JP2005127386A - Rubber bush mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To control a spring constant of a rubber bush mount at good responsiveness with a small and light structure. <P>SOLUTION: A polymer actuator 18 with a conductive polymeric material contacting an electrolyte is embedded inside of a rubber bush 17 connecting an outer cylinder 14 and an inner cylinder 16 of a rubber bush mount 13. An electric potential of the conductive polymeric material is made higher than that of the electrolyte to extend the conductive polymeric material. Also, the electric potential of the conductive polymeric material is made lower than that of the electrolyte to shrink the conductive polymeric material, so as to change a spring constant of the rubber bush 17 by telescopic driving of the polymer actuator 18. This can secure rigidity of a suspension device in turning, improve riding comfort in a straight traveling, control a toe by a side force of a tire, and realize an active anti-vibration function and the like matched with vibration input from a road surface at good responsiveness with a simple and low-cost structure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rubber bush mount that elastically connects a suspension arm of an automobile to a vehicle body or a knuckle.

  A rubber bush mount that elastically connects the suspension arm of an automobile to a vehicle body or a knuckle consists of an outer cylinder that is fixed to the end of the suspension arm by press fitting, an inner cylinder that is fixed to the vehicle body or the knuckle by bolts, etc. A rubber bush connecting the cylinder and the inner cylinder is provided, and in order to adjust the spring constant of the rubber bush, a space called “tickling” is formed at an appropriate portion thereof.

In Patent Document 1 below, in order to make the spring constant of the rubber bush mount variable, the hardness of the rubber bush is changed by controlling the hydraulic pressure supplied to the oil chamber formed inside the rubber bush. What is to be done is described.
Japanese Patent No. 2998224

  However, what is described in Patent Document 1 requires an oil pump, a control valve, hydraulic piping, and the like in order to control the hydraulic pressure supplied to the oil chamber formed inside the rubber bush. However, there is a problem that not only the increase in weight and the cost increase but also the supply / discharge of oil to the oil chamber takes time, and sufficient response cannot be obtained.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to make it possible to control the spring constant of a rubber bush mount with high responsiveness with a small and lightweight structure.

  In order to achieve the above object, according to the invention described in claim 1, in the rubber bush mount in which the outer cylinder fixed to the suspension arm and the inner cylinder fixed to the vehicle body or the knuckle are connected by the rubber bush, A polymer actuator with a conductive polymer material in contact with the electrolyte is embedded in the rubber bush, the potential of the conductive polymer material is made higher than the potential of the electrolyte, and the conductive polymer material is stretched. The rubber bush mount is characterized in that the potential of the conductive polymer material is made lower than the potential of the electrolyte and the conductive polymer material is contracted to drive the expansion and contraction of the polymer actuator to change the spring constant of the rubber bush. Is proposed.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the driving state detecting means for detecting the driving state of the vehicle, and a high level according to the driving state of the vehicle detected by the driving state detecting means. A rubber bush mount characterized by comprising control means for controlling the operation of the molecular actuator is proposed.

  The solid electrolyte 28 of the embodiment corresponds to the electrolyte of the present invention, the lateral acceleration sensor 29 of the embodiment corresponds to the traveling state detection means of the present invention, and the electronic control unit U of the embodiment corresponds to the control means of the present invention. Correspond.

  According to the configuration of claim 1, since the polymer actuator in which the conductive polymer material is brought into contact with the electrolyte is embedded in the rubber bush connecting the outer cylinder and the inner cylinder of the rubber bush mount, the conductive polymer The potential of the material is made higher than the potential of the electrolyte to elongate the conductive polymer material, and the potential of the conductive polymer material is made lower than the potential of the electrolyte to shrink the conductive polymer material. The spring constant of the rubber bush can be changed by driving the molecular actuator to expand and contract. As a result, the rigidity of the suspension system during turning, improvement of ride comfort during straight running, toe control by the side force of the tire, active anti-vibration function according to the vibration input from the road surface, etc. are simple and low. It can be realized with a cost structure and good responsiveness.

  According to the configuration of the second aspect, since the control means controls the operation of the polymer actuator according to the running state of the vehicle detected by the running state detection means, the rubber bush mount is not required for special operation by the driver. The characteristic can be changed to a characteristic suitable for the running state of the vehicle.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 5 show a first embodiment of the present invention. FIG. 1 is a front view of a suspension arm of an automobile, FIG. 2 is an enlarged sectional view of a part 2 in FIG. 1, and FIG. FIG. 4 is a perspective view of the conductive polymer tube, and FIG. 5 is an explanatory view of the action when the polymer actuator is operated.

  As shown in FIG. 1, a suspension arm 10 of an automobile includes an arm body 11 and cylindrical connection portions 12 and 12 integrally formed at both ends thereof, and is supported by the connection portions 12 and 12. One of the rubber bush mounts 13 and 13 is connected to the vehicle body, and the other is connected to the knuckle.

