JPH11141587A - Moving wheel brake releasing device of self-mobile type working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moving wheel brake-releasing device whereby brake application to each moving wheel by a moving wheel braking device is released using a simple configuration without resorting to an electric control, misoperation due to failure, etc., is precluded, and enhancement of the safety and cost-down are accomplished. SOLUTION: A moving wheel 13 is installed at the bottom of each supporting leg capable of expanding and contracting intalled on the front left and right and the rear left and right of the chassis of a vehicle, and the front supporting leg is equipped with a hydraulic motor 9 to drive the respective front moving wheel when pressure oil is supplied, while the rear supporting leg is equipped with a moving wheel braking device 22 to apply brake to the respective rear moving wheel when pressure oil is supplied. Each moving wheel braking device is equipped with a brake cylinder 23 to apply brake to the rear moving wheel with the pressure oil supplied from a pressure oil supply pipe 25, a pressure oil exhaust pipe 27 which exhausts the pressure oil from the brake cylinder and disengages the brake application to the rear moving wheel, and a pilot check valve 29 which puts the pressure oil exhaust pipe in communication or shuts it from communication, and when the front moving wheels are driven by the hydraulic motors the pilot pressure is fed to the pilot check valve via the pilot pressure supply pipe 34 so that the pressure oil exhaust pipe is put in communication to make it possible that the pressure oil is exhausted, and thus brake application to the rear moving wheels is disengaged.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving wheel brake release device for a self-propelled working vehicle having moving wheels for moving a chassis with respect to a ground surface when a pair of left and right support legs in front and rear of a chassis are extended. In addition, the present invention relates to a countermeasure for making it possible to release the braking of the moving wheel reliably and inexpensively.

[0002]

2. Description of the Related Art Conventionally, as disclosed in, for example, Japanese Utility Model Application Laid-Open No. 5-76929, work is performed at a high place by a bucket at the end of a boom which is provided so as to be able to swing up and down, extend and retract, and pivot with respect to a chassis. In a work vehicle or the like having a work device mounted on a chassis, four extensible support legs are provided behind the front, rear, left and right wheels to support the chassis (work vehicle itself) when extended with respect to a ground contact surface, A movable wheel is provided at the lower end of each of the support legs so that the chassis can move when extended, and in a state in which the chassis is supported by the support legs, the work at a high place is continuously performed by self-propelled movement of the movable wheel. I have.

In such a self-propelled work vehicle, moving wheel driving means such as a hydraulic actuator is provided on the front supporting leg of the front and rear supporting legs, and the moving wheel driving means is provided with a hydraulic actuator. Actuation drives the movable wheels of the front support legs. In this case, in general, since the work vehicle is braked by the rear wheels, when each support leg is extended, the front support leg is first extended to ground the front movable wheel to the ground, and In the non-operating state, that is, in a state where the braking is obtained by the rotation regulation of the front moving wheel, the rear support leg is extended to contact the front moving wheel with the ground. On the other hand, at the time of contraction of each support leg, the rear support leg is first contracted to bring the rear wheel into contact with the ground, and in a state where braking is obtained by the rear wheel, the front support leg is contracted to bring the front wheel to the ground. To ground.

[0004] However, an operator erroneously operates the front and rear support legs to extend and retract, and when each of the support legs is extended, the rear support leg is first extended to contact the rear movable wheel with the ground, If the front support leg is first contracted by contacting the front wheel with the ground when the support leg is contracted, there is a problem that the work vehicle is inadvertently self-propelled.

In order to prevent such erroneous operation by a worker, there has been developed a self-propelled work vehicle in which moving wheel braking is released by a moving wheel brake release device.
This moving wheel brake release device includes a moving wheel braking means for braking the moving wheel of the rear supporting leg on the rear supporting leg,
Even if the operator erroneously expands or contracts the support legs, the traveling wheel braking means prevents the work vehicle from inadvertently running with the braking force of the rear traveling wheel. In this moving wheel brake release device, the moving wheel braking means includes a brake cylinder for braking the rear moving wheel by supplying hydraulic pressure, an electromagnetic switching valve for switching between supply and discharge of hydraulic pressure to the braking cylinder, and the electromagnetic switching valve. A signal from a support leg grounding detector that detects that the front and rear support legs have touched the ground, and a support leg stroke detection that detects that the support leg has extended to the stroke end. Signals from the device are input to the control unit, and by controlling the switching of the electromagnetic switching valve based on these signals, while supplying hydraulic pressure to the brake cylinder to brake the rear moving wheels, The hydraulic pressure is discharged from the brake cylinder to release the braking of the rear moving wheel.

