JP4942447B2 - Shock absorber - Google Patents

Description

  The present invention relates to an improved shock absorber.

This type of shock absorber includes a coil spring that elastically supports a vehicle body side member of a vehicle, a screw shaft that is rotatably engaged with a ball screw nut that is connected to the axle side member, and a pair of screws that are connected to one end of the screw shaft. And a hydraulic damper that is fixed to the vehicle body side member and damps vibrations in the vertical direction of the motor. The torque generated by the motor causes the vehicle body and the axle to There is one that actively controls the relative movement (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 08-197931 (paragraph number 0023, FIG. 1)

  However, the conventional shock absorber described above has problems in the following points.

  That is, in the shock absorber disclosed in Patent Document 1, when the screw is extended, the screw shaft is not prevented from coming off from the ball screw nut, and in the worst case, the screw shaft may fall off the ball screw nut. is there.

  In order to prevent the dropout, there is also a proposal to provide a stopper for restricting further lowering of the ball screw nut at the lowermost end of the screw shaft as in the shock absorber disclosed in JP-A-2004-11750. Until the stopper and the ball screw nut collide when the shock absorber is fully extended, the stroke in the extension direction of the shock absorber cannot be suppressed, and the extension of the shock absorber is caused by the collision between the stopper and the ball screw nut. It will be suddenly regulated.

  Therefore, even if a stopper is provided in the conventional shock absorber, since the extension is suddenly restricted, the shock due to the collision between the stopper and the ball screw nut is not alleviated before the shock, and the shock absorber makes a noise. May occur, or vibration due to the collision may be transmitted to the vehicle body side member, causing the vehicle occupant to feel uncomfortable, which may impair the riding comfort of the vehicle.

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

In order to achieve the above-described object, the problem-solving means of the present invention includes a hydraulic damper having an outer tube and a rod that is movably inserted into the outer tube, a linear motion member, and a drive source that drives the linear motion member. In a shock absorber formed by connecting a linear motion member to one end of a rod, a first spring receiver that is immovable in the expansion / contraction direction with respect to the rod and movable in the expansion / contraction direction with respect to the outer tube The second spring receiver is interposed between the first spring receiver and the second spring receiver, the second spring receiver, a regulating means that is provided in the middle of the outer tube and restricts the movement of the second spring receiver in the contraction direction. And an engaging portion that is immovable in the expansion and contraction direction with respect to the drive source and abuts against the second spring receiver when the predetermined extension occurs, and the engagement portion is connected to the drive source and is provided on the outer periphery of the outer tube. Through the seal member Characterized in that it eclipsed set in the middle of the sliding contact is the cylindrical body.

  According to the invention of each claim, this hydraulic damper is connected in series to the actuator and is disposed on the axle side member, so that the vehicle travels on a rough road or the road surface When high-frequency vibration such as vibration with relatively high acceleration is input to the axle side member when riding on a protrusion, for example, the vibration energy is absorbed, and the effect of suppressing vibration transmission by two springs is combined. Thus, it acts to make it difficult to transmit vibration to the actuator side connected to the vehicle body side member.

  That is, in this shock absorber, transmission of vibration to the vehicle body is suppressed when high-frequency vibration is input, so that there is no effect that the riding comfort in the vehicle is deteriorated, and at the same time, a spring accommodated in the hydraulic damper is provided. Since it functions as a rebound spring of the hydraulic damper and the impact at the time of the maximum extension of the hydraulic damper is alleviated, the riding comfort in the vehicle can be further improved, and the reliability of the hydraulic damper is also improved.

  Further, as described above, since the high-pressure vibration is prevented from directly acting on the actuator by the hydraulic damper, the transmission of the high-frequency vibration with particularly large acceleration to the motor is suppressed. The reliability of the actuator, which is the main component, is improved, and the reliability of the entire shock absorber can be improved in combination with the improvement of the reliability of the hydraulic damper.

  In addition, since a spring is provided to urge the hydraulic damper in the compressing direction and the extending direction, the high-frequency vibration of the axle side member is particularly suppressed from being transmitted to the actuator side, that is, the vehicle body side member. At the same time, it exerts the action of returning the piston to a predetermined position with respect to the cylinder of the hydraulic damper.

That is, it is possible to reduce the chance that the piston interferes with the cylinder, and in this respect as well, problems such as worsening the riding comfort in the vehicle and lowering the reliability of the shock absorber are eliminated.
Further, since the cylindrical body is slidably brought into contact with the outer periphery of the outer tube via the seal member, the main structural member of the hydraulic damper is disposed in the cylindrical body by the cylindrical body, and these main structural members are located outward. As a result, the main components are protected from water, stepping stones, and the like.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of a shock absorber according to an embodiment. FIG. 2 is a perspective view of the screw shaft with a ball screw nut and a ball spline nut attached thereto. FIG. 3 is a partially enlarged longitudinal sectional view of a shock absorber according to a modification of the embodiment.

  As shown in FIG. 1, the shock absorber D in one embodiment includes a hydraulic damper E having an outer tube 50 and a rod 34 that is movably inserted into the outer tube 50, a linear motion member, and a linear motion member. 1, an actuator A having a drive source for driving the rod 34, a first spring receiver 51 immovable in the up-and-down direction in FIG. 1 corresponding to the expansion / contraction direction with respect to the rod 34, and a vertical direction in FIG. A movable second spring receiver 52, a regulating means provided in the middle of the outer tube 35 for restricting the downward movement of FIG. 1 in the contraction direction of the second spring receiver 52, and the first spring receiver 51, A spring 53 interposed between the second spring receiver 52 and an engagement that does not move in the vertical direction in FIG. And comprising It has been.

