JP2006327295A - Air suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air suspension device capable of enhancing the ride comfort of a vehicle. <P>SOLUTION: The air suspension device is equipped with a shock absorber D and an air chamber A formed on the outside of the shock absorber D, wherein the shock absorber D is furnished with an outer cylinder 1, an inner cylinder 2 slidably inserted into the outer cylinder 1, and a motor M for generating an electromagnetic force to suppress the linear relative movement of the outer cylinder 1 with the inner 2, in which the inner cylinder side end part 1a of the outer cylinder 1 is located outside the air chamber A, and it is arranged so that the pressure in the air chamber A does not act on the inner cylinder side end part 1a, which leads to enhancement of the comfortableness in sitting in the vehicle. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improvement of an air suspension device.

  In the conventional air suspension device, for example, a hydraulic shock absorber provided with a shock absorber main body and a piston rod inserted into the shock absorber main body so as to be able to protrude and retract, and an air chamber formed on the outer peripheral side of the hydraulic shock absorber And is configured.

  The air chamber is specifically composed of a cylindrical air chamber connected to the piston rod, a cylindrical air piston connected to the shock absorber body, and a diaphragm connecting the air chamber and the air piston. It is formed and covers the outer peripheral surface of the hydraulic shock absorber (see, for example, Patent Document 1).

  The air chamber is filled with compressed air supplied from a compressor, and the air suspension device elastically supports the vehicle body weight of the vehicle by the air spring force of the compressed air in the air chamber and controls the pressure in the air chamber. The vehicle height can be adjusted by increasing or decreasing it.

That is, in this air suspension device, the compressed air filled in the air chamber functions as a suspension spring.
Japanese Patent Laid-Open No. 9-250587 (FIG. 1)

  By the way, research and development of an electromagnetic shock absorber that uses electromagnetic force as a damping force generation source (see, for example, Japanese Patent Application Laid-Open No. 2004-11750) has been conducted. In this electromagnetic shock absorber, a motor has a damping force. Since it functions not only as a generation source but also as an actuator, there is an advantage that an active suspension can be realized in a small space.

  And when considering changing the hydraulic shock absorber of the above-mentioned conventional air suspension device to an electromagnetic shock absorber, as described above, since the air chamber covering the outer peripheral surface of the shock absorber is provided, the electromagnetic shock absorber The pressure of the compressed air always acts on the seal portion that seals between the inner cylinder and the outer cylinder.

  The electromagnetic shock absorber is not filled with hydraulic oil in the space formed by the inner cylinder and the outer cylinder and the pressure in the space is not increased like the hydraulic shock absorber. Otherwise, the air chamber may communicate with the outside through the electromagnetic shock absorber, and the air spring force may not be sufficiently obtained.

  On the other hand, if the air chamber is not sealed with the above-mentioned seal part, and the electromagnetic shock absorber and the air chamber are sealed together by sealing at other locations, the heat generated by the motor is trapped inside and heat is generated. The function of the electromagnetic shock absorber may be impaired, such as demagnetization.

    Therefore, when an electromagnetic shock absorber is applied to the configuration of the conventional air suspension device, there is no other way than to employ a method of reliably sealing at the seal portion between the inner cylinder and the outer cylinder. Then, if the inner cylinder and the outer cylinder exhibit linear relative motion, a large sliding resistance is generated at the seal portion, and this sliding resistance makes the expansion and contraction operation of the air suspension device awkward and makes the ride comfort in the vehicle. There is a risk of damage.

  Accordingly, the present invention has been made to improve the above-mentioned problems, and an object of the present invention is to provide an air suspension device that improves the riding comfort in a vehicle.

  The present invention relates to an air suspension device including a shock absorber and an air chamber formed on the outer peripheral side of the shock absorber, wherein the shock absorber includes an outer cylinder, an inner cylinder that is slidably inserted into the outer cylinder, A motor that generates an electromagnetic force that suppresses linear relative motion between the outer cylinder and the inner cylinder is provided, and the inner cylinder side end of the outer cylinder is arranged outside the air chamber to solve the problem. is there.

  According to the present invention, the inner cylinder side end of the outer cylinder is disposed outside the air chamber, and the compressed air in the air chamber does not escape to the outside via the outer cylinder and the inner cylinder. It is not necessary to arrange a seal member that seals between the outer cylinder and the inner cylinder in particular.

