JP2006057815A - Suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber capable of reducing moment of inertia and generating damping force even at the time of minute stroke. <P>SOLUTION: In this shock absorber provided with a movement conversion mechanism H for converting linear movement into rotary movement and a motor M to which the rotary movemet is transmitted, an output shaft S of the motor M and a rotation side member 2 of the movement conversion mechanism H are rotationally locked and connected mutually, and an elastic body 10 is arranged between the output shaft S and the rotation side member 2. In the concrete, the output shaft S and the rotation side member 2 are spline-connected, and the elastic body 10 is arranged between mutual spline teeth 5 and 9. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a suspension device that uses torque generated by a motor as a damping force that suppresses linear motion of a motion conversion mechanism.

  This type of shock absorber includes a ball screw nut, a screw shaft screwed to the ball screw nut, and a motor to which an output shaft is coupled to the screw shaft through a coupling. By rotating the screw shaft to generate an induced electromotive force in the motor winding to generate an electromagnetic force in the motor, the torque output by the motor due to the electromagnetic force is used as the damping force generation source (for example, , See Patent Document 1).

In addition, in this shock absorber, in addition to the torque generated by the motor, the adverse effect of the moment of inertia of the rotor and screw shaft of the electromagnetic motor that affects the generated damping force, that is, increases in proportion to the rotational angular acceleration. When the moment of inertia is this shock absorber, the mass of the motor, etc. is large, so it always affects the damping force generated by the shock absorber when the rotational speed changes, and its control is not easy. In order to remove the adverse effects that worsen, the coupling is composed of a member connected to the output shaft side, a member connected to the screw shaft side, and an elastic body interposed between both members. The influence of the moment of inertia when vibrating with a large force is alleviated by the elastic body to improve the riding comfort in the vehicle.
Japanese Unexamined Patent Publication No. 2004-11753 (paragraph numbers 0067 to 0068, FIGS. 1 and 4)

  The above-described shock absorber is very useful in that the influence of the moment of inertia on the generated damping force can be reduced as described above. However, the following problems may be pointed out.

  That is, in the conventional shock absorber, the elastic body in the coupling is elastically deformed to reduce the influence of the moment of inertia, but the elastic body has a large volume and the shock absorber vibrates with a small stroke. In some cases, the vibration is absorbed by the elastic deformation of the elastic body, and the damping force may not be generated by the torque of the motor.

  Then, in the conventional shock absorber, in the minute vibration region, it takes a long time until the vibration is attenuated, and there is a fear that the riding comfort in the vehicle is deteriorated.

  In order to prevent the above adverse effects, the screw shaft and the output shaft may be connected using, for example, a spline or a key without using an elastic body. However, in such a connection, there is always a slight backlash. In addition, there is an adverse effect of generating abnormal noise due to metal contact during vibration of the shock absorber, and the relaxation of the moment of inertia is not achieved at all.

  Accordingly, the present invention was devised in order to improve the above-mentioned problems, and an object of the present invention is to provide a shock absorber that can reduce the moment of inertia and can generate a damping force even at a minute stroke. That is.

  In order to achieve the above object, the present invention provides a motion conversion mechanism that converts linear motion into rotational motion, and a shock absorber that includes a motor to which the rotational motion is transmitted. The rotation side member is connected to the rotation side member while being prevented from rotating, and an elastic body is disposed between the output shaft and the rotation side member.

 According to the present invention, since the elastic body is disposed between the output shaft and the rotation side member, the amount of elastic deformation is small compared to the elastic body of the conventional shock absorber, and the shock absorber has a minute stroke. Even so, since the rotational motion of the rotary member is transmitted to the output shaft of the motor, the shock absorber can generate a damping force even with a small stroke.

  In addition, due to the arrangement of the elastic body, the torque of the output shaft is not directly transmitted to the rotating side member, and unnecessary damping force is generated at the initial stage of expansion / contraction of the shock absorber due to the moment of inertia as in the conventional shock absorber. This reduces the problem of causing the vehicle occupant to perceive a jerky feeling, thereby improving the riding comfort of the vehicle.

