JP6237352B2 - Vehicle height adjustment device - Google Patents

Description

  Embodiments described herein relate generally to a vehicle height adjusting device.

  Conventionally, there is a vehicle having a suspension provided with an air spring or the like using compressed air. There is also a vehicle equipped with a vehicle height adjusting device using an air spring. The vehicle height adjusting device adjusts the height of the vehicle by supplying or discharging compressed air to or from an air spring that changes the suspension state of each wheel. In addition, an air spring can also change a spring constant by supply / exhaust of compressed air, and can contribute to the improvement of riding comfort.

  By the way, in the conventional vehicle, when raising the vehicle height, a method of raising the front wheel side and the rear wheel side alternately is common. This is because the weight distribution is different between the front wheel side and the rear wheel side, and the volume and spring constant of the air spring on the front wheel side and the air spring on the rear wheel side are different. For example, in many of the vehicles that are currently distributed, heavy components such as an engine, a transmission, and a steering mechanism are arranged on the front wheel side. That is, the vehicle weight distribution is large. On the other hand, on the rear wheel side, a part of the passenger compartment, a luggage compartment, and the like are arranged, and there are few heavy parts arranged, so the vehicle weight distribution is smaller than that on the front wheel side. Therefore, an air spring having a large capacity and spring constant is arranged on the front wheel side. On the other hand, an air spring having a smaller capacity and spring constant is disposed on the rear wheel side than on the front wheel side. As described above, when air springs having different capacities and spring constants are arranged on the front wheel side and the rear wheel side, the compressed air is simultaneously supplied from one tank, which is a compressed air supply source, so that the vehicle height on the front wheel side is increased. If the vehicle height on the rear wheel side is to be raised, the vehicle height change speed differs between the front wheel side and the rear wheel side. In some cases, the compressed air to be supplied to the front wheel side where the vehicle weight distribution is large is supplied to the rear wheel side, and the vehicle height on the front wheel side may decrease. Therefore, for example, compressed air from the tank is supplied to the front wheel side to increase the vehicle height on the front wheel side, and then the tank connection is switched to the air spring on the rear wheel side to increase the vehicle height on the rear wheel side.

JP 2002-337531 A

  As described above, the vehicle height is increased by first performing either one of the front and rear wheels and then performing the other wheel, which causes a problem that the vehicle height increase control cannot be performed quickly. Therefore, an object of the present invention is to provide a vehicle height adjustment device that can quickly execute vehicle height increase control.

  The vehicle height adjusting device according to the embodiment adjusts the front wheel tank that stores the pressure fluid supplied to the front wheel height adjusting unit that adjusts the vehicle height on the front wheel side of the vehicle body, and the vehicle height on the rear wheel side of the vehicle body. A rear-wheel tank that stores pressure fluid to be supplied to the rear-wheel vehicle height adjustment unit, a front-wheel side switching unit that switches a communication state between the front-wheel vehicle height adjustment unit and the front-wheel tank, and the rear-wheel vehicle height adjustment unit And a rear wheel side switching portion that switches a communication state between the rear wheel tank and the rear wheel tank, and a communication path that is disposed in the communication path and blocks the communication path and the communication path. Controlling the flow switching unit that switches between a communication state that determines the flow direction of the pressure fluid and the flow switching unit, the front wheel side switching unit, and the rear wheel side switching unit to communicate with the front wheel height adjustment unit Pressure fluid supply / discharge state and the rear wheel height adjustment section And a control unit for controlling the supply and discharge state of the pressure fluid. According to this aspect, since the front wheel height adjustment unit and the rear wheel height adjustment unit can be adjusted independently, regardless of the capacity and spring constant of the front wheel height adjustment unit and the rear wheel height adjustment unit, A control amount and a control pressure suitable for the adjustment unit can be set, and vehicle height adjustment control can be executed at a desired timing. Also, since the front wheel tank and the rear wheel tank exist independently, the front wheel tank should be arranged near the front wheel height adjustment section, and the rear wheel tank should be arranged near the rear wheel height adjustment section. Therefore, the supply distance of the pressure fluid to each vehicle height adjustment unit can be shortened, the flow path pressure loss when the tank pressure is released is reduced, and the vehicle height adjustment speed can be improved and stabilized.

  Further, the control unit of the vehicle height adjusting device according to the embodiment causes the flow switching unit to be in the non-communication state when the vehicle height is increased, and pressure fluid is supplied from the front wheel tank to the front wheel vehicle height adjusting unit. And a rear wheel raising process for supplying pressure fluid from the rear wheel tank to the rear wheel height adjustment unit. According to this aspect, by adjusting the outflow amount and the outflow pressure of the pressure fluid from the front wheel tank and the rear wheel tank, respectively, while maintaining the posture of the vehicle body or adjusting it to be leveled and raising it Can do. Further, by simultaneously raising the front wheel side and the rear wheel side, the processing time until the vehicle height adjustment is completed can be shortened.

  In addition, when the vehicle height is lowered, the control unit of the vehicle height adjusting device according to the embodiment sets the flow switching unit to the communication state and determines the flow direction of the pressure fluid, and the front wheel vehicle height adjusting unit The front wheel lowering process for discharging the pressure fluid from the rear wheel tank to the rear wheel tank and the rear wheel lowering process for discharging the pressure fluid from the rear wheel vehicle height adjustment unit to the front wheel tank may be executed alternately. According to this aspect, the pressure fluid can be discharged from the front wheel vehicle height adjustment unit or the rear wheel vehicle height adjustment unit only by switching the flow direction in the flow switching unit. That is, the discharge processing of the two systems of pressure fluid can be executed by a single flow switching unit without providing a fluid discharge mechanism dedicated to the front wheel height adjustment unit and a fluid discharge mechanism dedicated to the rear wheel height adjustment unit.