  Hereinafter, each part of the shock absorber D will be described in detail. The actuator A includes a motion conversion mechanism H that converts the linear motion of the linear motion member into the rotational motion of the rotation member, and the drive source is coupled to the rotation member. It is referred to as a motor M. In the case of this embodiment, the motion conversion mechanism H includes a screw shaft 1 having a helical screw groove 2 on the outer peripheral side and a spline groove 3 along the axis, and a screw shaft 1 that is rotatably engaged with the screw shaft 1. A ball screw nut 4 that is a screw nut connected to the rotor R, and a ball spline nut 5 that has a plurality of balls that run in the spline groove 3 and that is non-rotatably connected to the stator S of the motor M. The actuator A can basically move the screw shaft 1 linearly in the vertical direction in FIG. 1 by rotationally driving the ball screw nut 4 with the torque generated by the motor M. .

  Further, when the screw shaft 1 is forcibly linearly moved by an external force, the rotor R of the motor M exhibits a rotational motion, and the motor M generates a torque that suppresses the rotational motion of the rotor R caused by the induced electromotive force. It functions to suppress the linear motion of the screw shaft 1. That is, in this case, the linear motion of the member on the linear motion side is suppressed by the regenerative torque generated by the motor M regenerating the kinetic energy input from the outside and converting it into electrical energy.

  That is, the shock absorber D can apply a thrust to the screw shaft 1 by positively generating a torque in the motor M, and when the screw shaft 1 is forcibly linearly moved by an external force, The linear motion of the screw shaft 1 can be suppressed by the regenerative torque generated by the motor M.

  Therefore, the shock absorber D not only generates a damping force that suppresses the linear motion of the screw shaft 1 but also functions as an actuator. Therefore, the shock absorber D functions as a vehicle body and an axle. In the case of being used in between, the posture control of the vehicle body of the vehicle can be performed at the same time, thereby functioning as an active suspension.

 Further, as shown in FIGS. 1 and 2, the screw shaft 1 is formed in a cylindrical shape, and a helical screw groove 2 is formed on the outer periphery thereof, and along the axis, that is, the screw shaft 1. A straight spline groove 3 is formed along the linear motion direction. The spline groove 3 may not be formed at the final ends on both sides of the screw shaft 1 in order to prevent the screw shaft 1 from dropping from a ball spline nut 5 described later. The number provided may be arbitrary.

  Since the ball screw nut 4 as a screw nut is well known and not shown in detail, a spiral passage facing the screw groove 2 of the screw shaft 1 provided on the inner periphery of the cylindrical main body and a cylindrical main body are provided. A circulation path that is provided and communicates with both ends of the passage, a plurality of balls that are accommodated in the passage and the circulation path and travel through the screw groove 2, and a spacer that is interposed between the balls. Each ball can circulate through the loop-shaped passage and the circulation path. A key groove 4 a is provided on the side of the ball screw nut 4.

  Subsequently, the ball spline nut 5 is also well-known and will not be shown in detail. However, this is also a linear passage facing the spline groove 3 of the screw shaft 1 provided on the inner periphery of the cylindrical body, and the cylinder. A circulation path that is provided in the main body and communicates with both ends of the passage, a plurality of balls that are accommodated in the passage and the circulation path, and run through the spline groove 3, and a spacer that is interposed between the balls. Each ball can circulate through the loop-shaped passage and the circulation path. A key groove 5 a is provided on the side of the ball spline nut 5.

  A ball screw nut 4 is screwed onto the screw shaft 1 along the screw groove 2, and a ball spline nut 5 is inserted along the spline groove 3 into the screw shaft 1.

  On the other hand, as shown in FIG. 1, the motor M includes a cylindrical casing 6, a core 7 that is an armature core fixed to the inner periphery of the casing 6, and a coil 8 that is fitted to the core 7. The stator S and the rotor R are rotatably held by the casing 6 via bearings 9, 10, and 11.

 The rotor R includes a cylindrical shaft 12 and a magnet 13 attached to the outer periphery of the shaft 12 so as to face the core 7. The upper end of the shaft 12 is pivoted by the inner periphery of the bearing 9 described above. The lower end is pivotally supported by the inner periphery of the bearings 10 and 11 and is housed and held in the casing 6. The magnet 13 is formed such that a plurality of magnets are bonded to each other so that N poles and S poles appear alternately along the circumference to form an annular shape, and an upper end is formed on a flange portion 12 a provided on the outer periphery of the shaft 12. The contact area is ensured by contacting. The magnet 13 may be an annular magnet having a divided magnetic pole pattern in which N poles and S poles appear alternately along the circumference.

  Therefore, in this embodiment, the motor M is configured as a brushless motor. However, various types of motors M can be used as the motor M. Specifically, for example, direct current, alternating current can be used. A motor, an induction motor, a synchronous motor, or the like can be used.

 A resolver core 14 is attached to the outer periphery of the upper end of the shaft 12 in the rotor R, and further, a resolver stator 15 is provided in the casing 6 and opposed to the resolver core 14, and the position of the rotor R is detected by these. The motor M can be controlled based on the position and rotational speed of the rotor R by a control device (not shown) that controls energization of the coil 8. The means for detecting the position of the rotor R may be a Hall element, a magnetic sensor, a rotary encoder, or the like other than the resolver described above.

