Vehicle suspension system

Abstract

The rebound stroke amount on the inner wheel and the bump stroke amount on the outer wheel during cornering can be easily made asymmetrical, according to the characteristics of each vehicle type. [Solution] The vehicle suspension system comprises a suspension device that supports the left and right wheels, and a stabilizer bar that connects the two suspension devices via a stabilizer link. It further comprises a stabilizer slide mechanism that slides the stabilizer bar, and a control unit that controls the drive of the drive unit of the stabilizer slide mechanism. The control unit slides the stabilizer bar via the stabilizer slide mechanism when the vehicle is turning, thereby displacing the roll axis.

Description

Technical Field

[0001] The present invention relates to a suspension device for a vehicle.

Background Art

[0002] A vehicle equipped with an independent suspension type suspension device is provided with a stabilizer device. The stabilizer device has a stabilizer bar. The stabilizer bar functions as a torsion spring.

[0003] As disclosed in, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2023-134849), both ends of this stabilizer bar are connected via a stabilizer link to stabilizer brackets provided on the struts of the left and right suspension devices.

[0004] When the vehicle is turning, if there is a difference in the stroke amounts of the left and right suspension devices, a torsional stress is generated in the stabilizer bar. Then, a restoring force (reaction force) that attempts to return this twist acts on the suspension device, and the stroke amounts of the left and right suspension devices are corrected in a direction to become the same. As a result, the inclination (rolling) of the vehicle body toward the outer wheel side during turning is suppressed, and the stability of the vehicle body during turning is improved.

[0005] By the way, the difference in the stroke amounts generated in the left and right suspension devices during turning is the difference between the bump amount (compression) on the outer wheel side of the turn and the rebound amount (extension) on the inner wheel side of the turn. Generally, this bump amount and rebound amount are substantially symmetric. Therefore, the center (roll axis) of the rolling generated in the vehicle body does not change due to the twist of the stabilizer bar, and the roll axis is at the center in the vehicle width direction of the vehicle body. However, depending on the vehicle type, it may be possible to ensure the running stability by making the bump stroke amount on the outer wheel side of the turn and the rebound stroke amount on the inner wheel side of the turn asymmetric during running.

[0006] For example, displacing the roll axis from the center in the vehicle width direction towards the center of rotation (towards the inner wheel side) reduces the rebound amount on the inner wheel side and relatively increases the bump amount on the outer wheel side. This results in high responsiveness.

[0007] Conversely, shifting the roll axis from the center of the vehicle's width towards the outer turning wheel side increases the rebound amount on the inner turning wheel side and relatively reduces the bump stroke amount on the outer turning wheel side. This causes the steering to become slightly understeer, allowing the driver to sense that the vehicle is exceeding its speed limit.

[0008] By the way, some suspension systems, such as the one disclosed in Patent Document 1, incorporate rebound springs and helper springs. Rebound springs restrict the extension of the shock absorber with a repulsive force.

[0009] This rebound spring does not restrict the compression of the shock absorber. On the other hand, a helper spring is attached above or below the main spring to ensure the extension stroke of the main spring.

[0010] By reducing the stroke of the rebound spring or increasing the stroke of the helper spring, the stroke amounts of the left and right suspension systems become asymmetrical during cornering. As a result, it becomes possible to displace the roll axis from the center in the vehicle width direction to one side. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2023-134849 [Overview of the project] [Problems that the invention aims to solve]

[0012] However, rebound springs and helper springs are devices added to the suspension system. Adding these devices to an existing suspension system is subject to size constraints. Furthermore, rebound springs and helper springs need to maintain their original function. In particular, when both wheels bounce (stroke) simultaneously, the rebound spring's reaction force is applied to the main spring, which can easily affect ride comfort.

[0013] Therefore, there are limitations to adding devices such as rebound springs or helper springs to existing suspension systems to displace the roll axis away from the center in the vehicle width direction.

