JPH032721Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention is a pressure fluid circuit that uses an accumulator, and when the pump that generates fluid pressure is stopped, the high-pressure fluid accumulated in the accumulator is related to a discharge valve that automatically discharges water into a tank.

(Prior art) Fluid circuits that send oil and other high-pressure fluids obtained by operating pumps to fluid devices to operate these devices are designed to prevent fluid pressure pulsations and to prevent actuators from instantly pumping large amounts of fluid. Accumulators are used for the purpose of achieving energy-saving circuits in which consuming systems and pumps are turned off and the circuits operate only with accumulated fluid.

When the fluid equipment stops operating, pressure fluid remains in this accumulator and continues to send pressure fluid to the circuit even after the pump is stopped.
If you assume that the pump has stopped and make a mistake, there is a risk that the fluid equipment will start moving, causing an accident or damage to the equipment.

For this reason, in the past, an electromagnetic switching valve was connected to the accumulator, and the switching valve was opened at the same time as the motor driving the pump stopped, and the pressurized fluid in the accumulator was discharged to the tank, or the fluid equipment A discharge valve interlocked with a link or a manual discharge valve is provided to discharge the pressure fluid in the accumulator.

FIG. 3 shows a conventional example of a fluid circuit having an accumulator provided with such a discharge valve. 1 is a fluid tank, 2 is a pump driven by a motor 3, 4
is an unloading valve that short-circuits the fluid to tank 1 when the pressure in the fluid circuit becomes high due to a temporary stop of fluid equipment, 5 is a check valve, 6 is a fluid equipment driven by pressure fluid, and 7 is an accumulator. , 8 is a check valve, 9 is a variable orifice, and 10 is a discharge valve.
In this conventional example, the discharge valve 10 is a solenoid valve.

In this circuit, the pressure fluid discharged from the pump 2 passes through the check valve 5 and is then divided into two parts, one being sent to the fluid device 6 and the other being sent to the accumulator 7 through the check valve 8. and accumulated. The pressure fluid in the accumulator is sent to the fluid device 6 through the orifice 9 as necessary to prevent fluid pressure pulsations and to drive the fluid device.

When the use of the fluid equipment is stopped and the motor 3 and pump 2 are stopped, a discharge valve 10 electrically interlocked with the discharge valve 10 opens to discharge the pressure fluid from the accumulator 7 to the tank 1. As the discharge valve, in addition to the electromagnetic valve electrically linked to the motor 3 as described above, a manual discharge valve that is manually opened and closed, and a discharge valve that is mechanically linked to the moving part of the hydraulic equipment are used. There is.

(Problems to be solved by the invention) If these conventional devices operate automatically, they must be equipped with an electric control system or link mechanism, making the devices complicated and expensive. The disadvantage is that the operation is cumbersome and operation errors are likely to occur.

This invention aims to provide a discharge valve that can automatically discharge the pressure fluid in the accumulator to the tank only by the valve mechanism when the accumulator is not in use.

(Means for solving the problem) This invention consists of a piston 1 provided with a valve 19 at one end.
8, a first passage 12 connected to the pump 2 and the accumulator 7, and a valve 19 having one end formed in the piston 18, which is opened and closed by a valve 19 to control communication with the cylinder hole 21. A second passage 14 with a smaller diameter than the cylinder hole 21, a second passage 1
A third passage 16 that communicates the cylinder hole 21 with the tank 1 and a fourth passage 17 that communicates the cylinder hole 21 with the tank 1 are formed in the valve body 11. The valve 19 is configured to have an elastic force of a compression spring 20 strong enough not to prevent the valve 19 from moving toward the second passage 14 together with the piston 18 due to discharge fluid pressure in a direction that moves the valve 19 away from the second passage 14. The above-mentioned problems have been solved by providing an eumulator discharge valve.

(Function) When the pump is in operation, the discharged fluid pressure enters the cylinder hole 21 through the first passage 12, pushes the piston 18 toward the second passage 14 against the compression spring 20, and is released by the valve 19. One end of the second passage 14 is closed. The same fluid pressure enters from the other end of the second passage 14 through the third passage 16 and pushes the valve 19 in the opposite direction, but since the pressure receiving area of the piston 19 is much larger, this fluid pressure Even with the elasticity of the spring 20, the valve 19 will not open, and the fluid discharged from the pump will not be returned to the tank through the fourth passage 17.

