JP2010019326A - Joint device, variable damping force damper, and member joining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve workability of joining work by preventing loosening of a loosening prevention member when joining an insertion member and an insertion reception member by using the loosening prevention member. <P>SOLUTION: The joint device is provided with a parallel face 31d with a larger diameter than an inner diameter of an insertion hole 31a of a piston body 31 in an axial end of a piston rod 13, and an inclined face 31c gradually reduced in diameter from an end of the parallel face 31d and continuous with the insertion hole 31a. Since a distance d1 of the parallel face 31d and the insertion hole 31a in a radial direction is formed smaller than a radial thickness d2 of an elastic C-ring 42, when inserting the piston body 31 into the insertion hole 31a while holding the elastic C-ring 42 in a first annular groove 13d of the piston rod 13, a situation of the elastic C-ring 42 coming loose from the first annular groove 13d of the piston rod 13 and being pushed out to an exterior of the insertion hole 31a of the piston body 31 can be avoided. By this, work of joining the piston rod 13 and the piston body 31 can be easily and positively carried out. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a coupling device and a member coupling method for coupling an insertion member and a member to be inserted using a retaining member, and a variable damping force damper using the coupling device.

In Patent Document 1 below, an insertion portion 39 is formed by simultaneously engaging an elastic C-ring 56 with an engagement groove 58 formed on the outer peripheral surface of the insertion portion 39 and a holding groove 54 formed on the inner peripheral surface of the joint body 12. In the process of joining the joint body 12, the elastic C-ring 56 is formed in the opening of the joint body 12 so that the joint body 12 can be inserted by retracting into the engagement groove 58 of the insertion portion 39. A simple swivel hose joint that compresses the elastic C-ring 56 radially inward with a tapered surface 66 is described.
Japanese Patent Application Laid-Open No. 2002-295756

  By the way, in the above-mentioned conventional one, the elastic C-ring 56 held in the engagement groove 58 of the insertion portion 39 is compressed inward in the radial direction by contacting the tapered surface 66 formed in the opening of the joint body 12. When this occurs, the elastic C-ring 56 is pushed out of the engagement groove 58 in an attempt to expand with its own elasticity, and there is a problem that the workability of the connecting operation of the insertion portion 39 and the joint body 12 is poor.

  The present invention has been made in view of the above circumstances, and when joining an insertion member and a member to be inserted using a retaining member, prevents the retaining member from falling off and improves the workability of the joining work. With the goal.

  In order to achieve the above object, according to the invention described in claim 1, an insertion member, a member to be inserted in which an insertion hole into which the insertion member is inserted is formed, an outer peripheral surface of the insertion member, and the insertion member First and second annular grooves respectively provided on the inner peripheral surface of the member to be inserted, and a resilient force that expands radially outward to prevent the insertion member from coming off from the member to be inserted A joint device including an annular retaining member that simultaneously engages with the first and second annular grooves, and a parallel surface having a larger diameter than the inner diameter of the insertion hole at the axial end of the insertion hole. And an inclined surface that is gradually reduced in diameter from the end of the parallel surface and continues to the insertion hole, and the radial distance between the parallel surface and the insertion hole is greater than the radial thickness of the retaining member. A joint device is proposed which is also characterized by a small size.

  According to the invention described in claim 2, in addition to the configuration of claim 1, the first annular groove of the insertion member has a first side surface on the rear side in the insertion direction and a front side in the insertion direction of the insertion member. And a radially outer end portion of the first side surface is a rear side of the second annular groove of the inserted member in the insertion direction, with the insertion member being press-fitted into the insertion hole of the inserted member. A joint device is proposed, characterized in that the joint device is spaced rearward from the corner in the insertion direction.

  According to the invention described in claim 3, in addition to the configuration of claim 1, the first annular groove of the insertion member has a first side surface on the rear side in the insertion direction of the insertion member and a front side in the insertion direction. And a radially outer end portion of the first side surface is a rear side of the second annular groove of the inserted member in the insertion direction, with the insertion member being press-fitted into the insertion hole of the inserted member. A joint device characterized in that it is spaced radially inward from the corners on the side is proposed.

  According to the invention described in claim 4, in addition to the configuration of claim 1, the first annular groove of the insertion member includes a first side surface on the rear side in the insertion direction of the insertion member and a front side in the insertion direction. And an outer peripheral surface of the insertion member that is rearward of the insertion direction than the first side surface sandwiches a non-press-fit surface of a predetermined length continuous with the first side surface, and is further rearward of the insertion direction. A joint device is proposed which is press-fitted into the inner peripheral surface of the inserted member.

  According to the invention described in claim 5, in addition to the configuration of claim 4, the angle formed by the first side surface with the outer peripheral surface of the insertion member is set to an obtuse angle, and the non-press-fit surface is the insertion member. A joint device is proposed in which the angle formed with the outer peripheral surface of the joint is set to an obtuse angle larger than the obtuse angle.

