Vehicle height adjustment method

Abstract

To enhance ride comfort by bringing a vehicle height change speed close to constant without depending on the weight of a vehicle body.SOLUTION: A vehicle height adjustment method comprises rotating a sub-spring via an actuator controlled by a computer and changing a vehicle height adjustment force applied to a lower arm, thus changing displacement of a main spring connected to the lower arm. A vehicle height is decreased to a riding vehicle height from a running vehicle height before occupants ride on the vehicle, and the vehicle height decreased due to riding is returned to the running vehicle height when all the occupants have finished riding. On the basis of an offset rotational angle, which is a rotational angle of the sub-spring when the vehicle height is returned to the riding vehicle height, a map showing a relation between the rotational angle of the sub-spring when the vehicle height is increased by rotating the sub-spring from the offset rotational angle and the vehicle height is selected. The actuator is controlled on the basis of the map, the sub-spring is rotated so that the vehicle height change speed is brought close to constant, and the vehicle height is increased to the running vehicle height from the riding vehicle height.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present disclosure relates to a vehicle height adjustment method. [Background technology]

[0002] As disclosed in Patent Document 1, the inventors developed a vehicle height adjustment device that changes the displacement of a main spring connected to a lower arm by rotating a secondary spring with an actuator to change the vehicle height adjustment force applied to the lower arm. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent application 2023-082389 Summary of the Invention [Problem to be solved by the invention]

[0004] In the vehicle height adjustment method using the vehicle height adjustment device, the vehicle height is lowered from the running vehicle height to the boarding vehicle height before the occupants board the vehicle, and the vehicle height is returned to the running vehicle height after all the occupants have boarded the vehicle. Here, the rotation angle θ of the auxiliary spring and the vehicle height have a nonlinear relationship. Furthermore, the nonlinear relationship between the rotation angle θ of the auxiliary spring and the vehicle height also changes depending on the weight of the vehicle body including the occupants.

[0005] Therefore, when returning the vehicle height to the driving height, if the auxiliary spring is rotated at a constant speed, the vehicle height change speed changes and the way in which the vehicle height change speed changes varies depending on the weight of the vehicle body, which could result in a deterioration in ride comfort.

[0006] The present disclosure has been made in consideration of the above circumstances, and provides a vehicle height adjustment method that brings the vehicle height change speed closer to a constant regardless of the weight of the vehicle body, thereby improving ride comfort. [Means for solving the problem]

[0007] A vehicle height adjustment method according to one aspect of the present disclosure includes: A vehicle height adjustment method for changing a displacement of a main spring connected to a lower arm by rotating a secondary spring using an actuator controlled by a computer and changing a vehicle height adjustment force applied to the lower arm, comprising: Before the passengers board the vehicle, the vehicle height is lowered from the driving height to the boarding height. When all passengers have boarded, the vehicle height that was lowered by the boarding is returned to the boarding vehicle height, a map indicating a relationship between the rotation angle of the auxiliary spring and the vehicle height when the vehicle height is raised by rotating the auxiliary spring from the offset rotation angle based on an offset rotation angle which is a rotation angle of the auxiliary spring when the vehicle height is returned to the riding height; The actuator is controlled based on the map to rotate the secondary spring so that the vehicle height change rate approaches a constant value, thereby raising the vehicle height from the boarding height to the traveling height.

[0008] In a vehicle height adjustment method according to one aspect of the present disclosure, the vehicle height is lowered from a driving height to a boarding height before passengers board the vehicle, and when all passengers have boarded, the vehicle height lowered by boarding is returned to the boarding height. Based on an offset rotation angle, which is the rotation angle of the secondary spring when the vehicle height is returned to the boarding height, a map is selected that shows the relationship between the rotation angle of the secondary spring and the vehicle height when the secondary spring is rotated from the offset rotation angle to raise the vehicle height. Then, the actuator is controlled based on the selected map to rotate the secondary spring so that the vehicle height change speed approaches a constant value, and the vehicle height is raised from the boarding height to the driving height. Here, since the offset rotation angle indicates the weight of the vehicle body, the vehicle height adjustment method according to this embodiment makes it possible to make the vehicle height change speed closer to a constant regardless of the weight of the vehicle body, thereby improving the ride comfort.

