is supplied from the motor control valve to the reverse rotation oil passage, the It is preferable that the motor check valve of the normal rotation oil passage is opened by pilot hydraulic oil branched from the reverse rotation oil passage.

According to the present invention, when the hydraulic motor rotates the wheels in the forward and reverse directions, the forward rotation oil passage supplies the hydraulic oil that rotates the wheels in the forward direction to the hydraulic motor, and the hydraulic oil that causes the wheels to rotate in the reverse direction flows to the hydraulic motor. A motor check valve is provided on both of the supplying reverse oil passages.

When hydraulic oil is supplied from the motor control valve to the normal rotation oil passage, the hydraulic oil is supplied to the hydraulic motor through the motor check valve of the normal rotation oil passage, and the hydraulic motor operates in the normal rotation. Since the motor check valve in the reverse oil path is opened by the pilot hydraulic oil branched from the forward oil path, the hydraulic oil discharged from the hydraulic motor is transferred from the motor check valve in the reverse oil path and the motor control valve to the motor control valve in the reverse oil path. is discharged through the

When hydraulic oil is supplied from the motor control valve to the reversing oil passage, the hydraulic oil is supplied to the hydraulic motor through the motor check valve of the reversing oil passage, and the hydraulic motor operates in reverse. Since the motor check valve in the forward rotation oil path is opened by the pilot hydraulic oil branched from the reverse rotation oil path, the hydraulic oil discharged from the hydraulic motor is transferred from the forward rotation oil path and the motor check valve in the forward rotation oil path to the motor. Exhausted through a control valve.

According to the present invention, since the motor check valve is provided in the forward rotation oil path and the reverse rotation oil path, even if hydraulic oil attempts to leak from the hydraulic motor through the forward rotation oil path and the reverse rotation oil path, the motor check valve will not leak from the hydraulic motor. Leakage of hydraulic oil is prevented by motor check valves in the forward and reverse oil passages.
This prevents the hydraulic motor from operating in forward or reverse rotation due to leakage of hydraulic oil, thereby preventing movement of the aircraft body.

FIG. 3 is a left side view of the work vehicle. FIG. 3 is a plan view of the work vehicle. FIG. 3 is a front view of the work vehicle. FIG. 6 is a left side view of the right front bending and stretching mechanism. FIG. 3 is a plan view of the right front bending and stretching mechanism. FIG. 6 is a front view of the right front bending and stretching mechanism. It is a hydraulic circuit diagram of a hydraulic unit. It is a hydraulic circuit diagram showing the vicinity of a supply oil path and a return oil path. FIG. 2 is a hydraulic circuit diagram of a hydraulic unit in a first alternative embodiment of the invention. FIG. 7 is a hydraulic circuit diagram showing the vicinity of a supply oil path and a return oil path in a second alternative embodiment of the invention.

1 to 10 show remote-controlled and autonomous driving vehicles, and in FIGS. 1 to 10, F indicates the front direction, B indicates the rear direction, and U indicates the upward direction. , D indicates the downward direction, R indicates the right direction, and L indicates the left direction.

(Overall configuration of work vehicle)
As shown in FIGS. 1, 2, and 3, four bending and stretching mechanisms 4 are attached to the right front, left front, right rear, and left rear of the fuselage 1, and extend from the fuselage 1. Right rear and left rear running wheels 5 are supported by the extending end portions of the bending/extending mechanism 4 . The body 1 is supported by four bending/extending mechanisms 4 and wheels 5 to constitute a working vehicle.

(Aircraft configuration)
As shown in FIGS. 1, 2, and 3, right and left frames 6 along the front-rear direction and a plurality of frames 7 along the left-right direction are connected to form a rectangular frame in plan view. ing. A channel-shaped frame 8 when viewed from the front is connected to the front and rear parts of the frame 6, and a frame 9 extending in the front-rear direction is connected to the front and rear frames 8.

A flat plate-like loading section 2 on which luggage and the like can be loaded is attached to the upper part of the frames 6 and 7, and right and left side covers 3 are provided laterally outward of the right and left frames 6.
As described above, the body 1 includes the frames 6 to 9, the mounting section 2, and the like.

In the aircraft body 1, an engine 10 (corresponding to a driving part), a hydraulic pump 11, an oil cooler 12, a hydraulic oil tank 13 (corresponding to a storage part), and a battery 14 are supported by frames 8 and 9. A frame 19 is connected to the rear frame 8 and extends rearward and upward, and a fuel tank 20 is supported by the frame 19.

(Configuration of bending and stretching mechanism)
As shown in FIGS. 1, 2, and 3, the right front bending and stretching mechanism 4 and the left front bending and stretching mechanism 4 have a bilaterally symmetrical configuration, and the right rear bending and stretching mechanism 4 and the left rear bending and stretching mechanism 4 have a bilaterally symmetrical structure. It has a structure. The right front bending/extending mechanism 4 and the right rear bending/extending mechanism 4 have a front-rear symmetrical configuration, and the left front bending/extending mechanism 4 and the left rear bending/extending mechanism 4 have a front-rear symmetrical configuration.

As shown in FIGS. 2 and 3, support brackets 15 are connected to four locations in the fuselage 1: the front and rear parts of the right frame 6 and the front and rear parts of the left frame 6. As shown in FIGS. 4, 5, and 6, the support shaft 16 is connected to the lower part of the support bracket 15 and extends laterally outward.
As shown in FIGS. 1 and 3, the bending and stretching mechanism 4 includes a first link 21 and a second link 22. As shown in FIGS. The right front bending/extending mechanism 4 will be explained below based on FIGS. 4, 5, and 6.

As shown in FIGS. 4, 5, and 6, two first links 21 are provided in a flat plate shape, and a boss portion 21a is connected across the upper portions of the two first links 21. A boss portion 21b is connected to the lower portions of the two first links 21. The boss portion 21a of the first link 21 is attached to the support shaft 16 (body 1) so as to be swingable back and forth around an axis P1 (corresponding to the first axis) along the left-right direction.

Thereby, the first link 21 is attached to the support bracket 15 and the support shaft 16 (body 1) so as to be able to swing back and forth around the axis P1 along the left-right direction, and the other end side is attached to the support bracket 15 and the support shaft 16 (body 1). It extends downward from the support shaft 16 (body 1).

