Electric vehicle lower frame and chassis

Abstract

The present invention discloses a lower frame of an electric vehicle and a chassis using the frame, and relates to the technical field of new energy vehicles. The lower frame includes a front frame, a battery box fixing frame, a rear frame and a battery box lower shell. The front frame, the battery box fixing frame, the rear frame and the battery box lower shell are all thin-walled aluminum alloy parts. The front frame is located in front of the battery box fixing frame, and the front frame and the front side of the battery box frame are screwed together by four bolt groups. The rear frame is located behind the battery box fixing frame, and the rear frame and the rear side of the battery box frame are screwed together by four bolt groups. The battery box lower shell is located inside the battery box fixing frame, and the battery box lower shell is connected to the battery box frame by a screw around the bottom. The lower frame has the characteristics of no need for welding, simple process, high precision, light weight, high structural strength, modular assembly, and can adapt to small batch or customized production of electric vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a lower frame and chassis of an electric vehicle. Background Art

[0002] Under the dual pressure of environment and energy, the development of new energy vehicles in my country is becoming more and more urgent. Electrification and intelligence are important development directions of the new energy vehicle industry. At present, there are two main ways to develop electric vehicles. One is to transform the traditional fuel vehicle model, modify the bottom of the frame and install a battery pack. The other is to design the frame in accordance with the needs of electric vehicles and battery characteristics. This type of frame usually adopts one or several welded combination structures of aluminum sheet metal, aluminum profiles, and small cast aluminum parts.

[0003] Directly converting existing fuel vehicles into battery vehicles faces little difficulty in manufacturing and production. However, since traditional sedans usually use a load-bearing body made of steel sheet metal, the electric vehicles developed often have the following disadvantages: insufficient endurance due to heavy weight, unreasonable layout of the three-electric configuration due to the limitations of the existing frame, difficulty in realizing intelligent and networked layout requirements, and small ground clearance after adding a battery pack to the bottom.

[0004] The newly developed electric vehicle frame directly meets the needs of electric vehicles. It has a lower frame structure that is independent of the body to install the battery pack. In order to improve the battery life, aluminum is usually used to achieve lightweight. At present, there are mainly two forms: welding aluminum profiles and combining aluminum profiles, sheet metal parts and small castings. However, both of the above two types of frames have the following disadvantages:

[0005] 1) Due to the existence of a large number of welding points and welds, the structural safety and reliability are greatly reduced: the single parts made of sheet metal and aluminum profiles are simple in shape, and a large number of parts combinations and welding connections are required to form a frame that can meet the load-bearing and functional requirements. For parts of the frame with large loads and multi-functional requirements (such as the connection between the shock tower and the longitudinal beam, the connection between the transverse beam and the longitudinal beam, and other key positions), there are many connecting parts and links, and the welding path is complicated. Compared with steel welding, aluminum welding is difficult, and the welding process is not yet mature. Welding deformation and weld strength are problems that need to be solved.

[0006] 2) The frame structure is heavy: Due to the unique process requirements of sheet metal parts and profile parts, the material layout is redundant in some parts or even in a large area, and a large number of connection links are stacked, which hinders the lightweight design of the frame.

[0007] 3) The production process is complex and the initial investment is large: The frame is made of various parts made by various process methods such as various special-shaped extruded profiles, sheet metal parts, castings, etc., with many welding and riveting links and complex production processes. In order to ensure that the frame obtains sufficient manufacturing accuracy, the production of the frame is inseparable from a large number of welding tools and special welding equipment. The production line requires a one-time large-scale investment. Electric vehicles have not yet been widely accepted by consumers, sales are limited, and they are facing the need for modification and performance improvement. It is difficult for car companies to achieve profitability under small batch conditions. Summary of the invention

[0008] To this end, the present invention provides a lower frame and chassis of an electric vehicle to avoid welding, improve the structural strength of key stress-bearing positions of the frame, and lighten the vehicle body.

