JPH0631257Y2 - Pressure control valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a pressure control valve suitable for use in, for example, vehicle attitude control, and more particularly to an electromagnetic proportional pressure control for controlling pressure in proportion to current. Regarding control valve.

(Prior Art) Recently, there is a tendency that automobiles are required to have a high level of comfort. For example, vehicle height adjustments, vehicle body attitude control such as cornering and braking, and the like are performed. Such various controls are often performed using hydraulic pressure, and in this case, a pressure control valve for generating hydraulic pressure proportional to the current value of the solenoid is used.

A conventional pressure control valve of this type is, for example, the actual open sho 62.
There is one described in Japanese Patent Publication No. 2008874/1990, which is shown as in FIG.

In the figure, reference numeral 1 is a pressure control valve, and pressure oil pressurized by a pump or the like (not shown) is supplied to the pressure control valve 1. The pressure oil supplied to the pressure control valve 1 is guided by an oil passage 3 that opens around the spool valve 2, and the spool valve 2 receives the electromagnetic force of a solenoid 4 at one end and slides in the direction of arrow A in the figure. Then, the pressure oil guided by the oil passage 3 is guided to the control chamber 5 formed in the central portion of the spool valve 2 and supplies the pressure oil to a load (not shown) via the oil passage 6. When the pressure in the control chamber 5 rises, the pressure is guided via the oil passage 7 to the feedback chamber 8 defined at the other end of the spool valve 2. The feedback chamber 8 is defined by a groove portion 9 formed at the other end of the spool valve 2, and a tip portion 10 of the spool valve 2 is a sliding portion of the spool valve 2 with the groove portion 9 as a boundary.
The diameter is smaller than 11. At this time, the control pressure guided to the feedback chamber 8 acts on the pressure receiving area based on the difference in diameter between the tip portion 10 and the sliding portion 11, and acts on the spool valve 2 in opposition to the electromagnetic force of the solenoid 4. . Therefore, the feedback pressure in the feedback chamber 8 increases as the control pressure increases, and the spool valve 2 is pressed in the direction of arrow B in the figure. When the electromagnetic force of the solenoid 4 and the pressing force of the spool valve 2 based on the feedback pressure match, the spool valve 2 closes the oil passage 3 and holds the control pressure at a value according to the electromagnetic force of the solenoid 4.

On the other hand, when the electromagnetic force of the solenoid 4 is reduced, the balance of the spool valve 2 is lost and the spool valve 2 moves in the direction of the arrow B in the figure, and the pressure oil in the control chamber 5 is released to the reservoir tank (not shown) via the oil passage 12. It Therefore, the control pressure is reduced, and at the same time the feedback pressure is reduced.
Slides in the direction of arrow A in the figure, and when the electromagnetic force of the solenoid 4 and the pressing force of the spool valve 2 based on the feedback pressure match, both the oil passage 3 and the oil passage 12 are closed and the control pressure is reduced to the electromagnetic force. Maintain the value according to the value.

In this way, the spool valve 2 is balanced by the pressing force based on the electromagnetic force of the solenoid 4 and the feedback pressure. By setting the pressure receiving area of the feedback chamber 8 small, a large electromagnetic force can be controlled with a small electromagnetic force. Is intended.

However, in such a conventional pressure control valve, since the feedback chamber 8 is defined by the groove portion 9, the following problems occur. That is, although the feedback force can be reduced by forming the pressure receiving area of the feedback pressure in an annular shape by the groove portion 9 and reducing it as much as possible, there is a problem that the feedback force greatly varies due to pressure fluctuation. there were.

Therefore, in order to solve such a problem, a so-called pilot type pressure control valve including two spool valves has been conventionally proposed as a pressure control valve that generates a high control pressure. This pilot type pressure control valve generates pilot pressure by the pilot spool that constitutes one of the two spool valves, presses the main spool that constitutes the other spool valve, and in response to this pressing force, the main spool Allows spool to generate control pressure. In this case, by applying electromagnetic force to the pilot spools and providing a feedback structure on each spool, it is possible to generate a large control pressure with a small electromagnetic force.

(Problems to be solved by the invention) However, in such a conventional pressure control valve, since the pilot spool and the main spool are arranged in parallel, the pilot pressure generated in the pilot spool is not There is no choice but to form a flow path (oil path) in the valve body for transmission to the spool side,
For this reason, the flow path of the valve body becomes complicated, and machining of the valve body is troublesome. Further, a structure is required in which the main spool and the pilot spool are separated from each other and an oil passage for guiding the pilot pressure is provided between them, which leads to an increase in size.