The second link 22 includes a flat first portion 22a, two second portions 22b made of round bars bent into crank shapes, a boss portion 22c, and a fulcrum shaft 22d. The front portion of the first portion 22a and the front portion of the second portion 22b are connected, and the boss portion 22c is vertically connected to the front portion of the first portion 22a and the front portion of the second portion 22b.

The rear part of the first part 22a of the second link 22 is connected to one end of the fulcrum shaft 22d, and the rear part of the second part 22b of the second link 22 is connected to the other end of the fulcrum shaft 22d. There is. The fulcrum shaft 22d of the second link 22 is inserted into the boss portion 21b of the first link 21, and the fulcrum shaft 22d of the second link 22 is centered around the axis P2 (corresponding to the second axis) along the left-right direction. It is attached to the boss portion 21b of the first link 21 so as to be vertically swingable. The auxiliary wheel 17 is supported by the lateral outer end of the fulcrum shaft 22d of the second link 22 so as to be freely rotatable about the axis P2.

As a result, in the front right and front left bending and stretching mechanisms 4, the second link 22 is attached to the lower part of the first link 21 so as to be able to swing up and down about the axis P2 along the left-right direction, and the other end is attached to the lower part of the first link 21. It extends from the lower part of the link 21 toward the front, which is the direction away from the fuselage 1, along the front-rear direction.
In the right rear and left rear bending and stretching mechanisms 4, the second link 22 is attached to the lower part of the first link 21 so as to be able to swing up and down around an axis P2 along the left-right direction, and the other end is attached to the lower part of the first link 22. It extends from the lower part of 21 toward the rear, which is the direction away from the fuselage 1, along the front-rear direction.

(Configuration of bending and stretching operation of bending and stretching mechanism)
As shown in FIGS. 4, 5, and 6, a ring-shaped mounting member 23 is non-rotatably connected to the end of the support shaft 16, and is connected between the support bracket 15 and the first link 21 on the support shaft 16. is non-rotatably connected to the parts. A support bracket 24 is connected across the two mounting members 23.

A double-acting hydraulic cylinder 31 (corresponding to a first hydraulic cylinder) is connected across the support bracket 24 and the lower part of the first link 21 . By expanding and contracting the hydraulic cylinder 31, the first link 21 is swung back and forth around the axis P1 with respect to the support bracket 15 (body 1).

A fulcrum shaft 25 is connected to the second link 22 across the first portion 22a and the second portion 22b, and a double-acting hydraulic cylinder 32 (corresponding to the second hydraulic cylinder) is connected to the first link 21. and the fulcrum shaft 25. By expanding and contracting the hydraulic cylinder 32, the second link 22 is vertically swung around the axis P2 with respect to the first link 21.

As a result, the first link 21 is operated to swing around the axis P1 (first axis) by the hydraulic cylinder 31, and the second link 22 is operated to swing around the axis P2 (second axis) by the hydraulic cylinder 32. By being operated, the bending/stretching mechanism 4 is operated to bend/stretch.

By independently operating the bending/stretching mechanisms 4, the attitude of the machine body 1 can be arbitrarily set depending on the unevenness, inclination, etc. of the work area. When the bending/stretching mechanism 4 is bent/stretched, even if the connecting portion between the first link 21 and the second link 22 approaches the work site, the auxiliary wheels 17 are brought into contact with the work site, so that the first link 21 and The connecting portion with the second link 22 is prevented from coming into contact with the work area.

(Wheel support and drive configuration)
As shown in FIGS. 4, 5, and 6, four wheel support members 26 are provided, and the wheel support members 26 are connected to the second link so that the direction can be changed left and right around the axis P3 along the vertical direction. It is attached to the boss portion 22c of 22.

The wheel 5 is rotatably supported on the right lateral side of the right front wheel support member 26, and is rotatably supported on the left lateral side of the left front wheel support member 26. The wheel 5 is rotatably supported on the right lateral side of the right rear wheel support member 26, and rotatably supported on the left lateral side of the left rear wheel support member 26. A guard member 27 formed by bending a round bar is attached to the wheel support member 26 and arranged to cover the upper part of the wheel 5.

A hydraulic motor 34 is attached to the left lateral side of the right front wheel support member 26 and is attached to the right lateral side of the left front wheel support member 26 . A hydraulic motor 34 is attached to the left lateral side of the right rear wheel support member 26, and is attached to the right lateral side of the left rear wheel support member 26.
The wheels 5 are independently driven forward and backward by the hydraulic motor 34, and the working vehicle is moved forward, backward, and stopped.

(Configuration of wheel steering operation)
As shown in FIGS. 4, 5, and 6, the wheel support member 26 is provided with a bracket 26a, and the first portion 22a of the second link 22 is provided with a bracket 22e. A double-acting hydraulic cylinder 33 is connected across the bracket 26a of the wheel support member 26 and the bracket 22e of the second link 22, and when the hydraulic cylinder 33 is expanded and contracted, four sets of wheel support members are connected. 26, the wheels 5 and the hydraulic motor 34 are each independently operated to change their direction from side to side around the axis P3.

In addition to the wheels 5 being independently driven forward and reverse, the wheels 5 are also independently turned left and right, allowing the work vehicle to turn right and left while moving forward and backward; Lateral movement diagonally forward to the right and diagonally forward to the left, lateral movement diagonally backward right and diagonally backward to the left, and clockwise and counterclockwise super-turns are performed.

(Overview of the configuration for supplying and discharging hydraulic oil to the hydraulic cylinder and hydraulic motor, and overview of the configuration of the hydraulic unit)
As shown in FIGS. 1 and 3, a transmission belt 18 is attached across the output pulley 10a of the engine 10 and the input pulley 11a of the hydraulic pump 11, and the hydraulic pump 11 is driven by the power of the engine 10. There is.

As shown in FIG. 2, a hydraulic unit 28 is provided for the hydraulic cylinders 31, 32, 33 and the hydraulic motor 34 of the four bending/extending mechanisms 4. In the fuselage 1, two hydraulic units 28 are supported by the right frame 6, and two hydraulic units 28 are supported by the left frame 6.

As shown in FIG. 7, the hydraulic unit 28 includes a cylinder control valve 41 (corresponding to a first cylinder control valve), a cylinder control valve 42 (corresponding to a second cylinder control valve), a cylinder control valve 43, and a motor control valve. 44 are provided.

