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 in particular to a suspension system that provides two different operating modes. The suspension system provides optimal ride comfort and handling for road vehicles. To overcome the inherent compromise that must be made between optimizing performance and Primary load coil spring rate is set for optimum handling and optimum ride comfort. To provide a dual mode suspension system that can be switched between [Background technology]

[0002] The basic premise of an automobile suspension is that the wheels of a vehicle are able to independently ride on uneven road surfaces. to enable the whole vehicle and its occupants to move up or across the If passengers are not directly affected by road disturbances, passenger comfort is greatly improved. Also, by moving the wheels over road disturbances instead of the entire vehicle, significant energy savings can be achieved. In addition, the vehicle's steering is improved because the entire mass of the vehicle does not pitch over road disturbances. Alignment control improves significantly with increasing speed.

[0003] Vehicle suspensions can be configured in a variety of ways, but generally include an energy storage medium Usually, some kind of spring is used to separate the vehicle body, called the "sprung mass," from the "unsprung mass." The springs are arranged so that they are separate from the wheel system, which is called the hub, brake, and running gear. The wheel system including the dynamic control link mechanism can move relative to the vehicle body in response to road disturbances. When the disturbance passes, the spring releases the stored energy. The wheel system is returned to a disturbance-free state by releasing the force. To avoid a sudden vibration response some form of damping device is used, usually hydraulically based. The components generate a force proportional to the velocity to provide resistance in both directions of spring motion, This damper helps the suspension return to zero speed at a disturbance-free position. It is a secondary component.

[0004] As the vehicle approaches the limits of its dynamic response, the motion control linkages and energy storage and dynamics Suspension systems, including damper components, are designed to help achieve optimal performance levels. To provide a high degree of occupant isolation from road disturbances, the springs and dampers are compared. When adjusted relatively softly, the steering, acceleration and braking demands of the driver cause the These tend to cause excessive movement of the sprung mass in response to the lateral and longitudinal forces that arise. The requirements for this result in what is commonly called "handling response" and the quality of occupant separation. is called "Ride Response."

[0005] You can change the spring rate and damping coefficient at each of the four wheel corners. By doing so, the ride comfort and handling performance of the vehicle can be optimized. Stiffer spring rates, measured in force per unit displacement, give a firmer ride and better body control whereas a softer spring rate provides a softer ride but less control. Damping coefficients are usually directly matched to the associated spring rate. A smooth ride response occurs with a low spring rate, while optimal handling response occurs with a high spring rate. Historically, this has resulted in vehicles being unable to maintain their ride and handling response. It has been adjusted according to the compromise points of S.

[0006] There are a number of adaptive and manual dual-rate suspension systems described in the art. However, until recently, there has been none that can provide the required performance vehicle characteristics using a metal energy storage device such as a coil spring, leaf spring, or torsion spring. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. None has been able to.

[0007] A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. A selectable dual-rate suspension system is described in Patent Document 1 by Holt et al. An inner spring structure actuated by a push rod includes a torsion bar and a coil spring in series, each having its own spring rate. A lockout actuator is disposed parallel to the coil spring. In the first mode, the coil spring can move freely, so both the torsion bar spring rate and the coil spring rate contribute to the overall spring rate. In the second lockout mode, the movement of the coil spring is restricted and the overall spring rate is changed to the spring rate of the torsion bar. This provides both a comfortable setting with an optimal ride height at a low rate and an optimal handling setting with a low ride height at a high rate. This selectable dual-rate suspension system is very effective, but due to its push rod configuration, it is generally limited in use to very high-performance vehicles. Therefore, there is a need for a more widely applicable selectable dual-rate suspension system. is needed. To design a more generally applicable dual-rate suspension system, several Some attempts have been made. However, none of them are active and selectively switchable systems that can provide a lower ride height in the optimal handling mode with 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 overall, 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 with a high spring rate. able system. 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 overall, 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 with a high spring rate.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

