JP2020179786A - Vehicle height adjusting device - Google Patents

Abstract

To provide a vehicle height adjusting device capable of automatically switching between permission and rejection of vehicle height adjustment performed manually by a switch operation.SOLUTION: A vehicle height adjusting device comprises: an air pressure circuit 50 which performs supply/discharge of compressed air to/from first and second air springs 56 and 66; and a control circuit 30 which controls supply of power to plural electromagnetic valves respectively constituting the air pressure circuit 50. The control circuit 30 comprises: a main circuit 33 on which a main switch 21 is arranged; a lifting circuit 36 on which a lifting switch 22 is arranged, and which is conductive when the main circuit 33 is in a conduction state; and an ECU 25 which individually controls power supply to the main circuit 33 and the lifting circuit 36. The ECU 25 controls the main circuit 33 to a conductive state when vehicle speed is lower than permission speed, but controls the main circuit 33 to a non-conductive state when vehicle speed is equal to prohibition speed or higher, and further, when vehicle speed is equal to the permission speed or higher but lower than the prohibition speed, the ECU maintains the main circuit 33 in a state immediately before the vehicle speed transits to that range.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle height adjusting device.

For example, as in Patent Document 1, a vehicle such as a tractor to which a trailer or the like is connected is provided with a vehicle height adjusting device capable of adjusting the vehicle height. An example of the vehicle height adjusting device adjusts the vehicle height by controlling the supply and discharge of compressed air to a pair of left and right air springs. Such a vehicle height adjusting device is configured to be able to manually adjust the vehicle height by operating a switch when connected to the trailer, and is configured to be able to automatically adjust the vehicle height when traveling.

Japanese Unexamined Patent Publication No. 07-215186

In the above-mentioned vehicle height adjustment device, one of the purposes of improving convenience and safety is to allow manual vehicle height adjustment by operating a switch when the vehicle is moving when connected to a trailer, and to switch when traveling. It is required to prohibit manual vehicle height adjustment by operation.

An object of the present invention is to provide a vehicle height adjusting device capable of automatically switching the permission or disapproval of manual vehicle height adjustment by operating a switch.

The vehicle height adjusting device that solves the above problems is a vehicle height adjusting device that adjusts the vehicle height of the vehicle, and includes a pneumatic circuit having a plurality of solenoid valves and supplying and discharging compressed air to an air spring. A control circuit for controlling the supply of electric power to each of a plurality of solenoid valves is provided, and the control circuit can be energized when a main switch that can be operated by a driver is provided and the main switch is in the ON state. A configured main circuit, an elevating circuit configured to be energized when the main circuit is energized by disposing an elevating switch that can be operated by a driver, and power supply to the main circuit and the elevating circuit. When the main switch is in the ON state, the electric power control unit acquires the vehicle speed of the vehicle, and when the vehicle speed is less than the permitted speed, the main circuit is used. When the vehicle speed is controlled to be energized and the vehicle speed is greater than or equal to the prohibited speed, the main circuit is controlled to be de-energized, and when the vehicle speed is in the speed range equal to or more than the permitted speed and less than the prohibited speed. The main circuit is maintained in a 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 between enabling and disallowing the manual vehicle height adjustment by operating the switch, that is, enabling / disabling the up / down switch.

In the vehicle height adjusting device, the pneumatic circuit includes an air supply path connected to an air supply source, an air supply / exhaust valve arranged in the air supply path, the air supply / exhaust valve, and the air spring. The air supply / discharge valve is provided with a supply / discharge passage for connecting the air supply / discharge passage and a supply / discharge control valve arranged in the supply / discharge passage, and the air supply / discharge valve communicates the supply / discharge passage with the air supply passage in an operating state and is not. It is a solenoid valve that communicates the supply / discharge path to the outside in the operating state, and the supply / discharge control valve permits the flow of compressed air in the supply / discharge path in the operating state and compresses in the supply / discharge path in the non-operating state. It is a solenoid valve that prohibits the flow of air, and the control circuit is configured so that the air supply / exhaust valve and the supply / exhaust control valve can be controlled in an operating state by an ascending operation of the elevating switch, and the elevating switch is lowered. It is preferable that the air supply / discharge valve is controlled to the non-operating state by operation and the supply / discharge control valve can be controlled to the operating state.

