JP4268894B2 - Electromagnetic shock absorber - Google Patents

Description

The present invention relates to an electromagnetic shock absorber that converts one rotational movement of a screw shaft and a screw nut into a rotational movement of a motor by screwing a screw shaft into the screw nut, and uses the electromagnetic force of the motor as a damping force.

  In general, a suspension is known in which a hydraulic shock absorber is interposed between a vehicle body and an axle in parallel with a suspension spring. This suspension suspends the vehicle body and attenuates input such as vibration from a road surface. The ride comfort and controllability are improved, or the vehicle height is kept constant by suppressing the displacement of the vehicle body. This hydraulic shock absorber is advantageous in that a high damping force can be obtained, but on the other hand, oil is required, and a seal mechanism and a complicated valve mechanism for preventing leakage of the oil are required.

  Therefore, recently, a new electromagnetic shock absorber that does not require oil, air, power supply, etc. has been studied and proposed (see Patent Document 1 and Non-Patent Document 1).

The basic structure of this electromagnetic shock absorber is composed of a screw shaft that is rotatably engaged with a ball screw nut, and a motor that is connected to one end of the screw shaft and short-circuits the electrode, and the ball screw nut is a shaft with respect to the screw shaft. The shaft of the motor and the shaft of the motor rotate, and the induced electromotive force generated by the rotation of the shaft attenuates the torque opposite to the direction of rotation of the shaft and the screw shaft to suppress the linear motion of the ball screw nut. It is used as power.
JP 2003-227543 A (paragraph number 0023, FIG. 1) Suematsu, Suda, "Study on Electromagnetic Suspension in Automobile", Japan Society for Automotive Engineers, Preprint of Academic Lecture, 2000, No4-00

  However, an electromagnetic shock absorber that employs a configuration that transmits the rotational movement of the screw shaft to the motor by connecting the above-described conventional screw shaft and the motor shaft is superior in that it does not require oil or air. However, there are the following problems.

  That is, in the conventional electromagnetic shock absorber, a motor is mounted for generating a damping force, but the motor cannot be used for other purposes. However, since the motor can be driven to rotate, it is desired to make this motor versatile so that it can be used for other purposes.

  Therefore, the present invention was created in consideration of the above-mentioned problems, and the object of the present invention is to make it possible to use a motor mounted on an electromagnetic shock absorber for purposes other than the generation of damping force. It is.

In order to achieve the above-described object, the problem solving means of the present invention includes a screw nut, a screw shaft screwed into the screw nut, and a motor, and the rotational movement of one of the screw shaft and the screw nut is controlled by the motor. The shaft of the screw nut and the screw shaft is transmitted to the shaft, and an electromagnetic force is generated in the motor, and the rotational movement of one of the screw shaft and the screw nut is suppressed by the torque generated due to the electromagnetic force. In the electromagnetic shock absorber that suppresses relative movement in the direction, electromagnetic clutches are provided at both ends of the shaft of the motor, and the rotational motion of one of the screw shaft and the screw nut is transmitted to the shaft through the one electromagnetic clutch. The rotational movement of the shaft can be transmitted to an external driven member via the other electromagnetic clutch.

According to the invention of claim 1, one electromagnetic clutch is in a state in which the connection between one of the screw shaft and the screw nut and the shaft is released, and the other electromagnetic clutch is in a state in which the shaft and the driven member are connected, By actively energizing the motor, the driven member can be driven. Therefore, in this electromagnetic shock absorber, the motor can be used not only for generating damping force but also for other purposes. In particular, when mounted on a vehicle, devices that require rotational power are mounted at various locations on the vehicle, so motors are provided at various locations, but motors mounted on electromagnetic shock absorbers can be used. Therefore, a motor for a vehicle-mounted device, for example, a compressor or the like used for adjusting the vehicle height of an air conditioner or an air suspension becomes unnecessary, and the vehicle can be reduced in weight and cost can be reduced.

  Furthermore, in a state where the driven member is connected to the shaft via the other electromagnetic clutch, a damping force can be generated even by the moment of inertia of the driven member, and by any chance the motor is damaged and the motor is caused by the electromagnetic force. Even in a state where it is impossible to generate the damping force, a situation where the damping force cannot be generated is avoided. Therefore, fail safe can be performed.

