Rear auxiliary frame assembly of vehicle

Abstract

The invention provides a rear auxiliary frame assembly of a vehicle, and relates to the technical field of rear auxiliary frames of vehicles, the rear auxiliary frame assembly of the vehicle comprises a square framework, the square framework comprises a front cross beam, a rear cross beam and two longitudinal beams, the two longitudinal beams are arranged at intervals and are connected with the front cross beam and the rear cross beam respectively to form a closed frame structure, the front cross beam is provided with a front suspension support, the rear cross beam is provided with a rear suspension support, the two longitudinal beams are respectively provided with a front suspension support, the front cross beam and the two longitudinal beams are all tubular beam pieces, and the rear cross beam is a metal plate welding component; and the node reinforcing structures are arranged at at least one connecting node of the longitudinal beams and the front cross beam and / or the rear cross beam, and are used for connecting the corresponding longitudinal beams and the front cross beam and / or the rear cross beam, so that a closed-loop stress structure supported by a triangle is formed at the connecting node. The rear auxiliary frame assembly has the effects that the overall and local rigidity of the rear auxiliary frame assembly is remarkably improved, the stress concentration and fatigue risk are reduced, and the whole vehicle NVH and assembly consistency are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of rear subframe of vehicle, and particularly relates to a rear subframe assembly of vehicle. BACKGROUND

[0002] The rear subframe (also known as rear axle subframe or rear suspension subframe) is usually one of the core load-bearing structures of the vehicle chassis, and is used to provide a solid, accurate and stable mounting base for key components of the rear suspension system (such as tie rods, knuckles, stabilizer bars, spring arms, etc.), and to connect the dispersed suspension hard points as a whole, thereby improving the torsional stiffness and bending stiffness of the rear part of the vehicle body and ensuring the handling stability and positioning accuracy of the vehicle.

[0003] With the development of electric vehicles (pure electric, extended range, plug-in hybrid) and rear-drive vehicles, the rear subframe not only needs to bear the suspension load, but also needs to provide mounting stiffness for the drive motor / power unit. Due to the fast start-up acceleration and large instantaneous torque of the motor, the torque reaction will induce torsion and vibration of the rear suspension assembly. If the stiffness of the rear subframe is insufficient, it will easily cause fluctuations in wheel positioning parameters, enhanced vibration and noise transmission, and thus affect the handling and NVH (noise, vibration, harshness) performance of the vehicle.

[0004] The existing rear subframe mainly includes the following structure forms and manufacturing processes: H-shaped or mouth-shaped frame structure formed by welding upper and lower plates of a stamped sheet metal part, square steel / wrought steel welded structure, tubular beam frame structure, and aluminum alloy die-casting integrated structure, etc. Among them, the sheet metal stamping and welding scheme usually has many welds, a complex structure and a large mass; the torsional stiffness and mass utilization rate of the square steel / wrought steel structure are limited, and additional reinforcing members and multiple welds are often needed, resulting in increased mass; although the tubular beam frame is beneficial to simplify part of the structure, it often needs to add additional cross beams or supports to meet the complete connection with the vehicle body, the arrangement requirements of the steering gear / stabilizer bar, etc., which is not conducive to structure simplification and comprehensive performance.

[0005] From the perspective of cost and mass production, some existing subframes are complex in structure, heavy in weight, and have high development cost of complete tooling due to the limitations of processing technology and forming materials; at the same time, some schemes mainly use rigid connection, which results in large vibration transmission and insufficient vibration absorption capacity.

[0006] Another technical scheme configures multiple installation supports in different areas to adapt to the stress state of the multi-link suspension, but since the stress of each part of the rear subframe is obviously different, if the same type or a large number of supports are used to meet the load-bearing requirements, it may still cause problems such as heavy structure and high manufacturing cost.

[0007] In order to reduce the weight and the mold cost, there is also a rear subframe scheme of "pipe + sheet metal tailor-welding" in the industry, but such a scheme may have problems of insufficient overall stiffness, low strength and NVH performance under some vehicle models and high load working conditions, and the application scene is limited.

[0008] In addition, even if a square skeleton frame structure composed of longitudinal beams and cross beams is adopted, the torsional stiffness and torsional mode may be low due to insufficient local stiffness at key nodes such as frame joints, thereby causing strength and NVH risks.

[0009] Therefore, in the design of the rear subframe structure, how to achieve a comprehensive balance between high stiffness, high strength, low weight, high production efficiency and low cost while meeting the requirements of rear suspension hard point precision and power unit installation stiffness is still a technical problem to be solved by those skilled in the art. SUMMARY

[0010] In order to improve the above technical problems, the present application provides a rear subframe assembly of a vehicle.

[0011] The rear subframe assembly of a vehicle provided by the present application adopts the following technical scheme: A rear subframe assembly of a vehicle, comprising: a skeleton comprising a front cross beam, a rear cross beam and two longitudinal beams, the two longitudinal beams being arranged at intervals and connected with the front cross beam and the rear cross beam respectively to form a closed frame structure; a node reinforcing structure arranged at at least one connecting node of the longitudinal beam and the front cross beam and / or the rear cross beam, for connecting the corresponding longitudinal beam with the front cross beam and / or the rear cross beam to form a triangularly supported closed loop stress structure at the connecting node.

