JP2009298170A - Air suspension device - Google Patents

Abstract

An air suspension device that can perform vehicle body attitude control with high responsiveness and does not impair mounting properties on a vehicle.
An air suspension device 1 according to a means for solving problems of the present invention includes a pair of air springs 2 and 3 interposed between a vehicle body and an axle, a passage 4 communicating the air springs 2 and 3, and a passage 4. The cylinder 5 is provided in the middle of the cylinder 5 and is slidably inserted into the cylinder 5, and the cylinder 5 is partitioned into one chamber R 1 communicated with one air spring 2 and the other chamber R 2 communicated with the other air spring 3. The piston 6 and drive means 7 for displacing the piston 6 with respect to the cylinder 5 so as to change the volumes of the one chamber R1 and the other chamber R2 are provided.
[Selection] Figure 1

Description

  The present invention relates to an air suspension device.

  2. Description of the Related Art Conventionally, an air spring that is interposed between a vehicle body and an axle and elastically supports the vehicle body is provided in each of the four wheels and connected to an air circuit that supplies and discharges compressed air.

And the pressure of each air spring arranged on the four wheels of this vehicle is individually controlled by the air circuit, and the vehicle height can be adjusted by adjusting the pressure of the air spring through the air circuit. (For example, refer to Patent Document 1).
Japanese Patent Application Laid-Open No. 10-119531 (Embodiment of the Invention, FIG. 1)

  By the way, in the air suspension apparatus provided with the air spring, since the vehicle height can be adjusted as described above, it is considered that the vehicle body posture can be controlled by utilizing the vehicle height adjustment function.

  For example, when control is performed to suppress the roll of the vehicle body when turning the vehicle, air is supplied to the air spring arranged on the outer ring side when viewed from the turning center to increase the pressure in the air spring and tilt toward the outer ring side. It is only necessary to lift the vehicle body.

  Specifically, the roll suppression control can be realized by sensing the roll angle and the vehicle height, feeding them back, and controlling the roll angle of the vehicle body during turning to be zero.

  However, when such feedback control is actually performed using an air spring, the vibration of the vehicle body while the vehicle is traveling is converged even if the vehicle attitude is controlled by the above-described control method because air is highly compressible. This makes it difficult to oscillate body vibration.

  Further, in order to perform the attitude control as described above, it is required to adjust the vehicle height with a quick response, but when this response is required, it is necessary to increase the air supply / discharge amount to the air spring. If it does so, the air volume will become large, and the result resulting from the compressibility will become more remarkable.

  Furthermore, in order to secure a large air supply / discharge amount, an air pressure source with a large capacity is required, and the pipe connecting the air pressure source and the air spring must have a large diameter, and air is supplied to the air spring. There is also a need to separately install piping and piping for exhausting air from the air spring. If it is attempted to satisfy the above requirements, the air suspension device may be increased in size and weight, and mounting on a vehicle may be impaired.

  Therefore, the present invention was devised to improve the above-mentioned problems, and the object of the present invention is to be able to perform vehicle body attitude control with good responsiveness without impairing the mounting property on the vehicle. An air suspension device is provided.

  An air suspension device according to a means for solving problems of the present invention includes a pair of air springs interposed between a vehicle body and an axle, a passage communicating each air spring, a cylinder provided in the middle of the passage, and a slide in the cylinder. A piston that is freely inserted and divides the inside of the cylinder into one chamber communicated with one air spring and the other chamber communicated with the other air spring, and the volume of the one chamber and the other chamber is changed with respect to the cylinder. And driving means for displacing.

According to the air suspension device of the present invention, the piston is slidably inserted into the cylinder communicated with each of the air springs, instead of controlling the vehicle body posture by adjusting the vehicle height by supplying and discharging compressed air from the outside. Since the vehicle body posture control is realized simply by displacing the cylinder with respect to the cylinder, it is possible to employ a control method that is not easily affected by the compressibility of air based on the acceleration acting on the vehicle body.