SUMMARY OF THE INVENTION

MEANS FOR SOLVING THE PROBLEM

[0009] In a main aspect of the present invention, a selectively switchable dual-rate vehicle suspension system is conventionally oriented between the unsprung mass and the sprung mass at one corner of the vehicle , including a cylindrical damper, a primary coil spring having a predetermined first spring rate K1, and a secondary coil spring having a predetermined second spring rate K2, wherein the primary coil spring and the secondary coil spring are arranged in series around the cylindrical damper to provide an overall combined spring rate KT spring structure, an actuator configured to compress and decompress the primary coil spring and the secondary coil spring, and a stopper configured to deactivate the secondary coil spring in a stop position, and when the suspension system is in a first comfort mode, the overall suspension spring rate is defined by the series equation 1 / KT = 1 / K1 + 1 / K2, and when the suspension system is in a second handling mode, the overall vehicle suspension spring rate is defined by the series equation KT = K1, thereby selectively providing both an optimal ride comfort setting at a low rate and an optimal handling low ride height setting at a high rate and being switchable.

[0010] In a further aspect of the present invention, both the primary coil spring and the secondary coil spring are connected to an intermediate spring abutment.

[0011] In a further aspect of the present invention, the actuator acts on the secondary coil spring via a lower spring abutment.

[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 depressurized.

[0014] In a further aspect of the present invention, the intermediate spring abutment includes a hydraulic cylinder having a hydraulic piston. including.

[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 is supported and moved on the outer wall of the cylindrical damper.

[0017] In a further aspect of the present invention, the stopper includes a stop portion on the outer wall of the cylindrical damper against which the contact portion of the hydraulic cylinder abuts. including.

[0018] In a further aspect of the present invention, the suspension system further includes a lockout means configured to hold the secondary coil spring in the stopped position. including.

[0019] In a further aspect of the present invention, the suspension system further includes a third operating mode for depressurizing the secondary coil spring and raising the primary coil spring to increase the ride height above the optimal ride comfort setting. Including. including.

[0020] In a further aspect of the present invention, the cylindrical damper provides adjustable damping adapted to changes in spring rate for optimal vehicle comfort and handling. including.

Brief Description of the Drawings

[0021]

Figure 1A

[0022]

Figure 1B

Figure 1C

Figure 1D

[0023]

Figure 2A

[0024]

Figure 2B

[0025]

Figure 3

[0026]

Figure 4A - 4B

[0027]

Figure 4C - 4D

[0028]

Figure 4E - 4F

[0029]

Figure 5

[0030] Figure 5B shows a partially enlarged section of the alternative front assembly double-acting cylinder system of Figure 5A in a perspective exploded view.

[0031] Figure 5C shows the alternative front assembly double-acting cylinder system of Figure 5A from another angle showing.

[0032]

Figure 6

[0033]

Figure 7

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

[0035] The previous paragraphs, claims, or the embodiments, examples, and alternatives of the following description and drawings may be employed independently or in any combination, including any of their various aspects or each of their individual features. Features described in connection with one embodiment are applicable to all embodiments as long as such features are not incompatible.

Mode for Carrying Out the Invention

[0036] In the first embodiment, the suspension system 1 includes a front assembly single-acting cylinder device 3. The cylindrical damper 5, i.e., the strut, provides shock absorption in a conventional double wishbone suspension system 7. Unlike a conventional strut arrangement where a single coil spring is coaxially attached around the strut, typically two coil springs with different spring rates are coaxially mounted in series around the cylindrical damper or strut 5. These are the primary coil spring 9 with a spring rate K1 and the secondary coil spring 11 with a spring rate K2. A common spring abutment 13 serves to connect the two coil springs 9, 11. The primary coil spring 9 is connected to, or abuts against, the top mount 15 at the free end 16 of the strut 5. The lower spring abutment 17 is connected to, or abuts against, the secondary coil spring 11 distal from the common spring abutment 13. In a spring system including two springs connected in series, the combined spring rate KT is defined by the formula 1 / KT = 1 / K1 + 1 / K2.