  Further, the above-described ball screw nut 4 is housed and fixed inside the lower end of the shaft 12, and when the rotor R of the motor M is driven to rotate, the ball screw nut 4 can be rotated accordingly. In addition, a screw shaft 1 having a ball screw nut 4 screwed therein is inserted into the shaft 12. Specifically, the lower side of the portion of the shaft 12 where the magnet 13 is provided is enlarged to form an enlarged diameter portion 12b, and the ball screw nut 4 is accommodated in the enlarged diameter portion 12b and the expanded diameter portion 12b. The key 12d is inserted into the key groove 12c provided in the inner periphery of the diameter portion 12b and the key groove 4a provided in the ball screw nut 4, so that the ball screw nut 4 and the shaft 12 are prevented from being rotated and expanded. The ball screw nut 4 is fixed to the shaft 12 by an annular nut 12f screwed to a screw portion 12e provided on the inner periphery of the lower end of the diameter portion 12b.

  Further, a holder 16 that holds the outer periphery of the ball spline nut 5 is attached to the inner peripheral side of the lower end of the casing 6, and thereby the ball spline nut 5 is non-rotatably connected to the stator S of the motor M. Yes. Specifically, the holder 16 is formed in a bottomed cylindrical shape having an enlarged diameter on the upper side and provided with a stepped portion, and the outer peripheral side is press-fitted into the inner periphery of the casing 6 and fixed to the casing 6. A flange portion 16a that protrudes inward is formed on the inner peripheral side of the lower end, and a key groove 16b is provided on the inner periphery. Then, the ball spline nut 5 is accommodated in the inner periphery of the holder 16, and the key 16 c is inserted into the key groove 5 a provided on the side of the ball spline nut 5 and the key groove 16 b, so that the holder 16 of the ball spline nut 5 is The ball spline nut 5 is sandwiched between the snap ring 16d and the flange portion 16a which are attached to the inner periphery of the holder 16 and abut against the upper end of the ball spline nut 5 in FIG. The ball spline nut 5 is prevented from falling off the holder 16.

  Therefore, when the rotor R of the motor M is rotationally driven and the ball screw nut 4 exhibits a rotational motion, the screw shaft 1 is prevented from rotating by the ball spline nut 5 connected to the stator S of the motor M, so that the screw shaft. 1 exhibits a linear motion in the vertical direction in FIG.

  That is, in the shock absorber D, the screw shaft 1 is linearly moved, and the rotation preventing mechanism for the screw shaft 1 is constituted by a spline groove 3 and a ball spline nut 5 provided on the outer periphery of the screw shaft 1. Therefore, since the anti-rotation mechanism can be gathered around the screw shaft 1, it is possible to avoid an increase in the size of the anti-rotation mechanism and to reduce the outer diameter of the shock absorber D. The mountability of D on the vehicle is improved.

  Then, the ball screw nut 4 that is the driving portion of the screw shaft 1 and the ball spline nut 5 that is a component of the rotation prevention mechanism of the screw shaft 1 are disposed close to each other, so that the ball screw nut 4 and the ball spline nut 5 The length of the screw shaft 1 located in the section h can be shortened.

  The portion of the screw shaft 1 located in the section h is a portion where twisting occurs due to the rotational drive of the ball screw nut 4, and the shorter the section h, the shorter the portion where twisting occurs.

  Here, since the screw shaft 1 also functions as a spring element by torsion, the longer the torsional section h, the longer the response of the linear motion of the screw shaft 1 to the rotation of the ball screw nut 4 takes. However, as described above, the section h to which the screw shaft 1 is twisted can be shortened by disposing the ball screw nut 4 and the ball spline nut 5 close to each other, so that the response when the shock absorber D functions as an actuator. Will be improved.

  Therefore, since the responsiveness when the shock absorber D functions as an actuator is improved, the controllability when the vehicle attitude is actively controlled is also improved.

  Note that the ball screw nut 4 and the ball spline nut 5 are disposed close to each other for the convenience of providing members such as a nut 12f and a snap ring 16d necessary for fixing the ball screw nut 4 and the ball spline nut 5, and the ball For the purpose of compensating for the free rotation of the screw nut 4, the purpose is to arrange no unnecessary gap between the ball screw nut 4 and the ball spline nut 5 more than the gap that must be provided at the minimum.

  Further, since the ball screw nut 4 and the ball spline nut 5 are attached in series to the screw shaft 1, assuming that the ball screw nut 4 and the ball spline nut 5 do not fall off from the screw shaft 1, the screw shaft 1 is shown in FIG. When linearly moving in the middle and up and down directions, the length of the screw shaft 1 corresponding to the distance between the upper end in FIG. 1 of the ball screw nut 4 and the lower end in FIG. 1 of the ball spline nut 5 is the stroke of the linear motion of the screw shaft 1. Since the useless length does not contribute, as described above, the ball screw nut 4 and the ball spline nut 5 are arranged close to each other, whereby the upper end of the ball screw nut 4 in FIG. 1 and the lower end of the ball spline nut 5 in FIG. And the screw shaft 1 can be prevented from being unnecessarily lengthened, the overall length of the shock absorber D can be shortened, and the mountability of the shock absorber D on the vehicle can be further improved. With Ruru can be improved, it is possible to reduce the weight of the shock absorber D.

 Returning, the motor M is connected to the mount 20 so that it can be connected to the vehicle body side member of the vehicle. Specifically, the motor M is housed in a mount inner cylinder 21 connected to the holder 16, and the mount 20 is cylindrical with the mount inner cylinder 21, and is on the inner peripheral side at the upper end in FIG. And a chamber member 22 forming a chamber portion of the gas spring AS disposed on the outer peripheral side of the shock absorber D, an annular plate 23 connected to a vehicle body side member (not shown) of the vehicle, and a mount inner cylinder 21 And an anti-vibration rubber 24 that connects the chamber member 22 and an anti-vibration rubber 25 that connects the chamber member 22 and the plate 23.

