JP2007290639A - Shock absorber - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a shock absorber capable of enhancing reliability and ride comfort in a vehicle while adopting a constitution for generating attenuation force utilizing electro-magnetic force of a motor. <P>SOLUTION: The shock absorber is provided with an actuator A provided with a motion conversion mechanism T and the motor M and connected to a springing member B side of the vehicle; a hydraulic damper E provided with a cylinder C, a piston P slidably inserted in the cylinder C and partitioning two pressure chambers in the cylinder C and a rod R having one end connected to the piston P in which linear motion of the actuator A is transmitted to one of the rod R or the cylinder C and the other of the rod R or the cylinder C is connected to a sprung member W side of the vehicle; a spring 1 stored in the one pressure chamber 35 and urging the hydraulic damper E in a compression direction; and a spring 2 stored in the other pressure chamber 36 and urging the hydraulic damper E in a stretching direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an improvement of a shock absorber that suppresses relative movement between the vehicle body and an axle by electromagnetic force generated in a motor.

  As this kind of shock absorber, there is a proposal of a shock absorber provided with a hydraulic damper and an actuator for giving a propulsive force to the piston rod of the hydraulic damper. In this proposal, the rod of the hydraulic damper is formed in a cylindrical shape and the rod A female screw part is provided on the inner peripheral side, one end is connected to the rotor of the motor, and the other end is connected to a male screw member screwed to the female screw part of the rod, and the shaft of the hydraulic damper is inserted through the shaft. And the rod constitutes a piston rod of a hydraulic damper (for example, see Patent Document 1).

  In this proposal, the damping force generated by the hydraulic damper is added to the force generated when the shaft and rod are moved relative to each other in the axial direction by the motor to expand and contract the piston rod. By converting it into a force in the direction of relative movement with the rod, the force is additionally applied to the damping force of the hydraulic damper to attenuate the vibration.

Also, a coil spring that elastically supports the vehicle body side, that is, the sprung member side of the vehicle, a screw shaft that is rotatably engaged with a ball screw nut that is connected to the axle, that is, the unsprung member side, and one end of the screw shaft. And a motor that is interposed between a pair of springs and elastically supported on the sprung member side, and a hydraulic damper that is fixed on the vehicle body side and attenuates vibrations in the vertical direction of the motor. There is one that actively controls the relative movement between the vehicle and the axle (for example, see Patent Document 2).
JP 2001-180244 A (paragraph numbers 0019 to 0021, FIG. 2) 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 of Patent Document 1, since the piston rod is forcibly extended by the motor, it is not certain what position the piston position of the hydraulic damper is relative to the cylinder.

  As a result, for example, if there is a high-frequency vibration that pushes up from the road surface with the piston positioned near the lower end of the cylinder, the piston collides with the base valve or the cylinder bottom. As a result, the impact due to the collision may be transmitted to the sprung member of the vehicle body, which may impair the riding comfort in the vehicle, or in the worst case, may damage the hydraulic damper.

  In addition, if the piston is positioned near the upper end of the cylinder, this may cause the piston to collide with the upper part of the cylinder when the vehicle body is bumped. In addition, the hydraulic damper is damaged, and there is a problem in terms of the reliability of the shock absorber.

  Also, when the position of the piston with respect to the cylinder is constantly monitored and the piston is controlled so as to be in the neutral position, the piston rod is expanded and contracted while the vehicle is running, although it is not necessary for posture control. The vehicle body posture will change, which will cause anxiety and discomfort to the vehicle operator, so it will not improve the ride comfort in the vehicle. is there.

  Subsequently, in the shock absorber of Patent Document 2, since the motor is centered through a pair of springs, the piston of the hydraulic damper is positioned with respect to the cylinder. It will be resolved.

  This shock absorber is provided with a motion conversion mechanism composed of a screw shaft and a ball screw nut that converts a torque of a motor that is a damping force generation source into a damping force that should act in a linear direction, and the inertia of the rotating member Since the mass of the motor and the motion converting mechanism cannot be expanded and contracted due to the friction of the rotating system when the high frequency vibration is input due to the large mass, the high frequency vibration is absorbed by the hydraulic damper and the pair of springs.

  However, in this shock absorber, as described above, when high-frequency vibration is input, the motor is directly vibrated by the high-frequency vibration, and the high-frequency vibration has a large acceleration, so the reliability of the shock absorber is high. There is a problem in terms.

  Further, since the motor and the screw shaft are large in mass, the motor and the screw shaft are vibrated greatly in the configuration in which the motor and the screw shaft are elastically supported by the pair of springs. Riding comfort can be worse in that it is easier to communicate with the car.

  Therefore, the present invention was created in consideration of the above-described problems, and the object of the present invention is to provide reliability and vehicle while adopting a configuration that generates a damping force using the electromagnetic force of a motor. It is providing the shock absorber which can improve the ride comfort in.

  In order to achieve the above object, an actuator connected to the sprung member side of the vehicle, comprising a motion conversion mechanism for converting linear motion into rotational motion and a motor to which the rotational motion converted by the motion conversion mechanism is transmitted. The cylinder includes a piston that is slidably inserted into the cylinder and that separates the two pressure chambers in the cylinder, and a rod having one end connected to the piston, and the linear motion of the actuator is transmitted to one of the rod or the cylinder. In addition, a hydraulic damper in which the other of the rod or cylinder is connected to the unsprung member side of the vehicle, a spring that is housed in one of the pressure chambers and urges the hydraulic damper in a compressing direction, and the other And a spring which is housed in the pressure chamber and urges in a direction to extend the hydraulic damper.