  In addition, the control unit of the vehicle height adjusting device according to the embodiment controls the flow switching unit after the completion of the front wheel lowering process and the rear wheel lowering process, so that the front wheel tank and the rear wheel tank The pressure fluid may be moved between the front wheel tank and the rear wheel tank to adjust the storage pressure. According to this aspect, even when the stored pressure balance between the front wheel tank and the rear wheel tank is lost due to the front wheel lowering process and the rear wheel lowering process, the front wheel tank is restored to a pressure suitable for the front wheel rising process. The rear wheel tank can be restored to a pressure suitable for the rear wheel raising process.

  In addition, the flow switching unit of the vehicle height adjusting device according to the embodiment includes an external fluid supply / exhaust port, and the control unit supplies and discharges fluid from the supply / exhaust port to connect the front wheel tank and the rear The storage pressure of at least one of the wheel tanks may be adjusted. According to this aspect, even when the storage pressure of the front wheel tank or the rear wheel tank fluctuates due to an external factor such as a temperature change, the storage pressure is restored to a pressure suitable for the front wheel raising process and the rear wheel raising process. Can be made.

  Further, the control unit of the vehicle height adjusting device according to the embodiment controls the flow switching unit after executing the front wheel raising process and the rear wheel raising process, so that the front wheel height adjusting unit is controlled from the rear wheel tank. A front wheel pressure replenishing process for supplying pressure fluid to the rear wheel pressure replenishing process or a rear wheel pressure replenishing process for supplying pressure fluid from the front wheel tank to the rear wheel vehicle height adjusting unit may be executed. According to this aspect, when the front wheel raising process is to be executed when the pressure fluid remains in the rear wheel tank after the front wheel raising process and the rear wheel raising process, the residual pressure in the rear wheel tank is used. In addition, the front wheel raising process can be executed. Similarly, when it is desired to execute the rear wheel raising process when pressure fluid remains in the front wheel tank, the rear wheel raising process can be further executed using the residual pressure in the front wheel tank.

FIG. 1 is a configuration diagram of a vehicle equipped with a vehicle height adjusting device according to an embodiment. FIG. 2 is a diagram illustrating the flow of the pressure fluid when the front wheel raising process and the rear wheel raising process are executed in the vehicle height adjusting device according to the embodiment. FIG. 3 is a diagram illustrating the flow of the pressure fluid when the front wheel lowering process is executed in the vehicle height adjusting device according to the embodiment. FIG. 4 is a diagram illustrating the flow of the pressure fluid when the rear wheel lowering process is executed in the vehicle height adjusting device according to the embodiment. FIG. 5 is a diagram illustrating the flow of the pressure fluid when the storage pressure is adjusted between the front wheel tank and the rear wheel tank in the vehicle height adjusting device according to the embodiment. FIG. 6 is a diagram illustrating the flow of pressure fluid when the rear wheel raising process is performed using the front wheel tank in the vehicle height adjusting device according to the embodiment. FIG. 7 is a diagram illustrating another configuration example of the vehicle height adjusting device according to the embodiment.

  Hereinafter, exemplary embodiments of the present invention are disclosed. The configuration of the embodiment shown below, and the operation and result (effect) brought about by the configuration are merely examples. The present invention can be realized by configurations other than those disclosed in the following embodiments, and various effects (including derivative effects) obtained by the basic configuration can be obtained.

  FIG. 1 is a configuration diagram of a vehicle 12 equipped with a vehicle height adjusting device 10 according to the embodiment. In the case of FIG. 1, illustration and description of the configuration of the vehicle 12 not related to the operation description of the vehicle height adjusting device 10 are omitted.

  For example, each of the wheels 14FR, 14FL, 14RR, and 14RL of the vehicle 12 (hereinafter may be simply referred to as “wheel 14” when the wheels are not distinguished from each other) functions as a vehicle height adjusting unit. 16FL, 16RR, and 16RL (hereinafter, when the air springs are not distinguished from each other may be simply referred to as “air spring 16”) are connected. Each air spring 16 has a function of absorbing the vibration of the vehicle 12 while changing the suspension state of the wheel 14 with respect to the vehicle body 12 a of the vehicle 12. The air springs 16FR and 16FL may be referred to as front wheel height adjustment units. In addition, the air springs 16RR and 16RL may be referred to as rear wheel height adjustment units. A known structure can be used for the air spring 16. Since the air spring 16 uses the elasticity of air, it is easier to absorb fine vibration than the metal spring. Further, by controlling the air pressure, the vehicle height can be kept constant, adjusted to a desired vehicle height, or the spring constant can be changed to a desired value.

  The air springs 16FR and 16FL, which are front wheel vehicle height adjusting parts, are connected to the front wheel tank 20 via the front wheel side switching part 18a. Similarly, the air springs 16RR and 16RL, which are rear wheel vehicle height adjusting parts, are connected to the rear wheel tank 22 via the rear wheel side switching part 18b. The front wheel tank 20 stores pressure fluid (compressed air) supplied to the air springs 16FR and 16FL in order to adjust the vehicle height on the front wheel side of the vehicle body 12a. The rear wheel tank 22 stores pressure fluid (compressed air) supplied to the air springs 16RR and 16RL in order to adjust the vehicle height on the rear wheel side of the vehicle body 12a. The front wheel side switching unit 18a includes, for example, a plurality of valves. The rear wheel side switching unit 18b includes, for example, a plurality of valves. The front wheel side switching unit 18a includes an electromagnetic control valve 24a that switches inflow and outflow of compressed air stored in the front wheel tank 20, an electromagnetic control valve 24b that switches inflow and outflow of compressed air to the air spring 16FR, and compressed air to the air spring 16FL. And an electromagnetic control valve 24c for switching between inflow and outflow. Similarly, the rear wheel switching unit 18b includes an electromagnetic control valve 26a that switches inflow and outflow of compressed air stored in the rear wheel tank 22, an electromagnetic control valve 26b that switches inflow and outflow of compressed air to and from the air spring 16RR, and an air spring. It is comprised with the electromagnetic control valve 26c which switches inflow / outflow of the compressed air with respect to 16RL. The electromagnetic control valves 24a to 24c and the electromagnetic control valves 26a to 26c each have a solenoid and a spring that are ON / OFF controlled, and both are normally closed when the solenoid is in a non-energized state. Type electromagnetic control valve.

