JP2003343647A - Electromagnetic buffer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress an effect of a damping force by moment of inertia, and to improve comfortableness of a vehicle in applying an electromagnetic buffer to a vehicle. <P>SOLUTION: The electromagnetic buffer comprises an electromagnetic buffer body having a ball screw nut 5 and a screw shaft 4 rotatably screwed into the ball screw nut 5, and a motor 3 connecting to the screw shaft via a power transmitting means. A linear motion of the ball screw nut 5 is converted to a rotation of the screw shaft 4 via the ball screw nut 5, the rotation is transmitted to a shaft 3a of the motor 3 via the power transmitting means to generate an electromagnetic force in the motor 3, and torque against the rotation of the shaft 3a caused by the electromagnetic force is used as a damping force for suppressing the linear motion of the ball screw nut 5. When the rotation of the screw shaft 4 is started or the speed is changed, the power transmitting means delays and transmits the rotation of the screw shaft to the shaft 3a of the motor 3. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a mechanism for converting a linear motion of a ball screw nut into a rotary motion of a motor via the screw shaft by rotatably screwing a screw shaft into the ball screw nut. The present invention relates to an electromagnetic shock absorber that generates a damping force by an electromagnetic force caused by a rotational movement of a shaft of a motor, and more particularly to improvement of a power transmission means for transmitting the rotational movement of the screw shaft to the motor.

[0002]

2. Description of the Related Art Generally, a suspension is known in which a hydraulic shock absorber is interposed between a vehicle body and an axle of a vehicle in parallel with a suspension spring. The suspension suspends the vehicle body and inputs vibrations and the like from the road surface. To improve the riding comfort and maneuverability of the vehicle, or suppress the displacement of the vehicle body to keep the vehicle height constant.

On the other hand, an electromagnetic shock absorber installed together with a hydraulic shock absorber and the like is incorporated in a part of the suspension, and when the vehicle body changes, an electric current is passed through the motor to generate an electromagnetic force. A vehicle suspension to be used is also known as disclosed in, for example, Japanese Patent Laid-Open No. 44758/1993.

However, the suspension using the hydraulic shock absorber described above requires oil, on the other hand, which can provide a high damping force, and requires a seal mechanism and a complicated valve mechanism for preventing the oil from leaking.

Similarly, a suspension using an electromagnetic shock absorber requires a power source, a controller, etc., which complicates the structure and is disadvantageous in terms of cost.

Therefore, recently, a new electromagnetic shock absorber which does not require oil, air, power source, etc. has been studied, and its paper has been published.

The basic structure of this electromagnetic shock absorber is, for example, as shown in the model of FIG. 2, a ball screw nut 5, a flange 34 for holding the ball screw nut 5, and a flange to which an eye-shaped bracket 38 is fixed. 37, a guide rod 36 that connects the flanges 34, 37, a screw shaft 4 that is rotatably screwed into a ball screw nut 5, and is coupled to the upper end of the screw shaft 4 via a coupling 2 and a shaft 3a. And the motor 3 that has been used.

When the electromagnetic shock absorber is used as a suspension by interposing it between the vehicle body and the axle, for example, a bracket whose upper end is fixed to a flange 28 provided on the motor 3 is used. 40 and the lower end of the electromagnetic shock absorber is connected to the vehicle body side through the eye-shaped bracket 3
Connect to the axle side via 8.

In this case, the motor 3 has a flange 3 at the lower end.
Connected to the flange 32 via 0 and the connecting rod 31,
The ball bearing 9 is fixed to the inner circumference of the flange 32, and the upper portion of the screw shaft 4 is rotatably inserted into the ball bearing 9.

Further, the flange 32 is connected to the flange 35 by a connecting rod 33, and the guide rod 36 is slidably inserted into a hole provided in the flange 35, so that the ball screw nut 5 moves linearly. Only that is acceptable.

According to the concept of the suspension using this electromagnetic shock absorber, for example, when the ball screw nut 5 linearly moves in the direction of arrow a by vibration input from the road surface, the screw shaft 4 in the ball screw nut 5 is The balls in the screw nut 5 and the threaded groove 3a on the outer periphery of the screw shaft 4 are guided to be converted into rotational movement.

