JP4987393B2 - Pressure control valve - Google Patents

Description

  The present invention relates to an improvement in a pressure control valve.

  Conventionally, this type of pressure control valve includes, for example, a hollow housing and a spool that is inserted into the housing by sliding the land portions at both ends, and a supply port and a discharge port provided in the housing are provided. A pressure control valve that controls the pressure by restricting the supply port by communicating with a gap between the inner periphery of the housing and the outer periphery between the land portions of the spool so that the outer periphery of the land at one end of the spool faces the supply port. There is. (For example, refer to Patent Document 1).

Specifically, the spool is urged to one side by a spring, and the energized state connects the supply port and the discharge port, or the supply port is closed at the land portion and the supply port and the discharge port are closed. It is set to the normally closed type that cuts off the communication, and the pressure is controlled by adjusting the degree of wrapping (overlapping degree) between the supply port and the land of the spool by applying a thrust to the spool to the spool with a solenoid. It has become.
Japanese Patent Laid-Open No. 11-166641 (FIGS. 1 and 6)

  However, the pressure control valve as described above may be pointed out to have the following problems.

  That is, in the pressure control valve as described above, the pressure is controlled by restricting the supply port at the land portion of the spool and increasing the pressure. Therefore, between the outer periphery between the land portions of the spool and the inner periphery of the housing. There is a problem that the flow rate of the hydraulic oil passing through the gap increases, the flow of the hydraulic oil peels off from the inner wall of the housing, cavitation occurs, and abnormal noise occurs.

  Therefore, the present invention has been developed to improve the above-described problems, and an object of the present invention is to provide a pressure control valve that can prevent the generation of abnormal noise.

In order to solve the above-described object, the problem solving means in the present invention includes a hollow housing and a spool inserted into the housing by sliding the land portions at both ends into the housing, and the supply port provided in the housing And the discharge port communicate with each other via a gap between the inner periphery of the housing and the outer periphery between the land portions of the spool, and the land portion outer periphery of one end of the spool is opposed to the supply port. In the pressure control valve for controlling the pressure by restricting the supply port, a large-diameter portion is provided between the land portions of the spool to narrow a gap with the inner periphery of the housing, and the large-diameter portion is larger than each land portion. It is formed in a small diameter and is provided in the center between the land portions.

  In the pressure control valve according to the present invention, the land portion opens the supply port, and the large-diameter portion provides resistance to the flow of the fluid flowing into the gap between the outer periphery of the spool and the inner periphery of the housing. It functions as a throttle, and the flow velocity of the fluid passing through the gap can be reduced as compared with the conventional pressure control valve, and the pressure loss generated when the fluid passes through the supply port can be reduced.

  Therefore, it is possible to prevent the flow of fluid passing through the gap from being peeled off from the inner wall of the housing, thereby preventing the occurrence of cavitation and eliminating the problem of generating abnormal noise.

  Moreover, since the occurrence of cavitation can be prevented as described above, the occurrence of erosion that erodes the outer periphery of the spool and the inner periphery of the housing can also be prevented.

  Since the flow velocity of the fluid passing through the gap can be reduced, it is possible to reduce the fluid force that acts on the spool to displace the spool from the position positioned with respect to the housing. As a result, controllability is improved and accurate pressure control is possible, and the influence of fluid force can be reduced, so that the springs and solenoids required to drive the spool can be made smaller. Become.

  Furthermore, since only the large-diameter portion that narrows the clearance between the outer periphery of the spool and the land portion between the inner periphery of the housing is provided in this way, the processing is very simple and the workability is good. There is no need to take measures such as adding an orifice for reducing the flow velocity downstream, and there is no fear of forgetting to assemble parts for adding the orifice.

Hereinafter, the pressure control valve of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a pressure control valve according to a reference embodiment in a state where a supply port is opened. FIG. 2 is a longitudinal sectional view in a state where the pressure control valve of the reference form closes the supply port. Figure 3 is a longitudinal sectional view of a definitive pressure control valve in the form status of one embodiment.

As shown in FIG. 1, the pressure control valve 1 in the reference embodiment includes a hollow housing 2, a spool 3 inserted into the housing 2 by sliding the land portions 3 a and 3 b at both ends, and the spool 3 in the housing. 1 is interposed between the housing 2 and the left end of the spool 3 in FIG. 1 so that the spool 3 is located in the right direction in FIG. And the supply port 2a provided on the side of the housing 2 is opposed to the outer peripheral surface of the land portion 3a to narrow the supply port 2a. That is, the opening of the supply port 2a is formed. The fluid pressure on the upstream side of the supply port 2a to be controlled is controlled by partially closing the land portion 3a with the outer peripheral surface to reduce the flow path area.

