Rear derailleur connection structure and electric vehicle

Abstract

The utility model provides a kind of rear flat fork connecting structure and electric vehicle, it is related to electric vehicle mounting support technical field, this kind of rear flat fork connecting structure includes through core shaft, lug assembly and bridge type connecting plate assembly, lug assembly is fixedly arranged in the both sides of rear end of vehicle frame, bridge type connecting plate assembly is arranged between the mounting seat of rear flat fork, through core shaft passes through lug assembly, mounting seat and bridge type connecting plate assembly simultaneously, the utility model strengthens the connecting strength of rear flat fork and vehicle frame by bridge type connecting plate assembly, the driving / braking force generated when accelerating or braking, via rear wheel-rear flat fork-pivot bushing-lug assembly and bridge type connecting plate assembly-vehicle frame, form complete and short path's load closed loop, overall structure closed loop, easily engineering implementation, high torsional stiffness, installation precision is good, load path optimization, with realizability, it can also realize the adaptation to wheel hub motor drive platform, improve the whole vehicle stability and control precision.

Description

Technical Field

[0001] This utility model relates to the field of electric vehicle mounting bracket technology, and in particular to a rear flat fork connection structure and an electric vehicle. Background Technology

[0002] With increasing urban traffic congestion, two-wheeled vehicles, less affected by traffic conditions, are gradually becoming the preferred choice for short-distance travel. Among various types of two-wheeled vehicles, electric vehicles are particularly favored by the market due to their green and environmentally friendly characteristics. The rear swingarm, as a key component connecting the rear axle to the frame, directly affects the handling and safety of the entire electric vehicle.

[0003] Traditional frame and swingarm connections often use a single-point hinge structure, which has several drawbacks in practical use: First, the single-point connection leads to insufficient local rigidity, making the swingarm prone to shifting under bending and emergency braking conditions. Second, the unique structural layout of electric vehicles (such as the battery pack and hub motor located under the footrest) shifts the vehicle's center of gravity forward, increasing the unsprung mass of the rear wheel. Furthermore, the lack of a chain traction path found in traditional gasoline motorcycles means that driving and braking forces are transmitted entirely through the swingarm pivot point to the main frame, placing higher demands on the strength, rigidity, and dynamic consistency of the connection points. In addition, traditional connection structures are prone to stress concentration over long-term use, and the pivot point is susceptible to fatigue damage, leading to problems such as vibration, deformation, and response delays during riding, severely impacting the riding experience and safety.

[0004] To address the aforementioned issues, existing technologies urgently need improvement. Summary of the Invention

[0005] In view of this, one of the objectives of this utility model is to provide a rear swingarm connection structure to solve the defects of the prior art where the rear swingarm is connected to the frame by a single-point hinge, which has insufficient local rigidity, causing the rear swingarm to deviate under bending and extreme braking conditions, easily resulting in shaking, deformation and response delay, as well as the structural defects of stress concentration and easy fatigue of the swingarm pivot point.

[0006] The second objective of this utility model is to provide an electric vehicle with a rear flat fork connection structure.

[0007] To achieve one of the above objectives, this utility model provides a rear swingarm connection structure for connecting the rear swingarm and the frame, including a through-type spindle, a lug assembly, and a bridge-type connecting plate assembly. The lug assembly is fixedly disposed on both sides of the rear end of the frame, and the bridge-type connecting plate assembly is disposed between the mounting seats of the rear swingarm. The through-type spindle passes through the lug assembly, the mounting seats, and the bridge-type connecting plate assembly.

[0008] Optionally, the lug assembly includes a left lug and a right lug, both ends of which are connected to the vehicle frame.

[0009] Optionally, the bridge-type connecting plate assembly includes a left bridge-type connecting plate and a right bridge-type connecting plate connected to the vehicle frame, and at least one set of horizontal tubes is provided between the left bridge-type connecting plate and the right bridge-type connecting plate, the horizontal tubes passing through both the left bridge-type connecting plate and the right bridge-type connecting plate.

[0010] Optionally, the horizontal tube includes a first horizontal tube and a second horizontal tube, with both ends of the first horizontal tube and the second horizontal tube simultaneously installed on the left bridge connecting plate and the right bridge connecting plate, and the through-type mandrel passing through the first horizontal tube.

