Multi-section progressive increase type variable stiffness spring for automobile suspension and working method of multi-section progressive increase type variable stiffness spring

Abstract

The invention discloses a multi-section progressive increase type variable stiffness spring for an automobile suspension and a working method thereof.The multi-section progressive increase type variable stiffness spring comprises a piston, an air bag and an upper cover plate which are sequentially connected from bottom to top, one end of an air pipe is connected with the air bag, and the other end of the air pipe is connected with an additional air chamber; a second spring is sleeved inside the air bag and outside the dowel bar, one end of the second spring is a fixed end, and the other end of the second spring is a free end; a third spring is sleeved outside the dowel bar between the piston top plate and the dowel plate in the piston, one end of the third spring is a fixed end, the other end of the third spring is a free end, the pressure in the air bag is reduced when large rigidity is provided, and the second spring and the third spring respectively select a spiral spring, a wave spring, a rubber spring and a buffer block with the same or different parameters. And the multi-section suspension rigidity such as three-section two, three-section three, four-section four, five-section three, five-section five and the like is obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of automobiles and relates to an automobile suspension structure, in particular to a variable stiffness spring used for an automobile suspension. Background Art

[0002] The suspension is an important structural and functional component of the automobile. It mainly attenuates the vibration transmitted from the wheels to the car body when the car is driving on a bad road, so that the passengers can enjoy good riding comfort. In order to obtain the best low-frequency and high-frequency vibration suppression effect of the car body, the suspension provided in the document with patent application number CN2024112169851 and name "Gradually increasing stiffness type three-mass two-level vibration reduction graded control suspension and design and application" uses a gradually increasing stiffness spring, which is installed between the car body and the wheel after being connected in parallel with the adjustable damping shock absorber. The upper ends are connected to the car body, and the lower ends are fixedly connected to the wheels below through the first connecting device; the gradually increasing stiffness spring has a stroke-type stiffness control valve, which includes a valve core and a valve body. The valve body is fixedly connected to the upper cover plate through a valve body mounting seat. The valve core passes through the central through hole of the valve body and is exposed at both the upper and lower ends. The upper cover plate, the airbag, the piston, and the second connecting device are connected in sequence from top to bottom, and one end of the intake pipe is connected to the airbag. The exhaust manifold has two upper and lower air pipes, one end of which is connected to the valve body and is respectively connected to the upper and lower annular valve core grooves on the outer wall of the valve core. The upper and lower air pipes are connected to the valve body and are connected to the stiffness control air chamber through the electromagnetic valve after being merged into one outside the valve body. The upper and lower ends of the valve core are fixed with baffles, and the axial distances of the two baffles from the cross section in the middle of the valve core step are equal; when the vehicle body is at a medium height and there is no relative movement between the valve body and the valve core in the initial state, a valve body groove faces the two annular valve core grooves and is connected to both the upper and lower exhaust pipes; when the vehicle body moves up and down relative to the wheel, the valve core provides less stiffness when the two air pipes are not closed, and provides greater stiffness when the two air pipes are closed. When the car is driving on a bumpy road, the adjustable damping shock absorber outputs a small damping, and is coordinated with the wheel dynamic vibration absorber, so that the dynamic stroke of the gradually increasing stiffness spring is small, and therefore its stiffness is small, which greatly improves the vibration isolation rate of the parallel structure composed of the gradually increasing stiffness spring and the adjustable damping shock absorber. After the wheel dynamic vibration absorber absorbs the vibration near the natural frequency of the wheel, the vibration acceleration transmitted to the car body by the parallel structure composed of the gradually increasing stiffness spring and the adjustable damping shock absorber is greatly reduced, thereby achieving a significant improvement. Improve the high-frequency vibration suppression performance of the car body; when the car is running on a long-wave undulating road surface, the adjustable damping shock absorber outputs large damping, which makes the dynamic stroke of the gradually increasing stiffness spring smaller, so its stiffness is smaller, and the body vibration offset frequency of the suspension is much smaller than the body vibration offset frequency of the air suspension using a traditional single-chamber air spring. Therefore, the transmission ratio of the wheel displacement to the body displacement changes from greater than 1 to less than 1, and then the vibration acceleration of the car body at the body vibration offset frequency is greatly reduced, thereby greatly improving the low-frequency vibration suppression performance of the car body.

[0003] However, the problems with the suspension provided in the document are: (1) the stiffness of the suspension is determined by the working volume of the airbag. The smaller the volume of the airbag, the greater the working pressure inside it. Compared with the traditional air spring, when providing high stiffness, the airbag is subjected to greater pressure, so the safety of the airbag is affected to a certain extent; (2) the suspension can only provide two stiffness changes, which restricts further improvement of the comprehensive performance of the suspension; (3) the upper cover plate and the piston of the gradually increasing stiffness spring used in the suspension can only transmit a large axial force. When the suspension is subjected to lateral force, rotational torque and rolling torque, the upper cover plate and the piston will produce lateral, rotational and rolling movements, which will affect the safety of the airbag on the one hand and the performance and safety of the air spring on the other. Summary of the invention

