JPH06294474A - Relief valve - Google Patents

Abstract

PURPOSE:To provide a pilot leaf type electromagnetic proportional relief valve capable of correctly performing opening/closing actions as the relief valve even when a leaf valve is deformed to generate a gap. CONSTITUTION:When the opening of a poppet valve 19 is large, the pressure of a pilot chamber 15 communicated with a low-pressure chamber 3 is lowered, the pressing force of a main valve 11 is reduced, and a leaf valve 7 is opened. When the opening of the poppet valve 19 is small on the contrary, the pressure of the pilot chamber 15 rises, the pressing force of the main valve 11 is increased, and the leaf valve 7 is closed. The pilot chamber 15 is provided behind the main valve 11 via a plunger 37, the pressure of the pilot chamber 15 is not leaked from the gap of the leaf valve 7 even if it is generated, and opening/ closing actions of the main valve 11 are not erroneously performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a relief valve, and more particularly, to a gap between a leaf valve and a main valve that are pressed by a main valve to come into contact with and separate from a valve seat to open and close the valve. The present invention relates to a relief valve capable of sufficiently controlling the pressure on the high pressure chamber side.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional relief valve. This relief valve is a pilot type leaf-type electromagnetic proportional relief valve, and controls the pressure on the high pressure chamber 1 side. The high-pressure chamber 1 side is connected to, for example, the hydraulic pump side. The low-pressure chamber 3 side returns to the tank, for example. 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 biased by the spring 9 presses the leaf valve 7 against the valve seat 5. Behind the leaf valve 7, that is, on the opposite side of the high pressure chamber 1, the pilot chamber 13
Is provided. The pilot chamber 13 communicates with the high pressure chamber 1 through a pilot passage 15. The pilot passage 15 has an orifice 17. A poppet valve 19 opens and closes and adjusts the opening between the pilot passage 15 and the low pressure chamber 3. That is, the poppet valve 19 is fixed to the plunger 21, and is an electromagnetic valve capable of adjusting the opening degree by adjusting the current supplied to the coil 23.

The operation of this conventional example will be described below. The pressure in the pilot chamber 1 is controlled by adjusting the opening degree of the poppet valve 19 by the thrust generated by the solenoid portion 25 including the coil 23 whose current is adjusted and the plunger 21. When the thrust is reduced, the pressure in the pilot chamber 13 is increased by the action of the orifice 17 to open the poppet valve 1
Approaching tank pressure via 9, therefore pilot chamber 1
The pressure of 3 drops. Then, the balance between the pressure on the high pressure chamber 1 side acting on the leaf valve 7, the pressure in the pilot chamber 13 and the force by the spring 9 is lost, and a gap is apt to be formed between the leaf valve 7 and the valve seat 5, and the high pressure chamber 1 is at a low pressure. The pressure in the high pressure chamber 1 is reduced by communicating with the chamber 3. As a result, this time, 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 due to the spring 9 are balanced, the leaf valve 7 is closed again, and the high pressure chamber 1 is controlled to a low predetermined pressure. . When the thrust force of the solenoid portion 25 increases, the pressure in the pilot chamber 13 rises again and the leaf valve 7 is easily closed, so that the pressure in the high pressure chamber 1 rises to a high predetermined pressure. In this way, 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 above relief valve structure, the pressure in the pilot chamber presses the leaf valve 7 against the valve seat 5, and the pressure between the leaf valve 7 and the main valve 11 is closed. The pressure is only the force of the spring 9. Therefore, it has the following drawbacks. (1) When the force of the spring 9 is weak, the pressing force of the main valve 11 against the leaf valve 7 becomes weak. Therefore, when the machining accuracy of the contact end surface between the main valve 11 and the leaf valve 7 is not sufficient, or when the leaf valve 7 is deformed due to the opening operation or the like, a gap from the pilot chamber 13 to the low pressure chamber 3 is generated. It is easy to occur. Therefore, the pilot room 13
It becomes impossible to keep the pressure at high pressure. Therefore, the leaf valve 7 is opened and the pressure in the high pressure chamber 1 cannot be maintained. That is, there is an inconvenience in the pressure control of the high pressure chamber 1 which is the function of the leaf valve 7. Particularly, 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 inconvenience is remarkable.

