JP3332990B2 - Relief valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a relief valve structure, and more particularly to a high-pressure relief valve that is pressed by a main valve to open and close the valve by opening and closing the valve seat. The present invention relates to a relief valve capable of sufficiently performing chamber-side pressure control.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional relief valve. This relief valve is a pilot-type leaf-type electromagnetic proportional relief valve, and performs pressure control on the high-pressure chamber 1 side. The high-pressure chamber 1 is connected to, for example, a hydraulic pump. It is assumed that the low-pressure chamber 3 side returns to, for example, a tank. A valve seat 5 is provided on the high pressure chamber 1 side. The leaf valve 7 contacts and separates from the valve seat 5 from the low pressure side to open and close the valve. The main valve 11 urged by the spring 9 presses the leaf valve 7 against the valve seat 5. Behind the leaf valve 7, that is, on the side opposite to the high pressure chamber 1, a pilot chamber 13 is provided.
Is provided. The pilot chamber 13 communicates with the high-pressure chamber 1 through a pilot passage 15. This pilot passage 15 has an orifice 17. The opening and closing and the opening degree between the pilot passage 15 and the low-pressure chamber 3 are controlled by a poppet valve 19. That is, the poppet valve 19 is fixed to the plunger 21 and is an electromagnetic valve capable of adjusting the opening by adjusting the current supplied to the coil 23.

The operation of this conventional example will be described below. pie
The pressure in the lot chamber 13 is controlled by adjusting the degree of opening of the poppet valve 19 by the thrust generated by the solenoid portion 25 composed of the coil 23 and the plunger 21 whose current is adjusted. When the thrust decreases, the pressure of the pilot chamber 13 approaches the tank pressure via the opened poppet valve 19 by the action of the orifice 17 . Therefore, the pressure in the pilot chamber 13 decreases. Then, the balance between the pressure of the high-pressure chamber 1 acting on the leaf valve 7, the pressure of the pilot chamber 13, and the force of the spring 9 is lost, and a gap is easily generated between the leaf valve 7 and the valve seat 5. Communicating with the chamber 3, the pressure in the high-pressure chamber 1 decreases. As a result, the force due to the pressure in the high pressure chamber 1 and the force due to the pressure in the pilot chamber 13 and the force due to the spring 9 are in a state of being balanced, the leaf valve 7 is closed again, and the high pressure chamber 1 is controlled to a predetermined low pressure. . When the thrust by the solenoid portion 25 increases, the pressure in the pilot chamber 13 increases again, and the leaf valve 7 becomes easy to close. Therefore, the pressure in the high-pressure chamber 1 increases to a high predetermined pressure. Thus, the relief valve controls the pressure of the high-pressure chamber 1 to an arbitrary predetermined pressure by changing the thrust of the solenoid portion 25.

[0004]

However, in the structure of the relief valve described above, the pressure in the pilot chamber presses the leaf valve 7 against the valve seat 5, and the pressure in the pilot chamber closes between the leaf valve 7 and the main valve 11. The pressure is only the force of the spring 9. Therefore, it has the following disadvantages. (1) When the force of the spring 9 is weak, the pressing force of the main valve 11 on the leaf valve 7 becomes weak. For this reason, when the processing accuracy of the contact end face of the main valve 11 with the leaf valve 7 is not sufficient, or when the leaf valve 7 is deformed by the opening operation or the like, a gap from the pilot chamber 13 to the low pressure chamber 3 is formed. Easy to occur. Therefore, the pilot room 13
Cannot be maintained at a high pressure. Therefore, the leaf valve 7 opens, and the pressure in the high-pressure chamber 1 cannot be maintained. That is, there is a problem in controlling the pressure of the high-pressure chamber 1 as a function of the leaf valve 7. When the pressure to be controlled on the high pressure chamber 1 side is particularly high, the force of the spring 9 becomes relatively weak, and this disadvantage is remarkable.

