JP2008143436A - Electromagnetic shock absorber for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic shock absorber with high practicality. <P>SOLUTION: This electromagnetic shock absorber 10 is provided with a screw rod 80 having one end part connected to a spring lower part 36 and a nut 82 rotatably held in a spring upper part 54 and screwed with the screw rod 80, and generates damping force in relation to relative moving of the spring upper part 54 and the spring lower part 36 by imparting rotational force to the nut 82 based on motor force. The shock absorber 10 is constituted to inhibit the screw rod 80 from rotating around an axis, while permitting the screw rod 80 to move in an axial direction in relation to the spring upper part, by inhibiting relative rotation of an engaging hole 84 formed to be opened on an end face at the other end part of the screw rod 80 and extended in the axial direction and an engaging rod 88 fixed to the spring upper part 54 and fitted into the engaging hole 84, while permitting relative moving of the engaging hole 84 and the engaging rod 88. The absorber can be made compact by such a structure. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a shock absorber for a vehicle, and more particularly, an electromagnetic that generates a damping force with respect to relative movement between an upper part and an unsprung part based on a force generated by an electromagnetic motor (hereinafter sometimes referred to as “motor force”). The present invention relates to a vehicle type shock absorber.

In the field of vehicles, in recent years, the development of electromagnetic shock absorbers (hereinafter sometimes abbreviated as “absorbers”) that have the function of attenuating the relative vibration between the sprung portion and the unsprung portion based on the motor force has been promoted. It has been. The absorber described in the following patent document is an example of the electromagnetic absorber.
JP 2005-264992 A JP 2005-271738 A

  Since the electromagnetic absorber for vehicles described in the above-mentioned patent document has just been developed, it is still under development, leaving much room for improvement. Therefore, it is considered that the utility of the absorber is improved by various improvements. This invention is made | formed in view of such a situation, and makes it a subject to provide the electromagnetic-type absorber for vehicles with high practicality.

  In order to solve the above-described problems, the electromagnetic absorber for a vehicle according to the present invention has a screw rod whose one end is connected to one of the spring upper part and the spring lower part, and is rotatably held on the other of the spring upper part and the spring lower part. This is an electromagnetic absorber that includes a nut that is screwed with a screw rod, and that generates a damping force relative to the relative movement between the spring top and the spring bottom by applying a rotational force to the nut based on the motor force. In addition, an engagement hole that opens in the end surface and extends in the axial direction is formed at the other end of the screw rod, and an engagement rod that fits into the engagement hole is fixed to the other of the spring upper part and the spring lower part. The movement of the engagement rod with respect to the engagement holes is allowed while the relative rotation of the engagement rods is prohibited, thereby allowing the screw rod to move in the axial direction with respect to the other of the sprung portion and the unsprung portion. Do not rotate Configured to.

  In an electromagnetic absorber that employs a screw mechanism and has a structure that relies on the motor force to apply a rotational force to the nut, the screw rod connected to one of the spring upper part and the spring unsprung is connected to the spring upper part and the spring. It must be movable in the axial direction of the screw rod and non-rotatable with respect to the other of the lower part. According to the electromagnetic absorber of the present invention, rotation of the screw rod is prohibited while allowing the screw rod to move in the axial direction using the inside of the screw rod. With such a structure, the electromagnetic absorber of the present invention is made compact, for example, and as a result, the practicality is improved.

Aspects of the Invention

  In the following, some aspects of the invention that can be claimed in the present application (hereinafter sometimes referred to as “claimable invention”) will be exemplified and described. As with the claims, each aspect is divided into sections, each section is numbered, and is described in a form that cites the numbers of other sections as necessary. This is merely for the purpose of facilitating the understanding of the claimable inventions, and is not intended to limit the combinations of the constituent elements constituting those inventions to those described in the following sections. In other words, the claimable invention should be construed in consideration of the description accompanying each section, the description of the embodiments, etc., and as long as the interpretation is followed, another aspect is added to the form of each section. In addition, an aspect in which constituent elements are deleted from the aspect of each item can be an aspect of the claimable invention. In the following items, items (1) to (4) correspond to claims 1 to 4, respectively.