[0004] The purpose of the present invention is to solve the above-mentioned problems existing in the progressively increasing stiffness spring used in the above-mentioned existing suspension, and to provide a multi-stage progressively increasing variable stiffness spring for automobile suspension and a working method thereof, so as to improve the safety of the airbag and further improve the comprehensive performance of the three-mass two-stage vibration reduction graded control suspension, and provide multi-stage suspension stiffness.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the multi-stage progressive variable stiffness spring for automobile suspension of the present invention is: it includes a piston, an air bag and an upper cover plate connected in sequence from bottom to top, the upper cover plate is connected to the vehicle body or frame upward, the top of the piston is a piston top plate fixedly connected to the lower end of the air bag, the bottom of the piston is a piston bottom plate connected downwardly to the axle or wheel, one end of the air pipe is connected to the air bag, and the other end is connected to the additional air chamber, the air pipe is provided with a solenoid valve, the interior of the piston is a hollow chamber, the chamber is provided with a force transmission plate that can move up and down, the lower end of the force transmission rod is fixedly connected to the middle of the force transmission plate, and passes through the piston top plate and the air bag in sequence upward and is fixedly connected to the upper cover plate, inside the air bag, a second spring is sleeved on the outside of the force transmission rod, and the lower end of the second spring is fixedly connected On the upper end surface of the piston top plate, the upper end of the second spring is a free end, or the lower end surface of the second spring is set as a free end, and the upper end surface is fixedly connected to the lower end surface of the upper cover plate; in the initial state, the free end of the second spring does not contact the lower end surface of the upper cover plate or the upper end surface of the piston top plate, and a preset distance of a ride comfort improvement stroke threshold is left between them; a third spring is provided inside the piston, the upper end of the third spring is fixedly connected to the lower end surface of the piston top plate, the lower end of the third spring is a free end, or the upper end surface of the third spring is set as a free end, and the lower end surface is fixedly connected to the upper end surface of the force transmission plate, and in the initial state, the free end of the third spring does not contact the upper end surface of the force transmission plate or the lower end surface of the piston top plate, and a preset distance of a ride comfort improvement stroke threshold is left between them.

[0006] Preferably, a regular polygonal through hole is opened on the piston top plate, the cross section of the force transmission rod is a regular polygon, and a regular polygonal first guide is arranged on the regular polygonal through hole of the piston top plate to cooperate with the force transmission rod; a circular annular second guide is provided on the outer circumferential surface of the force transmission plate to cooperate with the inner surface of the piston cylinder.

[0007] Preferably, the second spring and the third spring are respectively coil springs, wave springs, rubber springs, metal rubber shock absorbers, buffer blocks or wire rope shock absorbers with the same or different parameters.

[0008] The technical solution adopted by the working method of a multi-stage progressive variable stiffness spring for automobile suspension of the present invention is:

[0009] When the car is driving on a bumpy or long-wave undulating road, the solenoid valve is turned on, the upward stroke of the upper cover relative to the piston exceeds the preset ride comfort improvement stroke threshold, the force transmission plate moves upward to contact and compress the third spring, so that a force is generated between the force transmission plate and the piston top plate and transmitted to the upper cover through the force transmission rod, and the air spring composed of the airbag, the upper cover and the piston works in parallel with the third spring;

[0010] When the downward stroke of the upper cover plate relative to the piston exceeds a preset ride comfort improvement stroke threshold, the upper cover plate moves downward, contacts and compresses the second spring, so that a force is generated between the upper cover plate and the piston top plate, and the air spring and the second spring work in parallel;

[0011] When the car is traveling at high speed on a good road, the control solenoid valve is closed, and the second spring or the third spring is connected in parallel with the air spring to provide greater stiffness according to the smaller air chamber volume, and together they provide stiffness.

[0012] Furthermore, when the second and third springs use the same stiffness k1 spring, in the riding comfort improvement area [-f d1 , f d1 ], the air spring works according to the larger air chamber volume to provide a smaller stiffness k0; in the lower body posture stability area [-f d2 , -f d1 ), the smaller stiffness k0 is connected in parallel with the stiffness k1 provided by the second spring to form a stiffness k0+k1; in the upper body posture stable area (f d1 , f d2 ], the smaller stiffness k0 is connected in parallel with the stiffness k1 provided by the third spring to form a stiffness k0+k1; f d1 is the travel threshold for ride comfort improvement, f d2 It is the upper and lower body posture stability area (f d1 , f d2 ]、[-f d2 , -f d1 ) of the suspension limit travel.

[0013] Furthermore, when the second and third springs are springs with different stiffnesses k1 and k2, respectively, in the riding comfort improvement area [-f d1 , f d1 ] The air spring provides a small stiffness k0, in the lower body posture stability area [-f d2 , -f d1 ) The smaller stiffness k0 provided by the air spring is connected in parallel with the stiffness k1 provided by the second spring to form a stiffness k0+k1; in the upper body posture stability area (f d1 , f d2 The smaller stiffness k0 provided by the air spring is connected in parallel with the stiffness k2 provided by the third spring to form a stiffness k0+k2; f d1 is the travel threshold for ride comfort improvement, f d2 It is the upper and lower body posture stability area (f d1 , f d2 ]、[-f d2 , -f d1 ) of the suspension limit travel.

[0014] Furthermore, when the second spring adopts a wave spring with two-stage stiffness characteristics, the larger deformation section when it starts to compress is [f d1 , s1] range, is a section with smaller stiffness k3, and the smaller deformation section of the compression end section is in (s1, f d2 ] range, which is the section with larger stiffness k4, f d1 <s1<f d2 , s1 is determined by the second spring characteristics; the third spring adopts a wave spring with two-stage stiffness characteristics, and the larger deformation section when it starts to compress is [f d1 , s2] range, is a section with smaller stiffness k5, and the smaller deformation section of the compression end section is in (s2, f d2 ] range, which is the section with larger stiffness k6, f d1 <s2<f d2 , s2 is determined by the characteristics of the third spring wave spring, and when the second and third springs are matched with the air spring, multiple stages of multiple increasing stiffness characteristics are obtained.

