JP2007225021A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the worsening of performance of a shock absorber using electromagnetic force as damping force. <P>SOLUTION: The shock absorber D1 whose expansion is damped with electromagnetic force on a winding opposed to a magnet comprises a suppressing means Y1 for suppressing the expansion. By converting or adding the damping force generated by the suppressing means Y1 into or to damping force, the temperature rise of the winding is suppressed to prevent the thermal demagnetization of the magnet, thus preventing the worsening of performance of the shock absorber. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improved shock absorber.

  In general, a shock absorber is interposed between two members that perform relative motion, and suppresses the relative motion of the members with a damping force.

  In particular, in the case of using the electromagnetic force acting on the winding facing the magnet as the generation source of the damping force, for example, a cylinder, a rod inserted into the cylinder, and a cylinder A plurality of windings attached along the axial direction and a plurality of magnets attached so that magnetic poles appear alternately on the outer peripheral side of the rod, and suppressing expansion and contraction by the force output by a so-called linear motor (for example, And a ball screw mechanism composed of a screw shaft and a ball screw nut, the relative motion between the vehicle body and the axle of the vehicle can be converted into a rotational motion, and the screw shaft is used as the output shaft of the motor. It is known that the ball screw nut is restrained in the vertical movement by the torque output from the motor (for example, see Patent Document 2).

In this type of shock absorber, not only a damping force is exhibited during expansion / contraction, but also a function as an actuator can be exhibited by supplying a current to the winding.
JP 2002-227927 A (Embodiment of the Invention, FIG. 1 and FIG. 2) Japanese Patent Laid-Open No. 08-197931 (paragraph number 0023, FIG. 1)

  By the way, in the conventional shock absorber as described above, when applied to a vehicle or the like, when performing vehicle body posture control or maintaining the vehicle height at a certain height, etc. It is necessary to supply a current to the wire so that the force is always exerted in the direction of expansion or contraction.

  However, in such a state, current supply is continued to be supplied to the windings, but the buffer itself does not expand or contract, or the expansion and contraction speed becomes extremely low, so the conversion efficiency of electrical energy into kinetic energy deteriorates. Most of the electrical energy is converted into heat.

  Then, under the above situation, the temperature rise of the winding becomes remarkable, and in the worst case, the magnet causes irreversible demagnetization, or the malfunction of the winding occurs due to burning of the winding, and the motor performance deteriorates. Eventually, the performance of the shock absorber may deteriorate.

  Accordingly, the present invention has been made to solve the above-described problems, and its object is to prevent performance deterioration of a shock absorber that uses an electromagnetic force as a damping force.

  In order to achieve the above-described object, the problem-solving means of the present invention is characterized in that a suppressor for suppressing expansion and contraction is provided in a shock absorber that attenuates expansion and contraction by electromagnetic force acting on a winding facing a magnet. .

  According to the present invention, expansion and contraction of the shock absorber can be suppressed by the suppression means in addition to the damping force by the electromagnetic force acting on the winding facing the magnet.

  Therefore, when controlling the attitude of the vehicle body with a shock absorber or maintaining the vehicle height at a constant height, that is, when the shock absorber functions as an actuator by actively energizing the windings, It is not necessary to perform posture control and vehicle height maintenance only with force, and it is possible to use a restraining means in combination.

  As a result, the amount of current to be supplied to the windings can be reduced, and as a result, the heating of the windings can be suppressed, the burning of the windings can be prevented, and the irreversible demagnetization of the magnets can be prevented. Thus, the performance of the shock absorber can be maintained.

  Hereinafter, the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a shock absorber according to the first embodiment. FIG. 2 is a longitudinal sectional view of the shock absorber according to the second embodiment. FIG. 3 is a longitudinal sectional view of the shock absorber according to the third embodiment.

  As shown in FIG. 1, the shock absorber D <b> 1 in the first embodiment includes a motion conversion mechanism H that converts a telescopic motion into a rotational motion, a motor M that transmits the rotational motion, and a suppression unit that suppresses the expansion and contraction. In this embodiment, the motion conversion mechanism H is a ball screw mechanism that includes a screw shaft 3 and a ball screw nut 4 that is rotatably attached to the screw shaft 3. Yes.

  When the shock absorber D1 expands and contracts, the motion converting mechanism H converts the vertical motion of the ball screw nut 4 into the rotational motion of the screw shaft 3, and the rotational motion is transmitted to the shaft 10 of the motor M. .

  At this time, an electromagnetic force is generated in the motor M to generate a torque that suppresses the rotation of the shaft 10, and this torque is used as a damping force that suppresses the linear motion of the ball screw nut 4 to extend and contract the shock absorber D <b> 1. It can be suppressed.

