WO2017056816A1 - Tampon à fluide visqueux magnétique - Google Patents

Tampon à fluide visqueux magnétique Download PDF

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Publication number
WO2017056816A1
WO2017056816A1 PCT/JP2016/075173 JP2016075173W WO2017056816A1 WO 2017056816 A1 WO2017056816 A1 WO 2017056816A1 JP 2016075173 W JP2016075173 W JP 2016075173W WO 2017056816 A1 WO2017056816 A1 WO 2017056816A1
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WO
WIPO (PCT)
Prior art keywords
piston
magnetorheological fluid
coil
flow path
core
Prior art date
Application number
PCT/JP2016/075173
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English (en)
Japanese (ja)
Inventor
睦 小川
康裕 米原
Original Assignee
Ｋｙｂ株式会社
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Filing date
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Publication of WO2017056816A1 publication Critical patent/WO2017056816A1/fr

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    • 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
    • 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
    • F16F9/34—Special valve constructions; Shape or construction of throttling passages
    • 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 magnetorheological fluid shock absorber using a magnetorheological fluid whose apparent viscosity changes due to the action of a magnetic field.
  • a magnetic viscous fluid shock absorber that changes a damping force by applying a magnetic field to a flow path through which the magnetic viscous fluid passes and changing an apparent viscosity of the magnetic viscous fluid.
  • a magnetorheological fluid shock absorber when a piston assembly including a piston core having a coil wound around the outer periphery and a piston ring disposed on the outer periphery of the piston core slides in the cylinder, the piston core A magnetorheological fluid damper is disclosed in which a magnetorheological fluid passes through a flow path formed between the piston ring and the piston ring.
  • JP 4754456B discloses a magnetorheological fluid shock absorber that reduces a change in damping force caused by a temperature change.
  • This magnetorheological fluid shock absorber includes a temperature compensator provided on the outer peripheral surface of the piston core.
  • the temperature compensator moves forward and backward with respect to the piston ring by expanding and contracting according to the temperature of the magnetorheological fluid, and changes the cross-sectional area of the flow path formed between the piston core and the piston ring. Since the flow resistance of the flow path is changed by changing the cross-sectional area of the flow path, the change in the damping force due to the temperature change is reduced.
  • the coil is preferably provided in the vicinity of the flow path.
  • the piston core requires a portion for providing the temperature compensation portion in addition to the portion for winding the coil. Therefore, the piston core is enlarged in the axial direction, and the shock absorber is enlarged.
  • An object of the present invention is to generate a required damping force regardless of a temperature change of a magnetorheological fluid without increasing the size.
  • a magnetorheological fluid shock absorber includes a cylinder in which a magnetorheological fluid whose apparent viscosity is changed by the action of a magnetic field is sealed, a slidable arrangement in the cylinder, and a pair in the cylinder. And a piston core connected to the piston and extending to the outside of the cylinder, the piston being attached to the end of the piston rod and having a coil provided on the outer periphery thereof, An annular ring body that surrounds the outer periphery of the piston core and forms a flow path through which the magnetorheological fluid that flows back and forth between the pair of fluid chambers flows between the piston core and the inner ring body facing the coil.
  • a temperature compensation unit that is provided on the peripheral surface and that moves forward and backward with respect to the coil by expanding and contracting according to temperature.
  • FIG. 1 is a cross-sectional view of a magnetorheological fluid shock absorber according to a first embodiment of the present invention.
  • FIG. 2 is a left side view of the piston in FIG.
  • FIG. 3 is a sectional view taken along line III-III in FIG.
  • FIG. 4 is an enlarged cross-sectional view of the periphery of the temperature compensation unit, showing a state where the temperature of the magnetorheological fluid is high.
  • FIG. 5 is an enlarged cross-sectional view of the periphery of the temperature compensation unit, showing a state where the temperature of the magnetorheological fluid is low.
  • FIG. 6 is a cross-sectional view showing another form of the temperature compensation unit corresponding to FIG. FIG.
  • FIG. 7 is an enlarged cross-sectional view of a magnetorheological fluid shock absorber according to a second embodiment of the present invention.
  • FIG. 8 is an enlarged cross-sectional view of a magnetorheological fluid shock absorber according to a third embodiment of the present invention, showing a state where the temperature of the magnetorheological fluid is high.
  • the shock absorber 100 is a damper whose damping coefficient can be changed by using a magnetorheological fluid whose apparent viscosity changes due to the action of a magnetic field.
  • 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 is a liquid whose apparent viscosity changes due to the action of a magnetic field.
  • a magnetorheological fluid can be obtained by dispersing fine particles having ferromagnetism in a liquid such as oil.
  • the apparent 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 flow path 22 and a bypass flow path 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.
  • FIG. 2 is a left side view of the piston 20.
  • 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.
  • a female screw 31d is formed on the inner peripheral surface of the first small diameter portion 31a to be engaged with the male screw 21d of the piston rod 21.
  • the first core 31 is fastened to the piston rod 21 by screwing the female screw 31d of the first small diameter portion 31a with the male screw 21d of the piston rod 21.
  • a male screw 31e 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 continuously in the axial direction, and forms a step portion 31f between the second small diameter portion 31a and the first small diameter portion 31a.