[0009] In order to achieve the above purpose, the embodiment of the present invention provides the following technical solutions:

[0010] According to a first aspect of the present invention, a lower frame of an electric vehicle comprises a front end frame, a battery box fixing frame, a rear end frame and a battery box lower shell, wherein the front end frame, the battery box fixing frame, the rear end frame and the battery box lower shell are all thin-walled aluminum alloy parts, the front end frame is located in front of the battery box fixing frame, the front end frame is screwed to the front end and the front side of the battery box frame by four bolt groups, the rear end frame is located behind the battery box fixing frame, the rear end frame is screwed to the rear end and the rear side of the battery box frame by four bolt groups, the battery box lower shell is located inside the battery box fixing frame, and the battery box lower shell is connected to the battery box frame by a circle of screws at the bottom.

[0011] Furthermore, the front end frame includes a front longitudinal beam, a front shock tower, a front mounting frame of a battery box fixing frame, a front cross beam, a support frame and a water tank cross beam that are symmetrical about the longitudinal plane of the frame. The front longitudinal beam and the front shock tower are integrally formed, the rear end of the front longitudinal beam is fixedly connected to the L-shaped corner of the front mounting frame of the battery box fixing frame, the two ends of the front cross beam are respectively fixedly connected to the left and right front longitudinal beams, and the support frame and the water tank cross beam are fixedly connected to the front end frame.

[0012] Furthermore, the front longitudinal beam is a hollow structural beam with a curved busbar and a variable cross-section rectangle, the cross-section increases from small to large from front to rear, and openings are provided at the front and rear ends and sides of the left and right front longitudinal beams; the front shock absorber tower is a thin-walled reinforced shell and a structure with triangular longitudinal ribs inside, and is connected to the front longitudinal beam through a rounded transition; the battery box fixed frame mounting bracket has two L-shaped corners, and each corner has two groups of bolt holes on both sides; the front cross beam is provided with a mounting bracket and a mounting hole, and has a hollow design.

[0013] Furthermore, the battery box fixing frame is a rectangular frame structure, the longitudinal beams and transverse beams of the battery box fixing frame are connected at the corners and formed in one piece, and the upper part of the corner has a large rounded corner.

[0014] Furthermore, the longitudinal beams and the transverse beams of the battery box fixing frame are both hollow beams with rectangular cross-sections, with a plurality of reinforcing ribs inside the beams and a plurality of openings in the middle of the outer side of the beams.

[0015] Furthermore, the rear end frame includes a rear longitudinal beam, a rear shock tower, a rear cross beam and a rear mounting frame of a battery box fixing frame that are symmetrical about the longitudinal plane of the frame. The rear longitudinal beam and the rear shock tower are connected by a rounded transition. The rear longitudinal beam is a hollow beam with a rectangular cross-section. The front end of the rear longitudinal beam has a spatial curved busbar and is connected to the corner of the rear mounting frame of the battery box fixing frame. The two ends of the rear cross beam are respectively fixed to the left and right rear longitudinal beams.

[0016] Furthermore, the inner side of the rear shock absorber tower is provided with two triangular ribs which are transitionally connected with the rounded corners of the rear longitudinal beams. The two ends of the rear cross beam are overlapped on the two rear longitudinal beams through large rounded corners respectively. The rear mounting frame of the battery box fixing frame has two L-shaped corners, and each corner has a group of bolt connection holes on both sides.

[0017] Furthermore, the lower shell of the battery box includes a shell body and a mounting structure, wherein the mounting structure surrounds the shell body and is connected to the lower surface of the shell body, and a plurality of through holes are evenly distributed on the mounting structure for connecting to a fixed frame of the battery box.

[0018] Furthermore, the battery box lower shell body is located inside the battery box fixing frame.

[0019] According to a second aspect of the present invention, an electric vehicle chassis is provided, which is the lower frame of the electric vehicle according to the first aspect of the present invention.