[0012] Further, the first end of the longitudinal beam is connected with the side wall of the front cross beam, the two ends of the rear cross beam are respectively connected with the side walls of the two longitudinal beams, the two ends of the front cross beam protrude from the longitudinal beams to form two front mounting point areas, and the second ends of the two longitudinal beams protrude from the rear cross beam as two rear mounting point areas, the front mounting point areas are provided with front mounting sleeves for connecting the vehicle body, and the rear mounting point areas are provided with rear mounting sleeves for connecting the vehicle body.

[0013] Further, the node reinforcing structure comprises a front reinforcing pipe and a rear reinforcing pipe, the front reinforcing pipe and the rear reinforcing pipe are arranged on the outer side of the skeleton, the front reinforcing pipe is used for connecting the front cross beam and the longitudinal beam, and the rear reinforcing pipe is used for connecting the rear cross beam and the two longitudinal beams.

[0014] Further, the front cross beam has a smaller diameter than the front mounting sleeve, the longitudinal beam has a larger diameter than the rear mounting sleeve, and the front mounting sleeve and the rear mounting sleeve have the same diameter; Further, the mounting point reinforcement is connected to the front cross beam, one end of the front reinforcement tube is connected to the corresponding longitudinal beam, and the other end is connected to the mounting point reinforcement, the end of the front cross beam is provided with a first contoured cut edge area, and the mounting point reinforcement cooperates with the first contoured cut edge area to form a partial surrounding support structure on the side of the front mounting sleeve. The second end of the longitudinal beam is provided with a second contoured cut edge area to form a partial surrounding support structure on the side of the rear mounting sleeve.

[0015] Further, the two ends of the front cross beam and the second end of the longitudinal beam are each provided with a shaping section, the first contoured cut edge area is arranged on the corresponding shaping section of the front cross beam, the second contoured cut edge area is arranged on the corresponding shaping section of the longitudinal beam, the cross section of the shaping section transitions from a circular shape to a square or approximately square shape, the cross section of the rear reinforcement tube is square or approximately square, and the cross section of the front reinforcement tube is circular or approximately circular.

[0016] Further, the rear cross beam includes an inner plate and an outer plate connected to each other, a cavity is formed between the inner plate and the outer plate, and a cavity reinforcement is arranged in the cavity at the connection between the rear cross beam and the rear reinforcement tube, and the cavity reinforcement is connected to the inner plate and the outer plate.

[0017] Further, the rear cross beam is provided with two spring arm mounting seats, the two spring arm mounting seats are arranged on the rear cross beam in a spaced manner along the length direction of the rear cross beam, and the rear subframe assembly is provided with a support member around the two spring arm mounting seats, and the support member cooperates with the rear cross beam and the longitudinal beam.

[0018] Further, the support member includes a transverse support tube and a longitudinal support tube. The transverse support tube is connected between the two spring arm mounting seats. One end of the longitudinal support tube is connected to the transverse support tube, and the other end is connected to the longitudinal beam. The structure of the transverse support tube, the longitudinal support tube, the corresponding section of the longitudinal beam, and the rear cross beam in the spring arm mounting seat region together form at least one closed load transfer loop.

[0019] Further, a connection reinforcement is arranged between the rear cross beam and the transverse support tube, and the connection reinforcement is arranged between the two spring arm mounting seats.

[0020] Further, the longitudinal support pipe is provided with a hole expansion or diameter expansion structure at the end connected with the longitudinal beam to increase the connection area.

[0021] In summary, the present application includes at least one of the following beneficial technical effects: 1. By constructing a closed framework surrounded by a front cross beam, a rear cross beam and two longitudinal beams, and setting a node reinforcement structure at the connection node of the longitudinal beam and the front cross beam and / or the rear cross beam, a closed loop stress structure of triangular support is formed at the node, thereby establishing an additional load transfer path outside the main load-bearing frame, solving the problems of weak torsion, stress concentration and obvious vibration transmission at the key node of the traditional rear subframe, and achieving the effects of improving overall torsional stiffness, reducing structural vibration response, and improving vehicle NVH and durability reliability; 2. By setting a front mounting sleeve and a rear mounting sleeve in the front mounting point area and the rear mounting point area respectively, and combining the pipe diameter matching relationship of the front cross beam / longitudinal beam and the mounting sleeve, at the same time setting a mounting point reinforcement between the front mounting sleeve and the front cross beam and cooperating with the first follow-up trimming area to form a partial surrounding support structure for the sleeve peripheral side, and setting a second follow-up trimming area at the end of the longitudinal beam to form a partial surrounding support structure for the rear mounting sleeve, the fatigue risk problem caused by insufficient overlap length, low local stiffness and concentrated weld load in the mounting point area is solved, and the effects of increasing the contact area and the effective length of the weld, improving the local stiffness and fatigue life of the mounting hard point, and improving the assembly precision and consistency are achieved; 3. By designing the rear cross beam as a cavity structure surrounded by an inner plate and an outer plate, and setting a cavity reinforcement in the cavity corresponding to the connection between the rear cross beam and the rear reinforcement pipe, the cavity reinforcement is connected with the inner plate and the outer plate at the same time, and a load transfer path is established inside the rear cross beam, solving the problems of local buckling, weld fatigue and insufficient stiffness caused by concentrated load input of the rear reinforcement pipe to the single-sided plate, and achieving the effects of improving the anti-deformation ability of the connection area, improving the load dispersion efficiency and enhancing the connection reliability of the rear cross beam; 4. By setting two spring arm mounting seats on the rear cross beam, and setting a support member composed of a transverse support pipe and a longitudinal support pipe around it, the transverse support pipe, the longitudinal support pipe, the corresponding section of the longitudinal beam and the rear cross beam form a closed load transfer loop together, and the closed loop is divided into at least two local closed loops by setting a connection reinforcement between the rear cross beam and the transverse support pipe, and a hole expansion or diameter expansion structure is set at the connection end of the longitudinal support pipe and the longitudinal beam to increase the connection area, solving the problems of stress concentration and connection fatigue caused by insufficient local stiffness of the spring arm load input point and single load path, and achieving the effects of strengthening the local stiffness of the spring arm area, improving the load diversion and transmission efficiency, reducing the unit load of the weld, and improving the durability reliability of the area. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0023] Figure 1 is a schematic diagram of a square skeleton structure of an embodiment of the present application.