(2) When the force of the spring 9 is increased in order to eliminate the inconvenience as described in (1), even if the pressure in the pilot chamber 13 becomes small, the pressure in the high pressure chamber 1 is The power of 9 makes it easier to hold,
It is possible that the low pressure does not fall sufficiently. That is, the high pressure chamber 1 which is the function of the relief valve 7.
This causes inconvenience in the pressure control. When the pressure to be controlled on the side of the high pressure chamber 1 is particularly low, the force of the spring 9 becomes relatively strong, and this inconvenience is remarkable. The present invention has been made in view of the above drawbacks, and an object of the present invention is to provide a relief valve that can prevent the leaf valve from being opened and closed incorrectly due to a gap caused by deformation of the leaf valve. And

[0006]

In order to achieve the above object, the present invention provides a leaf valve which is opened and closed by contacting with and separating from a low pressure chamber side of a valve seat provided on the high pressure chamber side, and from above the leaf valve. A main valve to be pressed, a pilot chamber provided behind the main valve via a plunger, a pilot passage having an orifice communicating the pilot chamber with the high pressure chamber, and an opening degree between the pilot passage and the low pressure chamber And a spring for urging the main valve in the pressing direction.

[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 of the main valve decreases, and the leaf valve opens. On the contrary, when the opening degree of the solenoid valve is reduced, the pressure in the pilot chamber rises and the pressing force of the main valve increases, so that the leaf valve closes. Even if a gap is created between the leaf valve and the main valve, the leaf valve and the pilot chamber are not in contact with each other as in the conventional case, so that the pressure in the pilot chamber does not drop.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. The relief valve of the present embodiment is a pilot-type leaf-type electromagnetic proportional relief valve, and has a structure of a rotating body that rotates around the central axis 27. And the circuit on the pump side has a hole 29
Is communicated with the high-pressure chamber 1 via. The tank-side circuit 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 the leaf valve 7 opens and closes between these 1 and 3. The leaf valve 7 has a thin ring shape, and opens and closes with respect to the valve seat 5 having the ring-shaped opening 33 by contacting and separating from the low pressure chamber 3 side. The main valve 11 presses the valve seat 5 from above the leaf valve 7 (from the right in the figure). The main valve 11 is ring-shaped and has a substantially L-shaped cross section. A plunger 37 is provided behind the main valve 11 via a ring-shaped spacer 35. Six of the plungers 37 are arranged at equal intervals in the circumferential direction, and each of them is slidable in each of the six holes similarly formed in the ring-shaped case 39. A spring 9 is provided on the back surface of the plunger 37 via a ring-shaped support 41 to urge the pressing direction. The spring 9 is provided between the spring 43 and the cap 43. The pilot chamber 13 is formed between the case 39 and the cap 43, and the plunger 37 is pushed in the pressing direction by the internal pressure.

The pilot chamber 13 communicates with the high pressure chamber 1 through a pilot passage 15. That is, the substantially cylindrical guide 4 penetrating the centers of the ring-shaped members 11 and 39.
5, a passage 47 is formed inside. This passage 4
7 communicates with the high pressure chamber 1 through an orifice passage 53 via a chamber 51 between the guide 45 and the housing 49. These 47, 51, 53 form the pilot passage 15. The orifice 17 is provided in the orifice passage 53. A poppet chamber 55 communicates with the chamber 51. The poppet valve 19 provided in the poppet chamber 55 can open and close the communicating portion 57. The low pressure chamber 3 is provided in the poppet chamber 55 by the passage 59.
Are communicated with each other, the poppet valve 19 receives the high pressure of the chamber 51 at the tip thereof, and always receives the force of retreating in the left direction in the drawing. A plunger 21 is in contact with the back surface of the poppet valve 19, and the thrust force for moving the poppet valve 19 forward (to the right in the drawing) can be adjusted by the amount of electricity supplied to the solenoid portion 60. The housing 49, the valve seat 5 and the like are housed in a casing 63 of the entire device via an O-ring 61. The leaf valve 7 is provided on the outer periphery of the guide 45 supported in the center of the housing 49 and the valve seat 5.
The valve guide 65 of the main valve 11, the case 39, the cap 43, etc. are fitted. The leaf valve 7 is attached by being sandwiched between the valve seat 5 and the valve guide 65 via a canzer 67. Also, the spacer 35 and the support 41 are each ring-shaped,
The six plungers 35 arranged in the circumferential direction are prevented from moving apart.

The operation of this embodiment will be described below.
The function of this relief valve is to adjust the opening of the poppet valve 19 by the thrust of the solenoid portion 60 and control the pressure in the hole 29 of the high pressure chamber 1. First, when the thrust force by the solenoid portion 60 decreases and the opening degree of the poppet valve 19 which is a solenoid valve increases, the flow rate of oil flowing from the high pressure chamber 1 side to the poppet chamber 45 via the pilot passage 15 increases.
At this time, the pressure of the pilot chamber 13 communicating with the pilot passage 15 is lowered by the action of the orifice 17,
The tank pressure is approached via the low pressure chamber 3. Then, the pressing force of the main valve 11 generated via the plunger 37 due to the pressure in the pilot chamber 13 becomes small, and the force acting on the leaf valve 7 from the high pressure chamber 1 side becomes relatively large, and the leaf valve 7 and the valve A gap is easily generated between the seat 5 and 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 pressure in the high pressure chamber 1 is lowered by communicating with the low pressure chamber 3. As a result, the force from the high-pressure chamber 1 side becomes relatively small this time, and eventually 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 due to the spring 9 are balanced. When the pressure on the high pressure chamber 1 side further decreases, the leaf valve 7 is closed again, and the pressure in the high pressure chamber 1 is controlled to a low predetermined pressure.

