JP4476765B2 - Flow control valve - Google Patents

Description

  The present invention relates to a flow rate control valve that maintains predetermined control characteristics without being affected by changes in pump discharge pressure.

  As this type of flow control valve, the one described in Patent Document 1 has been conventionally known. FIG. 3 shows this conventional flow control valve. As apparent from FIG. 3, the flow rate control valve incorporates a spool 2 in a slidable manner in the valve body 1, and incorporates a valve mechanism v in the valve body 1 so as to face the spool 2.

  The valve mechanism v incorporates a sleeve portion 4 of the connector 3 into the valve body 1, and an orifice member 5 is fixed to the sleeve portion 4, and a plunger 6 is slidable inward of the orifice member 5. Incorporated. A large-diameter orifice 7 is formed at the center of the orifice member 5, and a small-diameter orifice 8 is formed outside the large-diameter orifice 7. The plunger 6 has a discharge passage 9 formed on the axis thereof, and a communication hole 10 for guiding the discharge passage 9 to the orifice member 5.

  The plunger 6 as described above is provided with a first pressure receiving surface 11 on the side opposite to the orifice member 5 and a second pressure receiving surface 12 on the orifice member 5 side. The second pressure receiving surface 12 faces the chamber 13 and faces the orifice member 5 and the plunger 6. The pressure chamber 13 facing the first pressure receiving surface 11 is communicated with a pump port 15 formed in the valve body 1 through a small hole 14 formed in the sleeve portion 4. A spring 16 is interposed between the orifice member 5 facing the second pressure receiving surface 12 and the plunger 6.

When a pressure fluid flows from the pump port 15, the fluid flows from the fixed orifice 17 into the sleeve portion 4, and the discharge channel 9 → the communication hole 10 → the large diameter orifice 7 or the small diameter orifice 8 → the connector 3. It is supplied to an actuator (not shown) via the discharge port 18. When the fluid passes through the fixed orifice 17 as described above, a differential pressure is generated before and after the fixed orifice 17. The upstream pressure acts on the first pressure receiving surface 11, and the downstream pressure is the second pressure. It acts on the pressure receiving surface 12. Accordingly, the area of the first pressure receiving surface 11 is S1, the pressure upstream of the fixed orifice 17 is P1, the area of the second pressure receiving surface is S2, the pressure downstream of the fixed orifice 17 is P2, and the spring When the spring force of 16 is F, the plunger 6 is
S1 x P1 = (S2 x P2) + F
Keep the balance position under the conditions of.

  When the plunger 6 is spaced from the orifice member 5, both the large-diameter orifice 7 and the small-diameter orifice 8 are opened, and the total opening area thereof becomes the opening area of the orifice, so that a large flow rate flows. On the other hand, when the plunger 6 contacts the orifice member 5, the large diameter orifice 7 is closed, and only the small diameter orifice 8 is opened. Therefore, in this case, the opening area of the small-diameter orifice 8 becomes the opening area of the orifice, and the flow rate is limited as compared with the case where the large-diameter orifice 7 is opened.

  Further, the spool 2 incorporated in the valve body 1 is opposed to the plunger 6 so that the pressure on the downstream side of the fixed orifice 17 acts on one surface which is the opposed surface. The other surface of the plunger 6 faces a back pressure chamber 20 with a spring 19 interposed. The back pressure chamber 20 communicates with the downstream side of the orifices 7 and 8 via a passage 21. I am letting. The opening of the drain port 22 of the spool 2 thus configured is controlled according to the amount of movement when the spool 2 moves against the spring 19, and to the actuator according to the opening of the drain port 22. The flow rate distribution between the supply flow rate and the return flow rate to the drain port 22 is controlled.

When assembling the flow control valve as described above, the valve mechanism v is first assembled and then screwed while inserting the screw 23 formed on the outer periphery of the connector 3 into the valve body 1.
Japanese Patent Publication No. 3-550

  In the conventional flow control valve as described above, when assembling it, the screw 23 formed on the outer periphery of the connector 3 is screwed in while being inserted into the valve body 1, but the position where the screw 23 is tightened cannot be specified. For this reason, the position in the rotational direction of the valve mechanism v with respect to the valve body 1 cannot be specified during assembly. As a result, the position of the small hole 14 in the rotational direction cannot be specified. For this reason, the relative position between the small hole 14 and the pump port 15 is not constant according to various situations during assembly. However, the pressure in the pressure chamber 13 changes depending on the position of the small hole 14 with respect to the pump port 15. For example, if the small hole 14 faces the pump port 15, the pressure in the pressure chamber 13 is almost the same as the pressure in the pump port 15. However, if the small hole 14 is in a position opposite to the pump port 15, the pressure in the pressure chamber 13 is slightly lower than the pressure in the pump port 15.

