A design method of a double fork arm pressure casting aluminum alloy shock tower structure

Abstract

The present application belongs to the technical field of vehicle engine cabin damping tower structure, and particularly relates to a design method of a double-fork-arm die-cast aluminum alloy damping tower structure, comprising the following steps: S1: extracting the constraint boundary of the damping tower casting according to the whole vehicle modeling function; S2: determining the parting scheme of the whole damping tower casting, and dividing the casting dynamic mold forming area, the casting fixed mold forming area and the casting core-pulling forming area; S3: adding an accessory structure on the main body structure of the damping tower casting; and S4: adding a mounting point structure on the main body structure of the damping tower casting. The purpose is to solve the problem that the existing design of the double-fork-arm die-cast aluminum alloy damping tower structure needs to use five-axis and above equipment or four-axis equipment to match two sets of clamps and multiple clamping during processing, thereby causing high construction cost of the damping tower processing production line, high cost of the clamp, more single-piece processing procedures, long processing rhythm, and increased size precision control risk caused by multiple clamping.

Description

Technical Field

[0001] This invention belongs to the technical field of vehicle engine compartment shock absorber tower structure, specifically relating to a design method for a die-cast aluminum alloy shock absorber tower structure with double fork arms. Background Technology

[0002] With the booming development of new energy vehicles and driven by policies such as carbon emission reduction, the technologies of vehicle lightweighting and integrated body component structure are constantly being innovated.

[0003] The shock absorber tower is a crucial automotive component, a key part connecting the shock absorber and the front of the vehicle body. During driving, impact loads caused by uneven road surfaces are attenuated by the shock absorber and transferred to the tower, subsequently dispersing to the front of the vehicle. The shock absorber tower plays a vital role in improving vehicle stability and overall NVH (noise, vibration, and harshness) performance. Currently, shock absorber towers primarily utilize a multi-piece stamping and welding process, resulting in complex manufacturing procedures, high production costs, and low installation and disassembly efficiency. Furthermore, temperature differences near the weld points during welding can easily cause localized stress concentration, affecting the overall assembly accuracy. While die-cast aluminum alloy shock absorber towers have matured as a representative product of lightweight and integrated vehicle body design, developing aluminum alloy structural components suitable for die-casting processes relies heavily on experience and repeated testing, leading to low design efficiency and unsatisfactory lightweighting results.

[0004] Chinese Patent CN108038308A discloses a structural design method for aluminum alloy vibration damping towers. The method involves extracting relevant performance data and establishing a topology optimization space based on structural analysis and experimental testing results of the original steel vibration damping tower. The topology optimization space is then divided into design and non-design areas. For the design area, topology optimization is used to determine the optimal distribution of reinforcing ribs. Based on the reinforcing rib distribution obtained from the topology optimization, a new vibration damping tower model with reinforcing ribs is established, and the optimal thickness of the reinforcing ribs is further obtained through size optimization. Finally, the size-optimized vibration damping tower model is checked to ensure that the designed structure meets the performance requirements. This invention shortens the design cycle, improves design efficiency, significantly reduces structural weight, and substantially enhances overall performance.

[0005] However, currently, die-cast aluminum alloy shock absorber tower structures with double wishbone configurations exhibit a common phenomenon: 1. The mounting surface of the double wishbone is at a spatial angle relative to the vehicle's XYZ coordinates; 2. Most of the corresponding sensors, wiring harness holes, etc., on the shock absorber tower are also at spatial angles. These two phenomena necessitate the use of five-axis or higher equipment, or four-axis equipment with two or more sets of fixtures and multiple clamping operations, for machining the shock absorber tower. This results in higher construction costs for the shock absorber tower machining production line, higher fixture costs, more machining steps per piece, and longer machining cycles. Furthermore, multiple clamping operations increase the risk of dimensional accuracy control issues. Summary of the Invention

[0006] The purpose of this invention is to provide a design method for a die-cast aluminum alloy vibration damping tower structure with double fork arms, which addresses the problem mentioned in the background art that the existing double fork arm die-cast aluminum alloy vibration damping tower structure requires the use of five-axis or higher equipment or four-axis equipment to match two or more sets of fixtures and multiple clamping operations during processing. This results in high construction costs for the vibration damping tower processing production line, high fixture costs, numerous processing steps per piece, and long processing cycles. In addition, multiple clamping operations also increase the risk of dimensional accuracy control issues.

[0007] To achieve the above-mentioned technical objectives, the technical solution adopted by the present invention is as follows:

[0008] A structural design method for a die-cast aluminum alloy vibration damping tower with double fork arms includes the following steps:

[0009] S1: Extract the constraint boundaries of the shock absorber tower casting based on the overall vehicle styling function, and determine the installation points and clearance control of each component.