[0009] If the vehicle height falls below a predetermined threshold before all occupants have boarded, the vehicle height may be temporarily returned to the boarding vehicle height, and when all occupants have boarded, the vehicle height that was lowered due to boarding may be returned to the boarding vehicle height again. With this configuration, damage to the main spring can be suppressed.

[0010] One end of a first arm may be connected to the secondary spring so as to be rotatable around a rotation axis parallel to the rotation axis of the secondary spring, and one end of a second arm may be connected to the other end of the first arm so as to be rotatable around a rotation axis parallel to the rotation axis of the secondary spring, and the other end of the second arm may be connected to the lower arm. Effect of the Invention

[0011] The present disclosure makes it possible to provide a vehicle height adjustment method that makes it possible to keep the vehicle height change speed close to constant regardless of the weight of the vehicle body, thereby improving ride comfort. [Brief description of the drawings]

[0012] [Figure 1] 1 is a front view showing a configuration of a vehicle height adjusting mechanism used in a vehicle height adjusting method according to a first embodiment. [Diagram 2] 2 is a graph showing changes in the length H of the secondary spring S2 and the effective length Le1 of the first arm A1 depending on the rotation angle θ of the secondary spring S2 shown in FIG. [Diagram 3] 1 is a block diagram showing a configuration of a vehicle height adjusting system used in a vehicle height adjusting method according to a first embodiment. [Figure 4] 3 is a flowchart showing a vehicle height adjusting method according to the first embodiment. [Diagram 5] 11 is a graph of a map showing the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height. FIG. [Figure 6] 11 is a graph of a map showing the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, specific embodiments of the present disclosure will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, the following description and drawings are appropriately simplified for clarity of explanation.

[0014] (First embodiment) <Vehicle height adjustment mechanism configuration> First, the configuration of a vehicle height adjustment mechanism used in the vehicle height adjustment method according to the first embodiment will be described with reference to Fig. 1. Fig. 1 is a front view showing the configuration of a vehicle height adjustment mechanism used in the vehicle height adjustment method according to the first embodiment.

[0015] As shown in FIG. 1, the vehicle height adjusting mechanism used in the vehicle height adjusting method according to this embodiment includes a lower arm LA, a main spring S1, a shock absorber SA, a sub-spring S2, a first arm A1, a second arm A2, and an actuator 10.

[0016] One end of the lower arm LA is connected to the wheel WL via a knuckle (not shown), and the other end of the lower arm LA has a bush BS attached to the vehicle body (not shown). The lower arm LA is attached to the vehicle body so that the wheel WL can move up and down relative to the vehicle body.

[0017] The main spring S1 is disposed between the wheel WL and the vehicle body to support the vehicle body while absorbing shocks and vibrations from the road surface. In the example shown in Fig. 1, a coil spring is used as the main spring S1, but this is not limited thereto, and for example, an air spring may be used as the main spring S1.

[0018] As shown in Fig. 1, shock absorber SA is inserted into main spring S1 and damps the vertical vibration of the vehicle body caused by main spring S1. The upper ends of shock absorber SA and main spring S1 are attached to the vehicle body. The lower end of shock absorber SA is attached to lower arm LA. In other words, main spring S1 is connected to lower arm LA via shock absorber SA. Therefore, a downward main spring load F1 is generated at the attachment portion of shock absorber SA on lower arm LA.