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

In the vehicle height adjusting device, the pneumatic circuit includes a leveling valve that controls supply and discharge of compressed air to the air spring so that the vehicle height is maintained at a predetermined vehicle height, the air spring, and the vehicle height adjusting device. An automatic supply / discharge path that connects the leveling valve, an automatic supply / discharge control valve that is an air operating valve arranged in the automatic supply / discharge path, and an automatic supply path that connects the leveling valve and the air supply path. The state transmission valve is provided with an operating pressure supply path that is branched from the automatic supply path and can supply an operating pressure to the automatic supply / discharge control valve, and a state transmission valve arranged in the operating pressure supply path. Is an electromagnetic valve that permits the flow of compressed air in the working pressure supply path in the operating state and supplies the working pressure to the automatic supply / discharge control valve, and the automatic supply / discharge control valve is the automatic supply / discharge control valve in the operating state. The flow of compressed air in the exhaust passage is prohibited and the flow of compressed air in the automatic supply / exhaust passage is permitted in the non-operating state, and the control circuit operates the state transmission valve when the main circuit is energized. It is preferable to control the state.

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

In the vehicle height adjusting device, the air spring is the first air spring, the supply / discharge path is the first supply / discharge path, the supply / discharge control valve is the first supply / discharge control valve, and the pneumatic circuit. Is provided with a second supply / discharge path connecting the first supply / discharge path and the second air spring, and a second supply / discharge control valve arranged in the second supply / discharge path, and the automatic supply / discharge is provided. The road is connected to both the first supply / discharge path and the second supply / discharge path, and the automatic supply / discharge control valve is the first supply / discharge path and the second supply / discharge to the automatic supply / discharge path. Located on the leveling valve side of the connecting portion of the road, the second supply / discharge control valve permits the flow of compressed air in the second supply / discharge path in the operating state and the second supply / discharge in the non-operating state. The circulation of compressed air on the road should be prohibited.

According to the above configuration, since the first air spring and the second air spring communicate with each other through the automatic supply / discharge path, the compressed air can flow between the first air spring and the second air spring. As a result, the amount of compressed air of the first air spring and the amount of compressed air of the second air spring can be adjusted in a well-balanced manner according to the load at each time.

In the vehicle height adjusting device, it is preferable that the control circuit has an indicator that lights up when the main circuit is energized.
According to the above configuration, even if the main switch is in the ON state, the driver can be notified of the enable / disable of the up / down switch with an indicator. As a result, the driver can confirm whether the up / down switch is valid or invalid by the indicator.

It is a figure which shows the schematic structure of the vehicle which carries one Embodiment of the vehicle height adjustment device, (a) figure which shows the state which the trailer and a tractor are connected, (b) before the trailer and a tractor are connected. The figure which shows the state of. The figure which shows the schematic structure of one Embodiment of a vehicle height adjustment device. The block diagram which shows the structure around the ECU. (A) A diagram showing an example of the state of the first relay during acceleration, and (b) a diagram showing an example of the state of the first relay during deceleration. The figure which shows the state of the vehicle height adjustment device when the vehicle height is automatically raised to the set vehicle height. The figure which shows 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 the vehicle height adjustment device when the vehicle height is raised by the ascending operation. The figure which shows the state of the vehicle height adjustment device when the vehicle height is lowered by the descent operation.

An embodiment of the vehicle height adjusting device will be described with reference to FIGS. 1 to 8. First, with reference to FIG. 1, a schematic configuration of a vehicle equipped with an embodiment of a vehicle height adjusting device will be described.
As shown in FIGS. 1A and 1B, an example of the vehicle 10 is a tractor to which a trailer 11 or the like is connected. The vehicle 10 has a vehicle body 13 having a coupler (not shown) connecting 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 the 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) arranged between the vehicle body 13 and the rear axle 18. It has a vehicle height adjusting device 20 that adjusts the vehicle height. The vehicle height adjusting device 20 is configured to automatically adjust the vehicle height to a predetermined vehicle height during traveling, and to adjust the vehicle height by operating a switch by a driver when the vehicle is connected to the trailer 11. As a switch that can be operated by the driver, the vehicle height adjusting device 20 has a main switch 21 and an elevating switch 22. These various switches 21 and 22 are installed in 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 capable of raising the vehicle height by a driver's ascending operation when the main switch 21 is in the ON state, and is a switch capable of lowering the vehicle height by a driver's descending operation. is there.