Therefore, the rotational movement of the screw shaft 4 is transmitted as the rotational movement of the shaft 3a in the direction of the arrow b through the coupling 2 attached to the upper end of the screw shaft 4, whereby the induced electromotive force is generated in the motor 3. Although not shown in particular, if each electrode of the motor 3 is short-circuited without a power source or if it is connected to a control circuit so as to obtain a desired electromagnetic force,
A current resulting from the induced electromotive force flows through the solenoid in the motor 3, and the motor 3 generates an electromagnetic force.

At this time, if each electrode of the motor 3 is short-circuited or connected to a control circuit so that an electromagnetic force is generated in the direction opposite to the rotation direction of the shaft 3a, the electromagnetic force causes the electromagnetic force. Torque against the rotation of the shaft is generated, and the rotation of the shaft 3a of the motor 3 is suppressed.

Then, since suppressing the rotation of the shaft 3a means suppressing the rotation of the screw shaft 4,
The torque acts as a damping force that suppresses the linear movement of the ball screw nut 5.

That is, the above operation is performed by the ball screw nut 5
Is connected to the eye-shaped bracket 38, it acts as a damping force that suppresses the expansion and contraction movement of the electromagnetic shock absorber.

[0016]

However, a structure is adopted in which the rotational movement of the screw shaft 4 is transmitted to the motor 3 by connecting the above-mentioned conventional screw shaft 4 and the shaft 3a of the motor 3 with a coupling or the like. In the existing electromagnetic shock absorber, the following problems may occur when the electromagnetic shock absorber is actually applied to a vehicle.

That is, the screw shaft 4 rotates in accordance with the linear movement of the ball screw nut, and the rotational movement is transmitted to the motor 3. However, the inertia moment of the rotor inside the motor 3 is relatively large and the inertia force against the damping force is large. The impact cannot be ignored.

Here, what kind of influence the damping force has will be described.

Generally, the load (damping force) generated in the electromagnetic shock absorber is the sum of the moment of inertia of the rotor of the motor, the moment of inertia of the screw shaft, the moment of inertia of the coupling, and the electromagnetic force generated by the motor. The moment of inertia of the rotor is proportional to the acceleration of the expansion / contraction motion of the electromagnetic shock absorber because the angular acceleration of the shaft of the motor is proportional to the acceleration of the expansion / contraction motion of the electromagnetic shock absorber.

Since the moment of inertia of the rotor is proportional to the acceleration of the expanding / contracting motion as described above, the force of the motor against the axial force of the shock absorber input from the road surface to the electromagnetic shock absorber is increased. A damping force that does not depend on the electromagnetic force will be generated, and a particularly high damping force will be generated when a sudden force is input.

Therefore, the damping force due to the moment of inertia of the rotor of the motor is always generated prior to the damping force dependent on the electromagnetic force, and as described above, the moment of inertia of the rotor of the motor is relatively large. If the influence of the inertia moment of the rotor on the damping force can be suppressed, the riding comfort can be improved as compared with the case where the conventional electromagnetic shock absorber is applied to the vehicle.

Therefore, when controlling the electromagnetic shock absorber, it is difficult to control the damping force generated by the moment of inertia of the rotor of the motor that depends on the acceleration of the expansion / contraction motion of the electromagnetic shock absorber. It is preferable that the influence of the moment of inertia is small.

On the other hand, since the motor is more expensive than the other parts of the electromagnetic shock absorber, it is desirable to prevent the damage as much as possible. However, when the electromagnetic shock absorber is suddenly loaded with a large axial force, The speed of the expansion / contraction movement of the shock absorber increases, and the rotation speed of the screw shaft also increases in proportion to the speed of the expansion / contraction movement due to the structure of the electromagnetic shock absorber.