[0019] As shown in Fig. 1, the base end side (the lower side in Fig. 1) of the secondary spring S2 is fixed to a spring holder SH, and generates a secondary spring load Fs2 from the base end side to the tip end side along the central axis of the secondary spring S2. The spring holder SH is fixed to a rotation axis AS of the actuator 10, and when the actuator 10 is driven to rotate the rotation axis AS, the secondary spring S2 fixed to the spring holder SH expands and contracts while rotating about the rotation axis AS of the actuator 10. Here, the central axis of the secondary spring is perpendicular to the rotation axis AS of the actuator 10, and when the secondary spring S2 is rotated by the actuator 10, the direction and magnitude of the secondary spring load Fs2 change.

[0020] 1, one end of the first arm A1 is rotatably connected to the tip side of the secondary spring S2, and the other end is rotatably connected to one end of the second arm A2. The rotation axis of the first arm A1 at the connection portion with the secondary spring S2 is parallel to the rotation axis AS of the secondary spring S2.

[0021] A first arm torque, which is the product (Fs2×Le1) of the secondary spring load Fs2 and the effective length Le1 of the first arm A1, is generated at the connection portion of the first arm A1 with the second arm A2. When the secondary spring S2 is rotated by the actuator 10, the effective length Le1 of the first arm A1 also changes.

[0022] 1, the second arm A2 has an L-shape, one end of which is rotatably connected to the other end of the first arm A1, and the other end of which is rotatably connected to the lower arm LA. The rotation axis of the second arm A2 at the connection with the first arm A1 is also parallel to the rotation axis AS of the secondary spring S2.

[0023] A second arm torque equal to the first arm torque (Fs2×Le1) is generated at the connection portion of the second arm A2 with the lower arm LA. The second arm torque is the product (F2×L2) of the second arm load F2 and the second arm length L2, and the second arm load F2 is a downward vehicle height adjustment force generated by the auxiliary spring load Fs2. In other words, it can be expressed as F2=(Fs2×Le1) / L2.

[0024] The actuator 10 is a drive source that rotates the main spring S1. The actuator 10 includes, for example, a motor and a reducer. The actuator 10 is controlled by a vehicle height control unit 20 shown in FIG.

[0025] 1, the height adjusting mechanism rotates the sub-spring S2 by the actuator 10 controlled by the height control unit 20 to change the height adjusting force F2 applied to the lower arm LA. As a result, the displacement of the main spring S1 connected to the lower arm LA changes, and the vehicle height also changes.

[0026] Next, the vehicle height adjustment will be described using equations with reference to FIG. The relationship shown in the following equation (1) is established between the vehicle height displacement X and the displacement X1 of the main spring S1 using the main spring arm ratio a1. X1 = a1 × X (1) Here, the main spring arm ratio a1 is the ratio (L4 / L3) of the length L4 from the bush BS of the lower arm LA to the mounting position of the main spring S1 in FIG. 1 to the length L3 of the lower arm LA, and is a constant.

[0027] The displacement X1 of the main spring S1 can be expressed by the following equation (2) using the mounting load F0 of the main spring S1, the main spring load F1 shown in FIG. 1, and the spring constant k1 of the main spring S1. X1 = (F0 - F1) / k1 (2)

[0028] The load F3 from the wheel WL shown in FIG. 1 satisfies the following equation (3) of balance between the main spring load F1, the second arm load (height adjustment force) F2, and the bush load F4, using the main spring arm ratio a1 and the arm ratio a2 of the second arm A2. F3 = a1 × F1 + a2 × F2 + F4 (3) Here, the arm ratio a2 of the second arm A2 is the ratio (L5 / L3) of the length L5 from the bush BS of the lower arm LA to the mounting position of the second arm A2 in FIG. 1 to the length L3 of the lower arm LA, and is a constant.

[0029] Further, the load F3 from the wheel WL is the difference between the sprung load Mg1 and the lower load Mg2, and F3=Mg1-Mg2 is established. Furthermore, the bush load F4 is the product of the bush constant kb and the vehicle height displacement X, and F4=kb×X holds.

