Suspension system for varying a spring rate of the suspension system and method for varying a spring rate of a suspension system

Abstract

The present invention relates to a suspension system for varying a spring rate of the suspension system, in particular for electromechanically varying the spring rate of the suspension system, comprising: a piston-cylinder arrangement with at least one piston that is movable in a cylinder; a first coil spring and a second coil spring that are arranged in series along the piston-cylinder arrangement; an axially movable first spring plate that has a first side and a second side, the first side supporting the first coil spring and the second side supporting the second coil spring; and a first adjusting element that is designed to axially lock the first spring plate relative to the cylinder in a locked state. Furthermore, the present invention relates to a vehicle and a method for varying a spring rate of a suspension system.

Description

Technical area

[0001] The present invention relates to a suspension system for varying a spring rate of the suspension system, in particular a suspension system for electromechanically varying the spring rate of the suspension system, a vehicle having such a suspension system and a method for varying a spring rate of a suspension system. background

[0002] Conventional suspension systems, such as those used in vehicles such as automobiles, typically comprise a damper and a compression spring. The spring stores energy when the wheel system—which includes a hub, brake, and motion control linkage—is allowed to move relative to the vehicle body in response to road disturbances. After overcoming a disturbance, the spring releases its stored energy to return the wheel system to its undisturbed state. The compression spring generates a force proportional to its deflection but does not dissipate energy.

[0003] A suspension system equipped with only an energy storage element exhibits uncontrolled vibration behavior, familiar from the physics of simple spring-mass systems. Without any form of damping, a disturbed spring-mass system will continue to oscillate unless external forces are applied. In a vehicle suspension system, these dissipative forces are typically generated by some type of damping device, most often a hydraulic component that generates a force proportional to the velocity. In this way, the damper provides a resistive force in both directions of spring movement and therefore brings the spring to zero velocity in the undisturbed position. It is important to note that the damper is a purely secondary component of the suspension, as it cannot support the body; this primary function is performed by the spring.

[0004] Typically, the damping coefficient of a passive damper and the spring rate of a coil spring are often fixed and thus not adjustable once the shock absorber is fully assembled. While it is known that a stiffer spring (i.e., a larger spring rate or spring constant) allows the spring to return to its original state more quickly after compression, it is also known that a softer spring (i.e., a smaller or lower spring rate or spring constant) absorbs energy over a longer distance, thereby mitigating disturbances.

[0005] Document EP 3 400 142 A1 describes a dual-mode suspension system in which the rate of the primary road spring can be switched between an optimal handling setting and an optimal ride comfort setting. The dual-mode suspension system comprises a double wishbone suspension system with a tappet-actuated inboard spring configuration conventionally aligned between the unsprung mass and the sprung mass of a corner of the vehicle and comprising a torsion bar spring with a first predetermined rate, K1, and a coil spring with a second predetermined rate, K2. Furthermore, document US 2011 / 0291338 A1 describes a dual spring arrangement for varying the combined resultant spring rate of the arrangement when the dual springs are compressed.Once the applied loads exceed the first amplitude of the applied load and once an amount of preload in the spring is overcome at the second spring rate, the dual spring assembly operates at a lower "effective" spring rate to absorb the energy of the applied loads that exceed the first amplitude of the applied load. Disclosure of the invention

[0006] Therefore, solutions must be found to change the spring rate of a suspension system quickly and easily while driving.

[0007] To this end, the present invention provides a suspension system according to claim 1, a vehicle according to claim 12 and a method according to claim 13.

[0008] According to a first aspect of the invention, a suspension system for varying a spring rate of the suspension system, in particular for electromechanically varying the spring rate of the suspension system, is provided. The suspension system comprises a piston-cylinder arrangement with at least one piston movable in a cylinder; and a first coil spring and a second coil spring arranged in series along the piston-cylinder arrangement. Furthermore, the suspension system comprises an axially movable first spring plate having a first side and a second side. The first side supports the first coil spring, and the second side supports the second coil spring. Furthermore, the suspension system comprises a first adjustment element configured to axially lock the first spring plate relative to the cylinder in a locked state.

[0009] According to a second aspect of the invention, a vehicle, in particular a motor vehicle, is provided with a suspension system according to the first aspect of the invention.

[0010] According to a third aspect of the invention, a method for varying a spring rate of a suspension system is provided. The method comprises axially locking an axially movable first spring plate relative to a cylinder in a locked state, the first spring plate having a first side and a second side. The first side supports a first coil spring, and the second side supports a second coil spring. In particular, a method for varying a spring rate of a suspension system according to the first aspect of the invention is provided.