[0011] Optionally, both the left bridge connecting plate and the right bridge connecting plate are configured as angular plate structures, each including a first plate and a second plate. The first plate and the second plate are integrally formed. The first plate is perpendicular to the connecting tube of the frame, and the second plate is parallel to the connecting tube of the frame. The second plate is fixedly mounted on the connecting tube of the frame.

[0012] Optionally, the first plate and / or the second plate are provided with clearance space adapted to the connecting tube of the frame.

[0013] Optionally, the lower ends of the left bridge connecting plate and the right bridge connecting plate are provided with mounting holes for installing the central support.

[0014] Optionally, the rear swingarm is an integrally welded rear swingarm assembly, with the front end being the mounting base and the rear end being the hub motor mounting position.

[0015] To achieve the second objective mentioned above, this utility model provides an electric vehicle, including any of the aforementioned rear swingarm connection structures, and further including a rear swingarm and a frame, wherein the rear swingarm connection structure is used to connect the rear swingarm, the frame, and the central support frame.

[0016] The rear flat fork connection structure provided by this utility model has the following technical advantages: This rear swingarm connection structure, used to connect the rear swingarm and the frame, includes a through-type spindle, a lug assembly, and a bridge-type connecting plate assembly. The lug assembly is fixedly installed on both sides of the rear end of the frame, and the bridge-type connecting plate assembly is located between the mounting seats of the rear swingarm. The through-type spindle passes through the lug assembly, the mounting seat, and the bridge-type connecting plate assembly. This invention strengthens the connection between the rear swingarm and the frame through the bridge-type connecting plate assembly. That is, the driving / braking force generated during acceleration or braking forms a complete and short-path load closed loop via the rear wheel—rear swingarm—pivot bushing—lug assembly and bridge-type connecting plate assembly—frame. The overall structure is closed-loop, easy to implement in engineering, has high torsional stiffness, good installation accuracy, and optimized load path. It is feasible and can also be adapted to hub motor drive platforms, improving the stability and handling accuracy of the vehicle. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a three-dimensional structural diagram of the rear flat fork connection structure of this utility model; Figure 2 yes Figure 1 Enlarged structural diagram at point A; Figure 3 yes Figure 1 Front view of the rear horizontal fork connection structure; Figure 4 yes Figure 1 Top view of the rear horizontal fork connection structure; Figure 5 yes Figure 1 A schematic diagram of the rear swingarm connection structure; Figure 6 yes Figure 1 A schematic diagram of the bridge-type connecting plate assembly of the mid-rear horizontal fork connection structure; Figure 7 yes Figure 1 A schematic diagram of the through-type mandrel of the bridge-type connecting plate assembly; Figure 8 yes Figure 1 Stress analysis diagram of the mid-rear horizontal fork connection structure.

[0019] in, Figures 1-8 : 1. Rear swingarm; 11. Mounting bracket; 12. Mounting position for hub motor; 2. Frame; 3. Left lug; 31. Left mounting position; 32. Left clearance space; 4. Right lug; 41. Right mounting position; 42. Right clearance space; 5. Bridge plate assembly; 51. Left bridge plate; 511. First plate; 512. Second plate; 52. Right bridge plate; 53. First cross tube; 54. Second cross tube; 55. Center stand mounting hole; 56. Clearance space; 6. Through-type spindle. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be described in detail below. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other implementation methods obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0021] In existing technologies, two-wheeled vehicles, especially electric vehicles, are becoming increasingly popular due to their convenience and environmental friendliness. However, the traditional connection structure between the rear swingarm 1 and the frame 2 suffers from problems such as insufficient rigidity and stress concentration. The single-point hinge design is prone to rear swingarm offset during bending or emergency braking, and uneven weight distribution exacerbates fatigue damage at the connection points. Long-term use can easily lead to vibration, deformation, and response delay. For example, in scenarios with frequent starts and stops or high-speed cornering, the traditional structure struggles to effectively distribute the concentrated loads along the driving and braking force transmission paths.

[0022] To overcome the shortcomings of existing technologies, the following section, in conjunction with specific appendices, provides further details. Figure 1-8 The rear flat fork connection structure of this utility model is described in detail.

[0023] This utility model details a basic implementation scheme for a rear swingarm connection structure. The scheme aims to solve the problems of insufficient connection rigidity and stress concentration in existing technologies by introducing an independent reinforcing component and tightly integrating it with the frame 2 and the rear swingarm 1 through a shared through-type spindle, thereby constructing a high-rigidity pivot connection system.

