JP2012197879A - Shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shock absorber which is low-cost, allows a small solenoid to be used therefor, and allows damping force adjustment to be performed actively.SOLUTION: As a means for solving the problem, the shock absorber includes: a shock absorber body D which includes a cylinder 2, a piston 3 slidably inserted within the cylinder 2 to partition the inside of the cylinder 2 into a pressure side chamber R2 filled with liquid and an extension side chamber R1, and a piston rod 4 inserted within the cylinder 2 to be connected to the piston 3 and which is mounted between a vehicle body and an axle of a saddle riding vehicle; a flow path 5 permitting passage of fluid in one or both of extension time and contraction time of the shock absorber body D; and a damping force regulation mechanism V provided in a midway portion of the flow path 5 to regulate damping force generated by the shock absorber body D. Therein, the damping force regulating mechanism V includes a spool valve 7 and a solenoid 8, and the spool valve 7 includes a spool valve body 21 formed of a synthetic resin material and a magnetic member 22 formed integrally with the spool valve body 21 to serve as a movable iron core of the solenoid 8.

Description

  The present invention relates to an improved shock absorber.

  Conventionally, as a shock absorber, for example, there is a front fork of a two-wheeled vehicle, and in such a shock absorber, a damping force of a shock absorber body incorporated therein can be adjusted.

  Specifically, a cylinder connected to the outer tube, a piston that is slidably inserted into the cylinder and divides the inside of the cylinder into a compression side chamber and an extension side chamber, and one end that is inserted into the cylinder and has the outer tube A shock absorber body having a piston rod connected to an inner tube slidably inserted into the piston and having the other end connected to the piston, a passage communicating with the compression side chamber and the extension side chamber of the shock absorber body, A check valve that is provided in the middle of the passage and allows only a flow from the compression side chamber to the expansion side chamber, or conversely, only a flow from the extension side chamber to the compression side chamber, a needle valve provided in the middle of the passage, and a piston Some include a stepping motor that is fixed to the other end of the rod and drives a needle valve (see, for example, Patent Document 1).

  In this shock absorber, when it is extended, the piston valve provided on the piston resists the flow of hydraulic oil and exerts a damping force. When contracted, the base valve provided at the end of the cylinder causes the base valve to flow out from the cylinder to the reservoir. In addition to this, the damping force is exerted by giving resistance to the oil flow. In addition to this, the damping force generated by the shock absorber is adjusted by driving the needle valve and adjusting the flow resistance in the needle valve. Can be variable.

JP 2008-14431 A

  According to the shock absorber described above, since the stepping motor is used to drive the needle valve, it takes time to change the valve opening, and the damping force of the front fork is adjusted by active control such as skyhook control. Even if trying to do so, the response of the damping force adjustment is not in time, and it is difficult to implement the above control.

  In the shock absorber, a solenoid can be used to improve the response of the damping force adjustment. However, vertical vibrations are constantly input to the shock absorber during traveling of the vehicle, and particularly when traveling on rough roads, acceleration acting on the shock absorber is large. When attempting to drive a valve that actually makes the damping force variable in the axial direction with a solenoid, the movable part of the valve or solenoid is elastically supported only in the axial direction and is not fixedly supported. However, if the valve operates greatly, the opening degree of the valve changes, and there is a problem that the targeted damping force cannot be exhibited.

  Accordingly, the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a shock absorber capable of actively performing damping force adjustment while exhibiting stable damping force. That is.

  In order to achieve the above-mentioned object, the problem-solving means of the present invention includes a cylinder, a piston that is slidably inserted into the cylinder, and that divides the cylinder into a pressure side chamber and an extension side chamber, and a cylinder A shock absorber body including a piston rod inserted into the piston and coupled to the piston, a flow path that allows liquid to pass when the shock absorber body is extended or contracted, and a middle of the flow path The damping force adjusting mechanism includes a spool valve provided in the flow path, and the spool valve using the spool valve as a movable iron core. A solenoid that is driven in the flow path, and the spool valve is integrated with the spool valve main body formed of a synthetic resin material, and functions as a movable iron core of the solenoid. Characterized by comprising a magnetic member that.

  In the shock absorber of the present invention, the spool valve is composed of a magnetic member functioning as a movable iron core and a spool valve body formed of a synthetic resin material having a specific gravity smaller than that of the magnetic member, and the entire spool valve is composed of a magnetic member. Compared to the above, the overall weight of the spool valve, which is a movable part in the damping force adjusting mechanism, is reduced. As a result, the inertial force acting on the spool valve due to the large acceleration in the expansion / contraction direction that is input to the shock absorber while the vehicle is traveling can be reduced, and vibration of the spool valve can be suppressed. It is possible to prevent the generated damping force from changing vibrationally without becoming the targeted damping force. In other words, a stable damping force can be exhibited while using the solenoid. In other words, the solenoid can be used for the shock absorber, and the responsiveness for adjusting the damping force of the shock absorber can be dramatically improved. .

  According to the shock absorber of the present invention, it is possible to perform damping force adjustment by active control such as skyhook control while exhibiting stable damping force.

It is sectional drawing of the buffer in one Embodiment. It is an expanded sectional view of the damping force adjustment mechanism in one embodiment.

  The present invention will be described below based on the embodiments shown in the drawings. As shown in FIG. 1, the shock absorber 1 according to the embodiment includes a cylinder 2, an extension side chamber R <b> 1 that is slidably inserted into the cylinder 2, and is filled with a liquid such as hydraulic oil, and the compression side. A shock absorber body D having a piston 3 partitioned into a chamber R2 and a piston rod 4 inserted into the cylinder 2 and connected to the piston 3, and allows passage of liquid only when the shock absorber body D is extended. And a damping force adjusting mechanism V that is provided in the middle of the channel 5 and adjusts the damping force generated by the shock absorber 1.

