JPH0522958U - Pressure control valve - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a pressure control valve capable of preventing an increase in hysteresis and the occurrence of a threshold. [Structure] Each spring retainer 41a, 41b is formed of resin and the spring retainer 41a, 41b is formed.
On the other hand, the tip ends of the centering springs 4e and 4f are molded and integrated, and the base ends of the centering springs 4e and 4f are positioned and fixed on the seating surfaces 56a and 56b.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a pressure control valve applied to a vehicle-mounted four-wheel steering system and other industrial equipment, and more particularly to a pressure control valve that controls two output hydraulic pressures.

[0002]

[Prior Art]

 As a conventional pressure control valve, for example, the one described in Japanese Utility Model Laid-Open No. 2-92178 is known.

This conventional pressure control valve slides on the valve body and controls the throttle amount between the hydraulic pressure supply circuit and the first and second output circuits and the drain circuit to control both output circuits. A valve spool capable of controlling the output hydraulic pressure, a first pressing means for sliding the valve spool in the output hydraulic pressure increasing direction of the first output circuit, and an output hydraulic pressure increasing pressure of the second output circuit for the valve spool. A second pressing means that slides in a direction, a centering spring that urges the valve spool to a neutral position where the output hydraulic pressures of the first and second output circuits both decrease, and the valve spool and each centering spring. The spring retainer is interposed between the spring retainer and the spring retainer, which are respectively in contact with the end faces of the valve spool and the valve body at the neutral position of the valve spool.

The spring retainer serves to prevent the biasing force of the centering spring on the side opposite to the sliding direction from acting on the valve spool when the valve spool slides to one side. The structure was such that each spring retainer was positioned by slidably attaching it to the outer circumference of the end of the valve spool.

[0005]

[Problems to be solved by the device]

 However, such a conventional pressure control valve has a structure in which the spring retainer is slidably attached to the outer circumference of the end portion of the valve spool as a means for determining the position of the spring retainer. was there.

That is, when the valve spool slides in one direction, the spline retainer on the side opposite to the sliding direction comes into contact with the end surface of the valve spool and the sliding is stopped. A frictional force is generated on the sliding surface between the inner circumference of the spring retainer whose sliding is stopped and the outer circumference of the end of the valve spool on which the spring retainer is slidably mounted, and the reaction force of the centering spring causes the reaction force of the spring. Since it acts as a lateral force on the valve spool via the retainer, the frictional force at the sliding surface between the valve body and the valve spool increases, which increases the hysteresis and easily causes the threshold.

The present invention was made in view of the above-mentioned conventional problems, and an object thereof is to provide a pressure control valve capable of preventing an increase in hysteresis and the occurrence of a threshold.

[0008]

[Means for Solving the Problems]

 In the present invention, both spring retainers are formed of resin, and the tip ends of the centering springs are molded and integrated with the spring retainers, and the base ends of the centering springs are positioned and fixed on their seating surfaces. Therefore, it was decided to achieve the above objective.

That is, in the pressure control valve of the present invention, it slides with respect to the valve body and controls the throttle amount between the hydraulic pressure supply circuit and the first / second output circuit and the drain circuit to control both outputs. A valve spool capable of controlling the output fluid pressure of the circuit, a first pressing means for sliding the valve spool in the direction of increasing the output fluid pressure of the first output circuit, and a valve spool for the output fluid of the second output circuit. Second pressing means for sliding in the pressure increasing direction, a pair of centering springs for urging the valve spool to a neutral position where the output hydraulic pressures of the first and second output circuits both decrease, and the valve spool A spring retainer is provided between the centering spring and the centering spring, and the spring retainer contacts the end faces of the valve spool and the valve body at the neutral position of the valve spool. The center is formed of resin, and the tip end side of each centering spring is molded and integrated with the spring retainer, and the base end side of each centering spring is positioned and fixed on its seating surface side.