(1) (a) One end part is connected to one of the spring upper part and the spring lower part, and a screw rod having a male screw formed on the outer peripheral part, and (b) the other of the spring upper part and the spring lower part is rotatably held. A nut formed with an internal thread and screwed with the screw rod; and (c) a rotational force applying device that has an electromagnetic motor and applies a rotational force to the nut based on a force generated by the electromagnetic motor. An electromagnetic shock absorber for a vehicle that generates a damping force with respect to relative movement between the sprung portion and the unsprung portion,
The screw rod has an engagement hole that opens in the end surface and extends in the axial direction at the other end that is the end opposite to the one end, and
The shock absorber
(A) the engagement hole; (B) an engagement rod fixed to the other of the spring upper part and the spring unsprung and fitted into the engagement hole; and (C) the engagement rod and the screw rod. And a mechanism that prohibits relative rotation of the screw rod in the axial direction while prohibiting relative rotation thereof, and allows movement of the screw rod in the axial direction relative to the other of the spring upper portion and the spring unsprung portion. An electromagnetic shock absorber for a vehicle comprising a screw rod rotation prohibiting device that prohibits rotation of the screw rod.

  Many electromagnetic shock absorbers (hereinafter sometimes abbreviated as “absorbers”) employ a screw mechanism as a motion conversion mechanism, and a motor force is applied to the upper and lower springs via the motion conversion mechanism. Thus, a damping force is generated with respect to the relative movement between the sprung portion and the unsprung portion. The electromagnetic absorber having such a structure includes a structure that applies a rotational force to a nut based on a motor force and a structure that applies a rotational force to a screw rod based on a motor force. Each type of electromagnetic absorber has its advantages and disadvantages. To make the electromagnetic absorber more compact, the former structure is desirable as described in detail later. In the aspect, the electromagnetic absorber having the former structure is assumed. In the electromagnetic absorber having this structure, the rotational force of the nut is converted into a force in the axial direction of the screw rod, and the relative vibration between the spring top and the spring bottom is attenuated by the force. For this reason, the screw rod connected to one of the sprung portion and the unsprung portion needs to be allowed to move in the axial direction and prohibited from rotating with respect to the other of the sprung portion and the unsprung portion. .

  In order to prohibit the rotation of the screw rod while allowing the screw rod to move in the axial direction, for example, on the outer periphery of the screw rod, while allowing the relative movement of the other of the screw rod, the upper part of the spring and the lower part of the spring, It is also possible to prohibit rotation. However, when such a device is provided on the outer periphery of the screw rod, the absorber becomes longer in the axial direction thereof. In the aspect of this section, the inside of the screw rod is used to prohibit the rotation of the screw rod while allowing the movement of the screw rod in the axial direction. Therefore, according to the aspect of this section, for example, a compact electromagnetic absorber Can be achieved. In other words, in the electromagnetic absorber according to the aspect of this section, for example, it is possible to lengthen the expansion / contraction stroke of the absorber as much as the length can be shortened.

  “Spring part” in this section means, for example, a part of a vehicle body supported by a suspension spring, and “sprung part” means, for example, a wide range of vehicle components that move up and down together with a wheel shaft, such as a suspension arm. means. Incidentally, the electromagnetic absorber according to this aspect is arranged in parallel with the suspension spring, but the type of suspension spring is not limited to a compression coil spring, a leaf spring, an air spring, or the like. . In addition, the “connection between one of the spring upper part and the spring lower part and the screw rod” in the aspect of this section may be a direct connection, for example, indirectly through an elastic body, a damper device, or the like. It may be connected.

  The specific mechanism of the “mechanism for allowing relative movement between the engagement rod and the screw rod and prohibiting relative rotation thereof” described in this section is not particularly limited. A key groove (guide groove) is provided on one of the outer peripheral surface of the rod and the peripheral wall surface of the engagement hole of the screw rod so as to extend in the axial direction of the screw rod, and a key is provided on the other of them. The engagement rod and the screw rod may be spline-fitted as will be described in detail later.