  According to the invention described in claim 6, in addition to the configuration of any one of claims 1 to 5, the first annular groove of the insertion member is provided on the rear side in the insertion direction of the insertion member. A first side surface and a second side surface on the front side in the insertion direction, and the outer peripheral surface of the insertion member located in front of the second side surface in the insertion direction is fitted into the inner peripheral surface of the member to be inserted. A featured joint device is proposed.

  According to a seventh aspect of the present invention, there is provided a variable damping force damper using the joint device according to any one of the first to sixth aspects, wherein a magnetorheological fluid or a magnetic fluid is enclosed. A cylinder, a piston slidably fitted to the cylinder, a piston rod connected to the piston, first and second liquid chambers partitioned on both sides of the cylinder, and the cylinder A throttle that is formed to communicate the first and second liquid chambers, and a coil that is provided in the piston and that applies a magnetic force to the magnetorheological fluid or the magnetic fluid that passes through the throttle; A variable damping force damper is proposed in which an insertion member that is the piston rod and an inserted member that is the piston are coupled.

  According to the invention described in claim 8, the first annular groove provided in the outer peripheral surface of the insertion member and the inner peripheral surface of the inserted member having the insertion hole into which the insertion member is inserted. In the connecting method of the member for retaining the insertion member and the member to be inserted by simultaneously engaging the second annular groove with an annular retaining member having a resilience expanding radially outward. A first step of mounting the retaining member in the first annular groove of the insertion member, and inserting the insertion member into the insertion hole of the member to be inserted, and the retaining member at the opening of the insertion hole. A second step of reducing the diameter radially inward and retracting into the first annular groove; and further inserting the insertion member into an insertion hole of the inserted member, wherein the first annular groove of the insertion member is When the insertion member faces the second annular groove, the stopper A third step of expanding the material radially outward by its own elastic force and simultaneously engaging the first and second annular grooves, and in the second step, the opening of the insertion hole and the A member coupling method is proposed in which the radial distance from the insertion hole is smaller than the radial thickness of the retaining member.

  The piston rod 13 of the embodiment corresponds to the insertion member of the present invention, the piston 31 of the embodiment corresponds to the inserted member of the present invention, and the annular throttle 37 of the embodiment corresponds to the throttle of the present invention. The elastic C-ring 42 of the embodiment corresponds to the retaining member of the present invention, and the chamfer c of the embodiment corresponds to the non-press-fit surface of the present invention.

  According to the configuration of claim 1, the parallel surface having a diameter larger than the inner diameter of the insertion hole and the diameter of the insertion surface are gradually reduced from the end of the parallel surface to the insertion hole. Since the radial distance between the parallel surface and the insertion hole is smaller than the radial thickness of the retaining member, the retaining member is held in the first annular groove of the retaining member. When inserting into the insertion hole of the insertion member, it is possible to avoid a situation in which the retaining member is dropped from the first annular groove of the insertion member and pushed out of the insertion hole. Thereby, the operation | work which couple | bonds an insertion member and a to-be-inserted member by engaging a retaining member with both the 1st annular groove of an insertion member and the 2nd to-be-inserted member of an insertion member can be performed easily and reliably.

  According to the configuration of claim 2, the first annular groove of the insertion member includes the first side surface on the rear side in the insertion direction of the insertion member and the second side surface on the front side in the insertion direction, and the insertion member is the member to be inserted. In the state of being press-fitted into the insertion hole, the radially outer end portion of the first side surface is spaced apart on the rear side in the insertion direction with respect to the corner portion on the rear side in the insertion direction of the second annular groove of the inserted member. The press-fitting load of the insertion member prevents the second annular groove from being deformed at the corner on the rear side in the insertion direction, and the first and second annular grooves are opposed to each other with the first and second annular grooves facing each other with high accuracy. Can be reliably engaged.

  According to the configuration of claim 3, the first annular groove of the insertion member includes the first side surface on the rear side in the insertion direction of the insertion member and the second side surface on the front side in the insertion direction, and the insertion member is the member to be inserted. Since the radially outer end of the first side surface is spaced radially inward from the corner on the rear side in the insertion direction of the second annular groove of the member to be inserted, the insertion member is press-fitted. The load is prevented from deforming the corner on the rear side in the insertion direction of the second annular groove, and the first and second annular grooves are opposed to each other with high accuracy and the retaining member is securely engaged with the first and second annular grooves. Can be combined.

  According to the configuration of claim 4, the first annular groove of the insertion member includes the first side surface on the rear side in the insertion direction of the insertion member and the second side surface on the front side in the insertion direction, and is inserted more than the first side surface. When the outer peripheral surface of the insertion member at the rear side in the direction is press-fitted into the inner peripheral surface of the member to be inserted, the second annular groove of the member to be inserted is provided because the non-pressing surface having a predetermined length connected to the first side surface is provided. Can be prevented from being deformed by the press-fitting load, and the first and second annular grooves can be opposed to each other with high precision, and the retaining members can be reliably engaged with the first and second annular grooves.

