A leaf spring suspension system and vehicle

Abstract

The utility model relates to a kind of steel plate spring suspension system and vehicle, steel plate spring suspension system is connected between the frame assembly and axle assembly of vehicle, including steel plate spring assembly, and lug, the upper end of the lug is hinged with the frame assembly, forms first articulation point, the steel plate spring assembly includes first leaf spring section and second leaf spring section, the length of the first leaf spring section is greater than the length of the second leaf spring section, the end of the first leaf spring section is hinged with the frame assembly, forms second articulation point, the end of the second leaf spring section is hinged with the lower end of the lug, forms third articulation point, the second articulation point is located above the third articulation point.The steel plate spring suspension system designed by the utility model is suitable for low-speed unmanned vehicle, and can effectively suppress the pitching vibration of vehicle.

Description

Technical Field

[0001] This utility model relates to the field of automotive equipment technology, and in particular to a leaf spring suspension system and vehicle. Background Technology

[0002] The suspension system is a critical component of a vehicle, and its performance directly affects driving stability. Leaf spring suspension systems are widely used in various vehicles, such as low-speed autonomous vehicles (e.g., logistics delivery vehicles), due to their simple structure, low manufacturing cost, and high load-bearing capacity. Unlike traditional heavy-duty trucks that use multi-leaf springs, low-speed autonomous vehicles, due to their smaller load capacity, often use single-leaf or a few-leaf springs. While this simplified design reduces system complexity and material consumption, it cannot provide sufficient anti-pitch torque. Furthermore, the smaller wheelbase of low-speed autonomous vehicles amplifies their sensitivity to pitch vibrations—during braking or acceleration, the vehicle's center of gravity shifts more violently, easily causing nose-dive or tail-dive phenomena, affecting handling stability. Therefore, there is an urgent need for an adaptive leaf spring suspension system specifically designed for low-speed autonomous vehicles to effectively suppress vehicle pitch vibrations. Utility Model Content

[0003] To address the aforementioned problems, the purpose of this utility model is to design a leaf spring suspension system and vehicle that can effectively suppress vehicle pitch vibration.

[0004] The objective of this utility model is achieved through the following technical solution: Design a leaf spring suspension system connecting the vehicle frame assembly and axle assembly. The system includes a leaf spring assembly and a hanger. The upper end of the hanger is hinged to the frame assembly, forming a first hinge point. The leaf spring assembly includes a first leaf spring segment and a second leaf spring segment. The length of the first leaf spring segment is greater than the length of the second leaf spring segment. The end of the first leaf spring segment is hinged to the frame assembly, forming a second hinge point. The end of the second leaf spring segment is hinged to the lower end of the hanger, forming a third hinge point. The second hinge point is located above the third hinge point.

[0005] In this design, the first leaf spring segment (the longer segment) is fixed to the frame assembly at the second hinge point, while the second leaf spring segment (the shorter segment) is connected to the third hinge point via a hanger, with the second hinge point positioned above the third hinge point. This vertically asymmetrical layout creates an asymmetrical stiffness distribution. The longer leaf spring segment provides flexible cushioning, absorbing vertical vibrations, while the shorter leaf spring segment enhances rigidity, generating greater anti-pitch moments during acceleration or braking. The hanger, acting as an intermediate hinge point, adds system degrees of freedom, allowing the second leaf spring segment to absorb high-frequency impacts during vibrations. When the vehicle's center of gravity shifts (such as during braking and forward tilting), it can transfer forces to the frame, reducing pitch displacement and thus minimizing nose-dive / tail-dive.

[0006] Furthermore, the horizontal distance between the first hinge point and the second hinge point is greater than the horizontal distance between the third hinge point and the second hinge point.

[0007] In this design, the hanger is tilted and the lower end of the hanger is located in front of the upper end. As a result, during the compression of the leaf spring assembly, the third hinge point of the leaf spring assembly swings backward with the hanger. During the swing of the hanger, the third hinge point of the leaf spring assembly will move backward and downward at the same time. This will increase the height difference between the front and rear ends of the leaf spring and improve the vehicle's anti-dive performance.

