An electric vehicle with quick-release battery structure
By using a quick-release battery structure with an installation mechanism, positioning, and impact-resistant mechanism, the problems of inconvenient battery removal and easy damage in electric bicycles are solved, achieving stable battery installation and safe use.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- TIANJIN JINSHANG ELECTRIC VEHICLE CO LTD
- Filing Date
- 2025-04-23
- Publication Date
- 2026-06-05
AI Technical Summary
The batteries in existing electric bicycles are not easy to remove and are easily damaged by external impacts and displacement, resulting in poor safety.
It adopts a quick-release battery structure, including an installation mechanism, a positioning mechanism, and an anti-impact mechanism. It uses built-in installation and achieves stable fixation and buffer protection of the battery through positioning bolts and buffer components.
It enables quick battery installation and removal, facilitates maintenance, prevents the battery from shifting or falling off during riding, and improves installation stability and usage safety.
Smart Images

Figure CN224324093U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electric bicycle technology, and in particular to an electric bicycle with a quick-release battery structure. Background Technology
[0002] In existing technology, an electric bicycle refers to a mechatronic personal transportation tool that uses a battery as auxiliary power and is based on a regular bicycle, equipped with a motor, controller, battery, throttle, brake levers, and a display system. Electric bicycles only became widely popular and entered countless households at the beginning of this century. They are now considered an energy-saving and environmentally friendly mode of transportation. Compared to four-wheeled cars and bicycles, two-wheeled electric bicycles have advantages such as lower price, lower operating costs, convenient parking, less effort, and no traffic congestion restrictions, making them very popular in cities. The frame and battery are indispensable parts of an electric bicycle. Currently, most electric bicycle batteries are fixedly installed in the lower part of the frame or in a storage box under the seat. The batteries are not easily removable and often need to be moved with the vehicle to a suitable location for charging. This makes it inconvenient for users to disassemble and maintain the battery, and the manufacturing and installation process is relatively troublesome. Furthermore, electric bicycles with removable batteries also have problems, such as the battery being easily damaged by impacts and collisions due to the low positioning of the battery removal point.
[0003] Chinese utility model patent application number 202123190436.6 discloses an electric bicycle with a removable battery, including a central support, a rear support fixedly connected to the left side of the central support, a rear wheel movably connected to the left side of the rear support, a main frame fixedly connected to the top of the central support, a seat fixedly connected to the top of the main frame, a diagonal bar fixedly connected to the right side of the central support, a battery module fixedly mounted on the top of the diagonal bar, a front support movably connected to the right side of the diagonal bar, and a front wheel movably connected to the bottom of the front support. However, the battery module in this removable electric bicycle uses an external mounting structure, which is susceptible to external impacts and collisions during operation, causing battery damage and poor safety. Furthermore, its tilted mounting on a single diagonal beam of the electric bicycle, due to the weight of the battery itself, makes it prone to displacement or even detachment during riding, resulting in poor installation stability of the battery module. Utility Model Content
[0004] The purpose of this invention is to provide an electric vehicle with a quick-release battery structure.
[0005] To achieve the above objectives, the technical solution proposed by this utility model is as follows:
[0006] An electric vehicle with a quick-release battery structure includes a frame and a battery body. The battery body is mounted on the lower inner side of the frame. The vehicle also includes a mounting mechanism for forming a semi-open mounting structure, a positioning mechanism for forming a quick-release positioning structure, and an anti-impact mechanism for forming a buffer-type protective structure. The mounting mechanism is arranged on the lower part of the frame, the positioning mechanism is configured on the upper part of the mounting mechanism corresponding to the battery body, and the anti-impact mechanism is mounted on the lower part of the mounting mechanism.
[0007] The mounting mechanism includes a mounting frame, a mounting base plate, and mounting baffles. The mounting frame is located at the lower part of the vehicle frame and is fixedly connected to the vehicle frame. An installation gap is left between the inner side of the mounting frame and the vehicle frame. The mounting base plate is located at the lower inner side of the mounting frame and is fixedly connected to the mounting frame. There are two sets of mounting baffles, which are symmetrically arranged on both sides of the lower part of the mounting frame and fixedly connected to the mounting frame. The battery body is arranged at the upper end of the mounting base plate and located between the two sets of mounting baffles.