  In addition, the pressure of the air spring can be adjusted without using a compressor that compresses atmospheric air and without releasing the compressed air from the air spring to the atmosphere, so there is little energy loss and the air spring pressure is adjusted simultaneously. Therefore, the response of the air spring pressure adjustment is fast, which is optimal for vehicle body posture control.

  Furthermore, there is no need to provide a large-capacity compressor, and there is no need to supply and discharge a large amount of compressed air to and from the air spring.

  Therefore, according to this air suspension device, the vehicle body posture control can be performed with good responsiveness, and the mountability on the vehicle is not impaired.

  FIG. 1 is a view showing an air suspension device according to an embodiment of the present invention.

  Hereinafter, the air suspension device 1 of the present invention will be described based on the embodiment shown in the drawings. As shown in FIG. 1, an air suspension device 1 according to an embodiment includes a pair of air springs 2 and 3 that are respectively interposed at two arbitrary locations among four locations between a vehicle wheel and a vehicle body, A passage 4 communicating with each air spring 2, 3, a cylinder 5 provided in the middle of the passage 4, and a one chamber R 1 slidably inserted into the cylinder 5 and communicated with one air spring 2 in the cylinder 5. A piston 6 that partitions into the other chamber R2 that communicates with the other air spring 3 and a drive means 7 that displaces the piston 6 relative to the cylinder 5 so as to change the volume of the one chamber R1 and the other chamber R2. Has been.

  In the case of this embodiment, the air springs 2 and 3 in the air suspension device 1 are arranged at two positions on the left and right sides in the traveling direction of the vehicle body, and in particular, to suppress a roll acting on the vehicle body. The air suspension device 1 is also provided on the rear side of the vehicle body in order to effectively suppress the roll, and the air springs 2 and 3 in the air suspension device 1 on the rear side are also in the traveling direction of the vehicle body. It is arranged at two places on the left and right.

  The air springs 2 and 3 are connected to a cylindrical chamber C connected to the vehicle body, a cylindrical air piston P connected to the vehicle body, an opening of the chamber C, and an opening of the air piston P. And a cylindrical diaphragm D that can be expanded and contracted in the vertical direction that is the axial direction, and an air chamber G that is sealed from the outside is formed by the chamber C, the air piston P, and the diaphragm D. It functions as a suspension spring that introduces compressed air to support the weight of the vehicle body.

  The air springs 2 and 3 are not limited to the above-described configuration, and may be configured so that the vehicle height can be adjusted by increasing or decreasing the internal pressure. The structure may be a balloon shape or an air cylinder shape. . The air springs 2 and 3 may be independently interposed between the four wheels of the vehicle and the vehicle body, or may be integrated with the outer periphery of a damper interposed between the wheel and the vehicle body. Also good.

  The air chambers G of the paired air springs 2 and 3 are connected by a passage 4, and a cylinder 5 is provided in the middle of the passage 4. Further, a piston 6 is slidably inserted into the cylinder 5, and the inside of the cylinder 5 is communicated with the air chamber G of one air spring 2 by the piston 6. It is partitioned off from the other chamber R2 communicated with the air chamber G.

  Further, the piston 6 can be displaced in the vertical direction in FIG. 1, which is an axial direction with respect to the cylinder 5, by the driving means 7, and by displacing the piston 6 with respect to the cylinder 5, The total volume of the chamber G and the one chamber R1 and the total volume of the air chamber G and the other chamber R2 in the air spring 3 can be changed simultaneously.

  Specifically, both ends of the cylinder 5 are closed by lids 5a and 5b. The lids 5a and 5b are annular, and a rod 6a to which the piston 6 is connected to an intermediate portion is slidably inserted on the inner peripheral side. ing. Therefore, this cylinder 5 is set to a double rod type, and in this case, the driving means 7 can displace the piston 6 from the outside of the cylinder 5 via the rod 6a.