[0008] Furthermore, the first leaf spring segment includes a first horizontal root, the second leaf spring segment includes a second horizontal root, the first horizontal root and the second horizontal root are connected to form a horizontal connecting portion, the horizontal connecting portion is parallel to the mounting base surface of the frame assembly, and the axle assembly is connected to the horizontal connecting portion through a locking connector.

[0009] In this design, the leaf spring assembly is installed horizontally, so that the connection points at both ends of the frame assembly and the leaf spring assembly bear the same vertical and horizontal loads. At the same time, it ensures that the leaf spring assembly will not cause the axle assembly to overturn during the compression deformation process, thereby changing the kingpin caster angle and avoiding affecting the vehicle's driving stability.

[0010] Furthermore, the leaf spring assembly also includes a limiting block disposed on the horizontal connecting portion. The limiting block is located on the side of the leaf spring assembly away from the axle assembly, and the limiting block is pressed and attached to the leaf spring assembly by the locking connector.

[0011] In this design, the limiting blocks are mostly made of rubber or polyurethane. They contact the leaf springs under extreme loads (such as bumps or full loads) and provide rigid support, limiting excessive deformation, absorbing impact energy, and protecting critical components, thus significantly improving the safety and durability of the suspension system. Furthermore, the leaf spring is assembled into a single leaf spring.

[0012] In this design, a single-leaf spring with a variable cross-section—thicker in the middle and thinner at both ends—achieves non-linear stiffness variation with load, balancing unloaded comfort with full-load support and significantly reducing the weight of the suspension system. Compared to multi-leaf springs, this weight reduction directly decreases unsprung mass and improves vehicle handling response.

[0013] Furthermore, the leaf spring assembly includes multiple stacked leaf springs, wherein one end of the uppermost leaf spring closest to the frame assembly is hinged to the frame assembly to form a second hinge point, and the other end is hinged to the lower end of the hanger to form a third hinge point.

[0014] In this design, the leaf spring assembly can be made of two or three leaf springs of unequal length but the same width, stacked in an inverted triangular shape, with the top leaf being the longest and the bottom leaf the shortest. The stacked structure of multiple leaves gives the leaf spring a high overall rigidity, enabling it to withstand greater weight.

[0015] Furthermore, the leaf spring assembly also includes a central bolt disposed at the horizontal connection portion, the central bolt passing through multiple leaf springs and pressing them together.

[0016] In this design, the leaf springs are equipped with a central hole, and a central bolt passes through the central hole of multiple leaf springs to fasten the springs together as a whole, preventing the leaf springs from shifting.

[0017] Furthermore, the leaf spring assembly is divided into a first leaf spring segment and a second leaf spring segment with the axis of the central bolt as the dividing line.

[0018] Furthermore, it also includes a shock absorber assembly, one end of which is hinged to the frame assembly and the other end of which is hinged to the axle assembly.

[0019] In this design, the shock absorber assembly works in conjunction with the leaf spring to suppress spring rebound and vibration, thereby improving ride smoothness.

[0020] Based on the same concept, a vehicle is also provided, including the aforementioned leaf spring suspension system.

[0021] Compared with the prior art, the beneficial effects of this utility model are: In this design, the first leaf spring segment (the longer segment) is fixed to the frame assembly at the second hinge point, while the second leaf spring segment (the shorter segment) is connected to the third hinge point via a hanger, with the second hinge point positioned above the third hinge point. This vertically asymmetrical layout creates an asymmetrical stiffness distribution. The longer leaf spring segment provides flexible cushioning, absorbing vertical vibrations, while the shorter leaf spring segment enhances rigidity, generating greater anti-pitch moments during acceleration or braking. The hanger, acting as an intermediate hinge point, adds system degrees of freedom, allowing the second leaf spring segment to absorb high-frequency impacts during vibrations. When the vehicle's center of gravity shifts (such as during braking and forward tilting), it can transfer forces to the frame, reducing pitch displacement and thus minimizing nose-dive / tail-dive. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the connection structure of the leaf spring suspension system, axle assembly, and frame assembly of an existing heavy-duty truck.