  Therefore, in the air suspension device, the sliding resistance when the inner cylinder protrudes and retracts with respect to the outer cylinder during expansion / contraction can be reduced, so that the expansion / contraction operation of the air suspension apparatus becomes awkward and the ride comfort in the vehicle is reduced. The problem of losing is resolved.

  The present invention will be described below based on the embodiments shown in the drawings. FIG. 1 is a longitudinal sectional view of an air suspension device according to an embodiment. FIG. 2 is a longitudinal sectional view of an air suspension device according to another embodiment.

  As shown in FIG. 1, the air suspension device according to one embodiment includes a shock absorber D and an air chamber A formed on the outer peripheral side of the shock absorber D.

  Specifically, the shock absorber D includes an outer cylinder 1, an inner cylinder 2 slidably inserted into the outer cylinder 1, and an outer cylinder interposed between the outer cylinder 1 and the inner cylinder 2. 1 and a conversion mechanism 3 for converting linear relative motion of the inner cylinder 2 into rotational motion, and a motor M to which the rotational motion is transmitted.

  More specifically, the conversion mechanism 3 includes a screw shaft 4 and a ball screw nut 5 that is a screw nut that is rotatably engaged with the screw shaft 4, and the screw shaft 4 is formed on the inner periphery of the upper end of the inner cylinder 2. The ball screw nut 5 is rotatably supported by a fixed ball bearing 6, and the ball screw nut 5 is fixed to the upper end of the connecting cylinder 7 having a smaller diameter than the inner cylinder 2 connected to the lower end of the outer cylinder 1. The mechanism 3 is interposed between the outer cylinder 1 and the inner cylinder 2 as described above.

  When the outer cylinder 1 and the inner cylinder 2 exhibit a linear relative motion, the ball screw nut 5 moves linearly with respect to the screw shaft 4 to rotate the screw shaft 4, so that the conversion mechanism 3 causes the outer tube 1 to move. And the inner cylinder 2 is converted into a rotational motion from a linear relative motion.

  Further, the upper end of the screw shaft 4 is connected to the rotor 8 of the motor M fixed to the upper end of the inner cylinder 2, and the rotational movement of the screw shaft 4 is transmitted to the rotor 8. By rotating the rotor 8, an electromagnetic force is generated in the motor M, and a linear motion of the ball screw nut 5 by suppressing a rotational motion of the screw shaft 4 by a torque that resists the rotation of the rotor 8 due to the electromagnetic force. This is used as a damping force for suppressing the linear movement of the outer cylinder 1 and the inner cylinder 2.

 Although not shown in detail, the motor M includes a rotor 8 that is rotatably provided inside, and a stator (not shown) that faces the rotor 8, and specifically includes a brushless motor and the like. However, various motors such as a DC motor, an AC motor, an induction motor, and the like can be used as long as the electromagnetic force that can be used as a damping force generation source can be generated as described above.

 The motor M is connected to an external power source and a control device (not shown) so as to be able to control the rotational torque of the shaft 8 and is adjusted so as to obtain a desired damping force. By driving, this shock absorber functions not only as a shock absorber but also as an actuator.

 Further, a bearing 9 is provided between the outer cylinder 1 and the inner cylinder 2 to prevent the inner cylinder 2 from being shaken with respect to the outer cylinder 1, and between the connecting cylinder 7 and the lower end of the inner cylinder 2 in FIG. Between them, a bearing 10 is provided, which prevents shaft runout between the connecting cylinder 7 and the inner cylinder 2, and as a result, shaft runout of the screw shaft 4 with respect to the ball screw nut 5 is prevented. Further, it is possible to prevent a load from being concentrated on a part of the balls (not shown) of the ball screw nut 5 and to prevent the ball or the screw groove of the screw shaft 4 from being damaged.

 Further, since the damage to the ball or the screw groove of the screw shaft 4 can be prevented, the smooth operation of the rotation of the screw shaft 4 with respect to the ball screw nut 5 and the movement of the shock absorber in the expansion / contraction direction can be maintained. Since the smoothness of each operation can be maintained, the function as a shock absorber is not impaired, and the failure of the shock absorber can be prevented.