[0024] like Figure 1-7As shown, the rear swingarm connection structure is used to pivotally connect a rear swingarm 1 to the vehicle frame 2. In the overall structure of the electric vehicle, the frame 2 is the basic skeleton that bears all components, and is usually welded or cast from high-strength steel tubing or aluminum alloy profiles. The rear swingarm 1 is a key component connecting the frame 2 and the rear wheel assembly (not shown in the figure). Its front end needs to swing up and down relative to the frame 2 about a horizontal axis to achieve the shock absorption function of the rear suspension. To achieve this pivotal connection, the front end of the rear swingarm 1 is designed as a forked structure, forming two parallel mounting seats 11 spaced a certain distance apart. Each mounting seat 11 is usually a cylindrical structure, with rubber bushings or needle roller bearings press-fitted inside to reduce rotational friction and absorb some vibration.

[0025] The rear flat fork connection structure of this utility model mainly includes three core parts: the lug assembly, the bridge-type connecting plate assembly 5, and the through-type spindle 6.

[0026] In this invention, the lug assembly includes a pair of structurally symmetrical left lugs 3 and right lugs 4, which are respectively and firmly fixed to the left and right sides of the lower rear part of the frame 2. The fixing method can be high-strength welding, such as CO2 gas shielded welding or argon arc welding, to ensure a permanent and reliable connection between them and the frame 2.

[0027] In other alternative implementations, high-strength bolts can be used for fastening. Each lug is made of sufficiently thick steel plate by stamping or laser cutting, and has precision-machined pivot mounting holes. The central axes of these two mounting holes are strictly collinear, providing a reference for the installation accuracy of the entire connection structure.

[0028] The left support ear 3 has a left mounting position 31 in the middle, and the right support ear 4 has a right mounting position 41 in the middle. Both the left mounting position 31 and the right mounting position 41 protrude toward the bridge connecting plate assembly 5. The left mounting position 31 and the right mounting position 41 form a left clearance space 32 and a right clearance space 42 on the side opposite to the bridge connecting plate assembly 5. The left clearance space 32 and the right clearance space 42 facilitate the installation of the through-type mandrel 6.

[0029] See also Figures 1-4 and Figure 6 As shown, the bridge-type connecting plate assembly 5 is a separate, pre-assembled rigid component. Its entirety is designed as a robust frame structure for installation within the space between the two mounting seats 11 of the rear swingarm 1.

[0030] Specifically, the bridge-type connecting plate assembly 5 includes a left bridge-type connecting plate 51, a right bridge-type connecting plate 52, and at least one horizontal tube for connecting the two connecting plates. In this preferred embodiment, two horizontal tubes are provided, namely a first horizontal tube 53 and a second horizontal tube 54. The ends of the first horizontal tube 53 and the second horizontal tube 54 are respectively connected to the left bridge-type connecting plate 51 and the right bridge-type connecting plate 52 through perforations, together forming a stable frame similar to an "H" shape or a "U" shape.

[0031] It should be noted that the horizontal tubes here are not limited to two, but can also be multiple, to achieve the connection and fixation of the left bridge connecting plate 51 and the right bridge connecting plate 52.

[0032] The shapes and dimensions of the left and right bridge connecting plates 51 and 52 are carefully designed so that their outer contours match the inner contours of the two mounting seats 11 of the rear horizontal fork 1, ensuring a tight fit after installation. The first cross tube 53 is a hollow tubular structure whose inner diameter matches the diameter of the through-type mandrel, and its axis is positioned directly opposite the pivot center of the rear horizontal fork 1. The second cross tube 54 mainly serves to strengthen the connection and improve the torsional and bending resistance of the entire bridge connecting plate assembly 5. These components are typically made of high-quality carbon structural steel or alloy steel to ensure sufficient strength and rigidity.

[0033] In a preferred embodiment, both the left axle connecting plate 51 and the right axle connecting plate 52 are preferably angular plate structures, each including a first plate 511 and a second plate 512. The first plate 511 and the second plate 512 are integrally formed. The first plate 511 is perpendicular to the connecting tube of the frame 2, and the second plate 512 is parallel to the connecting tube of the frame 2. The first plate 511 and the second plate 512 are provided with clearance spaces 56 adapted to the connecting tube of the frame 2, which facilitates the clearance of the connecting tube of the frame 2. In this embodiment, the first plate 511 is welded to the connecting tube of the frame 2.