  Hereinafter, each part of the shock absorber 1 will be described in detail. First, in this embodiment, the shock absorber main body D is connected to the vehicle body side tube 10 in which the piston rod 4 is connected to a vehicle body (not shown) of a straddle vehicle such as a two-wheeled vehicle, and to the axle (not shown) of the saddle vehicle. It is accommodated in a front fork F constituted by an axle side tube 11 slidably inserted into the side tube 10. More specifically, the shock absorber main body D is configured such that the piston rod 4 is connected to the vehicle body side tube 10 via the housing 6 described later, the cylinder 2 is connected to the axle side tube 11, and the vehicle body side tube 10 and the axle side tube 11. Is housed in the space L which is inside the front fork F closed by the vehicle body side tube 10 and the axle side tube 11. In the present embodiment, the front fork F is an inverted front fork in which the axle side tube 11 is inserted into the vehicle body side tube 10, but on the contrary, the vehicle body side tube 10 is connected to the axle side tube 11. It may be an upright front fork to be inserted.

  A suspension spring 12 is interposed between the piston rod 4 and the cylinder 2 of the shock absorber body D. The suspension spring 12 is connected to the vehicle body side tube 10 and the axle side tube via the shock absorber body D. 11, the elastic body is exerted in the direction in which the shock absorber 1 is extended, and the suspension spring 12 elastically supports the vehicle body of the saddle riding vehicle (not shown).

  As shown in FIG. 1, the shock absorber main body D includes a cylinder 2 connected to the axle tube 11, and an extension side chamber R <b> 1 that is slidably inserted into the cylinder 2 and serves as two working chambers. And a piston 3 partitioned into a pressure side chamber R2, a piston rod 4 having one end connected to the piston 3 and the other end connected to the vehicle body side tube 10, and an extension side chamber R1 and a pressure side chamber R2 provided in the piston 3. A damping passage 13 that provides resistance to the flow of liquid that passes through and a pressure-side damping passage 15 that is provided at the lower end of the cylinder 2 and that provides resistance to the flow of liquid from the pressure-side chamber R2 toward the reservoir R. And a bottom member 14 having a suction passage 16 that allows only the flow of liquid toward the chamber R2, and the extending side chamber R1 and the pressure side chamber R2 have hydraulic fluid as liquid. Liquid is filled, it is in the reservoir R liquids and gases are filled.

  In more detail, the cylinder 2 is being fixed to the bottom part of the axle side tube 11 formed in the bottomed cylinder shape via the bottom member 14 fitted by the lower end. A rod guide 17 is provided at the upper end of the cylinder 2 to support the piston rod 4 so as to be slidable.

  The piston rod 4 includes a piston rod body 4a having a hole 4b penetrating in the vertical direction in FIG. 1 along the axial direction, and a piston connecting portion that is fixed to the lower end of the piston rod body 4a in FIG. 4c, and the tip that is the upper end in FIG. 1 is fixed to the upper end of the vehicle body side tube 10 via the housing 6 that houses the spool valve 7 in the damping force adjusting mechanism V. The piston connecting portion 4c includes a communication passage 4d that communicates the hole 4b and the extension side chamber R1, and a check valve that is provided in the middle of the communication passage 4d and that allows only a liquid flow from the extension side chamber R1 toward the hole 4b. 4e, and the annular piston 3 is fixed to the lower end in FIG.

  And the suspension spring 12 is interposed between the rod guide 17 and the cylindrical spring receiver 18 provided on the outer periphery of the housing 6, and the shock absorber body D is urged in the extension direction by the suspension spring 12. The shock absorber 1 is also urged in the extending direction by the suspension spring 12.

  The piston 3 is fixed to the lower end in FIG. 1 of the piston rod 4, and the damping passage 13 provided in the piston 3 is provided in the middle of the passage 13a and the passage 13a that connects the extension side chamber R1 and the pressure side chamber R2. A damping valve 13b is provided to provide resistance to the flow of liquid passing therethrough. In this case, the damping valve 13b is a throttle valve or the like, and the damping passage 13 has a bidirectional flow of the liquid flowing from the expansion side chamber R1 to the compression side chamber R2 and the flow of the liquid from the compression side chamber R2 to the expansion side chamber R1. Although the flow is allowed, two or more passages are provided, and a damping valve that allows only the flow of the liquid from the extension side chamber R1 to the pressure side chamber R2 is provided in a part of the passages, and the other side has a pressure side. A damping valve that allows only the flow of liquid from the chamber R2 toward the extension side chamber R1 may be provided.

  The reservoir R is formed in the space L and outside the buffer body D, and the reservoir R is filled with liquid and gas. The pressure-side damping passage 15 formed in the bottom member 14 resists the flow of the liquid passing through the passage 15a that connects the pressure-side chamber R2 and the reservoir R, and allowing only the flow of the liquid from the pressure-side chamber R2 to the reservoir R. And a one-way passage allowing only the flow of liquid from the pressure side chamber R2 to the reservoir R. On the other hand, the suction passage 16 formed in the bottom member 14 includes a passage 16a that connects the reservoir R and the pressure side chamber R2, and a check valve 16b that allows only the flow of liquid from the reservoir R to the pressure side chamber R2. This is a one-way passage that allows only the flow of liquid from the reservoir R to the pressure-side chamber R2 in the opposite direction to the pressure-side attenuation passage 15. In the shock absorber 1, since the compression side damping force can be generated by the damping valve 15b, a passage allowing only the flow of the liquid from the compression side chamber R2 to the extension side chamber R1 is provided as described above. In this case, it is not necessary to provide a damping valve in the passage.

  Next, the damping force adjusting mechanism V will be described. The damping force adjusting mechanism V is provided in the middle of the flow path 5 described above, and includes a housing 6 having a hollow portion 6a, a spool valve 7 that is slidably inserted into the hollow portion 6a of the housing 6, The spool valve 7 is used as a movable iron core and includes a solenoid 8 that drives the spool valve 7 within the hollow portion 6a.