[0015] After adopting the above technical solution, the present invention has the following beneficial effects compared with the suspension disclosed in the document with patent application number CN2024112169851:

[0016] 1. The present invention arranges a spring on the upper and lower end surfaces of the piston top plate respectively, providing high stiffness in the compression and tension vehicle body posture stabilization stroke area, reducing the pressure in the airbag when providing high stiffness, and improving the safety of the first spring (i.e., air spring) composed of the airbag, the upper cover plate and the piston.

[0017] 2. The second spring and the third spring in the present invention are respectively selected from coil springs, wave springs, rubber springs, metal rubber shock absorbers, buffer blocks or wire rope shock absorbers with the same or different parameters, so that multiple sections of increasing stiffness such as three sections of two, three sections of three, four sections of four, five sections of three, and five sections of five can be obtained, providing more suspension stiffness options for further improving the overall performance of the suspension.

[0018] 3. The present invention adopts a regular polygonal force transmission rod in cooperation with a regular polygonal first guide on the piston top plate to withstand the torsional moment between the upper cover plate and the piston and reduce the torsional deformation of the airbag. The second guide on the outer periphery of the force transmission plate cooperates with the inner circumference of the piston cylinder to withstand the lateral force and rolling moment between the upper cover plate and the piston, reduce the lateral and rolling deformation of the airbag, improve the safety of the airbag, and provide a guarantee for the normal performance of the air spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural schematic diagram of a multi-stage progressive variable stiffness spring for automobile suspension of the present invention;

[0020] Figure 2 yes Figure 1 An enlarged top view of the matching structure of the force transmission rod and the piston top plate;

[0021] Figure 3 It is a working principle diagram of the multi-stage progressively variable stiffness formed when the second spring and the third spring are used in the present invention.

[0022] In the figure: 1. upper cover plate; 2. second spring; 3. air bag; 4. first guide; 5. third spring; 6. second guide; 7. piston; 7-1. piston bottom plate; 7-2. piston top plate; 8. force transmission plate; 9. force transmission rod; 10. additional air chamber; 11. solenoid valve; 12. air pipe. DETAILED DESCRIPTION

[0023] See also Figure 1 and Figure 2 The multi-stage progressive variable stiffness spring for automobile suspension of the present invention is a composite structure of air spring, comprising a piston 7, an air bag 3 and an upper cover plate 1 connected in sequence from bottom to top, the upper cover plate 1 is connected upwardly to a vehicle body or a frame (the vehicle body or the frame is omitted in the figure), the lower end of the upper cover plate 1 is fixed to the upper end of the air bag 3, and the lower end of the air bag 3 is fixedly connected to the piston 7. Among them, the top of the piston 7 is a piston top plate 7-2, which is fixedly connected to the lower end of the air bag 3, and the bottom of the piston 7 is a piston bottom plate 7-1, and the piston bottom plate 7-1 is connected downwardly to an axle or a wheel (the axle or the wheel is omitted in the figure).

[0024] One end of the air pipe 12 is connected to the airbag 3, and the other end is connected to the additional air chamber 10. A solenoid valve 11 is installed on the air pipe 12 to control the communication between the additional air chamber 10 and the airbag 3. The additional air chamber 10 is also connected to an external air supply and exhaust unit, and the additional air chamber 10 can replenish or exhaust gas.

[0025] See also Figure 1 and Figure 3 The piston 7 has a hollow chamber inside, and a force transmission plate 8 is arranged inside the chamber. The force transmission plate 8 is circular and can move up and down in the chamber inside the piston 7. The lower end of the force transmission rod 9 is fixedly connected to the center of the force transmission plate 8, and passes through the piston top plate 7-2 and the airbag 3 on the top of the piston 7 upwards and is fixedly connected to the upper cover plate 1. The force transmission rod 9 and the upper cover plate 1 can move up and down relative to the piston 7. The outer diameter of the force transmission rod 9 is smaller than the outer diameter of the force transmission plate 8. Inside the airbag 3, a second spring 2 is coaxially sleeved outside the force transmission rod 9. The second spring 2 is arranged up and down, and one end of the second spring 2 can be a fixed end and the other end is a free end. When the lower end of the second spring 2 is fixedly connected to the upper end surface of the piston top plate 7-2, the upper end of the second spring 2 is a free end, and the equilibrium position state when the car is not driving is taken as the initial state. In the initial state, the upper end of the second spring 2 does not contact the lower end surface of the upper cover plate 1, and a pre-set ride comfort improvement stroke threshold f is left between them. d1 This distance, Figure 3 Suspension travel f in the lower middle section for improved ride comfort d1 When the lower end surface of the second spring 2 is set as a free end, the lower end surface of the second spring 2 is suspended in the air, and the upper end surface is fixedly installed on the lower end surface of the upper cover plate 1. In the initial state, the free end of the second spring 2 does not contact the upper end surface of the piston top plate 7-2, and a preset ride comfort improvement stroke threshold f is left between them. d1 The distance does not affect the performance of the multi-stage progressive variable stiffness spring of the present invention.

[0026] In the present invention, a third spring 5 is sleeved on the outside of the force transmission rod 9 between the piston top plate 7-2 and the force transmission plate 8 inside the piston 7. The third spring 5 is also arranged up and down, one end of which can be a fixed end and the other end is a free end.