As shown in FIGS. 7 and 8, hydraulic oil is stored in a hydraulic oil tank 13, the hydraulic oil in the hydraulic oil tank 13 is sucked by the hydraulic pump 11, and the hydraulic oil is discharged from the hydraulic pump 11. A supply oil passage 29 is connected between the hydraulic pump 11 and each of the four hydraulic units 28 . In the hydraulic unit 28 , an oil passage 45 branched from the supply oil passage 29 is connected to the cylinder control valves 41 , 42 , 43 and the motor control valve 44 .

Hydraulic oil of the hydraulic pump 11 is supplied to the hydraulic unit 28 (cylinder control valves 41, 42, 43 and motor control valve 44) via the supply oil path 29, and is supplied to the hydraulic unit 28 (cylinder control valves 41, 42, 43 and It is supplied to the hydraulic cylinders 31, 32, 33 and the hydraulic motor 34 from the motor control valve 44).

A return oil passage 30 is connected between the hydraulic oil tank 13 and each of the four hydraulic units 28 (cylinder control valves 41, 42, 43 and motor control valve 44), and the oil cooler 12 is connected to the return oil passage 30. It is set at 30. In the hydraulic unit 28 , oil passages 46 from the cylinder control valves 41 , 42 , 43 and the motor control valve 44 are connected to the return oil passage 30 .

The hydraulic oil of the hydraulic cylinders 31, 32, 33 and the hydraulic motor 34 is discharged to the hydraulic unit 28 (cylinder control valves 41, 42, 43 and motor control valve 44), and the motor control valve 44), and returns to the hydraulic oil tank 13 through the return oil path 30 and the oil cooler 12.

As described above, the cylinder control valves 41, 42, 43 supply and discharge hydraulic oil to and from the hydraulic cylinders 31, 32, 33, and supply the hydraulic oil in the supply oil path 29 to the hydraulic cylinders 31, 32, 33. Then, the hydraulic oil in the hydraulic cylinders 31, 32, 33 is discharged to the return oil path 30. The motor control valve 44 supplies and discharges hydraulic oil to the hydraulic motor 34 , supplies the hydraulic oil in the supply oil passage 29 to the hydraulic motor 34 , and discharges the hydraulic oil in the hydraulic motor 34 to the return oil passage 30 .

(Configuration regarding supply oil path check valve and return oil path check valve)
As shown in FIG. 8, a pilot-operated return oil passage check valve 35 is provided in a portion of the return oil passage 30 on the hydraulic unit 28 side with respect to the oil cooler 12. The return oil passage check valve 35 prevents hydraulic oil from returning to the hydraulic oil tank 13 from the hydraulic unit 28 (cylinder control valves 41 , 42 , 43 and motor control valve 44 ).

A supply oil passage check valve 36 is provided in the supply oil passage 29. The supply oil passage check valve 36 allows hydraulic oil to be supplied from the hydraulic pump 11 to the hydraulic unit 28 (cylinder control valves 41, 42, 43 and motor control valve 44). The supply oil passage check valve 36 prevents hydraulic oil from returning from the hydraulic unit 28 (cylinder control valves 41, 42, 43 and motor control valve 44) to the hydraulic pump 11 when the engine 10 stops and the hydraulic pump 11 stops. do.

A pilot oil passage 68 is connected to a portion of the return oil passage 30 on the hydraulic unit 28 side with respect to the supply oil passage check valve 36 and the return oil passage check valve 35 .
When the hydraulic pump 11 is driven by the engine 10, pilot hydraulic oil branched from the supply oil passage 29 is supplied to the return oil passage check valve 35 via the pilot oil passage 68, and the return oil passage check valve 35 is opened. be done.

As a result, the hydraulic oil of the hydraulic cylinders 31, 32, 33 and the hydraulic motor 34 is discharged via the hydraulic unit 28 (cylinder control valves 41, 42, 43 and motor control valve 44), and the return oil path that has been opened is The oil returns to the hydraulic oil tank 13 through the check valve 35, the return oil path 30, and the oil cooler 12.

When the engine 10 stops and the hydraulic pump 11 stops, the pressure of the pilot hydraulic oil in the pilot oil passage 68 decreases, so the return oil passage check valve 35 is closed, and the hydraulic unit 28 (cylinder control valve 41, 42, 43 and motor control valve 44) from returning to the hydraulic oil tank 13.

(Configuration related to unload valve)
As shown in FIG. 8, the unload oil passage 37 includes a portion of the supply oil passage 29 between the hydraulic pump 11 and the supply oil passage check valve 36, and a portion of the return oil passage 30 between the oil cooler 12 and the return oil passage check valve. 35.

The oil passage 39 is located between a portion of the supply oil passage 29 between the hydraulic pump 11 and the unload oil passage 37 and a portion of the return oil passage 30 between the oil cooler 12 and the unload oil passage 37. A relief valve 40 is provided in the oil passage 39.

An unload valve 38 is provided in the unload oil passage 37. The unload valve 38 has a communicating position 38a and a blocking position 38b, is configured to be electromagnetically operated, and is biased to the communicating position 38a by a spring.

At the communication position 38a of the unload valve 38, the unload oil passage 37 is in a communication state, and the supply oil passage 29 is supplied with hydraulic oil via the unload oil passage 37, the unload valve 38 (communication position 38a), and the return oil passage 30. Connected to tank 13. At the cut-off position 38b of the unload valve 38, the unload oil passage 37 is in the cut-off state, and the connection of the supply oil passage 29 to the hydraulic oil tank 13 is cut off.

While the engine 10 is operating, the unload valve 38 is energized and the unload valve 38 is operated to the cutoff position 38b. When the engine 10 stops, the energization to the unload valve 38 disappears, and the unload valve 38 is operated by the spring to the communicating position 38a, and the pilot hydraulic oil in the pilot oil passage 68 is discharged into the hydraulic oil tank 13. be done.

(Configuration related to the first cylinder control valve that supplies and discharges hydraulic oil to the first hydraulic cylinder that swings the first link back and forth)
As shown in FIG. 7, a separating oil passage 47 and an approaching oil passage 48 are connected across the hydraulic cylinder 31 and the cylinder control valve 41. The cylinder control valve 41 has three positions, a neutral position 41a, a separated position 41b, and an approach position 41c, and is configured to be electromagnetically operated.

