Aluminum alloy lower swing arm and method of manufacturing the same

Abstract

The application relates to the field of automobile suspensions and discloses an aluminum alloy lower swing arm which is an aluminum profile extrusion integrated structure and comprises the following parts: the upper surfaces of the main profiles are provided with outer eave parts extending to both sides; a first connecting section is formed by a first bush hole for connecting a steering knuckle being arranged at one end of the main profile along the length direction, and a second connecting section is formed by a second bush hole for connecting a vehicle frame being arranged at the other end of the main profile along the length direction; a third connecting hole for connecting a shock absorber is further arranged on the first connecting section; the main profile is gradually narrowed towards the first connecting section along the length direction and forms a pincer-shaped structure on the cross section; the main profile is gradually narrowed towards the second connecting section along the length direction and forms a U-shaped structure on the cross section, and meanwhile, the U-shaped structure is gradually narrowed upwards to form a raised bending part. The structure can effectively solve the requirement of future automobile light weight, greatly reduces the weight of parts, and guarantees the requirement of strength and durability.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automobile suspensions, in particular to an aluminum alloy lower swing arm and a manufacturing method thereof. BACKGROUND

[0002] The lower swing arm of the automobile chassis suspension is a connecting piece for forming the connection between the frame or subframe and the wheel, usually the lower swing arm is provided with three connecting ends, two of which are connected with the frame or subframe, and the other is connected with the knuckle through a ball pin. When the automobile turns, the knuckle with the wheel rotates around the lower swing arm ball pin connecting end, the lower swing arm connects the knuckle and the subframe, controls the suspension bounce, and performs parameter positioning and load transmission during movement. The commonly used lower swing arm structure is basically a stamping and welding structure of traditional materials, which is a mature process and simple to manufacture, but the traditional material itself is heavy, which will affect the shock absorption and fuel consumption when used as a vehicle material, and welding will cause loss of strength, stability and durability.

[0003] Aluminum alloy profiles are widely used in automobile parts as a common equipment manufacturing material. Aluminum alloy material is light in weight, and the density of aluminum alloy is much lower than that of steel, but the strength is relatively high; this makes the automobile parts made of aluminum alloy can significantly reduce the curb weight of the vehicle, thereby improving fuel efficiency or prolonging the cruising range of electric vehicles. Aluminum alloy has good corrosion resistance and good corrosion resistance in natural environment, can effectively resist the erosion of environmental factors such as oxidation and humidity, and prolong the service life of automobile parts. Aluminum alloy is easy to be cast, forged, extruded, cut and processed in many ways, and can be made into complex shape and high precision parts to meet the strict requirements of automobile manufacturing on the shape and precision of parts. Aluminum alloy material also has good shock absorption and heat conduction, has high damping capacity, can effectively absorb and disperse vibration, and improve ride comfort. At the same time, its good heat conduction helps the heat dissipation of engine and other hot parts, ensuring the safety and reliability of automobile operation. Aluminum alloy profiles also have recyclability and environmental protection; aluminum alloy itself is a recyclable material, and the energy consumption in the recycling process is much lower than that of extracting aluminum from primary ore. Although the initial cost of aluminum alloy may be higher than that of some traditional materials, considering the fuel efficiency improvement, maintenance cost reduction and long service life extension brought by lightweight, the overall cost is relatively high. These advantages make the use of aluminum alloy meet the current requirements of automobile industry for environmental protection and sustainable development.

[0004] However, there are still many problems in the application of aluminum alloy materials in the manufacture of automobile lower control arms, such as strength and stiffness requirements, cost, wear resistance and durability, safety and reliability considerations. As a key component of the automobile suspension system, the lower control arm needs to withstand various impact forces from the road and support the weight of the vehicle body and transmit driving force. In long-term use, it will thin out, deform and crack due to wear. Moreover, the lower control arm connector may loosen, causing the vehicle to run unstable; it is easy to rust and corrode in a humid environment, affecting its strength and stability. A faulty lower control arm can also cause abnormal noise, affecting the tranquility of driving; especially when passing through a deceleration zone or a bumpy road, the chassis noise and clearance increase phenomenon is particularly obvious. More seriously, damage to the lower control arm can also cause misalignment of the positioning parameters, causing the vehicle to deviate, and exacerbating the wear of other components, such as excessive wear of the tires. The steering system may also be affected, and even serious problems such as failure may occur. Therefore, the selection of materials and structural design of the lower control arm must have sufficient strength, stiffness, corrosion resistance and durability to cope with these complex working environments.