  Hereinafter, each part will be described in detail. The housing 2 is formed in a bottomed cylindrical shape, and a supply port 2a and a discharge port 2b are provided on the side portion, and a hole 2c is provided on the bottom portion. Yes. Further, the side between the supply port 2a and the discharge port 2b and the side on the opening end side are enlarged in diameter, and annular grooves 2d and 2e are provided on the outer periphery of the enlarged diameter portion. Annular seal members 2f and 2g are mounted in 2d and 2e.

  For example, as shown in FIG. 1, the housing 2 is inserted into a valve hole 11 provided in the block 10, and communicates a pressure source that supplies a fluid (not shown) provided in the block 10 with the valve hole 11. The supply port 2a and the discharge port 2b are opposed to the supply port 2a and the discharge side channel 13 communicating the tank and the valve hole 11 (not shown), respectively, and the supply side channel 12 and the supply port are separated by the sealing member 2f. 2a is sealed between the discharge-side flow path 13 and the discharge port 2b, and further, between the valve hole 11 and the housing 2 is sealed by a seal member 2g.

  Subsequently, the spool 3 is provided with a pair of land portions 3a and 3b slidably in contact with the inner periphery of the housing 2 at both ends, and the diameter between the land portions 3a and 3b is smaller than the outer diameter of the land portions 3a and 3b. A small-diameter portion 3c and a large-diameter portion 3d that is smaller in diameter than the outer diameter of the land portions 3a and 3b but larger than the outer diameter of the small-diameter portion 3c are provided. Further, the small diameter portion 3c is continuous with the land portion 3b, the large diameter portion 3d is continuous with the land portion 3a, and a tapered surface is formed between the small diameter portion 3c and the land portion 3b and between the small diameter portion 3c and the large diameter portion 3d. 5 and 6. In addition, the flow of the fluid becomes smooth by using the tapered surfaces 5 and 6 in this way.

  As shown in FIG. 2, the supply port 2a is closed when the outer periphery of the land portion 3a of the spool 3 completely faces the opening of the supply port 2a, while the supply port 2a is completely closed by the land portion 3a. When the opening of the supply port 2a is allowed to communicate with the housing 2 without being blocked, the supply port 2a and the discharge port 2b are located between the inner periphery of the housing 2 and the small diameter portion 3c and the large diameter portion 3d of the spool 3. The fluid communicated through the gap R and supplied from the supply side flow path 12 is discharged to the discharge side flow path 13 through the gap R.

  Further, the flow passage area, which is the area where the opening of the supply port 2a communicates with the inside of the housing 2, can be adjusted by the degree of overlap between the opening of the supply port 2a and the outer peripheral surface of the land portion 3a. Then, when the fluid flowing through the supply port 2a and flowing into the gap R passes through the supply port 2a, a pressure loss occurs, and the magnitude of the pressure loss depends on the size of the flow path area. Therefore, the pressure in the supply-side channel 12 can be controlled by adjusting the channel area.

  Further, the spool 3 is provided with a hole 3e that opens from the left in FIG. 1 and a hole 3g that opens from the side of the convex portion 3f provided at the right end in FIG. 1 and communicates with the hole 3e. The pressure of the discharge side passage 13 acting on the left end in FIG. 1 of the spool 3 also acts on the right end of the spool 3 in FIG. 1 through the hole 2 c provided in the bottom of the housing 2. The land portions 3 a and 3 b are set to have the same outer diameter so that the pressure receiving areas at both ends of the spool 3 are the same. It will not be displaced.

A spring 4 for biasing the spool 3 toward the right side in FIG. 1 with respect to the housing 2 is interposed between a step 3 h provided in the middle of the hole 3 e of the spool 3 and the bottom of the housing 2. When the solenoid S, which will be described later, is not supplied with current, the spool 3 is arranged at the right end of the housing 2 by the spring 4, and the land portion 3a is in the state of least overlapping the opening of the supply port 2a. Since the maximum opening 2a and the other land portion 3b also open the discharge port 2b, the pressure control valve 1 is in the maximum open state in this state. Therefore, in the case of this reference form, the pressure control valve 1 is a normally open type.

  In turn, a casing 20 of a solenoid S is connected to the right end of the block 10 in FIG. 1. The solenoid S is accommodated in the casing 20 and a plunger 21 movable in the left-right direction in FIG. And a stator (not shown) that sucks the plunger 21.

  Although not illustrated, the stator includes a coil, an iron core that is magnetized by supplying current to the coil and attracts the plunger 21, and a spring that biases the plunger 21 to the right. When a current is supplied to a coil (not shown), the plunger 21 is attracted to the iron core and moves in a direction protruding from the casing 20, and a thrust in the left direction in FIG. The spool 3 can be moved to the left in FIG. 1 against the urging force.

