Magnesium alloy die-casting steering wheel framework

Abstract

The invention relates to the technical field of steering wheels, in particular to a magnesium alloy die-casting steering wheel framework which comprises a rim and a hub, the hub comprises a hub body and a connecting cylinder, the hub body is connected with the rim through a plurality of spokes, and the lower portion of the connecting cylinder is connected with a steering column; the device further comprises an energy absorption structure and an energy absorption piece. The energy absorption structure comprises a guide groove and guide blocks, the guide groove is formed in the circumferential direction of the outer wall of the connecting cylinder, and the multiple guide blocks are arranged in the guide groove in an annular array mode; the inner wall of the connecting cylinder is connected with a limiting ring corresponding to the guide groove, the energy absorption piece comprises an energy absorption cylinder located in the connecting cylinder and aluminum foam, the upper end of the energy absorption cylinder is open, the open end is connected with the bottom of the hub body, and the aluminum foam is arranged in the energy absorption cylinder. The problem that when an existing die-casting magnesium alloy steering wheel framework is used, a hub area on the steering wheel framework is prone to brittle fracture when an automobile collides is solved.

Description

Technical Field

[0001] This invention relates to the field of steering wheel technology, specifically to a magnesium alloy die-cast steering wheel frame. Background Technology

[0002] The steering wheel is a core component in a car used to control the vehicle's direction of travel. It transmits the driver's steering inputs to the wheels through the steering system. Current car steering wheels typically consist of a metal frame covered with a soft material, and integrate multi-function buttons for audio and cruise control, as well as paddle shifters and a heating module. The steering wheel frame is the "skeleton" of the entire steering wheel system, including the rim, spokes, and hub. Magnesium alloys, due to their low density and high strength, are widely used in lightweight design for automotive steering wheel frames.

[0003] However, magnesium alloys have inherent defects such as poor plasticity and brittle fracture during collisions. Furthermore, the steering wheel frame is prone to irregular brittle fracture during collisions, which can easily injure the driver. Moreover, relying solely on the deformation of the magnesium alloy frame for collision energy absorption is inefficient. In addition, the wheel hub, which connects to the steering column on the steering wheel frame, is integrally die-cast with the frame. During a collision, the impact force on the steering column is first transmitted to the wheel hub. Since the wheel hub is also die-cast from magnesium alloy and part of the steering wheel frame, it lacks energy-absorbing structures and is prone to brittle fracture after impact, thus easily causing injury to the driver. The article "Analysis of the Causes of Steering Wheel Frame Fracture" also emphasizes that stress concentration and structural defects in the wheel hub area make it more susceptible to fracture, making it one of the most vulnerable parts of the steering wheel. Summary of the Invention

[0004] To address the problem that existing die-cast magnesium alloy steering wheel frames are prone to brittle fracture in the hub area during vehicle collisions, this invention provides a magnesium alloy die-cast steering wheel frame with an energy-absorbing structure in the hub area to reduce the risk of brittle fracture.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A magnesium alloy die-cast steering wheel frame includes a rim and a hub. The hub includes a hub body and a connecting cylinder connected to the bottom of the hub body. The hub body is connected to the rim via multiple spokes. The lower part of the connecting cylinder is connected to the steering column. The frame also includes an energy-absorbing structure and an energy-absorbing component disposed on the connecting cylinder.

[0007] The energy-absorbing structure includes a guide groove and guide blocks. The guide groove is opened circumferentially along the outer wall of the connecting cylinder. Multiple guide blocks are arranged in a ring array inside the guide groove. Each guide block is a block with a right-angled triangular cross-section. The upper side and inner side of the guide block are fixed to the upper side wall and inner bottom wall of the guide groove, respectively. The inclined surface of the guide block gradually approaches the inner bottom wall of the guide groove from top to bottom. The guide blocks and the guide groove together form a groove.

[0008] The inner wall of the connecting cylinder is connected to a limiting ring corresponding to the guide groove. The energy-absorbing component includes an energy-absorbing cylinder and aluminum foam located inside the connecting cylinder. The upper end of the energy-absorbing cylinder is open and the open end is connected to the bottom of the wheel hub body. The closed end passes through the limiting ring and has a gap with the steering column. The aluminum foam is located inside the energy-absorbing cylinder.