Pilot-operated cylinder check valves 49 and 50 are provided in the separating oil passage 47 and the approaching oil passage 48. The cylinder check valves 49 and 50 allow hydraulic oil to be supplied from the cylinder control valve 41 to the hydraulic cylinder 31 and prevent hydraulic oil from being discharged from the hydraulic cylinder 31.

A pilot oil passage 51 is connected between the approach oil passage 48 and the cylinder check valve 49 of the separation oil passage 47, and a pilot oil passage 52 is connected between the separation oil passage 47 and the cylinder check valve 50 of the approach oil passage 48. is connected.

(Operating state of the first cylinder control valve that supplies and discharges hydraulic oil to the first hydraulic cylinder that swings the first link back and forth)
As shown in FIG. 7, when the cylinder control valve 41 is operated to the separation position 41b, the hydraulic oil in the supply oil passage 29 is supplied to the separation oil passage 47, passes through the cylinder check valve 49 in the separation oil passage 47, and the hydraulic oil is The oil is supplied to the oil chamber on the bottom side of the cylinder 31, and the hydraulic cylinder 31 is operated to extend. When the hydraulic cylinder 31 is extended, the other end of the first link 21 is swung away from the body 1 .

As shown in FIGS. 1 to 6, the second link 22 extends from the lower part of the first link 21 in a direction away from the fuselage 1 along the front-rear direction. When the other end side is operated to swing away from the aircraft body 1, the other end side of the second link 22 and the wheels 5 are moved upwardly relative to the aircraft body 1 at the same time as they separate from the aircraft body 1, and the aircraft body 1 is lowered. Be manipulated.

As shown in FIG. 7, when hydraulic oil is supplied from the cylinder control valve 41 (separated position 41b) to the separating oil passage 47, pilot hydraulic oil branched from the separating oil passage 47 approaches via the pilot oil passage 52. The oil is supplied to the cylinder check valve 50 of the oil passage 48, and the cylinder check valve 50 of the approach oil passage 48 is opened. As a result, the hydraulic oil in the oil chamber on the rod side of the hydraulic cylinder 31 passes through the approach oil passage 48, the cylinder check valve 50 of the approach oil passage 48 that has been opened, and the cylinder control valve 41 (separated position 41b). It is discharged into the return oil path 30.

When the cylinder control valve 41 is operated to the approach position 41c, the hydraulic oil in the supply oil passage 29 is supplied to the approach oil passage 48, and the oil on the rod side of the hydraulic cylinder 31 passes through the cylinder check valve 50 of the approach oil passage 48. The oil is supplied to the chamber, and the hydraulic cylinder 31 is contracted. By contracting the hydraulic cylinder 31, the other end of the first link 21 is swung toward the side approaching the body 1.

As shown in FIGS. 1 to 6, the second link 22 extends from the lower part of the first link 21 in a direction away from the fuselage 1 along the front-rear direction. When the other end side is swung toward the side approaching the body 1, the other end side of the second link 22 and the wheels 5 are operated downward relative to the body 1 at the same time as they approach the body 1, and the body 1 Operated to rise.

As shown in FIG. 7, when hydraulic oil is supplied from the cylinder control valve 41 (approach position 41c) to the approach oil passage 48, the pilot hydraulic oil branched from the approach oil passage 48 is separated via the pilot oil passage 51. The oil is supplied to the cylinder check valve 49 of the oil passage 47, and the cylinder check valve 49 of the separation oil passage 47 is opened. As a result, the hydraulic oil in the oil chamber on the bottom side of the hydraulic cylinder 31 passes through the separation oil passage 47, the cylinder check valve 49 of the separation oil passage 47 that has been opened, and the cylinder control valve 41 (approach position 41c). It is discharged into the return oil path 30.

When the cylinder control valve 41 is operated to the neutral position 41a, the pressure of the pilot hydraulic oil in the pilot oil passages 51 and 52 decreases, so the cylinder check valves 49 and 50 in the separating oil passage 47 and the approaching oil passage 48 are opened. Therefore, discharge of the hydraulic oil from the hydraulic cylinder 31 is prevented by the cylinder check valves 49 and 50 of the separating oil passage 47 and the approaching oil passage 48.

As described above, the hydraulic oil that operates the hydraulic cylinder 31 (first hydraulic cylinder) so that the other end side of the first link 21 is operated away from the body 1 (the body 1 is lowered by the bending mechanism 4). is supplied from the cylinder control valve 41 (first cylinder control valve) to the hydraulic cylinder 31 (first hydraulic cylinder) via the separation oil passage 47.

Hydraulic oil that operates the hydraulic cylinder 31 (first hydraulic cylinder) so that the other end side of the first link 21 is operated to the side approaching the aircraft body 1 (the aircraft body 1 is raised by the bending mechanism 4) is used for cylinder control. The oil is supplied from the valve 41 (first cylinder control valve) to the hydraulic cylinder 31 (first hydraulic cylinder) via the approach oil passage 48 .

The cylinder check valves 49 and 50 of the separating oil passage 47 and the approaching oil passage 48 allow hydraulic oil to be supplied from the cylinder control valve 41 (first cylinder control valve) to the hydraulic cylinder 31 (first hydraulic cylinder). , prevents discharge (leakage) of hydraulic fluid from the hydraulic cylinder 31 (first hydraulic cylinder) when the cylinder control valve 41 (first cylinder control valve) is operated to the neutral position 41a.

(Configuration related to the second cylinder control valve that supplies and discharges hydraulic oil to the second hydraulic cylinder that swings the second link up and down)
As shown in FIG. 7, an ascending oil passage 53 and a descending oil passage 54 are connected across the hydraulic cylinder 32 and the cylinder control valve 42. The cylinder control valve 42 has three positions, a neutral position 42a, a raised position 42b, and a lowered position 42c, and is configured to be electromagnetically operated.

Pilot-operated cylinder check valves 55 and 56 are provided in the ascending oil passage 53 and the descending oil passage 54. The cylinder check valves 55 and 56 allow hydraulic oil to be supplied from the cylinder control valve 42 to the hydraulic cylinder 32 and prevent hydraulic oil from being discharged from the hydraulic cylinder 32.

