A variable stiffness leaf spring management system

Abstract

The present invention relates to a variable stiffness leaf spring management system, wherein the adjustable stiffness suspension comprises a stiffness adjustment mode analysis module connected to a vehicle driving system, wherein the vehicle driving system can collect one or more of vehicle driving data, environmental data and load data through a number of sensors, and the stiffness adjustment mode analysis module comprises one or more of a road condition change detection unit, a load change detection unit, a load inertia change detection unit, a vehicle driving speed detection unit and a wheel contact detection unit, and the stiffness adjustment mode analysis module performs analysis based on the vehicle driving data, environmental data and load data and in combination with pre-stored mode conversion judgment conditions to determine at least one stiffness adjustment mode.

Description

[0001] The present invention is an application with application number 202010497555.7, application date June 3, 2020, application type is invention, and application name is a divisional application for a transverse leaf spring with adjustable stiffness suspension. Technical Field

[0002] The invention relates to the technical field of vehicle suspension systems, and in particular to a variable-rigidity leaf spring management system. Background Art

[0003] The application of transverse leaf springs on existing automobiles is relatively rare compared to longitudinal leaf springs. In vehicles using transverse leaf spring systems, the installation and fixing method of transverse leaf springs mostly adopts a hard point fixing structure, and the stiffness cannot be adjusted, resulting in huge development costs for parts development in the prototype trial stage, increasing costs, and many leaf springs are customized into special shapes, which increases mold development costs. At the same time, the two ends of the leaf spring and the connecting parts of the swing arm are mostly made of rubber parts, which are easy to age, have a short life, and are easy to change in properties, and will pollute the environment.

[0004] The prior art discloses a novel transverse leaf spring mounting structure proposed in the patent document with publication number CN209191623U, which belongs to the technical field of transverse leaf spring mounting structures, and comprises a swing arm and a leaf spring frame, wherein the two sides of the leaf spring frame are rotatably connected with the swing arms respectively, the leaf spring frame is located above the leaf spring body, the two sides of the leaf spring body are fixedly connected with leaf spring end adapter blocks respectively, the lifting ears are arranged between the swing arm and the leaf spring end adapter block, and the swing arm and the leaf spring end adapter block are rotatably connected with the lifting ears respectively, a leaf spring stiffness adjustment hole is arranged on the leaf spring frame, a leaf spring stiffness adjustment block is bolted to the leaf spring stiffness adjustment hole, a leaf spring locking block is connected to the leaf spring stiffness adjustment block by bolts, the leaf spring body is pressed between the leaf spring locking block and the leaf spring stiffness adjustment block, the leaf spring frame is fixedly connected to the leaf spring body by bolts passing through the central stiffness adjustment hole and the leaf spring stiffness adjustment screw mounting hole; the structure has the advantages of supporting adjustable leaf spring stiffness, low cost, high reliability and easy disassembly and assembly.

[0005] In view of the problem of the non-adjustable stiffness of the hard-point fixed leaf spring currently used in the art, the prior art, such as the above-mentioned patent, proposes a transverse leaf spring installation structure with adjustable stiffness, which mainly improves the stiffness by driving the pulley seats on both sides to move to both sides, and the pulleys gradually press the leaf spring to fit with the upper crossbeam, so that the curvature of the leaf spring and the free swing arm of the leaf spring are reduced at the same time. However, under this type of structure, the curvature of the leaf spring and the free swing arm of the leaf spring can only be adjusted synchronously, resulting in a small adjustment causing a large change in the stiffness of the leaf spring, poor adjustment sensitivity, and inability to adapt to different stiffness requirements under different driving conditions; at the same time, since it is impossible to achieve independent control of the stiffness and the balance position, each time the leaf spring stiffness is adjusted, a large load must be applied to the leaf spring to increase or decrease its curvature, resulting in frequent strain of the leaf spring and reduced fatigue life of the leaf spring, which is not conducive to the long-term use of the leaf spring.

[0006] The patent document with publication number CN110549806A in the prior art proposes a vehicle transverse leaf spring suspension system with continuous stiffness adjustment, including a pair of upper brackets, a pair of lower brackets and a transverse leaf spring; a continuous stiffness adjustment mechanism is provided on the transverse leaf spring; the continuous stiffness adjustment mechanism includes a pair of variable damping shock absorbers, a drive motor, a transmission mechanism and a pair of pulley mechanisms; the transmission mechanism includes a bidirectional lead screw and a pair of gears; the lead screw threads on both sides of the bidirectional lead screw have opposite rotation directions; the pulley mechanism includes an upper guide pulley, a lower guide pulley and a pulley seat; the upper guide pulley and the lower guide pulley are in an upper and lower clamping state with respect to the upper bracket crossbeam and the transverse leaf spring; when working, the drive motor drives the pair of pulley mechanisms to make uniform and same-direction or reverse linear movements through the transmission mechanism to adjust the degree of bending deformation of the transverse leaf spring, thereby realizing the stiffness adjustment of the transverse leaf spring.

[0007] The automobile transverse leaf spring suspension system proposed in the above-mentioned prior art can only synchronously adjust the left and right pulley mechanisms, and the adjustment ability is limited. When adjusting the stiffness of the system, the leaf spring located between the left and right pulley mechanisms is forced to bend with a large degree of deformation. It does not involve the technical solution proposed in this application that can determine the optimal stiffness adjustment mode that best meets the current vehicle speed and the upcoming driving conditions by detecting and analyzing the current vehicle's road conditions, load changes, load inertia changes, vehicle driving speed, and wheel contact conditions. In addition, on the one hand, due to differences in understanding among those skilled in the art; on the other hand, because the inventor studied a large number of documents and patents when making the present invention, but due to space limitations, not all the details and contents are listed in detail, however, this is by no means that the present invention does not have the characteristics of these prior arts. On the contrary, the present invention already has all the characteristics of the prior arts, and the applicant reserves the right to add relevant prior arts in the background art. Summary of the invention