[0011] One idea of ​​the present invention is to provide a suspension system for a vehicle, wherein a spring rate of the suspension system can be selected as needed. That is, in the locked or blocked state, only the first coil spring is active. Therefore, a spring rate of the suspension system in the locked state essentially corresponds to a stiffness of the first coil spring. The locked state can be used, for example, as a sport state to improve body control. The sport state could be suitable for a racetrack and requires a higher spring rate. In contrast to the locked state, an unlocked or unlocked state can be used as a comfort state to reduce body accelerations. The comfort state can be suitable for daily use and requires a lower spring rate. In the unlocked state, the first coil spring and the second coil spring are active.Therefore, the spring rate of the suspension system is a combination of the stiffness of the first coil spring and the stiffness of the second coil spring in the unlocked state. The first coil spring and the second coil spring are separated by the first spring plate. The first spring plate can slide along the cylinder.

[0012] In particular, the suspension system can be based on a McPherson strut. Furthermore, the spring rate of the suspension system can be manually selected by an electromechanical actuation system. Alternatively, the spring rate of the suspension system can be selected automatically or semi-automatically to initiate the electromechanical change in the spring rate.

[0013] The vehicle within the meaning of this application can be a two-wheeler such as a bicycle, a car, a truck, or similar. In particular, the vehicle is designed as a motor vehicle.

[0014] The method can also be applied in reverse to move the suspension system from the locked state to the unlocked state. Specifically, the axially locked first spring plate would be axially unlocked relative to the cylinder.

[0015] Consequently, the present invention provides a more cost-effective and lightweight solution compared to technologies with comparable functionalities, such as air suspension or a two-stage vehicle suspension system. A further advantage of the present invention is that the installation space, the weight of the components used, and / or the manufacturing costs can be reduced, particularly compared to air suspension. Furthermore, the energy consumption of the motor vehicle can be reduced, particularly compared to air suspension.

[0016] It is understood that the term "vehicle" or "transportation," or a similar term, as used herein, encompasses motor vehicles in general, such as passenger cars, including sport utility vehicles (SUVs), buses, trucks, various commercial vehicles, and the like, as well as hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative-fuel vehicles (e.g., fuels derived from resources other than petroleum). A hybrid vehicle is a vehicle that has two or more power sources, such as both gasoline-powered and electric-powered vehicles.

[0017] Advantageous embodiments and further developments of the present invention are contained in the subordinate claims.

[0018] According to one embodiment of the invention, the first adjustment element is arranged on the second side of the first spring plate and is designed to limit an axial movement of the first spring plate relative to the cylinder to one side in an unlocked state.

[0019] According to a further embodiment of the invention, the suspension system further comprises an axially movable second spring plate supporting the second coil spring and a second adjustment element configured to limit axial movement of the second spring plate relative to the cylinder. The first and / or second adjustment element may, for example, be configured as an adjustment plate.

[0020] According to a further embodiment of the invention, the second adjustment element has at least one ramp protruding in the direction of the second spring plate, and wherein the second spring plate has at least one ramp protruding in the direction of the second adjustment element and corresponding thereto, such that the at least one ramp of the second adjustment element and the second spring plate can be brought into engagement with one another. By pivoting the second adjustment element, the second spring plate is thus moved axially in the direction of the first spring plate, since the at least one ramp of the second adjustment element and the second spring plate slide relative to one another. A pitch of the at least one ramp depends on the stiffness of the first and second coil springs.

[0021] Alternatively or additionally, the height of the at least one ramp can depend on the necessary displacement of the first spring plate in the direction of the longitudinal axis in order to achieve a locking position of the first spring plate or the locked state. In other words, the size and shape of the at least one ramp must be defined according to the required spring travel and the coil spring stiffness used. The axial movement of the second spring plate generates an impact on the second coil spring and therefore also moves the first spring plate. When the first spring plate is locked by the first adjustment element, the second adjustment element is pivoted back and the second spring plate moves away from the first spring plate.

[0022] According to a further embodiment of the invention, at least one of the two adjustment elements is pivotable about a longitudinal axis of the first or second spring plate and relative thereto. For example, at least one of both the first and the second adjustment elements is pivotable relative to the first or second spring plate within a range of up to 180°, preferably within a range of approximately 15° to 90°, particularly preferably within a range of approximately 30° to 90°, in particular approximately 45°. The first and / or the second adjustment element can be pivotable in only one direction or in both directions.

[0023] According to a further embodiment of the invention, the first spring plate is axially locked in the locked state by pivoting the first adjusting element relative to the first spring plate.

[0024] According to a further embodiment of the invention, at least one of the two adjusting elements comprises a gear, in particular a serrated gear, by means of which the first and / or the second adjusting element can be pivoted.

[0025] According to a further embodiment of the invention, the suspension system further comprises an actuator for pivoting at least one of the two adjustment elements. The actuator can be configured as a stepper motor or the like. Furthermore, the actuator can comprise a spur gear or a bearing with a rotating motor. The actuator can be attached to the cylinder.