[0027] When the upper end surface of the third spring 5 is fixedly connected to the lower end surface of the piston top plate 7-2 at the top of the piston 7, the lower end of the third spring 5 is a free end. When the vehicle is in a balanced position without driving, the lower end of the third spring 5 does not contact the upper end surface of the force transmission plate 8, and a preset ride comfort improvement stroke threshold value f is left between them. d1 This distance, Figure 3 Suspension travel f in the middle and upper riding comfort improvement zone d1The outer diameter of the third spring 5 is smaller than the inner diameter of the piston 7. When the upper end surface of the third spring 5 is set as a suspended free end, and the lower end surface is fixedly mounted on the upper end surface of the force transmission plate 8, the free end of the third spring 5 does not contact the lower end surface of the piston top plate 7-2, and a preset upper ride comfort improvement stroke threshold f is left between them. d1 The distance does not affect the performance of the multi-stage progressive variable stiffness spring of the present invention.

[0028] The structures of the second spring 2 and the third spring 5 can be the same or different, and can be selected from coil springs, wave springs, rubber springs, buffer blocks, metal rubber shock absorbers, wire rope shock absorbers, etc. with the same or different parameters.

[0029] The cross section of the force transmission rod 9 is a regular polygon, and a regular polygonal through hole identical to the cross section of the force transmission rod 9 is opened in the center of the piston top plate 7-2. A regular polygonal first guide 4 is arranged on the regular polygonal through hole of the piston top plate 7-2 to cooperate with the force transmission rod 9. The force transmission rod 9 is sleeved inside the first guide 4, and there is a clearance fit between the first guide 4 and the force transmission rod 9. In this way, when the force transmission rod 9 moves up and down, the regular polygonal first guide 4 does not affect the up and down movement of the force transmission rod 9 relative to the piston 7, but restricts the rotation, lateral and flipping movement of the force transmission rod 9.

[0030] The outer circumferential surface of the force transmission plate 8 is provided with a second guide 6 that matches the inner surface of the cylinder of the piston 7. The second guide 6 is annular. The force transmission plate 8 matches the inner surface of the cylinder of the piston 7 through the second guide 6, which does not affect the up and down movement of the force transmission rod 9 relative to the piston 7 but restricts the lateral and flipping movement of the force transmission rod 9. The outer circumferential shape of the force transmission plate 8 is not a regular polygon but a circle. When the inner diameter of the cylinder of the piston 7 is constant, the outer diameters of the second spring 2 and the third spring 5 can be maximized, which is conducive to the optimized design of the structure of the third spring 5. Therefore, the force transmission rod 9 cooperates with the regular polygonal through hole on the piston top plate 7-2 through the first guide 4. In addition to limiting the relative torsional movement between the upper cover plate 1 and the piston 7, it also cooperates with the second guide 6 on the outer surface of the force transmission plate 8 and the inner surface of the cylinder of the piston 7 to limit the relative lateral and flipping movement between the upper cover plate 1 and the piston 7, avoiding lateral, torsional and flipping deformation of the airbag 3, thereby improving the safety of the airbag 3 and providing a guarantee for the normal performance of the air spring (i.e., the first spring).

[0031] The central axes of the force transmission rod 9, the piston 7, the force transmission plate 8, the second spring 2, the third spring 5, the airbag 3 and the upper cover plate 1 are collinear.

[0032] See also Figure 3 , based on the pre-set ride comfort improvement travel threshold f d1 , according to the suspension travel, it is divided into the lower body posture stability zone [-fd2 , -f d1 ), lower ride comfort improvement area [-f d1 ,0], upper riding comfort improvement area (0,f d1 ]、Upper body posture stability area (f d1 , f d2 ], where f d2 It is the upper and lower body posture stability area (f d1 , f d2 ]、[-f d2 , -f d1 ) of the suspension limit travel.

[0033] See also Figure 1 and Figure 3 When the car is driving on a bumpy or long wave undulating road, the solenoid valve 11 is opened, and the preset upper and lower riding comfort improvement travel thresholds [-f d1 , f d1 ], the multi-stage progressive variable stiffness spring of the present invention is operated by the air spring only according to the volume of the larger air chamber (i.e. the main air chamber + auxiliary air chamber 10 surrounded by the airbag 3, the upper cover plate 1, and the piston 7) and the smaller stiffness k0 to obtain better riding comfort. When the upward stroke of the upper cover plate 1 relative to the piston 7 exceeds the preset riding comfort improvement stroke threshold f d1 , the force transmission plate 8 moves upward, the upper end surface of the force transmission plate 8 contacts the lower end surface of the third spring 5 and compresses the third spring 5, so that a force is generated between the force transmission plate 8 and the piston top plate 7-2, and is transmitted to the upper cover plate 1 through the force transmission rod 9. That is, when the upward stroke of the upper cover plate 1 relative to the piston 7 exceeds the preset ride comfort improvement stroke threshold f d1 When the upper body posture is stable (f d1 , f d2 ], there are two forces acting between the upper cover plate 1 and the piston 7: the first force is the force generated by the air spring, and the second force is the force generated by the third spring 5. Therefore, the multi-stage progressive variable stiffness spring of the present invention works in parallel with the air spring and the third spring 5 to obtain better vehicle body posture stability. When the downward stroke of the upper cover plate 1 relative to the piston 7 exceeds the preset ride comfort improvement stroke threshold -f d1 When the lower body posture is stable, it is located in the lower body posture stable area [-f d2 , -f d1 ), the upper cover plate 1 moves downward, the lower end surface of the upper cover plate 1 contacts the upper end surface of the second spring 2 and compresses the second spring 2, so that a force is generated between the upper cover plate 1 and the piston top plate 7-2, that is, when the downward stroke of the upper cover plate 1 relative to the piston 7 exceeds the preset ride comfort improvement stroke threshold -f d1 When the lower body posture is stable, it is located in the lower body posture stable area [-fd2 , -f d1 ), two forces act between the upper cover plate 1 and the piston 7: the force generated by the air spring and the force generated by the second spring 2. The multi-stage progressive variable stiffness spring of the present invention works in parallel with the air spring and the second spring 2 to obtain better vehicle body posture stability.

