JPS61266802A - Locking circuit for vehicle-mounted hydraulic device - Google Patents

Abstract

PURPOSE:To prevent malfunction of hydraulically driven equipments due to oil pressure loss by transmitting vibrations caused by a vehicle being driven to a hydraulic pressure generator comprising a small plunger pump and by supplying the generated pressure oil into a hydraulic circuit. CONSTITUTION:A hydraulic pressure generator f is connected to a line 14 supplying pressure oil discharged from a pump p to a hydraulically driven device a. The hydraulic pressure generator f comprises a hydraulic cylinder 7 of a small plunger pump receiving vibrations of a vehicle being driven, a suction check valve 9, and a discharge check valve 10, all interposed between the line 14 and a tank 13 so as to supply pressure oil to a hydraulic circuit utilizing the vibrations of the running vehicle. Thus, hydraulic pressure loss is prevented so that the hydraulically driven device a can be operated accurately.

Description

Detailed Description of the Invention (Related Industrial Field) The present invention relates to a so-called locking circuit that stops the movement of objects in hydraulic systems used in specially equipped vehicles such as cargo handling and labor-saving vehicles, construction work vehicles, and facility service vehicles. It is something. More specifically, in order to stop the moving parts of the onboard equipment from moving while the specially equipped vehicle is running, the on-vehicle equipment can be maintained in a stopped state by stopping the hydraulic system that drives the moving parts. The present invention relates to a locking circuit for a hydraulic system.

(Prior Art) As a means for stopping the movement of the movable parts of the equipment mounted on the above-mentioned specially equipped vehicle, a locking circuit is provided in the hydraulic system a that drives the movable parts of the equipment as shown in FIG. This structure is common. This locking circuit is
As shown in FIG. 7, check valves B, electromagnetic switching valves C, etc. had to be installed in ascending order in the hydraulic circuit. These ascending orders promise that oil will not flow on the circuit diagram, but in reality, a small amount of oil leakage is unavoidable. For this reason, it is nearly impossible to completely stop the equipment installed in the specially equipped vehicle without driving the pump P of the hydraulic system.

As a solution to this problem, there is a method of detecting a pressure drop in the hydraulic circuit and driving the pump P to pressurize it to maintain the oil pressure, but this also included the risk of burning out the pump motor depending on the reliability of the pressure switch. .

(Problems to be Solved) The present invention was invented in view of the above-mentioned prior art.
Vibration energy (vertical vibration,
A locking circuit of a pressure oil generating device that utilizes acceleration/deceleration, etc.) was connected to the hydraulic circuit, so that pressure oil could be automatically replenished, and the pressure in the hydraulic circuit was always maintained at a predetermined pressure.

(Means for solving the problem) A hydraulic system that drives equipment mounted on the vehicle, and a device that is fixed to an appropriate location on the vehicle and absorbs the vibration energy of the vehicle drive a piston to generate pressure oil. an oil generator, the suction pipe of the pressure oil generator is connected to the oil tank of the hydraulic device via a check valve, and the discharge pipe of the pressure oil generator is connected to the pipe line of the hydraulic device via the check valve. Even if pressure reduction occurs within the hydraulic system, the hydraulic pressure can always be maintained by this pressure oil generator.

(First Embodiment) A labor-saving cargo handling vehicle (hereinafter referred to as a lifter vehicle) equipped with a tailgate lifter for raising and lowering cargo on the rear surface of the pan-type vehicle will be described below. As shown in Figure 8, the tailgate lifter T uses a hydraulic cylinder A to lift and lower the movement between the ground and the loading platform ((■) in Figure 8), and lifts between the loading platform and the vertical storage position ((■) in Figure 8).
The turning movements shown in the figure (■)) are configured to be operated by hydraulic cylinders B, respectively.

When the lifter vehicle travels on the road, the arm d of the tailgate lifter T is raised and the gate plate e is vertically retracted, as shown by the solid line in FIG. This holding means maintains the oil pressure of cylinder A, which is activated when arm d is raised, and the oil pressure of cylinder B, which is activated when gate plate e is rotated, by holding them as they are without driving the pump. However, it is impossible to maintain the cylinder oil pressure for a long time.

Therefore, the present invention is designed to reduce the vibrations that a vehicle receives while driving.

Transmitted to a small plunger pump type pressure oil generator,
The idea is to replenish this hydraulic pressure by connecting it in parallel to a hydraulic circuit that has been depressurized due to an oil leak.

This hydraulic system will be explained below with reference to FIG.

In FIG. 2, 1 is a weight whose arm 2 is pivotally connected to a link 3. The link 3 is pivotally mounted on the valve body 5 via a bearing 4. A hydraulic cylinder 7 is installed in the center of the arm 2.
The upper end of a piston 6 that moves up and down inside is pivotally mounted. 8
is oil.

9.10 is a check valve provided in the pipe 12, and these check valves 9. During IO, the oil 8 in the hydraulic cylinder 7 communicates via the line 11.

One end of the pipe 12 is connected to a tank 13 common to the pump P via a flexible pipe 15, and the other end is connected to a pipe 14 connecting the pump P and the hydraulic device a.