  (2) The screw rod rotation prohibiting device as a mechanism for prohibiting the relative rotation of the mechanism that allows the engagement hole and the engagement rod to be spline-fitted while allowing the relative movement in the axial direction thereof. The electromagnetic shock absorber for a vehicle according to item (1), including the electromagnetic shock absorber.

  The mode described in this section is a structure of a mechanism that prohibits the relative rotation of the engaging rod and the screw rod in the axial direction while prohibiting the relative rotation of the engaging rod and the screw rod (hereinafter, sometimes referred to as “movement allowable rotation prohibiting mechanism”). Is a specifically limited embodiment. According to the aspect of this section, for example, it is possible to effectively realize the allowance of relative movement between the engagement rod and the screw rod and the prohibition of rotation. In addition, if, for example, a ball spline mechanism is employed as the movement-allowed rotation prohibiting mechanism described in this section, it is possible to realize a smooth relative movement between the engagement rod and the screw rod.

  (3) The electromagnetic motor has a generally cylindrical motor shaft, and one end portion of the motor shaft holds the nut and is disposed with the screw rod passing through the motor shaft (1 ) Or electromagnetic shock absorber for vehicle according to item (2).

  The mode described in this section is a mode in which the structure of the electromagnetic motor is specifically limited. In the aspect described in this section, an electromagnetic motor having a hollow motor shaft is adopted, and a screw rod is passed through the motor shaft, so that the electromagnetic absorber is made compact in the axial direction. Can be achieved.

  (4) The shock absorber includes an elastic body that elastically connects one end of the screw rod and one of the spring upper part and the spring lower part, and the screw rod and the spring upper part arranged in parallel with the elastic body. The electromagnetic shock absorber for a vehicle according to any one of (1) to (3), further comprising a damper device that generates a damping force with respect to relative movement between the first spring and one of the unsprung parts.

  The aspect described in this section is an aspect in which a limitation relating to the connection structure of the screw rod and one of the sprung portion and the unsprung portion is added. According to the aspect of this section, for example, it is possible to realize an absorber that can effectively absorb high-frequency vibration that the operation of the electromagnetic motor cannot follow, such as vibration in the unsprung resonance frequency range. Is possible. When the connection structure as in the aspect of this section is adopted, depending on the connection structure, the rotation of the screw rod may not be strictly prohibited. Therefore, the above-described screw rod rotation prohibiting device is particularly suitable for the electromagnetic absorber having the above connection structure.

  Various springs can be employed for the “elastic body” described in this section. In the embodiment of this section, not only one elastic body but also a plurality of elastic bodies may be provided. In addition, the “damper device” described in this section is not particularly limited in its specific structure, and may be, for example, a hydraulic type utilizing resistance to the flow of hydraulic fluid, Moreover, the electromagnetic type which depends on the force which an electromagnetic motor etc. generate | occur | produce may be used.

(5) The damper device includes a housing, a piston that divides the housing into two liquid chambers and is movable within the housing, and the flow of the working fluid between the two liquid chambers as the piston moves. It is a hydraulic damper device provided with a flow resistance imparting mechanism that imparts resistance to
One of the housing and the piston is connected to one of the sprung portion and the unsprung portion, and the other of the housing and the piston is connected to one end portion of the screw rod. Electromagnetic shock absorber for vehicles.

  The mode described in this section is a mode in which the structure of the damper device is specifically limited. When the threaded rod is connected to one of the sprung portion and the unsprung portion via the damper device having the structure described in this section, the piston is normally allowed to rotate in the housing. There is a possibility that the screw rod may rotate around the axis with respect to the other of the spring top and the spring bottom. Therefore, as described above, the screw rod rotation prohibiting device is suitable for the electromagnetic absorber having the damper device described in this section.

