JP5057392B2 - Rotary valve - Google Patents

Description

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

  Conventionally, in this type of rotary valve, a hollow hole is provided in the piston rod of the shock absorber to form a housing, and a cylindrical valve body is rotatably inserted into the housing. A pair of ports that communicate with the inside and outside of the housing and face each other are formed, and a pair of orifice holes that communicate with the inside and outside of the valve body and face each other so as to face each other and face the ports of the housing are formed. What is provided is known.

In this conventional rotary valve, by rotating the valve body with respect to the housing, the degree of overlap (wrap) between the port and the orifice hole is changed to change the flow passage area, and the hydraulic oil is transferred to the rotary valve. It is possible to change the pressure loss when passing through the valve, and to adjust the damping force generated by the shock absorber.
JP 2008-39065 A (FIG. 1)

  Specifically, the rotary valve described above is provided in the middle of a bypass passage that bypasses the main damping passage provided on the piston of the shock absorber and is opened and closed by the leaf valve, and communicates the upper chamber and the lower chamber. In order to adjust the damping characteristics (characteristics of the generated damping force with respect to piston speed) over a wide range from soft to hard, in addition to a pair of small orifice areas, two pairs of large orifice areas are used. Parallel in the bypass.

  This bypass path is branched from an orifice hole and a second orifice hole provided in the middle from the lower chamber to the upper chamber, and the bypass path branched by the second orifice hole is a partition provided on the outer periphery of the piston rod. A chamber formed by the member and a passage provided in the partition member are formed and communicated with the upper chamber, and the passage is opened and closed by a leaf valve. The bypass path branched by the orifice hole is formed by a sub-passage that is provided in the piston and bypasses the main damping passage, and communicates with the upper chamber.

  When the damping force is soft, the orifice area is made to face the port to increase the flow area, but the bypass path leading to the orifice hole leads to the second orifice hole restricted by the leaf valve. Since no resistance element is provided for the bypass passage, when the damping force is softened, the flow rate of the hydraulic oil passing through the orifice hole becomes very large.

  Here, the valve body of the rotary valve is cylindrical as described above, and two orifice holes are provided to allow passage of a large flow rate, and these orifice holes face each other and face each other. Therefore, when the flow of hydraulic oil collides from the front in the valve body, especially when the flow rate passing through the orifice hole increases, vortices are generated in the valve body or aeration is generated, causing abnormal noise. There is.

  Accordingly, the present invention has been developed to improve the above-described problems, and an object of the present invention is to provide a rotary valve capable of suppressing the generation of abnormal noise.

In order to solve the above-described object, the problem solving means in the present invention includes a cylinder, a piston rod that is slidably inserted into the cylinder, and is slidably inserted into the cylinder and attached to the outer periphery of the piston rod. A piston having a main damping passage that divides the inside of the cylinder into an upper chamber and a lower chamber and communicates the upper chamber and the lower chamber; and a bypass passage that bypasses the main damping passage and communicates the upper chamber and the lower chamber. The bypass passage is formed by a hollow hole that opens from the tip of the piston rod and communicates with the lower chamber, and a partition member that is mounted on the outer chamber side of the piston rod on the upper chamber side from the piston. A chamber communicated with the upper chamber by a passage formed in the inner chamber, a sub-passage provided in a spacer interposed between the partition member and the piston and communicated with the upper chamber, A pair of first ports provided in the stone rod and arranged eccentrically in the vertical direction communicating the hollow hole and the sub passage, and a second port provided in the piston rod and communicating the hollow hole and the chamber. A cylindrical valve body is formed in the hollow hole so as to be rotatable in the circumferential direction. The valve body is eccentrically arranged in the vertical direction and is opposed to the pair of first ports. A hole and a second orifice hole that can face the second port are provided .

According to the rotary valve of the present invention, the pair of first ports and the pair of first orifice holes corresponding to these ports are arranged eccentrically in the axial direction, so that the orifice holes do not directly face each other and operate. Since the fluid flow is prevented from colliding from the front in the valve body, even if the flow rate of the working fluid passing through each orifice hole increases, vortices and aeration do not occur in the valve body. The generation of abnormal noise can be suppressed.
Since the auxiliary passage in the bypass passage is formed in a spacer interposed between the partition member and the piston, the thickness of the leaf valve and the valve stopper is at least the axial direction compared to the conventional rotary valve. The manufacturing cost is reduced, which is economically advantageous.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially enlarged longitudinal sectional view of a shock absorber to which a rotary valve according to an embodiment of the present invention is applied. FIG. 2 is a side view of the valve body of the rotary valve according to the embodiment of the present invention.