[0024] Figure 2 is a schematic diagram of the structure of the front and rear suspension supports of an embodiment of the present application.

[0025] Figure 3 is a sectional view of the rear cross beam of an embodiment of the present application.

[0026] Figure 4 is a schematic diagram of the overall structure of the node reinforcement structure of an embodiment of the present application.

[0027] Figure 5 is a schematic diagram of the local structure of the node reinforcement structure of an embodiment of the present application.

[0028] Figure 6 is a height comparison perspective view of the mounting sleeve and the front and rear cross beams of an embodiment of the present application.

[0029] Figure 7 is a schematic diagram of the mounting position of the cavity reinforcement of an embodiment of the present application.

[0030] Figure 8 is a schematic diagram of the mounting position of the spring arm mounting seat of an embodiment of the present application.

[0031] Figure 9 is a schematic diagram of the structure of the support member of an embodiment of the present application.

[0032] Figure 10 is a side view schematic diagram of the support member of an embodiment of the present application.

[0033] Figure 11 is a schematic diagram of the structure of the connection reinforcement of an embodiment of the present application.

[0034] Figure 12 is a lateral schematic diagram of the connection reinforcement of an embodiment of the present application.

[0035] Figure 13 is a schematic diagram of the overall structure of an embodiment of the present application.

[0036] Reference numerals: 1. Front crossbeam; 2. Rear crossbeam; 21. Inner plate; 22. Outer plate; 23. Rear suspension bracket; 24. Rear suspension main body; 25. Cavity reinforcement; 3. Longitudinal beam; 31. Front suspension bracket; 32. Front suspension main body; 4. Node reinforcement structure; 41. Front reinforcing tube; 42. Rear reinforcing tube; 43. Mounting point reinforcement; 5. Front mounting sleeve; 6. Rear mounting sleeve; 7. Spring arm mounting seat; 8. Support component; 81. Transverse support tube; 82. Longitudinal support tube; 83. Connecting reinforcement; 91. First mounting bracket; 92. Second mounting bracket; 93. Third mounting bracket; 94. Fourth mounting bracket; 95. Fifth mounting bracket. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0038] This application discloses a rear subframe assembly for a vehicle. As a crucial load-bearing component of the vehicle chassis system, the rear subframe assembly provides a mounting base for the suspension system and related powertrain components, and reliably transmits impact loads, suspension loads, and dynamic loads from the road surface to the vehicle body structure.

[0039] To simultaneously consider structural stiffness, strength, lightweight, manufacturing efficiency, and cost control, this embodiment adopts a hybrid structural form with "tube beam components as the main component and sheet metal welded components as the auxiliary component": a closed frame mainly composed of tube beam components serves as the main load-bearing frame, and node reinforcement structures 4 are arranged at key nodes prone to stress concentration and torsional weakness; at the same time, in key load input areas such as the rear crossbeam 2 and spring arm mounting seat 7, a locally closed load transfer loop is further constructed, thereby improving the overall torsional stiffness, local load-bearing capacity, and NVH performance of the rear subframe assembly without significantly increasing weight and process complexity.

[0040] Specifically, such as Figure 1 , Figure 2 As shown, the rear subframe assembly includes a frame. The frame includes a front crossbeam 1, a rear crossbeam 2, and two longitudinal beams 3. The two longitudinal beams 3 are spaced apart, and the front ends of the two longitudinal beams 3 are connected to the front crossbeam 1, and the rear ends of the two longitudinal beams 3 are connected to the rear crossbeam 2, thereby enclosing and forming a closed frame structure.