A pilot oil passage 57 is connected between the descending oil passage 54 and the cylinder check valve 55 of the ascending oil passage 53, and a pilot oil passage 58 is connected between the ascending oil passage 53 and the cylinder check valve 56 of the descending oil passage 54. is connected.

(Operating state of the second cylinder control valve that supplies and discharges hydraulic oil to the second hydraulic cylinder that swings the second link up and down)
As shown in FIG. 7, when the cylinder control valve 42 is operated to the ascending position 42b, the hydraulic oil in the supply oil passage 29 is supplied to the ascending oil passage 53, passes through the cylinder check valve 55 in the ascending oil passage 53, and the hydraulic oil is The oil is supplied to the oil chamber on the bottom side of the cylinder 32, and the hydraulic cylinder 32 is operated to extend. When the hydraulic cylinder 32 is extended, the other end of the second link 22 is lowered relative to the first link 21, and the fuselage 1 is raised.

When hydraulic oil is supplied from the cylinder control valve 42 (ascent position 42b) to the ascending oil passage 53, the pilot hydraulic oil branched from the ascending oil passage 53 passes through the pilot oil passage 58 to the cylinder check valve of the descending oil passage 54. 56, and the cylinder check valve 56 of the descending oil passage 54 is opened. As a result, the hydraulic oil in the oil chamber on the rod side of the hydraulic cylinder 32 passes through the descending oil passage 54, the cylinder check valve 56 of the descending oil passage 54 that has been opened, and the cylinder control valve 42 (raised position 42b). It is discharged into the return oil path 30.

When the cylinder control valve 42 is operated to the lower position 42c, the hydraulic oil in the supply oil passage 29 is supplied to the lower oil passage 54, and the oil on the rod side of the hydraulic cylinder 32 passes through the cylinder check valve 56 of the lower oil passage 54. The oil is supplied to the chamber, and the hydraulic cylinder 32 is operated to contract. When the hydraulic cylinder 32 contracts, the other end of the second link 22 is moved upward relative to the first link 21, and the body 1 is moved downward.

When hydraulic oil is supplied from the cylinder control valve 42 (downward position 42c) to the descending oil passage 54, the pilot hydraulic oil branched from the descending oil passage 54 passes through the pilot oil passage 57 to the cylinder check valve in the ascending oil passage 53. 55, and the cylinder check valve 55 of the ascending oil passage 53 is operated to open. As a result, the hydraulic oil in the oil chamber on the bottom side of the hydraulic cylinder 32 passes through the ascending oil passage 53, the cylinder check valve 55 of the ascending oil passage 53 that has been opened, and the cylinder control valve 42 (downward position 42c). It is discharged into the return oil path 30.

When the cylinder control valve 42 is operated to the neutral position 42a, the pressure of the pilot hydraulic oil in the pilot oil passages 57 and 58 decreases, so the cylinder check valves 55 and 56 in the ascending oil passage 53 and the descending oil passage 54 are opened. Therefore, discharge of hydraulic oil from the hydraulic cylinder 32 is prevented by the cylinder check valves 55 and 56 of the ascending oil passage 53 and the descending oil passage 54.

As described above, the hydraulic cylinder 32 (second hydraulic cylinder) is operated so that the other end side of the second link 22 is lowered relative to the first link 21 (the aircraft body 1 is raised by the bending mechanism 4). Hydraulic oil is supplied from the cylinder control valve 42 (second cylinder control valve) to the hydraulic cylinder 32 (second hydraulic cylinder) via the rising oil passage 53.

Hydraulic oil that operates the hydraulic cylinder 32 (second hydraulic cylinder) so that the other end side of the second link 22 is operated upward relative to the first link 21 (the aircraft body 1 is operated downward by the bending mechanism 4) is supplied to the cylinder. The oil is supplied from the control valve 42 (second cylinder control valve) to the hydraulic cylinder 32 (second hydraulic cylinder) via the downward oil passage 54.

The cylinder check valves 55 and 56 of the ascending oil passage 53 and the descending oil passage 54 allow hydraulic oil to be supplied from the cylinder control valve 42 (second cylinder control valve) to the hydraulic cylinder 32 (second hydraulic cylinder). , prevents discharge (leakage) of hydraulic fluid from the hydraulic cylinder 32 (second hydraulic cylinder) when the cylinder control valve 42 (second cylinder control valve) is operated to the neutral position 42a.

(Configuration related to the cylinder control valve that supplies and discharges hydraulic oil to the hydraulic cylinder that changes the direction of the wheels left and right)
As shown in FIG. 7, oil passages 59 and 60 are connected across the hydraulic cylinder 33 and the cylinder control valve 43. The cylinder control valve 43 has three positions, a neutral position 43a, a first position 43b, and a second position 43c, and is configured to be electromagnetically operated.

When looking forward from the aircraft body 1, in the hydraulic unit 28 (cylinder control valve 43) corresponding to the front right wheel 5, when the cylinder control valve 43 is operated to the first position 43b, the hydraulic oil in the supply oil path 29 is The hydraulic oil is supplied to the oil chamber on the bottom side of the hydraulic cylinder 33 , and the hydraulic oil in the oil chamber on the rod side of the hydraulic cylinder 33 is discharged to the return oil path 30 . As a result, the hydraulic cylinder 33 is extended and the right front wheel 5 is steered to the right.

When the cylinder control valve 43 is operated to the second position 43c, the hydraulic oil in the supply oil passage 29 is supplied to the oil chamber on the rod side of the hydraulic cylinder 33, and the hydraulic oil in the oil chamber on the bottom side of the hydraulic cylinder 33 returns. It is discharged into the oil path 30. As a result, the hydraulic cylinder 33 is contracted, and the right front wheel 5 is steered to the left.

When looking forward from the aircraft 1, when the cylinder control valve 43 is operated to the first position 43b in the hydraulic unit 28 (cylinder control valve 43) corresponding to the left front wheel 5, the left front wheel 5 is steered to the left. When the cylinder control valve 43 is operated to the second position 43c, the front left wheel 5 is steered to the right.

When looking rearward from the aircraft body 1, when the cylinder control valve 43 is operated to the first position 43b in the hydraulic unit 28 (cylinder control valve 43) corresponding to the right rear wheel 5, the right rear wheel 5 moves to the right When the cylinder control valve 43 is operated to the second position 43c, the rear right wheel 5 is steered to the left.