  The front wheel side switching unit 18a and the rear wheel side switching unit 18b are communicated with each other through a communication path 28. A flow switching unit 30 that switches between a non-communication state that blocks the communication passage 28 and a communication state that connects the communication passage 28 and determines the flow direction of compressed air is disposed in the path of the communication passage 28. Yes. In the case of the example in FIG. 1, the flow switching unit 30 can select either the front wheel side or the rear wheel side to determine the flow direction of the compressed air, and can freely switch the flow direction, and drives the pump 30a. The motor 30b to be made up. For example, if the motor 30b is rotationally driven in the forward direction, the pump 30a moves the compressed air from the front wheel side to the rear wheel side. Conversely, if the motor 30b is rotationally driven in the reverse direction, the pump 30a moves the compressed air from the rear wheel side to the front wheel side. Therefore, when the motor 30b is stopped, the compressed air does not flow. That is, the flow switching unit 30 forms a non-communication state that blocks the communication path 28. On the other hand, when the motor 30b is in the driving state, the flow direction of the compressed air is determined in accordance with the driving direction, and a communication state in which the communication path 28 is communicated is formed. The rotation direction of the motor 30b may be constant, and the flow direction may be changed by switching the pump 30a itself.

  Opening / closing control of the electromagnetic control valves 24 a to 24 c and the electromagnetic control valves 26 a to 26 c and drive control of the motor 30 b are executed by the control unit 32. Each air spring 16FR, 16FL, 16RR, 16RL is equipped with a vehicle height sensor 34FR, 34FL, 34RR, 34RL for detecting the vehicle height, and detects the vehicle height at a predetermined detection cycle. The detection result is provided to the control unit 32. The control unit 32 controls each electromagnetic control valve 24a-24c, 26a-26c and the motor 30b based on the vehicle height of each wheel 14 acquired from the vehicle height sensors 34FR, 34FL, 34RR, 34RL, and each air spring. The vehicle height adjustment is executed by controlling the supply / discharge state of the compressed air with respect to 16.

  Information from the vehicle height changeover switch 36, the vehicle speed sensor 38, the pressure sensors 40, 42, and the like is input to the control unit 32. By operating the vehicle height changeover switch 36, the control unit 32 executes vehicle height increase control or vehicle height decrease control. For example, the vehicle height increase amount can be determined by the operation state (the number of operations, the operation angle, etc.) of the lift switch of the vehicle height changeover switch 36. Similarly, the vehicle height lowering amount can be determined by the operation state (number of operations, operation angle, etc.) of the lowering switch of the vehicle height changeover switch 36. In addition, the control unit 32 can perform the vehicle height control based on the information provided from the vehicle speed sensor 38, for example, when the vehicle speed is "0", that is, when the vehicle 12 is stopped. You may make it improve. Further, the control unit 32 can adjust the pressure of the front wheel tank 20 and the rear wheel tank 22 based on pressure information from the pressure sensors 40 and 42 as described later. In the case of the example shown in FIG. 1, the vehicle height adjusting device 10 is a closed type system in which compressed air circulates in the vehicle height adjusting device 10, and the circulated compressed air is not affected by outside such as temperature. And

  The vehicle height adjustment process of the vehicle height adjustment device 10 configured as described above will be described for each mode. 2 to 5 illustrate the state of the electromagnetic control valve and the flow of compressed air for each mode of the vehicle height adjustment processing in the vehicle height adjustment device 10, and the vehicle 12, the wheel 14, the control unit 32, the vehicle The high sensor 34, the vehicle height changeover switch 36, the vehicle speed sensor 38, the pressure sensor 40, etc. are not shown.

  FIG. 2 is a diagram illustrating the state of the electromagnetic control valve and the flow of compressed air when the front height raising process and the rear wheel raising process are executed in the vehicle height adjusting device 10. In this case, the front wheel raising process and the rear wheel raising process are executed simultaneously. Note that the load acting on the air springs 16FR and 16FL as the front wheel height adjustment unit and the load acting on the air springs 16RR and 16RL as the rear wheel height adjustment unit vary depending on the boarding state and the loaded state of the vehicle 12. In the case of the present embodiment, in order to simplify the description, it is assumed that there is no change in the load or that it can be ignored. The front wheel tank 20 and the rear wheel tank 22 store sufficient compressed air to raise the vehicle height of the front wheel air springs 16FR and 16FL and the rear wheel air springs 16RR and 16RL at the same speed. It shall be.

  When raising a vehicle height, the control part 32 (refer FIG. 1) stops the drive of the motor 30b, and makes the distribution | circulation state of the pump 30a a shielding state. That is, the communication path 28 is brought into a non-communication state. And the control part 32 energizes electromagnetic control valve 24a, 24b, 24c as a front-wheel raising process, and makes it an "open" state. As a result, the compressed air stored in the front wheel tank 20 is supplied to the air springs 16FR and 16FL, and the air springs 16FR and 16FL are extended in accordance with the valve opening periods of the electromagnetic control valves 24a, 24b and 24c to increase the vehicle height. To raise. Similarly, the control unit 32 energizes the electromagnetic control valves 26a, 26b, and 26c in the “open” state as the rear wheel raising process. As a result, the compressed air stored in the rear wheel tank 22 is supplied to the air springs 16RR and 16RL, and the air springs 16RR and 16RL are extended in accordance with the opening periods of the electromagnetic control valves 26a, 26b and 26c. Raise the high.

