JP2016017535A - Suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve conversion efficiency between rotational motion of a screw shaft part and linear motion of a displacement part to preferably generate attenuation force, with a simple structure.SOLUTION: A suspension device 10 has a screw shaft part 18 and a displacement part 15, and includes a feed screw mechanism part 20 capable of mechanically converting between rotational motion of the screw shaft part 18 and linear motion of the displacement part 15. Also, the suspension device 10 includes a motor 22 connected so as to impart rotational torque to the screw shaft part 18, and a housing member housing the displacement part 15 in a slidable manner. The suspension device 10 is configured such that a rotational shaft Sof the screw shaft part 18 and central shafts O, Oare arranged so as to deviate to each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a suspension device that attenuates a load such as vibration or impact.

  The suspension device is applied to a vehicle, for example, and attenuates vibrations and impacts applied to the vehicle to improve the ride comfort. In recent years, as this type of suspension device, as disclosed in FIG. 6 of Patent Document 1, a vehicle suspension device (electromagnetic suspension) that includes a feed screw mechanism and a motor and generates a damping force by the electromagnetic action of the motor. Also called).

  The feed screw mechanism portion disclosed in FIG. 6 of Patent Document 1 includes a screw shaft portion that is mechanically connected to a motor and is rotatable around a rotation shaft, and is screwed into the screw shaft portion and linearly along the rotation shaft direction. And a displaceable displacement part (nut). When the suspension device receives a load from the outside, the displacement portion linearly moves relative to the screw shaft portion, and rotates the screw shaft portion along with the straight movement. The motor generates rotational torque that suppresses rotational movement by transmitting rotation from the screw shaft portion. Thereby, the rectilinear movement of the displacement part is suppressed, and the load applied to the suspension device is attenuated.

JP2013-244841A

  By the way, as described above, it is difficult for the suspension device that generates the damping force by the feed screw mechanism portion to generate the damping force only in the displacement portion, particularly when a large load is suddenly applied. That is, the motor applies a large rotational torque in response to a large load, but this rotational torque is not converted only to the linear movement of the displacement portion but is transmitted to other configurations. As a result, the motor and the suspension device itself rotate around the axis of the screw shaft portion, affecting the configuration around the suspension device, and the linear movement of the displacement portion is reduced and smooth damping is not performed. Inconvenience arises.

  Here, as measures against the above inconvenience, a mechanism such as a linear spline is added between the feed screw mechanism and the housing member, or the motor or the suspension device itself is attached to the vehicle body via a rubber mount or a bush. Can be considered. However, when these configurations are employed, another problem such as an increase in manufacturing cost or a change in vibration transmission characteristics due to a rubber mount or a bush arises.

  The present invention has been made in view of the above-described circumstances, and improves the conversion efficiency between the rotational motion of the screw shaft portion and the linear motion of the displacement portion with a simple configuration to generate a good damping force. An object of the present invention is to provide a suspension device that can perform the above.

  In order to achieve the above object, the present invention includes a screw shaft portion and a displacement portion disposed on an outer peripheral surface of the screw shaft portion, and a rotational motion of the screw shaft portion and a rectilinear motion of the displacement portion. A feed screw mechanism portion that can be mechanically converted, a motor connected to the screw shaft portion so that rotational torque can be applied, a housing member that fixes the motor and slidably houses the displacement portion, The suspension device includes: a rotation shaft of the screw shaft portion and a center axis of the displacement portion that are shifted from each other.

  According to the above, the suspension device has a simple configuration in which the rotation shaft of the screw shaft portion and the center axis of the displacement portion are arranged so as to be shifted. Can be improved. That is, even if the displacement portion and the screw shaft portion work to receive a rotational torque of the motor and relatively rotate, the displacement portion and the screw shaft portion come into contact with the housing member that fixes the motor and the rotation thereof is restricted or suppressed. Accordingly, the rotational torque of the screw shaft portion is efficiently converted into the linear movement of the displacement portion, and the displacement portion can be favorably displaced, and the rotation of the suspension device itself and the motor due to the rotational torque can be prevented or suppressed. it can. In addition, the suspension device does not require any other configuration for suppressing rotation, and thus an increase in manufacturing cost can be suppressed. Furthermore, since the suspension device can suppress a change in vibration transmission characteristics due to the addition of another configuration, it is possible to prevent deterioration in the riding comfort of the vehicle.