  • the step portion 31 f is configured such that the inside of the end surface of the plate 40 abuts and the plate 40 is sandwiched 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.
  • 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 portion 33b provided with a coil 33a therein, a connecting portion 33c extending radially inward from one end of the coil mold portion 33b, and an axial direction from the connecting portion 33c. And a cylindrical portion 33d extending to the center.
  • 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, 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 is formed so that the outer diameter is substantially the same as the inner diameter of the large diameter portion 31c, 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 31d 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 formed of a magnetic material having a high rigidity and a low coefficient of thermal expansion.
  • 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 a flow path 22 through which the magnetorheological fluid flows.
  • a groove 36 extending in the circumferential direction is formed on the inner peripheral surface 35 c of the flux ring 35.
  • a temperature compensation unit 60 is provided in the groove 36. The groove 36 and the temperature compensation unit 60 will be described in detail later.
  • the coil mold part 33 b faces the flow path 22. Therefore, the magnetic field generated by the coil 33a acts on the magnetorheological fluid flowing through the flow path 22. That is, the 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.
  • an electric current is supplied to the coil 33a to form a magnetic field, the apparent viscosity of the magnetorheological fluid flowing through the flow path 22 changes.
  • the apparent 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.
  • bypass channel 23 that penetrates in the axial direction is formed at a position where the influence of the magnetic field generated by the coil 33 a is smaller than that of the channel 22.
  • Two bypass channels 23 are formed at intervals of 180 °.
  • the number of bypass channels 23 is not limited to this, and the bypass channels 23 may not be provided.
  • the bypass flow path 23 includes 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 and the coil assembly 33.
  • the hole diameter of the first through hole 23a is small enough to give sufficient resistance to the magnetorheological fluid.
  • the second through hole 23b is formed to have a larger diameter than the first through hole 23a. Therefore, the damping characteristic when the piston 20 slides is determined by the hole diameter of the first through hole 23a. The hole diameter of the second through hole 23b does not affect the damping characteristics when the piston 20 slides.
  • 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.
  • a plurality of flow paths 24 that are through holes communicating with the flow path 22 are formed.
  • 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 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 an interval (width of the 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 31f 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 31e of the first core 31 on the inner periphery of the base end portion 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 member for connecting the flux ring 35 and the piston core 30 is not disposed on the other end 35 b side of the flux ring 35, the 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 flow path 22 is reduced, and the resistance imparted to the magnetorheological fluid passing through the flow path 22 can be reduced.
  • FIG. 3 is a sectional view taken along line III-III in FIG.
  • members other than the piston 20 are omitted for explanation.
  • the groove 36 is formed in an annular shape along the circumferential direction of the flux ring 35 in a region of the inner peripheral surface 35c of the flux ring 35 that faces the coil 33a.
  • a temperature compensation unit 60 is disposed in the groove 36.
  • the temperature compensation unit 60 includes a thermal expansion member 61 and a protection member 62.
  • the thermal expansion member 61 is formed of a material having a larger coefficient of thermal expansion than the flux ring 35, for example, a resin material such as polyethylene and polyethylene terephthalate, or a metal material such as aluminum.
  • the protection member 62 is formed of a material having wear resistance, for example, a metal material such as stainless steel.
  • the thermal expansion member 61 and the protection member 62 are formed in an annular shape.
  • the thermal expansion member 61 is disposed on the bottom surface 36 a of the groove 36.
  • the protection member 62 sandwiches the thermal expansion member 61 between the bottom surface 36a of the groove 36 and faces the coil 33a.
  • a part of the flow path 22 is formed by the protection member 62 and the coil mold part 33b.
  • the outer peripheral surface of the thermal expansion member 61 is fixed to the bottom surface 36 a of the groove 36 with an adhesive, while both end surfaces are not fixed to both side surfaces 36 b and 36 c of the groove 36. Therefore, the thermal expansion member 61 expands and contracts in the groove 36 in the radial direction as the temperature changes.
  • the outer peripheral surface of the protective member 62 is fixed to the inner peripheral surface of the thermal expansion member 61 by an adhesive, while both end surfaces are not fixed to both side surfaces 36 b and 36 c of the groove 36. Therefore, the protection member 62 moves relative to the flux ring 35 as the thermal expansion member 61 expands and contracts, and moves forward and backward with respect to the coil 33a. As the protective member 62 advances and retreats, the cross-sectional area of the flow path 22 changes, and the flow resistance of the flow path 22 changes.
  • the protective member 62 is provided to prevent the resin thermal expansion member 61 from being in direct contact with the magnetorheological fluid and being worn. If the thermal expansion member 61 is not likely to be worn by the magnetorheological fluid, it is not necessary to provide the protection member 62, and the thermal expansion member 61 may be configured to advance and retract directly with respect to the coil 33a.
  • the volume of the thermal expansion member 61 expands, so that the protection member 62 is pushed out to the flow path 22 along the direction of arrow A shown in FIG.