  According to the invention of each claim, since the hydraulic damper is connected in series to the actuator and is disposed on the unsprung member side, 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 unsprung member when riding on the protrusions of this, for example, the vibration energy is absorbed, and the vibration transmission suppressing effect by the pair of springs is combined. As a result, it acts to make it difficult to transmit vibration to the actuator side.

  Therefore, the hydraulic damper absorbs the vibration, and further, each spring exerts a vibration transmission suppressing effect, thereby suppressing the transmission of vibration to the actuator. Even in this case, there is an effect that the ride comfort in the vehicle is not deteriorated.

  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 shock absorber can be improved by eliminating the problems of the conventional shock absorber.

  In addition, since a spring that urges the hydraulic damper in a compressing direction and a spring that urges the hydraulic damper in an extending direction are provided, particularly high-frequency vibrations of the unsprung member are caused on the actuator side, that is, on the spring. It acts to suppress transmission to the member side, and at the same time exerts the action of returning the piston to a predetermined position with respect to the cylinder of the hydraulic damper.

  That is, the problem that the piston interferes with the cylinder and deteriorates the riding comfort in the vehicle, and the reliability of the shock absorber is reduced, as in the conventional shock absorber.

  Since each spring is housed in the cylinder of the hydraulic damper, the shock absorber can be made slimmer and smaller than a configuration in which a spring receiver and each spring are provided on the outer periphery of the hydraulic damper. In addition, since the diameter of each spring can be reduced, the same spring constant can be ensured even if the wire rod diameter is reduced compared to the case where each spring is provided on the outer peripheral side of the hydraulic damper. Therefore, the cost of each spring can be reduced and the shock absorber can be reduced in weight.

  In addition, since it is not necessary to provide a spring receiver and each spring on the outer periphery of the hydraulic damper, the outer diameter of the hydraulic damper can be increased accordingly. Therefore, it is possible to prevent the change in the damping force characteristic of the hydraulic damper by suppressing the temperature change of the liquid.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a diagram conceptually showing a shock absorber according to the present invention. FIG. 2 is a longitudinal sectional view of a shock absorber as an example of a specific configuration. FIG. 3 is an enlarged longitudinal sectional view of a hydraulic damper portion in a shock absorber which is an example of a specific configuration.

  As shown in FIG. 1, the shock absorber D is interposed between the unsprung member W and the sprung member B in parallel with the suspension spring S, and is basically connected to the unsprung member W. A hydraulic damper E, an actuator A connected in series to the hydraulic damper E and connected to the sprung member B, and an actuator A and an unsprung member W are interposed in parallel with the hydraulic damper E. The spring 1 is biased in the direction of compressing the hydraulic damper E, and the spring 2 is biased in the direction of extending the hydraulic damper E.

  The actuator A includes a motion conversion mechanism T that converts linear motion into rotational motion, and a motor M to which the rotary motion converted by the motion conversion mechanism T is transmitted. Specifically, for example, a feed screw mechanism composed of a screw shaft and a screw nut, a mechanism such as a rack and pinion, a worm gear, and the like are included.

  In the case of this actuator A, since the drive source is the motor M, when the rotation member in the motion conversion mechanism T, that is, when the feed screw mechanism is adopted, either the screw shaft or the screw nut is rotated. When the motor M is driven by applying electrical energy, the member on the linear motion side is linearly moved, that is, the function as an actuator can be exhibited.

  In addition, when the motor M is forcibly input from the rotating member side, the motor M generates a torque that suppresses the rotating motion of the rotating member based on the induced electromotive force. Therefore, the linear motion of the member on the linear motion side is generated. It functions to suppress. 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.

  Therefore, the actuator A can apply a thrust to the member on the linear motion side by positively generating a torque in the motor M, and when the member on the linear motion side is forcibly moved by an external force. Can suppress the above-described movement by the regenerative torque generated by the motor M.

  In this shock absorber D, the relative movement between the sprung member B and the unsprung member W can be suppressed by the thrust and torque generated by the actuator A, and at the same time, the function as an actuator can be utilized. The posture control of the sprung member B, specifically, the vehicle body of the vehicle can be performed at the same time, whereby the function as an active suspension can be exhibited.

  Since the motor M and the rotation member of the motion conversion mechanism T need only be connected so as to be able to transmit rotational motion, a reduction gear or rotational motion can be transmitted between the motor M and the rotational member. A simple link, joint or the like may be interposed.

  The motor M may be any type as long as it can realize the above-described functions. Specifically, for example, a DC, AC motor, induction motor, synchronous motor, or the like is used. Can do.

  In turn, the hydraulic damper E will be described in detail later, but a cylinder C, a piston P that is slidably inserted into the cylinder C and separates two pressure chambers in the cylinder C, and a piston P And a rod R having one end connected thereto, and generates a predetermined damping force during expansion and contraction.

  In this shock absorber, the hydraulic damper E is interposed between the actuator A and the unsprung member W mainly for the purpose of absorbing high-frequency vibrations. Specifically, one end is a member on the linear motion side of the actuator A. The other end is connected to the unsprung member W.

  In connecting the hydraulic damper E and the actuator A, one of the cylinder C or the rod R of the hydraulic damper E may be connected to a member on the linear motion side of the actuator A, while The other of the cylinder C or the rod R of the hydraulic damper E is connected.

  Therefore, the hydraulic damper E may be interposed between the actuator A and the unsprung member W in a so-called upright manner or in an inverted manner.

  Further, in the shock absorber D, a spring 1 that is housed in each pressure chamber of the hydraulic damper E and urges the hydraulic damper in a compressing direction and a spring 2 that urges the hydraulic damper in an extending direction. It has.

