A bottom tube and middle tube connection structure for an electric vehicle frame and an electric vehicle frame.

Abstract

This utility model discloses a connection structure between the bottom tube and the middle tube of an electric vehicle frame, as well as the electric vehicle frame itself. The connection structure includes a middle tube and a bottom tube. The middle tube is a round tube with a first groove on its bottom side. The first groove includes a first upper end face and a first side end face. The bottom tube is a square tube. The height and width of the first groove match the height and width of the bottom tube, respectively. The rear end of the bottom tube has an arc-shaped structure that matches the wall shape of the middle tube. The upper end face of the bottom tube abuts against the first upper end face and is connected by a first weld. The side end face of the bottom tube abuts against the first side end face and is connected by a second weld. The rear end face of the bottom tube abuts against the middle tube and is connected by a third weld. The connection structure between the middle tube and the bottom tube of the frame is optimized, eliminating the original reinforcing plate design. The bottom tube and the middle tube adopt an insert connection, reducing the number of parts, lightening the overall vehicle weight, shortening the weld, optimizing material preparation and welding processes, and maintaining the overall strength of the vehicle.

Description

Technical Field

[0001] This utility model relates to the technical field, and in particular to a connection structure between the bottom tube and the middle tube of an electric vehicle frame and an electric vehicle frame. Background Technology

[0002] Electric bicycles are widely used by consumers as a daily means of transportation. The frame is one of the main components of an electric bicycle, serving as the core structural framework of the entire vehicle and supporting the body and connecting various parts. The main body of the electric bicycle frame is usually made of metal tubing or composite materials, formed through welding or die casting processes. The frame is the supporting structure for the entire electric bicycle, and its structural strength is paramount. In existing technologies, the electric bicycle frame structure typically involves adding reinforcing plates welded together at the connection between the bottom tube and the middle tube. The connection between the middle tube and the bottom tube requires welding on three sides, with a reinforcing plate fully welded to the outside for reinforcement. However, this approach has the following drawbacks: 1) The connection structure is complex, requiring three interconnected parts, and the reinforcing plates vary widely in terms of vehicle model compatibility, leading to high costs. 2) Tooling and fixture positioning is difficult, hindering the angle and position of the welding torch, resulting in higher welding difficulty, longer weld lengths, and a higher risk of welding defects, leading to low production efficiency. 3) During the production and processing of the reinforcing plates, various factors inevitably interfere, easily creating large gaps at the connection between the reinforcing plates and the middle and bottom tubes, increasing welding difficulty and resulting in a high product defect rate. Utility Model Content

[0003] The purpose of this utility model is to address the deficiencies of the existing technology by providing a connection structure between the bottom tube and the middle tube of an electric vehicle frame, as well as an electric vehicle frame.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] In a first aspect, a bottom tube and middle tube connection structure for an electric vehicle frame is provided, comprising a middle tube and a bottom tube, characterized in that: the middle tube is a round tube, a first groove is provided on the bottom side of the middle tube, the first groove includes a first upper end face and a first side end face, the bottom tube is a square tube, the height and width of the first groove are matched with the height and width of the bottom tube respectively, the rear end of the bottom tube is an arc-shaped structure and matches the wall shape of the middle tube, the upper end face of the bottom tube abuts against the first upper end face and is connected by a first weld, the side end face of the bottom tube abuts against the first side end face and is connected by a second weld, and the rear end face of the bottom tube abuts against the middle tube and is connected by a third weld.

[0006] Furthermore, the first upper end face and the first side end face are perpendicular to each other.

[0007] Furthermore, the dimensions of the first slot are 52×12mm.

[0008] Furthermore, the sum of the lengths of the first weld bead, the second weld bead, and the third weld bead is 160mm.

[0009] Furthermore, a second groove is provided on the bottom side of the middle tube. The second groove is opposite to the first groove. The second groove includes a second upper end face and a second side end face. The bottom tube extends out from the second groove. The third weld connects the rear end of the bottom tube and the second upper end face. The side end face of the bottom tube abuts against the second side end face and is connected by a fourth weld.

[0010] Furthermore, the thickness of the bottom tube gradually decreases along the direction from the first slot to the second slot.

[0011] Furthermore, the dimensions of the second slot are 52×8mm.

[0012] Furthermore, the second upper end face and the second side end face are perpendicular to each other.

[0013] Furthermore, the sum of the lengths of the first weld bead, the second weld bead, the third weld bead, and the fourth weld bead is 170 mm.