  The gas spring AS functions as a suspension spring interposed between the vehicle body side member and the axle side member in the vehicle. The gas chamber a includes a chamber member 22 that forms a part of the mount 20. A cylindrical air piston 27 whose base end is coupled to the outer periphery of the lower end of a hydraulic damper E, which will be described later, and a diaphragm 28 fixed to the lower end of the chamber member 22 in FIG. 1 and the upper end of the air piston 27 in FIG. The cylindrical cover C is connected to the outer periphery of the lower end of the chamber member 22 and prevents the diaphragm 28 from expanding outward.

  Further, a valve 29 is provided at a side portion of the chamber member 22, and gas can be supplied into or discharged from the gas chamber a through the valve 29.

  Further, in the shock absorber D, as shown in FIG. 1, a rod 34 of a hydraulic damper E is connected to the lowermost end of the screw shaft 1 which is a linear motion member, and the actuator A and the hydraulic damper E are connected. Are connected in series. This hydraulic damper E is connected to a cylinder 30, a piston 33 that is slidably inserted into the cylinder 30 and separates the upper and lower pressure chambers 31 and 32 in the figure, and one end is connected to the piston 23. A rod 34 and an outer tube 35 functioning as a reservoir cylinder covering the outer peripheral side of the cylinder 20 are provided. Accordingly, in the hydraulic damper E, the rod 34 is movably inserted into the outer tube 35 and the two pressure chambers are formed in the outer tube 35.

  Hereinafter, the hydraulic damper E will be described in detail. A step (not shown) formed at the lower portion of the annular head member 36 is fitted into the upper end opening of the cylinder 30. The head member 36 is fitted inside the outer tube 35 and is fixed to the outer tube 35 by caulking the upper end opening of the outer tube 35. The head member 36 and the cylinder 30 are connected to the outer tube 35. 35 are positioned concentrically.

  A rod 34 is inserted into the inner peripheral side of the head member 36, and the head member 36 and the outer tube 35 are sealed between each other by a seal member 39 disposed on the outer peripheral side of the head member 36. A cylindrical bearing 38 that is in sliding contact with the outer periphery of the rod 34 disposed on the inner peripheral side thereof, and a seal member 37 that is also in sliding contact with the outer periphery of the rod 34 and seals between the rod 34 and the head member 36. The outer tube 35 and the upper end side of the cylinder 30 are sealed in a liquid-tight manner.

  On the other hand, the lower end of the outer tube 35 in FIG. 1 is closed by a bottom member 41 provided with an eye-shaped bracket 40 to which a hydraulic damper E can be attached to an axle side member of the vehicle. A disc-shaped valve body 42 is fitted, and the valve body 42 is sandwiched between the lower end of the cylinder 30 and the bottom member 41.

  Further, the valve body 42 includes a recess 42a on the lower end side, and the recess 42a communicates with a reservoir chamber 43 formed in a gap between the cylinder 30 and the outer tube 35 through a notch 42b. At the same time, it communicates with the lower pressure chamber 32 in FIG. 1 through passages 42c and 42d.

  Further, the upper end of the passage 42 c is closed by the check valve 44, and the lower end of the other passage 42 d is closed by the leaf valve 45.

  The piston 33 includes passages 46 and 47 that communicate the pressure chamber 31 and the pressure chamber 32, and a leaf valve 48 that closes the upper end of one passage 46 is stacked on the upper end of the piston 33. In addition, a leaf valve 49 that closes the lower end of the other passage 47 is stacked so that the leaf valves 48 and 49 provide resistance to the flow of liquid that passes through the passages 46 and 47, respectively.

  The pressure chambers 31 and 32 in the cylinder 30 are filled with liquid, and the reservoir chamber 43 formed by the gap between the cylinder 30 and the outer tube 35 is filled with a predetermined amount of liquid. Gas is enclosed.

  Accordingly, the hydraulic damper E is formed as a so-called double cylinder type. Of course, the hydraulic damper E may be formed as a so-called single cylinder type. However, as described above, the hydraulic damper E is a double cylinder type and the reservoir is arranged on the outer peripheral side of the cylinder. There is an advantage that the total length of the hydraulic damper E can be shortened. Note that when the hydraulic damper E is formed as a single cylinder type, it is not necessary to cover the cylinder with a reservoir cylinder, so that the cylinder functions as an outer tube.

  In the hydraulic damper E, when the rod 34 moves downward in FIG. 1 with respect to the cylinder 30, the piston 33 moves downward to expand the pressure chamber 31 and contract the pressure chamber 32.

  At this time, the liquid deflects the leaf valve 48 from the pressure chamber 32, passes through the passage 46 and moves to the pressure chamber 31, and the liquid of the rod intrusion volume into the cylinder 30 that is excessive in the cylinder 30 is retained. The leaf valve 45 is bent into the reservoir chamber 43 and moves through the passage 42d.

  The hydraulic damper E generates a damping force commensurate with the pressure loss that occurs when the liquid passes through the leaf valves 45 and 48.

  Conversely, when the rod 34 moves upward in FIG. 1 with respect to the cylinder 30, the piston 33 moves upward to expand the pressure chamber 32 and contract the pressure chamber 31.