[0026] If the actuator is designed to pivot the first adjustment element, a shaft of the actuator can penetrate the second spring plate, for example through a through-hole in the second spring plate, wherein the shaft extends along the longitudinal axis between the cylinder and the second coil spring. The actuator can be designed to vary a torque to provide an adjustment and rotation angle of the first and / or second adjustment element, in particular due to a specific gear ratio. Optionally, the actuator can cooperate with adjustable dampers. The actuator has a weight of, for example, 0.5 kg or less. The actuator can comprise two or more actuators, wherein a first actuator can drive the first adjustment element and a second actuator can drive the second adjustment element.

[0027] According to a further embodiment of the invention, the cylinder has a groove, wherein the first spring plate engages in the groove such that the first spring plate is positively locked, wherein the first spring plate, in the unlocked state, is movable along a longitudinal axis of the cylinder at least by a predetermined path of movement. For example, the first spring plate can have a lug, in particular one, two or four lugs, for engaging in the groove. The cylinder can also have a plurality of grooves, for example two or four grooves, which are arranged around the cylinder, in particular arranged evenly around the cylinder. In addition, the second spring plate can have one, two or four lugs which engage in the groove or one of the plurality of grooves.As a result, movement of the first spring plate and / or the second spring plate is only possible along the longitudinal axis of the piston-cylinder arrangement due to the groove, and rotational movement of the first spring plate and / or the second spring plate is not possible. The groove extends over a distance such as the height of the at least one ramp of the second spring plate / adjusting element. For example, the groove extends from the first spring plate to a lower end of the cylinder. At the lower end of the cylinder, the groove can taper off / run out freely.

[0028] According to a further embodiment of the invention, the suspension system comprises exactly two different spring rates. The stiffness of the first coil spring is higher than the stiffness of the second coil spring, so that the suspension system operates effectively. Regardless of the relative stiffnesses of the first and second coil springs, the suspension system has a higher spring rate in the locked state than in the unlocked state. This allows the functionality of the described mechanism to be optimized.

[0029] According to a further embodiment of the invention, the suspension system further comprises a first ring element for axially fixing the first adjustment element, wherein the first ring element is fastened to the cylinder and is in contact with the first adjustment element on an opposite side of the first spring plate. Thus, an existing cylinder can be used as the basis for the piston-cylinder arrangement according to the invention. The existing cylinder can therefore be modified without a completely new design. For example, the first ring element is firmly connected to the cylinder, in particular welded. Alternatively, the existing cylinder can be enclosed in a housing or the like in which the grooves are provided.

[0030] Optionally, the suspension system further comprises a second ring element for axially fixing the second adjustment element, wherein the second ring element is attached to the cylinder and is in contact with the second adjustment element on an opposite side of the second spring plate. For example, the second ring element is firmly connected to the cylinder, in particular welded.

[0031] Optionally, the suspension system further comprises an auxiliary coil spring for supporting the first coil spring and preventing it from detaching from the piston in the locked state. The auxiliary coil spring may be arranged in series with the first and second coil springs, the auxiliary coil spring being attached between one end of the piston and the first coil spring. In particular, the auxiliary coil spring has a lower stiffness than the first coil spring and is only active when the load supported by the first coil spring is below a certain value. Furthermore, the auxiliary coil spring is only active when the load carried by the first and second coil springs in the unlocked state is below a certain value.

[0032] Optionally, the vehicle can have two or more axles. This allows the suspension system to be used on any axle of the vehicle.

[0033] According to a further embodiment of the invention, the axial locking step comprises pivoting a first adjustment element relative to the first spring plate. The first adjustment element can be pivoted relative to the first spring plate within a range of up to 180°, preferably within a range of approximately 15° to 90°, particularly preferably within a range of approximately 30° to 90°, in particular approximately 45°.

[0034] According to another embodiment of the invention, the method further comprises a step of axially moving a second spring plate toward the first spring plate, such that the second coil spring supported by the second spring plate is compressed and axially moves the first spring plate. For example, toward an upper end of a groove of the cylinder. The second spring plate can be moved axially toward the first spring plate by pivoting a second adjustment element configured to define an axial movement of the second spring plate relative to the cylinder.

[0035] Optionally, the method comprises a step of pivoting the second adjustment element back in a range of up to 180°, preferably in a range of approximately 15° to 90°, more preferably in a range of approximately 30° to 90°, in particular approximately 45°, relative to the second spring plate after the axial locking step. Thus, the second spring plate is moved axially away from the first spring plate by the second coil spring.

