JP2501336Y2 - Work vehicle braking system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a braking device for a work vehicle.

[Conventional technology]

Some wheel loaders, which are one of the work vehicles, include a braking device as shown in FIG. 4, for example.
That is, during the start of the engine (10), the hydraulic oil is supplied from the pump (25) to the oil chamber (R), and the piston (23) moves away from the braking friction plate (21) to the right side of the drawing and the friction plate. (21) is not pressed. When the brake pedal (26) is depressed in this state, the brake piston (24) moves to the right on the paper surface and presses the friction plate (21).
A braking state is obtained.

On the contrary, when the engine (10) is stopped, the hydraulic oil escapes from the oil chamber (R), so that the piston (23) presses the friction plate (21) to the left in the drawing by the urging force of the spring (22). That is,
By stopping the engine (10), the braking state can be automatically obtained without stepping on the brake pedal (26).

With the above structure, it is possible to prevent the braking state from being obtained even when the engine (10) is stopped. That is, the bolt (29) (corresponding to a screw member) is removed from the casing (20), and the spacer (31) sandwiched between the bolt (29) is removed.
Remove. When the bolt (29) is screwed in again, the rod (28) is pushed rightward on the paper surface by the bolt (29), and the piston (23) is moved rightward on the friction plate by the rod (28). It is pushed and held to a position where (21) is not pushed.

[Problems to be solved by the device]

In the above structure, the bolt (29) must be removed once when switching between a state where braking is obtained and a state where braking is not obtained when the engine (10) is stopped. Therefore,
If the bolt (29) is removed while the pressure inside the oil chamber (R) is not sufficiently reduced, the rod (28) will be pushed out of the casing (20) by the pressure inside the oil chamber (R) and will fall out. .

Here, the present invention aims to prevent the above situation.

[Means for solving the problem]

A feature of the present invention is that the braking device for a work vehicle as described above is configured as follows. In other words, a stepped rod that comes into contact with the piston and can be pushed to the brake release side and a screw member that comes into contact with the opposite end of the rod and that can be pushed and held to the brake release side are provided. In that, by contacting the stepped portion of the rod, there is provided a contacting portion that moves in a direction away from the piston and prevents the rod from falling out of a member slidably provided with the rod, The action and effect are as follows.

[Action]

If the rod that operates the piston to the brake release side has the stepped structure as described above, even if the rod is pushed out by the internal pressure when the screw member is removed, the stepped part of the rod will contact the contact part. Then, the rod is stopped so as not to come out of the member provided with the rod.

Further, in the conventional structure shown in FIG. 4, the rod (28) has a round bar shape having the same diameter at both front and rear ends, but in the present invention, it may be constructed as a stepped rod having a partly different diameter. It can be easily processed.

[Effect of device]

As described above, it is possible to prevent the rod for pushing the piston toward the brake release side from dropping out of the member provided with the rod, and to prevent the rod from being lost.

Further, since it can be easily carried out only by processing the rod into a step, the manufacturing cost is not increased.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 3, a front vehicle body (2) having a pair of left and right front wheels (1) and a rear vehicle body (4) having a pair of left and right rear wheels (3) are arranged around a vertical axis (Y). It is swingably connected,
A steering cylinder (5) is provided between the front and rear vehicle bodies (2) and (4) to form a traveling vehicle body. The front vehicle body (2) is provided with a shovel (7) supported by a pair of left and right arms (6) so as to be able to move up and down, a lift cylinder (8) and a tilt cylinder (9) for driving these, and a rear portion. An engine (10), a seat (11) and a steering wheel (12) are provided on the vehicle body (4) to form a wheel loader which is one of the working vehicles.

In this wheel loader, as shown in FIGS. 2 and 3, a variable displacement hydraulic pump (13) driven by an engine (10) and a hydraulic pressure driven by hydraulic oil from the hydraulic pump (13). It is provided with a hydrostatic continuously variable transmission system composed of a motor (14). Then, the power from the hydraulic motor (14) is transmitted to the output shaft (16) by the three sets of transmission gears (18) in the transmission case (15) and is transmitted to the differential device (3a) for the rear wheel (3). At the same time, it is transmitted to the differential device (1a) of the front wheel (1) via the transmission shaft (17).

