A heterogeneous material integrated manned lunar rover wheel hub and a forging-additive-re-forging integrated forming method thereof

Abstract

The application relates to a wheel hub of a manned lunar vehicle of an integrated heterogeneous material and a forging-additive-re-forging integral forming method thereof. The application aims to solve the problem that a wheel-shaped component of heterogeneous aluminum alloy materials is difficult to be integrally formed. The wheel hub of the manned lunar vehicle of the integrated heterogeneous material is connected by a rim and spokes, the rim is composed of a rim body, an outer ring assembly ring and strip-shaped reinforcing ribs, and the spokes are composed of a plurality of Y-shaped sheet-shaped thin plates, an axle assembly flange and a transition area. The method comprises the following steps: 1, blank preparation; 2, forging forming of the rim and the transition area; 3, additive interface finishing; 4, adding; 5, homogenization heat treatment; 6, integral forging forming; 7, aging strengthening treatment; and 8, mechanical processing forming of the wheel parts. The application is used for the wheel hub of the manned lunar vehicle of the integrated heterogeneous material and the forging-additive-re-forging integral forming thereof.

Description

Technical Field

[0001] This invention relates to the wheel hub of a manned lunar rover and its forming method. Background Technology

[0002] As my country's lunar exploration program enters a new phase, the manned lunar landing project has fully commenced related research. As one of the most crucial pieces of equipment in the manned lunar landing project, the manned lunar rover differs significantly from traditional lunar surface traversing equipment in terms of material selection, structural design, and performance requirements. The demands for high performance, long lifespan, and lightweight design of its various load-bearing components have increased further, thus placing higher demands on the design and manufacturing of these components.

[0003] Spacecraft wheel-shaped components, exemplified by the wheels of manned lunar rovers, possess the following characteristics: both their spokes and rims are thin-walled structures with numerous topological structures designed for lightweight requirements. This structure maximizes weight reduction while maintaining structural strength, thereby minimizing overall fuel consumption and maximizing load-bearing capacity. Furthermore, during service, the spokes play a primary supporting role and therefore require high strength, while the rims are subject to greater vibration and friction, necessitating high toughness and fatigue resistance. Different locations within the same component have varying performance requirements, necessitating the use of dissimilar materials to form the integral component.

[0004] High-strength aluminum alloys for aerospace applications mainly fall into two categories: 2xxx and 7xxx series. 2xxx series alloys exhibit good plasticity and toughness, with room temperature elongation exceeding 12%, while 7xxx series alloys possess high strength, reaching over 550 MPa at room temperature. Furthermore, the density of these aluminum alloys is only 2.8 g / cm³. 3 It can simultaneously meet the requirements of high strength and lightweight for aerospace components. The high toughness of 2xxx series aluminum alloys and the high strength of 7xxx series aluminum alloys can perfectly match the performance requirements of aerospace wheel-shaped components, making them very suitable for the preparation of aerospace wheel-shaped components.

[0005] However, current methods for forming dissimilar material components all have drawbacks. For example, methods that form the components separately and then weld them together result in weak weld joints that are prone to fatigue damage. Riveting connects two different materials, but the rivets significantly increase the component's weight. Additive manufacturing methods suffer from inherent defects that are difficult to eliminate, leading to a significant reduction in the component's mechanical properties. In summary, there is currently a lack of a method that can achieve integral forming of dissimilar materials while ensuring excellent microstructure and properties of the component. Summary of the Invention

[0006] This invention aims to solve the problem of the difficulty in integral forming of wheel-shaped components made of dissimilar aluminum alloy materials, and further provides an integral forming method for a manned lunar rover wheel hub made of dissimilar materials, which is formed by forging, additive manufacturing, and re-forging.