When the pump is stopped, the fluid pressure in the first passage 12 decreases, and since the fluid pressure from the accumulator 7 is not applied due to the check valve 5, the piston 18
The force that pushes the object toward the second passage 14 becomes weaker. Then, the piston moves into the first passage 12 due to the compression spring 20.
Pushed to the side, valve 19 opens second passage 14 . As a result, the pressure fluid in the accumulator 7 is discharged from the fourth passage 17 to the tank 1.

(Example) First Example: Figure 1 is a vertical sectional view schematically showing the first example of the accumulator discharge valve of the present invention, and is an example in which a constant flow type pump 2 is used. Other related devices of the circuit are also schematically shown.

The left end of the valve body 11 is provided with a cylinder hole 21 whose right end is closed, and the lid 13 having the first passage 12 leading to the pump 2 is screwed to close the left end. A valve seat piece 15 having a second passage 14 smaller than the cylinder hole 21 is screwed onto the valve seat piece 15 . A third passage 16 that communicates the second passage 14 with the accumulator 7 is provided at the right end of the valve body;
A fourth passage 17 is provided that allows the second passage 14 to communicate with the fluid tank 1 through the cylinder hole 21.
The cylinder hole 21 has a deep dish-shaped piston 18 that opens on the right side, and a valve 1 that fits inside the piston 18.
9, and this valve 19 and piston 18 are connected to the valve seat piece 1.
A compression spring 20 is housed therein, which acts to separate the body from the body. Piston 18 and valve 19 may be formed integrally. The solid and dashed lines connecting the parts indicate conduits. The operation of the discharge valve of this first embodiment is as follows.

The motor 3 drives the pump 12 to discharge a fixed amount of pressure fluid, which pushes open the check valve 5 and is supplied to the fluid device 6 and the accumulator 7, while passing through the first passage 12 of the lid 13. It joins piston 18 and moves it to the right in FIG. 1 against spring 20. As a result, the valve 19 comes into contact with the valve seat piece 15 and closes the second passage 14.

At the beginning of the pump operation, the piston 18 and the valve 19 are pushed by the spring 20 and move to the left, so pressure fluid enters the cylinder hole 21 from the third passage 16 through the second passage 14. However, since the fluid passes through the second passage 14, which has a small diameter, its pressure decreases and is discharged into the tank 1 through the fourth passage 17, which pushes the piston 18 to the left with a strong force. Never. On the other hand, strong fluid pressure from the pump 2 acts on the left end surface of the piston 18 through the first passage 12 and pushes the piston 18 to the right against the spring 20.
9 moves to the right and the valve 19 closes the second passage 14. In this state, the fluid pressure is acting strongly on the left end surface of the piston 18, while the fluid pressure acting on the valve 19 is on the cross-sectional area of the second passage 14, which has a smaller diameter than the piston 18. A correspondingly weaker fluid pressure acts in the opposite direction, and although the compression spring 20 also pushes the valve 19 to the left, the fluid pressure pushing the piston 18 to the right is greater, and eventually the pump 2
During operation, the second passage 14 remains closed and no pressure fluid is discharged into the tank 1 through the fourth passage 17.

When the motor 3 and pump 2 are stopped to stop the operation of the fluid equipment, the fluid pressure that pushes the piston 18 to the right disappears, so the accumulator 7
Fluid pressure entering second passageway 14 from and spring 20
Therefore, the piston 18 and the valve 19 move to the left, the second passage 14 is unclosed, and the pressure fluid accumulated in the accumulator is transferred from the second passage 14 to the cylinder hole 2.
1 and further passes through the fourth passage 17 to the tank 1.
is discharged to. Working area of piston 18 and passage 1
The ratio of 4 to the cross-sectional area is set to be as high as, for example, 140:1 in order to effectively perform the above action.

In this manner, this discharge valve automatically moves the piston 18 and valve 19 by utilizing the difference in fluid pressure, and does not require any accessory devices such as an electric control system or a link mechanism.