  That is, the springs 1 and 2 are interposed in parallel with the hydraulic damper E between the actuator A and the unsprung member W. Specifically, the piston P of the hydraulic damper E is connected to these. It is sandwiched and supported by two springs 1 and 2.

  As a result, the spring 1 is urged in the direction of compressing the hydraulic damper E, and the spring 2 is urged in the direction of extending the hydraulic damper E.

  These springs 1 and 2 serve to suppress transmission of high-frequency vibration of the unsprung member W to the actuator A side, that is, to the sprung member B side, and at the same time to the cylinder of the hydraulic damper E. Demonstrates the action of returning the piston to a predetermined position.

  That is, the problem that the piston P interferes with the cylinder C to deteriorate the riding comfort in the vehicle and the reliability of the shock absorber is reduced as in the case of a conventional shock absorber.

  In the shock absorber D, the hydraulic damper E is connected in series to the actuator A, and is disposed on the unsprung member W side. When high-frequency vibration such as vibration with relatively high acceleration is input to the unsprung member W when traveling or riding on a road surface protrusion, for example, the vibration energy is absorbed and the spring 1 described above is absorbed. , 2 combined with the vibration transmission suppressing effect, it acts to make it difficult to transmit vibration to the actuator A side.

  Here, the actuator A converts the vibration, which is a linear motion input from the unsprung member W side, into a rotational motion. However, the actuator A includes many rotating members, and the inertial mass is large and the high-frequency vibration is generated. On the other hand, there is a characteristic that vibration of the unsprung member W side is easily transmitted to the sprung member B due to an increase in the moment of inertia and the influence of friction. However, as described above, the hydraulic damper Since E absorbs the vibration and the springs 1 and 2 exhibit the vibration transmission suppressing effect, the transmission of the vibration to the actuator A is suppressed. Even in this case, there is an effect that the ride comfort in the vehicle is not deteriorated.

  Further, as described above, since the high-frequency vibration is prevented from directly acting on the actuator A by the hydraulic damper E, it is possible to suppress the transmission of high-frequency vibration with particularly high acceleration to the motor M. The reliability of the actuator A, which is the main component of the shock absorber D, can be improved, and the conventional shock absorber can be solved to improve the reliability of the shock absorber D.

  Moreover, 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.

  And since the said springs 1 and 2 are accommodated in the cylinder C of the hydraulic damper E, compared with the structure which provides a spring receiver and each spring in the hydraulic damper E outer peripheral side etc., the buffer D is provided. Slimming and miniaturization can be achieved.

  Since the springs 1 and 2 are housed in the cylinder C of the hydraulic damper E, when the springs 1 and 2 are coil springs, the diameter of the springs 1 and 2 can be reduced. The same spring constant can be secured even if the wire diameter is reduced compared to the case where each spring is provided on the outer peripheral side, and the cost of the springs 1 and 2 can be reduced correspondingly, and the shock absorber D can be reduced in weight. Is possible.

  Further, since it is not necessary to provide a spring receiver and each spring on the outer periphery of the hydraulic damper E, etc., the outer diameter of the hydraulic damper E can be increased accordingly. Since the amount of liquid in the damper E can be increased, a change in the temperature of the liquid can be suppressed and a change in the damping force characteristic of the hydraulic damper E can be prevented.

  Furthermore, since the linear motion of the actuator A is transmitted to the hydraulic damper E, that is, the motor M and the rotating member are connected to the sprung member B side, they are supported by the springs 1 and 2. The mass of the motor M is not included in the mass.

  Therefore, even if high-frequency vibrations act on the unsprung member W, the motor itself is supported by the spring with respect to the total mass that is supported by the springs 1 and 2 and vibrates between the sprung member B and the unsprung member W. Since it can be made lighter than a conventional shock absorber, vibration of the unsprung member W is difficult to be transmitted to the sprung member B, thereby further improving riding comfort.

  Further, as apparent from the above, since the motor M itself is not supported by the springs 1 and 2, the wiring of the motor M and the like can be easily routed, and high-frequency vibration is not directly input to the motor M itself. 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.

  Although the shock absorber D has been conceptually described above, a specific configuration of the shock absorber D will be shown and described below.

As shown in FIG. 2, the shock absorber D having a specific configuration is basically a hydraulic damper E connected to an unsprung member (not shown), and connected in series to the hydraulic damper E and not shown. An actuator A connected to the sprung member side, a spring 1 and a hydraulic damper that are interposed between the actuator A and the unsprung member in parallel with the hydraulic damper E and urge the hydraulic damper E in a compressing direction. And a spring 2 that urges E in the extending direction.

 Hereinafter, in detail, the actuator A includes a motor M and a motion conversion mechanism T.

 Although not specifically shown, the motor M is composed of a case 10, a rotor, and a stator. The rotor is composed of a shaft and a magnet attached to the outer periphery of the shaft. And is supported rotatably.

 On the other hand, the stator is composed of a core that is an armature core attached to the inner periphery of the case 10 so as to face the magnet, and a winding wound around the core, and the motor M is a so-called brushless motor. It is configured as.

 Incidentally, although not shown in the figure, the motor M is equipped with a magnetic sensor such as a Hall element or a resolver, an optical sensor, etc. as a rotor position detection means, and the state of rotational movement of the rotor (rotation angle, angular velocity, etc.) Accordingly, the damping force or the control force that suppresses the relative movement between the vehicle body and the axle generated by the shock absorber D can be controlled.

 Here, the motor M is a brushless motor, but as described above, various motors such as a brushed DC motor, an AC motor, an induction motor, and the like can be used as long as they can be used as an electromagnetic force generation source. .