  As is clear from FIG. 2, the rubber bush mount 13 includes an outer cylinder 14 that is press-fitted into the connection portion 12 of the suspension arm 10, and an inner cylinder that is disposed inside the outer cylinder 14 and is fixed to the vehicle body or knuckle with a bolt 15. 16 and a rubber bush 17 that connects the outer cylinder 14 and the inner cylinder 16, and two polymer actuators 18, 18 are embedded in the rubber bush 17. The polymer actuators 18 and 18 are substantially cylindrical, and are arranged on both sides of the inner cylinder 16 in a state where the axis thereof is aligned with the axis L of the arm body 11.

  As apparent from FIG. 3, the polymer actuator 18 includes a bottomed cylindrical cylinder 21, a bottomed cylindrical piston 22 that is slidably fitted inside the cylinder 21, and the cylinder 21 and the piston 22. And an actuator element 23 that is spirally wound and accommodated in a cylindrical space partitioned by. The actuator element 23 is formed by bundling about 100 conductive polymer tubes 24 shown in FIG. 4 and caulking both ends thereof with fixing rings 25 and 25.

  As shown in FIG. 4, in the conductive polymer tube 24, a coil member 26 in which a thin metal wire is wound in a coil shape is covered with a thin film (for example, 20 μm thick) of a conductive polymer material 27, and a solid electrolyte is contained therein. 28 is filled. The diameter of the conductive polymer tube 24 is about 0.25 mm, and the diameter of the actuator element 23 bundled with the conductive polymer tube 24 is about 4.5 mm.

  The conductive polymer material 27 is made of, for example, one or a mixture of polypyrrole, polyaniline, polythiophene, and derivatives thereof. The solid electrolyte 28 includes a lithium salt used for the nonaqueous battery electrolyte, a solvent that dissolves the lithium salt, and a polymer matrix that holds the solvent. When a positive potential and a negative potential are applied to the conductive polymer material 27 and the solid electrolyte 28, respectively, negative ions in the solid electrolyte 28 are absorbed and expanded by the conductive polymer material 27, and conversely, the conductive polymer material 27. When a negative potential and a positive potential are applied to the solid electrolyte 28, negative ions in the solid electrolyte 28 are released from the conductive polymer material 27 and contract. At this time, the conductive polymer material 27 can generate an expansion ratio of about 15% and an output of about 22 MPa with only a voltage of 1 V to 3 V, and stretches with a response time of about 0.2 seconds. The state and the contraction state can be switched.

  As shown in FIG. 2, the electronic control unit U to which the lateral acceleration of the vehicle detected by the lateral acceleration sensor 29 is input controls the operation of the polymer actuators 18 and 18 according to the detected lateral acceleration.

  Thus, when a positive voltage is applied to the conductive polymer material 27 of the conductive polymer tube 24 of the actuator element 23 and a negative voltage is applied to the solid electrolyte 28, the actuator element 23 extends in the longitudinal direction. At this time, the actuator element 23 spirally wound and accommodated in the cylindrical space defined by the cylinder 21 and the piston 22 cannot expand in the direction in which the diameter of the spiral increases. The polymer actuator 18 is extended while rotating in a direction to drive the piston 22 from the cylinder 21 in the direction of pushing out, and the polymer actuator 18 is extended.

  Conversely, when a negative voltage is applied to the conductive polymer material 27 of the conductive polymer tube 24 of the actuator element 23 and a positive voltage is applied to the solid electrolyte 28, the actuator element 23 contracts in the longitudinal direction. Then, the piston 22 is pushed into the cylinder 21 by the reaction force received from the rubber bush 17 and the polymer actuator 18 contracts.

  Next, a first embodiment of the present invention having the above configuration will be described.

  When the lateral acceleration sensor 29 detects a lateral acceleration of a predetermined value or more during high-speed turning of the vehicle, the electronic control unit U operates the two polymer actuators 18 and 18 of the rubber bush mount 13 in the extending direction. Then, as shown in FIG. 5 (A), the piston 22 is pushed out from the cylinder 21 of the polymer actuator 18 to compress the rubber bush 17, so that the spring constant becomes large. In other words, the rubber bush 17 becomes hard and the relative positions of the outer cylinder 14 and the inner cylinder 16 hardly change, and the rigidity of the suspension device is increased so that it can withstand the side force acting on the tire due to the lateral acceleration during high-speed turning. , Turning performance can be improved.

  On the other hand, when the lateral acceleration detected by the lateral acceleration sensor 29 becomes equal to or less than a predetermined value when the vehicle is traveling straight ahead, the electronic control unit U operates the two polymer actuators 18 and 18 of the rubber bush mount 13 in the contracting direction. Then, as shown in FIG. 2, since the piston 22 is drawn into the cylinder 21 of the polymer actuator 18 and the compression of the rubber bush 17 is released, the spring constant becomes small. That is, the rubber bush 17 becomes soft and the relative positions of the outer cylinder 14 and the inner cylinder 16 are easily changed, and vibration from the road surface is hardly transmitted to the vehicle body, thereby improving the riding comfort.