[0014] The present invention aims to provide a vehicle suspension system that can easily make the rebound stroke amount on the inner wheel side and the bump stroke amount on the outer wheel side asymmetrical during driving, according to the characteristics of each vehicle type. [Means for solving the problem]

[0015] The present invention relates to a vehicle suspension system comprising a suspension system that supports left and right wheels, and a stabilizer bar that connects the two suspension systems via a stabilizer link, wherein the suspension system further comprises a stabilizer slide mechanism that slides the stabilizer bar, and a control unit that controls the drive of the drive unit of the stabilizer slide mechanism, and the control unit slides the stabilizer bar via the stabilizer slide mechanism to displace the roll axis when the vehicle is turning. [Effects of the Invention]

[0016] According to the present invention, the control unit drives the stabilizer slide mechanism to slide the stabilizer bar and displace the roll axis, so that the rebound stroke amount on the inner wheel side and the bump stroke amount on the outer wheel side during driving can be easily made asymmetrical according to the characteristics of each vehicle model. [Brief explanation of the drawing]

[0017] [Figure 1] Front view showing the schematic configuration of the suspension device [Figure 2] Cross-sectional view of the main part of the stabilizer link mechanism [Figure 3] Schematic configuration diagram of the control unit [Figure 4] Plan view showing the stabilizer device when the auto mode switch is OFF [Figure 5] Plan view showing the stabilizer device in a state where the roll axis is displaced from the center in the vehicle width direction to the inner turning wheel side [Figure 6] Plan view showing the stabilizer device in a state where the roll axis is displaced from the center in the vehicle width direction to the outer turning wheel side [Figure 7] Front view showing the vehicle body roll during turning when the auto mode switch is OFF [Figure 8] Front view showing the vehicle body roll in a state where the roll axis is displaced from the center in the vehicle width direction to the inner turning wheel side [Figure 9] Front view showing the vehicle body roll in a state where the roll axis is displaced from the center in the vehicle width direction to the outer turning wheel side [[ID=3))

Embodiments for Carrying Out the Invention

[0018] Hereinafter, an embodiment of the present invention will be described based on the drawings. In FIG. 1, a suspension device 1 of a vehicle M (see FIGS. 7 to 9) is shown. This suspension device 1 can be arranged not only on the left and right front wheels (steering wheels) but also on the left and right rear wheels. Hereinafter, the case where it is arranged on the left and right front wheels (steering wheels) 1l, 1r will be exemplified and described.

[0019] This suspension device 1 includes a suspension device 2 and a stabilizer device 3. The suspension device 2 includes a steering knuckle 2a. The steering knuckle 2a rotatably supports an axle to which the left and right wheels 1l, 1r are fixedly attached. Further, the suspension device 2 has a suspension main body (not shown). This suspension main body is, for example, a strut-type suspension. The strut portion of this suspension main body is fixedly attached to the steering knuckle 2a.

[0020] The lower portion of the steering knuckle 2a is connected to the outside in the vehicle width direction of the lower arm 4 via a ball joint 5. The inside in the vehicle width direction of this lower arm 4 is connected to the vehicle body side via a rubber bush 6.

[0021] The stabilizer device 3 has a straight bar-shaped stabilizer bar 3a having a torsional spring property. This stabilizer bar 3a is disposed in parallel with a steering gear box provided in a steering mechanism portion (not shown). Arm portions 3b are bent and formed at both ends of this stabilizer bar 3a.

[0022] One end of a stabilizer link 7 is connected to this arm portion 3b via a ball joint 8. The other end of this stabilizer link 7 is connected to the strut portion of the suspension main body via a connecting portion 9 such as a ball joint or a bush.

[0023] Further, as shown in FIG. 4, in a state where the center in the vehicle width direction of the stabilizer bar 3a (hereinafter referred to as "the center of the stabilizer bar 3a") is at the center in the vehicle width direction (Y / O) of the vehicle M, that is, in the neutral position, a pair of stabilizer (abbreviated as "stabi") slide mechanism portions 12 are arranged at a predetermined interval at symmetrical positions on the left and right sandwiching the center (Y / O) of this stabilizer bar 3a. The stabi slide mechanism portion 12 supports the stabilizer bar 3a in a state of restricting rotation in the axial circumferential direction.