 Further, since an elastic body is disposed between the output shaft and the rotation side member, it is possible to prevent the output shaft and the rotation side member from coming into contact with the metal, so that there is no problem that abnormal noise occurs.

 When the motor side is connected to the vehicle body side member of the vehicle, even if the rotation side member is vibrated in the axial direction by vibration input from the road surface while the vehicle is running, the elastic body and the surface of the rotation side member Since there is also an effect that the vibration of the rotation side member is attenuated by generating friction between the rotation side member, the vibration of the rotation side member can be made difficult to be transmitted to the vehicle body side, and thereby the vibration of the rotation side non-member is transmitted to the vehicle body. This also has the effect of reducing the volume of abnormal noise caused by this.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view conceptually showing a shock absorber according to an embodiment. FIG. 2 is a cross-sectional view of the connecting portion between the output shaft of the motor and the rotation side member. FIG. 3 is a longitudinal sectional view conceptually showing a shock absorber according to another embodiment.

  As shown in FIG. 1, the shock absorber D <b> 1 in one embodiment basically includes a motion conversion mechanism H that converts linear motion into rotational motion, and a motor M that transmits the rotational motion. Furthermore, in the case of this embodiment, the motion conversion mechanism H is composed of a ball screw nut 1 and a screw shaft 2 screwed into the ball screw nut 1, and the axial direction of the ball screw nut 1 and the screw shaft 2. Is converted into a rotational motion of the screw shaft 2, and the rotational motion of the screw shaft 2 is transmitted to the output shaft S of the motor M, so that an induced electromotive force is applied to a winding (not shown) in the motor M. By generating energy by causing the motor M to regenerate energy, torque that resists rotation of the output shaft S caused by this electromagnetic force is suppressed and the rotational movement of the screw shaft 2 is suppressed. Damping force to suppress linear motion and It is to use this in.

  Further, as described above, the shock absorber D1 not only regenerates the kinetic energy of the relative linear motion in the axial direction of the ball screw nut 1 and the screw shaft 2 to generate a damping force, but also actively activates the motor M. In this case, the buffer D1 also functions as an actuator.

 The detailed structure will be described below. The screw shaft 2 is formed in a cylindrical shape, a spiral screw groove 3 is formed on the outer periphery thereof, and a hole 4 opened from the upper end is provided at the upper end of the screw shaft 2 in FIG. Outer spline teeth 5 are formed on the inner periphery of the hole 4.

  The ball screw nut 1 to be screwed onto the screw shaft 2 is provided with a spiral ball holding portion (not shown) on the inner periphery thereof so as to coincide with the spiral screw groove 3 of the screw shaft 1. A plurality of balls (not shown) are arranged in the ball holding portion, and a passage (not shown) communicates both ends of the ball holding portion so that the ball can circulate inside the ball screw nut 1. (Not shown), and when the ball screw nut 1 is screwed to the screw shaft 2, the ball of the ball screw nut 1 is fitted into the helical screw groove 3 of the screw shaft 2. However, since the ball itself rotates due to the frictional force with the screw groove 3 of the screw shaft 2 as the screw shaft 2 rotates, a smooth operation is possible as compared with a mechanism such as a rack and pinion.

  As described above, when the screw shaft 2 is rotatably engaged with the ball screw nut 1 along the screw groove 3 and the screw shaft 2 moves linearly in the vertical direction in FIG. Since the ball screw nut 1 is fixed to the inner periphery of the upper end of the cylinder 7 connected to one of the vehicle body side member or the axle side member of the vehicle via the bracket 6, the rotation of the ball screw nut 1 in the circumferential direction is thereby performed. Therefore, the screw shaft 2 is forcibly driven to rotate.