  Further, when the lateral acceleration sensor 29 detects a lateral acceleration of a predetermined value or more during high-speed turning of the vehicle, if only the polymer actuator 18 on the arm body 11 side is operated in the extending direction as shown in FIG. The inner cylinder 16 can be moved away from the arm main body 11 with respect to the outer cylinder 14 to substantially increase the length of the suspension arm 10. Conversely, as shown in FIG. 5C, when only the polymer actuator 18 on the opposite side of the arm body 11 is operated in the extending direction, the inner cylinder 16 moves in a direction closer to the arm body 11 with respect to the outer cylinder 14. Thus, the length of the suspension arm 10 can be substantially shortened.

  In this way, by adjusting the substantial length of the suspension arm 10, for example, the substantial length of the suspension arm 10 is adjusted in the direction in which the rear wheels are toe-in or the direction in which the front wheels are toe-out when turning. In addition, the vehicle can be understeered to improve the steering performance.

  As described above, since the spring constants of the rubber bush mounts 13 and 13 of the suspension arm 10 can be changed according to the motion state of the vehicle, the rigidity of the suspension device that resists the side force of the tire acting during high-speed turning. And the ride comfort when traveling straight ahead. In addition, since the operation of the electronic control unit U polymer actuators 18 and 18 is controlled in accordance with the lateral acceleration of the vehicle detected by the lateral acceleration sensor 29, the characteristics of the rubber bush mount 13 are not required for any special operation by the driver. Can be changed to characteristics suitable for the running state of the vehicle.

  In addition, the actuator element 23 in which a large number of bundles of conductive polymer tubes 24 each having a film of the conductive polymer material 27 formed around the solid electrolyte 28 are spirally wound is housed in the cylinder 21 and the piston 22. Since the polymer actuator 18 is configured as described above, it is possible to obtain a polymer actuator 18 having a simple structure and a low output while having a high output and high responsiveness as compared with a conventional one using a hydraulic cylinder.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  The rubber bush 17 of the rubber bush mount 13 of the first embodiment is provided with two polymer actuators 18 and 18 so as to sandwich the inner cylinder 16 on the axis L of the suspension arm 10. The rubber bushing 17 of the rubber bushing mount 13 includes one polymer actuator 18 on the arm body 11 side so as to sandwich the inner cylinder 16 on the axis L of the suspension arm 10, and one on the opposite side of the arm body 11. The space portion 17a is provided.

  When the polymer actuator 18 is driven to extend, as shown in FIG. 6 (A), the inner cylinder 16 that has been at the center of the outer cylinder 14 so far moves away from the arm body 11, and the suspension arm 10. The substantial length can be increased. At this time, since the space portion 17a is formed on the opposite side of the polymer actuator 18 with the inner cylinder 16 in between, the rubber bush 17 is easily deformed, and a sufficient amount of movement of the inner cylinder 16 with respect to the outer cylinder 14 is ensured. can do.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the motion state of the vehicle is detected based on the lateral acceleration, but can be detected based on the yaw rate, the vehicle speed, the steering angle, and the like.

  In addition, by detecting the waveform of the vibration input to the suspension arm 10 from the road surface and controlling the operation of the polymer actuators 18 and 18 in the direction to cancel the vibration, the vibration transmitted from the road surface to the vehicle body is absorbed. You can increase your comfort.

  In the second embodiment, the polymer actuator 18 is provided on the arm body 11 side, and the space portion 17a is provided on the opposite side of the arm body 11. However, if the positional relationship between the polymer actuator 18 and the space portion 17a is changed, the high By driving the molecular actuator 18 to extend, the inner cylinder 16 located at the center of the outer cylinder 14 can be moved in a direction approaching the arm main body 11, and the substantial length of the suspension arm 10 can be reduced.

  The structure of the polymer actuator 18 is not limited to the embodiment, and an appropriate structure can be adopted.

Front view of automobile suspension arm 2 is an enlarged sectional view of part 2 in FIG. 3 is an enlarged sectional view of part 3 in FIG. Perspective view of conductive polymer tube Action diagram when the polymer actuator operates The figure corresponding to the said FIG. 2 based on 2nd Example.

Explanation of symbols

10 Suspension arm 14 Outer cylinder 16 Inner cylinder 17 Rubber bush 18 Polymer actuator 27 Conductive polymer material 28 Solid electrolyte (electrolyte)
29 Lateral acceleration sensor (running state detection means)
U Electronic control unit (control means)

Claims (2)

In a rubber bush mount in which an outer cylinder (14) fixed to a suspension arm (10) and an inner cylinder (16) fixed to a vehicle body or a knuckle are connected by a rubber bush (17),
A polymer actuator (18) in which the conductive polymer material (27) is brought into contact with the electrolyte (28) is embedded in the rubber bush (17), and the potential of the conductive polymer material (27) is set to the electrolyte (28). The potential of the conductive polymer material (27) is elongated by raising the potential of the conductive polymer material (27), and the potential of the conductive polymer material (27) is lowered to be lower than the potential of the electrolyte (28). The rubber bush mount is characterized in that the spring constant of the rubber bush (17) is changed by extending and contracting the polymer actuator (18) by contracting. A traveling state detecting means (29) for detecting the traveling state of the vehicle, and a control means (U) for controlling the operation of the polymer actuator (18) in accordance with the traveling state of the vehicle detected by the traveling state detecting means (29). The rubber bush mount according to claim 1, comprising:

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