  According to the configuration of claim 5, the angle formed by the first side surface with the outer peripheral surface of the insertion member is set as an obtuse angle, and the angle formed by the non-press-fit surface with the outer peripheral surface of the insertion member is set at an obtuse angle larger than the obtuse angle. Therefore, it is possible to easily form the non-press-fit surface while ensuring the operational effect of the configuration of the second aspect.

  According to the configuration of the sixth aspect, the first annular groove of the insertion member includes the first side surface on the rear side in the insertion direction and the second side surface on the front side in the insertion direction, and is further forward in the insertion direction than the second side surface. Since the outer peripheral surface of the insertion member is fitted into the inner peripheral surface of the member to be inserted, the second annular groove of the member to be inserted is not deformed when the insertion member is inserted into the insertion hole of the member to be inserted. The retaining members can be reliably engaged with the first and second annular grooves by accurately opposing the first and second annular grooves.

  According to the seventh aspect of the present invention, a cylinder enclosing a magnetorheological fluid or a magnetic fluid, a piston slidably fitted in the cylinder, a piston rod connected to the piston, and both sides of the cylinder sandwiching the piston The divided first and second liquid chambers, a throttle formed in the cylinder to communicate the first and second liquid chambers, and a magnetic viscous fluid or magnetic fluid that is provided in the piston and passes through the throttle are made to act on the magnetic force. In a variable damping force damper including a coil, an operation of coupling a piston and a piston rod with a joint device can be performed efficiently and reliably.

  According to the invention described in claim 8, in order to prevent the insertion member and the member to be inserted with the retaining member, the retaining member is attached to the first annular groove of the insertion member in the first step. While inserting the insertion member into the insertion hole of the member to be inserted in two steps, the retaining member is radially reduced inward in the opening portion of the insertion hole and retracted into the first annular groove. When the insertion member is further inserted into the insertion hole of the member to be inserted and the first annular groove of the insertion member faces the second annular groove of the member to be inserted, the retaining member is moved radially outward by its own elastic force. The diameter is expanded and simultaneously engaged with the first and second annular grooves. Since the radial distance between the opening of the insertion hole and the insertion hole is made smaller than the radial thickness of the retaining member, the retaining member is dropped from the first annular groove of the inserting member in the second step. The situation of being pushed out from the insertion hole of the member to be inserted can be avoided, and the workability of the connecting operation of the insertion member and the member to be inserted can be improved.

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

  1 to 9 show a first embodiment of the present invention. FIG. 1 is a longitudinal sectional view of a variable damping force damper, FIG. 2 is an enlarged view of part 2 of FIG. 1, and FIG. 4 is an enlarged view of 4 parts of FIG. 1, FIG. 5 is a sectional view around the piston of the variable damping force damper, FIG. 6 is an explanatory view of the action when the piston is assembled, and FIG. 7 is 7 part of FIG. FIG. 8 is an enlarged view of a portion 8 in FIG. 4, and FIG. 9 is an explanatory view of the operation of the seal member.

  As shown in FIG. 1, a variable damping force damper D used in a vehicle suspension device is connected to a suspension arm (not shown) through a rubber bush joint 11 and an open cylinder 12 and a vehicle body (not shown). And a piston rod 13 fitted to the cylinder 12. A piston 14 slidably fitted to the inner peripheral surface of the cylinder 12 is fixed to the tip of the piston rod 13, and the first liquid chamber 15 and the second liquid chamber 16 are defined on both sides in the axis L direction of the piston 14. Is done. Magneto-rheological fluids (MRF: Magneto-Rheological Fluids) are sealed in the first and second liquid chambers 15 and 16. A magnetorheological fluid is a fluid in which micro-scale iron particles are mixed, and has a property that the viscosity changes when magnetism acts. A free piston 17 is slidably fitted between the first liquid chamber 15 and the closed end of the cylinder 12 via a seal member 18, and high-pressure gas flows on the side of the free piston 17 opposite to the first liquid chamber 15. The sealed gas chamber 19 is partitioned.

  The open end of the cylinder 13 on the second liquid chamber 16 side is closed by a piston rod guide 20, and the piston rod 13 is slidably fitted into a guide hole 20 a formed in the piston rod guide 20. A stopper 21 made of an elastic material is fixed to the piston rod 13 located in the second liquid chamber 16, and the stopper 21 abuts on the piston rod guide 20, thereby restricting the extension end of the piston rod 13 from the cylinder 12. Is done.

  As apparent from FIG. 2, the piston rod guide 20 is fitted to the inner peripheral surface of the open end of the cylinder 12, and the holder 22 fitted to the outer peripheral surface of the open end of the cylinder 12 is connected to the cylinder 12 and the piston rod guide. It is fixed by caulking 23 together with 20. A stopper abutting plate 24 with which the stopper 21 abuts is fixed to the end of the piston rod guide 20 facing the second liquid chamber 16. A protection plate 25 that protects the portion is fixed to the holder 22 that wraps around the end of the cylinder 12.