  As shown in FIGS. 1 and 2, the housing 6 is formed of a synthetic resin material and has a cylindrical shape. The housing 6 has a hollow portion 6a that opens from the lower end in FIG. An annular groove 6b provided on the inner circumference along the circumferential direction, a port 6c that opens from the side and communicates with the hollow portion 6a through the annular groove 6b, and opens from the upper end in FIG. 2 to the hollow portion 6a. An accommodating portion 6d having a larger diameter than the hollow portion 6a and accommodating the solenoid 8, a flange 6e provided on the outer periphery of the upper end, a small diameter portion 6f and a step portion 6g provided with a small diameter on the outer periphery of the lower end, and an outer periphery of the small diameter portion 6f In this case, the outer peripheral side end of the port 6c extends in the radial direction and communicates with the groove 6h described above.

  Further, a screw hole portion 6i is provided in the lower inner periphery of the hollow portion 6a of the housing 6 in FIG. 2, and a screw portion 4f is provided on the outer periphery of the upper end of the piston rod 4, and the screw hole portion 6i A screw can be fastened while inserting the upper end of the piston rod 4. In this embodiment, a nut 19 is screwed onto the screw portion 4f, and the upper end of the nut 19 in FIG. 2 is brought into contact with the lower end of the housing 6 in FIG. Therefore, consideration is given so that the screw hole 6i and the screw 4f are not loosened.

  When the housing 6 is coupled to the piston rod 4 in this way, the hollow portion 6a is coaxially connected in series with the hole 4b of the piston rod 4, and the hollow portion 6a is connected via the hole 4b and the communication path 4d. And communicated with the extension side chamber R1 of the shock absorber body D. The hollow portion 6a is communicated with a reservoir R formed outside the shock absorber body D through a port 6c and a groove 6h. Therefore, in the case of this embodiment, the flow path 5 is constituted by the communication path 4d, the hole 4b, the hollow portion 6a, the annular groove 6b, the port 6c and the groove 6i described above, and the extension side chamber R1 and the reservoir R And communicate with. Further, in this case, the flow path 5 allows only the passage of liquid from the extension side chamber R1 to the reservoir R by the check valve 4e. The check valve for setting the flow path 5 to be one-way is not provided in the piston connecting portion 4c but may be provided in another location. Specifically, for example, the check valve is provided in the hole 4b of the piston rod body 4a. Alternatively, the piston rod body 4a may be provided at the open end of the hole 4b at the upper end in FIG.

  A collar 20 that supports the upper end of a cylindrical spring support 18 that supports the upper end of the suspension spring 12 is fitted to the outer periphery of the small-diameter portion 6f of the housing 6. In this embodiment, the collar 20 is connected to the port 6c. Since the groove 6h is provided to ensure communication between the port 6c and the reservoir R, if the port 6c does not interfere with the collar 20 or the spring support 18, the groove 6h is provided. It can be omitted.

  Further, a screw portion 6 j is provided on the upper outer periphery of the housing 6 in FIG. 2 so that the housing 6 can be screwed to the opening end of the vehicle body side tube 10. The piston rod 4 can be connected to the vehicle body side tube 10.

  The spool valve 7 has a cylindrical shape and is slidably inserted into the hollow portion 6a with one end facing downward, and is fitted to the spool valve main body 21 and the other end of the spool valve main body 21. And a cylindrical magnetic member 22 integrated. The spool valve body 21 is made of a synthetic resin material having a specific gravity smaller than that of the magnetic member 22, and the housing 6 is also made of the same material. As the synthetic resin material, it is preferable to use a material that is slidable and resistant to wear. For example, polyacetal, polybutylene terephthalate, polyphenylene sulfide, polyimide, polyamideimide, polyether ketone can be used, and When the liquid is oil, a phenol resin can be used in addition to the above.

  The spool valve main body 21 receives the pressure in the flow path 5 at the lower end in FIG. 2 as one end, and an outer space 21a that opens from one end and an outer periphery provided along the circumferential direction. An annular groove 21b, a notch 21c formed in the outer periphery along the axial direction and connected to the outer annular groove 21b, a through hole 21d that opens from the outer annular groove 21b and communicates with the empty portion 21a, and an empty portion A pressure introducing hole 21e that guides the pressure of the flow path 5 to the upper end side in FIG. 2 that communicates with 21a and serves as the other end of the spool valve 7, and a small diameter portion that is provided at the upper end in FIG. 21f. That is, in this spool valve body 21, the notch 21c, the outer peripheral annular groove 21b, and the through hole 21d form a spool port S that communicates the inside and outside of the spool valve body 21. In the above description, the notch 21c does not penetrate the meat of the spool valve main body 21, but the spool port is configured only by this notch so as to penetrate the spool valve main body 21 and communicate the inside and outside of the spool valve main body 21. You may make it do.

  The magnetic member 22 is formed of a magnetic material such as iron, nickel, cobalt, an alloy containing these, or ferrite, and has a cylindrical shape. The base 22a on the upper side in FIG. 2 and the bottom from the base 22a in FIG. It extends to the spool valve main body 21 side, and is provided with a socket 22b that is thinner than the base 22a and has a single outer diameter.

  When the spool valve main body 21 and the magnetic member 22 are integrated, although not shown, the spool valve main body 21 injects a synthetic resin material into a mold for molding the spool valve main body 21. The magnetic member 22 is accommodated in advance in the mold, and the synthetic resin material heated is injected into the mold, so that the spool valve body 21 is molded and at the same time the small diameter portion 21f of the spool valve body 21 is inserted into the socket 22b of the magnetic material 22. Are integrated. That is, the magnetic material 22 is integrated into the spool valve body 21 by insert molding.