[0014] In a second aspect, an electric vehicle frame is provided, characterized in that it includes the bottom tube and middle tube connection structure of the electric vehicle frame described in the first aspect.

[0015] Compared with the prior art, the beneficial effects of this utility model are:

[0016] 1. The connection structure between the frame center tube and the bottom tube has been optimized, eliminating the original reinforcing plate design. The bottom tube and center tube adopt an insert connection, reducing the number of parts, lightening the overall vehicle weight, shortening the weld bead, optimizing material preparation and welding processes, and maintaining the overall strength of the vehicle.

[0017] 2. The middle and bottom tubes are processed by laser cutting, which results in high precision and improved quality of the tube material. The processing technology is simple and does not require mold opening, thus improving production efficiency.

[0018] 3. The number of tooling fixture parts for positioning is reduced, thereby reducing the difficulty of positioning and welding.

[0019] Other features and advantages of this invention will be set forth in the following description or may be learned by practicing this invention. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the overall structure of Example 1;

[0021] Figure 2 This is a schematic diagram of the tube structure in Example 1;

[0022] Figure 3 This is a schematic diagram of the bottom tube structure in Example 1;

[0023] Figure 4 This is a schematic diagram of the overall structure of Example 2;

[0024] Figure 5 This is a schematic diagram of the tube structure in Example 2;

[0025] Figure 6 This is a schematic diagram of the bottom tube structure in Example 2;

[0026] In the diagram: 1-middle tube, 2-bottom tube, 3-first groove, 4-first weld bead, 5-second weld bead, 6-third weld bead, 7-second groove, 8-fourth weld bead, 21-top end face of bottom tube, 22-side end face of bottom tube, 31-first top end face, 32-first side end face, 71-second top end face, 72-second side end face. Detailed Implementation

[0027] To enhance understanding of this utility model, we will now describe it in further detail with reference to the accompanying drawings. This embodiment is only used to explain this utility model and does not constitute a limitation on the scope of protection of this utility model.

[0028] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., 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.

[0029] Furthermore, the terms "first," "second," and "third" 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. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0030] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," "fixing," and "setting," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; 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; and they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0031] Example 1

[0032] like Figure 1-3 As shown, an electric vehicle frame has a bottom tube and middle tube connection structure, including a middle tube 1 and a bottom tube 2.

[0033] The middle tube 1 is a round tube. The bottom side of the middle tube 1 is laser-cut with a first groove 3. The first groove 3 includes a first upper end face 31 and first side end faces 32 on both sides of the first upper end face 31.

[0034] The bottom tube 2 is a square tube. The height and width of the first groove 3 are matched with the height and width of the bottom tube 2, respectively. The rear end of the bottom tube 2 is laser-cut into an arc-shaped structure, which matches the shape of the inner wall of the middle tube 1. The upper end face 21 of the bottom tube abuts against the first upper end face 31 and is connected by the first weld 4. The side end face 22 of the bottom tube abuts against the first side end face 32 and is connected by the second weld 5. The rear end of the bottom tube 2 abuts against the inner side of the middle tube 1 and is connected by the third weld 6.

[0035] Preferably, the first upper end face 31 and the first side end face 32 of the first slot 3 are perpendicular to each other.

[0036] Preferably, the size of the first slot 3 is 52×12mm.

[0037] Preferably, the sum of the lengths of the first weld pass 4, the second weld pass 5, and the third weld pass 6 is 160mm.

[0038] In this embodiment, the total weld length of the bottom and middle pipe connection structure is 120mm shorter than that of the existing weld structure. After 200,000 vibration durability tests, no cracks, tears, or other defects occurred in the connection structure.

[0039] Example 2

[0040] like Figure 4-6 As shown, an electric vehicle frame has a bottom tube and middle tube connection structure, including a middle tube 1 and a bottom tube 2.

[0041] The middle tube 1 is a round tube. The bottom side of the middle tube 1 is laser-cut with a first groove 3 and a second groove 7. The first groove 3 includes a first upper end face 31 and first side end faces 32 on both sides of the first upper end face 31. The second groove 7 is opposite to the first groove 3 and includes a second upper end face 71 and second side end faces 72 on both sides of the second upper end face 71.

