WO2017047360A1 - Damper - Google Patents

Damper Download PDF

Info

Publication number
WO2017047360A1
WO2017047360A1 PCT/JP2016/075062 JP2016075062W WO2017047360A1 WO 2017047360 A1 WO2017047360 A1 WO 2017047360A1 JP 2016075062 W JP2016075062 W JP 2016075062W WO 2017047360 A1 WO2017047360 A1 WO 2017047360A1
Authority
WO
WIPO (PCT)
Prior art keywords
piston
flow path
core
thermal expansion
shock absorber
Prior art date
Application number
PCT/JP2016/075062
Other languages
French (fr)
Japanese (ja)
Inventor
康裕 米原
睦 小川
Original Assignee
Ｋｙｂ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ｋｙｂ株式会社 filed Critical Ｋｙｂ株式会社
Publication of WO2017047360A1 publication Critical patent/WO2017047360A1/en

Links

Images

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/50—Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics
    • F16F9/52—Special means providing automatic damping adjustment, i.e. self-adjustment of damping by particular sliding movements of a valve element, other than flexions or displacement of valve discs; Special means providing self-adjustment of spring characteristics in case of change of temperature
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16F—SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
    • F16F9/00—Springs, vibration-dampers, shock-absorbers, or similarly-constructed movement-dampers using a fluid or the equivalent as damping medium
    • F16F9/32—Details
    • F16F9/53—Means for adjusting damping characteristics by varying fluid viscosity, e.g. electromagnetically