[0010] S2: Determine the overall parting scheme for the shock absorber tower casting, and divide the casting into the moving mold forming area, the casting fixed mold forming area, and the casting core pulling forming area;

[0011] S3: Add auxiliary structures to the main structure of the shock absorber tower casting;

[0012] S4: Addition of installation point structure to the main structure of the shock absorber tower casting.

[0013] Based on the above solution, the present invention has made the following improvements:

[0014] Furthermore, in step S2, when determining the overall parting scheme of the shock absorber tower casting, the input double fork arm structural features are used as the main basis for designing the mold exit direction of the shock absorber tower casting. Then, an initial reference plane is formed, and a core-pulling parting plane is obtained based on the initial reference plane. The shock absorber spring axis is used as the initial reference direction for the main parting. A direction between the initial reference direction for the main parting and the core-pulling parting plane is selected as the main parting direction for the shock absorber tower casting. Based on the main parting direction for the shock absorber tower casting, the moving mold forming area, the fixed mold forming area, and the core-pulling forming area can be divided.

[0015] Furthermore, during the formation of the initial reference plane, the mounting points on both sides of the input double-wishbone structure feature are connected, so that the two mounting points form a straight line, which is the rotation axis of the double-wishbone. The initial reference plane is formed by stretching along this straight line in the Z direction.

[0016] Furthermore, during the formation process, the initial reference plane is rotated along the rotation axis of the double fork arm to form the core-pulling parting plane, and the normal direction of the core-pulling parting plane near the inner side of the cabin is the core-pulling direction.

[0017] Furthermore, the initial reference plane rotates at an angle greater than 1.5° along the rotation axis of the double fork arm, and the rotated initial reference plane intersects with the longitudinal beam.

[0018] Furthermore, during the selection of the main parting direction of the shock absorber tower casting, the main parting direction of the shock absorber tower casting is perpendicular to the core-pulling direction.

[0019] Furthermore, in step S2, when dividing the casting moving mold forming area, the casting fixed mold forming area, and the casting core pulling forming area, the upper part of the shock absorber tower casting in the main parting direction is the casting fixed mold forming direction, the lower structural area of ​​the shock absorber tower casting in the main parting direction is the casting moving mold forming direction, and the local structure of the shock absorber tower casting in the core pulling direction is the core pulling forming area.

[0020] Furthermore, in step S3, when adding auxiliary structures to the main structure of the shock absorber tower casting, the following structures are added in sequence: shock absorber spring mounting structure, double fork arm mounting structure, clearance notch for double fork arm movement, shotgun lap joint structure, and longitudinal beam lap joint structure.

[0021] Furthermore, in step S1, the mounting point structure includes, but is not limited to, wire harness mounting points, sensor mounting points, and electrical mounting points. When adding the mounting point structure, the principle should be that the direction of the machining holes and the normal of the machining surface of all mounting surfaces must be perpendicular to the rotation axis of the double fork arm or the core-pulling direction.

[0022] Furthermore, in step S1, when the main structure of the shock absorber tower casting does not meet the principle of adding installation point structures, a local protrusion structure is added, and then the plane of the local protrusion structure is modified to be perpendicular to the rotation axis of the double fork arm or the core pulling direction.

[0023] The invention employing the above technical solution has the following advantages:

[0024] 1. By changing the parting design of the die-cast structure of the shock absorber tower and the structural design of the installation point, the problems of high processing cost, low efficiency and high processing accuracy risk caused by the double fork arm mounting surface and the installation point structure can be avoided.

[0025] 2. Through the shock absorber tower structure design method in this scheme, the entire shock absorber tower can be processed in a maximum of two steps using only a four-axis machining equipment and a set of fixtures during the shock absorber tower die casting process, thereby improving processing efficiency and reducing processing costs. Attached Figure Description

[0026] The present invention can be further illustrated by the non-limiting embodiments given in the accompanying drawings;

[0027] Figure 1 This is a schematic diagram illustrating the definition of the damping tower boundary and parting direction in the structural design method of a die-cast aluminum alloy damping tower with double forks in this invention;

[0028] Figure 2 This is a schematic diagram of the main structure of a shock absorber tower in the design method of a die-cast aluminum alloy shock absorber tower with double fork arms according to the present invention.

[0029] Figure 3 This is a schematic diagram of the installation point structure on the shock absorber tower in the design method of a die-cast aluminum alloy shock absorber tower with double fork arms according to the present invention.

