Dual-rate vehicle suspension system with adjustable ride height

Abstract

To provide a selectively switchable dual mode vehicle suspension system capable of selectively and switchably providing both a low rate, optimal ride comfort setting and a high rate, optimal handling lower ride height setting.SOLUTION: A spring configuration comprises a cylindrical damper (5), a primary coil spring (9) with a first spring rate Kl, and a secondary coil spring (11) with a second spring rate K2. The coil springs are arranged about the cylindrical damper in series so as to provide an overall combined spring rate KT. An actuator (20) is configured to compress and decompress the coil springs. A stop (12) is configured to deactivate the secondary coil spring at a stop position, such that, when the system is in a first comfort mode, the overall spring rate is defined by an equation 1 / KT=1 / Kl+1 / K2, and when the system is in a second handling mode, the overall spring rate is defined by an equation KT=Kl.SELECTED DRAWING: Figure 4C-4D

Description

Technical Field

[0001] The present invention relates to a suspension system for a vehicle, and more particularly to a suspension system that provides two different operating modes. In order to overcome the inherent compromises that must be made between optimizing ride comfort and optimizing the handling capabilities of a road-going vehicle, the present invention provides a dual-mode suspension system that can switch the rate of a primary load coil spring between an optimal handling setting and an optimal ride comfort setting.

Background Art

[0002] The basic premise of an automobile suspension is to allow the vehicle's wheels to independently climb over and traverse road surface disturbances such as bumps and depressions, without moving the entire vehicle and its occupants in such a way. When passengers are not directly affected by road surface disturbances, the ride comfort of the passengers is significantly improved. Also, by only moving the wheels rather than the entire vehicle over road surface disturbances, significant energy savings are realized. Furthermore, since the entire mass of the vehicle does not vertically sway over road surface disturbances, the steering control of the vehicle is significantly improved as the speed increases.

[0003] The suspension of a vehicle can be configured in various ways, but generally, an energy storage medium, usually some kind of spring, is used to arrange the vehicle body main body, called the "sprung mass", to be separated from the wheel system called the "unsprung mass". The spring stores energy so that the wheel system, including the hub, brake, and motion control link mechanism, can move relative to the vehicle body main body in response to road surface disturbances. When passing through the disturbance, the spring releases its stored energy. ​​​​​​​​​​​​​Release it and return the wheel system to a state free from disturbances. To avoid excessive vibration response, some form of damping device is used. Typically, a hydraulic-based damping device is used. The components generate a force proportional to the velocity, providing resistance to the spring motion in both directions, It helps the vehicle return to zero velocity in a position free from disturbances. This damper supports the weight of the vehicle. It is a secondary component.

[0004] As the vehicle approaches the limits of its dynamic response, the motion control linkage mechanism and energy storage and The suspension system, including the component, is designed to reach the optimal performance level. This becomes a limiting factor. To provide a high degree of occupant isolation from road surface disturbances, the springs and dampers are compared. When adjusted to be relatively soft, it responds to the driver's steering, acceleration, and braking requests. The sprung mass tends to move excessively in response to the lateral and longitudinal forces that occur. The requirements for this result in what is generally called "handling response" and the quality of crew separation. This is called "ride response".

[0005] By changing the spring rate (spring constant) and damping coefficient for each of the four wheel corners... This allows for the optimization of the vehicle's ride comfort and handling performance. Generally, A stiffer spring rate, measured by force per unit displacement, results in a firmer ride and superior body control. This results in a softer ride, while a softer spring rate provides a softer ride but reduces controllability. It becomes less effective. The damping coefficient is usually directly matched to the associated spring rate. Unfortunately, optimal A smooth ride response is achieved with a low spring rate, while optimal handling response is achieved with a high spring rate. This occurs at a rate. Historically, this has resulted in vehicles having ride response and handling response. It has been adjusted to meet the compromises of the company.