Definitions

  • the present invention relates to a shock absorber.
  • JP2009-228861A includes a piston core, a piston ring, and a piston core that includes a piston core having a coil wound around the outer periphery and a piston ring disposed on the outer periphery of the piston core.
  • a shock absorber in which a magnetorheological fluid passes through a flow path formed between the two is disclosed.
  • the working fluid of the shock absorber including the magnetorheological fluid generally changes in viscosity due to a change in temperature. For this reason, in the shock absorber described in JP2009-228861A, a temperature compensation valve is provided in the bypass flow path in order to obtain a stable damping force even when the temperature of the magnetorheological fluid changes.
  • the bypass channel is configured by connecting a plurality of orthogonal holes. For this reason, the man-hour which processes a bypass flow path increases, and there exists a possibility that manufacturing cost may rise as a result.
  • An object of the present invention is to generate a required damping force regardless of a temperature change of a working fluid with a simple configuration.
  • the shock absorber includes a cylinder in which a working fluid is sealed, a piston that is slidably disposed in the cylinder, and that defines a pair of fluid chambers in the cylinder, and the piston A piston rod connected to the cylinder and extending to the outside of the cylinder.
  • the piston communicates with the pair of fluid chambers, and the working fluid circulates by the movement of the piston and resists the circulated working fluid.
  • a main flow path that provides the flow path
  • a bypass flow path that is provided in parallel with the main flow path and communicates with a pair of the fluid chambers, and is inserted into the bypass flow path, and the bypass flow path according to the temperature of the working fluid
  • a temperature compensation unit that changes the flow passage area of the bypass flow passage by being deformed in a direction orthogonal to the first flow passage.
  • FIG. 1 is a front sectional view of a magnetorheological fluid shock absorber according to an embodiment of the present invention.
  • FIG. 2 is a sectional view taken along line II-II in FIG.
  • FIG. 3 is an enlarged view of a portion III in FIG.
  • FIG. 4 is an enlarged view of a magnetorheological fluid shock absorber according to a modification of the embodiment of the present invention.
  • the shock absorber is a shock absorber 100 whose damping coefficient can be changed by using a magnetorheological fluid whose apparent viscosity is changed by the action of a magnetic field as a working fluid.
  • the shock absorber 100 is interposed, for example, between a vehicle body and an axle in a vehicle such as an automobile.
  • the shock absorber 100 generates a damping force that suppresses vibration of the vehicle body by an expansion and contraction operation.
  • the shock absorber 100 includes a cylinder 10 in which a magnetorheological fluid is sealed, a piston 20 that is slidably disposed in the cylinder 10, and a piston rod 21 that is connected to the piston 20 and extends to the outside of the cylinder 10. And comprising.
  • the piston rod 21 moves forward and backward with respect to the cylinder 10 as the piston 20 slides.
  • the cylinder 10 is formed in a bottomed cylindrical shape.
  • the magnetorheological fluid sealed in the cylinder 10 has an apparent viscosity that is changed by the action of a magnetic field, and is a liquid in which fine particles having ferromagnetism are dispersed in a liquid such as oil.
  • the viscosity of the magnetorheological fluid changes according to the strength of the applied magnetic field, and returns to its original state when the magnetic field is no longer affected.
  • a gas chamber (not shown) in which gas is sealed is defined via a free piston (not shown).
  • the volume change in the cylinder 10 due to the advance / retreat of the piston rod 21 is compensated by the gas chamber.
  • the piston 20 defines a fluid chamber 11 and a fluid chamber 12 in the cylinder 10.
  • the fluid chamber 11 and the fluid chamber 12 communicate with each other through a main channel 22 and a bypass channel 23 formed in the piston 20.
  • the configuration of the piston 20 will be described later in detail.
  • the piston rod 21 is formed coaxially with the piston 20, and one end 21 a of the piston rod 21 is fixed to the piston 20.
  • the other end 21 b of the piston extends to the outside of the cylinder 10.
  • the piston rod 21 has a cylindrical shape in which a through hole 21c is formed across one end 21a and the other end 21b.
  • a male screw 21 d that is screwed with the piston 20 is formed on the outer peripheral surface of the piston rod 21.
  • the piston 20 includes a piston core 30 attached to the piston rod 21, an annular flux ring 35 as a ring body surrounding the outer periphery of the piston core 30, and an annular plate 40 provided on the piston core 30 and supporting the flux ring 35. And a fixing nut 50 that is attached to the outer peripheral surface of the piston core 30 and fixes the plate 40 to the piston core 30.
  • the piston core 30 is formed by being divided into a coil assembly 33 provided with a coil 33a and first and second cores 31 and 32 sandwiching the coil assembly 33.
  • the first and second cores 31 and 32 are fastened by a pair of bolts (not shown) with the coil assembly 33 sandwiched therebetween.
  • the first core 31 has a cylindrical first small-diameter portion 31a, a cylindrical second small-diameter portion 31b formed with a larger diameter than the first small-diameter portion 31a, and a second small-diameter portion 31b. And a cylindrical large-diameter portion 31c formed to have a large diameter.
  • the first core 31 is formed of a magnetic material.
  • a female screw 31f that is screwed with the male screw 21d of the piston rod 21 is formed on the inner peripheral surface of the first small diameter portion 31a.
  • the first core 31 is fastened to the piston rod 21 by screwing the female screw 31 f of the first small diameter portion 31 a and the male screw 21 d of the piston rod 21.
  • a male screw 31g to which the fixing nut 50 is screwed is formed on the outer peripheral surface at the tip of the first small diameter portion 31a.
  • the second small diameter portion 31b is formed coaxially with the first small diameter portion 31a in the axial direction, and forms a step portion 31h between the first small diameter portion 31a and the first small diameter portion 31a.
  • An end surface of the plate 40 through which the first small diameter portion 31 a is inserted comes into contact with the step portion 31 h, and the step portion 31 h sandwiches the plate 40 between the fixing nut 50.
  • the large-diameter portion 31 c is formed coaxially with the second small-diameter portion 31 b in the axial direction and is in contact with the coil assembly 33 and the second core 32.
  • the second core 32 of the piston core 30 has a columnar large diameter portion 32a and a columnar small diameter portion 32b formed to have a smaller diameter than the large diameter portion 32a.
  • the large diameter portion 32 a has an end surface 32 c that faces the fluid chamber 12.
  • the small diameter portion 32b is formed coaxially with the large diameter portion 32a continuously in the axial direction.
  • a plurality of tool holes 32d are formed in the end surface 32c of the large diameter portion 32a.
  • the tool holes 32d are holes into which tools are fitted when the piston 20 is screwed onto the piston rod 21, and are formed at intervals of 90 °.
  • the second core 32 is formed of a magnetic material in the same manner as the first core 31.
  • the coil assembly 33 of the piston core 30 includes a cylindrical coil mold part 33b in which a coil 33a is provided, a columnar part 33d fitted to the first core 31, and a radially inward direction from one end of the coil mold part 33b. And a pair of connecting portions 33c that extend linearly and connect the coil mold portion 33b and the cylindrical portion 33d.
  • the coil assembly 33 is formed by molding a resin in a state where the coil 33a is inserted.
  • the coil mold portion 33b is formed so that the inner diameter is substantially the same as the outer diameter of the small diameter portion 32b of the second core 32, and is fitted to the outer peripheral surface of the small diameter portion 32b.
  • the coil mold part 33 b and the connecting part 33 c are sandwiched between the first and second cores 31 and 32.
  • the cylindrical part 33d is located on the opposite side to the coil mold part 33b with respect to the connecting part 33c.
  • the cylindrical portion 33d has an outer diameter that is substantially the same as the inner diameter of the large-diameter portion 31c of the first core 31, and is fitted to the large-diameter portion 31c.
  • the tip 33e of the cylindrical portion 33d is inserted into the through hole 21c of the piston rod 21.
  • An O-ring 34 is provided on the outer peripheral side of the distal end portion 33e of the cylindrical portion 33d.
  • the O-ring 34 is compressed in the axial direction by the large diameter portion 31 c of the first core 31 and the piston rod 21, and is compressed in the radial direction by the tip portion 33 e of the coil assembly 33 and the piston rod 21. This prevents the magnetorheological fluid flowing between the piston rod 21 and the first core 31 or between the first core 31 and the coil assembly 33 from leaking into the through hole 21 c of the piston rod 21.
  • the piston core 30 is formed by being divided into three members of the first core 31, the second core 32, and the coil assembly 33. Therefore, it is only necessary to form only the coil assembly 33 provided with the coil 33 a by molding and to sandwich the coil assembly 33 between the first core 31 and the second core 32.
  • the piston core 30 formed by dividing into three members can easily form the piston core 30 as compared with the case where the piston core 30 is formed as a single body and the molding operation is performed.
  • the first core 31 is fixed to the piston rod 21 by screwing the female screw 31f and the male screw 21d, but the coil assembly 33 and the second core 32 are only fitted in the axial direction.
  • the second core 32 and the coil assembly 33 are fixed so as to be pressed against the first core 31. Therefore, the piston core 30 can be easily assembled.
  • the outer diameter of the large diameter portion 32 a and the coil mold portion 33 b of the second core 32 is formed to be the same as the large diameter portion 31 c of the first core 31. Since the outer diameters of the large diameter portions 31c and 32a and the coil mold portion 33b are the same, in the following, the portion composed of the large diameter portions 31c and 32a and the coil mold portion 33b is referred to as the “large diameter portion 30a” of the piston core 30. Called.
  • the flux ring 35 of the piston 20 is made of a magnetic material.
  • One end 35a of the flux ring 35 is provided with an annular recess 35e recessed in the axial direction.
  • the other end 35b of the flux ring 35 is formed so as to be flush with the end surface 32c of the large diameter portion 32a.
  • the flux ring 35 is formed so that the outer diameter is substantially the same as the inner diameter of the cylinder 10, and the inner diameter is larger than the outer diameter of the large-diameter portion 30 a of the piston core 30. Accordingly, an annular gap is formed between the inner peripheral surface 35c of the flux ring 35 and the outer peripheral surface 30b of the large diameter portion 30a of the piston core 30 over the entire length in the axial direction. This gap functions as the main flow path 22 through which the magnetorheological fluid flows.
  • the coil mold part 33 b faces the main flow path 22. Therefore, the magnetic field generated by the coil 33a acts on the magnetorheological fluid flowing through the main flow path 22. That is, the main flow path 22 functions as a magnetic gap through which the magnetic flux generated around the coil 33a passes.
  • the coil 33a forms a magnetic field by a current supplied from the outside.
  • the strength of the magnetic field increases as the current supplied to the coil 33a increases.
  • a current is supplied to the coil 33a to form a magnetic field, the apparent viscosity of the magnetorheological fluid flowing through the main flow path 22 changes.
  • the viscosity of the magnetorheological fluid increases as the magnetic field generated by the coil 33a increases.
  • a pair of wires (not shown) for supplying a current to the coil 33a is routed inside the connecting portion 33c and the cylindrical portion 33d.
  • the pair of wires are drawn from the tip of the cylindrical portion 33 d and passed through the through hole 21 c of the piston rod 21.
  • a bypass channel 23 is formed so as to sandwich the coil 33a between the piston core 30 and the main channel 22.
  • the bypass channel 23 is a through-hole penetrating the piston core 30 in the axial direction, and two bypass channels 23 are formed at intervals of 180 °.
  • the bypass flow path 23 is provided at a position where the influence of the magnetic field generated by the coil 33 a is smaller than that of the main flow path 22.
  • the number of bypass channels 23 and the arrangement of the bypass channels 23 are not limited to this, and can be arbitrarily set according to required attenuation characteristics, workability, and the like.
  • a single bypass channel 23 may be provided near the axial center of the piston core 30.
  • the bypass channel 23 is a hole having a circular cross section having a first through hole 23 a that penetrates the first core 31 and a second through hole 23 b that penetrates the second core 32.
  • the first through hole 23a and the second through hole 23b are formed to have substantially the same diameter.
  • the first through hole 23 a and the second through hole 23 b are formed avoiding the connecting portion 33 c of the coil assembly 33.
  • a housing hole 23c having an inner diameter larger than that of the other part is formed in a part of the second through hole 23b.
  • One end of the accommodation hole 23 c opens to the end surface 32 e of the second core 32 that contacts the end surface 31 d of the first core 31.
  • a step portion 23d is formed on the inner peripheral surface of the second through hole 23b.
  • a cylindrical temperature compensation unit 60 that changes the flow passage area of the bypass flow passage 23 by being deformed according to the temperature of the magnetorheological fluid is inserted into the accommodation hole 23c. The temperature compensation unit 60 will be described in detail later.
  • the flow passage area in the second through hole 23b is determined by the size of the flow passage defined in the accommodation hole 23c by the temperature compensation unit 60, and this flow passage area is obtained when the temperature compensation unit 60 is deformed. Is set to be smaller than the flow path area of the first through hole 23a. Therefore, the attenuation characteristic when the piston 20 moves is determined by the flow passage area of the second through hole 23b, and the hole diameter of the first through hole 23a does not affect the attenuation characteristic.
  • Two of the above-mentioned four tool holes 32d formed on the end face 32c of the second core 32 are formed at the end of the second through hole 23b.
  • the tool hole 32d is shared with the second through hole 23b.
  • the plate 40 is an annular flat plate member made of a nonmagnetic material.
  • the outer peripheral surface 40b which is an outer edge is press-fitted into the annular recess 35e of the flux ring 35, so that the plate 40 is accommodated in the annular recess 35e and supports the flux ring 35.
  • the plate 40 is formed with a plurality of flow paths 24 that are through holes communicating with the main flow path 22.
  • the flow paths 24 are formed in an arc shape and are arranged at equiangular intervals. Specifically, four flow paths 24 are formed at 90 ° intervals.
  • the flow path 24 is not limited to an arc shape, and may be a circular through hole, for example.
  • An annular gap is formed between the plate 40 and the large diameter part 31 c of the first core 31.
  • This gap functions as a bypass branch 25 that branches and guides the magnetorheological fluid flowing from the channel 24 into the main channel 22 and the bypass channel 23. Since the bypass branch path 25 is formed in an annular shape around the second small diameter portion 31b, it is not necessary to align the circumferential positions of the flow path 24 and the bypass flow path 23 when the piston 20 is assembled, and the piston 20 can be easily Can be assembled.
  • the plate 40 is formed with a through hole 40a into which the first small diameter portion 31a of the first core 31 is fitted. By fitting the first small diameter portion 31a into the through hole 40a, the coaxiality between the plate 40 and the first core 31 is ensured. As a result, the plate 40 defines the distance (the width of the main flow path 22) between the inner peripheral surface 35c of the flux ring 35 and the outer peripheral surface 30b of the large diameter portion 30a.
  • the plate 40 is pressed and clamped against the step portion 31h by the fastening force of the fixing nut 50 with respect to the first small diameter portion 31a of the piston core 30.
  • the position of the axial direction with respect to the piston core 30 of the flux ring 35 fixed to the plate 40 will be prescribed
  • the fixing nut 50 is formed in a substantially cylindrical shape, and is attached to the outer periphery of the first small diameter portion 31a of the piston core 30.
  • the fixing nut 50 is in contact with the plate 40 at the tip 50a.
  • the fixing nut 50 is formed with an internal thread 50c that is engaged with the external thread 31g of the first core 31 on the inner periphery of the base end 50b. Thereby, the fixing nut 50 is screwed to the first small diameter portion 31a.
  • the flux ring 35 and the piston core 30 are coupled via the plate 40 provided on the one end 35a side of the flux ring 35 so that the center axis of the flux ring 35 and the center axis of the piston core 30 coincide with each other. Is done. Further, the axial position of the flux ring 35 with respect to the piston core 30 is defined by the plate 40. For this reason, it is not necessary to provide the member which couple
  • the main flow path 22 is continuously opened in an annular shape with respect to the fluid chamber 12. As a result, the flow resistance of the main flow path 22 is reduced, and the resistance imparted to the magnetorheological fluid passing through the main flow path 22 can be reduced.
  • FIG. 2 is a sectional view taken along line II-II in FIG. In FIG. 2, members other than the piston 20 are omitted for explanation.
  • FIG. 3 is an enlarged view in which a portion indicated by III in FIG. 2 is enlarged.
  • the temperature compensation unit 60 inserted into the accommodation hole 23 c includes a thermal expansion member 61 having a large coefficient of thermal expansion, and a protection member 62 that covers the surface of the thermal expansion member 61.
  • the thermal expansion member 61 is formed of a material having a larger coefficient of thermal expansion than the second core 32, for example, a resin material such as polyethylene and polyethylene terephthalate, or a metal material such as aluminum.
  • the protective member 62 is provided to prevent the thermal expansion member 61 made of resin from being in direct contact with the magnetorheological fluid and being worn by particles contained in the magnetorheological fluid.