[0041] Furthermore, the front crossbeam 1, the two longitudinal beams 3, and the rear crossbeam 2 together form a square frame. In a specific embodiment, such as... Figure 2As shown, two longitudinal beams 3 are spaced apart in the left-right direction. The first end of each longitudinal beam 3 is connected to the side wall of the front crossbeam 1, and both ends of the rear crossbeam 2 are connected to the side walls of the two longitudinal beams 3 respectively, thereby forming a closed frame structure with the front crossbeam 1, the rear crossbeam 2, and the two longitudinal beams 3. Furthermore, the side wall connection can preferably be achieved by lap welding, that is, the ends of the longitudinal beams form an lap area with the side walls of the front / rear crossbeams and are welded and fixed to obtain a larger effective weld length and improve the overall stiffness of the connection node, thereby reducing stress concentration at the node and improving fatigue reliability.

[0042] To create mounting hard points for connection to the vehicle body and provide a stable load-bearing area for the sleeve arrangement, the two ends of the front crossbeam 1 protrude from the longitudinal beam 3, thus forming two front mounting point areas; the second ends of the two longitudinal beams 3 protrude from the rear crossbeam 2, thus forming two rear mounting point areas. By arranging the mounting point areas as the end areas of a relatively square frame extending outwards, the vehicle body connection load can be more directly introduced into the main force transmission path of the closed frame, while reserving sufficient space for assembling fasteners and bushing assemblies, improving assembly accessibility and positioning stability.

[0043] Furthermore, a front mounting sleeve 5 for connecting to the vehicle body is provided in the front mounting point area, and a rear mounting sleeve 6 for connecting to the vehicle body is provided in the rear mounting point area. The front mounting sleeve 5 and the rear mounting sleeve 6 are preferably cylindrical metal sleeve structures, axially used to accommodate vehicle body connecting fasteners and / or bushing assemblies, and fixed to the corresponding front and rear mounting point areas by welding. In alternative embodiments, the front / rear mounting sleeve can also be implemented as a sleeve seat, bushing seat, or mounting hole seat with through holes. Therefore, by providing mounting sleeves in the front and rear mounting point areas respectively, stable vehicle body connection hard points can be formed, allowing the load to be distributed more evenly in the circumferential direction of the sleeve, thereby improving the local rigidity and assembly consistency of the mounting point area.

[0044] Furthermore, both the front crossbeam 1 and the two longitudinal beams 3 are tubular beam structures. The tubular beams are preferably made of metal tubing with a circular or near-circular cross-section, which can be mass-produced through processes such as bending, trimming, and shaping, simplifying the manufacturing process and ensuring stable quality. Moreover, the circular or near-circular cross-section has a better structural advantage in terms of torsional resistance, which is beneficial to improving the torsional resistance of the square frame foundation.

[0045] On the other hand, the rear crossbeam 2 is a sheet metal welded component. The rear crossbeam 2 is formed by welding sheet metal stamping parts, which facilitates the integration of larger cross-sectional dimensions and local reinforcement structures. It is suitable for arranging installation structures that require high rigidity and spatial arrangement freedom, such as the rear suspension bracket 23 and the spring arm mounting seat 7, in the area of ​​the rear crossbeam 2.

[0046] To achieve a reliable connection between the rear subframe assembly and the suspension and powertrain components, such as Figure 2 , Figure 3 As shown, a rear suspension bracket 23 is provided on the rear crossbeam 2 for mounting the rear suspension body 24 or for mounting and connecting to power system components such as the rear drive motor / rear axle; front suspension brackets 31 are provided on the two longitudinal beams 3 for mounting the front suspension body 32 or for connecting to corresponding hardpoints on the vehicle body. By partitioning the longitudinal beams 3 and the rear crossbeam 2 with front suspension brackets 31 and rear suspension brackets 23, a reasonable force transmission path can be formed within the frame to reduce the local peak stress of a single beam.

[0047] like Figure 3 As shown, the rear crossbeam 2 includes an inner plate 21 and an outer plate 22 that are connected to each other, forming a cavity between the inner plate 21 and the outer plate 22. By welding the inner plate 21 and the outer plate 22 to form a cavity structure, the cross-sectional moment of inertia and torsional resistance of the rear crossbeam 2 can be increased under the condition of limited plate thickness, providing a more stable structural foundation for the rear suspension bracket 23, the spring arm mounting seat 7, and the rear mounting point area.

[0048] To further enhance the resistance to local buckling of the rear crossbeam 2 near the load input point, the inner plate 21 and the outer plate 22 can form folded edges, flanges, or local rib structures in the corresponding areas; and the cavity structure can provide a spatial basis for the subsequent arrangement of reinforcing members inside the cavity, so that the rear crossbeam 2 can not only rely on welding on the outer surface, but also achieve load dispersion and closed-loop transmission through force transmission inside the cavity.

[0049] Thus, the rear crossbeam 2 can improve local stiffness and torsional performance without significantly increasing weight, and create conditions for load diversion in critical connection areas.

[0050] Although the skeleton can form a basic closed frame, torsional weak areas may still form at the connection nodes between the front crossbeam 1 and the longitudinal beam 3, and between the rear crossbeam 2 and the longitudinal beam 3, due to geometric abrupt changes and weld concentration. Therefore, as... Figure 4 As shown, a node reinforcement structure 4 is provided at at least one connection node between the longitudinal beam 3 and the front crossbeam 1 and / or the rear crossbeam 2.