(Purpose of the Invention) Therefore, the present invention has a structure in which the pilot pressure generated by the pilot spool is directly applied to the main spool without passing through the oil passage of the valve body, and the oil passage of the valve body is simplified and the valve body It is an object of the present invention to provide a pressure control valve that simplifies processing and has a simplified valve body structure.

(Means for Solving the Problem) For the above-mentioned purpose, the pressure control valve according to the present invention includes a main spool (23) and a pilot spool (23) in a pair of accommodation holes (60, 61) formed in a valve body (24), respectively. 22) and slides the pilot spool in proportion to the current of the solenoid (25) to move the pilot control chamber (3
In the pressure control valve for controlling the output hydraulic pressure by controlling the pilot pressure in 4), introducing the pilot pressure into the pressure chamber (32) of the accommodation hole of the main spool, and sliding the main spool. A hole is formed substantially coaxially to form a small diameter through hole (62) between the pilot spool accommodating hole and the pressure chamber. A small diameter portion (30) facing the chamber is provided so as to project from one end of the pilot spool, and an oil passage (35) is formed at one end of the pilot spool, one end of which is open and the other end of which is open to the pilot control chamber.

(Operation) In the present invention, the pilot valve hole and the main valve hole are arranged coaxially, and the pilot spool is provided with a small diameter portion so as to protrude into the main valve hole, and the pilot liquid is provided through the communication provided in the small diameter portion. Pressure is applied to the main spool. Therefore, the pilot pressure generated by the pilot spool presses the main spool in the direction in which the control pressure increases, and the pilot spool in the direction facing the urging side of the solenoid.
Since the pilot pressure is controlled to a predetermined pressure, the structure is simple and the size in the axial direction is the minimum necessary, and the size can be reduced.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of a pressure control valve according to the present invention.

First, the configuration will be described. In the figure, 21 is a pilot type pressure control valve, and the pressure control valve 21 has a pilot spool 22 and a main spool 23 which are coaxially arranged. The pilot spool 22 and the main spool 23 are slidably accommodated in the accommodation hole 60 of the pilot spool 22 and the accommodation hole 61 of the main spool 23 in the body 24 of the pressure control valve 21, and both accommodation holes 60, 61 are It is formed coaxially. A solenoid 25 (control means) is fixed to the end of the body 24. The solenoid 25 has a plunger 26 that generates an urging force in the direction of arrow A in the figure by an electromagnetic force, and the tip of the plunger 26 abuts on one end surface of the pilot spool 22. One end surface of the pilot spool 22 faces a low pressure chamber 27 defined on the solenoid 25 side of the pilot spool 22, the low pressure chamber 27 is filled with pressure oil, and the pilot spool 22 is moved in the direction of arrow A in the figure. Biasing spring
28 is inserted. At the other end of the pilot spool 22, a small diameter portion 30 having a cross-sectional area A _{1 having} a smaller diameter than the sliding portion 29 of the pilot spool 22 is formed. The small diameter portion 30 is defined by the pilot spool 22 and is a low pressure chamber. It penetrates through 31 and projects into a pressure chamber 32 which is partially defined by one end surface of the main spool 23 having a cross-sectional area A ₂ . Therefore, the small diameter portion 30 is slidably fitted in the small diameter through hole 62 formed in the body 24 between the accommodation hole 60 and the pressure chamber 32. Low pressure chamber 31
Is filled with pressure oil, and a spring 33 is inserted.The spring 33 connects the pilot spool 22 to a solenoid.
Energize to the 25 side. That is, the pilot spool 22 receives the urging forces of the spring 28 and the spring 33 on both end surfaces, and when the solenoid 25 is not energized, it is stationary at a position where the urging forces are balanced. Pilot spool
A pilot control room 34 is defined in the center of 22.
The pilot control chamber 34 communicates with the pressure chamber 32 via an oil passage 35 (passage) formed in the pilot spool 22. Therefore, the oil passage 35 has one end opened to the tip of the small diameter portion 30 and the other end opened to the pilot control chamber 34. The pressure in the pressure chamber 32 is a pilot pressure, and a pilot pressure is applied to the small diameter portion 30 of the pilot spool 22 to provide a feedback structure that pushes back the pilot spool 22 according to the pilot pressure. A pilot supply port 36 and a pilot drain port 37 are opened around the pilot spool 22, and when the pilot spool 22 is stationary due to the urging force of the springs 28 and 33, the pilot spool 22 has the pilot supply port 36. And the pilot drain port 37 is completely closed (hereinafter referred to as settling). That is, the pilot spool 22 during settling completely separates the pilot supply port 36, the pilot drain port 37, and the pilot control chamber 34. The drain port 37 and the pilot control room 34 communicate with each other.