  • the protection member 62 is formed of a wear-resistant material, for example, a metal material such as stainless steel.
  • the protection member 62 does not need to be provided on all surfaces of the thermal expansion member 61, and may be provided on a portion where the magnetorheological fluid mainly circulates. If the thermal expansion member 61 is made of metal and is not likely to be worn by the magnetorheological fluid, the protection member 62 may not be provided. Even when a magnetorheological fluid is not used as the working fluid, particles such as iron powder may be present in the working fluid, and thus it is preferable to provide the protective member 62.
  • the thermal expansion member 61 is a member having a C-shaped cross section that is inserted in the axial direction along the accommodation hole 23c.
  • the thermal expansion member 61 is disposed so as to contact the stepped portion 23d and the end surface 31d of the first core 31 in the axial direction. For this reason, the movement of the thermal expansion member 61 in the axial direction is limited by the step portion 23d and the end surface 31d.
  • the outer peripheral surface of the thermal expansion member 61 abuts on the inner peripheral surface of the accommodation hole 23c, the outward movement in the radial direction is limited by the inner peripheral surface of the accommodation hole 23c.
  • the thermal expansion member 61 expands radially inward and circumferentially where movement is not restricted when the temperature of the magnetorheological fluid increases.
  • the thermal expansion member 61 expands radially inward and circumferentially, which is a direction orthogonal to the bypass flow path 23, the flow area of the second through hole 23b is reduced, and the flow resistance of the bypass flow path 23 is increased. To do.
  • the thermal expansion member 61 contracts and the flow path area of the second through hole 23b increases. As a result, the flow resistance of the bypass flow path 23 decreases.
  • the protective member 62 is an elastic body having a force that presses the thermal expansion member 61 radially outward so that the flow passage area of the second through hole 23b is quickly expanded. It may be formed.
  • the protection member 62 has a C-shaped main body 62a provided along the inner peripheral surface of the thermal expansion member 61, and an end extending radially outward from the opening end of the main body 62a. 62b.
  • the radial length of the end portion 62b is such that the outer diameter side end of the end portion 62b is located radially outside the second through-hole 23b even when the thermal expansion member 61 is most expanded.
  • the outer diameter side end of the end portion 62b is set so as not to contact the inner peripheral surface of the accommodation hole 23c.
  • the assembly of the temperature compensation unit 60 to the piston 20 is performed before the piston core 30 is assembled. Specifically, the temperature compensation unit 60 is inserted into the accommodation hole 23c formed in the second core 32 until one end thereof comes into contact with the stepped portion 23d. Then, the end face 32e of the second core 32 into which the temperature compensation unit 60 is inserted is pressed against the end face 31d of the first core 31, and the coil assembly 33 is sandwiched between the first core 31 and the second core 32. The piston core 30 is assembled. At this time, the temperature compensation unit 60 is restricted from moving in the axial direction by the step portion 23d and the end surface 31d, and is assembled in the accommodation hole 23c.
  • the temperature compensation unit 60 is assembled to the piston 20 by a very simple method of insertion into the accommodation hole 23c.
  • the position where the temperature compensation unit 60 is inserted that is, the position where the accommodation hole 23c is formed is not limited to the second core 32, but may be the first core 31 where the bypass flow path 23 is formed.
  • the accommodation hole 23c may be formed across a plurality of members.
  • the shock absorber 100 expands and contracts and the piston rod 21 advances and retreats with respect to the cylinder 10, the magnetorheological fluid passes through the flow path 24 and the bypass branch path 25 formed in the plate 40 and the main flow path 22 and the bypass flow path. 23. Thereby, the piston 20 slides in the cylinder 10 as the magnetorheological fluid flows between the fluid chamber 11 and the fluid chamber 12.
  • the first core 31, the second core 32, and the flux ring 35 formed of a magnetic material constitute a magnetic path that guides a magnetic flux generated around the coil 33a.
  • the plate 40 is formed of a nonmagnetic material, the main flow path 22 between the piston core 30 and the flux ring 35 becomes a magnetic gap through which the magnetic flux generated around the coil 33a passes.
  • the magnetic field of the coil 33a acts on the magnetorheological fluid flowing through the main flow path 22 during the expansion / contraction operation of the shock absorber 100.
  • the adjustment of the damping force generated by the shock absorber 100 is performed by changing the amount of current supplied to the coil 33a and changing the strength of the magnetic field acting on the magnetorheological fluid flowing through the main flow path 22. Specifically, as the current supplied to the coil 33a increases, the strength of the magnetic field generated around the coil 33a increases. Therefore, the viscosity of the magnetorheological fluid flowing through the main flow path 22 increases, and the damping force generated by the shock absorber 100 increases.
  • the bypass flow path 23 is provided in a place that is not easily affected by the magnetic field of the coil 33a. For this reason, even if the energization amount to the coil 33a is changed, the viscosity of the magnetorheological fluid flowing through the bypass passage 23 does not change so much. As a result, the pressure fluctuation that occurs when the damping force is changed by changing the amount of current supplied to the coil 33a is alleviated by providing the bypass flow path 23.
  • the temperature compensation unit 60 expands, the flow area of the second through hole 23b is decreased, and the flow resistance of the bypass flow path 23 is increased. That is, the temperature compensation unit 60 acts to suppress a decrease in damping force when the temperature of the magnetorheological fluid is high.
  • the temperature compensation unit 60 contracts, increasing the flow path area of the second through hole 23b and decreasing the flow resistance of the bypass flow path 23. That is, the temperature compensation unit 60 acts to suppress an increase in damping force when the temperature of the magnetorheological fluid is low.
  • the viscosity of the magnetorheological fluid flowing through the bypass channel 23 is caused by both the magnetic force and the temperature. Change. For this reason, for example, when the viscosity of the magnetic viscous fluid increases when the temperature of the magnetic viscous fluid increases and the flow resistance of the bypass channel 23 increases, the damping force decreases due to the increased temperature of the magnetic viscous fluid. There is a possibility that a damping force larger than the damping force necessary to compensate for the above will be generated in the bypass channel 23.
  • the bypass flow path 23 in which the temperature compensation unit 60 is inserted is provided at a position where the influence of the magnetic field generated by the coil 33a is smaller than that of the main flow path 22. For this reason, the viscosity of the magnetorheological fluid flowing through the bypass flow path 23 changes substantially only by temperature. That is, in the bypass channel 23, the flow resistance is increased or decreased with respect to the magnetorheological fluid whose viscosity changes due to temperature alone. As a result, it is possible to generate a sufficient damping force in the bypass flow path 23 to compensate for a change in the damping force due to a viscosity change due to a temperature change.
  • the temperature compensation unit 60 by providing the temperature compensation unit 60, the change in the damping force of the shock absorber 100 due to the viscosity change of the magnetorheological fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
  • the temperature compensation unit 60 that is deformed according to the temperature of the magnetorheological fluid is inserted into the bypass passage 23 formed through the piston core 30.
  • the bypass flow path 23 into which the temperature compensation unit 60 is inserted is a simple through hole, it can be easily formed. As a result, an increase in manufacturing cost of the shock absorber 100 can be suppressed.
  • the temperature compensation unit 60 inserted into the bypass channel 23 is deformed in a direction perpendicular to the bypass channel 23 according to the temperature of the magnetorheological fluid, and changes the flow resistance of the bypass channel 23. For this reason, the change of the damping force of the shock absorber 100 due to the viscosity change of the magnetorheological fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
  • FIG. 4 is a cross-sectional view corresponding to FIG. 3 of the above embodiment.
  • the cross-sectional shape of the accommodation hole 23c is circular.
  • the cross-sectional shape of the accommodation hole 223c in which the temperature compensation unit 260 is accommodated may be rectangular.
  • the cross-sectional shape of the accommodation hole 223c formed in a part of the second through hole 23b is formed in a rectangle having a long side whose length is longer than the diameter of the other part.
  • Two temperature compensation portions 260 having a rectangular cross-sectional shape are disposed in the housing hole 223c so as to face each other.
  • the flow passage area in the second through hole 23b is determined by the size of the flow passage defined by the two temperature compensation portions 260 and the accommodation hole 223c. This flow passage area is obtained when the temperature compensation portion 260 is deformed. Even if it exists, it sets so that it may become smaller than the flow-path area of the 1st through-hole 23a. Therefore, as in the above embodiment, the damping characteristic when the piston 20 moves is determined by the flow passage area of the second through hole 23b, and the hole diameter of the first through hole 23a does not affect the damping characteristic. .
  • the temperature compensation unit 260 includes a thermal expansion member 261 having a large coefficient of thermal expansion, and a protection member 262 that covers the surface of the thermal expansion member 261.
  • the thermal expansion member 261 and the protection member 262 are formed of the same material as the thermal expansion member 61 and the protection member 62 in the above embodiment.
  • the thermal expansion member 261 is disposed in the accommodation hole 223c so as to contact the stepped portion 223d and the end surface 31d of the first core 31 in the axial direction, similarly to the thermal expansion member 61 of the above embodiment. For this reason, the movement of the thermal expansion member 261 in the axial direction is limited by the step portion 223d and the end surface 31d. Further, since the thermal expansion member 261 is disposed in the accommodation hole 223c having a rectangular cross-sectional shape, the movement of the thermal expansion member 261 is allowed only in the direction orthogonal to the accommodation hole 223c.
  • the thermal expansion member 261 expands in a direction orthogonal to the accommodation hole 223c where movement is not restricted when the temperature of the magnetorheological fluid increases. As the thermal expansion member 261 expands, the flow passage area of the second through hole 23b decreases, and the flow resistance of the bypass flow passage 23 increases.
  • the thermal expansion member 261 contracts, the thermal expansion member 261 is pressed in the direction of separating the two thermal compensation members 260 so that the flow passage area of the second through hole 23b is quickly expanded.
  • An elastic body 263 that exerts an urging force is provided.
  • the elastic body 263 also has a function of preventing the temperature compensation unit 260 from dropping from the accommodation hole 223c or tilting in the accommodation hole 223c.
  • the number of temperature compensation units 260 is not limited to two, and may be one. Also in this case, it is preferable to provide the elastic body 263 so that the flow passage area of the second through hole 23b is quickly expanded when the temperature compensation unit 260 contracts.
  • the cross-sectional shape of the accommodation hole 223c is not limited to a rectangle, and the length in the longitudinal direction is longer than the diameters of the first through hole 23a and the second through hole 23b, and between the second through hole 23b and the accommodation hole 223c. If the step 223d is formed, it may be an ellipse or a rounded rectangle.
  • the temperature compensation unit 260 that deforms according to the temperature of the magnetorheological fluid is inserted into the bypass channel 23 that is formed through the piston core 30 in the above modification.
  • the bypass flow path 23 into which the temperature compensation unit 260 is inserted is a through hole and can be easily formed. As a result, an increase in manufacturing cost of the shock absorber 100 can be suppressed.
  • the temperature compensation unit 260 inserted into the bypass channel 23 is deformed in a direction orthogonal to the bypass channel 23 according to the temperature of the magnetorheological fluid, and changes the flow resistance of the bypass channel 23. For this reason, the change of the damping force of the shock absorber 100 due to the viscosity change of the magnetorheological fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
  • the shock absorber 100 is connected to the cylinder 10 in which the working fluid is sealed, the piston 20 that is slidably disposed in the cylinder 10, and that defines a pair of fluid chambers 11 and 12 in the cylinder 10, and the piston 20.
  • a piston rod 21 extending to the outside of the cylinder 10, and the piston 20 communicates with the pair of fluid chambers 11 and 12, and the working fluid circulates by the movement of the piston 20 and resists the circulated working fluid.
  • Temperature compensation units 60 and 260 that change the flow channel area of the bypass flow channel 23 by being deformed in a direction orthogonal to the bypass flow channel 23.
  • the temperature compensation units 60 and 260 that are deformed according to the temperature of the working fluid are inserted into the bypass channel 23 that is formed through the piston core 30.
  • the bypass flow path 23 into which the temperature compensation parts 60 and 260 are inserted is a simple through hole, it can be easily formed. As a result, an increase in manufacturing cost of the shock absorber 100 can be suppressed.
  • the temperature compensation units 60 and 260 inserted into the bypass channel 23 are deformed in a direction orthogonal to the bypass channel 23 according to the temperature of the working fluid, and change the flow resistance of the bypass channel 23. For this reason, the change in the damping force of the shock absorber 100 due to the change in the viscosity of the working fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the energization amount to the coil 33a regardless of the temperature change of the working fluid.
  • the temperature compensation units 60 and 260 include resin thermal expansion members 61 and 261 and metal protection members 62 and 262 that cover at least a part of the surface of the thermal expansion members 61 and 261.
  • the protective members 62 and 262 that cover the surfaces of the thermal expansion members 61 and 261 are disposed, and the resin thermal expansion members 61 and 261 are prevented from coming into direct contact with the working fluid. For this reason, it can suppress that the resin-made thermal expansion members 61 and 261 are worn by the working fluid.
  • the bypass flow path 23 is a hole having a circular cross section, and the thermal expansion member 61 is formed in a C-shaped cross section, and is provided so that the outer peripheral surface is in contact with the inner peripheral surface of the bypass flow path 23.
  • the member 62 is provided so as to cover at least a part of the inner peripheral surface of the thermal expansion member 61.
  • the thermal expansion member 61 inserted into the bypass channel 23 is formed in a C-shaped cross section. For this reason, when the temperature of the working fluid increases, the thermal expansion member 61 expands inward in the radial direction where movement is not limited. As a result, the flow path area of the bypass flow path 23 changes according to the temperature of the working fluid, so that the flow resistance of the bypass flow path 23 can be changed according to the temperature of the working fluid. Further, a protective member 62 is provided on the inner peripheral surface side of the thermal expansion member 61 through which the working fluid flows. For this reason, it is possible to prevent the resin thermal expansion member 61 from coming into direct contact with the working fluid, and to prevent the thermal expansion member 61 from being worn by the working fluid.
  • the working fluid is a magnetorheological fluid
  • the piston 20 has a piston core 30 attached to the end of the piston rod 21 and provided with a coil 33a on the outer periphery, and a flux ring 35 surrounding the outer periphery of the piston core 30.
  • the main flow path 22 is defined by the outer periphery of the piston core 30 and the inner periphery of the flux ring 35, and the bypass flow path 23 is formed in the piston core 30 so as to sandwich the coil 33 a between the main flow path 22.
  • the bypass flow path 23 in which the temperature compensation units 60 and 260 are inserted is provided at a position where the influence of the magnetic field generated by the coil 33a is smaller than that of the main flow path 22.
  • the temperature compensation units 60 and 260 are suppressed from being affected by the magnetic field generated by the coil 33a, it is possible to compensate for a change in damping force due to a viscosity change due to a temperature change. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
  • a pair of wires for supplying a current to the coil 33a passes through the inner periphery of the piston rod 21. Therefore, it is possible to eliminate the ground for allowing the current applied to the coil 33a to escape to the outside.
  • only one wire for applying a current to the coil 33a may pass through the inside of the piston rod 21 and be grounded to the outside through the piston rod 21 itself.
  • the temperature compensation units 60 and 260 are not limited to the shock absorber 100 using a magnetorheological fluid, and can be applied to a throttle channel of a general shock absorber using hydraulic oil.
  • the cross-sectional area of the flow path can be changed according to the temperature by a simple configuration in which a temperature compensation unit that deforms according to the temperature of the hydraulic oil is inserted into the flow path. As a result, it is possible to compensate for the change in the damping force of the shock absorber caused by the change in the viscosity of the hydraulic oil due to the temperature change.