  The motor M can be connected to a sprung member of a vehicle (not shown) via a mount 11. Specifically, the mount 11 includes a flange 13 at the lower end and a mount cylinder 12 formed in a hat shape. And an annular vibration-proof rubber 14 welded to the upper surface of the flange 13 in the figure, and an annular plate 15 welded to the upper end of the vibration-proof rubber 14, and the case 10 of the motor M is mounted on the mounting cylinder 12. The motor M is connected to the sprung member by fixing the plate 15 to a sprung member (not shown).

  Subsequently, the motion conversion mechanism T includes a screw shaft 16 and a ball screw nut 17 which is a screw nut.

  The screw shaft 16 is rotatably supported by the inner cylinder 20 via ball bearings 18 and 19. Specifically, the ball bearings 18 and 19 are held by a cap body 21 fitted in the upper end in FIG. 2 of the inner cylinder 20, and the cap body 21 is further provided with a flange 22 on the outer peripheral side. The flange portion 22 is fastened to the upper bottom portion of the mount cylinder 12 with a bolt or the like (not shown).

  In addition, a step portion 16 a is provided on the upper end side of the screw shaft 16 in the figure, and the ball bearings 18 and 19 are sandwiched between the step portion 16 a and the nut 99, and the screw shaft 16 is connected to the inner cylinder 20. Shaking is prevented.

  The upper end of the screw shaft 16 in the drawing is inserted into a hole (not shown) formed in the shaft core portion of the upper bottom portion of the mount cylinder 12, and is connected to the rotor of the motor M (not shown). Can be transmitted to the rotor of the motor M.

  In turn, the ball screw nut 17 which is a screw nut screwed to the screw shaft 16 is non-rotatably connected to the upper end in FIG. 2 of the connecting tube 40 having a smaller diameter than the inner tube 20. A plurality of grooves 40a along the axial direction are provided on the outer peripheral side, and a projection 20a formed on the inner peripheral side of the lower end in the figure of the inner cylinder 20 is inserted into the groove 40a. The groove 40a and the protrusion 20a prevent the inner cylinder 20 from rotating.

  That is, the ball screw nut 17 connected to the connecting cylinder 40 is prevented from rotating with respect to the inner cylinder 20.

  As described above, the actuator A in this specific shock absorber D includes the motor M, the screw shaft 16, the inner cylinder 20, the ball screw nut 17, and the connecting cylinder 40, and is connected to a sprung member (not shown) by the mount 11. Has been.

  From the above, the inner cylinder 20 is connected to the mount cylinder 12 via the cap body 21, and the motor M is fixed to the mount cylinder 12, so that when the motor M is driven to rotate, the screw Although the shaft 16 rotates, since the ball screw nut 17 is prevented from rotating with respect to the inner cylinder 20, the ball screw nut 17 exhibits a linear motion in the vertical direction in the figure.

  Conversely, when the ball screw nut 17 exhibits a linear motion in the vertical direction in the figure with respect to the screw shaft 16, the ball screw nut 17 is restricted from rotating by the connecting tube 40 and the inner tube 20. Is forcibly rotated, and the rotor of the motor M is forcibly rotated.

  Here, when the ball screw nut 17 is forced to exhibit a linear motion upon receiving an external force, the rotor of the motor M is forced to rotate as described above. An induced electromotive force is generated and a regenerative current flows, and the motor M generates an electromagnetic force that suppresses the rotation of the rotor.

  That is, by generating an induced electromotive force in the winding, the motor M regenerates energy to generate electromagnetic force, and the torque of the electromagnetic force acts on the rotor of the motor M, and the torque suppresses the rotational motion of the rotor. Will be.

  The torque that suppresses the rotation of the rotor acts as a force that suppresses the linear motion of the ball screw nut 17 by the motion conversion mechanism T, and a damping force in the shock absorber D.

  Therefore, the actuator A functions as an actuator that applies a propulsive force in a linear direction to the ball screw nut 17 when the motor M is driven, and has a function of suppressing the linear motion of the ball screw nut 17.

  The mount 11 is not limited to the above-described one, and other configurations can be adopted. That is, as long as the mount 11 functions as a mount, other configurations and shapes may be used.

  The inner cylinder 20 is slidably inserted into the outer cylinder 60 disposed on the outer peripheral side via a bearing 63.

  The outer cylinder 60 includes a suspension spring receiver 100 that supports the lower end of the suspension spring S that supports the mass of the sprung member of the vehicle at a predetermined position on the outer periphery of the intermediate portion. The suspension spring S is shown in FIG. As described above, the recess 14 a provided in the lower part on the outer peripheral side of the vibration-proof rubber 14 is interposed between the suspension spring receiver 100.

  With this configuration, the upper end of the suspension spring S is received by the anti-vibration rubber 14 even if excessive bumping occurs in the vehicle, so that the vibration transmitted to the sprung member side can be softly absorbed in the vehicle. The ride comfort can be improved.

  Further, as described above, the annular bearing 63 is disposed on the inner periphery of the upper end of the outer cylinder 60, so that the inner cylinder 20 is prevented from shaking relative to the outer cylinder 60, and the upper end opening of the outer cylinder 60 is also prevented. A cylindrical stopper member 66 is fitted, and an annular dust seal 67 disposed on the inner peripheral side of the stopper member 66 seals between the outer periphery of the inner cylinder 20 and the outer cylinder 60, and the outer cylinder 60. In the space formed by the inner cylinder 20, that is, entry of dust, dust, rainwater, etc. into the shock absorber D is prevented, and the screw shaft 16, the ball screw nut 17 and the motor which are the main members of the shock absorber D are prevented. The quality deterioration of M is prevented, and the reliability of the shock absorber D is improved.