  A seal member 26 that seals between the inner peripheral surface of the cylinder 12 and the seal groove 20 b formed on the outer peripheral surface of the piston rod guide 20 is mounted. Further, a seal member 28 that prevents liquid leakage from the second liquid chamber 16 side is attached to a seal groove 20c that is open at one end and formed on the inner peripheral surface of the piston rod guide 20 on the second liquid chamber 16 side. A seal member 29 that prevents dust from entering the second liquid chamber 16 is attached to a seal groove 20 d that is open at one end formed on the inner peripheral surface of the guide 20 on the side opposite to the second liquid chamber 16.

  FIG. 3 shows the sectional shape of the seal member 28 mounted in the seal groove 20b on the inner peripheral surface of the piston rod guide 20 on the second liquid chamber 16 side in the free state (the axis L of the cylinder 12 and the piston rod 13 is shown). A longitudinal sectional shape cut by a plane passing through) is shown. In the drawing, the upper side is the radially outer side with respect to the axis L, and the lower side is the radially inner side with respect to the axis L.

  The seal member 28 made of nitrile rubber has an outer peripheral surface 28a that contacts the bottom portion 20e of the seal groove 20b and an end surface 28b that contacts the step portion 20f of the seal groove 20b, and is opposite to the outer peripheral surface 28a. An annular lip 28c having a triangular cross section protruding radially inward is formed, and an annular U groove 28d recessed in a U shape in the direction of the axis L is formed on the opposite side of the end face 28b. The lip 28c is provided with a tip A that protrudes most inward in the radial direction and two bases B and C on both sides in the axis L direction. The position of the base B on the end face 20b side is the guide of the piston rod guide 20 The distance d0 enters the outer side in the radial direction with respect to the hole 20a. Accordingly, an annular space 30 (a portion shown by shading) is formed in the vicinity of the base B of the lip 28c with respect to a line obtained by extending the guide hole 20a of the piston rod guide 20 in the axis L direction.

  In a state where the piston rod 13 is inserted through the guide hole 20a of the piston rod guide 20, the lip 28c of the seal member 28 is compressed radially outward and is brought into close contact with the outer peripheral surface of the piston rod 13, and as shown in FIG. Demonstrate.

  As shown in FIGS. 4 and 5, the piston 14 has a thick cylindrical piston main body 31 in which the insertion hole 31 a is fitted to the small diameter portion 13 a at the tip of the piston rod 13, and the small diameter portion 13 a of the piston rod 13. A washer 32 that contacts the stepped portion 13b, a disc-shaped first side cover 34 fixed to one end face of the piston body 31 with bolts 33, and the other end face of the washer 32 and the piston body 31. A disc-shaped second side cover 35 and an outer ring 36 fitted to the outer periphery of the piston body 31 and supported by the first and second side covers 34 and 35 at both ends in the axis L direction.

  The first side cover 34 has a plurality of (four in the embodiment) arcuate openings 34a arranged along the outer periphery thereof. The second side cover 35 has a plurality of arc-shaped (four in the embodiment) openings 35a arranged along the outer peripheral portion thereof, and a center that fits with the outer periphery of the piston rod 13 with a gap. And a hole 35b. An annular throttle 37 is formed between the outer peripheral surface of the piston body 31 and the inner peripheral surface of the outer ring 36, and one end of the annular throttle 37 passes through the opening 34 a of the first side cover 34 to form the first liquid chamber. 15, and the other end of the annular throttle 37 communicates with the second liquid chamber 16 through the openings 35 a of the second side cover 35.

  A coil support groove 31b is formed on the outer peripheral surface of the piston body 31 facing the inner peripheral surface of the annular throttle 37, and the resin member 39 in which the coil 38 is embedded is held so as to be fitted in the coil support groove 31b. A harness guide portion 39a extending radially inward from the resin member 39 is fitted to the tip of the piston rod 13 via a seal member 40, and a harness 41 extending from the coil 38 is connected to the inside of the harness guide portion 39a and the piston. The rod 13 is guided to the outside through the shaft hole 13c penetrating the center of the rod 13 along the axis L.

  A partial conical inclined surface 31c and a cylindrical parallel surface 31d are connected to the end of the insertion hole 31a of the piston body 31 on the second side cover 35 side, and the parallel surface 31c is the second side cover 35. Opposite the central hole 35b.

  As shown in an enlarged view in FIG. 8, an annular second annular groove 31e is formed on the inner circumferential surface of the insertion hole 31a of the piston body 31, and an annular outer circumferential surface of the piston rod 13 that faces the second annular groove 31e. The first annular groove 13d is formed. Then, an elastic C-ring 42 having a cut at one place in the circumferential direction is fitted so as to straddle the second annular groove 31e and the first annular groove 13d.

  The cross-sectional shape of the second annular groove 31e of the piston body 31 is a quadrangle with rounded bottom corners. However, as shown in FIG. 7, the cross-sectional shape of the first annular groove 13d of the piston rod 13 is the piston rod on the other end side. 13 has a first wall surface a that forms an obtuse angle α with respect to the outer peripheral surface of the piston 13, while a second wall surface b that is perpendicular to the outer peripheral surface of the piston rod 13 has one end thereof. Furthermore, a non-press-fit surface c that gradually increases in diameter and continues to the outer peripheral surface of the piston rod 13 is formed at the radially outer end of the first wall surface a of the first annular groove 13d.