 As shown in FIG. 1, the rotary valve 5 of the present invention is applied to a shock absorber D and used for adjusting a damping force. In this case, in detail, the housing is used as a piston rod 2 and the piston rod 2 is used. A cylindrical valve body 8 is rotatably housed in the circumferential direction.

On the other hand, a shock absorber D to which the rotary valve of the present invention is applied includes a cylinder 1, a piston rod 2 that is slidably inserted into the cylinder 1, and a piston rod 2 that is slidably inserted into the cylinder 1. A piston 3 having main damping passages 3a and 3b that divide the inside of the cylinder 1 into an upper chamber R1 and a lower chamber R2 and communicate the upper chamber R1 and the lower chamber R2, and a main damping passage 3a, A bypass path 4 that bypasses 3b and communicates the upper chamber R1 and the lower chamber R2, and a valve 5 that is provided in the middle of the bypass path 4 and is formed of a cylindrical valve body that changes the flow passage area of the bypass path 4 ; A working fluid such as hydraulic oil is sealed in the cylinder 1. In the shock absorber D, the damping force is adjusted by changing the flow passage area in the bypass passage 4 by the valve 5 described above.
As will be described later, the bypass path 4 has a hollow hole 2a that opens from the tip of the piston rod 2 and communicates with the lower chamber R2, and a partition member that is mounted on the outer chamber R1 side of the piston rod 2 from the piston 3 to the upper chamber R1 side. 7 and a space 11 communicated with the upper chamber R1 by passages 9a and 9b formed in the partition member 7 and a spacer 6 interposed between the partition member 7 and the piston 3. A sub-passage comprising a notch 6c communicating with the upper chamber R1, and a pair of first ports 2g, 2h provided in the piston rod 2 and arranged eccentrically in the vertical direction communicating the hollow hole 2a and the sub-passage; The second ports 2e and 2f are provided in the piston rod 2 and communicate with the hollow hole 2a and the chamber 11.
Further, the tubular valve body 8 is accommodated in the hollow hole 2a so as to be rotatable in the circumferential direction. The valve body 8 is arranged eccentrically in the vertical direction and faces the pair of first ports 2g and 2h, respectively. A pair of first orifice holes 21 and 22 and second orifice holes 19 and 20 that can face the second ports 2e and 2f are provided.

  Although not shown, the upper and lower ends of the cylinder 1 in FIG. 1 are sealed with a sealing member (not shown), and the cylinder 1 is held in a sealed state. When the working fluid is a liquid, when the shock absorber D expands or contracts, the piston rod 2 enters or leaves the cylinder 1 to compensate for the amount of liquid that becomes excessive or insufficient in the cylinder 1. Therefore, although not shown, it is natural that a gas chamber defined by a free piston inserted below the cylinder 1 or a reservoir communicating with the cylinder 1 is provided.

  Hereinafter, each member will be described in detail. The cylinder 1 is formed in a cylindrical shape, and a rod guide (not shown) for slidably supporting the piston rod 2 is provided at the upper end in FIG. .

  The piston rod 2 includes a hollow hole 2a that opens from the lower end in FIG. 1 and faces the lower chamber R2, and a control rod insertion hole 2b that continues to the hollow hole 2a and communicates with an upper end (not shown). A spacer 6 and a partition member 7 are attached to the outer periphery of the piston 3 and an upper chamber R1 side above the piston 3 in FIG.

  A cylindrical valve body 8 of the rotary valve 5 is rotatably accommodated in the hollow hole 2a of the piston rod 2.

  The lower side of the piston rod 2 is set to a small diameter to form a small diameter portion 2c and a step portion 2d, and the small diameter portion 2c has a pair of ports 2g, 2h that communicate the hollow hole 2a to the outside of the piston rod. In addition to the ports 2g and 2h, the upper and lower two pairs of second ports 2e and 2f that communicate with the outside of the piston rod through the hollow hole 2a and that are disposed at an interval of 180 degrees in the circumferential direction and face each other. And are opened.

