JP7156997B2 - Vehicle height adjustment device - Google Patents

Description

The present invention relates to a vehicle height adjustment device.

For example, as disclosed in Patent Document 1, a vehicle such as a tractor to which a trailer or the like is connected is equipped with a vehicle height adjustment device capable of adjusting the vehicle height. An example of a vehicle height adjustment device adjusts the vehicle height by controlling the supply and discharge of compressed air to and from a pair of left and right air springs. Such a vehicle height adjustment device is configured so that the vehicle height can be manually adjusted by operating a switch when the vehicle is connected to the trailer, and the vehicle height can be automatically adjusted when the vehicle is running.

JP-A-07-215186

One of the purposes of the vehicle height adjustment device described above is to improve convenience and safety. It is required to prohibit manual vehicle height adjustment by operation.

SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle height adjustment device capable of automatically switching between permission and prohibition of manual vehicle height adjustment by operating a switch.

A vehicle height adjustment device for solving the above problems is a vehicle height adjustment device for adjusting the vehicle height of a vehicle, comprising: a pneumatic circuit having a plurality of solenoid valves for supplying and discharging compressed air to and from an air spring; a control circuit for controlling power supply to each of the plurality of solenoid valves, wherein the control circuit is provided with a main switch that can be operated by a driver and is energized when the main switch is in an ON state. a main circuit, an elevator circuit that is provided with an elevator switch that can be operated by a driver and is configured to be energized when the main circuit is in an energized state, and power supply to the main circuit and the elevator circuit. and a power control unit that separately controls the main circuit, when the main switch is in the ON state, the power control unit acquires the vehicle speed of the vehicle, and when the vehicle speed is less than the allowable speed, the main circuit When the vehicle speed is equal to or higher than the prohibited speed which is higher than the permitted speed, the main circuit is controlled to be in the non-energized state. The main circuit is maintained in the state immediately before the vehicle speed shifts to the speed range.

According to the above configuration, the state of the main circuit is switched according to the vehicle speed when the main switch is in the ON state. Therefore, it is possible to automatically switch whether manual vehicle height adjustment by switch operation is permitted or not, that is, whether the lift switch is enabled or disabled.

In the vehicle height adjustment device, the pneumatic circuit includes an air supply path connected to an air supply source, an air supply/discharge valve provided in the air supply path, the air supply/discharge valve, and the air spring. and a supply/discharge control valve disposed in the supply/discharge path, wherein the air supply/discharge valve communicates the supply/discharge path with the air supply path in an operating state and is non-operating. A solenoid valve that communicates the supply and discharge passage with the outside in an operative state, and the supply and discharge control valve permits the flow of compressed air in the supply and discharge passage in the operative state and controls the compression in the supply and discharge passage in the non-operative state. The control circuit is configured to be able to control the air supply/discharge valve and the supply/discharge control valve to an operating state by raising the elevation switch, and lowering the elevation switch. It is preferable that the air supply/discharge valve is controlled to be inoperative and the supply/discharge control valve to be operated by operation.

According to the above configuration, when the main circuit is energized, the vehicle height can be increased by raising the lift switch. Also, the vehicle height can be lowered by lowering the lift switch.

In the vehicle height adjustment device, the pneumatic circuit includes a leveling valve for controlling supply and discharge of compressed air to and from the air spring so that the vehicle height is maintained at a predetermined set vehicle height, the air spring and the an automatic supply/discharge passage connecting a leveling valve; an automatic supply/discharge control valve, which is an air-operated valve disposed in the automatic supply/discharge passage; and an automatic supply passage connecting the leveling valve and the air supply passage. an operating pressure supply path branched from the automatic supply path and capable of supplying operating pressure to the automatic supply/discharge control valve; and a state transmission valve disposed in the operation pressure supply path, wherein the state transmission valve is an electromagnetic valve that permits the flow of compressed air in the operating pressure supply passage in an operating state to supply operating pressure to the automatic supply/discharge control valve, and the automatic supply/discharge control valve is configured to operate the automatic supply in the operating state. Compressed air is prohibited from circulating in the discharge passage and compressed air is permitted to circulate in the automatic supply/discharge passage in a non-operating state, and the control circuit operates the state transmission valve when the main circuit is in an energized state. State control is preferred.