[0020] The present invention has the following advantages:

[0021] 1. The front frame, battery box fixing frame, rear frame and battery box lower shell are all thin-walled aluminum alloy parts, which realizes the lightweight and integrated structure, greatly reduces the number of frame parts, greatly simplifies the assembly process, and the four major components are connected by bolts to achieve modular assembly, so that the entire lower frame avoids a large number of welding links, and can even be assembled without any welding, avoiding welding deformation and improving structural safety and reliability;

[0022] 2. Compared with the frame modified from traditional fuel vehicles and welded frames, it can achieve lightweight;

[0023] 3. The structural layout of the frame is adapted to the characteristics of electric vehicles. The battery box is arranged inside the middle frame, which effectively protects the safety of the battery box in the event of a car collision, saves space, and increases the ground clearance at the bottom of the frame;

[0024] 4. It can improve the structural strength and rigidity of the frame at key stress-bearing parts; in the parts of the frame with large load-bearing and multi-functional requirements (such as the connection between the shock tower and the longitudinal beam, the connection between the transverse beam and the longitudinal beam, and other key positions), the ribs with large rounded transitions are used to strengthen the one-piece connection, which effectively increases the structural rigidity, strength and reliability;

[0025] 5. Through reasonable structural design, it can be manufactured by the existing flexible investment casting production line, without the need for special casting equipment, avoiding the investment in welding tooling and welding production lines, and can adapt to small-batch production and customization needs; it is conducive to achieving profitability under the current situation of small-batch production of electric vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the implementation methods of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for the implementation methods or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0027] The structures, proportions, sizes, etc. illustrated in this specification are only used to match the contents disclosed in the specification so as to facilitate understanding and reading by persons familiar with the technology. They are not used to limit the conditions under which the present invention can be implemented, and therefore have no substantial technical significance. Any structural modification, change in proportion or adjustment of size shall still fall within the scope of the technical contents disclosed in the present invention without affecting the effects and purposes that can be achieved by the present invention.

[0028] Figure 1 It is a structural schematic diagram of the lower frame of an electric vehicle;

[0029] Figure 2 It is a structural schematic diagram of the front end frame (top view);

[0030] Figure 3 It is a structural schematic diagram of the front-end frame (side view);

[0031] Figure 4 It is a schematic diagram of the structure of the front shock tower;

[0032] Figure 5 It is a structural schematic diagram of the battery box fixing frame mounting frame;

[0033] Figure 6It is a structural schematic diagram (axonometric diagram) of the battery box fixing frame;

[0034] Figure 7 It is a structural schematic diagram of the battery box fixing frame (bottom view);

[0035] Figure 8 It is a structural schematic diagram of the battery box fixing frame (side view);

[0036] Fig. 9 For along Figure 7 The cross-section diagram of the AA line;

[0037] Fig.10 For along Figure 8 Cross-sectional view of the mid-CC line;

[0038] Fig.11 is a schematic diagram of the structure of the rear end frame;

[0039] Fig.12 It is a schematic diagram of the structure of the lower shell of the battery box.

[0040] In the figure:

[0041] 1-front end frame, 11-front longitudinal beam, 12-front shock tower, 13-support frame, 14-water tank cross beam, 15-battery box fixed frame mounting frame, 16-front cross beam, 111-first reinforcing rib, 121-thin-wall shell, 122-transverse rib, 123-longitudinal rib, 151-bolt hole, 152-second reinforcing rib;

[0042] 2-battery box fixing frame, 21-third reinforcing rib, 22-opening, 23-first large fillet, 24-bolt connection hole, 25-threaded connection hole;

[0043] 3-rear end frame, 31-rear longitudinal beam, 32-rear shock tower, 33-rear cross beam, 34-battery box fixing frame rear mounting frame, 35-second largest fillet, 321-triangular rib plate;

[0044] 4-battery box lower shell, 41-shell body, 42-installation structure. DETAILED DESCRIPTION

[0045] The following is a description of the implementation of the present invention by specific embodiments. People familiar with the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0046] The terms such as "upper", "lower", "left", "right", "middle", etc. cited in this specification are only for the convenience of description and are not intended to limit the scope of implementation of the present invention. Changes or adjustments to their relative relationships should be regarded as within the scope of implementation of the present invention without substantially changing the technical content.