Second Embodiment: FIG. 2 shows an embodiment of the present invention in which the above-mentioned discharge valve 10, unloading valve 4, and check valve 5 are assembled into one valve body 11 so that the piping connecting these can be omitted. A second example is shown. In this example,
A pilot valve 30 and a balance valve 31 constitute an unloading valve 4. An unloading valve having this configuration has been commonly used in the past. The second embodiment utilizes this known unloading valve and incorporates the accumulator discharge valve 10 into the valve body 11 together with this known unloading valve. Since the structure, operation, etc. of the accumulator discharge valve 10 are the same as those in the first embodiment shown in FIG. 1, the same parts as those in FIG. Let me explain this.

An inlet passage 32 communicating with the constant flow pump 2 is vertically connected to the valve body 11, and a check valve 5 is provided at the upper end of the inlet passage 32. The check valve 5 includes a valve cylinder 33 tightly screwed onto the valve body 11 at the upper end of the passage 32.
A valve piece 34 is fitted into the valve body, and this is pressed toward a valve seat formed in the valve cylinder by a compression spring 36 held down by a support piece 35 screwed onto the upper end of the valve cylinder. The fluid that has ascended the inlet passage 32 and pushed open the valve piece 34 exits from the hole 37 on the side surface of the valve cylinder to the third passage 16 and flows toward the fluid device 6 and the accumulator 7 .

The accumulator discharge valve 10 of the present invention allows the second passage 14 to communicate with the intersection of the third passage 16 and the inlet passage 32, and the surface of the piston 18 opposite to the second passage 14 is connected to the first passage 14. Entrance passage 3
It leads to 2. The cylinder hole 21 communicates with the tank 1 through a fourth passage 17.

Since the check valve 5 and the discharge valve 10 are configured in this manner, when the pump 2 is operated, the piston 18 is pushed to the left in FIG. is closed by a valve 19, and when the pump is stopped, this passage 14 is opened by a spring 20, and the pressure fluid of the accumulator 7 is discharged to the tank 1 through the third passage 16, the second passage 14, the cylinder hole 21, and the fourth passage 17. can do.

In the pilot valve 30 of the unloading valve 4, a piston 39 which connects a large diameter part 39a and a small diameter part 39b is provided by fitting each part 39a, 39b into a large and small cylinder.
Fluid pressure is applied to a through the third passage 16 to the fifth passage 38, and the inlet passage 32 is applied to the small diameter portion 39b.
Fluid pressure is applied through the sixth passage 40. Since the fluid pressure applied to the large diameter portion 39a is greater than the fluid pressure pushing the small diameter portion 39b, the piston 39 moves to the right and the rod 42 protruding from the right end hits the ball 43, but the piston 39 pushes the ball 43. Since the force of the spring 44 is greater than the differential pressure that causes the piston 39 to move to the right, the ball 43 is pushed by it and blocks the seventh passage 45. 46 is an adjustment screw for adjusting the elasticity of the spring 44. When the discharge fluid pressure of the pump 2 is normal, the ball 43 closes the seventh passage 45 in this manner.

The balance valve 31 has a valve piece 4 pressed by a spring 47.
8 is seated on a valve seat 49 formed on the side of the inlet passage 32, and normally closes the eighth passage 50. The inside of the hollow valve piece 48 communicates with the inlet passage 32 through a small diameter hole 51. Further, since the annular portion 52 on the outer periphery of the right conical end of the valve piece 48 is exposed within the inlet passage 32, the discharge fluid pressure of the pump is applied thereto. The fluid pressure of the pump is applied to the left end of the valve piece 48 through the sixth passage 40, the space 53 within the pilot valve, and the ninth passage 54. Since the fluid pressure pushing the valve piece 48 to the right is greater than the fluid pressure pushing the annular portion 52 at the right end of the valve piece leftward, the valve piece 48 seats on the valve seat 49 and blocks the eighth passage 50. The discharge fluid of the pump does not flow into the eighth passage 50.