  Then, the spool 3 can be positioned at an arbitrary position within the movable range with respect to the housing 2 by balancing the thrust leftward in FIG. 1 applied to the spool 3 by the solenoid S and the urging force of the spring 4. . That is, in this pressure control valve 1, by controlling the current supplied to the solenoid S, the degree of overlap between the opening of the supply port 2a and the outer peripheral surface of the land portion 3a is adjusted to adjust the channel area, and the supply side The pressure in the flow path 12 can be controlled.

  As described above, the pressure control valve 1 is configured and can control the pressure in the supply-side flow path 12. The housing 2 is disposed between the land portions 3 a and 3 b of the spool 3 of the pressure control valve 1. A large-diameter portion 3d that narrows the gap R between the inner periphery of the spool 3 and the outer periphery of the spool 3 is formed.

In the pressure control valve 1 according to the reference embodiment, the land portion 3a opens the supply port 2a, and the large diameter portion 3d provides resistance against the flow of fluid flowing into the gap R. Functioning, the flow velocity of the fluid passing through the gap R between the outer periphery between the land portions 3a and 3b of the spool 3 and the inner periphery of the housing 2 can be reduced as compared with the conventional pressure control valve. It is possible to reduce the pressure loss that occurs when passing through the supply port 2a.

  Therefore, it is possible to prevent a situation in which the flow of fluid passing through the gap R between the outer periphery between the land portions 3a and 3b of the spool 3 and the inner periphery of the housing 2 is separated from the inner wall of the housing 2, thereby preventing cavitation. Generation | occurrence | production can be blocked | prevented and the malfunction which abnormal noise generate | occur | produces is eliminated.

Further, in the pressure control valve 1 in the reference embodiment, the occurrence of cavitation can be prevented, so that the occurrence of erosion that erodes the outer periphery of the spool 3 and the inner periphery of the housing 2 can also be prevented.

  Since the flow velocity of the fluid passing through the gap R can be reduced, the fluid force that acts on the spool 3 to displace the spool 3 from the position positioned with respect to the housing 2 is reduced. As a result, the controllability is improved, the pressure control can be performed with high accuracy, and the influence of the fluid force can be reduced, so that the spring 4 and the solenoid S can be reduced in size. Become.

  Furthermore, since the large-diameter portion 3d that narrows the gap R between the outer periphery of the spool 3 and the land portions 3a and 3b between the inner periphery of the housing 2 is only provided in this way, the processing becomes very simple. Therefore, it is not necessary to take measures such as adding an orifice for reducing the flow velocity at the discharge port 2b or downstream thereof, and there is no fear of forgetting to assemble parts for adding the orifice.

Subsequently, a description will be given pressure control valve 30 which definitive to form status of one embodiment shown in FIG. The pressure control valve 30 in this embodiment is only different from the spool 3 of the pressure control valve 1 of the reference embodiment described above in the arrangement of the large diameter portion 31e in the land portions 31a and 31b of the spool 31. Accordingly, it described in detail the pressure control valve 1 and the different parts of the reference embodiment, the same members as in Reference Embodiment, since explanation is duplicated, omitting detailed description thereof and only referring to the figures And

As shown in FIG. 3, the spool 31 in the pressure control valve 30 in this embodiment is provided with a pair of land portions 31 a and 31 b slidably in contact with the inner periphery of the housing 2, and between the land portions 31 a and 31 b. The small diameter portions 31c, 31d smaller than the outer diameter of the land portions 31a, 31b and the outer diameter of the small diameter portions 31c, 31d are smaller than the outer diameter of the land portions 31a, 31b between the small diameter portions 31c, 31d. A larger diameter portion 31e having a larger diameter is provided. Further, tapered surfaces 32 and 33 are formed between the small diameter portions 31c and 31d and the large diameter portion 31e, and further, a tapered surface 34 is formed between the small diameter portion 31c and the land portion 31b.

  Even in the spool 31, the supply port 2a is closed when the outer periphery of the land portion 31a of the spool 31 completely faces the opening of the supply port 2a. On the other hand, the supply port 2a is completely closed by the land portion 31a. If the opening of the supply port 2a is allowed to communicate with the housing 2 without blocking, the supply port 2a and the discharge port 2b are connected to the inner periphery of the housing 2, the small diameter portions 31c and 31d and the large diameter portion 31e of the spool 31. The fluid that is communicated via the gap R2 between the two and supplied from the supply side flow path 12 is discharged to the discharge side flow path 13 via the gap R2.

  Further, the flow passage area, which is the area where the opening of the supply port 2a communicates with the inside of the housing 2, can be adjusted by the overlapping degree of the opening of the supply port 2a and the outer peripheral surface of the land portion 31a. Then, when the fluid that passes through the supply port 2a and flows into the gap R2 passes through the supply port 2a, a pressure loss occurs. The magnitude of the pressure loss depends on the size of the flow path area. Therefore, the pressure in the supply-side channel 12 can be controlled by adjusting the channel area.