 Further, since the screw shaft 16 and the ball screw nut 17 are accommodated in the inner cylinder 20 and the outer cylinder 60, the shock absorber D is reliable in this respect because it is not subjected to interference from a stepping stone or the like from the outside. Has been improved.

  Further, the upper end of the stopper member 66 comes into contact with a bellows-shaped bump stopper 25 provided on the outer peripheral side of the upper end in FIG. 1 of the inner cylinder 20 when the shock absorber D contracts to an arbitrary length. The shock when the shock absorber D contracts can be reduced. In addition, the lower end of the screw shaft 16 collides with the upper end of the rod 32 of the hydraulic damper E, which will be described later, that is, the so-called bottoming of the shock absorber D is prevented. Be improved.

  And the lower end opening part of the outer cylinder 60 is couple | bonded by the press injection etc. to the outer periphery of the reservoir cylinder 33 of the hydraulic damper E mentioned later.

  As shown in FIG. 3, the hydraulic damper E has a cylinder 30 and a piston 31 that is slidably inserted into the cylinder 30 and separates the upper and lower pressure chambers 35 and 36 in the figure. A rod 32 having one end connected to the piston 31 and a reservoir cylinder 33 covering the outer peripheral side of the cylinder 31 are provided.

  In more detail, the upper end opening of the cylinder 30 is fitted with a step (not shown) formed at the lower portion of the annular head member 37. The head member 37 is fitted inside the reservoir cylinder 33 and is fixed to the reservoir cylinder 33 by caulking the upper end opening of the reservoir cylinder 33, and the cylinder 30 and the reservoir cylinder are fixed by the head member 37. 33 is positioned concentrically.

  Further, the rod 32 is inserted into the inner peripheral side of the head member 37, and the head member 37 is sealed between the head member 37 and the reservoir cylinder 33 by the seal member 41 disposed on the outer peripheral side of the head member 37. A cylindrical rod guide 38 that is in sliding contact with the outer periphery of the rod 32 disposed on the inner peripheral side of the rod 32 and a seal member 42 that is also in sliding contact with the outer periphery of the rod 32 and seals between the rod 32 and the head member 37 are provided. The upper ends of the reservoir cylinder 33 and the cylinder 30 are sealed in a liquid-tight manner.

  On the other hand, a flanged disk-like valve body 43 is fitted to the lower end of the cylinder 30, and a bottomed cylindrical bottom member that seals the reservoir cylinder 33 in a liquid-tight manner on the inner periphery of the lower end of the reservoir cylinder 33. 61 is fitted.

  The valve body 43 is configured such that the outer peripheral side of the flange is in contact with the inner periphery of the bottom member 61 and is fitted to the lower end of the cylinder 30, so that the reservoir cylinder 33 and the cylinder 30 are positioned concentrically. .

  As described above, the outer periphery of the intermediate portion of the reservoir cylinder 33 is coupled to the lower end opening of the outer cylinder 60, and the bottom member 61 is an eye-shaped bracket capable of connecting the shock absorber D to the unsprung member of the vehicle. The shock absorber D is disposed in parallel with the suspension spring S and is interposed between the sprung member and the unsprung member by the eye bracket 64 and the mount 10.

  The valve body 43 includes a recess 43a provided at the bottom, passages 51 and 52 communicating the recess 43a and the pressure chamber 36, and damping force generating elements 53 and 54 provided in the middle of the passages 51 and 52. The recess 43a and a notch 43b communicating with the outer peripheral side of the flange are provided.

  The piston 31 includes passages 55 and 56 that connect the pressure chamber 35 and the pressure chamber 36, and damping force generation elements 57 and 58 provided in the middle of the passages 55 and 56.

  The upper end of the rod 32 in the figure is connected to the lower end side of the connecting cylinder 40, and an annular cushion member 70 is provided in the vicinity of the upper end of the rod 32 in the figure, and the cushion member 70 is provided with a hydraulic damper E. At the time of maximum compression, the head member 37 is brought into contact with the upper end in the figure to restrict the movement of the rod 32 toward the cylinder 30 and to prevent the direct collision between the connecting cylinder 40 and the cylinder 30 to alleviate the impact.

  Further, on both sides of the piston 31 of the rod 32, annular spring receivers 45 and 46 that are rotatable with respect to the rod 32 are provided, and a spring receiver 47 is also provided on the upper end side of the valve body 43, The spring 1 is interposed between the spring receiver 45 and the head member 37, and the spring 2 is also interposed between the spring receivers 46 and 47.

  That is, the spring 1 is housed in the pressure chamber 35 and biases the piston 31 downward in the drawing, that is, biases the hydraulic damper E in a compressing direction. The piston 31 is urged upward in the figure, that is, urged in the direction in which the hydraulic damper E extends.

  Accordingly, the piston 31 is urged from above and below in the drawing by the springs 1 and 2 and is positioned in the axial direction with respect to the cylinder 30 by the springs 1 and 2 and is maintained in the neutral position. Is done.

  Further, the mass elastically supported by the springs 1 and 2 is the connecting cylinder 40 ball screw nut 17, the rod 32 and the piston 31 of the hydraulic damper E, and the burdened mass is lighter than that of the conventional shock absorber.

  Thus, since the springs 1 and 2 are housed in the hydraulic damper E, the springs 1 and 2 are very advantageous in that they do not affect the overall length of the shock absorber D.

  Here, the advantage that the spring receivers 45 and 46 are rotatably attached to the rod 32 will be described. When the hydraulic damper E is expanded and contracted, the springs 1 and 2 expand and contract with the expansion and contraction. However, the springs 1 and 2 have a characteristic of rotating in the circumferential direction when expanding and contracting. An attempt is made to rotate in the circumferential direction relative to the receivers 45, 46, 47 and the head member 37.

