JP2006117213A - Vehicle suspension device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a measure against heat generation of a motor of an electromagnetic suspension in a vehicle suspension device equipped with a fluid spring and the electromagnetic suspension. <P>SOLUTION: An air spring 16 is interposed between the sprung and the unsprung of the vehicle, and generates an elastic force between the sprung and the unsprung by an air chamber filled up with an air. The electromagnetic suspension 18 is equipped with the motor 22 disposed in the air chamber 72, a rod 42 and an outer shell 50 extendingly/contractingly controlled by the motor 22, and generates the damping force between the sprung and the unsprung. A heat shielding plate 20 is provided around the motor 22. The heat shielding plate 20 is extended to the outside of the air chamber 72, and heat sinks 78, 80 are provided on the extended part. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates generally to vehicle suspension devices, and more particularly to vehicle suspension devices that include both electromagnetic suspensions and fluid spring devices.

Various types of vehicle suspension systems have been developed in the past that relieve the impact transmitted from the wheels traveling on the road surface to the vehicle body. Among them, an electromagnetic suspension in which the function of the absorber is replaced with an electromagnetic actuator is known. For example, Patent Document 1 discloses an active suspension device for vehicle electric power that combines an electromagnetic suspension and an air spring.
Japanese Patent Laid-Open No. 2-120113

  However, in the suspension device having the structure as described in Patent Document 1, since the motor of the electromagnetic suspension is disposed inside the air spring, the diaphragm of the air spring is deteriorated by the heat generation of the motor, and the life of the air spring may be shortened. is there.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a technique for reducing the influence of motor heat generation of an electromagnetic suspension in a vehicle suspension system including both an electromagnetic suspension and a fluid spring. .

  One embodiment of the present invention relates to a vehicle suspension apparatus. The device includes a fluid spring interposed between a sprung and unsprung portion of a vehicle and configured to generate an elastic force between the sprung and unsprung by a chamber filled with fluid, An electric damping means having an arranged motor and an expansion / contraction member controlled to expand and contract by the motor, and configured to generate a damping force between the sprung and unsprung parts. A heat shielding plate is provided around the motor.

  Here, the “fluid spring” refers to an element that exerts an elastic force by filling a sealed space with a fluid, such as an air spring or a hydraulic spring. According to this aspect, since the heat shielding plate is provided around the motor, it is possible to suppress thermal deterioration of the chamber structure such as a diaphragm due to radiant heat from the motor.

  It is preferable that the heat shielding plate extends to the outside of the chamber, and a heat radiating plate is provided in the extending portion. If it carries out like this, the heat of a heat shielding board can be thermally radiated outside efficiently.

  The fluid spring is preferably provided with a supply port and a discharge port for fluid to the chamber separately, and is provided with a circulation means for circulating the fluid in the chamber. Thereby, the heat in the chamber can be efficiently radiated to the outside.

  A discharge port may be provided in the heat shield plate, and a pipe that guides fluid near the heat shield plate to the outside of the chamber may be provided. As a result, the fluid in the vicinity of the motor is discharged to the outside, so that the heat dissipation performance is improved.

  A fan that is rotationally driven by a motor may be provided in the vicinity of the heat radiating plate. Thereby, the heat dissipation performance from a heat sink improves.

  According to the present invention, since the heat shielding plate is provided around the motor of the electric damping means, the thermal deterioration of the chamber structure due to the radiant heat from the motor is suppressed.

  FIG. 1 is a schematic view of a four-wheel vehicle 10 including a vehicle suspension device according to the present embodiment. In FIG. 1, the vehicle suspension device is shown in a plan view for the sake of simplicity. However, in an actual vehicle, an appropriate space arrangement is used in order to exert the function of the vehicle suspension device, for example, a knuckle, It is configured by combining with other parts such as a tie rod, upper arm, and lower arm in a known manner.