[0006] Numerous adaptive and manual dual-rate suspension systems described in this technical field There is a system. However, until recently, coil springs, leaf springs, or torsion springs, etc. Is there a metal energy storage device that can provide the required performance characteristics for a vehicle? It was.

[0007] A selectively switchable dual-rate suspension system, according to Holt et al.'s patent. It is described in reference 1. The internal spring structure, which is actuated by a pushrod, is connected to the torsion bar. It includes a series of springs, each with its own spring rate. The ETHA is positioned parallel to the coil spring. In the first mode, the coil spring moves freely. Therefore, the overall spring rate includes the torsion bar spring rate and the coil spring rate. Both contribute. In the second lockout mode, the movement of the coil spring is hindered, The overall spring rate is changed to the torsion bar spring rate. This results in a lower rate With optimal ride height for comfortable settings, and high rate for optimal handling at low ride height Both settings are selectively provided. This selectively switchable dual-rate setting The suspension system is very effective, but it employs a pushrod configuration. Therefore, its use is generally limited to very high-performance vehicles. Consequently, it is not used in a wider range of automobiles. A selectively switchable dual-rate suspension system is needed. Yes, they are. To design a more generally applicable dual-rate suspension system Some attempts have been made. However, none of them are active and selectively switchable systems that provide a lower ride height in the optimal handling mode of a high spring rate. For example, Patent Document 2 of Doerfel describes a non-manually adjustable structure having two coil springs arranged around a strut. The spring assembly has a master spring, a slide, a stopper, and at least one auxiliary spring connected in series with the master spring. During compression of the spring assembly, when the auxiliary spring is compressed to a predetermined point, the stopper contacts the slide to prevent further compression of the auxiliary spring. Another configuration having springs connected in parallel is also described. Similar structures are described in Patent Document 3 of Wakeman and Patent Document 4 of Mason. Neither involves a complete lockout of one spring. Mason attempts to maintain the ride height as a whole, while Wakeman can increase the ride height from the unloaded or neutral state but cannot decrease it. Neither provides a means to lower the ride height in the optimal handling mode of a high spring rate. For example, Patent Document 2 of Doerfel describes a non-manually adjustable structure having two coil springs arranged around a strut. For example, Patent Document 2 of Doerfel describes a non-manually adjustable structure having two coil springs arranged around a strut. For example, Patent Document 2 of Doerfel describes a non-manually adjustable structure having two coil springs arranged around a strut. The spring assembly has a master spring, a slide, a stopper, and at least one auxiliary spring connected in series with the master spring. The spring assembly has a master spring, a slide, a stopper, and at least one auxiliary spring connected in series with the master spring. During compression of the spring assembly, when the auxiliary spring is compressed to a predetermined point, the stopper contacts the slide to prevent further compression of the auxiliary spring. Another configuration having springs connected in parallel is also described. Similar structures are described in Patent Document 3 of Wakeman and Patent Document 4 of Mason. Neither involves a complete lockout of one spring. Mason attempts to maintain the ride height as a whole, while Wakeman can increase the ride height from the unloaded or neutral state but cannot decrease it. Neither provides a means to lower the ride height in the optimal handling mode of a high spring rate. Neither provides a means to lower the ride height in the optimal handling mode of a high spring rate.

Prior Art Documents

Patent Documents

[0008]

Patent Document ](https: / / patents.google.com / patent / US20090302559A1 / en)1

Patent Document 2

Patent Document 3

Patent Document 4

[0009] In a key aspect of the present invention, a selectively switchable dual-rate vehicle suspension The system is conventionally oriented between the unsprung mass and sprung mass at one corner of the vehicle. a cylindrical damper and a primary coil spring having a predetermined first spring rate K1, It includes a secondary coil spring having a predetermined second spring rate K2, and a primary coil spring and The secondary coil springs are arranged in series around the cylindrical damper, and the overall combined spring rate KT The provided spring structure and the configuration for compressing and decompressing the primary coil spring and secondary coil spring. The actuator and the stop are configured to deactivate the secondary coil spring in the stop position. Including the fasteners, when the suspension system is in the first comfort mode, the entire suspension The suspension spring rate is defined by the series equation 1 / KT = 1 / K1 + 1 / K2, and the suspension When the control system is in the second handling mode, the entire vehicle suspension... The rate is defined by the series equation KT=K1, which allows for optimal riding at a low rate. Selectively choose between a comfortable setting and a low ride height setting for optimal handling at a high rate. And it is provided in a switchable format.