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Fluid-Damping Devices (AREA)

Abstract

A damper 100 is provided with: a cylinder 10 in which an operating fluid is sealed; a piston 20 disposed in a slidable manner within the cylinder 10; and a piston rod 21 connected to the piston 20. The piston 20 has: a main flow passage 22 which provides communication between a pair of fluid chambers 11, 12, allows an operating fluid to flow therethrough when the piston 20 moves, and provides resistance to an operating fluid flowing therethrough; a bypass flow passage 23 provided parallel to the main flow passage 22 and providing communication between the pair of fluid chambers 11, 12; and a temperature compensation section 60, 260 which is inserted in the bypass flow passage 23 and which, according to the temperature of an operating fluid, deforms in the direction perpendicular to the bypass flow passage 23, thereby changing the flow passage area of the bypass flow passage 23.

Description

緩衝器Shock absorber
　本発明は、緩衝器に関するものである。 The present invention relates to a shock absorber.
　自動車等の車両に搭載される緩衝器として、磁気粘性流体が通過する流路に磁界を作用させ、磁気粘性流体の見かけの粘度を変化させることによって、減衰力を変化させるものがある。ＪＰ２００９－２２８８６１Ａには、外周にコイルが巻回されたピストンコアと、ピストンコアの外周に配置されたピストンリングと、を備えるピストンアッセンブリがシリンダ内を摺動する際に、ピストンコアとピストンリングとの間に形成された流路を磁気粘性流体が通過する緩衝器が開示されている。 Some shock absorbers mounted on vehicles such as automobiles change the damping force by applying a magnetic field to the flow path through which the magnetorheological fluid passes to change the apparent viscosity of the magnetorheological fluid. JP2009-228861A includes a piston core, a piston ring, and a piston core that includes a piston core having a coil wound around the outer periphery and a piston ring disposed on the outer periphery of the piston core. A shock absorber in which a magnetorheological fluid passes through a flow path formed between the two is disclosed.
　磁気粘性流体を含む緩衝器の作動流体は、一般的に、温度の変化によって粘度が変化する。このため、ＪＰ２００９－２２８８６１Ａに記載される緩衝器では、磁気粘性流体の温度が変化する場合であっても安定した減衰力を得るために、バイパス流路に温度補償バルブを設けている。 The working fluid of the shock absorber including the magnetorheological fluid generally changes in viscosity due to a change in temperature. For this reason, in the shock absorber described in JP2009-228861A, a temperature compensation valve is provided in the bypass flow path in order to obtain a stable damping force even when the temperature of the magnetorheological fluid changes.
　しかしながら、ＪＰ２００９－２２８８６１Ａに記載される緩衝器では、バイパス流路に温度補償バルブを設けるために、バイパス流路は直交する複数の孔を接続させることによって構成される。このため、バイパス流路を加工する工数が増加し、結果として、製造コストが上昇するおそれがある。 However, in the shock absorber described in JP2009-228861A, in order to provide a temperature compensation valve in the bypass channel, the bypass channel is configured by connecting a plurality of orthogonal holes. For this reason, the man-hour which processes a bypass flow path increases, and there exists a possibility that manufacturing cost may rise as a result.
　本発明は、簡素な構成により、作動流体の温度変化に関わらず要求される減衰力を発生させることを目的とする。 An object of the present invention is to generate a required damping force regardless of a temperature change of a working fluid with a simple configuration.
　本発明のある態様によれば、緩衝器は、作動流体が封入されるシリンダと、前記シリンダ内に摺動自在に配置され、前記シリンダ内に一対の流体室を画成するピストンと、前記ピストンに連結されて前記シリンダの外部へ延在するピストンロッドと、を備え、前記ピストンは、一対の前記流体室を連通し、前記ピストンの移動によって作動流体が流通するとともに、流通する作動流体に抵抗を付与するメイン流路と、前記メイン流路と並列に設けられ、一対の前記流体室を連通するバイパス流路と、前記バイパス流路に挿入され、作動流体の温度に応じて前記バイパス流路に直交する方向に変形することによって前記バイパス流路の流路面積を変化させる温度補償部と、を有する。 According to an aspect of the present invention, the shock absorber includes a cylinder in which a working fluid is sealed, a piston that is slidably disposed in the cylinder, and that defines a pair of fluid chambers in the cylinder, and the piston A piston rod connected to the cylinder and extending to the outside of the cylinder. The piston communicates with the pair of fluid chambers, and the working fluid circulates by the movement of the piston and resists the circulated working fluid. A main flow path that provides the flow path, a bypass flow path that is provided in parallel with the main flow path and communicates with a pair of the fluid chambers, and is inserted into the bypass flow path, and the bypass flow path according to the temperature of the working fluid And a temperature compensation unit that changes the flow passage area of the bypass flow passage by being deformed in a direction orthogonal to the first flow passage.
図１は、本発明の実施形態に係る磁気粘性流体緩衝器の正面の断面図である。FIG. 1 is a front sectional view of a magnetorheological fluid shock absorber according to an embodiment of the present invention. 図２は、図１のII－II線に沿う断面図である。FIG. 2 is a sectional view taken along line II-II in FIG. 図３は、図２のIII部の拡大図である。FIG. 3 is an enlarged view of a portion III in FIG. 図４は、本発明の実施形態の変形例に係る磁気粘性流体緩衝器の拡大図である。FIG. 4 is an enlarged view of a magnetorheological fluid shock absorber according to a modification of the embodiment of the present invention.
　以下、図面を参照して、本発明の実施形態について説明する。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
　まず、図１を参照して、本発明の実施形態に係る緩衝器について説明する。 First, a shock absorber according to an embodiment of the present invention will be described with reference to FIG.
　本実施形態では、緩衝器が、磁界の作用によって見かけの粘度が変化する磁気粘性流体を作動流体として用いることで減衰係数が変化可能な緩衝器１００である場合について説明する。緩衝器１００は、例えば、自動車等の車両において車体と車軸との間に介装される。緩衝器１００は、伸縮作動によって車体の振動を抑える減衰力を発生する。 In the present embodiment, a case will be described in which the shock absorber is a shock absorber 100 whose damping coefficient can be changed by using a magnetorheological fluid whose apparent viscosity is changed by the action of a magnetic field as a working fluid. The shock absorber 100 is interposed, for example, between a vehicle body and an axle in a vehicle such as an automobile. The shock absorber 100 generates a damping force that suppresses vibration of the vehicle body by an expansion and contraction operation.
　緩衝器１００は、内部に磁気粘性流体が封入されるシリンダ１０と、シリンダ１０内に摺動自在に配置されるピストン２０と、ピストン２０に連結されてシリンダ１０の外部へ延在するピストンロッド２１と、を備える。ピストンロッド２１は、ピストン２０の摺動に伴ってシリンダ１０に対して進退する。 The shock absorber 100 includes a cylinder 10 in which a magnetorheological fluid is sealed, a piston 20 that is slidably disposed in the cylinder 10, and a piston rod 21 that is connected to the piston 20 and extends to the outside of the cylinder 10. And comprising. The piston rod 21 moves forward and backward with respect to the cylinder 10 as the piston 20 slides.
　シリンダ１０は、有底円筒状に形成される。シリンダ１０内に封入される磁気粘性流体は、磁界の作用によって見かけの粘度が変化するものであり、油等の液体中に強磁性を有する微粒子を分散させた液体である。磁気粘性流体の粘性は、作用する磁界の強さに応じて変化し、磁界の影響がなくなると元の状態に戻る。 The cylinder 10 is formed in a bottomed cylindrical shape. The magnetorheological fluid sealed in the cylinder 10 has an apparent viscosity that is changed by the action of a magnetic field, and is a liquid in which fine particles having ferromagnetism are dispersed in a liquid such as oil. The viscosity of the magnetorheological fluid changes according to the strength of the applied magnetic field, and returns to its original state when the magnetic field is no longer affected.
　シリンダ１０内には、ガスが封入されるガス室（図示省略）が、フリーピストン（図示省略）を介して画成される。ピストンロッド２１の進退によるシリンダ１０内の容積変化は、ガス室によって補償される。 In the cylinder 10, a gas chamber (not shown) in which gas is sealed is defined via a free piston (not shown). The volume change in the cylinder 10 due to the advance / retreat of the piston rod 21 is compensated by the gas chamber.
　ピストン２０は、シリンダ１０内に流体室１１と流体室１２とを画成する。流体室１１と流体室１２とは、ピストン２０に形成されるメイン流路２２及びバイパス流路２３を通じて連通する。ピストン２０の構成については、後で詳細に説明する。 The piston 20 defines a fluid chamber 11 and a fluid chamber 12 in the cylinder 10. The fluid chamber 11 and the fluid chamber 12 communicate with each other through a main channel 22 and a bypass channel 23 formed in the piston 20. The configuration of the piston 20 will be described later in detail.
　ピストンロッド２１は、ピストン２０と同軸に形成され、ピストンロッド２１の一端２１ａがピストン２０に固定される。ピストンの他端２１ｂはシリンダ１０の外部に延出する。 The piston rod 21 is formed coaxially with the piston 20, and one end 21 a of the piston rod 21 is fixed to the piston 20. The other end 21 b of the piston extends to the outside of the cylinder 10.
　ピストンロッド２１は、一端２１ａと他端２１ｂとに渡って貫通孔２１ｃが形成される円筒形状である。ピストンロッド２１の外周面には、ピストン２０と螺合する雄ねじ２１ｄが形成される。 The piston rod 21 has a cylindrical shape in which a through hole 21c is formed across one end 21a and the other end 21b. A male screw 21 d that is screwed with the piston 20 is formed on the outer peripheral surface of the piston rod 21.
　ピストン２０は、ピストンロッド２１に取り付けられるピストンコア３０と、ピストンコア３０の外周を取り囲むリング体としての環状のフラックスリング３５と、ピストンコア３０に設けられると共にフラックスリング３５を支持する環状のプレート４０と、ピストンコア３０の外周面に取り付けられプレート４０をピストンコア３０に固定する固定ナット５０と、を有する。 The piston 20 includes a piston core 30 attached to the piston rod 21, an annular flux ring 35 as a ring body surrounding the outer periphery of the piston core 30, and an annular plate 40 provided on the piston core 30 and supporting the flux ring 35. And a fixing nut 50 that is attached to the outer peripheral surface of the piston core 30 and fixes the plate 40 to the piston core 30.
　ピストンコア３０は、コイル３３ａが設けられるコイルアセンブリ３３と、コイルアセンブリ３３を挟持する第１及び第２コア３１，３２と、に分割して形成される。第１及び第２コア３１，３２は、コイルアセンブリ３３を挟持した状態で、一対のボルト（図示省略）によって締結される。 The piston core 30 is formed by being divided into a coil assembly 33 provided with a coil 33a and first and second cores 31 and 32 sandwiching the coil assembly 33. The first and second cores 31 and 32 are fastened by a pair of bolts (not shown) with the coil assembly 33 sandwiched therebetween.
　第１コア３１は、円筒状の第１小径部３１ａと、第１小径部３１ａと比較して大径に形成される円筒状の第２小径部３１ｂと、第２小径部３１ｂと比較して大径に形成される円筒状の大径部３１ｃと、を有する。第１コア３１は、磁性材によって形成される。 The first core 31 has a cylindrical first small-diameter portion 31a, a cylindrical second small-diameter portion 31b formed with a larger diameter than the first small-diameter portion 31a, and a second small-diameter portion 31b. And a cylindrical large-diameter portion 31c formed to have a large diameter. The first core 31 is formed of a magnetic material.
　第１小径部３１ａの内周面には、ピストンロッド２１の雄ねじ２１ｄと螺合する雌ねじ３１ｆが形成される。第１小径部３１ａの雌ねじ３１ｆとピストンロッド２１の雄ねじ２１ｄとの螺合により、第１コア３１がピストンロッド２１に締結される。第１小径部３１ａの先端の外周面には、固定ナット５０が螺合する雄ねじ３１ｇが形成される。 A female screw 31f that is screwed with the male screw 21d of the piston rod 21 is formed on the inner peripheral surface of the first small diameter portion 31a. The first core 31 is fastened to the piston rod 21 by screwing the female screw 31 f of the first small diameter portion 31 a and the male screw 21 d of the piston rod 21. A male screw 31g to which the fixing nut 50 is screwed is formed on the outer peripheral surface at the tip of the first small diameter portion 31a.
　第２小径部３１ｂは、第１小径部３１ａに軸方向に連続して同軸に形成され、第１小径部３１ａとの間に段部３１ｈを形成する。段部３１ｈには、第１小径部３１ａが挿通されるプレート４０の端面が当接し、段部３１ｈは、固定ナット５０との間にプレート４０を挟持する。 The second small diameter portion 31b is formed coaxially with the first small diameter portion 31a in the axial direction, and forms a step portion 31h between the first small diameter portion 31a and the first small diameter portion 31a. An end surface of the plate 40 through which the first small diameter portion 31 a is inserted comes into contact with the step portion 31 h, and the step portion 31 h sandwiches the plate 40 between the fixing nut 50.
　大径部３１ｃは、第２小径部３１ｂに軸方向に連続して同軸に形成され、コイルアセンブリ３３及び第２コア３２と当接する。 The large-diameter portion 31 c is formed coaxially with the second small-diameter portion 31 b in the axial direction and is in contact with the coil assembly 33 and the second core 32.
　ピストンコア３０の第２コア３２は、円柱状の大径部３２ａと、大径部３２ａと比較して小径に形成される円柱状の小径部３２ｂと、を有する。大径部３２ａは、流体室１２に臨む端面３２ｃを有する。小径部３２ｂは、大径部３２ａに軸方向に連続して同軸に形成される。 The second core 32 of the piston core 30 has a columnar large diameter portion 32a and a columnar small diameter portion 32b formed to have a smaller diameter than the large diameter portion 32a. The large diameter portion 32 a has an end surface 32 c that faces the fluid chamber 12. The small diameter portion 32b is formed coaxially with the large diameter portion 32a continuously in the axial direction.
　大径部３２ａの端面３２ｃには複数の工具穴３２ｄが形成される。工具穴３２ｄは、ピストン２０をピストンロッド２１に螺着する際に工具が嵌められる穴であり、９０°間隔で４つ形成される。 A plurality of tool holes 32d are formed in the end surface 32c of the large diameter portion 32a. The tool holes 32d are holes into which tools are fitted when the piston 20 is screwed onto the piston rod 21, and are formed at intervals of 90 °.
　第２コア３２は、第１コア３１と同様に、磁性材によって形成される。 The second core 32 is formed of a magnetic material in the same manner as the first core 31.
　ピストンコア３０のコイルアセンブリ３３は、内部にコイル３３ａが設けられる円筒状のコイルモールド部３３ｂと、第１コア３１に嵌合する円柱部３３ｄと、コイルモールド部３３ｂの一端から径方向内側に向かって直線状に延在し、コイルモールド部３３ｂと円柱部３３ｄとを連結する一対の連結部３３ｃと、を有する。コイルアセンブリ３３は、コイル３３ａが挿入された状態で樹脂をモールドすることで形成される。 The coil assembly 33 of the piston core 30 includes a cylindrical coil mold part 33b in which a coil 33a is provided, a columnar part 33d fitted to the first core 31, and a radially inward direction from one end of the coil mold part 33b. And a pair of connecting portions 33c that extend linearly and connect the coil mold portion 33b and the cylindrical portion 33d. The coil assembly 33 is formed by molding a resin in a state where the coil 33a is inserted.
　コイルモールド部３３ｂは、内径が第２コア３２の小径部３２ｂの外径と略同径に形成され、小径部３２ｂの外周面に嵌合する。コイルモールド部３３ｂ及び連結部３３ｃが第１及び第２コア３１，３２により挟持される。 The coil mold portion 33b is formed so that the inner diameter is substantially the same as the outer diameter of the small diameter portion 32b of the second core 32, and is fitted to the outer peripheral surface of the small diameter portion 32b. The coil mold part 33 b and the connecting part 33 c are sandwiched between the first and second cores 31 and 32.
　円柱部３３ｄは、連結部３３ｃに対してコイルモールド部３３ｂとは反対側に位置する。円柱部３３ｄは外径が第１コア３１の大径部３１ｃの内径と略同径に形成され、大径部３１ｃと嵌合する。 The cylindrical part 33d is located on the opposite side to the coil mold part 33b with respect to the connecting part 33c. The cylindrical portion 33d has an outer diameter that is substantially the same as the inner diameter of the large-diameter portion 31c of the first core 31, and is fitted to the large-diameter portion 31c.
　また、円柱部３３ｄは、先端部３３ｅがピストンロッド２１の貫通孔２１ｃに挿入される。円柱部３３ｄの先端部３３ｅの外周側には、Ｏリング３４が設けられる。 Further, the tip 33e of the cylindrical portion 33d is inserted into the through hole 21c of the piston rod 21. An O-ring 34 is provided on the outer peripheral side of the distal end portion 33e of the cylindrical portion 33d.
　Ｏリング３４は、第１コア３１の大径部３１ｃとピストンロッド２１とによって軸方向に圧縮され、コイルアセンブリ３３の先端部３３ｅとピストンロッド２１とによって径方向に圧縮される。これにより、ピストンロッド２１と第１コア３１との間や、第１コア３１とコイルアセンブリ３３との間に流入した磁気粘性流体がピストンロッド２１の貫通孔２１ｃに漏出することが防止される。 The O-ring 34 is compressed in the axial direction by the large diameter portion 31 c of the first core 31 and the piston rod 21, and is compressed in the radial direction by the tip portion 33 e of the coil assembly 33 and the piston rod 21. This prevents the magnetorheological fluid flowing between the piston rod 21 and the first core 31 or between the first core 31 and the coil assembly 33 from leaking into the through hole 21 c of the piston rod 21.
　このように、ピストンコア３０は、第１コア３１と第２コア３２とコイルアセンブリ３３との３部材に分割して形成される。したがって、コイル３３ａが設けられるコイルアセンブリ３３のみをモールドにて形成し、第１コア３１と第２コア３２との間にコイルアセンブリ３３を挟持すればよい。３部材に分割して形成されるピストンコア３０は、ピストンコア３０を単体で形成してモールド作業を行う場合と比較して、ピストンコア３０を容易に形成することができる。 Thus, the piston core 30 is formed by being divided into three members of the first core 31, the second core 32, and the coil assembly 33. Therefore, it is only necessary to form only the coil assembly 33 provided with the coil 33 a by molding and to sandwich the coil assembly 33 between the first core 31 and the second core 32. The piston core 30 formed by dividing into three members can easily form the piston core 30 as compared with the case where the piston core 30 is formed as a single body and the molding operation is performed.