[0024] As shown in Figure 2, the stabilizer slide mechanism 12 has a stabilizer support cylinder 13, an inner cylinder 14, and an outer cylinder 15. The stabilizer support cylinder 13 has an inner cylinder 13a and a hard bush 13b. The outer circumference of the hard bush 13b is fixed to the inner circumference of the inner cylinder 13a. This hard bush 13b is a cylindrical body. The inner circumference of this hard bush 13b is fixed to the outer circumference of the stabilizer bar 3a. In addition, a male threaded portion (trapezoidal thread) 13c is formed on the outer circumference of the inner cylinder 13a.

[0025] A female threaded portion (trapezoidal thread) 14a is formed on the inner circumference of the central cylinder portion 14, which screws into the male threaded portion 13c. In addition, an outer engaging portion 14b is formed in an annular shape on the outer circumference of the central cylinder portion 14.

[0026] The outer cylinder portion 15 is fixed to the vehicle body on its outer circumference. An inner engaging portion 15a is formed in an annular shape on the inner circumference of this outer cylinder portion 15. This inner engaging portion 15a is engaged with the outer engaging portion 14b. The middle cylinder portion 14 is allowed to rotate on its axis, while its axial sliding is restricted by the engagement of the outer engaging portion 14b with the inner engaging portion 15a.

[0027] Furthermore, each stabilizer slide mechanism 12 has its own stabilizer drive motor 16. Each stabilizer drive motor 16 is, for example, a stepping motor. A drive gear 16a is axially mounted on the motor shaft of each stabilizer drive motor 16. This drive gear 16a meshes with a driven gear portion (not shown) formed on the outer circumference of the central cylinder portion 14. The rotation of this drive gear 16a slides the stabilizer bar 3a left and right in the vehicle width direction.

[0028] The rotation of each stabilizer drive motor 16 is controlled by the control unit 21 shown in Figure 3. This control unit 21 is composed of a microcontroller. The microcontroller includes a CPU, RAM, ROM, rewritable non-volatile memory (flash memory or EEPROM), and peripheral devices. The RAM of the microcontroller is provided as the CPU's work area, where various data from the CPU is temporarily stored. The ROM stores programs and fixed data necessary for the CPU to execute various processes. The CPU is also called an MPU (Microprocessor) or processor. Alternatively, a GPU (Graphics Processing Unit) or GSP (Graph Streaming Processor) may be used instead of a CPU. Alternatively, a selective combination of CPU, GPU, and GSP may be used.

[0029] The auto mode switch 22 and parameter detection unit 23 are connected to the input side of this control unit 21. The stabilizer motor drive unit 25 is connected to the output side of the control unit 21. The control unit 21 also has a stabilizer lever ratio calculation unit 21a as a control unit. The stabilizer lever ratio calculation unit 21a calculates the lever ratio λ for sliding the stabilizer bar 3a toward the left and right wheels 1l and 1r.

[0030] As shown in Figures 4 and 5, the lever ratio λ is the ratio of the distance Y1 (arm distance) from the contact point of the wheel 1r (1l) (in this embodiment, conveniently set to the center T / O of the tire width) to the connecting portion 9 of the stabilizer link 7 on the suspension device 2 side (stabilizer distance) Yr (or Yl) to the support point of the stabilizer slide mechanism 12 (in this embodiment, conveniently set to the axial center of the stabilizer support cylinder 13) (λ = Y1 / Yr, or λ = Y1 / Yl). This arm distance Y1 is almost fixed. Therefore, the lever ratio λ is a function of the stabilizer distance Yr or Yl.

[0031] Furthermore, as shown in Figures 4 and 5, the distance Y0 when the roll axis G is in the neutral position is the stabilizer distance (neutral distance) from the contact point (T / O) of the wheels 1r and 1l to the support point of the stabilizer slide mechanism 12 when the center (Y / O) of the stabilizer bar 3a coincides with the center in the width direction of the vehicle M (YO=Yl=Yr).