  When the piston 6 is displaced upward in FIG. 1 with respect to the cylinder 5, the total volume of the air chamber G and the one chamber R1 in the air spring 2 is reduced and the total volume of the air chamber G and the other chamber R2 in the air spring 3 is decreased. On the contrary, when the piston 6 is displaced downward in FIG. 1 with respect to the cylinder 5, the total volume of the air chamber G and the one chamber R1 in the air spring 2 is increased and the air chamber G in the air spring 3 is increased. The total volume of the other chamber R2 can be reduced.

  Moreover, the drive means 7 should just be able to displace the piston 6 with respect to the cylinder 5, and specifically includes, for example, a motor 7a and a motion conversion mechanism 7b that converts the rotational motion of the motor 7a into a linear motion. The linear motion of the motion conversion mechanism 7b is transmitted to the piston 6 through the rod 6a to displace the piston 6.

  Specifically, the motion conversion mechanism 7b includes, for example, a feed screw mechanism including a screw shaft provided on the outer periphery of one end of the rod 6a, and a nut screwed to the screw shaft and connected to the motor 7a, or the rod 6a. A gear mechanism comprising a rack formed at one end of the worm and a worm gear meshed with the rack and connected to the motor 7a may be employed, and the piston 6 may be displaced with respect to the cylinder 5 by another mechanism. Good. Further, a reduction gear or a power transmission mechanism may be interposed between the motion conversion mechanism 7b and the motor 7a.

  Further, the driving means 7 is not limited to the above configuration as long as the airtightness in the cylinder 5 can be secured, and the driving means 7 may be built in the cylinder 5.

  As described above, in the air suspension device 1 according to the present embodiment, the volume of the air springs 2 and 3 is changed by displacing the piston 6 with respect to the cylinder 5, and the air springs 2 and 3 have the inside of the air chamber G. The pressure of can be adjusted.

  Apart from this, in this embodiment, the air springs 2, 3 installed at four locations of the vehicle are connected to the air circuit 8, and the air circuit 8 is compressed by the air springs 2, 3. Air can be supplied and discharged.

  Therefore, in the air suspension device 1, the pressure in the air chamber G in the air springs 2 and 3 can be raised by increasing the pressure in the air chamber G by supplying compressed air from the air circuit 8. On the contrary, when the air in the air chamber G is exhausted through the air circuit 8 and the pressure in the air chamber G is reduced, the vehicle body can be lowered, that is, in the air suspension device 1 of this embodiment. However, the vehicle height can be adjusted by controlling the pressure in the air chamber G in the air springs 2 and 3 by the air circuit 8 as in the conventional air suspension device.

  The air circuit 8 is not essential for the air suspension device 1 of the present invention. However, when the vehicle height changes due to a passenger or cargo, the pressure in the air chamber G is controlled by changing the weight. The vehicle height can be kept constant, and the air circuit 8 can be used for vehicle height adjustment that does not require such high responsiveness. In this case, the air springs 2 and 3 of the front and rear air suspension devices 1 are connected to the air circuit 8, and vehicle height adjustment is realized by the single air circuit 8.

  Here, the air circuit 8 only needs to be able to supply and discharge compressed air to and from the air chamber G of the air springs 2 and 3, and various configurations can be adopted. As shown in FIG. 1, the compressor 9 is extended from the discharge port 9a of the compressor 9 and branched to the air chambers G of the four air springs 2 and 3 on the front and rear of the vehicle body so that the compressor 9 communicates with the air chambers G. A supply line 10 that is connected between the compressor 9 of the supply line 10 and the air springs 2 and 3 to release the compressed air from the air chamber G of the air springs 2 and 3 to the atmosphere, and a four-branch supply line 10 is provided with an on-off valve 12 that is arranged in each of 10 and independently communicates and shuts off the compressor 9 and the air springs 2 and 3, and an exhaust valve 13 that is provided in the middle of the exhaust line 11 to open and close the exhaust line 11. Preparation It is configured.

  The on-off valve 12 is configured as a 2-port 2-position electromagnetic switching type on-off valve, and when not energized, the supply line 10 is cut off to keep the air chamber G of the air springs 2 and 3 airtight. ing. Further, the exhaust valve 13 is configured as a 2-port 2-position electromagnetic switching valve, and opens the exhaust line 11 when energized, and opens the exhaust line 11 when the pressure in the supply line 10 exceeds a predetermined pressure when de-energized. Thus, it functions as a relief valve that allows only air flow from the supply line 10 toward the atmosphere.