According to the above configuration, when the main circuit is energized, the vehicle height can be adjusted by operating the lift switch, and when the main circuit is not energized, the vehicle height is automatically adjusted to the set vehicle height.

In the vehicle height adjustment device, the air spring is a first air spring, the supply/discharge passage is a first supply/discharge passage, the supply/discharge control valve is a first supply/discharge control valve, and the air pressure circuit includes a second air supply/discharge path connecting the first supply/discharge path and a second air spring; and a second supply/discharge control valve disposed in the second supply/discharge path. The path is connected to both the first supply/discharge path and the second supply/discharge path, and the automatic supply/discharge control valve controls the first supply/discharge path and the second supply/discharge path for the automatic supply/discharge path. The second air supply/discharge control valve is located closer to the leveling valve than the connecting portion of the passage, and permits the flow of compressed air in the second air supply/discharge passage in an operating state, and controls the second air supply/discharge in a non-operating state. It is advisable to prohibit the circulation of compressed air in the passageway.

According to the above configuration, since the first air spring and the second air spring communicate through the automatic supply/discharge path, compressed air can flow between the first air spring and the second air spring. As a result, the compressed air amount of the first air spring and the compressed air amount of the second air spring can be adjusted in good balance according to the load at each moment.

In the vehicle height adjustment device described above, it is preferable that the control circuit has an indicator that lights when the main circuit is in an energized state.
According to the above configuration, even if the main switch is in the ON state, the driver can be notified by the indicator whether the lift switch is valid or invalid. As a result, the driver can confirm whether the lift switch is enabled or disabled by the indicator.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a schematic configuration of a vehicle equipped with an embodiment of a vehicle height adjustment device, (a) showing a state where a trailer and a tractor are connected, and (b) before the trailer and a tractor are connected. The figure which shows the state of. 1 is a diagram showing a schematic configuration of an embodiment of a vehicle height adjustment device; FIG. FIG. 2 is a block diagram showing the configuration around an ECU; (a) A diagram showing an example of the state of the first relay during acceleration, (b) A diagram showing an example of the state of the first relay during deceleration. The figure which shows the state of a vehicle height adjustment device at the time of vehicle height automatically raising to setting vehicle height. FIG. 5 is a diagram showing the state of the vehicle height adjustment device when the vehicle height is automatically lowered to the set vehicle height; The figure which shows the state of a vehicle height adjustment device when vehicle height becomes high by raising operation. The figure which shows the state of a vehicle height adjustment device when vehicle height becomes low by descending operation.

An embodiment of a vehicle height adjustment device will be described with reference to FIGS. 1 to 8. FIG. First, referring to FIG. 1, a schematic configuration of a vehicle equipped with an embodiment of a vehicle height adjustment device will be described.
As shown in FIGS. 1(a) and 1(b), an example of the vehicle 10 is a tractor to which a trailer 11 or the like is coupled. The vehicle 10 has a vehicle body 13 having a coupler (not shown) that connects the trailer 11 and a cab 14 supported by the vehicle body 13 . The vehicle 10 has a front axle 16 that rotatably supports a pair of left and right front drive wheels 15 and a rear axle 18 that rotatably supports a pair of left and right rear drive wheels 17 . The vehicle 10 controls supply and discharge of compressed air to a pair of left and right first air springs 56 and second air springs 66 (see FIG. 2) disposed between the vehicle body 13 and the rear axle 18. has a vehicle height adjustment device 20 for adjusting the vehicle height. The vehicle height adjustment device 20 automatically adjusts the vehicle height to a predetermined set vehicle height while the vehicle is running, and is configured to be able to adjust the vehicle height by a switch operation by the driver when the trailer 11 is connected. The vehicle height adjustment device 20 has a main switch 21 and an elevation switch 22 as switches that can be operated by the driver. These various switches 21 and 22 are installed inside the cab 14 . The main switch 21 is a switch for switching ON/OFF of manual vehicle height adjustment by the driver. The lift switch 22 is a switch that can raise the vehicle height by the driver's raising operation when the main switch 21 is in the ON state, and is a switch that can lower the vehicle height by the driver's lowering operation. be.