[0006]

However, when the braking of the moving wheel braking means is performed by electrical control as described above, there are the following drawbacks.

That is, since the moving wheel braking means is provided with electric devices such as an electromagnetic switching valve, a support leg grounding detector and a support leg stroke detector, the control at the time of braking release becomes complicated, and malfunctions due to failure or the like. For example, there is a possibility that a malfunction such as erroneous release of braking of the moving wheel when the moving wheel is not in contact with the ground may occur. Further, since such an electric device is expensive, the cost of the moving wheel braking means is increased.

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing, and it is an object of the present invention to release the braking of a moving wheel by a moving wheel braking means with a simple configuration without performing electrical control. By doing so, it is possible to prevent erroneous operation due to a failure or the like, to improve safety, and to reduce the cost of the moving wheel braking means.

[0009]

Means for Solving the Problems In order to achieve the above object, a solution according to the first aspect of the present invention is that a pair of support legs having a movable wheel at a lower end are provided so as to be able to extend and contract one by one at the front and rear of a chassis. A moving wheel brake release device of a self-propelled work vehicle configured such that the chassis is movably supported with respect to a ground contact surface by the moving wheels being in contact with the ground when the support legs are extended. I do. Further, one of the front and rear support legs is provided with moving wheel driving means for driving the moving wheel of one of the supporting legs by supplying the fluid, but not by stopping the supply of the fluid. Further, the other support leg is provided with a moving wheel braking means for braking the moving wheel of the other supporting leg by supplying the fluid and releasing the braking by stopping the supply of the fluid. When the supply of the fluid by the moving wheel drive unit is prohibited, the supply of the fluid by the moving wheel braking unit is performed to brake the moving wheel of the other support leg, thereby restricting the movement of the chassis. . on the other hand,
When the fluid is supplied to the moving wheel drive means, the moving wheel braking means inhibits the supply of the fluid, releases the braking of the moving wheel of the other support leg, and moves the chassis. It is what it was.

The solution taken by the invention according to claim 2 is as follows.
The moving wheel driving means and the moving wheel braking means according to the first aspect of the invention are specified. Specifically, the moving wheel driving means includes a fluid pressure motor for driving the moving wheel of one of the support legs by supplying a fluid. On the other hand, a fluid supply pipe for supplying a fluid to the moving wheel braking means, a telescopic brake cylinder extending so as to brake the moving wheel of the other support leg with the fluid supplied through the fluid supply pipe, A fluid discharge pipe for contracting the brake cylinder so as to release the brake of the moving wheel of the support leg and discharging the fluid from the brake cylinder, and a fluid discharge pipe provided on the fluid discharge pipe, and the fluid discharge pipe communicates with the fluid discharge pipe or A communication shield means for blocking fluid from being discharged, and a supply means connected between the communication shield means and the fluid pressure motor, the one of the support legs being supplied when the moving wheel is driven so that the fluid discharge pipe is in fluid communication with the fluid discharge pipe. And a fluid working tube for allowing the fluid from the fluid pressure motor to act on the communication shielding means.

According to the first and second aspects of the present invention, when the supply of fluid to the moving wheel driving means such as a fluid pressure motor is prohibited so as not to drive the moving wheels of one of the front and rear support legs. Is configured to brake the moving wheel of the other support leg by supplying the fluid by the moving wheel braking means, for example, to extend the brake cylinder by the fluid supplied through the fluid supply pipe to brake the moving wheel of the other support leg. ing.

On the other hand, when the fluid is supplied to the moving wheel driving means (fluid pressure motor) so as to drive the moving wheel of the one support leg, the supply of the fluid by the moving wheel braking means is prohibited. The moving wheel of the other supporting leg is released from braking, for example, the fluid supplied from the fluid pressure motor when the moving wheel of the one supporting leg is driven is applied to the communication shielding means in the middle of the fluid discharge pipe via the fluid working pipe. By connecting the fluid discharge pipe so that fluid can be discharged, the fluid from the brake cylinder is discharged through the fluid discharge pipe to contract the brake cylinder,
The brake of the moving wheel of the other support leg by the brake cylinder is released.