  One port 2g is arranged eccentrically in the vertical direction in FIG. 1, which is the axial direction with respect to the other port 2h. When one port 2g and the other port 2h are projected onto the axis of the piston rod 2, The projected two images do not overlap with each other, and the one port 2g and the other port 2 do not directly face each other.

  In this embodiment, the second ports 2e and 2f described above are circular, and the ports 2g and 2h are elongated holes along the longitudinal direction of the piston rod 2, but the shape is not limited to this.

  The piston 3 is formed in an annular shape, and when the shock absorber D extends through the upper chamber R1 and the lower chamber R2, the working fluid passes and the main damping passage 3a on the expansion side, the upper chamber R1 and the lower chamber R2 are passed. And a pressure-side main damping passage 3b through which the working fluid passes when the shock absorber D is compressed. The leaf valves V1 and V2 are stacked on the upper and lower sides of the piston 3, respectively, and the lower end serving as the outlet end of the main damping passage 3a is opened and closed by the leaf valve V1, and conversely, the outlet end of the main damping passage 3b. The upper end is opened and closed by a leaf valve V2.

  Therefore, when the shock absorber D is extended, the leaf valve V1 applies a resistance to the flow of the working fluid that passes through the main damping passage 3a on the expansion side and moves from the upper chamber R1 to the lower chamber R2, thereby shock absorber. The other leaf valve V2 generates an extension-side damping force in D, and when the shock absorber D is compressed, the working fluid moves from the lower chamber R2 to the upper chamber R1 through the compression-side main damping passage 3b. A resistance is applied to the flow of the pressure to generate a compression side damping force in the shock absorber D.

  The spacer 6 is formed in a bottomed cylindrical shape, and a hole 6a that allows insertion of the small-diameter portion 2c of the piston rod 2 is provided at the bottom, and a notch 6c that communicates inside and outside is provided in the cylindrical portion 6b. The rod 2 is assembled on the outer periphery of the small diameter portion 2c. In addition, the notch 6c may be provided in the edge part of the cylinder part 6b, and may be provided in the middle of the cylinder part 6b in the shape of a hole. In this embodiment, the spacer 6 is directly stacked on the leaf valve V2 stacked above the piston 3, and functions as a valve stopper that regulates the amount of deflection of the leaf valve V2. Also good.

  The partition member 7 includes an annular valve disk 9 assembled to the outer periphery of the small diameter portion 2c of the piston rod 2, and a bottomed cylindrical cap 10 assembled to the outer periphery of the valve disk 9 and the piston rod 3. The valve disk 9 and the cap 10 partition the room 11 in the upper chamber R1.

  Specifically, the valve disk 9 includes an extension side passage 9a that penetrates the valve disk 9 and a pressure side passage 9b.

  The outlet end of the extension side passage 9a is opened and closed by a leaf valve V3 stacked below the valve disk 9 in FIG. 1, and the extension side passage 9a is a one-way passage that is opened only during the extension stroke of the shock absorber D. The resistance is set by the leaf valve V3 to the set working fluid. On the other hand, the outlet end of the pressure side passage 9b is opened and closed by a leaf valve V4 stacked above the valve disc 9 in FIG. 1, and the pressure side passage 9b is set as a one-way passage that is opened only during the compression stroke of the shock absorber D. The leaf valve V4 provides resistance to the working fluid passing therethrough. Since the bending rigidity of the leaf valves V3 and V4 is set to be smaller than the bending rigidity of the leaf valves V1 and V2 stacked on the piston 3, the valve opening pressure is lower than the valve opening pressure of the leaf valves V1 and V2. The expansion side passage 9a and the pressure side passage 9b are opened by the pressure.

  The cap 10 is formed in a bottomed cylindrical shape, and a hole 10a that allows the small-diameter portion 2c of the piston rod 2 to be inserted is provided at the bottom, and the opening of the cylindrical portion is fitted to the outer periphery of the valve disc 9. Are combined. And between the bottom part of this cap 10 and the valve disc 9, the valve | bulb restraint 12 which is a bottomed cylinder shape and is set to a diameter smaller than the cap 10 is interposed, The said valve | bulb restraint 12 is the bottom part. The leaf valve V3 is set to open outward by preventing the leaf valve V3 from lifting from the inner periphery of the valve disc 9. Further, the valve restraint 12 includes a notch 12b in the cylindrical portion 12a, and the inside and the outside communicate with each other by the notch 12b. In addition, the notch 12b may be provided in the edge part of the cylinder part 12a, and may be provided in the middle of the cylinder part 12a in the shape of a hole.