If the pressure in the pressure chamber 13 varies in this way, the control characteristics vary depending on the individual flow control valves, and the quality of the flow control valves cannot be kept constant.
An object of the present invention is to provide a flow rate control valve having a constant control characteristic so that a small hole can always be maintained at a constant position.

The first invention incorporates a valve mechanism into a valve body in which a pump port is formed, and slidably incorporates a spool so as to face the valve mechanism. The valve mechanism has a sleeve attached to a connector screwed to the valve body. while assembled in series in the axial direction, within the sleeve, to fix the orifice member, a plunger which is slidably also inwardly from the orifice member is provided, in the orifice member provided with the first orifice The plunger is provided with a second orifice having an opening area different from that of the first orifice, and is provided with a discharge passage communicating with the orifice, and the plunger is maintained at a distance from the orifice member. throttle resistance is imparted by the first orifice, with the plunger in contact with the orifice member While the configuration throttle resistance of the second orifice is applied to the plunger, a first pressure receiving surface located on the opposite side, and a second pressure receiving surface located on the orifice member side provided with the orifice member The pressure from the pump port is guided to the first pressure receiving surface side through a small hole formed in the sleeve, the pressure guided to the pump port is applied to one end of the spool, and the first orifice or the second The pressure on the downstream side of the orifice is applied to the other end of the spool, the pump port is connected to the drain port by the pressure balance at both ends of the spool, and the flow rate flowing from the pump port is discharged from the connector, and the drain port It is premised on a flow control valve that distributes to the flow rate that flows out to the flow.

  While presupposing the flow control valve described above, the present invention prevents the sleeve from coming out of the connector and enables its rotation, and assembles the connector and the sleeve, while the end face of the sleeve facing the connector side. In addition, a groove for a rotary tool whose relative relationship with the small hole is specified in advance is formed, and a rotary tool such as a screwdriver is fitted in the groove to rotate the connector and the sleeve relative to each other, whereby the small hole formed in the sleeve is formed. It is characterized in that the position in the relative rotation direction can be adjusted.

  According to the first aspect of the present invention, the position of the small hole can be freely adjusted by inserting the rotary tool in the rotary tool groove whose relative relationship with the small hole is specified and rotating the sleeve. Therefore, the position of the small hole can be made constant, and the quality of the flow control valve can be kept constant.

  In the flow control valve of this embodiment, a spool 32 is slidably incorporated in the valve body 31 and a valve mechanism v is incorporated in the valve body 31 so as to face the spool 32.

  The valve mechanism v includes a sleeve 34 connected in series to a connector 33 and a plunger 35 and an orifice member 36 incorporated in the sleeve 34. The connector 33 has a through-hole 37 formed along the axis thereof, and a screw 38 formed on the outer periphery of a portion to be inserted into the valve body 31. Therefore, the connector 33 is screwed to the valve body 31 by inserting and turning the screw 38 of the connector 33 into the valve body 31.

  The sleeve 34 has its tip inserted into the through hole 37 of the connector 33, and an annular groove 39 is formed on the outer periphery of the insertion portion, and a C-ring 40 is fitted in the annular groove 39. An annular recess 41 corresponding to the annular groove 39 is formed on the inner surface of the through hole 37 of the connector 33. The C-ring 40 fitted in the annular groove 39 can be reduced in diameter in the annular groove 39 to be smaller than the inner diameter of the through hole 37. Therefore, the C ring 40 can be reduced in diameter and inserted into the through hole 37 together with the sleeve 34. Then, when the sleeve 34 is inserted into the through-hole 37 with the C-ring 40 fitted, the annular groove 39 and the annular recess 41 are made to coincide with each other, the C-ring 40 expands by elasticity and fits into the annular recess 41.

In the state where the C-ring 40 is fitted in the annular recess 41 as described above, the sleeve 34 is rotatable with respect to the connector 33, but is prevented from coming off in the axial direction. A rotary tool groove B is formed at the distal end of the sleeve 34 that can be rotated in this manner, that is, at the insertion end inserted into the connector 33. The rotary tool groove B is, for example, a groove into which the tip of a flat screwdriver fits. If a flat screwdriver inserted from the outside of the through hole 37 of the connector 33 is inserted into the rotary tool groove B and the screwdriver is turned, the sleeve 34 can be turned freely from the outside.
An O-ring 44 is fitted to a portion of the outer periphery of the sleeve 34 that contacts the valve main body 31 as described above.
Further, a flange portion 42 is formed at the inner end of the sleeve 34, that is, the end opposite to the connector 33, and a plurality of notches 43 are formed in the flange portion 42.
The notch 43 of the flange portion 42 functions with a fixed orifice 58, which will be described later, and generates pressure loss before and after them. Therefore, if the desired flow rate characteristic can be obtained with only the fixed orifice 58, the notch 43 is unnecessary.