[0051] The node reinforcement structure 4 is used to connect the corresponding longitudinal beam 3 to the front crossbeam 1 and / or the rear crossbeam 2, thereby forming a triangular support closed-loop load-bearing structure at the connection node. This triangular closed-loop structure can provide a second force transmission path for the node area, enabling load to be distributed and transferred at the node, avoiding excessive load on a single weld or a single beam, thereby improving the torsional stiffness and fatigue reliability of the node.

[0052] Therefore, the node reinforcement structure 4 can effectively improve the stiffness and modal level of key nodes of the square frame, reduce the transmission of structural vibration and noise to the vehicle body, and improve NVH performance.

[0053] Specifically, such as Figure 5 As shown, the node reinforcement structure 4 may include a front reinforcement tube 41 and a rear reinforcement tube 42, both of which are located on the outer side of the frame. The front reinforcement tube 41 is used to connect the front crossbeam 1 and the longitudinal beam 3, and the rear reinforcement tube 42 is used to connect the rear crossbeam 2 and the longitudinal beam 3, thereby forming a triangular closed loop at the corresponding node.

[0054] To balance ease of processing and assembly with localized fit strength, the front reinforcing tube 41 is preferably a circular or near-circular cross-section tube, which has advantages in angle adaptation and welding accessibility; the rear reinforcing tube 42 is preferably a square or near-square cross-section tube, which is more conducive to forming a stable fit with the flat welding plane of the rear crossbeam 2 and the rear installation point area, thereby increasing the overlap area and the effective length of the weld.

[0055] Therefore, by strategically configuring reinforcing tubes with different cross-sectional shapes at different nodes, the load-bearing efficiency and reliability of the node closed-loop structure can be improved while ensuring manufacturing feasibility.

[0056] Furthermore, in the front mounting point area, a mounting point reinforcement 43 is provided between the front mounting sleeve 5 and the front crossbeam 1. The mounting point reinforcement 43 is preferably a plate-shaped or bent plate-shaped structure, with one side connected to the end of the front crossbeam 1 and the other side connected to the outer periphery of the front mounting sleeve 5, thereby forming a transition support structure between the front mounting sleeve 5 and the front crossbeam 1.

[0057] In addition, the mounting point reinforcement 43 can also serve as the connection end of the node closed-loop structure, and be used to connect with the front reinforcement tube 41, so that the load in the front mounting point area can be more directly introduced into the triangular closed-loop force path formed by "front crossbeam 1-longitudinal beam 3-front reinforcement tube 41", further improving the collaborative bearing capacity of the node and mounting point areas and improving NVH performance.

[0058] In some embodiments, one side of the rear reinforcing tube 42 is connected to the rear crossbeam 2. Since the rear crossbeam 2 is a sheet metal welded component, it can provide a relatively flat welding surface, enabling a stable welded connection between the rear reinforcing tube 42 and the rear crossbeam 2; the other side of the rear reinforcing tube 42 is connected to the rear mounting sleeve 6. To ensure the assembly reference height and positioning accuracy of the rear mounting sleeve 6, the welded parts near the sleeve usually need to be offset in height, so that their height is lower than or not higher than the reference height of the sleeve, in order to avoid pressure or interference on the positioning of the sleeve during assembly.

[0059] Based on the above requirements for high matching and fit, such as Figure 6As shown, the longitudinal beam 3 has a shaping section in the connection area with the rear-mounted sleeve 6. The cross-section of the shaping section transitions from a circle to a square or approximately square, so that the end of the longitudinal beam 3 forms a non-circular cross-section with a planar contact surface. On the one hand, the non-circular cross-section helps to increase the overlap area and weld length between the longitudinal beam 3 and the rear-mounted sleeve 6; on the other hand, the non-circular cross-section facilitates stable positioning and height control in the fixture, thereby improving assembly consistency.

[0060] Therefore, by combining the design of "rear crossbeam 2 plane welding + sleeve reference height control + longitudinal beam 3 end shaping", the connection strength and durability reliability of the rear mounting point area can be improved while ensuring assembly accuracy.

[0061] In some implementations, to standardize the specifications of bushings and fasteners at the front and rear mounting points, and to consider the local rigidity of the mounting point area while ensuring assembly space, such as Figure 6 As shown, the front mounting sleeve 5 and the rear mounting sleeve 6 have the same diameter, so that the front and rear mounting points can use the same specifications of bushing assemblies and connecting fasteners, thereby reducing the types of parts and improving assembly consistency.

[0062] Furthermore, the diameter of the front crossbeam 1 is smaller than the diameter of the front mounting sleeve 5. By making the diameter of the front crossbeam 1 relatively small, on the one hand, more space can be reserved for the front mounting sleeve 5 and its circumferential welding overlap, so that the front mounting sleeve 5 forms a more stable transition connection at the end of the front crossbeam 1; on the other hand, the weight of the front crossbeam 1 can be reduced while meeting the strength requirements, which is beneficial to the overall lightweight design.

[0063] On the other hand, the diameter of the longitudinal beam 3 is larger than the diameter of the rear-mounted sleeve 6. By making the diameter of the longitudinal beam 3 relatively large, the local cross-sectional stiffness and bending and torsional resistance of the longitudinal beam 3 as the main force transmission component can be improved, and the longitudinal beam 3 can provide more sufficient load-bearing support for the rear-mounted sleeve 6 in the rear-mounting point area, which is beneficial to reducing local stress concentration at the rear-mounting point and improving fatigue reliability.