[0010] In a further aspect of the present invention, both the primary coil spring and the secondary coil spring are intermediate spring contact portion It connects to the network.

[0011] In a further aspect of the present invention, the actuator has a secondary coil spring via a lower spring contact portion. It acts upon.

[0012] In a further aspect of the present invention, the actuator includes a hydraulic cylinder and a hydraulic piston.

[0013] In a further aspect of the present invention, the secondary coil spring is deactivated when the pressure is reduced.

[0014] In a further aspect of the present invention, the intermediate spring contact portion includes a hydraulic cylinder having a hydraulic piston. nothing.

[0015] In a further aspect of the present invention, the secondary coil spring is deactivated when compressed.

[0016] In a further aspect of the present invention, the hydraulic cylinder moves while being supported by the outer wall of a cylindrical damper.

[0017] In a further aspect of the present invention, the stopper is a cylindrical damper that the contact portion of the hydraulic cylinder abuts against This includes the stopping portion of the exterior wall.

[0018] In a further aspect of the present invention, the suspension system maintains the secondary coil spring in the stop position. Further includes a lockout mechanism configured to hold.

[0019] In a further aspect of the present invention, the suspension system reduces the pressure of the secondary coil spring and the primary The third method involves raising the coil spring to increase the ride height above the optimal ride comfort setting. This includes further control modes.

[0020] In a further aspect of the present invention, the cylindrical damper provides optimal vehicle comfort and handling. Therefore, it provides adjustable damping to adapt to changes in spring rate. [Brief explanation of the drawing]

[0021] [Figure 1A]This is a perspective view of a front assembly single-cylinder system mounted on a conventional double wishbone suspension system, for use in one corner of the vehicle, typically the front corner.

[0022] [Figure 1B] This shows perspective views of the front assembly single-acting cylinder system from various angles. [Figure 1C] This shows perspective views of the front assembly single-acting cylinder system from various angles. [Figure 1D] This shows perspective views of the front assembly single-acting cylinder system from various angles.

[0023] [Figure 2A] This shows a partial elevation and cross-sectional view of a single-acting cylinder system.

[0024] [Figure 2B] A perspective view of part of a single-acting cylinder system and a specific damper component is shown.

[0025] [Figure 3] Figures 3A, 3B, and 3C show multiple elevation views of a front assembly single-acting cylinder system mounted on a conventional double wishbone suspension system in lowered, trimmed, and raised ride height configurations, respectively.

[0026] [Figure 4A-4B] Figures 4A and 4B show the front assembly single-acting cylinder system in a pair of elevation and cross-sectional views and a standard drawing of the system in a lowered vehicle height configuration.

[0027] [Figure 4C-4D] Figures 4C and 4D show the front assembly single-cylinder system in a pair of elevation and section views and a standard drawing of the system in a trimmed ride height configuration.

[0028] [Figure 4E-4F]Figures 4E and 4F show the front assembly single-acting cylinder system in a pair of elevation and cross-sectional views and a standard drawing of the system in a raised vehicle height configuration.

[0029] [Figure 5] Figure 5A shows an alternative front assembly double-acting cylinder system in a perspective view.

[0030] Figure 5B is a partially enlarged view of the alternative front assembly double-cylinder system shown in Figure 5A. The separated portion is shown in an oblique view.

[0031] Figure 5C shows the alternative front assembly double-cylinder system of Figure 5A from a different angle. show.

[0032] [Figure 6] This shows a partial elevation and cross-sectional view of a double-acting cylinder system.