[0008] In view of the problem of the non-adjustable stiffness of the hard-point fixed leaf spring currently used in the art, the prior art, such as the above-mentioned patent, proposes a transverse leaf spring installation structure with adjustable stiffness, which mainly improves the stiffness by driving the pulley seats on both sides to move to both sides, and the pulleys gradually press the leaf spring to fit with the upper crossbeam, so that the curvature of the leaf spring and the free swing arm of the leaf spring are reduced at the same time. However, under this type of structure, the curvature of the leaf spring and the free swing arm of the leaf spring can only be adjusted synchronously, resulting in a small adjustment causing a large change in the stiffness of the leaf spring, poor adjustment sensitivity, and inability to adapt to different stiffness requirements under different driving conditions; at the same time, since it is impossible to achieve independent control of the stiffness and the balance position, each time the leaf spring stiffness is adjusted, a large load must be applied to the leaf spring to increase or decrease its curvature, resulting in frequent strain of the leaf spring and reduced fatigue life of the leaf spring, which is not conducive to the long-term use of the leaf spring.

[0009] In this regard, the present invention proposes a stiffness-adjustable suspension of a transverse leaf spring that realizes at least three stiffness adjustment modes by cooperating with at least two leaf spring stiffness adjustment components. The stiffness adjustment mode analysis module detects and analyzes the current vehicle's road condition changes, load changes, load inertia changes, vehicle driving speed and wheel contact conditions in many aspects, and can determine the optimal stiffness adjustment mode that best suits the current vehicle speed and the upcoming driving conditions. The suspension, which cooperates between the first leaf spring stiffness adjustment component and the second leaf spring stiffness adjustment component, can achieve independent control of stiffness and equilibrium position, and can select both the leaf spring curvature and the leaf spring free swing arm for synchronous adjustment or asynchronous adjustment. It has good impact resistance and flexible dynamic characteristics, and can adapt to the constantly changing vehicle speed and road conditions during actual driving. At the same time, since the stiffness and the balance position can be controlled independently, each time the leaf spring stiffness is adjusted, only the position of the leaf spring fulcrum needs to be adjusted without applying pressure to the leaf spring to change the curvature. This minimizes the problem of reduced fatigue life of the leaf spring due to frequent adjustment of the leaf spring stiffness, which is beneficial to the long-term use of the leaf spring and reduces maintenance costs.

[0010] The present invention provides a stiffness-adjustable suspension for a transverse leaf spring, comprising a leaf spring and at least two first leaf spring stiffness adjustment components sleeved on the leaf spring, characterized in that it also includes at least one second leaf spring stiffness adjustment component, the second leaf spring stiffness adjustment component abuts against the plate surface of the leaf spring by being connected to at least one first leaf spring stiffness adjustment component, wherein the leaf spring can be switched among at least three stiffness adjustment modes through the cooperation of the first leaf spring stiffness adjustment component and the second leaf spring stiffness adjustment component, and the leaf spring curvature and the free swinging arm length of the leaf spring in different stiffness adjustment modes are adjusted independently of each other or adjusted in coupling with each other.

[0011] By cooperating the first leaf spring stiffness adjustment component with the second leaf spring stiffness adjustment component, facing different driving conditions that require adjustment of the leaf spring stiffness, it is possible to switch between at least three stiffness adjustment modes, which are respectively changing the leaf spring stiffness by independently adjusting the leaf spring curvature, changing the leaf spring stiffness by independently adjusting the leaf spring free swing arm length, and changing the leaf spring stiffness by coupling adjustment of the leaf spring curvature and the leaf spring free swing arm length. Under this setting, the stiffness adjustable suspension proposed by the present invention can achieve independent control of stiffness and equilibrium position, and can select synchronous adjustment or asynchronous adjustment of the leaf spring curvature and the leaf spring free swing arm, and has good impact resistance and flexible dynamic characteristics. Especially in the stiffness adjustment mode where both are asynchronously adjusted, the adjustment amplitude is equivalent to the adjustment amplitude between the leaf spring stiffness, and the adjustment sensitivity is excellent, which can better adapt to different stiffness requirements under different driving conditions. In addition, since the stiffness and the balance position can be independently controlled, each time the leaf spring stiffness is adjusted, only the position of the leaf spring fulcrum needs to be adjusted without applying pressure to the leaf spring to change the curvature. This minimizes the problem of reduced fatigue life of the leaf spring due to frequent adjustment of the leaf spring stiffness, which is beneficial to the long-term use of the leaf spring and reduces maintenance costs.

[0012] According to a preferred embodiment, the second leaf spring stiffness adjustment assembly includes at least one special-shaped roller arranged on the first leaf spring stiffness adjustment assembly, and a first adjustable interval for connecting the leaf spring is reserved between every two special-shaped rollers. The first adjustable interval can adapt to different leaf spring curvature changes in at least one stiffness adjustment mode based on the relative initial position relationship and / or relative rotation between the two special-shaped rollers.

[0013] The existing medium and light-duty automobiles usually use a leaf spring, which is composed of several steel plates with thin ends and thick middle, equal width and length. The characteristic of the leaf spring is that the steel plate is thicker in the center along the length direction and gradually becomes thinner towards the two ends. For the widely used leaf spring, the prior art, such as the automobile transverse leaf spring suspension system with continuous stiffness adjustment proposed in the patent document with publication number CN110549806A, can indeed achieve the purpose of leaf spring stiffness adjustment, but the clamping space of its pulley seat is fixed, resulting in its application being limited to a single leaf spring with uniform steel plate thickness, and it cannot be actually applied to the widely used leaf spring, and the application object is single. In this regard, the stiffness adjustable suspension proposed by the present invention adopts a special-shaped roller group as the second leaf spring stiffness adjustment component. Cam-type special-shaped rollers are important accessories of the valve train in this field, and are usually used individually in reciprocating linear motion or swinging mechanisms. However, in the present invention, two of them are grouped into a special-shaped roller group. By utilizing the new adjustable interval characteristic formed by the combination of the two, not only can the stiffness adjustment of a single leaf spring with consistent thickness and a small leaf spring with varying thickness be simultaneously satisfied, but the present invention also combines it with another leaf spring stiffness adjustment component, and is no longer limited to the traditional single stiffness adjustment method. Under the combined action of the two types of leaf spring stiffness adjustment components, the stiffness adjustable suspension proposed by the present invention has at least three stiffness adjustment modes. The conversion between the stiffness adjustment modes promotes the adjustment sensitivity of the leaf spring stiffness, and while better adapting to the different stiffness requirements under different driving conditions, it can maximize the protection of the fatigue life of the leaf spring.