[0037] An hydraulic cylinder actuator 20 is mounted around the cylindrical damper 5 between the lower spring abutment 17 and the non-free end 21 of the cylindrical damper 5. Although a preferred hydraulic cylinder actuator is described, the actuator can include any

[0038] suitable mechanism including electrical, pneumatic, or others. When the secondary coil spring 11 is fully extended such that the lower spring abutment 17 rests on the lower suspension component 23 and the actuator 20 is retracted, the secondary spring 11 is fully

[0039] extended and the actuator 20 is retracted, the secondary spring 11 is fully ​​​It does not contribute to the body spring rate KT. In this state, the secondary spring rate K2 drops out of the equation, and the spring rate is defined as 1 / KT = 1 / K1. This corresponds to a stiffer suspension because the combined spring rate of two springs in series is always lower than the single spring rate of either one of the springs. This also corresponds to a lower ride height for optimal handling on road conditions such as smooth highways or race tracks. This lower ride height configuration is shown in FIGS. 3A, 4A, and 4B. When the actuator 20 extends under hydraulic pressure, at a certain point the spring contact portion 13 lifts off the spring stop 12, and the actuator 20 compresses the secondary coil spring 11 until the secondary coil spring 11 begins to contribute again to the overall spring rate according to the equation 1 / KT = 1 / K1 + 1 / K2. This corresponds to a softer suspension for optimal ride comfort, typically optimal in more bumpy road conditions. In this mode, the ride height also increases, which is preferable as vehicle clearance from more potentially bumpy road conditions. This comfortable ride height, i.e., the trim mode configuration, is shown in FIGS. 3B, 4C, and 4D. For driving in normal variable road conditions, the optimal ride comfort setting and height, i.e., the trim mode, can be selected by locking the actuator 20 in a specific position relative to the cylindrical damper 5. In the illustrated hydraulic actuator 20, this is achieved by closing the valve 25 to stop the flow 27 of hydraulic fluid entering and leaving the actuator 20. This does not contribute to the body spring rate KT. In this state, the secondary spring rate K2 drops out of the equation, and the spring rate is defined as 1 / KT = 1 / K1. This corresponds to a stiffer suspension because the combined spring rate of two springs in series is always lower than the single spring rate of either one of the springs. This also corresponds to a lower ride height for optimal handling on road conditions such as smooth highways or race tracks. This lower ride height configuration is shown in FIGS. 3A, 4A, and 4B. When the actuator 20 extends under hydraulic pressure, at a certain point the spring contact portion 13 lifts off the spring stop 12, and the actuator 20 compresses the secondary coil spring 11 until the secondary coil spring 11 begins to contribute again to the overall spring rate according to the equation 1 / KT = 1 / K1 + 1 / K2. This corresponds to a softer suspension for optimal ride comfort, typically optimal in more bumpy road conditions. In this mode, the ride height also increases, which is preferable as vehicle clearance from more potentially bumpy road conditions. This comfortable ride height, i.e., the trim mode configuration, is shown in FIGS. 3B, 4C, and 4D. For driving in normal variable road conditions, the optimal ride comfort setting and height, i.e., the trim mode, can be selected by locking the actuator 20 in a specific position relative to the cylindrical damper 5. In the illustrated hydraulic actuator 20, this is achieved by closing the valve 25 to stop the flow 27 of hydraulic fluid entering and leaving the actuator 20.