(2) Eliminate the disadvantages as described in (1).
When strong force of the spring 9, as a pressure in the pilot chamber 13 is reduced, the pressure in the high pressure chamber 1, which tends to be held by the force of the spring 9, no longer drop to a sufficiently to a low pressure for There can be.
That is, there is a problem in controlling the pressure of the high-pressure chamber 1 as a function of the leaf valve 7 . When the pressure to be controlled in the high-pressure chamber 1 is particularly low, since the force of the spring 9 becomes relatively strong, this disadvantage is remarkable. The present invention has been made in view of the above disadvantages, to provide a relief valve which can prevent that the opening and closing operation of the leaf valve 7 causes a gap due to deformation of the leaf valve 7 is not performed correctly With the goal.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above objects, the present invention provides a housing, a pilot passage formed in the housing and communicating between a high pressure chamber and a low pressure chamber, and a pilot passage provided in the pilot passage. Orifice and
It is provided on the outer periphery of the housing, the leaf valve provided in the distribution process of the high-pressure chamber and the low pressure chamber, together with a slidably provided on the outer periphery of the housing, Bal the leaf valve
A main valve which enables pressing the Bushito, the main
When defined by the in-valve and housing
A pilot chamber communicating with the pilot passage ,
A spring that presses and biases the main valve; and an electromagnetic valve that adjusts an opening between the pilot passage and the low-pressure chamber. The pressure in the pilot chamber acts on the main valve, and the acting force generated by this pressure is applied. The main valve is provided with a thrust in the direction of closing the leaf valve by the elastic force of the spring.

[0007]

When the solenoid valve increases the opening between the pilot passage and the low-pressure chamber, the pressure in the pilot chamber decreases, the pressing force on the main valve decreases, and the leaf valve opens. Conversely, when the opening of the solenoid valve is reduced, the pressure in the pilot chamber increases and the pressing force of the main valve increases, so that the leaf valve closes. Even if there is a gap between the leaf valve and the main valve, the pressure in the pilot chamber does not drop because the leaf valve and the pilot chamber are not in contact as in the related art.

[0008]

An embodiment of the present invention will be described below with reference to FIG. The relief valve of this embodiment is a pilot-type leaf-type electromagnetic proportional relief valve, and has a structure of a rotating body that rotates around a central axis 27. And the circuit on the pump side is the hole 29
Through the high-pressure chamber 1. The circuit on the tank side communicates with the low-pressure chamber 3 through the hole 31. High pressure chamber 1
And the low-pressure chamber 3 each have a substantially ring-shaped space, and a leaf valve 7 opens and closes between these 1 and 3. The leaf valve 7 has a thin ring shape, and opens and closes the valve seat 5 having a ring-shaped opening 33 by being in contact with and away from the low-pressure chamber 3 side. The main valve 11 presses the leaf valve 7 from above (from the right in the figure) the valve seat 5. The main valve 11 has a substantially ring shape, has a seal ring 35 on the inner peripheral surface, and prevents a gap from being generated on the inner peripheral surface due to the movement accompanying the pressing operation. Main valve 11
A cylindrical flange 37 is formed at the back of the coil, and a coiled spring 9 is fitted around the flange 37 to urge the main valve 11 in the pressing direction. The pilot chamber 13 is formed inside the flange 37 between the central housing 39.

A housing 39 is fixed at the center of a case 41 forming the outer shape of the relief valve in the left-right direction in the drawing, and has a substantially columnar shape. A pilot passage 15 is formed in this cylindrical interior, and the high pressure chamber 1 and the pilot chamber 1 are formed.
3 is communicated. An orifice 17 is formed inside the pilot passage 15 . Behind the housing 39, a poppet chamber 43 communicating with the low-pressure chamber 3 is formed, and can communicate with the pilot passage 15.
The communication portion 45 can be opened and closed by the poppet valve 19. Poppet valve 19 is fixed to plunger 21. Plunger 21 is plunger room 47
A hole 49 is provided so as to be able to move back and forth by the gap L in the inside. A coil 23 is provided on the outer periphery of the plunger 21, and forms a solenoid 25 together with the plunger 21. When the coil 23 is energized, the solenoid 25 can generate a thrust for moving the poppet valve 19 forward.