[0014] According to a preferred embodiment, the adjustable stiffness suspension also includes a guide rail driving mechanism, and the first leaf spring stiffness adjustment assembly is mounted on the guide rail driving mechanism. Under the forward and reverse driving of the guide rail driving mechanism, every two first leaf spring stiffness adjustment assemblies move simultaneously along the longitudinal direction of the guide rail driving mechanism, so that the second adjustable interval between every two first leaf spring stiffness adjustment assemblies can adapt to the changes in the length of the freely swingable arm of different leaf springs in at least one stiffness adjustment mode.

[0015] In the present application, the guide rail driving mechanism adopts a gear rack transmission structure, which is different from the automobile transverse leaf spring suspension system commonly used in the prior art, such as the patent document with publication number CN110549806A. The existing scheme usually adopts a screw drive to achieve the position adjustment of the pulley seat. However, the screw drive will cause the transmission gap to become larger and the return accuracy to become worse after long-term use, and reliable and accurate adjustment cannot be achieved. In this regard, the present invention adopts a gear rack drive driving mechanism with a transmission accuracy of up to 0.1mm. On the one hand, the gear rack drive itself has better transmission accuracy and working reliability than the screw drive. The gear rack drive mechanism has a self-locking function. After the transmission adjustment, there is no need to give continuous power input, which saves energy. On the other hand, the present invention optimizes the structure of the drive mechanism and the relative position relationship between it and the leaf spring. The rack, leaf spring stiffness adjustment component and leaf spring in the drive mechanism are basically on the same working plane, so that the overall structure of the drive mechanism is compact and the center of gravity is low, which can reduce its occupied space and improve the driving stability of the vehicle.

[0016] According to a preferred embodiment, the adjustable stiffness suspension also includes a stiffness adjustment mode analysis module connected to a vehicle driving system, wherein the vehicle driving system can collect one or more of vehicle driving data, environmental data and load data through a number of sensors, and the stiffness adjustment mode analysis module includes one or more of a road condition change detection unit, a load change detection unit, a load inertia change detection unit, a vehicle driving speed detection unit and a wheel contact detection unit, and the stiffness adjustment mode analysis module performs analysis based on the vehicle driving data, environmental data and load data and in combination with pre-stored mode conversion judgment conditions to determine at least one stiffness adjustment mode.

[0017] During the actual driving process of a vehicle, the vehicle speed and the road conditions are constantly changing. The vehicle is required to have both driving safety and riding comfort. The stiffness control method of the vehicle suspension system plays a vital role in the performance of the suspension, which directly affects the handling stability, riding comfort and driving safety of the vehicle. In this regard, the automobile transverse leaf spring suspension system commonly used in the prior art, such as the patent document with the publication number CN110549806A, when the sensor detects that the number of passengers is different and the sprung mass changes, its suspension system controller adjusts the stiffness of the suspension system accordingly based on the load data collected by the pressure sensor. This type of solution can only adjust the appropriate suspension stiffness for static loads, and cannot adapt to the constantly changing vehicle speed and road conditions during actual driving. The sprung mass changes continuously during driving. The suspension system can only be adjusted with hysteresis, and the adjustment frequency is high, the leaf spring is frequently strained, and the fatigue life of the leaf spring is reduced, which is not conducive to the long-term use of the leaf spring. In this regard, the stiffness adjustable suspension of the present invention is further provided with a stiffness adjustment mode analysis module on the adjustable structure of the leaf spring stiffness adjustment component, which can determine the optimal stiffness adjustment mode that best matches the current vehicle speed and the upcoming driving road conditions by detecting and analyzing the current vehicle road condition changes, load changes, load inertia changes, vehicle driving speed, and wheel contact conditions, so that the suspension under the mutual cooperation between the first leaf spring stiffness adjustment component and the second leaf spring stiffness adjustment component has good impact resistance and flexible dynamic characteristics, and is adapted to the constantly changing vehicle speed and road conditions during actual driving. Since the stiffness adjustment mode analysis module analyzes the road conditions ahead, there is no problem of hysteresis adjustment in the prior art, and in the driving state with a high stiffness adjustment frequency requirement, the stiffness adjustment mode is automatically converted to a mode of independently adjusting the free swing arm length of the leaf spring, without the need for frequent strain of the leaf spring, thereby effectively delaying the fatigue life of the leaf spring.

[0018] According to a preferred embodiment, one or more of the road condition change detection unit, the load inertia change detection unit, the vehicle driving speed detection unit and the wheel contact detection unit respectively calculate the first data, the second data, the third data and the fourth data based on one or more of the acquired vehicle driving data, environmental data and load data, and the stiffness adjustment mode analysis module processes the first to fourth data to determine at least one stiffness adjustment mode.

[0019] According to a preferred embodiment, the adjustable stiffness suspension also includes a load change detection unit for acquiring fifth data, the load inertia change detection unit is used to determine the load application object according to the current vehicle usage type, and determine the distribution of the load application object in the vehicle according to the fifth data acquired by the load change detection unit during the initialization time period, based on the load application object and the distribution of the load application object in the vehicle, the second data is predicted and obtained, and the second data is related to the load change of the leaf spring caused by the load during the vehicle driving process.