[0009] Furthermore, the inner wall of the connecting cylinder on the lower side of the energy-absorbing cylinder is provided with multiple spline grooves, and the peripheral wall of the steering column is provided with connecting splines that correspond one-to-one with the spline grooves.

[0010] Furthermore, the depth of the guide groove is 60%-70% of the thickness of the connecting cylinder wall. Reinforcing rings are fixedly fitted on the outer walls of the connecting cylinder on the upper and lower sides of the guide groove. The longitudinal section of the reinforcing rings is a vertical isosceles trapezoid shape with a smaller outer section and a larger inner section. The two reinforcing rings are symmetrical about the middle of the guide groove.

[0011] Furthermore, the guide groove contains eight guide blocks, each guide block having an inner side surface that corresponds to the bottom wall of the guide groove, and the inner side surface of each guide block intersects with the inner side surface of the adjacent guide block. The inner sides surface of the eight guide blocks intersect end to end to form a circle; the angle between the inclined surface and the top surface of each guide block is 45 degrees.

[0012] Furthermore, the multiple guide blocks and connecting cylinders are integrally die-cast, with the outer end of the top surface of each guide block transitioning to the outer wall of the connecting cylinder via an arc; and the outer end of the lower side surface of each guide groove transitioning to the outer wall of the connecting cylinder via an arc.

[0013] Furthermore, the top surface of the limiting ring is flush with the upper side wall of the guide groove, the bottom surface is flush with the lower side wall of the guide groove, the outer end of the top surface of the limiting ring is arc-shaped transitioned with the inner wall of the connecting cylinder, and the outer end of the bottom surface of the limiting ring is arc-shaped transitioned with the inner wall of the connecting cylinder.

[0014] Furthermore, the energy-absorbing cylinder is a cylindrical body made of aluminum, and the outer diameter of the energy-absorbing cylinder matches the inner diameter of the limiting ring. Multiple annular grooves are recessed from top to bottom on the outer wall of the energy-absorbing cylinder.

[0015] Furthermore, the aluminum foam includes aluminum foam layer one, aluminum foam layer two, and aluminum foam layer three arranged from top to bottom inside the energy-absorbing cylinder. The porosity of aluminum foam layer one is 60%-65%, the porosity of aluminum foam layer two is 66%-74%, and the porosity of aluminum foam layer three is 75%-80%.

[0016] Furthermore, triangular anti-slip protrusions are distributed on both the bottom surface of the limiting ring and the top surface of the steering column.

[0017] Furthermore, the surface roughness Ra of the inclined surface of each guide block is 3.2 μm-6.3 μm.

[0018] The beneficial effects of the present invention through the above technical solution are as follows:

[0019] This invention addresses the poor plasticity and brittle fracture characteristics of magnesium alloys by introducing a guide groove and guide block structure into the energy-absorbing structure. By converting axial impact force into shear force, the material undergoes ordered sliding plastic deformation instead of disordered brittle fracture, thus controllably dissipating most of the collision energy and solving the problem of the single and unreliable energy absorption method of magnesium alloys under impact load.

[0020] This invention achieves a multi-stage synergistic energy absorption mechanism involving the plastic deformation of the connecting cylinder, the compression of aluminum foam, and the limiting ring. First, the energy-absorbing structure dominates energy absorption; then, the efficient compression of layered aluminum foam assists in energy dissipation; and finally, the limiting ring with triangular anti-slip protrusions provides a hard stop. The entire process involves progressive and controllable energy absorption, ultimately reliably limiting steering wheel intrusion and significantly improving the safety of the passenger compartment. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a cross-sectional front view of the connecting cylinder and energy-absorbing component of the present invention;

[0023] Figure 3 yes Figure 2 A magnified view of a section at point A in the middle;

[0024] Figure 4 yes Figure 2 Sectional view at point BB;

[0025] Figure 5 This is a schematic diagram of the structure of the multiple guide blocks of the present invention;

[0026] Figure 6 This is a schematic diagram of the energy-absorbing cylinder of the present invention;

[0027] Figure 7 This is a schematic diagram of the limiting ring of the present invention;

[0028] Figure 8 This is a schematic diagram of the steering column of the present invention.