[0040] When the actuator 20 extends under hydraulic pressure, at a certain point the spring contact portion 13 lifts off the spring stop 12, and the actuator 20 compresses the secondary coil spring 11 until the secondary coil spring 11 begins to contribute again to the overall spring rate according to the equation 1 / KT = 1 / K1 + 1 / K2. This corresponds to a softer suspension for optimal ride comfort, typically optimal in more bumpy road conditions. In this mode, the ride height also increases, which is preferable as vehicle clearance from more potentially bumpy road conditions. This comfortable ride height, i.e., the trim mode configuration, is shown in FIGS. 3B, 4C, and 4D. For driving in normal variable road conditions, the optimal ride comfort setting and height, i.e., the trim mode, can be selected by locking the actuator 20 in a specific position relative to the cylindrical damper 5. In the illustrated hydraulic actuator 20, this is achieved by closing the valve 25 to stop the flow 27 of hydraulic fluid entering and leaving the actuator 20. This does not contribute to the body spring rate KT. In this state, the secondary spring rate K2 drops out of the equation, and the spring rate is defined as 1 / KT = 1 / K1. This corresponds to a stiffer suspension because the combined spring rate of two springs in series is always lower than the single spring rate of either one of the springs. This also corresponds to a lower ride height for optimal handling on road conditions such as smooth highways or race tracks. This lower ride height configuration is shown in FIGS. 3A, 4A, and 4B. When the actuator 20 extends under hydraulic pressure, at a certain point the spring contact portion 13 lifts off the spring stop 12, and the actuator 20 compresses the secondary coil spring 11 until the secondary coil spring 11 begins to contribute again to the overall spring rate according to the equation 1 / KT = 1 / K1 + 1 / K2. This corresponds to a softer suspension for optimal ride comfort, typically optimal in more bumpy road conditions. In this mode, the ride height also increases, which is preferable as vehicle clearance from more potentially bumpy road conditions. This comfortable ride height, i.e., the trim mode configuration, is shown in FIGS. 3B, 4C, and 4D. For driving in normal variable road conditions, the optimal ride comfort setting and height, i.e., the trim mode, can be selected by locking the actuator 20 in a specific position relative to the cylindrical damper 5. In the illustrated hydraulic actuator 20, this is achieved by closing the valve 25 to stop the flow 27 of hydraulic fluid entering and leaving the actuator 20. This does not contribute to the body spring rate KT. In this state, the secondary spring rate K2 drops out of the equation, and the spring rate is defined as 1 / KT = 1 / K1. This corresponds to a stiffer suspension because the combined spring rate of two springs in series is always lower than the single spring rate of either one of the springs. This also corresponds to a lower ride height for optimal handling on road conditions such as smooth highways or race tracks. This lower ride height configuration is shown in FIGS. 3A, 4A, and 4B. When the actuator 20 extends under hydraulic pressure, at a certain point the spring contact portion 13 lifts off the spring stop 12, and the actuator 20 compresses the secondary coil spring 11 until the secondary coil spring 11 begins to contribute again to the overall spring rate according to the equation 1 / KT = 1 / K1 + 1 / K2. This corresponds to a softer suspension for optimal ride comfort, typically optimal in more bumpy road conditions. In this mode, the ride height also increases, which is preferable as vehicle clearance from more potentially bumpy road conditions. This comfortable ride height, i.e., the trim mode configuration, is shown in FIGS. 3B, 4C, and 4D. For driving in normal variable road conditions, the optimal ride comfort setting and height, i.e., the trim mode, can be selected by locking the actuator 20 in a specific position relative to the cylindrical damper 5. In the illustrated hydraulic actuator 20, this is achieved by closing the valve 25 to stop the flow 27 of hydraulic fluid entering and leaving the actuator 20.

[0041] For driving in normal variable road conditions, the optimal ride comfort setting and height, i.e., the trim mode, can be selected by locking the actuator 20 in a specific position relative to the cylindrical damper 5. In the illustrated hydraulic actuator 20, this is achieved by closing the valve 25 to stop the flow 27 of hydraulic fluid entering and leaving the actuator 20. This does not contribute to the body spring rate KT. In this state, the secondary spring rate K2 drops out of the equation, and the spring rate is defined as 1 / KT = 1 / K1. This corresponds to a stiffer suspension because the combined spring rate of two springs in series is always lower than the single spring rate of either one of the springs. This also corresponds to a lower ride height for optimal handling on road conditions such as smooth highways or race tracks. This lower ride height configuration is shown in FIGS. 3A, 4A, and 4B. When the actuator 20 extends under hydraulic pressure, at a certain point the spring contact portion 13 lifts off the spring stop 12, and the actuator 20 compresses the secondary coil spring 11 until the secondary coil spring 11 begins to contribute again to the overall spring rate according to the equation 1 / KT = 1 / K1 + 1 / K2. This corresponds to a softer suspension for optimal ride comfort, typically optimal in more bumpy road conditions. In this mode, the ride height also increases, which is preferable as vehicle clearance from more potentially bumpy road conditions. This comfortable ride height, i.e., the trim mode configuration, is shown in FIGS. 3B, 4C, and 4D. For driving in normal variable road conditions, the optimal ride comfort setting and height, i.e., the trim mode, can be selected by locking the actuator 20 in a specific position relative to the cylindrical damper 5. In the illustrated hydraulic actuator 20, this is achieved by closing the valve 25 to stop the flow 27 of hydraulic fluid entering and leaving the actuator 20. This does not contribute to the body spring rate KT. In this state, the secondary spring rate K2 drops out of the equation, and the spring rate is defined as 1 / KT = 1 / K1. This corresponds to a stiffer suspension because the combined spring rate of two springs in series is always lower than the single spring rate of either one of the springs. This also corresponds to a lower ride height for optimal handling on road conditions such as smooth highways or race tracks. This lower ride height configuration is shown in FIGS. 3A, 4A, and 4B.