Then, the rotational movement of the screw shaft is transmitted to the shaft of the motor. However, when the load is abrupt, the rotational speed of the shaft is increased in proportion to the expansion / contraction speed of the electromagnetic shock absorber, like the rotational speed of the screw shaft. However, if the motor's permissible rotation speed is exceeded, the heat generated by the motor itself will deteriorate the insulation due to chemical changes in the insulating coating of the conductors forming the motor's solenoid, resulting in leakage of electricity, etc. There is a risk of damage.

Therefore, as described above, the motor is an indispensable component for generating the damping force of the electromagnetic shock absorber, and therefore the damage of the motor impairs the function of the electromagnetic shock absorber as the shock absorber.

Therefore, the present invention was devised in consideration of the above problems, and its purpose is to:
In particular, it suppresses the influence of the damping force due to the moment of inertia of the rotor of the motor, improves the ride comfort of the vehicle even when the electromagnetic shock absorber is applied to the vehicle, and damages it due to the heat generated by the motor. To prevent the repair of the electromagnetic shock absorber at low cost.

[0027]

In order to achieve the above-mentioned object, an electromagnetic shock absorber of the present invention comprises an electromagnetic shock absorber main body having a ball screw nut and a screw shaft rotatably screwed into the ball screw nut. A motor connected to the screw shaft via a power transmission means, converting the linear motion of the ball screw nut into a rotary motion of the screw shaft, and the rotary motion of the motor via the power transmission means. In the electromagnetic shock absorber, which is transmitted to the shaft to generate an electromagnetic force in the motor, and the torque that resists the rotation of the shaft due to the electromagnetic force is used as a damping force for suppressing the linear movement of the ball screw nut, The power transmission means is configured to delay the rotation of the screw shaft with time and transmit the rotation of the screw shaft to the shaft of the motor when the rotational motion of the screw shaft is started or when the speed changes. It is an.

More specifically, an elastically deformable member is used for all or part of the power transmission means, and all or part of the power transmission means is elastically deformed by the rotational torque of the screw shaft. When the rotational movement of the screw shaft is started or the speed is changed, the rotation of the screw shaft is delayed in time and transmitted to the shaft of the motor.

Further, the power transmission means is a torsion bar.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below based on the embodiments shown in the drawings.

FIG. 1 is a side sectional view of an electromagnetic shock absorber according to the present invention.

In the electromagnetic shock absorber according to the present invention, as shown in FIG. 1, the motor 3 is fixed above the outer cylinder 13 via the housing 8 and the case 7, and the shaft 3a of the motor 3 is inside the case 7. It is connected to the upper end of the screw shaft 4 via a torsion bar 1 and a coupling 2, which are power transmission means rotatably inserted into the screw shaft 4.

On the other hand, the screw shaft 4 is rotatably inserted into a ball bearing 9 fixed above the case 7 via bearing holding members 10 and 11, and a ball connected above the hollow rod 6. It is rotatably screwed into a screw nut 5, and this screw shaft 4, hollow rod 6, and ball screw nut 5
And constitute the electromagnetic shock absorber body D.

Although the outer cylinder 13 can be used without the outer cylinder 13, for example, when an electromagnetic shock absorber is mounted as a vehicle suspension, flying stones from the road surface, rainwater or the like can be directly fed to the ball screw nut 5 or the like. It is preferable to provide it in order to prevent the screw shaft 4 from hitting.

With the above structure, linear movement of the hollow rod 6 with respect to the screw shaft 4 due to thrust input or vibration while the vehicle is running from an axle side eye-shaped bracket (not shown) connected to the lower side of the hollow rod 6 causes the screw to move. By the combination of the shaft 4 and the ball screw nut 5, it is converted into rotational movement of the screw shaft 4, and the rotational movement of the screw shaft 4 is transmitted to the shaft 3a of the motor 3 through the torsion bar 1 and the coupling 2 which are the power transmission means. To be done.