The vehicle height adjustment device 20 also has an ECU (Electronic Control Unit) 25 that permits or prohibits vehicle height adjustment by operating the elevation switch 22 according to the state of the main switch 21 and the vehicle speed v of the vehicle 10 . . The ECU 25 functions as a power control section. The ECU 25 mainly includes an MCU (Micro Control Unit) 26 (see FIG. 3) in which a processor, a memory, an input interface, an output interface, etc. are connected to each other via a bus. A vehicle speed sensor 27 for detecting a vehicle speed v is electrically connected to the ECU 25 . The ECU 25 acquires the vehicle speed v output by the vehicle speed sensor 27 via an input interface, and disables the main switch 21 when the acquired vehicle speed v does not satisfy the permission conditions. Here, "disabling the main switch 21" means prohibiting adjustment of the vehicle height by operating the lift switch 22, assuming that the main switch 21 is in the off state even if it is in the on state. Hereinafter, the state in which the main switch 21 is disabled is referred to as the disabled state.

The vehicle height adjustment device 20 will be described in more detail with reference to FIGS. 2 to 8. FIG.
As shown in FIG. 2, the vehicle height adjustment device 20 has a control circuit 30 and a pneumatic circuit 50 in addition to the various switches 21 and 22 and the ECU 25 described above. The control circuit 30 is an electric circuit incorporating the various switches 21 and 22 and the ECU 25 described above. The control circuit 30 controls the supply of electric power to various electromagnetic valves forming the pneumatic circuit 50 according to the vehicle speed v, the state of the main switch 21 and the state of the lift switch 22 . The pneumatic circuit 50 supplies and discharges compressed air to the first air spring 56 and supplies and discharges compressed air to the second air spring 66 . 2, 3, and 5 to 8, the thick solid line indicates the wiring portion that constitutes the control circuit 30, and the thin solid line indicates the piping portion that constitutes the pneumatic circuit 50. As shown in FIG.

(Control circuit 30)
As shown in FIGS. 2 and 3 , the control circuit 30 has a power supply circuit 32 that connects the ECU 25 and a battery 31 mounted on the vehicle 10 . The control circuit 30 has a main circuit 33 connected to a power supply circuit 32 via a first relay circuit 28 built in the ECU 25 . A main switch 21 is arranged in the main circuit 33 . The main circuit 33 frame-connects the battery 31 when the main switch 21 and the first relay circuit 28 are on. That is, the main circuit 33 is energized when both the main switch 21 and the first relay circuit 28 are on, and is non-energized when one of the main switch 21 and the first relay circuit 28 is off. becomes.

The main circuit 33 has a notification circuit 34 connected in parallel with the main switch 21 . The notification circuit 34 is provided with an indicator 35 that lights up when the main circuit 33 is in an energized state. This indicator 35 is installed inside the cab 14 . The driver can grasp whether or not the vehicle height can be adjusted by operating the lifting switch 22 by turning on/off the indicator 35 .

The control circuit 30 has an elevation circuit 36 that connects the ECU 25 and the elevation switch 22 and that is connected to the power supply circuit 32 via a second relay circuit 29 incorporated in the ECU 25 . The lifting circuit 36 is an electric circuit connected to a first output port 37 provided in the ECU 25 .

The control circuit 30 has a state transmission circuit 38 that frame-connects the power supply circuit 32 via the second relay circuit 29 . A state transmission circuit 38 is an electric circuit connected to a second output port 39 provided in the ECU 25 . The state transmission circuit 38 is controlled to be energized when the second relay circuit 29 is in the ON state. Also, the state transmission circuit 38 is controlled to be in a non-energized state when the second relay circuit 29 is in the OFF state.

As shown in FIG. 2, the control circuit 30 has a first circuit 41 that frame-connects the lift circuit 36 while the lift switch 22 is operated to be raised. The control circuit 30 has a second circuit 42 that connects the lift circuit 36 through a different path from the first circuit 41 while the lift switch 22 is being lowered. The second circuit 42 is electrically connected to the first circuit 41 at a junction 43 in the first circuit 41 .