  (6) The electromagnetic shock absorber for a vehicle according to any one of (1) to (5), wherein one of the sprung portion and the unsprung portion is a sprung portion, and the other is a sprung portion.

  In the aspect described in this section, a screw rod is connected to a spring lower portion such as a suspension arm, and a nut is rotatably held on a spring upper portion which is a part of the vehicle body. According to the aspect of this section, since the electromagnetic motor is held at the upper part of the spring, for example, the electromagnetic motor can be effectively protected from water splash, mud splash, stone splash, etc., and transmitted from the lower part of the spring. Transmission of the generated vibration to the electromagnetic motor can be mitigated.

  Hereinafter, embodiments of the claimable invention will be described in detail with reference to the drawings. In addition to the following examples, the claimable invention includes various aspects in which various modifications and improvements have been made based on the knowledge of those skilled in the art, including the aspects described in the above [Aspect of the Invention] section. Can be implemented.

≪Configuration of electromagnetic absorber≫
FIG. 1 shows a shock absorber for a vehicle (hereinafter, may be abbreviated as “absorber”) 10 of an embodiment. For example, as shown in FIG. 2, the absorber 10 is installed in a vehicle as a component of the independent suspension system 20. The suspension device 20 shown in FIG. 2 is a multi-link suspension device, and includes a first upper arm 30, a second upper arm 32, a first lower arm 34, a second lower arm 36, and a toe control arm 38, each of which is a suspension arm. I have. One end of each of the five arms 30, 32, 34, 36, and 38 is rotatably connected to the vehicle body, and the other end is rotatable to an axle carrier 42 that rotatably holds the wheel 40. It is connected. With these five arms 30, 32, 34, 36, and 38, the axle carrier 42 can move up and down so as to draw a substantially constant trajectory with respect to the vehicle body.

  In the suspension device 20 configured as described above, the absorber 10 is arranged in parallel with the coil spring 50. Specifically, they are respectively parallel to each other between a mount portion 54 provided on a tire housing which is a component part of the spring upper part and a second lower arm 36 which is a component part of the spring lower part. It is arranged.

  As shown in FIG. 1, the absorber 10 includes a damping force generation unit 56 disposed between the mount portion 54 and the second lower arm 36. The damping force generation unit 56 is a main device for generating a damping force with respect to the relative motion of the sprung portion and the unsprung portion. The damping force generating unit 56 has a generally cylindrical housing tube 62 and an electromagnetic motor provided above the housing tube 62. 64. The housing tube 62 is fixedly connected at its upper end to a motor case 66 that houses the electromagnetic motor 64, and the motor case 66 is attached to the mount portion 54 via a buffer rubber at the outer periphery thereof. It is connected.

  The electromagnetic motor 64 includes a plurality of coils 70 that are fixedly arranged on one circumference along the inner surface of the peripheral wall of the motor case 66, and a cylindrical motor that is rotatably held by the motor case 66 and the housing tube 62. The shaft 72 includes a plurality of permanent magnets 74 fixed to the outer periphery of the motor shaft 72 so as to face the coil 70. The electromagnetic motor 64 is a three-phase DC brushless motor that includes a stator having a coil 70 and a rotor having a permanent magnet 74.

  The damping force generation unit 56 includes a screw rod 80 having a male thread formed on the outer peripheral portion thereof, and a nut 82 that holds the bearing ball and is screwed with the screw rod 80, and constitutes a ball screw mechanism. Yes. The screw rod 80 is disposed in the housing tube 62 so as to extend in the vertical direction while penetrating the motor shaft 72 of the electromagnetic motor 64. On the other hand, the nut 82 is fixedly fitted to the lower end portion of the motor shaft 72 while being screwed with the screw rod 80.

