Patent Publication Number: US-2010117277-A1

Title: Suspension device

Description:
FIELD OF ART 
     The present invention relates to an improvement of a suspension device. 
     BACKGROUND ART 
     As a suspension device of this type, there has been proposed a damper comprising a hydraulic damper and an actuator for imparting a propelling force to a piston rod of the hydraulic damper, as is disclosed in Japanese Patent Laid-Open Publication No. 2001-180244. According to this proposal, a rod of the hydraulic damper is formed in a cylindrical shape, an internal thread portion is formed on an inner periphery side of the rod, a shaft connected at one end thereof to a rotor of a motor and at an opposite end thereof to an external thread member which is threadably engaged with the internal thread portion of the rod of the hydraulic damper, and the shaft is inserted through the rod, and thus, the piston rod of the hydraulic damper is constituted by the shaft and the rod (see, for example, Patent Literature 1). 
     According to the above proposal, force which is produced at the time of making the piston rod extend or retract by relatively moving the shaft and rod axially with use of the motor is added to a damping force developed in the hydraulic damper, that is, the motor torque is converted to force acting in the direction of a relative movement between the shaft and the rod, which force is exerted additionally on the damping force of the hydraulic damper to damp vibration. 
     Further, a suspension device disclosed in Japanese Patent Laid-Open Publication No. Hei 08 (1996)-197931 is made up of a coil spring which supports a sprung member of a vehicle resiliently, an actuator including a screw shaft threaded rotatably with a ball screw nut connected to an unsprung member and a motor connected to one end of the screw shaft and supported resiliently by a sprung member while being interposed between a pair of springs, and a hydraulic damper fixed to the sprung member to damp a vertical vibration of the motor. A relative movement between a vehicle body and an axle is controlled actively with rotational torque developed by the motor. 
     DISCLOSURE OF THE INVENTION 
     However, the above conventional dampers involve the following problem. 
     In the suspension devices disclosed in Japanese Patent Laid-Open Publication Nos. 2001-180244 and Hei 08 (1996)-197931, the actuator and the hydraulic damper are directly coupled with each other, so upon input of such a high-frequency vibration as thrusting up from a road surface, a damping force is generated at the same time when the hydraulic damper is compressed. 
     On the other hand, if the actuator can retract without resistance, the foregoing vibration is not transmitted to the sprung member side, but since the moment of inertia of the rotor of the motor in the actuator is large, the extension or retraction of the actuator cannot follow a high-frequency vibration, resulting in the actuator assuming a rod-like state. In this state, the vibration is apt to be transmitted to the sprung member and hence it is impossible to improve the ride comfort in the vehicle. 
     The present invention has been accomplished in view of the above-mentioned problem and it is an object of the present invention to provide a suspension device capable of improving the ride comfort in a vehicle while adopting a construction comprising an actuator and a hydraulic damper. 
     According to the present invention, for achieving the above-mentioned object, there is provided a suspension device interposed between a sprung member and an unsprung member of a vehicle, the suspension device comprising an actuator, a hydraulic damper and a direction changing mechanism for changing a linear motion of the actuator into a linear motion in an opposite direction and transmitting the opposite linear motion to the hydraulic damper. 
     According to the suspension device of the present invention, when a high-frequency vibration acts on the unsprung member, the drawback that the vibration is apt to be transmitted to the sprung member under the influence of moment of inertia in the actuator is remedied, whereby it is possible to improve the ride comfort in the vehicle. 
     Also in the event of striking on a projection or passing a depression during a turning motion, it is possible to surely prevent a bottom contact of the hydraulic damper in the suspension device disposed on an outer wheel side on which the vehicle load is increased, whereby the ride comfort in the vehicle can be improved effectively. Besides, since it is possible to prevent the bottom contact of the hydraulic damper located on the outer wheel side on which an impact tends to be large, there is no fear of a functional deterioration of the suspension device and hence the reliability of the suspension device is improved remarkably. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram showing conceptually a suspension device according to an embodiment of the present invention. 
         FIG. 2  is a diagram showing a retracting operation of the suspension device of the embodiment. 
         FIG. 3  is a diagram showing an extending operation of the suspension device of the embodiment. 
         FIG. 4  is a diagram showing another direction changing mechanism. 
         FIG. 5  is a diagram showing a still another direction changing mechanism. 
         FIG. 6  is a diagram showing a modification of the still another direction changing mechanism. 