[0008] It also includes a mounting base block, which is disposed on the lower part of the side of the vehicle frame near the mounting frame and is fixedly connected to the vehicle frame. The battery body is fixedly connected to the mounting base block by mounting screws.
[0009] The positioning mechanism includes a positioning bracket, a positioning baffle, and a positioning bolt. The positioning bracket is located on the upper part of one end of the mounting frame and is fixedly connected to the mounting frame. The positioning baffle is located on the side of the positioning bracket away from the mounting frame and is fixedly connected to the positioning bracket. The positioning bolt is located at the connection between the positioning baffle and the positioning bracket and passes through the positioning baffle and is threadedly connected to the positioning bracket. The positioning baffle is fixedly connected to the positioning bracket by the positioning bolt. The positioning baffle is located on the upper outer side of the battery body and fits against the side of the battery body.
[0010] The shock-resistant mechanism includes an shock-resistant base block, a shock-resistant baffle, and a buffer assembly. The shock-resistant base block is disposed on the outside of the mounting baffle and is fixedly connected to the mounting baffle by bolts. The shock-resistant baffle is disposed on the upper end of the shock-resistant base block and is fixedly connected to the shock-resistant base block. The buffer assembly is disposed on the upper inner side of the shock-resistant baffle and is located between the shock-resistant baffle and the battery body.
[0011] The buffer assembly includes a buffer base block, a buffer spring, a buffer top block, and a buffer pad. The buffer base block is disposed on the upper inner side of the impact baffle and is fixedly connected to the impact baffle. The interior of the buffer base block is configured as a hollow cavity structure. The buffer spring is disposed within the hollow cavity structure of the buffer base block and one end of the spring is fixedly connected to the buffer base block. The buffer top block is disposed on the side of the buffer base block away from the impact baffle, corresponding to the buffer spring, and is embedded and snapped into the buffer base block. A portion of the buffer top block protrudes from the buffer base block, and the portion of the buffer top block connected to the buffer base block abuts against the buffer spring. The buffer pad is disposed at the end of the buffer top block that protrudes from the buffer base block and is fixedly connected to the buffer top block.
[0012] The positioning mechanism and the shock-resistant mechanism are each provided in two sets, and the two sets of positioning mechanisms and the two sets of shock-resistant mechanisms are symmetrically arranged on both sides of the battery body.
[0013] The frame has a front end and a rear end, with a front wheel at the bottom and a control handle at the top corresponding to the front wheel. The rear wheel is located at the bottom.
[0014] It also includes a seat, which is disposed on the upper part of the frame and fixedly connected to the frame, and mudguards are provided at the front and rear ends of the vehicle for the front and rear wheels, respectively.
[0015] It also includes a shock absorption mechanism, which includes a shock absorption hydraulic rod and a shock absorption spring. The shock absorption hydraulic rod is mounted between the frame and the seat corresponding to the rear wheel. The shock absorption spring is fitted on the outside of the shock absorption hydraulic rod. The shock absorption spring and the shock absorption hydraulic rod together constitute a shock absorber structure.
[0016] The beneficial effects of this utility model are:
[0017] It features a mounting mechanism and a positioning mechanism working together, employing a built-in mounting structure to prevent the battery body from shifting or falling off during riding, ensuring the installation stability of the battery module. Furthermore, the battery body can be quickly disassembled and installed for easy inspection and maintenance. It also has an anti-impact mechanism that acts as a protective structure on the side of the battery body, providing cushioning protection and preventing damage to the battery due to external impacts, thus ensuring strong safety in use. Attached Figure Description
[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0019] Figure 2 This is a schematic diagram showing the cooperation between the installation mechanism of this utility model and the vehicle frame;
[0020] Figure 3 This is a schematic diagram of the impact-resistant mechanism of this utility model;
[0021] Figure 4 This is a cross-sectional view of the buffer component of this utility model.
[0022] In the diagram: 1. Frame; 2. Battery body; 3. Mounting frame; 4. Mounting base plate; 5. Mounting baffle; 6. Mounting base block; 7. Positioning bracket; 8. Positioning baffle; 9. Positioning bolt; 10. Impact-resistant base block; 11. Impact-resistant baffle; 12. Buffer base block; 13. Buffer spring; 14. Buffer top block; 15. Buffer pad; 16. Front wheel; 17. Control handle; 18. Rear wheel; 19. Seat; 20. Mudguard; 21. Shock-absorbing hydraulic rod; 22. Shock-absorbing spring. Detailed Implementation
[0023] The present invention will now be described in further detail with reference to the accompanying drawings.