  A vehicle suspension device configured by combining an air spring 16 and an electromagnetic suspension 18 is mounted between the vehicle body 12 and each wheel 14 of the vehicle 10. The air spring 16 is realized by filling compressed air into an air chamber formed so as to surround a motor that is a drive source of the electromagnetic suspension 18. The compressed air in the air chamber acts as a spring and elastically supports the wheel 14 to prevent the impact of the wheel 14 from being directly transmitted to the vehicle body 12. Further, the vehicle height can be adjusted for each wheel 14 by changing the volume of the air chamber of the air spring 16. The electromagnetic suspension 18 is configured by arranging a motor as a drive source and an expansion / contraction member expanded / contracted by the motor in series. The electromagnetic suspension 18 generates a damping force between the sprung and unsprung parts of the vehicle by controlling the force of the motor. In the present specification, the position of a member supported by the air spring 16 is referred to as “sprung”, and the position of a member not supported by the air spring 16 is referred to as “unsprung”. That is, the sprung is on the vehicle body 12 side and the unsprung is on the wheel 14 side.

  The air spring 16 and the electromagnetic suspension 18 are preferably configured integrally from the viewpoint of space saving, but may be provided separately. Detailed configurations of the air spring 16 and the electromagnetic suspension 18 will be described later with reference to FIG.

  A vehicle height sensor 104 that detects the vehicle height at the wheel position is disposed in the vicinity of each wheel 14. The vehicle height sensor 104 is of a type that detects the relative distance between the vehicle body 12 and the wheels 14 by measuring the displacement of a link connecting the axle and the vehicle body, for example. A detection signal of the vehicle height sensor 104 is sent to an electronic control device 100 (hereinafter referred to as “ECU 100”) provided in the vehicle body 12.

  The vehicle body 12 is provided with an air pressure sensor 106 for detecting the air pressure in the air chamber of the air spring 16 for each wheel. The air pressure sensor 106 is of a type that measures the air pressure by electrically detecting the displacement of a thin film provided in a passage communicating with an air chamber, for example. A detection signal from the air pressure sensor 106 is sent to the ECU 100.

  The air chamber of the air spring 16 communicates with the air supply line 190. In the middle of the air supply line 190, air pressure control valves 140 are provided corresponding to the respective wheels 14. The pneumatic control valve 140 is electrically connected to the ECU 100, and can be switched between a valve open state and a valve closed state in accordance with a signal from the ECU 100. Thus, air can be supplied to the inside of the air chamber of the air spring 16 via the air supply line 190, and air can be discharged from the inside.

  The vehicle body 12 is provided with a compressor 160 for supplying compressed air to the air supply line 190. The motor 162 supplies power to the compressor 160. When the motor 162 rotates, air is taken in from the outside through the air inlet 164 and compressed by the compressor 160. The compressed air flows into the dryer 174. The dryer 174 contains a desiccant such as silica gel, and dries the air that has flowed in and supplies it to the air supply line 190.

  The vehicle body 12 may be provided with a high-pressure tank 166 that can store compressed air supplied from the compressor 160 and a high-pressure tank valve 168 that controls the flow of air into and out of the high-pressure tank. The high-pressure tank 166 is maintained at 700 to 800 kPa, for example, by sending compressed air from the compressor 160. By supplying compressed air from both the high-pressure tank 166 and the compressor 160 to the air supply line 190, the responsiveness when the air spring is increased can be improved. Therefore, if the capacity of the compressor 160 is sufficient, the high-pressure tank 166 may not be provided in the vehicle body 12.

  The air supplied from the dryer 174 flows into the air supply line 190 that communicates with the air chamber via the check valve 178. The check valve 178 opens when air is supplied from the compressor 160 side, and flows air to the air supply line 190, but closes when air from the air supply line 190 flows. A throttle 176 is provided so as to bypass the check valve 178. The air from the air supply line 190 flows into the throttle 176 and is flown into the dryer 174 after the flow velocity is reduced. By doing so, moisture absorbed by the silica gel of the dryer 174 can be reduced. The air that has passed through the dryer 174 is discharged from the silencer 172 through the exhaust valve 170 to the outside of the vehicle.

  The vehicle interior of the vehicle body 12 may be provided with a vehicle height selection device (not shown) that can select one vehicle height from vehicle heights that are predefined by a driver's switch operation. As a result, it is possible to realize traveling that meets the driver's preference. The switch information of the vehicle height selection device is also input to the ECU 100.

  ECU 100 executes control of electromagnetic suspension 18 and air spring 16 of each wheel. The ECU 100 is communicably connected to an amplifier (not shown) that supplies electric power to the motor of the electromagnetic suspension 18, and based on signals from various sensors, the electromagnetic suspension exhibits an appropriate damping force to stabilize the vehicle body. 18 is controlled.