[0023] Figure 2 This is a schematic diagram of the structure of a leaf spring assembly for an existing heavy-duty truck.

[0024] Figure 3This is a schematic diagram of the connection structure of a leaf spring suspension system, an axle assembly, and a frame assembly according to an embodiment of the present invention.

[0025] Figure 4 This is a schematic diagram of the structure of a leaf spring assembly according to an embodiment of the present invention.

[0026] Figure 5 This is a schematic diagram of the connection structure of the leaf spring suspension system, axle assembly and frame assembly of a vehicle according to an embodiment of the present invention (the front leaf spring suspension system and the rear leaf spring suspension system are asymmetrically arranged).

[0027] Figure 6 This is a schematic diagram of the symmetrical arrangement of the front leaf spring suspension system and the rear leaf spring suspension system of a vehicle according to an embodiment of the present invention.

[0028] Illustration: 1. Leaf spring suspension system; 1a. Front leaf spring suspension system; 1b. Rear leaf spring suspension system; 11. Leaf spring assembly; 111. First leaf spring segment; 1111. First horizontal root; 112. Second leaf spring segment; 1121. Second horizontal root; 113. Flat connecting part; 114. Locking connecting piece; 115. Second hinge point; 117. Limiting block; 12. Lifting lug; 121. First hinge point; 122. Third hinge point; 13. Shock absorber assembly; 2. Frame assembly; 21. Articulated bracket; 22. Hanger bracket; 3. Axle assembly; 3a. Front axle assembly; 3b. Rear axle assembly; 4. Leaf spring suspension system; 41. Leaf spring assembly; 42. Hanger; 43. Shock absorber assembly; 5. Frame assembly; 51. Articulated bracket; 52. Hanger bracket; 6. Axle assembly. Detailed Implementation

[0029] To facilitate understanding of this invention, a more comprehensive description will be provided below with reference to the accompanying drawings. The drawings illustrate preferred embodiments of the invention. However, this invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0030] like Figure 1As shown, in the existing leaf spring suspension system 4 of a heavy-duty truck, one end of the leaf spring assembly 41 is hinged to the hinge bracket 51 on the frame assembly 5, and the other end is hinged to one end of the hanger 42. The other end of the hanger 42 is hinged to the hanger bracket 52 on the frame assembly 5. The axle assembly 6 is fixed to the leaf spring assembly 41 by U-bolts. The wheel (not shown in the figure) is rigidly connected to the axle assembly 6 and mainly bears the vertical load and transmits the force to the leaf spring assembly 41. At the same time, the leaf spring assembly 41 is composed of multiple leaf springs stacked together, generally more than 3 leaves. There is frictional damping force between the leaves, which can suppress part of the vibration of the axle assembly 6 like a shock absorber assembly. The leaf spring assembly 41 has an arc-shaped design, and the front and rear halves are symmetrical with the center bolt, such as... Figure 2 As shown, the front and rear halves of the leaf spring assembly 41 are both Lf in length. The leaf spring assembly 41, as an elastic element, primarily bears the vertical load transmitted from the axle assembly 6 and buffers the impact of the load transmitted from the axle assembly 6 through its own deformation. During deformation, the horizontal lengths of the front and rear ends of the leaf spring assembly 41 need to change. However, the front end is hinged and fixed to the hinge bracket 51, allowing only rotation around the hinge point and preventing forward and backward movement. The rear end of the leaf spring assembly 41 is hinged to the lower end of the hanger 42, and the upper end of the hanger 42 is hinged to the hanger bracket 52. The hanger 42 can rotate and swing around the hinge point with the hanger bracket 52. Therefore, the rear end of the leaf spring assembly 41 can not only rotate around the hinge point at the lower end of the hanger 42 but also move forward and backward and up and down with the swing of the hanger 42. To improve the vehicle's anti-dive performance, the front end of the leaf spring assembly 41 needs to be designed to be higher than the rear end. However, the leaf spring assembly 41 is a symmetrical design, so the commonly used method is to arrange the leaf spring assembly 41 at an angle, such as... Figure 2 As shown, the leaf spring assembly 41 is arranged at an angle α with the horizontal line.