[0020] The load inertia change detection unit is related to the load application object in the current vehicle. The vehicle usage types mentioned here are mainly small and medium-sized cars and small and medium-sized transport vehicles, that is, the load application objects may be passengers, solid objects and liquid objects. For different load application objects, their inertia, that is, the ability to maintain a stationary state under the action of external forces, is different. The inertia of the load application object in the vehicle seriously affects the load borne by the suspension. In this regard, the present application pre-collects the load application objects in the vehicle to predict the impact of their inertia on the suspension load, so that the stiffness adjustment requirements can better fit the actual driving conditions, and combines the load inertia change with multiple other influencing factors. Through feature extraction, it can quickly process and complete the operation process of mode conversion judgment, and the system has a fast response speed and high reliability.

[0021] According to a preferred embodiment, each stiffness adjustment mode in the mode conversion judgment condition corresponds to a different feature set, and the stiffness adjustment mode analysis module determines at least one stiffness adjustment mode by processing the first to fourth data to extract the feature set. By means of feature extraction and mode conversion judgment, the traditional method of a single stiffness adjustment mode is abandoned, and on the basis of being able to quickly complete the establishment of a feature description set and match the feature set, a suspension system with multiple stiffness adjustment modes with fast response speed and high reliability is realized.

[0022] According to a preferred embodiment, in different stiffness adjustment modes, the adjustment ratio of the leaf spring curvature and the leaf spring freely swingable arm length to the leaf spring stiffness is determined by the feature set so that they can be adjusted independently of each other or coupled with each other.

[0023] The present invention also proposes a stiffness control method for a stiffness-adjustable suspension based on a transverse leaf spring, characterized in that the method includes the following steps: based on the relative initial position relationship and / or relative rotation between the two special-shaped rollers, regulating the first adjustable interval reserved between the two special-shaped rollers for connecting the leaf spring, so that the first adjustable interval can adapt to different leaf spring curvature changes in at least one stiffness adjustment mode; under the forward and reverse drive of the guide rail drive mechanism, every two first leaf spring stiffness adjustment components move along the longitudinal direction of the guide rail drive mechanism at the same time, so that the second adjustable interval between every two first leaf spring stiffness adjustment components can adapt to different leaf spring free swing arm length changes in at least one stiffness adjustment mode; the first leaf spring stiffness adjustment component cooperates with the second leaf spring stiffness adjustment component, and the leaf spring can be switched between at least three stiffness adjustment modes, and the leaf spring curvature and the leaf spring free swing arm length of the leaf spring in different stiffness adjustment modes are adjusted independently of each other or coupled with each other.

[0024] The stiffness of the leaf spring when unloaded / fully loaded corresponds to the unloaded / fully loaded front axle load, respectively. The difference in ride comfort when the vehicle is unloaded and fully loaded is small, and both unloaded and fully loaded ride comfort are good. The elastic element / leaf spring of the independent suspension in the present invention is built into the crossbeam of the subframe, which has a compact structure and reduces the occupied space. The elastic element used in the independent suspension has a simple structure, mature technology, easy manufacturing, and low production cost. The overall structure of the independent suspension is simple, easy to maintain and repair, and the maintenance cost is also low. It solves the problem of a single elastic element on one side of the rear suspension of existing commercial vehicles, and the large difference in ride comfort when unloaded and fully loaded. It also solves the problem of small load capacity of the previous independent suspension, and can meet the needs of commercial vehicles with large axle loads.

[0025] The present invention also proposes a suspension experimental building platform with adjustable stiffness, comprising a large frame, a small frame and a leaf spring, wherein the leaf spring spans the small frame, and is characterized in that a simulated load-bearing platform and a driving mechanism are respectively mounted on the upper and lower supporting end surfaces of the small frame, and the driving mechanism is equipped with at least one leaf spring stiffness adjustment component for sleeve-connecting the leaf spring, wherein, when the small frame is driven to slide controllably along the large frame body so that the load parameters applied by the simulated load-bearing platform to the leaf spring change, the adjustable gap between at least two leaf spring stiffness adjustment components can be changed by the forward and reverse driving of the driving mechanism to achieve adaptive adjustment of the leaf spring stiffness.

[0026] When conducting a stiffness adjustment experiment, the size and distribution of the load applied to the leaf spring can be adjusted by changing the weight and arrangement of objects on the simulated load-bearing platform; by controlling the small frame to slide up and down along the large frame body, the load applied to the leaf spring by the simulated load-bearing platform can be converted between static load and alternating load, so as to simulate and analyze the performance of the leaf spring; through the forward and reverse driving of different driving mechanisms, the adjustable gap between several leaf spring stiffness adjustment components can be changed, and the adjustable gap directly affects the leaf spring curvature and the length of the leaf spring's freely swingable arm, so that the stiffness of the leaf spring can be adaptively adjusted in this experiment to study optimization solutions that are more suitable for different driving conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a simplified overall structural schematic diagram of the suspension experiment building platform provided by the present invention;

[0028] Figure 2 It is a simplified schematic diagram of the module connection relationship of the stiffness adjustable suspension provided by the present invention;

[0029] Figure 3 is a simplified overall structural schematic diagram of the leaf spring stiffness adjustment assembly provided by the present invention; and

[0030] Figure 4 It is a simplified overall structural schematic diagram of the second leaf spring stiffness adjustment assembly in Example 1 provided by the present invention.

[0031] Reference numerals list

[0032] 1: Rear large gear 2: Front large gear

[0033] 3: Rear rack 4: Car body

[0034] 5: Leaf spring 6: Driven pinion

[0035] 7: Connecting shaft 8: Driving pinion

[0036] 9: Motor shaft 10: Front rack

[0037] 11: Locking member 12: First leaf spring stiffness adjustment assembly

[0038] 13: Second leaf spring stiffness adjustment component 14: Special-shaped roller

[0039] 15: Guide rail drive mechanism 16: Stiffness adjustment mode analysis module

[0040] 17: Vehicle driving system 18: Road condition change detection unit

[0041] 19: Load change detection unit 20: Load inertia change detection unit

[0042] 21: Vehicle speed detection unit 22: Wheel contact detection unit

[0043] 23: Large frame 24: Small frame

[0044] 25: Simulated load-bearing platform 111: Welding block

[0045] 112: Guide rail slider 113: Roller

[0046] 114: Roller shaft DETAILED DESCRIPTION

[0047] The present invention is described in detail below with reference to the accompanying drawings.