  An annular recess 22c is formed on the inner periphery of the socket 22b. When the magnetic member 22 is housed in the mold and insert-molded when the spool valve body 21 is molded as described above, the synthetic resin material is placed in the recess 22c. When the synthetic resin material enters and hardens, an annular convex portion 21g is formed on the outer periphery of the small diameter portion 21f of the spool valve main body 21, and the concave portion 22c and the convex portion 21g engage with each other, so that the spool valve main body 21 and the magnetic member are engaged. The separation of 22 is strongly prevented.

  The spool valve main body 21 and the magnetic member 22 can be integrated without using insert molding, and the socket 22b may be fitted with an adhesive applied to the small diameter portion 21f.

  The solenoid 8 includes an inner cylinder 30a, an outer cylinder 30b, an inner cylinder 30a and an annular bottom portion 30c connecting the lower ends of the outer cylinder 30b in FIG. 2 and a case 30 formed of a magnetic material, and a coil 31a as a mold resin 31b. A cylindrical mold coil 31 which is formed by molding and accommodated between the outer cylinder 30b and the inner cylinder 30a, and a cylindrical and magnetic base which is inserted into the inner periphery of the mold coil 31 33, a nonmagnetic ring 32 that provides an annular gap between the base 33 and the inner cylinder 30 a of the case 30, an adjuster 34 that is screwed into the base 33, and an adjuster 34 and a spool valve 7. And an urging spring 35 to be mounted. The solenoid 8 can drive the spool valve 7 by energizing the coil 31a with the magnetic member 22 in the spool valve 7 as a movable iron core.

  The inner cylinder 30a of the case 30 has an inner diameter set so that the spool valve 7 can be inserted movably. Even if the inner cylinder 30a is accommodated in the accommodating portion 6d of the housing 6 together with the outer cylinder 30b, the movement of the spool valve 7 Is not disturbed. The inner diameter of the inner cylinder 30a may be set so that the spool valve 7 can slide. In this case, the inner circumference of the inner cylinder 30a is flush with the hollow portion 6a of the housing 6. do it.

  Further, the positioning of the case 30 in the radial direction with respect to the housing 6 may be performed by fitting the outer cylinder 30b and the housing portion 6c of the housing 6 or the inside of the hollow portion 6a of the housing 6 and the inner cylinder 30a of the case 30. When the spool valve 7 is brought into sliding contact with the circumference, the spool valve 7 can be used. The case 30 and the housing 6 are tightly sealed by an annular seal 36 interposed between the annular bottom 30c of the case 30 and the housing 6.

  The molded coil 31 includes a cylindrical connector 31d that houses a power supply terminal 31c for energizing the coil 31a. The connector 31d is integrated with the coil 31a by a molded resin 31b. By connecting the power supply terminal 31c in the connector 31d to an external power supply (not shown), the coil 31a can be energized from the outside.

  The base 33 has a cylindrical shape and is inserted into the inner periphery of the molded coil 31, and includes an annular convex portion 33a that protrudes toward the spool valve side on the outer periphery of the spool valve side end, which is the lower end in FIG. The outer periphery of the annular convex portion 33a is chamfered in a tapered shape. A nonmagnetic ring 32 formed of a material such as nonmagnetic stainless steel such as aluminum, copper, zinc, SUS305 or high manganese steel is interposed between the annular protrusion 33a and the inner cylinder 30a of the case 30. The nonmagnetic ring 32 is integrated with the case 30 and the base 33 by brazing or the like. The nonmagnetic ring 32 forms a gap between the base 33 and the case 30 so that the magnetic member 22 can be attracted by the base 33 that is magnetized when the coil 31a is energized, and the case 30 and the base 33 are integrated. Also, it plays a role of sealing between the case 30 and the base 33.

  Further, an annular end ring 38 having a split 38a that allows the connector 31d to pass therethrough is laminated on the outer periphery of the base 33 and on the upper ends of the mold coil 31 and the case 30 in FIG. A nut member 37 is screwed to the inner periphery of the upper end in FIG. 2 which is the opening end of the housing portion 6 c of the end ring 38 from above in FIG. 2, and the mold coil 31 and the housing 6 are joined by the nut member 37 and the housing 6. The member is fixed to the housing 6 by sandwiching the case 30, the nonmagnetic ring 32 integrated with the case 30, and the base 33.

  In order to provide a gap between the base 33 and the inner cylinder 30 a of the case 30, a non-magnetic ring 32 is interposed, and a cylindrical filler ring is provided on the outer periphery of the inner cylinder 30 a of the case 30 and the outer periphery of the base 33. The case 30 and the base 33 may be integrated while providing a gap so that the non-magnetic ring 32 can be omitted. When using the filler ring, it is necessary to secure a fitting length with the filler ring, so that the axial length of the inner cylinder 30a of the case 30 is integrated with the case 30 and the base 33 by the nonmagnetic ring 32. Longer than. In other words, it is advantageous in that the total length of the non-movable part of the solenoid 8 can be shortened by adopting a structure in which the case 30 and the base 33 are integrated by the nonmagnetic ring 32.

  In turn, the adjuster 34 is axial and has a screw portion on the outer periphery of the base end, which is the upper end in FIG. 2, and is screwed onto the inner periphery of the cylindrical portion 33a of the base 33. A biasing spring 35 is interposed between the lower end and the spool valve 7 in a compressed state.

  Here, the pressure introducing hole 21e in the spool valve 7 opens from the upper end in FIG. 2 which is the other end of the spool valve 7 and communicates with the empty portion 21a, and the portion connected to the empty portion 21a is set to have a small diameter. A step portion 21h is formed in the pressure introducing hole 21e, and a biasing spring 35 is interposed between the step portion 21h and the adjuster 34. Then, the adjuster 34 is moved forward and backward in the vertical direction in FIG. 2 which is the axial direction with respect to the base 33 in the manner of a feed screw, and the compression length of the biasing spring 35 is adjusted to bias the spool valve 7. The initial load applied by the spring 35 can be adjusted.