[0032] Furthermore, the auto mode switch 22 is a switch operated by the driver. The parameter detection unit 23 is a general term for sensors that detect parameters necessary when the stabilizer lever ratio calculation unit 21a calculates the lever ratio λ. Parameters detected by the parameter detection unit 23 include steering angle, steering angular velocity, yaw rate, vehicle speed, longitudinal acceleration, deceleration, lateral acceleration, number of occupants, occupant seating position, vehicle height at the front and rear of the vehicle, and tire pressure. For example, the change in the tilt of the vehicle body during cornering is estimated based on the number of occupants and occupant seating position. Also, the vehicle load weight is estimated based on the vehicle height at the front and rear of the vehicle and tire pressure. These parameters may be factors that affect the change in the stroke amount of the left and right suspension devices 2 when the vehicle M is cornering.

[0033] When the driver turns on the auto mode switch 22, the stabilizer lever ratio calculation unit 21a is activated. Based on the parameters detected by the parameter detection unit 23, the stabilizer lever ratio calculation unit 21a determines the optimal lever ratio λ according to the driving state of the vehicle M during turning. In this embodiment, the stabilizer lever ratio calculation unit 21a determines the lever ratio λ on the driver's side wheel (right wheel 1r in the case of a right-hand drive vehicle). Alternatively, the stabilizer lever ratio calculation unit 21a may determine the lever ratio λ on the turning inner wheel side (right wheel 1r in the case of a right turn).

[0034] The stabilizer bar 3a is slid in the vehicle width direction by the stabilizer slide mechanism 12. The stabilizer lever ratio calculation unit 21a determines the lever ratio λ for one wheel 1r (1l). This uniquely determines the lever ratio for the other wheel 1l (1r). The stabilizer lever ratio calculation unit 21a may also determine the lever ratio λ for the passenger-side wheel, or the lever ratio for the outer turning wheel.

[0035] The stabilizer lever ratio calculation unit 21a outputs a drive signal corresponding to the calculated lever ratio λ to the stabilizer motor drive unit 25. The stabilizer motor drive unit 25 synchronously rotates the pair of stabilizer drive motors 16 by a predetermined angle according to the drive signal from the stabilizer lever ratio calculation unit 21a.

[0036] The drive gear 16a of the stabilizer drive motor 16 is meshed with a driven gear portion (not shown) formed on the outer circumference of the central cylinder portion 14 provided in the stabilizer slide mechanism portion 12.

[0037] The operation of the stabilizer slide mechanism 12 will now be described. When the stabilizer drive motor 16 rotates, the inner cylinder portion 14 rotates via the driven gear portion. The outer engaging portion 14b formed on the outer circumference of the inner cylinder portion 14 is slidably fitted into the inner engaging portion 15a formed on the inner circumference of the outer cylinder portion 15. The outer circumference of this outer cylinder portion 15 is fixed to the vehicle body. Therefore, the movement of the inner cylinder portion 14 in the axial direction is restricted, and only rotation in the direction of the axis is permitted.

[0038] The female threaded portion 14a formed on the inner circumference of the central cylinder portion 14 is screwed onto the male threaded portion 13c formed on the outer circumference of the inner cylinder portion 13a of the stabilizer support cylinder portion 13. When the central cylinder portion 14 rotates, the female threaded portion 14a pushes the stabilizer support cylinder portion 13 axially via the male threaded portion 13c.

[0039] The inner cylinder portion 13a and the hard bush 13b of the stabilizer support cylinder portion 13 are fixed together. Furthermore, the hard bush 13b is fixed to the stabilizer bar 3a. Therefore, when the stabilizer support cylinder portion 13 is fed out in the axial direction, the stabilizer bar 3a slides integrally in the same direction.

[0040] Figure 4 shows a state where the center of the stabilizer bar 3a coincides with the center Y / O in the vehicle width direction of the vehicle M. The roll axis G of the vehicle M is set at the center of the stabilizer bar 3a. Also, the stabilizer bar 3a tilts together with the vehicle M. Therefore, as shown in Figure 7, when the center of the stabilizer bar 3a coincides with the center Y / O in the vehicle width direction of the vehicle M, the roll axis G is on the center (Y / O) in the vehicle width direction.

