JP2006177477A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber for improving ride comfort on a vehicle. <P>SOLUTION: The shock absorber comprises: a first cylinder 2; a second cylinder 5 inserted into the first cylinder 2; a motion converting mechanism H mounted between the first cylinder 2 and the second cylinder 5 for converting relative motion between the first cylinder 2 and the second cylinder 5 into rotating motion; and a motor 1 fixed to either one of the first cylinder 2 or the second cylinder 5 to which the rotating motion is transmitted. It controls relative movement between the first cylinder 2 and the second cylinder 5 with the output torque of the motor 1. A dust cover D is provided for covering the first cylinder 2 at its outer periphery side and the second cylinder 5 at its outer periphery side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a shock absorber that controls expansion and contraction with torque output from a motor.

  This type of shock absorber includes a ball screw mechanism that is interposed between the outer cylinder and the inner cylinder and converts the linear relative motion between the outer cylinder and the inner cylinder into a rotational movement, and is fixed in the outer cylinder and transmits the rotational movement. The conventional shock absorber uses the rotational torque generated by the motor as a damping force that suppresses relative movement between the outer cylinder and the inner cylinder. .

In addition, in this conventional shock absorber, when water, dust, or the like enters the space formed by the outer cylinder and the inner cylinder, the motor or ball screw mechanism, which is an electrical device as a damping force generation source, is deteriorated. Since there is a risk of damage, a dust seal is provided between the outer cylinder and the inner cylinder to avoid the above problems.
Japanese Unexamined Patent Application Publication No. 2004-11750 (Embodiment of the Invention, FIG. 1)

  In the conventional shock absorber described above, the damping force is generated by the torque of the motor. Therefore, the damping force can be adjusted by controlling the amount of current flowing through the winding of the motor, and the actuator can be supplied by actively supplying the current. However, there is a possibility that it is pointed out that the following problems are caused, although it is very useful in that an active suspension can be realized with one shock absorber.

  That is, as described above, in the conventional shock absorber, a dust seal is provided between the outer cylinder and the inner cylinder in order to prevent deterioration of the motor and the ball screw mechanism, but this dust seal is in sliding contact with the outer peripheral surface of the inner cylinder. Therefore, sliding resistance occurs when the outer cylinder and the inner cylinder move relative to each other.

  When the shock absorber expands and contracts, the above-mentioned sliding resistance is always generated, so the relative movement between the outer cylinder and the inner cylinder becomes awkward, and the smooth expansion and contraction of the shock absorber is hindered, and the expansion and contraction control is also performed. In particular, when the outer cylinder and the inner cylinder start to move relative to each other, the expansion / contraction operation of the shock absorber becomes awkward.

  Then, there is a possibility that smooth expansion and contraction may not be realized with the conventional shock absorber. As a result, when this shock absorber is applied to a vehicle, the ride comfort in the vehicle may be deteriorated.

  Accordingly, the present invention has been developed to improve the above-described problems, and an object of the present invention is to provide a shock absorber that can improve the riding comfort in a vehicle.

  In order to achieve the above-described object, the present invention provides a first cylinder, a second cylinder inserted into the first cylinder, and a first cylinder and a second cylinder interposed between the first cylinder and the second cylinder. A motor conversion mechanism that converts relative motion between the first cylinder and the second cylinder into a rotary movement; and a motor that is fixed to one of the first cylinder and the second cylinder and that transmits the rotary movement. In the shock absorber that controls the relative movement of the first cylinder and the second cylinder with the output torque of the first cylinder, a dust cover that covers the outer peripheral side of the first cylinder and the outer peripheral side of the second cylinder is provided. To do.

  According to the present invention, the dust cover prevents entry of rainwater, dust, or the like in the space formed by the first cylinder and the second cylinder, so that it is not necessary to provide a dust seal.

  Therefore, there is no problem due to the provision of the dust seal, that is, there is no sliding resistance due to the dust seal when the shock absorber is expanded and contracted, so the movement between the outer cylinder and the inner cylinder is smooth, and the shock absorber is smoothly expanded and contracted. Operation is guaranteed.

  Therefore, even if this shock absorber is applied to a vehicle, the ride comfort in the vehicle can be improved, and the expansion and contraction of the shock absorber becomes smooth, and the expansion and contraction control thereof becomes easy.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a diagram conceptually illustrating a shock absorber according to an embodiment.

  As shown in FIG. 1, the shock absorber in the present embodiment includes an outer cylinder 2 as a first cylinder, an inner cylinder 5 as a first cylinder that is slidably inserted into the outer cylinder 2, and an outer cylinder. 2, a ball screw nut 4 provided in the ball screw nut 4, a screw shaft 3 that is rotatably engaged with the ball screw nut 4, and a motor 1 that is fixed to the upper end of the inner cylinder 5 and connected to the screw shaft 3. When the shock absorber expands and contracts, that is, when the outer cylinder 2 as the first cylinder and the inner cylinder 5 as the second cylinder move relative to each other, the linear movement of the ball screw nut 4 is changed to the rotational movement of the screw shaft 3. And the rotational motion is transmitted to the shaft 10 of the motor 1 to generate an electromagnetic force in the motor 1, and the torque that resists the rotation of the shaft 10 due to the electromagnetic force is applied to the rotational motion of the screw shaft 3. It is used as a damping force to suppress the linear motion of the ball screw nut 4 by suppressing It is intended that can be inhibited relative axial movement of the inner cylinder 5 and outer cylinder 2.