The operation of this embodiment will be described below.
The function of the relief valve is to adjust the opening of the poppet valve 19 by the thrust of the solenoid 25 and control the pressure in the hole 29 of the high-pressure chamber 1. First, when the thrust by the solenoid portion 25 decreases and the opening of the poppet valve 19, which is an electromagnetic valve, increases, the flow rate of oil flowing from the high-pressure chamber 1 to the poppet chamber 43 via the pilot passage 15 increases.
At this time, the pressure of the pilot chamber 13 communicating with the pilot passage 15 decreases due to the function of the orifice 17,
It approaches the tank pressure via the low pressure chamber 3. Then, the pressing force of the main valve 11 generated by the pressure of the pilot chamber 13 decreases, and the force acting on the leaf valve 7 from the high-pressure chamber 1 side relatively increases. A gap is easily generated in the high pressure chamber 1 and the low pressure chamber 3 communicate with each other. Since the high-pressure chamber 1 has the hole 29,
The communication with the low-pressure chamber 3 reduces the pressure in the high-pressure chamber 1. As a result, the force from the high-pressure chamber 1 side becomes relatively small this time, so that the force due to the pressure in the high-pressure chamber 1, the force due to the pressure in the pilot chamber 13, and the force of the spring 9 eventually balance. When the pressure in the high pressure chamber 1 further decreases, the leaf valve 7 closes again, whereby the pressure in the high pressure chamber 1 is controlled to a predetermined low pressure.

Next, when the thrust of the solenoid portion 25 increases and the opening degree of the poppet valve 19 decreases, control is performed to increase the pressure of the high-pressure chamber 1 to a high predetermined pressure. In this manner, the relief valve of the present embodiment increases or decreases the thrust of the solenoid 25 to adjust the opening of the poppet valve 19,
The pressure in the high-pressure chamber 1 can be controlled. By the way, in this embodiment, the pilot chamber 13 is provided in contact with the back of the main valve 11. Therefore, even if a gap is formed in the leaf valve 7 due to deformation or the like, the opening and closing operation as the relief valve can be performed correctly. Can be. Therefore, the force of the spring 9 can be positively reduced as compared with the related art, and the disadvantages (1) and (2) of the related art can be solved. The details will be described below. (1) Even if the force of the spring 9 is weak, not only the pressing force of the leaf valve 7 against the valve seat 5 but also the pressing force of the main valve 11 against the leaf valve 7 can be sufficiently increased. For this reason, the processing accuracy of the contact end face where the main valve 11 comes into contact with the leaf valve 7 is not sufficient, or even if the leaf valve 7 is deformed by opening / closing operation or the like, a gap is hardly generated before and after the leaf valve 7. . Conventionally, a gap is formed in the leaf valve 7 due to the deformation or the like, oil leaks from the pilot chamber 13 (see FIG. 3) to the low-pressure chamber 3, and the pressure in the pilot chamber 13 cannot be maintained at a high pressure. Although the valve was opened, the pressure in the high-pressure chamber 1 could not be maintained as a result. However, in this embodiment, such a disadvantage can be eliminated. Also,
Even if a gap is formed between the leaf valve 7 and the main valve, the pressure in the pilot chamber 13 leaks to the low-pressure chamber 3 through the gap because the leaf valve 7 and the pilot chamber 13 are not in contact with each other. It does not happen. Therefore, the pressure in the pilot chamber 13 is maintained at a high pressure, the leaf valve 7 does not open any more, and does not open as a relief valve. When the pressure of the high-pressure chamber 1 to be controlled is particularly high (control in a high-pressure region), the force of the spring 9 becomes relatively small. Because of the pressure of the pilot chamber 13 as well as the force of the pilot chamber 13, a sufficient pressing force can be obtained, and the malfunction of opening as a relief valve can be eliminated.