[0007] A one-piece manned lunar rover wheel hub made of dissimilar materials is composed of a rim and spokes. The rim consists of a rim body, an outer mounting ring, and strip-shaped reinforcing ribs. The rim body has a cylindrical structure. Both ends of the rim body have outer mounting rings. Multiple strip-shaped reinforcing ribs are axially arranged on the outer surface of the rim body, and these ribs are distributed in a ring at equal intervals. Both ends of each strip-shaped reinforcing rib are connected to the outer mounting ring. The spokes consist of multiple Y-shaped sheet plates, an axle mounting flange, and a transition area. The multiple Y-shaped sheet plates are distributed in a ring at equal intervals, with one end connected to the axle mounting flange and the other end connected to the inner edge of the transition area. The outer edge of the transition area is connected to the inner surface of the rim body. The multiple Y-shaped sheet plates and the transition area constitute the spokes.

[0008] The height H1 of the wheel rim body is 150mm to 250mm, the outer diameter D1 is 500mm to 600mm, and the wall thickness t1 is 1mm to 3mm; the thickness of the spokes is t2, t2 = (2 to 4)t1; the angle of the fork in the Y-shaped sheet plate is 30° to 60°, and the width of the branch is 15mm to 50mm; the inner diameter of the transition area is D2, D2 = (0.7 to 0.85)D1;

[0009] The wheel rim and transition area are made of 2xxx series aluminum alloy; the multiple Y-shaped sheet plates and axle assembly flanges are made of 7xxx series aluminum alloy.

[0010] A method for integral forming of a heterogeneous material manned lunar rover wheel hub by forging-additive manufacturing-re-forging is carried out according to the following steps:

[0011] I. Blank preparation:

[0012] Forged billets are obtained by processing forged billets;

[0013] The forged blank consists of a wheel rim body blank and a transition area blank, with the outer edge of the transition area blank connected to the inner surface of the wheel rim body blank.

[0014] II. Forging and forming of the wheel rim and transition area:

[0015] The forging billet and forging die are lubricated. The forging billet is then heated to the aluminum alloy forging temperature T1 and held at that temperature. At the same time, the forging die is preheated to temperature T2. The forging billet is then placed in the forging die and positioned. The forging billet is forged at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, it is cooled to room temperature in air to obtain the forging.

[0016] The forging consists of a wheel rim body forging and a transition area forging;

[0017] III. Additive Interface Trimming:

[0018] A ring-shaped bevel is machined on the forging in the transition zone;

[0019] IV. Additive Manufacturing:

[0020] Using an electric arc wire feeding additive manufacturing method, multiple Y-shaped sheet blanks and internal circular blanks are formed at the annular bevel of the forging in the transition region, and then ground and finished to obtain wheel composite material.

[0021] V. Homogenization heat treatment:

[0022] The wheel composite material is homogenized by heat treatment and then cooled to room temperature in air to obtain a homogenized wheel composite material.

[0023] VI. Overall forging and shaping:

[0024] The homogenized wheel composite material and forging die are lubricated. Then, the homogenized wheel composite material is heated to the aluminum alloy forging temperature T3 and held at that temperature. At the same time, the forging die is preheated to temperature T4. The homogenized wheel composite material is then placed in the forging die and positioned. The homogenized wheel composite material is forged as a whole at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, it is rapidly cooled to room temperature, and the flash is removed to obtain the final wheel forging.

[0025] VII. Time-sensitive processing:

[0026] The wheel forging is subjected to artificial aging strengthening treatment, and then cooled to room temperature in air to obtain the aged forging.

[0027] VIII. Machining and forming of wheel parts:

[0028] The wheel forgings after aging treatment are machined to obtain the integrated wheel hub of the manned lunar rover made of dissimilar materials.

[0029] The beneficial effects of this invention are:

[0030] This invention provides a method for integral forming of a manned lunar rover wheel hub made of dissimilar materials and its forging-additive-reforging integral forming process. The method includes forging a 2xxx series aluminum alloy wheel rim main body blank and a transition area blank, trimming the additive interface, adding a 7xxx series aluminum alloy Y-shaped sheet blank and an inner ring blank at the interface, homogenizing the obtained dissimilar material composite blank with heat treatment, and then integrally forging it. The final dissimilar material composite part is obtained by subsequent direct aging and machining.