[0041] Furthermore, as shown in Figure 5, when the stabilizer bar 3a slides in the direction of the right wheel 1r, the center of the stabilizer bar 3a moves by Y / O' from the center Y / O in the vehicle width direction to the direction of the right wheel 1r. As a result, as shown in Figure 8, the roll axis G is displaced by Y / O' from the center Y / O in the vehicle width direction to the direction of the right wheel 1r.

[0042] Furthermore, as shown in Figure 6, when the stabilizer bar 3a slides in the direction of the left wheel 1l, the center of the stabilizer bar 3a moves by Y / O' from the center Y / O in the vehicle width direction to the left wheel 1l direction. As a result, as shown in Figure 9, the roll axis G is displaced by Y / O' from the center Y / O in the vehicle width direction to the left wheel 1l direction.

[0043] Next, the operation of this embodiment with this configuration will be explained. Figures 4 and 7 show the initial state when the auto mode switch 22 is OFF. In the initial state when the auto mode switch 22 is OFF, the lever ratio λ is set to its initial value (λ = Y1 / Y0). In this state, the center of the stabilizer bar 3a coincides with the center (Y / O) in the vehicle width direction of the vehicle M.

[0044] When the driver switches the auto mode switch 22 from ON to OFF, the stabilizer lever ratio calculation unit 21a outputs a drive signal with the initial lever ratio λ (=Y1 / Y0) to the stabilizer motor drive unit 25, returning the center of the stabilizer bar 3a to the center in the vehicle width direction (Y / O). In this case, the roll axis G is on the center in the vehicle width direction (Y / O) (see Figure 7).

[0045] When the vehicle M is driven with the driver's auto mode switch ON, the stabilizer lever ratio calculation unit 21a checks whether the vehicle speed detected by the parameter detection unit 23 is equal to or greater than a preset vehicle speed (for example, 60 km / h). This preset vehicle speed is the value used to determine whether or not to start lever ratio control. Therefore, if the vehicle speed of vehicle M is less than or equal to the speed at which this determination is made, the lever ratio λ is fixed to its initial value.

[0046] The stabilizer lever ratio calculation unit 21a determines that the vehicle speed of vehicle M exceeds the lever ratio control open determination speed, and then checks whether vehicle M is traveling straight or turning to the right or left. The driving state of the vehicle, whether it is traveling straight or turning in either direction, is determined based on at least one of the following parameters detected by the parameter detection unit: steering angle, yaw rate, lateral acceleration, etc.

[0047] The stabilizer lever ratio calculation unit 21a then determines the optimal lever ratio λ for the currently running vehicle M based on the steering angular velocity, yaw rate, longitudinal acceleration, number of occupants and their seating positions, the vehicle height at the front and rear of the vehicle which changes depending on the load weight, and tire pressure, all of which are detected by the parameter detection unit 23. The optimal displacement amount of the roll axis G is determined by this lever ratio λ.

[0048] The stabilizer lever ratio calculation unit 21a outputs a drive signal corresponding to the calculated lever ratio λ to the stabilizer motor drive unit 25. The stabilizer motor drive unit 25 rotates the pair of stabilizer drive motors 16 in sync by an angle corresponding to the lever ratio λ, according to the drive signal from the stabilizer lever ratio calculation unit 21a.

[0049] The rotation of each stabilizer drive motor 16 causes the central cylinder portion 14 provided in each stabilizer slide mechanism 12 to rotate. The outer engaging portion 14b of the central cylinder portion 14 engages with the inner engaging portion 15a of the outer cylinder portion 15, restricting axial movement and allowing only rotation in the circumferential direction.

[0050] Therefore, when the central cylinder portion 14 rotates, the stabilizer support cylinder portion 13 moves axially via the male threaded portion 13c that screws into the female threaded portion 14a formed on the inner circumference of the central cylinder portion 14. The stabilizer bar 3a is integrated into the stabilizer support cylinder portion 13. As a result, the stabilizer bar 3a slides together with the stabilizer support cylinder portion 13.