Although the structure of the ball screw nut 5 is not particularly shown, for example, a spiral ball holding portion is provided on the inner circumference of the ball screw nut so as to match the spiral screw groove of the screw shaft. In addition, a large number of balls are arranged in the holding portion, and a passage is provided inside the ball screw nut so as to communicate the both ends of the spiral holding portion so that the balls can circulate. When the screw shaft is screwed into the ball screw nut, the ball of the ball screw nut fits into the spiral screw groove of the screw shaft, and the ball itself also rotates with the screw of the screw shaft. Since it rotates due to the frictional force with the groove, it can perform a smoother operation than a mechanism such as a rack and pinion.

As described above, the ball screw nut 5 is rotatably mounted on the screw shaft 4 along the screw groove, and when the ball screw nut 5 makes a linear movement in the vertical direction, the balls of the ball screw nut 5 are moved. It moves up and down, but at this time,
Since the ball moves along the spiral screw groove of the screw shaft 4, the screw shaft 4 is forcibly driven to rotate.

That is, the ball screw nut 5 is operated by the above mechanism.
Will be converted into the rotary motion of the screw shaft 4, and as a result, the linear motion of the hollow rod 6 will be converted into the rotary motion of the screw shaft 4.

The above mechanism is preferable as a mechanism for converting the linear motion of the hollow rod 6 into a rotary motion, but if the mechanism has the same effect, the ball screw nut 5 and the screw shaft 4 can be used.
It does not need to depend on the combination of.

Here, although not particularly shown, the motor 3 is connected to a control circuit or the like (not shown) or is directly connected to the motor 3.
Each electrode (not shown) is connected to form a closed circuit,
Moreover, by generating a torque that resists the rotation of the shaft 3a caused by the electromagnetic force, the electromagnetic force is generated in the motor, and it is necessary to adjust so that a desired damping force can be obtained. However, the transmitted rotational movement causes a magnetic field generated by a magnet (not shown) of the motor 3 to cross a solenoid (not shown) of the motor 3 and a current flows through the solenoid to generate an electromagnetic force. Due to this electromagnetic force, which will be described later, torque is generated in a direction that suppresses the rotational movement of the shaft 3a, the power transmission means, and the screw shaft 4, and the rotational movement of the screw shaft 4 is suppressed. It is possible to obtain a damping force that suppresses the linear movement in which the rod 6 appears and disappears.

That is, the motor 3 is used as an electromagnetic force generation source, and various motors such as a DC motor, an AC motor, an induction motor and the like can be used.

For example, taking a DC motor as an example,
Although not particularly shown, in the case of a DC brush motor, the motor 3 includes a plurality of permanent magnets for generating a magnetic field, a solenoid, an armature, a yoke, a commutator, a frame, and a shaft. A solenoid is formed by winding a conductive wire, and when the shaft rotates, the solenoid crosses the magnetic field generated by the permanent magnet to generate an induced electromotive force.

In the above DC motor example, the armature is a rotor because of its structure.

A shaft 3a is rotatably inserted in the motor 3 as shown in FIG.
From the above-exemplified configuration, it is possible to exhibit rotational motion as the electromagnetic force is generated.

Next, the power transmission means will be described in detail. As shown in FIG. 1, the power transmission means is composed of a torsion bar 1 as an elastically deformable member and a coupling 2 connected to the torsion bar 1. .

The torsion bar 1 is provided with an elongated rod-shaped torsion bar main body 1c, a lower connecting portion 1b having a diameter larger than that of the main body 1c provided below the main body 1c, and a lower end of the connecting portion 1b. The hole 1a and the upper connecting portion 1d provided at the upper end of the main body 1c are integrally formed.

The coupling 2 has a substantially cylindrical shape, and a screw hole for connecting the shaft 3a and the torsion bar 1 is provided on the upper and lower sides of the outer periphery of the coupling 2.

The shaft 3a is provided with a key groove 3b. When the key 3c is laterally inserted into the key groove 3b and the shaft 3a is inserted into the upper inner circumference of the coupling 2 and coupled, the shaft 3a Used to prevent the coupling 2 from slipping.

The upper end of the torsion bar 1 is inserted into the lower end of the coupling 2 and is connected to the coupling 2.