  Further, in the case of the present embodiment, this shock absorber D1 is connected to the axle side member of the vehicle via an eye 12 provided at the lower end in FIG. 1 of the outer cylinder 2 that holds the ball screw nut 4 on its inner peripheral side. On the other hand, the motor M can be connected to the vehicle body side member via a mount or the like (not shown), and the shock absorber D1 can be interposed between the axle side member and the vehicle body side member. is there.

 Further, as shown in FIG. 1, the motor M is attached so as to face the case 11, the shaft 10, a magnet (not shown) attached to the outer periphery of the shaft 10, and the inner periphery of the case 11. The coil is configured as a so-called brushless motor.

 The magnet 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 is formed so as to be annular by bonding a plurality of magnets. May be.

 The motor M is connected to an external power source and a control device (not shown) so that the rotational torque of the shaft 10 can be controlled. The motor M is adjusted to obtain a desired damping force, and the motor M is positively activated. By driving, the buffer D1 functions not only as a buffer but also as an actuator.

 Incidentally, the motor M is provided with a rotor position detection means so that the damping force generated by the shock absorber can be controlled in accordance with the state of rotation of the rotor (rotation angle, angular velocity, etc.). . Specifically, for example, a Hall element, a magnetic sensor, an optical sensor, or the like may be used as the position detection means.

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

 Further, a screw shaft 3 is connected to the lower end of the shaft 10, and the screw shaft 3 is provided with a screw groove on the outer periphery thereof, and is freely rotatable in the ball screw nut 4 held by the outer cylinder 2. Are screwed together. Note that the shaft 10 of the motor M and the screw shaft 3 may be integrally formed.

 A disc-shaped friction plate 14 is attached to the upper side of the lower end of the shaft 10.

 Friction members 15 and 15 having a curved surface similar to the outer peripheral surface of the friction plate 14 are opposed to the friction plate 14, and the friction members 15 and 15 are moved to the friction plate 14 by a moving means (not shown). It can be brought into contact with or separated from.

 As the moving means, an electromagnetic clutch, an electromagnetic brake, or the like can be used. Although not shown in detail, specifically, for example, a spring, an electromagnet, and a magnetic body provided on the friction member 15 are provided. The friction member 15 is urged toward the friction plate 14 to bring the friction member 15 into contact with the friction plate 14 when the electromagnet is not energized. It is possible to adjust the pressing force at the time of separation from the plate 14 and contact between the friction member 15 and the friction plate 14.

 In addition to the above, a means using a hydraulic pressure as used in a vehicle brake may be adopted. In any case, in this embodiment, the moving means is a control device (not shown). Is set so that the friction members 15, 15 can be brought into contact with the friction plate 14 with a predetermined force.

 In this case, the suppression means Y1 includes a friction plate 14 attached to the shaft 10, a friction member 15, and a moving means (not shown). The friction members 15 and 15 are brought into contact with the friction plate 14 with an appropriate pressing force. Thus, it is possible to generate a frictional force between the friction members 15 and 15 and the friction plate 14 and to suppress the rotation of the shaft 10 with this frictional force. The frictional force can be generated so as to be sandwiched, and the frictional force can be changed by changing the pressing force.

  On the other hand, the motion conversion mechanism H is composed of the screw shaft 3 and the ball screw nut 4 as described above. When the ball screw nut 4 moves linearly in the vertical direction in FIG. 4, since the rotational movement is restricted by the outer cylinder 2 fixed to the axle side, the screw shaft 3 is forcibly driven to rotate. Conversely, when the motor M is driven to rotate the screw shaft 3, 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 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, the ball screw nut 4 connected to the outer cylinder 2 moves up and down by the ball screw mechanism of the ball screw nut 4 and the screw shaft 3 to rotate the screw shaft 3. The shaft 10 of the motor M that is converted into motion and connected to the screw shaft 3 also rotates.

  When the shaft 10 of the motor M exhibits a rotational motion, an induced electromotive force is generated in the winding in the motor M due to the movement of the magnet, that is, the kinetic energy is regenerated to become electric energy, and is induced in the shaft 10 of the motor M. Torque due to electromagnetic force caused by the electromotive 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 the current is actively supplied to the windings, the expansion and contraction of the shock absorber can be freely controlled by adjusting the torque acting on the shaft 10, that is, within the range where the generation 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 addition, in the shock absorber D1, in addition to the torque output from the motor M, the frictional force generated by the restraining means Y1, that is, the frictional force generated when the friction members 15 and 15 are brought into contact with the friction plate 14 is used. The rotation of the shaft 10 can be suppressed.

  Therefore, when the vehicle body posture is controlled by the shock absorber D1 or when the vehicle height is maintained at a constant height, that is, the shock absorber D1 can be used as an actuator by actively energizing the windings of the motor M. When functioning, it is not necessary to perform posture control and vehicle height maintenance only with the torque output by the motor M, and the suppression means Y1 can be used in combination.