[0013] Thus, the braking of the moving wheel braking means can be easily released only by a fluid flow path such as a fluid supply / drain pipe to the moving wheel driving means and the moving wheel braking means, and the movement by complicated electric control. Abolition of brake release of wheels has been abolished.
Eliminates the need for electrical equipment such as the support leg grounding detector and the support leg stroke detector, and malfunctions due to failure of the electrical equipment, such as accidentally releasing braking of the moving wheel when the moving wheel is not on the ground Is prevented, and even if the operator operates the front and rear support legs in an incorrect order, braking by the moving wheels is reliably obtained, and safety is enhanced. In addition, the brake release of the moving wheel braking means is performed by the brake cylinder, the fluid supply pipe, the fluid discharge pipe, the communication shielding means, and the fluid working pipe, so that expensive electric equipment is not required and the cost is reduced.

Further, a solution taken by the invention of claim 3 is characterized in that the moving wheel driving means and the moving wheel braking means of the invention of claim 1 are specified. Specifically, the moving wheel driving means includes a fluid pressure motor for driving the moving wheel of one of the support legs by supplying a fluid. On the other hand, a fluid supply / discharge pipe for supplying / discharging fluid to / from the moving wheel braking means, a brake cylinder extending by a fluid supplied / discharged via the fluid supply / discharge pipe so as to brake the moving wheel of the other support leg, The brake cylinder is contracted by the fluid supplied and discharged through the fluid supply / discharge pipe so as to release the brake on the moving wheel of the other support leg, and the supply / discharge of the fluid supply / discharge pipe is interposed in the fluid supply / discharge pipe. A switching valve for switching the direction, and a fluid pressure which is connected between the switching valve and the fluid pressure motor and is supplied when the one of the support legs is driven by the moving wheel so that the supply / discharge direction of the fluid supply / discharge pipe is switched. And a fluid working tube for causing the fluid from the motor to act on the switching valve.

According to the third aspect of the present invention, the switching valve provided in the fluid supply / discharge pipe is used when the moving wheel of one of the support legs is driven by the moving wheel driving means (fluid pressure motor). The switching is performed by the fluid supplied from the moving wheel drive means via the fluid working tube, and the fluid supply / discharge direction in the fluid supply / discharge tube is reversed to release the braking of the moving wheel of the other support leg. However, the braking of the moving wheel braking means is released by a simple and inexpensive switching valve, thereby further improving safety and reducing costs.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 shows a self-propelled work vehicle provided with a moving wheel brake releasing device according to a first embodiment of the present invention, wherein 1 is a vehicle body, and 2 is mounted on the vehicle body 1 so as to be able to undulate and turn. A boom 1 as a working device is a support leg that supports the vehicle body 1 in a floating state and movably during work at a high place.

The vehicle body 1 comprises a chassis 1c, a carrier 1a provided on the chassis 1c, and a vehicle compartment 1b integrally connected to the chassis 1c. The normal traveling is performed by driving the four traveling wheels 4a and 4b, and the front wheel 4a becomes the wheel during normal traveling. In this case, when the parking brake (not shown) is operated while the vehicle body 1 is stopped, braking by the rear wheel 4b is obtained.

The boom 2 includes a turning column 2a rotatably supported on the chassis 1c about a vertical axis V1.
A telescopic tube 2c rotatably connected to the upper end of the turning column 2a about a horizontal axis H1 and rotatably connected by a hoisting cylinder 2b, and a work bucket 2d provided at the tip of the telescopic tube 2c When the worker rides on the bucket 2d to extend the undulating cylinder 2b, the bucket 2d
It rises relatively to c.

The support leg 3 includes a pair of left and right front support legs 3a (one support leg) provided on the front side of the chassis 1c, and a pair of left and right rear support legs 3b (the other) provided on the rear side of the chassis 1c. Support legs).

Each of the front support legs 3a (since they have the same structure, reference numerals are given only to those on the left side shown in FIG. 3, and only different reference numerals are given to those on the right side in parentheses, and description thereof is omitted. 3) includes a jack portion 5 as shown in detail in FIG. A bracket 6 is held at the lower end of the jack portion 5 so as to be rotatable around a vertical axis V2.
(7R) rotates. A front moving wheel 8 is held by the bracket 6 so as to be rotatable about a horizontal axis H2, and the front moving wheel 8 is configured as a steering wheel at the time of working at a high place. Further, a hydraulic motor 9 (fluid pressure motor) is mounted on the bracket 6 as moving wheel driving means for driving the front moving wheel 8 to rotate. When the hydraulic motor 9 is not driven, the rotation of the front moving wheel 8 is restricted and braking is obtained.
The front moving wheel 8 is formed of a solid rubber tire so that the vehicle body 1 does not tilt due to the occurrence of puncture. Although FIGS. 3 and 4 show only the left front support leg 3a, the right support leg is configured similarly to the left support leg.