Further, similar to the spool 3 in the reference embodiment, the spool 31 has a hole 31f that opens from the left in FIG. 3, and a hole 31f that opens from the side of the convex portion 31g provided at the right end in FIG. The pressure of the discharge side flow path 13 acting on the left end of the spool 31 in FIG. 3 through the hole 2c provided at the bottom in the housing 2 is provided at the right end of the spool 31 in FIG. Also comes to work.

  The land portions 31a and 31b are set to have the same outer diameter so that the pressure receiving areas at both ends of the spool 31 are the same. It will not be displaced.

Therefore, this pressure control valve 30 is also of a normally open type, similar to the pressure control valve 1 in the reference embodiment, and by controlling the current supplied to the solenoid S, the opening and land portion of the supply port 2a The pressure in the supply side flow path 12 can be controlled by adjusting the degree of overlap with the outer peripheral surface of 31 a to adjust the flow path area.

  The pressure control valve 30 in the present embodiment also functions as a throttle that the large-diameter portion 31e provides resistance to the flow of fluid that flows into the gap R2 with the land portion 31a opening the supply port 2a. The flow velocity of the fluid passing through the gap R2 between the outer periphery between the land portions 31a and 31b of the spool 31 and the inner periphery of the housing 2 can be reduced as compared with the conventional pressure control valve, and the fluid is supplied to the supply port. It is possible to reduce the pressure loss that occurs when passing through 2a.

  Therefore, it is possible to prevent a situation in which the flow of fluid passing through the gap R2 between the outer periphery between the land portions 31a and 31b of the spool 31 and the inner periphery of the housing 2 is separated from the inner wall of the housing 2, thereby preventing cavitation. Generation | occurrence | production can be blocked | prevented and the malfunction which abnormal noise generate | occur | produces is eliminated.

  Further, in the pressure control valve 30 according to the present embodiment, since the occurrence of cavitation can be prevented, the occurrence of erosion that erodes the outer periphery of the spool 31 and the inner periphery of the housing 2 can also be prevented. .

Further, since the flow velocity of the fluid passing through the gap R2 can be reduced, the fluid force that acts on the spool 31 to displace the spool 31 from the position positioned with respect to the housing 2 is reduced. As a result, the controllability is improved, the pressure control can be performed with high accuracy, and the influence of the fluid force can be reduced, so that the spring 4 and the solenoid S can be reduced in size. Become.

  Furthermore, since only the large-diameter portion 31e that narrows the gap R2 between the outer periphery of the spool 31 and the land portions 31a and 31b and the inner periphery of the housing 2 is provided as described above, the processing becomes very simple. Therefore, it is not necessary to take measures such as adding an orifice for reducing the flow velocity at the discharge port 2b or downstream thereof, and there is no fear of forgetting to assemble parts for adding the orifice.

This concludes the description of the pressure control valves 1 and 30 in one embodiment. As described above, each of the pressure control valves 1 and 30 has the spool 3 and 31 attached by the spring 4 when the solenoid S is not energized. The normal open type that opens the supply port 2a to the maximum is energized. Conversely, when the solenoid S is not energized, the land portions 3a and 31a of the spools 3 and 31 close the supply port 2a. It may be a control valve.

 Also, the scope of the invention is not limited to the details shown or described.

It is a longitudinal cross-sectional view in the state where the pressure control valve of a reference form has opened the supply port. It is a longitudinal cross-sectional view in the state which the pressure control valve of the reference form has obstruct | occluded the supply port. It is a longitudinal sectional view of a definitive pressure control valve in the form status of one embodiment.

Explanation of symbols

1,30 Pressure control valve 2 Housing 2a Supply port 2b Discharge port 2c Hole 2d, 2e Annular groove 2f, 2g Seal member 3, 31 Spool 3a, 3b, 31a, 31b Land portion 3c, 31c, 31d Small diameter portion 3d, 31e Large Diameter 3e, 3g, 31f, 31h Hole 3f, 31g Protrusion 3h Step 4 Spring 5, 6, 32, 33 Tapered surface 10 Block 11 Valve hole 12 Supply side flow path 13 Discharge side flow path 20 Casing 21 Plunger R, R2 Clearance S Solenoid

Claims (1)

A hollow housing and a spool inserted into the housing by sliding the land portions at both ends into the housing, and a supply port and a discharge port provided in the housing include an inner periphery of the housing and the land portion of the spool. A pressure control valve that controls the pressure by restricting the supply port with the outer periphery of the land portion at one end of the spool facing the supply port so that the pressure is controlled by communicating with a gap between the spool and the outer periphery. A large-diameter portion that narrows the gap with the inner periphery of the housing is provided between the land portions, and the large-diameter portion is formed to have a smaller diameter than each of the land portions and provided in the center between the land portions. A pressure control valve characterized by

Images