  Then, the amount of current to be supplied to the winding in the motor M can be reduced. As a result, the heat generation of the winding can be suppressed, the winding can be prevented from being burned, and the magnet is irreversible. Demagnetization can be prevented, and the performance of the shock absorber can be maintained.

  In order to maintain the vehicle height when the vehicle is stopped, the vehicle height can be maintained only by the frictional force generated by the restraining means Y1 without using the motor M, further reducing power consumption and preventing the temperature of the motor M from rising. it can.

  In addition, by controlling the magnitude of the frictional force generated by the suppression means Y1, it is possible to additionally apply a deficient damping force when the damping force is insufficient with only the torque of the motor M. Thus, the variable range of the generated damping force is widened, which is advantageous in controlling the attitude of the vehicle.

  Further, by detecting the temperature in the motor M, the damping force of the shock absorber D1 is generated only by the suppression means Y1 before reaching a temperature at which the windings are burned or the magnet is irreversibly demagnetized. It is also possible to switch, and in this case, it is possible to reliably prevent the winding from burning and the magnet from being thermally demagnetized.

  Since the damping force can be generated only by the suppression means Y1, even in the case of a failure in which the motor M is abnormal and the damping force cannot be generated by the motor M, in that case, the suppression means Y1 Since the damping force may be generated, it is avoided that the damping force cannot be exhibited.

  Furthermore, the suppression means Y1 can prevent the ball screw nut 4 from colliding with the friction plate 14 and the screw shaft 3 from colliding with the bottom of the outer cylinder 2 when the shock absorber D1 is most compressed or extended. Further, since the impact at the time of collision is not transmitted to the vehicle body, the ride comfort in the vehicle can be improved.

  It continues and demonstrates the buffer D2 in 2nd Embodiment. In addition, about the member similar to 1st Embodiment, only the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.

  In the shock absorber D2 in the second embodiment, as shown in FIG. 2, instead of the friction plate 14 of the restraining means Y1 on the shaft 10 of the motor M of the shock absorber D1 in the first embodiment, the drive gear 16, and the driven gear 17 is engaged with the driven gear 17. A disk 19 having a friction plate 18 at the upper end is connected to the driven gear 17, and the friction member 20 is opposed to the friction plate 18. I'm allowed.

  The friction member 20 can also be brought into contact with or separated from the friction plate 18 by a moving means (not shown), similarly to the friction member 15 in the first embodiment.

 As the moving means, similar to the moving means of the first embodiment, a configuration similar to that of an electromagnetic clutch, an electromagnetic brake, or the like may be adopted, and the force for pressing the friction member 20 against the friction plate 18 is sufficient. Can be adjusted.

 The number of teeth of the drive gear 16 is set to be larger than the number of teeth of the driven gear 17, and the rotational speed of the shaft 10 can be increased by the gear mechanism of the drive gear 16 and the driven gear 17. As described above, the speed increasing means is composed of the gear mechanism of the drive gear 16 and the driven gear 17.

 In the second embodiment, the suppression means Y2 is composed of the speed increasing means, the disc 19, the friction plate 18, the friction member 20, and the moving means (not shown) attached to the driven gear 17. In this case as well, the friction members 20 and 20 are brought into contact with the friction plate 18 with a predetermined force, thereby generating a friction force between the friction members 20 and 20 and the friction plate 18. 10 rotations can be suppressed.

  As is apparent from the above, even in the shock absorber D2, similarly to the shock absorber D1 in the first embodiment, the temperature rise of the winding of the motor M, and hence the thermal demagnetization of the magnet can be prevented. The function of the vessel can be maintained.

  In addition, in the shock absorber D2 in the second embodiment, in addition to the function and effect of the shock absorber D1 in the first embodiment, the restraining means Y2 includes a speed increasing means. The damping force that suppresses expansion and contraction by the frictional force generated by the means Y2 is amplified.

  Therefore, a sufficient damping force can be obtained even if the frictional force generated by the restraining means Y2 is small, and the moving means of the restraining means Y2 is such that the friction member 20 and the friction plate 18 abut particularly when the electromagnet is energized. In the case of adopting a simple configuration, it is possible to reduce the amount of power supplied to the electromagnet, so that power is saved.

  Further, since the damping force due to the frictional force can be amplified, the variable range of the generated damping force is further widened, which is advantageous in controlling the posture of the vehicle.