  At this time, the liquid deflects the leaf valve 49 from the pressure chamber 31, passes through the passage 47 and moves to the pressure chamber 32, and the volume of the rod 34 that retreats from the cylinder 30 that is insufficient in the cylinder 30. The liquid deflects the check valve 44 from the reservoir chamber 43 and passes through the passage 42 c and moves into the cylinder 30.

  In this case, the hydraulic damper E generates a damping force commensurate with the pressure loss that occurs when the liquid passes through the leaf valve 49.

  In addition to the leaf valves 45, 48, and 49 described above, as a damping force generating element that generates a damping force in the hydraulic damper E, a throttle valve or other damping valve is used as long as it exhibits a predetermined damping action. It may be.

  Returning, the outer periphery of the outer tube 35 is provided with a cylindrical member 50 in which the intermediate portion bulges toward the outer periphery, and the cylindrical member 50 is stepped with the intermediate portion bulging outward. The part 50a is formed, and the above-described air piston 27 is attached to the lower end thereof. Further, a seal member 55 provided on the inner periphery of the lower end of the cylindrical body 26 attached to the outer periphery of the lower end in FIG. 1 of the mount inner cylinder 21 is in sliding contact with the outer periphery of the cylindrical member 50. Is sealed so that the pressure in the gas chamber a of the gas spring AS does not act on the screw shaft 1 covered with the cylindrical body 26, the seal member 37 of the hydraulic damper E, and thus the motor M. In the present embodiment, the gas spring AS is a suspension spring. However, the gas spring AS can be changed to a coil spring. Needless to say, the gas spring AS is a suspension spring. Even when the coil spring is a suspension spring, the cylinder 26 causes the motion conversion mechanism H in the actuator A and the main constituent members of the shock absorber D of the hydraulic damper E to be disposed in the cylinder 26. Since these main components are isolated from the outside of the shock absorber D, the main components are protected from water, stepping stones, and the like.

  Thus, in the shock absorber D, the screw shaft 1 and the hydraulic damper E are accommodated in the cylinder body 26 and the air piston 27, and the motor M is also accommodated in the mount inner cylinder 21. Since the main drive portion of the shock absorber D is isolated from the outside of the shock absorber D, it is possible to reliably prevent rainwater from entering the shock absorber D and contact of flying stones with the main drive portion. . Therefore, this improves the practicality of the shock absorber D.

  Subsequently, the upper end of the rod 34 is connected to the lower end of the screw shaft 1 described above. As is apparent from the above description, the screw shaft 1 is prevented from rotating by the ball spline nut 5, so that the rod 34 and the screw shaft 1 can be easily connected without being rotated. is there.

  That is, the motor M, the ball screw nut 4, the ball spline nut 5, and the screw shaft 1 that function as actuators and shock absorbers mainly by electromagnetic force are regarded as one assembly, and the hydraulic damper E side as one assembly. Can be easily manufactured.

  Further, since the screw shaft 1 is prevented from rotating by the ball spline nut 5, it is not necessary to provide a rotation stopper for the screw shaft 1 on the hydraulic damper E side, and therefore the rod 34 of the hydraulic damper E cannot be rotated. Since there is no need to specially process the rod 34 and the head member 36 or the bearing 37, it is sufficient to use a normal seal member instead of a special seal for the seal of the rod 34. The manufacturing cost of the shock absorber D is low.

  Returning, a first spring receiver 51 is interposed between the rod 34 and the screw shaft 1, and the first spring receiver 51 is connected to one end of the rod 34 so as to absorb the shock absorber D against the rod 34. It is assumed to be immovable in the vertical direction in FIG. The first spring receiver 51 includes an annular plate 51a, a cylindrical portion 51b suspended from the outer edge of the plate 51a, and a support portion 51c provided so as to protrude from the lower end in FIG. 1 toward the outer peripheral side of the cylindrical portion 51b. And is configured. Note that the inner diameter of the cylindrical portion 51b is set larger than the outer diameter of the outer tube 35 so that the outer tube 35 can enter.

  Furthermore, an annular second spring receiver 52 that is opposed to the first spring receiver 51 and that is in sliding contact with the outer periphery of the outer tube 35 is provided. The second spring receiver 52 includes an annular plate 52a, A cylindrical guide portion 52b rising from the inner edge of the plate 52a, and the guide portion 52b slides in contact with the upper outer periphery of the outer tube 35 and moves up and down in FIG. Is allowed.

  Further, the vertical length of the guide portion 52b that is in sliding contact with the outer periphery of the outer tube 35 does not hinder the movement of the second spring receiver 52 relative to the outer tube 35, and may tilt and bite the outer periphery of the outer tube 35. Since the length is such that it does not exist, the second spring receiver 52 can move smoothly in the vertical direction in FIG.

  The second spring receiver 52 is restricted from moving downward in FIG. 1 in the direction of contraction of the shock absorber D from the step portion 50a by a step portion 50a formed by expanding the middle of the cylindrical member 50. Has been. That is, the movement of the second spring receiver 52 is restricted by a step portion 50a provided in the middle of the outer tube 35, and in the present embodiment, the restriction means is the step portion 50a. The restricting means is not necessarily configured as described above, and the second spring receiver 52 is located at a position in the middle of the outer tube 35 where it is desired to restrict the downward movement of the second spring receiver 52. It is possible to provide a flange, a flange, a projection, or the like that can prevent the downward movement in FIG. 1 as the contraction direction of the second spring. The movement of the receptacle 52 may be restricted.