Next, the braking device provided on the output shaft (16) will be described. As shown in FIG. 2, a friction plate (21) for braking is attached to the output shaft (16), and a piston (23) capable of pressing the friction plate (21) from the right side of the drawing is provided. A spring (22) for urging the piston (23) toward the pressing side of the friction plate (21) is provided. On the other hand, a brake piston (24) capable of pressing the friction plate (21) from the left side of the drawing is provided on the left side of the friction plate (21) in the drawing, and the brake piston (24) is depressed by depressing the brake pedal (26).
A master cylinder (27) for supplying hydraulic oil is provided.

In the state shown in FIG. 2, the engine (10) is operating,
The hydraulic oil from the pump (25) driven by the engine (10) is being supplied to the oil chamber (R) between the piston (23) and the casing (20). That is, the piston (23) is separated from the braking friction plate (21) to the right in the drawing and is not in a state of pressing the friction plate (21). When the brake pedal (26) is stepped on in this state, the hydraulic oil from the master cylinder (27) causes the brake piston (24) to move to the right on the paper surface and press the friction plate (21). can get.

On the contrary, when the engine (10) is stopped, the hydraulic oil escapes from the oil chamber (R), so that the piston (23) presses the friction plate (21) to the left in the drawing by the urging force of the spring (22). That is,
By stopping the engine (10), the braking state can be automatically obtained without stepping on the brake pedal (26).

With the above structure, it is possible to prevent the braking state from being obtained even when the engine (10) is stopped. This is a case where the wheel loader is towed by another vehicle. Next, this structure will be described. As shown in FIGS. 1 and 2, a stepped rod (28) having a large diameter on the piston (23) side is slidably provided in the casing (20), and
A bolt (29) (corresponding to a screw member) is attached to the left side of the rod (28) in the drawing. An oil seal (19) is attached to the large diameter side of the rod (28). That is,
The casing (20) is provided with a rod (28) slidably.

The state shown in FIG. 1 is a state in which the hydraulic oil from the pump (25) is being supplied into the oil chamber (R), and the rod (28) is pushed to the left side of the drawing by the pressure of this hydraulic oil and the bolt He is in contact with (29). When the engine (10) is stopped in this state, hydraulic oil escapes from the oil chamber (R) and the spring (22)
The piston (23) is moved to the left side of the drawing by the urging force of, and presses the friction plate (21) to obtain a braking state.

When the bolt (29) is removed in this state or when the engine (10) is stopped, the rod (28) is pushed to the left side of the drawing by the pressure remaining in the oil chamber (R). Also, the step (28a) of the rod (28) has a casing (2
0) contact the contact part (20a) and cannot move further to the left in the plane of the drawing, that is, from the casing (20) to the rod (2
8) does not fall out.

After that, when the spacer (31) is removed and only the bolt (29) is screwed in again, the rod (28) is pushed rightward on the paper surface by the bolt (29) and comes into contact with the piston (23). Then, by further screwing the bolt (29), the piston (23) can be stopped at the position shown in FIG. 1 by the rod (28). Therefore, even if the engine (10) is stopped in this state, the piston (23) does not move,
The braking state cannot be obtained.

In the embodiment described above, the step portion (28a) and the contact portion (20
a) may be a tapered surface.

It should be noted that reference numerals are added to the claims of the utility model for convenience of comparison with the drawings, but the present invention is not limited to the structure of the accompanying drawings by the entry.

[Brief description of drawings]

The drawings show an embodiment of a braking system for a work vehicle according to the present invention,
1 is an enlarged cross-sectional view of the vicinity of the rod in the braking device, FIG. 2 is a cross-sectional view of the vicinity of the braking device, FIG. 3 is an overall side view of the wheel loader, and FIG. 4 is a cross-sectional view of the vicinity of the braking device in the conventional structure. . (10) …… Engine, (20) …… Member, (20a) …… Abutment part, (22) …… Spring, (23) …… Piston, (25)…
… Pump, (28)… Rod, (28a)… Rod step, (29)… Screw member.

Claims (1)

(57) [Scope of utility model registration request] 1. A brake release side is operated by hydraulic oil from a pump (25) driven by the power of an engine (10),
A braking device for a working vehicle, comprising a piston (23) for braking, which is operated to the braking side by the urging force of a spring (22) when the hydraulic oil is not supplied, the braking device being in contact with the piston (23). The stepped rod (28) that can be pushed to the brake release side and the screw member (29 that can be pushed and held to the brake release side by contacting the opposite end of this rod (28). ) And abutting against the stepped portion (28a) of the rod (28), the rod (28) is slidably moved from the member (20) which moves in a direction away from the piston (23). Abutment (20) that prevents the rod (28) from falling out.
Braking device for work vehicles equipped with a).