JPH0352223Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a brake device for a hydrostatically driven traveling work vehicle.

[Conventional technology]

Conventionally, work vehicles driven by hydrostatic hydraulic drive are:
For example, various types of snow removal vehicles are known, such as crane trucks, bucket hoes, and snow removal vehicles.

In Figures 2 and 3, 1 is a variable displacement hydraulic pump that is operated by the rotation of the engine 2, and its left discharge ports 1A, 1B and right discharge port 1.
High pressure hoses 3A, 3B, and 3 are attached to C and 1D, respectively.
C and 3D are connected. High pressure hose 3A, 3B
The high pressure hose 3 is connected to the constant capacity left hydraulic motor 4A.
C and 3D are connected to a constant displacement right hydraulic motor 4B. Right side hydraulic motor 4A, left side hydraulic motor 4
Sprockets 5A and 5B are connected to B via drive shafts S _A and S _B , respectively, and the left and right crawlers 6, 6 are driven by the rotation of these sprockets 5A, 5B, and the snowplow runs. It's summery.

When the pump operating lever 7 in the driver's cab H of the snowplow is set to the forward or reverse position (the state shown by the two-dot chain line), the pressure oil flows through the high-pressure hoses 3A, 3C or the high-pressure hoses 3B, 3D to the left hydraulic motor 4A. , is supplied to the right hydraulic motor 4B, which rotates forward or reverse to move the snowplow forward or backward, and when the pump operating lever 7 is placed in the neutral position, no pressure oil is supplied and the snowplow stops.

FIG. 4 shows an engine rotation switching device 8 that drives the hydraulic pump 1, and a pedal section 18 of a foot brake device 16 (described later) that stops the snowplow from running.
and are provided in the driver's cab H, respectively.

The engine rotation switching device 8 is connected to an accelerator lever 9 rotatably supported on the cab floor F around a rotation axis 9A, a bracket 10 having a sawtooth tooth profile 10A, and one end side of the accelerator lever 9. A first rod 11 that moves approximately linearly by rotation of the lever 9 and is attached to the cab floor F, a wire 12 whose one end is connected to the first rod 11, and a wire 12 connected to the other end 12A of the wire 12 and attached to the engine 2. movable second
It is composed of a rod 13, a tension spring member 14 connected to the second rod 13, and a rotation bracket 15 that is ring-connected to the tip of the second rod 13 and rotates around a rotation axis 15A. The accelerator lever 9 includes a lever main body 9B, a sub-bracket 9F that is rotatably attached to the lever main body 9B about a rotation axis 9C and has a claw 9D at one end and a recess 9E at the other end, and a sub-bracket 9F.
A bar 9G that engages with the concave portion 9E of F and a grip portion 9H
It is composed of.

Next, to explain the action of the accelerator lever 9,
The position of the accelerator lever 9 indicated by the solid line is engine 2.
indicates a state in which it is at the rated rotation, and from this state, push the bar 9G of the accelerator lever 9 to release the engagement between the pawl 9D and the sawtooth profile 10A, and then manually rotate the accelerator lever 9 in the direction of the arrow X. Then, the accelerator lever 9 is in the state shown by the two-dot chain line (engine idling position). As the accelerator lever 9 rotates, the second rod 13, wire 12, and first rod 11 move in the direction of arrow Y, and the engine 2 becomes idling.

In this way, by operating the accelerator lever 9, the engine 2 can be switched to the rated rotation state or the idling state.

Figure 5 shows the foot brake device 1 along with Figure 4.
6 is shown.

This foot brake device 16 is provided separately from the above-mentioned running hydraulic circuit of the snowplow, and includes a hydraulic brake device 17 and a pedal section 18 (details are shown in FIG. 4).
It is composed of. Hydraulic brake device 17
is the master cylinder 19 and the brake pipe 20
, brake cylinder part 21, and brake disc 2
It consists of 1a. The pedal section 18 is a fourth
As shown in the figure, rod 1 of master cylinder 19
A brake pedal 22 that expands and contracts the brake pedal 9A via a sub-bracket 22A, a pedal spring 23 that constantly tensions the brake pedal 22, and a bracket 24 that supports one end of the pedal spring 23.
It is composed of. The brake pedal 22 shown by a solid line shows a state in which it is not depressed, and when the brake pedal 22 in this state is depressed, the brake pedal 22 rotates about the rotation axis 22B,
The state shown by the two-dot chain line is reached, and the rod 19A of the master cylinder 19 is pushed. As a result, the oil in the master cylinder 19 is pressurized and acts on the brake cylinder section 21 via the brake pipe 20, and this brake cylinder section 21 causes the brake disc 2
The brake is applied to 1a, and the hydraulic motors 4A, 4
The structure is such that the rotation of sprockets 5A and 5B connected to drive shafts S _A and S _B is stopped.

