Vehicle height adjustment device

1. A vehicle height adjustment device comprising:

a changer configured to change a relative position of a body of a vehicle to an axle of a wheel of the vehicle;

a detector configured to detect the relative position; and

a controller configured to control the changer to change the relative position based on a detection value detected by the detector so as to control a height of the body as a vehicle height, wherein

the changer includes;

a storage chamber configured to store a fluid,

a pump having a cylinder and configured to suction the fluid stored in the storage chamber into the cylinder and to discharge the fluid from the cylinder,

an accommodation chamber that accommodates the fluid, and

a passage switch unit having a first communication passage, a second communication passage and a third communication passage,

the first communication passage communicates between the pump and the storage chamber,

the second communication passage communicates between the pump and the accommodation chamber,

the third communication passage communicate between the storage chamber and the accommodation chamber,

the passage switch unit is capable of switching among the first, second, and third communication passages based on a current supplied to the passage switch unit, and

the controller is configured to control the changer to maintain the vehicle height when there is a possibility of a malfunction in the detector.

2. The vehicle height adjustment device according to claim 1 ,

wherein the controller is configured to detect the malfunction during which the detection value detected by the detector is kept in a vicinity of an upper limit value.

3. The vehicle height adjustment device according to claim 1 ,

wherein the controller is configured to detect the malfunction in the detector based on the detection value detected by the detector and based on a target value of the relative position.

4. The vehicle height adjustment device according to claim 3 ,

wherein the controller is configured to determine that there is the possibility of the malfunction in the detector when the detection value detected by the detector is equal to or larger than the target value of the relative position for a predetermined period of time.

5. The vehicle height adjustment device according to claim 4 ,

wherein, even after the controller determines that there is the possibility of the malfunction in the detector, the controller is configured to control the changer to stop maintaining the vehicle height and to return to normal control when the detection value detected by the detector is less than the target value of the relative position.

6. The vehicle height adjustment device according to claim 4 ,

wherein the controller is configured to confirm that the malfunction has occurred in the detector when the detection value detected by the detector is equal to or larger than the target value of the relative position for a predetermined reference period of time.

7. The vehicle height adjustment device according to claim 2 ,

wherein the controller is configured to detect the malfunction in the detector based on the detection value detected by the detector and based on a target value of the relative position.

8. The vehicle height adjustment device according to claim 7 ,

wherein the controller is configured to determine that there is the possibility of the malfunction in the detector when the detection value detected by the detector is equal to or larger than the target value of the relative position for a predetermined period of time.

9. The vehicle height adjustment device according to claim 8 ,

wherein, even after the controller determines that there is the possibility of the malfunction in the detector, the controller is configured to control the changer to stop maintaining the vehicle height and to return to normal control when the detection value detected by the detector is less than the target value of the relative position.

10. The vehicle height adjustment device according to claim 8 ,

wherein the controller is configured to confirm that the malfunction has occurred in the detector when the detection value detected by the detector is equal to or larger than the target value of the relative position for a predetermined reference period of time.

11. The vehicle height adjustment device according to claim 1 ,

wherein the changer comprises

a spring comprising one end supported at a side of the body and another end supported at a side of the wheel, and

an adjustor comprising an accommodation chamber to accommodate a fluid and configured to adjust a length of the spring in accordance with an amount of the fluid in the accommodation chamber, wherein

the pump suctions the fluid stored in the storage chamber into the cylinder when a relative distance between the body and the wheel increases, and discharges the fluid from the cylinder when the relative distance between the body and the wheel decreases, and

the passage switch unit is configured to switch states among a state of guiding the fluid discharged from the pump into the accommodation chamber to increase the amount of the fluid in the accommodation chamber, a state of guiding the fluid in the accommodation chamber into the storage chamber to decrease the amount of the fluid in the accommodation chamber, and a state of maintaining the amount of the fluid in the accommodation chamber, and

the controller is configured to control the changer to maintain the state of maintaining the amount of the fluid in the accommodation chamber when there is the possibility of the malfunction in the detector.

12. The vehicle height adjustment device according to claim 1 , wherein the controller controls the changer to maintain the vehicle height by causing the current supplied to the passage switch unit to go to zero.

13. The vehicle height adjustment device according to claim 1 , wherein the passage switch unit closes the third communication passage so that the fluid discharged from the pump reaches the reservoir chamber through the first communication passage.

14. The vehicle height adjustment device according to claim 1 , wherein the passage switch unit closes the first and third communication passages so that the fluid discharged from the pump reaches the accommodation chamber through the second communication passage.

15. The vehicle height adjustment device according to claim 1 , wherein the passage switch unit closes the first communication passage so that the fluid discharged from the accommodation chamber reaches the reservoir chamber through the third communication passage.