[0036] The invention is explained in more detail with reference to embodiments shown in the accompanying drawings. Short description of the drawings

[0037] The accompanying drawings provide a further understanding of the present invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present invention and together with the description serve to explain the principles of the invention. Other embodiments of the present invention and many of the intended advantages of the present invention will be readily appreciated as they become better understood by reference to the following detailed description. The elements in the drawings are not necessarily to scale with respect to one another. Throughout the figures, like reference numerals designate like or functionally similar components unless otherwise noted. Fig. 1 schematically shows a suspension system for varying a spring rate of the suspension system according to an embodiment of the invention. Fig. 2 schematically shows a suspension system for changing a spring rate of the suspension system according to another embodiment of the invention in a locked state. Fig. 3A, Fig. 3B schematically show a first adjustment element according to another embodiment of the invention. Fig. 4A, Fig. 4B schematically show a first spring plate according to another embodiment of the invention. Fig. 5A, Fig. 5B, Fig. 6A and Fig. 6B show schematically an interaction between the first spring plate of the Fig. 4A, Fig. 4B and the first adjustment element of the Fig. 3A, Fig. 3B during the axial locking of the first spring plate by pivoting the first adjusting element. Fig. 7A schematically shows a second adjustment element with ramps according to another embodiment of the invention. Fig. 7B schematically shows a second spring plate with ramps according to another embodiment of the invention. Fig. 8A, Fig. 8B show schematically an interaction between the second spring plate of Fig. 7B and the second adjustment element of Fig. 7A, when the second spring plate is moved axially by pivoting the second adjusting element. Fig. 9A, Fig. 9B show schematically the suspension system of Fig. 1 with the ramps of the Fig. 7A to 8B in an unlocked state ( Fig. 9A) compared to a locked state ( Fig. 9B). Fig. 10 shows a diagram of the spring rate of a suspension system according to another embodiment of the invention with an auxiliary coil spring. Fig. 11 schematically shows a vehicle according to another embodiment of the invention with two suspension systems. Fig. 12 shows a flowchart of a method for changing a spring rate of a suspension system according to another embodiment of the invention.

[0038] Although specific embodiments are shown and described herein, those skilled in the art will recognize that the specific embodiments shown and described may be replaced by a variety of alternative and / or equivalent embodiments without departing from the scope of the present invention. In general, this application is intended to cover any adaptations or variations of the specific embodiments described herein. Detailed description of the implementation examples

[0039] Fig. 1 schematically shows a suspension system 1 for changing a spring rate of the suspension system 1.

[0040] The suspension system 1 comprises a piston-cylinder arrangement with a piston 2 movable in a cylinder 3, a first coil spring 4 and a second coil spring 5. The first coil spring 4 and the second coil spring 5 are arranged in series along the piston-cylinder arrangement.

[0041] Furthermore, the suspension system 1 comprises an axially movable first spring plate 6, which has a first side 6a and a second side 6b. The first side 6a supports the first coil spring 4. Thus, the first coil spring 4 is arranged between one end of the piston 2 and the first spring plate 6. The first spring plate 6 rests, for example, on the cylinder 3. The second side 6b supports the second coil spring 5. That is, the first coil spring 4 and the second coil spring 5 are separated from each other by the first spring plate 6. Fig. 1, the first side 6a is a top side and the second side 6b is a bottom side of the first spring plate 6.

[0042] Furthermore, the suspension system 1 comprises a first adjusting element 7 which is designed to axially block the first spring plate 6 relative to the cylinder 3 in a locked state. This means that in the locked state only the first coil spring 4 is active. Therefore, the spring rate of the suspension system 1 in the locked state substantially corresponds to the stiffness of the first coil spring 4. The locked state can be used, for example, as a sport state to increase body control. In contrast to the locked state, an unlocked state can be used as a comfort state to reduce body accelerations. In the unlocked state, the first coil spring 4 and the second coil spring 5 are active. Therefore, the spring rate of the suspension system 1 is a combination of the stiffness of the first coil spring 4 and a stiffness of the second coil spring 5 in the unlocked state.Therefore, in the unlocked state, the first spring plate 6 can move axially along a longitudinal axis X of the piston-cylinder assembly. The first spring plate 6 can move to a position in which a force acting on the first side 6a and a force acting on the second side 6b are balanced.

[0043] The first adjustment element 7 is arranged on the second side 6b of the first spring plate 6 and is designed such that, in the unlocked state, it limits an axial movement of the first spring plate 6 relative to the cylinder 3 to one side, in this case corresponding to a downward movement. As a result, in the unlocked state, the first spring plate 6 does not come into contact with the first adjustment element 7 in the axial direction over the entire spring travel.

[0044] The suspension system 1 further comprises an axially movable second spring plate 8 which supports the second coil spring 5.

[0045] In addition, the suspension system 1 comprises a second adjustment element 9, which is designed to define an axial movement of the second spring plate 8 relative to the cylinder 3. For example, the first and second adjustment elements 7, 9 are designed as an adjustment plate.

[0046] In Fig. 2 schematically shows a suspension system 1 for electromechanically changing a spring rate of the suspension system 1. The suspension system 1 of the Fig. 2 essentially corresponds to the suspension system of the Fig. 1.