Each of the jack portions 5 has an inclined axis X1 which is disposed vertically with respect to the chassis 1c and in which the bottomed cylindrical outer cylinder 5a is inclined so as to be inclined downward toward the front. And is fixed to the chassis 1c. A rectangular cylindrical inner cylinder 5b is slidably inserted into the outer cylinder 5a. The inner cylinder 5b houses a cylinder 5c having one end connected to the lower end of the inner cylinder 5b and the other end connected to the upper end of the outer cylinder 5a. A boss 5d for holding the bracket 6 is fixed to a lower end of the inner cylinder 5b. Although not shown, a disk swelling inward (in the direction of the horizontal axis H2) from the rim of the wheel of the front moving wheel 8 is rotatably supported on the bracket 6 via a bearing. In each of the jack sections 5, the inner cylinder 5b protrudes from the outer cylinder 5a by the extension operation of the cylinder 5c, and the front moving wheel 8 is pushed down diagonally downward to float the vehicle body 1 (see FIGS. 3 and 3). 4, the inner cylinder 5b is immersed in the outer cylinder 5a by the contraction operation, and the traveling wheels 4a, 4b are brought into the stowed state (the state shown by the solid line in FIG. 4). It has become so.

Each of the brackets 6 is provided with a corresponding one of the front moving wheels 8.
A cover 6a that covers the upper portion while leaving a ground portion of the cover, and a shaft portion 6b that projects upward from the upper surface of the cover 6a.
The shaft portion 6b is held rotatably about the vertical axis V2 by the boss portion 5d. An arm member 5e projecting obliquely rearward from the front movable wheel 8 inside the chassis 1c is fixed to the boss 5d, and one end of the hydraulic cylinder 7L (7R) is connected to the arm member 5e. And the other end is connected to the upper surface of the cover 6a at a position away from the vertical axis V2.
When the hydraulic cylinder 7L (7R) is in the neutral position, the front moving wheel 8 is held in the straight traveling direction of the vehicle body 1, and when the hydraulic cylinder 7L (7R) is reduced from the neutral position, the front moving wheel 8 faces leftward with respect to the vehicle body 1. When the front moving wheel 8 is extended in the opposite direction, the front moving wheel 8 is steered rightward with respect to the vehicle body 1. Also, the cover 6a of each of the brackets 6
The hydraulic motors 9 are respectively mounted on the inner side portions of the vehicle body, and the hydraulic motors 9 directly rotate the front moving wheels 8.

On the other hand, each of the rear support legs 3b has a jack portion 11, a bracket 12 fixed to a lower end of the jack portion 11, and a rear side held by the bracket 12 so as to be rotatable about a horizontal axis H3. And a moving wheel 13. The rear moving wheel 13 is connected to the front moving wheel 8.
Similarly to the above, it is formed of a solid rubber tire in which the vehicle body 1 does not tilt due to the occurrence of puncture. Each of the brackets 12 includes a cover 12a (see FIG. 2) that covers an upper portion of the rear movable wheel 13 except for a ground contact portion.

The jack portion 11 is provided with the front support leg 3.
The outer cylinder 11a has a bottomed square cylindrical shape and is fixed to the vehicle body 1 and has an inclined axis X2 inclined so as to be inclined downward toward the rear in symmetry with the jack portion 5 of FIG. A rectangular cylindrical inner cylinder 11b is slidably inserted into the outer cylinder 11a. The inner cylinder 11b houses a cylinder 11c having one end connected to the lower end of the inner cylinder 11b and the other end connected to the upper end of the outer cylinder 11a. The extension and contraction of the cylinder 11c allows the vehicle body 1 to be converted into the floating and stored state.

As shown in FIG. 2, the inner cylinder 11b
A boss 11 for holding the bracket 12 is provided at a lower end of the boss 11.
d is provided. At the tip of the boss 11d, a disk 14b bulging inward (toward the boss 11d) from the rim 14a of the wheel 14 of the rear moving wheel 13 is mounted on the bearing 1.
5, and is rotatably supported. In addition, 16 in FIG.
Is a bearing cover that covers the bearing 15 from outside the vehicle body.