[0024] An electric vehicle with a quick-release battery structure includes a frame 1 and a battery body 2. The battery body 2 is mounted on the lower inner side of the frame 1. The vehicle also includes a mounting mechanism for forming a semi-open mounting structure, a positioning mechanism for forming a quick-release positioning structure, and an impact-resistant mechanism for forming a buffer-type protective structure. The mounting mechanism is located at the lower part of the frame 1, the positioning mechanism is positioned above the mounting mechanism corresponding to the battery body 2, and the impact-resistant mechanism is mounted at the lower part of the mounting mechanism. A schematic diagram of the overall structure of this invention is shown below. Figure 1 As shown.
[0025] The mounting mechanism includes a mounting frame 3, a mounting base plate 4, and mounting baffles 5. The mounting frame 3 is located at the lower part of the vehicle frame 1 and is fixedly connected to the vehicle frame 1. An installation gap is left between the inner side of the mounting frame 3 and the vehicle frame 1. The mounting base plate 4 is located at the lower inner side of the mounting frame 3 and is fixedly connected to the mounting frame 3. Two sets of mounting baffles 5 are symmetrically arranged on both sides of the lower part of the mounting frame 3 and are fixedly connected to the mounting frame 3. The battery body 2 is arranged on the upper end of the mounting base plate 4 and between the two sets of mounting baffles 5. The mounting mechanism, through the cooperation of the mounting frame 3, the mounting base plate 4, and the mounting baffles 5, forms a semi-open mounting structure at the lower part of the vehicle frame 1, thereby meeting the installation requirements of the battery body 2. The mounting frame 3 provides installation support for the mounting base plate 4 and the mounting baffles 5. The mounting base plate 4 serves as a support structure at the bottom of the mounting frame 3, thereby providing installation support for the battery body 2. The mounting baffles 5 serve as baffle structures on the sides of the mounting frame 3, thereby improving the installation stability of the battery body 2. A schematic diagram of the mounting mechanism and its cooperation with the vehicle frame 1 is shown below. Figure 2 As shown.
[0026] It also includes a mounting base 6, which is located on the lower part of the side of the frame 1 near the mounting frame 3 and is fixedly connected to the frame 1. The battery body 2 is fixedly connected to the mounting base 6 by mounting screws. The mounting base 6 is used as a fixing structure inside the mounting frame 3 to cooperate with the positioning mechanism to fix the battery body 2.
[0027] The positioning mechanism includes a positioning bracket 7, a positioning baffle 8, and a positioning bolt 9. The positioning bracket 7 is located on the upper part of one end of the mounting frame 3 and is fixedly connected to the mounting frame 3. The positioning baffle 8 is located on the side of the positioning bracket 7 away from the mounting frame 3 and is fixedly connected to the positioning bracket 7. The positioning bolt 9 is located at the connection between the positioning baffle 8 and the positioning bracket 7 and passes through the positioning baffle 8, threadedly connecting to the positioning bracket 7. The positioning baffle 8 is fixedly connected to the positioning bracket 7 by the positioning bolt 9. The positioning baffle 8 is located on the upper outer side of the battery body 2 and is fitted against the side of the battery body 2. The positioning mechanism, through the cooperation of positioning bracket 7, positioning baffle 8, and positioning bolt 9, positions the battery body 2 to meet the needs of quick assembly and disassembly of the battery body 2. The positioning bracket 7 provides installation support for the positioning baffle 8, the positioning baffle 8 positions the battery body 2 to ensure the installation stability of the battery body 2, and the positioning bolt 9 connects the positioning baffle 8 to the positioning bracket 7. When it is necessary to assemble or disassemble the battery body 2, the positioning bolt 9 can be rotated to remove the positioning baffle 8 from the positioning bracket 7, and then the battery body 2 can be taken out from the inside of the mounting mechanism.