[0005] Aluminum alloy lower control arms are relatively rare on the market, which may be related to market acceptance and technical maturity. On the one hand, consumers' awareness and acceptance of aluminum alloy lower control arms may not be high enough; on the other hand, the manufacturing technology and process of aluminum alloy lower control arms may need to be further improved and mature. These factors may limit the widespread application of aluminum alloy lower control arms. SUMMARY

[0006] In order to solve the problems existing in the prior art, the purpose of the present application is to provide an aluminum alloy lower control arm and a manufacturing method thereof. The structure can effectively solve the requirement of lightweight of electric vehicles, and greatly reduces the weight of parts compared with the traditional stamping and welding structure. Even compared with other aluminum alloy swing arms, the aluminum alloy lower control arm of this new process also has weight advantage.

[0007] In order to achieve the above purpose, the technical scheme adopted by the present application is as follows:

[0008] An aluminum alloy lower control arm, characterized in that it comprises: the aluminum alloy lower control arm is an aluminum profile extrusion integrated structure, the upper surface of the main profile is provided with an eave part extending to both sides, and the upper surface is a plane; a first bushing hole for connecting a steering knuckle is formed on one end of the main profile along the length direction to form a first connecting section, and a second bushing hole for connecting a vehicle frame is formed on the other end to form a second connecting section; a third connecting hole for connecting a shock absorber is also formed on the first connecting section;

[0009] The main body profile gradually narrows along the length direction to the first connecting section and forms a pincer structure in cross section; the main body profile gradually narrows along the length direction to the second connecting section and forms a U-shaped structure in cross section, and the U-shaped structure gradually narrows upward to form a raised bending part.

[0010] As a further improvement of the present application, the main body profile is a rectangular tubular aluminum alloy profile.

[0011] As a further improvement of the present application, a soft pad mounting hole is formed in the central part of the upper surface of the main body profile.

[0012] As a further improvement of the present application, the first bushing hole is located in a first hollow boss part formed on the main body profile; the first hollow boss part is correspondingly arranged on both side walls.

[0013] As a further improvement of the present application, the third connecting hole is located in a second hollow boss part formed on the main body profile; the second hollow boss part is correspondingly arranged on both side walls.

[0014] As a further improvement of the present application, the bottom of the U-shaped structure of the second connecting section is extruded to form a fold.

[0015] As a further improvement of the present application, the lower part of the side wall of the main body profile is symmetrically expanded outward; the bottom of the main body profile is provided with two reinforcing protrusions in the length direction.

[0016] As a further improvement of the present application, the upper notch of the pincer structure is larger than the lower notch.

[0017] As a further improvement of the present application, the notch formed in the upper surface of the U-shaped structure is further expanded at a certain distance inward at the end and then converges to the raised bending part.

[0018] The present application relates to a manufacturing method of an aluminum alloy lower swing arm, which comprises the following steps:

[0019] The upper part of the forged main body profile forms an eaves part;

[0020] The side part of both ends of the forged main body profile forms a narrowed first connecting section and a second connecting section;

[0021] Two hollow boss parts are respectively punched inward on both side walls of the first connecting section;

[0022] A first bushing hole and a third connecting hole are respectively formed on the first hollow boss part and the second hollow boss part by drilling the main body profile; a second bushing hole is formed on both side walls of the second connecting section by drilling the main body profile; a soft pad mounting hole is formed in the central part of the upper surface of the main body profile;

[0023] Cutting the end of the first connecting section and the second connecting section respectively to form a pincer structure and a U-shaped structure;

[0024] Inner expanding the lower part of the side wall of the main profile using an inner expanding tool;

[0025] Bending the main profile at the gradually narrowing part of the second connecting section; extruding the bottom of the U-shaped structure of the second connecting section.