  When the solenoid 8 configured in this way is energized to the coil 31a, the base 33 is magnetized to generate an attractive force for attracting the magnetic member 22, and the spool valve 7 is resisted against the urging force of the urging spring 35. 2 can be driven upward. The magnetic member 22 is thicker than the socket 22b in a state where the magnetic member 22 is attracted to the base 33, that is, in a state where the upper end in FIG. 2 of the base portion 22a of the magnetic member 22 is completely in contact with the inner periphery of the lower end in FIG. The base portion 22a of the case 30 is opposed to the inner cylinder 30a of the case 30 in the radial direction, and the socket 22b is fitted to the outer periphery of the other end of the spool valve main body 21 and faces the inner cylinder 30a. Therefore, consideration is given so that the magnetic flux density is not saturated due to the cross-sectional area of the magnetic path becoming too small and the attractive force is not reduced.

  While the vehicle is traveling, a large acceleration in the vertical direction acts on the shock absorber 1. Since the direction of this acceleration substantially coincides with the sliding direction of the spool valve 7, in this embodiment, the spool valve 7 In order to reduce the weight of the spool valve 7 due to the acceleration and to suppress the vibration of the spool valve 7, the magnetic member 22 functioning as the movable iron core and the composite member having a specific gravity smaller than that of the magnetic member 22. The spool valve body 21 is formed of a resin material, and the weight of the spool valve 7 as a movable portion in the damping force adjusting mechanism V is reduced. Further, in this embodiment, in order to further reduce the weight of the spool valve main body 21, the inner diameters of the hollow portion 21a and the pressure introducing hole 21e are increased to reduce the thickness as much as possible.

  In addition, since the structure which accommodates the urging | biasing spring 35 in the magnetic member 22 is employ | adopted, the accommodation space of the urging | biasing spring 35 is ensured and the full length of the solenoid 8 including the adjuster 34 can be shortened.

  Returning to the above, when the spool valve 7 is urged by the urging spring 35 as described above, the spool valve 7 is positioned at the lowest position in the hollow portion 6a. Specifically, when the lower end of the spool valve 7 comes into contact with the upper end of the piston rod 4, further movement of the spool valve 7 toward the piston rod 4 is restricted, and the spool valve 7 is positioned at the lowest position. .

  At the lowest position, the notch 21c of the spool valve 7 faces the annular groove 6b, the spool port S and the port 6c are in communication with each other, and the flow path 5 is opened.

  Further, in this embodiment, the coil 31a is energized to suck the spool valve 7 toward the base 33, and the spool valve 7 is retracted upward in FIG. 2 in the hollow portion 6a, whereby the annular groove 6b. The wrap area of the notch 21c (opposite area between the annular groove 6b and the notch 21c) can be reduced to narrow the flow path 5 (reduce the flow path area). Furthermore, the lap area of the annular groove 6b and the notch 21c can be adjusted by controlling the movement amount of the spool valve 7 by the energization amount of the coil 31a. That is, the spool valve 7 can be driven upward in FIG. 2 by energizing the coil 31a, and if the energization to the coil 31a is stopped, the spool valve 7 can be driven downward in FIG. The position of the valve 7 can be adjusted. In this way, the solenoid valve 8 can drive the spool valve 7 in the vertical direction in FIG.

  Then, by narrowing the flow path 5 with the annular groove 6b and the notch 21c, the resistance given to the flow of the liquid that is going to pass through the flow path 5 is increased as compared with the case where the spool valve 7 is in the lowest position. be able to. In this case, the larger the retraction amount of the spool valve 7, the smaller the lap area between the annular groove 6b and the notch 21c and the greater the degree of restriction of the flow path 5, so that the retraction amount of the spool valve 7 increases. Thus, the resistance given to the flow of liquid passing through the flow path 5 is increased.

  The annular groove 6b is provided to enable communication between the port 6c and the notch 21c in the spool port S even when the spool valve 7 rotates in the circumferential direction. Note that an annular groove may be provided on the outer periphery of the spool valve main body 21 and a notch may be provided in the housing 6. In addition, the spool port S may be constituted by only the through hole 21d and communicate with the port 6c of the housing 6 regardless of the notch 21c. In this case, the annular groove 6b can be omitted. Further, the notch 21c and the annular groove 6b of the spool valve body 21 may be eliminated, and the spool port S may be configured by the outer peripheral annular groove 21b and the through hole 21d, and communicated with the port 6c.

  The pressure in the flow path 5 not only acts on the lower end serving as one end of the spool valve 7, but also acts on the upper end serving as the other end of the spool valve 7 by the pressure introduction hole 21e. A thrust force that pushes the spool valve 7 from one end side to the other end side by the pressure of the passage 5 (an upward thrust force in FIG. 2) and a thrust force that pushes the spool valve 7 from the other end side to the one end side by the pressure of the flow path 5 (see FIG. 2 and a downward thrust) are set equal to each other. That is, the pressure receiving area on one end side of the spool valve on which the pressure in the flow path acts so as to push the spool valve 7 upward in FIG. 2, and the spool on which the pressure in the flow path acts so as to push down the spool valve 7 in FIG. The pressure receiving area on the other end side of the valve is set to be equal. It should be noted that the pressure receiving area on one end side of the spool valve that receives the pressure of the flow path 5 of the spool valve 7 and the pressure receiving area on the other end side of the spool valve need not necessarily be on both end faces of the spool valve 7. That is, the area that receives the pressure of the flow path 5 so as to press the spool valve 7 downward in FIG. 2 and the area that receives the pressure of the flow path 5 so as to press the spool valve 7 upward in FIG. What is necessary is just to provide the thrust and the other end, for example, by providing a step portion in the middle of the spool valve 7 and pressing the spool valve 7 that applies the pressure of the flow path 5 to the upper and lower surfaces of the step portion from one end side to the other end side. You may make it make the thrust pressed from the side to one end side equal.