[0051] The following describes the displacement of the roll axis G under the control of the stabilizer lever ratio calculation unit 21a when vehicle M is turning. Note that the following explanation uses the vehicle M turning to the right as an example. For left turns, simply reverse the left and right directions.

[0052] <When the roll axis G is set to the center in the vehicle width direction> As shown in Figures 4 and 7, when the stabilizer lever ratio calculation unit 21a sets the lever ratio λ to the neutral position, the roll axis G is at the center (Y / O) in the vehicle width direction.

[0053] In this state, as shown in Figure 7, when the vehicle M turns to the right, the suspension device 2 on the right wheel 1r side rebounds, and the suspension device 2 on the left wheel 1l side bumps. This creates a difference in the stroke amount of the left and right suspension devices 2. Due to the difference in stroke between the left and right suspension devices 2, torsional stress is generated in the stabilizer bar 3a.

[0054] As a result, a restoring force (reaction force) is applied to the left and right suspension devices 2, as shown by the white arrows in Figure 7, which attempts to correct the twisting of the stabilizer bar 3a. The roll axis G is located at the center of the vehicle M in the width direction (Y / O). Therefore, the left and right suspension devices 2 are subjected to equivalent (symmetrical) reaction forces in opposite directions.

[0055] Therefore, the rebound stroke amount (hereinafter referred to as "rebound amount") ΔZr of the suspension device 2 on the right wheel 1r side and the bump stroke amount (hereinafter referred to as "bump amount") -ΔZl of the suspension device 2 are almost symmetrical. In other words, the absolute values ​​of both strokes ΔZr and -ΔZl, |ΔZr|=|ΔZl|, are almost equal. The roll angle θy is the slope corresponding to the rebound amounts ΔZl and ΔZr of the left and right suspension devices 2.

[0056] <When the roll axis G is displaced toward the inner wheel side of the swing> As shown in Figure 5, when the stabilizer lever ratio calculation unit 21a sets the lever ratio λ such that the stabilizer distance Yr is on the inner wheel side (right wheel 1r direction) of the pivoting wheel than the neutral distance Y0, the stabilizer drive motor 16 slides the stabilizer bar 3a toward the right wheel 1r side.

[0057] Then, the arm portion 3b of the stabilizer bar 3a on the right wheel 1r side presses against one end of the stabilizer link 7 via the ball joint 8. The positional relationship of the stabilizer link 7 with respect to the stabilizer bar 3a and the strut portion of the suspension body is restricted (suspension geometry).

[0058] Therefore, when the arm portion 3b presses against one end of the stabilizer link 7, the stabilizer link 7 rotates the strut portion of the suspension body connected to the other end, or deforms the connecting portion 9. As the strut portion of the suspension body rotates or the connecting portion 9 deforms, one end of the stabilizer link 7 moves closer to the right wheel 1r. This shortens the stabilizer distance Yr.

[0059] On the other hand, the stabilizer bar 3a on the left wheel 1l side has an arm portion 3b that pulls one end of the stabilizer link 7 toward the right wheel 1r via the ball joint 8. As a result, the stabilizer link 7 rotates the strut portion of the suspension body connected to its other end, or deforms the connecting portion 9. Consequently, one end of the stabilizer link 7 moves away from the left wheel 1l, and the stabilizer distance Yl increases (Yr <YO<Yl)。

[0060] As a result, as shown in Figure 5, the center (Y / O') of the stabilizer bar 3a is displaced by (Yo-Yr) from Y / O in Figure 4 towards the right wheel 1r. When the center (Y-O') of the stabilizer bar 3a slides towards the right wheel 1r, the roll axis G of the vehicle M is also displaced towards the center (Y / O') of the stabilizer bar 3a, as shown in Figure 8.

[0061] When vehicle M turns to the right, the suspension device 2 of the right wheel 1r rebounds, and the suspension device 2 of the left wheel 1l bumps, as shown by the solid line in Figure 8. Also, the stabilizer bar 3a tilts together with vehicle M.