[0028] The impact-resistant mechanism includes an impact-resistant base block 10, an impact-resistant baffle 11, and a buffer assembly. The impact-resistant base block 10 is disposed on the outer side of the mounting baffle 5 and is fixedly connected to the mounting baffle 5 by bolts. The impact-resistant baffle 11 is disposed on the upper end of the impact-resistant base block 10 and is fixedly connected to the impact-resistant base block 10. The buffer assembly is disposed on the upper inner side of the impact-resistant baffle 11 and is located between the impact-resistant baffle 11 and the battery body 2. The impact-resistant mechanism, through the cooperation of the impact-resistant base block 10, the impact-resistant baffle 11, and the buffer assembly, constitutes an impact-resistant structure on the side of the battery body 2. The impact-resistant base block 10 provides mounting support for the impact-resistant baffle 11 and enables a detachable mounting connection between the impact-resistant baffle 11 and the mounting baffle 5 under the action of bolts. The impact-resistant baffle 11 provides mounting support for the buffer assembly. The buffer assembly provides elastic support for the battery body 2 under the action of the impact-resistant baffle 11 to constitute an impact-resistant structure on the side of the battery body 2. The schematic diagram of the impact-resistant mechanism of this utility model is shown below. Figure 3 As shown.
[0029] The buffer assembly includes a buffer base block 12, a buffer spring 13, a buffer top block 14, and a buffer pad 15. The buffer base block 12 is disposed on the upper inner side of the impact baffle 11 and is fixedly connected to the impact baffle 11. The interior of the buffer base block 12 is configured as a hollow cavity structure. The buffer spring 13 is disposed within the hollow cavity structure of the buffer base block 12, and one end of the spring 13 is fixedly connected to the buffer base block 12. The buffer top block 14 is disposed on the side of the buffer base block 12 away from the impact baffle 11, corresponding to the buffer spring 13, and is embedded and snapped into the buffer base block 12. A portion of the buffer top block 14 protrudes from the buffer base block 12, and the portion of the buffer top block 14 connected to the buffer base block 12 abuts against the buffer spring 13. The buffer pad 15 is disposed at the end of the buffer top block 14 that protrudes from the buffer base block 12 and abuts against the buffer spring 13. Block 14 is fixedly connected. The buffer assembly, through the cooperation of buffer base block 12, buffer spring 13, buffer top block 14, and buffer pad 15, provides elastic support for the battery body 2 under the action of the impact baffle 11. Buffer base block 12 provides mounting support for buffer spring 13 and buffer top block 14. Buffer spring 13 provides elastic support for buffer top block 14. Buffer top block 14 provides mounting support for buffer pad 15 and, under the action of buffer spring 13, elastically connects to the side of the battery body 2 through buffer pad 15. Buffer pad 15 serves as a protective structure on buffer top block 14 to prevent rigid collision between buffer top block 14 and battery body 2, thus avoiding damage to the battery body 2. A cross-sectional view of the buffer assembly of this utility model is shown below. Figure 4 As shown.
[0030] The positioning mechanism and the impact-resistant mechanism are provided in two sets. The two sets of positioning mechanisms and the two sets of impact-resistant mechanisms are symmetrically arranged on both sides of the battery body 2. The two sets of positioning mechanisms and the two sets of impact-resistant mechanisms together form the limiting structure of the upper and lower parts of both sides of the battery body 2 to ensure the installation stability of the battery body 2.
[0031] The frame 1 has a front end and a rear end, respectively. The front end has a front wheel 16 at the bottom and a control handle 17 at the top corresponding to the front wheel 16. The rear end has a rear wheel 18 at the bottom. The frame 1 has a drive motor at the bottom corresponding to the rear wheel 18. The output end of the drive motor is connected to the rear wheel 18 via a chain and a sprocket. The frame 1 is mounted on the ground via the front wheel 16 and the rear wheel 18. The control handle 17 is used to control the orientation of the front wheel 16 to control the forward direction of the electric vehicle.
[0032] It also includes a seat 19, which is located on the upper part of the frame 1 and fixedly connected to the frame 1. Mudguards 20 are provided at the front end and the rear end of the vehicle for the front wheel 16 and the rear wheel 18. The seat 19 is used to meet the riding needs of the driver, and the mudguards 20 are used to protect the front wheel 16 and the rear wheel 18 from mud during the journey.
