JP2006038146A - Electromagnetic shock absorber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress deflection of a ball screw shaft due to lateral force in an electromagnetic shock absorber.
In an electromagnetic shock absorber, an end projecting into a damper case 11 through a ball screw nut 30 of a ball screw shaft 40 is supported by a bearing 80, and a bearing holder 81 for holding the bearing 80 is provided. The damper case 11 is supported so as to be non-rotating and slidable.
[Selection] Figure 1

Description

  The present invention relates to an electromagnetic shock absorber.

As an electromagnetic shock absorber, as described in Patent Document 1, a ball screw shaft is screwed to a ball screw nut fixed to a damper case, a motor is coupled to the ball screw shaft, and the linear motion of the ball screw nut is This rotational motion is transmitted to the motor shaft and electromagnetic force is generated in the motor, and the torque that resists rotation of the motor shaft due to this electromagnetic force is converted to the linear motion of the ball screw nut. Some are used as damping force to suppress.
JP2003-343648

  In the electromagnetic shock absorber disclosed in Patent Document 1, the intermediate portion of the ball screw shaft is supported by a ball screw nut fixed to the damper case, but protrudes into the damper case through the ball screw nut of the ball screw shaft. It does not support the end part.

  For this reason, the ball screw shaft swings due to lateral force (an external force perpendicular to the central axis of the shock absorber), and the ball screw shaft and the ball screw nut are twisted to impair rotation of the ball screw mechanism. There is a risk that the interference sound will be generated, or dust generated due to the interference may bite into the ball screw mechanism and damage the ball screw mechanism.

  An object of the present invention is to suppress the deflection of a ball screw shaft due to a lateral force in an electromagnetic shock absorber.

  In the invention of claim 1, a ball screw shaft is screwed to a ball screw nut fixed to a damper case, a motor is coupled to the ball screw shaft, and linear motion of the ball screw nut is converted into rotational motion of the ball screw shaft, This rotational motion is transmitted to the motor shaft to generate an electromagnetic force in the motor, and the torque that resists the rotation of the motor shaft due to the electromagnetic force is used as a damping force that suppresses the linear motion of the ball screw nut. In the shock absorber, the end that protrudes into the damper case through the ball screw nut of the ball screw shaft is supported by a bearing, and the bearing holder that holds the bearing is supported by the damper case so as to be non-rotating and slidable. Is.

  According to a second aspect of the present invention, in the first aspect of the present invention, a guide shaft that is parallel to the ball screw shaft is fixed to the bearing holder, and the guide shaft is slidably supported in the vicinity of the ball screw nut fixing portion in the damper case. A guide bush is provided.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a slide bush that is slidably supported on the inner periphery of the damper case is provided on the outer periphery of the bearing holder.

(Claim 1)
(a) The ball screw shaft is supported by the ball screw nut fixed to the damper case, and the ball screw shaft end is fixed to the damper case and slidably supported by the bearing holder. Supported. Therefore, the intermediate portion and the lower end portion of the ball screw shaft are supported, so that the deflection of the ball screw shaft due to the lateral force can be suppressed.

  Since the ball screw shaft and the ball screw nut are not twisted, there is no interference sound between the ball screw shaft and the damper case, and no dust is generated due to the interference, the ball screw mechanism is not damaged.

(Claim 2)
(b) Since the guide shaft is fixed to the bearing holder, and this guide shaft is slidably supported by the guide bush provided at the ball screw nut fixing portion in the damper case, it can be opposed to the lateral force acting on the ball screw shaft.

(Claim 3)
(c) Since the slide bush provided on the outer periphery of the bearing holder is slidably supported on the inner periphery of the damper case, the slidability of the bearing holder with respect to the damper case can be improved.

  1 is an overall sectional view showing an electromagnetic shock absorber, FIG. 2 is a sectional view showing the upper half of FIG. 1, FIG. 3 is a sectional view showing the lower half of FIG. 1, and FIG. FIG. 5 shows the operation of the electromagnetic shock absorber, (A) is a cross-sectional view showing the compression stroke, (B) is a cross-sectional view showing the expansion stroke, and FIG. 6 is an enlarged cross-sectional view showing the stopper device. FIG. 7 is an enlarged sectional view of the bearing holder.