  Accordingly, when the compressor 9 is driven while the on-off valve 12 installed on the supply line 10 leading to the air springs 2 and 3 to be supplied with air is opened and the exhaust valve 13 is de-energized and functions as a relief valve, the compressor 9 discharges. The compressed air to be supplied is supplied into the desired air chamber G of the air springs 2 and 3, and the pressure in the gas chamber G can be increased, so that the vehicle height can be increased in view of the pressure increase.

  Further, when the opening / closing valve 12 installed on the supply line 10 leading to the air springs 2 and 3 to discharge air is opened and the exhaust valve 13 is energized to open the discharge line 11, the desired air chambers of the air springs 2 and 3 are opened. Compressed air gas is exhausted from G, the pressure in the air chamber G decreases, and the vehicle height can be lowered in accordance with the pressure decrease.

  In the case of this embodiment, the compressor 9 sucks air from the suction port 9b and supplies it to the air chamber G of the air springs 2 and 3, so that an air filter 14 is provided on the upstream side of the suction port 9b. It prevents dust and dust from entering 2 and 3. Further, the compressor 9 is driven by the motor M in the illustrated manner. However, in addition to the motor M, the compressor 9 may be driven by taking out power from an engine mounted on the vehicle. In addition, when the vehicle includes a hydraulic pump, the motor M may be a hydraulic motor instead of an electric motor.

  In the middle of the supply line 10, in order from the upstream on the discharge side of the compressor 9, a check valve 18 that prevents backflow to the compressor 9, a dryer 15 that dries the gas sent from the compressor 9, and a gas flow A restrictor 16 that provides resistance and a check valve 17 that is arranged in parallel with the restrictor 16 and that allows only a flow from the upstream side toward the downstream side are provided.

  In this case, the dryer 15 employs an adsorption type, and contains therein a desiccant that adsorbs moisture such as silica gel and activated alumina, and adsorbs moisture of the compressed gas passing through the interior with the desiccant. Thus, the compressed gas can be dried.

  In addition, the check valve 17 arranged downstream of the dryer 15 and in parallel with the throttle 16 positively allows the passage of gas in preference to the throttle 16 when the compressor 9 supplies compressed gas. It is provided so as not to cause energy loss due to the throttle 16 when supplying compressed gas.

  Further, in the case of this embodiment, when the compressed air is released from the air chamber G of the air springs 2 and 3 and released to the atmosphere, it is connected between the check valve 18 and the dryer 15 in the middle of the supply line 10. A configuration in which the air is exhausted through the exhaust line 11 is adopted, and the dryer 15 is allowed to pass through the dry compressed air filled in the air chamber G of the air springs 2 and 3.

  The throttle 16 performs a function of giving a resistance to the gas flow at the time of exhaust and abruptly reducing the pressure of the compressed air exhausted from the air springs 2 and 3 and drying the air, while allowing the gas to slowly pass through the dryer 15. 15 can be sufficiently dried. In addition, although drying of the drying agent of the dryer 15 is based on passage of a drying gas as mentioned above, you may make it employ | adopt the method of heating a drying agent separately from this. When the desiccant is dried by heating, and especially when no gas passage is required for drying the dryer 15, the air springs 2, 3 are located on the exhaust line 11 in the middle of the supply line 10 and downstream of the dryer 15. You may make it connect to the side.

  Next, the operation of the air suspension device 1 will be described. As described above, in the air suspension device 1 according to the present embodiment, the paired air springs 2 and 3 are arranged on the left and right with respect to the traveling direction of the vehicle body, and the piston 6 is displaced with respect to the cylinder 5. Thus, the volume of the air springs 2 and 3 can be changed, and the pressure in the air chamber G of the air springs 2 and 3 can be adjusted.