[0047] The suspension system 1 of the Fig. 2 further comprises two actuators 13-1, 13-2 for pivoting both the first and the second adjustment element 7, 9, wherein a first actuator 13-1 could drive the first adjustment element 7 and a second actuator 13-2 could drive the second adjustment element. The two actuators 13-1, 13-2 are designed, for example, as stepper motors. Furthermore, the two actuators 13-1, 13-2 comprise a spur gear. The two actuators 13-1, 13-2 can be fastened to the cylinder 3. The first actuator 13-1 is designed to pivot the first adjustment element 7, wherein a shaft of the first actuator 13-1 can penetrate the second spring plate 8, for example, through a through-bore 18 in the second spring plate 8. The shaft extends along the longitudinal axis X between the cylinder 3 and the second coil spring 5. Each actuator can be designed to provide a torque for adjustment and angle of rotation of the first and second coil springs.second adjustment element is varied based on a specific gear ratio. The first adjustment element 7 and the second adjustment element 9 each comprise a gear 12, so that the first and second adjustment elements 7, 9 can be pivoted by the two actuators 13-1, 13-2 by means of the gear 12.

[0048] The first and second adjustment elements 7, 9 are pivotable about the longitudinal axis X of the first and second spring plates 6, 8, respectively. For example, both the first and second adjustment elements are pivotable within a range of approximately 15° to 90° relative to the first and second spring plates 6, 8, respectively.

[0049] In this example, the first spring plate 6 is axially locked in the locked position by pivoting the first adjusting element 7 relative to the first spring plate 6.

[0050] Furthermore, the suspension system 1 comprises a first ring element 15 for axially fixing the first adjustment element 7, wherein the first ring element 15 is attached to the cylinder 3 and is in contact with the first adjustment element 7 on an opposite side of the first spring plate 6. For example, the first ring element 15 is welded to the cylinder. The first adjustment element 7 sits on the first ring element 15, wherein the first adjustment element 7 is pivotable relative to the first ring element 15.

[0051] Furthermore, the suspension system 1 comprises a second ring element 16 for axially fixing the second adjustment element 9, wherein the second ring element 16 is attached to the cylinder 3 on a side opposite the second spring plate 8 and is in contact with the second adjustment element 9. The second ring element 16 is designed, for example, like the first ring element 15 and is attached to the cylinder 3.

[0052] The suspension system 1 of Fig. 2 comprises exactly two different spring rates. The stiffness of the first coil spring 4 is higher than the stiffness of the second coil spring 5, so that the suspension system 1 operates effectively. Regardless of the relative stiffnesses of the first coil spring 4 and the second coil spring 5, the suspension system 1 offers a higher spring rate in the locked state.

[0053] The Fig. 3A and Fig. 3B schematically show a first adjustment element 7. Specifically, the first adjustment element 7 is shown in a perspective view ( Fig. 3A), in a plan view and in a sectional view AA ( Fig. 3B).

[0054] The exemplary first adjustment element 7 is designed here as an adjustment plate. The first adjustment plate 7 comprises a tubular base body, four plate sections 18, and a toothing 12. The four plate sections 18 are arranged at an upper end of the first adjustment plate 7. The toothing 12 is arranged at a lower end of the first adjustment plate 7. The first adjustment plate 7 is pivotable by means of the serration 12.

[0055] The Fig. 4A and Fig. 4B schematically show a first spring plate 6. In particular, the first spring plate 6 is shown in a perspective view ( Fig. 4A) and in a top view ( Fig. 4B).

[0056] The exemplary first spring plate 6 is circular and has a recess 19 that is essentially cross-shaped. In other words, the first spring plate 6 has a circular recess for the cylinder, wherein the recess 19 extends in four directions from the center of the circular recess. In particular, the recess 19 of the first spring plate 6 corresponds to four plate sections of the first adjustment plate 7, as shown in Fig. 3A, so that the four plate sections 18 can engage in the recess 19.

[0057] In addition, the first spring plate 6 has four lugs 17 that protrude into a groove in the cylinder. The four lugs 17 face, for example, the center of the recess 19.

[0058] The Fig. 5A, Fig. 5B, Fig. 6A and Fig. 6B show schematically the interaction of the first spring plate 6 of the Fig. 4A, Fig. 4B and the first adjustment element 7 of the Fig. 3A, Fig. 3B during the axial locking of the first spring plate 6 by pivoting the first adjusting element 7. In particular, the Fig. 5A, Fig. 6A the first spring plate 6 mounted on a cylinder 3 in an unlocked state in a perspective view ( Fig. 6A), in a plan view and in a sectional view AA ( Fig. 5A), where the Fig. 5B, Fig. 6B the first spring plate 7 mounted on the cylinder 3 in a locked state in a perspective view ( Fig. 6B) and in a sectional view BB ( Fig. 5B).