         FIG. 7  is a diagram showing another modification of the still another direction changing mechanism. 
         FIG. 8  is a diagram showing a combined construction of both a hydraulic damper and a direction changing mechanism. 
         FIG. 9  is a diagram showing another combined construction of both a hydraulic damper and a direction changing mechanism. 
         FIG. 10  is a diagram showing a still another combined construction of both a hydraulic damper and a direction changing mechanism. 
     
    
    
     BEST MODE FOR CARRYING OUT THE INVENTION 
     The present invention will be described below by way of embodiments thereof illustrated in the drawings. 
     As shown in  FIG. 1 , a suspension device S according to an embodiment of the present invention includes an actuator A, a hydraulic damper D, and a direction changing mechanism T for changing a linear motion of the actuator A into a linear motion in an opposite direction and transmitting the opposite linear motion to the hydraulic damper D. The suspension device S is interposed between a sprung member B and an unsprung member W in a vehicle. 
     The actuator A includes a motion transforming mechanism H for transforming a linear motion into a rotational motion and a motor M to which the rotational motion obtained by the motion transforming mechanism H is transmitted. The motion transforming mechanism H includes a rotating member h 1  connected directly or indirectly to a rotor (not shown) of the motor M and performing a rotational motion and a linear motion member h 2  adapted to perform a linear motion with the rotational motion of the rotating member h 1 . For example, the motion transforming mechanism is constituted by a feed screw mechanism comprising a screw shaft and a screw nut, or a rack and a pinion, or a worm gear. 
     The actuator A uses the motor M as a drive source, so in case of adopting the rotating member h 1 , i.e., the feed screw mechanism, in the motion transforming mechanism H, a rotational motion of a rotating-side member, i.e., either the screw shaft or the screw nut, is transmitted to the motor M. In case of imparting electrical energy to the motor M to drive the motor, the rotating member h 1  is rotated and the linear motion member h 2  is allowed to perform a linear motion, that is, the function as an actuator can be exhibited. 
     When the rotational motion is inputted to the motor M forcibly from the rotating member h 1 , the motor produces torque acting to suppress the rotational motion of the rotating member h 1  on the basis of an induced electromotive force, thus functioning to suppress the linear motion of the linear motion member h 2 . In this case, the motor M regenerates externally-inputted kinetic energy into electric energy and the linear motion of the linear motion member h 2  is suppressed with the resulting regenerative torque. 
     Thus, in the actuator A, thrust can be imparted to the linear motion member h 2  by positive generation of torque on the motor M. Further, in the case where the linear motion member h 2  is compelled to perform a linear motion with an external force, the linear motion of the linear motion member h 2  can be suppressed with the regenerative torque developed by the motor M. 
     In the suspension device S, not only a relative movement between the sprung member B and the unsprung member W can be suppressed with the thrust of the linear motion member h 2  which is induced by the actuator A, but also it is possible to make an attitude control for the sprung member B, more particularly, the vehicle body, by utilizing the function as the actuator. Thus, the function as an active suspension can also be exhibited. 
     A reduction mechanism, a link mechanism which permits the transfer of a rotational motion, or a joint, may be interposed between the motor M and the rotating member insofar as the motor M and the rotating member h 1  in the motion transforming mechanism H are connected together so as to permit the transfer of a rotational motion. 
     As the motor M, there may be used any of various types insofar as the above-mentioned function can be implemented. For example, there may be used a DC or AC motor, an induction motor, or a synchronous motor. 
     In the above construction, the actuator A is provided with the motion transforming mechanism H, but in the case where the drive source of the actuator A is a linear motor, the motion transforming mechanism H may be omitted. In this case, the linear motion member may be actuated directly by the linear motor. 
     As to the hydraulic damper D, although a concrete construction thereof will be described later, it includes a cylinder C, a piston P inserted slidably into the cylinder C and defining therein two pressure chambers to be filled with liquid, and a rod R connected at one end thereof to the piston P. The hydraulic damper D produces a predetermined damping force upon extension or retraction. 
     In the damper being considered, the hydraulic damper D is interposed between the actuator A and the unsprung member W mainly for the purpose of absorbing a high-frequency vibration. More specifically, one end of the hydraulic damper D is connected to the linear motion member of the actuator A and an opposite end thereof is connected to the unsprung member W. That is, the actuator A is connected to the sprung member B lest vibration should be transmitted to the motor M which is the drive source of the actuator A. 