  Here, in the air suspension device 1, when the vehicle turns and a roll moment is applied to the vehicle body so that the outer ring side opposite to the rotation center sinks, the air spring 2 is the outer ring side and the air spring 3 is the inner ring side. Then, in order to increase the pressure of the air chamber G of the air spring 2, the piston 6 is displaced so as to decrease the volume of the one chamber R1 with respect to the cylinder 5, and the pressure in the air chamber G of the air spring 2 is increased. A reaction force that antagonizes the roll moment acting on the vehicle body is applied to the vehicle body via the air spring 2. On the contrary, the pressure in the air chamber G of the air spring 3 on the inner ring side is reduced by the displacement of the piston 6 for increasing the pressure in the air chamber G of the air spring 2 on the outer ring side. It works to lower the vehicle height on the inner ring side.

  Thus, in the air suspension device 1, the driving of the piston 6 increases the pressure of the air spring 2 on the outer ring side and decreases the pressure of the air spring 3 on the inner ring side to suppress the roll of the vehicle body. it can.

  That is, in the air suspension device 1, when the vehicle turns, the pressure in the air chamber G of the air spring 2 on the outer ring side is increased, the spring constant of the air spring 2 is increased, and the air chamber of the air spring 3 on the inner ring side is increased. By reducing the pressure in G and reducing the spring constant of the air spring 3, it is possible to increase the roll rigidity and suppress the rolling of the vehicle body, resulting in improved vehicle maneuverability and turning performance. It can be done.

  At this time, it is not necessary to supply and discharge compressed air to and from the air springs 2 and 3 by the air circuit 8, and the body posture control is completed by displacing the piston 6 in the cylinder 5 connected between the air springs 2 and 3. be able to.

  Further, in order to perform control for suppressing the roll of the vehicle body, the roll angle generated in the vehicle body is obtained, and this is fed back to control the roll angle to 0. However, the roll angle is applied to the vehicle body. In fact, the lateral acceleration acting on the vehicle body is detected, and the displacement amount of the piston 6 relative to the cylinder 5 is determined in accordance with the lateral acceleration. It may be driven according to the quantity.

  Specifically, if no control is performed, the vehicle body sinks when lateral acceleration acts on the vehicle body, and the air spring 2 on the outer ring side is compressed accordingly. On the other hand, in order to prevent the sinking of the vehicle body, the volume of the air chamber G that is reduced by the compression displacement of the air spring 2 may be returned to the state before compression. Therefore, if the piston 6 in the cylinder 5 is displaced in accordance with the reduced volume of the air chamber G so that compressed air is supplied from the cylinder 5 to the air chamber G, it will cancel out the roll moment acting on the vehicle body. Since the force can be exerted on the air spring 2 to suppress the roll of the vehicle body, the displacement of the piston 6 with respect to the cylinder 5 may be controlled in accordance with the lateral acceleration acting on the vehicle body.

  Further, in this embodiment, since the air suspension device 1 is provided before and after the vehicle body, the roll control can be performed independently before and after the vehicle body, and the roll rigidity can be adjusted independently before and after the vehicle body. The steering characteristics can be freely changed to oversteer, neutral steer and understeer.

  As described above, according to the air suspension device 1 of the present embodiment, the vehicle body posture is not controlled by adjusting the vehicle height by supplying and discharging compressed air from the outside, but communicated with each of the air springs 2 and 3. Since the vehicle body posture control is realized simply by displacing the piston 6 slidably inserted into the cylinder 5 with respect to the cylinder 5, it is difficult to be affected by the compressibility of air based on the acceleration acting on the vehicle body. The method can be adopted.

  Further, the pressure of the air springs 2 and 3 can be adjusted without using compressed air or the like from the air springs 2 and 3 without using a compressor or the like that compresses air at atmospheric pressure. Since the pressures 2 and 3 can be adjusted at the same time, the responsiveness of the pressure adjustment of the air springs 2 and 3 is fast, which is optimal for vehicle body posture control.