[0048] Example 1

[0049] like Figure 1 What is shown is a simplified overall structural schematic diagram of the suspension experiment building platform provided by the present invention.

[0050] The suspension experiment building platform includes a large frame 23, a small frame 24 and a leaf spring 5. The small frame 24 is controllably slidably connected to the inside of the large frame 23. The leaf spring 5 spans the small frame 24. The upper and lower receiving end surfaces of the small frame 24 are respectively provided with a simulated load-bearing platform 25 and a driving mechanism.

[0051] like Figure 1 As shown, the driving mechanism includes a rear large gear 1, a front large gear 2, a rear rack 3, a motor shaft 9, a driving pinion 8, a driven pinion 6, a connecting shaft 7 and a front rack 10. The driving pinion 8 and the rear large gear 1 rotate coaxially through the motor shaft 9. The driven pinion 6 and the front large gear 2 rotate coaxially through the connecting shaft 7. The driving pinion 8 is in direct meshing contact with the driven pinion 6. The front large gear 2 and the rear large gear 1 are meshed with the front rack 10 and the rear rack 3 respectively, and drive the front and rear racks to move in opposite directions at the same speed, playing a driving role.

[0052] The lower receiving end surface also includes a locking mechanism. The locking mechanism includes a motor shaft 9 and a locking member 11. The locking member 11 slides on the guide rail of the vehicle body 4. The locking member 11 includes a welding block 111, a guide rail slider 112, a roller 113 and a roller shaft 114. The motor shaft 9 is connected to the motor. The motor itself has a self-locking function. The welding block 111 is welded to the rear rack 3 and the guide rail slider 112, so that the rear rack 3 moves with the locking member 11.

[0053] The guide rail slider 112 in the locking mechanism not only bears the weight of the vehicle body 4, but also slides on the vehicle body 4, so a lubricating material is applied to the surface of the guide rail portion on the vehicle body 4. Compared with the existing large-axle-load commercial vehicles, the suspension test building platform proposed by the present invention has an equivalent mean value reduced by 5 to 12 dB and good smoothness. Due to the relatively large load-bearing mass, the guide rail slider 112 and the roller 113 are made of alloy steel as a whole.

[0054] The roller 113 is fixed on the guide rail slider 112 through the roller shaft 114. When bearing the mass of the vehicle body, the roller 113 and the leaf spring 5 are in direct contact. The roller shaft 114 and the welding block 111 are both made of Q235 structural steel, which has excellent weldability, strength and plasticity, so that the roller 113 and the leaf spring 5 can have a closer contact. When the locking member 11 moves on the vehicle body 4, because the roller 113 and the leaf spring 5 are rolling friction, the friction force is tangential to the roller 113, so the friction force will not be very large. The suspension experiment building platform proposed by the present invention perfectly combines independent suspension, leaf spring 5 suspension, etc., and replaces traditional bulky and complex I-beams and other components with transverse leaf springs 5. It has a simple structure, low cost and great practical value.

[0055] When in use, a number of sensors sense the changes in the weight carried by the vehicle body and feed back to the controller. The controller controls the motor to rotate forward, reverse or stop. The motor shaft 9 drives the rear gear 1 and the active pinion 8 to move. After the intermediate torque is transmitted, the front rack 10 and the rear rack 3 finally move in opposite directions at the same speed, thereby achieving the purpose of controlling the movement of the locking member 11. When the locking member 11 reaches the target position, the motor self-locks. The roller 113 of the locking member 11 clamps the leaf spring 5. The locking member 11 positioned near the center of the leaf spring 5 provides a softer suspension. The locking member 11 located near the edge of the leaf spring 5 provides a harder suspension.

[0056] The structural setting of the suspension test platform proposed by the present invention solves the problem of a single elastic element on one side of the existing commercial vehicle rear suspension, and the large difference in ride comfort when empty and fully loaded. It also solves the problem of small load capacity of the previous independent suspension, and can meet the needs of large axle load commercial vehicles.

[0057] The stiffness of the leaf spring 5 when unloaded / fully loaded corresponds to the unloaded / fully loaded front axle load, respectively. The ride comfort when the vehicle is unloaded and fully loaded is slightly different, and both unloaded and fully loaded ride comfort are good. The elastic element / leaf spring 5 of the independent suspension of the present invention is built into the crossbeam of the subframe, and the structure is compact, which reduces the occupied space. The elastic element used in the independent suspension has a simple structure, mature technology, easy manufacturing, and low production cost. The overall structure of the independent suspension is simple, easy to maintain and repair, and the maintenance cost is also low.

[0058] In addition, under the structural setting of the suspension test platform proposed by the present invention, the plate body of the leaf spring 5 sequentially crosses at least one leaf spring stiffness adjustment component (i.e., a locking mechanism and a driving mechanism), and its two ends are stabilized by two support platforms. When conducting a stiffness adjustment experiment, the weight and arrangement position of the object on the simulated load-bearing platform 25 can be changed to adjust the load size and load distribution applied to the leaf spring 5; the small frame 24 can be controlled to slide up and down along the frame of the large frame 23, so that the load applied to the leaf spring 5 by the simulated load-bearing platform 25 can be converted between a static load and an alternating load, so as to simulate and analyze the performance of the leaf spring 5; the adjustable gap between several leaf spring stiffness adjustment components can be changed through the forward and reverse driving of different driving mechanisms, and the adjustable gap directly affects the leaf spring curvature and the free swing arm length of the leaf spring 5, so that the stiffness of the leaf spring 5 can be adaptively adjusted in this experiment, so as to study the optimization solution that is more suitable for different driving conditions.

[0059] Example 2

[0060] This embodiment provides a suspension with adjustable stiffness of a transverse leaf spring. This embodiment may be a further improvement and / or supplement to Embodiment 1, and repeated contents will not be repeated. In the case of no conflict or contradiction, the whole and / or part of the preferred implementation methods of other embodiments may be used as a supplement to this embodiment.