  Further, the small diameter portion 2c of the piston rod 2 includes, in order from the top in FIG. 1, a valve stopper 13, a leaf valve V4, a valve that is restricted from moving upward with respect to the piston rod 2 by the step portion 2d of the piston rod 2. The disc 9, the leaf valve V 3, the valve restraint 12, the cap 10, the spacer 6, the leaf valve V 2, the piston 3, the leaf valve V 1, and the annular valve stopper 14 for regulating the leaf valve V 1 are assembled. Each member described above is fixed to the piston rod 2 by a piston nut 15 screwed to the lowermost end of the piston rod 2.

  Thus, in a state where each member is assembled and fixed to the piston rod 2, the ports 2 g and 2 h provided on the piston rod 2 face the cylindrical portion 6 b of the spacer 6, and further, the cylindrical portion 12 a of the valve retainer 12. The second ports 2e and 2f provided on the piston rod 2 face each other, and the hollow hole 2a facing the lower chamber R2 is connected to the upper chamber R1 via the ports 2g and 2h and the notch 6c provided on the spacer 6. The second port 2e, 2f, the notch 12b provided in the valve retainer 12, the chamber 11 partitioned by the valve disc 9 and the cap 10, and the extension side passage 9a and the pressure side passage 9b provided in the valve disc 9. Via the upper chamber R1.

  Therefore, in this embodiment, the bypass path 4 includes the hollow hole 2a that opens from the tip of the piston rod 2 and communicates with the lower chamber R2, the ports 2g and 2h, the notch 6c provided in the spacer 6, the second port 2e, 2f, a notch 12b provided in the valve restraint 12, a chamber 11, an extension side passage 9a and a pressure side passage 9b. In this case, the passage formed in the partition member 7 is the extension side provided in the valve disc 9. The passage 9 a and the pressure side passage 9 b are formed, and the sub passage is formed by a notch 6 c provided in the spacer 6.

  The extension side passage 9a and the pressure side passage 9b functioning as passages provided in the partition member 7 are set to be one-way, and are opened and closed by the leaf valves V3, V4. Therefore, the leaf valves V3, V4 are opened. The corresponding extension side passage 9a and pressure side passage 9b are closed until the pressure is reached, and the bypass passage 4 is connected to the upper chamber R1 and the lower chamber via the hollow hole 2a, the ports 2g, 2h, and the notch 6c provided in the spacer 6. R2 is communicated.

  Subsequently, the cylindrical valve body 8 in the rotary valve 5 accommodated in the hollow hole 2a of the piston rod 2 has its outer peripheral surface in sliding contact with the inner peripheral surface of the hollow hole 2a, and can be rotated in the circumferential direction. The upper end of the piston rod 2 is connected to the control rod 16 inserted into the control rod insertion hole 2b.

  The control rod 16 is connected to an output shaft of a stepping motor (not shown) fixed to the upper end of the piston rod 2, and the valve body 8 is moved in the circumferential direction with respect to the piston rod 2 by driving the stepping motor. Step rotation can be performed for each predetermined rotation angle.

  Further, a cylindrical stopper 18 is press-fitted in the hollow hole 2a of the piston rod 2 and below the valve body 8 in FIG. 1, and this stopper 18 prevents the valve body 8 from falling off the piston rod 2. is doing. Further, a cylindrical resin bearing 17 is interposed between the stopper 18 and the valve body 8 to ensure smooth rotation of the valve body 8.

  The valve body 8 includes two pairs of upper and lower second orifice holes 19 and 20 that can communicate with the inside and outside of the side portion and face the second ports 2e and 2f formed in the small diameter portion 2c of the piston rod 2, and the ports 2g, A pair of orifice holes 21 and 22 that can face each other 2h are provided.

  As shown in FIGS. 1 and 2, each of the second orifice holes 19 and 20 includes circular holes 19a and 20a and slits 19b and 20b communicated with the circular holes 19a and 20a along the circumferential direction, respectively. And the slits 19b and 20b themselves pass through the thickness of the valve body 8 and communicate with the inside and outside of the valve body 8, and the paired circular holes 19a and 20a are 180 degrees in the circumferential direction. Are arranged so as to face each other and face each other.