Further, the vehicle height adjusting device 20 has an ECU (Electronic Control Unit) 25 that permits / prohibits the adjustment of the vehicle height by operating the elevating 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 unit. The ECU 25 is mainly composed of an MCU (Micro Control Unit) 26 (see FIG. 3) in which a processor, a memory, an input interface, an output interface, and the like are connected to each other via a bus. A vehicle speed sensor 27 that detects the 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 the input interface, and disables the main switch 21 when the acquired vehicle speed v does not satisfy the permission condition. The term "invalidation of the main switch 21" as used herein means that even if the main switch 21 is in the on state, it is considered to be in the off state, and the adjustment of the vehicle height by operating the elevating switch 22 is prohibited. Hereinafter, the state in which the main switch 21 is disabled is referred to as an invalid state.

The vehicle height adjusting device 20 will be described in more detail with reference to FIGS. 2 to 8.
As shown in FIG. 2, the vehicle height adjusting device 20 includes the control circuit 30 and the 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 in which the various switches 21 and 22 and the ECU 25 described above are incorporated. The control circuit 30 controls the supply of electric power to various solenoid valves constituting the pneumatic circuit 50 according to the vehicle speed v, the state of the main switch 21, and the state of the elevating 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. In FIGS. 2, 3 and 5 to 8, the thick solid line indicates the wiring portion constituting the control circuit 30, and the thin solid line indicates the piping portion constituting the pneumatic circuit 50.

(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 the battery 31 mounted on the vehicle 10. The control circuit 30 has a main circuit 33 connected to the 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 in the ON state. That is, the main circuit 33 is in the energized state when both the main switch 21 and the first relay circuit 28 are in the on state, and is in the non-energized state when one of the main switch 21 and the first relay circuit 28 is in the off state. It becomes.

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

The control circuit 30 has an elevating circuit 36 that connects the ECU 25 and the elevating switch 22 and is connected to the power supply circuit 32 via the second relay circuit 29 built in the ECU 25. The elevating circuit 36 is an electric circuit connected to the 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. The state transmission circuit 38 is an electric circuit connected to the 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. Further, 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 lifting circuit 36 while the lifting switch 22 is being lifted. The control circuit 30 has a second circuit 42 that connects the elevating circuit 36 with a frame by a route different from that of the first circuit 41 while the elevating switch 22 is being lowered. The second circuit 42 is electrically connected to the first circuit 41 at the confluence 43 in the first circuit 41.

The control circuit 30 has a connection circuit 44. The connection circuit 44 electrically connects the first electrical connection point 46 located on the elevating switch 22 side of the confluence point 43 in the first circuit 41 and the second electrical connection point 47 in the second circuit 42. A diode 48 is arranged in the connection circuit 44. The diode 48 permits energization from the first electrical connection point 46 to the second electrical connection point 47, while prohibits energization from the second electrical connection point 47 to the first electrical connection point 46.

The 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 controls the first relay circuit 28 to be turned on when the vehicle speed v is within the permitted range A of less than the permitted speed v1 (for example, 5 km / h). To do. When the vehicle speed v is in the prohibited range C equal to or higher than the prohibited speed v2 (for example, 20 km / h), the MCU 26 disables the main switch 21 by controlling the first relay circuit 28 to the off state. When the vehicle speed v reaches the maintenance range B having the permitted speed v1 or more and less than the prohibited speed v2, the MCU 26 maintains the state of the first relay circuit 28 in the state immediately before that. Specifically, when the vehicle speed v reaches the maintenance range B by acceleration, in other words, when the vehicle speed v is in the maintenance range B shifted from the permission range A, the MCU 26 turns on the first relay circuit 28. maintain. On the contrary, when the vehicle speed v reaches the maintenance range B by deceleration, in other words, when the vehicle speed v is in the maintenance range B shifted from the prohibition 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 in the permission range A and when the vehicle speed v is in the maintenance range B shifted from the permission range A. In other words, the MCU 26 determines that the permission condition is not satisfied when the vehicle speed v is in the prohibition range C and when the vehicle speed v is in the maintenance range B shifted from the prohibition range C.