  In other words, the motion conversion mechanism H converts the relative linear motion of the ball screw nut 1 and the screw shaft 2 in the axial direction into the rotational motion of the screw shaft 2, and in this embodiment, the rotation side member is the screw shaft. That means two.

  On the other hand, the motor M is composed of a frame 8, a stator (not shown) fixed in the frame 8, and a rotor provided rotatably in the frame 8. It is connected to the other of the vehicle body side member or the axle side member of the vehicle.

  Therefore, the shock absorber D1 in the present embodiment is interposed between the vehicle body side member and the axle side member of the vehicle by the motor M and the bracket 6.

  As the motor, various types of motors (for example, a brushless motor, a hysteresis motor, an induction motor, etc.) can be used as long as the damping force can be generated in the shock absorber D1, but those with high efficiency and high output can be used. preferable.

  An inner spline tooth 9 that meshes with an outer spline tooth 5 provided at the upper end of the screw shaft 2 is formed on the outer periphery of the tip that is the lower end in FIG. 1 of the output shaft S that is a part of the rotor of the motor M. Further, the elastic body 10 is coated on the surface of the inner spline teeth 9.

  As shown in FIG. 2, the tip of the output shaft S coated with the elastic body 10 as described above is inserted into the hole 4 of the screw shaft 2 with the inner spline teeth 9 and the outer spline 5 being aligned, The output shaft S and the screw shaft 2 are connected, and the output shaft S and the screw shaft 2 are prevented from rotating by the spline structure.

  At this time, the clearance between the inner spline teeth 9 of the output shaft S and the outer spline teeth 5 of the screw shaft 2 is set to such an extent that the surface of the elastic body 10 coated on the output shaft S side is slightly scraped. Since the shaft S is press-fitted into the screw shaft 2, the elastic body 10 is compressed at the time of insertion, so that the output shaft S and the screw shaft 2 can be connected so as not to cause backlash.

  That is, in the shock absorber D1 of the present embodiment, the gap between the output shaft S and the screw shaft 2 is denser in the elastic body 10 than in the normal spline structure, that is, the spline structure in which the elastic body 10 is not disposed. As a result, rattling is prevented.

  For example, resin or rubber can be used as the elastic body 10, and the elastic body 10 may be coated on the surface of the outer spline teeth 5, and the inner spline teeth 9 and the outer spline teeth 5 may be coated. Both surfaces can be coated.

  Further, for example, the elastic body 10 is made of a metal putty in which metal powder is mixed with resin or epoxy adhesive, and the output shaft S is inserted into the screw shaft 2, and then the elastic body 10 is connected to the output shaft S and the screw shaft 2. The elastic body 10 may be disposed between the output shaft S and the screw shaft 2.

  Furthermore, it is not necessary to coat the elastic body 10 on the entire surface of the inner spline teeth 9, and it is possible to coat only the surface that meshes with the outer spline teeth 5, but it is easier to coat the entire surface in terms of processing. Become.

 Now, in the shock absorber D1 configured as described above, as described above, the motor M is driven and / or by energy regeneration, or both, the axial direction between the ball screw nut 1 and the screw shaft 2 is increased. Although the relative linear motion between the vehicle body and the axle of the vehicle is attenuated by suppressing the relative linear motion, the elastic body 10 is disposed between the output shaft S and the screw shaft 2. Therefore, it is possible to prevent the screw shaft 2 from hitting the metal, so there is no harmful effect of generating abnormal noise.

 Moreover, since the elastic body 10 is disposed between the inner spline teeth 9 of the output shaft S and the outer spline teeth 5 of the screw shaft 2, the amount of elastic deformation thereof is larger than that of the elastic body of the conventional shock absorber. Even if the shock absorber D1 has a small stroke, the rotational motion of the screw shaft 2 is transmitted to the output shaft S of the motor M. Therefore, the shock absorber D1 can generate a damping force even with a small stroke. It is.