[0030] Therefore, by modifying equation (3), the main spring load F1 can be expressed by the following equation (4). F1=(Mg1-Mg2-a2×F2-kb×X) / a1...(4) On the other hand, by substituting equation (2) into equation (1) and rearranging the main spring load F1, the main spring load F1 can be expressed by the following equation (5). F1 = F0 - a1 × k1 × X (5)

[0031] By substituting equation (5) into equation (4) and rearranging the equation for vehicle height displacement X, the vehicle height displacement X can be expressed by the following equation (6). X = (a1 × F0 - Mg1 + Mg2 + a2 × F2) / (a1 2 ×k1-kb) (6)

[0032] The only variables on the right side of equation (6) are the sprung load Mg1 and the second arm load (height adjustment force) F2. The sprung load Mg1 is the weight of the vehicle body including the passenger. As described above, the second arm load (height adjustment force) F2 can be expressed as F2=(Fs2×Le1) / L2 using the sub-spring load Fs2, the effective length Le1 of the first arm A1, and the second arm length L2.

[0033] As described above, the vehicle height displacement X varies depending on the sprung load Mg1, which is the weight of the vehicle body including the passenger, the auxiliary spring load Fs2, and the effective length Le1 of the first arm A1. As described above, the secondary spring load Fs2 and the effective length Le1 of the first arm A1 change with the rotation of the secondary spring S2. The secondary spring load Fs2 can be expressed as Fs2=k2×(H0−H) using the length H of the secondary spring S2, the natural length H0, and the spring constant k2. That is, the length H of the secondary spring S2 and the effective length Le1 of the first arm A1 change with the rotation of the secondary spring S2.

[0034] Here, Fig. 2 is a graph showing the change in length H of the secondary spring S2 and the effective length Le1 of the first arm A1 due to the rotation angle θ of the secondary spring S2 shown in Fig. 1. The horizontal axis of Fig. 2 shows the rotation angle θ (degrees) of the secondary spring S2, and the vertical axis of Fig. 2 shows the secondary spring length H (mm) and the effective length Le1 (mm) of the first arm A1. As shown in Fig. 1, the rotation angle θ is 0 degrees in the vertical upward direction, and the clockwise direction in Fig. 1 is the positive direction.

[0035] As shown in Fig. 2, the secondary spring length H and the effective length Le1 of the first arm A1 both have a nonlinear relationship with the rotation angle θ of the secondary spring S2. Here, Fig. 2 shows the change in the secondary spring length H and the effective length Le1 of the first arm A1 depending on the rotation angle θ of the secondary spring S2 at a given sprung load Mg1. When the sprung load Mg1 is different, the way in which the secondary spring length H and the effective length Le1 of the first arm A1 change depending on the rotation angle θ of the secondary spring S2 also differs.

[0036] Therefore, in the height adjustment mechanism shown in Figure 1, when the secondary spring S2 is rotated at a constant speed, the vehicle height change speed changes, and the way in which the vehicle height change speed changes varies depending on the weight of the vehicle body, which may result in a deterioration in ride comfort. It should be noted that the example shown in FIG. 2 is merely an example, and the change in the secondary spring length H and the effective length Le1 of the first arm A1 due to the rotation angle θ of the secondary spring S2 is not limited to the example shown in FIG.

[0037] <Vehicle height adjustment system configuration> Next, the configuration of a vehicle height adjustment system used in the vehicle height adjustment method according to the first embodiment will be described with reference to Fig. 3. Fig. 3 is a block diagram showing the configuration of a vehicle height adjustment system used in the vehicle height adjustment method according to the first embodiment.

[0038] As shown in Fig. 3, the vehicle height adjustment system used in the vehicle height adjustment method according to this embodiment includes an actuator 10, a vehicle height control unit 20, and a vehicle height sensor 30. In the vehicle height adjustment system shown in Fig. 3, the vehicle height control unit 20 acquires the vehicle height from the vehicle height sensor 30 and controls the actuator 10 to control the vehicle height.

