JPS6021588Y2 - Hydraulic motor reduction device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for reducing or decelerating the rotational speed of a hydraulic motor.

Conventionally, in this kind of apparatus, for example, as shown in FIG.
It is known that deceleration is effected by a deceleration relief valve d provided in It is also known that the control cylinder h is operated by the pressure of the pilot circuit g introduced at Until then, the deceleration is relatively good, but after the valve is opened, the deceleration pressure in the outlet side circuit i decreases due to the general characteristics of the relief valve, and the deceleration time of the hydraulic motor a in the low rotation range becomes long. It is a victory even though it causes some inconvenience.

The object of the present invention is to provide a hydraulic motor speed reduction device that does not have such inconveniences. Relief valve 4 for deceleration installed in
The regulator 5, which can freely decelerate and further control the discharge amount of the dual discharge variable displacement pump 2, is connected to a spool-type pilot control valve 6 which is operated by the action of pilot pressure from the pressure circuit 20 in one direction. 6, the pilot control cylinder 8 is actuated by the pressure of a pilot circuit 7 introduced through the pilot circuit 6, and the pilot control cylinder 8 is operated by the pressure of the pilot circuit 7 introduced through the motor 1. The pressure circuit 20 is provided with a switching valve 9 for applying pilot pressure to the valve 6 in a direction opposite to the one direction.

FIG. 2 shows one example of this, in which the hydraulic circuit 3 is configured as a closed circuit, and a fixed displacement pump 11 is provided which is rotated by a prime mover 10 together with both variable discharge displacement pumps 2. The hydraulic circuit 3 is replenished with fluid via a replenishment circuit 12.

The pilot circuit 7 is further connected to the replenishment circuit 12 via a second pilot control valve 13, and the control cylinder 8 of the regulator 5 is operated by the oil pressure of the replenishment circuit 12 to increase the discharge amount of the pump 2. When the pressure in the hydraulic circuit 3 increases, the pressure acts on the second pilot control valve 12 via the shuttle valve 14, and the pilot circuit 7 is connected to the tank 15, and the regulator 5 adjusts the discharge amount of the pump 2. It operates to reduce the

The replenishment circuit 12 is connected to a tank 15 or relief valves 18 and 19 via a throttle valve 16 and a solenoid valve 17.
A pressure control circuit 20 connected to the regulator 5 is provided so that the pilot control valve 6 of the regulator 5 can be operated at various pressures.

The above configuration is almost the same as that of the conventional one, but in the one of the present invention, a switching valve 9 is interposed between the throttle valve 16 and the solenoid valve 17 of the pressure control circuit 20, and the switching operation of the switching valve The pilot control valve 6 of the regulator 5 was activated, and the control cylinder 8 was driven in the opposite direction, causing both variable discharge displacement pumps 2 to perform reverse discharge.

To explain this further, a pressure circuit 22 equipped with a relief valve 21 is added to the switching valve 9, one end of which is connected to the pilot control valve 6 so as to face the pressure from the pressure control circuit 20, and the switching valve By operating step 9, the pilot control valve 6, which had been in the neutral position or the switching position displayed to the left thereof, is switched to the switching position displayed to the right, and the control cylinder 8 is moved to the opposite side. Thus, the discharge direction of the double discharge variable displacement pump 2 to the hydraulic circuit 3 is reversed, and hydraulic pressure is discharged to the circuit 3a on the discharge side of the hydraulic motor 1.

This reverse discharge of the pump 2 prevents the pressure in the circuit 3a from decreasing due to the opening of the deceleration relief valve 4 provided therein.
The deceleration performance of the hydraulic motor 1 in the low rotation range is improved.

In addition, in this case, the discharge amount of the pump 2 to the motor deceleration side is the second
The pilot control valve 13 controls the required minimum amount.

In this way, according to the present invention, the double discharge variable displacement pump 2
Pressure oil is introduced into the pilot control valve 6 that constitutes the regulator 5 of the hydraulic circuit 3 via the switching valve 9 that is operated when the hydraulic motor 1 is decelerated, and the pump 2 is caused to perform reverse discharge. Even after the deceleration relief valve 4 is opened, the hydraulic motor 1 can be decelerated favorably, and the conventional disadvantages in the low rotation range of the motor 1 can be eliminated.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional example, and FIG. 2 is a diagram showing an example of the device of the present invention. 1...Hydraulic motor, 2...Double discharge variable displacement pump, 3...Hydraulic circuit, 4...
Relief valve for deceleration, 5...Regulator, 6.
...Pilot control valve, 7...Pilot circuit, 8...Control cylinder, 9...
switching valve.

Claims (1)

[Scope of utility model registration request] A hydraulic motor 1 is driven by a hydraulic circuit 3 having a double discharge variable displacement pump 2, and the motor 1 can be decelerated by a deceleration relief valve 4 provided in the circuit 3, and further the discharge of the double discharge variable displacement pump 2 is controlled. The regulator 5 that controls the amount is operated by a spool-shaped pilot control valve 6 that is operated by the unidirectional action of pilot pressure from the pressure circuit 20 and the pressure of the pilot circuit 7 that is introduced through the control valve 6. In the control cylinder 8, a pilot pressure is applied to the pilot control valve 6 in a direction opposite to the one direction in order to cause the pump 2 to reverse discharge when the motor 1 decelerates. The switching valve 9 is connected to the pressure circuit 20.
Hydraulic motor reduction device that should be installed.