Also, if the torque for rotating one of the threaded shaft and the screw nut by a linear movement of the other axial direction of the screw shaft and screw nut becomes excessive, for example, an input pushing up the electromagnetic shock absorber from the road surface when applied to a vehicle When a sudden and large load such as the above is input to the electromagnetic shock absorber, if one electromagnetic clutch cuts off the current supply to the coil in the electromagnet, only one of the screw shaft and screw nut will rotate. The shaft does not rotate and the motor does not generate electromagnetic force. Therefore, in the above situation, the generation of damping force can be prevented, so that the impact is not transmitted to the vehicle body side, and the riding comfort in the vehicle can be improved.

Also, if one of the electromagnetic clutches is adjusted in advance so as to slip when excessive torque is applied, the rotation of one of the screw shaft and screw nut is not directly transmitted to the shaft, so the motor shaft Does not rotate, or even if it rotates, the number of rotations is lower than the number of rotations of the screw shaft and screw nut. Therefore, even if a sudden vibration is input, a large damping force is not generated. Can be improved. Furthermore, if the amount of current supplied to one of the electromagnetic clutches is controlled to control the state of slipping positively, adverse effects caused by the damping force caused by the moment of inertia of the rotor of the motor can be suppressed.

  Further, if the amount of current supplied to one electromagnetic clutch is controlled to control the torque itself that can be transmitted by one electromagnetic clutch, adverse effects due to the moment of inertia can be prevented, and the riding comfort in the vehicle is further improved. You can also.

Also, if the current supply to one electromagnetic clutch is cut off when the rotational speed of one of the screw shaft and screw nut exceeds the allowable rotational speed of the motor, the motor coil caused by abnormal heat generation of the motor Insulation deterioration due to chemical changes or the like of the insulating film of the conductive wire forming the conductor, and thus adverse effects such as leakage due to the deterioration of insulation and damage to the motor itself can be prevented.

When the torque that rotates one of the screw shaft and the screw nut by the linear motion of the other of the screw shaft and the screw nut exceeds a predetermined torque, for example, when this electromagnetic shock absorber is applied to a vehicle, When a sudden and large load such as a push-up input is input to the electromagnetic shock absorber, the torque release means suppresses or cancels the torque transmission, thus preventing the motor from generating a damping force or reducing the generated damping force. can do. Therefore, an impact is not transmitted to the vehicle body side, and the riding comfort in the vehicle is improved.

  The predetermined torque is set to a torque generated at the time of vibration input that deteriorates the riding comfort in the vehicle so as to be suitable for the vehicle to which the electromagnetic shock absorber is applied. Only when a large and sudden load is input to the electromagnetic shock absorber, the ride comfort in the vehicle can be improved by releasing the torque transmission.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of an electromagnetic shock absorber according to an embodiment of the present invention. FIG. 2 is a longitudinal sectional view of the electromagnetic clutch. FIG. 3 is a longitudinal sectional view of an electromagnetic shock absorber according to the second embodiment of the present invention.

  As shown in FIG. 1, the electromagnetic shock absorber according to the present embodiment includes a motor 1, a screw shaft 3, a ball screw nut 4 serving as a screw nut, and electromagnetic clutches D1 and D1 provided at both ends of a shaft 1a of the motor 1, respectively. 1, the screw shaft 3 is screwed to the ball screw nut 4, and the linear motion of the ball screw nut 4 in the vertical direction in FIG. 1 is converted into the rotational motion of the screw shaft 3, and this rotational motion is transferred to the motor 1. The electromagnetic force is generated in the motor 1 by transmission, and the torque that resists the rotation of the screw shaft 3 caused by the electromagnetic force is used as a damping force that suppresses the linear motion of the ball screw nut 43, The axial relative movement of the screw nut 4 and the screw shaft 3 can be suppressed.

  More specifically, the screw shaft 3 is formed with a screw groove 3a on the outer periphery thereof, and the upper part in FIG. 1 is inserted into the outer cylinder 5 having a bottomed cylindrical shape through a ball bearing 7 so as to be rotatable. The upper end of the screw shaft 3 is connected to one end of the electromagnetic clutch D1. Further, the screw shaft 3 is rotatably screwed into the ball screw nut 4, and a cushion member 15 is provided at the tip, that is, the lower end in FIG. 1, and the ball screw nut 4 moves downward in FIG. When the electromagnetic shock absorber is fully extended, the cushion member 15 provided at the lower end in FIG. 1 of the screw shaft 3 comes into contact with the lower end in FIG. 1 of the ball screw nut 4 so that the screw shaft 3 becomes the ball screw. The nut 4 is prevented from being pulled out, and the impact at the time of the maximum extension is alleviated, and at the time of the maximum compression, the screw shaft 3 is prevented from coming into contact with the bottom portion of the inner cylinder 6 to be described later to reduce the impact. .