     The direction changing mechanism T for transforming the linear motion of the actuator A into a linear motion in the opposite direction and transmitting the opposite linear motion to the hydraulic damper D is disposed between the hydraulic damper D and the actuator A. 
     As illustrated in the drawing, the direction changing mechanism T includes an actuator-side rack r 1  provided on the linear motion member h 2  which performs the linear motion of the actuator A, a damper-side rack r 2  provided at one end of the hydraulic damper D, and a gear G disposed between the actuator-side rack r 1  and the damper-side rack r 2  and meshing with both racks. For example, when the linear motion member h 2  of the actuator A strokes upwards in  FIG. 1 , the hydraulic damper D performs an extending motion, while when the linear motion member h 2  strokes downwards in  FIG. 1 , the hydraulic damper D performs a retracting motion. 
     A rotary shaft of the gear G may be installed so as to permit only movement in the vertical direction with respect to the sprung member B and the unsprung member W and inhibit movement in lateral directions, i.e., in the front and rear direction (the direction piercing through the paper surface) in  FIG. 1  and in the right and left direction in  FIG. 1 . More specifically, guides g 1  and g 2  which are tubes or rods extending in the vertical direction in  FIG. 1  are provided in the actuator A and the hydraulic damper D, respectively, and there is further provided a base portion g 3  adapted to slide with respect to those guides and hold the rotary shaft of the gear G. In the illustrated construction, the gear G is constituted by a single gear. However, in the case where the extension or retraction of the actuator A is to be transmitted in a decelerated or accelerated state to the hydraulic damper D, there may be used a gear mechanism comprising an odd number of gears. 
     Thus, with the direction changing mechanism T, the linear motion of the linear motion member h 2  in the actuator A is changed into a linear motion in the opposite direction, which opposite linear motion is transmitted to the hydraulic damper D. 
     The damper-side rack r 2  provided in the hydraulic damper D may be installed on one of the cylinder C and the rod R. Therefore, the other of the cylinder C and the rod R may be connected to the unsprung member W. Thus, the hydraulic damper D may be interposed between the direction changing mechanism T and the unsprung member W either in an erected state or an inverted state. 
     The suspension device S is further provided with a suspension spring SP interposed between the sprung member B and the unsprung member W. The sprung member B is supported by the suspension spring SP. 
     That is, in the suspension device S, the hydraulic damper D is connected in series with the actuator A although the direction changing mechanism T is interposed therebetween; besides, the hydraulic damper D is disposed on the unsprung member W side. Therefore, when a high-frequency vibration such as a vibration of a relatively large acceleration is inputted to the unsprung member W while the vehicle is running on a rough road or strikes on a projection on a road surface, the hydraulic damper D absorbs this vibration energy and acts to make the transmission of the vibration to the actuator A side difficult, coupled with the foregoing vibration transfer suppressing effect obtained by biasing means. 
     Next, a description will now be given about the operation of the suspension device S constructed as above. When the vehicle gets over a projection on a road surface during travel, as shown in  FIG. 2 , a thrusting-up vibration is inputted to the suspension device S, whereby the hydraulic damper D retracts so as to absorb the vibration and the whole of the hydraulic damper D moves upwards. 
     Upon this upward movement of the hydraulic damper D, the actuator A is moved in the opposite, downward direction by the direction changing mechanism T. At this time, the rotor of the motor M and the rotating member h 1  in the actuator A are large in the moment of inertia, and even if the extension or retraction of the actuator A is impeded by the moment of inertia, the suspension device S retracts as a whole by virtue of the above operation. 
     That is, when the vehicle strikes on a projection on a road surface, the high-frequency vibration of the unsprung member W is difficult to be transmitted to the sprung member B since the suspension device S is apt to retract. 
     On the other hand, when the vehicle passes a depression formed in a road surface during travel, as shown in  FIG. 3 , the unsprung member W performs a descending motion and a vibration acting to extend the suspension device S is inputted. In this case, the hydraulic damper D extends so as to absorb the vibration and the whole of the hydraulic damper D moves downwards. 