[0039] More specifically, before a passenger boards the vehicle, for example based on instructions from a user, the vehicle height control unit 20 acquires the vehicle height from the vehicle height sensor 30 and controls the actuator 10 to lower the vehicle height from the driving height to the boarding height.

[0040] After all passengers have boarded, the vehicle height control unit 20, based on an instruction from the user, controls the actuator 10 while acquiring the vehicle height from the vehicle height sensor 30 to return the vehicle height lowered by boarding to the boarding height. Here, the rotation angle θ of the secondary spring S2 when the vehicle height is returned to the boarding height is defined as the offset rotation angle θo.

[0041] Furthermore, the vehicle height control unit 20 selects a map indicating the relationship between the rotation angle θ of the sub-spring S2 and the vehicle height when the vehicle height is raised by rotating the sub-spring S2 from the offset rotation angle θo based on the offset rotation angle θo. Here, the offset rotation angle θo is information indicating the weight of the vehicle body. That is, the vehicle height control unit 20 stores in advance a map indicating the relationship between the rotation angle θ of the sub-spring S2 corresponding to various assumed vehicle body weights and the vehicle height. The map will be described in detail later.

[0042] The vehicle height control unit 20 then controls the actuator 10 based on the selected map to rotate the secondary spring S2 so that the vehicle height change speed approaches a constant value, thereby raising the vehicle height from the boarding height to the driving height.

[0043] 3, the vehicle height control unit 20 includes a calculation unit such as a CPU (Central Processing Unit) and memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory) in which various programs and various data including the above-mentioned maps are stored. In other words, the vehicle height control unit 20 functions as a computer and controls the actuator 10 based on the above-mentioned various programs.

[0044] Therefore, the vehicle height control unit 20 shown in Fig. 3 can be configured as hardware using the above-mentioned CPU, memory, and other circuits. Also, the vehicle height control unit 20 can be realized as software using a program stored in a memory. In other words, the vehicle height control unit 20 can be realized in various forms using hardware, software, or a combination of both. In the example shown in FIG. 3, a memory (not shown) that stores the map is provided inside the vehicle height control unit 20, but it may be provided outside the vehicle height control unit 20.

[0045] The vehicle height sensor 30 is a sensor that detects the vehicle height. The vehicle height sensor 30 is attached to the vehicle, although not shown in Fig. 1. As shown in Fig. 3, the vehicle height sensor 30 outputs the detected vehicle height to the vehicle height control unit 20.

[0046] There is no limitation on the method of detecting the vehicle height by the vehicle height sensor 30. The vehicle height sensor 30 may indirectly detect the vehicle height by detecting the displacement between the vehicle body and the suspension. Alternatively, the vehicle height sensor 30 may directly detect the distance between the vehicle body and the road surface by using ultrasonic waves or a laser.

[0047] As described above, in the vehicle height adjustment system shown in Fig. 3, before passengers board the vehicle, the vehicle height is lowered from the driving vehicle height to the boarding vehicle height, and when all passengers have boarded, the vehicle height lowered by the boarding is returned to the boarding vehicle height. Based on the rotation angle θ (offset rotation angle θo) of the secondary spring S2 when the vehicle height is returned to the boarding vehicle height, a map is selected that indicates the relationship between the rotation angle θ of the secondary spring S2 and the vehicle height when the secondary spring S2 is rotated from the offset rotation angle θo to raise the vehicle height. Then, the actuator 10 is controlled based on the selected map to rotate the secondary spring S2 so that the vehicle height change speed approaches a constant value, and the vehicle height is raised from the boarding vehicle height to the driving vehicle height. Here, since the offset rotation angle θo indicates the weight of the vehicle body, in this height adjustment system, the vehicle height change speed can be made closer to a constant regardless of the weight of the vehicle body, improving the ride comfort.