 Further, when the motor M side is connected to a vehicle body side member of the vehicle, the screw shaft 2 is driven by vibration input from the road surface while the vehicle is running, and the ball screw nut 1 is moved in the vertical direction in FIG. Even if it is vibrated in the direction, there is an effect that the friction between the elastic body 10 and the outer spline teeth 5 of the screw shaft 2 causes friction to damp the vibration of the screw shaft 2, so that the vibration of the screw shaft 2 is This makes it difficult to transmit the noise to the vehicle body, thereby producing an effect of reducing the abnormal sound volume even when the vibration of the screw shaft 2 is transmitted to the vehicle body.

  Further, due to the above-described arrangement of the elastic body 10, the torque of the output shaft S is not directly transmitted to the screw shaft 2, and the expansion and contraction of the shock absorber due to the inertia moment peculiar to the shock absorber D1 is the same as the conventional shock absorber. The generation of the initial unnecessary damping force can be reduced, and the problem of causing the vehicle occupant to perceive a jerky feeling is reduced, and the riding comfort in the vehicle is improved.

 It continues and demonstrates the buffer D2 in other embodiment. In addition, about the member similar to the buffer D1 in one Embodiment, suppose that the same code | symbol is attached | subjected and the detailed description shall be abbreviate | omitted.

 As shown in FIG. 3, the shock absorber D2 basically includes a ball screw nut 1 similar to that of the first embodiment, a screw shaft 2 screwed into the ball screw nut 1, and a ball screw nut. The shock absorber D2 in the other embodiment is different from the shock absorber D1 in one embodiment, and includes a screw shaft 2 and a ball screw nut. 1 is converted into a rotational motion of the ball screw nut 2, and the rotational motion of the ball screw nut 2 is transmitted to the output shaft S of the motor M to be wound in the motor M (not shown). The electromagnetic force is generated by causing the motor M to regenerate energy by generating an induced electromotive force, and torque that resists rotation of the output shaft S due to the electromagnetic force is applied to the rotational movement of the ball screw nut 1. Suppress screw shaft Advantage of the linear movement of the damping force for restricting.

 That is, the difference from the embodiment is that the ball screw nut 1 transmits the rotational motion to the output shaft S of the motor M, and this point will be described in detail. 20 is rotatably supported via ball bearings 21 and 22, and a gear 24 is provided on the outer periphery thereof.

 The gear 24 meshes with a gear 25 connected to the lower end in FIG. 3 of the output shaft S of the motor M, and the ball screw nut 1 is connected via a gear mechanism G constituted by the gears 24, 25. Of the motor M can be transmitted to the output shaft S of the motor M. In this embodiment, the motion conversion mechanism H2 includes all of the ball screw nut 1, the screw shaft 2, and the gear mechanism G. The rotation side member is a gear 25.

 A hole 26 is provided in the shaft center portion of the gear 25, and an outer serration tooth 27 is provided on the inner peripheral side of the hole 26, and the output shaft S is inserted into the hole 26. However, an inner serration tooth 28 is provided on the outer periphery of the lower end in FIG. 3 of the output shaft S, and the gear 25 and the output shaft S are engaged with the outer serration tooth 27 and the inner serration tooth 28, that is, serration. It is connected with the structure.

 A gap is provided between the outer serration tooth 27 and the inner serration tooth 28, and this gap has elasticity such as a metal putty made by mixing a resin and an epoxy adhesive with a metal component. The body 30 is filled, whereby the elastic body 30 is disposed between the output shaft S and the gear 25 which is the rotation side member.

 Even in the elastic body 30, as in the elastic body 10 of the embodiment, before connecting the output shaft S and the gear 25, one or both of the inner serration teeth 28 and the outer serration teeth 27 are connected in advance. It may be coated.

 Furthermore, in this other embodiment, the screw shaft 2 is connected to, for example, one of the vehicle body side member or the axle side member of the vehicle to restrict circumferential rotation, and the screw shaft 2 in the vertical direction in FIG. This linear motion can be converted into a rotational motion of the ball screw nut 1.