[0061] The adjustable stiffness suspension includes two first leaf spring stiffness adjustment components 12 and two second leaf spring stiffness adjustment components 13. Each first leaf spring stiffness adjustment component 12 is equipped with a second leaf spring stiffness adjustment component 13. The first leaf spring stiffness adjustment component 12 (i.e., the locking member 11) is a frame structure. The second leaf spring stiffness adjustment component 13 is composed of two special-shaped rollers 14 (i.e., rollers 113). During assembly, the two special-shaped rollers 14 are arranged on the upper and lower inner walls of the first leaf spring stiffness adjustment component 12. A first adjustable interval is reserved between the two special-shaped rollers 14, and the leaf spring 5 passes through the first adjustable interval and is mounted in the crossbeam of the subframe.

[0062] By cooperating with the first leaf spring stiffness adjustment component 12 and the second leaf spring stiffness adjustment component 13, three stiffness adjustment modes can be determined. The leaf spring curvature and the leaf spring freely swingable arm length of the leaf spring 5 in different stiffness adjustment modes are adjusted independently of each other or coupled with each other. The two are adjusted independently of each other means that in a stiffness adjustment mode, when the leaf spring curvature changes / the leaf spring freely swingable arm length is adjusted alone, the leaf spring freely swingable arm length / the leaf spring curvature is not affected and does not change; that is, the leaf spring curvature change or the leaf spring freely swingable arm length can be adjusted alone. The two are coupled with each other and adjusted together means that in a stiffness adjustment mode, when the leaf spring curvature / the leaf spring freely swingable arm length is adjusted alone, the leaf spring freely swingable arm length / the leaf spring curvature will be affected synchronously at the same time.

[0063] By cooperating with the first leaf spring stiffness adjustment component 12 and the second leaf spring stiffness adjustment component 13, facing different driving conditions that require adjustment of the leaf spring stiffness, it is possible to switch between at least three stiffness adjustment modes, which are respectively changing the leaf spring stiffness by independently adjusting the leaf spring curvature, changing the leaf spring stiffness by independently adjusting the leaf spring free swing arm length, and changing the leaf spring stiffness by coupling adjustment of the leaf spring curvature and the leaf spring free swing arm length. Under this setting, the stiffness adjustable suspension proposed by the present invention can achieve independent control of stiffness and equilibrium position, and can choose to adjust the leaf spring curvature and the leaf spring free swing arm synchronously or asynchronously. In particular, in the stiffness adjustment mode where the two are adjusted asynchronously, the adjustment amplitude is equivalent to the adjustment amplitude between the leaf spring stiffness, and the adjustment sensitivity is excellent, which can better adapt to different stiffness requirements under different driving conditions. In addition, since the stiffness and the equilibrium position can be independently controlled, each time the leaf spring stiffness is adjusted, only the position of the leaf spring fulcrum needs to be adjusted without applying pressure to the leaf spring 5 to change the curvature. This minimizes the problem of reduced fatigue life of the leaf spring 5 due to frequent adjustment of the leaf spring stiffness, which is beneficial to the long-term use of the leaf spring 5 and reduces maintenance costs.

[0064] A first adjustable interval for connecting the leaf spring 5 is reserved between each two shaped rollers 14 of the second leaf spring stiffness adjustment assembly 13. The shaped roller 14 may be a cam-type roller with a curved profile. Since the two shaped rollers 14 are arranged on the upper and lower inner walls of the first leaf spring stiffness adjustment assembly 12 opposite to each other, the two shaped rollers 14 are driven to rotate relative to each other, and the vertical distance (i.e., the first adjustable interval) between the adjacent outer walls of the two shaped rollers 14 can be adjusted. The existing medium and light-duty automobiles usually use a leaf spring, which is composed of several steel plates with thin ends and thick middle, equal width and length. The characteristic of the leaf spring is that the steel plate is thicker in the center along the length direction and gradually becomes thinner towards the two ends. For the widely used leaf spring, the prior art, such as the automobile transverse leaf spring suspension system with continuous stiffness adjustment proposed in the patent document with publication number CN110549806A, can indeed achieve the purpose of adjusting the stiffness of the leaf spring, but the clamping space of the pulley seat is fixed, resulting in its application being limited to a single leaf spring 5 with uniform steel plate thickness, which cannot be actually applied to the widely used leaf spring, and the application object is single. In this regard, the stiffness adjustable suspension proposed by the present invention adopts a group of special-shaped rollers 14 as the second leaf spring stiffness adjustment component 13. The cam-type special-shaped roller 14 is an important accessory of the valve system in the field, and it is usually used individually in a reciprocating linear motion or swing mechanism. But in the present invention, two of them are grouped into a group to form a group of special-shaped rollers 14. By utilizing the new adjustable interval characteristic formed by the combination of the two, not only can the stiffness adjustment of the single leaf spring 5 with consistent thickness and the small leaf spring with variable thickness be satisfied at the same time, but the present invention also combines it with another leaf spring stiffness adjustment component, and is no longer limited to the traditional single stiffness adjustment method. Under the combined action between the two types of leaf spring stiffness adjustment components, the stiffness adjustable suspension proposed by the present invention has at least three stiffness adjustment modes. The conversion between the stiffness adjustment modes promotes the adjustment sensitivity of the leaf spring stiffness, and while better adapting to the different stiffness requirements under different driving conditions, it can maximize the protection of the fatigue life of the leaf spring 5.

[0065] The first adjustable interval can adapt to different leaf spring curvature changes in at least one stiffness adjustment mode based on the relative initial position relationship and / or relative rotation between the two special-shaped rollers 14. The relative rotation between the two special-shaped rollers 14 mainly refers to independently driving the two special-shaped rollers 14 to rotate when adjusting the stiffness of the leaf spring. The relative initial position relationship between the two special-shaped rollers 14 refers to driving at least one special-shaped roller 14 to rotate in order to make the first adjustable interval between the upper and lower special-shaped rollers 14 match the current leaf spring thickness. At this time, the relative posture between the two special-shaped rollers 14, which may be the same or different, is the relative initial position. In this way, the second stiffness adjustment component can match different leaf springs 5 ​​with different thicknesses, and is particularly suitable for stiffness adjustment of leaf springs with varying thicknesses.