When the fluid pressure in the inlet passage 32 and other parts increases, such as when the fluid device 6 is stopped while the pump 2 is operating, the large diameter portion 39a of the piston 39 increases.
The fluid pressure pushing the small diameter part 39 to the right increases.
The seventh passage 45 is opened by pushing the ball 43 with the rod 42 against the fluid pressure applied to b and the elasticity of the spring 44. Since the seventh passage 45 communicates with the tank 1 through the tenth passage 55, the fluid pressure pushing the valve piece 48 of the balance valve 31 to the right is the same as that of the ninth passage 55.
4, the space 53, the seventh passage 45, and the tenth passage 55 before being discharged to the tank 1. As a result, the fluid pressure acting on the annular portion 52 that pushes the valve piece 48 to the left becomes stronger, the valve piece 48 moves to the left, the inlet passage 32 and the eighth passage 50 communicate, and the discharge fluid pressure of the pump increases. is returned to the tank to prevent pressure build-up.

Fluid continues to enter the valve piece 48 through its small diameter hole 51, but since it takes time to fill the inside of the valve piece 48 as it passes through the small diameter hole, the above-mentioned movement of the valve piece to the left is faster, and then The action of pushing the valve piece 48 to the right disappears.

When the fluid pressure no longer rises excessively, pilot valve 3
The ball 43 closes off the seventh passage 45 due to the spring 44 because the large fluid pressure that moves the zero piston 39 to the right is gone. Then, the sixth passage 40, space 5
3. Fluid enters the left side of the valve piece 48 through the ninth passage 54 and the small diameter hole 51 of the valve piece 48, pushes the valve piece 48 and seats it on the valve seat 49, and the discharge fluid pressure of the pump increases. The effect of returning the water to the tank disappears.

(Effects of the invention) (1) When the pump is stopped, the pressure fluid accumulated in the accumulator is automatically discharged to the tank, eliminating the need to operate a manual valve. Therefore, there is no risk of operating errors.

(2) Automatic pressure fluid discharge can be performed more easily than devices that automatically discharge pressure fluid from an accumulator using an electrical control system or link mechanism.

(3) Therefore, an automatic pressure fluid discharge device can be manufactured at low cost.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention, and Figure 1 is a vertical cross-sectional view showing the first embodiment of the present invention when a constant flow type pump is used, and other related equipment is also schematically shown. ing. Fig. 2 is a longitudinal cross-sectional view of a second embodiment of the present invention, showing an example in which a discharge valve is assembled into an integrated valve body together with a check valve, etc., and Fig. 3 is a diagram of a fluid circuit for a fluid device having an accumulator. It is a schematic diagram showing a conventional example. 1: Fluid tank, 2: Pump, 3: Motor,
4: Unloading valve, 5: Check valve, 6: Fluid equipment, 7: Accumulator, 8: Check valve, 9:
Variable orifice, 10: Discharge valve, 11: Valve body, 12: First passage, 13: Lid, 14: Second passage, 15: Valve seat piece, 16: Third passage, 17: Fourth passage, 18: Piston , 19: Valve, 20: Compression spring, 21: Cylinder hole, 24, 25: Lid, 26:
Cylinder, 27: Side hole, 28: Piston valve, 2
9: Spring, 30: Pilot valve, 31: Balance valve, 32: Inlet passage, 33: Valve cylinder, 34: Valve piece,
35: Support piece, 36: Compression spring, 37: Hole, 3
8: Fifth passage, 39: Piston, 39a: Large diameter part, 39b: Small diameter part, 40: Sixth passage, 42:
Rod, 43: Ball, 44: Spring, 45: Seventh passage, 46: Adjustment screw, 47: Spring, 48: Valve piece,
49: Valve seat, 50: Eighth passage, 51: Small diameter hole, 5
2: Annular part, 53: Space, 54: Ninth passage, 5
5: Tenth passage.

Claims (1)

[Scope of utility model registration request] A cylinder hole 21 into which a piston 18 having a valve 19 at one end is fitted, a pump 2 and an accumulator 7
a first passage 12 connected to the piston 1 at one end;
A second passage 14 having a smaller diameter than the cylinder hole 21 is opened and closed by a valve 19 formed in the cylinder hole 21 to control communication with the cylinder hole 21; Three aisles 1
6, and a fourth passage 17 that communicates the cylinder hole 21 with the tank 1 is formed in the valve body 11, and the valve 19
In order to separate this valve 19 from the second passage 14, the elasticity of the compression spring 20 is strong enough not to prevent the valve 19 from moving toward the second passage 14 together with the piston 18 due to the discharge fluid pressure of the pump 2. Accumulator discharge valve configured in addition to direction.