[0048] <How to adjust the vehicle height> Next, a vehicle height adjustment method according to the first embodiment will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a flowchart showing the vehicle height adjustment method according to the first embodiment. Fig. 5 is a graph of a map showing the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height. Fig. 5 also shows steps ST1, ST2, and ST4 in Fig. 4. The vehicle height adjustment method according to this embodiment is executed by the vehicle height control unit 20 shown in Fig. 3, which is a computer. It should be noted that the example shown in FIG. 5 is merely one example, and the map showing the relationship between the rotation angle θ of the sub-spring S2 and the vehicle height is not limited to the example shown in FIG.

[0049] First, as shown in Fig. 4, before a passenger boards the vehicle, the vehicle height is lowered from the driving height to the boarding height (step ST1). Here, Fig. 5 shows a map MP1 for an empty vehicle before a passenger boards the vehicle. In step ST1, as shown in Fig. 5, the rotation angle θ of the spring S2 is changed according to the map MP1 from an angle corresponding to the driving height (about 30 degrees in the example of Fig. 5) to 0 degrees corresponding to the boarding height.

[0050] Next, as shown in Fig. 4, when all passengers have boarded, the vehicle height that was lowered by boarding is returned to the boarding vehicle height (step ST2). In step ST2, as shown in Fig. 5, the rotation angle θ of S2 is changed from 0 degrees to an angle corresponding to the boarding vehicle height (about 5 degrees in the example of Fig. 5). Here, the rotation angle θ of the secondary spring S2 when returned to the boarding vehicle height is defined as the offset rotation angle θo1.

[0051] Next, as shown in Fig. 4, a map showing the relationship between the rotation angle θ of the secondary spring S2 and the vehicle height when the secondary spring S2 is rotated from the offset rotation angle θo1 to raise the vehicle height is selected based on the offset rotation angle θo1 (step ST3). That is, in step ST3, the map MP2 shown in Fig. 5 is selected.

[0052] Finally, as shown in Fig. 4, the actuator 10 is controlled based on the selected map MP2 to rotate the secondary spring S2 so that the vehicle height change speed approaches a constant level, and the vehicle height is raised from the boarding vehicle height to the running vehicle height (step ST4). In step ST4, as shown in Fig. 5, the rotation angle θ of the spring S2 is changed according to the map MP2 from the offset rotation angle θo1 corresponding to the boarding vehicle height (about 5 degrees in the example of Fig. 5) to an angle corresponding to the running vehicle height (about 45 degrees in the example of Fig. 5). At this time, the actuator 10 is controlled to rotate the secondary spring S2 so that the vehicle height change speed approaches a constant level.

[0053] As described above, in the vehicle height adjustment method according to this embodiment, the vehicle height is lowered from the driving vehicle height to the boarding vehicle height before passengers board, and when all passengers have boarded, the vehicle height lowered by boarding is returned to the boarding vehicle height. Based on the rotation angle θ (offset rotation angle θo) of the secondary spring S2 when the vehicle height is returned to the boarding vehicle height, a map is selected that indicates the relationship between the rotation angle θ of the secondary spring S2 and the vehicle height when the secondary spring S2 is rotated from the offset rotation angle θo to raise the vehicle height. Then, the actuator 10 is controlled based on the selected map to rotate the secondary spring S2 so that the vehicle height change speed approaches a constant value, and the vehicle height is raised from the boarding vehicle height to the driving vehicle height. Here, since the offset rotation angle θo indicates the weight of the vehicle body, the vehicle height adjustment method according to this embodiment makes it possible to make the vehicle height change speed approach a constant regardless of the weight of the vehicle body, thereby improving the ride comfort.

[0054] Second embodiment Next, a vehicle height adjusting method according to a second embodiment will be described with reference to Fig. 6. Fig. 6 is a graph of a map showing the relationship between the rotation angle θ of the sub-spring S2 and the vehicle height. In the vehicle height adjusting method according to this embodiment, the flowchart is the same as the flowchart shown in Fig. 4. Step ST1 shown in FIG. 4 is similar to that of the first embodiment shown in FIG. 5, and therefore will not be described.