  Here, although the structure of the ball screw nut 4 is not particularly illustrated, for example, a spiral ball holding portion is provided on the inner periphery of the ball screw nut 4 so as to coincide with the spiral screw groove 3 a of the screw shaft 3. A large number of balls are arranged in the holding portion, and a passage is provided in the ball screw nut 4 to communicate both ends of the helical holding portion so that the balls can circulate. When the screw shaft 3 is screwed into the ball screw nut 4, the ball screw nut 4 is fitted into the spiral screw groove 3a of the screw shaft 3, and the ball screw nut 4 is shown in FIG. Since the ball itself is rotated by the frictional force with the screw groove 3a of the screw shaft 3 along with the linear motion in the middle / up / down direction, a smooth operation is possible as compared with a mechanism such as a rack and pinion. Further, the ball screw nut 4 is connected to a bottomed cylindrical inner cylinder 6 via a bracket 10.

On the other hand, the shaft 1a of the motor 1 is connected to the other end side of the electromagnetic clutch D, which is a torque release means connected to the upper end of the screw shaft 3, and when the screw shaft 3 rotates, the electromagnetic clutch D1 passes through this electromagnetic clutch D1. The shaft 1a of the motor 1 can also rotate. The motor 1 is formed in the outer cylinder 5. Here, the motor 1 is formed as a brushless motor, and is a coil 1 wound around a core 11 attached to the outer cylinder 5 and a shaft 1a rotatably inserted into the outer cylinder 5 serving as a frame via ball bearings 9 and 10. 12 and a plurality of magnets 13 and 13 attached to the shaft 1 a, and the magnets 13 and 13 are provided to face the coil 12 and the core 11. That is, when the shaft 1a exhibits a rotational movement with respect to the frame, the magnets 13 and 13 are also rotated, so that an induced electromotive force is generated when the coil 12 crosses the magnetic field generated by the magnet. Each of the electrodes of the motor 1 is connected to a control circuit or the like (not shown), or is short-circuited to be a closed circuit so as to generate torque against the rotation of the shaft 1a caused by electromagnetic force. By adjusting, the desired damping force is adjusted. Further, a circuit for energizing the motor 1 is provided separately from the short circuit. This energization circuit is not used for generating damping force but is used when taking out the rotational output of the motor 1 described later. However, it may be used for adjusting damping force, and this electromagnetic buffer is activated. When used as a suspension, it is possible to drive the motor 1 by actively energizing the motor 1 so as to function not only as a shock absorber but also as an actuator. In the case of a brushless motor, a Hall element, a magnetic sensor, an optical sensor, or the like is mounted as a rotor position detecting means. However, as long as a torque due to electromagnetic force is simply generated, the position detecting means is used. There is no need to provide it. However, by providing the position detection means, it is possible to grasp the state of rotation of the rotor (rotation angle, angular velocity, etc.), which is convenient for motor control. For example, taking a Hall element as an example, it is necessary to energize the element from an external power source, but it is sufficient to supply a current by connecting an electric wire for energization to the element. Since power is generated by the rotation of the shaft 1a without using a power source, the current generated by the induced electromotive force is supplied to the Hall element, or is stored in an external battery and the current is supplied from the battery. It may be supplied. From the above description, the coil is attached to the frame and the magnet is attached to the shaft 1a. However, the coil may be attached to the shaft 1a and the magnet may be attached to the frame. 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.