[0031] This invention obtains a well-connected integral billet of dissimilar materials by adding dissimilar materials to a forging billet, and achieves integral forming of the dissimilar materials through integral forging. The resulting component has good integrity and uniform microstructure transition, and there will be no abrupt changes in microstructure that would cause excessive differences in performance in different areas. At the same time, the self-connection of dissimilar materials avoids the need for additional connecting structures to increase the weight of the overall component, thus meeting the requirements for lightweight components.

[0032] This invention reduces the difference in deformation resistance between two different materials during forging by heat treatment to homogenize the entire billet, improves the deformation coordination and microstructure uniformity of dissimilar material forging, and effectively prevents defects such as cracking of coarse additive structures during forging, thereby improving the quality of forgings.

[0033] This invention involves integral forging of homogenized dissimilar material billets, applying effective metal flow to the interior of the additive billet and at the interface between the dissimilar materials. Forging deformation improves the additive microstructure, forges together defects such as porosity and cracks, eliminates residual stress, increases the strength of the additive portion, and eliminates brittleness. Forging deformation also improves the interfacial microstructure, using interfacial metal flow to disrupt the interface boundary, forming an interfacial microstructure transition zone, promoting element diffusion on both sides of the interface, improving the microstructure uniformity on both sides of the interface, and preventing abrupt changes in microstructure and mechanical properties at the interface. Simultaneously, forging together defects such as poor bonding at the interface improves the interfacial bonding strength and prevents the interface from becoming a weak point in the component's performance.

[0034] This invention enables the integral forming of aluminum alloy components made of dissimilar materials, shortens the manufacturing cycle, further reduces the weight of components while ensuring that the component's microstructure and performance meet the standards, liberates the structural and material design thinking of lightweight aerospace components, effectively improves the material-performance matching degree of lightweight aerospace components, and provides a new direction for the design and preparation of lightweight components for next-generation spacecraft. Attached Figure Description

[0035] Figure 1 This is a perspective view of the wheel hub of the manned lunar rover made of dissimilar materials according to the present invention.

[0036] Figure 2 This is a cross-sectional view of the wheel hub of the manned lunar rover made of dissimilar materials according to the present invention.

[0037] Figure 3 This is a flowchart illustrating the forging-additive-reforging integral forming process of the wheel hub of a manned lunar rover made of dissimilar materials, as shown in Example 1.

[0038] Figure 4 This is a schematic diagram of the longitudinal section of the forging die cavity described in steps two and six of Example 1;

[0039] Figure 5The results of the finite element simulation of the forging process in step two of Example 1 are shown in Figure a, where a is before forging and b is the strain cloud diagram after forging.

[0040] Figure 6 This is a schematic diagram of the annular bevel processed in step three of Example 1, where A represents the annular bevel.

[0041] Figure 7 This is a schematic diagram of the interface position of additive manufacturing in step four of Example 1. a is a schematic diagram of the preparation of wheel composite material. A in the figure is the additive manufacturing interface position, and b is an enlarged view of position A in figure a.

[0042] Figure 8 The results of the finite element simulation of the integral forging process in step six of Example 1 are shown in Figure a, which is before forging and b is the strain cloud diagram after forging.

[0043] Figure 9 The image shows the finite element analysis of the wheel hub of the integrated manned lunar rover made of dissimilar materials prepared in Example 1 under load. a represents the deformation under load, and b represents the stress of the wheel under load. Detailed Implementation

[0044] Specific implementation method one, combined with Figure 1 and Figure 2 Description: This embodiment is a one-piece manned lunar rover wheel hub made of dissimilar materials, which is composed of a rim and spokes. The rim consists of a rim body 11, an outer ring mounting ring 12, and strip-shaped reinforcing ribs 13. The rim body 11 has a cylindrical structure. Both ends of the rim body 11 are provided with outer ring mounting rings 12. Multiple strip-shaped reinforcing ribs 13 are provided axially on the outer surface of the rim body 11, and the multiple strip-shaped reinforcing ribs 13 are distributed in a ring at equal intervals. Both ends of each strip-shaped reinforcing rib 13 are connected to the outer ring mounting ring 12. The spokes consist of multiple Y-shaped sheet plates 21, an axle mounting flange 22, and a transition area 23. The multiple Y-shaped sheet plates 21 are distributed in a ring at equal intervals, with one end connected to the axle mounting flange 22 and the other end connected to the inner edge of the transition area 23. The outer edge of the transition area 23 is connected to the inner surface of the rim body 11. The multiple Y-shaped sheet plates and the transition area 23 constitute the spokes.