  The ECU 100 is electrically connected to a pneumatic control valve 140, an exhaust valve 170, a high-pressure tank valve 168, and a motor 162 that drives the compressor 160. The ECU 100 appropriately outputs control signals to the control valve and the motor 162 based on signals from various sensors and switches, and controls the air spring 16 so as to exert an appropriate elastic force.

  FIG. 2 is a diagram showing the structure of the electromagnetic suspension 18 and the air spring 16 in more detail. In the present embodiment, the electromagnetic suspension 18 and the air spring 16 are integrally formed. An output shaft 36 of the motor 22 that is a drive source of the electromagnetic suspension is configured integrally with the ball screw 44. The output shaft 36 and the ball screw 44 may be coaxially coupled via a coupling. The output shaft 36 is rotatably supported by a bearing 40 inside the rod 42.

  The ball screw 44, the rod 42, the outer shell 50, and the piston 98 are arranged coaxially. The ball screw 44 forms a ball screw mechanism by sandwiching a ball screw nut 46 having a ball passage formed therein and a plurality of balls 48 circulating in the ball passage. When the ball 48 is in rolling contact between the ball screw 44 and the ball screw nut 46, the linear motion and the rotational motion are converted with high efficiency.

  The ball screw nut 46 is connected and fixed to the upper portion of the piston 98, and the piston 98 is connected coaxially to the outer shell 50. The outer shell 50 is slidably supported with respect to the outer periphery of the rod 42 by bearings 56 and 58.

  When the motor 22 rotates the output shaft 36 with electric power supplied from a battery (not shown), the ball screw 44 rotates relative to the ball screw nut 46. Then, the outer shell 50 connected to the ball screw nut 46 via the piston 98 is pushed downward with respect to the rod 42 or pulled upward. As a result, the outer shell 50 can be expanded and contracted with respect to the rod 42 and functions as an expandable member controlled by the motor 22.

  The outer shell 50 includes a dust seal 96 disposed between the outer shell 50 and the rod 42. The dust seal 96 seals between the outer shell 50 and the rod 42 to prevent foreign matters such as dust from entering the outer shell 50.

  A second attachment portion 60 is provided at the lower portion of the outer shell 50. The second attachment portion 60 is a portion attached to a lower arm (not shown) extending from the wheel 14 and plays a role of connecting the vehicle suspension device and the wheel 14.

  In this embodiment, an example in which the ball screw 44 is provided on the spring of the vehicle and the ball screw nut 46 is provided below the spring of the vehicle will be described. Conversely, the ball screw 44 is provided below the vehicle and the ball screw nut 46 is provided on the vehicle. It may be provided on the spring.

  The electromagnetic suspension 18 operates as follows. When a drive current is applied to the motor 22, the outer shell 50 actively expands and contracts to generate a damping force. When the wheel moves up and down due to external inputs such as road surface unevenness, the air spring 16 expands and contracts due to the relative movement of the rod 42 and the outer shell 50. As a result, when the ball screw 44 rotates relative to the ball screw nut 46, the output shaft 36 rotates and the motor 22 acts as a generator. At this time, the damping force can also be generated by the resistance force generated in the motor 22. Further, the ECU 100 sets a current to be applied to the motor 22 according to the vertical acceleration of the vehicle body, and adjusts the damping force. In this way, the electromagnetic suspension 18 generates a desired damping force and attenuates the vertical vibration of the vehicle body 12 caused by the air spring 16.

  Even when there is no external input, the body can be displaced in the vertical direction by rotating the ball screw 44 and changing the position of the outer shell 50 with respect to the rod 42, so the electromagnetic suspension 18 can be used for vehicle height adjustment. Can also be used.

  The air spring 16 is arranged in parallel to the electromagnetic suspension 18 and supports the weight on the spring of the vehicle 10 and suppresses vibrations and impacts from the road surface from being transmitted to the vehicle body 12 through the wheels 14 due to its elastic force. To do.

  The air spring 16 mainly includes a first attachment portion 66, a diaphragm 64, and a cover 62. The first attachment portion 66 is a portion attached to the vehicle body 12 and connects the air spring 16 and the electromagnetic suspension 18 to the vehicle body 12. The diaphragm 64 has a “J” -shaped cross section as shown in FIG. 2, and is attached so as to surround the motor 22, the rod 42 and the outer shell 50 in an annular shape. One end of the diaphragm 64 is attached to a conical cover 62 fixed to the outer periphery of the outer shell 50, and the other end is attached to the lower end of the first attachment portion 66. The diaphragm 64, the cover 62, the outer shell 50, and the first attachment portion 66 form an air chamber 72 that is a space in which air is filled around the electromagnetic suspension 18.