The 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 energized is input to the MCU 26. The MCU 26 controls the second relay circuit 29 to be in the ON state when the permission condition is satisfied and the main switch 21 is in the ON state (the main circuit 33 is in the energized state). The MCU 26 turns off the second relay circuit 29 when the main switch 21 is in the off state (the main circuit 33 is in the non-energized state) even if the permission condition is satisfied, in addition to the case where the permission condition is not satisfied. Control. When the second relay circuit 29 is in the ON state, the vehicle height adjusting device 20 is in the manual mode in which the vehicle height is adjusted by operating the elevating switch 22. When the second relay circuit 29 is in the off state, the vehicle height adjusting 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 or the like (not shown). The pneumatic circuit 50 has an air supply path 53 that connects the air supply source 51 and the air supply / exhaust 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 that connects the air supply / discharge valve 52 and the first air spring 56. A first supply / discharge control valve 58 is provided in the first supply / discharge passage 57.

The air supply / exhaust valve 52 is a pilot-type solenoid valve that uses compressed air supplied from the air supply path 53 to the pilot flow path 60 branched at the pilot branch point 59. The air supply / discharge valve 52 is controlled to operate when the first circuit 41 is energized. The air supply / exhaust valve 52 in the operating state communicates the air supply path 53 with the first supply / exhaust path 57. The non-operating air supply / exhaust valve 52 closes the air supply path 53 and communicates the first supply / exhaust path 57 with the air discharge path 61. The compressed air that has flowed into the air discharge path 61 is discharged to the outside from the silencer 62.

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

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

The second supply / discharge control valve 68 is an air-operated valve that can switch between an operating state and a non-operating state in synchronization with the first supply / discharge control valve 58. The second supply / exhaust control valve 68 operates when the operating pressure is supplied through the pilot flow path 60 when the first supply / exhaust control valve 58 is in the operating state and the first supply / exhaust control valve 58 is in the non-operating state. The 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 allows the second air spring 66 and the air supply / discharge valve 52 in the non-operating state. Prohibit the flow of compressed air between and.

The pneumatic circuit 50 with respect 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 each of the valves 52, 58, 68 described above is in the inactive state. It has a leveling valve 70 that controls the supply and discharge of compressed air. In the leveling valve 70, for example, a lever (not shown) is connected to the rear axle 18 via a link rod, and the lever is mechanically operated by a change in the relative position of the vehicle body 13 with respect to the rear axle 18. Controls the supply and discharge of compressed air.

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

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

The pneumatic circuit 50 has a branch path 77 that branches from the branch point 76 of the automatic supply path 71. The branch path 77 is configured so that the compressed air in the air supply path 53 can be supplied to the automatic supply / discharge control valve 73 as a working fluid. The pneumatic circuit 50 has a state transmission valve 78 in the branch path 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 the operating state when the state transmission circuit 38 is in the energized state, and is controlled to the non-operating state when the state transmission circuit 38 is in the 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 permitting the flow of compressed air in the branch path 77. The state transmission valve 78 in the non-operating state cuts off the supply of the operating pressure to the automatic supply / exhaust control valve 73 and connects the branch path 77 to the air discharge path 61 described above.

The operation of the vehicle height adjusting device 20 described above will be described with reference to FIGS. 5 to 8. In FIGS. 5 to 8, the thick dotted line indicates the wiring portion in the non-energized state, and the thin dotted line indicates the piping portion through which the compressed air does not flow.

(auto mode)
As shown in FIGS. 5 and 6, in the automatic mode, the vehicle height adjusting device 20 automatically adjusts the vehicle height to the set vehicle height. In addition, in FIG. 5 and FIG. 6, the main switch 21 is shown in the off state.

In the automatic mode, the first relay circuit 28 and the second relay circuit 29 are controlled to the off state. 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 an inactive state. Further, since the first circuit 41 and the second circuit 42 are in the 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 in the non-operating state. .. That is, in the automatic mode, the supply and discharge of compressed air to the first air spring 56 and the second air spring 66 is performed through the automatic supply / discharge path 72.