[0047] Example 1

[0048] refer to Figures 1 to 12 Embodiment 1 provides a lower frame of an electric vehicle and a chassis using the frame.

[0049] refer to Figure 1 The lower frame consists of four parts: the front frame 1, the battery box fixing frame 2, the rear frame 3 and the battery box lower shell 4. The front frame 1, the battery box fixing frame 2, the rear frame 3 and the battery box lower shell 4 are all thin-walled aluminum alloy parts. The front frame 1 is screwed to the front end and front side of the battery box frame 2 by four bolt groups; the rear frame 3 is screwed to the rear end and rear side of the battery box frame 2 by four bolt groups; the battery box lower shell 4 is connected to the battery box frame 2 by a circle of screws at the bottom. This minimizes the number of parts, reduces the connection links, and greatly reduces the workload of machining and assembly. The four major components all have the characteristics of large thin-walled integrally formed complex structures, with a basic wall thickness of 3mm, which ensures that the frame has sufficient strength and rigidity, while achieving lightweight frame.

[0050] refer to Figure 2 , the front end frame 1 can be divided into the following parts: a front longitudinal beam 11, a front shock tower 12, a battery box fixed frame mounting frame 15, and a front cross beam 16 that are symmetrical about the longitudinal plane of the frame. Among them, the front end frame 1 can be fixedly connected to the support frame 13 and the water tank cross beam 14. In this way, multiple closed-loop frame structures of the front end frame 1 are formed, which increases the rigidity of the frame and is beneficial to the bending and torsion resistance of the frame. The front longitudinal beam 11 and the front shock tower 12 are integrally formed and continuous with the same material. The thin-walled reinforced shell and triangular longitudinal rib structure of the front shock tower 12 are connected to the front longitudinal beam 11 through a rounded transition. The front shock tower 12 is a key and important position where the frame is subjected to force. The one-piece molding and longitudinal ribs increase the structural strength, and can effectively transfer the force of the front shock tower 12 to the front longitudinal beam 11, thereby improving the safety of the frame.

[0051] refer to Figure 2 and 3, wherein the front longitudinal beam 11 is a hollow structure with a curved generatrix and a variable cross-section rectangle, and the cross-section changes from small to large from front to rear along the longitudinal direction of the vehicle body. Due to the limitation of the frame layout space, the cross-section at B changes greatly, and a first reinforcing rib 111 is arranged at this position. The hollow structure realizes structural lightweight, and the arrangement of the variable cross-section and the first reinforcing rib 111 is conducive to realizing the lightweight design of the structure matching the load under limited space conditions, while increasing the structural strength and stability. The front and rear ends and the side of the front longitudinal beam 11 are provided with openings, which can provide a sand removal and sand cleaning process passage for the investment casting process. The rear end of the front longitudinal beam 11 is fixedly connected to the L-shaped corner of the battery box fixed frame mounting frame 15, and the three sides of the rectangular cross-section of the front longitudinal beam 11 are respectively transitionally connected to the upper, lower and outer side surfaces of the L-shaped corner of the battery box fixed frame mounting frame 15, so that the force on the front longitudinal beam can be transmitted backward through the battery box fixed frame and the structure is stable.

[0052] refer to Figure 4 The front shock tower 12 has a semi-barrel-shaped thin-walled shell 121, and a plurality of transverse ribs 122 and longitudinal ribs 123 are arranged inside and outside the thin-walled shell 121, so that the front shock tower has a grid-like box-shaped structure, and the longitudinal and transverse ribs, and the ribs and the thin-walled shell 121 are all rounded transitions. The front shock tower is an important stress point of the frame. Such an arrangement increases the bearing capacity of the shock tower to withstand vertical and impact loads, is conducive to improving the strength and rigidity of the shock tower, and at the same time meets the movement space of the shock absorber below the shock tower.