The control circuit 30 has a connection circuit 44 . The connection circuit 44 electrically connects a first electrical connection point 46 located closer to the lift switch 22 than the junction 43 in the first circuit 41 and a second electrical connection point 47 in the second circuit 42 . A diode 48 is arranged in the connection circuit 44 . Diode 48 permits conduction from first electrical connection point 46 to second electrical connection point 47 while inhibiting conduction from second electrical connection point 47 to first electrical connection point 46 .

ON/OFF of the first relay circuit 28 is controlled by the MCU 26 .
As shown in FIGS. 4(a) and 4(b), the MCU 26 turns on the first relay circuit 28 when the vehicle speed v is within the allowable range A below the allowable speed v1 (for example, 5 km/h). do. The MCU 26 disables the main switch 21 by turning off the first relay circuit 28 when the vehicle speed v is in the prohibited range C of the prohibited speed v2 (for example, 20 km/h) or higher. The MCU 26 maintains the state of the first relay circuit 28 to the state immediately before when the vehicle speed v reaches the maintenance range B of the allowable speed v1 or more and the prohibition speed v2 or less. Specifically, when the vehicle speed v reaches the maintenance range B due to acceleration, in other words, when the vehicle speed v is in the maintenance range B shifted from the allowable range A, the MCU 26 turns the first relay circuit 28 on. maintain. Conversely, when the vehicle speed v reaches the maintenance range B due to deceleration, in other words, when the vehicle speed v is in the maintenance range B shifted from the prohibited range C, the MCU 26 keeps the first relay circuit 28 in the OFF state. . That is, the MCU 26 determines that the permission condition is satisfied when the vehicle speed v is within the allowable range A and when the vehicle speed v is within the maintenance range B shifted from the allowable range A. In other words, the MCU 26 determines that the permission condition is not satisfied when the vehicle speed v is within the prohibited range C and when the vehicle speed v is within the maintenance range B shifted from the prohibited range C.

ON/OFF of the second relay circuit 29 is controlled by the MCU 26 . A signal indicating whether or not the main circuit 33 is in an energized state is input to the MCU 26 . The MCU 26 controls the second relay circuit 29 to be ON when the permission condition is satisfied and the main switch 21 is ON (the main circuit 33 is energized). The MCU 26 turns off the second relay circuit 29 not only when the permission condition is not met but also when the main switch 21 is in the off state (the main circuit 33 is not energized) even if the permission condition is met. Control. When the second relay circuit 29 is on, the vehicle height adjustment device 20 is in a manual mode in which the vehicle height is adjusted by operating the lift switch 22 . When the second relay circuit 29 is in the OFF state, the vehicle height adjustment device 20 is in an automatic mode in which the vehicle height is automatically adjusted to the set vehicle height.

(Pneumatic circuit 50)
As shown in FIG. 2, the pneumatic circuit 50 has an air supply source 51 that stores compressed air compressed by a compressor (not shown) or the like. The pneumatic circuit 50 has an air supply path 53 that connects an air supply source 51 and an air supply/discharge valve 52 . The pneumatic circuit 50 has a check valve 54 that prohibits the inflow of compressed air from the air supply path 53 to the air supply source 51 . The pneumatic circuit 50 has a first supply/discharge path 57 connecting the air supply/discharge valve 52 and the first air spring 56 . A first supply/discharge control valve 58 is arranged in the first supply/discharge path 57 .

The air supply/discharge valve 52 is a pilot-type electromagnetic valve using compressed air supplied to a pilot flow path 60 branched from the air supply path 53 at a pilot branch point 59 . The air supply/discharge valve 52 is controlled to operate when the first circuit 41 is energized. The air supply/discharge valve 52 in the operating state allows the air supply path 53 and the first supply/discharge path 57 to communicate with each other. The air supply/discharge valve 52 in the inoperative state closes the air supply path 53 and communicates the first supply/discharge path 57 with the air discharge path 61 . Compressed air that has flowed into the air discharge passage 61 is discharged from the silencer 62 to the outside.