  The screw rod 80 is provided with an engagement hole 84 that opens to the upper end surface and extends in the axial direction of the screw rod 80 (corresponding to the axial direction of the absorber 10). On the other hand, an engagement rod 88 having a spline groove 86 formed in the outer peripheral portion is disposed in the motor case 66. The engagement rod 88 is fixed to the motor case 66 at the upper end, and is inserted into the engagement hole 84 of the screw rod 80 so as to extend in the axial direction in the motor shaft 72. As shown in FIG. 3, a cylindrical holder 90 is fixedly fitted in the engagement hole 84 of the screw rod 80 inside the upper end portion of the screw rod 80. The holder 90 is provided with ball circulation paths 92 at each of six circumferential positions in the circumferential direction, and the holder 90 holds the bearing balls 94 so that they circulate around the ball circulation paths 92. is doing. The engagement rod 88 is fitted into the holder 90, so that the engagement rod 88 and the screw rod 80 are spline-fitted. That is, the ball spline mechanism 96 is configured including the holder 90, the ball circulation path 92, the bearing ball 94, the spline groove 86, and the like, and the engagement rod 88 and the screw rod 80 cannot be relatively rotated by the mechanism 96. In addition, relative movement in the axial direction is possible. With such a structure, the screw rod 80 is allowed to move in the axial direction with respect to the sprung portion, but is not allowed to rotate around the axial line. That is, the damping force generation unit 56 includes a screw rod rotation prohibiting device 98 configured to include the engagement hole 84, the engagement rod 88, the ball spline mechanism 96, and the like.

  The screw rod 80 is fixed to the upper surface of a rod support member 100 having a generally covered cylindrical shape at the lower end. The rod support member 100 is elastically supported by two compression coil springs 102 and 104 in a state of being included in a substantially cylindrical damper cover 106 that covers a damper 105 described later. More specifically, the lower end portion of the rod support member 100 has a shape having a flange portion 108, and the spring 102 is sandwiched between the flange portion 108 and the upper end portion of the damper cover 106 in a compressed state, and the spring 104. Is sandwiched between the flange portion 108 and the lower end portion of the damper cover 106 in a compressed state. The rod support member 100 is elastically supported by the damper cover 106 by the elastic force of the springs 102 and 104. The damper cover 106 is fixed to the damper 105 at its lower end, specifically, to the outer periphery of a damper housing 120 (described later), which is a component of the damper cover 106, and the damper 105 is fixed to the lower end of the damper cover 106. The second lower arm 36 is connected via a mounting bush 110. That is, the screw rod 80, in other words, the damping force generating unit 56 is elastically supported on the lower part of the spring by the compression coil springs 102 and 104 as elastic bodies.

  The damper 105 is a damper device for generating a damping force with respect to relative movement between the screw rod 80 and the unsprung part. The damper 105 includes a generally cylindrical damper housing 120 that contains hydraulic fluid, a piston 122 that is fitted in the damper housing 120 in a liquid-tight and slidable manner therein, and a lower end connected to the piston 122. The piston rod 124 has an upper end portion that extends from above the damper housing 120. The damper housing 120 is fixedly fitted to the damper cover 106 so as to extend from the lower side thereof, and is connected to the second lower arm 36 via a mounting bush 110 at its lower end. The interior of the damper housing 120 is partitioned by the piston 122 into an upper chamber 126 that exists above it and a lower chamber 128 that exists below it. The piston rod 124 passes through a lid portion 129 provided on the upper portion of the damper housing 120, and is in sliding contact with the lid portion 129 through a seal. The upper end portion of the piston rod 124 is fixed to the lower surface of the lid portion of the rod support member 116.