[0033] [Figure 7] Figure 7A shows an elevation view of an alternative front assembly double-cylinder system mounted on a conventional double wishbone suspension system.

[0034] Figure 7B shows a perspective view of an alternative front assembly double-acting cylinder system.

[0035] The embodiments, examples, and alternatives described in the previous paragraph, claims, or the following description and drawings are not applicable. , including any of their various forms or individual features, independently or arbitrarily They can be adopted in combination. Features described in relation to one embodiment are such Applicable to all embodiments, unless the features are incompatible. [Modes for carrying out the invention]

[0036] In the first embodiment, the suspension system 1 includes a front assembly single-acting cylinder The device includes device 3. The cylindrical damper 5, i.e., strut, is a conventional double wishbone. The suspension system provides shock absorption in the 7. A single coil spring is used in the strut. Unlike conventional strut configurations where the struts are mounted coaxially around the torso, typically the struts are mounted differently. Two coil springs with different spring rates are mounted coaxially around a cylindrical damper or strut 5. They are mounted in a row. These are primary coil springs 9 with spring rate K1 and spring rate K2 This is the secondary coil spring 11. A common spring contact portion 13 connects the two coil springs 9 and 11. It plays a supporting role. The primary coil spring 9 is top-mounted at the free end 16 of the strut 5. The lower spring contact portion 17 is distal to the common spring contact portion 13. It is connected to or in contact with the secondary coil spring 11.

[0037] In a spring system containing two springs connected in series, the combined spring rate KT is given by equation 1 / K T is defined by T = 1 / K1 + 1 / K2.

[0038] The hydraulic cylinder actuator 20 has a lower spring contact portion 17 and a non-free end of the cylindrical damper 5. A cylindrical damper 5 is mounted between 21 and the preferred hydraulic cylinder actuator. The actuator is described, but the actuator is any, including electrical, pneumatic, or other. It may include an appropriate mechanism.

[0039] The lower spring contact portion 17 is positioned to rest on the lower suspension component 23. When the coil spring 11 is fully extended and the actuator 20 is retracted, the secondary spring 11 is fully It does not contribute to the body's spring rate KT. In this state, the secondary spring rate K2 is omitted from the equation, The spring rate is defined as 1 / KT = 1 / K1. This is the equivalent spring rate of two springs in series. Because the spring rate is always lower than the single spring rate of either spring alone, a stiffer suspension This is equivalent to a sprint. This also applies to smooth road conditions such as highways or racetracks. This corresponds to a lower ride height for optimal handling. The structure of the thread is shown in Figures 3A, 4A, and 4B.

[0040] When the actuator 20 extends under hydraulic pressure, the spring contact portion 13 at a specific point in time is stopped by the spring retainer 1 Lifted from 2, the secondary coil spring 11 follows the equation 1 / KT = 1 / K1 + 1 / K2 and the whole The actuator 20 compresses the secondary coil spring 11 until it begins to contribute to the spring rate again. This is equivalent to a softer suspension for optimal ride comfort, and is typically This mode is ideal for rougher road conditions. In this mode, the ride height also increases. This is preferable as vehicle clearance from road conditions that may have more uneven surfaces. The appropriate ride height, i.e., the trim mode configuration, is shown in Figures 3B, 4C, and 4D. It is.

[0041] To drive in normal, ever-changing road conditions, the optimal ride comfort settings and height, The trim mode locks the actuator 20 in a specific position relative to the cylindrical damper 5. This can be selected by doing so. In the hydraulic actuator 20 shown in the figure, this is By closing the lubricant 25, the flow of hydraulic fluid 27 entering and leaving the actuator 20 is stopped. And that's achieved.