[0010]

[Action]

 In the pressure control valve of the present invention, normally, the valve spool is held in the neutral position by the urging force of the centering spring, and the high-pressure working liquid introduced from the hydraulic pressure supply circuit is recirculated through the drain circuit. As a result, the output hydraulic pressures of both output circuits are in the same pressure (low pressure) state.

Next, when the first pressing means is operated, the valve spool slides in the first output hydraulic pressure increasing direction to open the throttle opening between the hydraulic pressure supply circuit and the first output circuit. As a result, the output hydraulic pressure of the first output circuit rises.

Next, when the second pressing means is operated, the valve spool slides in the second output hydraulic pressure increasing direction to open the throttle opening between the hydraulic pressure supply circuit and the second output circuit. As a result, the output hydraulic pressure of the second output circuit rises.

As described above, when the valve spool slides, the spring retainer on the sliding direction side moves together with the valve spool, and the spring retainer on the opposite side to the sliding direction moves on the valve body. The spring retainer on the sliding direction side moves relative to the valve body because it abuts against the end face and its movement is blocked, and the valve spool moves relative to the spring retainer on the opposite side to the sliding direction. However, since each spring retainer is integrated with the centering spring, and the centering spring is positioned on the seating surface side at the base end side, each spring retainer serves as the relative moving part. It does not need to be supported by the body or valve spool.

Therefore, a sufficient gap can be formed between the relative moving parts to prevent an increase in hysteresis and the occurrence of a threshold.

In addition, the centering springs are integrated by previously molding the tip ends of the centering springs into the resin material forming the spring retainers.

Therefore, compared to the case where the tip end side of the centering spring is fitted to the spring retainer, it is not necessary to consider the dimensional tolerance of the fitting portion, so that the cost can be reduced and the spring retainer can be made of resin. Since the centering spring is bent less due to the weight of the spring retainer, the gap formed between the relative moving portion and the spring retainer can be set smaller. Therefore, the degree of freedom in design is high.

[0017]

【Example】

 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

First, the configuration of the embodiment will be described.

FIG. 1 is a cross-sectional view showing a pressure control valve according to an embodiment of the present invention. The pressure control valve controls the output hydraulic pressures P ₁ and P ₂ of the first output circuit S1 and the second output circuit S2. It is the one that controls. Such hydraulic control of the output hydraulic pressures P ₁ and P ₂ of the two output circuits S1 and S2 is used, for example, in the operation of the steering angle control device for the rear wheels. In such a steering angle control device, For example, an increase in the output hydraulic pressure of the first output circuit S1 steers the rear wheels to the right, and an increase in the output hydraulic pressure of the second output circuit S2 steers the rear wheels to the left. It is made.

In the figure, reference numeral 1 is a valve body, and a valve hole 11 is formed in the valve body 1. A first output port 11a and a second output port 11b are formed in the valve hole 11, a hydraulic pressure supply circuit 2 is connected between the ports 11a and 11b, and both ports 11a and 11b are connected. The drain circuit 3 is connected to the outer position. Further, a first back chamber 1a and a second back chamber 1b having a diameter larger than that of the valve hole 11 are formed at both ends of the valve hole 11.

The first output port 11a is connected to the first output circuit S1, while the second output port 11b is connected to the second output circuit S2. Further, the hydraulic pressure from the pump P is supplied to the hydraulic pressure supply circuit 2. Further, the drain circuit 3 is connected to the reservoir tank T via the filter F and is at atmospheric pressure. Further, the drain circuit 3 is connected to the first back chamber 1a and the second back chamber 1b via drain side communication passages 100a and 100b.

A valve spool 4 is slidably incorporated in the valve hole 11. Further, the valve spool 4 has a first land 4a which is provided in the first output port 11a in an underlapped state to form throttles q and r between the valve hole 11 and the second output port 11b. A second land 4b which is provided in a lapped state and forms throttles s and t with the valve hole 11 and end lands 4c and 4d at both ends are formed. The opening degree is adjusted to control the supply amount of the hydraulic pressure introduced from the hydraulic pressure supply circuit 2 to both output circuits S1 and S2 and the drain amount to the drain circuit 3.

