JPH0341135Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is applicable to the opening and closing of the circuit and the pressure of the fluid flowing through the circuit in which a large flow rate flows, such as the hydraulic circuit of a large press machine. The present invention relates to a device that also performs flow rate control with compensation.

(Prior art) Conventionally, in hydraulic circuits where a large flow rate of about 300/min or more flows, a pressure compensation system has been used to maintain a constant flow rate even if the pressure on the primary and secondary sides of the circuit changes. If flow control is required and the circuit also needs to be opened/closed, connect the secondary side a connected to the pump and the secondary side b connected to an actuator such as a hydraulic cylinder as shown in the first diagram. The circuit c is generally configured by providing a spool-type on-off valve d and a plurality of parallel flow control valves e. Since it is difficult to manufacture a single flow control valve e with a large flow rate, a plurality of flow control valves are designed so that the total flow rate becomes the desired flow rate of the circuit c. Furthermore, a logic valve having a cartridge-type seat-type valve configuration has been known for a long time as a valve that can flow a large flow rate despite its size and can be embedded in a valve block.

(Problem that the invention attempts to solve) Spool-type on-off valves for large flow rates are large;
This is combined with a plurality of flow control valves, for example two flow control valves, to form one valve block,
/min, the overall dimensions are relatively large, about 25 cm long, 25 cm wide, and 30 cm high, requiring a large installation space, and each piece of equipment is expensive. It's inconvenient.

The object of the present invention is to provide a flow rate regulating device for large flow rates that uses a logic valve and has an opening/closing function and a pressure compensation function that can be manufactured in a small size and at low cost.

(Means for solving the problem) In the present invention, a main circuit is formed in a small metal block in which an inlet and an outlet are formed, and a main circuit is formed from the inlet to the outlet, through which a large amount of flow flows. , the main circuit is provided with a poppet on which the pressure of the inlet is applied on the front side, and on the back side of which the pressure of the pilot circuit controlled by a flow controller and a sequence valve and the force of a spring are applied, and when the poppet is actuated, A pressure compensating logic valve that changes the area of the main circuit is provided, and the pressure of the main circuit controlled by the pressure compensating logic valve is placed in front of the main circuit between the pressure compensating logic valve and the outlet. A logic valve for throttle control is provided on the rear surface of the valve, which is equipped with a poppet to which the inlet pressure or tank pressure acts via a pilot on-off valve.

(Function) A large flow rate pump is connected to the inlet formed in the small block, and the inlet is connected to the outlet connected to the actuator via the main circuit within the block. When flowing a large flow rate from the inlet to the outlet, first operate the pilot on-off valve to cut off the pressure at the inlet acting on the back of the poppet of the throttle control logic valve, and apply tank pressure to it.
The poppet is retracted by the pressure of the inlet acting on its front surface. As a result, a large amount of flow flows from the inlet to the outlet via the pressure compensation logic valve and the throttle control logic valve. If the pilot on-off valve is returned to its original position in this state, the pressure of the inlet acts on the poppet, and the throttle control logic valve closes the main circuit.
These logic valves are relatively small and can flow a large flow rate, and can be embedded within the block.The pilot on-off valve only controls a small flow rate to the poppet of the throttle control logic valve, so it is compact. You can. In addition, pressure compensation is required to prevent the inconvenience of changing the flow rate flowing through the main circuit due to changes in the pressure at the inlet or outlet. A flow controller and a sequence valve are provided, and the pressure and flow rate controlled by the flow controller and sequence valve are introduced to the back of the poppet of the pressure compensating logic valve, and a certain difference is established in the fluid in the main circuit flowing through the poppet. This is done by actuating it to create pressure.
Since the flow rate through the pilot circuit is small, small flow controllers and sequence valves can be used.

The flow controller maintains a constant flow rate to the back side of the poppet of the pressure compensating logic valve even if the pressure at the inlet or outlet changes, and the sequence valve maintains a constant flow rate when the pressure acting on the back side of the poppet changes. The pressure is controlled so that only a constant pressure is higher than the pressure. A logic valve for pressure compensation is equal to the value obtained by dividing the pressure on the front surface of its poppet by the sum of the force due to the pressure controlled by the sequence valve acting on the rear surface and the spring force by the area of the front surface. Since the differential pressure between the back pressure of the poppet and the pressure at the outlet is constant, the differential pressure in the main circuit before and after the poppet of the logic valve for throttle control is also kept constant, and the pressure difference for the throttle control logic valve is kept constant. Since the opening area of the poppet of the logic valve can also be maintained constant, the flow rate through the main circuit remains constant regardless of pressure changes at the inlet and outlet.

(Example) An example of the present invention will be explained with reference to FIG.
is a small metal valve block that forms an inlet 2 and an outlet 3; 4 is a main circuit formed within the block 1; a large flow rate flows through the main circuit 4 from a pump connected to the inlet 2; and is supplied to an actuator connected to the outlet 3.