  Thus, the vehicle height of the vehicle 12 is raised to a desired height in a short time by simultaneously executing the front wheel ascent process using the front wheel tank 20 and the rear wheel ascent process using the rear wheel tank 22. Can do. Since the front wheel raising process and the rear wheel raising process can be performed at the same time, it is possible to prevent the vehicle body 12a from being tilted during the vehicle height adjustment, and to make it difficult for the passenger to feel uncomfortable during the vehicle height adjustment. Further, since the front-wheel-side air springs 16FR, 16FL and the rear-wheel-side air springs 16RR, 16RL can be adjusted independently in the front-rear direction, even if the capacity and spring constant of the front-rear air springs 16 are different due to vehicle weight distribution, A control amount and control pressure suitable for each air spring 16 can be set, and vehicle height adjustment control can be executed to equalize the vehicle height rising speed. The control unit 32 can determine the control timing of the front wheel side switching unit 18a and the rear wheel side switching unit 18b based on the vehicle height information from each vehicle height sensor 34. For example, even when the vehicle 12 is tilted on uneven terrain, the height control of the vehicle height can be realized while preventing or reducing the increase in the tilt of the vehicle 12 by controlling each air spring 16 independently. .

  By the way, when the air springs on the front wheel side and the rear wheel side are controlled to rise with a single tank as before, the tank is biased to, for example, an intermediate position between the air springs 16 on the front wheel side and the rear wheel side or any one of them. Will be placed in position. In either case, the total distance of the flow path connecting the air spring 16 and the tank becomes long. As a result, the flow path pressure loss increases, and the vehicle height adjustment speed may decrease or become unstable. On the other hand, by disposing the front wheel tank 20 and the rear wheel tank 22 separately as in this embodiment, the front wheel tank 20 can be disposed in the vicinity of the air springs 16FR and 16FL on the front wheel side. Similarly, the rear-wheel tank 22 can be disposed in the vicinity of the rear-wheel air springs 16RR and 16RL. That is, the flow path length from the front wheel tank 20 and the rear wheel tank 22 to the respective air springs 16 can be shortened, and the flow path pressure loss can be reduced. As a result, a decrease in vehicle height adjustment speed and instability can be suppressed.

  As shown in FIG. 2, when the front wheel raising process and the rear wheel raising process are executed, the flow switching unit 30 needs to block the communication path 28. As described above, the pump 30a can be substantially blocked by stopping the driving of the motor 30b. In another embodiment, one control valve for shielding the flow path may be disposed in the communication path 28, or one control valve may be disposed at the front and rear positions of the pump 30a. In this case, the communication path 28 can be more reliably shielded, and the reliability of the front wheel raising process and the rear wheel raising process can be further improved.

  FIG. 3 is a diagram illustrating a flow of compressed air when the front wheel lowering process is executed in the vehicle height adjusting device according to the embodiment. FIG. 4 is a diagram showing the flow of compressed air when the rear wheel lowering process is executed. When lowering the vehicle height, it is necessary to decompress the inside of the air spring 16 by scraping the compressed air enclosed in the air spring 16 with the pump 30a. Therefore, the control unit 32 of the vehicle height adjusting device 10 of the present embodiment controls the flow switching unit 30 to bring the communication path 28 into a communication state and determines the flow direction of the compressed air to one side. For example, the front wheel lowering process is performed in which the direction of scraping of the compressed air by the pump 30a is changed from the front wheel side to the rear wheel side of the communication passage 28 and the compressed air is discharged from the air springs 16FR and 16FL on the front wheel side to the rear wheel tank 22. . Further, a rear wheel lowering process for discharging the compressed air from the rear wheel side air springs 16RR, 16RL to the front wheel tank 20 is executed with the direction of the compressed air scraped by the pump 30a from the rear wheel side to the front wheel side of the communication passage 28. To do. The front wheel lowering process and the rear wheel lowering process are executed alternately.

  In the case of FIG. 3 showing the front wheel lowering process, the control unit 32 (see FIG. 1) deenergizes the electromagnetic control valve 24a for the front wheel lowering process and puts the electromagnetic control valves 24b and 24c in the “closed” state. To the “open” state. Further, the electromagnetic control valve 26a is energized to be in an “open” state, and the electromagnetic control valves 26b and 26c are de-energized to be in a “closed” state. Then, the control unit 32 rotates the motor 30b in the forward direction, for example, so that the flow direction of the compressed air via the pump 30a is changed from the front wheel side to the rear wheel side. That is, the communication path 28 is brought into a communication state. As a result, the compressed air sealed in the front-wheel air springs 16FR and 16FL moves through the communication path 28 toward the rear-wheel tank 22 by the scraping operation of the pump 30a, and is stored in the rear-wheel tank 22. It will be. That is, the air springs 16FR and 16FL on the front wheel side are contracted by the pump 30a in accordance with the amount of compressed air that is scraped to lower the vehicle height. The control unit 32 stops the pump 30a when the air springs 16FR, 16FL on the front wheel side are lowered to a desired vehicle height, and deenergizes the electromagnetic control valves 24a, 24b, 24c and the electromagnetic control valves 26a, 26b, 26c. The “closed” state is maintained, the storage state of the rear wheel tank 22 is maintained, and the front wheel lowering process is terminated.

  Subsequently, as shown in FIG. 4, the control unit 32 (see FIG. 1) sets the electromagnetic control valve 26 a to the “closed” state by de-energizing the electromagnetic control valves 26 b and 26 c for the rear wheel lowering process. To the “open” state. In addition, the electromagnetic control valve 24a is energized to the “open” state, and the electromagnetic control valves 24b and 24c are de-energized to the “closed” state. And the control part 32 rotates the motor 30b to a reverse direction, for example, and changes the flow direction of the compressed air via the pump 30a from the rear-wheel side to the front-wheel side. That is, the communication path 28 is brought into a communication state. As a result, the compressed air sealed in the rear-wheel air springs 16RR, 16RL moves through the communication path 28 toward the front-wheel tank 20 by the scraping operation of the pump 30a and is stored in the front-wheel tank 20. become. That is, the air springs 16RR, 16RL on the rear wheel side are contracted by the pump 30a in accordance with the amount of compressed air that is scraped, and lower the vehicle height. The control unit 32 stops the pump 30a when the rear-wheel air springs 16RR and 16RL are lowered to a desired vehicle height, and deenergizes the electromagnetic control valves 26a, 26b, and 26c and the electromagnetic control valves 24a, 24b, and 24c. The rear wheel lowering process is terminated by setting the “closed” state to maintain the storage state of the front wheel tank 20.