On the other hand, a spring 38 is inserted in the pressure chamber 32 facing one end surface of the main spool 23, and the spring 38 is the main spool.
23 is urged in the direction of arrow A in the figure. At the other end of the main spool 23, a small piston 39 having a cross-sectional area A ₃ is provided.
Is embedded slidably in the axial direction, the small piston 39 defines a feedback chamber 40 in the main spool 23, and
It comes into contact with the balls 42 of the end cap 41 fixed to the body 24. The end cap 41 defines a low pressure chamber 43 in which a part of the small piston 39 projects together with the main spool 23, and a spring 44 that biases the main spool 23 toward the solenoid 25 is inserted in the low pressure chamber 43. That is, the main spool
The spring 23 receives the biasing forces of the spring 38 and the spring 44 on both end faces thereof, and stands still at a position where the biasing forces are balanced. A control chamber 45 is defined in the center of the main spool 23, and the control chamber 45 is an oil passage formed inside the main spool 23.
It communicates with the feedback room 40 via 46. An oil passage 47 having one end opened on the surface of the body 24 opens in the control chamber 45, and the oil passage 47 guides the control pressure to a load such as a cylinder (not shown). Main supply port around main spool 23
48 and the main drain port 49 are open, and when the main spool 23 is stationary under the urging force of the springs 28 and 44, the main spool 23 completely closes the main supply port 48 and the main drain port 49 ( Hereinafter referred to as settling). That is, the main spool 23 at the time of settling has the main supply port 48, the main drain port 49 and the control room 45.
Are completely independent, and the main supply port 48 and the control chamber 45 or the main drain port 49 and the control chamber 45 communicate with each other according to the sliding movement of the main spool 23. Main supply port 48
An oil passage 50, one end of which is opened on the surface of the body 24, is opened at the end of the body 24. Body 24 in oil passage 50
The oil passage 51 opening to the solenoid 25 side is opened orthogonally, and the oil passage 51 intersects with the oil passage 52 having one end opened to the pilot supply port 36 and the other end opened to the surface of the body 24. . Further, the main drain port 49 has an oil passage 53 whose one end opens to the surface of the body 24, and the oil passage 53 guides the pressure oil to a reservoir tank (not shown). The oil passage 53 is formed so as to penetrate the main drain port 49, and intersects with the oil passage 54 formed in the arrangement direction of the pilot spool 22 and the main spool 23. One end of the oil passage 54 is opened to the end cap 41 side of the body 24, and the oil passage 54 is opened to the low pressure chamber 43, the oil passage 56 to the low pressure chamber 31, and the pilot drain port 37. The oil passage 57 that crosses. An oil passage 58 that opens to the low pressure chamber 27 joins the oil passage 57, and one end of each of the oil passages 55, 56, and 57 opens to the surface of the body 24. In addition, a blind plug is provided at the opening of the body 24 surface of each oil passage 51, 52, 54-57.
60a to 60f are press-fitted to seal each opening.

Next, the operation will be described.

When passing a predetermined current to the solenoid 25, the solenoid 25 electromagnetic force F _S is produced in response to said current feedback control chamber plunger 26 presses the pilot spool 22 34
And the pilot supply port 36 communicate with each other. Therefore, the pressurized pressure oil is guided to the pilot control chamber 34 through the oil passages 50, 51, 52, and the pressures of the feedback control chamber 34 and the pressure chamber 32 communicating with the feedback control chamber 34 both rise. At this time, a force in the direction of arrow A in the figure acts on the main spool 23 as the pressure in the pressure chamber 32 (hereinafter referred to as pilot pressure Pp) rises, and the main spool 23 slides in the direction of arrow A in the figure. . Therefore, the main supply port 48 and the control chamber 45 communicate with each other, and the pressurized pressure oil is supplied to the load as the control pressure Pc. Further, since the pressure oil in the control chamber 45 is guided to the feedback chamber 40 via the oil passage 46, the pressure in the feedback chamber 40 (hereinafter referred to as the feedback pressure P _F ) also rises. When the pilot pressure Pp rises, the pilot pressure Pp and the small diameter portion 30 are stored in the pilot spool 22.
The balance force F _B1 determined by the product of the cross-sectional area A ₁ of
It acts against the electromagnetic force F _{S of} 25 and causes the pilot spool 22
Is pressed to the solenoid 25 side. When the following equation is established, the pilot spool 22 is settled, and the pilot pressure Pp is maintained at a predetermined value according to the electromagnetic force F _S.

Fs = Pp × A ₁ = F _B1 ...... At this time, the feedback pressure P is applied to the main spool 23.
Balance F determined by the product of _F and the cross-sectional area A ₃ of the small piston 39
_B3 acts in the direction of pressing the pilot spool 22 toward the solenoid 25 side, and when the following equation is established, the main spool 23 is settled.