[0034] As a preferred implementation method, such as Figure 4 As shown, one or more center support mounting holes 55 can be opened in the lower part of the bridge connecting plate assembly 5, for example on the second horizontal tube 54 or in the extension of the connecting plate. These mounting holes are used to install the central support frame (i.e., center support) of the electric vehicle, so that the mounting points that originally needed to be set separately on the frame 2 can be integrated into the reinforcing component. This not only simplifies the design of the frame 2 and reduces welding points, but also improves the functional integration of the components and reduces production costs.

[0035] The through-type mandrel 6 in this invention is a single, long shaft, typically made of high-strength alloy steel that has undergone tempering or surface hardening to withstand enormous shear forces and bending moments. One end has a large head to provide axial positioning and a preload application surface during installation, while the other end is threaded for engagement with a lock nut. The total length of the through-type mandrel 6 is precisely calculated to ensure it can completely pass through the side lug assemblies, the side mounting seats 11, and the central bridge-type connecting plate assembly 5, with sufficient thread length for locking.

[0036] The assembly process of the rear flat fork connection structure in this utility model is described in detail below.

[0037] First, place the prefabricated bridge-type connecting plate assembly 5 between the two mounting seats 11 at the front end of the rear swingarm 1. Then, align the rear swingarm 1 assembly with the bridge-type connecting plate assembly 5 with the lug assembly on the frame 2, so that the through hole of the mounting seat 11 is aligned with the pivot mounting hole on the lug assembly.

[0038] Next, insert the through-type mandrel 6 starting from one side of the frame 2 (e.g., the left side), passing sequentially through the left-side lug assembly, the left-side mounting base 11 (and its internal bushing or bearing), the first horizontal tube 53 of the bridge connecting plate assembly 5, the right-side mounting base 11 (and its internal bushing or bearing), and finally exiting through the right-side lug assembly. Install washers and self-locking nuts on the threaded end of the through-type mandrel 6, and tighten it using a torque wrench to apply the preset torque.

[0039] Please see Figure 1 The diagram clearly shows the assembled structure. As can be seen, the bridge-type connecting plate assembly 5 is securely "clamped" between the two mounting seats 11 of the rear swingarm 1, which in turn is "clamped" between the two lug assemblies of the frame 2. The through-type spindle 6 acts like a sturdy "pin," coaxially and tightly binding these three key components (the lug assemblies of the frame 2, the rear swingarm 1, and the bridge-type connecting plate assembly 5) together, forming a composite, pivotable integrated structure.

[0040] Now combine Figure 1-7 To analyze the working principle and beneficial effects of this structure.

[0041] When an electric vehicle is in motion, especially during extreme maneuvers such as rapid acceleration, sudden braking, or high-speed cornering, the rear wheel experiences tremendous driving, braking, or lateral forces from the ground. These loads are first transmitted to the rear swingarm 1. In a traditional single-point articulated structure, these forces cause slight relative torsional or lateral displacement at the two pivot points of the rear swingarm 1, leading to instability at the rear of the vehicle and problems such as swaying or poor traction.

[0042] However, in the structure of this embodiment, due to the presence of the bridge-type connecting plate assembly 5, it acts like a bridge, rigidly connecting the left and right mounting seats 11 of the rear horizontal fork 1. When one mounting seat 11 is subjected to a force, this force is quickly transmitted to the other mounting seat 11 through the bridge-type connecting plate assembly 5, thereby effectively suppressing any relative displacement and torsion between the two.

[0043] The entire load transfer path is as follows: the load from the rear wheel is transferred to the rear swingarm 1, and then to the mounting base 11. At this point, the load is decomposed. One part is directly transferred to the lug assembly through the through-type spindle 6, and the other part forms an internal force balance between the two pivot points through the bridge-type connecting plate assembly 5.

[0044] Ultimately, all forces are evenly and smoothly transmitted to the frame 2 through the robust composite structure of the through-type spindle 6 and the lug assembly. This structure forms a short and robust load transfer closed loop, greatly improving the torsional stiffness and structural strength of the entire pivot connection area. The driver can clearly feel a more direct handling response and a more stable vehicle posture under extreme conditions, thus significantly improving driving safety.