[0042] Actuator 20 is a hydraulic cylinder slidably sealed to a hydraulic piston 29. 19 may be included, and the hydraulic piston 29 may also slide on the outer wall of the cylindrical damper 5. It is sealed. The position of the hydraulic piston 29 is on the inner wall 35 of the hydraulic cylinder 19, cylindrical The hydraulic fluid in the hydraulic chamber 33 is defined by the outer wall 31 of the compressor 5 and the piston 29. It is determined by the volume. The piston 29 is a cylindrical hydraulic piston 29 and the lower spring contact portion 17. The lower spring contact portion 17 contacts the damper 5 so as to move back and forth in a vertical line. This is possible. As previously shown, the seal 39 enables relatively low-friction reciprocating motion. Furthermore, this prevents leakage of hydraulic fluid between these components. Close valve 25 to reduce hydraulic pressure. The volume of hydraulic fluid in chamber 33 is determined, and the actuator 20 is controlled by the suspension system. It can be locked in a position for trim mode.

[0043] For specific vehicle handling purposes, it is advantageous to further increase the vehicle's height. For example, vehicle If you have to descend a steep private road to enter the main roadway, you need to raise the vehicle's clearance. This may be useful in preventing parts of the vehicle from coming into contact with the private roadway or road surface. Therefore, the actuator 20 can be extended further to raise the front of the vehicle. The system located in a separate elevated position has the following control modes, as shown in Figures 3C, 4E, and 4F. It can be called that. In control mode, the vehicle is not intended to be driven at a considerable speed. While not always the case, it is a useful option under certain conditions.

[0044] In the second embodiment, as shown in Figures 5A-5C, 6, and 7A-7B, the system , including a front assembly double-acting cylinder device. In the first embodiment, the same as a single-acting cylinder device. As shown, the suspension system of the second embodiment has primary and secondary coil springs 9, 11 It includes a cylindrical damper 5 connected in series and coaxially mounted around the cylindrical damper 5. However, in this embodiment, the spring contact portion 13 connecting the coil springs 9 and 11 is also It includes a reciprocating hydraulic cylinder 41 that moves along the cylindrical damper 5. Also, the secondary coil 11 is relative to the suspension component 23 to which the cylindrical damper 5 is attached. , it is fixed at the distal end beyond the spring contact portion 13. In this way, the compression of springs 9 and 11 or The pressure reduction is generated by the hydraulic cylinder 41 from the position between the springs.

[0045] The hydraulic cylinder 41 is positioned to reciprocate along a portion of the outer wall 37 of the cylindrical damper 5. It is attached. The hydraulic chamber is between the hydraulic cylinder 41 and the outer wall 37 of the cylindrical damper 5. It is located on both sides of the piston. By supplying hydraulic fluid to one of the hydraulic chambers 43, 45 The hydraulic cylinder 41 is then biased to move in one direction along the cylindrical damper 5. In the illustrated embodiment, when the hydraulic fluid pressure in the first hydraulic chamber 43 increases, the hydraulic cylinder The 41 compresses the primary coil spring 9, raising the vehicle height. In contrast, the second hydraulic chamber 4 When the hydraulic fluid pressure inside 3 increases, the hydraulic cylinder 41 compresses the secondary coil spring 11, and the vehicle Lower the height. When the vehicle has lowered sufficiently, close valve 25 and the hydraulic chambers 43 and 45 This allows the further flow of hydraulic fluid to be stopped. As a result, the hydraulic cylinder 41 is cylindrical Because it is locked against the damper 5 and its movement is restricted, the secondary coil spring 11 also moves with the entire spring. It is locked out so as not to contribute to the rate KT. In this optimal handling mode, The overall spring rate KT is equal to the primary coil spring rate K1, and the spring rate is given by equation 1 / KT = It is determined by 1 / K1.

[0046] By opening the valve 25, the secondary coil spring 11 can again contribute to the overall spring rate. Then the spring rate is again determined by the formula 1 / KT = 1 / K1 + 1 / K2. In this trim mode, which is the appropriate mode, the hydraulic cylinder 41 controls the primary and secondary coil springs 9. Controlled by compression, the hydraulic fluid moves freely in the longitudinal direction, and the first hydraulic chamber 4 The fluid flows freely between 3 and the second hydraulic chamber 45, and the ride height is optimized for handling. It remains higher than D.