At the upper end of the cover 12a of the rear support leg 3b, there is provided an opening 12b having a substantially rectangular shape in plan view. At the front and rear edges of the opening 12b, the lower end of a mounting bracket 21 having a substantially hat-shaped cross section is mounted. ing. A moving wheel braking device 22 is mounted on the mounting bracket 21 as moving wheel braking means for braking the rear moving wheel 13. As shown in FIG. 1, the moving wheel braking device 22 includes a braking cylinder 23 that extends and contracts in the axial direction extending in the vertical axis direction. The brake cylinder 23 is partitioned by a piston 23a into a head-side chamber 23b and a rod-side chamber 23c. The head-side chamber 23b has one end connected to the other end of a pressure oil supply pipe 25 connected to a hydraulic pump 24, and one end connected to a reservoir. The other end of the pressure oil discharge pipe 27 connected to the tank 26 is connected to each other. An unload valve 28 is provided in the middle of the pressure oil supply pipe 25, and when the oil pressure of the head side chamber 23b of the brake cylinder 23 becomes higher than a set pressure, the pressure oil of the head side chamber 23b is supplied to the reservoir tank 26. Reflux. In the middle of the pressure oil discharge pipe 27, a pilot check valve 2 opened by the action of pilot pressure is provided.
9 are interposed.

The rod 2 of the brake cylinder 23
At the tip of 3d, a brake pad 32 is provided via a stay 31.
Is installed. The brake pad 32 has a substantially rectangular shape slightly smaller than the opening 12b of the bracket 12 in plan view, and the rod 23d is compressed by the pressure oil supplied from the pressure oil supply pipe 25 to the head side chamber 23b of the brake cylinder 23. By being extended, the upper end of the outer peripheral portion of the rear moving wheel 13 is pressed through the opening 12b. Further, the rod side chamber 23c of the brake cylinder 23
The compression spring 33 for urging the rod 23d in the contracting direction is compressed. The pilot check valve 29 is connected to a pilot pressure supply pipe 34 as a fluid working pipe for supplying pilot pressure from the hydraulic motor 9 to the pilot check valve 29.
A part of the pressure oil supplied to the hydraulic motor 9 via the supply / discharge pipe 35 so as to drive the front moving wheel 8 from a drive pump (not shown) is supplied to the pilot pressure supply pipe 34. Is applied to the pilot check valve 29 as a pilot pressure via the pilot pressure supply pipe 34, whereby the pilot check valve 29 is opened. The pilot check valve 29 and the pilot pressure supply pipe 34 constitute a communication shielding means 36. In this case, the hydraulic cylinder 24 controls the brake cylinder 2
3 is set to 140 kg / cm ² , whereas the hydraulic oil 9 is supplied to the pilot pressure supply pipe 3 from the hydraulic motor 9.
Part of the pressure oil supplied to No. 4, that is, the pilot pressure is 175
The pilot pressure is set to kg / cm ^2, and the pilot pressure of the high hydraulic pressure acts on the pilot check valve 29 effectively.

Next, the operation of the self-propelled work vehicle having the above configuration will be described.

When performing high-altitude work, the parking brake is operated to bring the rear wheel 4b into a braking state, and then the front moving wheel 8 is first grounded by the jack portion 5 of the front support leg 3a to lift the front wheel 4a. In the state where the braking by the front moving wheel 8 is obtained by the rotation regulation when the hydraulic motor 9 is not driven, the rear moving wheel 13 is grounded by the jack portion 11 of the rear support leg 3b to lift the rear wheel 4b. The vehicle body 1 is supported by the front and rear support legs 3a and 3b (both front and rear moving wheels 8 and 13), and the bucket 2d is raised by the up and down movement of the boom 2 to perform work at a high place. Then, at the time of working at a high place, the vehicle body 1 is driven at an extremely low speed (for example, by driving the hydraulic motor 9).
1.5 Km / h), the vehicle body 1 can be moved in the left-right direction by operating a pair of hydraulic cylinders 7L, 7R to steer the front moving wheels 8, 8. Can also be moved.