  In this case, it is preferable that the displacement portion includes a bearing portion capable of rotatably supporting a connection member for attaching the suspension device to the outside.

  As described above, since the displacement portion rotatably supports the connection member by the bearing portion, the connection member has a structure in which no rotational force (twist) is applied by the displacement portion eccentric from the central axis. Thereby, since it is suppressed that a displacement part curves with respect to a screw shaft part, the sliding resistance of a displacement part can be reduced and it can be displaced more smoothly.

  According to the present invention, the suspension device can generate a damping force satisfactorily by improving the conversion efficiency between the rotational motion of the screw shaft portion and the rectilinear motion of the displacement portion with a simple configuration.

1 is a side sectional view showing an overall configuration of a suspension device according to an embodiment of the present invention. It is side surface sectional drawing which expands and shows the housing | casing, nut, and screw shaft part of the suspension apparatus of FIG. It is the III-III sectional view taken on the line of FIG. It is side surface sectional drawing which shows the whole structure of the suspension apparatus concerning a modification.

  Hereinafter, preferred embodiments of a suspension apparatus according to the present invention will be described in detail with reference to the accompanying drawings.

  The suspension device 10 according to the present embodiment is configured as an external force relaxation device for a vehicle. That is, as shown in FIG. 1, the suspension device 10 is provided between the vehicle body 12 and the wheel 14 to relieve external force (vibration, impact, etc.) from the unevenness of the road surface and press the wheel 14 against the road surface. Improve ride comfort and handling stability. In addition, the installation object of the suspension apparatus 10 is not limited to a vehicle, For example, it can apply to arbitrary places as a damping device which suppresses a vibration.

  In particular, the suspension device 10 has a structure that electromagnetically generates a damping force rather than a conventionally known relaxation structure using a spring or hydraulic pressure. Specifically, a feed screw mechanism portion 20 including a nut 16 (displacement portion 15) and a screw shaft portion 18 and a motor 22 mechanically connected to the screw shaft portion 18 are provided.

The nut 16 is disposed on the outer peripheral surface of the screw shaft portion 18 and linearly moves along the direction of the rotation axis S _r of the screw shaft portion 18. The screw shaft portion 18 rotates around the rotation axis S _r by converting the straight movement of the nut 16 into a rotation motion. The rotation of the screw shaft portion 18 is transmitted to the motor 22 via the rotation transmission mechanism portion 24 of the suspension device 10, and an induced electromotive force is generated in the motor 22. A controller 26 is connected to the motor 22, and the controller 26 generates a rotational torque that rotates the motor 22 in the reverse direction based on the induced electromotive force. The screw shaft portion 18 receives this rotational torque from the motor 22 to attenuate the straight movement of the nut 16. As a result, the suspension device 10 relaxes the vertical movement of the entire device. Hereinafter, the configuration of the suspension device 10 will be described in more detail.

  The suspension device 10 includes a housing 28 that is long in the vertical direction as a whole and that can be expanded and contracted (moved up and down) in the vertical direction in order to accommodate the feed screw mechanism portion 20 described above. The upper end portion of the housing 28 is attached to a suspended portion of the vehicle body 12 (for example, a vehicle body frame or a suspended portion of the body). A lower end portion of the housing 28 is attached to a drive transmission portion 14 a (for example, a driven gear or a shaft) that transmits a rotational driving force to the wheel 14. In FIG. 1, the suspension device 10 is illustrated in an applied state extending in the vertical direction, but the suspension device 10 may be installed in a posture such as an inclination or a lateral direction.

  The casing 28 is connected to an inner cylinder 30 (inner tube) connected to a suspended portion of the vehicle body 12, an outer cylinder 32 (outer tube) that slidably accommodates the inner cylinder 30, and a lower side of the outer cylinder 32. And a housing 34 connected to the drive transmission portion 14 a of the wheel 14. That is, the elasticity of the housing 28 is realized by the relative movement of the inner cylinder 30 and the outer cylinder 32.

  The inner cylinder 30 of the suspension device 10 constitutes a part of the displacement portion 15 that can be displaced integrally with the nut 16 of the feed screw mechanism portion 20. The inner cylinder 30 is formed in a circular cross section and has a long cylindrical shape in the axial direction. A hollow portion 36 having a circular cross section is formed inside the inner cylinder 30, and a closing portion 38 that closes the hollow portion 36 is provided at the upper end portion of the inner cylinder 30.