That is, when the valve spool 4 slides to the right in the drawing, the drain-side throttle r is narrowed and the hydraulic pressure supply-side throttle q is widened in the first output port 11a, so that the first output circuit S1 is opened. If the output fluid pressure P ₁ to the valve rises and the valve spool 4 slides to the left in the figure, on the other hand, the throttle t narrows and the throttle s widens, and the output fluid of the second output circuit S2 The pressure P ₂ rises.

Both ends of the valve spool 4 are elastically supported by centering springs 4e and 4f, and the valve spool 4 is slidably biased so that both output hydraulic pressures P ₁ and P ₂ are arranged in a neutral position where they become drain pressures. ing.

Further, spring retainers 41 a and 41 b are interposed between the centering springs 4 e and 4 f and the valve spool 4. The spring retainers 41a and 41b are provided so as to form outer annular gaps 12a and 12b and inner annular gaps 13a and 13b between the valve body 1 and the outer peripheral surface of the end of the valve spool 4, respectively. When the end face is in contact with the outer end faces of the valve body 1 and the outer end faces of the respective end lands 4c, 4d at the neutral position of the valve spool 4 at the same time, the valve spool 4 is in the neutral position. The elastic force is prevented from being transmitted to the valve spool 4 when sliding in the direction away from the centering springs 4e and 4f.

Further, the spring retainers 41a and 41b are made of resin, and when the spring retainers 41a and 41b are molded, the tips of the centering springs 4e and 4f are molded on the outer end surfaces thereof so that they are integrally molded. ing.

The valve spool 4 slides by means of first and second solenoids 5a and 5b. That is, the valve body 1 at both ends of the valve hole 11 is provided with the first solenoid 5a and the second solenoid 5b, respectively. When both solenoids 5a and 5b are energized, the plunger 51a is generated by the generated suction force. , 51b slides to press the valve spool 4, and when the first solenoid 5a is energized, the valve spool 4 is slid to the right in the figure and the output hydraulic pressure P ₁ of the first output circuit S1 is increased. On the contrary, when the second solenoid 5b is energized, the output hydraulic pressure P ₂ of the second output circuit S2 is increased.

The slide of the plungers 51a and 51b is restricted by the respective stopper surfaces 52a, 53a, 52b and 53b in the solenoids 5a and 5b. The plungers 51a and 51b are applied with preset loads to the valve spool 4 by solenoid springs 54a and 54b, respectively.

A first piston sliding hole 63a and a second piston sliding hole 63b are bored in both ends of the valve spool 4 in the axial direction, and the piston sliding holes 63a, 63b are A first reaction force piston 64a and a second reaction force piston 64b, each of which is rounded at both ends, are slidably inserted.

The piston sliding holes 63a and 63b are respectively connected to the first output port 11a by the first feedback hydraulic pressure introducing hole 61a and the second feedback hydraulic pressure introducing hole 61b formed in the valve spool 4. The two reaction force pistons 64a, 64b, which are communicated with the second output port 11b, have pressure receiving surfaces 65a, 65b on one end surface side for receiving the feedback hydraulic pressure.

Further, stopper members 7a and 7b are interposed between the reaction force pistons 64a and 64b and the plungers 51a and 51b of the solenoids 5a and 5b. As shown in the drawing, the stopper members 7a and 7b have a cylindrical shape having bottom portions 71a and 71b. It is formed so as to be able to contact both of the tips, whereby the pressing force of the plungers 51a, 51b can be transmitted to the valve spool 4 and the reaction force pistons 64a, 64b. The inner surfaces 73a and 73b of the bottoms 71a and 71b of the stopper members 7a and 7b are arranged in contact with the plungers 51a and 51b.

Further, the end surfaces of the stopper members 7a, 7b on the side opposite to the bottom portions 71a, 71b are stopper surfaces 74a, 74b, which are spring seating surfaces formed on the casings 55a, 55b of the solenoids 5a, 5b. It is formed so as to be able to contact with 56a and 56b.