[0045] Furthermore, this structure effectively optimizes stress distribution. In traditional structures, all loads are concentrated in two narrow areas connecting the pivot and the frame 2, easily leading to stress concentration and fatigue damage. In this invention, the load is distributed over a wider area, shared by the through-type spindle 6, the bridge-type connecting plate assembly 5, the mounting base 11, and the lug assembly, significantly reducing peak stress and thus greatly enhancing the fatigue resistance of the connection point, extending the service life of the entire connection structure and even the frame 2.

[0046] The rear swingarm 1 of this utility model can be an integrally welded rear swingarm 1 assembly, with a mounting position 12 for mounting a hub motor at its rear end. This design is very common in modern electric vehicles. Due to the large mass of the hub motor, the rigidity requirements of the connection point of the rear swingarm 1 are higher. The connection structure provided in this application can perfectly adapt to this application scenario and provide stable and reliable support.

[0047] like Figure 8 As shown, through FEA analysis, the maximum deformation of the rear horizontal fork 1 when resisting the same Y+ direction 2200N lateral force decreased from 1.432 to 1.072, and the stiffness increased by 33.6%. At the same time, the maximum stress at the pivot point decreased from 237.5MPa to 135.7MPa, and the maximum stress was reduced to 57% of the original, and the strength increased by about 75%.

[0048] In summary, this utility model provides an electric vehicle, which includes a frame 2, a rear swingarm 1, a central support frame (not shown in the figure), and the aforementioned rear swingarm connection structure. Through ingenious design, this structure significantly improves the vehicle's dynamic performance and structural reliability.

[0049] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

[0050] In the description of this utility model, it should be noted that, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and 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, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0051] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0052] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the protection scope of the claims.

Claims

1. A rear swingarm connection structure for connecting a rear swingarm and a frame, characterized in that, It includes a through-type spindle, a lug assembly, and a bridge-type connecting plate assembly. The lug assembly is fixedly mounted on both sides of the rear end of the frame, and the bridge-type connecting plate assembly is located between the mounting seats of the rear swingarm. The through-type spindle passes through the lug assembly, the mounting seats, and the bridge-type connecting plate assembly.

2. The rear flat fork connection structure according to claim 1, characterized in that, The support lug assembly includes a left support lug and a right support lug, both ends of which are connected to the vehicle frame.

3. The rear flat fork connection structure according to claim 2, characterized in that, The bridge-type connecting plate assembly includes a left bridge-type connecting plate and a right bridge-type connecting plate connected to the vehicle frame. At least one set of horizontal tubes is provided between the left bridge-type connecting plate and the right bridge-type connecting plate, and the horizontal tubes pass through both the left bridge-type connecting plate and the right bridge-type connecting plate.

4. The rear flat fork connection structure according to claim 3, characterized in that, The horizontal tube includes a first horizontal tube and a second horizontal tube. The two ends of the first horizontal tube and the second horizontal tube are simultaneously installed on the left bridge connecting plate and the right bridge connecting plate. The through-type mandrel passes through the first horizontal tube.

5. The rear flat fork connection structure according to claim 3, characterized in that, Both the left bridge connecting plate and the right bridge connecting plate are designed as angular plate structures, each including a first plate and a second plate. The first plate and the second plate are integrally formed. The first plate is perpendicular to the connecting tube of the frame, and the second plate is parallel to the connecting tube of the frame. The second plate is fixedly mounted on the connecting tube of the frame.

6. The rear flat fork connection structure according to claim 5, characterized in that, The first plate and / or the second plate are provided with clearance space adapted to the connecting tube of the vehicle frame.

7. The rear flat fork connection structure according to claim 3, characterized in that, The lower ends of both the left and right bridge-type connecting plates are provided with mounting holes for installing the central support base.

8. The rear flat fork connection structure according to any one of claims 1-7, characterized in that, The rear swingarm is an integral welded rear swingarm assembly, with the mounting base at its front end and the hub motor mounting position at its rear end.

9. An electric vehicle, characterized in that, The rear swingarm connection structure, as described in any one of claims 1-8, further includes a rear swingarm and a frame, wherein the rear swingarm connection structure is used to connect the rear swingarm, the frame, and the central support frame.

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