 In the case of this embodiment, the motor M is arranged and fixed to the side of the cylinder 20, and the upper end side of the cylinder 20 is connected to the other of the vehicle body side member or the axle side member of the vehicle, so that the shock absorber D2 is interposed between the vehicle body side member and the axle side member of the vehicle.

 Therefore, even in the shock absorber D2 in this other embodiment, the damping force can be generated in the same manner as the shock absorber D1 in the one embodiment, and the motor M is actively driven, so that the actuator Also works.

 In the motion conversion mechanism H2, the rotational motion of the ball screw nut 1 can be transmitted to the motor M via the gear mechanism G. However, the rotational motion is transmitted via a friction wheel mechanism or a belt mechanism. May be.

 Even in the shock absorber D2 in the other embodiment, the elastic body 30 is disposed between the output shaft S and the gear 25 which is the rotation side member, similarly to the shock absorber D1 in the one embodiment. Therefore, the metal contact between the output shaft S and the gear 25 can be prevented, so there is no problem that abnormal noise occurs.

 Moreover, since the elastic body 30 is disposed between the inner serration teeth 28 and the outer serration teeth 27, the amount of elastic deformation is small compared to the elastic body of the conventional shock absorber, and the shock absorber D2 is very small. Since the rotational motion of the gear 25 is transmitted to the output shaft S of the motor M even in the stroke, the shock absorber D2 can generate a damping force even with a minute stroke.

  Further, due to the arrangement of the elastic body 30 described above, the torque of the output shaft S is not directly transmitted to the ball screw nut 1 and, similarly to the conventional shock absorber, the shock absorber is caused by the inertia moment peculiar to the shock absorber D1. The generation of unnecessary damping force at the initial stage of expansion and contraction can be reduced, and the problem of making the vehicle occupant perceive a jerky feeling is reduced, and the riding comfort in the vehicle is improved.

  In each of the above-described embodiments, the spline structure and the serration structure are adopted as the rotation stopper. For example, the rotation is stopped by a key and a key groove, and one or both of the key and the key groove is elastic. It is also possible to coat the elastic body between the key and the key groove, and coat the elastic body not only on the key and key groove but also on the entire fitting part of the output shaft and screw shaft or gear. Or filling.

  Of course, a hole may be provided in the output shaft S of the motor, and a shaft provided on the screw shaft or gear may be inserted under the spline or serration structure.

  This is the end of the description of the embodiment of the present invention, but the scope of the present invention is of course not limited to the details shown or described.

It is a longitudinal cross-sectional view which shows notionally the shock absorber in one Embodiment. It is a cross-sectional view of the connection part of the output shaft of a motor, and a rotation side member. It is a longitudinal cross-sectional view which shows notionally the shock absorber in other embodiment.

Explanation of symbols

1 Ball screw nut 2 Screw shaft 3 Screw groove 4 Hole 5 Outer spline teeth 6 Brackets 7 and 20 Tube 8 Case 9 Inner spline teeth 10 and 30 Elastic body 10 Damping material 21 and 22 Ball bearings 24 and 25 Gear 26 Hole 27 Outer serration Teeth 28 Inner teeth D1, D2 Shock absorber H1, H2 Motion conversion mechanism M Motor S Output shaft

Claims (3)

In a shock absorber provided with a motion conversion mechanism that converts linear motion into rotational motion and the motor to which the rotational motion is transmitted, the motor output shaft and the rotation-side member of the motion conversion mechanism are connected to each other while being prevented from rotating. An elastic body is disposed between the output shaft and the rotation side member. 2. The buffer according to claim 1, wherein the output shaft and the rotation side member are prevented from rotating by spline coupling, and an elastic body is disposed between the spline of the output shaft and the spline of the rotation side member. vessel. 2. The buffer according to claim 1, wherein the output shaft and the rotation side member are prevented from rotating by serration coupling, and an elastic body is disposed between the serration of the output shaft and the serration of the rotation side member. vessel.

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