[0053] refer to Figure 5 The battery box fixing frame mounting frame 15 has two L-shaped corners, and each corner has two groups of bolt holes 151 on both sides, which are used to connect with the front end and front side bolts of the battery box frame 2. The battery box fixing frame mounting frame 15 is a C-shaped structure, with the open side facing the battery box fixing frame 2. A second reinforcing rib 152 is arranged around the bolt hole 151, which increases the strength of the bolt connection point and the structural rigidity of the entire battery box fixing frame mounting frame 15. The two ends of the front cross beam 16 are respectively connected to the left and right front longitudinal beams 11. The front cross beam 16 has a plurality of mounting brackets and mounting holes for installing electrical equipment, cable fixing holes, etc., which improves the versatility of the front cross beam 16. The front cross beam 16 has a plurality of hollow designs to effectively reduce the weight of the structure.

[0054] refer to Figures 6 to 10, the battery box fixing frame 2 is a rectangular frame structure. Its front end is connected to the front frame 1, and the rear end is connected to the rear frame 3, and the battery box lower shell 4 is installed inside the frame. The battery box fixing frame 2 is not only a mounting frame for the battery box lower shell 4, but also plays the role of the middle beam of the entire lower frame. The multi-functional and concentrated design reduces the number of parts and achieves a significant weight reduction. Each side of the battery box fixing frame 2 is a hollow beam with a rectangular cross-section, and there is a third reinforcing rib 21 inside the beam, and there are several openings 22 in the middle of both sides of the beam. These designs ensure structural strength and rigidity, while achieving lightweight structure and providing the necessary process path for casting. The longitudinal beam and the cross beam of the battery box fixing frame 2 are integrally formed at the corner, and the upper part of the corner has a first large fillet 23, which improves the torsional rigidity of the frame and even the entire frame. The battery box fixing frame 2, the battery box fixing frame 2 has two sets of bolt connection holes 24 on both sides of the four corners, which are used to connect with the front frame 1 and the rear frame 3. The bottom of the battery box fixing frame 2 has threaded connection holes 25, which are evenly distributed around the bottom and are used to connect with the battery box lower shell 4. The battery pack can be disassembled separately, which is convenient for replacement and maintenance of the battery pack. The battery box is arranged inside the battery box fixing frame, which can protect the battery box when the car is hit.

[0055] refer to Fig.11 , the rear end frame 3 can be divided into the following parts: a rear longitudinal beam 31 symmetrical about the longitudinal plane of the frame, a rear shock tower 32, a rear cross beam 33, a battery box fixing frame rear mounting frame 34 and a second large fillet 35. The rear longitudinal beam 31 and the rear shock tower 32 are connected by a fillet transition. There are two triangular ribs 321 on the inner side of the rear shock tower 32 and connected to the rear longitudinal beam 31 by a fillet transition, which increases the strength of the rear shock tower 32 itself and the connection strength between the rear shock tower 32 and the rear longitudinal beam 31. The rear longitudinal beam 31 is a hollow beam with a rectangular cross section. The front end of the rear longitudinal beam 31 has a spatial curved generatrix and is connected to the L-shaped corner of the battery box fixing frame rear mounting frame 34. The rear shock tower 32 can be divided into a curved tower top, a tower body and a reinforcing rib 321. The tower top has a group of connection holes for connecting to the shock absorber of the suspension system. The two ends of the rear cross beam 33 are respectively overlapped on the two rear longitudinal beams 31 through the second large fillet 35, which can significantly improve the torsional rigidity of the rear end frame. The battery box fixing frame rear mounting frame 34 has two L-shaped corners, and each corner has a set of bolt connection holes on both sides for connection with the battery box fixing frame 2.

[0056] refer to Fig.12 The battery box lower shell 4 is divided into a shell body 41 and a mounting structure 42. The mounting structure 42 surrounds the shell body 41 and is connected to the lower surface of the shell body 41. The mounting structure 42 has a number of evenly distributed through holes for connecting with the battery box fixing frame 2. This design saves space under the frame and ensures maximum ground clearance.