When looking rearward from the aircraft 1, when the cylinder control valve 43 is operated to the first position 43b in the hydraulic unit 28 (cylinder control valve 43) corresponding to the left rear wheel 5, the left rear wheel 5 moves to the left When the cylinder control valve 43 is operated to the second position 43c, the rear left wheel 5 is steered to the right.

(Configuration related to the motor control valve that supplies and discharges hydraulic oil to the hydraulic motor)
As shown in FIG. 7, a forward oil passage 61 and a reverse oil passage 62 are connected across the hydraulic motor 34 and the motor control valve 44. The motor control valve 44 has three positions: a neutral position 44a, a forward rotation position 44b, and a reverse rotation position 44c, and is configured to be electromagnetically operated.

Pilot-operated motor check valves 63 and 64 are provided in the forward rotation oil passage 61 and the reverse rotation oil passage 62. The motor check valves 63 and 64 allow hydraulic oil to be supplied from the motor control valve 44 to the hydraulic motor 34 and prevent hydraulic oil from being discharged from the hydraulic motor 34.

A pilot oil passage 65 is connected between the reverse rotation oil passage 62 and the motor check valve 63 of the forward rotation oil passage 61, and a pilot oil passage 65 is connected between the forward rotation oil passage 61 and the motor check valve 64 of the reverse rotation oil passage 62. line 66 is connected.

(Operating state of the motor control valve that supplies and discharges hydraulic oil to the hydraulic motor)
As shown in FIG. 7, when the motor control valve 44 is operated to the normal rotation position 44b, the hydraulic oil in the supply oil passage 29 is supplied to the normal rotation oil passage 61, and the motor check valve 63 in the normal rotation oil passage 61 is activated. The oil is supplied to the hydraulic motor 34, and the hydraulic motor 34 rotates in the normal direction, and the wheels 5 are driven to rotate in the normal direction.

When hydraulic oil is supplied from the motor control valve 44 (forward rotation position 44b) to the forward rotation oil passage 61, the pilot hydraulic oil branched from the normal rotation oil passage 61 flows through the pilot oil passage 66 to the reverse rotation oil passage 62. The motor check valve 64 of the reverse oil passage 62 is opened by being supplied to the motor check valve 64 . As a result, the hydraulic oil of the hydraulic motor 34 passes through the reverse oil passage 62, the motor check valve 64 of the reverse oil passage 62 that has been opened, and the motor control valve 44 (normal rotation position 44b), and enters the return oil passage 30. It is discharged.

When the motor control valve 44 is operated to the reverse position 44c, the hydraulic oil in the supply oil passage 29 is supplied to the reverse oil passage 62, passes through the motor check valve 64 in the reverse oil passage 62, and is supplied to the hydraulic motor 34. The hydraulic motor 34 operates in reverse, and the wheels 5 are driven in reverse.

When hydraulic oil is supplied from the motor control valve 44 (reverse rotation position 44c) to the reverse rotation oil passage 62, pilot hydraulic oil branched from the reverse rotation oil passage 62 passes through the pilot oil passage 65 to check the motor in the forward rotation oil passage 61. The motor check valve 63 of the normal oil passage 61 is opened by being supplied to the valve 63. As a result, the hydraulic oil of the hydraulic motor 34 passes through the normal rotation oil passage 61, the motor check valve 63 of the normal rotation oil passage 61 that has been opened, and the motor control valve 44 (reverse rotation position 44c), and then passes through the return oil passage 30. is discharged.

When the motor control valve 44 is operated to the neutral position 44a, the pressure of the pilot hydraulic oil in the pilot oil passages 65 and 66 decreases, so the motor check valves 63 and 64 in the forward rotation oil passage 61 and the reverse rotation oil passage 62 are opened. It is not operated, and discharge of hydraulic oil from the hydraulic motor 34 is prevented by the motor check valves 63 and 64 of the forward rotation oil passage 61 and the reverse rotation oil passage 62.

As described above, the hydraulic oil that causes the hydraulic motor 34 to rotate in the normal direction is supplied from the motor control valve 44 to the hydraulic motor 34 via the normal rotation oil path 61. Hydraulic oil for operating the hydraulic motor 34 in reverse is supplied to the hydraulic motor 34 from the motor control valve 44 via the reverse oil passage 62 .

The motor check valves 63 and 64 of the forward oil passage 61 and the reverse oil passage 62 permit the supply of hydraulic oil from the motor control valve 44 to the hydraulic motor 34, and the motor control valve 44 is operated to the neutral position 44a. This prevents discharge (leakage) of hydraulic oil from the hydraulic motor 34.

(First alternative embodiment of the invention)
The hydraulic unit 28 may be configured as shown in FIG.
As shown in FIG. 9, a pilot-operated cylinder check valve 50 is provided in the approaching oil passage 48, and a pilot oil passage 52 extends between the separating oil passage 47 and the cylinder check valve 50 of the approaching oil passage 48. It is connected. The cylinder check valve 49 shown in FIG. 7 is not provided in the separating oil passage 47, and the pilot oil passage 51 is not provided.

As shown in FIGS. 1 to 6, the other end of the second link 22 extends from the lower part of the first link 21 in a direction away from the fuselage 1 along the longitudinal direction, so that the cylinder control valve 41 is When the hydraulic cylinder 31 is operated to the neutral position 41a and stopped, the other end of the first link 21 tends to swing away from the body 1 due to the weight of the body 1.

As a result, as shown in FIG. 9, the hydraulic cylinder 31 attempts to extend and the hydraulic oil in the oil chamber on the rod side of the hydraulic cylinder 31 attempts to leak through the approach oil passage 48, causing the hydraulic cylinder 31 to operate. Oil leakage is prevented by a cylinder check valve 50 in the approach oil passage 48.

As shown in FIG. 9, a pilot-operated cylinder check valve 55 is provided in the ascending oil passage 53, and a pilot oil passage 57 extends between the descending oil passage 54 and the cylinder check valve 55 of the ascending oil passage 53. It is connected. The cylinder check valve 56 shown in FIG. 7 is not provided in the descending oil passage 54, and the pilot oil passage 58 is not provided.