[0064] Therefore, by combining the configuration of "the diameter of the front crossbeam 1 is smaller than the diameter of the front mounting sleeve 5, the diameter of the longitudinal beam 3 is larger than the diameter of the rear mounting sleeve 6, and the front and rear mounting sleeves are of the same diameter", it is possible to achieve a reasonable structural transition in the mounting point area and smoother load transfer while unifying the assembly specifications. This improves the local rigidity and assembly consistency of the mounting point area and enhances the NVH performance of the entire vehicle.

[0065] In some implementations, to increase the overlap area at the connection between the mounting sleeve and the pipe beam and reduce stress concentration, such as Figure 5As shown, the end of the front crossbeam 1 is provided with a first conformal cut edge region, which is located at the end of the corresponding shaping section of the front crossbeam 1. The first conformal cut edge region is a cut edge or notch provided along the outer periphery of the front mounting sleeve 5, and its shape is adapted to the outer periphery of the front mounting sleeve 5, so that the end of the front crossbeam 1 can form a fitting clearance and circumferential covering space for the front mounting sleeve in this region.

[0066] Furthermore, since the diameter of the front crossbeam 1 is smaller than that of the front mounting sleeve 5, a mounting point reinforcement 43 is provided between the front mounting sleeve 5 and the front crossbeam 1. The mounting point reinforcement 43 mates with the first conformal cut edge area. Specifically, one side of the mounting point reinforcement 43 is connected to the end of the front crossbeam 1, and the other side is connected to the outer periphery of the front mounting sleeve 5. Together with the first conformal cut edge area, it forms a partially enclosing support structure around the periphery of the front mounting sleeve 5, so that the front mounting sleeve 5 is supported by the end of the front crossbeam 1 and the mounting point reinforcement 43 in at least a portion of the circumferential direction. Through the above-mentioned partially enclosing support structure, the welding lap length between the front mounting sleeve 5 and the front crossbeam 1 / mounting point reinforcement 43 can be significantly increased, allowing the vehicle body connection load to be distributed more evenly in the circumferential direction of the sleeve, thereby reducing the unit load of the weld, improving the local stiffness and fatigue reliability of the front mounting point area, and improving the structural vibration transmission characteristics.

[0067] In the rear mounting point area, such as Figure 5 As shown, the second end of the longitudinal beam 3 is provided with a second conformal cut edge region, which is located at the end of the corresponding shaped section of the longitudinal beam 3. The second conformal cut edge region is also a conformal cut edge or notch provided along the outer periphery of the rear mounting sleeve 6. Its shape is adapted to the outer periphery of the rear mounting sleeve 6, allowing the second end of the longitudinal beam 3 to form a fitting and covering space around the rear mounting sleeve 6, thus constituting a partial surrounding support structure around the rear mounting sleeve 6. Through the conformal fitting of the second conformal cut edge region with the rear mounting sleeve 6, the welding lap area and effective weld length between the longitudinal beam 3 and the rear mounting sleeve can be increased, reducing stress concentration at the load input point, thereby improving the connection reliability and durability of the rear mounting point area.

[0068] In some implementations, such as Figure 7 As shown, at the connection between the rear crossbeam 2 and the rear reinforcing tube 42, a cavity reinforcement 25 is provided inside the cavity. The cavity reinforcement 25 is connected to both the inner plate 21 and the outer plate 22 to establish a load transfer path within the rear crossbeam 2.

[0069] In order to avoid the rear reinforcing tube 42 concentrating the load on a single side plate, causing local buckling or weld fatigue, the cavity reinforcing member 25 distributes the load input by the rear reinforcing tube 42 to the inner plate 21 and the outer plate 22 simultaneously, so that the rear crossbeam 2 forms a composite load-bearing mode of "external welded connection + internal force transmission in the cavity", thereby improving the deformation resistance and fatigue resistance of the connection area of ​​the rear crossbeam 2.

[0070] Therefore, the cavity reinforcement 25 can improve the load-bearing reliability of the connection area between the rear crossbeam 2 and the rear reinforcing tube 42, reduce local stress concentration, and further improve the NVH of the whole vehicle.

[0071] To meet the installation and stress requirements of components such as the rear suspension spring arms, Figure 8 As shown, the rear crossbeam 2 is provided with two spring arm mounting seats 7, which are spaced apart along the length of the rear crossbeam 2.

[0072] As a typical load input hard point, the spring arm mounting base 7 bears loads with multi-directional coupling characteristics. To improve the local stiffness of this area and reduce the fatigue risk of the weld points, this embodiment further arranges support members 8 around the two spring arm mounting bases 7, so that the spring arm load can be distributed and transferred between the rear crossbeam 2 and the longitudinal beam 3.

[0073] Furthermore, such as Figure 9 As shown, the support member 8 includes a transverse support tube 81 and a longitudinal support tube 82. The transverse support tube 81 is connected between two spring arm mounting seats 7 to establish a rigid connection between the two mounting seats; one end of the longitudinal support tube 82 is connected to the transverse support tube 81, and the other end is connected to the longitudinal beam 3 to guide the spring arm load to the main load-bearing path of the longitudinal beam 3.