[0062] Because the roll axis G is displaced towards the right wheel (inner wheel) 1r side, as shown in Figure 8, the stabilizer bar 3a exerts a stronger reaction force that suppresses the rebound amount ΔZr of the suspension device 2 on the right wheel 1r side. Relatively, the stabilizer bar 3a exerts a weaker reaction force that suppresses the rebound amount ΔZl of the suspension device 2 on the left wheel (outer wheel) 1l side. As a result, the rebound amount ΔZr of the suspension device 2 on the right wheel 1r side is suppressed, and the rebound amount ΔZl of the suspension device 2 on the left wheel 1l side increases. Therefore, the stroke amounts of the left and right suspension devices 2 become asymmetrical (|ΔZr|<|ΔZl|).

[0063] The dashed line in Figure 8 shows the inclination of vehicle M when the roll axis G shown in Figure 7 is set to the center Y / O in the vehicle width direction of vehicle M. Here, for the sake of simplicity, the bump amount -ΔZl on the outer wheel side (left wheel 1l) during turning will be assumed to be the same as in Figure 7.

[0064] By displacing the roll axis G towards the inner turning wheel (right wheel 1r), the rebound amount ΔZr on the inner turning wheel side is suppressed. This allows for quick yawing and achieves high responsiveness. Therefore, this control is suitable for low-riding sports cars and similar vehicles.

[0065] <When the roll axis G is displaced toward the outer wheel side of the swing> As shown in Figure 6, when the stabilizer bar 3a is slid toward the left wheel 1l, the arm portion 3b of the stabilizer bar 3a toward the left wheel 1l presses against one end of the stabilizer link 7 via the ball joint 8.

[0066] In the suspension geometry, when the arm portion 3b presses against one end of the stabilizer link 7, the stabilizer link 7 rotates the strut portion of the suspension body connected to the other end, or deforms the connecting portion 9. As a result, one end of the stabilizer link 7 moves closer to the left wheel 1l. Consequently, the stabilizer distance Yl is shortened.

[0067] On the other hand, on the right wheel 1r side, the arm portion 3b of the stabilizer bar 3a pulls one end of the stabilizer link 7 toward the left wheel 1l via the ball joint 8. As a result, the stabilizer link 7 rotates the strut portion of the suspension body connected to the other end, or deforms the connecting portion 9, moving away from the right wheel 1r. Consequently, the stabilizer distance Yr increases (Yr <YO<Yr)。

[0068] As a result, as shown in Figure 6, the center (Y / O') of the stabilizer bar 3a is displaced by (Yo-Yl) from Y / O in Figure 4 towards the left wheel 1l. When the center (Y-O') of the stabilizer bar 3a slides towards the left wheel 1l, the roll axis G of the vehicle M is also displaced towards the center (Y / O') of the stabilizer bar 3a, as shown in Figure 9.

[0069] When vehicle M turns to the right, the suspension device 2 of the right wheel 1r rebounds and the suspension device 2 of the left wheel 1l bumps, as shown by the solid line in Figure 9. At that time, the stabilizer bar 3a tilts together with vehicle M.

[0070] At this time, since the roll axis G is displaced towards the left wheel 1r, the stabilizer bar 3a exerts a stronger reaction force to suppress the bump amount -ΔZl of the suspension device 2 on the left wheel (outer turning wheel) 1l side. On the other hand, the stabilizer bar 3a exerts a weaker reaction force to suppress the rebound amount ΔZr of the suspension device 2 on the right wheel (inner turning wheel) 1l side.

[0071] As a result, the bump amount -Zl of the suspension device 2 on the left wheel 1l side is suppressed, and the rebound amount ΔZr of the suspension device 2 on the right wheel 1r side increases relatively. Consequently, the stroke amounts of the left and right suspension devices 2 become asymmetrical (|ΔZr|>|ΔZl|).

[0072] The dashed line in Figure 9 shows the tilt of vehicle M when the roll axis G shown in Figure 7 is set to the center Y / O in the vehicle width direction of vehicle M. Here, for the sake of simplicity, the bump amount -ΔZr on the turning inner wheel side (right wheel 1r) will be assumed to be the same as in Figure 7.