  As shown in detail in FIG. 4, the damper housing 120 includes an outer cylinder 130 and an inner cylinder 132, and a buffer chamber 134 is formed between them. The piston 122 is fitted in the inner cylinder 132 so as to be liquid-tight and slidable. The piston 122 is provided with a plurality of connection passages 136 (two are shown in FIG. 4) that penetrate in the axial direction and connect the upper chamber 126 and the lower chamber 128. A circular valve plate 138 made of an elastic material is disposed on the lower surface of the piston 122 so as to be in contact with the lower surface, and the valve plate 138 blocks the opening on the lower chamber 128 side of the connection passage 136. It has a structure. The piston 122 is provided with a plurality of connection passages 140 (two shown in FIG. 4) at positions different from the connection passage 136 in the radial direction of the piston 122. A circular valve plate 142 made of an elastic material is disposed on the upper surface of the piston 122 so as to be in contact with the upper surface, and the opening on the upper chamber 126 side of the connection passage 140 is blocked by the valve plate 142. It has a structure. The connection passage 140 is provided on the outer peripheral side of the connection passage 136 and at a position away from the valve plate 138, and is always communicated with the lower chamber 128. Further, since the opening 144 is provided in the valve plate 142, the opening on the upper chamber 126 side of the connection passage 136 is not blocked, and the connection passage 136 is always in communication with the upper chamber 126. ing. Further, the lower chamber 128 and the buffer chamber 134 are in communication with each other, and a base valve body 146 provided with a connection passage and a valve plate similar to the piston 122 is provided between the lower chamber 128 and the buffer chamber 134. It has been.

  The absorber 10 is provided with a cover tube 150 so as to cover the damping force generation unit 56 and the damper cover 106. The cover tube 150 is fixed to the lower outer peripheral surface of the housing tube 62 at the upper end. Further, the cover tube 150 has the damper cover 106 inserted therein, and prevents dust and the like from entering the absorber 10.

  An annular lower retainer 152 is fixed to the lower end portion of the damper cover 106, and an annular upper retainer 154 is attached to the lower surface side of the mount portion 54 through vibration-proof rubber. The coil spring 50 is supported by the lower retainer 152 and the upper retainer 154 while being sandwiched between them. An annular buffer rubber 156 is attached to the lower end portion of the housing tube 62, and an annular buffer rubber 158 is attached to the lower end inner wall surface of the cover tube 150. An annular buffer rubber 160 is attached to the upper surface of the lid portion of the rod support member 100, and an annular buffer rubber 162 is attached to the lower surface of the lid portion of the rod support member 100.

  ≪Operation, function, control, etc. of electromagnetic absorber≫

  In the present absorber 10, when the spring top and the spring bottom move relative to each other, the screw rod 80 and the nut 82 move relative to each other, and the nut 82 rotates with respect to the screw rod 80. The electromagnetic motor 64 functions as a rotational force applying device that can apply a rotational force to the nut 82, and the damping force generation unit 56 generates a resistance force with respect to the relative movement between the spring top and the spring bottom by the rotational force. It is possible to make it. This resistance force becomes a damping force that attenuates the relative vibration between the sprung portion and the unsprung portion. That is, the damping force generation unit 56 generates a damping force with respect to the relative vibration between the spring upper part and the spring lower part depending on the motor force generated by the electromagnetic motor 64.

  The electromagnetic motor 64 is connected to a battery via an inverter as a drive circuit, and this inverter is connected to a control device. When this control device controls the inverter, the damping force generated by the damping force generation unit 56, that is, the relative vibration between the spring top and the spring bottom is attenuated. More specifically, a stroke sensor that detects a sprung unsprung distance is connected to the control device, and the control device determines whether the sprung portion or the unsprung portion is based on the sprung unsprung distance detected by the stroke sensor. A relative speed is calculated, and a damping force to be generated is calculated according to the relative speed. The control device issues a command based on the calculated damping force to the inverter, and the inverter controls the current flowing in the electromagnetic motor 64 by controlling a switching element included in the inverter. In this way, the damping force generation unit 56 generates a damping force to be generated.

  The damping force generating unit 56 relies on the motor force to make the spring upper part and the spring unsprung part approach and separate, and to maintain the distance between the spring upper part and the unsprung part at a predetermined distance, that is, as an actuator. It also has a function. By using this function, it is possible to effectively suppress the posture change of the vehicle body due to the roll of the vehicle body during turning, the pitch of the vehicle body during acceleration / deceleration, and the like.