[0042] The actuator 20 can include a hydraulic cylinder 19 that is slidably sealed to a hydraulic piston 29, and the hydraulic piston 29 is similarly slidably sealed to the outer wall of the cylindrical damper 5. The position of the hydraulic piston 29 is determined by the volume of the hydraulic fluid in the hydraulic chamber 33 defined by the inner wall 35 of the hydraulic cylinder 19, the outer wall 31 of the cylindrical damper 5, and the piston 29. The piston 29 can contact the lower spring abutment 17 such that the hydraulic piston 29 and the lower spring abutment 17 reciprocate in a vertical row with respect to the cylindrical damper 5. As shown previously, the seal 39 allows for a relatively low-friction reciprocating motion while preventing leakage of the hydraulic fluid between these components. Closing the valve 25 defines the volume of the hydraulic fluid in the hydraulic chamber 33 and can lock the actuator 20 in a position for the trim mode of the suspension system. For certain vehicle handling purposes, it is advantageous to further increase the vehicle height. For example, when the vehicle has to descend a steep private driveway to enter the road lane, increasing the vehicle height can be beneficial to prevent a part of the vehicle from contacting the private driveway or the road surface. In this situation, the actuator 20 can be further extended to raise the front of the vehicle. The system in this particularly raised position can be called a handling mode as shown in FIGS. 3C, 4E, and 4F. It is not intended to drive the vehicle at a significant speed in the handling mode, but it is a useful option under certain conditions. In a second embodiment, as shown in FIGS. 5A - 5C, 6, and 7A - 7B, the system

[0043]

[0044] ​​​​​​​​​​​​​​​, including a front assembly double-acting cylinder device. The first embodiment, like the single-acting cylinder device, Similarly, the suspension system of the second embodiment includes a cylindrical damper 5 in which primary and secondary coil springs 9, 11 are connected in series and coaxially mounted around the cylindrical damper 5. However, in this embodiment, the spring abutment portion 13 connecting the coil springs 9, 11 also includes a reciprocating hydraulic cylinder 41 that moves along the cylindrical damper 5. Also, the secondary coil spring 11 is fixed to the suspension component 23 to which the cylindrical damper 5 is attached at a distal end farther from the spring abutment portion 13. In this way, compression or decompression of the springs 9, 11 is generated from a position between the springs by the hydraulic cylinder 41.

[0045] The hydraulic cylinder 41 is attached to reciprocate along a part of the outer wall 37 of the cylindrical damper 5. The hydraulic chambers are on both sides of the piston between the hydraulic cylinder 41 and the outer wall 37 of the cylindrical damper 5. By supplying hydraulic fluid to one of the hydraulic chambers 43, 45, the hydraulic cylinder 41 is 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 41 compresses the primary coil spring 9 and raises the vehicle height. In contrast, when the hydraulic fluid pressure in the second hydraulic chamber 4 3 increases, the hydraulic cylinder 41 compresses the secondary coil spring 11 and lowers the vehicle height. When the vehicle has sufficiently descended, the valve 25 can be closed to stop further flow of the hydraulic fluid in the hydraulic chambers 43, 45. Thereby, the hydraulic cylinder 41 is locked to the cylindrical damper 5 and its movement is restricted, so that the secondary coil spring 11 is also the overall 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 the formula 1 / KT = 1 / K1.

