JP2008128426A - Valve element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a valve element for preventing throttle resistance from being greatly varied depending on the passing direction of fluid. <P>SOLUTION: The valve element 1 is seated on/off an annular valve seat 3 which is provided on the midway of a flow path 2 allowing a flow in both directions, for opening/closing the flow path 2. It comprises a conical portion 1a formed on the front side directed to the valve seat 3 so as to be gradually tapered toward the valve seat 3, and a tapered portion 1b formed on the back side of the conical portion 1a so as to be inclined inversely to the conical portion 1a. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement of a valve body.

  For example, the valve body is embodied in a damping valve provided at the tip of a piston rod to which a piston of a hydraulic shock absorber is connected. For example, as shown in FIG. A flow path 104a that connects the rod side chamber 102 and the piston side chamber 103 defined by the piston 101 in the cylinder 100 is formed in the piston rod 104, and a poppet type valve element 105 that is accommodated in the flow path 104a is known. The valve body 105 is configured to be able to move back and forth in the axial direction with respect to the piston rod 104 and to be seated on and off from a cylindrical valve seat member 106 fitted to the inner periphery of the piston rod 104.

  Further, the valve body 105 is seated on the annular end portion of the valve seat member 106 to block communication between the rod side chamber 102 and the piston side chamber 103, and conversely retracts from the annular end portion of the valve seat member 106. When separated, the rod side chamber 102 and the piston side chamber 103 can be communicated with each other through an annular gap formed between the inner edge of the valve seat member 106 and the valve body 105.

Therefore, in such a valve body 105, the size of the area of the annular gap can be adjusted in accordance with the amount by which the valve body 105 is retracted from the annular valve seat 106, whereby the operation of passing through the annular gap. The generated damping force of the hydraulic shock absorber can be adjusted by adjusting the magnitude of the resistance given to the oil flow (see, for example, Patent Document 1).
Japanese Patent Laying-Open No. 2004-301182 (FIG. 2)

  However, the valve of Patent Document 1 is set to have both effects in which damping force is expected to be generated in the expansion stroke and the compression stroke of the hydraulic shock absorber, and the direction of the flow of hydraulic oil is reversed in the expansion stroke and the compression stroke. .

  When the hydraulic shock absorber is in the compression stroke and the hydraulic fluid flows around the poppet type valve body 105 from the lower side to the upper side in FIG. 4, the valve body 105 with respect to the direction of the hydraulic oil flow. Therefore, the fluid force acting on the valve body 105 by the flow of hydraulic oil acts to center the valve body 105 at the center of the flow path 104a. On the other hand, when the hydraulic shock absorber is in the expansion stroke and the hydraulic fluid flows around the poppet type valve body 105 from the upper side to the lower side in FIG. 4, the valve body 105 with respect to the direction of the hydraulic oil flow. The fluid force acting on the valve body 105 due to the flow of hydraulic oil becomes difficult to center the valve body 105 to the center of the flow path 104a, and the valve body 105 becomes the center of the flow path 104a. May not be positioned properly.

  Then, in the extension stroke and the compression stroke, the throttle resistance generated when the hydraulic oil passes through the valve is significantly different, and the damping characteristic (damping force characteristic with respect to the piston speed) is significantly different. There is a case where the diaphragm resistance in the compression stroke is not stable and a stable damping force cannot be obtained.

  Therefore, the present invention was devised in order to improve the above-described problems, and the object of the present invention is to provide a valve body that can suppress a significant difference in throttle resistance in the fluid passage direction. Is to provide.

  In order to achieve the above-described object, the valve body of the present invention is directed to the valve seat in a valve body that opens and closes the annular valve seat provided in the middle of the flow path that allows bidirectional flow and opens and closes the flow path. A conical portion that is formed on the front side and tapers toward the valve seat side, and a tapered portion that is formed on the back side of the conical portion and is inclined opposite to the conical portion. To do.

  According to the valve body of the present invention, the fluid force resulting from the fluid flow acts so as to center the valve body at the center of the flow path regardless of the flow direction of the fluid. Aperture resistance is not significantly different.

  Moreover, since the fluid force resulting from the fluid flow acts so as to center the valve body at the center of the flow path regardless of the fluid flow direction, the throttle resistance is stabilized regardless of the fluid flow direction.

