How to adjust vehicle height

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] This disclosure relates to a vehicle height adjustment method.

Background Art

[0002] As shown in Patent Document 1, the inventors have developed a vehicle height adjustment device that changes the displacement of a main spring connected to a lower arm by changing the vehicle height adjustment force applied to the lower arm by rotating a sub-spring by an actuator.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the vehicle height adjustment method using the above vehicle height adjustment device, before the passengers board, the vehicle height is lowered from the driving vehicle height to the boarding vehicle height, and after all the passengers have boarded, the vehicle height is returned to the driving vehicle height. Here, the rotation angle θ of the sub-spring and the vehicle height have a non-linear relationship. Furthermore, the non-linear relationship between the rotation angle θ of the sub-spring and the vehicle height also changes depending on the weight of the vehicle body including the passengers.

[0005] Therefore, when returning the vehicle height to the driving vehicle height, if the sub-spring is rotated at a constant speed, the vehicle height change speed changes, and the way the vehicle height change speed changes differs depending on the weight of the vehicle body, which may deteriorate the riding comfort.

[0006] This disclosure has been made in view of such circumstances, and provides a vehicle height adjustment method that makes the vehicle height change speed approach a constant regardless of the weight of the vehicle body and improves the riding comfort.

Means for Solving the Problems

[0007] A vehicle height adjustment method relating to one aspect of this disclosure is: A method for adjusting vehicle height, which involves rotating a secondary spring using a computer-controlled actuator and changing the vehicle height adjustment force applied to the lower arm, thereby changing the displacement of the main spring connected to the lower arm, Before the occupants board, the vehicle height is lowered from the driving height to the boarding height. Once all occupants have boarded, the vehicle height, which has been lowered by boarding, is returned to the boarding height. Based on the offset rotation angle, which is the rotation angle of the auxiliary spring when the vehicle height is returned to the aforementioned passenger height, a map is selected that shows the 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 the aforementioned map, the actuator is controlled to rotate the auxiliary spring so that the vehicle height change rate approaches a constant, thereby raising the vehicle height from the passenger vehicle height to the driving vehicle height.

[0008] In a vehicle height adjustment method according to one aspect of this disclosure, the vehicle height is lowered from the driving height to the boarding height before the occupants board, and after all occupants have boarded, the vehicle height that was lowered by boarding is returned to the boarding height. Based on the offset rotation angle, which is the rotation angle of the auxiliary 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 auxiliary spring and the vehicle height when the vehicle height is raised by rotating the auxiliary spring from the offset rotation angle. Then, the actuator is controlled based on the selected map to rotate the auxiliary spring so that the vehicle height change rate approaches a constant, 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 allows the vehicle height change speed to be kept close to constant regardless of the weight of the vehicle body, thereby improving ride comfort.

[0009] If the vehicle height drops below a predetermined threshold before all occupants have boarded, the vehicle height may be temporarily returned to the boarding height, and once all occupants have boarded, the vehicle height that has been lowered by boarding may be returned again to the boarding height. This configuration helps to suppress damage to the main spring.

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

[0011] This disclosure provides a vehicle height adjustment method that improves ride comfort by bringing the vehicle height change speed closer to a constant regardless of the vehicle's weight. [Brief explanation of the drawing]

[0012] [Figure 1] This 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. [Figure 2] Figure 1 is a graph showing the change in the length H of the auxiliary spring S2 and the effective length Le1 of the first arm A1 as the rotation angle θ of the auxiliary spring S2. [Figure 3] This 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. [Figure 4] This is a flowchart showing a vehicle height adjustment method according to the first embodiment. [Figure 5] This graph shows a map illustrating the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height. [Figure 6] This graph shows a map illustrating the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height. [Modes for carrying out the invention]

[0013] The specific embodiments described herein will be described in detail below with reference to the drawings. However, this disclosure is not limited to the embodiments described below. Also, for clarity, the following descriptions and drawings have been simplified as appropriate.

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

[0015] As shown in FIG. 1, the vehicle height adjustment mechanism used in the vehicle height adjustment method according to the present 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 a wheel WL via a knuckle (not shown), and a bush BS at the other end is attached to a vehicle body (not shown). The lower arm LA is attached to the vehicle body so that the wheel WL can move up and down with respect to the vehicle body.

[0017] The main spring S1 is disposed between the wheel WL and the vehicle body, and while supporting the vehicle body, it mitigates impacts and vibrations from the road surface. In the example shown in FIG. 1, a coil spring is used as the main spring S1, but it is not limited thereto, and for example, an air spring or the like may be used as the main spring S1.