[0046] When the valve 25 is opened and the secondary coil spring 11 can contribute to the overall spring rate again the spring rate is again determined by the formula 1 / KT = 1 / K1 + 1 / K2. In this trim mode which is the optimal comfort mode, the hydraulic cylinder 41 is controlled by the compression of the primary and secondary coil springs 9, 11 to move freely in the vertical direction, and the hydraulic fluid flows freely between the first hydraulic chamber 4 3 and the second hydraulic chamber 45, and the ride height remains higher than in the optimal handling mode by.

[0047] On the outer wall 37 of the cylindrical damper 5, a wall stop 4 7 can be provided that abuts against the contact portion 49 of the hydraulic cylinder 41. When sufficient hydraulic fluid is pushed into the first hydraulic chamber 43, the contact portion 49 abuts against the wall stop 47, thereby further increasing the vehicle height. This increased height operating mode can be maintained by closing the valve 25 and stopping the flow of hydraulic fluid between the first hydraulic chamber 43 and the second hydraulic chamber 45 again.

[0048] It should be noted that an adjustable damping system is very beneficial for correcting changes in spring rate and ride height when used together with the described suspension system as described.

[0049] Also, although the arrangement of specific components is disclosed in the illustrated embodiment, it should also be understood that other arrangements will benefit from the present application specification. A specific step sequence​​ is shown, described, and claimed, but unless otherwise indicated, the steps may be performed in any order, may be separated or combined, and it should be understood that one can still obtain benefits from the present invention.

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

[0051] Exemplary embodiments are disclosed, but those skilled in the art will recognize that certain modifications are within the scope of the claims. Therefore, the following claims should be considered to determine the true scope and content thereof. ​​

Claims

1. A selectively switchable dual rate vehicle suspension system, comprising: A spring structure configured to be disposed between the unsprung mass and the sprung mass at one corner. a cylindrical damper and a primary coil spring having a first predetermined spring rate K1 and a secondary coil spring having a second predetermined spring rate K2, The coil spring and the secondary coil spring are arranged in series around the cylindrical damper to form an overall a spring structure providing a composite spring rate KT; an actuator configured to compress and decompress the primary coil spring and the secondary coil spring; With Chueta, a stop configured to deactivate the secondary coil spring at a stop position; and Including, When the suspension system is in a first mode, the total suspension spring load is The suspension is defined by the series equation 1 / KT = 1 / K1 + 1 / K2. When the system is in the second mode, the overall vehicle suspension spring rate is given by the series equation KT = K1, which provides optimal ride at low rates in the first mode. Low ride height for optimal handling with comfort setting and high rate in the second mode A suspension system that provides both selective and switchable settings.

2. Both the primary coil spring and the secondary coil spring are connected to an intermediate spring abutment.

2. The suspension system according to claim 1.

3. The actuator acts on the secondary coil spring via a lower spring abutment. Item 3. The suspension system according to item 1 or 2.

4. 4. The suspension of claim 3, wherein the actuator includes a hydraulic cylinder and a hydraulic piston. Pension system.

5. 5. The method of claim 1, wherein the secondary coil spring is deactivated when pressure is reduced.

2. The suspension system of claim 1.

6. 3. The spring of claim 2, wherein the intermediate spring abutment comprises a hydraulic cylinder having a hydraulic piston. Suspension system.

7. 7. The suspension of claim 6, wherein the secondary coil spring is deactivated when compressed. tion system.

8. The damper according to claim 7, wherein the hydraulic cylinder moves while being supported by an outer wall of the cylindrical damper. Suspension system.

9. The stopper is a stopper for the outer wall of the cylindrical damper against which the contact portion of the hydraulic cylinder abuts. The suspension system of claim 8 comprising a portion.

10. a lockout means configured to hold the secondary coil spring in the stop position; 10. The suspension system according to claim 6, further comprising:

11. The method further includes a third steering mode, wherein the secondary coil spring is decelerated in the third steering mode. The primary coil spring is then compressed to raise the ride height above the optimum ride comfort setting.

7. The suspension system of claim 6, wherein the suspension is increased upward.

12. The cylindrical damper allows for variable spring rate for optimal vehicle comfort and handling.

12. The method according to claim 1, further comprising adjusting damping to suit the change in temperature. Suspension system.

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