  As described above, the damping force generation unit 56 generates an appropriate damping force by controlling the operation of the electromagnetic motor 64. However, when the frequency of relative vibration between the spring upper part and the spring lower part increases to some extent, the operation of the electromagnetic motor 64 does not follow due to factors such as control response of the electromagnetic motor 64. A sufficient attenuation effect cannot be obtained. In view of this, in this absorber 10, in order to effectively absorb high-frequency vibration, specifically, vibration in the unsprung resonance frequency range, for example, the damping force generating unit 56 is elastically disposed in the lower part of the spring. The above-described damper 105 is provided between them while being supported.

  When the damping force generation unit 56 and the unsprung part are separated from each other, the piston 122 is moved upward in the damper housing 120 in the damper 105, and a part of the hydraulic fluid in the upper chamber 126 passes through the connection passage 136. And a part of the hydraulic fluid in the buffer chamber 134 flows into the lower chamber 128 through the connection passage of the base valve body 146. At this time, the hydraulic fluid deflects the valve plate 138 and flows into the lower chamber 128, and the hydraulic fluid deflects the valve plate of the base valve body 146 and flows into the lower chamber 128. A resistance force is applied to the upward movement of, and a damping force for the movement is generated by the resistance force. Conversely, when the damping force generating unit 56 and the unsprung portion approach each other, the piston 122 is moved downward in the damper housing 120 so that a part of the hydraulic fluid in the lower chamber 128 is connected to the connection passage. It flows from the lower chamber 128 to the upper chamber 126 through 140 and flows out to the buffer chamber 134 through the connection passage of the base valve body 146. At this time, the hydraulic fluid deflects the valve plate 142 and flows into the upper chamber 126, and the hydraulic fluid deflects the valve plate of the base valve body 146 and flows into the buffer chamber 134, whereby the piston 122. A resistance force is applied to the downward movement of the lens, and a damping force for the movement is generated by the resistance force. That is, the damper 105 includes a flow resistance applying mechanism 148 including connection passages 136 and 140, valve plates 138 and 142, and the like, and depending on the mechanism 148, the damping force generation unit 56 and the unsprung part are provided. The structure is such that a damping force is generated with respect to the relative movement.

  When the spring upper portion and the spring lower portion are separated to some extent, the annular member 164 provided at the upper end portion of the damper cover 106 contacts the flange portion formed at the lower end portion of the cover tube 150 via the buffer rubber 158. Alternatively, the lower surface of the housing tube 62 comes into contact with the upper surface of the rod support member 100 via the buffer rubber 160. On the other hand, when the sprung portion and the unsprung portion approach each other to some extent, the annular member 164 contacts the lower surface of the housing tube 62 via the buffer rubber 156, or the upper surface of the lid portion 129 of the damper housing 120 is the buffer rubber 162. It is configured to contact the lower surface of the lid portion of the rod support member 100 via That is, the absorber 10 also has a stopper against approaching / separating between the vehicle body and the wheel, a so-called bound stopper, and a rebound stopper.

≪Features of electromagnetic absorber≫
In the absorber 10 of the above embodiment, the screw rod rotation prohibiting device 98 is provided using the engagement hole 84 provided in the screw rod 80, that is, the inside of the screw rod 80. Instead of the screw rod rotation prohibiting device 98, it is also possible to adopt a device having a structure that prohibits the rotation while allowing the screw rod to move in the axial direction on the outer periphery of the screw rod. FIG. 5A shows an absorber 170 provided with such a device as a comparative example.

  The absorber 170 shown in FIG. 5A includes a screw rod rotation prohibiting device 174 on the outer periphery of the screw rod 172. The screw rod rotation prohibiting device 174 has a substantially cylindrical rod holder 180 fixed to the lower surface of the housing tube 62, and the screw rod 172 passes through the rod holder 180. As shown in FIG. 6, the rod holder 180 is provided with a plurality of ball circulation paths 186, and the bearing balls 188 are held around the ball circulation paths 186. On the other hand, the screw rod 172 is provided with spline grooves 190 at positions facing each of the ball circulation paths 186, and the bearing balls 188 are fitted into the spline grooves 190. The screw rod rotation prohibiting device 174 has such a ball spline mechanism and prohibits the rotation of the screw rod 172 while allowing the screw rod 172 to move in the axial direction with respect to the sprung portion.