[0047] The outer wall 37 of the cylindrical damper 5 has a wall stopper 4 that abuts against the contact portion 49 of the hydraulic cylinder 41. 7 can be provided. The contact portion 49 is where sufficient hydraulic fluid is pressed into the first hydraulic chamber 43. When it is installed, it comes into contact with the wall stopper 47, which further raises the vehicle height. The operating mode is to close valve 25 and the first hydraulic chamber 43 and the second hydraulic chamber 45 This can be maintained by stopping the flow of hydraulic fluid between them again.

[0048] Of note is the adjustable damping system, along with the suspension system described. When used, it is very beneficial for compensating for changes in spring rate and ride height. That is the case.

[0049] Furthermore, while the illustrated embodiment discloses the arrangement of specific components, other arrangements may be disclosed in this application. It should also be understood that one may benefit from the specification. Specific step sequence The steps are shown, described, and claimed, but unless otherwise indicated, the steps are optional. They may be performed in sequence, separated or combined, and still benefit from the present invention. It should be explained.

[0050] Although different embodiments have specific components shown in the figures, embodiments of the present invention are those Not limited to specific combinations. Some components or features of one embodiment may be used in another. It can be used in combination with the features or components of the embodiment.

[0051] While exemplary embodiments are disclosed, those skilled in the art will know that certain modifications fall within the scope of the claims. They will recognize that. Therefore, consider the following claims and their true scope and The content should be specified.

Claims

1. A selectively switchable dual-rate vehicle suspension system configured to be positioned between the unsprung mass and sprung mass at one corner of the vehicle, Cylindrical damper (5), A primary coil spring (9) having a predetermined first spring rate K1 and a secondary coil spring (11) having a predetermined second spring rate K2, wherein both the primary coil spring (9) and the secondary coil spring (11) are connected to a common spring contact portion (13) and are arranged in series around the cylindrical damper (5) to provide an overall combined spring rate KT. An actuator (20) is attached to the cylindrical damper (5) and configured to compress and depressurize the primary coil spring (9) and the secondary coil spring (11), A stopping means (12) configured to deactivate the secondary coil spring (11) at least one stopping position and Includes, A suspension system in which a first mode of the suspension system, in which the overall suspension spring rate is defined by the series equation 1 / KT = 1 / K1 + 1 / K2, is selected by extending the actuator (20) to compress the primary coil spring (9) and the secondary coil spring (11), and a second mode of the suspension system, in which the overall suspension spring rate is defined by the series equation 1 / KT = 1 / K1, is selected by retracting the actuator (20) to depressurize the primary coil spring (9) and the secondary coil spring (11), thereby selectively and switchably providing both an optimal ride comfort setting at a low rate in the first mode and a low ride height setting with optimal handling at a high rate in the second mode.

2. The suspension system according to claim 1, wherein the actuator (20) includes a hydraulic cylinder (19) and a hydraulic piston (29).

3. The suspension system according to claim 2, wherein the hydraulic piston (29) moves supported by the outer wall of the cylindrical damper (5).

4. The suspension system according to claim 3, wherein the stopping means (12) includes a stopping portion of the outer wall of the cylindrical damper (5) against which the contact portion of the hydraulic piston (29) abuts.

5. The suspension system according to any one of claims 1 to 4, wherein the actuator (20) acts on the secondary coil spring (11) via the lower spring contact portion (17).

6. The suspension system according to any one of claims 1 to 5, wherein the secondary coil spring (11) is deactivated when the pressure is reduced.

7. The suspension system according to any one of claims 1 to 6, further comprising a third operating mode, in which both the secondary coil spring (11) and the primary coil spring (9) are raised beyond the first mode, thereby increasing the ride height of the vehicle beyond the ride height in the optimal ride comfort setting of the first mode.

8. The suspension system according to any one of claims 1 to 7, wherein the cylindrical damper (5) provides adjustable damping to adapt to changes in spring rate for optimal vehicle comfort and handling.

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