An orifice member 36 is press-fitted and fixed in the sleeve 34 as described above, and a large-diameter orifice 45 which is the first orifice of the present invention is formed in the orifice member 36. In addition, a plunger 35 is slidably incorporated inward of the orifice member 36. The plunger 35 thus formed has an annular convex portion 46 formed on the outer periphery of a substantially central portion in the axial direction, and the sleeve 34 has a stopper portion 47 formed of a stepped portion reduced in diameter on the inner diameter side. A spring 48 is interposed between the annular convex portion 46 and the orifice member 36 so that the annular convex portion 46 normally contacts the stopper portion 47.

In addition, a first pressure chamber 49 is formed between the annular convex portion 46 and the stopper portion 47, and the first pressure chamber 49 is formed in the valve body 31 through a small hole 50 formed in the sleeve 34. The pump port 51 is communicated. The small holes 50 are positioned on the same axis as the rotary tool groove B described above. Therefore, the position of the small hole 50 in the rotation direction can be specified by the position of the rotary tool groove B. However, since two grooves B for the rotary tool are formed in the diameter direction of the sleeve 34, any one of the grooves is marked and only the marked groove is positioned on the same straight line as the small hole 50. I am doing so.
Further, one side surface of the annular convex portion 46 facing the first pressure chamber 49 is a first pressure receiving surface 52, and a space between the plunger 35 and the orifice member 36 is a second pressure chamber 53. An end surface of the plunger 35 facing the pressure chamber 53 is a second pressure receiving surface 54.

Further, the plunger 35 is formed with a discharge passage 55 on its axis , and a small-diameter orifice 56 which is the second orifice of the present invention is formed on the most downstream side of the discharge passage 55. A plurality of communication holes 57 that allow the discharge flow channel 55 to communicate with the second pressure chamber 53 are formed around the small-diameter orifice 56.

  In the state where the plunger 35 as described above is separated from the orifice member 36 as shown in the drawing, the discharge flow passage 55 communicates with the small diameter orifice 56 and the communication hole 57, but the small diameter orifice 56 and the communication hole 57. The total of the opening areas is larger than the opening area of the large-diameter orifice 45. Accordingly, the fluid flowing from the discharge flow channel 55 to the through hole 37 is given a throttle resistance by the large-diameter orifice 45.

On the other hand, when the plunger 35 comes into close contact with the orifice member 36, the communication between the communication hole 57 and the through hole 37 is blocked, so that the fluid flowing from the discharge flow path 55 to the through hole 37 is caused by the small diameter orifice 56. A diaphragm resistance is applied. That is, the large-diameter orifice 45 functions or the small-diameter orifice 56 functions according to the movement position of the plunger 35, but the movement position of the plunger 35 is determined by the first and second pressure chambers 49 and 53. Pressure. That is, the area of the first pressure receiving surface 52 is S1, the pressure of the first pressure chamber 49 is P1, the area of the second pressure receiving surface 54 is S2, the pressure of the second pressure chamber 53 is P2, and the spring 48 The plunger 35, where F is the spring force of
S1 x P1 = (S2 x P2) + F
Keep the balance position under the conditions of.

The fixed orifice 58 formed in the sleeve 34 and the notch 43 of the flange portion 42 determine the pressure P1 and the second pressure chamber P2 of the first pressure chamber 49. The fixed orifice 58 and the notch 43 are formed in a passage process for communicating the pump port 51 and the discharge flow path 55, and the pressure upstream of the fixed orifice 58 and the notch 43 is introduced into the first pressure chamber 49. The downstream pressure is introduced into the second pressure chamber 53.

  The spool 32 has the end surface opposite to the valve mechanism v facing the back pressure chamber 59, and the spring force of the spring 60 provided in the back pressure chamber 59 usually causes the surface facing the valve mechanism v to face. The sleeve 34 is brought into pressure contact with the flange portion 42. In this pressure contact state, the drain port 61 is completely blocked. When the spool 32 moves against the spring 60, the opening degree of the drain port 61 is controlled according to the amount of movement.

  The back pressure chamber 59 communicates with the downstream side of the large-diameter orifice 45 through a communication passage 62 formed in the valve main body 31 and a communication port 63 formed in the sleeve 34. An opening is formed between the annular groove 39 and the orifice member 36 described above. An O-ring 64 is fitted between the annular groove 39 and the communication port 63.

  The O-ring 64 and the O-ring 44 also function to prevent the sleeve 34 from rotating carelessly due to the elasticity of its tightening allowance.

  In order to assemble the flow control valve as described above, first, the sleeve 34 is assembled to the connector 33 to assemble the valve mechanism v. The assembled valve mechanism v is assembled to the valve body 31. At this time, the screw 38 of the connector 33 is screwed while being inserted into the valve body 31. At this time, when the screw 38 is tightened, a minus driver, for example, is inserted from the outside of the through hole 37, and the minus driver is inserted into the rotary tool groove B of the sleeve 34 to rotate the sleeve 34. Specify the position in the rotation direction.