That is, the stopper members 7a, 7b and the spring seating surfaces 56a, 56b constitute stopper means for restricting the sliding of the reaction force pistons 64a, 64b by the feedback hydraulic pressure.

Further, around the spring seating surfaces 56a, 56b of the casings 55a, 55b, there are formed cylindrical protrusions 57a, 57b fitted in the respective back chambers 1a, 1b. The base ends of the centering springs 4e and 4f are fitted on the inner peripheral sides of the cylindrical protrusions 57a and 57b, whereby the centering springs 4e and 4f and the spring retainers 41a and 41b are fitted in the valve hole 11. On the other hand, the positioning is performed so as to form concentric circles.

Next, the operation of the embodiment will be described.

(A) At neutral time Normally, the valve spool 4 is held at the neutral position by the urging force of the centering springs 4e and 4f, and the high pressure hydraulic fluid introduced from the hydraulic pressure supply circuit 2 is introduced into the hydraulic pressure. After passing through the side throttles q and s, the drain side throttles r and t return to the reservoir tank T through the drain circuit 3.

As a result, the output hydraulic pressures of both output circuits S ₁ and S ₂ are in the same pressure (low pressure) state.

(B) When driving the first solenoid 5a When the first solenoid 5a is energized, a suction force is generated, and this suction force causes the plunger 51a and the stopper member 7b to move integrally in the direction of the valve spool 4. . Then, the bottom outer surface 72b of the stopper member 7b comes into contact with the left end surface of the valve spool 4, and pushes the valve spool 4 in the right direction in the figure to slide it.

By the sliding of the valve spool 4, the throttle r is narrowed and the throttle q is expanded, and the output hydraulic pressure P _{1 of} the first output port 11a and the first output circuit S1 is increased.

Further, the hydraulic pressure of the first output port 11a is transmitted to the first piston sliding hole 63a, and the feedback hydraulic pressure is received by the pressure receiving surface 65a. It is pressed in the middle right direction. When the first reaction force piston 64a comes into contact with the stopper member 7a and the sliding in the right direction in the drawing is restricted, the reaction force of the feedback hydraulic pressure acts on the valve spool 4 as a feedback force, The spool 4 is pushed back to the left in the figure.

Then, when the valve spool 4 is arranged at a position where this feedback force and the pressing force of the first solenoid 5a are balanced, the output hydraulic pressure P ₁ of the first output circuit S1 is transferred to the first solenoid 5a. The hydraulic pressure is controlled to be proportional to the value of the electric current that flows. Further, as described above, when the valve spool 4 slides to the right in the drawing (and is pushed back to the left in the drawing), the inner surface of the left spring retainer 41b is the valve body. Since the valve spool 4 is moved relative to the spring retainer 41b because it abuts against the end surface of No. 1 and its movement is blocked, the space between the spring retainer 41b and the outer peripheral surface of the end portion of the valve spool 4 is increased. Since the inner annular gap 13b is formed in the inner side, frictional force is not generated between them. On the other hand, the spring retainer 41a on the right side slides together with the valve spool 4, so that the spring retainer 41a moves relative to the valve body 1, but between the valve body 1 and the spring retainer 41a. Since the outer annular gap 12a is formed, no frictional force is generated between the two.

(C) When the second solenoid 5b is driven When the second solenoid 5b is energized, the output hydraulic pressure P ₂ of the second output circuit S2 is increased, contrary to the driving of the first solenoid 5a. Since the operation is symmetrical with the above case, the description is omitted.