[0026] Compared with the prior art, the present application has the following advantages:

[0027] The present application discloses an aluminum alloy lower swing arm, which is formed by extruding an aluminum profile and is a whole piece without any extra welding structure. The first connecting section and the second connecting section are provided to facilitate connection and installation, and the overall structure is closed, effectively reducing the weight of the parts and improving the safety performance of the whole vehicle. The design of the outer eave part increases the structural strength of the lower swing arm and helps to prevent moisture, dust and other impurities from entering the interior, improving the durability of the part. The pincer structure or U-shaped structure enables the lower swing arm to more effectively disperse stress when bearing road impact force, improving the overall strength and rigidity. The pincer structure helps to increase the rigidity of the lower swing arm during steering, while the U-shaped structure provides better torsional resistance. The design of the gradually narrowing part from the main profile to both ends not only helps to reduce the weight of the lower swing arm, but also optimizes its mechanical properties, making it more stable when bearing load.

[0028] Further, the rectangular structure provides good stability and load-bearing capacity, and the lightweight properties of aluminum alloy help to reduce the overall weight of the lower swing arm. The use of rectangular tubular aluminum alloy profiles can reduce material and processing costs.

[0029] Further, the soft cushion mounting hole enables the lower swing arm to be securely connected to the lower soft cushion, ensuring the overall stability and reliability of the suspension system. The soft cushion mounting hole allows the installation of shock-absorbing soft cushions and other accessories on the lower swing arm, helping to improve the comfort and noise reduction performance of the suspension system.

[0030] Further, the design of the hollow boss part can optimize stress distribution, making the stress distribution around the connection hole more uniform, avoiding the transmission of force on the profile, increasing the strength and stability of the connection hole, and also helping to optimize the overall structure of the lower swing arm. The manufacturing of the hollow boss part through stamping process also improves the strength.

[0031] Further, the pleat design is used to increase the strength and rigidity of the bottom of the U-shaped structure, preventing deformation or damage during long-term use. The pleat design also reduces the space of the second connecting section, reducing the space for water and oil accumulation. The design of the pleat design helps to optimize the stress distribution of the second bushing hole, increasing the connection strength.

[0032] Further, the lower part of the side wall expands symmetrically outward, and the curved side wall structure can improve the bending resistance of the profile body along the length direction, and enhance the stability of the profile body under the working conditions such as crosswind or emergency lane changing.

[0033] Further, the upper notch of the pincer-shaped structure is larger than the lower notch, which provides more space for the installation of the knuckle bushing and ball pin, and also helps to optimize the mechanical properties of the lower swing arm during steering, and improve the steering sensitivity and stability.

[0034] Further, the notch formed on the upper surface of the U-shaped structure is expanded at a certain distance inward at the end and then converges at the raised bending part, and the notch design is used to optimize the stress distribution of the lower swing arm, reduce the stress concentration phenomenon under complex working conditions, and improve the durability of the component.

[0035] The application discloses a manufacturing method of an aluminum alloy lower swing arm, which comprises basic lathe machining steps such as forging, stamping, turning, drilling, cutting, internal expansion processing and extrusion. These simple basic steps help to improve the production efficiency and precision of the lower swing arm, and also help to optimize the mechanical properties and durability of the lower swing arm. Through the accurate manufacturing and processing process, the size and shape of the lower swing arm can meet the design requirements, so that the overall performance of the lower swing arm is improved. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is a schematic view of one perspective of an aluminum alloy lower swing arm;

[0037] Figure 2 is a schematic view of another perspective of an aluminum alloy lower swing arm;

[0038] Figure 3 is a schematic view of a front view of an aluminum alloy lower swing arm;

[0039] Figure 4 is a schematic view of a bottom view of an aluminum alloy lower swing arm;

[0040] 1, first bushing hole; 2, third connecting hole; 3, soft pad mounting hole; 4, second bushing hole; 5, main profile; 6, eaves part; 7, first connecting section; 8, second connecting section; 9, pincer-shaped structure; 10, U-shaped structure; 11, raised bending part; 12, first hollow boss part; 13, second hollow boss part; 14, fold; 15, reinforcing protrusion. DETAILED DESCRIPTION

[0041] To enable those skilled in the art to better understand the technical solutions of this invention, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this invention.

[0042] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only embodiments.

[0043] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0044] Example

[0045] like Figure 1 As shown, the aluminum alloy lower control arm includes: a main body profile 5, with a first bushing hole 1 for connecting the steering knuckle at one end along the length direction, forming a first connecting section 7; a second bushing hole 4 for connecting the vehicle frame at the other end, forming a second connecting section 8; a third connecting hole 2 for connecting the shock absorber; and a soft pad mounting hole 3 formed at the center of the upper surface of the main body profile 5.