  As described above, the front wheel lowering process for discharging the compressed air from the front-wheel-side air springs 16FR and 16FL to the rear-wheel tank 22, and the discharge of the compressed air from the rear-wheel-side air springs 16RR and 16RL to the front-wheel tank 20 are performed. The wheel lowering process is executed alternately. As a result, it is possible to execute the front wheel lowering process and the rear wheel lowering process by one flow switching unit 30 arranged in one communication path 28, which can contribute to simplification of the structure of the vehicle height adjusting device 10 and cost reduction. . It should be noted that the front wheel lowering process and the rear wheel lowering process may each be executed once and completed, or may be executed alternately a plurality of times. When the front wheel lowering process and the rear wheel lowering process are each completed once, control is easy and the driver (passenger) can easily recognize the execution of the lowering process. On the other hand, when the front wheel lowering process and the rear wheel lowering process are alternately executed a plurality of times, it is possible to suppress an increase in the inclination of the vehicle 12 during the lowering process, and to make it difficult for the driver (passenger) to feel uncomfortable. Can do.

  By the way, when the capacity and spring constant of the air springs 16 on the front wheel side and the rear wheel side are different from each other due to the vehicle weight distribution, the front wheel tank 20 and the rear wheel are executed when the front wheel lowering process and the rear wheel lowering process as described above are executed. The storage pressure of the tank 22 is changed. That is, when the next vehicle height is to be raised, the required air pressure may be insufficient or excessive. Therefore, as shown in FIG. 5, the control unit 32 (see FIG. 1) of the vehicle height adjusting device 10 of the present embodiment controls the flow switching unit 30 to complete the front wheel lowering process after the front wheel lowering process and the rear wheel lowering process are completed. Compressed air is moved between the tank 20 and the rear wheel tank 22 to adjust the storage pressure of the front wheel tank 20 and the rear wheel tank 22.

  FIG. 5 shows an example in which the compressed air sealed in the rear wheel tank 22 is moved to the front wheel tank 20. The control unit 32 deenergizes the electromagnetic control valves 24b and 24c and the electromagnetic control valves 26b and 26c to bring them into the “closed” state, and energizes the electromagnetic control valves 24a and 26a to bring them into the “open” state. Then, for example, the motor 30b is rotated in the reverse direction to change the flow direction of the compressed air through the pump 30a from the rear wheel side to the front wheel side. That is, the communication path 28 is brought into a communication state. When the front wheel tank 20 and the rear wheel tank 22 return to the preset initial values based on pressure information from the pressure sensors 40 and 42 (see FIG. 1), the motor 30b is stopped and the front wheels The pressure state of the vehicle tank 20 and the rear wheel tank 22 is maintained to prepare for vehicle height adjustment processing at the next timing. In addition, what is necessary is just to reverse the rotation direction of the motor 30b, when raising the storage pressure of the tank 22 for rear wheels.

  In this manner, after the front wheel lowering process and the rear wheel lowering process are completed, the vehicle height adjusting device 10 is simplified as shown in FIG. 5 by adjusting the storage pressure of the front wheel tank 20 and the rear wheel tank 22. Even if the communication path 28 and the flow switching unit 30 are configured in a single configuration, the subsequent front wheel raising process and rear wheel raising process can be performed smoothly. In addition, the weight balance changes between the front wheel side and the rear wheel side of the vehicle 12 due to changes in the number of passengers and the load amount of the vehicle 12, and the storage pressure initially set in the front wheel tank 20 and the rear wheel tank 22 is corrected. The storage pressure can be easily adjusted even when necessary.

  Incidentally, the storage pressure of the front wheel tank 20 and the rear wheel tank 22 is set to a value sufficient to raise the vehicle height on the front wheel side and the vehicle height on the rear wheel side to desired heights. However, as described above, the weight balance changes between the front wheel side and the rear wheel side of the vehicle 12 due to fluctuations in the number of passengers and the load amount of the vehicle 12, and the stored pressure in the front wheel tank 20 or the rear wheel tank 22 is used up. However, there may be a case where the air spring 16 does not rise to the desired vehicle height. Further, when the vehicle 12 is present on an uneven terrain and is inclined, it may be desired to raise either the front wheel side or the rear wheel side further than the standard vehicle height increase amount. The control unit 32 of the vehicle height adjusting device 10 according to the present embodiment replenishes the front wheel pressure to supply compressed air from the rear wheel tank 22 to the air springs 16FR and 16FL on the front wheel side after executing the front wheel raising process and the rear wheel raising process. Processing or rear wheel pressure replenishment processing for supplying pressure fluid from the front wheel tank 20 to the air springs 16RR and 16RL on the rear wheel side can be executed. That is, if the rear wheel tank 22 has a residual storage pressure after the front wheel raising process is executed using the storage pressure of the front wheel tank 20 and the front wheel raising process is to be further executed, The front wheel ascending process is continuously executed using the pressure. On the contrary, if the storage pressure of the rear wheel tank 22 is used up and the rear wheel raising process is executed, and there is a residual pressure in the front wheel tank 20 and the rear wheel raising process is to be further executed, The rear wheel ascending process is continuously executed using the residual storage pressure.

  For example, the rear wheel side may require more compressed air than expected to raise the vehicle height to a desired height due to an increase in the number of passengers and an increase in the load. FIG. 6 is a diagram for explaining the flow of compressed air when the rear wheel pressure replenishment process is executed for the rear wheel air springs 16RR and 16RL using the residual pressure in the front wheel tank 20 in such a case. is there.