5 is a normally open pressure compensation logic valve provided in the main circuit 4; 6 is a throttle control logic valve provided between the logic valve 5 and the outlet 3;
Each logic valve 5, 6 has a movable poppet 5a,
It has 6a. The pressure compensating logic valve 5 has a main circuit 4 connected to the inlet 2 opened laterally, and the opening area of the opening 7 can be varied by moving the poppet 5a. The main circuit 4 continues through the poppet 5a of the valve 5 to the front of the poppet 6a of the throttle control logic valve 6. The poppet 6a of the throttle control logic valve 6 has a stepped portion for opening and closing the main circuit 4.

A pilot circuit 8 connects the inlet 2 and the inlet 3, and the circuit 8 is provided with a small flow controller 9 and a sequence valve 10 for controlling the small flow rate flowing therethrough. circuit 8
a to the chamber 19 facing the back of the poppet 5a 11
was introduced via a branch circuit 12 with a

Reference numeral 13 denotes a pressure introducing circuit that introduces the pressure of the inlet 2 or the pressure of the tank 14 to the back of the poppet 6a of the throttle control logic valve 6. By switching the small pilot on-off valve 15 provided in this, the poppet 6a can be controlled. The pressure of the inlet 2 acts on the back side of the poppet 6a, which connects the main circuit 4 to the pressure compensating logic valve 5.
When the poppet 6a moves forward to stop the flow from the main circuit 4 to the outlet 3, or when the pressure of the tank 14 is applied, the poppet 6a moves back due to the pressure of the main circuit 4 acting on its front surface and opens, allowing the fluid to flow through the main circuit 4. . 16
1 is a limiter that limits the opening of the poppet 6a;
7 is a fixed aperture.

When the pilot on-off valve 15 is switched to the position 15a, the poppet 6a of the throttle control logic valve 6 moves back until it comes into contact with the limiter 16, allowing a large flow to flow through the main circuit 4. Since a constant flow rate is flowing through the pilot circuit 8 and its pressure is controlled by the sequence valve 10, the pressure compensating logic valve 5 controls the main flow from this to the throttle controlling logic valve 6. The fluid pressure in the circuit 4 is controlled to the pressure obtained by multiplying the front and rear area ratio of the poppet 5a by the pressure acting on its back surface, and adding to that value the value obtained by dividing the force of the spring 18 by the area of its front surface. . Further, the pressure difference between the back surface of the poppet 5a and the outflow port 3 is constant, the pressure difference across the throttle control logic valve 6 is always kept constant, and the opening area of the logic valve 6 is controlled by the limiter 16. Since it is constant, the flow rate passing through the main circuit 4 is the inlet 2,
The pressure is kept constant regardless of pressure changes at the outlet 3.
Each logic valve 5, 6 can be configured as a small cartridge with a diameter of about 6.0 cm and a height of about 8.5 cm even at a large flow rate of 450/min, and can be fully embedded in a small block 1 of 15 x 15 x 15 cm. Since the flow controller 9, sequence valve 10, and pilot on-off valve 15 can be small ones for small flow rates, block 1
As shown in FIG. 3A, it can be installed compactly, and it can be much smaller than the conventional product with the same performance as shown in FIG. 3B.

It should be noted that the set pressure of the sequence valve 10 can be adjusted externally, and the differential pressure generated by the throttle control logic valve 6 can be changed. The pressure difference between the inlet and outlet ports 2 and 3, which was constant at around 5 Kgf/cm ² , can now be maintained at, for example, 70 Kgf/cm ² between the inlet and outlet ports 2 and 3, making it possible to control even larger flow rates.

(Effects of the invention) As described above, according to the invention, a main circuit through which a large flow flows is formed in a small block, and logic valves for pressure compensation and throttle control are interposed in this, and a small flow controller and a sequence valve are installed. The pressure compensation logic valve is controlled by the fluid in the pilot circuit controlled by the pilot circuit, and the throttle control logic valve is controlled by the small pilot opening/closing valve. The flow can be controlled, the entire large flow rate regulating device can be made compact, it can be installed in a narrow space, and it is inexpensive because multiple large and expensive flow control valves and switching valves are not used. be.

[Brief explanation of drawings]

FIG. 1 is a diagram of a conventional device, FIG. 2 is a diagram of an embodiment of the present invention, and FIG. 3 is a dimensional comparison diagram of the device of the present invention and the conventional device. DESCRIPTION OF SYMBOLS 1...Block, 2...Inflow port, 3...Outlet port, 4...Main circuit, 5...Logic valve for pressure compensation, 5a...Poppet, 6...Logic valve for throttle control, 6a...Poppet , 8...Pilot circuit, 9...Flow controller, 10...Sequence valve, 15...Pilot opening/closing valve.

Claims (1)

[Scope of utility model registration request] In a small metal block that has an inlet and an outlet, a main circuit is formed from the inlet to the outlet, through which a large flow of water flows. A pressure compensating logic valve, which has a poppet on its back surface to which the pressure of a pilot circuit controlled by a flow controller and a sequence valve and the force of a spring act, and which changes the area of the main circuit by the operation of the poppet. The pressure of the main circuit controlled by the pressure compensating logic valve acts on the front side of the main circuit between the pressure compensating logic valve and the outflow port, and the pressure of the inlet is applied to the back side via a pilot on-off valve. A flow rate regulating device for large flow rates having an opening/closing function and a pressure compensation function, characterized in that it is provided with a logic valve for throttle control equipped with a poppet on which pressure or tank pressure acts.