  The electromagnetic clutch D1 can selectively connect and release the screw shaft 3 and the shaft 1a of the motor 1. The electromagnetic clutch D1 may be a known one that can connect and release the screw shaft 3 and the shaft 1a. Specifically, for example, as shown in FIG. 2, the shaft 1a of the motor 1 is used. An electromagnet holding member 51 rotatably mounted on the ball bearing 60, an electromagnet M in which a coil 52 is provided and fixed to the electromagnet holding member 51, a clutch plate 53 fitted to the shaft 1a, a clutch An annular friction plate 54 provided on the plate 53, a clutch plate holding member 56 that is rotatably attached to the shaft 1a via a ball bearing 55, and is fitted to the screw shaft 3, and a clutch plate holding member 56 And a clutch plate 58 that is swingably mounted via an annular leaf spring 57. When a current is applied to the coil 32, the clutch plate 58 is moved to the annular leaf spring 57. The clutch plate 58 is attracted to and brought into contact with the clutch plate 53 against the spring force, whereby the rotation of the screw shaft 3 is transmitted to the shaft 1a of the motor 1 and the coil 52 is de-energized. Since it is separated from the clutch plate 53 by the restoring force of 57, the rotation of the screw shaft 3 is not transmitted to the shaft 1a.

  Further, the above-described inner cylinder 6 is slidably inserted into the outer cylinder 5. Therefore, since the constituent members of the electromagnetic shock absorber are covered by the outer cylinder 5 and the inner cylinder 6, stepping stones, rainwater, etc. from the road surface directly hit the ball screw nut 4, the motor 1, the electromagnetic clutch D, and the screw shaft 3. Is prevented. Furthermore, since the inner cylinder 6 is slidably inserted into the outer cylinder 5, the shaft of the screw shaft 3 with respect to the inner cylinder 6 and the ball screw nut 4 is prevented, and a part of the ball screw nut 4 is prevented. It is possible to prevent a load from being concentrated on a ball (not shown) and to avoid a situation where the ball or the screw groove 3a of the screw shaft 3 is damaged. In addition, since the ball or the screw groove 3a of the screw shaft 3 can be prevented from being damaged, the smoothness of each operation of the rotation of the screw shaft 3 and the ball screw nut 4 or the movement of the electromagnetic shock absorber in the expansion / contraction direction can be maintained. Since the smoothness of each of the above operations can be maintained, the function as an electromagnetic shock absorber is not impaired, and consequently failure of the electromagnetic shock absorber can be prevented.

  Note that if a bearing is provided between the outer cylinder 5 and the inner cylinder 6, the risk that the inner periphery of the lower end portion of the outer cylinder 5 in FIG. 1 may bite the outer periphery of the inner cylinder 6 can be avoided. It is preferable to provide a bearing, and when a dust seal is provided at the lower end in FIG. 1 of the outer cylinder 5, the above-mentioned galling is prevented, so that the sealing performance between the outer cylinder 5 and the inner cylinder 6 is deteriorated due to the dust seal. Is also prevented.

  Incidentally, a bracket (not shown) is provided near the upper end of the outer cylinder 5, and a bracket (not shown) is also provided at the lower end of the inner cylinder 6. For example, the electromagnetic shock absorber is connected to the vehicle body side and the axle side of the vehicle. It can be inserted in between.

  Further, an electromagnetic clutch D2 is provided at the upper end of the motor 1 with respect to the shaft 1a, and this electromagnetic clutch D2 is connected to a rotating shaft H of a driven member outside the electromagnetic shock absorber. Specifically, for example, if this driven member is a vehicle-mounted device, it may be a compressor or the like used for adjusting the vehicle height of an air conditioner or an air suspension, or any other member that is rotationally driven. . Further, since the electromagnetic clutch D2 has the same configuration as the electromagnetic clutch D1, the description of the specific configuration is omitted. However, as with the electromagnetic clutch D1, a known electromagnetic clutch other than the above-described configuration can be used. It can be used.

  Subsequently, the operation will be described. When the inner cylinder 6 expands and contracts to the electromagnetic shock absorber, that is, when the inner cylinder 6 moves in the vertical direction in FIG. 1, the ball screw nut 4 connected to the inner cylinder 5 also performs a linear motion in the vertical direction. The linear motion of the ball screw nut 4 is converted into rotational motion of the screw shaft 3 by the ball screw mechanism of the ball screw nut 4 and the screw shaft 3.

  Here, in a state in which the electromagnetic clutch D1 connects the screw shaft 3 and the shaft 1a, that is, in a state in which the rotational motion of the screw shaft 3 is transmitted to the shaft 1a, when the screw shaft 3 exhibits the rotational motion, 1a also rotates. Then, the coil 12 in the motor 1 crosses the magnetic field of the magnets 13 and 13, and an induced electromotive force is generated in the coil 12. As described above, each electrode of the motor 1 is short-circuited. Generates torque against the rotation of the shaft 1a caused by the induced electromotive force. The torque against the rotation of the shaft 1a suppresses the rotation of the screw shaft 3 and the linear motion of the ball screw nut 4 because the shaft 1a is connected to the screw shaft 3.