The hollow portion 36 is set at a position slightly deviated from the central axis O _i of the inner cylinder 30. That is, the axial center part S _i of the hollow part 36 extends in parallel with the central axis O _i from the lower end of the inner cylinder 30 to the closing part 38 while being shifted from the central axis O _i of the inner cylinder 30. The effect of the displacement of the hollow portion 36 will be described in detail later.

A connecting member 40 that connects the suspended portion of the vehicle body 12 and the suspension device 10 is inserted into the central portion of the closing portion 38 (the central axis O _i of the inner cylinder 30). The connection member 40 is formed in a rod shape, and as shown in FIG. 2, a drop-off prevention mechanism 42 (such as a flange) that prevents the connection member 40 from being detached when inserted into the closing portion 38 is provided.

  The closing portion 38 includes a connection member bearing 44 that rotatably supports the connection member 40 on the inner peripheral surface of the insertion portion of the connection member 40. In FIG. 2, a ball bearing is applied as the connecting member bearing 44, but the structure of the bearing is not particularly limited. For example, various configurations such as a roller bearing, a slide bearing, and a magnetic bearing can be used. Applicable.

  On the other hand, the outer cylinder 32 of the suspension device 10 is configured as a housing member that houses the feed screw mechanism 20 as shown in FIG. The outer cylinder 32 has an axial length similar to that of the inner cylinder 30 and has a cylindrical shape that is slightly larger in diameter than the inner cylinder 30. Inside the outer cylinder 32, an accommodation space 46 that is formed by an inner circumferential surface 32 a that is slightly larger than the outer diameter of the inner cylinder 30 and penetrates the upper and lower sides of the outer cylinder 32 is formed. The lower side of the accommodation space 46 is closed by fixing the outer cylinder 32 to the housing 34 and the screw shaft portion 18 of the feed screw mechanism portion 20 is inserted. The accommodating space 46 accommodates the displacement portion 15 (the nut 16 and the inner cylinder 30) together with the screw shaft portion 18, and the inner cylinder 30 is exposed from the upper side opening 46a of the outer cylinder 32 so as to freely advance and retract.

As shown in FIG. 2, on the upper side of the accommodation space 46, a metal outer cylinder side bush 47 that slightly protrudes radially inward from the inner circumferential surface 32a and circulates around the inner circumferential surface 32a is arranged. Yes. A plurality (two in FIG. 2) of outer cylinder side bushes 47 are provided at different positions in the axial direction of the outer cylinder 32. The two outer cylinder side bushes 47 guide the sliding of the inner cylinder 30 while maintaining the parallel state of the central axis O _o of the outer cylinder 32 and the central axis O _i of the inner cylinder 30.

  As described above, the feed screw mechanism portion 20 accommodated in the outer cylinder 32 includes the nut 16 and the screw shaft portion 18, and converts the linear motion of the nut 16 and the rotational motion of the screw shaft portion 18. The nut 16 is a displacement portion 15 that is connected and fixed to the lower end portion of the inner cylinder 30 and that integrally displaces the inner cylinder 30 with respect to the screw shaft portion 18. For this reason, the outer shape of the outer peripheral surface of the nut 16 is formed to match the outer shape of the outer peripheral surface of the inner cylinder 30.

The nut 16 has a cylindrical penetrating portion 16a extending along the axial direction, and a ball holding member 48 is tightly held on an inner peripheral surface constituting the penetrating portion 16a. Penetrating portion 16a is provided at a slightly deviated position from the center axis O _n of the nut 16, in a connected state of the inner cylinder 30 and the nut 16, the axial portion S _n matches the axial center S _i of the hollow 36 Are set to be continuous.

  Inside the ball holding member 48, there is provided an insertion hole 50 that is formed to penetrate up and down with an inner diameter that substantially matches the outer diameter of the screw shaft portion 18. A plurality of balls 52 (rolling elements) are held on the inner peripheral surface of the ball holding member 48 (nut 16) constituting the insertion hole 50 so as to be able to roll and not drop off. The ball 52 slightly separates the nut 16 and the screw shaft 18 and smoothly displaces the nut 16 with respect to the screw shaft 18 by rolling.

  A nut-side bush 54 that slightly protrudes radially outward is provided on the outer peripheral surface of the nut 16. The nut-side bush 54 maintains the posture of the nut 16 and the inner cylinder 30 in the same manner as the outer cylinder-side bush 47. Further, the nut side bush 54 is hooked on the outer cylinder side bush 47 to prevent the inner cylinder 30 from being detached from the outer cylinder 32.