[0033] It also includes a shock absorption mechanism, which includes a shock absorption hydraulic rod 21 and a shock absorption spring 22. The shock absorption hydraulic rod 21 is mounted between the frame 1 and the seat 19 corresponding to the rear wheel 18. The shock absorption spring 22 is fitted on the outside of the shock absorption hydraulic rod 21. The shock absorption spring 22 and the shock absorption hydraulic rod 21 together form a shock absorber structure. The shock absorption mechanism, through the cooperation of the shock absorption hydraulic rod 21 and the shock absorption spring 22, forms a shock absorber structure to reduce vibration during travel and improve the passability and comfort of the electric vehicle in complex road conditions.
[0034] In this technical solution, the shock absorber structure can be the existing electric vehicle shock absorber structure, and other existing shock absorbers with shock absorption functions can be used to replace it. The connection method and working principle are common knowledge, so they will not be described in detail here.
[0035] Working principle:
[0036] In use, place the battery body 2 on the mounting base plate 4, positioning it between the two sets of mounting baffles 5. Connect the battery body 2 to the mounting base block 6 with screws. Then, install the positioning baffle 8 on the positioning bracket 7 using positioning bolts 9, ensuring the positioning baffle 8 fits against the upper part of the battery body 2, thus positioning the upper part of the battery body 2. Next, connect the impact-resistant base block 10 to the mounting baffle 5 with bolts, allowing the buffer assembly to provide elastic cushioning support for the lower part of the battery body 2 under the action of the impact-resistant baffle 11. This completes the installation of the battery body 2. During riding... If the battery body 2 is subjected to an impact from the side, the buffer assembly can mitigate the impact through the buffer base 12, buffer spring 13, buffer top block 14 and buffer pad 15, thus effectively protecting the battery body 2. When it is necessary to remove the battery body 2 from the mounting mechanism, rotate the positioning bolt 9 to remove the positioning baffle 8 from the positioning bracket 7, loosen the bolts connecting the impact base 10 and the mounting baffle 5, so that the impact baffle 11 rotates a certain angle relative to the mounting frame 3, and remove the screws connecting the battery body 2 and the mounting base 6, then the battery body 2 can be removed from the mounting mechanism.
[0037] The beneficial effects of this utility model are that it has an installation mechanism and a positioning mechanism working together, and adopts a built-in installation structure to prevent the battery body from shifting or falling off during riding, ensuring the installation stability of the battery module. In addition, the battery body can be quickly disassembled and installed, which is convenient for inspection and maintenance. It has an anti-impact mechanism, which can serve as a protective structure on the side of the battery body to buffer and protect the battery body from damage caused by external impacts, thus ensuring strong safety in use.
[0038] The above description details one embodiment of the present utility model, but it is merely a preferred embodiment and should not be construed as limiting the scope of the present utility model. All equivalent variations and improvements made within the scope of the present utility model application should still fall within the patent coverage of the present utility model.
Claims
1. An electric vehicle with a quick-release battery structure, comprising a frame (1) and a battery body (2), wherein the battery body (2) is mounted on the lower inner side of the frame (1), characterized in that, It also includes an installation mechanism for forming a semi-open installation structure, a positioning mechanism for forming a quick-release positioning structure, and an anti-impact mechanism for forming a buffer protection structure. The installation mechanism is arranged at the lower part of the frame (1), the positioning mechanism is arranged at the upper part of the installation mechanism corresponding to the battery body (2), and the anti-impact mechanism is assembled at the lower part of the installation mechanism.
2. An electric vehicle with a quick-release battery structure as described in claim 1, characterized in that, The mounting mechanism includes a mounting frame (3), a mounting base plate (4), and mounting baffles (5). The mounting frame (3) is located at the lower part of the vehicle frame (1) and is fixedly connected to the vehicle frame (1). There is an installation gap between the inner side of the mounting frame (3) and the vehicle frame (1). The mounting base plate (4) is located at the lower inner side of the mounting frame (3) and is fixedly connected to the mounting frame (3). There are two sets of mounting baffles (5). The two sets of mounting baffles (5) are symmetrically arranged on both sides of the lower part of the mounting frame (3) and are fixedly connected to the mounting frame (3). The battery body (2) is arranged at the upper end of the mounting base plate (4) and is located between the two sets of mounting baffles (5).