The first supply/discharge control valve 58 is a pilot type solenoid valve that uses compressed air supplied to the pilot flow path 60 . The first supply/discharge control valve 58 is controlled to an operating state when the section between the second electrical connection point 47 and the junction 43 in the second circuit 42 is energized. The first supply/discharge control valve 58 permits the flow of compressed air between the first air spring 56 and the air supply/discharge valve 52 in the operating state, and permits the flow of compressed air between the first air spring 56 and the air supply/discharge valve 52 in the non-operating state. Prohibit the circulation of compressed air between

The pneumatic circuit 50 connects a second air spring 66 and a branch junction 65 located between the air supply/discharge valve 52 and the first supply/discharge control valve 58 in the first supply/discharge passage 57 . It has a path 67 . A second supply/discharge control valve 68 is arranged in the second supply/discharge path 67 .

The second supply/discharge control valve 68 is an air-operated valve that switches between an operating state and a non-operating state in synchronization with the first supply/discharge control valve 58 . The second supply/discharge control valve 68 is supplied with operating pressure through the pilot passage 60 when the first supply/discharge control valve 58 is in the operating state, and operates when the first supply/discharge control valve 58 is in the non-operating state. Pressure supply is cut off. The second supply/discharge control valve 68 permits the flow of compressed air between the second air spring 66 and the air supply/discharge valve 52 in the operating state, and permits the flow of compressed air between the second air spring 66 and the air supply/discharge valve 52 in the non-operating state. Prohibit the circulation of compressed air between

The pneumatic circuit 50 provides pressure to the first air spring 56 and the second air spring 66 so that the vehicle height is automatically adjusted to the set vehicle height when the valves 52, 58, 68 described above are in an inoperative state. It has a leveling valve 70 for controlling supply and discharge of compressed air. The leveling valve 70 has, for example, a lever (not shown) connected to the rear axle 18 via a link rod, and the lever is mechanically operated by changing the position of the vehicle body 13 relative to the rear axle 18 . to control the supply and discharge of compressed air.

The pneumatic circuit 50 includes an automatic supply passage 71 that is connected to a branch point 69 provided in the air supply passage 53 and connects the air supply passage 53 to the leveling valve 70 , and a first supply/discharge passage to the leveling valve 70 . 57 and an automatic supply/discharge path 72 connecting the second supply/discharge path 67 .

The pneumatic circuit 50 has an automatic supply/discharge control valve 73 in an automatic supply/discharge path 72 . The automatic supply/discharge control valve 73 is leveled at a first automatic supply/discharge point 74 that is a connection point with the first supply/discharge path 57 and a second automatic supply/discharge point 75 that is a connection point with the second supply/discharge path 67 . It is arranged at a position on the valve 70 side. The automatic supply/discharge control valve 73 is an air-operated valve that prohibits the circulation of compressed air in the automatic supply/discharge path 72 in an operating state and permits the circulation of compressed air in the automatic supply/discharge path 72 in a non-operating state.

The pneumatic circuit 50 has a branch passage 77 branching from a branch point 76 of the automatic supply passage 71 . The branch passage 77 is configured to be able to supply compressed air from the air supply passage 53 to the automatic supply/discharge control valve 73 as working fluid. The pneumatic circuit 50 has a state transfer valve 78 in the branch 77 . The state transmission valve 78 transmits the state of the state transmission circuit 38 to the automatic supply/discharge control valve 73 . The state transmission valve 78 is controlled to an operative state when the state transmission circuit 38 is in an energized state, and is controlled to be in an inoperative state when the state transmission circuit 38 is in a non-energized state. The state transmission valve 78 in the operating state supplies the operating pressure to the automatic supply/discharge control valve 73 by allowing the compressed air to flow through the branch passage 77 . The state transmission valve 78 in the non-operating state cuts off the supply of operating pressure to the automatic supply/discharge control valve 73 and connects the branch passage 77 to the air discharge passage 61 described above.

The operation of the vehicle height adjustment device 20 described above will be described with reference to FIGS. 5 to 8. FIG. In FIGS. 5 to 8, thick dotted lines indicate wiring portions in a non-energized state, and thin dotted lines indicate pipe portions through which compressed air does not flow.