  Since the spring receivers 45 and 46 are allowed to rotate with respect to the rod 32 with respect to the rotation of the springs 1 and 2, the rotation of the springs 1 and 2 is not hindered.

  That is, the springs 1 and 2 rotate with respect to the rod 32, the spring receiver 47 and the head member 37 together with the spring receivers 45 and 46 when expanding and contracting. The surface for supporting the springs 1 and 2 and the supporting surface of the spring 1 in the head member 37 are not gnawed.

  Therefore, since the spring receivers 45, 46, 47 and the head member 37 are not damaged, deterioration of the spring receivers 45, 46, 47 and the head member 37 can be prevented, and the reliability of the shock absorber D is improved.

  Further, since the washers 84 and 87 rotate together with the springs 1 and 2, no torque acts on the flange portion 93.

  Further, since the torque generated by the rotation of the springs 1 and 2 does not act on the rod 32 and does not rotate the rod 32 in the circumferential direction, the connection between the rod 32 and the connecting cylinder 40 is released. Is prevented.

  Since the torque from the springs 1 and 2 does not act on the rod 32, the friction force more than necessary is not generated between the groove 40a of the connecting cylinder 40 and the protrusion 20a of the inner cylinder 20, and the shock absorber D is smooth. In addition to preventing the expansion and contraction, it is possible to prevent deterioration of the connecting cylinder 40 and the inner cylinder 20.

  Therefore, the permissible means in the specific shock absorber D is the spring receivers 45 and 46 themselves, and by attaching the spring receivers 45 and 46 themselves to the rod 32 in this manner, The rotation of the springs 1 and 2 in the circumferential direction can be allowed easily and at low cost. In the above description, the permissible means are the spring receivers 45 and 46. However, the spring receiver 47 is rotatably attached to the valve body 43, and further between the spring 1 and the spring receiver 45 or the head member 37. An annular member such as a washer is interposed between the spring 2 and one of the spring receivers 46 and 47, and an annular member such as a washer is interposed to rotate the annular member and the springs 1 and 2 together. Therefore, the springs 1 and 2 may be permitted means for allowing rotation in the circumferential direction.

  Further, when the connection between the lower end opening of the outer cylinder 60 and the reservoir cylinder 33 of the hydraulic damper E is screwed, the reservoir cylinder 33 is rotated with respect to the outer cylinder 60, thereby The reservoir cylinder 33 can be moved back and forth in the axial direction with respect to 60, thereby enabling so-called vehicle height adjustment. However, even when the vehicle height is adjusted, the spring receivers 45, 46 described above are in relation to the rod 32. Thus, there is no concern that the rod 32 and the connecting cylinder 40 are uncoupled, and even during the adjustment, the spring receivers 45, 46, 47 and the head member 37 and thus the connecting cylinder 40 and the inner Deterioration of the cylinder 20 can be prevented.

  When the lower end opening of the outer cylinder 60 and the reservoir cylinder 33 of the hydraulic damper E are screwed together, a nut is screwed onto the outer periphery of the reservoir cylinder 33, and this nut is opened to the opening of the outer cylinder 60. It is desirable to prevent the reservoir cylinder 30 and the outer cylinder 60 from being loosened by abutting and tightening against the lower end of the part.

  Subsequently, returning to the description of the configuration of the hydraulic damper E, the pressure chambers 35 and 36 in the cylinder 30 of the hydraulic damper E are filled with a liquid such as hydraulic oil, and the cylinder 30 and the reservoir cylinder 33 are connected to each other. A predetermined amount of liquid is also filled in the gap between them, but an air chamber G is formed in the gap 44 with the liquid level O as a boundary, and the gap 44 functions as a reservoir.

  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.

  In the hydraulic damper E, when the rod 32 moves downward in the figure with respect to the cylinder 30, the piston 31 moves downward to expand the pressure chamber 35 and contract the pressure chamber 36.

  At this time, the liquid moves from the pressure chamber 36 through the passage 56 and the damping force generating element 58 to the pressure chamber 35, and the liquid corresponding to the rod intrusion volume into the cylinder 30 that is excessive in the cylinder 30 is stored in the reservoir. And move to the gap 44 through the passage 51 and the damping force generating element 53.

  The hydraulic damper E generates a damping force commensurate with the pressure loss that occurs when the liquid passes through the damping force generation elements 53 and 58.

  Conversely, when the rod 32 moves upward in the figure relative to the cylinder 30, the piston 31 moves upward to expand the pressure chamber 36 and contract the pressure chamber 35.

  At this time, the liquid moves from the pressure chamber 35 through the passage 55 and the damping force generating element 57 to the pressure chamber 36, and is liquid corresponding to the volume of the rod 32 that retreats from the cylinder 30 that is insufficient in the cylinder 30. Passes through the passage 52 and the damping force generating element 54 from the gap 44 as a reservoir 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 damping force generation elements 54 and 57.

  As the damping force generating elements 53, 54, 57, and 58, specifically, an orifice, a leaf valve, or the like may be used, and other elements may be used as long as they exhibit a predetermined damping action. Good.

 Since the connecting cylinder 40 of the actuator A is connected to the rod 32 of the hydraulic damper E as described above, the piston 31 connected to the rod 32 is coupled to the outer cylinder 60 via the reservoir cylinder 33. The shaft of the connecting cylinder 40 is also supported by the projection 20a of the inner cylinder 20 that is slidably contacted with the cylinder 30 and functions as a bearing and prevents the shaft blur on the lower end side of the connecting cylinder 40 and the outer cylinder 60 prevents the shaft shake. As a result, the shake of the screw shaft 16 with respect to the ball screw nut 17 is prevented, so that even if a lateral force is input to the shock absorber D, one of the ball screw nuts 17 is prevented. It is possible to prevent a load from being concentrated on the ball (not shown) of the portion, and to prevent deterioration of the ball or the screw groove of the screw shaft 16.