[0059] The cylinder 3 has four grooves 14, wherein the first spring plate 6 engages in the grooves 14, so that the first spring plate 6 is positively locked. The four grooves are arranged around the cylinder 3, in particular evenly arranged around the cylinder. For example, the four grooves 14 extend from the first spring plate 6 to a lower end of the cylinder 3, as shown in particular in Fig. 5B. The four grooves 14 can terminate or terminate freely at the lower end of the cylinder 3. In the unlocked state, the first spring plate 6 is movable along a longitudinal axis X of the cylinder 3 by at least a predetermined travel distance 1. This means that in the unlocked state, there is no contact between the first spring plate 6 and the first adjusting plate 7 in the axial direction. In particular, the four lugs 17 of the first spring plate 6 can engage in the four grooves 14. This has the consequence that, due to the grooves, movement of the first spring plate 6 is only possible along the longitudinal axis of the piston-cylinder arrangement, and rotational movement of the first spring plate 6 is not possible.

[0060] Fig. 7A schematically shows a second adjustment element 9 with ramps 11. The second adjustment element 9 is shown in particular in a plan view and in a sectional view AA.

[0061] The exemplary second adjustment element 9 is designed here as an adjustment plate. The first adjustment plate 9 comprises a tubular base body, a circumferential plate section, and a toothing 12. The circumferential plate section is arranged at an upper end of the second adjustment plate 9. The serration 12 is arranged at a lower end of the second adjustment plate 9. The second adjustment plate 9 is pivotable with the serration 12.

[0062] In particular, the second adjustment plate 9 comprises four ramps 11. The four ramps 11 are arranged on the circumferential plate section, in particular arranged uniformly around the circumferential plate section.

[0063] Fig. 7B schematically shows a second spring plate 8 with ramps 10. The second spring plate 8 is shown in particular in a view from below and in a sectional view BB.

[0064] The exemplary second spring plate 8 is circular and has a circular recess for the cylinder. Furthermore, the second spring plate 8 has four ramps 10. The four ramps 10 are arranged on the circular second spring plate 8, in particular evenly arranged around the circular second spring plate 8. The four ramps 10 of the circular second spring plate 8 essentially correspond to the four ramps 11 of the second adjustment plate 9 of Fig. 7A, so that the ramps 11 of the second adjustment plate 9 and the ramps 10 of the second spring plate 8 can be brought into engagement with one another.

[0065] In addition, the second spring plate 8 has two lugs 17 that protrude into a groove in the cylinder. The two lugs 17 face, for example, the center of the circular recess.

[0066] The Fig. 8A and Fig. 8B show schematically the interaction of the second spring plate 8 from Fig. 7B and the second adjusting element 9 from Fig. 7A during axial displacement of the second spring plate 8 by pivoting the second adjusting element 9. In particular Fig. Figure 8A shows the second spring plate 8 in a lower position in a view from below and in a sectional view AA, where Fig. 8B shows the second spring plate 8 in an upper position in a view from below and in a sectional view BB.

[0067] In the lower views of the Fig. 8A and Fig. 8B schematically shows a position of the four ramps 10 of the second spring plate 8 in relation to the four ramps 11 of the second adjustment plate 9.

[0068] The second adjustment plate 9 can be pivoted, for example, by 45° relative to the second spring plate 8. The second adjustment plate 9 can be pivoted by 45° in both directions. By pivoting the second adjustment element / second adjustment plate 9, the second spring plate 8 is displaced axially toward the first spring plate, since the four ramps 11 of the second adjustment plate 9 and the four ramps 10 of the second spring plate 8 slide relative to one another.

[0069] The pitch of the ramps 10, 11 depends on the stiffness of the first and second coil springs. The height of the ramps 10, 11 depends on the required displacement h of the first spring plate in the direction of the longitudinal axis in order to achieve a locked position of the first spring plate or the locked state. In other words, the size and shape of the ramps 10, 11 must be defined according to the required spring travel and the coil spring stiffness used. The axial movement of the second spring plate 8 generates an impact on the second coil spring 5 and therefore also moves the first spring plate 6. When the first spring plate is blocked by the first adjustment plate 7, the second adjustment plate 9 is pivoted back and the second spring plate 8 moves away from the first spring plate 6.

[0070] The Fig. 9A and Fig. 9B show schematically the suspension system of Fig. 1 with the ramps 10, 11 of the Fig. 7A to 8B in an unlocked state ( Fig. 9A) compared to a locked state ( Fig. 9B).

[0071] In Fig. 9A, the upper end of the first adjustment element 7 is at the same height as the first spring plate 6. Therefore, the first adjustment element 7 and the first spring plate 6 can be moved axially relative to each other. The second spring plate 8 is in its lower position, in which the ramps 10, 11 of the second spring plate 8 and the second adjustment element 9 engage with each other.