[0046] The main body profile 5 is integrally formed by extruding aluminum profiles. Excess material and holes are eliminated through a blanking process, making the lower control arm a single piece, reducing the number of parts, lightening the weight of the parts, and facilitating disassembly, installation, and replacement. The first bushing hole 1 is for connecting the steering knuckle bushing and is fastened with bolts; the third connecting hole 2 is for connecting the lower end of the shock absorber and is fastened with bolts; the lower spring pad mounting hole 3 is for installing the lower spring pad, which is inserted into the mounting hole 3 by the protrusion of the lower pad; the second bushing hole 4 is for connecting the subframe and is fastened with bolts and bushings.

[0047] The aluminum alloy lower swing arm is a main component of the suspension system, located between the wheel and the subframe. The design principle of the aluminum alloy lower swing arm mainly reflects in its structural characteristics and material selection. The main profile of the aluminum alloy lower swing arm is an integrated extrusion structure, which ensures the strength and rigidity of the lower swing arm, while achieving lightweight. Through specific shape design, such as the pincer structure and U-shaped structure, as well as the lifting bending part, the aluminum alloy lower swing arm can effectively transfer the force and torque between the wheel and the vehicle body, while constraining the upward and downward movement direction of the wheel, ensuring that the tire is as close to the ground as possible. The aluminum alloy lower swing arm is connected with the steering knuckle, the frame and the shock absorber by opening the first bushing hole, the second bushing hole and the third connecting hole, thereby building a complete suspension system. This connection method not only ensures the stability and reliability of the suspension system, but also improves the handling performance and comfort of the vehicle.

[0048] The advantages are as follows: the density of aluminum alloy is relatively small, so the weight of the aluminum alloy lower swing arm is relatively light. This helps to reduce the overall weight of the vehicle, reduce the unsprung mass, and thus improve the handling performance and fuel efficiency of the vehicle. Aluminum alloy performs well in strength, which can meet the requirements of the lower swing arm for strength and rigidity. This high strength characteristic ensures the stability and reliability of the suspension system, improving the safety performance of the vehicle. Aluminum alloy has good corrosion resistance and is not prone to rust. This prolongs the service life of the lower swing arm and reduces maintenance costs. Aluminum alloy performs well in vibration absorption, which helps to reduce vibration and noise during vehicle driving and improves ride comfort. Although the raw material price of aluminum alloy is relatively high, the use of aluminum profile extrusion integrated molding technology can significantly reduce manufacturing costs and improve production efficiency.

[0049] In summary, the aluminum alloy lower swing arm has been widely used in modern automobile suspension systems due to its lightweight, high strength, good corrosion resistance and strong vibration absorption capacity. This lower swing arm not only improves the handling performance and comfort of the vehicle, but also prolongs the service life and reduces maintenance costs.

[0050] As shown in Figure 1 , the main profile 5 upper part is provided with an outer eave part 6 extending to both sides, and the upper surface is a plane; the upper surface of the main profile 5 is provided with a soft pad mounting hole 3 in the center part, and the spring lower soft pad mounting hole 3 is used to install the spring lower soft pad. The protrusion of the lower soft pad is inserted into the mounting hole 3, which has elasticity and is convenient for installation and adjustment.

[0051] As shown in Figure 2As shown, the main profile 5 gradually narrows in the length direction to the first connecting section 7 and forms a pincer structure 9 in the cross section; the main profile 5 gradually narrows in the length direction to the second connecting section 8 and forms a U-shaped structure 10 in the cross section, and the U-shaped structure 10 gradually narrows upward to form a raised bending part 11. The gradual narrowing is naturally formed by extrusion on both sides without increasing the complex manufacturing process. The raised bending part is also bent by a bending machine or a punch, without increasing the complex process.

[0052] The main profile 5 is made of aluminum alloy profile and is integrally formed, reducing the number of parts; the hollow material reduces the weight of the structure.

[0053] The pincer structure 9 or the U-shaped structure 10 enables the swing arm to more effectively disperse stress when bearing the impact force of the road surface, improving the overall strength and rigidity; the pincer structure 9 helps to increase the rigidity of the swing arm when turning, and the U-shaped structure 10 can provide better torsional resistance; the design of gradually narrowing from the main profile to both ends not only helps to reduce the weight of the swing arm, but also optimizes its mechanical properties, making it more stable when bearing load.