As shown in FIGS. 1 to 6, the other end of the second link 22 extends from the lower part of the first link 21 in a direction away from the fuselage 1 along the longitudinal direction, so that the cylinder control valve 42 is When the hydraulic cylinder 32 is stopped after being operated to the neutral position 42a, the other end of the second link 22 attempts to swing upward relative to the first link 21 (toward the downward direction of the aircraft 1) due to the weight of the aircraft 1. do.

As a result, as shown in FIG. 9, the hydraulic cylinder 32 attempts to contract and the hydraulic oil in the oil chamber on the bottom side of the hydraulic cylinder 32 attempts to leak through the rising oil passage 53, causing the hydraulic cylinder 32 to operate. Oil leakage is prevented by the cylinder check valve 55 of the ascending oil passage 53.

(Second alternative embodiment of the invention)
As shown in FIG. 10, a manually operated on-off valve 67 may be provided in a portion of the return oil path 30 between the return oil path check valve 35 and the connection portion of the unload oil path 37. The on-off valve 67 is operable to an open position 67a that communicates the return oil passage 30 and a closed position 67b that blocks the return oil passage 30.

In normal working conditions, the on-off valve 67 is operated to the open position 67a. In a state where the hydraulic pump 11 is driven by the engine 10 (a state where the return oil passage check valve 35 is opened by the pilot hydraulic oil branched from the supply oil passage 29), the cylinder control valves 41 of all the hydraulic units 28 , 42, 43 and the motor control valve 44 are operated to the neutral positions 41a to 44a, and all the hydraulic cylinders 31, 32, 33 and the hydraulic motor 34 are stopped. To maintain this state, the on-off valve 67 may be operated to the closed position 67b.

The on-off valve 67 may be configured to be electromagnetically operated. In this case, when the cylinder control valves 41, 42, 43 and motor control valves 44 of all the hydraulic units 28 are operated to the neutral positions 41a to 44a, the on-off valve 67 is automatically operated to the closed position 67b. Just configure it.
When at least one of the cylinder control valves 41, 42, 43 and motor control valve 44 of all the hydraulic units 28 is operated to a position other than the neutral positions 41a to 44a, the on-off valve 67 automatically moves to the open position 67a. It is only necessary to configure it so that it can be operated in a specific manner.

(Third alternative embodiment of the invention)
As shown in FIG. 7, when the hydraulic cylinder 31 is provided with cylinder check valves 49, 50 of the separating oil passage 47 and the approaching oil passage 48, and the pilot oil passages 51, 52, the hydraulic cylinder 32 is provided with the following: As shown in FIG. 9, the cylinder check valve 55 and pilot oil passage 57 of the ascending oil passage 53 may be provided, but the cylinder check valve 56 and pilot oil passage 58 of the descending oil passage 54 may be omitted.

(Fourth alternative embodiment of the invention)
As shown in FIG. 7, when the hydraulic cylinder 32 is provided with cylinder check valves 55, 56 of the ascending oil passage 53 and the descending oil passage 54, and pilot oil passages 57, 58, As shown in FIG. 9, the cylinder check valve 50 and pilot oil passage 52 of the approaching oil passage 48 may be provided, but the cylinder check valve 49 and pilot oil passage 51 of the separating oil passage 47 may be omitted.

(Fifth alternative embodiment of the invention)
In the hydraulic unit 28, the oil passages 59 and 60 for the hydraulic cylinder 33 are provided with cylinder check valves (see FIG. 7) similar to the motor check valves 63 and 64 (see FIG. A pilot oil passage (not shown) similar to the pilot oil passages 65, 66 (see FIG. 7) may be provided.

(Sixth alternative embodiment of the invention)
Three bending/stretching mechanisms 4 may be provided, or six bending/stretching mechanisms 4 may be provided.
In the bending and stretching mechanism 4, the hydraulic cylinder 31 and the first link 21 may be eliminated. According to this configuration, the second link 22 is supported by the body 1 so as to be able to swing up and down, and the hydraulic cylinder 32 is connected across the body 1 and the second link 22.
The engine 10 may be eliminated and the hydraulic pump 11 may be driven by an electric motor (corresponding to a drive section) (not shown).

(Seventh alternative embodiment of the invention)
The supply oil passage check valve 36 may be abolished and the return oil passage check valve 35 may be provided.
Both the supply oil passage check valve 36 and the return oil passage check valve 35 may be abolished.

The present invention can be applied to a work vehicle suitable for traveling on a work surface with many irregularities or a slope, and can also be applied to a work vehicle on which a worker can ride.

1 Aircraft body 4 Bending mechanism 5 Wheel 21 First link 22 Second link 31 Hydraulic cylinder (first hydraulic cylinder)
32 Hydraulic cylinder (second hydraulic cylinder)
34 Hydraulic motor 41 Cylinder control valve (first cylinder control valve)
41a Neutral position 42 Cylinder control valve (second cylinder control valve)
42a Neutral position 44 Motor control valve 44a Neutral position 47 Separating oil passage 48 Approaching oil passage 49 Cylinder check valve (Cylinder check valve of separating oil passage)
50 Cylinder check valve (cylinder check valve of approaching oil path)
53 Ascending oil passage 54 Descending oil passage 55 Cylinder check valve (cylinder check valve of ascending oil passage)
56 Cylinder check valve (cylinder check valve of descending oil path)
61 Forward rotation oil path 62 Reverse rotation oil path 63 Motor check valve (motor check valve for forward rotation oil path)
64 Motor check valve (motor check valve for reverse oil path)
P1 1st axis P2 2nd axis

Claims (9)