  In the case of the present embodiment, the shock absorber is connected to the axle side member of the vehicle via the eye E provided at the lower end in FIG. It is connected to the vehicle body side member via the mount 20, and as a result, relative movement between the axle side member and the vehicle body side member can be suppressed.

 Hereinafter, the detailed structure of each part will be described. The motor 1 is mounted and connected in a mount inner cylinder 21 of a mount 20 connected to the upper end in FIG. 1 of the inner cylinder 5, and the shaft 10 of the motor 1 is in ball bearings 8 and 9 in the inner cylinder 5. Is connected to a screw shaft 3 that is rotatably inserted through the shaft. Note that the shaft 10 of the motor 1 and the screw shaft 3 may be integrally formed.

 Further, as described above, the mount 20 for attaching the shock absorber to the vehicle is provided at the upper end in FIG. 1 of the inner cylinder 5. The mount 20 includes a mount inner cylinder 21 and a mount outer cylinder. 22 and an anti-vibration rubber 23 that connects the mount inner cylinder 21 and the mount outer cylinder 22. The mount outer cylinder 22 is connected to the vehicle body side, and the shock absorber is connected to the vehicle body side member.

 On the other hand, as shown in FIG. 1, the motor 1 includes a case 30, the shaft 10, a magnet 32 attached to the outer periphery of the shaft 10 via a cylindrical yoke 31, and the inner periphery of the case 30. A core 33 that is an armature core attached so as to face the magnet 32 and a winding 34 fitted to the core 33 are provided, and is configured as a so-called brushless motor.

 The magnet 32 is formed in an annular shape and has a divided magnetic pole pattern in which the N pole and the S pole appear alternately along the circumference, but the plurality of magnets are bonded to form an annular shape. It may be formed.

 The motor 1 is connected to an external power source so as to be able to control the rotational torque of the shaft 10 and is adjusted to obtain a desired damping force. By driving, this shock absorber functions not only as a shock absorber but also as an actuator.

 Incidentally, the motor 1 is provided with a rotor position detecting means 40, and an outer cylinder 2 and an inner cylinder 5 in which a shock absorber is generated according to the state of rotation of the rotor (rotation angle, angular velocity, etc.), As a result, the relative movement between the vehicle body side member and the axle side member can be controlled. Specifically, for example, a Hall element, a magnetic sensor, or an optical sensor may be used as the position detection unit 40.

 In the present embodiment, the motor 1 is a brushless motor, but various motors such as a DC motor, an AC motor, an induction motor, and the like can be used as long as they can be used as an electromagnetic force generation source.

 Next, the screw shaft 3 connected to the shaft 10 is provided with a screw groove on the outer periphery thereof, and is a ball that is non-rotatably provided at the upper end portion in FIG. 1 of the connecting tube 6 rising from the bottom of the outer tube 2 described above. The screw nut 4 is rotatably screwed.

  That is, in the case of this embodiment, the motion conversion mechanism H is constituted by the screw shaft 3 and the ball screw nut 4, and when the ball screw nut 4 performs a linear motion in the vertical direction in FIG. Since the rotation of the ball screw nut 4 is restricted by the outer cylinder 2 fixed to the axle side, the screw shaft 3 is forcibly rotated, and conversely, the motor 1 is driven to rotate the screw shaft 3. Then, since the rotation of the ball screw nut 4 is restricted, it is possible to move the ball screw nut 4 in the vertical direction.

 In addition, bearings 11 and 12 are provided between the outer cylinder 2 and the inner cylinder 5 to prevent the inner cylinder 5 from being shaken with respect to the outer cylinder 2, and the lower ends of the connecting cylinder 6 and the inner cylinder 5 in FIG. Is provided with a bearing 15 between which the axial displacement of the connecting cylinder 6 and the inner cylinder 5 is prevented. As a result, the axial displacement of the screw shaft 3 with respect to the ball screw nut 4 is prevented, Thereby, it is possible to prevent a load from being concentrated on a part of the balls (not shown) of the ball screw nut 4 and to prevent the ball or the screw groove of the screw shaft 3 from being damaged.

 In addition, since the ball or the screw groove of the screw shaft 3 can be prevented from being damaged, the smooth movement of each of the rotation of the screw shaft 3 with respect to the ball screw nut 4 and the movement of the shock absorber in the expansion / contraction direction can be maintained. Since the smoothness of each operation can be maintained, the function as a shock absorber is not impaired, and the failure of the shock absorber can be prevented.