Pp × A ₂ = P _F × A ₃ Here, the feedback pressure P _F is derived from the control pressure Pc, and therefore the above formula can be expressed by the following formula.

Pp × A ₂ = Pc × A ₃ Therefore, the following equation is obtained from the above equation.

That is, by setting the area A ₂ smaller than the area A ₃ and decreasing the area A ₁ , a large control pressure Pc can be operated with a small electromagnetic force Fs.

In this case, the pilot pressure Pp acts on the main spool 23 and also acts as a feedback pressure on the pilot spool 22, and the pilot spool 22 and the main spool 23 are arranged on the same axis with the pressure chamber 32 interposed therebetween. By providing the pilot spool, the pilot pressure Pp operated by the pilot spool 22 can be directly applied to the main spool 23 without passing through a special oil passage or the like.
Therefore, the structure of the pressure control valve 21 for controlling high pressure can be simplified. Further, since it is not necessary to dispose the pilot spool 22 and the main spool 23 separately from each other, the axial dimension of the pressure control valve 21 can be minimized, and the pressure control valve 21 can be downsized. be able to.

On the other hand, if the current of the solenoid 25 is decreased, the electromagnetic force Fs
Is decreased, and the balance force F _B1 in the above equation is the electromagnetic force F
It becomes larger than s and the pilot spool 22 slides toward the solenoid 25 side. At this time, the pressure oil in the pilot control chamber 34 flows from the pilot drain port 37 to the oil passage 57 and the oil passage 53.
Since the pressure in the feedback control chamber 34 decreases as it is opened to the reservoir tank via the pilot pressure P
p also decreases. Therefore, the settling condition of the main spool 23, that is, the relationship of the above equation is broken, the pressure oil of the control chamber 45,
That is, the control pressure Pc is from the main drain port 49 to the oil passage.
It is opened to the reservoir tank via 53. When the above formula is satisfied for the reduced electromagnetic force Fs ', the pilot spool 22 is settled and the pilot pressure Pp is reduced to a value corresponding to the electromagnetic force Fs'. Therefore, the control pressure Pc is reduced to a value according to the pilot pressure.

(Effect) According to the present invention, a pair of accommodation holes formed in the valve body are formed substantially coaxially to form a small-diameter through hole between the accommodation hole of the pilot spool and the pressure chamber. A small diameter portion slidably fitted to the pilot spool so that the tip thereof faces the pressure chamber, is projected from one end of the pilot spool, one end of which is opened at the tip of the small diameter portion and the other end of which is opened to the pilot control chamber. Since the oil passage is formed, in the conventional pilot type pressure control valve, the pilot spool and the main spool are arranged in parallel, while the pilot spool and the main spool are housed in a pair of housing holes formed coaxially. The oil passage for transmitting the pilot pressure generated in the pilot spool to the main spool side is formed in the pilot spool. The ilot pressure can be directly applied to the main spool without passing through the oil passage of the body, which simplifies the oil passage of the valve body and simplifies the processing of the valve body, thereby simplifying the valve body structure. Further, by forming the oil passage for transmitting the pilot pressure generated in the pilot spool to the main spool side in the pilot spool, the overall structure of the pressure control valve can be downsized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a pressure control valve according to the present invention, and FIG. 2 is a sectional view showing a conventional pressure control valve. 21 …… Pressure control valve, 22 …… Pilot spool, 23 …… Main spool, 24 …… Valve body, 25 …… Solenoid (pressing means), 30 …… Small diameter part, 32 …… Pressure chamber, 35 …… Oil Road, 40 ... Feedback chamber, 60 ... accommodation hole, 61 ... accommodation hole, 62 ... through hole.

Claims (1)

[Scope of utility model registration request] 1. A main spool (23) and a pilot spool (22) are respectively housed in a pair of housing holes (60, 61) formed in a valve body (24), and the pilot spool is proportional to a current of a solenoid (25). To control the pilot pressure in the pilot control chamber (34), introduce the pilot pressure into the pressure chamber (32) in the accommodation hole of the main spool, and slide the main spool to control the output hydraulic pressure. In the pressure control valve, the pair of accommodating holes are formed substantially coaxially to form a small-diameter through hole (62) between the accommodating hole of the pilot spool and the pressure chamber, while being slidable in the through hole. A small diameter portion (30) fitted to the pressure chamber and having a tip facing the pressure chamber is projected from one end of the pilot spool, one end of which is open at the tip of the small diameter portion and the other end of which is the pilot control chamber. The pressure control valve, characterized in that the formation of the oil passage mouth (35)