  Next, the operation of the embodiment of the present invention having the above configuration will be described.

  First, an operation when the piston 14 is assembled to the piston rod 13 will be described.

  The washer 32 is fitted to the small diameter portion 13 a of the piston rod 13 and brought into contact with the stepped portion 13 b, the elastic C ring 42 is fitted to the first annular groove 13 d of the piston rod 13, and a seal member is attached to the tip of the piston rod 13. The piston rod 13 in this state is inserted into the insertion hole 31a of the piston body 31 of the piston 14 assembled in advance as a subassembly (see FIG. 6).

  Since the distal end portion of the piston rod 13, that is, the distal end portion 13d '(see FIG. 7) closer to the distal end than the first annular groove 13d has a smaller diameter than the small diameter portion 13a, the distal end portion 13d' It can be easily inserted into the insertion hole 31a of the 31 by a clearance fit. In the process, when the elastic C-ring 42 locked in the first annular groove 13d of the piston rod 13 reaches the opening end of the parallel surface 31d of the piston body 31, the elastic C-ring 42 is brought into contact with the parallel surface 31d to be reduced in diameter. It is squeezed inward in the direction and securely fits inside the parallel surface 31d. When the piston rod 13 is further inserted, the elastic C-ring 42 is guided by the inclined surface 31c connected to the parallel surface 31d and is further compressed inward in the radial direction, and is inserted into the first annular groove 13d of the piston rod 13 inside. Fully stowed. As a result, the piston rod 13 can be inserted into the insertion hole 31 a of the piston body 31 without being obstructed by the elastic C ring 42.

  Since the outer diameter of the small diameter portion 13a of the piston rod 13 is slightly larger than the inner diameter of the insertion hole 31a of the piston main body 31, the piston rod 13 is inserted into the insertion hole 31a by press fitting. At this time, the press-fitting can be performed smoothly by the action of the non-press-fitting surface c (see FIG. 7) connected to the first annular groove 13d of the piston rod 13.

  As shown in FIG. 7, if it is assumed that the inclined surface 31c of the piston body 31 extends to the end surface of the piston body 31 and there is no parallel surface 31d, the elasticity that tends to expand radially outward by its own elasticity. There is a possibility that the C-ring 42 falls out of the first annular groove 13d of the piston rod 13 and is pushed out of the piston main body 31 during the press-fitting process. However, according to the present embodiment, the elastic C ring 42 is compressed radially inward by the opening of the parallel surface 31d and held in the first annular groove 13d of the piston rod 13, so that the elastic C ring 42 is It is inserted into the insertion hole 31a of the piston body 31 without dropping from the first annular groove 13d.

  When the piston rod 13 is further press-fitted, the elastic C ring 42 expands by its own elasticity at the moment when the first annular groove 13d of the piston rod 13 coincides with the second annular groove 31e of the piston body 31, and the piston body 31 It fits in the second annular groove 31e (see FIG. 8). In this state, since the diameter of the elastic C-ring 42 is larger than the depth of the second annular groove 31e of the piston body 31, the elastic C-ring 42 has the second annular groove 31e of the piston body 31 and the first annular groove of the piston rod 13. The piston rod 13 is engaged with the piston main body 31 so that it cannot be pulled out.

  Further, in the press-fitting process of the piston rod 13, the tip end portion 13d '(see FIG. 7) of the piston rod 13 has a slightly small diameter and is fitted into the insertion hole 31a of the piston main body 31, so that the piston main body 31 is pressed by the press-fitting load. The second annular groove 31e is prevented from being deformed. Accordingly, the first annular groove 13d of the piston rod 13 and the second annular groove 31e of the piston body 31 can be opposed to each other with high accuracy, and the elastic C ring 42 can be reliably engaged therewith.

  Further, when the first annular groove 13d of the piston rod 13 faces the second annular groove 31e of the piston body 31 in the final stage of press-fitting, the piston body 31 is inserted on the rear side in the press-fitting direction of the first annular groove 13d of the piston rod 13. By providing the non-press-fit surface c smaller in diameter than the hole 31a, the outer peripheral surface of the piston rod 13 is prevented from deforming the corner on the rear side in the press-fit direction of the second annular groove 31e of the piston body 31. Can do. Accordingly, the first annular groove 13d of the piston rod 13 and the second annular groove 31e of the piston body 31 can be opposed to each other with high accuracy, and the elastic C ring 42 can be reliably engaged therewith.

  Next, the operation of the variable damping force damper D will be described.