[0031] For low-speed autonomous vehicles, the leaf spring suspension system 4 of the aforementioned heavy-duty trucks is often directly applied to them. Because low-speed autonomous vehicles have small load capacities, the leaf spring assembly 41 is not used in low-speed autonomous vehicles. Figure 2 The multi-leaf spring assembly shown likely uses three or fewer leaf springs, or even a single leaf spring. This reduces the frictional damping force between the leaves, which is detrimental to the vehicle's pitch vibration. Furthermore, the wheelbase of low-speed unmanned vehicles is smaller than that of heavy-duty vehicles, exacerbating pitch vibration. Additionally, to suppress brake dive, the leaf spring assembly 41 often employs... Figure 2The inclined arrangement shown causes the front bracket of the leaf spring to bear greater vertical and horizontal loads. Furthermore, the compression deformation of the leaf spring causes the axle assembly 6 to flip, altering the kingpin caster angle and affecting vehicle stability. With the lower end of the hanger 42 located behind the upper end, during compression of the leaf spring assembly 41, the rear end of the assembly moves backward and upward with the rearward swing of the hanger 42, reducing the height difference between the front and rear ends of the leaf spring assembly 41 and negatively impacting the vehicle's anti-dive performance. Example 1

[0032] To address the aforementioned issues, this embodiment provides a leaf spring suspension system suitable for low-speed unmanned vehicles to improve their anti-pitch performance, as detailed below.

[0033] like Figure 3 and 4 As shown, this embodiment provides a leaf spring suspension system 1, connected between the vehicle frame assembly 2 and the axle assembly 3. It includes a leaf spring assembly 11 and a hanger 12. The upper end of the hanger 12 is hinged to the frame assembly 2, forming a first hinge point 121. The leaf spring assembly 11 includes a first leaf spring segment 111 and a second leaf spring segment 112. The length of the first leaf spring segment 111 is greater than the length of the second leaf spring segment 112 (Lf1 > Lf2). The end of the first leaf spring segment 111 is hinged to the frame assembly 2, forming a second hinge point 115. The end of the second leaf spring segment 112 is hinged to the lower end of the hanger 12, forming a third hinge point 122. The second hinge point 115 is located above the third hinge point 122. A wheel (not shown in the figure) is rigidly connected to the axle assembly 3, primarily bearing the vertical load and transmitting force to the leaf spring assembly 11. The leaf spring assembly 11, as an elastic element, mainly bears the vertical load transmitted from the axle assembly 3, and buffers the load impact transmitted from the axle assembly 3 through its own deformation.

[0034] In this embodiment, the leaf spring assembly 11 is a single-leaf leaf spring. By employing a variable cross-section design—thicker in the middle and thinner at both ends—the stiffness can change non-linearly with load, balancing unloaded comfort and full-load support, significantly reducing the weight of the suspension system. Compared to multi-leaf springs, the weight is reduced, directly decreasing unsprung mass and improving vehicle handling response.

[0035] It should be noted that the frame assembly 2 includes a hinge bracket 21 and a hanger bracket 22, both of which can be fixed to the frame body by welding or riveting. The upper end of the hanger 12 is hinged to the hanger bracket 22, forming a first hinge point 121. The end of the first leaf spring segment 111 can adopt an upper or lower rolled ear design, and is hinged to the hinge bracket 21, forming a second hinge point 115. The end of the second leaf spring segment 112 can also adopt an upper or lower rolled ear design, and is hinged to the lower end of the hanger 12, forming a third hinge point 122.