(2) Since it is not necessary to increase the force of the spring 9 as described in the above (1), there is no inconvenience caused by increasing the force of the spring 9 as in the prior art. That is, when the pressure of the high-pressure chamber 1 to be controlled is particularly low (control in a low-pressure region), the force of the spring 9 becomes relatively large. Was. In contrast, in the present embodiment,
Since the main valve 11 obtains the pressing force from the pilot chamber 13, when the pressure in the pilot chamber 13 decreases, the pressing force is immediately lost, the relief valve opens, and the pressure in the high-pressure chamber 1 decreases to a predetermined low pressure. In this manner, control in the high-pressure region and the low-pressure region can be sufficiently performed. In FIG. 1, the space 51 between the leaf valve 7 and the main valve 11 may be a closed space, or may be a space open to the low-pressure chamber 3 side. In the case of a closed space, when the leaf valve 7 is opened, the capacity of the space 51 becomes large and a load is easily generated.
A sufficient thickness is set to prevent deformation of the leaf valve 7 due to this load. If you want to reduce the wall thickness,
, The space 51 is opened to the low-pressure chamber 3 side. That is, the notch 53 is provided at a portion where the main valve 11 is in contact with the leaf valve 7 to allow oil to escape.
Thus, even when the leaf valve 7 is opened, the space 51 does not become a negative pressure and deformation can be prevented.

[0013]

As described above, according to the relief valve of the present invention, even if the elastic force of the spring is weak,
By applying the pressure of the chamber to the main valve,
Leaf valve can be closed tightly. did
Thus, the high-pressure chamber can be maintained at a predetermined pressure.
Also, even if a gap due to deformation or the like occurs in the leaf valve, the pilot chamber is not provided in contact with the back of the leaf valve as in the conventional case, and the pressure in the pilot chamber leaks from this gap and decreases. There is no end. Therefore, it is possible to prevent the opening and closing operation of the relief valve from being performed incorrectly due to the gap between the leaf valves.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is an enlarged view of a portion II in FIG.

FIG. 3 is a longitudinal sectional view showing a conventional art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 High pressure chamber 3 Low pressure chamber 5 Valve seat 7 Leaf valve 9 Spring 11 Main valve 13 Pilot chamber 15 Pilot passage 17 Orifice 19 Poppet valve (electromagnetic valve) 21 Plunger 23 Coil 25 Solenoid part 27 Center axis 29 Hole 31 Hole 33 Opening 35 Seal ring 37 Flange 39 Housing 41 Case 43 Poppet chamber 45 Communication part 47 Plunger chamber 49 hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-266669 (JP, A) JP-A-2-2548 (JP, U) JP-A-61-41970 (JP, U) (58) Investigation Field (Int.Cl. ⁷ , DB name) F16K 17/00-17/168 F16K 31/36-31/42

Claims (1)

(57) [Claims] 1. A housing, a pilot passage formed in the housing and communicating the high-pressure chamber and the low-pressure chamber, an orifice provided in the pilot passage, an orifice provided on an outer periphery of the housing, and a high-pressure chamber and a low-pressure chamber. And a leaf valve slidably provided on the outer periphery of the housing, and the leaf valve is provided with a valve.
The main valve that can be pressed against the seat and this main valve
Is defined by the valve and the housing.
A pilot chamber that communicates with the pilot passage, a spring that presses and biases a main valve, and an electromagnetic valve that adjusts an opening degree between the pilot passage and the low-pressure chamber. A relief valve configured to apply a thrust in a direction in which the leaf valve is closed to the main valve by acting on the valve and using an acting force generated by the pressure and an elastic force of the spring.