[0030] The symbols for the main components are explained below:

[0031] (31) Vehicle coordinate system 1. Double wishbone structure 2. Double wishbone rotation axis 3. Suspension structure 4. Suspension structure axis 5. Initial reference plane 6. Shock absorber core pulling direction 7. Casting moving mold forming direction 8. Casting fixed mold forming direction 9. Fixed mold forming area 10. Moving mold forming area 11. Local core pulling area 12. Example A 13. Example B 14. Mounting surface normal and mounting hole axis direction of Example A 15. Mounting surface normal and mounting hole axis direction of Example B 16. Detailed Implementation

[0032] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that similar or identical parts are referred to by the same reference numerals in the drawings or description. Implementations not shown or described in the drawings are forms known to those skilled in the art. In addition, directional terms mentioned in the embodiments, such as "up," "down," "top," "bottom," "left," "right," "front," and "back," are only for reference to the directions in the drawings and are not intended to limit the scope of protection of the present invention.

[0033] like Figures 1-3 As shown, the present invention provides a structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms, comprising the following steps:

[0034] S1: In CATIA software, based on the functional model input of the whole vehicle, the constraint boundary conditions of the shock absorber tower casting are sorted out. Based on the whole vehicle coordinate system 1, the double wishbone structure 2 and suspension structure 4 are extracted and made, and the installation points of each pair of components and the clearance control are determined.

[0035] S2: Connect the two mounting points of the input double wishbone structure diagram to form a straight line. This straight line is the double wishbone rotation axis 3. Draw the suspension structure axis 5 according to the suspension structure 4. Stretch along the Z-axis of the vehicle coordinate system according to the double wishbone rotation axis 3 to obtain the initial reference plane 6.

[0036] The initial reference plane 6 is rotated along the double wishbone rotation axis 3 by a certain angle, which is generally greater than 1.5°. The initial reference plane 6 must be rotated so that it intersects with the longitudinal beam to obtain the core-pulling plane. The normal direction of the core-pulling plane closest to the inner side of the engine compartment is the core-pulling direction 7 of the shock absorber tower. In some embodiments, the specific value of this rotation angle depends on the overlap method and width between the bottom of the shock absorber tower and the vehicle body longitudinal beam. The intersection line between the core-pulling plane and the longitudinal beam can be drawn, and the distance between the intersection line in the Y direction and the edge of the longitudinal beam is the usable overlap width.

[0037] Using the shock absorber spring axis as the initial reference direction for the main parting line, a plane perpendicular to the core-pulling plane is drawn through the suspension axis 5. On this plane, a straight line within the angle formed by the suspension axis 5 and the core-pulling plane is selected as the main parting line direction for the shock absorber tower casting. The following conditions must be met when selecting this straight line: a) The straight line must be within the angle; b) The overlap method and width between the bottom of the shock absorber tower and the longitudinal beam of the vehicle body must be considered; c) Reinforcing structures such as reinforcing ribs or reinforcing cavities in the Z-direction of the shock absorber tower must be considered to minimize the increase in metal material due to demolding; d) The main cavity of the shock absorber tower stretched out must meet the clearance requirements with the suspension spring. The main parting line direction of the shock absorber tower casting should be kept as perpendicular as possible to the core-pulling direction 7 to reduce the failure rate of the die-cast shock absorber tower production mold.

[0038] Based on the main parting direction of the shock absorber tower casting, the upper part of the shock absorber tower casting in the main parting direction is the fixed mold forming direction 9, the lower structural area of ​​the shock absorber tower casting in the main parting direction is the moving mold forming direction 8, and the local structure of the core pulling direction 7 of the shock absorber tower casting is the core pulling forming area.

[0039] S3: A damping spring mounting structure, a double-wishbone mounting structure, a clearance notch for the double-wishbone movement, a shotgun lap joint structure, and a longitudinal beam lap joint structure are sequentially added to the main body of the damping tower casting. In some embodiments, the damping spring mounting structure is designed in the middle of the main parting direction of the damping tower casting, the double-wishbone mounting structure is designed in the upper part of the main parting direction of the damping tower casting, the clearance notch for the double-wishbone movement is designed on the rear side of the double-wishbone mounting structure, the shotgun lap joint structure is designed on the edge of the main parting direction of the damping tower casting, and the longitudinal beam lap joint structure is designed on the shotgun lap joint structure in the main parting direction of the damping tower casting, thereby forming the damping tower casting structure, such as... Figure 2 As shown, the main structure of the shock absorber tower casting has a moving mold forming area 11, a fixed mold forming area 10, and a partial core-pulling area 12.

[0040] S4: Mounting point structures are added to the main structure of the shock absorber tower casting. In some embodiments, these mounting point structures mainly include wiring harness mounting points, sensor mounting points, and electrical mounting points. When designing these mounting point structures, the following principles should be met: the direction of the machined holes and the normal direction of the machined surfaces must be perpendicular to the rotation axis of the double fork arm or the aforementioned core-pulling direction. When the main structure of the shock absorber tower casting does not meet the principles for adding mounting point structures, a local protrusion structure is added, and the plane of the local protrusion structure is then corrected to be perpendicular to the rotation axis of the double fork arm or the aforementioned core-pulling direction.