  Thus, by applying the valve body to the valve, it is possible to prevent the throttle resistance from being significantly different in the fluid passage direction and to stabilize the throttle resistance. When the valve is embodied in a shock absorber, the damping characteristic can be adjusted as intended, and it is possible to suppress a situation where the damping characteristic of the shock absorber is significantly different from that of the compression stroke. It is.

  In addition, the fluid force resulting from the fluid flow acts so as to center the valve body at the center of the flow path regardless of the direction of flow of the fluid, so a support member for positioning the valve body at the center of the flow path is unnecessary. Thus, the configuration of the valve can be simplified, and the operability and durability of the valve body are improved in that the omission of the support member reduces the frictional resistance against the advancement and retraction of the valve body.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of a valve in which a valve body according to an embodiment of the present invention is embodied. FIG. 2 is a longitudinal sectional view of a valve in an opened state in which a valve body according to an embodiment of the present invention is embodied. FIG. 3 is a side view of a valve body according to a modification of the embodiment of the present invention.

  As shown in FIG. 1, a valve body 1 according to an embodiment is seated on an annular valve seat 3 provided in the middle of a flow path 2 that allows bidirectional flow, as shown in FIG. 2 is set to open and close. Specifically, a conical portion 1a formed on the front side facing the valve seat 3 and tapered toward the valve seat 3 side, and formed on the back side of the conical portion 1a. Thus, it is configured to include a tapered portion 1b that is inclined opposite to the conical portion 1a, and is embodied in, for example, a valve that is incorporated at the tip of a piston rod 4 connected to a piston (not shown) of the shock absorber.

  In this way, when the valve including the valve body 1 is incorporated at the tip of the piston rod 4 of the shock absorber, the flow path 2 has, for example, a lateral hole 4a provided in the piston rod 4 and a lateral side as shown in FIG. The valve seat 3 is formed by one end of a cylindrical body 5 fitted in the vertical hole 4b, and the valve body 1 is movably accommodated in the vertical hole 4b. Thus, the conical portion 1a is brought into and out of contact with the valve seat 3 by being brought into and out of contact with the valve seat 3.

  The lateral hole 4a communicates with a rod side chamber 6 defined by a piston in the shock absorber, and the other vertical hole 4b communicates with a piston side chamber 7 defined by a piston in the shock absorber. When the valve 1 is separated from the valve seat 3 and the valve is in the open state, a resistance is applied to the flow of fluid that exchanges the rod side chamber 6 and the piston side chamber 7 to generate a throttling resistance. On the contrary, when the valve body 1 is seated on the valve seat 3 by generating a force, the valve is closed and the communication between the rod side chamber 6 and the piston side chamber 7 is cut off.

  The upper side of the valve body 1 in FIG. 1 is connected to a feed screw mechanism (not shown) provided at the upper end of the piston rod 4, and moves forward and backward with respect to the valve seat 3 by operating the mechanism. When the valve body 1 is retracted from the valve seat 3 and separated from the valve seat 3, as shown in FIG. 2, there is a gap between the inner edge of the valve seat 3 and the conical portion 1 a of the valve body 1. An annular gap S is formed in the valve, and the valve brings the rod side chamber 6 and the piston side chamber 7 into communication with each other. The annular gap S functions as a throttle, and resists the flow of fluid passing through the annular gap S. The throttle resistance corresponding to the cross-sectional area of the annular gap S is generated, and the cross-sectional area of the annular gap S can be adjusted by the retraction amount of the valve body 1 with respect to the valve seat 3, and the throttle resistance is adjusted by the adjustment. Is possible.

  In the case of the valve body 1, the part to be attached to and detached from the valve seat 3 is a conical portion 1 a, and the conical portion 1 a has a conical shape in which the inclination angle with respect to the axis of the ridge line changes in the middle. The rate of change of the cross-sectional area of the annular gap S with respect to the axial displacement of the valve body 1 with respect to the valve seat 3 is different at the tilt angle change point, and in particular, a high damping force is generated. Since the amount of change in the axial displacement of the valve body 1 with respect to the valve seat 3 of the damping element 1 becomes small when the damping characteristic is expected, the damping characteristic can be easily adjusted when a high damping force is expected to be generated. Yes.

  Thus, the shape of the conical portion 1a may be a simple conical shape, or may be a conical shape whose inclination angle with respect to the axis of the ridge line changes one or more times along the way.