  FIG. 5B shows the absorber 10 of the above-described embodiment, and the absorber 10 has a shorter axial length than the absorber 170 of the comparative example. The length difference ΔL between the two absorbers 10 and 170 generally corresponds to the height dimension h of the rod holder 180. As described above, the absorber 10 is made compact. In other words, the expansion / contraction stroke of the absorber can be increased by the difference ΔL in length, so that the vibration damping function can be further improved.

It is sectional drawing which shows the electromagnetic shock absorber for vehicles which is an Example of claimable invention. It is a figure which shows the suspension apparatus by which the electromagnetic shock absorber for vehicles of FIG. 1 was arrange | positioned. It is a figure which shows the structure of the screw rod rotation prohibition apparatus with which the electromagnetic shock absorber for vehicles of FIG. 1 is provided. It is an expanded sectional view of the damper apparatus with which the electromagnetic shock absorber for vehicles of FIG. 1 is provided. FIG. 2 is a diagram illustrating the vehicle electromagnetic shock absorber of FIG. 1 and a vehicle electromagnetic shock absorber of a comparative example side by side. It is a figure which shows the structure of the screw rod rotation prohibition apparatus which the electromagnetic shock absorber of a comparative example has.

Explanation of symbols

  10: Electromagnetic shock absorber for vehicle 36: Second lower arm (lower part of spring) 54: Mount part (upper part of spring) 60: Damper (damper device) 64: Electromagnetic motor (rotational force applying device) 72: Motor shaft 80: Screw rod 82: Nut 84: Engagement hole 88: Engagement rod 96: Ball spline mechanism 98: Screw rod rotation prohibition device 102, 104: Compression coil spring (elastic body) 120: Damper housing 122: Piston 148: Distribution resistance applying mechanism

Claims (4)

(a) One end is connected to one of the spring upper part and the spring lower part, and a screw rod having a male screw formed on the outer periphery, and (b) the other of the spring upper part and the spring lower part is rotatably held. A nut formed and screwed with the screw rod; and (c) a rotational force applying device that has an electromagnetic motor and applies a rotational force to the nut based on a force generated by the electromagnetic motor, and a spring An electromagnetic shock absorber for a vehicle that generates a damping force for relative movement between an upper part and an unsprung part,
The screw rod has an engagement hole that opens in the end surface and extends in the axial direction at the other end that is the end opposite to the one end, and
The shock absorber
(A) the engagement hole; (B) an engagement rod fixed to the other of the spring upper part and the spring unsprung and fitted into the engagement hole; and (C) the engagement rod and the screw rod. And a mechanism that prohibits relative rotation of the screw rod in the axial direction while prohibiting relative rotation thereof, and allows movement of the screw rod in the axial direction relative to the other of the spring upper portion and the spring unsprung portion. An electromagnetic shock absorber for a vehicle comprising a screw rod rotation prohibiting device that prohibits rotation of the screw rod.   The screw rod rotation prohibiting device includes a mechanism for spline-fitting the engagement hole and the engagement rod as a mechanism for prohibiting the relative rotation while allowing the relative movement in the axial direction. The electromagnetic shock absorber for a vehicle according to claim 1.   2. The electromagnetic motor according to claim 1, wherein the electromagnetic motor has a generally cylindrical motor shaft, and one end portion of the motor shaft holds the nut and the screw shaft penetrates the motor shaft. Item 3. The electromagnetic shock absorber for a vehicle according to Item 2.   The shock absorber includes an elastic body that elastically connects one end of the screw rod and one of the spring top and the spring bottom, and the screw rod, the spring top, and the spring bottom arranged in parallel with the elastic body. The electromagnetic shock absorber for vehicles in any one of Claim 1 thru | or 3 provided with the damper apparatus which generate | occur | produces the damping force with respect to relative movement with one of these.

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