  On the other hand, the screw shaft portion 18 is rotatably supported inside the lower housing 34 and is a solid bar-like member extending from the housing 34 to the vicinity of the upper side opening 46a of the outer cylinder 32 (or a middle portion of the outer cylinder 32). It is. A thread groove 56 is spirally cut out on the outer peripheral surface of the screw shaft portion 18. The cross section of the thread groove 56 is formed in an arc shape (triangular shape, gothic arch shape, etc.), and is set to a relatively wide groove width.

The screw shaft portion 18 is inserted into the insertion hole 50 of the nut 16 and the hollow portion 36 of the inner cylinder 30 in the assembled state of the suspension device 10. In this state, a part of the plurality of balls 52 accommodated in the nut 16 enters the screw groove 56 of the screw shaft portion 18. The suspension apparatus 10, the center axis Oi of the housing 28 (the inner cylinder 30 and the outer cylinder 32), O _o and at a position deviated to the center axis O _n of the nut 16, the rotation axis S _r of the threaded shaft portion 18 ( The screw shaft portion 18 is rotatably held by the housing 34. The screw shaft portion 18 rotates relative to the nut 16 when the plurality of balls 52 roll obliquely along the screw groove 56 along with the straight movement of the nut 16. In addition, the screw shaft portion 18 rotates around the shaft center when the rotational torque of the motor 22 is transmitted, and generates a damping force that suppresses the straight movement of the nut 16.

  A housing 34 that accommodates and holds the screw shaft portion 18 constitutes a housing 28 in a lower portion of the suspension device 10, and the suspension device 10 is attached to the wheel 14 side. The housing 34 includes a screw shaft side holding portion 58 that houses a part of the screw shaft portion 18 and a motor side holding portion 60 that houses a part of the motor 22. The screw shaft side holding portion 58 and the motor side holding portion 60 may be integrally formed as shown in FIG. 1, or may be formed separately and connected by connecting means such as screwing.

  The screw shaft side holding portion 58 is formed in a cylindrical shape that matches the outer diameter of the outer cylinder 32 and has a holding space 62 inside. An upper bottom portion 64 that covers the holding space 62 is provided on the upper portion of the screw shaft portion side holding portion 58, and a through port 64 a through which the screw shaft portion 18 passes is formed in the upper bottom portion 64. The screw shaft side holding portion 58 closes the holding space 62 with a lower bottom portion 66 having a sufficient thickness, and a lower portion of the lower bottom portion 66 has an annular shape connected to the drive transmission portion 14a of the wheel 14. The attachment portion 68 is integrally formed.

  On the holding space 62 side of the lower bottom portion 66, a concave portion 66a that accommodates and holds the lower end portion of the screw shaft portion 18 is provided. A first screw shaft portion bearing 70 that rotatably supports the screw shaft portion 18 is provided on the inner peripheral surface of the recess 66a. Furthermore, the screw shaft portion side holding portion 58 projects the intermediate wall portion 72 at a position spaced upward from the lower bottom portion 66 (a position near the upper bottom portion 64). Is provided with a second screw shaft bearing 74. The first and second screw shaft portion bearings 70 and 74 support the proximal end side of the screw shaft portion 18, thereby suppressing the shake on the upper side of the screw shaft portion 18 and promoting the rotation. The structure of the first and second screw shaft bearings 70 and 74 is not particularly limited, and the structure described in connection member bearing 44 can be selected as appropriate.

  A screw shaft portion side pulley 76 that is a part of the rotation transmission mechanism portion 24 is firmly fixed to the screw shaft portion 18 existing in the gap between the intermediate wall portion 72 and the lower bottom portion 66. An endless belt 78 is wound around the side periphery of the screw shaft side pulley 76. The belt 78 constitutes a part of the rotation transmission mechanism portion 24 that transmits a rotational force between the screw shaft portion 18 and the motor 22.

  On the other hand, the motor side holding portion 60 is formed in a cylindrical shape having a larger diameter than the screw shaft portion side holding portion 58 and shorter in the axial direction. A motor housing space 80 that houses a part of the motor 22 is provided inside the motor side holding portion 60, and a bottom wall 82 that closes the motor housing space 80 is formed at the lower end side thereof. The motor side holding part 60 fixes and holds the main body part 90 of the motor 22 inserted into the motor housing space part 80 from the upper end opening. A rotating shaft bearing 84 that rotatably supports the rotor 88 of the motor 22 is provided on the bottom wall 82 of the motor side holding portion 60.