  The control unit 32 deenergizes the electromagnetic control valve 26a to “close” and energizes the electromagnetic control valves 26b and 26c to “open”. In addition, the electromagnetic control valves 24b and 24c are deenergized to be in a “closed” state, and the electromagnetic control valve 24a is energized to be in an “open” state. In this state, the motor 30b is rotated in the forward direction, for example, and the flow of compressed air is changed from the front wheel side to the rear wheel side by the pump 30a. As a result, the residual pressure in the front wheel tank 20 is supplied to the rear wheel air springs 16RR, 16RL, and the rear wheel pressure replenishment process can be executed. In addition, what is necessary is just to reverse the rotation direction of the motor 30b, and the open / close state of each electromagnetic control valve 24,26 when performing a front wheel pressure replenishment process. Thus, the final vehicle height of the air springs 16FR, 16FL, 16RR, and 16RL can be easily adjusted to a desired height by performing the front wheel pressure replenishment process and the rear wheel pressure replenishment process.

  FIG. 7 is a diagram illustrating a vehicle height adjusting device 100 having another configuration. The vehicle height adjusting device 100 basically has the same configuration as that shown in FIG. 1 except that the flow switching unit 102 includes a 1WAY pump 104a, a motor 104b, and switching valves 106a to 106d and an external air supply / discharge mechanism. It is the same as the structure shown. Therefore, constituent members having substantially the same functions as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted as appropriate.

  In the case of the modification shown in FIG. 7, the electromagnetic control valves 24 and 26 in the front wheel raising process, the rear wheel raising process, the front wheel lowering process, the rear wheel lowering process, the adjustment of the storage pressure, the front wheel pressure supplementing process, the rear wheel pressure supplementing process, etc. The opening / closing operation is the same. On the other hand, the flow switching unit 102 requires opening / closing control of the switching valves 106a to 106d by adopting the motor 104b and the 1WAY pump 104a that are ON / OFF controlled by the control unit 32 by the relay 104c. The switching valves 106a to 106d are, for example, normally closed electromagnetic control valves. As described above, the flow switching unit 102 includes the exhaust control valve 108, the 1WAY pump 104a with the intake mode, the dryer 110, the orifice 112, the check valves 114, 116, and the like as the external air supply / discharge mechanism. The exhaust control valve 108 is a normally closed electromagnetic control valve.

  Hereinafter, the operation of the flow switching unit 102 in each control mode will be described. In each control mode described above, that is, in the front wheel raising process, the rear wheel raising process, the front wheel lowering process, the rear wheel lowering process, the adjustment of the storage pressure, the front wheel pressure replenishing process, and the rear wheel pressure replenishing process, Inhalation mode.

  In the case of the front wheel raising process and the rear wheel raising process, the communication path 28 needs to be in a non-communication state. Therefore, the control unit 32 puts the switching valves 106a to 106d in a “closed” state by de-energizing them. In this state, the front wheel raising process and the rear wheel raising process can be executed as in the example of FIG. In this case, since there is no flow of compressed air in the flow switching unit 102, the 1WAY pump 104a and the motor 104b are stopped. Further, although the exhaust control valve 108 may be in an “open” state or a “closed” state, it is desirable to reduce the chance of the inside of the flow switching unit 102 coming into contact with the outside air.

  Next, in the case of the front wheel lowering process, the switching valve 106a is in the “open” state and the switching valve 106b in order to form a flow path for scraping the compressed air enclosed in the air springs 16FR and 16FL by the 1WAY pump 104a. Is in the “closed” state, the switching valve 106c is in the “closed” state, the switching valve 106d is in the “open” state, and the exhaust control valve 108 is in the “closed” state. As a result, the compressed air sealed in the air springs 16FR and 16FL passes through the switching valve 106a, the 1WAY pump 104a, the check valve 116, the dryer 110, the orifice 112, and the switching valve 106d in this order and is sent to the rear wheel tank 22. It is. As a result, the same process as the front wheel lowering process shown in FIG. 3 can be executed. In this case, since the compressed air sealed in the air springs 16FR and 16FL passes through the dryer 110 in the process of moving to the rear wheel tank 22, the compressed air sent to the rear wheel tank 22 is dried to a predetermined degree. The state is maintained, and corrosion and freezing due to moisture of the component parts can be suppressed.

  Similarly, in the case of the rear wheel lowering process, the switching valve 106c is in the “open” state to form a flow path for scraping the compressed air sealed in the air springs 16RR and 16RL by the 1WAY pump 104a. 106d is in the “closed” state, the switching valve 106a is in the “closed” state, the switching valve 106b is in the “open” state, and the exhaust control valve 108 is in the “closed” state. As a result, the compressed air sealed in the air springs 16RR and 16RL passes through the switching valve 106c, the 1WAY pump 104a, the check valve 116, the dryer 110, the orifice 112, and the switching valve 106b in this order and is sent to the front wheel tank 20. . As a result, a process similar to the rear wheel lowering process shown in FIG. 4 can be executed. In this case as well, since the compressed air passes through the dryer 110, the compressed air sent to the front wheel tank 20 can maintain a predetermined dry state.