[0018] As shown in FIG. 1, the shock absorber SA is inserted into the main spring S1 and attenuates the up-and-down vibration of the vehicle body caused by the main spring S1. The upper end portions of the shock absorber SA and the main spring S1 are attached to the vehicle body. The lower end portion of the shock absorber SA is attached to the lower arm LA. That is, the main spring S1 is connected to the lower arm LA via the shock absorber SA. Therefore, a downward main spring load F1 is generated at the attachment portion of the shock absorber SA on the lower arm LA.

[0019] As shown in Figure 1, the auxiliary spring S2 has its base end (lower side in Figure 1) fixed to the spring holder SH, and generates an auxiliary spring load Fs2 that extends from the base end to the tip end along the central axis of the auxiliary spring S2. The spring holder SH is fixed to the rotation axis AS of the actuator 10, and when the actuator 10 is driven to rotate the rotation axis AS, the auxiliary spring S2 fixed to the spring holder SH rotates around the rotation axis AS of the actuator 10 and undergoes expansion and contraction motion. Here, the central axis of the auxiliary spring is perpendicular to the rotation axis AS of the actuator 10, and when the auxiliary spring S2 is rotated by the actuator 10, the direction and magnitude of the auxiliary spring load Fs2 change.

[0020] As shown in Figure 1, one end of the first arm A1 is rotatably connected to the tip of the auxiliary spring S2, and the other end is rotatably rolled to one end of the second arm A2. The axis of rotation of the first arm A1 at the connection point with the auxiliary spring S2 is parallel to the axis of rotation AS of the auxiliary spring S2.

[0021] At the connection point between the first arm A1 and the second arm A2, a first arm torque is generated, which is the product of the auxiliary spring load Fs2 and the effective length Le1 of the first arm A1 (Fs2 × Le1). When the auxiliary spring S2 is rotated by the actuator 10, the effective length Le1 of the first arm A1 also changes.

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

[0023] At the connection point between the second arm A2 and the lower arm LA, a second arm torque equal to the first arm torque (Fs2 × Le1) is generated. The second arm torque is the product of the second arm load F2 and the second arm length L2 (F2 × L2), and the second arm load F2 is the downward ride height adjustment force generated by the auxiliary spring load Fs2. That is, 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 reduction gear. The actuator 10 is controlled by the vehicle height control unit 20 shown in Figure 2, as will be described later.

[0025] As explained above, in the vehicle height adjustment mechanism shown in Figure 1, the actuator 10 controlled by the vehicle height control unit 20 rotates the auxiliary spring S2, thereby changing the vehicle height adjustment 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, we will explain vehicle height adjustment using mathematical formulas, referring to Figure 1. The following relationship (1) holds 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 Figure 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 Figure 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 Figure 1 is in equilibrium with the main spring load F1, the second arm load (vehicle 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, as shown in equation (3). 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 Figure 1 to the length L3 of the lower arm LA, and is a constant.

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

[0030] Therefore, by rearranging 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, substituting equation (2) into equation (1) and rearranging for 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] Substituting equation (5) into equation (4) and rearranging for vehicle height displacement X, we can express vehicle height displacement X as follows: equation (6). X = (a1 × F0 - Mg1 + Mg2 + a2 × F2) / (a1 2 ×k1-kb) ...(6)

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

[0033] As explained above, the vehicle height displacement X is affected by the sprung load Mg1, which is the weight of the vehicle body including the occupants, the auxiliary spring load Fs2, and the effective length Le1 of the first arm A1. As described above, the auxiliary spring load Fs2 and the effective length Le1 of the first arm A1 change with the rotation of the auxiliary spring S2. The auxiliary spring load Fs2 can be expressed as Fs2 = k2 × (H0 - H), where H is the length of the auxiliary spring S2, H0 is its natural length, and k2 is its spring constant. In other words, the length H of the auxiliary spring S2 and the effective length Le1 of the first arm A1 change with the rotation of the auxiliary spring S2.

[0034] Here, Figure 2 is a graph showing the change in the length H of the auxiliary spring S2 and the effective length Le1 of the first arm A1 as the rotation angle θ of the auxiliary spring S2 shown in Figure 1. The horizontal axis of Figure 2 represents the rotation angle θ (degrees) of the auxiliary spring S2, and the vertical axis of Figure 2 represents the auxiliary spring length H (mm) and the effective length Le1 (mm) of the first arm A1. As shown in Figure 1, the rotation angle θ is defined as 0 degrees when vertically upward, and clockwise rotation in Figure 1 is considered the positive direction.

[0035] As shown in Figure 2, the auxiliary spring length H and the effective length Le1 of the first arm A1 are both in a nonlinear relationship with the rotation angle θ of the auxiliary spring S2. Here, Figure 2 shows the change in the auxiliary spring length H and the effective length Le1 of the first arm A1 with respect to the rotation angle θ of the auxiliary spring S2 at a predetermined sprung load Mg1. If the sprung load Mg1 is different, the way in which the auxiliary spring length H and the effective length Le1 of the first arm A1 change with respect to the rotation angle θ of the auxiliary spring S2 will also be different.