  The first attachment portion 66 has a supply port 70 communicating between the air supply line 190 and the air chamber 72, and air is supplied or discharged through the supply port 70.

  The lower surface of the first attachment portion 66 and the upper surface of the motor 22 of the electromagnetic suspension 18 are connected via a cushioning material 68. Since the ball screw mechanism of the electromagnetic suspension 18 is made so that the frictional force is sufficiently low, when the motor 22 moves up and down together with the first mounting portion 66, the motor 22 follows this, and the relative of the outer shell 50 to the rod 42. The position changes.

  Here, the operation at the time of adjusting the vehicle height of the air spring 16 will be described. When compressed air is supplied from the supply port 70 into the air chamber 72 and the air pressure of the air chamber 72 rises, the lower surface of the first mounting portion 66 facing the air chamber 72 is pushed up. As a result, the vehicle height of the vehicle body 12 increases. On the contrary, when the air in the air chamber 72 is discharged from the supply port 70 and the air pressure in the air chamber 72 decreases, the first mounting portion 66 is lowered due to the weight of the vehicle body 12, thereby reducing the vehicle height of the vehicle body 12. To do.

  A cylindrical heat shielding plate 20 is provided around the motor 22. The heat shielding plate 20 passes through the center of the first attachment portion 66 and extends to the outside of the air chamber 72. The heat shielding plate 20 is fixed to the first attachment portion 66 and moves with the vertical movement of the first attachment portion 66. A lid 76 is fitted on the inner periphery of the heat shielding plate 20 at the upper part of the motor 22, thereby making the air chamber 72 a sealed structure.

  Heat sinks 78 and 80 are fitted into extending portions of the heat shielding plate 20 outside the air chamber 72. FIG. 3 is a plan view of the heat shielding plate 20 and the heat radiating plates 78 and 80. As shown in the figure, the heat radiating plates 78 and 80 are provided over the entire circumference of the cylindrical heat shielding plate 20.

  The heat shielding plate 20 and the heat radiating plates 78 and 80 are preferably made of a material having high thermal conductivity, such as aluminum, but may be made of other materials. Further, the heat shielding plate 20 is not cylindrical and may have another shape. Moreover, you may provide a heat shielding board twice.

  Since the electromagnetic suspension 18 is driven at a high frequency while the vehicle is traveling, the motor 22 is likely to be hot. Therefore, by providing a heat shielding plate around the motor 22, the heat generated from the motor 22 is not directly radiated to the diaphragm 64 of the air spring 16, so that thermal deterioration of the diaphragm 64 can be suppressed. Since the diaphragm 64 is mainly made of rubber, it may be cured or cause an adhesive phenomenon at a high temperature. If the diaphragm 64 is deformed in this state, a crack or a crack is generated, and the life is shortened. Therefore, the service life of the air spring can be improved by providing the heat shielding plate as in the present embodiment.

  In addition, since the air chamber 72 is a sealed space, heat is not easily discharged, but since the heat shield plate 20 extends to the outside of the air chamber 72, the heat of the heat shield plate 20 is conducted to the outside of the air chamber 72, Since heat is radiated from the heat radiating plates 78 and 80, the heat in the air chamber 72 can be effectively discharged.

  Even when the heat shielding plate 20 does not extend to the outside of the air chamber 72 and is fixed to the lower surface of the first mounting portion 66, it is effective in that radiation to the diaphragm 64 is avoided. In this case, a heat radiating fin may be provided on the lid 76.

  Moreover, it is desirable that the first attachment portion 66 is made of a material having low thermal conductivity. This is because the first attachment portion 66 is in contact with the heat shielding plate 20, and heat may be conducted to deteriorate the attachment portion of the diaphragm 64.

  If the heat dissipation capability is insufficient with only the heat shielding plate, the air in the air chamber may be circulated. FIG. 4 is a diagram showing this state. Holes 84 and 86 having the same diameter and the same diameter are formed in the side surface of the heat shielding plate 20 and the side surface of the first mounting portion 66, and a tube 82 is fitted so as to penetrate them. A control valve 88 is connected to the outside of the air chamber of the pipe 82. The control valve 88 is electrically connected to the ECU 100 and can be switched between open and closed by a signal from an air circulation control unit (not shown) of the ECU 100.