[0034] When the car is traveling at high speed on a good road, the solenoid valve 11 is controlled to be closed, and the second spring 2 or the third spring 5 and the air spring are connected in parallel to provide greater stiffness according to the volume of the smaller air chamber (the main air chamber surrounded by the airbag 3, the upper cover plate 1, and the piston 7), and jointly provide stiffness, which is more conducive to improving the driving safety of the car.

[0035] In the upper and lower riding comfort improvement area (0, f d1 ]、[-f d1 ,0], except for the small stiffness generated by the air spring, when the second spring 2 and the third spring 5 respectively use springs with the same stiffness k1, the compression and tension body posture stability zone [-f d2 , -f d1 ) and (f d1 , f d2 ] to obtain the same stiffness, the present invention can obtain the following three sections and two stiffness characteristics:

[0036] The first paragraph: In the area of ​​improved riding comfort [-f d1 , f d1 ]: The air spring works according to the volume of the larger air chamber (the main air chamber + auxiliary air chamber 10 surrounded by the airbag 3, the upper cover plate 1, and the piston 7) to provide a smaller stiffness k0.

[0037] The second section: In the lower body posture stability zone [-f d2 , -f d1 ): The air spring provides a smaller stiffness k0 and the second spring 2 provides a stiffness k1 in parallel to form a stiffness k0+k1.

[0038] The third section: In the upper body posture stability area (f d1 , f d2 ]: The air spring provides a smaller stiffness k0 and the third spring 5 provides a stiffness k1 in parallel to form a stiffness k0+k1.

[0039] Since the stiffness k0+k1 is obviously greater than k0, when the suspension stroke transitions from the upper ride comfort improvement stroke section to the upper vehicle body posture stabilizing stroke section, or from the lower ride comfort improvement stroke section to the lower vehicle body posture stabilizing stroke section, the stiffness of the present invention is increased, that is, it is a multi-stage incremental variable stiffness spring.

[0040] In the area of ​​improved riding comfort [-f d1 , fd1 ] In addition to the small stiffness generated by the air spring, when the second spring 2 and the third spring 5 use springs with different stiffness k1 and k2 respectively, the upper and lower body posture stability areas [-f d2 , -f d1 ) and (f d1 , f d2 ] to obtain different stiffnesses, at this time the present invention can obtain the following three sections of three stiffness characteristics:

[0041] The first paragraph: In the area of ​​improved riding comfort [-f d1 , f d1 ]: Consists of an air spring with a smaller stiffness k0.

[0042] The second section: In the lower body posture stability zone [-f d2 , -f d1 ): The air spring provides a smaller stiffness k0 and the second spring 2 provides a stiffness k1 in parallel to form a stiffness k0+k1.

[0043] The second section: In the upper body posture stability area (f d1 , f d2 ]: A smaller stiffness k0 provided by the air spring is connected in parallel with the stiffness k2 provided by the third spring 5 to form a stiffness k0+k2.

[0044] When the second spring 2 is a wave spring with two-stage stiffness characteristics, the larger deformation section [f d1 , s1] range, is the section with smaller stiffness k3, in the smaller deformation section (s1, f d2 ] range, which is a section with greater stiffness k4, where f d1 <s1<f d2 , s1 is determined by the characteristics of the second spring 2 wave spring. The third spring 5 also uses a wave spring with two-stage stiffness characteristics. The larger deformation section [f d1 , s2] range, which is a section with smaller stiffness k5; the smaller deformation section (s2, f d2 ] range, that is, the section with greater stiffness k6, where f d1 <s2<f d2 , s2 is determined by the characteristics of the third spring 5, which is a wave spring. When the second spring 2 and the third spring 5 cooperate with the air spring, multiple stages of multiple increasing stiffness characteristics can be obtained.

[0045] When the second spring 2 is a wave spring having two-stage stiffness characteristics of smaller stiffness k3 and larger stiffness k4, and the third spring 5 is a spring of fixed stiffness k1, the following four-stage four-stage stiffness characteristics can be obtained:

[0046] The first paragraph: in the area of ​​improved riding comfort [-f d1 , f d1 ]: The air spring provides a smaller stiffness k0.

[0047] The second section: In the upper body posture stability area (f d1 , f d2 ]: The air spring provides a smaller stiffness k0 and the third spring 5 provides a stiffness k1 in parallel to form a stiffness k0+k1.

[0048] The third section: In the lower body posture stability zone [-f d2 , -f d1 ], the third spring 5 is in the beginning compression and large deformation section [f d1 , s2]: The air spring provides a smaller stiffness k0 and the third spring 5 at [f d1 , s2] range provides a smaller stiffness k5 in parallel to form a stiffness k0+k5.

[0049] The fourth section: In the lower body posture stable area [-f d2 , -f d1 ], the third spring 5 is in the smaller deformation section (s2, f d2 ]: The air spring provides a smaller stiffness k0 and the third spring 5 in the smaller deformation section (s2, f d2 ] range provides a larger stiffness k6 which is connected in parallel to form stiffness k0+k6.