  A motor-side pulley 86 is firmly fixed to the rotor 88 existing in the motor housing space 80. The motor-side pulley 86 is the rotation transmission mechanism 24 that transmits the rotational force between the screw shaft 18 and the motor 22, and a belt 78 is wound around the side peripheral edge of the motor-side pulley 86. The rotation transmission mechanism 24 is not limited to the above configuration (screw shaft side pulley 76, belt 78, and motor side pulley 86), and can adopt various structures, for example, a structure in which a plurality of gears are combined. But you can.

  The motor 22 includes a rotor 88 and a main body 90 having a rotation mechanism 90 a that houses a part of the rotor 88 and electromagnetically rotates the rotor 88. The rotor 88 of the motor 22 penetrates through the motor side holding portion 60 and is exposed from the lower side of the motor side holding portion 60 while being pivotally supported by the rotary shaft bearing 84. As for the main-body part 90, the surrounding wall by which the rotor 88 protrudes is firmly fixed to the motor side holding part 60 by predetermined connection means, such as screwing and adhesion | attachment.

  The rotation mechanism 90a in the main body 90 includes, for example, a rotor attached to the rotor 88 and a stator that generates a rotational moment in the rotor. Further, in the rotation mechanism 90a, the stator generates an induced electromotive force due to the rotation of the rotor. A controller 26 is electrically connected to the motor 22, and the induced electromotive force generated in the main body 90 is output to the controller 26.

  The control unit 26 is configured as, for example, a computer having a calculation unit, a storage unit, and an input / output unit, and has a function of controlling the rotational drive of the motor 22 based on the induced electromotive force from the motor 22. When detecting the induced electromotive force of the motor 22, the control unit 26 supplies power to the motor 22 so as to generate a rotational torque in a direction opposite to the rotational direction of the rotor 88. The control unit 26 applies a rotational torque to the rotor 88 in proportion to the induced electromotive force. For this reason, when the rotor 88 rotates vigorously, the control unit 26 controls to apply a high rotational torque in accordance with the rotation of the rotor 88.

  The control unit 26 may be configured to rotate the motor 22 by adopting a predetermined electric circuit without being configured as a computer. The control unit 26 may be configured to be connected to a sensor (for example, a gravity sensor, not shown) that detects an external force, and to control the rotational torque of the motor 22 based on a detection signal of the sensor. That is, the suspension device 10 can be configured to actively generate a damping force in accordance with a control instruction from the control unit 26 regardless of the rotation of the screw shaft portion 18.

The suspension device 10 according to the present embodiment is basically configured as described above. Next, the axial center S _n of the displacement portion 15 (insertion hole 50 of the cavity 36 and the inner cylinder 30 of the nut 16), the rotation axis S _r of S _i and the screw shaft portion 18, the nut 16, the inner cylinder 30 and The positional deviation of the outer cylinder 32 from the central axes O _n , O _i , and O _o will be described in detail, and the effects thereof will be described.

The suspension system 10, as shown in FIGS. 2 and 3, shifting by the shape of the displacement portion 15 and the housing 28, the center axis O _n of the rotary shaft S _r and the displacement portion 15 of the threaded shaft portion 18, the O _i Arranged. That is, the nut 16 and the inner cylinder 30 are connected and fixed up and down with the same outer shape (circular cross section), and the center axes O _n and O _i of each other coincide. On the other hand, displacement axial center S _i of the cavity 36 relative to the center axis O _i of the inner cylinder 30 by a distance D, and the axial center S _n of the insertion hole 50 with respect to the center axis O _n of the nut 16 intervals It is shifted by D.

The screw shaft portion 18 is inserted into the insertion hole 50 and the cavity portion 36, and the rotation axis S _r is disposed so as to coincide with the shaft center portions S _n and S _i of the insertion hole 50 and the cavity portion 36. Therefore, the rotation axis S _r of the threaded shaft portion 18 is also the central axis O _n of the displacement portion 15, will be offset from O _i by the distance D, also eccentrically by a distance D from the center axis O _o of the outer tube 32. The distance D is set larger than the distance (gap G) between the outer peripheral surface of the displacement portion 15 and the inner peripheral surface of the outer cylinder 32. Thereby, when the displacement part 15 receives the rotational torque of the screw shaft part 18, it contacts the inner peripheral surface 32a of the outer cylinder 32 even if a rotation effect | action works. That is, the relative rotation of the displacement portion 15 and the screw shaft portion 18 is restricted (or suppressed).