  Next, the state of the flow switching unit 102 when the storage pressure is adjusted between the front wheel tank 20 and the rear wheel tank 22 after the completion of the front wheel lowering process and the rear wheel lowering process will be described. For example, when the compressed air is moved from the rear wheel tank 22 to the front wheel tank 20, the switching valve 106c is in the “open” state, the switching valve 106d is in the “closed” state, and the switching valve is the same as in the rear wheel lowering process. 106a is in the “closed” state, the switching valve 106b is in the “open” state, and the exhaust control valve 108 is in the “closed” state. As a result, the compressed air stored in the rear wheel tank 22 passes through the switching valve 106c, the 1WAY pump 104a, the check valve 116, the dryer 110, the orifice 112, and the switching valve 106b in this order and is sent to the front wheel tank 20. The storage pressure can be adjusted. Also in this case, since the compressed air passes through the dryer 110, the compressed air sent to the front wheel tank 20 can maintain a predetermined dry state. When the compressed air is moved from the front wheel tank 20 to the rear wheel tank 22, the switching valve 106a is in the “open” state, the switching valve 106b is in the “closed” state, and the switching valve is the same as in the front wheel lowering process. 106c is in the “closed” state, the switching valve 106d is in the “open” state, and the exhaust control valve 108 is in the “closed” state. As a result, the compressed air stored in the front wheel tank 20 passes through the switching valve 106a, the 1WAY pump 104a, the check valve 116, the dryer 110, the orifice 112, and the switching valve 106d in this order, and is sent to the rear wheel tank 22. The storage pressure can be adjusted. Also in this case, since the compressed air passes through the dryer 110, the compressed air sent to the front wheel tank 20 can maintain a predetermined dry state.

  Further, the flow switching unit 102 can also execute the front wheel pressure supplementing process or the rear wheel pressure supplementing process as in FIG. In this case, there are two execution modes. One is a case where the storage residual pressure of the tank on the replenishing side is higher than the sealed pressure of the air spring 16 on the replenishing side, and the 1WAY pump 104a is not passed. In this case, the switching valves 106a and 106c are set to the “open” state, the switching valves 106b and 16d are set to the “open” state, or all the switching valves 106a to 106d are set to the “open” state. In this case, the front wheel pressure replenishment process or the rear wheel pressure replenishment process becomes possible depending on the pressure difference.

  Another method is a case where compressed air is pumped through the 1WAY pump 104a when the residual pressure of the tank on the replenishing side is equal to or lower than the sealed pressure of the air spring 16 on the replenishing side. For example, in the front wheel pressure replenishment process, the switching valve 106 c is in the “open” state, the switching valve 106 d is in the “closed” state, the switching valve 106 a is in the “closed” state, the switching valve 106 b is in the “open” state, and the exhaust control valve 108. Is in the “closed” state. In this case, the front wheel pressure replenishment process for supplying the remaining pressure of the rear wheel tank 22 to the front wheel air springs 16FR and 16FL can be executed by the pressure feeding operation by the 1WAY pump 104a. Similarly, in the rear wheel pressure replenishment process, the switching valve 106a is in the “open” state, the switching valve 106b is in the “closed” state, the switching valve 106c is in the “closed” state, and the switching valve 106d is in the “open” state. The valve 108 is in the “closed” state. In this case, a rear wheel pressure replenishment process for supplying the residual pressure in the front wheel tank 20 to the rear wheel air springs 16RR and 16RL can be executed by a pressure feeding operation by the 1WAY pump 104a.

  Incidentally, the storage pressure of the front wheel tank 20 and the rear wheel tank 22 of the vehicle height adjusting device 100 may fluctuate due to the influence of the ambient temperature. For example, there may be a case where the ambient temperature becomes equal to or higher than the standard set temperature (for example, 20 ° C.), and the storage pressure of the front wheel tank 20 or the rear wheel tank 22 exceeds the set allowable pressure. In this case, it may be desirable to reduce the pressure in the vehicle height raising process because the rising speed may be higher than the set speed and the raising control may become unnatural or may give the passenger a sense of incongruity. For example, when the pressure in the front wheel tank 20 reaches a predetermined upper limit value and the pressure is reduced, the control unit 32 sets the electromagnetic control valve 24a in the “open” state and sets the electromagnetic control valves 24b and 24c in the “closed” state. Further, the switching valves 106a, 106c, and 106d are set to the “closed” state, and the switching valve 106b and the exhaust control valve 108 are set to the “open” state. As a result, the compressed air is exhausted from the front wheel tank 20 through the exhaust control valve 108, and the pressure can be reduced. In this case, since the compressed air in the dry state stored in the front-wheel tank 20 passes through the dryer 110, the dryer 110 that has absorbed moisture by the intake of outside air described below can be dried and regenerated.

  Similarly, when the pressure in the rear wheel tank 22 reaches a predetermined upper limit value and the pressure is reduced, the control unit 32 sets the electromagnetic control valve 26a in the “open” state and sets the electromagnetic control valves 26b and 26c in the “closed” state. To do. Further, the switching valves 106c, 106a, 106b are set to the “closed” state, and the switching valve 106d and the exhaust control valve 108 are set to the “open” state. As a result, the compressed air is exhausted from the rear wheel tank 22 through the exhaust control valve 108 to reduce the pressure, and the dryer 110 can be dried and regenerated.

  On the other hand, when the ambient temperature becomes lower than the standard set temperature (for example, 20 ° C.), for example, below freezing point, the storage pressure of the front wheel tank 20 or the rear wheel tank 22 may be lower than the set allowable pressure. . In this case, during the vehicle height increase process, the vehicle may not be able to increase to the desired vehicle height, the increase speed is slower than the set speed, and the increase control may become unnatural, or the passenger may feel uncomfortable. It may be desirable to increase the pressure. For example, when the pressure in the front-wheel tank 20 increases below a predetermined lower limit value, the control unit 32 sets the electromagnetic control valve 24a in the “open” state and the electromagnetic control valves 24b and 24c in the “closed” state. Further, the switching valves 106a, 106c, and 106d are set to the “closed” state, the switching valve 106b is set to the “open” state, and the exhaust control valve 108 is set to the “closed” state. Then, the 1WAY pump 104a is switched to the intake mode so that outside air can be taken in, and the motor 104b is driven. As a result, the outside air taken in from the 1WAY pump 104a passes through the check valve 116, the dryer 110, the orifice 112, the switching valve 106b, and the electromagnetic control valve 24a, and is sent to the front wheel tank 20 by pressure. Increase the pressure.