[0050] When the second spring 2 adopts a wave spring having the two-stage stiffness characteristics, and the third spring 5 adopts a wave spring having the two-stage stiffness characteristics, and k3=k5, k4=k6, the present invention can obtain the following five-stage three stiffness characteristics:

[0051] The first paragraph: in the area of ​​improved riding comfort [-f d1 , f d1 ]: The air spring provides a smaller stiffness k0.

[0052] The second section: in the lower body posture stability zone [-f d2 , -f d1 ), the second spring 2 is in the beginning compression large deformation section [-s1, -f d1 ], the air spring provides a smaller stiffness k0 and the second spring 2 at [f d1 , s1] range provides a smaller stiffness k3 in parallel to form a stiffness k0+k3.

[0053] The third section: In the lower body posture stability zone [-f d2 , -f d1 ), the second spring 2 is in the small deformation section at the end of compression [-fd2 , -s1), the air spring provides a smaller stiffness k0 and the second spring 2 in the smaller deformation section (s1, f d2 ] range provides a larger stiffness k4 which is connected in parallel to form stiffness k0+k4.

[0054] The fourth section: In the upper body posture stability area (f d1 , f d2 ], the third spring 5 is in the beginning compression and large deformation section [f d1 , s2]: The air spring provides a smaller stiffness k0 and the third spring 5 at [f d1 , s2] range provides a smaller stiffness k5 in parallel to form a stiffness k0+k5.

[0055] The fifth section: In the upper body posture stability area (f d1 , f d2 ], the third spring 5 is in the smaller deformation section (s2, f d2 ]: The air spring provides a smaller stiffness k0 and the third spring 5 in the smaller deformation section (s2, f d2 ] range provides a larger stiffness k6 which is connected in parallel to form stiffness k0+k6.

[0056] Since k3=k5 and k4=k6, five sections and three stiffness characteristics are formed.

[0057] When the second spring 2 is a wave spring with two-stage stiffness characteristics, the third spring 5 is a wave spring with two-stage stiffness characteristics, and k3 is not equal to k5, and k4 is not equal to k6, the present invention can obtain the following five stages and five stiffness characteristics:

[0058] The first paragraph: in the area of ​​improved riding comfort [-f d1 , f d1 ]: Consists of an air spring with a smaller stiffness k0.

[0059] The second section: in the lower body posture stability zone [-f d2 , -f d1 ), the second spring 2 is in the beginning compression large deformation section [-s1, -f d1 ], the air spring provides a smaller stiffness k0 and the second spring 2 at [f d1 , s1] range provides a smaller stiffness k3 in parallel to form a stiffness k0+k3.

[0060] The third section: In the lower body posture stability zone [-f d2 , -f d1 ), the second spring 2 is in the small deformation section at the end of compression [-f d2 , -s1), the air spring provides a smaller stiffness k0 and the second spring 2 in the smaller deformation section (s1, fd2 ] range provides a larger stiffness k4 which is connected in parallel to form stiffness k0+k4.

[0061] The fourth section: In the upper body posture stability area (f d1 , f d2 ], the third spring 5 is in the beginning compression and large deformation section [f d1 , s2]: The air spring provides a smaller stiffness k0 and the third spring 5 at [f d1 , s2] range provides a smaller stiffness k5 in parallel to form a stiffness k0+k5.

[0062] The fifth section: In the upper body posture stability area (f d1 , f d2 ], the third spring 5 is in the smaller deformation section (s2, f d2 ]: The air spring provides a smaller stiffness k0 and the third spring 5 in the smaller deformation section (s2, f d2 ] range provides a larger stiffness k6 which is connected in parallel to form stiffness k0+k6.

[0063] Since k3 is not equal to k5 and k4 is not equal to k6, five sections and five stiffness characteristics are formed.

[0064] Since k0+k4>k0+k3>k0, and k0+k6>k0+k5>k0, when the suspension stroke transitions from the upper ride comfort improvement stroke zone to the upper vehicle body posture stable stroke zone, or from the lower ride comfort improvement stroke zone to the lower vehicle body posture stable stroke zone, the stiffness of the present invention is increased, and multiple stages and multiple incremental stiffness characteristics are obtained.

[0065] See also Figure 3 In the area of ​​improved ride comfort, the greater the suspension stiffness, the smaller the vibration isolation rate of the suspension, and the worse the ride comfort of the car. Therefore, when the passive suspension works with a fixed stiffness greater than k0, compared with the present invention working with a stiffness of k0, the ride comfort of the car provided by the suspension of the present invention is better. On the other hand, in the upper and lower travels of the suspension -f d2 、f d2 The wider the working range is, the greater the improvement of the ride comfort of the car. To prevent the suspension limit from being hit, the suspension travel is close to -f d2 、f d2 Therefore, the more stiffness characteristics the multi-stage progressive variable stiffness spring of the present invention can choose, the more generous the optimization design conditions for improving the overall performance of the suspension are, and the more conducive to improving the overall performance of the suspension.

[0066] Obviously, the vehicle body posture stabilization area is mainly provided with greater rigidity by the second spring 2 and the third spring 5, which effectively reduces the pressure in the airbag 3 and effectively improves the safety of the airbag.