  Next, the operation of the valve body 1 will be described. When the valve body 1 is separated from the valve seat 3 and the valve is in the open state and the shock absorber extends, as shown by the arrow A in FIG. In addition, since the fluid is directed from the rod side chamber 6 to the piston side chamber 7, the fluid passes through the flow path 2 from the upper side to the lower side in FIG. 2, and the small diameter side of the tapered portion 1 b faces the flow of the fluid, The fluid force due to the fluid flow acts to center the valve body 1 at the center of the vertical hole 4b.

  On the other hand, when the valve body 1 is separated from the valve seat 3 and the valve is in the open state and the shock absorber is compressed, the fluid flows from the piston side chamber 7 to the rod side chamber as shown by the arrow B in FIG. 2, the fluid passes through the flow path 2 from the lower side to the upper side in FIG. 2, the tip of the conical portion 1 a faces the flow of the fluid, and the fluid force due to the flow of the fluid is the valve body. 1 is centered on the center of the vertical hole 4b.

  Therefore, even if this valve body 1 is applied to a valve having a flow path 2 that allows bidirectional flow, the fluid force caused by the flow of fluid in either direction of fluid flow causes the valve body 1 to flow through the flow path 2. Therefore, the throttling resistance generated when passing through the valve does not vary significantly depending on the direction of fluid flow.

  Moreover, since the fluid force resulting from the fluid flow acts so as to center the valve body 1 at the center of the flow path 2 regardless of the fluid flow direction, the throttle resistance generated regardless of the fluid flow direction is stabilized. .

  In this way, by applying the valve body 1 to the valve, it is possible to prevent the throttle resistance from being significantly different in the fluid passage direction and to stabilize the throttle resistance. When the applied valve is embodied in a shock absorber, the damping characteristics can be adjusted as intended, and it is possible to suppress a situation where the damping characteristics of the shock absorber are significantly different. It becomes.

  Moreover, since the fluid force resulting from the fluid flow acts so as to center the valve body 1 at the center of the flow path 2 regardless of the flow direction of the fluid, the valve body 1 is positioned at the center of the flow path 2. The support member is not required, the valve configuration can be simplified, and the operability and durability of the valve body 1 are improved in that the omission of the support member reduces the frictional resistance against the advancement and retraction of the valve body 1. Will do.

  Like the valve formed in the tip of the piston rod 4 of the shock absorber, the length from the tip of the valve body to the portion supported in the flow path is very long, and the fluid force acting on the valve body is attenuated. The valve body 1 of the present invention is particularly suitable for a valve that has a great influence on the characteristics, and effectively exhibits the above-described action.

  Further, since the valve body only needs to have a conical portion and a tapered portion, in addition to the shape described above, as shown in FIG. 3, the maximum diameter of the tapered portion 9b of the valve body 9 is the conical portion 9a. The step diameter 9c may be formed between the tapered portion 9b and the conical portion 9a. In this case, the maximum diameter of the conical portion 9a is the inner diameter of the cylindrical body 5. The conical portion 9a is set to have a smaller diameter than the circumferential diameter so that the conical portion 9a can be inserted into the cylindrical body 5, and the stepped portion 9c is set on and off from the valve seat 3.

  The valve body 9 shown in FIG. 3 is configured to close the valve by sitting on the valve seat 3 with the stepped portion 9c that is an annular flat surface. it can. About another effect, it is the same as that of the valve body 1 in above-described one Embodiment.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a longitudinal cross-sectional view of the valve | bulb which the valve body in one embodiment of this invention embodied. It is a longitudinal cross-sectional view of the valve of the valve opening state which the valve body in one embodiment of this invention embodied. It is a side view of the valve body in the modification of one embodiment of this invention. It is a longitudinal cross-sectional view of the valve | bulb of the buffer which embodied the conventional valve body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,9 Valve body 1a, 9a Conical part 1b, 9b Tapered part 2 Flow path 3 Valve seat 4 Piston rod 4a Horizontal hole 4b Vertical hole 5 Cylindrical body 6 Rod side chamber 7 Piston side chamber 9c Step part S Annular clearance

Claims (2)

In a valve body that opens and closes a flow path by opening and closing a ring-shaped valve seat provided in the middle of a flow path that allows bidirectional flow, the valve body is formed on the front side facing the valve seat and tapers toward the valve seat side. A valve body comprising: a conical portion; and a tapered portion formed on the back side of the conical portion and inclined in reverse to the conical portion. The maximum diameter of the tapered portion is set to be larger than the maximum diameter of the conical portion, a step portion is formed between the tapered portion and the conical portion, and the step portion is attached to and detached from the valve seat. 1. The valve body according to 1.

Images