  As shown in FIGS. 1, 2, and 3, when the electromagnetic shock absorber 10 is used as a vehicle suspension, for example, a wheel-side mounting member 13 provided on a bottom cap 12 that constitutes the bottom surface of the cylindrical damper case 11 is provided. The vehicle body side attachment member 23 attached to the wheel side and attached to the base member 21 via the mount rubber 22 is attached to the vehicle body side.

  A ball screw nut 30 is fixed to the damper case 11. In this embodiment, the ball screw nut 30 is inserted into a nut case 31 fixedly fitted in the upper end opening of the damper case 11, and the mounting flange 30 </ b> A is bolted to the upper end boss portion of the nut case 31.

  A ball screw shaft 40 is screwed onto the ball screw nut 30. A ball loaded so as to be able to circulate is fitted into the spiral ball holding portion provided on the inner periphery of the ball screw nut 30 in the spiral thread groove of the ball screw shaft 40. The ball screw shaft 40 extends from the damper case 11 toward the center through hole 21 </ b> A of the base member 21, and includes a power transmission means 50 built in a gear housing 51 fixed to the upper part of the base member 21. To the motor 60. The power transmission means 50 and the motor 60 are disposed in the vehicle.

  In the electromagnetic shock absorber 10, the damper case 11 and the ball screw nut 30 are applied to the ball screw shaft 40 supported by the base member 21 and the gear housing 51 when subjected to the thrust or vibration from the road surface while the vehicle is running. On the other hand, it moves linearly in the up and down direction, and this linear movement is converted into a rotational motion of the ball screw shaft 40 by the combination of the ball screw nut 30 and the ball screw shaft 40, and this rotational motion is converted into a motor via the power transmission means 50. The electromagnetic force is generated in the motor 60 by being transmitted to the shaft 61.

  The motor 60 is connected to a control circuit (not shown) or the like, or the electrodes of the motor 60 are connected to form a closed circuit, and a torque that resists rotation of the motor shaft 61 due to electromagnetic force is generated. Thus, an electromagnetic force is generated in the motor 60.

  The torque that resists the rotation of the motor shaft 61 due to the electromagnetic force generated in the motor 60 suppresses the rotational movement of the ball screw shaft 40, and thus acts as a damping force that suppresses linear movement of the ball screw nut 30. In other words, it acts as a damping force that suppresses linear motion of the damper case 11 that expands and contracts vertically with respect to the base member 21.

  The motor 60 is used as an electromagnetic force generation source, and various motors such as a DC motor, an AC motor, and an induction motor can be employed.

  Hereinafter, (A) the structure of the power transmission means 50, (B) the steady-state structure of the ball screw shaft 40, and (C) the stopper structure at the stroke end will be described.

(A) Power transmission means 50
As shown in FIG. 4, the gear housing 51 of the power transmission means 50 rotatably supports a drive shaft 41 coupled to the upper end portion of the ball screw shaft 40 by a joint 42 by a bearing 43. The drive shaft 41 to which the ball screw shaft 40 is coupled is supported with respect to the bearing 43 so as to be movable in the vertical direction in the axial direction. At the upper end portion of the ball screw shaft 41, a collar-shaped clutch plate 71 constituting the clutch 70 is provided. Further, the power transmission means 50 is connected to the rotary shaft 60A of the motor 60 by the joint 62 with the above-mentioned motor shaft 61, and the motor shaft 61 is rotatably supported on the gear housing 51 by the upper and lower bearings 63 and 64, and the motor The driven gears 65A and 65B are fixedly provided on the upper and lower sides of the shaft 61.

  The power transmission means 50 enables the ball screw shaft 40 to be selectively coupled to either the first transmission system 50A corresponding to the compression stroke or the second transmission system 50B corresponding to the expansion stroke by the clutch 70. The first transmission system 50 </ b> A transmits the rotational motion in one direction of the ball screw shaft 40 corresponding to the linear motion in the compression direction of the ball screw nut 30 to the motor shaft 61, and the second transmission system 50 </ b> B The rotational motion in the opposite direction of the ball screw shaft 40 corresponding to the linear motion in the extending direction is transmitted to the motor shaft 61, and both the transmission systems 50A and 50B rotate the motor shaft 61 in the same direction. At this time, the clutch 70 enables the ball screw shaft 40 to be coupled to either the first transmission system 50A or the second transmission system 50B in accordance with the movement direction of the ball screw nut 30 and the ball screw shaft 40.