[0054] The first bushing hole 1 is located in the first hollow boss part 12 formed on the main profile 5; the first hollow boss part 12 is correspondingly arranged inwardly protruding on both side walls. The third connecting hole 2 is located in the second hollow boss part 13 formed on the main profile 5; the second hollow boss part 13 is correspondingly arranged inwardly protruding on both side walls. The design of the hollow boss part can optimize the stress distribution, make the stress distribution around the connecting hole more uniform, avoid the transmission of force on the profile, increase the strength and stability of the connecting hole, and also help to optimize the overall structure of the swing arm; the hollow boss part is manufactured by stamping process, which also improves the strength.

[0055] As shown, Figure 3 The first bushing hole 1 is located in the first hollow boss part 12 formed on the main profile 5; the first hollow boss part 12 is correspondingly arranged inwardly protruding to facilitate the alignment and installation of the bushing.

[0056] Similarly, the third connecting hole 2 is located in the second hollow boss part 13 formed on the main profile; the second hollow boss part is correspondingly arranged inwardly protruding to facilitate the alignment and installation of the bolt with the shock absorber.

[0057] The U-shaped structure bottom of the second connecting section 8 is extruded to form a fold 14, which helps to optimize the stress distribution of the second bushing hole 4 and increase the connecting strength.

[0058] As shown, Figure 4As shown, the lower part of the side wall of the main profile 5 is symmetrically expanded outward, and during manufacturing, an internal expansion tool can be used, with appropriate size, inserted into the aluminum alloy profile, and operated according to the requirements of internal expansion processing until the desired aperture and shape are achieved, so as to improve the quality and performance of the aluminum profile. The bottom of the main profile 5 is provided with two reinforcing protrusions 15 along the length direction of the outer contour, for reinforcing and supporting the structure.

[0059] The upper notch of the pincer-shaped structure 9 is larger than the lower notch; the notches can be completed by turning and cutting processes; such design leaves more space for the installation of the knuckle bushing and ball pin, and also helps to optimize the mechanical properties of the lower swing arm during steering, improve the sensitivity and stability of steering. In addition, the notch design also further reduces the weight of the lower swing arm.

[0060] The notch formed on the upper surface of the U-shaped structure is expanded at a certain distance inward at the end and then converges at the raised bending part, and such unique notch design is used to optimize the stress distribution of the lower swing arm, reduce the stress concentration phenomenon under complex working conditions, and improve the durability of the component; the weight of the cut-out notch is also further reduced without reducing the strength.

[0061] The manufacturing method of the aluminum alloy lower swing arm in the application comprises the following steps:

[0062] The upper part of the forged main profile 5 forms the eaves part 6;

[0063] The side part of the two ends of the forged main profile 5 forms the narrowed first connecting section 7 and the second connecting section 8;

[0064] Two hollow boss parts 12 and 13 are respectively punched inward on the two side walls of the first connecting section 7;

[0065] The first bushing hole 1 and the third connecting hole 2 are respectively formed by drilling the main profile 5 on the first hollow boss part 12 and the second hollow boss part 13; the second bushing hole 4 is formed by drilling the main profile 5 on the two side walls of the second connecting section 8; the soft pad mounting hole 3 is formed by drilling the center part of the upper surface of the main profile 5;

[0066] The end part of the first connecting section 7 and the second connecting section 8 is respectively cut to form the pincer-shaped structure 9 and the U-shaped structure 10;

[0067] The lower part of the side wall of the main profile 5 is internally expanded by using an internal expansion tool;

[0068] The main profile 5 is bent at the gradually narrowing part of the second connecting section 8; the fold 14 is formed by extruding the bottom of the U-shaped structure 20 of the second connecting section 8; the two reinforcing protrusions 15 are formed by extruding the bottom of the main profile 5 along the length direction of the outer contour.

[0069] The present invention discloses a manufacturing method of an aluminum alloy lower swing arm, which comprises the lathe processing steps of forging, stamping, turning, drilling, cutting, internal expansion processing and extrusion. These simple basic steps do not increase the high manufacturing cost, but can improve the production efficiency and precision of the lower swing arm, and also help to optimize its mechanical properties and durability. Through the accurate manufacturing and processing process, the size and shape of the lower swing arm can be ensured to meet the design requirements, so as to improve its overall performance.