[0057] Although the present invention has been described in detail above by general description and specific embodiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A lower frame of an electric vehicle, characterized in that: It includes a front-end frame, a battery box fixing frame, a rear-end frame and a battery box lower shell, wherein the front-end frame, the battery box fixing frame, the rear-end frame and the battery box lower shell are all thin-walled aluminum alloy parts, the front-end frame is located in front of the battery box fixing frame, the front-end frame and the front side of the battery box frame are screwed together by four bolt groups, the rear-end frame is located behind the battery box fixing frame, the rear-end frame and the rear side of the battery box frame are screwed together by four bolt groups, the battery box lower shell is located inside the battery box fixing frame, and the battery box lower shell is connected to the battery box frame by a screw around the bottom; The front end frame comprises a front longitudinal beam, a front shock tower, a front mounting frame of a battery box fixing frame, a front cross beam, a support frame and a water tank cross beam symmetrical about the longitudinal plane of the frame, the front longitudinal beam and the front shock tower are integrally formed, the rear end of the front longitudinal beam is fixedly connected to the L-shaped corner of the front mounting frame of the battery box fixing frame, the two ends of the front cross beam are respectively fixedly connected to the left and right front longitudinal beams, and the support frame and the water tank cross beam are fixedly connected to the front end frame; The front longitudinal beam is a hollow structural beam with a curved generatrix and a variable cross-section rectangle, and the cross-section increases from small to large from front to rear. The front and rear ends and sides of the left and right front longitudinal beams are provided with openings; the front shock tower is a thin-walled reinforced shell and a structure with triangular longitudinal ribs inside, and is connected to the front longitudinal beam through a rounded transition; the battery box fixing frame mounting frame has two L-shaped corners, and each corner has two groups of bolt holes on both sides; the front cross beam is provided with a mounting bracket and a mounting hole, and has a hollow design; The front shock absorber tower has a semi-barrel-shaped thin-walled shell, and a plurality of transverse ribs and longitudinal ribs are arranged on the inner and outer sides of the thin-walled shell, so that the front shock absorber tower has a grid-like box-shaped structure, and the longitudinal and transverse ribs and the ribs and the thin-walled shell are all rounded transitions; The rear end frame includes a rear longitudinal beam, a rear shock tower, a rear cross beam and a battery box fixing frame rear mounting frame symmetrical about the longitudinal plane of the frame, the rear longitudinal beam and the rear shock tower are connected by a rounded transition, the rear longitudinal beam is a hollow beam with a rectangular cross section, the front end of the rear longitudinal beam has a spatial curve generatrix, and is connected to the corner of the battery box fixing frame rear mounting frame, and the two ends of the rear cross beam are respectively fixed to the left and right rear longitudinal beams; The inner side of the rear shock absorber tower is provided with two triangular ribs which are transitionally connected with the rounded corners of the rear longitudinal beams. The two ends of the rear cross beam are overlapped on the two rear longitudinal beams through large rounded corners respectively. The rear mounting frame of the battery box fixing frame has two L-shaped corners, and each corner has a group of bolt connection holes on both sides.

2. The lower frame of the electric vehicle according to claim 1, characterized in that: The battery box fixing frame is a rectangular frame structure, the longitudinal beam and the transverse beam of the battery box fixing frame are connected at the corners and formed in one piece, and the upper part of the corner has a large rounded corner.

3. The lower frame of the electric vehicle according to claim 2, characterized in that: The longitudinal beams and the transverse beams of the battery box fixing frame are both hollow beams with rectangular cross-sections, with a plurality of reinforcing ribs inside the beams and a plurality of openings in the middle of the outer side of the beams.

4. The lower frame of the electric vehicle according to claim 1, characterized in that: The lower shell of the battery box includes a shell body and a mounting structure. The mounting structure surrounds the shell body and is connected to the lower surface of the shell body. The mounting structure is evenly distributed with a number of through holes for connecting to the battery box fixing frame.

5. The lower frame of the electric vehicle according to claim 1, characterized in that: The battery box lower shell body is located inside the battery box fixing frame.

6. An electric vehicle chassis, characterized in that: The electric vehicle lower frame comprises the lower frame of any one of claims 1 to 5.

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