Although this pressure oil generating device f can be installed at an appropriate location on the vehicle, it is particularly effective to install it on the vehicle body above the suspension system (FIG. 3).

(Operation of the first embodiment) When the vehicle vibrates, the weight 1 vibrates up and down, and this vibration is transmitted to the piston 6 and generates pressure oil in the hydraulic cylinder 7. This pressure oil is sent to the piping 14 in FIG. 1 through the check valve 10, and supplies pressure oil to the hydraulic system a.

(Second Embodiment) While the vehicle is running, the area where the amplitude of vibration generated in the vehicle is large is the upper portion of the spring of the suspension system (FIG. 3, 16). By attaching the pressure oil generator f' (FIG. 4) to this location, the structure of the pressure oil generator can be further simplified. In this case, a weight 1' is attached to a piston 6' that moves up and down within a hydraulic cylinder 7' of a pressure oil generator [f'. 17 is a spring.

It urges the piston 6' upward. Oil is stored in the portion where the spring 17 is housed.

In the case of this second embodiment as well, a check valve 9 is provided in the valve body 5.
, 10 are provided, and a cylinder and a pipe 11 are provided in the middle thereof.
It is understood.

(Operation of the second embodiment) When the vehicle vibrates, the piston 6' integrated with the weight 1' vibrates against the spring 17 and generates pressure oil, which passes through the check valve 10 and enters the pipe. 14 to the hydraulic cylinder 7' to replenish pressure oil.

(Third Embodiment) FIG. 5 shows a modification of the second embodiment, in which a pressure oil generator f' is fixed to the frame 19, and the vibration of the axle 18 is directly transmitted to the piston 6".
It is now possible to call. In this case, an extremely large amount of pressure oil is generated depending on the vibration amplitude, so a pressure reducing valve circuit as shown by g in FIG. 1 is provided to prevent the generation of excessive pressure.

(Operation of the third embodiment) When the axle 18 vibrates, the piston 6' is moved by the spring 17.
′ vibrates against the pressure and generates pressure oil. Then, this pressure oil passes through the check valve 10 and the piping 14 to the hydraulic cylinder 7'.
is supplied to supply pressure oil.

The oil pressure in the pipe 14 is controlled by a pressure reducing valve g.

(Effects of the Invention) According to the present invention, the piston of the pressure oil generating device is actuated using vibrations generated while the vehicle is running to generate pressure oil in the hydraulic cylinder, and this pressure oil is transferred to the vehicle. Even if the hydraulic system loses pressure while the vehicle is running, it is possible to constantly replenish the circuit with pressurized oil.

The operation of the hydraulic drive equipment mounted on the vehicle is ensured, and the reliability of the traveling vehicle can be improved.

In addition, the structure is simple and can be manufactured at low cost, making it possible to use existing machines □
It has excellent effects such as being able to be easily attached to a container.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a first embodiment of a locking circuit for a hydraulic system according to the present invention. FIG. 2 is a detailed sectional view of the pressure oil generator. FIG. 3 is a diagram showing an example of the mounting position of the pressure oil generator. FIG. 4 is a sectional view of a second embodiment of a pressure oil generating device for a locking circuit according to the present invention. FIG. 5 is a sectional view of a third embodiment of the pressure oil generator. FIG. 6 shows the mounting position of the pressure oil generator of the third embodiment. Figure 7 is a locking circuit diagram of a conventional hydraulic system. FIG. 8 is a side view of the rear part of the car with the lid to which the present invention is applied. In the figure: P Pump T Tailgate lifter a Hydraulic system b Check valve C switching valve d Arm e Gate plate f, f', f' Pressure oil generator g Pressure reducing valve A, B Hydraulic cylinder 1.1' Weight 2 Arm 3 Link 4 Bearing 5 Valve body 6.6', 6' Piston 7
．． 7' Hydraulic cylinder 8 ゛ Oil (in the cylinder) 9.10 Check valve 11 Piping 12 Piping 13 Tank I4 Piping
15 Flexible tube 16 Vehicle suspension system 17, 17'
Spring 18 Axle 19 Frame or more

Claims (1)

[Claims] [I] A hydraulic system that drives equipment mounted on a vehicle and a device that is fixed to an appropriate location on the vehicle and absorbs vibration energy of the vehicle drive a piston to generate pressure oil. The suction pipe of the pressure oil generator is connected to the oil tank of the hydraulic device via a check valve, and the discharge pipe of the pressure oil generator is connected to the pipe line of the hydraulic device via the check valve. A locking circuit for an on-vehicle hydraulic system, characterized in that: [II] The locking of the vehicle hydraulic system according to claim [I], characterized in that a swingable heavy flange arm is pivotally attached to the tip of the piston rod to receive vibration energy of the vehicle. circuit. [III] The locking circuit for a vehicle-mounted hydraulic system according to claim [I], characterized in that a weight is attached to the piston to receive vibration energy of the vehicle. [IV] Claims characterized in that energy due to displacement of the frame and suspension system is accepted [
Locking circuit for the on-vehicle hydraulic system described in [I].