  Here, in order to attach the cylindrical member 50 to the outer periphery of the outer tube 35, the upper end of the cylindrical member 50 is brought into contact with a stepped portion 35 a formed in the middle of the outer tube 35 so that the outer periphery has a small diameter. What is necessary is just to weld a lower end and the lower end of the outer tube 35. By attaching the cylindrical member 50 to the outer periphery of the outer tube 35 in this way, welding distortion does not occur in the middle of the outer tube 35, and the outer tube There is an advantage that the strength of 35 is not unnecessarily lowered. Therefore, the formation of the restricting means by the stepped portion 50a of the cylindrical member 50 makes it very easy to process the outer tube 35 as compared with the provision of the restricting means by other methods. This is advantageous in that it does not affect

  Subsequently, a spring 53 is interposed between the support portion 51 c of the first spring receiver 51 and the plate 52 a of the second spring receiver 52, and the second spring receiver 52 is connected to the spring 53. The rod 34 protrudes from the outer tube 35 in a state where it is in contact with the stepped portion 50a and is positioned in the middle of the outer tube 35 and further downward movement in FIG. In this direction, that is, in a direction in which the hydraulic damper E is extended.

  Further, between the plate 52a of the second spring receiver 52 and the spring 53, an annular plate 52c is interposed as an allowable means for allowing the rotation of the spring 53 with respect to the spring receiver 52 in the circumferential direction. By means of the annular plate 52c as means, torque due to rotation of the spring 53 during expansion and contraction is prevented from being transmitted to the first spring receiver 51, and the rod 34 and the screw shaft 1 are connected by screwing. In addition, the connection between the rod 34 and the screw shaft 1 is prevented from being broken. Therefore, even if the spring 53 is arranged as described above, the rod 34 and the screw shaft 1 can be connected by screwing.

  In addition, since the torque from the spring 53 does not act on the first spring receiver 51 and the second spring receiver 52, an unnecessary frictional force is not generated on the first spring receiver 51 and the second spring receiver 52. In addition to not hindering the smooth expansion and contraction of the shock absorber D, it is possible to prevent the first spring receiver 51 and the second spring receiver 52 from deteriorating.

  Subsequently, the plate 52a of the second spring receiver 52 described above has a larger diameter than the outer diameter of the stepped portion 50a, and when the shock absorber D extends to a predetermined length, that is, when the shock absorber D extends a predetermined length, The lower end of the plate 52 a comes into contact with the cushion member 56 stacked on the upper end of the seal member 55 of the cylindrical body 26.

  More specifically, when the shock absorber D extends, the cylindrical body 26 is connected to the motor M that is the drive source of the actuator A via the mount inner cylinder 21 and extends in the vertical direction in FIG. Since it does not move, it moves upward in FIG. 1 with respect to the outer tube 35 of the hydraulic damper E, and the cushion member 56 is in the contraction direction of the shock absorber D with respect to the cylindrical body 26 by the seal member 55. Since the downward movement in FIG. 1 is restricted, the cushion member 56 comes into contact with the lower end of the plate 52 a of the second spring receiver 52. Therefore, in the present embodiment, the engaging portion that does not move in the expansion / contraction direction of the shock absorber D with respect to the motor M that is the driving source and contacts the second spring receiver 52 when the shock absorber D is extended a predetermined time. If there is no problem, the cushion member 56 is discarded, and the upper end of the seal member 55 is brought into direct contact with the second spring receiver 52, and the upper end of the seal member 55 is used as the engaging portion. Further, as shown in FIG. 3, a step portion 26a is formed from the middle of the cylindrical body 26 with the lower end side as a succession, and the step portion 26a is used as an engaging portion to form a second spring. You may make it contact | abut to the lower end of the receptacle 52. FIG. In other words, the engaging portion only needs to be immovable in the expansion / contraction direction of the shock absorber D with respect to the motor M as a driving source, and be able to come into contact with the second spring receiver 52 when the shock absorber D is extended a predetermined time.

  As described above, when the shock absorber D further extends from the state in which the cushion member 56 and the second spring receiver 52 are in contact with each other, the cylindrical body 26 also moves upward in FIG. 1 with respect to the outer tube 35. Therefore, the second spring receiver 52 is also moved upward, and the spring 53 is compressed.

  That is, when the shock absorber D is extended to a predetermined extent, the second spring support 52 comes into contact with the cushion member 56 whose downward movement with respect to the cylindrical body 26 is restricted by the seal member 55, and further expansion of the shock absorber D is prevented. Thus, the spring 53 exerts an urging force that suppresses the extension.

  That is, the spring 53 functions as a rebound spring for the entire extension of the shock absorber D, and reduces the extension speed of the shock absorber D until the shock absorber D reaches the maximum extension from the predetermined extension time. The shock at the time of the maximum extension of the shock absorber D can be alleviated, and the riding comfort in the vehicle can be improved.

  When the spring 53 is in the most compressed state, the shock absorber D becomes unable to extend any more and restricts the length of the shock absorber D when it is fully extended, so that the screw shaft 10 is connected to the ball screw nut 13 or the like. It is also possible to prevent a situation where the ball spline nut 14 falls off.

  Furthermore, even if the motor M, which is the drive source of the actuator A, cannot generate torque for some reason and the expansion of the shock absorber D cannot be suppressed, at least from the predetermined expansion time by the spring 53. The expansion can be suppressed until reaching the most compressed state, and the shock at the time of the maximum expansion of the shock absorber D can be reduced.

  As described above, even when the shock absorber D is in the maximum extension state, the packing 55a on the upper side of the seal member 55 is not positioned above the step portion 50a of the cylindrical member 50 in FIG. Of course, the packing 55a is prevented from falling off.