  Therefore, the action of suppressing the rotational movement of the shaft 1a of the motor 1 works to suppress the linear movement of the ball screw nut 4, so that it acts as a damping force that suppresses the linear movement of the ball screw nut 4, and the vibration energy is reduced. Absorb absorption.

  As described above, the function as an electromagnetic shock absorber can be exhibited by a series of operations. Here, the electromagnetic clutch D2 is connected to the shaft 1a and the shaft H of the driven member under a situation where the electromagnetic shock absorber expands and contracts. In the state where the rotational movement of the shaft 1a is not transmitted to the shaft H, as described above, the axial direction of the ball screw nut 4 and the screw shaft 3 with the torque caused by the electromagnetic force generated only by the motor 1 as described above. In contrast, when the electromagnetic clutch D2 connects the shaft 1a and the shaft H of the driven member, that is, when the rotational motion of the shaft 1a is transmitted to the shaft H, the shaft H is The driven member is driven to rotate, but at this time, the moment of inertia of the driven member itself works to increase the damping force generated by the electromagnetic shock absorber. In other words, the damping force generated by the electromagnetic shock absorber is not caused by the electromagnetic force generated by the motor, but the rotor of the motor, specifically, the shaft 1a of the motor 1 and the motor 1 in this embodiment. Some are caused by the moment of inertia of the magnet attached to the shaft 1a. Further, when the driven member is connected to the shaft 1a via the electromagnetic clutch D2, the damping caused by the moment of inertia of the driven member itself. Force will be generated. Therefore, in a state where the driven member is connected to the shaft 1a via the electromagnetic clutch D2, the damping force generated by the electromagnetic shock absorber is the inertia moment of the rotor of the motor 1, the inertia moment of the screw shaft, the motor 1 The sum of the generated electromagnetic force and the moment of inertia of the driven member is such that the angular acceleration of the shaft 1a of the motor 1 is proportional to the acceleration of the expansion and contraction motion of the shock absorber. Therefore, it is proportional to the acceleration of the expansion and contraction motion of the shock absorber.

  Therefore, if the motor 1 cannot generate electromagnetic force for some reason, the damping force that can be generated by the electromagnetic shock absorber is generally caused by the moment of inertia of the rotor of the motor 1 and the screw shaft 3, but the electromagnetic clutch D1. , D2 in the connected state, a damping force can be generated by the moment of inertia of the driven member, and even if the motor 1 is damaged and the motor 1 cannot generate torque due to electromagnetic force. The situation where the damping force cannot be generated is avoided. Therefore, fail safe can be performed.

  When the torque for rotating the screw shaft 3 is excessive due to the vertical movement of the ball screw nut 4, for example, when this electromagnetic shock absorber is applied to a vehicle, a sudden and large load such as a push-up input from the road surface is applied. When input to the electromagnetic shock absorber, if the electromagnetic clutch D1 cuts off the current supply to the coil in the electromagnet, only the screw shaft 3 will rotate, the shaft 1a will not rotate, and the motor 1 will have electromagnetic force. Does not occur. Therefore, in the above situation, the generation of damping force can be prevented, so that the impact is not transmitted to the vehicle body side, and the riding comfort in the vehicle can be improved.

  Further, the electromagnetic clutch D1 may be adjusted in advance so as to be in a idling state, that is, a so-called slipping state even when the clutch plate 53 and the clutch plate 58 are in contact with each other when an excessive torque load is applied. In this case, what is necessary is just to adjust the electric current amount so that it may be in the said state according to the specification of an electromagnet. By doing so, since the rotation of the screw shaft 3 is not directly transmitted to the shaft 1a, the electromagnetic clutch D1 has a rotation speed lower than the rotation speed of the screw shaft 3 even if the shaft 1a of the motor 1 does not rotate or rotates. Therefore, even if a sudden vibration is input, a large damping force is not generated, so that the riding comfort in the vehicle can be improved. Furthermore, if the amount of current supplied to the electromagnetic clutch D1 is controlled to positively control the state in which the clutch plate 33 and the clutch plate 38 slide, the adverse effects caused by the damping force caused by the moment of inertia of the rotor of the motor 1 can be suppressed. can do.