  Finally, the shock absorber D3 in the third embodiment will be described. As shown in FIG. 3, the shock absorber D3 includes a cylinder 30, a rod 31 movably inserted into the cylinder 30, a plurality of windings 32 provided in the cylinder 30 along the axial direction, and a rod. A plurality of magnets 33 provided on the outer periphery of 31 along the axial direction, and a suppression means Y3 that suppresses relative movement between the cylinder 30 and the rod 31, that is, expansion and contraction of the shock absorber D3.

  Hereinafter, the cylinder 30 is formed of a magnetic material, and the plurality of windings 32 are attached to the inner periphery of the cylinder 30 along the axial direction as described above. The winding 32 is formed by being wound around a core (not shown).

  On the other hand, the rod 31 is also made of a magnetic material, and when the rod 31 moves relative to the cylinder 30, the magnet 33 moves relative to the winding 32, so that an induced electromotive force is generated in the winding 32 and the magnet 33. Electromagnetic force acts to prevent the movement of.

  Further, when the coil 32 is positively energized, an electromagnetic force can be generated so as to move the magnet 33 up and down in FIG. 3, and in this case as well, the shock absorber D3 is the same as the shock absorbers D1 and D2. Can also function as an actuator.

  That is, a so-called linear motor is formed by the winding 32 provided on the inner periphery of the cylinder 30 and the magnet 33 provided on the outer periphery of the rod 31.

  Although not shown, an inner cylinder formed of a non-magnetic material is provided on the inner peripheral side of the winding 32, and an annular bearing that is in sliding contact with the inner cylinder is provided on the outer periphery of the upper end of the rod 31. It is desirable to provide an annular bearing that is in sliding contact with the outer periphery of the rod 31 at the lower end thereof to prevent axial displacement between the cylinder 30 and the rod 31 and to protect the winding 32 with the inner cylinder.

  Further, friction members 35 and 35 are provided at the lower end of the cylinder 30, and the friction members 35 and 35 are provided with a curved surface similar to the outer peripheral surface of the rod 31, which is the same as in the first embodiment. The same moving means (not shown) can be brought into and out of contact with the rod 31 from both sides of the rod 31, respectively.

  Therefore, this suppression means Y3 can generate a frictional force by sandwiching both sides of the rod 31 with the friction members 35, 35 on the outer peripheral surface of the rod 31.

  Even in the shock absorber D3, a damping force is generated on the linear motor side, and in addition to this, the movement of the rod 31 with respect to the cylinder 30, that is, the expansion and contraction of the shock absorber D3 is caused by the frictional force generated by the suppressing means Y3. The damping force due to this frictional force can be added to the damping force generated on the linear motor side.

  Therefore, it is possible to achieve the same effects as those of the first embodiment, and it is possible to suppress the temperature rise of the winding 32 and, consequently, the temperature rise of the magnet 33, so that the winding 32 is burned out and the magnet 33 is thermally demagnetized. This prevents the shock absorber performance from being maintained.

  In the first and second embodiments described above, the screw shaft 3 and the motor M are connected. However, when the ball screw nut 4 is rotated so as to prevent the screw shaft 3 from rotating. The rotational movement of the ball screw nut 4 may be transmitted to the motor M.

  Further, a friction member of a restraining means may be provided on the outer peripheral side of the outer cylinder 2 to restrain the movement of the outer cylinder 2, and further, a restraining means may be provided on the screw shaft 3.

  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 of the buffer in 1st Embodiment. It is a longitudinal cross-sectional view of the buffer in 2nd Embodiment. It is a longitudinal cross-sectional view of the buffer in 3rd Embodiment.

Explanation of symbols

2 Outer cylinder 3 Screw shaft 4 Ball screw nut 10 Shaft 11 Case 12 Eyes 14, 18 Friction plates 15, 20, 35 Friction member 16 Driving gear 17 Driven gear 19 Disc 30 Tube 31 Rod 32 Winding 33 Magnets D1, D2, D3 buffer H motion conversion mechanism M motor Y1, Y2, Y3 suppression means

Claims (5)

A shock absorber that attenuates expansion and contraction by electromagnetic force acting on a winding facing a magnet, and is provided with suppression means for suppressing expansion and contraction. A shock absorber comprising a motion conversion mechanism for converting linear motion during expansion and contraction into rotational motion, and a motor to which the rotational motion is transmitted, and the suppression means suppresses the linear motion or the rotational motion. The shock absorber according to claim 1 or 2, wherein the suppressing means uses a frictional force. 4. The shock absorber according to claim 3, wherein the suppressing means includes speed increasing means for increasing the speed of the rotational motion, and the accelerated rotational motion is suppressed by a frictional force. The restraining means is a speed increasing means comprising a driving gear linked to the output shaft of the motor, a driven gear meshing with the driving gear, an annular friction plate connected to the driven gear, and capable of being pressed toward the friction plate. The shock absorber according to claim 4, comprising a friction member provided.

Images