[0045] The height H1 of the wheel rim body 11 is 150mm to 250mm, the outer diameter D1 is 500mm to 600mm, and the wall thickness t1 is 1mm to 3mm; the thickness of the spokes is t2, t2 = (2 to 4)t1; the angle of the fork of the Y-shaped sheet plate 21 is 30° to 60°, and the width of the branch is 15mm to 50mm; the inner diameter of the transition area 23 is D2, D2 = (0.7 to 0.85)D1;

[0046] The wheel rim and transition area 23 are made of 2xxx series aluminum alloy; the multiple Y-shaped sheet plates 21 and axle mounting flange 22 are made of 7xxx series aluminum alloy.

[0047] Principle: The wheel-shaped components of manned spacecraft serve in deep space environments such as the Moon or Mars. As a propulsion mechanism, they need to carry the entire deep space exploration equipment as well as manned and cargo vehicles. They are characterized by large load capacity, long service life, complex service environment, and great influence from rugged surface conditions and sand and gravel particles. At the same time, there is an extremely high demand for lightweight components.

[0048] Regarding material selection, the wheel rim is subject to significant vibration during service and requires high toughness, while the spokes provide structural support for the entire spacecraft and require high strength. Considering the overall load-bearing capacity and lightweight requirements of the component, the wheels are made of aluminum alloy. The rim and transition areas utilize high-toughness 2xxx series aluminum alloy, while the Y-shaped sheet metal and axle mounting flanges use high-strength 7xxx series aluminum alloy. Instead of mechanical connections such as riveting, the two materials are metallurgically bonded through forming, ensuring the strength of the joint and meeting the lightweight requirements of the component.

[0049] In terms of structural design, the outer mounting ring area of ​​the wheel rim is subjected to outward tension. Therefore, reinforcing ribs are arranged on the outer rim to reduce outer rim deformation, improve outer rim stiffness, and disperse stress. The spokes are the main load-bearing structure. Considering the overall lightweight requirements of the components, the spokes are designed as a Y-shaped distributed support structure to better disperse stress. At the same time, in order to adapt to the drive and steering mechanisms, the whole adopts a thin-walled spoke and barrel-shaped wheel rim structure, reserving space for the drive and steering mechanisms. In addition, the axle mounting flange area on the spokes is not in the center, but has a certain amount of offset.

[0050] The beneficial effects of this embodiment are:

[0051] This embodiment provides a method for integral forming of a manned lunar rover wheel hub made of dissimilar materials and its forging-additive-reforging integral forming process. The method includes forging a 2xxx series aluminum alloy wheel rim main body blank and a transition area blank, trimming the additive interface, adding a 7xxx series aluminum alloy Y-shaped sheet blank and an inner ring blank at the interface, homogenizing the obtained dissimilar material composite blank with heat treatment, and then performing integral forging. The final dissimilar material composite part is obtained by subsequent direct aging and machining.

[0052] This embodiment obtains a well-connected integral billet of dissimilar materials by adding dissimilar materials to a forging billet, and achieves integral forming of the dissimilar materials through integral forging. The prepared component has good integrity and uniform microstructure transition, and there will be no abrupt changes in microstructure that would cause excessive differences in performance in different areas. At the same time, the self-connection of dissimilar materials avoids the increase in weight of the overall component due to additional connection structures, which can meet the requirements for lightweight components.