  Hereinafter, with reference to FIG. 1, the operation of the present suspension device 10 will be described in the case where a large load is suddenly applied from the lower side (wheel 14 side) upward (arrow A1 direction) due to the unevenness of the road surface. I will explain it with an example. In this case, the inner cylinder 30 and the nut 16 fixed to the vehicle body 12 side are displaced downward (in the direction of the arrow A2) relative to the outer cylinder 32 and the screw shaft portion 18. Along with the displacement of the nut 16, the screw shaft portion 18 into which the nut 16 is screwed rotates, for example, in a clockwise direction (arrow B1 direction: see also FIG. 3). The rotation of the screw shaft portion 18 is transmitted to the rotor 88 of the motor 22 via the rotation transmission mechanism portion 24, and the motor 22 outputs an induced electromotive force to the control portion 26 as the rotor 88 rotates.

  The control unit 26 performs control to appropriately supply power to the motor 22 based on the induced electromotive force, and generates a counterclockwise rotational torque (reaction force) for the rotor 88. The control unit 26 applies a relatively large rotational torque to a large load, and this rotational torque is transmitted to the screw shaft portion 18 via the rotation transmission mechanism unit 24. The screw shaft 18 applies a rotational torque in the counterclockwise direction (arrow B2 direction), thereby displacing the nut 16 in the arrow A2 direction, that is, generating a damping force in the linear movement of the nut 16.

At this time, the feed screw mechanism portion 20 not only converts a large rotational torque into a linear motion of the nut 16 but also acts to relatively rotate the nut 16 and the screw shaft portion 18. For this reason, as shown in FIG. 3, the nut 16 _{tends to} rotate around the rotation axis Sr of the screw shaft portion 18 (arrow B2 direction). Conversely, the screw shaft portion 18 acts to rotate in the direction opposite to the rotation direction of the nut 16. However, since the rotation axis S _r of the screw shaft portion 18 is deviated from the center axes O _n and O _{i of the} displacement portion 15 (that is, the center axis O _o of the outer cylinder 32), as shown by a thick line in FIG. The nut 16 comes into contact with the inner peripheral surface 32a of the outer cylinder 32, and the relative rotation between the nut 16 and the screw shaft portion 18 is restricted.

That is, the relative rotation between the nut 16 and the screw shaft portion 18 is locked to the outer cylinder 32 due to the displacement of the rotation shaft _Sr of the screw shaft portion 18, so that the nut 16 eventually performs almost all the rotational movement of the screw shaft portion 18. Convert to linear motion. As a result, the suspension device 10 can generate a damping force with respect to the nut 16 more reliably and can absorb and attenuate the load applied to the vehicle.

  The displacement portion 15 slightly rotates until it comes into contact with the inner peripheral surface 32 a of the outer cylinder 32 due to the rotational torque of the screw shaft portion 18, that is, receives a bending stress from the screw shaft portion 18. The suspension device 10 rotatably supports the connection member 40 by a connection member bearing 44 so that the bending stress is not transmitted to the connection member 40 connected to the suspended portion of the vehicle body 12 (see FIG. 2). As a result, since the connecting member 40 is continuously suspended from the vehicle body 12 and the displacement portion 15 is restrained from bending with respect to the screw shaft portion 18, the sliding resistance of the displacement portion 15 is reduced and smoother. Can be displaced.

  The actual value of the distance D, which is the displacement amount of the screw shaft portion 18, depends on the size of the suspension device 10, but in the suspension device 10 applied to a vehicle, for example, a range of 2 mm to 10 mm is preferable and more preferable. Is preferably set within a range of 3 to 5 mm. When the distance D is less than 2 mm, the distance D becomes smaller than the gap G, and it becomes difficult to sufficiently obtain the effect of shifting the screw shaft portion 18. If the distance D is greater than 10 mm, the linear movement of the displacement portion 15 is affected, and it becomes difficult to move smoothly.