(auto mode)
As shown in FIGS. 5 and 6, in the automatic mode, the vehicle height adjustment device 20 automatically adjusts the vehicle height to the set vehicle height. 5 and 6 show the main switch 21 in an off state.

In the automatic mode, the first relay circuit 28 and the second relay circuit 29 are controlled to be off. As a result, the state transmission circuit 38 is in a non-energized state, so that the state transmission valve 78 and the automatic supply/discharge control valve 73 are controlled to be in a non-operating state. Also, since the first circuit 41 and the second circuit 42 are in a non-energized state, the air supply/discharge valve 52, the first supply/discharge control valve 58, and the second supply/discharge control valve 68 are controlled to be in a non-operating state. . That is, in the automatic mode, compressed air is supplied to and discharged from the first air spring 56 and the second air spring 66 through the automatic supply/discharge path 72 .

As shown in FIG. 5, when the vehicle height increases to the set vehicle height, the compressed air from the air supply source 51 flows through the air supply passage 53, the flow dividing point 69, the automatic supply passage 71, the leveling valve 70, and the automatic supply/discharge. It is fed to the first air spring 56 and the second air spring 66 through passage 72 .

As shown in FIG. 6, when the vehicle height is lowered to the set vehicle height, the compressed air of the first air spring 56 and the second air spring 66 is discharged outside from the leveling valve 70 through the automatic supply/discharge path 72 .

(manual mode)
As shown in FIGS. 7 and 8, in the manual mode, the vehicle height adjustment device 20 adjusts the vehicle height according to the operation of the lift switch 22 by the driver. In the manual mode, the main switch 21 and the first relay circuit 28 are on, so the indicator 35 is lit. In addition, since the second relay circuit 29 is controlled to be on, the state transmission circuit 38 is energized. As a result, the state transmission valve 78 and the automatic supply/discharge control valve 73 are controlled to the operating state. That is, the supply and discharge of compressed air through the automatic supply/discharge path 72 to the first air spring 56 and the second air spring 66 is prohibited.

As shown in FIG. 7, when the lift switch 22 is lifted by the driver, the first circuit 41, the connection circuit 44, and the second circuit 42 are energized. As a result, the air supply/discharge valve 52, the first supply/discharge control valve 58, and the second supply/discharge control valve 68 are controlled to the operating state. At this time, compressed air from the air supply source 51 is supplied to the first air spring 56 through the air supply path 53 and the first supply/discharge path 57 . Compressed air from the air supply source 51 is supplied to the second air spring 66 through the air supply path 53 , the first supply/discharge path 57 , and the second supply/discharge path 67 . Thus, the vehicle height adjustment device 20 raises the vehicle height by supplying compressed air to the first air spring 56 and the second air spring 66 .

As shown in FIG. 8, when the lift switch 22 is lowered by the driver, only the second circuit 42 among the first circuit 41, the connection circuit 44, and the second circuit 42 is energized. As a result, the air supply/discharge valve 52 is controlled to be in a non-operating state, and the first supply/discharge control valve 58 and the second supply/discharge control valve 68 are controlled to be in an operating state. At this time, the compressed air of the first air spring 56 is discharged outside through the first supply/discharge path 57 , the air supply/discharge valve 52 and the air discharge path 61 . Also, the compressed air of the second air spring 66 is discharged outside through the second supply/discharge path 67 , the first supply/discharge path 57 , the air supply/discharge valve 52 , and the air discharge path 61 . Thus, the vehicle height adjustment device 20 lowers the vehicle height by discharging compressed air from the first air spring 56 and the second air spring 66 .

Effects of the present embodiment will be described.
(1) In the vehicle height adjustment device 20, the state of the main circuit 33 is switched according to the vehicle speed v even if the main switch 21 is in the ON state. Therefore, even if the main switch 21 is maintained in the ON state, it is possible to automatically switch between permission and prohibition of manual vehicle height adjustment according to the vehicle speed v.

(2) In the vehicle height adjustment device 20, when the vehicle speed v is within the allowable range A and when the vehicle speed v is within the maintenance range B shifted from the allowable range A, the vehicle height can be adjusted by operating the lift switch 22. Allowed. Therefore, even if the vehicle speed of the vehicle 10 temporarily exceeds the allowable speed v1 when the vehicle 10 is connected to the trailer 11, for example, the vehicle height adjustment by the lift switch 22 is continued. As a result, the vehicle 10 and the trailer 11 can be smoothly connected.