When normal running is performed from this state, the rear wheel 4b is first landed by the jack portion 11 of the rear support leg 3b, and braking by the rear wheel 4b is obtained.
By arranging the front wheel 4a by the jack portion 5 of the front support leg 3a, the vehicle body 1 is supported by the front and rear wheels 4a, 4b with the front and rear support legs 3a, 3b in the stowed state, and normal traveling can be performed. Become.

Therefore, in the first embodiment, when the hydraulic oil is not supplied to the hydraulic motor 9, the rear moving wheel 13 applies the hydraulic oil to the head side chamber 23 b of the brake cylinder 23 of the moving wheel braking device 22. When the pressure oil is supplied through the supply pipe 25, the rod 23d is extended and the brake pad 3
2 is pressed against the upper end of the outer peripheral portion of the rear moving wheel 13 to perform braking, and when hydraulic oil is supplied to the hydraulic motor 9, the hydraulic oil supplied to the hydraulic motor 9 is supplied to the pilot pressure supply pipe 3.
Pilot check valve 29 as pilot pressure through 4
The pilot check valve 29 is opened, the pressure oil discharge pipe 27 communicates, and the head side chamber 2 of the brake cylinder 23 is actuated.
By discharging the pressure oil of 3b into the reservoir tank 26,
The rod 23d is contracted by the urging force of the compression spring 33, and the brake pad 32 is separated from the outer peripheral portion of the rear moving wheel 13 to release the braking. Therefore, a pressure oil supply / discharge pipe 2 for supplying / discharging pressure oil to / from the head side chamber 23b of the hydraulic cylinder 23
The braking of the rear moving wheel 13 can be released only by the hydraulic oil flow path such as the pilot pressure supply pipe 34 for applying the pilot pressure to the pilot check valve 29, 5, 27 and the rear moving by complicated electric control. The release of braking of the wheel 13 is abolished, and electric devices such as an electromagnetic switching valve, a support leg grounding detector, and a support leg stroke detector are not required. Malfunction due to failure or the like, for example, the front and rear moving wheels 8 and 13 are not operated. In a state where the front wheel 4a and the rear movable wheel 13 are not in contact with the ground, or in a state where the rear movable wheel 13 is in contact with the ground, malfunction such as release of braking of the rear movable wheel 13 is prevented, and safety can be improved.

In addition, since the braking of the moving wheel brake device 22 is released by the brake cylinder 23, the pressure oil supply pipe 25, the pressure oil discharge pipe 27, and the communication shielding means 36, expensive electric equipment is eliminated and the cost is reduced. Can be achieved.

Next, a second embodiment of the present invention will be described with reference to FIG.

In this embodiment, the configuration of the moving wheel braking device is changed.

That is, in the present embodiment, as shown in FIG. 5, the moving wheel braking device 41 includes a braking cylinder 42. The brake cylinder 42 is divided into a head side chamber 42b and a rod side chamber 42c by a piston 42a. The other end of the first pipe 43, one end of which is connected to the hydraulic pump 24, is connected to the head side chamber 42b, and the second end of which is connected to the reservoir tank 26, one end of which is connected to the rod side chamber 23c.
A pipe 44 is connected. The first and second pipes 4
A switching valve 45 is provided midway between 3 and 44. The switching valve 45 is connected to a first position (the left position in FIG. 5) where the first pipe 43 can supply the pressurized oil and the second pipe 44 can discharge the pressurized oil to the brake cylinder 42, and to the brake cylinder 42. On the other hand, the first pipe 43 is made capable of discharging pressure oil and the second pipe 4
4 is provided with a spool 45a that moves so as to switch to a second position (right position in FIG. 5) in which pressure oil can be supplied.
An operating hydraulic pressure supply pipe 46 as a fluid working pipe is connected between the hydraulic motor 9 and the switching valve 45. The working hydraulic supply pipe 46 is connected to the front moving wheel 8 by a drive pump.
Is supplied to the hydraulic motor 9 via the supply / discharge pipe 35 so as to drive the hydraulic pump 9, and a part of the hydraulic pressure oil is supplied to the spool of the switching valve 45 via the working hydraulic supply pipe 46. By acting on the spool 45a, the spool 45a moves.