Further, the upper end of the screw shaft 4 is inserted into the hole 1a of the torsion bar 1 so that the screw shaft 4 and the torsion bar 1 are connected. Like the shaft 3a of the motor 3, a key 4a is provided on the upper end of the screw shaft 4, and the key 4a prevents the screw shaft 4 from idling with respect to the torsion bar 1.

Next, the operation will be described.

With the above-described structure, when the electromagnetic shock absorber is applied as a suspension of a vehicle, when a shock such as a push-up input from the road surface or vibration acts on the hollow rod 6 while the vehicle is traveling, the hollow rod 6 causes the hollow rod 6 to become an outer cylinder. A linear motion is made in the expansion / contraction direction along 13.

This linear movement is converted into rotational movement of the screw shaft 4 by the ball screw mechanism of the ball screw nut 5 and the screw shaft 4.

When the screw shaft 4 exhibits the rotational motion as described above, the torsion bar 1 also rotates because the torsion bar 1 is connected to the upper end portion of the screw shaft 4.

Then, since the torsion bar 1 and the coupling 2 are connected as described above, the rotational movement of the torsion bar 1 is transmitted to the coupling 2 and the coupling 2 also rotates.

The rotational movement of the coupling 2 causes the shaft 3a of the motor 3 to rotate because the coupling 2 is connected to the shaft 3a of the motor 3.

When the shaft 3a of the motor 3 exhibits a rotational motion, the solenoid in the motor 3 crosses the magnetic field of the magnet, an induced electromotive force is generated, and each electrode of the motor 3 is short-circuited as described above. Moreover, since a current flows through the solenoid so as to generate a torque that resists the rotation of the shaft 3a caused by the electromagnetic force of the motor 3, the torque that resists the rotation of the shaft 3a is the rotational movement of the shaft 3a. Will be suppressed.

Since the shaft 3a is connected to the screw shaft 4 via the torsion bar 1 and the coupling 2, the action of suppressing the rotational motion of the shaft 3a works to suppress the rotational motion of the screw shaft 4. .

Then, the torque against the rotation of the shaft 3a caused by the electromagnetic force of the motor 3 suppresses the rotational movement of the screw shaft 4, so that the linear movement of the hollow rod 6 along the outer cylinder 13 in the extension / contraction direction is performed. It acts as a suppressing damping force, absorbs and relaxes the impact energy from the road surface, improves the riding comfort of the vehicle, and improves the maneuverability.

As described above, the function as an electromagnetic shock absorber can be exhibited by a series of operations.

At this time, the torsion bar 1 which exhibits a rotational movement due to the rotational movement of the screw shaft 4 absorbs the force to rotate, that is, the torque, and absorbs the force. Since the torque is transmitted to the coupling 2 and thus the shaft 3a while being twisted, the rotational movement of the torsion bar 1 is not directly transmitted to the shaft 3a, and particularly when the screw shaft 4 starts rotating or changes in rotational speed. When there is such a change, a change in the rotation speed of the shaft 3a of the motor 3 is delayed in time with respect to a change in the rotation speed of the screw shaft 4.

Then, the above phenomenon is caused by the hollow rod 6
When there is a change in the expansion / contraction speed or in the expansion / contraction speed, that is, when the axial force of the electromagnetic shock absorber is applied to the hollow rod 6, the linear motion start of the hollow rod 6 relative to the outer cylinder 13 or the linear motion acceleration changes. In this case, it acts to delay the generation of the moment of inertia of the rotor of the motor 3 with respect to time.

This delays the generation of the damping force due to the moment of inertia of the rotor of the motor 3 in terms of time. When the electromagnetic shock absorber is applied to the vehicle, the ride comfort of the vehicle can be improved as compared with the conventional electromagnetic shock absorber.

Since the torsion bar 1 transmits the rotational movement of the shaft 3a of the motor 3 and the screw shaft 4, the torsion bar 1 is made of a material capable of ensuring strength against the torque caused by the screw shaft 4 or the motor 3. However, the intention of the present invention is to transmit the rotation of the screw shaft 4 to the shaft 3a of the motor 3 with a time delay when starting the rotational movement of the screw shaft 4 or when the speed changes. Therefore,
By design, the torsion bar rigidity of the torsion bar 1 is adjusted by changing the cross-sectional area and material of the cross section of the torsion bar 1 so that the deviation of the rotational speed is optimal for a vehicle to which an electromagnetic shock absorber is applied. Is preferred.