[0053] This embodiment reduces the difference in deformation resistance between two different materials during forging by heat treatment to homogenize the entire dissimilar material billet, improves the deformation coordination and microstructure uniformity of dissimilar material forging, and effectively prevents defects such as cracking of coarse additive structures during forging, thereby improving the quality of forgings.

[0054] This embodiment involves integral forging of homogenized dissimilar material billets, which effectively applies metal flow to the interior of the additive billet and at the interface of the dissimilar materials. Forging deformation improves the additive microstructure, forges together defects such as porosity and cracks, eliminates residual stress, increases the strength of the additive portion, and eliminates brittleness. Forging deformation also improves the interfacial microstructure of the dissimilar materials, using interfacial metal flow to disrupt the interface boundary, forming an interfacial microstructure transition zone, promoting element diffusion on both sides of the interface, improving the microstructure uniformity on both sides of the interface, and preventing abrupt changes in microstructure and mechanical properties at the interface. At the same time, forging together defects such as poor bonding at the interface improves the interfacial bonding strength and prevents the interface from becoming a weak point in the component's performance.

[0055] This implementation method can achieve integral forming of aluminum alloy components made of dissimilar materials, shorten the manufacturing cycle, further reduce the weight of components while ensuring that the component's microstructure and performance meet the standards, liberate the structural and material design ideas of lightweight aerospace components, effectively improve the material-performance matching degree of lightweight aerospace components, and provide a new direction for the design and preparation of lightweight components for next-generation spacecraft.

[0056] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that: the transition radius between the spokes and the rim is R5 to R10; the width of the outer rim mounting ring 12 is 15mm to 25mm; the outer rim mounting ring 12 forms an angle of 100° to 150° with the outer wall of the rim body 11; the thickness of the outer rim mounting ring 12 is t3, where t3 = t1; the outer surface of the rim body 11 is provided with 5 to 11 strip-shaped reinforcing ribs 13 along the axial direction; the strip-shaped reinforcing ribs 13... The thickness is 3mm to 10mm; the wheel spokes are composed of 7 Y-shaped sheet plates 21, an axle mounting flange 22, and a transition area 23; the outer diameter of the axle mounting flange 22 is D3, D3 = (0.3 to 0.35)D1; the inner diameter of the axle mounting flange 22 is D4, D4 = (0.2 to 0.25)D1; the thickness of the axle mounting flange 22 is t4, t4 = (1 to 3)t2; the axle mounting flange 22 is offset 0mm to 15mm along the wheel hub axial direction. Other aspects are the same as in Specific Embodiment 1.

[0057] Specific Implementation Method 3: This implementation method provides a forging-additive-re-forging integral forming method for a one-piece manned lunar rover wheel hub made of dissimilar materials, which is carried out according to the following steps:

[0058] I. Blank preparation:

[0059] Forged billets are obtained by processing forged billets;

[0060] The forged blank consists of a wheel rim body blank and a transition area blank, with the outer edge of the transition area blank connected to the inner surface of the wheel rim body blank.

[0061] II. Forging and forming of the wheel rim and transition area:

[0062] The forging billet and forging die are lubricated. The forging billet is then heated to the aluminum alloy forging temperature T1 and held at that temperature. At the same time, the forging die is preheated to temperature T2. The forging billet is then placed in the forging die and positioned. The forging billet is forged at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, it is cooled to room temperature in air to obtain the forging.

[0063] The forging consists of a wheel rim body forging and a transition area forging;

[0064] III. Additive Interface Trimming:

[0065] A ring-shaped bevel is machined on the forging in the transition zone;

[0066] IV. Additive Manufacturing:

[0067] Using an electric arc wire feeding additive manufacturing method, multiple Y-shaped sheet blanks and internal circular blanks are formed at the annular bevel of the forging in the transition region, and then ground and finished to obtain wheel composite material.

[0068] V. Homogenization heat treatment:

[0069] The wheel composite material is homogenized by heat treatment and then cooled to room temperature in air to obtain a homogenized wheel composite material.