　ピストンコア３０において、第１コア３１は雌ねじ３１ｆと雄ねじ２１ｄとの螺合によりピストンロッド２１に固定されるが、コイルアセンブリ３３と第２コア３２とは軸方向に嵌められているのみである。一対のボルトを用いることにより、第２コア３２及びコイルアセンブリ３３が第１コア３１に押し付けられるように固定される。したがって、ピストンコア３０を容易に組み立てることができる。 In the piston core 30, the first core 31 is fixed to the piston rod 21 by screwing the female screw 31f and the male screw 21d, but the coil assembly 33 and the second core 32 are only fitted in the axial direction. By using a pair of bolts, the second core 32 and the coil assembly 33 are fixed so as to be pressed against the first core 31. Therefore, the piston core 30 can be easily assembled.
　第２コア３２の大径部３２ａ及びコイルモールド部３３ｂは、外径が第１コア３１の大径部３１ｃと同径に形成される。大径部３１ｃ，３２ａ及びコイルモールド部３３ｂの外径が同一であるので、以下において、大径部３１ｃ，３２ａ及びコイルモールド部３３ｂからなる部分を、ピストンコア３０の「大径部３０ａ」と称する。 The outer diameter of the large diameter portion 32 a and the coil mold portion 33 b of the second core 32 is formed to be the same as the large diameter portion 31 c of the first core 31. Since the outer diameters of the large diameter portions 31c and 32a and the coil mold portion 33b are the same, in the following, the portion composed of the large diameter portions 31c and 32a and the coil mold portion 33b is referred to as the “large diameter portion 30a” of the piston core 30. Called.
　ピストン２０のフラックスリング３５は、磁性材によって形成される。フラックスリング３５の一端３５ａには、軸方向にくぼむ環状凹部３５ｅが設けられる。フラックスリング３５の他端３５ｂは、大径部３２ａの端面３２ｃと面一となるように形成される。 The flux ring 35 of the piston 20 is made of a magnetic material. One end 35a of the flux ring 35 is provided with an annular recess 35e recessed in the axial direction. The other end 35b of the flux ring 35 is formed so as to be flush with the end surface 32c of the large diameter portion 32a.
　フラックスリング３５は、外径がシリンダ１０の内径と略同径に形成され、内径がピストンコア３０の大径部３０ａの外径よりも大径に形成される。したがって、フラックスリング３５の内周面３５ｃとピストンコア３０の大径部３０ａの外周面３０ｂとの間には、軸方向全長に渡って環状の隙間が形成される。この隙間は、磁気粘性流体が流通するメイン流路２２として機能する。 The flux ring 35 is formed so that the outer diameter is substantially the same as the inner diameter of the cylinder 10, and the inner diameter is larger than the outer diameter of the large-diameter portion 30 a of the piston core 30. Accordingly, an annular gap is formed between the inner peripheral surface 35c of the flux ring 35 and the outer peripheral surface 30b of the large diameter portion 30a of the piston core 30 over the entire length in the axial direction. This gap functions as the main flow path 22 through which the magnetorheological fluid flows.
　コイルモールド部３３ｂは、メイン流路２２に臨む。そのため、コイル３３ａが発生する磁界はメイン流路２２を流れる磁気粘性流体に作用する。つまり、メイン流路２２は、コイル３３ａのまわりに生じる磁束が通過する磁気ギャップとして機能する。 The coil mold part 33 b faces the main flow path 22. Therefore, the magnetic field generated by the coil 33a acts on the magnetorheological fluid flowing through the main flow path 22. That is, the main flow path 22 functions as a magnetic gap through which the magnetic flux generated around the coil 33a passes.
　コイル３３ａは、外部から供給される電流によって磁界を形成する。この磁界の強さは、コイル３３ａに供給される電流が大きくなるほど強くなる。コイル３３ａに電流が供給されて磁界が形成されると、メイン流路２２を流れる磁気粘性流体の見かけの粘度が変化する。磁気粘性流体の粘性は、コイル３３ａによる磁界が強くなるほど高くなる。 The coil 33a forms a magnetic field by a current supplied from the outside. The strength of the magnetic field increases as the current supplied to the coil 33a increases. When a current is supplied to the coil 33a to form a magnetic field, the apparent viscosity of the magnetorheological fluid flowing through the main flow path 22 changes. The viscosity of the magnetorheological fluid increases as the magnetic field generated by the coil 33a increases.
　コイル３３ａへ電流を供給するための一対の配線（図示省略）は、連結部３３ｃ及び円柱部３３ｄの内部に配索される。この一対の配線は、円柱部３３ｄの先端から引き出され、ピストンロッド２１の貫通孔２１ｃに通される。 A pair of wires (not shown) for supplying a current to the coil 33a is routed inside the connecting portion 33c and the cylindrical portion 33d. The pair of wires are drawn from the tip of the cylindrical portion 33 d and passed through the through hole 21 c of the piston rod 21.
　ピストンコア３０には、メイン流路２２との間にコイル３３ａを挟むようにして、バイパス流路２３が形成される。バイパス流路２３は、ピストンコア３０を軸方向に貫通する貫通孔であり、１８０°間隔で２つ形成される。バイパス流路２３は、メイン流路２２と比較してコイル３３ａが発生する磁場の影響が小さい位置に設けられる。バイパス流路２３の数やバイパス流路２３の配置はこれに限定されず、要求される減衰特性や加工性等に応じて任意に設定される。例えば、コイル３３ａが発生する磁場の影響を小さくするために、ピストンコア３０の軸中心寄りに１本のバイパス流路２３を設けた構成としてもよい。 In the piston core 30, a bypass channel 23 is formed so as to sandwich the coil 33a between the piston core 30 and the main channel 22. The bypass channel 23 is a through-hole penetrating the piston core 30 in the axial direction, and two bypass channels 23 are formed at intervals of 180 °. The bypass flow path 23 is provided at a position where the influence of the magnetic field generated by the coil 33 a is smaller than that of the main flow path 22. The number of bypass channels 23 and the arrangement of the bypass channels 23 are not limited to this, and can be arbitrarily set according to required attenuation characteristics, workability, and the like. For example, in order to reduce the influence of the magnetic field generated by the coil 33a, a single bypass channel 23 may be provided near the axial center of the piston core 30.
　バイパス流路２３は、第１コア３１を貫通する第１貫通孔２３ａと、第２コア３２を貫通する第２貫通孔２３ｂと、を有する断面円形状の孔である。第１貫通孔２３ａと第２貫通孔２３ｂとは、略同径に形成される。第１貫通孔２３ａと第２貫通孔２３ｂとは、コイルアセンブリ３３の連結部３３ｃを避けて形成される。 The bypass channel 23 is a hole having a circular cross section having a first through hole 23 a that penetrates the first core 31 and a second through hole 23 b that penetrates the second core 32. The first through hole 23a and the second through hole 23b are formed to have substantially the same diameter. The first through hole 23 a and the second through hole 23 b are formed avoiding the connecting portion 33 c of the coil assembly 33.
　第２貫通孔２３ｂの一部には、他の部分よりも内径が大きい収容孔２３ｃが形成される。収容孔２３ｃの一端は、第１コア３１の端面３１ｄと当接する第２コア３２の端面３２ｅに開口する。第２貫通孔２３ｂに収容孔２３ｃが形成されることによって、第２貫通孔２３ｂの内周面には、段部２３ｄが形成される。収容孔２３ｃには、磁気粘性流体の温度に応じて変形することによってバイパス流路２３の流路面積を変化させる筒状の温度補償部６０が挿入される。温度補償部６０については、後で詳細に説明する。 A housing hole 23c having an inner diameter larger than that of the other part is formed in a part of the second through hole 23b. One end of the accommodation hole 23 c opens to the end surface 32 e of the second core 32 that contacts the end surface 31 d of the first core 31. By forming the accommodation hole 23c in the second through hole 23b, a step portion 23d is formed on the inner peripheral surface of the second through hole 23b. A cylindrical temperature compensation unit 60 that changes the flow passage area of the bypass flow passage 23 by being deformed according to the temperature of the magnetorheological fluid is inserted into the accommodation hole 23c. The temperature compensation unit 60 will be described in detail later.
　第２貫通孔２３ｂにおける流路面積は、温度補償部６０によって収容孔２３ｃ内に画定される流路の大きさによって決定され、この流路面積は、温度補償部６０が変形した場合であっても、第１貫通孔２３ａの流路面積よりも小さくなるように設定される。したがって、ピストン２０が移動する時の減衰特性は、第２貫通孔２３ｂの流路面積によって決定され、第１貫通孔２３ａの穴径は、減衰特性に影響を及ぼさない。 The flow passage area in the second through hole 23b is determined by the size of the flow passage defined in the accommodation hole 23c by the temperature compensation unit 60, and this flow passage area is obtained when the temperature compensation unit 60 is deformed. Is set to be smaller than the flow path area of the first through hole 23a. Therefore, the attenuation characteristic when the piston 20 moves is determined by the flow passage area of the second through hole 23b, and the hole diameter of the first through hole 23a does not affect the attenuation characteristic.
　第２コア３２の端面３２ｃに形成される前述の４つの工具穴３２ｄのうち２つは、第２貫通孔２３ｂの端部に形成される。このように、工具穴３２ｄは、第２貫通孔２３ｂと共用される。 Two of the above-mentioned four tool holes 32d formed on the end face 32c of the second core 32 are formed at the end of the second through hole 23b. Thus, the tool hole 32d is shared with the second through hole 23b.
　プレート４０は、非磁性材によって形成される円環状の平板部材である。プレート４０は、外縁である外周面４０ｂがフラックスリング３５の環状凹部３５ｅに圧入されることによって、環状凹部３５ｅ内に収容され、フラックスリング３５を支持する。 The plate 40 is an annular flat plate member made of a nonmagnetic material. The outer peripheral surface 40b which is an outer edge is press-fitted into the annular recess 35e of the flux ring 35, so that the plate 40 is accommodated in the annular recess 35e and supports the flux ring 35.
　プレート４０には、メイン流路２２に連通する貫通孔である複数の流路２４が形成される。流路２４は、円弧状に形成されて等角度間隔に配置される。具体的には、流路２４は、９０°間隔で４つ形成される。流路２４は、円弧状に限られず、例えば円形の貫通孔であってもよい。 The plate 40 is formed with a plurality of flow paths 24 that are through holes communicating with the main flow path 22. The flow paths 24 are formed in an arc shape and are arranged at equiangular intervals. Specifically, four flow paths 24 are formed at 90 ° intervals. The flow path 24 is not limited to an arc shape, and may be a circular through hole, for example.
　プレート４０と第１コア３１の大径部３１ｃとの間には、環状の空隙が形成される。この空隙は、流路２４から流入した磁気粘性流体をメイン流路２２とバイパス流路２３とに分岐して導くバイパス分岐路２５として機能する。バイパス分岐路２５が第２小径部３１ｂの周りに環状に形成されるので、ピストン２０の組立時に流路２４とバイパス流路２３との周方向の位置を合わせる必要がなく、ピストン２０を容易に組み立てることができる。 An annular gap is formed between the plate 40 and the large diameter part 31 c of the first core 31. This gap functions as a bypass branch 25 that branches and guides the magnetorheological fluid flowing from the channel 24 into the main channel 22 and the bypass channel 23. Since the bypass branch path 25 is formed in an annular shape around the second small diameter portion 31b, it is not necessary to align the circumferential positions of the flow path 24 and the bypass flow path 23 when the piston 20 is assembled, and the piston 20 can be easily Can be assembled.
　プレート４０には、第１コア３１の第１小径部３１ａが嵌合する貫通孔４０ａが形成される。貫通孔４０ａに第１小径部３１ａが嵌合することによって、プレート４０と第１コア３１との同軸度が確保される。その結果、プレート４０により、フラックスリング３５の内周面３５ｃと大径部３０ａの外周面３０ｂとの間の間隔（メイン流路２２の幅）が規定される。 The plate 40 is formed with a through hole 40a into which the first small diameter portion 31a of the first core 31 is fitted. By fitting the first small diameter portion 31a into the through hole 40a, the coaxiality between the plate 40 and the first core 31 is ensured. As a result, the plate 40 defines the distance (the width of the main flow path 22) between the inner peripheral surface 35c of the flux ring 35 and the outer peripheral surface 30b of the large diameter portion 30a.
　また、プレート４０は、ピストンコア３０の第１小径部３１ａに対する固定ナット５０の締結力によって段部３１ｈに押し付けられて挟持される。これにより、プレート４０に固定されるフラックスリング３５のピストンコア３０に対する軸方向の位置が規定されることとなる。 Further, the plate 40 is pressed and clamped against the step portion 31h by the fastening force of the fixing nut 50 with respect to the first small diameter portion 31a of the piston core 30. Thereby, the position of the axial direction with respect to the piston core 30 of the flux ring 35 fixed to the plate 40 will be prescribed | regulated.
　固定ナット５０は、略円筒状に形成され、ピストンコア３０の第１小径部３１ａの外周に取り付けられる。固定ナット５０は、先端部５０ａがプレート４０と当接する。固定ナット５０は、基端部５０ｂの内周に、第１コア３１の雄ねじ３１ｇに螺合する雌ねじ５０ｃが形成される。これにより、固定ナット５０は、第１小径部３１ａに螺着される。 The fixing nut 50 is formed in a substantially cylindrical shape, and is attached to the outer periphery of the first small diameter portion 31a of the piston core 30. The fixing nut 50 is in contact with the plate 40 at the tip 50a. The fixing nut 50 is formed with an internal thread 50c that is engaged with the external thread 31g of the first core 31 on the inner periphery of the base end 50b. Thereby, the fixing nut 50 is screwed to the first small diameter portion 31a.
　このように、フラックスリング３５とピストンコア３０とは、フラックスリング３５の中心軸とピストンコア３０の中心軸とが一致するように、フラックスリング３５の一端３５ａ側に設けられるプレート４０を介して結合される。さらに、ピストンコア３０に対するフラックスリング３５の軸方向の位置は、プレート４０によって規定される。このため、フラックスリング３５の他端３５ｂ側には、フラックスリング３５とピストンコア３０とを結合し、フラックスリング３５の軸方向位置を規定する部材を設ける必要がない。したがって、緩衝器１００のピストン２０の全長を短くすることができる。 Thus, the flux ring 35 and the piston core 30 are coupled via the plate 40 provided on the one end 35a side of the flux ring 35 so that the center axis of the flux ring 35 and the center axis of the piston core 30 coincide with each other. Is done. Further, the axial position of the flux ring 35 with respect to the piston core 30 is defined by the plate 40. For this reason, it is not necessary to provide the member which couple | bonds the flux ring 35 and the piston core 30 and prescribes | regulates the axial direction position of the flux ring 35 in the other end 35b side of the flux ring 35. Therefore, the total length of the piston 20 of the shock absorber 100 can be shortened.
　また、フラックスリング３５の他端３５ｂ側にはフラックスリング３５とピストンコア３０とを結合する部材が配置されないため、メイン流路２２は、流体室１２に対して環状に連続して開口する。この結果、メイン流路２２の流通抵抗が低減され、メイン流路２２を通過する磁気粘性流体に付与される抵抗を低減することができる。 Further, since the member for connecting the flux ring 35 and the piston core 30 is not disposed on the other end 35b side of the flux ring 35, the main flow path 22 is continuously opened in an annular shape with respect to the fluid chamber 12. As a result, the flow resistance of the main flow path 22 is reduced, and the resistance imparted to the magnetorheological fluid passing through the main flow path 22 can be reduced.
　次に、図１から図３を参照して、温度補償部６０について説明する。図２は、図１のＩＩ－ＩＩ線に沿う断面図である。図２では、説明のため、ピストン２０以外の部材については省略して示している。図３は、図２のＩＩＩで示される部分を拡大した拡大図である。 Next, the temperature compensation unit 60 will be described with reference to FIGS. 1 to 3. FIG. 2 is a sectional view taken along line II-II in FIG. In FIG. 2, members other than the piston 20 are omitted for explanation. FIG. 3 is an enlarged view in which a portion indicated by III in FIG. 2 is enlarged.
　図３に示されるように、収容孔２３ｃに挿入される温度補償部６０は、熱膨張率が大きい熱膨張部材６１と、熱膨張部材６１の表面を覆う保護部材６２と、を有する。熱膨張部材６１は、第２コア３２と比較して熱膨張率が大きい材料、例えばポリエチレン及びポリエチレンテレフタレート等の樹脂材料、又はアルミニウム等の金属材料により形成される。 As shown in FIG. 3, the temperature compensation unit 60 inserted into the accommodation hole 23 c includes a thermal expansion member 61 having a large coefficient of thermal expansion, and a protection member 62 that covers the surface of the thermal expansion member 61. The thermal expansion member 61 is formed of a material having a larger coefficient of thermal expansion than the second core 32, for example, a resin material such as polyethylene and polyethylene terephthalate, or a metal material such as aluminum.
　保護部材６２は、特に樹脂製の熱膨張部材６１が磁気粘性流体に直接接触して磁気粘性流体に含まれる粒子等によって摩耗することを防止するために設けられる。このため、保護部材６２は、耐摩耗性を有する材料、例えばステンレス等の金属材料により形成される。保護部材６２は、熱膨張部材６１の全ての面に設けられる必要はなく、磁気粘性流体が主に流通する部分に設けられていればよい。熱膨張部材６１が金属によって形成され、磁気粘性流体によって摩耗するおそれがなければ、保護部材６２は設けられなくてもよい。なお、作動流体として磁気粘性流体を用いない場合であっても、作動流体中には鉄粉等の粒子が存在することがあるため、保護部材６２を設けることが好ましい。 The protective member 62 is provided to prevent the thermal expansion member 61 made of resin from being in direct contact with the magnetorheological fluid and being worn by particles contained in the magnetorheological fluid. For this reason, the protection member 62 is formed of a wear-resistant material, for example, a metal material such as stainless steel. The protection member 62 does not need to be provided on all surfaces of the thermal expansion member 61, and may be provided on a portion where the magnetorheological fluid mainly circulates. If the thermal expansion member 61 is made of metal and is not likely to be worn by the magnetorheological fluid, the protection member 62 may not be provided. Even when a magnetorheological fluid is not used as the working fluid, particles such as iron powder may be present in the working fluid, and thus it is preferable to provide the protective member 62.