[0029] The attached diagram is labeled as follows: 1. Wheel flange, 2. Wheel hub body, 3. Connecting cylinder, 4. Wheel spoke, 5. Steering column, 6. Guide groove, 7. Guide block, 8. Limiting ring, 9. Energy-absorbing cylinder, 10. Aluminum foam, 10a. Aluminum foam layer one, 10b. Aluminum foam layer two, 10c. Aluminum foam layer three, 11. Spline groove, 12. Connecting spline, 13. Reinforcing ring rib, 14. Ring groove, 15. Triangular anti-slip protrusion, 16. Guide ring. Detailed Implementation

[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments:

[0031] like Figures 1 to 8 As shown, a magnesium alloy die-cast steering wheel frame includes a rim 1 and a hub. The hub includes a hub body 2 and a connecting cylinder 3 connected to the bottom of the hub body 2. The connecting cylinder 3 is a cylindrical body with open ends. The hub body 2 is connected to the rim 1 via multiple spokes 4. The lower part of the connecting cylinder 3 is connected to the steering column 5. The rim 1, spokes 4, hub body 2, and connecting cylinder 3 are integrally die-cast from magnesium alloy. The frame also includes an energy-absorbing structure and energy-absorbing components disposed on the connecting cylinder 3. The energy-absorbing structure includes a guide groove 6 and guide blocks 7. The guide groove 6 is circumferentially opened along the outer wall of the connecting cylinder 3 and is an annular groove with the opening facing outwards. Multiple guide blocks 7 are arranged in a circular array within the guide groove 6, and each guide block 7 is a block with a right-angled triangular cross-section. The upper and inner sides of the guide blocks 7 are respectively connected to... The upper side wall and inner bottom wall of the guide groove 6 are fixed. The inner bottom wall of the guide groove 6 is the side opposite to the opening of the guide groove 6. The inner side of the guide block 7 is the side facing the inner bottom wall of the guide groove 6. The side between the upper side and the inner side of the guide block 7 is an inclined surface facing the lower side of the guide groove 6. The inclined surface of the guide block 7 gradually approaches the inner bottom wall of the guide groove 6 from top to bottom. Two adjacent guide blocks 7 together with the guide groove 6 form a groove. The inner wall of the connecting cylinder 3 is connected to a limiting ring 8 corresponding to the guide groove 6. The limiting ring 8 is a circular ring integrally formed with the connecting cylinder 3. The energy-absorbing component includes an energy-absorbing cylinder 9 and an aluminum foam 10 located inside the connecting cylinder 3. The upper end of the energy-absorbing cylinder 9 is open and the open end is connected to the bottom of the hub body 2. The closed end passes through the limiting ring 8 and has a gap with the steering column 5. The aluminum foam 10 is located inside the energy-absorbing cylinder 9.

[0032] The inner wall of the connecting cylinder 3 on the lower side of the energy-absorbing cylinder 9 is provided with a plurality of spline grooves 11, and the peripheral wall of the steering column 5 is provided with connecting splines 12 that correspond one-to-one with the spline grooves 11.

[0033] The depth of the guide groove 6 is 60%-70% of the wall thickness of the connecting cylinder 3. Reinforcing ring ribs 13 are fixedly fitted on the outer walls of the connecting cylinder 3 on the upper and lower sides of the guide groove 6. The reinforcing ring ribs 13 are circular rings. The longitudinal section of the reinforcing ring ribs 13 is a vertical isosceles trapezoidal shape with a smaller outer section and a larger inner section. The "outer" in "smaller outer section and larger inner section" refers to the side away from the connecting cylinder 3, and the "inner" refers to the side connected to the connecting cylinder 3. The two reinforcing ring ribs 13 are symmetrical about the middle of the guide groove 6. The reinforcing ring ribs 13 have a reinforcing effect on the connecting cylinder 3, ensuring that the steering wheel still has sufficient structural rigidity and fatigue life in the weak area where the guide groove 6 is opened under loads such as daily steering and vibration.