  In the above description, the fail safe due to the moment of inertia has been described. However, in the normal state, that is, in a state where the motor 1 can generate an electromagnetic force, the moment of inertia is, as described above, the expansion / contraction motion of the electromagnetic shock absorber. Since it is proportional to the acceleration, the axial direction of vibration input to the electromagnetic shock absorber, especially when the electromagnetic shock absorber is applied to a vehicle, is particularly abrupt in the axial direction such as when pushing up from the road surface etc. When the vibration is input, a higher damping force is generated by the moment of inertia. Therefore, the damping force due to the moment of inertia of the rotor of the motor is always generated prior to the damping force depending on the electromagnetic force, and furthermore, the moment of inertia of the rotor of the motor is relatively large. Will get worse.

  Here, the electromagnetic clutch D1 can also control the transmission of torque by the electromagnetic force generated by the motor 1, and as described above, the torque caused by the electromagnetic force more than necessary cannot be transmitted to the screw shaft 3. Therefore, if the amount of current that can be transmitted to the electromagnetic clutch D1 is controlled by controlling the amount of current supplied to the electromagnetic clutch D1, it is possible to prevent the adverse effects caused by the moment of inertia and further improve the riding comfort in the vehicle. It can also be improved.

  Further, if the current supply to the electromagnetic clutch D1 is cut off when the rotational speed of the screw shaft 3 exceeds the allowable rotational speed of the motor 1, a conductor that forms a motor coil caused by abnormal heat generation of the motor. Insulation deterioration due to chemical change of the insulating coating, and thus adverse effects such as leakage due to the deterioration of insulation and damage to the motor itself can be prevented.

  Subsequently, when no vibration is input to the electromagnetic shock absorber, the electromagnetic clutch D1 releases the connection between the screw shaft 3 and the shaft 1a. On the other hand, the electromagnetic clutch D2 is connected to the shaft 1a and the shaft H. Further, the motor 1 is positively energized. Then, although the motor 1 is rotationally driven by energization, this rotation is transmitted to the shaft H of the driven member, and the driven member can be driven. Therefore, in this electromagnetic shock absorber, the motor 1 can be used not only for generating a damping force but also for other purposes. In particular, when mounted on a vehicle, since devices that require rotational power are mounted at various locations in the vehicle, motors are provided at various locations, but the motor 1 mounted in an electromagnetic shock absorber is used. Therefore, a motor for a vehicle-mounted device, for example, a compressor or the like used for adjusting the vehicle height of an air conditioner or an air suspension becomes unnecessary, and the vehicle can be reduced in weight and cost can be reduced.

  Next, a second embodiment will be described. In addition, about the member similar to 1st Embodiment, suppose that detailed description is abbreviate | omitted only to attach | subject the same code | symbol. As shown in FIG. 3, the electromagnetic shock absorber according to the second embodiment is configured such that the motor 31, the screw shaft 3, the housing 39, the ball screw nut 4, and the ball screw nut 4 are rotated by the shaft of the motor 31. A gear mechanism G for transmission to 31a, an electromagnetic clutch D1 provided between the gear mechanism G and the shaft 31a, and an electromagnetic clutch D2 provided between the upper end in FIG. 3 of the shaft 31a and the shaft H of the driven member. The screw shaft 3 is screwed onto the ball screw nut 4, the linear motion of the screw shaft 3 is converted into the rotational motion of the ball screw nut 4, and the rotational motion is converted via the gear mechanism G to the shaft 31 a of the motor 31. The motor 31 generates an electromagnetic force, and the torque that resists the rotation of the shaft 31a due to the electromagnetic force is used as a damping force that suppresses the linear motion of the screw shaft 3. In which it is possible to suppress the relative axial movement of the child nut 4 and screw shaft 3. That is, in the first embodiment, the screw shaft 3 rotates. In the second embodiment, conversely, the linear motion in the axial direction of the screw shaft 3 is changed to the rotational motion of the ball screw nut 4. In other words, the rotational movement of the ball screw nut 4 is transmitted to the shaft 31a of the motor 31.

 The detailed structure will be described below. As in the first embodiment, the screw shaft 3 is provided with a screw groove 3a on its outer periphery, and a bracket B is attached to the lower end in FIG. 1 so that it can be attached to a location where an electromagnetic shock absorber is applied. Is provided. The screw shaft 3 is rotatably screwed into the ball screw nut 4 and inserted into the outer cylinder 35 as in the first embodiment.