[0066] The adjustable stiffness suspension also includes a guide rail drive mechanism 15 (i.e., a drive mechanism for adjusting the first leaf spring stiffness adjustment component 12). The first leaf spring stiffness adjustment component 12 is mounted on the guide rail drive mechanism 15 (i.e., a locking mechanism). Under the forward and reverse drive of the guide rail drive mechanism 15, the two first leaf spring stiffness adjustment components 12 can simultaneously move along the longitudinal direction of the guide rail drive mechanism 15, thereby changing the second adjustable interval between the two first leaf spring stiffness adjustment components 12. The change in the second adjustable interval, i.e., the movement of the fulcrum position on the leaf spring 5, increases or decreases the length of the leaf spring freely swingable arm defined between the leaf spring 5 and the support platform. It can adapt to different changes in the length of the leaf spring freely swingable arm in at least one stiffness adjustment mode.

[0067] In the present application, the guide rail driving mechanism 15 adopts a gear rack transmission structure. Different from the automobile transverse leaf spring suspension system commonly used in the prior art, such as the patent document with publication number CN110549806A, the existing scheme usually adopts a screw drive to achieve the position adjustment of the pulley seat. However, the screw drive will cause the transmission gap to become larger and the return accuracy to become worse after long-term use, and reliable and accurate adjustment cannot be achieved. In this regard, the present invention adopts a gear rack drive driving mechanism with a transmission accuracy of up to 0.1mm. On the one hand, the gear rack drive itself has better transmission accuracy and working reliability than the screw drive. On the other hand, the present invention optimizes the structure of the driving mechanism and the relative position relationship between it and the leaf spring 5. The rack, leaf spring stiffness adjustment component and leaf spring 5 in the driving mechanism are basically on the same working plane, so that the overall structure of the driving mechanism is compact and the center of gravity is low, which can reduce its occupied space and improve the driving stability of the vehicle.

[0068] The stiffness adjustable suspension also includes a stiffness adjustment mode analysis module 16 connected to a vehicle driving system 17. The vehicle driving system 17 can collect vehicle driving data, environmental data and load data through a number of sensors. The stiffness adjustment mode analysis module 16 includes a road condition change detection unit 18, a load change detection unit 19, a load inertia change detection unit 20, a vehicle driving speed detection unit 21 and a wheel contact detection unit 22. The stiffness adjustment mode analysis module 16 is used to perform comprehensive processing on at least one data processed by a number of units, and perform mode conversion judgment, so as to determine at least one stiffness adjustment mode.

[0069] The adjustable stiffness suspension also includes a load change detection unit 19 for acquiring fifth data. The load change detection unit 19 is used to calculate the current load size and load distribution on the vehicle based on the measurement values ​​collected by a number of sensors installed on the vehicle when the vehicle starts (or is considered to be in the initialization time period). In the initialization time period, the load inertia change detection unit 20 determines the distribution of the load application object in the vehicle based on the fifth data acquired by the load change detection unit 19.

[0070] The load inertia change detection unit 20 is used to determine the load application object according to the current vehicle usage type. The vehicle usage type is, for example, a small car, a medium-sized car and a small and medium-sized transport vehicle. For small cars and medium-sized cars, the load application object in the vehicle can be determined to be a passenger or a solid object. Such load application objects are in a static state under the action of external forces and have a small inertia. For small and medium-sized transport vehicles, the transported items can be manually entered by the driver or photographed and recorded. They may be solid objects with small inertia or liquid objects with large inertia. The load inertia change detection unit 20 is connected to the cloud server. When the name of the liquid transport object is entered, the viscosity parameters (such as Reynolds number, the smaller the Reynolds number, the more significant the influence of the viscosity force, and the larger the Reynolds number, the more significant the influence of inertia). The viscosity of the liquid transport object under the current environmental data (such as temperature) can be queried and retrieved from the cloud server.

[0071] The load inertia change detection unit 20 predicts and obtains the second data based on the load application object and the distribution of the load application object in the vehicle. The second data is related to the load change of the leaf spring 5 caused by the load during the driving of the vehicle. During the driving of the vehicle, the weight, distribution and inertia of the load application object in the vehicle have a great influence on the load condition of the vehicle. The load inertia change detection unit 20 can establish a predictive correlation relationship between the independent variable parameters and the dependent variable parameters under different driving conditions based on the historical vehicle data in the cloud server. The independent variable parameters are the weight, distribution and inertia of the load application object in the vehicle. The dependent variable parameters are the vehicle load condition (load size and / or load distribution).

[0072] The road condition change detection unit 18 is used to calculate the first data in real time according to one or more of the vehicle driving data and the environmental data obtained. The vehicle driving speed detection unit 21 is used to calculate the third data in real time according to the vehicle driving data obtained. The wheel contact detection unit 22 is used to calculate the fourth data in real time according to the vehicle driving data obtained. The first data, the third data and the fourth data are all related to the driving condition.

[0073] The stiffness adjustment mode analysis module 16 processes the first data, the third data and the fourth data about the driving condition based on the predicted association relationship, and can quickly retrieve the predicted second data corresponding to the predicted association relationship. The stiffness adjustment mode analysis module 16 processes the first to fourth data based on several features in the mode conversion determination condition, and obtains a feature set after processing. Each stiffness adjustment mode in the mode conversion determination condition corresponds to a different feature set, so that the stiffness adjustment mode analysis module 16 can determine at least one stiffness adjustment mode.