  The air circulation control unit drives the motor 162 to supply the compressed air from the compressor 160 and the high-pressure tank 166 described in FIG. 1 into the air chamber 72 from the supply port 70, and the high-pressure tank valve 168 and the pneumatic control valve 140. Open the valve. Further, the air circulation control unit opens the control valve 88 so that the air in the air chamber 72 is released to the outside via the pipe 82. In the present embodiment, since the pipe 82 serving as the discharge port is connected to the heat shielding plate 20, the high-temperature air in the space 74 around the motor 22 can be effectively discharged outside the air chamber. it can. Instead of using the compressed air from the compressor 160 and the high-pressure tank 166 provided in the vehicle body 12, a dedicated pump for circulating the air in the air chamber 72 may be separately provided.

  In the case where it is difficult to extend the heat shielding plate 20 to the outside of the air chamber 72 due to space limitations, it is particularly effective to circulate air as described above.

  A temperature sensor for detecting the temperature in the air chamber 72 may be provided, and an air circulation control unit (not shown) may start air circulation when the temperature of the air chamber becomes a predetermined value or more. In this case, if the air pressure in the air chamber 72 is high, it is difficult to maintain a high pressure state during the air circulation. Therefore, the air circulation control unit detects when the air pressure is equal to or lower than a predetermined pressure based on the detection value by the air pressure sensor 106. Only air circulation may be started.

  As shown in FIG. 5, a fan 92 may be provided in the vicinity of the heat radiating plates 78 and 80. In this case, it is preferable to drive the fan 92 using the motor 22. As shown in FIG. 5, the structure is such that the output shaft 36 of the motor 22 projects from the top of the motor 22 as a shaft 90, and a fan 92 is fixed to the tip of the output shaft 36 with a nut 94. In this way, since the fan 92 rotates every time the electromagnetic suspension 18 is driven, heat can be radiated from the heat sinks 78 and 80, and a special drive source is not required, contributing to space saving. .

  The present invention has been described above based on the embodiment. It should be understood by those skilled in the art that these embodiments are exemplifications, and that various modifications can be made to the combination of each component and each processing process, and such modifications are also within the scope of the present invention.

  In the embodiment, the vehicle suspension apparatus in which the air spring and the electromagnetic suspension are arranged in parallel has been described. However, the present invention can also be applied to a vehicle suspension apparatus in which the hydraulic spring and the electromagnetic suspension are arranged in parallel.

It is a schematic diagram of a four-wheel vehicle provided with a vehicle suspension device. It is a figure which shows the structure of an air spring and an electromagnetic suspension. It is a top view of a heat shielding board. It is a figure which shows a mode that the fluid in an air chamber is circulated. It is a figure which shows a mode that the fan was provided in the vicinity of the heat sink.

Explanation of symbols

  10 vehicle, 12 vehicle body, 14 wheel, 16 air spring, 18 electromagnetic suspension, 20 heat shield plate, 22 motor, 64 diaphragm, 70 supply port, 72 air chamber, 78, 80 heat sink, 82 pipe, 88 control valve, 92 fan .

Claims (5)

A fluid spring interposed between the sprung and unsprung parts of the vehicle and configured to generate an elastic force between the sprung and unsprung by a chamber filled with fluid;
An electric damping means having a motor disposed in the chamber and a telescopic member controlled by the motor, and configured to generate a damping force between the sprung and unsprung;
With
A vehicle suspension device, wherein a heat shielding plate is provided around the motor.   The vehicle suspension device according to claim 1, wherein the heat shielding plate extends to the outside of the chamber, and a heat radiating plate is provided in the extending portion.   The fluid spring has a fluid supply port and a discharge port separately provided to the chamber, and further includes a circulation means for circulating the fluid in the chamber through the supply port and the discharge port. The vehicle suspension apparatus according to claim 1.   The vehicle suspension apparatus according to claim 3, wherein the discharge port is provided in the heat shielding plate, and a pipe for guiding fluid near the heat shielding plate to the outside of the chamber is provided.   The vehicle suspension device according to claim 1, wherein a fan that is rotationally driven by the motor is provided in the vicinity of the heat radiating plate.

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