  Further, as shown in FIGS. 1 and 2, the orifice holes 21 and 22 are elongated holes 21a (22a) having the same shape as the port 2g (2h) along the axis of the valve body 8, and elongated holes along the circumferential direction. The long hole 21a (22a) communicates with the inside and outside of the valve body 8, but the groove 21b (22b) itself is the thickness of the valve body 8. The valve body 8 is not communicated with the inside and outside of the valve body 8 only through the long hole 21a (22a). The one orifice hole 21 is arranged in the valve body 8 so as to be eccentric in the axial direction with respect to the other orifice hole 22, and the elongated hole 21a is a long hole when facing the one port 2g completely. 22b faces the other port 2h. When one orifice hole 21 and the other orifice hole 22 are projected onto the axis of the valve body 8 that coincides with the axis of the piston rod 2, the projected two are overlapped. It is supposed not to be.

  The center of the long hole 21 a of the one orifice hole 21 and the long hole 22 a of the other orifice hole 22 is arranged with an interval of 180 degrees with respect to the circumferential direction of the valve body 8. These may be arranged at intervals other than 180 degrees in the circumferential direction. In this case, as a matter of course, one port 2g corresponding to one orifice hole 21 and the other port 2h corresponding to the other orifice hole 22 are also matched with the circumferential interval between the long holes 21a and 22a. The long holes 21a and 22a are arranged so as to coincide with each other in the circumferential direction.

  In the valve body 8 configured as described above, when the orifice holes 21 and 22 are opposed to the corresponding ports 2g and 2h, the notch 6c, which is a sub-passage, can be communicated with the hollow hole 2a. As a result, the upper chamber R1 and the lower chamber R2 can be in communication with each other. Further, when the ports 2g and 2h are closed with the side surfaces of the valve body 8 facing the ports 2g and 2h without the orifice holes 21 and 22 facing the ports 2g and 2h, the communication between the upper chamber R1 and the lower chamber R2 is established. Further, the flow area of the flow path formed by the ports 2g, 2h and the orifice holes 21, 22 is changed by changing the degree of overlap between the ports 2g, 2h and the orifice holes 21, 22. It can be changed. Further, when only the groove 21b (22b) is made to face the port 2g (2h) without making the long hole 21a (22a) face the port 2g (2h), the flow passage area can be made extremely small and the valve body can be made. Although the change rate of the flow path area with respect to the rotation of 8 can be reduced, whether or not to install the groove 21b (22b) is arbitrary and can be eliminated.

  Similarly, the second orifice holes 19 and 20 are opposed to the corresponding second ports 2e and 2f, respectively, so that the chamber 11 communicates with the inside of the valve body 8, and the leaf valve V3 stacked on the valve disk 9 is stacked. When one of V4 is opened, the upper chamber R1 and the lower chamber R2 are brought into communication with each other, and the side surface of the valve body 8 is made to face the second port 2e, without the second orifice holes 19 and 20 facing the second ports 2e and 2f. When the second ports 2e and 2f are closed so as to face 2f, the communication between the upper chamber R1 and the lower chamber R2 through the space 11 is blocked, and the second ports 2e and 2f By changing the overlapping degree of the second orifice holes 19 and 20, the flow area in the flow path formed by the second ports 2e and 2f and the second orifice holes 19 and 20 can be changed. Going on.

  The second orifice holes 19 and 20 are not only circular holes 19a and 20a that are longer in the circumferential direction than the long holes 21a and 22a of the orifice holes 21 and 22, but also slits 19b that are longer than the grooves 21b and 22b. Since 20b is provided, the valve element 8 is opposed to the second ports 2e and 2f with the slits 19b and 20b of the second orifice holes 19 and 20 from the state where the orifice holes 21 and 22 are directly opposed to the ports 2g and 2h, respectively. When rotating in the circumferential direction, the orifice holes 21 and 22 cannot face the ports 2g and 2h before the second orifice holes 19 and 20 can face the second ports 2e and 2f. , 2h are closed. When the orifice holes 21 and 22 face the ports 2g and 2h, that is, when the long holes 21a and 22a completely face the ports 2g and 2h, the second orifice holes 19 and 20 are circular. The holes 19a and 20a are also directly opposed to the second ports 2e and 2f, so that the flow passage area of the bypass passage 4 is maximized, and the valve body 8 is connected to the slits 19b and 20b of the second orifice holes 19 and 20 to the second ports 2e and 2f. When it is rotated in the circumferential direction so as to be opposed to each other, the flow passage area in the bypass passage 4 is gradually reduced. Finally, not only the ports 2g and 2h but also the second ports 2e and 2f As a result, the bypass passage 4 is closed because the flow passage area is zero.