Further, for example, when the angular acceleration of the shaft 3a of the motor 3 due to the above-mentioned rotational torque changes from 0 to a certain value, a torque such that the rotational speed of the shaft 3a of the motor 3 reaches the allowable rotational speed after 1 second. Torsion bar 1
If the shear strength of the torsion bar 1 is set so that the torsion bar 1 will be disconnected when it is loaded on the vehicle, when the electromagnetic shock absorber is applied to a vehicle, the hollow rod 6 will suddenly reach a sharp road surface or the like. When the axial force due to the input from is applied, the torsion bar 1 is cut off, and the rotation speed of the shaft 3a caused by the rapid expansion and contraction movement of the electromagnetic shock absorber is suppressed from exceeding the allowable rotation speed of the motor 3. You can also do it.

As described above, since the rotation speed of the shaft 3a of the motor 3 can be suppressed from exceeding the allowable rotation speed of the motor 3, it is possible to prevent the motor 3 from being damaged by the heat generated by the motor 3 itself.

Further, when the electromagnetic shock absorber according to the present invention is applied to a vehicle, as described above, even if the torsion bar 1 is cut, the damping effect is lost, but a suspension spring is provided together with the electromagnetic shock absorber. If this is done, the vehicle will be in a state of being balanced by the suspension spring, and the situation in which the vehicle cannot run can be avoided.

Further, in the present embodiment, the torsion bar 1 is used as the power transmission means in consideration of the ease of mounting and processing. However, the present invention causes the above-mentioned deviation of the rotation speed, Since the main purpose is to delay the generation of the damping force due to the moment of inertia of the rotor of the motor 3 with time, an electromagnetic clutch, for example, may be used as the power transmission means.

As described above, the torsion bar 1 has a slender rod-shaped torsion bar body 1c and a lower connecting portion 1b having a diameter larger than that of the body 1c provided below the body 1c.
And a hole 1a provided at the lower end of the connecting portion and the main body 1c.
Although it is integrally formed with the upper connecting portion 1d provided at the upper end of the above, other shapes may be used as long as it has a portion that is twisted by the torque.

Since the coupling 2 is also used for transmitting power, it may have another shape, and its material is also sufficiently rigid with respect to the torque transmitted from the screw shaft 4 or the shaft 3a. However, it is desirable that the moment of inertia is as small as possible.

[0071]

According to the first aspect of the present invention, the power transmission means for delaying the rotation of the screw shaft to the shaft of the motor by delaying the rotation of the screw shaft when starting the rotational movement of the screw shaft or changing the speed. Since it is equipped with, it has the following effects.

When there is a change in the expansion / contraction speed of the electromagnetic shock absorber, the moment of inertia of the rotor of the motor can be generated at the start of expansion / contraction or with a time delay with respect to the change in the expansion / contraction speed. Therefore, since the generation of the damping force due to the moment of inertia of the rotor of the motor is delayed in time, the generation of the damping force due to the moment of inertia of the rotor of the motor at the initial expansion / contraction speed change of the electromagnetic shock absorber is suppressed. It will be different.

Similarly, it is possible to further reduce the adverse effects such as difficulty in controlling the damping force generated by the moment of inertia of the rotor.

Further, since it is possible to suppress the generation of the damping force due to the moment of inertia of the rotor of the motor in the initial stage of the expansion / contraction speed change of the electromagnetic shock absorber, when the electromagnetic shock absorber is applied to a vehicle,
It is possible to prevent the ride quality of the vehicle from being deteriorated.

According to the invention of claim 2,
An elastically deformable member is used for all or part of the power transmission means, and all or part of the power transmission means is elastically deformed by the rotational torque of the screw shaft, so that the rotational movement of the screw shaft is started or the speed is changed. Since the rotation of the screw shaft is delayed with respect to the time of change and transmitted to the shaft of the motor, the same effect as the invention of claim 1 can be obtained.