  The outer cylinder 35 is a bottomed cylinder, and a bracket (not shown) is provided at the upper end in FIG. 1 so that the outer cylinder 35 can be attached to a location where an electromagnetic shock absorber is applied. Therefore, when this electromagnetic shock absorber is applied particularly to a vehicle, the electromagnetic shock absorber can be interposed between the vehicle body and the axle via the bracket B and a bracket (not shown). .

  1 is connected to a hollow housing 39. The housing 39 is provided with holes 39a, 39b, 39c and a hole 39d. The outer cylinder 35 is provided with a hole 39a in the housing 39. , 39b are connected to the housing 39 so as to be concentric. Further, ball bearings 40 and 41 are fitted to the inner circumferences of the holes 39a and 39b of the housing 39, and the ball screw nut 4 is fitted into the ball bearings 40 and 41, respectively. Therefore, the ball screw nut 4 can rotate with respect to the housing 39.

  Ball bearings 42 and 43 are also provided in the hole 39 c and the hole 39 d of the housing 39, and the rotary shaft 50 is fitted in the ball bearings 42 and 43. Further, a cylinder 45 is coupled to the housing 39 so as to be concentric with the hole 39c, and the motor 31 is fixed inside the cylinder 45.

  Since the motor 31 has the same configuration as the motor 1 of the first embodiment, the internal structure is not particularly shown, but various motors can be used as in the first embodiment.

  As described above, when the screw shaft 3 is rotatably engaged with the ball screw nut 4 along the screw groove 3a, and the screw shaft 3 moves linearly in the vertical direction in FIG. Since the screw nut 4 is restricted from moving in the vertical direction in FIG. 3 by the housing 39 and is only allowed to rotate, the ball screw nut 4 is forcibly rotated. That is, the linear motion of the screw shaft 3 is converted into the rotational motion of the ball screw nut 4 by the above mechanism.

  On the other hand, the gear mechanism G includes a driven gear 32a formed on the outer periphery of the rotary shaft 50 and a drive gear 32b formed on the outer periphery of the ball screw nut 4, as shown in FIG. The teeth are horizontally disposed so as to mesh with each other and are rotatably inserted into the housing 39.

  Each of the gears 32a and 32b may be a well-known gear such as an involute gear. For example, two gears are used in the present embodiment. The effects of the invention can be realized.

  As described above, since the shaft centers of the gears 32a and 32b are offset in the lateral direction, the shaft center of the motor 31 coupled to the gears 32a and 32b and the shaft center of the ball screw nut 4 are shifted in the lateral direction. As a result, the motor 31 is arranged in parallel to the side of the ball screw nut 4 outside the outer cylinder 35.

  In the present embodiment, the motor 31 is disposed in the vicinity of the side of the ball screw nut 4, but the motor 31 is disposed at a position away from the ball screw nut 4 using the gear train as described above. It is also possible to do. Therefore, for example, it is possible to prevent the motor 31 from being damaged by rainwater, mud, stepping stones, etc. by arranging only the motor 31 in the vehicle body.

  With the above configuration, the rotational motion of the ball screw nut 4 by the linear motion of the screw shaft 3 in the vertical direction in FIG. 3 is transmitted to the shaft 31a of the motor 31 because the drive gear 32b and the driven gear 32a are engaged with each other. As a result, the motor 31 rotates, and the torque that resists the rotation of the shaft 31a caused by the electromagnetic force acts as a damping force that suppresses the rotation of the ball screw nut 4 via the gear mechanism G. .

  In the above description, the drive gear and the driven gear are horizontally arranged to transmit the rotational motion of the ball screw nut 4 to the motor 31. However, each gear is used as a bevel gear and the motor 31 is attached to the ball screw nut 4. It is also possible to change the angle. In this case, since the attachment angle can be adjusted, the electromagnetic shock absorber according to the present invention can be attached according to the structure of the vehicle to be applied. Therefore, it is possible to attach the electromagnetic shock absorber without being influenced by the layout of a new or existing vehicle. Further, any type of bevel gear may be used, but a helical bevel gear or the like capable of smooth transmission is preferable.

  Furthermore, in order to transmit the rotational motion of the ball screw nut 4 to the shaft 31 a of the motor 31, in addition to the gear mechanism G, a friction wheel mechanism or a belt mechanism may be used.