  • the cross-sectional area of the flow path 22 is reduced, and as a result, the flow resistance increases.
  • the bottom surface 36a of the groove 36 functions as a guide portion that restricts the expansion of the thermal expansion member 61 radially outward.
  • 36b and 36c function as a guide part that restricts the expansion of the thermal expansion member 61 in the axial direction. Therefore, the expansion of the thermal expansion member 61 is allowed only in the direction in which the protection member 62 is pushed out with respect to the coil 33a. As described above, the expansion direction of the thermal expansion member 61 is not dispersed and is regulated in one direction, so that the change in the volume of the thermal expansion member 61 can be efficiently reflected in the change in the cross-sectional area of the flow path 22. .
  • the volume of the thermal expansion member 61 contracts, so that the protection member 62 is pushed back from the flow path 22 toward the flux ring 35 along the direction of arrow B shown in FIG.
  • the cross-sectional area of the flow path 22 increases, and as a result, the flow resistance decreases.
  • the temperature compensation unit 60 is not limited to an annular member.
  • FIG. 6 is a cross-sectional view showing another form of the temperature compensation unit 60 corresponding to FIG. As shown in FIG. 6, the temperature compensation unit 60 may be formed in an arc shape, or a plurality of arc-shaped temperature compensation units 60 may be arranged in the circumferential direction.
  • the groove 36 is preferably formed in an arc shape corresponding to the temperature compensation unit 60.
  • the groove 36 is preferably formed in an arc shape corresponding to the temperature compensation unit 60.
  • end surfaces 36 d and 36 e are formed in the groove 36. Since the end faces 36d and 36e restrict the expansion of the temperature compensation unit 60 in the circumferential direction, the volume change of the temperature compensation unit 60 can be efficiently reflected in the change in the cross-sectional area of the flow path 22.
  • 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 flow path 22 and the bypass flow path 23. And flow. 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 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 magnetic viscous fluid which flows through the flow path 22 at the time of expansion-contraction operation of the shock absorber 100.
  • 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 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 apparent viscosity of the magnetorheological fluid flowing through the 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 apparent viscosity of the magnetorheological fluid flowing through the bypass passage 23 does not change 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 compensator 60 advances toward the coil 33a, reducing the cross-sectional area of the flow path 22 and increasing the flow resistance. That is, the temperature compensation unit 60 suppresses a decrease in damping force when the temperature of the magnetorheological fluid is high.
  • the temperature compensation unit 60 moves backward from the coil 33a, and the cross-sectional area of the flow path 22 is increased to reduce the flow resistance. That is, the temperature compensation unit 60 suppresses an increase in damping force when the temperature of the magnetorheological fluid is low.
  • 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 moves back and forth with respect to the coil 33a in accordance with the temperature of the magnetorheological fluid to change the flow resistance. 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 temperature compensation unit 60 is provided on the inner peripheral surface 35 c of the flux ring 35, it is not necessary to provide the temperature compensation unit 60 in the coil mold part 33 b, and the coil 33 a is close to the flow path 22. Therefore, the magnetic field generated by the coil 33a can be efficiently applied to the magnetorheological fluid in the flow path 22.
  • the piston core 30 since the temperature compensation unit 60 is provided on the inner peripheral surface 35c of the flux ring 35 so as to face the coil 33a, the piston core 30 does not require a portion for providing the temperature compensation unit 60. Therefore, the enlargement of the piston core 30 in the axial direction can be prevented, and the enlargement of the shock absorber 100 can be prevented.
  • FIG. 7 is an enlarged cross-sectional view corresponding to FIG. 4 of the first embodiment.
  • the temperature compensation unit 60 is partially provided in a region defining the flow path 22 in the inner peripheral surface 35c of the flux ring 35 (see FIG. 4).
  • the temperature compensator 60 is entirely provided over a region defining the flow path 22 in the inner peripheral surface 35c of the flux ring 35.
  • the temperature compensation unit 60 provided in the shock absorber 200 will be described in detail.
  • the other end 35b of the flux ring 35 is provided with an annular portion 35d formed to project radially inward from the edge of the inner peripheral surface 35c.
  • the annular portion 35 d is located closer to the fluid chamber 12 than the end surface 32 c of the second core 32.
  • the thermal expansion member 61 of the temperature compensation unit 60 is formed in an annular shape, and is provided on the inner peripheral surface 35c of the flux ring 35 from the annular portion 35d to the plate 40.
  • the protection member 62 of the temperature compensation unit 60 is formed in an annular shape, and is provided on the inner peripheral surface of the thermal expansion member 61 from the annular portion 35 d to the plate 40. Since the annular portion 35d is located closer to the fluid chamber 12 than the end surface 32c, the entire flow path 22 is defined by the outer peripheral surface 30b of the large-diameter portion 30a of the piston core 30 and the inner peripheral surface of the protection member 62. .
  • the annular portion 35d and the plate 40 are made of a material having high rigidity and low coefficient of thermal expansion.
  • the outer peripheral surface of the thermal expansion member 61 is fixed to the inner peripheral surface 35c of the flux ring 35 with an adhesive, while both end surfaces are not fixed to the annular portion 35d and the end surface of the plate 40. Therefore, the thermal expansion member 61 expands and contracts in the radial direction as the temperature changes.