[0042] The bottom tube 2 is a square tube. The height and width of the first slot 3 and the second slot 7 are matched with the height and width of the bottom tube 2, respectively. The bottom tube 2 passes through the first slot 3 and extends out from the second slot 7. The upper end face 21 of the bottom tube abuts against the first upper end face 31 and the second upper end face 71, and is connected by the first weld bead 4 and the third weld bead 6, respectively. The side end face 22 of the bottom tube abuts against the first side end face 32 and the second side end face 72, and is connected by the second weld bead 5 and the fourth weld bead 8, respectively. The thickness of the bottom tube 2 gradually decreases along the direction from the first slot 3 to the second slot 7.

[0043] Preferably, the first upper end face 31 and the first side end face 32 of the first slot 3 are perpendicular to each other, and the second upper end face 71 and the second side end face 72 of the second slot 7 are perpendicular to each other.

[0044] Preferably, the dimensions of the first slot 3 are 52×12mm, and the dimensions of the second slot 7 are 52×8mm.

[0045] Preferably, the sum of the lengths of the first weld pass 4, the second weld pass 5, the third weld pass 6, and the fourth weld pass 8 is 170mm.

[0046] In this embodiment, the total weld length of the bottom and middle pipe connection structure is shortened by 110mm compared to the existing weld structure. After 200,000 vibration durability tests, no cracks, tears, or other defects occurred in the connection structure.

[0047] The connection structure in Embodiment 1 and Embodiment 2 has been optimized, eliminating the reinforcing plate design in the prior art. The bottom tube 2 and the middle tube 1 are connected by an insertion type, reducing the number of parts, reducing the overall vehicle weight, shortening the weld bead, and optimizing the material preparation and welding process. After fatigue testing, the overall strength of the vehicle has not been reduced.

[0048] Example 3

[0049] An electric vehicle frame adopts the bottom tube and middle tube connection structure of the electric vehicle frame described in Embodiment 1 or Embodiment 2.

[0050] The above specific embodiments are only for illustrating the technical concept and structural features of this utility model, and are intended to enable those skilled in the art to implement them. However, the above content does not limit the protection scope of this utility model. Any equivalent changes or modifications made in accordance with the spirit and essence of this utility model shall fall within the protection scope of this utility model.

Claims

1. A bottom tube and middle tube connection structure for an electric vehicle frame, comprising a middle tube (1) and a bottom tube (2), characterized in that: The middle tube (1) is a round tube. A first groove (3) is provided on the bottom side of the middle tube (1). The first groove (3) includes a first upper end face (31) and a first side end face (32). The bottom tube (2) is a square tube. The height and width of the first groove (3) are matched with the height and width of the bottom tube (2). The rear end of the bottom tube (2) is an arc-shaped structure that matches the shape of the wall of the middle tube (1). The upper end face (21) of the bottom tube abuts against the first upper end face (31) and is connected by a first weld (4). The side end face (22) of the bottom tube abuts against the first side end face (32) and is connected by a second weld (5). The rear end of the bottom tube (2) abuts against the middle tube (1) and is connected by a third weld (6).

2. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 1, characterized in that: The first upper end face (31) and the first side end face (32) are perpendicular to each other.

3. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 1, characterized in that: The dimensions of the first slot (3) are 52×12mm.

4. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 1, characterized in that: The sum of the lengths of the first weld (4), the second weld (5), and the third weld (6) is 160 mm.

5. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 1, characterized in that: The bottom side of the middle tube (1) is also provided with a second slot (7), which is opposite to the first slot (3). The second slot (7) includes a second upper end face (71) and a second side end face (72). The bottom tube (2) extends out from the second slot (7). The third weld (6) connects the rear end of the bottom tube (2) and the second upper end face (71). The side end face (22) of the bottom tube abuts against the second side end face (72) and is connected by a fourth weld (8).

6. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 5, characterized in that: The thickness of the bottom tube (2) gradually decreases along the direction from the first slot (3) to the second slot (7).

7. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 5, characterized in that: The second slot (7) has a size of 52×8mm.

8. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 5, characterized in that: The second upper end face (71) and the second side end face (72) are perpendicular to each other.

9. The connection structure between the bottom tube and the middle tube of an electric vehicle frame according to claim 5, characterized in that: The sum of the lengths of the first weld (4), the second weld (5), the third weld (6) and the fourth weld (8) is 170 mm.

10. An electric vehicle frame, characterized in that: The electric vehicle frame includes the bottom tube and middle tube connection structure as described in any one of claims 1-9.

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