JPS6224082Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a hydraulic control device that performs high-speed operation when the load is small and low-speed operation when the load is large.

Conventionally, this type of hydraulic control device has been used, for example, as shown in Utility Model Publication No. 49-10717, or as shown in Japanese Patent Publication No. 39-15087. It is considered. However, none of these methods takes into account the need to perform speed control using flow control valves separately during small loads and large loads. In the former case, in order to separately control the speed with a flow control valve, the unloading pressure of the unloading valve must be increased so that the unloading valve does not unload when the load is small.
When the operating pressure becomes slightly lower during heavy loads, the unload valve operates to unload, causing a problem in which flow rate control accuracy deteriorates. In the latter case, in order to control the speed separately with a flow control valve, during low-speed operation under heavy loads, it is necessary to control the speed by throttling the supply oil that supplies pressure oil with the flow control valve. A problem occurs in which accurate speed control cannot be performed. Moreover, small cylinders must be disposed on both sides of the large cylinder, which cannot be manufactured at low cost. Furthermore, in general, low-speed operation under heavy loads such as machining feed of machine tools is
The speed is controlled by constricting the minute amount of discharged oil, such as cm ² /min or less, using a flow control valve, but there is a problem that the flow rate control accuracy deteriorates as the control flow rate becomes minute.

The present invention provides a hydraulic control device that can perform good speed control using flow control valves separately during small loads and large loads, and can perform low-speed operation during large loads with good flow control accuracy. be.

Therefore, in the present invention, a large cylinder body with a large diameter sliding hole and a small cylinder body with a small diameter sliding hole are coaxially arranged, and a large diameter piston can freely slide into the large diameter sliding hole. A small-diameter piston is slidably fitted into a small-diameter sliding hole to partition a small-diameter forward-motion chamber and a small-diameter return-motion chamber. A piston rod is provided which connects the large diameter piston and the small diameter piston so as to operate integrally, and protrudes outward from at least either the large cylinder body or the small cylinder body, and supplies pressurized oil to the small diameter forward movement chamber. One switching valve discharges discharged oil from the small-diameter double-acting chamber, and one flow control valve controls the throttling of the discharged oil from the small-diameter double-acting chamber to achieve high-speed operation during small loads.
The other side connects the large-diameter forward movement chamber and the large-diameter reciprocating chamber without supplying pressure oil when the load is small, and supplies pressure oil to the large-diameter forward movement chamber and discharges discharged oil from the large-diameter return movement chamber when the load is large. One switching valve is provided, and the other flow control valve controls the exhaust oil from the large-diameter reciprocating chamber that is discharged from the other switching valve during heavy loads to achieve low-speed operation.
The oil discharged from the small-diameter double-acting chamber is throttled and constricted by one flow control valve, and during heavy loads, the discharged oil from the large-diameter double-acting chamber is throttled and constricted by the other flow control valve to ensure accurate high-speed operation. It is designed to operate at low speed.

An embodiment of the present invention will be described below based on the drawings.

Reference numeral 1 denotes a large cylinder, and a large cylinder main body 5 is constructed by screwing an end cover 3 and an intermediate cover 4 to the cylindrical body 2 so as to close the openings at both ends of the cylindrical body 2. 6
is a small cylinder, and an end cover 8 and an intermediate cover 4 are screwed to the cylindrical body 7 so as to close openings at both ends of the cylindrical body 7 to form a small cylinder main body 9. The large cylinder main body 5 and the small cylinder main body 9 share the intermediate lid 4 and are coaxially connected. The large-diameter piston 11 is slidably fitted into the large-diameter sliding hole 10 of the large cylinder body 5, and the large-diameter forward movement chamber 12A and the large-diameter return movement chamber 12B are formed.
are divided into sections. A small-diameter piston 14 is slidably fitted into a small-diameter sliding hole 13 of a small cylinder main body 9 to define a small-diameter forward movement chamber 15A and a small-diameter return movement chamber 15B. Large diameter piston 1 for integrated operation
A piston rod 16 connecting the piston 1 and the small diameter piston 14 is slidably inserted through the end cover 3 and the intermediate cover 4. 17 and 18 are seal rings, and 19 is a hydraulic power source. 20 is a directional switching valve having switching positions X, Y, and Z, the P port is connected to the hydraulic pressure source 19, the R port is connected to the low pressure oil tank 21, and the A port is connected to the small diameter reciprocating chamber 15B.
and the B port are respectively connected to the small diameter forward movement chamber 15A. 22 is a flow control valve, 23 is a check valve,
24 is a pressure switch. 25 is switching position CD
The P port is a directional control valve with a hydraulic power source 19.
, the R port is connected to the low pressure oil tank 21, the A port is connected to the large diameter reciprocating chamber 12B, and the B port is connected to the large diameter reciprocating chamber 12A.
are connected to each other. 26 is a flow control valve.