  Then, the action | operation of the buffer 1 comprised in this way is demonstrated. At the time of extension of the shock absorber 1 in which the piston 3 moves upward in FIG. 1 with respect to the cylinder 2, a resistance is given by the damping passage 13 to the flow of the liquid moving from the expansion side chamber R1 to the compression side chamber R2 compressed by the piston 3. The damping force adjusting mechanism V provides resistance to the liquid flow from the extension side chamber R1 to the reservoir R. That is, in this embodiment, the shock absorber 1 exerts the extension side damping force by the damping passage 13 and the damping force adjusting mechanism V during extension. Note that liquid is supplied from the reservoir R through the suction passage 16 provided in the bottom member 14 to the pressure side chamber R2 that expands when extended, and the piston rod 4 retreats from the cylinder 2 when the shock absorber 1 extends. The change in the volume in the cylinder 2 occurring at is compensated.

  On the contrary, when the shock absorber 1 in which the piston 3 moves downward in FIG. 1 with respect to the cylinder 2 is contracted, the damping passage 13 resists the flow of the liquid moving from the compression side chamber R2 to the extension side chamber R1. In addition, the volume-reduced liquid in the cylinder 2 generated by the piston rod 4 entering the cylinder 2 is discharged to the reservoir R through the compression-side damping passage 15 of the bottom member 14 to change the volume in the cylinder 2. Therefore, the pressure side damping passage 15 also provides resistance to the liquid flow. Therefore, when the shock absorber 1 contracts, the damping passage 13 and the compression side damping passage 15 exert a compression side damping force. In this case, the fluid does not flow through the flow path 5, so the damping force adjusting mechanism V Does not participate in the generation of the compression damping force.

  That is, in this embodiment, in the damping force adjusting mechanism V, the spool valve 7 can be driven to make the flow passage area of the flow passage 5 variable. The damping force can be adjusted.

  When adjusting the damping force, the spool valve 7 is driven by the solenoid 8 as necessary to change the flow path area of the flow path 5. The magnetic member 22 and the magnetic member 22 function as a movable iron core. The spool valve body 21 is made of a synthetic resin material having a small specific gravity, and the entire weight of the spool valve 7 which is a movable part in the damping force adjusting mechanism V is compared with the case where the whole is made of a magnetic member. Since the weight is reduced, the inertial force that acts on the spool valve 7 due to the large acceleration in the expansion / contraction direction that is input to the shock absorber 1 while the vehicle is running is minimized, and the vibration of the spool valve 7 is suppressed. Therefore, it is possible to prevent the damping force generated by the shock absorber 1 from changing vibrationally without becoming the aimed damping force, and to exhibit a stable damping force.

  In this way, a stable damping force can be exhibited while using the solenoid 8. In other words, the solenoid 8 can be used for the shock absorber 1. The damping force can be adjusted by active control such as skyhook control while exhibiting a stable damping force, and the shock absorber 1 of the present invention is particularly bad road where a large vertical acceleration acts. It is most suitable for shock absorbers used in saddle riding vehicles suitable for running.

  Furthermore, since the housings 6 with which the spool valve main body 21 is slidably contacted are formed of the same synthetic resin material, the linear expansion coefficients are equal. Therefore, even if the temperature of the spool valve body 21 and the housing 6 changes due to a change in the temperature of the liquid in the shock absorber 1 or a change in the outside air temperature, the spool valve body 21 is strongly tightened on the inner periphery of the hollow portion 6a of the housing 6. It is never done. Thereby, the smooth movement of the spool valve 7 with respect to the housing 6 is ensured.

  Further, the magnetic member 22 is formed in a cylindrical shape and integrated with the other end of the spool valve main body 21, opens from the other end side of the spool valve main body 21, communicates with the empty portion 21 a, and on the other end side of the spool valve 7. The pressure introduction hole 21e for guiding the pressure of the flow path 5 is provided. The pressure of the flow path 5 acts on both end sides by the pressure introduction hole 7c of the spool valve 7, and the pressure receiving areas of both are made equal. That is, the thrust received from one end side due to the pressure of the flow path 5 acting on the spool valve 7 is made equal to the thrust received from the other end side. As a result, the thrust that presses the spool valve 7 from one end side to the other end side by the pressure of the flow path 5 and the thrust that presses the spool valve 7 from the other end side to the one end side compete with each other, and the spool valve 7 is moved in any axial direction. In the shock absorber 1, even if the pressure of the flow path 5 becomes high, the shock absorber 1 does not affect the adjustment of the flow path area of the flow path 5 by the solenoid 8. As a result, the problem that the thrust of the solenoid 8 must be increased so as to overcome the pressure in the flow path 5 can be solved, and the damping force can be adjusted by driving the spool valve 7 with the small solenoid 8.

  Thus, since the spool valve 7 does not move due to the pressure of the flow path 5, in this shock absorber 1, the generated damping force of the shock absorber 1 does not fluctuate due to the pressure of the flow path 5, A sufficient vibration damping effect can be obtained.

  Further, since the spool valve 7 can be driven without increasing the size of the solenoid 8, the shock absorber 1 can be mounted on a small vehicle such as a saddle vehicle without impairing the mountability. There is no problem of high economic efficiency.

  Furthermore, since the spool valve 7 is a movable iron core, the solenoid valve 8 and the spool valve 7 are arranged close to each other so that the spool valve 7 can be driven without using a separate long movable iron core. In addition, since the weight of the movable part such as the spool valve 7 can be reduced, the damping force can be prevented from changing due to the vibration acceleration input to the shock absorber 1, and stable generation and adjustment of the damping force can be achieved. It becomes possible.