[0073] By displacing the roll axis G towards the outer turning wheel (left wheel 1l), the bump amount -ΔZl on the outer turning wheel side is suppressed. Even with the same rebound amount ΔZr as in Figure 7, the suppression of the bump amount -ΔZl increases the amount of understeer (increased steering) of the vehicle M during cornering. This allows the driver to sense that they are exceeding the vehicle speed limit. Therefore, this control is suitable for vehicles with relatively high ground clearance, such as SUVs and minivans, which corner at reduced speeds.

[0074] Thus, in this embodiment, the stabilizer bar 3a is slid to displace the roll axis toward either the inner wheel side or the outer wheel side during cornering. This displacement of the roll axis makes it easy to create an asymmetrical relationship between the rebound stroke amount on the inner wheel side and the bump stroke amount on the outer wheel side during cornering, according to the characteristics of each vehicle model.

[0075] Furthermore, the present invention is not limited to the embodiments described above. For example, the characteristics of the lever ratio λ set by the stabilizer lever ratio calculation unit 21a may be arbitrarily set according to the driver's preference. [Explanation of symbols]

[0076] 1...suspension device, 1l, 1r... left and right front wheels (steering wheels), 2…Suspension system, 2a... Steering knuckle, 3… Stabilizer device, 3a... Stabilizer bar, 3b...arm section, 4... Lower arm, 5... Ball joint, 6... Rubber bushings, 7… Stabilizer link, 8... Ball joint, 9...Connection part, 12… Stabilizer slide mechanism (stabilizer slide mechanism), 13... Stabilizer support cylinder section, 13a...inner cylinder part, 13b...Hard bushing, 13c, 14a... threaded part, 14...middle cylinder part, 14b...Outer engagement part, 15...Outer cylinder part, 15a... Inner engagement portion, 16... Stabilizer drive motor, 16a... Drive gear, 21... Control unit, 21a... Stabilizer lever ratio calculation unit, 22... Auto mode switch, 23...Parameter detection unit, 25... Stabilizer motor drive unit, Y0…neutral distance, Y1...arm distance, Yl, Yr... Stabilization distance, G... Roll axis, M...vehicle, T / O…Center of tire width, Y / O...Center in the vehicle width direction, -ΔZl…Bump amount, ΔZr... Rebound amount, θy...roll angle, λ...Lever ratio

Claims

1. A suspension system that supports the left and right wheels, A stabilizer bar connects the two suspension devices via a stabilizer link. In a vehicle suspension system equipped with, A stabilizer slide mechanism for sliding the aforementioned stabilizer bar, The control unit for the drive of the stabilizer slide mechanism and It further possesses, The control unit, During the vehicle's turning maneuver, the stabilizer bar is slid via the stabilizer slide mechanism to displace the roll axis. A vehicle suspension system characterized by the following:

2. The displacement of the roll axis is set based on the lever ratio, which is the ratio of the distance from the contact point of one of the left or right wheels to the connection point of the stabilizer link with respect to the suspension device to the stabilizer slide mechanism. A vehicle suspension system according to claim 1, characterized in that it is a vehicle suspension system as described in claim 1.

3. The control unit, The turning direction of the vehicle is detected based on at least one of the steering angle, yaw rate, and lateral acceleration, and the lever ratio is set to displace the roll axis toward the inner wheel side in the turning direction. The vehicle suspension system according to claim 2, characterized in that it is a vehicle suspension system.

4. The control unit, The turning direction of the vehicle is detected based on at least one of the steering angle, yaw rate, and lateral acceleration, and the lever ratio is set to displace the roll axis toward the outer wheel side in the turning direction. The vehicle suspension system according to claim 2, characterized in that it is a vehicle suspension system.

5. The stabilizer slide mechanism is arranged in pairs at symmetrical positions on either side of the center of the vehicle's width direction. The drive unit simultaneously drives both stabilizer slide mechanisms to slide the stabilizer bar. A vehicle suspension system according to any one of claims 1 to 4.

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