  In turn, a second spring 54 accommodated in the hydraulic damper E is interposed between the head member 36 and the piston 33, and the second spring 54 is accommodated in the hydraulic damper E. Since the piston 33 is urged in the direction in which the hydraulic damper E contracts, it functions as a rebound spring that alleviates the impact caused by the interference between the head member 36 and the piston 33 when the hydraulic damper E is extended to the maximum. To do.

  Further, the spring 53 and the second spring 54 are both balanced with an initial load applied and compressed, and the piston 33 is positioned at the neutral position by the spring 53 and the second spring 54. The neutral position of the piston 33 is a position that is positioned by the spring 53 and the second spring 54. The neutral position is not necessarily set at the center position of the cylinder 30 in the vertical direction in FIG. Also good.

  Resin-made spring holders 54a and 54b are attached to both ends of the second spring 54, and the second spring 54 is prevented from directly interfering with the piston 33 and the head member 36. The piston 33 and the head member 36 are prevented from being damaged.

  The spring 53 and the second spring 54 function to suppress transmission of high-frequency vibration of the vehicle axle side member to the motor M side, that is, the vehicle body side member, and at the same time to the cylinder 30 of the hydraulic damper E. In contrast, the piston 33 is returned to a predetermined position. That is, since the piston 33 is returned to a predetermined position with respect to the cylinder 30, even if a high frequency vibration that pushes up from the road surface is input, a situation in which the piston 33 collides violently with the valve body 42 is prevented. Therefore, the riding comfort in the vehicle is not deteriorated, and the reliability of the shock absorber D is not lowered. In this way, the second spring 54 urges the hydraulic damper E in the contracting direction, and the spring 53 is restricted from moving downward by the first spring receiver 51 provided at one end of the rod 34 and the restricting means. By being interposed between the second spring receiver 52, the spring 53 not only functions as a rebound spring for the entire shock absorber D, but also positions the piston 33 of the hydraulic damper E at the neutral position. In addition to the spring 53, it is not necessary to separately provide a spring for positioning the piston 33 in the neutral position, and the number of parts can be reduced and the cost of the shock absorber D can be avoided. it can.

  When the hydraulic damper E is in the maximum extension state, the second spring 54 is in the maximum compression state and restricts further extension of the hydraulic damper E. In this state, when the shock absorber D is extended to the maximum, the second spring receiver 52 abuts on the cushion member 56 as an engaging portion and moves upward in FIG. 1 to bring the spring 53 into the most compressed state. When the spring 53 is in the most compressed state, the second spring receiver 52 is set to be positioned at least on the lower side on the side opposite to the rod side from the upper end on the rod side end of the outer tube 35.

  That is, by setting in this way, even when the hydraulic damper E is extended to the maximum and the shock absorber D is extended to the maximum, the second spring receiver 52 is connected to the rod of the outer tube 35. Since the upper end as the side end is prevented from coming out upward in FIG. 1, the reliability of the shock absorber D is improved.

  As long as the above setting is satisfied, the shape of the first spring receiver 51 is not limited to the shape described above.

  In the shock absorber D in this embodiment, the hydraulic damper E is connected in series to the screw shaft 1 that linearly moves by the motor M, and is disposed on the axle side member. Therefore, when high-frequency vibration such as vibration with relatively high acceleration is input to the axle-side member when the vehicle travels on a rough road or rides on a protrusion on the road surface, this vibration energy In combination with the above-described vibration transmission suppressing effect by the urging means, it acts to make it difficult to transmit vibration to the screw shaft 1 side.

  Here, in the shock absorber D, vibration that is linear motion input from the axle-side member is converted into rotational motion. However, the shock absorber D includes many rotating members and has a large inertial mass and a high frequency. Although there is a characteristic that the moment of inertia increases with respect to vibration and the influence of friction causes the vibration of the axle side member to be easily transmitted to the vehicle body side member, as described above, the hydraulic damper E Absorbs the vibration, and further, the spring 53 and the second spring 54 exhibit the vibration transmission suppressing effect, thereby suppressing the transmission of vibration to the screw shaft 1. Even in such a case, there is an effect that the riding comfort in the vehicle is not deteriorated, and at the same time, the second spring 54 also functions as a rebound spring of the hydraulic damper E, so Elongation Since also the impact is relaxed, and more able to further improve the ride comfort in the vehicle is also improved reliability of the hydraulic damper E.

  Further, since the hydraulic damper prevents the high-frequency vibration from directly acting on the motor M and the ball screw nut 4, the high-frequency vibration having particularly high acceleration is transmitted to the motor M and the ball screw nut 4. Therefore, the reliability of the actuator A, which is the main component of the shock absorber D, is improved, and the reliability of the entire shock absorber D can be improved together with the reliability of the hydraulic damper E.

  In addition, since the use environment of the actuator A can be improved by adopting the above configuration, the cost of the actuator A can be reduced.

  Further, since the linear motion of the actuator A is transmitted to the hydraulic damper E, that is, the actuator A is connected to the vehicle body side member, the mass supported by the springs 53 and 54 is a motor. Those having a large mass such as M are not included.

  Therefore, even if high-frequency vibration acts on the axle side member, the conventional shock absorber in which the motor M itself is supported by the spring is supported by the springs 53 and 54 and vibrates between the vehicle body side member and the axle side member. Therefore, it is difficult to transmit the vibration of the axle-side member to the vehicle body-side member, which makes it possible to further improve the riding comfort.