  The solenoid 8 includes an inner cylinder 30a through which the spool valve 7 can be inserted, an outer cylinder 30b disposed on the outer peripheral side of the inner cylinder 30a, and an annular bottom 30c that connects the inner cylinder 30a and the outer cylinder 30b. , A coil 31a accommodated in the case 30, and an inner cylinder 30a of the case 30 opposed to each other through an annular gap and inserted into the inner periphery of the coil 31a and energizing the coil 31a. A base 33 for sucking the spool valve 7, and the magnetic member 22 is adsorbed to the base 33, and at least a base portion 22 a radially facing the inner cylinder 30 a of the case 30, and the base portion 22 a toward the spool valve body 21 side. A cylindrical socket 22b that is extended and faces the inner cylinder 30a of the case 30 in the radial direction and is integrated with the spool valve body 21 is provided. As a result, the thickness of the base portion 22a facing the inner cylinder 30a of the case 30 can always be secured, so that the cross-sectional area of the magnetic path becomes too small, the magnetic flux density is saturated, and the attractive force is reduced. Therefore, the vibration of the spool valve 7 can be further suppressed, and it is possible to contribute to more stable damping force.

  Further, the shock absorber 1 includes a vehicle body side tube 10 connected to the vehicle body of the saddle riding vehicle and an axle side tube 11 connected to the axle of the saddle riding vehicle, and includes a housing 6 connected to the tip of the piston rod 4. The piston rod 4 is connected to the vehicle body side tube 10 and the cylinder 2 is connected to the axle side tube 11 to accommodate the shock absorber body D in the space L formed by the vehicle body side tube 10 and the axle side tube 11. The reservoir R is formed in the space L and outside the shock absorber body D, and the flow path 5 passes through the piston rod 4 to connect the compression side chamber R2 or the extension side chamber R1 in the cylinder 2 and the hollow portion 6a of the housing 6. The port 6 b communicates with the reservoir R. As a result, the damping force adjusting mechanism V can be concentrated above the vehicle body side tube 10, energization of the solenoid 8 is facilitated, and the saddle riding in which the damping force adjusting mechanism V is damped by the shock absorber 1. Since both the vehicle body sides are connected, vibration of the spool valve 7 during traveling of the vehicle can be suppressed, and fluctuations in damping force due to the vibration can be suppressed.

  The shock absorber 1 includes a hole 4b in which the piston rod 4 forms part of the flow path 5 along the axial direction, and the piston rod 4 and the housing 6 connected to the tip of the piston rod 4 are hollow. The portion 6a and the hole 4b are connected so as to be coaxial and in series. As a result, the driving direction of the spool valve 7 coincides with the axial direction of the piston rod 4, so that the solenoid 8 that drives the spool valve 7 does not protrude sideways, and the driving direction of the spool valve 7 is changed to the axis of the piston rod 4. The shock absorber 1 can be made slimmer as compared with the case where the crossing direction is set to the direction. Of course, in exchange for this effect, the driving direction of the spool valve 7 can be made different from the expansion / contraction direction of the shock absorber 1, that is, it can be made not to coincide with the axis of the piston rod 4. Therefore, the vibration in the drive direction of the spool valve 7 can be suppressed by the vibration.

  Further, the shock absorber 1 includes a housing portion 6d in which the housing 6 is connected to the hollow portion 6a and accommodates the solenoid 8, and the housing portion 6d is fixed to the opening end of the vehicle body side tube 10 with the housing portion 6d facing outward in FIG. An adjuster 34 for adjusting the initial load of the biasing spring 35 of the solenoid 8 is provided to face the shock absorber 1 from the opening end of the vehicle body side tube 10. Thereby, since the adjuster 34 can be externally operated, the initial load can be easily adjusted. In addition, when the spring constant of the urging spring 35 varies, by performing this initial load adjustment, it is possible to perform a uniform damping force adjustment without variation among products. The damping force adjustment of the shock absorber 1 may be made uniform by correcting the amount of current applied to the solenoid 8.

  In addition, the shock absorber 1 includes a notch 21c, which is a narrow groove provided along the axial direction on the outer periphery of the spool valve body 21, and the housing 6 extends along the inner periphery of the hollow portion 6a in the circumferential direction. An annular groove 6b communicated with the port 6c is provided. The spool valve 7 is driven by the solenoid 8, and the flow path 5 is restricted by the notch 21c and the annular groove 6b to adjust the damping force. Accordingly, the circumferential displacement between the port 6c and the spool port S is allowed by the annular groove 6b, and the flow channel area in the flow channel 5 can be changed in a small and proportional manner by the notch 21c.

  As described above, the damping force adjusting mechanism V is configured such that the flow path 5 allows the liquid to pass only when the shock absorber 1 extends, and generates the expansion side damping force of the shock absorber 1. Since it functions as a damping force generating element, the extension side damping force of the shock absorber 1 can be adjusted, but the flow path 5 is set so as to allow passage of liquid only when the shock absorber 1 contracts. Thus, the compression side damping force may be adjusted by functioning as a damping force generation element that generates the compression side damping force of the shock absorber 1. That is, if the pressure side chamber R2 is communicated with the hollow portion 4b instead of the expansion side chamber R1 in the communication passage 4d provided in the piston connecting portion 4c, the damping force adjusting mechanism V can adjust the compression side damping force. it can. If it does in this way, it can set so that a liquid may pass through channel 5 only at the time of contraction operation of shock absorber 1.

  Further, when the flow path 5 is set so as to communicate the expansion side chamber R1 and the compression side chamber R2, the damping force adjustment mechanism V performs the damping force adjustment both when the shock absorber 1 is extended and contracted. It may be set as follows. In this case, for example, the housing is used as a piston rod or piston coupling part to accommodate the spool valve, and the piston rod or piston coupling part is provided with a flow path that connects the expansion side chamber R1 and the pressure side chamber R2, and the spool valve is driven by a solenoid. Just do it.

  Further, in the above description, the flow path area of the flow path 5 is set to decrease when the spool valve 7 is retracted. However, the spool valve 7 is set at the lowest position so that the flow path area of the flow path 5 is minimized. The flow path area of the flow path 5 may be increased by retreating the spool valve 7 or the flow path 5 may be completely blocked. .