[0072] In Fig. 9B, the upper end of the first adjustment element 7 is lifted by the second coil spring 5. Therefore, the first spring plate 6 is axially blocked between the second adjustment element 7 and an upper end of the groove of the cylinder 3. The second spring plate 8 is in its upper position, in which the ramps 10, 11 of the second spring plate 8 and the second adjustment element 9 lie one above the other to lift the second spring plate 8 by a displacement h. An axial movement of the second spring plate 8 towards the first spring plate 6 also causes an axial movement of the first spring plate 6 in the same direction. In particular, the displacement h is large enough to press the first spring plate 6 to the upper end of the groove in the cylinder 3.

[0073] Fig. Figure 10 shows a spring rate diagram of a suspension system according to another embodiment of the invention with an auxiliary coil spring. In particular, the diagram shows the spring rate of the suspension system in a locked state compared to an unlocked state.

[0074] The suspension system used to draw the diagram essentially includes the Fig. 2, wherein the suspension system further comprises the auxiliary coil spring to support the first coil spring and prevent its detachment from the piston in the locked state. The auxiliary coil spring may be arranged in series with the first and second coil springs, with the auxiliary coil spring being secured between one end of the piston and the first coil spring. In particular, the auxiliary coil spring has a lower stiffness than the first coil spring and is only active when the load supported by the first coil spring is below a certain value.

[0075] The diagram illustrates a force in N in relation to a displacement in mm. A spring rate LM in the locked state is stiffer than a spring rate UM in the unlocked state of the suspension system. Therefore, the spring rate LM is steeper than the spring rate UM. The spring rate LM and the spring rate UM are, for example, linear. The spring rate LM essentially corresponds to a stiffness of the first coil spring. A spring rate HS essentially corresponds to a stiffness of the auxiliary coil spring. The spring rate UM is a combination of the stiffnesses of the first coil spring, the second coil spring, and the auxiliary coil spring.

[0076] In Fig. 11 schematically shows a vehicle 100 with two suspension systems 1.

[0077] The two suspension systems 1 can be used on a front axle or a rear axle. Alternatively, the vehicle can also comprise four suspension systems 1.

[0078] Optionally, the vehicle may include two or more axles. Thus, the suspension system 1 can be used on any axle of the vehicle.

[0079] Fig. 12 shows a flowchart of a method M for changing a spring rate of a suspension system. Specifically, a method M for changing a spring rate of a suspension system 1 is described in accordance with Fig. 1, Fig. 2, Fig. 3A, Fig. 3B, Fig. 4A, Fig. 4B, Fig. 5A, Fig. 5B, Fig. 6A, Fig. 6B, Fig. 7A, Fig. 7B, Fig. 8A, Fig. 8B, Fig. 9A or Fig. 9B.

[0080] Method M includes the steps axial movement M1, axial locking M2 and swinging back M3.

[0081] In the axial movement step M1, a second spring plate 8 is moved axially toward a first spring plate 6, so that a second coil spring 5 supported by the second spring plate 8 is compressed and moves the first spring plate 6 axially toward an upper end of a groove 14 of a cylinder 3. The second spring plate 8 can be moved axially toward the first spring plate 6 by pivoting a second adjusting element 9, which is configured to limit axial movement of the second spring plate 8 relative to the cylinder 3. The second adjusting element 9 can be pivoted by 45° relative to the second spring plate 8.

[0082] In the axial locking step M2, the axially movable first spring plate 6 is axially locked relative to the cylinder 3 in a locked state, wherein the first spring plate 6 has a first side 6a and a second side 6b, wherein the first side 6a supports a first coil spring 4 and the second side 6b supports the second coil spring 5. The axial locking M2 comprises pivoting a first adjusting element 7 relative to the first spring plate 6. The first adjusting element 7 can be pivoted by 45° relative to the first spring plate 6. After step M2, a locked state exists.

[0083] The described method M can also be applied in reverse to bring the suspension system 1 from the locked state into an unlocked state. In particular, the axially locked first spring plate 6 would be axially unlocked relative to the cylinder 3. The axial unlocking can comprise pivoting a first adjusting element 7 relative to the first spring plate 6. The first adjusting element 7 can be pivoted by 45° relative to the first spring plate 6. Once the first spring plate 6 is axially unlocked, the unlocked state is present. This means that steps M1 and M3 are not required for unlocking.

[0084] In the optional pivoting-back step M3, the second adjusting element 9 can be pivoted back by approximately 45° relative to the second spring plate 8 after the axial locking step M2. As a result, the second spring plate 8 is moved axially away from the first spring plate 6 by the second coil spring 5.