  Further, a dust seal S is provided between the inner circumference of the outer cylinder 1 in FIG. 1 and the outer circumference of the inner cylinder 2, and the dust seal S is a shock absorber made of the outer cylinder 1 and the inner cylinder 2. The inside is isolated from the outside of the shock absorber, and rain water, dust, and the like are prevented from entering the shock absorber.

 The connecting cylinder 7 is not necessarily formed in a cylindrical shape, and may be any one that can connect the ball screw nut 5 to the outer cylinder 1 in a state where the rotation of the ball screw nut 5 is restricted.

  Further, the bearing 10 may be omitted. Even in this case, the shaft 9 is prevented from being shaken with respect to the ball screw nut 5 by the bearing 9 described above, so there is no problem.

  Subsequently, the air chamber A connects the cylindrical air chamber 13 connected to the inner cylinder 2, the cylindrical air piston 14 connected to the outer cylinder 1, and the air chamber 13 and the air piston 14. A diaphragm 15 that is a partition wall that allows relative movement in the axial direction of the air chamber 13 and the air piston 14, and a cylinder 16 that is connected to the inner cylinder 2 and has a smaller diameter than the air piston 14 and adjacent to the outer periphery of the outer cylinder 1. And a diaphragm 17 which is an elastic partition wall connected to the cylindrical body 16 and the air piston 14.

  Describing in more detail, the cylindrical body 16 has an inner periphery at its upper end in FIG. 1 connected to an upper end in the figure of the inner cylinder 2, and its inner peripheral diameter is such that the outer cylinder 1 can be inserted. It is set so that it may become larger than the outer periphery diameter, and the collar part 161 is provided in the outer periphery. In addition, a communication hole 162 that communicates the inside and the outside of the cylinder body 16 is provided at the upper end portion.

  The air chamber 13 is formed in a bottomed cylindrical shape, and a hole 132 is opened in the bottom portion 131, and the upper end of the cylindrical body 16 is inserted into the hole 132. The flange portion 161 is connected to an annular vibration isolating rubber 18.

  The air chamber 13 is connected to a plate 20 which is annular and is coupled to the vehicle body of the vehicle via a vibration isolating rubber 19 which is welded to the upper surface of the bottom 131. The upper end of the inner cylinder 2 is described above. It can be connected to the vehicle body via the cylinder 16 and the air chamber 13.

  In this embodiment, the anti-vibration rubbers 18 and 19 are disposed on the mount portion where the air suspension device is attached to the vehicle body. However, the anti-vibration rubber 19 is eliminated and the air chamber 3 is directly attached to the vehicle body. You may make it connect. However, since the anti-vibration rubber 19 is also interposed between the air chamber 13 and the vehicle body as described above, it is possible to suppress vibrations such that the wheels get over the unevenness of the road surface as they are to the vehicle body side. It is possible.

  In the case of the present embodiment, the shock absorber D is configured such that the outer cylinder 1 is connected to a vehicle axle side member via a bracket (not shown) provided at the lower end of the outer cylinder 1 in FIG. 2 is connected to the vehicle body side member via the mount portion described above, and the motor M is arranged in the vehicle body.

  Therefore, since the motor M is not exposed to wind and rain, the reliability of the air suspension device is improved, and since the motor M is not provided between the vehicle body and the axle, the stroke length of the shock absorber can be easily secured. It is.

  On the other hand, the air piston 14 includes a cylindrical portion 141 having a diameter larger than that of the cylindrical portion 16 and an annular plate portion 142 extending from the lower end of the cylindrical portion 141. The air piston 14 is connected to the outer cylinder 1 by welding or the like on the outer periphery of the cylinder 1.

  As described above, since the diameter of the cylindrical body 16 is smaller than that of the cylindrical portion 141 of the air piston 14, the cylindrical body 16 enters the cylindrical portion 141 when the shock absorber D contracts. However, the annular plate portion 142 is attached at a position so that the lower end of the cylindrical body 16 does not contact the outer cylinder 1 during the full stroke of the shock absorber D.