  As described above, since the position of the small hole 50 in the rotation direction can be freely adjusted, it is possible to completely eliminate the conventional problem that the position of the small hole 50 varies and the control characteristics vary.

  When pressure fluid flows from the pump port 51, the pressure of the fluid is guided to the first pressure chamber 49 through the small hole 50 and acts on the end surface of the spool 32 through the notch 43 of the flange portion 42. . Further, the pressure fluid that has flowed into the pump port 51 as described above flows into the discharge passage 55 via the fixed orifice 58 and the notch 43, and from the small diameter orifice 56 through the large diameter orifice 45 to the through hole 37. Is supplied to the actuator from the discharge port 37a which is the tip of the nozzle.

  The pressure on the discharge port 37a side at this time is guided to the second pressure chamber 53 and also to the back pressure chamber 59 via the communication port 63 and the communication passage 62. Therefore, the spool 32 maintains a position where the pressure action of the pump port 51, the pressure action of the back pressure chamber 59 and the spring force of the spring 60 are balanced, and controls the opening degree of the drain port 61 at that position. When the opening degree of the drain port 61 is determined in this way, the flow rate flowing from the pump port 51 is distributed according to the opening degree.

  Further, if the amount of inflow from the pump port 51 increases, the differential pressure before and after the fixed orifice 58 increases. As the differential pressure increases, the acting force on the first pressure receiving surface 52 in the first pressure chamber 49 overcomes the total force of the acting force of the second pressure receiving surface 54 in the second pressure chamber 53 and the spring force of the spring 48. For example, the plunger 35 moves against the spring 48 and contacts the orifice member 36. When the plunger 35 comes into contact with the orifice member 36, only the small-diameter orifice 56 functions, and accordingly, the supply flow rate to the actuator flowing out from the discharge port 37a decreases. Further, if the amount of inflow from the pump port 51 is reduced, the pressure difference between the fixed orifice 58 and the notch 43 is reduced accordingly, so that the pressure difference between the first pressure chamber 49 and the second pressure chamber 53 is also reduced. Become. Therefore, the plunger 35 is moved away from the orifice member 36 by the spring force of the spring 48, and the large diameter orifice 45 is caused to function.

It is sectional drawing of the flow control valve of this invention. It is the II-II sectional view taken on the line of FIG. It is sectional drawing of the conventional flow control valve.

Explanation of symbols

31 Valve body 32 Spool v Valve mechanism 33 Connector 34 Sleeve 35 Plunger 36 Orifice member 45 Large diameter orifice B Groove for rotary tool 50 Small hole 51 Pump port 52 First pressure receiving surface 54 Second pressure receiving surface 55 Discharge flow path 56 Small diameter orifice 61 Drain port 64 O-ring

Claims (2)

A valve mechanism is incorporated into the valve body in which the pump port is formed, and a spool is slidably incorporated so as to face the valve mechanism, and the above-mentioned valve mechanism assembles a sleeve in series in the axial direction to a connector screwed to the valve body. on the other hand, within the sleeve, to fix the orifice member, this providing a plunger which is slidable in inward from the orifice member is provided with a first orifice in the orifice member, the said plunger the A second orifice having an opening area different from that of the first orifice is provided, and a discharge flow path communicating with the orifice is provided. When the plunger is spaced from the orifice member, the first orifice restricts the orifice . resistance is applied, in a state where the plunger is in contact with the orifice member second orifice While throttle resistance by the scan is configured to be applied to the plunger, a first pressure receiving surface located on the opposite side, and a second pressure receiving surface located on the orifice member side provided with the orifice member, the sleeve The pressure from the pump port is guided to the first pressure receiving surface side through the formed small hole, the pressure guided to the pump port is applied to one end of the spool, and the first orifice or the second orifice is The pressure on the downstream side is applied to the other end of the spool, the pump port is connected to the drain port by the pressure balance at both ends of the spool, and the flow rate flowing from the pump port is discharged to the connector and the flow rate to the drain port. In the flow control valve that distributes to the flow rate, it prevents the sleeve from coming out of the connector and enables its rotation. While assembling the sleeve, the end surface of the sleeve facing the connector is formed with a groove for a rotary tool whose relative relationship with the small hole is specified in advance, and a rotary tool such as a screwdriver is fitted in this groove to connect the connector and the sleeve. A flow rate control valve configured to be able to adjust the position of the small hole formed in the sleeve in the relative rotation direction by relatively rotating the.   2. The flow rate control valve according to claim 1, wherein an O-ring is fitted around the sleeve, and the rotation of the sleeve is restricted by the force of the tightening amount of the O-ring.

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