  Specifically, the first transmission system 50 </ b> A includes a gear train that includes a drive gear 52 </ b> A that can be brought into frictional contact with the clutch plate 71 of the clutch 70, and a driven gear 65 </ b> A that is fixed to the motor shaft 61. . The support shaft 53A of the drive gear 52A is rotatably supported on the gear housing 51 by a bearing 54A.

  The second transmission system 50B includes a drive gear 52B that can be brought into frictional contact with the clutch plate 71 of the clutch 70, a driven gear 65B that is fixed to the motor shaft 61, and a counter gear that is interposed between the two gears 52B and 65B. The gear train is composed of 55A and 55B. The support shaft 53B of the drive gear 52B is rotatably supported on the gear housing 51 by a bearing 54B. The support shaft 56 of the counter gears 55A and 55B is rotatably supported on the gear housing 51 by upper and lower bearings 57 and 58, and the counter gear 55A meshes with the drive gear 52B and the counter gear 55B meshes with the driven gear 65B.

  In the first transmission system 50A and the second transmission system 50B, the drive gears 52A and 52B, the counter gears 55A and 55B, and the driven gears 65A and 65B have the same number of teeth (the same diameter).

The clutch 70 is caused by the vertical movement displacement in the axial direction of the ball screw shaft 40 and the drive shaft 41 caused by any linear motion of the ball screw nut 30 to expand or contract.
(a) In the compression stroke, since the ball screw shaft 40 and the drive shaft 41 are pushed upward, as shown in FIG. 5A, the clutch plate 71 at the upper end of the drive shaft 41 is driven in the first transmission system 50A. The friction plate fa provided on the lower surface of the gear 52A is frictionally coupled, and the rotational motion in one direction of the ball screw shaft 40 is transmitted to the motor shaft 61 through the engagement of the drive gear 52A and the driven gear 65A. Rotate in one direction,
(b) In the extension stroke, the ball screw shaft 40 and the drive shaft 41 are pulled downward, so that the clutch plate 71 at the upper end of the drive shaft 41 is driven by the second transmission system 50B as shown in FIG. The motor shaft 61 is frictionally coupled to a friction plate fb provided on the upper surface of the gear 52B, and the rotational motion of the ball screw shaft 40 in the opposite direction is engaged with the drive gear 52B and the counter gear 55A, and the counter gear 55B and the driven gear 65B. The motor shaft 61 is rotated in the same direction as the above-described (a) by the intervention of the counter gears 55A and 55B.

  The power transmission means 50 is provided with a clutch transmission force adjuster 72 in the gear housing 51. The clutch transmission force adjuster 72 is screwed and provided coaxially above the drive gear 52A in the gear housing 51. When the adjuster 72 is pushed, the bearing 54A of the drive gear 52A is pushed by the bearing receiver 72A, and the friction plate fa of the drive gear 52A is pushed. The clutch plate 71 is pressed toward the clutch plate 71 so that a frictional contact pressure with the clutch plate 71 can be applied.

  The first transmission system 50 </ b> A and the second transmission system 50 </ b> B of the power transmission means 50 constitute a speed increaser that accelerates the rotation of the ball screw shaft 40 and transmits it to the motor shaft 61.

  In the electromagnetic shock absorber 10, an electromagnetic clutch is employed as the clutch 70, and the ball screw shaft 40 is moved to the first transmission system 50A and the second transmission system by an electromagnetic operation corresponding to the linear motion of the ball screw nut 30. It may be connectable to either one of 50B.

Therefore, the electromagnetic shock absorber 10 has the following effects.
(a) Even if there is a sudden change in the direction of the expansion / contraction stroke on the ball screw nut 30 side, the motor 60 always rotates in the same direction, and there is no need to reversely rotate. The ball screw shaft 40 can change the direction of rotation without being affected by the inertia force of the motor 60 without causing resistance to the direction change. Therefore, the responsiveness to sudden switching in the expansion / contraction stroke direction is improved, and the motor 60 and the power transmission means 50 can be protected.

  (b) Since the ball screw shaft 40 can be selectively coupled to either the first transmission system 50A or the second transmission system 50B by the clutch 70 and the counter gears 55A and 55B are provided in the second transmission system 50B, the motor 60 The rotation direction can be always made the same easily. Further, since the friction clutch 70 is used as the clutch 70, the clutch plate 71 slides in response to sudden switching in the expansion / contraction stroke direction, and the rotational force of the ball screw shaft 40 can be released.