Further, according to the invention of claim 3,
In addition to the effects of the invention of claim 1 described above, the following effects are obtained because the power transmission means is a torsion bar.

The structure of the torsion bar is simple and easy to process, and it can be easily attached to the screw shaft and the shaft.

Further, by using the torsion bar, it is possible to set so that the main part of the torsion bar is disconnected when a certain torque is applied to the torsion bar. Then, when a certain torque is applied to the torsion bar, the torsion bar is disconnected, so that it is possible to prevent the rotation speed of the motor shaft from exceeding the allowable rotation speed of the motor.

That is, since the rotational speed of the shaft is suppressed from exceeding the allowable rotational speed of the motor, it is possible to suppress the temperature rise due to the heat generated by the motor itself.

Therefore, by suppressing the temperature rise, the chemical change of the insulating coating of the solenoid of the motor is suppressed, so that the damage of the motor such as the electric leakage can be effectively prevented.

Further, even if the torsion bar is cut, it is possible to prevent damage to the motor, which is more expensive than other parts. Therefore, even when the electromagnetic shock absorber is repaired, the torsion bar is replaced by Since the function as the electromagnetic shock absorber can be restored, there is an effect that the repair cost becomes low.

Further, when the electromagnetic shock absorber according to the present invention is applied to a vehicle, as described above, even if the torsion bar is cut, the damping effect is lost, but a suspension spring is provided together with the electromagnetic shock absorber. If this is done, the vehicle will be in a state of being balanced by the suspension spring, and it is possible to avoid the situation in which the vehicle cannot run.

[Brief description of drawings]

FIG. 1 is a side sectional view of an electromagnetic shock absorber according to the present invention.

FIG. 2 is a side sectional view of a conventional electromagnetic shock absorber.

[Explanation of symbols]

1 torsion bar 1a hole 1b Lower connection part 1c Torsion bar body 1d Upper connection part 2 coupling 3 motor 3a shaft 3b keyway 3c key 4 screw shaft 4a key 5 ball screw nuts 6 hollow rod D Electromagnetic shock absorber body

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takuhiro Kondo             2-4-1, Hamamatsucho, Minato-ku, Tokyo World Trade             Yasu Center Building Kayaba Industry Co., Ltd. F-term (reference) 3J048 AA07 BE09 EA16

Claims (3)

[Claims] 1. An electromagnetic shock absorber main body having a ball screw nut and a screw shaft rotatably screwed into the ball screw nut, and a motor coupled to the screw shaft via a power transmission means. The linear motion of the ball screw nut is converted into the rotary motion of the screw shaft, and this rotary motion is transmitted to the shaft of the motor through the power transmission means to generate an electromagnetic force in the motor. In an electromagnetic shock absorber that uses a torque against the rotation of the shaft as a damping force that suppresses the linear movement of the ball screw nut, the power transmission means includes the above-mentioned when the rotational movement of the screw shaft is started or when the speed changes. An electromagnetic shock absorber characterized in that the rotation of a screw shaft is delayed in time to be transmitted to the shaft of the motor. 2. An electromagnetic shock absorber main body having a ball screw nut and a screw shaft rotatably screwed into the ball screw nut, and a motor coupled to the screw shaft via a power transmission means. The linear motion of the ball screw nut is converted into the rotary motion of the screw shaft, and this rotary motion is transmitted to the shaft of the motor through the power transmission means to generate an electromagnetic force in the motor, and the shaft caused by the electromagnetic force. In the electromagnetic shock absorber that uses a torque against the rotation of the ball screw nut as a damping force that suppresses the linear movement of the ball screw nut, an elastically deformable member is used for all or part of the power transmission means, and By elastically deforming all or part of the power transmission means, the rotation of the screw shaft is delayed in time at the time of starting the rotational movement of the screw shaft or when the speed changes, and An electromagnetic shock absorber characterized by being transmitted to a shaft. 3. The electromagnetic shock absorber according to claim 1, wherein the power transmission means is a torsion bar.