The aircraft and
a bending and stretching mechanism attached to multiple locations on the fuselage and extending from the fuselage;
traveling wheels supported by the extending end of the bending and stretching mechanism;
a hydraulic cylinder capable of bending and stretching the bending and stretching mechanism;
a cylinder control valve for supplying and discharging hydraulic oil to the hydraulic cylinder;
A cylinder check valve is provided that allows hydraulic oil to be supplied from the cylinder control valve to the hydraulic cylinder and prevents hydraulic oil from being discharged from the hydraulic cylinder when the cylinder control valve is operated to a neutral position. A working vehicle. a rising oil passage that supplies hydraulic oil from the cylinder control valve to the hydraulic cylinder for operating the hydraulic cylinder so that the bending mechanism causes the aircraft body to be lifted;
a descending oil passage that supplies hydraulic oil from the cylinder control valve to the hydraulic cylinder for operating the hydraulic cylinder so that the bending mechanism lowers the aircraft body;
The cylinder check valve is provided in the ascending oil passage and the descending oil passage,
When hydraulic oil is supplied from the cylinder control valve to the ascending oil passage, the cylinder check valve of the descending oil passage is opened by pilot hydraulic oil branched from the ascending oil passage;
The cylinder check valve of the ascending oil passage is operated to open by pilot operating oil branched from the descending oil passage when hydraulic oil is supplied from the cylinder control valve to the descending oil passage. work vehicle. The bending/stretching mechanism includes a first link having one end attached to the body so as to be swingable back and forth around a first axis along the left-right direction, and a first link having the other end extending downward from the body. a second link that is attached to the lower part of the first link so as to be swingable up and down about a second axis along the left-right direction, and whose other end side extends from the lower part of the first link along the front-rear direction; has,
the first hydraulic cylinder that swings the first link around the first axis;
a second hydraulic cylinder that swings the second link around the second axis;
a first cylinder control valve configured to supply and discharge hydraulic oil to and from the first hydraulic cylinder;
a second cylinder control valve for supplying and discharging hydraulic oil to and from the second hydraulic cylinder;
The ascending oil passage supplies hydraulic oil from a second cylinder control valve to a second hydraulic cylinder so that the other end of the second link is operated downward relative to the first link. an oil passage supplying the hydraulic cylinder,
The descending oil passage supplies hydraulic oil from a second cylinder control valve to a second hydraulic cylinder so that the other end of the second link is raised relative to the first link. an oil passage supplying the hydraulic cylinder,
Separation for supplying hydraulic oil from the first cylinder control valve to the first hydraulic cylinder to operate the first hydraulic cylinder so that the other end side of the first link is operated away from the aircraft body. oil road and
Hydraulic oil for operating the first hydraulic cylinder is supplied from the first cylinder control valve to the first hydraulic cylinder so that the other end side of the first link is operated toward the side approaching the aircraft body. It is equipped with an approaching oil road,
the cylinder check valve is provided in the approach oil passage;
When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, the cylinder check valve of the approaching oil passage is operated to open by pilot hydraulic oil branched from the separating oil passage. The work vehicle described in . The cylinder check valve is provided in the separation oil passage,
3. When hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, the cylinder check valve of the separation oil passage is operated to open by pilot hydraulic oil branched from the approaching oil passage. The work vehicle described in . a rising oil passage that supplies hydraulic oil from the cylinder control valve to the hydraulic cylinder for operating the hydraulic cylinder so that the bending mechanism causes the aircraft body to be lifted;
a descending oil passage that supplies hydraulic oil from the cylinder control valve to the hydraulic cylinder for operating the hydraulic cylinder so that the bending mechanism lowers the aircraft body;
the cylinder check valve is provided in the rising oil passage;
The cylinder check valve of the ascending oil passage is operated to open by pilot operating oil branched from the descending oil passage when hydraulic oil is supplied from the cylinder control valve to the descending oil passage. work vehicle. The bending/stretching mechanism includes a first link having one end attached to the body so as to be swingable back and forth around a first axis along the left-right direction, and a first link having the other end extending downward from the body. a second link that is attached to the lower part of the first link so as to be swingable up and down about a second axis along the left-right direction, and whose other end side extends from the lower part of the first link along the front-rear direction; has,
the first hydraulic cylinder that swings the first link around the first axis;
a second hydraulic cylinder that swings the second link around the second axis;
a first cylinder control valve configured to supply and discharge hydraulic oil to and from the first hydraulic cylinder;
a second cylinder control valve for supplying and discharging hydraulic oil to and from the second hydraulic cylinder;
The ascending oil passage supplies hydraulic oil from a second cylinder control valve to a second hydraulic cylinder so that the other end of the second link is operated downward relative to the first link. an oil passage supplying the hydraulic cylinder,
The descending oil passage supplies hydraulic oil from a second cylinder control valve to a second hydraulic cylinder so that the other end of the second link is raised relative to the first link. an oil passage supplying the hydraulic cylinder,
Separation for supplying hydraulic oil from the first cylinder control valve to the first hydraulic cylinder to operate the first hydraulic cylinder so that the other end side of the first link is operated away from the aircraft body. oil road and
Hydraulic oil for operating the first hydraulic cylinder is supplied from the first cylinder control valve to the first hydraulic cylinder so that the other end side of the first link is operated toward the side approaching the aircraft body. It is equipped with an approaching oil road,
the cylinder check valve is provided in the approach oil passage;
When hydraulic oil is supplied from the first cylinder control valve to the separating oil passage, the cylinder check valve of the approaching oil passage is operated to open by pilot hydraulic oil branched from the separating oil passage. The work vehicle described in . The cylinder check valve is provided in the separation oil passage,
When hydraulic oil is supplied from the first cylinder control valve to the approaching oil passage, the cylinder check valve of the separation oil passage is operated to open by pilot hydraulic oil branched from the approaching oil passage. The work vehicle described in . a hydraulic motor capable of rotationally driving the wheels;
a motor control valve for supplying and discharging hydraulic oil to the hydraulic motor;
A motor check valve is provided that allows hydraulic oil to be supplied from the motor control valve to the hydraulic motor and prevents hydraulic oil from being discharged from the hydraulic motor when the motor control valve is operated to a neutral position. The working vehicle according to any one of claims 1 to 7. a normal rotation oil path that supplies hydraulic oil for normal rotation of the hydraulic motor from the motor control valve to the hydraulic motor;
a reversing oil path for supplying hydraulic oil for reversing the hydraulic motor from the motor control valve to the hydraulic motor;
The motor check valve is provided in the forward rotation oil path and the reverse rotation oil path,
When hydraulic oil is supplied from the motor control valve to the forward rotation oil passage, the motor check valve of the reverse rotation oil passage is operated to open by pilot hydraulic oil branched from the normal rotation oil passage,
9. When hydraulic oil is supplied from the motor control valve to the reverse rotation oil passage, the motor check valve of the normal rotation oil passage is operated to open by pilot hydraulic oil branched from the reverse rotation oil passage. work vehicle.

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