3. An electric vehicle with a quick-release battery structure as described in claim 2, characterized in that, It also includes a mounting base (6), which is disposed on the lower part of the side of the vehicle frame (1) near the mounting frame (3) and is fixedly connected to the vehicle frame (1). The battery body (2) is fixedly connected to the mounting base (6) by mounting screws.
4. An electric vehicle with a quick-release battery structure as described in claim 3, characterized in that, The positioning mechanism includes a positioning bracket (7), a positioning baffle (8), and a positioning bolt (9). The positioning bracket (7) is located on the upper part of one end of the mounting frame (3) and is fixedly connected to the mounting frame (3). The positioning baffle (8) is located on the side of the positioning bracket (7) away from the mounting frame (3) and is fixedly connected to the positioning bracket (7). The positioning bolt (9) is located at the connection between the positioning baffle (8) and the positioning bracket (7) and is threaded through the positioning baffle (8) and the positioning bracket (7). The positioning baffle (8) is fixedly connected to the positioning bracket (7) by the positioning bolt (9). The positioning baffle (8) is located on the upper outer side of the battery body (2) and is fitted against the side of the battery body (2).
5. An electric vehicle with a quick-release battery structure as described in claim 4, characterized in that, The shock-resistant mechanism includes an shock-resistant base block (10), an shock-resistant baffle (11), and a buffer assembly. The shock-resistant base block (10) is disposed on the outside of the mounting baffle (5) and is fixedly connected to the mounting baffle (5) by bolts. The shock-resistant baffle (11) is disposed on the upper end of the shock-resistant base block (10) and is fixedly connected to the shock-resistant base block (10). The buffer assembly is disposed on the upper inner side of the shock-resistant baffle (11) and is located between the shock-resistant baffle (11) and the battery body (2).
6. An electric vehicle with a quick-release battery structure as described in claim 5, characterized in that, The buffer assembly includes a buffer base block (12), a buffer spring (13), a buffer top block (14), and a buffer pad (15). The buffer base block (12) is disposed on the upper inner side of the impact baffle (11) and is fixedly connected to the impact baffle (11). The interior of the buffer base block (12) is configured as a hollow cavity structure. The buffer spring (13) is disposed within the hollow cavity structure of the buffer base block (12) and one end of it is fixedly connected to the buffer base block (12). The buffer top block (14) is... The buffer spring (13) is located on the side of the buffer base block (12) away from the anti-impact baffle (11) and is embedded and snapped into the buffer base block (12). A portion of the buffer top block (14) protrudes from the buffer base block (12) and the portion connected to the buffer base block (12) abuts against the buffer spring (13). The buffer pad (15) is located at one end of the buffer top block (14) that protrudes from the buffer base block (12) and is fixedly connected to the buffer top block (14).
7. An electric vehicle with a quick-release battery structure as described in claim 6, characterized in that, The positioning mechanism and the shock-resistant mechanism are provided in two sets, and the two sets of positioning mechanism and the two sets of shock-resistant mechanism are symmetrically arranged on both sides of the battery body (2).
8. An electric vehicle with a quick-release battery structure as described in claim 7, characterized in that, The two ends of the frame (1) are the front end and the rear end, respectively. The front end is equipped with a front wheel (16) at the bottom and a control handle (17) is provided on the upper part corresponding to the front wheel (16). The rear end is equipped with a rear wheel (18) at the bottom.
9. An electric vehicle with a quick-release battery structure as described in claim 8, characterized in that, It also includes a seat (19), which is located on the upper part of the frame (1) and fixedly connected to the frame (1). Mudguards (20) are provided at the front end and the rear end of the vehicle for the front wheel (16) and the rear wheel (18).
10. An electric vehicle with a quick-release battery structure as described in claim 9, characterized in that, It also includes a shock-absorbing mechanism, which includes a shock-absorbing hydraulic rod (21) and a shock-absorbing spring (22). The shock-absorbing hydraulic rod (21) is mounted between the frame (1) and the seat (19) corresponding to the rear wheel (18). The shock-absorbing spring (22) is fitted on the outside of the shock-absorbing hydraulic rod (21). The shock-absorbing spring (22) and the shock-absorbing hydraulic rod (21) together constitute a shock absorber structure.