     Upon this downward movement of the hydraulic damper D, the actuator A is moved in the opposite, upward direction by the direction changing mechanism T. Now, the actuator A transforms the vibration as a linear motion inputted from the unsprung member W side into a rotational motion. In this connection, the actuator A is provided with many rotating members, the inertial mass thereof is large and so is the moment of inertia against a high-frequency vibration, and the influence of friction exists. Consequently, there is provided a characteristic that the vibration on the unsprung member W side is easy to be transmitted to the sprung member B. Further, the moment of inertia of the rotating member h 1  is large, and particularly upon input of a high-frequency vibration, the extension or retraction of the actuator A tends to be impeded by the moment of inertia. However, with the above operation, the suspension device S extends as a whole. 
     That is, when the vehicle passes a depression formed in a road surface, the high-frequency vibration of the unsprung member W is difficult to be transmitted to the sprung member B since the suspension device S is apt to extend. 
     Thus, in the suspension device S, when such a high-frequency vibration acts on the unsprung member W, it is possible to remedy the drawback that the vibration is easily transmitted to the sprung member B under the influence of the moment of inertia in the actuator A, and hence possible to improve the ride comfort in the vehicle. 
     Further, during a turning motion of the vehicle, the vehicle body undergoes rolling and the vehicle load shifts to the outer wheel side rather than the inner wheel side. For suppressing such a condition, force acting in the direction to lift the sprung member B is created in the suspension device S disposed on the outer wheel side so as to offset lateral acceleration of the vehicle body. 
     When this is implemented, thrust is developed in the direction to extend the actuator A, but the hydraulic damper D is extended by the intervention of the direction changing mechanism T, and the piston P of the hydraulic damper D assumes an upper position in the cylinder C by suppressing the rolling. 
     When an outer wheel strikes on a projection on a road surface in such a state, the hydraulic damper D displays a retracting motion, but since the piston P of the hydraulic damper D assumes an upper position in the cylinder C, there is a margin of the downward stroke of the piston P and hence the contact of the piston P with a lower end of the cylinder C, i.e., the so-called bottom contact, is prevented. 
     Conversely, in the case of the suspension device S disposed on an inner wheel side, the bottom contact is apt to occur in contrast with the above operation, but, as mentioned above, the suspension device S is apt to retract and the vehicle load is shifted to the outer wheel side, so that even if the bottom contact should occur, the resulting shock is weaker than in the conventional suspension device. In the conventional suspension device, the bottom contact is apt to occur in the hydraulic damper located on the outer wheel side on which the vehicle load is increased and on which an impact tends to be large. In the suspension device S, however, the bottom contact is sure to be prevented in the hydraulic damper located on the outer wheel side. 
     Thus, in the suspension device S, even when the vehicle strikes on a projection or passes a depression during a turning motion, not only the ride comfort in the vehicle can be improved, but also it is possible to positively prevent the bottom contact of the hydraulic damper D in the suspension device S disposed on an outer wheel side on which the vehicle load is increased, thus making it possible to improve the ride comfort in the vehicle effectively. Besides, since the bottom contact of the hydraulic damper D on the outer wheel side on which a large shock tends to be induced can be prevented, there is no fear of causing a functional deterioration of the suspension device S, so that the reliability of the suspension device S is improved to a remarkable extent. 
     Moreover, since a direct exertion of a high-frequency vibration on the actuator A is prevented by the hydraulic damper D as described above, the transfer of particularly a high-frequency vibration of a large acceleration to the motor M is prevented, so that the reliability of the actuator A as a principal component of the suspension device S is improved. 
     Further, since the above construction permits improvement of the working environment of the actuator A, it also becomes possible to reduce the cost of the actuator A. 
     Moreover, because of the construction that a linear motion of the actuator A is transmitted to the hydraulic damper D, that is, because of the construction that the motor M and the rotating member h 1  are connected to the sprung member B, a large mass such as the mass of the motor M is not included in the mass borne by the suspension spring SP. 
     Therefore, even if a high-frequency vibration acts on the unsprung member W, the vibration of the unsprung member W is difficult to be transmitted to the sprung member B since the total mass of vibration between the sprung member B and the unsprung member W can be made lighter than in the conventional damper in which the motor M itself is supported by a spring, whereby it becomes possible to further improve the ride comfort. 
     Further, as will be apparent from the above description, since the motor M itself is not supported by the suspension spring SP, layout of, for example, wiring of the motor M is easy; besides, since a high-frequency vibration is not directly inputted to the motor M itself, there is no fear of damage to the wiring. Accordingly, the damper D is improved in its onboard-ability onto a vehicle and is thus more practicable. 