  • the protective member 62 has an outer peripheral surface fixed to the inner peripheral surface of the thermal expansion member 61 with an adhesive, while both end surfaces are not fixed to the annular portion 35 d and the end surface of the plate 40. Therefore, the protection member 62 moves relative to the flux ring 35 as the thermal expansion member 61 expands and contracts, and moves forward and backward with respect to the piston core 30. As the protective member 62 advances and retreats, the cross-sectional area of the flow path 22 changes uniformly, and the flow resistance of the flow path 22 changes.
  • the protective member 62 is provided in order to prevent the resin thermal expansion member 61 from being worn by the magnetorheological fluid, as in the first embodiment. If the thermal expansion member 61 is not likely to be worn by the magnetorheological fluid, the protection member 62 need not be provided.
  • the annular portion 35d and the plate 40 are formed of a material having high rigidity and a low coefficient of thermal expansion, they function as a guide portion that restricts the expansion of the thermal expansion member 61 in the axial direction. Therefore, expansion of the thermal expansion member 61 is allowed only in the direction in which the protection member 62 is pushed out with respect to the piston core 30. As described above, the expansion direction of the thermal expansion member 61 is not dispersed and is regulated in one direction, so that the change in the volume of the thermal expansion member 61 can be efficiently reflected in the change in the cross-sectional area of the flow path 22. .
  • 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, as in the first embodiment.
  • the cross-sectional area of the flow path 22 formed between the temperature compensation part 60 and the piston core 30 changes uniformly by advancing and retracting the temperature compensation part 60 with respect to the piston core 30. . Therefore, it is difficult to form a step portion in the flow path 22. Therefore, when designing the flow path 22, it is not necessary to consider the flow resistance due to the stepped portion, and the magnetorheological fluid shock absorber 200 can be designed more easily.
  • FIG. 8 is an enlarged cross-sectional view corresponding to FIG. 4 of the first embodiment, showing a state where the temperature of the magnetorheological fluid is high.
  • a plurality of annular grooves 36 are formed in the axial direction in a region defining the flow path 22 in the inner peripheral surface 35 c of the flux ring 35.
  • One of the plurality of grooves 36 faces the coil 33a.
  • a temperature compensation unit 60 is disposed in each groove 36. As in the first embodiment, each temperature compensation unit 60 is not fixed to both side surfaces 36b and 36c of the groove 36 at both end surfaces. Therefore, the temperature compensation unit 60 moves forward and backward with respect to the piston core 30 as the temperature changes. As a result, the cross-sectional area of the flow path 22 changes, and the flow resistance of the flow path 22 changes.
  • the temperature compensation unit 60 is partially provided on the inner peripheral surface 35 c of the flux ring 35, when the temperature compensation unit 60 advances into the flow channel 22, a plurality of step portions 22 a are formed in the flow channel 22. Since the flow resistance increases in the step portion 22a of the flow path 22, the flow resistance of the flow path 22 can be sufficiently changed even if the flow path 22 is shortened. As a result, the shock absorber 300 can be reduced in size.
  • a desired damping force can be generated by adjusting the energization amount to the coil 33a regardless of the temperature change of the magnetorheological fluid.
  • the step portion 22 a is formed in the flow path 22 by the temperature compensation portion 60 moving forward and backward with respect to the piston core 30. Therefore, even if the flow path 22 is shortened, the flow resistance of the flow path 22 can be sufficiently changed, and the shock absorber 300 can be reduced in size.
  • the shock absorbers 100, 200, and 300 are disposed in a cylinder 10 in which a magnetorheological fluid whose apparent viscosity is changed by the action of a magnetic field is sealed, and are slidably disposed in the cylinder 10. , 12 and a piston rod 21 connected to the piston 20 and extending to the outside of the cylinder 10, and the piston 20 is attached to one end 21a of the piston rod 21 and has a coil 33a on the outer periphery.
  • a temperature compensating unit 60 to advance and retreat with respect to the coil 33a, the Te.
  • the temperature compensation unit 60 moves back and forth with respect to the coil 33a in accordance with the temperature of the magnetorheological fluid, and changes the flow resistance. 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. Further, since the temperature compensation unit 60 is provided on the inner peripheral surface 35c of the flux ring 35 so as to face the coil 33a, the piston core 30 does not require a portion for providing the temperature compensation unit 60. Therefore, a desired damping force can be generated by adjusting the amount of current supplied to the coil 33a without increasing the size.
  • the temperature compensation unit 60 is provided over a region defining the flow path 22 in the inner peripheral surface 35 c of the flux ring 35.
  • the temperature compensation unit 60 moves back and forth with respect to the piston core 30 to change the cross-sectional area of the flow path 22 uniformly.
  • the cross-sectional area of the flow path 22 changes uniformly, it is difficult to form a step in the flow path 22. Therefore, when designing the flow path 22, it is not necessary to consider the flow resistance caused by the stepped portion, and the shock absorber 200 can be designed more easily.
  • the temperature compensation unit 60 is partially provided in a region defining the flow path 22 in the inner peripheral surface 35 c of the flux ring 35.
  • the temperature compensation unit 60 moves forward and backward with respect to the piston core 30 to form the stepped portion 22a in the flow path 22.
  • the step part 22a is formed in the flow path 22, even if the flow path 22 is shortened, the flow resistance of the flow path 22 can be changed sufficiently, and the magnetorheological fluid can be reduced in size. .
  • 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.