  When the piston rod 13 is pushed into the cylinder 12 by the bumps of the suspension, the magnetoviscous fluid in the first liquid chamber 15 whose volume has been reduced becomes the opening 34a ... of the first side plate 34 of the piston 14, the annular throttle 37, and the second Through the openings 35a of the side plate 35, it flows into the second liquid chamber 16, and at that time, a damping force is generated by the flow resistance through which the magnetorheological fluid passes through the annular throttle 37. The increase in the volume of the piston rod 13 that has entered the first and second liquid chambers 15 and 16 is compensated by the decrease in the volume of the gas chamber 19 due to the advance of the free piston 17.

  When the piston rod 13 is pulled out from the inside of the cylinder 12 due to rebound of the suspension, the magneto-rheological fluid in the second liquid chamber 16 whose volume has been reduced becomes the opening 35a of the second side plate 35 of the piston 14,. Passing through the openings 34 a of the side plate 34 and flowing into the first liquid chamber 15, a damping force is generated by the flow resistance through which the magnetorheological fluid passes through the annular throttle 37. The decrease in the volume of the piston rod 13 that has escaped from the first and second liquid chambers 15 and 16 is compensated by the increase in the volume of the gas chamber 19 due to the retraction of the free piston 17.

  When the amount of energization to the coil 38 inside the piston 14 is increased when the magnetorheological fluid passes through the annular restrictor 37, the generated magnetic field becomes stronger, so that the viscosity of the magnetorheological fluid increases and passes through the annular restrictor 37. And the damping force increases. Conversely, if the amount of current supplied to the coil 38 inside the piston 14 is reduced, the generated magnetic field becomes weak, so that the viscosity of the magnetorheological fluid becomes low and easily passes through the annular throttle 37, and the damping force decreases. . Therefore, the damping force of the variable damping force damper D can be arbitrarily controlled by changing the energization amount to the coil 38.

  Next, the operation of the seal member 28 provided on the piston rod guide 20 will be described.

  In order to prevent the cavitation phenomenon from occurring in the magnetorheological fluid sealed in the first and second liquid chambers 15 and 16 when the piston 14 moves at a high speed inside the cylinder 12, high-pressure gas is introduced into the gas chamber 19. By encapsulating, high pressure is applied to the magnetorheological fluid. Therefore, the sealing member 28 provided in the piston rod guide 20 is required to have high sealing performance that prevents leakage of the magnetorheological fluid while suppressing an increase in frictional force.

  As shown in FIG. 3, the annular lip 28 c of the seal member 28 includes a distal end portion A that protrudes most inward in the radial direction and two base portions B and C on both sides in the axis L direction. An annular space 30 is formed when the position enters the radially outer side with respect to the inner peripheral surface of the piston rod guide 20 by a distance d0.

  9A shows a state in which the seal member 28 is in a free state, FIG. 9B shows a case in which the lip 28c of the seal member 28 is weakly pressed against the outer peripheral surface of the piston rod 13, and FIG. 28 shows a state in which the lip 28c of 28 is strongly pressed against the outer peripheral surface of the piston rod 13. As described above, when the lateral force (radial force) of the piston rod 13 increases, the amount of compression of the lip 28c of the seal member 28 gradually increases. Since the surface pressure at which the lip 28c is pressed against the outer peripheral surface of the piston rod 13 is proportional to the compression amount of the lip 28c, the surface pressure is insufficient unless the compression amount is sufficiently secured, and the magnetorheological fluid passes through the lip 28c. There is a possibility of leakage. At this time, when the contact area between the outer peripheral surface of the lip 28c and the piston rod 13 becomes excessive because the compression amount of the lip 28c is increased to increase the surface pressure, the frictional resistance increases and the piston rod 13 smoothly slides. May be hindered.

  According to the present embodiment, since the lip 28c has a triangular cross section, even if the compression amount of the lip 28c is increased to ensure a sufficient surface pressure, the contact area is prevented from becoming excessive, and the sealing property is prevented. And low friction can be achieved. If the lip of the sealing member 28 has a quadrangular cross section, the contact area becomes larger than that of the lip 28c having a triangular cross section, and the frictional force increases even if the compression amount of the lip 28c is the same.

  In order to reduce the frictional force, the width in the direction of the axis L of the lip having a quadrangular cross section may be reduced. However, in this case, the lip collapses as the piston rod 13 slides, and the sealing performance is lost. There is a problem. On the other hand, in the present embodiment, since the lip 28c has a triangular cross section, the width in the axis L direction on the bases B and C side is large even if the width in the axis L direction near the tip end A is small. Therefore, it is possible to reliably prevent the lip 28c from falling.

  As shown in FIG. 9C, when a strong lateral force acts on the piston rod 13 and the lip 28 c is greatly compressed, a space 30 is formed between the lip 28 c and the step portion 20 f of the piston rod guide 20. Therefore, the pressure of the lip 28c pressed against the outer peripheral surface of the piston rod 13 can be prevented from excessively increasing due to the meat of the lip 28c of the seal member 28 being pushed into the space 30. It is possible to suppress an increase in the frictional force of the moving part. If the space 30 does not exist, there is no escape space for the meat of the lip 28c when the seal member 28 is strongly compressed. Therefore, the surface pressure at which the lip 28c is brought into pressure contact with the outer peripheral surface of the piston rod 13 is excessively increased. The frictional force of the moving part increases rapidly.