  In addition, since the deterioration of the ball or the screw groove of the screw shaft 16 can be prevented, the smoothness of each operation of the rotation of the screw shaft 16 with respect to the ball screw nut 17 and the movement of the shock absorber D in the expansion / contraction direction can be maintained. Since the smoothness of each of the above operations can be maintained, the function as the shock absorber D is not impaired, and the reliability of the shock absorber D is improved in this respect by adopting this configuration.

  Further, since the hydraulic damper E is formed as a double cylinder type, the overall length of the shock absorber D can be shortened, and in addition, since the springs 1 and 2 are housed in the hydraulic damper E, as described above. In addition, since the springs 1, 2, etc. do not affect the overall length of the shock absorber D, it becomes possible to minimize the overall length of the shock absorber D in combination with the double cylinder type hydraulic damper E, Thereby, even in the shock absorber D configured by connecting the hydraulic damper E to the actuator A in series, not only is the stroke secured, but also the mounting property to the vehicle is improved.

  And since the said springs 1 and 2 are accommodated in the cylinder C of the hydraulic damper E, the buffer D can be slimmed and reduced in size, and the diameter of the springs 1 and 2 can be reduced. As a result, the cost of the springs 1 and 2 can be reduced and the shock absorber D can be reduced in weight.

  Furthermore, since it is not necessary to provide a spring receiver and each spring on the outer periphery side of the hydraulic damper E, the outer diameter of the hydraulic damper E can be increased. Since the amount of liquid in the pressure damper E can be increased, a change in the temperature of the liquid can be suppressed to prevent a change in the damping force characteristic of the hydraulic damper E, and the outer diameter can be increased. The pressure receiving area can be increased, which is advantageous for generating a damping force.

  Further, since the springs 1 and 2 are housed in the hydraulic damper E, when assembling the shock absorber D, the actuator A side and the hydraulic damper E side can be assembled.

  In other words, the actuator A is an electric device including the motor M, and the hydraulic damper E is a hydraulic device, so the production line may be different, but each can be assembled, so each is produced in a separate factory. Even if it does, it is advantageous at the point that the buffer D which is a final product can be manufactured only by assembling both, and an assembling operation becomes easy.

  In the shock absorber D configured as described above, when the sprung member and the unsprung member of the vehicle receive a force from the road surface and linearly move relative to each other, the ball screw nut 17 connected to the axle side The screw shaft 16 connected to the sprung member side exhibits a linear relative motion, and this relative motion is converted into the rotational motion of the screw shaft 16 as described above and transmitted to the rotor of the motor M.

  When the rotor of the motor M exhibits a rotational motion, the winding in the motor M crosses the magnetic field of the magnet, and an electromagnetic force is generated by causing the motor M to regenerate energy by generating an induced electromotive force in the winding. The rotational torque generated by the electromagnetic force due to the induced electromotive force acts on the rotor of the motor M, and the rotational torque suppresses the rotational motion of the rotor.

  The effect of suppressing the rotational movement of the rotor is to suppress the rotational movement of the screw shaft 16, and the rotational movement of the screw shaft 16 is suppressed, so that the linear motion of the ball screw nut 17 is suppressed and buffered. The device D generates a control force that acts as a damping force in this case by the electromagnetic force, and absorbs and relaxes vibration energy.

  At this time, when the current is actively supplied to the winding from the external power source, the expansion and contraction of the shock absorber D is freely controlled by adjusting the rotational torque acting on the rotor, that is, the control force of the shock absorber D is generated. Since it is possible to control freely within a possible range, the damping characteristic of the shock absorber D can be made variable, or the shock absorber D can function as an actuator. In the case where the shock absorber D functions as an actuator in accordance with the force to perform appropriate control, the shock absorber D can also function as an active suspension.

 If it is not necessary to positively function as an actuator as described above, that is, if only a damping force is generated, it is not necessary to connect the motor M to an external power source, and the rotor of the motor M is forcibly forced. The linear relative motion between the screw shaft 16 and the ball screw nut 17 may be suppressed by the induced electromotive force generated in the winding when rotated, that is, by the rotational torque caused by the electromagnetic force generated only by energy regeneration. Of course.

  In this shock absorber D, since the hydraulic damper E is disposed on the unsprung member side, high frequency vibration is input from the road surface, and the actuator A cannot absorb vibration as described above. Even if it exists, it can suppress that this vibration absorbs a high frequency vibration with the hydraulic damper E, and this vibration is transmitted to the sprung member side by the springs 1 and 2.

  Therefore, even in the case of the specific shock absorber D, when the vehicle travels on a rough road or rides on a protrusion on the road surface, the unsprung member has, for example, high-frequency vibration such as vibration with relatively high acceleration. Even when the is input, there is an effect that the ride comfort in the vehicle is not deteriorated.

  Further, the torque of the springs 1 and 2 is not transmitted to the connecting cylinder 40 side by the spring receivers 45 and 46 which are the above-mentioned permissible means, and the frictional force generated between the groove 40a of the connecting cylinder 40 and the protrusion 20a of the inner cylinder 20 is generated. Since the smooth expansion and contraction movement of the actuator A can be suppressed and vibration is absorbed and suppressed smoothly, the ride comfort in the vehicle can be improved more reliably.