  Further, as apparent from the above, since the motor M itself is not supported by the spring 53 and the second spring 54, the wiring of the motor M and the like can be easily arranged, and high-frequency vibration is directly applied to the motor M itself. Since it is not input, there is no worry of damaging the wiring. Therefore, the mountability of the shock absorber D on the vehicle is improved and is more practical.

  Note that the configuration of the motion conversion mechanism H in the actuator A is such that the screw shaft 1 is linearly moved in the vertical direction. Instead, the screw shaft is connected to the rotor R of the motor M or the shaft of the rotor R is replaced. And the ball screw nut 4 may be linearly moved in the vertical direction by the rotational motion of the screw shaft 1, and this linear motion may be transmitted to the hydraulic damper E. In this case, it is necessary to provide a separate stopper for the ball screw nut 4, but the ball screw nut 4 and the rod 34 of the hydraulic damper E or the cylinder 30 may be connected.

  Furthermore, the motion conversion mechanism H may be configured by a mechanism such as a rack and pinion or a worm gear other than the above.

  In addition, in the above description, the ball screw nut 4 is attached to the shaft 12 of the rotor R, but the ball screw nut 4 itself is used as the shaft in the rotor R of the motor M so that the magnet 13 is attached to the outer periphery of the ball screw nut 4. It may be.

  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 shock absorber in one embodiment. It is a perspective view in the state where a ball screw nut and a ball spline nut were attached to the screw shaft. It is a partially expanded longitudinal cross-sectional view of the shock absorber in one modification of one embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Screw shaft 2 Screw groove 3 Spline groove 4 Ball screw nut 4a, 5a, 12c, 16b which is a screw nut Key groove 5 Ball spline nut 6 Casing 7 Core 8 Coil 9, 10, 11, 38 Bearing 12 Shaft 12a, 16a Flange part 12b Expanded diameter portion 12d, 16c, 26a Key 12e Screw portion 12f Nut 13 Magnet 14 Resolver core 15 Resolver stator 16 Holder 16d Snap ring 20 Mount 21 Mount inner cylinder 22 Chamber member 23 Plates 24, 25 Anti-vibration rubber 26 Cylindrical body 26a Engagement Step portion 27 Air piston 28 Diaphragm 29 Valve 30 Cylinder 31, 32 Pressure chamber 33 Piston 34 Rod 35 Outer tube 35a Step portion 36 Head member 37, 39, 55 Seal member 40 Eye bracket 41 Bottom Material 42 Valve body 42a Recess 42b Notches 42c, 42d, 46, 47 Passage 43 Reservoir chamber 44 Check valve 45, 48, 49 Leaf valve 50 Cylindrical member 50a Step portion 51 as regulating means First spring receiver 51a Plate 51b Cylindrical portion 51c Bearing portion 52 Second spring support 52a Plate 52b Guide portion 52c Annular plate 53 Spring 54 Second spring 55 Seal member 55a Packing 56 Cushion member A Actuator AS Gas spring a Gas chamber C Cover D Buffer E Hydraulic damper h Section M between ball screw nut and ball spline nut Motor R Rotor S Stator

Claims (7)

A hydraulic damper having an outer tube and a rod that is movably inserted into the outer tube; and an actuator having a linear motion member and a drive source for driving the linear motion member. In the shock absorber formed by coupling, a first spring receiver that is immovable in the expansion / contraction direction with respect to the rod, a second spring receiver that is movable in the expansion / contraction direction with respect to the outer tube, and a second spring receiver that is provided in the middle of the outer tube. The spring means is restricted in the contraction direction, the spring interposed between the first spring receiver and the second spring receiver, and a contacting engagement portion to receive a second spring when a predetermined elongation, the engaging portion is set in the middle of the cylindrical body is in sliding contact with a sealing member on the outer periphery of the connection has been outer tube to the drive source Relaxed, characterized by Vessel. The first spring receiver is connected to one end of the rod, and the second spring receiver is slidably fitted to the outer periphery of the outer tube. When the spring is in the most compressed state, the second spring receiver is The shock absorber according to claim 1, wherein the shock absorber is set so as to be positioned on the side opposite to the rod side end from the rod side end of the tube. A cylindrical member is provided on the outer periphery of the outer tube so that the intermediate portion bulges toward the outer periphery, and a regulating means including a step portion bulged outward is formed in the intermediate portion of the cylindrical member. The shock absorber according to claim 1 or 2, wherein a seal member provided on the inner periphery of the lower end of the cylinder is slidably contacted on the outer periphery . The hydraulic damper includes a piston connected to a rod, which separates two pressure chambers in the outer tube, and a second spring that urges the hydraulic damper in a contracting direction. The shock absorber according to any one of claims 1 to 3, wherein the piston is positioned at a neutral position by a spring and a second spring interposed between the first spring receiver and the second spring receiver. 5. The actuator according to claim 1, wherein the actuator includes a motion conversion mechanism that converts linear motion of the linear motion member into rotational motion of the rotating member, and the drive source is a motor coupled to the rotating member. The shock absorber described. 6. The shock absorber according to claim 5, wherein the motion conversion mechanism is a screw shaft connected to a motor, and a screw nut connected to the rod and screwed rotatably to the screw shaft. The motion conversion mechanism includes a screw shaft having a helical screw groove on the outer peripheral side and a spline groove along the axis, a screw nut that is rotatably engaged with the screw shaft and connected to a rotor of the motor, and an inner portion of the spline groove. The shock absorber according to claim 5, further comprising a ball spline nut that has a plurality of balls that run on the motor and is non-rotatably connected to a stator of the motor.

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