[0034] The guide groove 6 contains 8 guide blocks 7. The inner side of each guide block 7 is an arc-shaped surface that matches the inner bottom wall of the guide groove 6. The inner side of each guide block 7 intersects with the inner side of the adjacent guide block 7. The inner sides of the 8 guide blocks 7 intersect end to end to form a circle. The angle between the inclined surface and the top surface of each guide block 7 is 45 degrees.

[0035] Multiple guide blocks 7 and connecting cylinder 3 are integrally die-cast, with the outer end of the top surface of each guide block 7 transitioning to the outer wall of the connecting cylinder 3 by an arc; the outer end of the lower side surface of each guide groove 6 transitioning to the outer wall of the connecting cylinder 3 by an arc; the purpose is to avoid stress concentration.

[0036] The top surface of the limiting ring 8 is flush with the upper side wall of the guide groove 6, and the bottom surface is flush with the lower side wall of the guide groove 6. The outer end of the top surface of the limiting ring 8 is arc-shaped and transitions to the inner wall of the connecting cylinder 3. The outer end of the bottom surface of the limiting ring 8 is arc-shaped and transitions to the inner wall of the connecting cylinder 3. The purpose is to avoid stress concentration.

[0037] The energy-absorbing cylinder 9 is a cylindrical body made of aluminum. The outer diameter of the energy-absorbing cylinder 9 corresponds to the inner diameter of the limiting ring 8. The outer wall of the energy-absorbing cylinder 9 is in contact with the inner wall of the limiting ring 8. Multiple annular grooves 14 are recessed from top to bottom on the outer wall of the energy-absorbing cylinder 9. The annular grooves 14 are circular grooves with their openings facing outwards. The purpose of setting the annular grooves 14 on the energy-absorbing cylinder 9 is to reduce the wall thickness and facilitate the compression of the energy-absorbing cylinder 9. Multiple guide rings 16 are provided at intervals on the inner wall of the connecting cylinder above the limiting ring. The inner ring of each guide ring 16 is fitted around the energy-absorbing cylinder 9. The outer diameter of the energy-absorbing cylinder 9 corresponds to the inner diameter of the guide ring 16. The guide ring 16 is a circular body made of magnesium alloy. The distance from the energy-absorbing cylinder 9 to the steering column 5 is the same as the distance between the upper and lower side walls of the guide groove 6.

[0038] The aluminum foam 10 includes aluminum foam layer 10a, aluminum foam layer 10b, and aluminum foam layer 10c arranged from top to bottom within the energy-absorbing cylinder 9. The porosity of aluminum foam layer 10a is 60%-65%, the porosity of aluminum foam layer 10b is 66%-74%, and the porosity of aluminum foam layer 10c is 75%-80%. For example, when the porosity of aluminum foam layer 10a is 60%, the porosity of aluminum foam layer 10b is 66%, and the porosity of aluminum foam layer 10c is 75%; when the porosity of aluminum foam layer 10a is 65%, the porosity of aluminum foam layer 10b is 74%, and the porosity of aluminum foam layer 10c is 80%.

[0039] The bottom surface of the limiting ring 8 and the top surface of the steering column 5 are evenly distributed with triangular anti-slip protrusions 15; the purpose is to prevent slippage when the limiting ring 8 and the steering column 5 are in contact.

[0040] The surface roughness Ra of the inclined surface of each guide block 7 is 3.2μm-6.3μm.