[0036] The first leaf spring segment 111 (the longer segment) is fixed to the frame assembly 2 at the second hinge point 115. The second leaf spring segment 112 (the shorter segment) is connected to the third hinge point 122 via a hanger 12, with the second hinge point 115 located above the third hinge point 122. This vertically asymmetrical layout creates an asymmetrical stiffness distribution. The longer leaf spring segment provides flexible cushioning, absorbing vertical vibrations, while the shorter leaf spring segment enhances rigidity, generating greater anti-pitch moment during acceleration or braking. The hanger 12, acting as an intermediate hinge point, adds system degrees of freedom, allowing the second leaf spring segment 112 to absorb high-frequency impacts during vibrations. When the vehicle's center of gravity shifts (such as when it leans forward during braking), it can transfer forces to the frame, reducing pitch angle displacement and thus reducing nose-dive / tail-dive amplitude.

[0037] Furthermore, the horizontal distance between the first hinge point 121 and the second hinge point 115 is greater than the horizontal distance between the third hinge point 122 and the second hinge point 115. That is, in this embodiment, the lug 12 is inclined, and the lower end of the lug 12 is located in front of the upper end. During the deformation process, the horizontal length of the front and rear ends of the leaf spring assembly 11 needs to change. The front end is hinged and fixed to the hinge bracket 21, and can only rotate around the second hinge point 115, and cannot move back and forth. The rear end of the leaf spring assembly 11 is hinged to the lower end of the lug 12, and the upper end of the lug 12 is hinged to the lug bracket 22. Therefore, the third hinge point 122 of the leaf spring assembly 11 swings back with the lug 12. During the swing of the lug 12, it will drive the third hinge point 122 of the leaf spring assembly 11 to move backward and downward at the same time. This can increase the height difference between the front and rear ends of the leaf spring assembly 11, and improve the vehicle's anti-dive performance.

[0038] Furthermore, such as Figure 4As shown, the first leaf spring segment 111 includes a first horizontal root 1111, and the second leaf spring segment 112 includes a second horizontal root 1121. The first horizontal root 1111 and the second horizontal root 1121 are connected to form a horizontal connecting portion 113. The thickness of the horizontal connecting portion 113 is greater than the thickness of other parts of the leaf spring, forming a variable cross-section design. The horizontal connecting portion 113 is parallel to the mounting base surface of the frame assembly 2, and the axle assembly 3 is connected to the horizontal connecting portion 113 through a locking connector 114. Specifically, the horizontal connecting portion 113 is located above the axle assembly 3. The locking connector 114 can be a U-bolt. By fastening with the U-bolt, the leaf spring is connected to the axle assembly 3. When the vehicle is stationary, the U-bolt is not subjected to axial force and mainly bears shear force. The leaf spring assembly 11 is installed horizontally so that the connection points between the frame assembly 2 and the two ends of the leaf spring assembly 11 bear the same vertical and horizontal loads. At the same time, it ensures that the leaf spring assembly 11 will not cause the axle assembly 3 to overturn during the compression deformation process, thereby changing the kingpin caster angle and avoiding affecting the driving stability of the vehicle.

[0039] Furthermore, such as Figure 3 As shown, the leaf spring assembly 11 also includes a limiting block 117 disposed on the horizontal connecting portion 113. The limiting block 117 is located on the side of the leaf spring assembly 11 away from the axle assembly 3, and is pressed and fitted onto the leaf spring assembly 11 by a locking connector 114. The limiting block 117 is mostly made of rubber or polyurethane. When the leaf spring is subjected to extreme loads (such as bumps or full load), it contacts and provides rigid support, which can limit excessive deformation, absorb impact energy, and protect critical components, significantly improving the safety and durability of the suspension system. Furthermore, such as Figure 3 As shown, the leaf spring suspension system 1 also includes a shock absorber assembly 13, one end of which is hinged to the frame assembly 2, and the other end is hinged to the axle assembly 3. The shock absorber assembly 13 works in conjunction with the leaf spring assembly 11 to suppress spring rebound and vibration, thereby improving ride comfort.