[0055] Next, in step ST2 shown in Fig. 4, in the example shown in Fig. 6, the vehicle height is temporarily returned to the boarding height because the vehicle height has dropped below a predetermined threshold before all passengers have boarded. Then, when all passengers have boarded, the vehicle height is returned to the boarding height again.

[0056] Therefore, the offset rotation angle θo2 (about 10 degrees in the example of FIG. 6), which is the rotation angle θ of the secondary spring S2 when returned to the riding height shown in FIG. 6, is larger than the offset rotation angle θo1 shown in FIG. If the vehicle height exceeds the threshold and continues to drop further, the secondary spring S2 cannot be rotated due to overload, and as a result, the vehicle height cannot be adjusted. Therefore, if the vehicle height drops below the threshold, the vehicle height is temporarily returned to the boarding height.

[0057] Next, in step ST3 shown in Fig. 4, a map showing the relationship between the rotation angle θ of the sub-spring S2 and the vehicle height when the vehicle height is raised by rotating the sub-spring S2 from the offset rotation angle θo2 is selected based on the offset rotation angle θo2. That is, the map MP3 shown in Fig. 6 is selected.

[0058] Finally, in step ST4 shown in Fig. 4, the rotation angle θ of the spring S2 is changed from the offset rotation angle θo2 (about 10 degrees in the example of Fig. 6) corresponding to the boarding height to an angle (about 60 degrees in the example of Fig. 6) corresponding to the running height in accordance with the map MP3 as shown in Fig. 6. At this time, the actuator 10 is controlled to rotate the sub-spring S2 so that the vehicle height change speed approaches a constant value.

[0059] Therefore, in the vehicle height adjustment method according to this embodiment, like the vehicle height adjustment method according to the first embodiment, the vehicle height change speed can be made closer to a constant regardless of the weight of the vehicle body, improving ride comfort. The other configurations are similar to those of the first embodiment, so detailed description will be omitted.

[0060] The present disclosure is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0061] 10 Actuator 20 Height control unit 30 Vehicle height sensor A1 First Arm A2 Second Arm AS Actuator Rotation Axis BS Bush LA Lower Arm S1 Main spring S2 Secondary spring SA Shock Absorber SH Spring Holder WL wheels

Claims

1. A vehicle height adjustment method for changing a displacement of a main spring connected to a lower arm by rotating a secondary spring using an actuator controlled by a computer and changing a vehicle height adjustment force applied to the lower arm, comprising: Before the passengers board the vehicle, the vehicle height is lowered from the driving height to the boarding height. When all passengers have boarded, the vehicle height that was lowered by the boarding is returned to the boarding vehicle height, a map indicating a relationship between the rotation angle of the auxiliary spring and the vehicle height when the vehicle height is raised by rotating the auxiliary spring from the offset rotation angle based on an offset rotation angle which is a rotation angle of the auxiliary spring when the vehicle height is returned to the riding height; controlling the actuator based on the map, rotating the auxiliary spring so that a vehicle height change speed approaches a constant value, and raising the vehicle height from the boarding vehicle height to the traveling vehicle height; How to adjust the vehicle height.

2. If the vehicle height falls below a predetermined threshold before all passengers have boarded, the vehicle height is temporarily returned to the boarding height; When all passengers have boarded, the vehicle height lowered by boarding is returned to the boarding vehicle height. The vehicle height adjusting method according to claim 1 .

3. One end of a first arm is connected to the secondary spring so as to be rotatable around a rotation axis parallel to a rotation axis of the secondary spring, One end of a second arm is connected to the other end of the first arm so as to be rotatable around a rotation axis parallel to the rotation axis of the secondary spring, The other end of the second arm is connected to the lower arm. A vehicle height adjusting method according to claim 1 or 2.

Images