[Problem that the invention attempts to solve]

When the above-mentioned snowplow travels, such as when making a turn, the engine is operated at a rated speed, and the hydraulic pump 1 is controlled by the pump operating lever 7, thereby controlling the running speed of the snowplow. and,
When applying the brakes to this running snowplow, it is necessary to return the pump operating lever 7 to the neutral position, apply the braking effect in the hydraulic circuit, and then step on the brake pedal 22. However, in an emergency, if only the brake pedal 22 is operated without returning the pump operating lever 7 to the neutral position, the hydraulic motors 4A and 4B are in the rated rotation state, and the hydraulic driving force is still being applied to the snowplow.
You will have to apply the foot brake. Therefore, this hydraulic drive force reduces the foot brake force,
Snowplows cannot stop suddenly, and safety cannot be ensured in the event of an emergency.

[Purpose of invention]

The present invention was developed to solve the above-mentioned problem, and its purpose is that when applying the brakes while the work vehicle is running, even if the brake pedal is depressed without returning the pump operating lever to the neutral position, the foot To provide a brake device for a hydrostatically driven traveling work vehicle in which the braking force does not decrease.

[Means for solving problems]

In order to achieve the above object, the present invention supplies oil from a hydraulic pump operated by an engine to a hydraulic motor by operating the pump operating lever, and rotates a drive shaft by operating the hydraulic motor. a hydrostatic drive device for driving the vehicle; an engine rotation switching device for switching the engine to a rated rotation state or an idling state by operating an accelerator lever; and an engine rotation switching device for switching the engine to a rated rotation state or an idling state by operating an accelerator lever; In the brake system of a hydrostatically driven traveling work vehicle, the brake system is equipped with a brake system that applies a brake to the drive shaft to stop the vehicle, and the brake system of the hydrostatically driven traveling work vehicle is configured to change the position of the accelerator lever to the engine's rated rotation in conjunction with depression of the brake pedal. An interlocking device for switching from the engine position to the engine idling position is provided in the engine rotation switching device and the brake device.

[Effect of invention]

According to the present invention, if the brake pedal is depressed without returning the pump operating lever to the neutral position, the interlocking device provided in the engine rotation switching device and the brake device automatically changes the accelerator lever position from the engine rated rotation position. The engine is switched to the idling position, and the engine changes from the rated rotation state to the idling state. Therefore, the brake is activated after the amount of oil supplied from the hydraulic pump to the hydraulic motor is almost exhausted and the hydraulic driving force is no longer available, and the vehicle is stopped safely and reliably.

[Example of idea]

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

FIG. 1 shows an embodiment in which the present invention is applied to a snowplow, in which the conventional device shown in FIG. 4 is provided with the following interlocking device. In this embodiment, the same parts as those of the conventional device are given the same reference numerals, and the explanation thereof will be omitted.

In FIG. 1, 25 is an interlocking device provided on the engine rotation switching device 8 and the pedal section 18, which changes the position of the accelerator lever 9 from the engine rated rotation position to the engine idling position in conjunction with the depression of the brake pedal 22. The position is changed. To explain in detail, the interlocking device 25 includes a pusher 22C provided near the rotating shaft 22B of the brake pedal 22, a limit switch 26 that detects the depressed position of the brake pedal 22 by the pusher 22C, and a
a solenoid 27 whose solenoid rod 27A expands and contracts in response to an ON-OFF signal from a wiring 26A;
A rotary lever 29 is connected to the solenoid rod 27A and rotatably supported by a support shaft 29a on a bracket 28 provided on the cab floor F of the driver's cab H of the vehicle; The third rod 30 has one end that presses the pawl 9D of the sub-bracket 9F, and one end that presses the pawl 9D of the sub-bracket 9F.
and a lever spring 31 that is supported by and constantly pulls the rotating lever 29.

Next, to explain the operation of this embodiment, the solid line in FIG. 1 shows the time when the brake pedal 22 is not depressed.
It is in the OFF state. brake pedal 22
When you press , the state shown by the two-dot chain line will appear, and Pushiya 2 will appear.
2C leaves the limit switch 26. When the pusher 22C is released, the brake pedal 22
is detected, and the limit switch 26 is activated.
is in the ON state.