  (c) Since the first transmission system 50A and the second transmission system 50B constitute a speed increasing device that accelerates and transmits the rotation of the ball screw shaft 40 to the motor shaft 61, the rotation angle of the ball screw shaft 40 is small. Even when the rotation angle of the motor 60 is increased, a large damping effect can be obtained, and the damping force can be easily controlled. A speed increasing ratio is set according to the output of the motor 60, and a small motor can also be adopted.

  (d) Since the switching operation of the clutch 70 is performed by the axial displacement of the ball screw shaft 40 caused by the linear motion of the ball screw nut 30, the switching means of the clutch 70 can be simplified.

  (e) When the switching operation of the clutch 70 is performed by an electromagnetic operation corresponding to the linear motion of the ball screw nut 30, the timing of coupling the motor 60 to the ball screw shaft 40 is freely controlled, and the finer operation is performed. Damping force control can be performed.

(B) Stabilizing structure of ball screw shaft 40 In the electromagnetic shock absorber 10, as shown in FIGS. 6 and 7, the ball screw shaft 40 protrudes into the damper case 11 through the ball screw nut 30. The end portion is rotatably supported by a bearing 80, and a bearing holder 81 that holds the bearing 80 is supported on the damper case 11 so as to be non-rotatable and slidable. A bearing retaining member 82 is screwed to the lower end of the bearing holder 81, and the bearing retaining member 82 seals the bearing holder 81 and holds the bearing 80.

  At this time, the upper ends of the two guide shafts 83 and 83 that are parallel to the ball screw shaft 40 are nut-fixed at two positions in the diameter direction that sandwich the ball screw shaft 40 at the lower end portion of the base member 21. The guide shaft 83 is a hole provided at the tip of the bearing holder 81 in a state of being slidably supported by the guide bush 32 provided at the upper end boss portion of the nut case 31 that fixes the ball screw nut 30 to the damper case 11. As a result, the bearing holder 81 is supported to prevent rotation with respect to the damper case 11. The guide shaft 83 reinforces the ball screw shaft 40 against a lateral force (an external force orthogonal to the central axis of the shock absorber 10) in the electromagnetic shock absorber 10 forming a strut damper or the like, and has a required strength. The thickness and number are determined according to the conditions.

  Further, the bearing holder 81 is fixedly provided with a slide bush 84 slidably supported on the inner periphery of the damper case 11 on the outer periphery, and as a result, the bearing holder 81 is slidably supported with respect to the damper case 11.

  A cylindrical dust cover 85 that covers the damper case 11, the ball screw shaft 40, and the guide shaft 83 is nut-fastened together with the guide shaft 83 at the lower end portion of the base member 21.

Therefore, the electromagnetic shock absorber 10 has the following effects.
(a) An intermediate portion of the ball screw shaft 40 is supported by a ball screw nut 30 fixed to the damper case 11, and an end portion of the ball screw shaft 40 is supported on the damper case 11 so as to be slidable. The bearing holder 81 was supported. Therefore, the intermediate portion and the lower end portion of the ball screw shaft 40 are supported, and the deflection of the ball screw shaft 40 due to lateral force can be suppressed.

  Since the ball screw shaft 40 and the ball screw nut 30 are not twisted, there is no interference sound between the ball screw shaft 40 and the damper case 11, and no dust is generated due to the interference, the ball screw mechanism is not damaged.

  (b) Since the guide shaft 83 is fixed to the bearing holder 81 and this guide shaft 83 is slidably supported by the guide bush 32 provided on the nut case 31 in the damper case 11, it opposes the lateral force acting on the ball screw shaft 40. it can.

  (c) Since the slide bush 84 provided on the outer periphery of the bearing holder 81 is slidably supported on the inner periphery of the damper case 11, the slidability of the bearing holder 81 with respect to the damper case 11 can be improved.

(C) Stopper structure at the stroke end A bump rubber 91 is fixedly provided on the bottom surface of the damper case 11, and the lower surface of the bearing retaining member 82 constituting the lower end surface of the bearing holder 81 facing the bump rubber 91 is used as a bump receiving surface 91A. . The bump rubber 91 has a hollow shape, and the base end hollow portion of the bump rubber 91 is press-fitted and fixed to the center protrusion 12A provided on the bottom cap 12 of the damper case 11.