(3) In the vehicle height adjustment device 20, the ECU 25 acquires the vehicle speed v, but is configured so as not to require coordinated control with other ECUs. Therefore, since it is not necessary to check the cooperativeness between the ECU 25 and the other ECUs 25 in the design stage, the time required for checking the cooperativeness between the ECUs can be saved. That is, by using one ECU 25 alone, it is possible to simplify the configuration of the vehicle height adjustment device 20 and shorten the time required for designing the vehicle height adjustment device 20 .

(4) In the vehicle height adjustment device 20 , compressed air is supplied to and discharged from the first air spring 56 and the second air spring 66 through the common air supply/discharge valve 52 . Therefore, the pneumatic circuit 50 can be configured with a smaller number of valves than a configuration in which, for example, a supply valve for supplying compressed air and a discharge valve for discharging compressed air are provided for each air spring.

(5) The first supply/discharge path 57 and the second supply/discharge path 67 are connected by the automatic supply/discharge path 72 . Therefore, compressed air can flow between the first air spring 56 and the second air spring 66 through the automatic supply/discharge path 72 . As a result, the amount of compressed air in the first air spring 56 and the amount of compressed air in the second air spring 66 can be adjusted in good balance according to the load at each moment.

(6) The vehicle height adjustment device 20 can automatically adjust the vehicle height to the set vehicle height when the main circuit 33 is in the OFF state.
(7) The vehicle height adjustment device 20 has an indicator 35 that lights up when the main circuit 33 is in an energized state. Therefore, the driver can determine whether the vehicle height adjustment by the lift switch 22 is valid or invalid based on whether the indicator lights up or not.

This embodiment can be implemented with the following modifications. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
・In addition to the indicator 35, or instead of the indicator 35, the vehicle height adjustment device 20 may have a notification device that notifies the driver of whether the vehicle height adjustment by the elevation switch 22 is valid or invalid, for example, by voice. good.

- When the vehicle height adjustment device 20 has a plurality of air springs, it may have a pneumatic circuit for supplying and discharging compressed air to and from each of the plurality of air springs.
The vehicle height adjustment device 20 may have a configuration in which a set vehicle height is set by adjusting the vehicle height using the lift switch 22, or a predetermined vehicle height may be set as the set vehicle height.

- The ECU 25 may have an output port in addition to the first output port 37 and the second output port 39 . This output port preferably has a configuration in which the supply of electric power is controlled based on, for example, the vehicle speed of the vehicle, the operating state of the engine, and the like. With such a configuration, the versatility of the ECU 25 can be expanded.

DESCRIPTION OF SYMBOLS 10... Vehicle, 11... Trailer, 13... Vehicle main body, 14... Cab, 15... Front drive wheel, 16... Front axle, 17... Rear drive wheel, 18... Rear axle, 20... Vehicle height adjustment device, 21... Main switch 22 Lifting switch 25 ECU 26 MCU 27 Vehicle speed sensor 28 First relay circuit 29 Second relay circuit 30 Control circuit 31 Battery 32 Power supply circuit 33 Main circuit 34 Notification circuit 35 Indicator 36 Elevator circuit 37 First output port 38 State transmission circuit 39 Second output port 41 First circuit 42 Second circuit 43 Confluence point 44 Connection circuit 46 First electrical connection point 47 Second electrical connection point 48 Diode 50 Pneumatic circuit 51 Air supply source 52 Air supply/discharge valve 53 Air supply path 54 Check valve 56 First air spring 57 First supply/discharge path 58 First supply/discharge control valve 59 Pilot branch point 60 Pilot flow path 61 Air discharge Path 62 Silencer 65 Branch junction 66 Second air spring 67 Second supply/discharge path 68 Second supply/discharge control valve 69 Diversion point 70 Leveling valve 71 Automatic supply Path 72 Automatic supply/discharge path 73 Automatic supply/discharge control valve 74 First automatic supply/discharge point 75 Second automatic supply/discharge point 76 Branch point 77 Branch passage 78 State transmission valve .