As described above, in this embodiment, the tip ends of the centering springs 4e and 4f are molded at the time of resin molding of the spring retainers 41a and 41b, so that both are completely integrated and The center end springs 4e and 4f are fitted at their proximal ends into the cylindrical protrusions 57a and 57b on the spring seating surfaces 56a and 56b side to be positioned and fixed, whereby the outer annular gaps 12a and 12b are fixed. It is possible to maintain the inner and inner annular gaps 3a and 13b, which can prevent an increase in hysteresis due to the friction of the relative moving parts, and at the same time, to the valve spool 4 due to the reaction force of the centering springs 4e and 4f. Since the action of lateral force can be avoided, it is possible to prevent the occurrence of threshold. Have

Further, since the centering springs 4e and 4f are integrally formed by previously molding the tip ends of the centering springs into the resin material forming the spring retainers 41a and 41b, the centering springs 4e and 4f are centered with respect to the spring retainers 41a and 41b. Compared to the case where the tip ends of the springs 4e and 4f are fitted, it is not necessary to consider the dimensional tolerance of the fitting portion, and therefore, the feature is that the cost can be reduced.

Further, since the spring retainers 41a and 41b are formed of resin, the amount of bending of the centering springs 4e and 4f due to the weight of the spring retainers 41a and 41b can be reduced, so that the outer annular gaps 12a and 12b and The annular gaps 3a and 13b can be set to be small, which has the feature of increasing the degree of freedom in design.

Although the embodiment of the present invention has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and the present invention can be made even if there is a design change or the like within a range not departing from the gist of the present invention. Included in the device.

For example, in the embodiment, the solenoid is used as the pressing means, but other means such as a means for pressing with a hydraulic pressure or a means for pressing with an actuator such as a motor can be applied.

[0048]

[Effect of the device]

 As described above, in the pressure control valve of the present invention, both spring retainers are made of resin, and the tip ends of the centering springs are molded and integrated with the spring retainers, and Since the base end of each centering spring is positioned and fixed on its seating surface side, each spring retainer is supported by the valve body or valve spool that moves relative to each spring retainer for positioning. Since it is not necessary to make it possible, it is possible to form a sufficient gap between the relative moving parts and to prevent an increase in hysteresis due to the friction of the relative moving parts. Since the action of lateral force on the spool can be avoided, the occurrence of thresholds can be prevented. Effect is obtained that it becomes way.

Further, since the tip ends of the centering springs are molded in advance in the resin material forming the spring retainers to be integrated, when the tip ends of the centering springs are fitted to the spring retainers. Compared with this, it is not necessary to consider the dimensional tolerance of the fitting portion, and the cost can be reduced.

Further, since the spring retainer is made of resin, the amount of bending of the centering spring due to the weight of the spring retainer can be reduced, so that the gap formed between the moving parts relative to the spring retainer can be reduced. It can be set, which increases the design flexibility.

[Brief description of drawings]

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

[Explanation of symbols]

1 Valve Body 2 Hydraulic Pressure Supply Circuit 3 Drain Circuit 4 Valve Spool 4e Centering Spring 4f Centering Spring 5a First Solenoid (First Pressing Means) 5b Second Solenoid (Second Pressing Means) 41a Spring Retainer 41b Spring Retainer 56a Spring Seating Surface 56b Spring seating surface P ₁ 1st output hydraulic pressure P ₂ 2nd output hydraulic pressure S1 1st output circuit S2 2nd output circuit

Claims (1)

[Scope of utility model registration request] 1. The output hydraulic pressure of both output circuits can be controlled by sliding on the valve body and controlling the throttle amount between the hydraulic pressure supply circuit and the first and second output circuits and the drain circuit. A valve spool, a first pressing means for sliding the valve spool in the output hydraulic pressure increasing direction of the first output circuit, and a first pressing means for sliding the valve spool in the output hydraulic pressure increasing direction of the second output circuit. 2 pressing means, a pair of centering springs for urging the valve spool to a neutral position where the output hydraulic pressures of the first and second output circuits both decrease, and interposed between the valve spool and both centering springs. And a spring retainer that abuts against the end faces of the valve spool and the valve body at the neutral position of the valve spool, respectively. The leading ends of the centering springs and integrated with the mold to Nguritena, the pressure control valve, characterized in that said positioned and fixed to the base end side of the centering spring at its seating surface side.