Next, when the thrust of the solenoid portion 60 is increased and the opening degree of the poppet valve 19 is reduced, the pressure in the high pressure chamber 1 is controlled to a high predetermined pressure. In this way, the relief valve of the present embodiment adjusts the opening degree of the poppet valve 19 by increasing / decreasing the thrust of the solenoid portion 60.
The pressure in the high pressure chamber 1 can be controlled. In this embodiment, since the pilot chamber 13 is provided behind the main valve 11 via the plunger 37, even if the leaf valve 7 has a gap due to deformation or the like, the opening / closing operation as a relief valve can be performed. You can do it right. Therefore, the force of the spring 9 can be positively weakened as compared with the prior art, and the drawbacks (1) and (2) of the prior art can be eliminated. Less than,
explain in detail. (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, even if the processing accuracy of the contact end surface where the main valve 11 contacts the leaf valve 7 is not sufficient, or even if the leaf valve 7 is deformed due to the opening / closing operation or the like, a gap is unlikely to occur before and after the leaf valve 7. . Conventionally, a gap is created in the leaf valve 7 due to the deformation or the like, oil leaks from the pilot chamber 13 (see FIG. 2) to the low pressure chamber 3, and the pressure in the pilot chamber 13 cannot be maintained at a high pressure, so that the leaf valve 7 opens. Although there is a problem that the valve is opened and, as a result, the pressure in the high pressure chamber 1 cannot be maintained, such a problem can be eliminated in the present embodiment. Also,
Even if a gap occurs between the leaf valve 7 and the main valve 11, the leaf valve 7 and the pilot chamber 13 are not in contact with each other, so that the pressure in the pilot chamber 13 leaks to the low pressure chamber 3 side through the gap. There is no chance of doing it. 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 the high pressure region), the force of the spring 9 becomes relatively small, but in the present embodiment, the pressing force of the main valve 11 is the spring 9 The pressure in the pilot chamber 13 as well as the force in (1) can provide a sufficient pressing force, 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 (1) above, there is no inconvenience caused by increasing the force of the spring 9 as in the conventional case. That is, when the pressure of the high pressure chamber 1 to be controlled is particularly low (control in the low pressure region), the force of the spring 9 becomes relatively large, and thus the conventional relief valve is likely to close and malfunction. It was On the other hand, in this embodiment,
Since the main valve 11 receives the pressing force from the pilot chamber 13, when the pressure in the pilot chamber 13 becomes low, this pressing force is immediately lost, the relief valve opens, and the pressure in the high pressure chamber 1 drops to a low predetermined pressure. In this way, the control in the high pressure region and the low pressure region can be sufficiently performed.

[0013]

As described above, according to the relief valve of the present invention, the pilot chamber is provided behind the main valve via the plunger, so that the clearance between the leaf valve and the main valve due to deformation or the like is temporarily provided. However, 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 does not leak and decrease from this gap. Therefore, it is possible to prevent the relief valve from being opened and closed incorrectly due to the gap.

[Brief description of drawings]

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

FIG. 2 is a vertical sectional view showing a conventional example.

[Explanation 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 (solenoid valve) 21 Plunger 23 Coil 25 Solenoid part 27 Central shaft 29 hole 31 hole 33 hole 35 Opening Spacer 37 Plunger 39 Case 41 Support 43 Cap 45 Guide 47 Passage 49 Housing 51 Chamber 53 Orifice Passage 55 Poppet Chamber 57 Communication Portion 59 Passage 60 Solenoid 61 O-ring 63 Casing 65 Valve Guide 67 Kanza

Claims (1)

[Claims] 1. A leaf valve that opens and closes by contacting with and separating from a low pressure chamber side of a valve seat provided on the high pressure chamber side, a main valve that presses from above the leaf valve, and a main valve that is provided behind the main valve via a plunger. A pilot room,
A pilot passage having an orifice communicating with the pilot chamber and the high pressure chamber, a solenoid valve for adjusting the opening between the pilot passage and the low pressure chamber, and a spring for urging the main valve in the pressing direction are provided. Relief valve characterized by that.