[0036] Therefore, in the ride height adjustment mechanism shown in Figure 1, when the auxiliary spring S2 is rotated at a constant speed, the rate of change in ride height changes, and the way in which the rate of change in ride height changes differs depending on the weight of the vehicle, which may worsen the ride comfort. Note that the example shown in Figure 2 is merely one example, and the changes in the sub-spring length H and the effective length Le1 of the first arm A1 due to the rotation angle θ of the sub-spring S2 are not limited in any way to the example shown in Figure 2.

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

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

[0039] More specifically, before the occupants board, for example based on instructions from the 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] Furthermore, once all occupants have boarded, the vehicle height control unit 20, for example based on instructions from the user, acquires the vehicle height from the vehicle height sensor 30 and controls the actuator 10 to return the vehicle height, which has been lowered by boarding, to the boarding height. Here, the rotation angle θ of the auxiliary spring S2 when it 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 showing the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height when the vehicle height is raised by rotating the auxiliary spring S2 from the offset rotation angle θo. Here, the offset rotation angle θo is information indicating the weight of the vehicle body. In other words, the vehicle height control unit 20 has pre-stored maps showing the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height corresponding to various assumed vehicle body weights. Details of the maps will be described later.

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

[0043] Although not shown in Figure 3, the vehicle height control unit 20 includes, for example, a processing unit such as a CPU (Central Processing Unit), and memory such as RAM (Random Access Memory) and ROM (Read Only Memory) that store various programs and various data including the map mentioned above. In other words, the vehicle height control unit 20 functions as a computer and controls the actuator 10 based on the various programs mentioned above.

[0044] Therefore, the vehicle height control unit 20 shown in Figure 3 can be composed of the CPU, memory, and other circuits as hardware. Furthermore, the vehicle height control unit 20 can be implemented as software, such as by a program stored in memory. In other words, the vehicle height control unit 20 can be implemented in various forms using hardware, software, or a combination of both. In the example shown in Figure 3, the memory (not shown) for storing the map is located inside the vehicle height control unit 20, but it may also be located outside the vehicle height control unit 20.

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

[0046] The method for detecting vehicle height using the vehicle height sensor 30 is not limited in any way. The vehicle height sensor 30 may indirectly detect 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 using ultrasound or a laser.

[0047] As explained above, in the vehicle height adjustment system shown in Figure 3, the vehicle height is lowered from the driving height to the boarding height before the occupants board, and once all occupants have boarded, the vehicle height that was lowered by boarding is returned to the boarding height. Based on the rotation angle θ (offset rotation angle θo) of the auxiliary spring S2 when it is returned to the boarding height, a map is selected that shows the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height when the vehicle height is raised by rotating the auxiliary spring S2 from the offset rotation angle θo. Then, based on the selected map, the actuator 10 is controlled to rotate the auxiliary spring S2 so that the vehicle height change speed approaches a constant, and the vehicle height is raised from the boarding height to the driving height. Here, since the offset rotation angle θo represents the weight of the vehicle, this ride height adjustment system allows the speed of ride height change to be kept close to constant regardless of the weight of the vehicle, thereby improving ride comfort.

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

[0049] First, as shown in Figure 4, the vehicle height is lowered from the driving height to the boarding height before the occupants board (step ST1). Here, Figure 5 shows map MP1 in the empty vehicle before the occupants board. In step ST1, as shown in Figure 5, the rotation angle θ of the spring S2 is changed along map MP1 from an angle corresponding to the driving height (approximately 30 degrees in the example in Figure 5) to 0 degrees corresponding to the boarding height.

[0050] Next, as shown in Figure 4, once all occupants have boarded, the vehicle height, which has been lowered by boarding, is returned to the boarding height (step ST2). In step ST2, as shown in Figure 5, the rotation angle θ of S2 is changed from 0 degrees to an angle corresponding to the boarding height (approximately 5 degrees in the example in Figure 5). Here, the rotation angle θ of the auxiliary spring S2 when returned to the boarding height is defined as the offset rotation angle θo1.

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

[0052] Finally, as shown in Figure 4, the actuator 10 is controlled based on the selected map MP2 to rotate the auxiliary spring S2 so that the vehicle height change rate approaches a constant, raising the vehicle height from the passenger height to the driving height (step ST4). In step ST4, as shown in Figure 5, the rotation angle θ of the spring S2 is changed along the map MP2 from an offset rotation angle θo1 corresponding to the passenger height (approximately 5 degrees in the example in Figure 5) to an angle corresponding to the driving height (approximately 45 degrees in the example in Figure 5). At this time, the actuator 10 is controlled to rotate the auxiliary spring S2 so that the vehicle height change rate approaches a constant.