When the hydraulic motor 9 is driven, the switching valve 45 is connected to the hydraulic motor 9 via the operating hydraulic supply pipe 46.
When the operating pressure oil acts on the spool 45a, the spool 45a moves to switch the switching valve 45 from the first position to the second position, whereby the switching valve 45 is switched between the brake cylinder 42 and the switching valve 45. The flow direction of the pressure oil in the first and second pipes 43 and 44 is reversed, and the pressure oil from the hydraulic pump 24 is supplied to the head side chamber 42 b of the brake cylinder 42 by the first pipe 43.
And the pressure oil in the rod-side chamber 42c is returned to the reservoir tank 26 through the second pipe 44, whereby the rod 42d of the brake cylinder 42 contracts, and the rear moving wheel 13
The brake pad 32 separates from the outer peripheral portion of the rear wheel, and the rear moving wheel 13 is released from braking. On the other hand, when the operation pressure oil of the hydraulic motor 9 does not act on the spool 45a of the switching valve 45 due to the stop of the driving of the hydraulic motor 9, the spool 45
a, the switching valve 45 is held at the first position, the rod 42d is held in the extended state, and the brake pad 32 is pressed against the upper end of the outer peripheral portion of the rear side moving wheel 13 so that the rear side moving wheel 13 Brakes.

Therefore, in the second embodiment, the switching valve 45 interposed between the brake cylinder 42 and the hydraulic pump 24 allows the hydraulic motor 9 to supply the operating hydraulic supply pipe only when the front moving wheel 8 is driven. When the spool 45a is moved to the second position by moving the spool 45a by the operating pressure oil supplied through the port 46, the pressure oil in the first and second pipes 43 and 44 between the brake cylinder 42 and the switching valve 45 is changed. Is reversed, the hydraulic oil from the hydraulic pump 24 is supplied to the head side chamber 42b of the brake cylinder 42 through the first pipe 43, and the hydraulic oil in the rod side chamber 42c is returned to the reservoir tank 26 through the second pipe 44. As a result, the rod 42d of the brake cylinder 42 contracts, the brake pad 32 separates from the outer peripheral portion of the rear moving wheel 13, and the rear moving wheel 13 is released from braking. Since the rod 42d of the brake cylinder 42 is contracted and the brake pad 32 is separated from the outer peripheral portion of the rear moving wheel 13 to release the braking of the rear moving wheel 13, the structure is simple and inexpensive. By the switching valve 45,
Further improvement in safety and cost reduction can be achieved.

It should be noted that the present invention is not limited to the above embodiments, but includes various other modifications. That is, in each of the above embodiments, the moving wheel braking device 2
Although the rear moving wheel 13 is braked and released by steps 2 and 41, the moving wheel braking device is provided on the bracket of the cover of the front support leg, and the moving wheel braking device controls the braking and releasing of the front moving wheel. It may be performed.

Further, in each of the above embodiments, the hydraulic pump 24 for supplying hydraulic oil to the head side chamber 23b (42b) of the brake cylinder 23 (42), and the drive pump for supplying hydraulic pressure to the hydraulic motor 9 are provided. Are provided separately, however, a single pump may be used to supply hydraulic oil or hydraulic oil to the head side chamber of the brake cylinder and the hydraulic motor, respectively. In this case, the operating pressure oil supplied to the hydraulic motor is set to be higher than the pressure oil supplied to the head side chamber of the brake cylinder.

Further, in each of the above embodiments, the front moving wheel 8 can be steered in the left-right direction with respect to the vehicle body 1, but the rear moving wheel can be steered in the left-right direction with respect to the vehicle body. May be.

Further, in each of the above embodiments, the boom 2 is configured so as to be able to be raised and lowered, and can be turned. However, it is needless to say that the working device may be configured so that the boom can be raised, contracted and turned. It goes without saying that any working device that performs work in a place is applied.

[0043]

As described above, according to the moving wheel brake releasing device for a self-propelled work vehicle according to the first and second aspects of the present invention, braking is performed by supplying the fluid through the fluid supply pipe of the moving wheel braking means. While the cylinder is extended to brake the moving wheel, the supply fluid from the moving wheel driving means acts on the communication blocking means of the moving wheel braking means via the fluid working tube when the moving wheel is driven, and the fluid discharge pipe from the braking cylinder is moved. Since the brake cylinder is contracted by the discharged fluid to release the braking of the moving wheel, the braking of the moving wheel can be simply and inexpensively released only by the fluid flow path to the moving wheel driving means and the moving wheel braking means. Thus, safety can be improved by preventing malfunction due to a failure or the like, and cost can be reduced with the elimination of expensive electric equipment.