[0070] VI. Overall forging and shaping:

[0071] The homogenized wheel composite material and forging die are lubricated. Then, the homogenized wheel composite material is heated to the aluminum alloy forging temperature T3 and held at that temperature. At the same time, the forging die is preheated to temperature T4. The homogenized wheel composite material is then placed in the forging die and positioned. The homogenized wheel composite material is forged as a whole at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, it is rapidly cooled to room temperature, and the flash is removed to obtain the final wheel forging.

[0072] VII. Time-sensitive processing:

[0073] The wheel forging is subjected to artificial aging strengthening treatment, and then cooled to room temperature in air to obtain the aged forging.

[0074] VIII. Machining and forming of wheel parts:

[0075] The wheel forgings after aging treatment are machined to obtain the integrated wheel hub of the manned lunar rover made of dissimilar materials.

[0076] Specific Implementation Method Four: This implementation method differs from Specific Implementation Method Three in that: the processing described in step one is machining or upsetting-punching-expanding-ring rolling; the material of the forging billet described in step one is 2xxx series high-strength aluminum alloy; in step four, 7xxx series ultra-high-strength aluminum alloy is used as the additive manufacturing material; the forging molds described in steps two and six are the same. It is the same as Specific Implementation Method Three.

[0077] Specific Implementation Method Five: This implementation method differs from Specific Implementation Method Three or Four in that: the inner diameter of the annular bevel in step three is 55% to 70% of the outer diameter of the wheel rim body forging; the angle of the annular bevel is 20° to 40°; and the additive direction in step four is single-sided additive manufacturing on one side of the annular bevel. Everything else is the same as in Specific Implementation Method Three or Four.

[0078] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods Three to Five in the following ways: In step five, the wheel composite material is subjected to homogenization heat treatment at a temperature of 475℃~482℃ for 8h~24h; in step seven, the final wheel forging is subjected to artificial aging strengthening treatment at a temperature of 120℃~160℃ for 12h~24h; in step two, T1=T2, and T1=430℃~480℃; in step six, T3=T4, and T3=400℃~450℃. Everything else is the same as in Specific Implementation Methods Three to Five.

[0079] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods Three to Six in that: the height of the wheel rim body blank in Step One is 1.1 to 1.15 times the height of the final forged wheel rim body in Step Six; the outer diameter of the wheel rim body blank in Step One is 0.95 to 1 times the outer diameter of the final forged wheel rim body in Step Six; the wall thickness of the wheel rim body blank in Step One is 0.9 to 1 times the wall thickness of the final forged wheel rim body in Step Six; the thickness of the transition area blank in Step One is 3 to 6 times the thickness of the final forged spoke in Step Six; the inner diameter of the transition area blank in Step One is 3.8 to 4.1 times the inner diameter of the final forged ring in Step Six; and the transition radius between the wheel rim body blank and the transition area blank is R10 to R20. Everything else is the same as in Specific Implementation Methods Three to Six.

[0080] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods Three to Seven in the following ways: the height of the wheel rim body forging in step two is the same as the height of the wheel rim body final forging in step six; the outer diameter of the wheel rim body forging in step two is the same as the outer diameter of the wheel rim body final forging in step six; the wall thickness of the wheel rim body forging in step two is the same as the wall thickness of the wheel rim body final forging in step six; the thickness of the transition area forging in step two is the same as the thickness of the spoke final forging in step six; the inner diameter of the transition area forging in step two is 1.5 to 2 times the inner diameter of the ring final forging in step six; and the transition radius between the wheel rim body forging and the transition area forging is R10 to R20. Everything else is the same as in Specific Implementation Methods Three to Seven.

[0081] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods Three to Eight in that: the thickness of the Y-shaped sheet blank in step four is 1.5 to 3 times the thickness of the final forged spoke plate in step six; the thickness of the material superposition area formed at the joint of the bevel and the annular bevel of the Y-shaped sheet blank in step four is 1.1 to 3 times the thickness of the final forged spoke plate in step six; the branch width of the Y-shaped sheet blank in step four is 10 mm to 30 mm; and the inner diameter of the annular blank in step four is 1.2 to 1.4 times the inner diameter of the final forged annular ring in step six. Everything else is the same as in Specific Implementation Methods Three to Eight.