  As described above, the rotary valve 5 is configured by the above-described valve body 8 and the piston rod 2 that functions as a housing with the hollow hole 2a that accommodates the valve body 8. By rotating the valve body 8, the flow passage area in the bypass passage 4 can be changed.

  When the shock absorber D expands and contracts, especially when the orifice holes 21 and 22 and the ports 2g and 2h are in direct communication with each other, the working fluid is opened and closed by the leaf valves V1 and V2. Prior to the damping passages 3a and 3b, the upper and lower chambers R1 and R2 pass back and forth through the orifice holes 21 and 22 and the ports 2g and 2h. At this time, the second orifice holes 19 and 20 are opposed to the second ports 2e and 2f, but when the expansion / contraction speed of the shock absorber D is in the low speed region, the pressure in the upper chamber R1 or the lower chamber R2 is changed to the leaf valve V3. , V4 does not reach the valve opening pressure, the expansion side passage 9a and the compression side passage 9b remain closed, and the expansion / contraction speed of the shock absorber D is in the middle / high speed range, and the pressure in the upper chamber R1 or the lower chamber R2 is Even if the opening pressure of the valves V3 and V4 is reached and the expansion side passage 9a or the pressure side passage 9b is opened, since the resistance in the leaf valves V3 and V4 is large, the working fluid is preferentially connected to the orifice holes 21 and 22 and the ports. Passes 2g and 2h and moves back and forth between the upper chamber R1 and the lower chamber R2.

  When the orifice holes 21 and 22 and the ports 2g and 2h are in communication with each other, the flow passage area of the bypass passage 4 is large and the flow passage resistance is small. The shock absorber D generates a soft damping force.

  As described above, when the orifice holes 21 and 22 and the ports 2g and 2h are in communication with each other, the area of the flow path formed by the orifice holes 21 and 22 and the ports 2g and 2h is large, and the amount of passing working fluid is large. Become more. When the shock absorber D is extended and the working fluid moves from the upper chamber R1 to the lower chamber R2, the working fluid has a large flow rate from the ports 2g and 2h to the orifice holes 21 and 22 and the valve body 8. However, the flow of the working fluid that has entered the valve body 8 through the orifice holes 21 and 22 is caused by the ports 2g and 2h and the orifice holes 21 and 22 corresponding to the ports 2g and 2h in the axial direction. Since they are arranged eccentrically, they do not collide directly in the valve body 8, and the flow of the working fluid introduced into the valve body 8 from the orifice holes 21 and 22 avoids the collision, respectively. The valve body 8 flows downward along the inner circumference of the body 8 in FIG. 1, and finally reaches the lower chamber R2.

  Therefore, in the rotary valve 5, the ports 2g and 2h and the orifice holes 21 and 22 corresponding to the ports 2g and 2h are arranged eccentrically in the axial direction, and the orifice holes 21 and 22 are directly connected to each other. Therefore, even if the flow rate of the working fluid passing through the orifice holes 21 and 22 is increased, the valve body 8 is prevented from colliding from the front in the valve body 8. There is no vortex or aeration in the interior, and the generation of abnormal noise can be suppressed.