Claims

1. A multi-stage progressive variable stiffness spring for automobile suspension, comprising a piston (7), an air bag (3) and an upper cover plate (1) connected in sequence from bottom to top, the upper cover plate (1) being connected upwardly to a vehicle body or a frame, the top of the piston (7) being a piston top plate (7-2) fixedly connected to the lower end of the air bag (3), the bottom of the piston (7) being a piston bottom plate (7-1) connected downwardly to an axle or a wheel, one end of an air pipe (12) being connected to the air bag (3), and the other end being connected to an additional air chamber (10), the air pipe (12) being provided with a solenoid valve (11), Features: The interior of the piston (7) is a hollow chamber, in which a force transmission plate (8) capable of moving up and down is arranged, the lower end of the force transmission rod (9) is fixedly connected to the middle of the force transmission plate (8), and passes through the piston top plate (7-2) and the air bag (3) in sequence upwards, and is fixedly connected to the upper cover plate (1), inside the air bag (3), a second spring (2) is sleeved on the outside of the force transmission rod (9), the lower end of the second spring (2) is fixedly connected to the upper end surface of the piston top plate (7-2), the upper end of the second spring (2) is a free end, or the lower end surface of the second spring (2) is set as a free end, and the upper end surface is fixedly connected to the lower end surface of the upper cover plate (1); in the initial state, the free end of the second spring (2) The third spring (5) is provided inside the piston (7), the upper end of the third spring (5) is fixedly connected to the lower end of the piston top plate (7-2), the lower end of the third spring (5) is a free end, or the upper end of the third spring (5) is configured as a free end, and the lower end is fixedly connected to the upper end of the force transmission plate (8), in an initial state, the free end of the third spring (5) is not in contact with the upper end of the force transmission plate (8) or the lower end of the piston top plate (7-2), and a distance of a preset threshold value of ride comfort improvement is left between them.

2. The multi-stage progressive variable stiffness spring for automobile suspension according to claim 1, Features: A regular polygonal through hole is provided on the piston top plate (7-2), the cross section of the force transmission rod (9) is a regular polygon, a regular polygonal first guide (4) is arranged on the regular polygonal through hole of the piston top plate (7-2) to cooperate with the force transmission rod (9), and the force transmission rod (9) is sleeved inside the first guide (4); a second guide (6) is arranged on the outer circumferential surface of the force transmission plate (8) to cooperate with the inner circumferential surface of the piston (7) cylinder.

3. The multi-stage progressive variable stiffness spring for automobile suspension according to claim 1, Features: The second spring (2) and the third spring (5) are respectively coil springs, wave springs, rubber springs, buffer blocks, metal rubber vibration dampers or wire rope vibration dampers with the same or different parameters.

4. The multi-stage progressive variable stiffness spring for automobile suspension according to claim 1, Features: The outer diameter of the second spring (2) is smaller than the outer diameter of the piston (7), and the outer diameter of the third spring (5) is smaller than the inner diameter of the piston (7); the central axes of the force transmission rod (9), the piston (7), the force transmission plate (8), the second spring (2), the third spring (5), the airbag (3), the upper cover plate (1), and the airbag (3) are collinear.

5. A method for operating the multi-stage progressive variable stiffness spring for automobile suspension according to any one of claims 1 to 4, Features: When the vehicle is traveling on a bumpy or long-wave undulating road surface, the solenoid valve (11) is opened, the upward stroke of the upper cover plate (1) relative to the piston (7) exceeds a preset threshold of ride comfort improvement stroke, the force transmission plate (8) moves upward to contact and compress the third spring (5), so that a force is generated between the force transmission plate (8) and the piston top plate (7-2) and transmitted to the upper cover plate (1) through the force transmission rod (9), and the air spring composed of the airbag (3), the upper cover plate (1) and the piston (7) and the third spring (5) work in parallel; When the downward stroke of the upper cover plate (1) relative to the piston (7) exceeds a preset threshold of the stroke for improving ride comfort, the upper cover plate (1) moves downward, contacts and compresses the second spring (2), so that a force is generated between the upper cover plate (1) and the piston top plate (7-2), and the air spring and the second spring (2) work in parallel; When the car is running at high speed on a good road, the control solenoid valve (11) is closed, and the second spring (2) or the third spring (5) is connected in parallel with the air spring with a larger stiffness provided by a smaller air chamber volume to jointly provide stiffness.

6. The working method according to claim 5, Features: When the second and third springs (2, 5) have the same stiffness k 1 Spring, in the ride comfort improvement area [-f d1 , f d1 ], the air spring works with a larger air chamber volume to provide a smaller stiffness k 0 ; In the lower body posture stability area [-f d2 , -f d1 ), the smaller stiffness k 0 The stiffness k provided by the second spring (2) 1 Parallel connection forms stiffness k 0 +k 1 ; In the upper body posture stability area (f d1 , f d2 ], the smaller stiffness k 0 The stiffness k provided by the third spring (5) 1 Parallel connection forms stiffness k 0 +k 1 ;f d1 is the travel threshold for ride comfort improvement, f d2 It is the upper and lower body posture stability area (f d1 , f d2 ]、[-f d2 , -f d1 ) of the suspension limit travel.

7. The working method according to claim 5, Features: When the second and third springs (2, 5) have different stiffness k 1 , k 2 When the spring is in the riding comfort improvement area [-f d1 , f d1 ] The air spring provides a small stiffness k 0 , in the lower body posture stable area [-f d2 , -f d1 ) The smaller stiffness k provided by the air spring 0 The stiffness k provided by the second spring (2) 1 Parallel connection forms stiffness k 0 +k 1 ; In the upper body posture stability area (f d1 , f d2 ]The smaller stiffness k provided by the air spring 0 The stiffness k provided by the third spring (5) 2 Parallel connection forms stiffness k 0 +k 2 ;f d1 is the travel threshold for ride comfort improvement, f d2 It is the upper and lower body posture stability area (f d1 , f d2 ]、[-f d2 , -f d1 ) of the suspension limit travel.