When the limit switch 26 is turned on,
This signal reaches the solenoid 27 through the wiring 26A, and the solenoid rod 27A contracts. Therefore, the rotating lever 29 rotates counterclockwise about the support shaft 29a, and becomes in the state shown by the two-dot chain line. Along with this, the third rod 30 moves in the direction of arrow Z,
Its tip presses the claw 9D of the accelerator lever 9. As a result, the engagement between the pawl 9D and the saw tooth 10A is released, and the accelerator lever 9, which is at the engine rated rotation position shown by the solid line, is rotated in the X direction by the tensile force of the tension spring material 14, and The engine will switch to the engine idling position shown in . Therefore, the engine 2 switches from the rated rotation state to the idling state.

In short, when the brake pedal 22 is depressed, the position of the accelerator lever 9 is automatically switched from the engine rated rotation position to the engine idling position by the engine rotation switching device 8 and the interlocking device 25 provided in the brake device, and the engine 2 is It changes from rated rotation state to idling state. Therefore, even if the pump operating lever 7 shown in FIG. 3 is not in the neutral position and is in the forward or reverse position, the hydraulic pump 1
The amount of oil supplied to the hydraulic motors 4A and 4B is almost gone.

As a result, the rotational force of the hydraulic motors 4A, 4B is almost eliminated, and the foot brake can be applied to the snowplow with almost no hydraulic driving force. Therefore, the foot brake force is not reduced by the hydraulic drive force, and the snowplow can be stopped suddenly, and safety can be ensured even in an emergency.

Although the present embodiment has been described using a snowplow as an example, the present invention is not limited thereto, and can also be applied to hydrostatically driven working vehicles such as crane trucks and backhoes.

Further, in this embodiment, the description has been given by taking a snow plow that runs on crawlers as an example, but the present invention is not limited to this, and can also be applied to a hydrostatically driven traveling work vehicle that runs on wheels. can.

Further, in this embodiment, the engine rotation switching device 8 has a structure controlled by the tensile force of the wire, but is not limited to this, and may have a structure controlled by other hydraulic or pneumatic pressures, for example. You can also.

In this embodiment, the interlocking device 25 is
Although the structure is mechanical, the structure is not limited to this, and for example, a structure using other hydraulic and pneumatic systems may also be used.

[Effect of idea]

As described above, according to the present invention, in the brake system of a hydrostatically driven traveling work vehicle, when applying the brakes while driving, even if the brake pedal is depressed without returning the pump operating lever to the neutral position. , it is possible to prevent the foot braking force from decreasing, and in turn, it is possible to bring the snow plow to a sudden stop without reducing the foot braking force, thereby ensuring safety even in an emergency. play.

[Brief explanation of drawings]

Fig. 1 is a diagram showing the main parts of a brake device for a hydrostatic working vehicle according to an embodiment of the present invention, Fig. 2 is a side view of a snowplow, Fig. 3 is an explanatory diagram of the driving principle of the snowplow, and Fig. 4 is a diagram illustrating the driving principle of the snowplow. The figure shows a conventional engine rotation switching device and a foot brake device, and FIG. 5 shows a foot brake system diagram of the present embodiment and a conventional snowplow. 1... Hydraulic pump, 2... Engine, 4A, 4
B... Hydraulic motor, 5A, 5B... Sprocket, 6... Crawler, 7... Pump operating lever,
8... Engine rotation switching device, 9... Accelerator lever, 16... Foot brake device, 17... Hydraulic brake device, 18... Pedal section, 19... Master cylinder, 20... Brake pipe, 21...
...Brake cylinder section, 25...Interlocking device.

Claims (1)

[Scope of utility model registration request] A hydrostatic drive system that supplies oil from a hydraulic pump operated by an engine to a hydraulic motor by operating its pump operating lever, and that operates the hydraulic motor to rotate a drive shaft to drive the vehicle, and an accelerator lever. an engine rotation switching device that switches the engine to a rated rotation state or an idling state by operating the engine, and a braking mechanism that operates by stepping on a brake pedal to brake the drive shaft rotated by the hydraulic motor to stop the vehicle. In a brake device for a hydrostatically driven traveling work vehicle, the interlocking device switches the position of the accelerator lever from the engine rated rotation position to the engine idling position in conjunction with depression of the brake pedal. A brake device for a hydrostatically driven traveling work vehicle, characterized in that it is provided in a rotation switching device and a brake device.