[0040] In another embodiment, the leaf spring assembly 11 may be configured as comprising multiple stacked leaf springs, wherein one end of the uppermost leaf spring closest to the frame assembly 2 is hinged to the frame assembly 2, forming a second hinge point 115, and the other end is hinged to the lower end of the lug 12, forming a third hinge point 122. The leaf spring assembly 11 may be composed of two or three leaf springs of unequal lengths but the same width, stacked in an inverted triangular shape, with the uppermost leaf spring being the longest and the lowermost leaf spring the shortest. The stacked structure of multiple leaf springs makes the overall rigidity of the leaf springs greater, enabling them to withstand greater weight. A center bolt is provided at the horizontal connecting part 113, and the leaf springs have center holes. The center bolt passes through the center holes of the multiple leaf springs, securing each spring into a whole and preventing the leaf springs from shifting. In addition, in this embodiment, the leaf spring assembly 11 is divided into a first leaf spring segment 111 and a second leaf spring segment 112 with the axis of the center bolt as the dividing line. Example 2

[0041] like Figure 5 and 6 As shown, this embodiment also provides a vehicle, a low-speed unmanned vehicle, including the aforementioned leaf spring suspension system 1. Specifically, the vehicle includes a frame assembly 2, a front axle assembly 3a, and a rear axle assembly 3b. The aforementioned leaf spring suspension system 1 is respectively installed at the wheel ends of the front axle assembly 3a and the rear axle assembly 3b, namely the front leaf spring suspension system 1a and the rear leaf spring suspension system 1b, meaning the vehicle is equipped with four sets of leaf spring suspension systems 1. Figure 5 and 6 As shown, viewed from the side of the vehicle, the front leaf spring suspension system 1a and the rear leaf spring suspension system 1b can be symmetrically or asymmetrically arranged depending on the actual situation.

[0042] In the description of this utility model, it should be understood that terms such as "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0043] Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, the inclusion of "first," "second," etc., in a feature may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0044] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A leaf spring suspension system, connected between the vehicle frame assembly and the axle assembly, characterized in that, The system includes a leaf spring assembly and a hanger. The upper end of the hanger is hinged to the frame assembly to form a first hinge point. The leaf spring assembly includes a first leaf spring segment and a second leaf spring segment. The length of the first leaf spring segment is greater than the length of the second leaf spring segment. The end of the first leaf spring segment is hinged to the frame assembly to form a second hinge point. The end of the second leaf spring segment is hinged to the lower end of the hanger to form a third hinge point. The second hinge point is located above the third hinge point.

2. The leaf spring suspension system according to claim 1, characterized in that, The horizontal distance between the first hinge point and the second hinge point is greater than the horizontal distance between the third hinge point and the second hinge point.

3. The leaf spring suspension system according to claim 1, characterized in that, The first leaf spring segment includes a first horizontal root, the second leaf spring segment includes a second horizontal root, the first horizontal root and the second horizontal root are connected to form a horizontal connecting part, the horizontal connecting part is parallel to the mounting base surface of the frame assembly, and the axle assembly is connected to the horizontal connecting part through a locking connector.

4. The leaf spring suspension system according to claim 3, characterized in that, The leaf spring assembly also includes a limiting block disposed on the horizontal connecting portion. The limiting block is located on the side of the leaf spring assembly away from the axle assembly, and the limiting block is pressed and attached to the leaf spring assembly by the locking connector.

5. The leaf spring suspension system according to claim 3, characterized in that, The leaf spring assembly is a single-piece leaf spring.

6. The leaf spring suspension system according to claim 3, characterized in that, The leaf spring assembly includes multiple stacked leaf springs, wherein one end of the uppermost leaf spring closest to the frame assembly is hinged to the frame assembly to form a second hinge point, and the other end is hinged to the lower end of the lug to form a third hinge point.

7. The leaf spring suspension system according to claim 6, characterized in that, The leaf spring assembly also includes a central bolt disposed at the horizontal connection portion, the central bolt passing through multiple leaf springs and pressing them together.

8. The leaf spring suspension system according to claim 7, characterized in that, The leaf spring assembly is divided into a first leaf spring section and a second leaf spring section, with the axis of the central bolt as the dividing line.

9. The leaf spring suspension system according to claim 1, characterized in that, It also includes a shock absorber assembly, one end of which is hinged to the frame assembly and the other end of which is hinged to the axle assembly.

10. A vehicle, characterized in that, Includes the leaf spring suspension system as described in any one of claims 1 to 9.

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