[0041] When a vehicle collision occurs, the impact load is transmitted upwards through the steering column 5 to the connecting cylinder 3 of the steering wheel frame. This load first acts on the guide groove 6 area. Since the depth of the guide groove 6 accounts for 60%–70% of the wall thickness of the connecting cylinder 3, and there are eight guide blocks 7 arranged in a ring inside, this area becomes the primary weak point for deformation of the entire connecting cylinder 3. Each guide block 7 is a block with a right-angled triangular cross-section, its inclined surface forming a 45° angle with its top surface, and the inclined surface faces the steering column 5 (i.e., the direction of the impact force). Under the action of the axial impact force, the impact force is decomposed into shear force along the inclined surface and compressive stress perpendicular to the inclined surface, driving the guide block 7 to undergo directional and orderly plastic sliding deformation along the inclined surface. This is because, for magnesium alloys… For materials with poor plasticity, pure pressure or tension can easily lead to brittle fracture, while shearing is a mode that more easily induces controllable plastic deformation. The guide block's inclined surface is designed with a 45° angle to generate the shear force that drives the connecting cylinder 3 to slide, thus guiding deformation in the form of "slippage" rather than "fracture." The roughening treatment on the inclined surface of the guide block 7 increases sliding friction, ensuring that the slippage is stable and gradual, rather than an instantaneous instability and slippage. Moreover, by symmetrically setting reinforcing ribs 13 on the upper and lower sides of the guide groove 6, a clear deformation range is "defined" in the axial direction. When an impact load is transmitted, the area between the reinforcing ribs 13 (i.e., the area of ​​the guide groove 6) is relatively thin. The weak point becomes the only controllable deformation starting point and folding point, which forces plastic deformation to strictly occur in this preset energy absorption zone, preventing the deformation from spreading disorderly to other key parts such as the hub or spokes 4. This achieves a precise and predictable energy absorption process, which dissipates most of the collision energy in a controllable manner, effectively avoiding brittle fracture of magnesium alloy caused by disordered deformation. As the collision continues, the plastic deformation of the guide block 7 deepens further, and the entire structure of the guide groove 6 is compressed along the axial direction. At this time, the compression of the energy absorption cylinder 9 enters the main stage, and the connecting cylinder 3 buckles and folds at the guide groove 6, further optimizing the crushing energy absorption process. During the deformation of the guide groove 6 area on the connecting cylinder 3, the energy absorption cylinder... As the lower end of the energy-absorbing cylinder 9 gradually approaches the steering column 5, and after the guide groove 6 area on the connecting cylinder 3 deforms until the lower end of the energy-absorbing cylinder 9 contacts the steering column 5, the energy-absorbing cylinder 9 located inside the connecting cylinder 3 begins to be squeezed by the steering column 5. The aluminum foam layer 10c inside it begins to be compressed, absorbing some of the impact energy and playing an auxiliary role in energy absorption and buffering. Subsequently, the aluminum foam layer 10b inside the energy-absorbing cylinder 9 begins to collapse on a large scale. Finally, the low-porosity aluminum foam layer 10a inside the energy-absorbing cylinder 9 is squeezed, and the energy absorption efficiency reaches its peak. During this stage, a portion of the energy is absorbed. The gap between the limiting ring 8 on the inner wall of the connecting cylinder 3 and the top of the steering column 5 gradually decreases with the overall deformation, preparing for the rigid limiting in the next stage.

[0042] When the bottom surface of the limiting ring 8 contacts the top surface of the steering column 5, the overall axial deformation of the connecting cylinder 3 reaches the safety limit. To prevent slippage at the moment of contact, both the bottom surface of the limiting ring 8 and the top surface of the steering column 5 are provided with triangular anti-slip protrusions 15. The two mesh to form a rigid stop, which instantly prevents the steering wheel frame from further intruding towards the driver's side, ensuring the survival space of the occupants. At the same time as the limiting occurs, the remaining impact energy is absorbed. Thus, the collision energy is dissipated, and the entire energy absorption and deformation process ends.

[0043] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various modifications can be made to the technical solutions of the present invention without departing from the spirit of the present invention or the scope of disclosure.

Claims

1. A magnesium alloy die-cast steering wheel frame, comprising a rim (1) and a hub, the hub comprising a hub body (2) and a connecting cylinder (3) connected to the bottom of the hub body (2), the hub body (2) being connected to the rim (1) via multiple spokes (4), and the lower part of the connecting cylinder (3) being connected to a steering column (5); characterized in that, It also includes an energy-absorbing structure and energy-absorbing components mounted on the connecting cylinder (3); The energy-absorbing structure includes a guide groove (6) and a guide block (7). The guide groove (6) is opened circumferentially along the outer wall of the connecting cylinder (3). Multiple guide blocks (7) are arranged in a ring array in the guide groove (6). The guide block (7) is a block with a right-angled triangular cross section. The upper side and inner side of the guide block (7) are fixed to the upper side wall and inner bottom wall of the guide groove (6) respectively. The inclined surface of the guide block (7) gradually approaches the inner bottom wall of the guide groove (6) from top to bottom. The two adjacent guide blocks (7) together with the guide groove (6) form a groove. The inner wall of the connecting cylinder (3) is connected to a limiting ring (8) corresponding to the guide groove (6). The energy-absorbing component includes an energy-absorbing cylinder (9) and an aluminum foam (10) located inside the connecting cylinder (3). The energy-absorbing cylinder (9) has an open top and the open end is connected to the bottom of the hub body (2). The closed end passes through the limiting ring (8) and has a gap with the steering column (5). The aluminum foam (10) is located inside the energy-absorbing cylinder (9).