  Further, in the above embodiment, the connector 31d for energizing the coil 31a is integrated with the molded coil 31, but the connector 31d is separated from the molded coil 31, and the coil 31a and the power supply terminal 31c are connected by a cord. Alternatively, the connector and the power terminal may be eliminated, and the coil 31a may be connected to an external power source only through a cord.

  In addition, the shock absorber body D may be configured to exhibit a damping force only when extended when the damping force adjusting mechanism V exhibits the damping force when the shock absorber 1 is extended, or the damping force adjusting mechanism. When V exhibits a damping force when the shock absorber 1 contracts, a configuration in which the damping force is exhibited only when the shock absorber 1 contracts may be adopted. The shock absorber 1 is applied to the vehicle in a pair of left and right to support the wheels. In such a case, it may be set such that one of the left and right shock absorbers 1 exhibits a damping force when extended, and the other exhibits a damping force when contracted.

  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.

DESCRIPTION OF SYMBOLS 1 Buffer 2 Cylinder 3 Piston 4 Piston rod 4b Hole 5 Flow path 6 Housing 6a Hollow part 6b Annular groove 6c Port 6d Housing part 7 Spool valve 8 Solenoid 10 Car body side tube 11 Axle side tube 21 Spool valve main body 21a Empty part 21c Notch 21e Pressure introducing hole 22 Magnetic member 22a Base 22b Socket 30 Case 30a Inner cylinder 30b Outer cylinder 30c Annular bottom 31a Coil 33 Base 34 Adjuster 35 Biasing spring D Buffer body L Space R Reservoir R1 Pressure side chamber R2 Extension side chamber S Spool port V Damping force adjustment mechanism

Claims (9)

A cylinder, a piston that is slidably inserted into the cylinder and divides the cylinder into a pressure side chamber and an extension side chamber, and a piston rod that is inserted into the cylinder and connected to the piston A shock absorber body, a flow path that allows liquid to pass through one or both of the expansion and contraction of the shock absorber body, and a damping force adjustment mechanism that is provided in the middle of the flow path to adjust the damping force In the shock absorber
The damping force adjusting mechanism includes a spool valve provided in the flow path, and a solenoid that drives the spool valve in the flow path using the spool valve as a movable iron core,
A shock absorber characterized in that the spool valve includes a spool valve main body formed of a synthetic resin material, and a magnetic member that is integrated with the spool valve main body and functions as a movable iron core of the solenoid. The damping force adjusting mechanism includes a hollow part that forms a part of the flow path and a port that opens from the outside and communicates with the hollow part and forms a part of the flow path together with the hollow part. And a housing formed of the same resin material as the spool valve body,
The spool body includes an empty portion that opens from one end side, and a spool port that opens from the outer periphery and communicates with the empty portion,
The spool valve is slidably inserted into the hollow portion,
The shock absorber according to claim 1, wherein the liquid is allowed to pass through the spool port and the port. The shock absorber according to claim 1 or 2, wherein the magnetic member is integrated into the spool valve body by insert molding. The solenoid includes an inner cylinder that allows the spool valve to be inserted; an outer cylinder that is disposed on an outer peripheral side of the inner cylinder; and a case that includes an annular bottom portion that connects the inner cylinder and the outer cylinder; A coil housed in the case, and a base that is inserted into the inner periphery of the coil and sucks the spool valve by energizing the coil,
The magnetic member is adsorbed to the base and has at least a base portion that radially opposes the inner cylinder of the case, and extends from the base portion to the spool valve body side and opposes the inner cylinder of the case in the radial direction. A shock absorber according to any one of claims 1 to 3, further comprising a cylindrical socket into which the spool valve body is integrated. The magnetic member has a cylindrical shape and is integrated with the other end of the spool valve main body. The pressure of the flow path is applied to one end side of the spool valve, and the other end of the spool valve is applied to the spool valve main body. A pressure introduction hole that opens from the side and communicates with the empty portion to guide the pressure of the flow path on the other end side of the spool valve, and the thrust received from one end side due to the flow path pressure acting on the spool valve and the other end side The shock absorber according to any one of claims 1 to 4, wherein thrusts received from the same are made equal. A vehicle body side tube connected to the vehicle body of the saddle riding vehicle, and an axle side tube connected to the axle of the saddle riding vehicle;
The piston rod is connected to the vehicle body side tube through the housing connected to the tip of the piston rod, and the cylinder is connected to the axle side tube to connect the shock absorber body to the vehicle body side tube and the axle side tube. And housed in the space formed by
Forming a reservoir in the space and outside the shock absorber body,
The flow path penetrates the piston rod in the axial direction, the pressure side chamber or the extension side chamber in the cylinder communicates with the hollow portion of the housing, and the port communicates with the reservoir. The shock absorber according to any one of claims 2 to 4. The piston rod has a hole that forms a part of the flow path along the axial direction, and the piston rod and the housing connected to the tip of the piston rod coaxially connect the hole and the hollow part. The shock absorber according to claim 6, wherein the shock absorbers are connected in series. The housing includes a housing portion that is connected to the hollow portion and houses the solenoid, and is fixed to the opening end of the vehicle body side tube with the housing portion facing outside, and the solenoid biases the spool valve. The shock absorber according to claim 6 or 7, further comprising an urging spring and an adjuster for adjusting an initial load of the urging spring, wherein the adjuster is exposed to the outside from an opening end of the vehicle body side tube. The spool port has a notch formed by a narrow groove provided along the axial direction on the outer periphery of the spool valve body, and the housing has an annular groove communicated with the port along the circumferential direction on the inner periphery of the hollow portion. The shock absorber according to any one of claims 2 to 8, further comprising: a solenoid valve that drives a spool valve to adjust the damping force by restricting the flow path with the notch and the annular groove.

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