  As described above, according to the present embodiment, by devising the shape of the lip 28c of the sealing member 28, the surface area of the contact surface can be reduced while ensuring the surface pressure of the contact surface and preventing leakage of the magnetorheological fluid. It is possible to suppress the sliding resistance of the piston rod 13 to a minimum. In particular, since the magnetorheological fluid contains iron particles, if the iron particles enter between the lip 28c and the outer peripheral surface of the piston rod 13, problems such as premature wear of the piston rod 13 occur. Since the surface pressure of the contact surface of the lip 28c can be ensured, it is possible to effectively prevent the iron particles from entering the sliding surface.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the second embodiment, an annular protrusion 28e extending inward in the radial direction is formed on the side of the seal member 28 that contacts the step 20f of the piston rod guide 20. The position of the inner peripheral surface of the annular protrusion 28e coincides with the guide hole 20a of the piston rod guide 20, is located radially inward from the outer peripheral surface of the space 30, and radially outward from the tip A of the lip 28c. is there.

  Accordingly, when the lip 28c of the seal member 28 is compressed by the outer peripheral surface of the piston rod 13, the annular protrusion 28e acts as a stopper to suppress the deformation of the lip 28c, so that the surface pressure of the contact surface of the lip 28c is increased. Sealing performance can be ensured.

  Next, a third embodiment of the present invention will be described with reference to FIG.

  In the third embodiment, an annular backup ring 43 made of Teflon (registered trademark) or the like that is harder than the seal member 28 and has a smaller friction coefficient between the seal member 28 and the step portion 20f of the piston rod guide 20 is used. Is the one that is attached. The position of the inner peripheral surface of the backup ring 43 is radially inward from the guide hole 20a of the piston rod guide 20, and is radially outward from the tip A of the lip 28c. The space 30 of the seal member 28 is formed between the lip 28 c and the backup ring 43.

  Therefore, when the lip 28c of the seal member 28 is strongly compressed by the outer peripheral surface of the piston rod 13, the inner peripheral surface of the backup ring 43 contacts the outer peripheral surface of the piston rod 13 and prevents excessive compression of the lip 28c. Thus, it is possible to prevent a sudden increase in the frictional force between the lip 28c and the outer peripheral surface of the piston rod 13.

  Next, a fourth embodiment of the present invention will be described with reference to FIG.

  In the fourth embodiment, the first wall surface a of the first annular groove 13d of the piston rod 13 extends further to the rear than the rear end of the second annular groove 31e of the piston main body 31. The non-press-fit surface c (see FIG. 8) of the form is omitted.

  According to the shape of the first wall surface a of the fourth embodiment, the same effect as the non-press-fit surface c of the first embodiment is achieved, and the outer peripheral surface of the piston rod 13 is the first of the piston body 31. It is possible to prevent the corner portion on the rear side in the press-fitting direction of the two annular grooves 31e from being deformed.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention can perform a various design change in the range which does not deviate from the summary.

  For example, the use of the joint device of the present invention is not limited to the variable damping force damper D of the embodiment.

  The variable damping force damper D of the embodiment uses a magnetorheological fluid, but the same effect can be obtained by using a magnetorheological fluid (a fluid mixed with nanoscale magnetic metal fine particles) instead of the magnetorheological fluid. Can be achieved.

  Further, the number and shape of the openings 34a,..., 35a... Of the first and second side covers 34, 35 are not limited to those of the embodiment, and instead of the single annular diaphragm 37, they are arranged in the circumferential direction. A plurality of spaced apertures may be provided.

1 is a longitudinal sectional view of a variable damping force damper according to a first embodiment. 2 enlarged view of FIG. Part 3 enlarged view of FIG. 4 enlarged view of FIG. Sectional view around the piston of the variable damping force damper Action diagram when assembling the piston 7 enlarged view of FIG. 8 enlarged view of FIG. Action diagram of the seal member The figure corresponding to the said FIG. 3 based on 2nd Embodiment. The figure corresponding to the said FIG. 3 based on 3rd Embodiment. The figure corresponding to the said FIG. 8 based on 4th Embodiment.

Explanation of symbols

12 Cylinder 13 Piston rod (insertion member)
13d First annular groove 14 Piston 15 First liquid chamber 16 Second liquid chamber 31 Piston (member to be inserted)
31a Insertion hole 31c Inclined surface 31d Parallel surface 31e Second annular groove 37 Annular aperture (aperture)
38 Coil 42 Elastic C-ring (Retaining member)
L axis a first side b second side c chamfer (non-press-fit surface)
d1 Radial distance between parallel surface and insertion hole d2 Radial thickness α of retaining member Angle formed by first side surface and outer peripheral surface of insertion member β Angle formed by non-press-fit surface and outer peripheral surface of insertion member

Claims (8)