  Here, the damping force caused by the moment of inertia will be described briefly. The damping force generated on the actuator A side of the shock absorber D is roughly the moment of inertia of the screw shaft 16, the moment of inertia of the rotor of the motor M, and the moment of inertia of the ball screw nut 17. The sum of the force acting in the axial direction of the shock absorber D by the moment and the electromagnetic force generated by the motor M. Among these forces, the angular acceleration of the rotor of the motor M is the force due to the inertia moment of the rotating system. Since it is proportional to the acceleration of the expansion / contraction motion, it increases in proportion to the acceleration of the expansion / contraction motion of the shock absorber D. However, the inertia moment of the rotor and the screw shaft 16 is relatively large, and the influence on the damping force cannot be ignored.

  Since the force due to the moment of inertia of the rotor and screw shaft 16 is proportional to the acceleration of the expansion and contraction motion as described above, the force in the axial direction of the shock absorber D input to the shock absorber D from the road surface or the like. Since the shock absorber D acts in the opposite direction, the shock absorber D generates a damping force that does not depend on the electromagnetic force of the motor M. In particular, when a sudden axial force is input, a higher damping force is obtained. As a result, the vehicle occupant is perceived as having a jerky feeling.

  Therefore, a damping force due to the moment of inertia of the rotor and the screw shaft 16 is always generated prior to the damping force depending on the electromagnetic force, and the inertia of the rotor and the screw shaft 16 depending on the acceleration of the expansion and contraction motion of the shock absorber D. Since the damping force generated by the moment is difficult to control, the smaller the inertia moment of the rotor and screw shaft 16 is, the more the influence of the inertia moment of the rotor and screw shaft 16 on the damping force can be suppressed. The force acting in the axial direction of the shock absorber D due to the moment of inertia of the screw shaft 16 is absorbed by the hydraulic damper E and the springs 1 and 2 as described above, and the transmission of vibration with large acceleration to the sprung member is suppressed. As a result, the ride comfort in the vehicle is improved.

  Further, even when high-frequency vibration is applied to the unsprung member, the mass supported by the springs 1 and 2 does not include the masses of the motor M, the screw shaft 16 and the like having a large mass, and is compared with the conventional shock absorber. Since the weight is reduced, the force for transmitting the vibration input of the unsprung member to the sprung member is also reduced by the weight reduction, and the riding comfort in the vehicle can be improved.

  Further, since the mass supported by the springs 1 and 2 is reduced in weight and the natural frequency is increased, there is no harmful effect of resonance at a frequency in a region where the vehicle occupant feels particularly uncomfortable to ride. It is possible to improve the ride comfort.

  Further, since the hydraulic damper E is disposed below the spring, it is not necessary to secure a mounting space for the hydraulic damper E inside the vehicle body, so the motor M can be fixed particularly inside the vehicle body. The length of the relative motion portion of D is the length of the entire shock absorber D minus the length of the motor M, and the stroke of the shock absorber D can be easily secured. That is, as compared with the case where the motor M is attached to the lower part of the vehicle body, that is, outside the vehicle body, it is possible to take a longer stroke for the length of the motor M.

  Further, since the motor M can be disposed inside the vehicle body, it is possible to route an electric wire (not shown) that will be extended from each electrode of the motor M inside the vehicle body, It becomes easy to connect to the control device and the control circuit, and since the electric wire is housed in the vehicle body, the chance of deterioration of the electric wire can be reduced.

  In addition, since the motor M is particularly fixed to the inside of the vehicle body, it is possible to mount the shock absorber D on the vehicle without changing the mounting portion on the vehicle body side, so that the mounting portion on the vehicle body side can be standardized and the cost can be reduced. Since it is possible to transmit a shocking load in the case of full bouncing to the vehicle body via the mount portion, it is possible to prevent a large force from acting on the motor M. is there.

  Further, even in the shock absorber D having a specific configuration, the hydraulic damper E can be disposed upside down. In this case, the rod 32 is connected to the outer cylinder 60 and the cylinder 30 is connected to the connecting cylinder 40. Just keep it.

  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 figure which shows notionally the shock absorber of this invention. It is a longitudinal cross-sectional view of the buffer which is an example of a concrete structure. It is an expanded longitudinal cross-sectional view of the hydraulic-pressure damper part in the buffer which is an example of a concrete structure.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Spring 10 Case 11 Mount 16 Screw shaft 17 Ball screw nut 20 Inner cylinder 30 Cylinder 31 Piston 32 Rod 33 Reservoir cylinder 35, 36 Pressure chamber 40 Linking cylinder 45, 46 Spring receiver 47 which is permissible means Spring receiver 60 Outer cylinder 70 Cushion member 100 Suspension spring receiver A Actuator B Sprung member C Cylinder D Shock absorber E Hydraulic damper M Motor P Piston R Rod S Suspension spring T Motion conversion mechanism

Claims (4)

An actuator connected to the sprung member side of the vehicle having a motion conversion mechanism for converting linear motion into rotational motion and a motor to which the rotational motion converted by the motion conversion mechanism is transmitted; A piston that is freely inserted and separates two pressure chambers in the cylinder, and a rod having one end connected to the piston are provided, and the linear motion of the actuator is transmitted to one of the rod or the cylinder and the other of the rod or the cylinder is the vehicle A hydraulic damper connected to the unsprung member side, a spring housed in one of the pressure chambers and energized in a direction to compress the hydraulic damper, and a hydraulic damper housed in the other pressure chamber And a spring for biasing in a direction to extend the shock absorber. The shock absorber according to claim 1, wherein the piston is sandwiched from both ends by the springs. The shock absorber according to claim 1 or 2, further comprising an allowance means for allowing rotation of each spring in a circumferential direction. The shock absorber according to any one of claims 1 to 3, wherein the hydraulic damper includes a reservoir on an outer peripheral side of the cylinder.

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