　熱膨張部材６１は、収容孔２３ｃに沿って軸方向に挿入される断面Ｃ字状の部材である。熱膨張部材６１は、軸方向において段部２３ｄと第１コア３１の端面３１ｄとに当接するように配置される。このため、熱膨張部材６１の軸方向への移動は、段部２３ｄと端面３１ｄとによって制限される。また、熱膨張部材６１は、外周面が収容孔２３ｃの内周面に当接するため、径方向外側への移動が収容孔２３ｃの内周面によって制限される。 The thermal expansion member 61 is a member having a C-shaped cross section that is inserted in the axial direction along the accommodation hole 23c. The thermal expansion member 61 is disposed so as to contact the stepped portion 23d and the end surface 31d of the first core 31 in the axial direction. For this reason, the movement of the thermal expansion member 61 in the axial direction is limited by the step portion 23d and the end surface 31d. In addition, since the outer peripheral surface of the thermal expansion member 61 abuts on the inner peripheral surface of the accommodation hole 23c, the outward movement in the radial direction is limited by the inner peripheral surface of the accommodation hole 23c.
　このように、熱膨張部材６１は、軸方向及び径方向外側への移動が制限されるため、磁気粘性流体の温度が高くなると移動が制限されていない径方向内側及び周方向へと膨張する。熱膨張部材６１がバイパス流路２３に直交する方向である径方向内側及び周方向へと膨張することで、第２貫通孔２３ｂの流路面積が減少し、バイパス流路２３の流通抵抗が上昇する。 Thus, since the movement of the thermal expansion member 61 is restricted in the axial direction and radially outward, the thermal expansion member 61 expands radially inward and circumferentially where movement is not restricted when the temperature of the magnetorheological fluid increases. When the thermal expansion member 61 expands radially inward and circumferentially, which is a direction orthogonal to the bypass flow path 23, the flow area of the second through hole 23b is reduced, and the flow resistance of the bypass flow path 23 is increased. To do.
　一方、磁気粘性流体の温度が低くなると熱膨張部材６１は収縮し、第２貫通孔２３ｂの流路面積が増加する。この結果、バイパス流路２３の流通抵抗が低下する。熱膨張部材６１が収縮した際に第２貫通孔２３ｂの流路面積が速やかに拡大されるように、保護部材６２を、熱膨張部材６１を径方向外側へと押圧する力を有する弾性体として形成してもよい。 On the other hand, when the temperature of the magnetorheological fluid decreases, the thermal expansion member 61 contracts and the flow path area of the second through hole 23b increases. As a result, the flow resistance of the bypass flow path 23 decreases. When the thermal expansion member 61 contracts, the protective member 62 is an elastic body having a force that presses the thermal expansion member 61 radially outward so that the flow passage area of the second through hole 23b is quickly expanded. It may be formed.
　保護部材６２は、図３に示されるように、熱膨張部材６１の内周面に沿って設けられる断面Ｃ字状の本体部６２ａと、本体部６２ａの開口端から径方向外側へ延びる端部６２ｂと、を有する。端部６２ｂの径方向の長さは、熱膨張部材６１が最も膨張したときであっても、端部６２ｂの外径側端が第２貫通孔２３ｂよりも径方向外側に位置するように、かつ、熱膨張部材６１が最も収縮したときであっても、端部６２ｂの外径側端が収容孔２３ｃの内周面に当接しないように設定される。このように設定される保護部材６２によって熱膨張部材６１を覆うことにより、主に磁気粘性流体が流通する流路に対して熱膨張部材６１が露出されることが防止され、結果として、磁気粘性流体に含まれる粒子等によって熱膨張部材６１が摩耗することを抑制することができる。 As shown in FIG. 3, the protection member 62 has a C-shaped main body 62a provided along the inner peripheral surface of the thermal expansion member 61, and an end extending radially outward from the opening end of the main body 62a. 62b. The radial length of the end portion 62b is such that the outer diameter side end of the end portion 62b is located radially outside the second through-hole 23b even when the thermal expansion member 61 is most expanded. In addition, even when the thermal expansion member 61 is most contracted, the outer diameter side end of the end portion 62b is set so as not to contact the inner peripheral surface of the accommodation hole 23c. Covering the thermal expansion member 61 with the protective member 62 set in this way prevents the thermal expansion member 61 from being exposed to the flow path through which the magnetic viscous fluid mainly circulates. As a result, the magnetic viscosity It is possible to suppress the thermal expansion member 61 from being worn by particles contained in the fluid.
　続いて、温度補償部６０の組み付け方法について説明する。 Subsequently, a method of assembling the temperature compensation unit 60 will be described.
　ピストン２０への温度補償部６０の組み付けは、ピストンコア３０を組み立てる前に行われる。具体的には、温度補償部６０は、第２コア３２に形成された収容孔２３ｃ内に、その一端が段部２３ｄに当接するまで挿入される。そして、温度補償部６０が挿入された第２コア３２の端面３２ｅを、第１コア３１の端面３１ｄに押し当て、第１コア３１と第２コア３２との間にコイルアセンブリ３３を挟み込むことによりピストンコア３０が組み立てられる。このとき、温度補償部６０は、段部２３ｄと端面３１ｄとにより軸方向への移動が規制され、収容孔２３ｃ内に組み付けられた状態となる。 The assembly of the temperature compensation unit 60 to the piston 20 is performed before the piston core 30 is assembled. Specifically, the temperature compensation unit 60 is inserted into the accommodation hole 23c formed in the second core 32 until one end thereof comes into contact with the stepped portion 23d. Then, the end face 32e of the second core 32 into which the temperature compensation unit 60 is inserted is pressed against the end face 31d of the first core 31, and the coil assembly 33 is sandwiched between the first core 31 and the second core 32. The piston core 30 is assembled. At this time, the temperature compensation unit 60 is restricted from moving in the axial direction by the step portion 23d and the end surface 31d, and is assembled in the accommodation hole 23c.
　このように、温度補償部６０は、収容孔２３ｃ内への挿入という極めて単純な方法によってピストン２０へ組み付けられる。 Thus, the temperature compensation unit 60 is assembled to the piston 20 by a very simple method of insertion into the accommodation hole 23c.
　温度補償部６０が挿入される位置、すなわち、収容孔２３ｃが形成される位置は、第２コア３２に限定されず、バイパス流路２３が形成される第１コア３１であってもよい。また、収容孔２３ｃは、複数の部材に跨って形成されてもよい。 The position where the temperature compensation unit 60 is inserted, that is, the position where the accommodation hole 23c is formed is not limited to the second core 32, but may be the first core 31 where the bypass flow path 23 is formed. The accommodation hole 23c may be formed across a plurality of members.
　次に、緩衝器１００の作用について説明する。 Next, the operation of the shock absorber 100 will be described.
　緩衝器１００が伸縮作動して、ピストンロッド２１がシリンダ１０に対して進退すると、磁気粘性流体は、プレート４０に形成された流路２４とバイパス分岐路２５とを通じてメイン流路２２とバイパス流路２３とを流れる。これにより、磁気粘性流体が流体室１１と流体室１２との間を流通することで、ピストン２０はシリンダ１０内を摺動する。 When the shock absorber 100 expands and contracts and the piston rod 21 advances and retreats with respect to the cylinder 10, the magnetorheological fluid passes through the flow path 24 and the bypass branch path 25 formed in the plate 40 and the main flow path 22 and the bypass flow path. 23. Thereby, the piston 20 slides in the cylinder 10 as the magnetorheological fluid flows between the fluid chamber 11 and the fluid chamber 12.
　このとき、磁性材によって形成される第１コア３１と第２コア３２とフラックスリング３５とは、コイル３３ａのまわりに生じる磁束を導く磁路を構成する。また、プレート４０は非磁性材によって形成されるため、ピストンコア３０とフラックスリング３５との間のメイン流路２２は、コイル３３ａのまわりに生じる磁束が通過する磁気ギャップとなる。これにより、緩衝器１００の伸縮作動時に、メイン流路２２を流れる磁気粘性流体にはコイル３３ａの磁場が作用する。 At this time, the first core 31, the second core 32, and the flux ring 35 formed of a magnetic material constitute a magnetic path that guides a magnetic flux generated around the coil 33a. Further, since the plate 40 is formed of a nonmagnetic material, the main flow path 22 between the piston core 30 and the flux ring 35 becomes a magnetic gap through which the magnetic flux generated around the coil 33a passes. Thereby, the magnetic field of the coil 33a acts on the magnetorheological fluid flowing through the main flow path 22 during the expansion / contraction operation of the shock absorber 100.
　緩衝器１００が発生する減衰力の調節は、コイル３３ａへの通電量を変化させ、メイン流路２２を流れる磁気粘性流体に作用する磁場の強さを変化させることによって行われる。具体的には、コイル３３ａに供給される電流が大きくなるほど、コイル３３ａのまわりに発生する磁場の強さが大きくなる。よって、メイン流路２２を流れる磁気粘性流体の粘性が高くなって、緩衝器１００が発生する減衰力が大きくなる。 The adjustment of the damping force generated by the shock absorber 100 is performed by changing the amount of current supplied to the coil 33a and changing the strength of the magnetic field acting on the magnetorheological fluid flowing through the main flow path 22. Specifically, as the current supplied to the coil 33a increases, the strength of the magnetic field generated around the coil 33a increases. Therefore, the viscosity of the magnetorheological fluid flowing through the main flow path 22 increases, and the damping force generated by the shock absorber 100 increases.
　減衰力を大きくするために、コイル３３ａへの通電量を急激に変化させると磁気粘性流体の粘性が急激に高くなり圧力変動が生じることがある。緩衝器１００において、バイパス流路２３は、コイル３３ａの磁場の影響を受けにくい場所に設けられている。このため、コイル３３ａへの通電量を変化させてもバイパス流路２３を流れる磁気粘性流体の粘性はあまり変化しない。この結果、コイル３３ａへの通電量を変化させることによって減衰力を変化させる際に生じる圧力変動は、バイパス流路２３が設けられることによって緩和される。 If the amount of current supplied to the coil 33a is suddenly changed in order to increase the damping force, the viscosity of the magnetorheological fluid may rapidly increase and pressure fluctuation may occur. In the shock absorber 100, the bypass flow path 23 is provided in a place that is not easily affected by the magnetic field of the coil 33a. For this reason, even if the energization amount to the coil 33a is changed, the viscosity of the magnetorheological fluid flowing through the bypass passage 23 does not change so much. As a result, the pressure fluctuation that occurs when the damping force is changed by changing the amount of current supplied to the coil 33a is alleviated by providing the bypass flow path 23.
　また、緩衝器１００の伸縮作動に伴い磁気粘性流体の温度が上昇すると、磁気粘性流体の粘度が低下するため、メイン流路２２にて発生する減衰力が低下してしまう。緩衝器１００では、磁気粘性流体の温度が上昇すると、温度補償部６０が膨張し、第２貫通孔２３ｂの流路面積を減少させ、バイパス流路２３の流通抵抗を増大させる。つまり、温度補償部６０は、磁気粘性流体の温度が高いときには、減衰力の低下を抑制するように作用する。 Further, when the temperature of the magnetorheological fluid rises due to the expansion / contraction operation of the shock absorber 100, the viscosity of the magnetorheological fluid decreases, so that the damping force generated in the main flow path 22 decreases. In the shock absorber 100, when the temperature of the magnetorheological fluid rises, the temperature compensation unit 60 expands, the flow area of the second through hole 23b is decreased, and the flow resistance of the bypass flow path 23 is increased. That is, the temperature compensation unit 60 acts to suppress a decrease in damping force when the temperature of the magnetorheological fluid is high.
　一方、磁気粘性流体の温度が低いときには、磁気粘性流体の粘度が高いため、メイン流路２２にて発生する減衰力が上昇してしまう。緩衝器１００では、磁気粘性流体の温度が低いときには、温度補償部６０が収縮し、第２貫通孔２３ｂの流路面積を大きくし、バイパス流路２３の流通抵抗を小さくする。つまり、温度補償部６０は、磁気粘性流体の温度が低いときには、減衰力の上昇を抑制するように作用する。 On the other hand, when the temperature of the magnetorheological fluid is low, since the viscosity of the magnetorheological fluid is high, the damping force generated in the main flow path 22 is increased. In the shock absorber 100, when the temperature of the magnetorheological fluid is low, the temperature compensation unit 60 contracts, increasing the flow path area of the second through hole 23b and decreasing the flow resistance of the bypass flow path 23. That is, the temperature compensation unit 60 acts to suppress an increase in damping force when the temperature of the magnetorheological fluid is low.
　ここで、バイパス流路２３がメイン流路２２と同様にコイル３３ａが発生する磁場の影響を受けると、バイパス流路２３を流通する磁気粘性流体の粘度は磁力と温度との両方に起因して変化する。このため、例えば、磁気粘性流体の温度が高くなりバイパス流路２３の流通抵抗を大きくしたときに、磁場の影響で粘度が高くなると、磁気粘性流体の温度が高くなったことにより低下した減衰力を補償するために必要な減衰力よりも大きな減衰力がバイパス流路２３で発生するおそれがある。 Here, when the bypass channel 23 is affected by the magnetic field generated by the coil 33a as in the main channel 22, the viscosity of the magnetorheological fluid flowing through the bypass channel 23 is caused by both the magnetic force and the temperature. Change. For this reason, for example, when the viscosity of the magnetic viscous fluid increases when the temperature of the magnetic viscous fluid increases and the flow resistance of the bypass channel 23 increases, the damping force decreases due to the increased temperature of the magnetic viscous fluid. There is a possibility that a damping force larger than the damping force necessary to compensate for the above will be generated in the bypass channel 23.
　そこで、本実施形態では、温度補償部６０が挿入されるバイパス流路２３は、メイン流路２２と比較してコイル３３ａが発生する磁場の影響が小さい位置に設けられる。このため、バイパス流路２３を流通する磁気粘性流体の粘度はほぼ温度のみによって変化する。つまり、バイパス流路２３では、温度のみに起因して粘度が変化する磁気粘性流体に対して流通抵抗が増減される。この結果、温度変化による粘性変化に起因する減衰力の変化を補償するために必要なだけの減衰力をバイパス流路２３で発生させることができる。 Therefore, in the present embodiment, the bypass flow path 23 in which the temperature compensation unit 60 is inserted is provided at a position where the influence of the magnetic field generated by the coil 33a is smaller than that of the main flow path 22. For this reason, the viscosity of the magnetorheological fluid flowing through the bypass flow path 23 changes substantially only by temperature. That is, in the bypass channel 23, the flow resistance is increased or decreased with respect to the magnetorheological fluid whose viscosity changes due to temperature alone. As a result, it is possible to generate a sufficient damping force in the bypass flow path 23 to compensate for a change in the damping force due to a viscosity change due to a temperature change.
　このように、温度補償部６０が設けられることによって、温度変化による磁気粘性流体の粘性変化に起因する緩衝器１００の減衰力の変化は補償される。この結果、磁気粘性流体の温度変化に関わらず、コイル３３ａへの通電量を調整することによって、所望の減衰力を発生させることができる。 Thus, by providing the temperature compensation unit 60, the change in the damping force of the shock absorber 100 due to the viscosity change of the magnetorheological fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
　以上の実施形態によれば、以下に示す効果を奏する。 According to the above embodiment, the following effects are obtained.
　緩衝器１００では、磁気粘性流体の温度に応じて変形する温度補償部６０は、ピストンコア３０に貫通して形成されるバイパス流路２３に挿入される。このように、温度補償部６０が挿入されるバイパス流路２３は、単なる貫通孔であるため容易に形成することが可能である。この結果、緩衝器１００の製造コストの上昇を抑制することができる。 In the shock absorber 100, the temperature compensation unit 60 that is deformed according to the temperature of the magnetorheological fluid is inserted into the bypass passage 23 formed through the piston core 30. Thus, since the bypass flow path 23 into which the temperature compensation unit 60 is inserted is a simple through hole, it can be easily formed. As a result, an increase in manufacturing cost of the shock absorber 100 can be suppressed.
　さらに、バイパス流路２３に挿入される温度補償部６０は、磁気粘性流体の温度に応じてバイパス流路２３に直交する方向に変形し、バイパス流路２３の流通抵抗を変化させる。このため、温度変化による磁気粘性流体の粘性変化に起因する緩衝器１００の減衰力の変化は補償される。この結果、磁気粘性流体の温度変化に関わらず、コイル３３ａへの通電量を調整することによって、所望の減衰力を発生させることができる。 Furthermore, the temperature compensation unit 60 inserted into the bypass channel 23 is deformed in a direction perpendicular to the bypass channel 23 according to the temperature of the magnetorheological fluid, and changes the flow resistance of the bypass channel 23. For this reason, the change of the damping force of the shock absorber 100 due to the viscosity change of the magnetorheological fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
　次に、図４を参照して、本発明の実施形態に係る緩衝器１００の変形例について説明する。図４は、上記実施形態の図３に相当する断面図である。 Next, a modified example of the shock absorber 100 according to the embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view corresponding to FIG. 3 of the above embodiment.
　上記実施形態では、収容孔２３ｃの断面形状は円形である。これに代えて、図４に示すように、温度補償部２６０が収容される収容孔２２３ｃの断面形状を矩形としてもよい。 In the above embodiment, the cross-sectional shape of the accommodation hole 23c is circular. Instead, as shown in FIG. 4, the cross-sectional shape of the accommodation hole 223c in which the temperature compensation unit 260 is accommodated may be rectangular.