Claims (5)

A height adjustment device for adjusting the height of a vehicle,
a pneumatic circuit having a plurality of solenoid valves for supplying and discharging compressed air to and from the air spring;
a control circuit that controls power supply to each of the plurality of solenoid valves,
The control circuit includes a main circuit that is provided with a main switch that can be operated by a driver and that is energized when the main switch is in an ON state, and a lifting switch that can be operated by the driver. an elevating circuit configured to be energized when the main circuit is in an energized state; and a power control unit that separately controls power supply to the main circuit and the elevating circuit,
When the main switch is in an ON state, the electric power control unit acquires the vehicle speed of the vehicle, controls the main circuit to be energized when the vehicle speed is less than the permitted speed, and the vehicle speed is greater than the permitted speed. When the speed is equal to or higher than the prohibition speed, the main circuit is controlled to be in a non-energized state, and when the vehicle speed is in the speed range of the permission speed or more and less than the prohibition speed, the state immediately before the vehicle speed shifts to the speed range is set. A vehicle height adjustment device that maintains the main circuit. The pneumatic circuit includes an air supply path connected to an air supply source, an air supply/discharge valve provided in the air supply path, and a supply/discharge path connecting the air supply/discharge valve and the air spring. , a supply/discharge control valve disposed in the supply/discharge path,
The air supply/discharge valve is an electromagnetic valve that communicates the supply/discharge path with the air supply path in an operating state and communicates the supply/discharge path with the outside in a non-operating state,
The supply/discharge control valve is an electromagnetic valve that permits circulation of compressed air in the supply/discharge path in an operating state and prohibits circulation of compressed air in the supply/discharge path in a non-operating state,
The control circuit is configured to be able to control the air supply/discharge valve and the supply/discharge control valve to an operating state by raising the elevation switch, and to deactivate the air supply/discharge valve by lowering the elevation switch. 2 . The vehicle height adjustment device according to claim 1 , which is configured to be able to control the supply/discharge control valve to an operating state while controlling the supply/discharge control valve to an operating state. The pneumatic circuit includes a leveling valve that controls supply and discharge of compressed air to and from the air spring so that the vehicle height is maintained at a predetermined set vehicle height, and an automatic valve that connects the air spring and the leveling valve. a supply/discharge passage, an automatic supply/discharge control valve that is an air-operated valve disposed in the automatic supply/discharge passage, an automatic supply passage that connects the leveling valve and the air supply passage, and a branch from the automatic supply passage. an operating pressure supply path capable of supplying operating pressure to the automatic supply/discharge control valve; and a state transmission valve disposed in the operating pressure supply path,
The state transmission valve is an electromagnetic valve that permits the flow of compressed air in the operating pressure supply passage in an operating state and supplies operating pressure to the automatic supply/discharge control valve,
The automatic supply/discharge control valve prohibits circulation of compressed air in the automatic supply/discharge path in an operating state and permits circulation of compressed air in the automatic supply/discharge path in a non-operation state,
The vehicle height adjustment device according to claim 2, wherein the control circuit controls the state transmission valve to an operating state when the main circuit is in an energized state. The air spring is a first air spring,
The supply/discharge path is a first supply/discharge path,
The supply/discharge control valve is a first supply/discharge control valve,
The pneumatic circuit includes a second supply/discharge path connecting the first supply/discharge path and a second air spring, and a second supply/discharge control valve disposed in the second supply/discharge path,
The automatic supply/discharge path is connected to both the first supply/discharge path and the second supply/discharge path,
The automatic supply/discharge control valve is positioned closer to the leveling valve than the connection portion of the first supply/discharge path and the second supply/discharge path with respect to the automatic supply/discharge path,
4. The second supply/discharge control valve according to claim 3, wherein the second supply/discharge control valve permits circulation of compressed air in the second supply/discharge path in an operating state and prohibits circulation of compressed air in the second supply/discharge path in a non-operating state. height adjustment device. The vehicle height adjustment device according to any one of claims 1 to 4, wherein the control circuit has an indicator that lights up when the main circuit is in an energized state.

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