8. The working method according to claim 7, Features: When the second spring (2) is a wave spring with two-stage stiffness characteristics, the larger deformation section [f d1 ,s 1 ] range, for a smaller stiffness k 3 The section with the smaller deformation section (s 1 , f d2 ] range, for a larger stiffness k 4 The segment, f d1 1 <f d2 ,s 1 Determined by the characteristics of the second spring (2); the third spring (5) adopts a wave spring with two-stage stiffness characteristics, and the larger deformation section [f d1 ,s 2 ] range, for a smaller stiffness k 5 The section with the smaller deformation section (s 2 , f d2 ] range, for a larger stiffness k 6 The segment, f d1 2 <f d2 ,s 2 Determined by the characteristics of the third spring (5) wave spring, the second and third springs (2, 5) obtain multiple stages of multiple increasing stiffness characteristics when matched with the air spring.​​ 9. The working method according to claim 8, Features: When the second spring (2) is used with a smaller stiffness k 3 and larger stiffness k 4 Two-stage stiffness characteristic spring and the third spring (5) adopts fixed stiffness k 1 When the spring is used, the ride comfort improvement area [-f d1 , f d1 ] The air spring provides a small stiffness k 0 ; In the upper body posture stability area (f d1 , f d2 ]: The air spring provides a smaller stiffness k 0 The third spring (5) provides a stiffness k 1 Parallel connection forms stiffness k 0 +k 1 ; In the lower body posture stability area [-f d2 , -f d1 ], the third spring (5) is in the beginning compression and large deformation stage [f d1 ,s 2 ]: The air spring provides a smaller stiffness k 0 With the third spring (5) at [f d1 ,s 2 ] range provides a smaller stiffness k 5 Parallel connection forms stiffness k 0 +k 5 ; In the lower body posture stability area [-f d2 , -f d1 ], the third spring (5) is in a smaller deformation section (s 2 , f d2 ]: The air spring provides a smaller stiffness k 0 The third spring (5) is in a smaller deformation section (s 2 , f d2 ] range provides greater stiffness k 6 Parallel connection forms stiffness k 0 +k 6 ; When the second and third springs (2, 3) are wave springs having the two-stage stiffness characteristics described above, and k 3 =k 5 , k 4 =k 6 , in the area of ​​improved riding comfort [-f d1 , f d1 ] The air spring provides a small stiffness k 0 , in the lower body posture stable area [-f d2 , -f d1 ), the second spring (2) is in the beginning compression large deformation section [-s 1 , -f d1 ], by the smaller stiffness k 0 With the second spring (2) at [f d1 ,s 1 ] range provides a smaller stiffness k 3 Parallel connection forms stiffness k 0 +k 3 , in the lower body posture stable area [-f d2 , -f d1 ), the second spring (2) is in the small deformation section at the end of compression [-f d2 , -s 1 ), the smaller stiffness k provided by the air spring 0 The second spring (2) is in a smaller deformation section (s 1 , f d2 ] range provides greater stiffness k 4 Parallel connection forms stiffness k 0 +k 4 , in the upper body posture stable area (f d1 , f d2 ], the third spring (5) is in the beginning compression and large deformation stage [f d1 ,s 2 ], the smaller stiffness k provided by the air spring 0 With the third spring 5 at [f d1 ,s 2 ] range provides a smaller stiffness k 5 Parallel connection forms stiffness k 0 +k 5 ; Upper body posture stability area (f d1 , f d2 ], the third spring (5) is in a smaller deformation section (s 2 , f d2 ]: Smaller stiffness k provided by the air spring 0 The third spring (5) is in a smaller deformation section (s 2 , f d2 ] range provides greater stiffness k 6 Parallel connection forms stiffness k 0 +k 6 ; When the second and third springs (2, 3) are wave springs having the two-stage stiffness characteristics described above, and k 3 Not equal to k 5 , k 4 Not equal to k 6 , in the area of ​​improved riding comfort [-f d1 , f d1 ] The air spring provides a small stiffness k 0 , in the lower body posture stable area [-f d2 , -f d1 ), the second spring (2) is in the beginning compression large deformation section [-s 1 , -f d1 ], by the smaller stiffness k 0 With the second spring (2) at [f d1 ,s 1 ] range provides a smaller stiffness k 3 Parallel connection forms stiffness k 0 +k 3 ; In the lower body posture stability area [-f d2 , -f d1 ), the second spring (2) is in the small deformation section at the end of compression [-f d2 , -s 1 ), by the smaller stiffness k 0 The second spring (2) is in a smaller deformation section (s 1 , f d2 ] range provides greater stiffness k 4 Parallel connection forms stiffness k 0 +k 4 ; In the upper body posture stability area (f d1 , f d2 ], the third spring (5) is in the beginning compression and large deformation stage [f d1 ,s 2 ], by the smaller stiffness k 0 With the third spring (5) at [f d1 ,s 2 ] range provides a smaller stiffness k 5 Parallel connection forms stiffness k 0 +k 5 ; In the upper body posture stability area (f d1 , f d2 ], the third spring (5) is in a smaller deformation section (s 2 , f d2 ], by the smaller stiffness k 0 The third spring (5) is in a smaller deformation section (s 2 , f d2 ] range provides greater stiffness k 6 Parallel connection forms stiffness k 0 +k 6 .

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