[0041] In some embodiments, such as Figure 3 As shown, the structural forms of mounting point structure design example A13 and mounting point structure design example B14 use a partial protrusion structure. The mounting surface normal and mounting hole axis direction 15 of example A13 are modified to be perpendicular to the double fork arm rotation axis 3; the mounting surface normal and mounting hole axis direction 16 of example B14 are modified to be perpendicular to the core pulling direction 7.

[0042] The aluminum alloy shock absorber tower with double forks designed by the above method can be processed on all surfaces using only a four-axis machining equipment and a set of fixtures during die casting. The workpiece only needs to rotate along the rotation axis 3 of the double forks or the core pulling direction 7 to complete all processing. Compared with the existing shock absorber tower die casting design, it can effectively reduce processing costs, improve processing efficiency, and improve processing accuracy.

[0043] The above provides a detailed description of the structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms provided by this invention. The specific embodiments are described only to aid in understanding the method and core ideas of this invention. It should be noted that those skilled in the art can make various improvements and modifications to this invention without departing from its principles, and these improvements and modifications also fall within the scope of protection of the claims of this invention.

Claims

1. A structural design method for a die-cast aluminum alloy vibration damping tower with double fork arms, characterized in that: Includes the following steps: S1: Extract the constraint boundaries of the shock absorber tower casting based on the overall vehicle styling function, and determine the installation points and clearance control of each component. S2: Determine the overall parting scheme for the shock absorber tower casting, and divide the casting into the moving mold forming area, the casting fixed mold forming area, and the casting core pulling forming area; S3: Add auxiliary structures to the main structure of the shock absorber tower casting; S4: Addition of installation point structure to the main structure of the shock absorber tower casting; In step S2, when determining the overall parting scheme of the shock absorber tower casting, the input double fork arm structural features are used as the main basis for designing the mold exit direction of the shock absorber tower casting. Then, an initial reference plane is formed, and a core-pulling parting plane is obtained based on the initial reference plane. The shock absorber spring axis is used as the initial reference direction of the main parting. A direction between the initial reference direction of the main parting and the core-pulling parting plane is selected as the main parting direction of the shock absorber tower casting. Based on the main parting direction of the shock absorber tower casting, the moving mold forming area, the fixed mold forming area, and the core-pulling forming area of ​​the casting can be divided.

2. The structural design method for a die-cast aluminum alloy vibration damping tower with double fork arms according to claim 1, characterized in that: During the formation of the initial reference plane, the mounting points on both sides of the input double-wishbone structure feature are connected so that the two mounting points form a straight line, which is the rotation axis of the double-wishbone. The initial reference plane is formed by stretching along this straight line in the Z direction.

3. The structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms according to claim 2, characterized in that: During the formation process, the initial reference plane is rotated along the rotation axis of the double fork arm to form the core-pulling parting plane. The normal direction of the core-pulling parting plane near the inner side of the cabin is the core-pulling direction.

4. The structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms according to claim 3, characterized in that: The initial reference plane rotates at an angle greater than 1.5° along the rotation axis of the double fork arm, and the rotated initial reference plane intersects with the longitudinal beam.

5. The structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms according to claim 3, characterized in that: During the selection of the main parting direction of the shock absorber tower casting, the main parting direction of the shock absorber tower casting is perpendicular to the core pulling direction.

6. The structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms according to claim 3, characterized in that: In step S2, when dividing the casting moving mold forming area, the casting fixed mold forming area, and the casting core pulling forming area, the upper part of the shock absorber tower casting in the main parting direction is the casting fixed mold forming direction, the lower structural area of ​​the shock absorber tower casting in the main parting direction is the casting moving mold forming direction, and the local structure of the shock absorber tower casting in the core pulling direction is the core pulling forming area.

7. The structural design method for a die-cast aluminum alloy vibration damping tower with double fork arms according to claim 1, characterized in that: In step S3, when adding auxiliary structures to the main structure of the shock absorber tower casting, the following structures are added in sequence: shock absorber spring mounting structure, double fork arm mounting structure, clearance notch for double fork arm movement, shotgun lap joint structure, and longitudinal beam lap joint structure.

8. A structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms according to any one of claims 2 or 3, characterized in that: In step S4, the mounting point structure includes, but is not limited to, wire harness mounting points, sensor mounting points, and electrical mounting points. When adding mounting point structures, the principle should be that the direction of the machining holes and the normal of the machining surface of all mounting surfaces must be perpendicular to the rotation axis of the double fork arm or the core-pulling direction.

9. The structural design method for a die-cast aluminum alloy shock absorber tower with double fork arms according to claim 8, characterized in that: In step S4, when the main structure of the shock absorber tower casting does not meet the principle of adding installation point structures, a local protrusion structure is added, and then the plane of the local protrusion structure is modified to be perpendicular to the rotation axis of the double fork arm or the core pulling direction.

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