  Furthermore, since it is not necessary to provide a large capacity compressor and it is not necessary to supply and discharge large capacity compressed air to the air springs 2 and 3, the air suspension device 1 is not increased in size, and there is a risk that the mountability on the vehicle may be impaired. No.

  Therefore, according to the air suspension device 1, the vehicle body posture control can be performed with good responsiveness, and the mountability on the vehicle is not impaired.

  In addition, the configuration of the air suspension device 1 can be realized by adding the passage 4, the cylinder 5, the piston 6 and the driving means 7 while maintaining the circuit configuration of the conventional air suspension device. Application to the suspension device is also simplified.

  In addition, in the place mentioned above, since the air springs 2 and 3 of the air suspension apparatus 1 are arrange | positioned on the right and left with respect to the advancing direction of a vehicle body, especially a roll of a vehicle body can be suppressed, but it replaces with this arrangement | positioning. When the air springs 2 and 3 are arranged at the front and rear of the vehicle body, it is possible to perform vehicle body posture control that suppresses the pitching of the vehicle body. Furthermore, one air suspension device 1 is arranged at the left front and right rear of the vehicle body, and another If the two air suspension devices 1 are arranged at the front right and the rear left of the vehicle body, the vehicle body posture control that suppresses both the roll and the pitching of the vehicle body becomes possible. When performing control to suppress pitching, it is only necessary to detect the acceleration in the front-rear direction, determine the displacement of the piston 6 relative to the cylinder 5 based on the acceleration, and drive the piston 6.

  The driving means 7 displaces the piston 6 with respect to the cylinder 5. When the driving means 7 is stopped, the piston 6 is forcibly displaced with respect to the cylinder 5 by the action of the pressure of the air chamber G of the air springs 2 and 3. When the reversible operation is possible, the piston 6 can be freely displaced with respect to the cylinder 5 by the balance of the pressure of the air chamber G of the air springs 2 and 3. In this case, when the vehicle goes straight and passes through minute protrusions and depressions, the air springs 2 and 3 are coupled via the cylinder 5 so that the air volume of the air springs 2 and 3 is apparently large and the spring constant is low. Thus, the ride comfort in the vehicle is improved. Further, since the piston 6 is freely displaced with respect to the cylinder 5, the air spring 2 (3) on the compression side is easily contracted even on a rough road where the expansion and contraction modes of the air springs 2 and 3 are reversed. Since the air spring 3 (2) is easy to extend, the grounding property of the wheel is improved and the running performance is improved.

  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 the figure which showed the air suspension apparatus in one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air suspension apparatus 2, 3 Air spring 4 Passage 5 Cylinders 5a, 5b Cylinder lid 6 Piston 6a Rod 7 Driving means 7a Motor 7b in driving means Motion conversion mechanism 8 in driving means Air circuit 9 Compressor 9a Discharge port 9b in compressor Suction port 10 Supply line 11 Exhaust line 12 On-off valve 13 Exhaust valve 14 Air filter 15 Dryer 16 Throttle 17, 18 Check valve C Chamber D Diaphragm P Air piston G Air chamber M Motor R1 One chamber R2 Other chamber

Claims (5)

A pair of air springs interposed between the vehicle body and the axle, a passage communicating each air spring, a cylinder provided in the middle of the passage, and a slidably inserted into the cylinder so that the inside of the cylinder serves as one air spring. An air suspension apparatus comprising: a piston that partitions the one chamber communicated with the other chamber communicated with the other air spring; and a drive unit that displaces the piston relative to the cylinder so as to change the volume of the one chamber and the other chamber. . The air suspension device according to claim 1, wherein the driving means includes a motor and a motion conversion mechanism that converts the rotational motion of the motor into a linear motion, and displaces the piston. The air suspension device according to claim 1 or 2, wherein the pair of air springs are arranged on the left and right with respect to the traveling direction of the vehicle. The air suspension device according to any one of claims 1 to 3, wherein the driving means controls a displacement amount of the piston with respect to the cylinder based on a lateral acceleration of the vehicle. The air suspension device according to any one of claims 1 to 4, wherein the driving means allows reversible displacement of the piston with respect to the cylinder.

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