  Similarly, when the pressure in the rear-wheel tank 22 increases below the predetermined lower limit value, the control unit 32 sets the electromagnetic control valve 26a in the “open” state and the electromagnetic control valves 26b and 26c in the “closed” state. Further, the switching valves 106c, 106a, 106b are set to the “closed” state, the switching valve 106d is set to the “open” state, and the exhaust control valve 108 is set to the “closed” state. Then, the 1WAY pump 104a is switched to the intake mode so that outside air can be taken in, and the motor 104b is driven. As a result, the outside air taken in from the 1WAY pump 104a passes through the check valve 116, the dryer 110, the orifice 112, the switching valve 106d, and the electromagnetic control valve 26a, and is pumped to the rear wheel tank 22 to be used for the rear wheel. The tank 22 is pressurized. In these cases, since the outside air passes through the dryer 110 and is dried, the air circulating in the vehicle height adjusting device 100 can maintain a predetermined dry state. Further, since the dryer 110 can regenerate the drying function at the time of decompression (exhaust) as described above, the function of the dryer 110 can be maintained.

  In addition, when executing the front wheel pressure replenishment process or the rear wheel pressure replenishment process, the control unit 32 may take in outside air and supply compressed air directly to the air spring 16 to increase the pressure (pressure replenishment). .

  The flow switching unit 102 only needs to have a configuration that can determine the flow direction and flow range of the compressed air in the communication path 28, and the same effect can be obtained. Further, the flow switching unit 102 has been described with an example in which the dryer 110, the exhaust control valve 108, and the like are provided, and the 1WAY pump 104a is provided with an intake mode. In another embodiment, the vehicle height adjusting device 100 is a closed type system in which compressed air circulates in the vehicle height adjusting device 100 as in the vehicle height adjusting device 10 shown in FIG. When the pressure fluctuation due to the change can be ignored, the dryer 110, the exhaust control valve 108, the intake mode of the 1WAY pump 104a, etc. may be omitted, and the vehicle of FIG. 1 is controlled by the control of the 1WAY pump 104a and the switching valves 106a to 106d. The same control as that of the high adjustment device 10 is possible, and the same effect can be obtained.

  In the above-described embodiments and modifications, examples in which compressed air is used as the pressure fluid have been described, but liquid pressure such as hydraulic pressure may be used as the pressure fluid. In the case of using liquid pressure, the same configuration as that of the above-described embodiment and modification can be employed, and the same effect can be obtained. When the liquid pressure varies depending on the surrounding environment, a reservoir tank may be provided in addition to the front wheel tank 20 and the rear wheel tank 22 to enable adjustment of the liquid pressure.

  Although embodiments and modifications have been described in the present invention, these are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Vehicle height adjusting device, 12 ... Vehicle, 12a ... Vehicle body, 16 ... Air spring, 18a ... Front wheel side switching part, 18b ... Rear wheel side switching part, 20 ... Front wheel tank, 22 ... Rear wheel tank, 24, DESCRIPTION OF SYMBOLS 26 ... Electromagnetic control valve, 28 ... Communication path, 30 ... Flow switching part, 30a ... Pump, 30b ... Motor, 32 ... Control part, 36 ... Vehicle height change switch, 100 ... Vehicle height adjustment apparatus, 102 ... Flow switching part.

Claims (6)

A front wheel tank that stores pressure fluid to be supplied to a front wheel height adjustment unit that adjusts the vehicle height on the front wheel side of the vehicle body;
A rear wheel tank for storing pressure fluid to be supplied to a rear wheel height adjustment unit for adjusting a vehicle height on the rear wheel side of the vehicle body;
A front wheel side switching unit that switches a communication state between the front wheel vehicle height adjustment unit and the front wheel tank; and a rear wheel side switching unit that switches a communication state between the rear wheel vehicle height adjustment unit and the rear wheel tank; A communication path for communication;
A flow switching unit that is disposed in the path of the communication path, and switches between a non-communication state that blocks the communication path and a communication state that connects the communication path and determines the flow direction of the pressure fluid;
The flow switching unit, the front wheel side switching unit, and the rear wheel side switching unit are controlled to supply and discharge pressure fluid to the front wheel height adjustment unit and supply and discharge of pressure fluid to the rear wheel height adjustment unit. A control unit for controlling the state;
A vehicle height adjustment device comprising:   The control unit, when raising the vehicle height, sets the flow switching unit in the non-communication state and supplies a front wheel raising process for supplying pressure fluid from the front wheel tank to the front wheel vehicle height adjustment unit, and the rear wheel The vehicle height adjusting device according to claim 1, wherein a rear wheel raising process for supplying a pressure fluid from a tank to the rear wheel vehicle height adjusting unit is simultaneously performed.   When the vehicle height is lowered, the control unit sets the flow switching unit to the communication state and determines a flow direction of the pressure fluid, and discharges the pressure fluid from the front wheel height adjustment unit to the rear wheel tank. The vehicle height adjusting device according to claim 1 or 2, wherein a front wheel lowering process and a rear wheel lowering process for discharging the pressure fluid from the rear wheel vehicle height adjusting unit to the front wheel tank are alternately executed.   The control unit controls the flow switching unit after the front wheel lowering process and the rear wheel lowering process are completed, and moves the pressure fluid between the front wheel tank and the rear wheel tank to perform the front wheel use. The vehicle height adjusting device according to claim 3, wherein a storage pressure of the tank and the rear wheel tank is adjusted. The flow switching unit has an external fluid supply / exhaust port,
5. The control unit according to claim 1, wherein the control unit adjusts a storage pressure of at least one of the front wheel tank and the rear wheel tank by supplying and discharging fluid from the supply and discharge port. Vehicle height adjustment device.   The control unit controls the flow switching unit after executing the front wheel raising process and the rear wheel raising process, and supplies a pressure fluid from the rear wheel tank to the front wheel height adjusting unit. The vehicle height adjusting device according to claim 2, wherein a rear wheel pressure replenishing process for supplying a pressure fluid from the front wheel tank to the rear wheel vehicle height adjusting unit is executed.

Images