　変形例では、第２貫通孔２３ｂの一部に形成される収容孔２２３ｃの断面形状が、他の部分の直径よりも長さが長い長辺を有する矩形に形成される。収容孔２２３ｃには、断面形状が矩形の温度補償部２６０が対向して２つ配置される。第２貫通孔２３ｂにおける流路面積は、２つの温度補償部２６０と収容孔２２３ｃとにより画定される流路の大きさによって決定され、この流路面積は、温度補償部２６０が変形した場合であっても、第１貫通孔２３ａの流路面積よりも小さくなるように設定される。したがって、上記実施形態と同様に、ピストン２０が移動する時の減衰特性は、第２貫通孔２３ｂの流路面積によって決定され、第１貫通孔２３ａの穴径は、減衰特性に影響を及ぼさない。 In a modification, the cross-sectional shape of the accommodation hole 223c formed in a part of the second through hole 23b is formed in a rectangle having a long side whose length is longer than the diameter of the other part. Two temperature compensation portions 260 having a rectangular cross-sectional shape are disposed in the housing hole 223c so as to face each other. The flow passage area in the second through hole 23b is determined by the size of the flow passage defined by the two temperature compensation portions 260 and the accommodation hole 223c. This flow passage area is obtained when the temperature compensation portion 260 is deformed. Even if it exists, it sets so that it may become smaller than the flow-path area of the 1st through-hole 23a. Therefore, as in the above embodiment, the damping characteristic when the piston 20 moves is determined by the flow passage area of the second through hole 23b, and the hole diameter of the first through hole 23a does not affect the damping characteristic. .
　温度補償部２６０は、熱膨張率が大きい熱膨張部材２６１と、熱膨張部材２６１の表面を覆う保護部材２６２と、を有する。熱膨張部材２６１及び保護部材２６２は、上記実施形態における熱膨張部材６１及び保護部材６２と同様の材料によって形成される。 The temperature compensation unit 260 includes a thermal expansion member 261 having a large coefficient of thermal expansion, and a protection member 262 that covers the surface of the thermal expansion member 261. The thermal expansion member 261 and the protection member 262 are formed of the same material as the thermal expansion member 61 and the protection member 62 in the above embodiment.
　熱膨張部材２６１は、上記実施形態の熱膨張部材６１と同様に、軸方向において段部２２３ｄと第１コア３１の端面３１ｄとに当接するように収容孔２２３ｃ内に配置される。このため、熱膨張部材２６１の軸方向への移動は、段部２２３ｄと端面３１ｄとによって制限される。さらに、熱膨張部材２６１は、断面形状が矩形の収容孔２２３ｃ内に配置されるため、熱膨張部材２６１の移動は、収容孔２２３ｃに直交する方向へのみ許容される。 The thermal expansion member 261 is disposed in the accommodation hole 223c so as to contact the stepped portion 223d and the end surface 31d of the first core 31 in the axial direction, similarly to the thermal expansion member 61 of the above embodiment. For this reason, the movement of the thermal expansion member 261 in the axial direction is limited by the step portion 223d and the end surface 31d. Further, since the thermal expansion member 261 is disposed in the accommodation hole 223c having a rectangular cross-sectional shape, the movement of the thermal expansion member 261 is allowed only in the direction orthogonal to the accommodation hole 223c.
　このため、熱膨張部材２６１は、磁気粘性流体の温度が高くなると移動が制限されていない収容孔２２３ｃに直交する方向へと膨張する。熱膨張部材２６１が膨張することで、第２貫通孔２３ｂの流路面積が減少し、バイパス流路２３の流通抵抗が上昇する。 For this reason, the thermal expansion member 261 expands in a direction orthogonal to the accommodation hole 223c where movement is not restricted when the temperature of the magnetorheological fluid increases. As the thermal expansion member 261 expands, the flow passage area of the second through hole 23b decreases, and the flow resistance of the bypass flow passage 23 increases.
　一方、磁気粘性流体の温度が低くなると熱膨張部材２６１は収縮し、第２貫通孔２３ｂの流路面積が増加する。この結果、バイパス流路２３の流通抵抗が低下する。 On the other hand, when the temperature of the magnetorheological fluid decreases, the thermal expansion member 261 contracts, and the flow path area of the second through hole 23b increases. As a result, the flow resistance of the bypass flow path 23 decreases.
　熱膨張部材２６１が収縮した際に第２貫通孔２３ｂの流路面積が速やかに拡大されるように、２つの温度補償部２６０の間には、熱膨張部材２６１同士を離間させる方向に押圧する付勢力を発揮する弾性体２６３が設けられる。弾性体２６３は、温度補償部２６０が収容孔２２３ｃから脱落したり、収容孔２２３ｃ内において傾いたりすることを防止する機能も有する。 When the thermal expansion member 261 contracts, the thermal expansion member 261 is pressed in the direction of separating the two thermal compensation members 260 so that the flow passage area of the second through hole 23b is quickly expanded. An elastic body 263 that exerts an urging force is provided. The elastic body 263 also has a function of preventing the temperature compensation unit 260 from dropping from the accommodation hole 223c or tilting in the accommodation hole 223c.
　温度補償部２６０の数は、２つに限定されず、１つであってもよい。この場合も温度補償部２６０が収縮した際に第２貫通孔２３ｂの流路面積が速やかに拡大されるように弾性体２６３を設けることが好ましい。 The number of temperature compensation units 260 is not limited to two, and may be one. Also in this case, it is preferable to provide the elastic body 263 so that the flow passage area of the second through hole 23b is quickly expanded when the temperature compensation unit 260 contracts.
　収容孔２２３ｃの断面形状は、矩形に限定されず、長手方向の長さが第１貫通孔２３ａ及び第２貫通孔２３ｂの直径よりも長く、第２貫通孔２３ｂと収容孔２２３ｃとの間に段部２２３ｄが形成されれば、楕円や角丸長方形であってもよい。 The cross-sectional shape of the accommodation hole 223c is not limited to a rectangle, and the length in the longitudinal direction is longer than the diameters of the first through hole 23a and the second through hole 23b, and between the second through hole 23b and the accommodation hole 223c. If the step 223d is formed, it may be an ellipse or a rounded rectangle.
　以上の変形例によっても上記実施形態と同様に、磁気粘性流体の温度に応じて変形する温度補償部２６０は、ピストンコア３０に貫通して形成されるバイパス流路２３に挿入される。このように、温度補償部２６０が挿入されるバイパス流路２３は、貫通孔であるため容易に形成することが可能である。この結果、緩衝器１００の製造コストの上昇を抑制することができる。 As in the above-described embodiment, the temperature compensation unit 260 that deforms according to the temperature of the magnetorheological fluid is inserted into the bypass channel 23 that is formed through the piston core 30 in the above modification. Thus, the bypass flow path 23 into which the temperature compensation unit 260 is inserted is a through hole and can be easily formed. As a result, an increase in manufacturing cost of the shock absorber 100 can be suppressed.
　さらに、バイパス流路２３に挿入される温度補償部２６０は、磁気粘性流体の温度に応じてバイパス流路２３に直交する方向に変形し、バイパス流路２３の流通抵抗を変化させる。このため、温度変化による磁気粘性流体の粘性変化に起因する緩衝器１００の減衰力の変化は補償される。この結果、磁気粘性流体の温度変化に関わらず、コイル３３ａへの通電量を調整することによって、所望の減衰力を発生させることができる。 Furthermore, the temperature compensation unit 260 inserted into the bypass channel 23 is deformed in a direction orthogonal to the bypass channel 23 according to the temperature of the magnetorheological fluid, and changes the flow resistance of the bypass channel 23. For this reason, the change of the damping force of the shock absorber 100 due to the viscosity change of the magnetorheological fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
　以下、本発明の実施形態の構成、作用、及び効果をまとめて説明する。 Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.
　緩衝器１００は、作動流体が封入されるシリンダ１０と、シリンダ１０内に摺動自在に配置され、シリンダ１０内に一対の流体室１１，１２を画成するピストン２０と、ピストン２０に連結されてシリンダ１０の外部へ延在するピストンロッド２１と、を備え、ピストン２０は、一対の流体室１１，１２を連通し、ピストン２０の移動によって作動流体が流通するとともに、流通する作動流体に抵抗を付与するメイン流路２２と、メイン流路２２と並列に設けられ、一対の流体室１１，１２を連通するバイパス流路２３と、バイパス流路２３に挿入され、作動流体の温度に応じてバイパス流路２３に直交する方向に変形することによってバイパス流路２３の流路面積を変化させる温度補償部６０，２６０と、を有する。 The shock absorber 100 is connected to the cylinder 10 in which the working fluid is sealed, the piston 20 that is slidably disposed in the cylinder 10, and that defines a pair of fluid chambers 11 and 12 in the cylinder 10, and the piston 20. A piston rod 21 extending to the outside of the cylinder 10, and the piston 20 communicates with the pair of fluid chambers 11 and 12, and the working fluid circulates by the movement of the piston 20 and resists the circulated working fluid. Is provided in parallel with the main flow path 22, and is connected to the bypass flow path 23 that communicates the pair of fluid chambers 11, 12, and is inserted into the bypass flow path 23 according to the temperature of the working fluid. Temperature compensation units 60 and 260 that change the flow channel area of the bypass flow channel 23 by being deformed in a direction orthogonal to the bypass flow channel 23.
　この構成では、作動流体の温度に応じて変形する温度補償部６０，２６０は、ピストンコア３０に貫通して形成されるバイパス流路２３に挿入される。このように、温度補償部６０，２６０が挿入されるバイパス流路２３は、単なる貫通孔であるため容易に形成することが可能である。この結果、緩衝器１００の製造コストの上昇を抑制することができる。 In this configuration, the temperature compensation units 60 and 260 that are deformed according to the temperature of the working fluid are inserted into the bypass channel 23 that is formed through the piston core 30. Thus, since the bypass flow path 23 into which the temperature compensation parts 60 and 260 are inserted is a simple through hole, it can be easily formed. As a result, an increase in manufacturing cost of the shock absorber 100 can be suppressed.
　さらに、バイパス流路２３に挿入される温度補償部６０，２６０は、作動流体の温度に応じてバイパス流路２３に直交する方向に変形し、バイパス流路２３の流通抵抗を変化させる。このため、温度変化による作動流体の粘性変化に起因する緩衝器１００の減衰力の変化は補償される。この結果、作動流体の温度変化に関わらず、コイル３３ａへの通電量を調整することによって、所望の減衰力を発生させることができる。 Furthermore, the temperature compensation units 60 and 260 inserted into the bypass channel 23 are deformed in a direction orthogonal to the bypass channel 23 according to the temperature of the working fluid, and change the flow resistance of the bypass channel 23. For this reason, the change in the damping force of the shock absorber 100 due to the change in the viscosity of the working fluid due to the temperature change is compensated. As a result, a desired damping force can be generated by adjusting the energization amount to the coil 33a regardless of the temperature change of the working fluid.
　また、温度補償部６０，２６０は、樹脂製の熱膨張部材６１，２６１と、熱膨張部材６１，２６１の少なくとも一部の表面を覆う金属製の保護部材６２，２６２と、を有する。 The temperature compensation units 60 and 260 include resin thermal expansion members 61 and 261 and metal protection members 62 and 262 that cover at least a part of the surface of the thermal expansion members 61 and 261.
　この構成では、熱膨張部材６１，２６１の表面を覆う保護部材６２，２６２が配置され、樹脂製の熱膨張部材６１，２６１が作動流体に直接接触することが防止される。このため、樹脂製の熱膨張部材６１，２６１が作動流体により摩耗することを抑制することができる。 In this configuration, the protective members 62 and 262 that cover the surfaces of the thermal expansion members 61 and 261 are disposed, and the resin thermal expansion members 61 and 261 are prevented from coming into direct contact with the working fluid. For this reason, it can suppress that the resin-made thermal expansion members 61 and 261 are worn by the working fluid.
　また、バイパス流路２３は、断面円形状の孔であり、熱膨張部材６１は、断面Ｃ字状に形成され、外周面がバイパス流路２３の内周面に当接するように設けられ、保護部材６２は、少なくとも熱膨張部材６１の内周面の一部を覆うように設けられる。 The bypass flow path 23 is a hole having a circular cross section, and the thermal expansion member 61 is formed in a C-shaped cross section, and is provided so that the outer peripheral surface is in contact with the inner peripheral surface of the bypass flow path 23. The member 62 is provided so as to cover at least a part of the inner peripheral surface of the thermal expansion member 61.
　この構成では、バイパス流路２３に挿入される熱膨張部材６１は、断面Ｃ字状に形成される。このため、熱膨張部材６１は、作動流体の温度が高くなると移動が制限されていない径方向内側へと膨張する。この結果、バイパス流路２３の流路面積は作動流体の温度に応じて変化することになるため、バイパス流路２３の流通抵抗を作動流体の温度に応じて変化させることができる。さらに、作動流体が流通する熱膨張部材６１の内周面側には、保護部材６２が設けられる。このため、樹脂製の熱膨張部材６１が作動流体に直接接触することが防止され、熱膨張部材６１が作動流体により摩耗することを抑制することができる。 In this configuration, the thermal expansion member 61 inserted into the bypass channel 23 is formed in a C-shaped cross section. For this reason, when the temperature of the working fluid increases, the thermal expansion member 61 expands inward in the radial direction where movement is not limited. As a result, the flow path area of the bypass flow path 23 changes according to the temperature of the working fluid, so that the flow resistance of the bypass flow path 23 can be changed according to the temperature of the working fluid. Further, a protective member 62 is provided on the inner peripheral surface side of the thermal expansion member 61 through which the working fluid flows. For this reason, it is possible to prevent the resin thermal expansion member 61 from coming into direct contact with the working fluid, and to prevent the thermal expansion member 61 from being worn by the working fluid.
　また、作動流体は磁気粘性流体であり、ピストン２０は、ピストンロッド２１の端部に取り付けられ外周にコイル３３ａが設けられるピストンコア３０と、ピストンコア３０の外周を取り囲むフラックスリング３５と、を有し、メイン流路２２は、ピストンコア３０の外周とフラックスリング３５の内周とにより画定され、バイパス流路２３は、メイン流路２２との間にコイル３３ａを挟むようにしてピストンコア３０に形成される。 The working fluid is a magnetorheological fluid, and the piston 20 has a piston core 30 attached to the end of the piston rod 21 and provided with a coil 33a on the outer periphery, and a flux ring 35 surrounding the outer periphery of the piston core 30. The main flow path 22 is defined by the outer periphery of the piston core 30 and the inner periphery of the flux ring 35, and the bypass flow path 23 is formed in the piston core 30 so as to sandwich the coil 33 a between the main flow path 22. The
　この構成では、温度補償部６０，２６０が挿入されるバイパス流路２３は、メイン流路２２と比較してコイル３３ａが発生する磁場の影響が小さい位置に設けられる。このように、温度補償部６０，２６０では、コイル３３ａが発生する磁場の影響を受けることが抑制されるため、温度変化による粘性変化に起因する減衰力の変化を補償することができる。この結果、磁気粘性流体の温度変化に関わらず、コイル３３ａへの通電量を調整することによって、所望の減衰力を発生させることができる。 In this configuration, the bypass flow path 23 in which the temperature compensation units 60 and 260 are inserted is provided at a position where the influence of the magnetic field generated by the coil 33a is smaller than that of the main flow path 22. As described above, since the temperature compensation units 60 and 260 are suppressed from being affected by the magnetic field generated by the coil 33a, it is possible to compensate for a change in damping force due to a viscosity change due to a temperature change. As a result, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a regardless of the temperature change of the magnetorheological fluid.
　以上、本発明の実施形態について説明したが、上記実施形態は本発明の適用例の一部を示したに過ぎず、本発明の技術的範囲を上記実施形態の具体的構成に限定する趣旨ではない。 The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.
　例えば、緩衝器１００は、コイル３３ａに電流を供給する一対の配線がピストンロッド２１の内周を通過するものである。よって、コイル３３ａに印加された電流を外部に逃がすアースを廃止することができる。しかしながら、この構成に代えて、コイル３３ａに電流を印加する一本の配線のみがピストンロッド２１の内部を通過するようにして、ピストンロッド２１自体を通じて外部にアースされる構成としてもよい。 For example, in the shock absorber 100, a pair of wires for supplying a current to the coil 33a passes through the inner periphery of the piston rod 21. Therefore, it is possible to eliminate the ground for allowing the current applied to the coil 33a to escape to the outside. However, instead of this configuration, only one wire for applying a current to the coil 33a may pass through the inside of the piston rod 21 and be grounded to the outside through the piston rod 21 itself.
　また、温度補償部６０，２６０は、磁気粘性流体を用いた緩衝器１００に限定されず、作動油を用いた一般的な緩衝器の絞り流路に適用することも可能である。この場合も流路に作動油の温度に応じて変形する温度補償部を挿入するという簡素な構成によって、温度に応じて流路の断面積を変更することが可能となる。この結果、温度変化による作動油の粘性変化に起因する緩衝器の減衰力の変化を補償することができる。 Further, the temperature compensation units 60 and 260 are not limited to the shock absorber 100 using a magnetorheological fluid, and can be applied to a throttle channel of a general shock absorber using hydraulic oil. In this case as well, the cross-sectional area of the flow path can be changed according to the temperature by a simple configuration in which a temperature compensation unit that deforms according to the temperature of the hydraulic oil is inserted into the flow path. As a result, it is possible to compensate for the change in the damping force of the shock absorber caused by the change in the viscosity of the hydraulic oil due to the temperature change.
　本願は２０１５年９月１６日に日本国特許庁に出願された特願２０１５－１８２８９０に基づく優先権を主張し、この出願の全ての内容は参照により本明細書に組み込まれる。 This application claims priority based on Japanese Patent Application No. 2015-182890 filed with the Japan Patent Office on September 16, 2015, the entire contents of which are incorporated herein by reference.