[0085] In the foregoing detailed description, various features are summarized in one or more examples to facilitate disclosure. It is to be understood that the above description is illustrative and not restrictive. It is intended to cover all alternatives, modifications, and equivalents of the various features and embodiments. Many other examples will become apparent to those skilled in the art upon review of the above description. The embodiments were chosen and described in order to explain the principles of the invention and their practical applications, and to thereby enable others skilled in the art to utilize the invention and various embodiments with various modifications as are suited to the particular application. Reference list 1 suspension system 2 pistons 3 cylinders 4 first coil spring 5 second coil spring 6 first spring plate 7 first adjustment element 8 second spring plate 9 second adjustment element 10 Ramp of the second spring plate 11 Ramp of the second adjustment element 12 gear 13-1 first actuator 13-2 second actuator 14 grooves 15 first ring element 16 second ring element 17 Nose 18 plate section 19 Recess 100 vehicles X Longitudinal axis h shift 1 movement path M procedure M1 axial movement M2 axial locking QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] EP 3 400 142 A1

[0005] US 2011 / 0291338 A1

[0005]

Claims

[1] Suspension system (1) for changing a spring rate of the suspension system, in particular for electromechanically changing the spring rate of the suspension system, comprising: a piston-cylinder arrangement with at least one piston (2) which is movable in a cylinder (3); a first coil spring (4) and a second coil spring (5) arranged in series along the piston-cylinder arrangement; an axially movable first spring plate (6) having a first side (6a) and a second side (6b), wherein the first side (6a) supports the first coil spring (4) and the second side (6b) supports the second coil spring (5); and a first adjusting element (7) which is designed to axially lock the first spring plate (6) relative to the cylinder (3) in a locked state. [2] Suspension system (1) according to claim 1, wherein the first adjusting element (7) is arranged on the second side (6b) of the first spring plate (6) and is designed to limit an axial movement of the first spring plate (6) relative to the cylinder (3) to one side in an unlocked state. [3] Suspension system (1) according to claim 1 or 2, further comprising an axially movable second spring plate (8) supporting the second coil spring (5), and a second adjusting element (9) configured to define an axial movement of the second spring plate (8) relative to the cylinder (3). [4] Suspension system (1) according to claim 3, wherein the second adjustment element (9) has at least one ramp (11) which projects in the direction of the second spring plate (8), and wherein the second spring plate (8) has at least one ramp (10) which projects in the direction of the second adjustment element (9) and corresponds thereto, so that the at least one ramp (10, 11) of the second adjustment element (9) and the second spring plate (8) can be brought into engagement with one another. [5] Suspension system (1) according to one of claims 1 to 4, wherein at least one of the two adjusting elements (7, 9) is pivotable about a longitudinal axis (X) of the first or second spring plate (6, 8) and relative thereto. [6] Suspension system (1) according to claim 5, wherein the first spring plate (6) is axially locked in the locked state by pivoting the first adjusting element (7) relative to the first spring plate (6). [7] Suspension system (1) according to one of claims 1 to 6, wherein at least one of the two adjusting elements (7, 9) has a gear (12), in particular a serrated gear, by means of which the first and / or the second adjusting element (7, 9) can be pivoted. [8] Suspension system (1) according to one of claims 1 to 7, further comprising an actuator (13-1; 13-2) for pivoting at least one of the two adjusting elements (7, 9). [9] Suspension system (1) according to one of claims 1 to 8, wherein the cylinder (3) has a groove (14), wherein the first spring plate (6) engages in the groove (14) such that the first spring plate (6) is positively locked, wherein the first spring plate (6) is movable along a longitudinal axis (X) of the cylinder (3) at least with a predetermined movement path in the unlocked state. [10] Suspension system (1) according to one of claims 1 to 9, wherein the suspension system (1) has exactly two different spring rates. [11] Suspension system (1) according to one of claims 1 to 10, further comprising a first ring element (15) for axially fixing the first adjusting element (7), wherein the first ring element (15) is fixed to the cylinder (3) and is in contact with the first adjusting element (7) on an opposite side of the first spring plate (6). [12] Vehicle (100), in particular a motor vehicle, with a suspension system (1) according to one of claims 1 to 11. [13] Method (M) for changing a spring rate of a suspension system, in particular a suspension system (1) according to one of claims 1 to 11, wherein the method (M) comprises: axially locking (M2) an axially movable first spring plate (6) relative to a cylinder (3) in a locked state, wherein the first spring plate (6) has a first side (6a) and a second side (6b), wherein the first side (6a) supports a first coil spring (4) and the second side (6b) supports a second coil spring (5). [14] Method (M) according to claim 13, wherein the axial locking (M2) comprises pivoting a first adjusting element (7) relative to the first spring plate (6). [15] Method (M) according to claim 13 or 14, further comprising: axially moving (M1) a second spring plate (8) in the direction of the first spring plate (6) so that the second coil spring (5) supported by the second spring plate (8) is compressed and moves the first spring plate (6) axially.

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