As shown in FIG. 5, when the vehicle height rises to the set vehicle height, the compressed air of the air supply source 51 is the air supply path 53, the diversion point 69, the automatic supply path 71, the leveling valve 70, and the automatic supply / discharge. It is supplied to the first air spring 56 and the second air spring 66 through the road 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 to the 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 adjusting device 20 adjusts the vehicle height according to the operation of the lifting switch 22 by the driver. In the manual mode, since the main switch 21 and the first relay circuit 28 are in the ON state, the indicator 35 is in the lit state. Further, since the second relay circuit 29 is controlled to be in the ON state, the state transmission circuit 38 is in the energized state. 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 / discharge of compressed air to the first air spring 56 and the second air spring 66 through the automatic supply / discharge path 72 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 operate. At this time, the compressed air of the air supply source 51 is supplied to the first air spring 56 through the air supply path 53 and the first supply / exhaust path 57. Further, the compressed air of the air supply source 51 is supplied to the second air spring 66 through the air supply path 53, the first supply / exhaust path 57, and the second supply / exhaust path 67. In this way, the vehicle height adjusting 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 of the first circuit 41, the connection circuit 44, and the second circuit 42 is energized. As a result, the air supply / exhaust valve 52 is controlled to the non-operating state, and the first supply / exhaust control valve 58 and the second supply / exhaust control valve 68 are controlled to the operating state. At this time, the compressed air of the first air spring 56 is discharged to the outside through the first supply / discharge passage 57, the air supply / discharge valve 52, and the air discharge passage 61. Further, the compressed air of the second air spring 66 is discharged to the outside through the second supply / discharge passage 67, the first supply / discharge passage 57, the air supply / discharge valve 52, and the air discharge passage 61. In this way, the vehicle height adjusting device 20 lowers the vehicle height by discharging compressed air from the first air spring 56 and the second air spring 66.

The effect of this embodiment will be described.
(1) In the vehicle height adjusting device 20, even if the main switch 21 is in the ON state, the state of the main circuit 33 is switched according to the vehicle speed v. Therefore, even if the main switch 21 is kept in the ON state, it is possible to automatically switch whether or not to manually adjust the vehicle height according to the vehicle speed v.

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

(3) In the vehicle height adjusting device 20, the ECU 25 is configured to acquire the vehicle speed v but does not require coordinated control with other ECUs. Therefore, since it is not necessary to confirm the cooperation between the ECU 25 and the other ECU 25 at the design stage, the time required for confirming the cooperation between the ECUs can be omitted. That is, by using one ECU 25 alone, it is possible to simplify the configuration of the vehicle height adjusting device 20 and shorten the time required for the design stage of the vehicle height adjusting device 20.

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

(5) The first supply / discharge path 57 and the second supply / discharge path 67 are connected by an 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 a well-balanced manner according to the load at that time.

(6) In the vehicle height adjusting device 20, the vehicle height can be automatically adjusted to the set vehicle height when the main circuit 33 is in the off state.
(7) The vehicle height adjusting device 20 has an indicator 35 that lights up when the main circuit 33 is energized. Therefore, the driver can determine whether the vehicle height adjustment by the elevating switch 22 is valid or invalid by turning on / off the indicator.

This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
-Even if the vehicle height adjusting device 20 has, in addition to the indicator 35, or instead of the indicator 35, a notification device that notifies the driver of the validity / invalidity of the vehicle height adjustment by the lift switch 22 by, for example, voice. Good.

When the vehicle height adjusting device 20 has a plurality of air springs, the vehicle height adjusting device 20 may have a pneumatic circuit that separately supplies and discharges compressed air to each of the plurality of air springs.
-The vehicle height adjusting device 20 may have a configuration in which the set vehicle height is set by adjusting the vehicle height with the elevating 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. It is preferable that the output port has a configuration in which the supply of electric power is controlled based on, for example, the vehicle speed of the vehicle or the operating state of the engine. With such a configuration, the versatility of the ECU 25 can be expanded.