[0082] Specific Implementation Method Ten: This implementation method differs from Specific Implementation Methods Three to Nine in that: the wheel final forging in step six is ​​formed by connecting the wheel rim body final forging and the wheel spoke final forging; the wheel spoke final forging is composed of multiple Y-shaped sheet-like thin plate final forgings, a circular final forging, and a transition area final forging; the multiple Y-shaped sheet-like thin plate final forgings and the transition area final forging constitute the spoke plate final forging; the height of the wheel rim body final forging is (1.2~1.4)H1, the outer diameter is (1.05~1.2)D1, and the wall thickness is (10~35)t1; the thickness of the spoke plate final forging is (3~5)t2; the branch width of the Y-shaped sheet-like thin plate final forging is 25mm~60mm; the transition radius between the wheel rim body final forging and the wheel spoke final forging is R10~R20; the inner diameter of the circular final forging is (0.8~0.9)D4. The rest is the same as in specific implementation methods three to nine.

[0083] The beneficial effects of the present invention are verified using the following embodiments:

[0084] Example 1:

[0085] A one-piece manned lunar rover wheel hub made of dissimilar materials is composed of a rim and spokes. The rim consists of a rim body 11, an outer ring assembly ring 12, and strip-shaped reinforcing ribs 13. The rim body 11 has a cylindrical structure. Both ends of the rim body 11 are provided with outer ring assembly rings 12. The outer surface of the rim body 11 has seven strip-shaped reinforcing ribs 13 arranged axially along the axis. The seven strip-shaped reinforcing ribs 13 are distributed in a ring with equal spacing, and both ends of each strip-shaped reinforcing rib 13 are connected to the outer ring assembly ring 12. The spokes consist of seven Y-shaped sheet plates 21, an axle assembly flange 22, and a transition area 23. The seven Y-shaped sheet plates 21 are distributed in a ring with equal spacing. One end is connected to the axle assembly flange 22, and the other end is connected to the inner edge of the transition area 23. The outer edge of the transition area 23 is connected to the inner surface of the rim body 11. The seven Y-shaped sheet plates and the transition area 23 constitute the spokes.

[0086] The wheel rim body 11 has a height H1 = 176.7 mm, an outer diameter D1 = 515.7 mm, and a wall thickness t1 of 1 mm; the spoke thickness is t2, t2 = 3 mm; the Y-shaped sheet plate 21 has a fork angle of 40°, an upper branch width of 23 mm, and a lower branch width of 40 mm; the transition area 23 has an inner diameter D2, D2 = 360 mm to 420 mm; the transition radius between the spokes and the rim is R5; the outer ring mounting ring 12 has a width of 2 mm. 0mm; the outer ring assembly ring 12 forms a 135° angle with the outer wall of the wheel rim body 11; the thickness of the outer ring assembly ring 12 is t3, t3 = 1mm; the thickness of the strip-shaped reinforcing rib 13 is 5.4mm; the outer diameter of the axle assembly flange 22 is D3, D3 = 156mm; the inner diameter of the axle assembly flange 22 is D4, D4 = 126mm; the thickness of the axle assembly flange 22 is t4, t4 = 5mm; the axle assembly flange 22 is offset 7.5mm along the wheel hub axial direction;

[0087] The wheel rim and transition area 23 are made of 2219 aluminum alloy; the seven Y-shaped sheet plates 21 and the axle mounting flange 22 are made of 7050 aluminum alloy.

[0088] A method for integral forming of a heterogeneous material manned lunar rover wheel hub by forging-additive manufacturing-re-forging is carried out according to the following steps:

[0089] I. Blank preparation:

[0090] Forged billets are obtained by machining forging billets.