  An annular rebound rubber 92 is fixedly provided on the upper end surface of the bearing holder 81, and the lower surface of the nut case 31 constituting the bottom surface of the ball screw nut 30 opposite thereto is used as a rebound receiving surface 92A. The outer periphery of the annular rebound rubber 92 is fitted into an annular recess formed around the ball screw shaft 40 on the upper end surface of the bearing holder 81. Between the inner periphery of the rebound rubber 92 and the ball screw shaft 40, an annular clearance larger than the radial thickness of the rebound rubber 92 is provided in the free state of the rebound rubber 92, and the rebound rubber 92 compressed by the rebound receiving surface 92A. Is prevented from interfering with the ball screw shaft 40.

Therefore, the electromagnetic shock absorber 10 has the following effects.
(a) The bump rubber 91 is provided on the bottom surface of the damper case 11, and the bump receiving surface 91 </ b> A is provided on the lower end surface of the bearing holder 81. Since the bump rubber 91 is not provided around the ball screw shaft 40, the bump rubber 91 compressed on the compression stroke side does not interfere with the ball screw shaft 40 and absorbs the restriction at the stroke end and the impact at the stroke end. . The bump rubber 91 does not come into contact with the ball screw shaft 40 and is not damaged, and the rotational movement of the ball screw shaft 40 is not hindered.

  (b) Since the end surface of the bearing holder 81 provided with the bump receiving surface 91A is constituted by the bearing retaining member 82 attached to the bearing holder 81, the bump retaining surface 91A is provided on the bearing retaining member 82 which is a non-rotating member. Will be provided. Therefore, the bump rubber 91 is only compressed and deformed at the end of the compression stroke with the bump receiving surface 91 </ b> A, and is not torsionally deformed. The bump rubber 91 is not damaged and the rotation of the ball screw shaft 40 is not hindered.

  (c) A rebound rubber 92 is provided on the upper end surface of the bearing holder 81, and a rebound receiving surface 92A is provided on the bottom surface of the ball screw nut 30. The rebound rubber 92 compressed at the extension stroke end absorbs the restriction at the stroke end and the impact at the stroke end.

  (d) The bottom surface of the ball screw nut 30 provided with the rebound receiving surface 92 </ b> A is constituted by a nut case 31 in which the ball screw nut 30 is accommodated.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention. For example, in the electromagnetic shock absorber of the present invention, it is not necessary to intervene the power transmission means of the speed increasing mechanism between the ball screw shaft and the motor shaft.

FIG. 1 is an overall sectional view showing an electromagnetic shock absorber. 2 is a cross-sectional view showing the upper half of FIG. FIG. 3 is a cross-sectional view showing the lower half of FIG. FIG. 4 is an enlarged sectional view showing the power transmission means. FIG. 5 shows the operation of the electromagnetic shock absorber, (A) is a cross-sectional view showing a compression stroke, and (B) is a cross-sectional view showing an expansion stroke. FIG. 6 is an enlarged cross-sectional view of the stopper device. FIG. 7 is an enlarged sectional view of the bearing holder.

Explanation of symbols

10 Electromagnetic shock absorber 11 Damper case 30 Ball screw nut 31 Nut case (ball screw nut fixing part)
32 Guide bush 40 Ball screw shaft 60 Motor 61 Motor shaft 80 Bearing 81 Bearing holder 83 Guide shaft 84 Slide bush

Claims (3)

The ball screw shaft is screwed onto the ball screw nut fixed to the damper case, the motor is connected to the ball screw shaft, the linear motion of the ball screw nut is converted into the rotational motion of the ball screw shaft, and this rotational motion is converted into the motor shaft. In an electromagnetic shock absorber that transmits and generates an electromagnetic force in the motor, and uses a torque that resists the rotation of the motor shaft due to the electromagnetic force as a damping force that suppresses the linear motion of the ball screw nut.
The end that protrudes into the damper case through the ball screw nut of the ball screw shaft is supported by a bearing, and the bearing holder that holds the bearing is supported by the damper case so as to be non-rotatable and slidable. Electromagnetic shock absorber.   The electromagnetic buffer according to claim 1, wherein a guide bush that is parallel to the ball screw shaft is fixed to the bearing holder, and a guide bush that slides and supports the guide shaft is provided in the vicinity of the ball screw nut fixing portion of the damper case. vessel.   The electromagnetic shock absorber according to claim 1 or 2, wherein a slide bush is provided on the outer periphery of the bearing holder so as to be slidably supported on the inner periphery of the damper case.

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