  And in 2nd Embodiment, as above-mentioned, one electromagnetic clutch D1 is provided between the said rotating shaft 50 and the shaft 31a, and the other electromagnetic clutch D2 is the shaft 31a and a to-be-driven member. Between the two shafts H.

  Subsequently, as to its action, when the electromagnetic shock absorber according to the second embodiment expands and contracts, the screw shaft 3 exhibits a linear motion up and down in FIG. 3, and this linear motion is the ball screw nut 4. Further, the rotational motion of the ball screw nut 4 is transmitted to the shaft 31a via the gear mechanism G. Therefore, in the second embodiment, the torque that resists the rotation of the shaft 31 a caused by the electromagnetic force generated by the motor 31 suppresses the rotation of the ball screw nut 4, and the rotation of the ball screw nut 4. As a result, the linear movement of the screw shaft 3 is suppressed, and as a result, it acts as a damping force that suppresses the relative movement of the ball screw nut 4 and the screw shaft 3 in the axial direction.

  Therefore, as in the first embodiment, a function as an electromagnetic shock absorber can be exhibited by a series of operations. Here, the shaft 31a of the motor 31 rotates via one electromagnetic clutch D1. Since the shaft 50 is connected to the shaft H of the coupled member via the other electromagnetic clutch D2, it is possible to achieve the same effect as that of the first embodiment. That is, in a state where the electromagnetic shock absorber expands and contracts, the electromagnetic clutch D1 and the electromagnetic clutch D2 connect the shaft 31a and the rotating shaft 50, respectively, and connect the shaft 31a and the shaft H of the driven member. The moment of inertia of the member itself works to increase the damping force generated by the electromagnetic shock absorber. Therefore, even if the motor 31 is damaged and the motor 31 cannot generate torque due to the electromagnetic force, a situation where the damping force cannot be generated is avoided. Therefore, fail safe can be performed.

  When no vibration is input to the electromagnetic shock absorber, the electromagnetic clutch D1 is brought into a state of releasing the connection between the rotary shaft 50 and the shaft 31a, and the electromagnetic clutch D2 is connected between the shaft 31a and the shaft H. When the motor 31 is actively energized, the motor 31 is rotationally driven by energization. This rotation is transmitted to the axis H of the driven member, and the driven member can be driven. Therefore, in this electromagnetic shock absorber, the motor 31 can be used not only for generating damping force but also for other purposes. In particular, when mounted on a vehicle, since devices that require rotational power are mounted at various locations in the vehicle, motors are provided at various locations, but the motor 31 mounted in an electromagnetic shock absorber is used. Therefore, a motor for a vehicle-mounted device, for example, a compressor or the like used for adjusting the vehicle height of an air conditioner or an air suspension becomes unnecessary, and the vehicle can be reduced in weight and cost can be reduced.

  Further, similarly to the first embodiment, by controlling the electromagnetic clutch D1 side, it is possible to prevent the motor 31 from being damaged, to prevent harmful effects caused by the moment of inertia, and to improve the riding comfort in the vehicle.

  In the above description, the case where the electromagnetic shock absorber is applied particularly to a vehicle has been described. However, it goes without saying that the electromagnetic shock absorber can be used in a portion where the normal shock absorber is used.

  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 electromagnetic shock absorber in the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of an electromagnetic clutch. It is a longitudinal cross-sectional view of the electromagnetic shock absorber in the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,31 Motor 1a, 31a Shaft 3 Screw shaft 3a Screw groove 4 Ball screw nut which is a screw nut 5,35 Outer cylinder 6 Inner cylinder D1, D2 Electromagnetic clutch

Claims (1)

A screw nut, a screw shaft that is screwed into the screw nut, and a motor are provided. One of the rotational movements of the screw shaft and the screw nut is transmitted to the shaft of the motor, and electromagnetic force is generated in the motor. In the electromagnetic shock absorber that suppresses the relative movement in the axial direction of the screw nut and the screw shaft by suppressing the rotational movement of one of the screw shaft and the screw nut with the torque generated due to the electromagnetic force. Electromagnetic clutches are provided at both ends, and the rotational movement of one of the screw shaft and screw nut is transmitted to the shaft through the one electromagnetic clutch, and the rotational movement of the shaft is externally transmitted through the other electromagnetic clutch. An electromagnetic shock absorber that can be transmitted to a driven member.

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