     If the position of the piston P in the hydraulic damper D is to be established beforehand with respect to the cylinder C, this can be done by connecting an upper end of the hydraulic damper D, or an upper end of the rod R in  FIG. 1 , to an intermediate point of the suspension spring SP. By doing so, when no load is imposed on the hydraulic damper D by the suspension spring SP, the piston P is returned to a predetermined position with respect to the cylinder C, whereby the occurrence of a situation such that the piston P stops at an offset position with respect to the cylinder C by extension or retraction of the hydraulic damper D is prevented, thus making it possible to prevent the bottom contact of the hydraulic damper D more positively. 
     Instead, springs for holding the piston P grippingly may be disposed within each of pressure chambers in the hydraulic damper D. In this case, springs are disposed respectively between the piston P and the upper end of the cylinder C and between the piston P and the lower end of the cylinder C to hold the piston P in a sandwiching manner. Thus, the piston P can be established its position with respect to the cylinder C and there can be obtained the same effect as in case of connecting the upper end of the hydraulic damper D to an intermediate position of the suspension spring SP. 
     Next, a description will be given about a direction changing mechanism of another construction. As shown in  FIG. 4 , this direction changing mechanism, indicated at T 1 , includes a bar  1  which is allowed to rotate about a fulcrum (a). One end of the bar  1  is connected to the linear motion member h 2  rotatably while permitting a stroke of the member h 2  which performs a linear motion of the actuator A, and an opposite end of the bar  1  is rotatably connected to one end of the hydraulic damper D so as to permit extension and retraction of the hydraulic damper D. 
     More specifically, the bar  1  is made rotatable about the fulcrum (a) located at a central position, with elongated axial holes  2  and  3  being formed in both ends respectively of the bar  1 . A pin  4  is provided on an end portion of the linear motion member h 2  so as to be inserted into the elongated hole  2  and a pin  5  is provided on an end portion of the rod R of the hydraulic damper D so as to be inserted into the elongated hole  3 . Like the rotary shaft of the gear G in the direction changing mechanism T described above, the fulcrum (a) may be provided so that only the vertical movement is allowed with respect to the sprung member B and the unsprung member W. 
     Thus, the direction changing mechanism T 1  can also function like the direction changing mechanism T described above. That is, even if the direction changing mechanism T 1  is adopted, there can be obtained the foregoing function and effect of the suspension device S. In this case, the lever ratio can be changed by appropriately setting the position of the fulcrum (a) on the bar  1 . 
     The following description is now provided about a direction changing mechanism of a still another construction. As shown in  FIG. 5 , this direction changing mechanism, indicated at T 2 , includes an actuator-side piston  10  connected to the linear motion member h 2  of the actuator A, a damper-side piston  11  connected to one end of the rod R of the hydraulic damper D, a changing cylinder  12  into which the actuator-side piston  10  and the damper-side piston  11  are slidably inserted, and a chamber  13  filled with fluid, the chamber  13  being defined by both actuator-side piston  10  and damper-side piston  11  within the changing cylinder  12 . 
     More specifically, the changing cylinder  12  is formed in a cylindrical U shape so that open ends thereof face in the same direction, and the actuator-side piston  10  and the damper-side piston  11  are inserted into the changing cylinder  12  from both open ends respectively of the cylinder to define the chamber  13  within the cylinder. 
     Therefore, when the actuator-side piston  10  moves downwards in  FIG. 5 , the other damper-side piston  11  moves upwards in the same figure. Conversely, when the damper-side piston  11  moves downwards in  FIG. 5 , the other actuator-side piston  10  moves upwards in the same figure. In this way the linear motion of the linear motion member h 2  in the actuator A is changed into a linear motion in the opposite direction, which can be transmitted to the hydraulic damper D. 
     Like the rotary shaft of the gear G in the direction changing mechanism T described above, the changing cylinder  12  may be installed so as to permit only the vertical movement with respect to the sprung member B and the unsprung member W. 
     Thus, the direction changing mechanism T 2  can also function like the direction changing mechanism T described above. That is, even if the direction changing mechanism T 2  is adopted, there can be obtained the foregoing function and effect of the suspension device S. 