  Subsequently, when the valve body 8 is rotated from the above state to reduce the lap area between the orifice holes 21 and 22 and the ports 2g and 2h, the working fluid becomes the orifice holes 21 and 22 and the ports 2g and 2h. Since the resistance at the time of passing through the valve is increased and it is difficult to pass through the valve, the bending rigidity of the leaf valves V3 and V4 is set to be smaller than the bending rigidity of the leaf valves V1 and V2. Is opened to move back and forth between the upper chamber R1 and the lower chamber R2 through the second orifice holes 19 and 20. The damping force can be adjusted by changing the lap area of the second orifice holes 19 and 20 and the second ports 2e and 2f. Further, when the expansion / contraction speed of the shock absorber increases, the piston 2 is finally laminated. The leaf valves V1 and V2 thus opened are opened. Also in this case, since the working fluid in the upper chamber R1 and the lower chamber R2 exchanges with each other through the second orifice holes 19 and 20, the lap area between the second orifice holes 19 and 20 and the second ports 2e and 2f is reduced. The damping force can be adjusted by changing, and the smaller the wrap area between the second orifice holes 19 and 20 and the second ports 2e and 2f, the smaller the flow path area, and the main damping passage 3a, The flow resistance in the bypass 4 that bypasses 3b increases, the damping coefficient in the shock absorber D increases, and the shock absorber D generates a hard damping force.

  Since the auxiliary passage in the bypass passage 4 of the shock absorber D is formed in the spacer 6 interposed between the partition member 7 and the piston 3 as described above, the valve body 8 in the rotary valve 5 is conventionally used. Compared with this rotary valve, at least the thickness of the leaf valve V2 and the valve stopper can be shortened in the axial direction, which reduces the manufacturing cost and is economically advantageous.

  The presence / absence and shape of the second orifice holes 19 and 20 and the second ports 2e and 2f are arbitrary, and the shapes of the orifice holes 21 and 22 and ports 2g and 2h are also arbitrary. It can be set to a suitable shape according to the attenuation characteristic.

 Although the description of the embodiment of the rotary valve is finished as described above, it is needless to say that the rotary valve of the present invention can be applied to other parts of the shock absorber without using the piston rod as a housing. . Also, the scope of the invention is not limited to the details shown or described.

1 is a partially enlarged longitudinal sectional view of a shock absorber to which a rotary valve according to an embodiment of the present invention is applied. It is a side view of the valve body of the rotary valve in one embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Piston rod 2a Hollow hole 2b in piston rod Control rod insertion hole 2c in piston rod Small diameter part 2d in piston rod Step part 2e, 2f in piston rod Second port 2g in piston rod, port 2 in piston rod 3 Piston 3a 3b Main damping passage 4 Bypass passage 5 Rotary valve 6 Spacer 6a Spacer 6b Spacer cylinder 6c Spacer notch 7 Partition member 8 Valve body 9 in rotary valve Valve disc 9a Extension side passage 9b Pressure side passage 10 Cap 10a Hole in cap 11 Chamber 12 Valve restraint 12a Tube portion 12b in valve restraint Notches 13, 14 in valve restraint Valve stopper 15 Piston nut 16 Control rod 17 Aring 18 Stopper 19, 20 Second orifice hole 19a, 20a Circular hole 19b, 20b Slit 21, 22 Orifice hole 21a, 22a Long hole 21b in orifice hole, groove 22b in orifice hole D Shock absorber R1 Upper chamber R2 Lower chamber V1, V2, V3, V4 Leaf valve

Claims (2)

A cylinder, a piston rod that is slidably inserted into the cylinder, and is slidably inserted into the cylinder and mounted on the outer periphery of the piston rod to divide the inside of the cylinder into an upper chamber and a lower chamber; A piston having a main damping passage that communicates with the chamber, and a bypass passage that bypasses the main damping passage and communicates the upper chamber and the lower chamber. The bypass passage is opened downward from the tip of the piston rod. A chamber that is formed by a hollow hole that communicates with the chamber, a partition member that is an outer periphery of the piston rod and is mounted on the upper chamber side from the piston, and that communicates with the upper chamber by a passage formed in the partition member; A sub-passage provided in the spacer interposed between the piston and the piston and communicated with the upper chamber, and a vertical direction provided in the piston rod and communicating the hollow hole and the sub-passage A cylindrical valve formed by a pair of first ports arranged eccentrically and a second port provided in the piston rod that communicates the hollow hole and the chamber, and is rotatable in the circumferential direction in the hollow hole. The valve body is provided with a pair of first orifice holes that are eccentrically arranged in the vertical direction and face the pair of first ports, respectively, and a second orifice hole that can face the second port. A rotary valve in a shock absorber . The rotary valve in the shock absorber according to claim 1, wherein the spacer is formed in a bottomed cylindrical shape, and a notch formed in the cylindrical portion is used as a sub-passage.

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