Claims (4)

  1. 　緩衝器であって、
    　作動流体が封入されるシリンダと、
    　前記シリンダ内に摺動自在に配置され、前記シリンダ内に一対の流体室を画成するピストンと、
    　前記ピストンに連結されて前記シリンダの外部へ延在するピストンロッドと、を備え、
    　前記ピストンは、
    　一対の前記流体室を連通し、前記ピストンの移動によって作動流体が流通するとともに、流通する作動流体に抵抗を付与するメイン流路と、
    　前記メイン流路と並列に設けられ、一対の前記流体室を連通するバイパス流路と、
    　前記バイパス流路に挿入され、作動流体の温度に応じて前記バイパス流路に直交する方向に変形することによって前記バイパス流路の流路面積を変化させる温度補償部と、を有する緩衝器。     A shock absorber,
    A cylinder filled with a working fluid;
    A piston slidably disposed within the cylinder and defining a pair of fluid chambers within the cylinder;
    A piston rod connected to the piston and extending to the outside of the cylinder,
    The piston is
    A main flow path that communicates a pair of the fluid chambers and distributes the working fluid through the movement of the piston and imparts resistance to the circulating working fluid;
    A bypass flow path provided in parallel with the main flow path and communicating the pair of fluid chambers;
    And a temperature compensator that is inserted into the bypass channel and changes a channel area of the bypass channel by being deformed in a direction orthogonal to the bypass channel according to the temperature of the working fluid.
  2. 　請求項１に記載の緩衝器であって、
    　前記温度補償部は、
    　樹脂製の熱膨張部材と、
    　前記熱膨張部材の少なくとも一部の表面を覆う金属製の保護部材と、を有する緩衝器。     The shock absorber according to claim 1,
    The temperature compensation unit is
    A resin thermal expansion member;
    And a metal protective member that covers at least a part of the surface of the thermal expansion member.
  3. 　請求項２に記載の緩衝器であって、
    　前記バイパス流路は、断面円形状の孔であり、
    　前記熱膨張部材は、断面Ｃ字状に形成され、外周面が前記バイパス流路の内周面に当接するように設けられ、
    　前記保護部材は、少なくとも前記熱膨張部材の内周面の一部を覆うように設けられる緩衝器。     The shock absorber according to claim 2,
    The bypass channel is a hole having a circular cross section,
    The thermal expansion member is formed in a C-shaped cross section, and an outer peripheral surface is provided so as to abut on an inner peripheral surface of the bypass flow path.
    The said protection member is a buffer provided so that a part of inner peripheral surface of the said thermal expansion member may be covered at least.
  4. 　請求項１に記載の緩衝器であって、
    　作動流体は磁気粘性流体であり、
    　前記ピストンは、
    　前記ピストンロッドの端部に取り付けられ、外周にコイルが設けられるピストンコアと、
    　前記ピストンコアの外周を取り囲むリング体と、を有し、
    　前記メイン流路は、前記ピストンコアの外周と前記リング体の内周とにより画定され、
    　前記バイパス流路は、前記メイン流路との間に前記コイルを挟むようにして前記ピストンコアに形成される緩衝器。     The shock absorber according to claim 1,
    The working fluid is a magnetorheological fluid
    The piston is
    A piston core attached to the end of the piston rod and provided with a coil on the outer periphery;
    A ring body surrounding the outer periphery of the piston core,
    The main flow path is defined by an outer periphery of the piston core and an inner periphery of the ring body,
    The bypass channel is a shock absorber formed in the piston core so as to sandwich the coil between the main channel and the bypass channel.
PCT/JP2016/075062 2015-09-16 2016-08-26 Damper WO2017047360A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2015-182890 2015-09-16
JP2015182890A JP2017057921A (en) 2015-09-16 2015-09-16 Shock absorber

Publications (1)

Publication Number Publication Date
WO2017047360A1 true WO2017047360A1 (en) 2017-03-23

Family

ID=58289033

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2016/075062 WO2017047360A1 (en) 2015-09-16 2016-08-26 Damper

Country Status (2)

Country Link
JP (1) JP2017057921A (en)
WO (1) WO2017047360A1 (en)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5676743A (en) * 1979-11-22 1981-06-24 Showa Mfg Co Ltd Temperature characteristic compensator for hydraulic shock absorber
JPS5970945U (en) * 1982-11-04 1984-05-14 トヨタ自動車株式会社 Shock absorber
JP2013167313A (en) * 2012-02-16 2013-08-29 Kyb Co Ltd Magnetic viscous fluid damper

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5676743A (en) * 1979-11-22 1981-06-24 Showa Mfg Co Ltd Temperature characteristic compensator for hydraulic shock absorber
JPS5970945U (en) * 1982-11-04 1984-05-14 トヨタ自動車株式会社 Shock absorber
JP2013167313A (en) * 2012-02-16 2013-08-29 Kyb Co Ltd Magnetic viscous fluid damper

Also Published As

Publication number Publication date
JP2017057921A (en) 2017-03-23

Similar Documents

Publication Publication Date Title
KR101643495B1 (en) Magneto-viscous fluid damper
US10619694B2 (en) Shock absorber
WO2014148296A1 (en) Magnetorheological fluid damper
WO2013129161A1 (en) Magnetic viscous damper
KR102095094B1 (en) Vibration damping device
US10352390B2 (en) Damper and method of assembling damper
WO2014148292A1 (en) Magnetorheological fluid damper
WO2013129162A1 (en) Magnetic viscous damper
WO2017043253A1 (en) Magnetorheological fluid buffer
WO2015141575A1 (en) Magneto-rheological fluid damper
WO2017047360A1 (en) Damper
JP6088674B1 (en) Magnetorheological fluid shock absorber
WO2017051669A1 (en) Magneto-viscous fluid damper
WO2017043166A1 (en) Magneto-viscous fluid damper
WO2017056816A1 (en) Magnetic viscous fluid buffer

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 16846231

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 16846231

Country of ref document: EP

Kind code of ref document: A1