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

Abstract

L'invention concerne un tampon (100) comportant un cylindre (10), un piston (20) disposé de manière coulissante à l'intérieur du cylindre (10) et une tige (21) de piston reliée au piston (20). Le piston (20) comporte un noyau (30) de piston muni d'une couronne (33a) sur sa périphérie, un anneau d'écoulement (35) entourant la périphérie du noyau (30) du piston et formant un canal d'écoulement (22) entre le noyau (30) du piston et l'anneau, et une unité de compensation de température (60) qui avance et recule par rapport à la couronne (33a) à cause de la dilatation et de la contraction en fonction de la température et munie, en regard de la couronne (33a), sur une surface circonférentielle interne (35c) de l'anneau d'écoulement (35).
PCT/JP2016/075173 2015-09-29 2016-08-29 Tampon à fluide visqueux magnétique WO2017056816A1 (fr)

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JP2015191620A JP2017067128A (ja) 2015-09-29 2015-09-29 磁気粘性流体緩衝器
JP2015-191620 2015-09-29

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WO2017056816A1 true WO2017056816A1 (fr) 2017-04-06

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5635832A (en) * 1979-08-27 1981-04-08 Kayaba Ind Co Ltd Hydraulic shock absorber
JP2014181808A (ja) * 2013-03-21 2014-09-29 Kayaba Ind Co Ltd 磁気粘性流体緩衝器

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5635832A (en) * 1979-08-27 1981-04-08 Kayaba Ind Co Ltd Hydraulic shock absorber
JP2014181808A (ja) * 2013-03-21 2014-09-29 Kayaba Ind Co Ltd 磁気粘性流体緩衝器

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