  The inner periphery of the diaphragm 17 is attached to the outer periphery of the lower end of the cylindrical body 16 by a ring 25, and the outer periphery of the diaphragm 17 is attached to the inner periphery of the upper end of the cylindrical portion 141 of the air piston 14. The cylinder 16 and the air piston 14 are connected by a diaphragm 17, and the outer periphery of the diaphragm 15 is attached to the outer periphery of the lower end of the air chamber 13 by a ring 27. The inner periphery of the diaphragm 15 is attached to the outer periphery of the upper end of the cylindrical portion 141 of the piston 14 by a pressure contact with a ring 28, and the air chamber 13 and the air piston 14 are connected by the diaphragm 15.

  A guide cylinder 21 extends from the lower end of the air chamber 13, and the diaphragm 15 is provided between the guide cylinder 21 and the cylinder portion 141 of the air piston 14.

  That is, the air chamber A is annularly defined on the outer peripheral side of the shock absorber D by the air chamber 13, the air piston 14, the cylindrical body 16, and the diaphragms 15, 17, and the inner cylinder side end portion 1 a of the outer cylinder 1. Is arranged outside the air chamber A.

  Although not shown, a valve for adjusting the pressure of the compressed air in the air chamber A is provided on the side of the air chamber 13 or the like, and the compressed air is supplied from the compressor (not shown) through the valve. It is supplied into the chamber A.

  Now, the air suspension device is configured as described above, and the operation thereof will be described.

  When the shock absorber D expands and contracts, that is, when the inner cylinder 2 advances and retreats with respect to the outer cylinder 1, the air piston 14 advances and retreats in the space formed by the air chamber 13 and the cylinder body 16. Compress or expand A.

  Then, the inside of the air chamber A is pressurized or depressurized, an air spring reaction force corresponding to the degree of the pressure fluctuation is generated, and the expansion and contraction of the shock absorber D is suppressed.

  However, even in such a case, since the inner cylinder side end 1a of the outer cylinder 1 is outside the air chamber A, the inner cylinder side end is not affected by any pressure in the air chamber A. It does not affect 1a at all.

  That is, since the compressed air in the air chamber A does not escape to the outside via the outer cylinder 1 and the inner cylinder 2, a special seal is provided between the outer cylinder 1 and the inner cylinder 2 at the inner cylinder side end 1a. There is no need to distribute a sealing member.

  Therefore, in the air suspension device, the sliding resistance when the inner cylinder 2 protrudes and retracts with respect to the outer cylinder 1 during expansion and contraction can be reduced. Problems such as loss of comfort are eliminated.

  Further, in the present embodiment, the communication hole 162 is provided in the cylinder body 16, and the space R formed by the cylinder body 16, the diaphragm 17, and the air piston 14 when the shock absorber D is contracted is the communication hole. Since it is an open space that leads to the outside at 162, it is also possible to prevent pressure from acting on the dust seal S due to the compression of the gas in the space. The sliding resistance with the inner cylinder 2 can be reduced, and the riding comfort improvement effect is enhanced.

  Even if the communication hole 162 is not provided in the upper portion of the cylinder 16 but is provided, for example, in the annular plate portion 142 of the air piston 14, the riding comfort improvement effect can be enhanced as described above. Since the space R communicates with the inside of the vehicle body by being provided at the top of the vehicle body, there is an advantage that rain water, dust, dust, and the like can be prevented from entering the space R. The dust seal S itself can be omitted.

  Further, as described above, the diaphragm 15 is arranged between the guide cylinder 21 and the air piston 14, and the diaphragm 17 is arranged between the air piston 14 and the outer cylinder 1 adjacent to the cylinder 16, and the shock absorber D When the air piston 14 advances and retreats with respect to the space formed by the air chamber 13 and the cylindrical body 16 due to the expansion and contraction of the guide cylinder 21, the air piston 14 and the outer cylinder, 1 and the pressure receiving areas of the diaphragms 15 and 17 are kept substantially constant, so that the air spring force acting on the outer cylinder 1 and the inner cylinder 2 does not change suddenly, and the vehicle passenger feels uncomfortable. There is no perception.

  Further, since the motor M is fixed to the upper end of the inner cylinder 2 and is disposed at a position not covered by the air chamber A filled with air having low thermal conductivity, heat is quickly dissipated even if the motor M generates heat. Therefore, there is no fear that the motor M will cause thermal demagnetization and the like, and in this respect, the practicality and reliability of the air suspension device are improved.