[0074] The several features include the first to the ninth features: emergency braking, full load or large load, high-speed driving, convex humps, deep pits, potholes, one-sided wheel off the ground, curves, flat roads. The stiffness adjustment mode includes the first to the third mode: changing the leaf spring stiffness by independently adjusting the leaf spring curvature, changing the leaf spring stiffness by independently adjusting the leaf spring free swing arm length, and changing the leaf spring stiffness by coupling the leaf spring curvature and the leaf spring free swing arm length. The independent regulation of a certain parameter mentioned in the present invention to change the leaf spring stiffness does not mean that only one parameter can be changed while other parameters remain unchanged, but the change in the leaf spring stiffness is only caused by the change of a certain parameter. Therefore, especially for the less leaf spring with varying thickness, in the second mode, when it is necessary to drive the two first leaf spring stiffness adjustment components 12 to move toward or away from each other, according to the pre-acquired plate body parameters of the less leaf spring, drive the second leaf spring stiffness adjustment component 13 to rotate, so that the first adjustable gap between the second leaf spring stiffness adjustment components 13 can adapt to the different plate body thicknesses of the less leaf spring.

[0075] The mode conversion judgment condition can be set to a first feature set including the first feature and the eighth feature, which corresponds to the third mode. The second feature set including the seventh feature and the fourth feature, the third feature set including the seventh feature and the fifth feature, and the fourth feature set including the second feature, the third feature and the sixth feature all correspond to the first mode. The fifth feature set including only the ninth feature corresponds to the second mode. When the second leaf spring stiffness adjustment component 13 has reached its adjustable limit for the curvature of the leaf spring, or when the first leaf spring stiffness adjustment component 12 has reached its adjustable limit for the length of the freely swingable arm of the leaf spring, the stiffness adjustment mode is actively converted.

[0076] In different stiffness adjustment modes, the adjustment ratio of the leaf spring curvature and the leaf spring freely swingable arm length to the leaf spring stiffness is determined by the feature set.

[0077] It should be noted that the above specific embodiments are exemplary, and those skilled in the art can come up with various solutions inspired by the disclosure of the present invention, and these solutions also belong to the disclosure scope of the present invention and fall within the protection scope of the present invention. Those skilled in the art should understand that the present invention description and its drawings are illustrative and do not constitute a limitation of the claims. The protection scope of the present invention is defined by the claims and their equivalents.

Claims

1. A variable stiffness leaf spring management system, characterized in that: The variable stiffness leaf spring management system comprises a stiffness adjustment mode analysis module (16) connected to a vehicle driving system (17), wherein: The vehicle driving system (17) can collect one or more of the vehicle driving data, environmental data and load data through a plurality of sensors. The stiffness adjustment mode analysis module (16) comprises one or more of a road condition change detection unit (18), a load change detection unit (19), a load inertia change detection unit (20), a vehicle travel speed detection unit (21) and a wheel contact detection unit (22). The stiffness adjustment mode analysis module (16) performs analysis based on vehicle travel data, environmental data and load data and in combination with a number of features in the pre-stored mode conversion judgment conditions to determine a different feature set corresponding to each stiffness adjustment mode of the transverse leaf spring (5), thereby determining at least one stiffness adjustment mode including adjusting the leaf spring curvature of the leaf spring stiffness, adjusting the length of the freely swingable arm or coupling adjusting the leaf spring curvature and the length of the leaf spring freely swingable arm according to the feature set, wherein, when the first leaf spring stiffness adjustment component and the second leaf spring stiffness adjustment component cooperate with each other and the stiffness and the equilibrium position are independently controlled, the leaf spring curvature and the leaf spring freely swingable arm are selected as synchronous adjustment or asynchronous adjustment; Furthermore, the stiffness adjustment mode analysis module (16) determines the adjustment ratio of the leaf spring curvature and the leaf spring freely swingable arm length to the leaf spring stiffness. Each time the leaf spring stiffness is adjusted, only the fulcrum position of the leaf spring (5) is adjusted, and there is no need to apply pressure to the leaf spring (5) to change the curvature.

2. The variable stiffness leaf spring management system according to claim 1, characterized in that: One or more of the road condition change detection unit (18), the load inertia change detection unit (20), the vehicle travel speed detection unit (21) and the wheel contact detection unit (22) respectively calculate first data, second data, third data and fourth data based on one or more of the acquired vehicle travel data, environmental data and load data, and the stiffness adjustment mode analysis module (16) processes the first to fourth data to determine at least one stiffness adjustment mode.

3. The variable stiffness leaf spring management system according to claim 2, characterized in that: The variable stiffness leaf spring management system further comprises a load change detection unit (19) for acquiring fifth data, and a load inertia change detection unit (20) for determining a load application object according to a current vehicle usage type.

4. The variable stiffness leaf spring management system according to claim 3, characterized in that: The load inertia change detection unit (20) determines the distribution of the load application object in the vehicle according to the fifth data acquired by the load change detection unit (19) within the initialization time period.

5. The variable stiffness leaf spring management system according to claim 4, characterized in that: The load inertia change detection unit (20) predicts and obtains second data based on the load application object and the distribution of the load application object in the vehicle, and the second data is related to the load change of the leaf spring (5) caused by the load during the vehicle driving process.

6. The variable stiffness leaf spring management system according to claim 5, characterized in that: Each stiffness adjustment mode in the mode conversion determination condition corresponds to a different feature set, and the stiffness adjustment mode analysis module (16) determines at least one stiffness adjustment mode by processing the first to fourth data to extract the feature set.

7. The variable stiffness leaf spring management system according to claim 6, characterized in that: The load inertia change detection unit (20) can establish a predictive correlation relationship between independent variable parameters and dependent variable parameters under different driving conditions based on historical vehicle data in the cloud server.

8. The variable stiffness leaf spring management system according to claim 7, characterized in that: The stiffness adjustment mode analysis module (16) processes the first data, the third data and the fourth data related to the driving condition based on the predicted correlation relationship, and can adjust and obtain the predicted second data corresponding to the predicted correlation relationship.

9. The variable stiffness leaf spring management system according to claim 8, characterized in that: The several characteristics include the first to ninth characteristics: emergency braking, full load or heavy load, high-speed driving, bumps, deep potholes, potholes, single-sided wheels off the ground, curves, and flat roads.

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