  Further, a dust cover D is provided to cover the outer cylinder 2 from the outer periphery in the vicinity of the upper end in FIG. 1 to the outer periphery in the vicinity of the upper end of the inner cylinder 5, and the dust cover D holds the outer cylinder that holds the outer periphery of the outer cylinder 2. Part 25, an inner cylinder holding part 26 for holding the outer periphery of the inner cylinder 5, and a bellows part 27 connected to the upper end of the outer cylinder holding part 25 and the lower end of the inner cylinder holding part 26. The dust cover D isolates the space R formed by the outer cylinder 2 and the inner cylinder 5 from the outside of the shock absorber, so that intrusion of rainwater, dust or the like into the space R is prevented.

 The connecting cylinder 6 is not necessarily formed in a cylindrical shape, and may be any one that can connect the ball screw nut 4 to the outer cylinder 2 in a state where the rotation of the ball screw nut 4 is restricted.

  Further, the bearing 15 may be omitted, and even in this case, the shaft runout of the screw shaft 3 with respect to the ball screw nut 4 is prevented by the bearings 11 and 12 described above, so there is no problem.

  In the present embodiment, the motion conversion mechanism H is constituted by a ball screw nut and a screw shaft. However, this may be constituted by another configuration, for example, a rack and pinion, or a ball screw. The nut may be replaced with a simple nut.

  Now, the shock absorber of the present invention is configured as described above, and the operation thereof will be described below.

  First, when the shock absorber expands and contracts, that is, when the inner cylinder 5 moves up and down in FIG. 1 with respect to the outer cylinder 2, the linear motion of the ball screw nut 4 connected to the outer cylinder 2 is The ball screw mechanism of the screw nut 4 and the screw shaft 3 is converted into a rotational motion of the screw shaft 3, and the shaft 10 of the motor 1 connected to the screw shaft 3 also rotates.

  When the shaft 10 of the motor 1 exhibits a rotational motion, the winding 34 in the motor 1 crosses the magnetic field of the magnet 32, and an induced electromotive force is generated. The shaft 10 of the motor 1 is electromagnetically caused by the induced electromotive force. Torque due to force acts, and the torque suppresses the rotational movement of the shaft 10.

  The effect of suppressing the rotational movement of the shaft 10 is to suppress the rotational movement of the screw shaft 3, and the rotational movement of the screw shaft 3 is suppressed, so that the linear movement of the ball screw nut 4 is suppressed. The shock absorber generates a damping force by the electromagnetic force and absorbs and relaxes vibration energy.

  At this time, when a current is actively supplied to the winding 34, the expansion and contraction of the shock absorber can be freely controlled by adjusting the torque acting on the shaft 10, that is, within a range in which the control force of the shock absorber can be generated. Since it is possible to control freely, it is possible to make the damping characteristic of the shock absorber variable or to make the shock absorber function as an actuator.

  In this shock absorber, as described above, intrusion of rainwater, dust, etc. in the space R formed by the outer cylinder 2 and the inner cylinder 5 is prevented by the dust cover D, so a dust seal is provided. I don't need it.

  Therefore, there is no problem due to the provision of the dust seal, that is, no sliding resistance is generated by the dust seal when the shock absorber is expanded and contracted, so that the movement between the outer cylinder and the inner cylinder is smooth, and the shock absorber is smoothly expanded and contracted. Operation is guaranteed.

  Therefore, even if this shock absorber is applied to a vehicle, the ride comfort in the vehicle can be improved, and the expansion and contraction of the shock absorber becomes smooth, and the expansion and contraction control thereof becomes easy.

  In each of the above-described embodiments, the motor 1 is fixed to the inner cylinder 5 side as the second cylinder, but the motor 1 connected to the screw shaft 3 is fixed to the outer cylinder 2 side as the first cylinder. The ball screw nut 4 may be provided on the inner cylinder 5 side.

  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 figure which shows notionally the buffer in one Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor 2 1st cylinder outer cylinder 3 Screw shaft 4 Ball screw nut 5 2nd cylinder inner cylinder 6 Connecting cylinder 8, 9 Ball bearing 10 Shaft 11, 12, 15 Bearing 20 Mount 21 Mount inner cylinder 22 Outside mount Tube 23 Anti-vibration rubber 25 Outer tube holding portion 26 Inner tube holding portion 27 Bellows portion 30 Case 31 Yoke 32 Magnet 33 Core 34 Winding 40 Position detecting means D Dust cover E Eye H Motion conversion mechanism

Claims (1)

A first cylinder, a second cylinder inserted into the first cylinder, and a relative movement between the first cylinder and the second cylinder interposed between the first cylinder and the second cylinder; A movement converting mechanism for converting to a rotary movement; and a motor that is fixed to one of the first cylinder and the second cylinder and that transmits the rotary movement. The first cylinder and the second cylinder are output torque of the motor. In the shock absorber for controlling the relative movement of the first shock absorber, a dust cover is provided to cover the outer peripheral side of the first tube and the outer peripheral side of the second tube.

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