The inserted member (13), the inserted member (31) in which the insertion hole (31a) into which the inserted member (13) is inserted, the outer peripheral surface of the inserted member (13) and the inserted member (31) ) And the first and second annular grooves (13 d, 31 e) provided on the inner peripheral surface of each of the inner peripheral surface and the insertion member (13) on the outer side in the radial direction to prevent the insertion member (13) from coming off from the insertion target member (31). A joint device comprising: an annular retaining member (42) having an elastic force to expand and simultaneously engaging the first and second annular grooves (13d, 31e);
At the end of the insertion hole (31a) in the axis (L) direction, the parallel surface (31d) having a diameter larger than the inner diameter of the insertion hole (31a) and the end of the parallel surface (31d) are gradually reduced. An inclined surface (31c) that is continuous with the insertion hole (31a) and is provided,
A joint device characterized in that a radial distance (d1) between the parallel surface (31d) and the insertion hole (31a) is smaller than a radial thickness (d2) of the retaining member (42).   The first annular groove (13d) of the insertion member (13) includes a first side surface (a) on the rear side in the insertion direction of the insertion member (13) and a second side surface (b) on the front side in the insertion direction. In a state where the insertion member (13) is press-fitted into the insertion hole (31a) of the member to be inserted (31), the radially outer end of the first side surface (a) is the first part of the member to be inserted (31). The joint device according to claim 1, characterized in that the two annular grooves (31e) are spaced rearward in the insertion direction with respect to corners on the rearward side in the insertion direction.   The first annular groove (13d) of the insertion member (13) includes a first side surface (a) on the rear side in the insertion direction of the insertion member (13) and a second side surface (b) on the front side in the insertion direction. In a state where the insertion member (13) is press-fitted into the insertion hole (31a) of the member to be inserted (31), the radially outer end of the first side surface (a) is the first part of the member to be inserted (31). 2. The joint device according to claim 1, wherein the joint device is spaced radially inward from a corner on the rear side in the insertion direction of the two annular grooves (31 e).   The first annular groove (13d) of the insertion member (13) includes a first side surface (a) on the rear side in the insertion direction of the insertion member (13) and a second side surface (b) on the front side in the insertion direction. The outer peripheral surface of the insertion member (13) behind the first side surface (a) in the insertion direction sandwiches a non-press-fit surface (c) having a predetermined length continuous with the first side surface (a). 2. The joint device according to claim 1, wherein the joint device is press-fitted into an inner peripheral surface of the member to be inserted (31) rearward in the insertion direction.   The angle (α) formed by the first side surface (a) with the outer peripheral surface of the insertion member (13) is set to an obtuse angle, and the angle (c) formed by the non-press-fit surface (c) with the outer peripheral surface of the insertion member (13) ( The joint device according to claim 4, wherein β) is set to an obtuse angle larger than the obtuse angle.   The first annular groove (13d) of the insertion member (13) includes a first side surface (a) on the rear side in the insertion direction of the insertion member (13) and a second side surface (b) on the front side in the insertion direction. The outer peripheral surface of the insertion member (13) ahead of the second side surface (b) in the insertion direction is fitted into the inner peripheral surface of the inserted member (31) with a gap. The joint device according to any one of claims 5 to 6. A variable damping force damper using the joint device according to any one of claims 1 to 6, wherein a cylinder (12) enclosing a magnetorheological fluid or a magnetic fluid, and the cylinder (12) A piston (14) that is slidably fitted, a piston rod (13) connected to the piston (14), and a first section defined on both sides of the piston (14) of the cylinder (12), A second liquid chamber (15, 16), a throttle (37) formed in the cylinder (14) to communicate the first and second liquid chambers (15, 16), and the piston (14). A coil (38) for applying a magnetic force to the magnetic viscous fluid or the magnetic fluid passing through the throttle (37),
The variable damping force damper, wherein the joint device couples an insertion member that is the piston rod (13) and an inserted member that is the piston (14). A first annular groove (13d) provided on the outer peripheral surface of the insertion member (13) and an inner peripheral surface of the inserted member (31) having an insertion hole (31a) into which the insertion member (13) is inserted. By simultaneously engaging an annular retaining member (42) having a resilient force that expands radially outward in the provided second annular groove (31e), the insertion member (13) and the covered member In the method of connecting the members that prevent the insertion member (31) from coming off,
A first step of mounting the retaining member (42) in the first annular groove (13d) of the insertion member (13);
While the insertion member (13) is inserted into the insertion hole (31a) of the inserted member (31), the retaining member (42) is reduced in diameter radially inward at the opening of the insertion hole (31a). A second step of retracting into the first annular groove (13d),
The insertion member (13) is further inserted into the insertion hole (31a) of the inserted member (31), and the first annular groove (13d) of the insertion member (13) is the second of the inserted member (31). When facing the annular groove (31e), the retaining member (42) is expanded radially outward by its own elastic force and simultaneously engaged with the first and second annular grooves (13d, 31e). And a third step of
In the second step, the radial distance (d1) between the opening of the insertion hole (31a) and the insertion hole (31a) is larger than the radial thickness (d2) of the retaining member (42). A method for joining members characterized by being small.

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