JPS63253B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention cuts off the supply of pressure fluid to the fluid pressure motor in conjunction with a braking operation for a traveling device driven by the fluid pressure motor, and connects the fluid supply port of the fluid pressure motor with The fluid pressure motor is forcibly driven as a pump by the inertia of the vehicle body during braking, and the fluid pressure motor also provides braking force. The present invention relates to a driving system operation structure for a working vehicle.

As an example of the traveling system operating device for the work vehicle mentioned above, as described in Japanese Patent Publication No. 52-21655, a variable displacement fluid pressure pump and a fluid pressure motor are connected to form a closed circuit and the vehicle is driven. In conjunction with the braking operation on the device, the swash plate angle of the variable displacement fluid pressure pump is operated to neutral to stop the supply of pressure fluid to the fluid pressure motor, and the fluid supply port and fluid discharge port of the fluid pressure motor are closed. Some devices are configured to be connected via a throttle channel, but since the discharge of pressure fluid from the fluid pressure pump is stopped in conjunction with the braking operation, this fluid pressure pump is used to connect the drive motor. If the construction is configured to also drive a work drive device other than the work drive device, the pressure fluid supply to the work drive device will be cut off each time a braking operation is performed, and the drive of the work device will stop.To avoid such a situation, Therefore, it was necessary to provide a separate fluid pressure pump for the working equipment.

The present invention has been made in view of the above-mentioned circumstances, and by devising a fluid pressure circuit, the pressure fluid from the fluid pressure pump that drives the fluid pressure motor for traveling can be controlled with or without braking operation. It is an object of the present invention to enable effective use of a fluid pressure pump by supplying it to a working drive device regardless of the situation.

The characteristic structure of the driving system operating structure of a work vehicle according to the present invention to achieve the above object is that an on-off valve is provided between a pump flow path that supplies pressure fluid from a fluid pressure pump and a tank flow path that communicates with the tank side. a linkage mechanism connected to a hydraulic motor for traveling through a fluid pressure motor for driving, and connecting the on-off valve and a braking device for the traveling device so as to reversibly switch the on-off valve to a closed state in conjunction with a braking operation on the braking device; a flow path that communicates and connects the pump flow path and the tank flow path to the closed port of the on-off valve; and a fluid supply flow path and a fluid discharge flow path on the fluid pressure motor side. A flow path is formed which communicates and connects the two through the throttle, and this configuration provides the following effects.

In other words, when the on-off valve is switched to the closed state in conjunction with the braking operation for the traveling device, the supply of pressure fluid to the fluid pressure motor is cut off, and the fluid supply port and fluid discharge port of the fluid pressure motor are connected to the constricted flow path. Braking force is also applied by the fluid pressure motor, but since the fluid pressure pump itself continues to operate, pressure fluid is not supplied from this fluid pressure pump to the work drive device. Even if the fluid pressure pump is configured to supply hydraulic fluid, there is no problem that the drive of the working device is stopped every time a braking operation is performed, and the fluid pressure pump for the traveling device can also be effectively used for driving the working device. effective.

Moreover, since the discharge of pressure fluid from the fluid pressure pump is not stopped each time a braking operation is performed, when the braking operation is released, the vehicle starts in the running mode before braking, and the vehicle frequently stops and starts. Another advantage is that it is easy to operate when repeating.

Next, embodiments of the present invention will be described in detail with reference to the drawings.

A swivel base 3 is attached to a vehicle body 2 equipped with a tire-type traveling device 1.
, an excavation work device A consisting of a boom 4, an arm 5, a bucket 6, a cylinder 7, etc. is installed on the swivel base 3, and an engine 8 and a control section 9 are mounted on the swivel base 3 to constitute an excavation work vehicle. There is.