     Although the changing cylinder  12  is disposed with its open ends facing upwards in  FIG. 5 , the top and the bottom may be reversed, that is, the cylinder  12  may be disposed with its open ends facing downwards. Moreover, as shown in  FIG. 6 , in connecting the damper-side piston  11  with the rod R or the cylinder C in the hydraulic damper D, the rod R or the cylinder C may be connected to the damper-side piston  11  so as to pass through the chamber  13 . Further, the changing cylinder  12  may be formed in such a double cylinder shape as shown in  FIG. 7 . 
     Next, a description will be given about a combined construction of both hydraulic damper and direction changing mechanism. As shown in  FIG. 8 , a hydraulic damper D 1  includes a first cylinder  20 , a second cylinder  21  disposed in parallel with the first cylinder  20 , an actuator-side piston  23  connected to the linear motion member h 2  of the actuator A and inserted slidably into the first cylinder  20  to define a first chamber  22  within the first cylinder  20 , a vehicle-side piston  25  connected to the unsprung member W and inserted slidably into the second cylinder  21  to define a second chamber within the second cylinder  21 , a passage  26  which provides communication between the first chamber  22  and the second chamber  24  in such a manner that the moving direction of the actuator-side piston  23  and that of the vehicle-side piston  25  are opposite to each other, and a damping force generating element  27  disposed in the passage  26 . The first chamber  22  and the second chamber  24  are filled with liquid such as working fluid. 
     More specifically, the first cylinder  20  and the second cylinder  21  are formed in a cylindrical shape and are connected in parallel with each other. Openings of both the first cylinder  20  and the second cylinder  21  face upward in  FIG. 8 . 
     The actuator-side piston  23  is inserted into the first cylinder  20  from the open end of the same cylinder to form the first chamber  22  in a lower portion of the first cylinder  20 , while the vehicle-side piston  25  is inserted into the second cylinder  21  from the open end of the same cylinder to form the second chamber  24  in a lower portion of the second cylinder  21 . The first chamber  22  and the second chamber  23  are brought into communication with each other through the passage  26 . The damping force generating element  27 , e.g., a throttle valve, is mounted in the passage  26 . 
     According to this construction, when the actuator-side piston  23  moves downwards in  FIG. 8 , the vehicle-side piston  25  moves upwards in the same figure. Conversely, when the vehicle-side piston  25  moves downwards in  FIG. 8 , the actuator-side piston  23  moves upwards in the same figure. In this way, the linear motion of the linear motion member h 2  of the actuator A is changed into a linear motion in the opposite direction, which can be transmitted to the hydraulic damper D. 
     When the operation of the actuator-side piston  23  and that of the vehicle-side piston  25  are performed, liquid interchanges between the first chamber  22  and the second chamber  24  through the passage  26 , and when liquid passes through the passage  26 , there occurs a pressure loss by the damping force generating element  27 , thus creating a damping force to suppress the operation of the actuator-side piston  23  and that of the vehicle-side piston  25 . 
     Since the hydraulic damper D 1  is connected to the sprung member B or the unsprung member W, it is not necessary to adopt any special mechanism for supporting the direction changing mechanism. 
     Thus, the hydraulic damper D 1  functions as both a damping force generation source and a direction changing mechanism and hence can function in the same manner as the foregoing hydraulic damper D and direction changing mechanism T. Accordingly, there are obtained the foregoing function and effect of the suspension device S. 
     Although the first cylinder  20  and the second cylinder  21  are disposed with their open ends facing upwards in  FIG. 8 , the top and the bottom may be reversed, that is, both cylinders may be disposed with their open ends facing downwards. There may be adopted such an arrangement as shown in  FIG. 9 , in which the open ends of the first cylinder  20  and the second cylinder  21  are alternated, and the first chamber  22  is disposed in a lower portion of the first cylinder  20 , while the second chamber  24  is disposed in an upper portion of the second cylinder  21 , and the first chamber  22  and the second chamber  24  are put in communication with each other through the passage  26 . Further, in connecting the vehicle-side piston  25  with the sprung member B or the unsprung member W, a rod-like member extending from the sprung member B or the unsprung member W while passing through the second chamber  24  may be connected to the vehicle-side piston  25 . The hydraulic damper D 1  may be formed in a double cylinder shape as shown in  FIG. 10 . 
     The present invention have been described above by way of embodiments thereof, but it goes without saying that the scope of the present invention is not limited to the details itself illustrated in the drawings or described above. 
     INDUSTRIAL APPLICABILITY 
     The suspension device of the present invention is applicable to a vehicular suspension.