  Next, an air suspension device according to another embodiment will be described. In the description of the air suspension device in the other embodiments, the same parts as those in the air suspension device in the embodiment are given the same reference numerals, and detailed description thereof is omitted, and the air suspension in the embodiment is omitted. The parts different from the suspension apparatus will be described.

  As shown in FIG. 2, the air suspension device in this other embodiment eliminates the guide cylinder 21 and the diaphragm 15 of the air suspension device in one embodiment, and instead replaces the air chamber 13 and the air piston 14 with a bellows 29. It is connected with.

  As described above, in the air suspension device according to the other embodiment, since the bellows 29 is employed, the guide at the time of expansion / contraction of the shock absorber D that has occurred in the air suspension device according to the one embodiment. Friction between the cylinder 21 and the air piston 14 and the diaphragm 15 does not occur.

  Therefore, in the air suspension device according to the other embodiment, in addition to the function and effect of the air suspension device according to the above-described one embodiment, there is no generation of the friction. There is an advantage that the ride comfort in the vehicle can be further improved.

  In the above description, the motor M is fixed to the upper end of the inner cylinder 2, but this may be fixed in the inner cylinder 2, or the inner cylinder 2 itself may function as a case of the motor M. The motor M and the screw shaft 4 may be attached to the outer cylinder 1 side, and the ball screw nut 5 may be attached to the inner cylinder 2.

  Furthermore, in the above-described embodiment, the motor M is set to a rotary type having a rotor. For example, the motor is provided with a winding on one of the inner cylinder and the outer cylinder, and a permanent magnet is appropriately disposed on the other. As a linear motor type, the linear relative motion between the inner cylinder and the outer cylinder may be suppressed using the electromagnetic force generated by the motor.

  This is the end of the description of the present invention, but it goes without saying that the scope of the present invention is not limited to the details shown or described.

It is a longitudinal cross-sectional view of the air suspension apparatus in one embodiment. It is a longitudinal cross-sectional view of the air suspension apparatus in other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Outer cylinder 1a Inner cylinder side edge part 2 Outer cylinder 3 Conversion mechanism 4 Screw shaft 5 Ball screw nut 6 Ball bearing 7 Connection cylinder 8 Rotor 9, 10 Bearing 13 Air chamber 131 Bottom part 132 Hole 14 Air piston 141 Tube part 142 Annular plate part 143 Fixing part 15, 17 Diaphragm 16 Cylinder 161 鍔 part 162 Communication hole 18, 19 Anti-vibration rubber 20 Plate 21 Guide cylinder 25, 26, 27, 28 Ring 29 Bellows A Air chamber D Buffer M Motor R Space S Dust seal

Claims (6)

In an air suspension device including a shock absorber and an air chamber formed on an outer peripheral side of the shock absorber, the shock absorber includes an outer cylinder, an inner cylinder that is slidably inserted into the outer cylinder, an outer cylinder, and an inner cylinder. An air suspension device comprising: a motor that generates an electromagnetic force that suppresses linear relative motion with a cylinder; and an inner cylinder side end portion of the outer cylinder is disposed outside the air chamber. The air chamber connects a cylindrical air chamber connected to one of the inner cylinder or the outer cylinder, a cylindrical air piston connected to the other of the inner cylinder or the outer cylinder, and the air chamber and the air piston. A partition body allowing axial movement of the air chamber and the air piston, a cylinder body connected to the inner cylinder and having a smaller diameter than the air piston, and an elastic partition wall connected to the cylinder body and the air piston are separated. The air suspension device according to claim 1, wherein the air suspension device is formed. The air suspension device according to claim 2, wherein the partition wall is a bellows. The guide cylinder extended in the edge part of an air chamber is provided, The said partition body is a diaphragm provided between the outer periphery of an air piston, and the inner periphery of a guide cylinder, The Claim 2 characterized by the above-mentioned. Air suspension device. The air suspension device according to any one of claims 2 to 4, wherein a space formed by the air piston, the cylindrical body, and the elastic partition wall is an open space. The shock absorber includes a conversion mechanism that is interposed between the inner cylinder and the outer cylinder and converts the linear motion of the inner cylinder and the outer cylinder into rotational motion, and a motor that transmits the converted rotational motion. 6. The air suspension device according to claim 1, wherein the air suspension device is characterized in that:

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