The driving and braking devices B and C for the traveling device 1 are constructed by two fluid pressure motors M1 mounted on the input shaft 11 of a transmission case 10 incorporating a mechanical sub-transmission device, as shown in _FIG . _{. _ _ _ _} A valve V ₁ is provided on the traveling vehicle body side, which connects the motors M ₁ and M ₂ by a flow path, and switches the motors M ₁ and M ₂ between a state where they are connected in parallel and a state where they are connected in series. Both motors M ₁ , M ₂
switching of the supply state of pressure fluid to the auxiliary transmission, four-speed gear shifting operation by the sub-transmission device, and control valves V,
The transmission shaft 14 is connected to the speed change output shaft 13 so that forward and backward switching operations including stopping can be performed by V.
Attach the tires 1a... through the travel drive device B.
, and each of the tires 1a is provided with a hydraulic inward expansion type braking mechanism 15, and each of the braking hydraulic cylinders 15a and a master cylinder 17 connected to the pedal 16 on the swivel base side, They are connected by a flow path passing through the rotary joint 12 to form a hydraulically operated braking device C.

In the drive device B, a pump flow path (21 or 22) for supplying pressure fluid from the fluid pressure pumps P ₁ and P ₂ is provided in the flow path between the travel control valves V, V and the rotary joint 12. Fluid supply channel (23 _{or 2}
4) and an open port in a flow path open state that connects the tank flow path (22 or 21) communicating with the tank T to the fluid discharge flow path (24 or 23) from the motors M ₁ and M ₂ a, and the pump flow path (2
1 or 22) and the tank flow path (22 or 21), and the fluid supply flow path (23 or 24) for the motors _M1 , _M2 and the motors _M1 , M2 _.
Throttle the fluid discharge channel (24 or 23) from 2
The on-off valve V ₂ is provided with a closed port b in a flow path closed state connected by a flow path provided with a flow path 5, and this on-off valve V ₂ is of a spring return type fluid pressure operated type, and the braking device A flow path 18 is provided to supply a fluid for braking operation of C as a pilot fluid to the on-off valve V ₂ , so that the braking operation on the braking device C is quickly performed and the on-off valve V ₂ is automatically and reversibly activated. It is designed to switch to the closed port b in the closed state, and only by braking the brake device C, the supply of pressure fluid to the drive device B is stopped, and the pressure fluid is returned to the tank flow path to increase the pressure. This eliminates fluid relief and circulates pressurized fluid to the motors M ₁ and M ₂ in a constricted state to ensure smooth braking.

In order to turn off the on-off valve _V2 in conjunction with the operation of the braking device C, the pilot flow path was used as the linking mechanism 18 to link the braking device C and the on-off valve _V2 . Valve V ₂ may also be coupled mechanically or electrically.

Incidentally, although reference numerals are written in the claims section for convenient comparison with the drawings, the present invention is not limited to the structure shown in the accompanying drawings.

[Brief explanation of the drawing]

The drawings show an embodiment of the driving system operating structure for a working vehicle according to the present invention, and FIG. 1 is an overall side view of the working vehicle, and FIG. 2 is a system diagram of the driving system operating structure. 18... Linkage mechanism, 21, 22, 23, 24...
...flow path, 25...throttle, T...tank, M ₁ , M ₂
...Fluid pressure motor for traveling device, a, b...port, V...control valve for traveling, C...braking device, V ₂
...Open/close valve.

Claims (1)

[Claims] 1. An opening/closing valve between a pump flow path (21 or 22) that supplies pressure fluid from the fluid pressure pumps P ₁ and P ₂ and a tank flow path (22 or 21) that communicates with the tank T side. The on-off valve V ₂ is connected to the hydraulic motors M ₁ and M ₂ for traveling via V 2 , and the on-off valve V ₂ and a braking device C for the traveling device 1 are connected to _The pump flow path (21 or 22) and the _tank flow path ( 22 or 21), and the fluid supply channel (23 or 24) and fluid discharge channel (24 or 23) on the fluid pressure motor M ₁ , M ₂ side via the throttle 25. A driving system operating structure for a work vehicle, which has a flow path that communicates with it. 2. A traveling system operating structure for a working vehicle according to claim 1, wherein the linkage mechanism 18 is mechanically configured. 3. A traveling system operating structure for a work vehicle according to claim 1, wherein the linkage mechanism 18 is electrically configured. 4. The braking device C is of a fluid pressure operated type, and the linking mechanism 18 is connected to the on-off valve V ₂ for the braking operation fluid.
2. A traveling system operating structure for a working vehicle according to claim 1, wherein the operating structure is constructed of a flow path for supplying pilot fluid as a pilot fluid.