10 ... Vehicle, 11 ... Trailer, 13 ... Vehicle 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 ... Lift switch, 25 ... ECU, 26 ... MCU, 27 ... Vehicle speed sensor, 28 ... 1st relay circuit, 29 ... 2nd relay circuit, 30 ... Control circuit, 31 ... Battery, 32 ... Power circuit, 33 ... main circuit, 34 ... notification circuit, 35 ... indicator, 36 ... elevating 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 / exhaust valve, 53 ... Air supply path, 54 ... Check valve, 56 ... 1st air spring, 57 ... 1st supply / exhaust path, 58 ... 1st supply / exhaust control valve, 59 ... Pilot branch point, 60 ... Pilot flow path, 61 ... Air discharge Road, 62 ... Silencer, 65 ... Branch confluence, 66 ... Second air spring, 67 ... Second supply / discharge path, 68 ... Second supply / discharge control valve, 69 ... Divergence point, 70 ... Leveling valve, 71 ... Automatic supply Road, 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 path, 78 ... State transmission valve ..

Claims (5)

It is a vehicle height adjustment device that adjusts the vehicle height of the vehicle.
A pneumatic circuit that has multiple solenoid valves to supply and discharge compressed air to the air spring,
A control circuit for controlling the supply of electric power to each of the plurality of solenoid valves is provided.
The control circuit is provided with a main circuit in which a driver-operable main switch is provided and is configured to be energized when the main switch is in the ON state, and an elevating switch in which the driver can be operated. It is provided with an elevating circuit configured to be energized when the main circuit is energized, and a power control unit that separately controls the power supply to the main circuit and the elevating 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 permitted speed, controls the main circuit to be energized, and the vehicle speed is higher than the permitted speed. When the speed is greater than or equal to the prohibited speed, the main circuit is controlled to be in a non-energized state, and when the vehicle speed is in the speed range equal to or more than the permitted speed and less than the prohibited speed, the vehicle speed is changed to the state immediately before the vehicle speed shifts to the speed range. A vehicle height adjusting device that maintains the main circuit. The pneumatic circuit includes an air supply path connected to an air supply source, an air supply / exhaust valve arranged in the air supply path, and a supply / exhaust path connecting the air supply / exhaust valve and the air spring. , A supply / discharge control valve provided in the supply / discharge path,
The air supply / discharge valve is a solenoid valve that communicates the supply / discharge path to the air supply path in an operating state and communicates the supply / discharge path to the outside in a non-operating state.
The supply / discharge control valve is a solenoid valve that permits the flow of compressed air in the supply / discharge path in the operating state and prohibits the flow of compressed air in the supply / discharge path in the non-operating state.
The control circuit is configured so that the air supply / discharge valve and the supply / discharge control valve can be controlled to be in an operating state by an ascending operation of the elevating switch, and the air supply / exhaust valve is in an inactive state by a descending operation of the elevating switch. The vehicle height adjusting device according to claim 1, which is configured to be able to control the supply / discharge control valve to an operating state. The pneumatic circuit automatically connects a leveling valve that controls the supply and discharge of compressed air to the air spring so that the vehicle height is maintained at a predetermined vehicle height, and the air spring and the leveling valve. A supply / discharge passage, an automatic supply / discharge control valve which is an air operating valve arranged in the automatic supply / discharge passage, an automatic supply passage connecting the leveling valve and the air supply passage, and a branch from the automatic supply passage. A working pressure supply path capable of supplying working pressure to the automatic supply / discharge control valve and a state transmission valve arranged in the working pressure supply path are provided.
The state transmission valve is a solenoid valve that permits the flow of compressed air in the working pressure supply path in the operating state and supplies the working pressure to the automatic supply / discharge control valve.
The automatic supply / discharge control valve prohibits the flow of compressed air in the automatic supply / discharge path in the operating state and permits the flow of compressed air in the automatic supply / discharge path in the non-operating state.
The vehicle height adjusting device according to claim 2, wherein the control circuit controls the state transmission valve to an operating state when the main circuit is energized. The air spring is the first air spring,
The supply / discharge route is the first supply / discharge route.
The supply / discharge control valve is the first supply / discharge control valve.
The pneumatic circuit includes a second supply / discharge path connecting the first supply / discharge path and the second air spring, and a second supply / discharge control valve arranged 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 located on the leveling valve side of the connection portion of the first supply / discharge path and the second supply / discharge path with respect to the automatic supply / discharge path.
The second supply / discharge control valve according to claim 3, which permits the flow of compressed air in the second supply / discharge passage in the operating state and prohibits the flow of compressed air in the second supply / discharge passage in the non-operating state. Vehicle height adjustment device. The vehicle height adjusting 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 energized.