[0074] Therefore, the transverse support pipe 81, the longitudinal support pipe 82, the corresponding sections of the longitudinal beam 3, and the structure of the rear crossbeam 2 in the spring arm mounting base 7 area together constitute at least one closed load transfer loop. This closed loop allows the spring arm load to be distributed through multiple paths, reducing the concentrated stress on a single plate or a single weld point, thereby improving the strength, stiffness, and durability of the spring arm mounting base 7 area.

[0075] like Figure 10 As shown, the transverse support pipe 81 and the longitudinal support pipe 82 form a protective support structure for the area of ​​the spring arm mounting seat 7 in space. To ensure welding accessibility and assembly interference control, the ends of the transverse support pipe 81 and the longitudinal support pipe 82 may be provided with cut edges, fish mouths, or partial contact surfaces, so that they can be stably fitted with the longitudinal beam 3 and the structure near the spring arm mounting seat 7.

[0076] By optimizing the lateral arrangement, the support member 8 can participate more effectively in co-loading under load, improve the actual bearing efficiency of the closed load transfer loop, and further reduce the structural vibration response.

[0077] In some implementations, such as Figure 11 As shown, a connecting reinforcement 83 is provided between the rear crossbeam 2 and the transverse support tube 81. The connecting reinforcement 83 is located between the two spring arm mounting seats 7 and is used to establish a more direct load transfer connection between the rear crossbeam 2 and the transverse support tube 81.

[0078] By setting the connecting reinforcement 83, the transverse support tube 81 and the rear crossbeam 2 can form a stronger coupling relationship under torsional conditions, avoiding the relative deformation of the middle part caused by the transverse support tube 81 only participating in the force through the end connection, thereby improving the local stiffness and overall torsional performance of the spring arm mounting seat 7 area.

[0079] like Figure 12 As shown, the connecting reinforcement 83, together with the rear crossbeam 2 and the transverse support tube 81, forms a local reinforcement unit, dividing the original closed load transfer loop into at least two local closed loops. This loop separation method shortens the effective force transmission span of the local loop, making load transfer more direct; it also increases the torsional stiffness of the local loop, allowing the load input from the spring arm to be more evenly distributed to the rear crossbeam 2 and the longitudinal beam 3.

[0080] Therefore, the connecting reinforcement 83 not only improves the local stiffness and durability of the spring arm mounting area 7, but also improves the torsional mode level of the rear subframe assembly, further improving NVH.

[0081] In some embodiments, to improve the connection strength between the longitudinal support pipe 82 and the longitudinal beam 3 and reduce the fatigue risk at the connection, such as Figure 12 As shown, the longitudinal support pipe 82 has an enlarged hole or enlarged diameter structure at the end connected to the longitudinal beam 3 to increase the connection area.

[0082] Specifically, the enlarged hole structure can be understood as the opening diameter of the end of the longitudinal support pipe 82 being increased relative to the pipe body, so that when it is welded to the longitudinal beam 3, a larger overlap perimeter and effective weld length are formed; the diameter expansion structure can be understood as the end of the longitudinal support pipe 82 forming an end section with an increased outer diameter (for example, by end expansion forming, flange flaring or adding and welding a sleeve to form an enlarged end), thereby increasing the contact area and connection area between the end and the longitudinal beam.

[0083] Therefore, by setting an enlarged hole or enlarged diameter structure at the connection end of the longitudinal support pipe 82, the overlap area and weld bearing capacity at the connection between the longitudinal support pipe 82 and the longitudinal beam 3 can be significantly increased, making the load transmission of the closed load transmission loop more stable under the spring arm load input condition, reducing the unit stress level at the connection and the risk of weld fatigue cracking, thereby improving the durability and reliability of this area and improving the vibration transmission characteristics.

[0084] Finally, as Figure 13 As shown, the rear subframe assembly is based on a square frame providing a closed framework at the overall level. At key nodes, the front reinforcing tube 41 and the rear reinforcing tube 42 form a triangular closed-loop load-bearing structure. In the cavity of the rear crossbeam 2, the load transfer path between the inner plate 21 and the outer plate 22 is established through the cavity reinforcement 25. In the area of ​​the spring arm mounting seat 7, the closed load transfer loop is constructed and divided through the transverse support tube 81, the longitudinal support tube 82 and the connecting reinforcement 83.

[0085] Furthermore, such as Figure 13 As shown, within the area covered by the closed load transfer loop, a first mounting bracket 91, a second mounting bracket 92, a third mounting bracket 93, a fourth mounting bracket 94, and a fifth mounting bracket 95 are also provided. All of these mounting brackets are fixedly installed near the force path of the closed load transfer loop or within its envelope, enabling them to participate in load diversion and local stiffness reinforcement while providing a functional mounting interface, thus preventing the mounting interface from becoming a weak point.

[0086] Therefore, this embodiment can improve the overall torsional stiffness and local stiffness of the key load input area without significantly increasing weight and process complexity; reduce stress concentration and fatigue risk in the mounting point, node and spring arm mounting seat 7 area; and suppress the transmission of vibration and noise to the vehicle body, thereby improving the overall vehicle NVH and enhancing durability and reliability.