[0070] Many embodiments and many applications other than those described herein will be apparent to those skilled in the art from consideration of the specification and practice of the teachings herein. Thus, the scope of the present teachings should not be limited to the specific examples described herein, but should be given the full scope of the appended claims and any equivalents thereof. For purposes of the US, this application claims priority to U.S. Provisional Patent Application No. 62 / 978, 1 10, filed February 15, 2020, the entire disclosure of which is incorporated by reference herein. All articles and references, including patent applications and publications, are hereby incorporated by reference for all purposes. Any statements as to the manner of operation or implementation of the subject matter, or of the preferred embodiments, are intended merely as illustrative and are not to be taken as limiting.

[0071] The above is a further detailed description of the present invention, which cannot be considered as limiting the specific embodiments of the present invention to the above, and for those skilled in the art, without departing from the concept of the present invention, a number of simple deductions or replacements can also be made, which should be considered as belonging to the present invention. The scope of protection is determined by the claims submitted.

Claims

1. An aluminum alloy lower swing arm characterized by, The aluminum alloy lower swing arm is an aluminum profile extrusion integrated structure, comprising a main profile (5); The upper part of the main profile (5) is provided with an eaves part (6) extending to both sides, and the upper surface is a plane; The main profile (5) is provided with a first bushing hole (1) for connecting a knuckle at one end along the length direction to form a first connecting section (7), and a second bushing hole (4) for connecting a frame at the other end to form a second connecting section (8); The first connecting section (7) is further provided with a third connecting hole (2) for connecting a shock absorber; The main profile (5) is gradually narrowed along the length direction to the first connecting section (7) and forms a pincer-shaped structure (9) on the cross section; The main profile (5) is gradually narrowed along the length direction to the second connecting section (8) and forms a U-shaped structure (10) on the cross section, and the U-shaped structure (10) is gradually narrowed upward to form a raised curved part (11); The main profile (5) is a rectangular tubular aluminum alloy profile; The U-shaped structure (10) of the second connecting section (8) is extruded to form a fold (14) at the bottom; The lower part of the side wall of the main profile (5) is symmetrically expanded outward; The bottom of the main profile (5) is provided with two reinforcing protrusions (15) along the length direction on the outer contour; The U-shaped structure (10) forms a notch on the upper surface, which is enlarged at a certain distance inward at the end and then converges to the raised curved part (11).

2. The aluminum alloy lower swing arm of claim 1, wherein The main profile (5) is provided with a soft pad mounting hole (3) at the center of the upper surface.

3. The aluminum alloy lower swing arm of claim 1, wherein The first bushing hole (1) is located in the first hollow boss part (12) formed on the main profile (5); The first hollow boss part (12) is correspondingly arranged inwardly protruding on both side walls.

4. The aluminum alloy lower swing arm of claim 1, wherein The third connecting hole (2) is located in the second hollow boss part (13) formed on the main profile (5); The second hollow boss part (13) is correspondingly arranged inwardly protruding on both side walls.

5. The aluminum alloy lower swing arm of claim 1, wherein The upper notch of the pincer-shaped structure (9) is larger than the lower notch.

6. A manufacturing method of the aluminum alloy lower swing arm according to any one of claims 1-5, comprising the following steps: Forging and pressing the upper part of the main profile (5) to form the eaves part (6); Forging and pressing the side parts of both ends of the main profile (5) to form the narrowed first connecting section (7) and the second connecting section (8); Respectively punching two hollow boss parts inwardly on both side walls of the first connecting section (7); Respectively drilling the first bushing hole (1) and the third connecting hole (2) in the first hollow boss part (12) and the second hollow boss part (13) of the main profile (5); Drilling the second bushing hole (4) in both side walls of the second connecting section (8) of the main profile (5); Drilling the soft pad mounting hole (3) in the center of the upper surface of the main profile (5); Respectively cutting the end part of the first connecting section (7) and the second connecting section (8) to form the pincer-shaped structure (9) and the U-shaped structure (10); Using an internal expansion tool to internally expand the lower part of the side wall of the main profile (5); Bending the main profile (5) at the gradually narrowing part of the second connecting section (8); Extruding the bottom of the U-shaped structure (10) of the second connecting section (8) to form a fold (14).

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