According to the third aspect of the present invention, when the moving wheels are driven, the fluid supplied from the fluid pressure motor is applied to the switching valve via the fluid working tube when the moving wheels are driven. By switching the supply / discharge direction of the fluid supply / drain pipe, the braking of the moving wheel by the moving wheel braking means is released, and further simplification and cost reduction by the switching valve achieve further improvement in safety and cost reduction. it can.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram of a moving wheel braking device according to a first embodiment.

FIG. 2 is a partially cutaway enlarged view showing a rear support leg.

FIG. 3 is a partially cutaway enlarged view showing a front support leg.

FIG. 4 is a side view of the self-propelled work vehicle.

FIG. 5 is a hydraulic circuit diagram of a moving wheel braking device according to a second embodiment.

FIG. 6 is a partially cutaway enlarged view showing a rear support leg.

[Explanation of symbols]

 1c Undercarriage 3 Support leg 3a Front support leg (one support leg) 3b Rear support leg (the other support leg) 8,13 Moving wheel 9 Hydraulic motor (moving wheel driving means) 22,41 Moving wheel braking device (moving wheel Brake means) 23, 42 Brake cylinder 25 Pressure oil supply pipe 27 Pressure oil discharge pipe 34 Pilot pressure supply pipe (fluid working pipe) 36 Communication shielding means 43, 44 First and second pipes (Fluid supply / discharge pipe) 45 Switching valve 46 Working hydraulic supply pipe (fluid working pipe)

Claims (3)

[Claims] 1. A pair of support legs having a movable wheel at a lower end thereof are provided so as to be able to expand and contract in a pair at right and left sides of a chassis, and when the respective support legs extend, each of the movable wheels comes into contact with the ground so that the chassis becomes a ground contact surface. A moving wheel brake release device for a self-propelled work vehicle configured to be movably supported, wherein one of the front and rear supporting legs has a moving wheel of the one supporting leg. Moving wheel driving means is provided for driving by supplying the fluid, but not for driving by stopping the supply of the fluid, and the other supporting leg brakes the moving wheel of the other supporting leg by supplying the fluid, Moving wheel braking means for releasing the braking by stopping the supply of the fluid is provided. When the supply of the fluid by the moving wheel driving means is prohibited, the supply of the fluid by the moving wheel braking means is performed and the other support is provided. The moving wheel of the leg When the fluid is supplied to the moving wheel driving means, the supply of the fluid to the moving wheel braking means is prohibited and the other A moving wheel of a self-propelled work vehicle, wherein the moving wheel of the supporting leg is released from braking and the chassis is moved. 2. The moving wheel driving means includes a fluid pressure motor for driving the moving wheel of the one support leg by supplying fluid, while the moving wheel braking means includes a fluid supply pipe for supplying fluid. A telescopic brake cylinder that extends to brake the moving wheel of the other support leg with the fluid supplied through the fluid supply pipe, and the brake cylinder that releases the braking of the moving wheel of the other support leg. A fluid discharge pipe for contracting and discharging fluid from the brake cylinder, a communication shielding means provided on the fluid discharge pipe, for communicating the fluid discharge pipe so as to be able to discharge the fluid, or for shielding the fluid discharge pipe so as not to be discharged, and the communication shielding means And the fluid pressure motor, the fluid shielding pipe being connected to the fluid discharge pipe so that the fluid discharge pipe can communicate with the fluid discharge pipe. Self-propelled work vehicle moving wheel brake releasing device according to claim 1, characterized in that a fluid working tube to act on. 3. The moving wheel driving means includes a fluid pressure motor for driving the moving wheel of the one support leg by supplying a fluid, while the moving wheel braking means includes a fluid supply / discharge for supplying / discharging the fluid. A pipe, a brake cylinder extending by a fluid supplied and discharged through the fluid supply / discharge pipe so as to brake the moving wheel of the other support leg, and a brake cylinder interposed in the fluid supply / discharge pipe, A switching valve for contracting the brake cylinder by a fluid supplied / discharged through the fluid supply / discharge pipe so as to release the brake of the moving wheel to switch the supply / discharge direction of the fluid supply / discharge pipe; and the switching valve and the fluid pressure motor And a fluid working tube connected to the fluid supply / discharge tube for causing a fluid from a fluid pressure motor supplied at the time of driving the moving wheel of the one support leg to switch the supply / discharge direction of the fluid supply / discharge tube to act on the switching valve. The self-propelled work vehicle according to claim 1, comprising: Movement wheel braking release device.