[0087] It should be noted that, in alternative implementations, the number, arrangement position, and cross-sectional shape of the front reinforcing tube 41 and the rear reinforcing tube 42 can be adjusted according to the vehicle platform, suspension type, and space arrangement requirements; the structural form of the mounting sleeve can also be replaced by a bushing seat, sleeve, or mounting hole seat; the structure of the supporting member 8 and the connecting reinforcing member 83 can also be equivalently deformed without changing the core force logic of the "closed load transmission loop".

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rear subframe assembly for a vehicle, characterized in that, include: The frame includes a front crossbeam, a rear crossbeam, and two longitudinal beams. The two longitudinal beams are spaced apart and connected to the front crossbeam and the rear crossbeam respectively to form a closed frame structure. A node reinforcement structure is provided at at least one connection node between the longitudinal beam and the front crossbeam and / or the rear crossbeam, which is used to connect the corresponding longitudinal beam with the front crossbeam and / or the rear crossbeam to form a closed-loop force-bearing structure with triangular support at the connection node.

2. The rear subframe assembly of a vehicle according to claim 1, characterized in that, The first end of the longitudinal beam is connected to the side wall of the front crossbeam, and the two ends of the rear crossbeam are respectively connected to the side walls of the two longitudinal beams. The two ends of the front crossbeam protrude from the longitudinal beam to form two front mounting point areas, and the second ends of the two longitudinal beams protrude from the rear crossbeam to form two rear mounting point areas. The front mounting point areas are provided with front mounting sleeves for connecting to the vehicle body, and the rear mounting point areas are provided with rear mounting sleeves for connecting to the vehicle body.

3. The rear subframe assembly of a vehicle according to claim 2, characterized in that, The node reinforcement structure includes a front reinforcement tube and a rear reinforcement tube, both of which are located on the outside of the frame. The front reinforcement tube is used to connect the front crossbeam and the longitudinal beam, and the rear reinforcement tube is used to connect the rear crossbeam and the longitudinal beam.

4. The rear subframe assembly of a vehicle according to claim 3, characterized in that, The diameter of the front crossbeam is smaller than the diameter of the front mounting sleeve, the diameter of the longitudinal beam is larger than the diameter of the rear mounting sleeve, and the diameters of the front mounting sleeve and the rear mounting sleeve are the same. And / or, a mounting point reinforcement is provided between the front mounting sleeve and the front crossbeam, the mounting point reinforcement is connected to the front crossbeam, one end of the front reinforcing tube is connected to the corresponding longitudinal beam, and the other end is connected to the mounting point reinforcement, the end of the front crossbeam is provided with a first conformal cut edge area, and the mounting point reinforcement cooperates with the first conformal cut edge area to form a partially enclosing support structure around the front mounting sleeve; The second end of the longitudinal beam is provided with a second conformal tangent area to form a partial surrounding support structure around the periphery of the rear-mounted sleeve.

5. The rear subframe assembly of a vehicle according to claim 4, characterized in that, Both ends of the front crossbeam and the second end of the longitudinal beam are provided with shaping sections. The first conformal cutting edge area is provided on the shaping section corresponding to the front crossbeam, and the second conformal cutting edge area is provided on the shaping section corresponding to the longitudinal beam. The cross section of the shaping section transitions from a circle to a square or approximately square. The cross section of the rear reinforcing tube is square or approximately square, and the cross section of the front reinforcing tube is circular or approximately circular.

6. The rear subframe assembly of a vehicle according to claim 3, characterized in that, The rear crossbeam includes an inner plate and an outer plate that are connected to each other. A cavity is formed between the inner plate and the outer plate. At the connection between the rear crossbeam and the rear reinforcing tube, a cavity reinforcing member is provided in the cavity. The cavity reinforcing member is connected to both the inner plate and the outer plate.

7. A rear subframe assembly for a vehicle according to any one of claims 1-6, characterized in that, The rear crossbeam is provided with two spring arm mounting seats, which are spaced apart along the length of the rear crossbeam; and the rear subframe assembly is provided with a support member around the two spring arm mounting seats, which cooperates with the rear crossbeam and the longitudinal beam to form a closed load transfer loop in the area of ​​the spring arm mounting seats.

8. The rear subframe assembly of a vehicle according to claim 7, characterized in that, The supporting components include transverse supporting pipes and longitudinal supporting pipes; The transverse support tube is connected between the two spring arm mounting seats; One end of the longitudinal support pipe is connected to the transverse support pipe, and the other end is connected to the longitudinal beam; The transverse support pipe, the longitudinal support pipe, the corresponding section of the longitudinal beam, and the structure of the rear crossbeam in the spring arm mounting area together constitute at least one closed load transfer loop.

9. A rear subframe assembly for a vehicle according to claim 8, characterized in that, A connecting reinforcement is provided between the rear crossbeam and the transverse support tube, and the connecting reinforcement is located between the two spring arm mounting seats.

10. A rear subframe assembly for a vehicle according to claim 8, characterized in that, The longitudinal support pipe has an enlarged hole or enlarged diameter structure at the end that connects to the longitudinal beam to increase the connection area.

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