As described above, according to the suspension device 10 according to the present embodiment, the center axis O _n of the displacement unit 15 and the rotating shaft S _r of the threaded shaft portion 18, a simple configuration that arranged offset and O _i, The conversion efficiency between the rotational motion of the screw shaft portion 18 and the rectilinear motion of the displacement portion 15 can be improved. That is, even if the displacement portion 15 and the screw shaft portion 18 work to receive a rotational torque of the motor 22 and relatively rotate, the displacement portion 15 and the screw shaft portion 18 come into contact with the casing 28 that fixes the motor 22 and the rotation thereof is restricted. Or suppressed. Therefore, the rotational torque of the screw shaft portion 18 is efficiently converted into the linear motion of the displacement portion 15, and the displacement portion 15 can be displaced favorably, and the rotation of the suspension device 10 itself and the motor 22 due to the rotational torque is prevented. Or it can be suppressed. In addition, since the suspension device 10 does not require another configuration for suppressing rotation, an increase in manufacturing cost can be suppressed. Furthermore, since the suspension device 10 can suppress a change in vibration transmission characteristics due to the addition of another configuration, it is possible to prevent deterioration in the riding comfort of the vehicle.

The suspension device 10 according to the present invention is not limited to the above-described embodiment, and various modifications and applications can be taken. For example, the suspension device 10, if misaligned axial center S _n of the insertion hole 50 of the nut 16, it is possible to suppress the rotation of the nut 16 and the inner cylinder 30. Therefore, if the hollow portion 36 of the inner cylinder 30 is formed large enough to allow the screw shaft portion 18 to enter, the axial center portion S _i of the hollow portion 36 is made to coincide with the central axis O _i of the inner tube 30. Also good.

The suspension device 10A according to the modified example shown in FIG. 4 is different from the suspension device 10 in that the inner cylinder 30 is connected to the wheel 14 side, and the outer cylinder 32 and the housing 34 are connected to the vehicle body 12 side. Different. Further, the screw shaft portion 18 of the suspension device 10 </ b> A is directly connected to the rotor 92 (armature) of the motor 22 on the upper side of the housing 28, and is configured to apply rotational torque by the magnetism of the stator 94. In this case, by rotating shaft S _r of the threaded shaft portion 18 of the feed screw mechanism 20 is arranged to be shifted relative to the center axis O _n of the nut 16, the nut 16 the rotational torque applied to the screw shaft portion 18 In addition, it can be efficiently converted into the straight movement of the inner cylinder 30.

  In short, the motor 22 that applies rotational torque to the screw shaft portion 18 can be freely designed in its mounting position and structure. It is also possible to use the suspension device 10 by changing the top and bottom in the reverse direction.

Furthermore, the suspension device 10A ′ may be configured as a braking suppression device having a damping member 96 (coil spring or the like), as indicated by a two-dot chain line in FIG. In other words, the feed screw mechanism 20 and the motor 22, which are structures inside the housing 28, adjust the relative displacement positions of the inner cylinder 30 and the outer cylinder 32 to control the overall length of the damping member 96, so-called shock absorber. Function as. Thus, even when functioning as a shock absorber, by rotating shaft S _r of the threaded shaft portion 18 of the feed screw mechanism 20 is arranged to be shifted relative to the center axis O _n, O _i of the displacement unit 15 The displacement part 15 can be displaced favorably. Accordingly, the suspension device 10A ′ can perform highly accurate damping control.

  In the above description, the present invention has been described with reference to preferred embodiments. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention. Yes.

DESCRIPTION OF SYMBOLS 10, 10A, 10A '... Suspension apparatus 15 ... Displacement part 16 ... Nut 18 ... Screw shaft part 20 ... Feed screw mechanism part 22 ... Motor 28 ... Housing 30 ... Inner cylinder 32 ... Outer cylinder 40 ... Connection member 44 ... Connection member use bearings _{O i, O n, O o} ... center axis _{S i, S n, S r} ... axial center

Claims (2)

A feed screw mechanism portion having a screw shaft portion and a displacement portion disposed on an outer peripheral surface of the screw shaft portion, and capable of mechanically converting the rotational motion of the screw shaft portion and the linear movement of the displacement portion;
A motor connected to the screw shaft portion so as to be able to apply a rotational torque;
A suspension device that includes a housing member that slidably houses the displacement portion while fixing the motor,
The suspension device, wherein the rotation shaft of the screw shaft portion and the central axis of the displacement portion are shifted from each other. The suspension device according to claim 1, wherein
The said displacement part is provided with the bearing part which can rotatably support the connection member for attaching the said suspension apparatus to the exterior. The suspension apparatus characterized by the above-mentioned.

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