The operation in the above configuration will be explained. From the illustrated state, when the directional control valve 20 is switched to the switching position be done. The piston rod 16 is moved forward by pressure oil acting on the small diameter piston 14,
The oil discharged from the large diameter reciprocating chamber 12B is the large diameter forward moving chamber 12B.
A, the piston rod 16 performs high-speed forward movement under small loads. Small diameter forward movement chamber 15 due to large load
When the pressure of A rises and the pressure switch 24 is activated, the directional control valve 25 is switched to the switching position C, and pressure oil is also supplied to the large diameter forward motion chamber 12A, and the large diameter backward motion chamber 12B is
The discharged oil is condensed by the flow control valve 26 and sent to the oil tank 2.
1. The piston rod 16 is moved forward by pressure oil acting on the small-diameter piston 14 and the large-diameter piston 11, and the piston rod 16 performs low-speed operation under heavy loads. For low-speed operation under heavy loads, a large amount of oil discharged from the large-diameter reciprocating chamber 12B is transferred to the flow control valve 26.
Since the speed is controlled by constricting the flow rate, it is possible to control the flow rate with good accuracy. Next, when the directional switching valve 20 is switched to the switching position Z and the directional switching valve 25 is switched to the switching position D, the pressure oil flows through the check valve 23 to the small diameter reciprocating chamber 15.
The oil discharged from the small diameter forward motion chamber 15A is discharged to the oil tank 21, and the discharged oil from the large diameter forward motion chamber 12A is introduced into the large diameter backward motion chamber 12B, and the piston rod 16 performs high-speed backward motion. .

In this way, the present invention provides a large cylinder body with a large diameter sliding hole and a small cylinder body with a small diameter sliding hole on the same axis, and slides a large diameter piston into the large diameter sliding hole. A large-diameter forward movement chamber and a large-diameter return movement chamber are partitioned by fitting together freely, and a small-diameter piston is slidably fitted into a small-diameter sliding hole to form a small-diameter forward movement chamber and a small-diameter return movement chamber. The large-diameter piston and the small-diameter piston are connected to each other so as to operate integrally, and a piston rod is provided that penetrates and protrudes to the outside from at least either the large cylinder body or the small cylinder body, and supplies pressure oil to the small-diameter reciprocating chamber. One selector valve discharges discharged oil from the small diameter double acting chamber, one flow control valve controls the discharge oil from the small diameter double acting chamber to achieve high speed operation under small loads, and one flow control valve discharges discharged oil from the small diameter double acting chamber under small loads. The other switching valve communicates the forward movement chamber and the large diameter return movement chamber without supplying pressure oil, and supplies pressure oil to the large diameter return movement chamber and discharges discharged oil from the large diameter return movement chamber during heavy loads; This is a hydraulic control device equipped with the other flow control valve that achieves low-speed operation by constricting the oil discharged from the large-diameter double-acting chamber discharged from the other switching valve during heavy loads, and when the load is small, the small-diameter double-acting The oil discharged from the chamber is throttled and controlled by one flow control valve, and when the load is large, the oil discharged from the large diameter reciprocating chamber is throttled and constricted by the other flow control valve to ensure accurate high-speed and low-speed operation. I can do it. In addition, the structure of the cylinder and valve is relatively simple and can be manufactured easily, and it is particularly effective in applications where the load is extremely large and the operation is performed at extremely low speeds.

[Brief explanation of the drawing]

The drawing is a hydraulic circuit diagram showing an embodiment of the present invention together with a partial sectional view. 5...Large cylinder body, 9...Small cylinder body, 10...Large diameter sliding hole, 11...Large diameter piston, 13...Small diameter sliding hole, 14...Small diameter piston, 16...Piston rod , 20, 25... switching valve, 22, 26... flow control valve.

Claims (1)

[Scope of utility model registration request] A large cylinder body with a large diameter sliding hole and a small cylinder body with a small diameter sliding hole are provided on the same axis,
A large-diameter piston is slidably fitted into a large-diameter sliding hole to partition a large-diameter forward movement chamber and a large-diameter backward movement chamber, and a small-diameter piston is slidably fitted into a small-diameter sliding hole. A small-diameter forward movement chamber and a small-diameter return movement chamber are divided and arranged, and the large-diameter piston and the small-diameter piston are connected so as to operate integrally, and the piston protrudes outward from at least either the large cylinder body or the small cylinder body. A piston rod is provided, and a switching valve that supplies pressurized oil to the small-diameter forward-moving chamber and discharges discharged oil from the small-diameter backward-moving chamber, as well as a control valve that throttles and controls the discharged oil from the small-diameter backward-moving chamber under small loads, enables high-speed operation. One flow control valve connects the large-diameter forward motion chamber and the large-diameter reciprocating chamber without supplying pressure oil when the load is small, and supplies pressure oil to the large-diameter forward motion chamber during the large load, resulting in large-diameter double motion. The other switching valve discharges discharged oil from the chamber, and the other flow control valve controls the discharged oil from the large-diameter reciprocating chamber discharged from the other switching valve during heavy loads to achieve low-speed operation. Hydraulic control device.