[0053] As described above, in the vehicle height adjustment method according to this embodiment, before occupants board the vehicle, the vehicle height is lowered from the driving vehicle height to the boarding vehicle height, and once all occupants have boarded, the vehicle height that was lowered by boarding is returned to the boarding vehicle height. Based on the rotation angle θ (offset rotation angle θo) of the auxiliary spring S2 when it is returned to the boarding vehicle height, a map is selected that shows the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height when the vehicle height is raised by rotating the auxiliary spring S2 from the offset rotation angle θo. Then, based on the selected map, the actuator 10 is controlled to rotate the auxiliary spring S2 so that the vehicle height change speed approaches a constant, and the vehicle height is raised from the boarding vehicle height to the driving vehicle height. Here, since the offset rotation angle θo represents the weight of the vehicle body, the vehicle height adjustment method according to this embodiment allows the vehicle height change speed to be kept close to constant regardless of the weight of the vehicle body, thereby improving ride comfort.

[0054] (Second embodiment) Next, with reference to Figure 6, a vehicle height adjustment method according to the second embodiment will be described. Figure 6 is a graph showing the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height. In the vehicle height adjustment method according to this embodiment, the flowchart is the same as the flowchart shown in Figure 4. Step ST1 shown in Figure 4 is the same as that of the first embodiment shown in Figure 5, so its explanation is omitted.

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

[0056] Therefore, the offset rotation angle θo2 (approximately 10 degrees in the example in Figure 6), which is the rotation angle θ of the auxiliary spring S2 when the vehicle is returned to the riding height shown in Figure 6, is larger than the offset rotation angle θo1 shown in Figure 5. If the vehicle height continues to drop below a threshold, the auxiliary spring S2 will become unable to rotate due to overload, and as a result, vehicle height adjustment will become impossible. Therefore, if the vehicle height drops below a threshold, the vehicle height will be temporarily returned to the passenger height.

[0057] Next, in step ST3 shown in Figure 4, based on the offset rotation angle θo2, a map is selected that shows the relationship between the rotation angle θ of the auxiliary spring S2 and the vehicle height when the auxiliary spring S2 is rotated from the offset rotation angle θo2 to raise the vehicle height. That is, map MP3 shown in Figure 6 is selected.

[0058] Finally, in step ST4 shown in Figure 4, as shown in Figure 6, the rotation angle θ of the spring S2 is changed along the map MP3 from an offset rotation angle θo2 corresponding to the passenger ride height (approximately 10 degrees in the example in Figure 6) to an angle corresponding to the driving ride height (approximately 60 degrees in the example in Figure 6). At this time, the actuator 10 is controlled to rotate the auxiliary spring S2 so that the speed of ride height change approaches a constant.

[0059] Therefore, in the vehicle height adjustment method according to this embodiment, similar to the vehicle height adjustment method according to the first embodiment, the vehicle height change speed can be made to be close to constant regardless of the weight of the vehicle body, thereby improving ride comfort. The other components are the same as in the first embodiment, so a detailed explanation will be omitted.

[0060] This disclosure is not limited to the embodiments described above, and may be modified as appropriate without departing from its intent. [Explanation of Symbols]

[0061] 10 Actuators 20 Vehicle Height Control Unit 30 Vehicle height sensor A1 First Arm A2 Second Arm Rotation axis of AS actuator BS Bush LA Lower Arm S1 Main spring S2 auxiliary spring SA Shock Absorber SH spring holder WL wheels

Claims

1. A method for adjusting vehicle height, which involves rotating a secondary spring using a computer-controlled actuator and changing the vehicle height adjustment force applied to the lower arm, thereby changing the displacement of the main spring connected to the lower arm, Before the occupants board, the vehicle height is lowered from the driving height to the boarding height. Once all occupants have boarded, the vehicle height, which has been lowered by boarding, is returned to the boarding height. Based on the offset rotation angle, which is the rotation angle of the auxiliary spring when the vehicle height is returned to the aforementioned passenger height, a map is selected that shows the 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 the map, the actuator is controlled to rotate the auxiliary spring so that the vehicle height change speed approaches a constant, thereby raising the vehicle height from the passenger vehicle height to the driving vehicle height. How to adjust the ride height.

2. If the vehicle height falls below a predetermined threshold before all occupants have boarded, the vehicle height will be temporarily returned to the boarding vehicle height. Once all occupants have boarded, the vehicle height, which has been lowered by boarding, is returned to the boarding height. The method for adjusting the vehicle height according to claim 1.

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

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