2. The magnesium alloy die-cast steering wheel frame according to claim 1, characterized in that, The inner wall of the connecting cylinder (3) on the lower side of the energy-absorbing cylinder (9) is provided with multiple spline grooves (11), and the peripheral wall of the steering column (5) is provided with connecting splines (12) that correspond one-to-one with the spline grooves (11).

3. The magnesium alloy die-cast steering wheel frame according to claim 1, characterized in that, The depth of the guide groove (6) is 60%-70% of the wall thickness of the connecting cylinder (3). The outer walls of the connecting cylinder (3) on the upper and lower sides of the guide groove (6) are fitted with reinforcing ring ribs (13). The longitudinal section of the reinforcing ring ribs (13) is a vertical isosceles trapezoid with a smaller outer section and a larger inner section. The two reinforcing ring ribs (13) are symmetrical about the middle of the guide groove (6).

4. The magnesium alloy die-cast steering wheel frame according to claim 1, characterized in that, The guide groove (6) contains 8 guide blocks (7). The inner side of each guide block (7) is an arc-shaped surface that matches the inner bottom wall of the guide groove (6). The inner side of each guide block (7) intersects with the inner side of the adjacent guide block (7). The inner sides of the 8 guide blocks (7) intersect end to end to form a circle. The angle between the inclined surface and the top surface of each guide block (7) is 45 degrees.

5. The magnesium alloy die-cast steering wheel frame according to claim 4, characterized in that, Multiple guide blocks (7) and connecting cylinders (3) are integrally die-cast, with the outer end of the top surface of each guide block (7) transitioning to the outer wall of the connecting cylinder (3) by an arc; the outer end of the lower side surface of each guide groove (6) transitioning to the outer wall of the connecting cylinder (3) by an arc.

6. The magnesium alloy die-cast steering wheel frame according to claim 1, characterized in that, The top surface of the limiting ring (8) is flush with the upper side wall of the guide groove (6), and the bottom surface is flush with the lower side wall of the guide groove (6). The outer end of the top surface of the limiting ring (8) transitions to the inner wall of the connecting cylinder (3) by an arc, and the outer end of the bottom surface of the limiting ring (8) transitions to the inner wall of the connecting cylinder (3) by an arc.

7. The magnesium alloy die-cast steering wheel frame according to claim 1, characterized in that, The energy-absorbing cylinder (9) is a cylindrical body made of aluminum. The outer diameter of the energy-absorbing cylinder (9) matches the inner diameter of the limiting ring (8). Multiple annular grooves (14) are recessed from top to bottom on the outer wall of the energy-absorbing cylinder (9).

8. The magnesium alloy die-cast steering wheel frame according to claim 7, characterized in that, The aluminum foam (10) includes aluminum foam layer one (10a), aluminum foam layer two (10b) and aluminum foam layer three (10c) arranged from top to bottom inside the energy-absorbing cylinder (9). The porosity of aluminum foam layer one (10a) is 60%-65%, the porosity of aluminum foam layer two (10b) is 66%-74%, and the porosity of aluminum foam layer three (10c) is 75%-80%.

9. A magnesium alloy die-cast steering wheel frame according to claim 1, characterized in that, The bottom surface of the limiting ring (8) and the top surface of the steering column (5) are evenly distributed with triangular anti-slip protrusions (15).

10. A magnesium alloy die-cast steering wheel frame according to claim 1, characterized in that, The surface roughness Ra of the inclined surface of each guide block (7) is 3.2 μm-6.3 μm.

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