[0091] The forged blank consists of a wheel rim body blank and a transition area blank, with the outer edge of the transition area blank connected to the inner surface of the wheel rim body blank. The wheel rim body blank has a height of 255mm, an outer diameter of 557.8mm, and a wall thickness of 30mm. The transition area blank has a thickness of 42mm and an inner diameter of 446mm. The transition radius between the wheel rim body blank and the transition area blank is R20.

[0092] The forging billet is made of 2219 aluminum alloy;

[0093] II. Forging and forming of the wheel rim and transition area:

[0094] Graphite lubricant was sprayed onto the surfaces of the forging billet and the forging die. The forging billet was then heated to 480°C and held at 480°C for 90 minutes. Simultaneously, the forging die was preheated to 480°C. The forging billet was then placed in the forging die and positioned. The forging billet was forged at a pressing speed of 2.5 mm / s. Finally, it was cooled to room temperature in air to obtain the forging.

[0095] The forging consists of a wheel rim body forging and a transition area forging, with the outer edge of the transition area forging connected to the inner surface of the wheel rim body forging. The wheel rim body forging has a height of 227 mm, an outer diameter of 559.6 mm, and a wall thickness of 33 mm. The transition area forging has a thickness of 10 mm and an inner diameter of 188 mm. The transition radius between the wheel rim body forging and the transition area forging is R20.

[0096] III. Additive Interface Trimming:

[0097] A ring-shaped bevel is machined on the forging in the transition zone;

[0098] The inner diameter of the annular bevel is 360mm; the angle of the annular bevel is 30°.

[0099] IV. Additive Manufacturing:

[0100] Using 7050 aluminum alloy as the additive manufacturing material, the electric arc wire feeding additive manufacturing method is used to form 7 Y-shaped sheet blanks and circular blanks at the annular bevel of the forging in the transition area, and then grind and finish them to obtain the wheel composite material.

[0101] The thickness of the Y-shaped sheet blank is 25mm, and the thickness of the material superposition area formed at the joint of the bevel and the annular bevel of the Y-shaped sheet blank is 18mm; the width of the upper branch of the Y-shaped sheet blank is 18mm, and the width of the lower branch is 40mm; the inner diameter of the annular blank is 150mm.

[0102] V. Homogenization heat treatment:

[0103] The wheel composite material was homogenized and heat-treated for 8 hours at a temperature of 475℃, and then cooled to room temperature in air to obtain a homogenized wheel composite material.

[0104] VI. Overall forging and shaping:

[0105] The homogenized wheel composite material and forging die were lubricated. Then, the homogenized wheel composite material was heated to the aluminum alloy forging temperature of 450℃ and held at 450℃ for 90 minutes. At the same time, the forging die was preheated to 450℃. The homogenized wheel composite material was then placed in the forging die and positioned. The homogenized wheel composite material was forged as a whole at a pressing speed of 2.5 mm / s. Finally, it was rapidly cooled to room temperature and the flash was removed to obtain the final wheel forging.

[0106] The wheel final forging is formed by connecting the wheel rim body final forging and the wheel spoke final forging; the wheel spoke final forging is composed of 7 Y-shaped sheet-like thin plate final forgings, a circular final forging, and a transition area final forging; the 7 Y-shaped sheet-like thin plate final forgings and the transition area final forging constitute the spoke final forging.

[0107] The wheel rim body final forging has a height of 227mm, an outer diameter of 559.6mm, and a wall thickness of 33mm; the spoke final forging has a thickness of 10mm; the upper branch width of the Y-shaped sheet final forging is 34mm, and the lower branch width is 57mm; the transition radius between the wheel rim body final forging and the spoke final forging is R20; the inner diameter of the ring final forging is 110mm.

[0108] VII. Time-sensitive processing:

[0109] At a temperature of 120℃, the wheel forging was subjected to artificial aging treatment for 24 hours, and then cooled to room temperature in air to obtain the aged forging.

[0110] VIII. Machining and forming of wheel parts:

[0111] The aged wheel forgings were machined to obtain a one-piece manned lunar rover wheel hub made of dissimilar materials.

[0112] In step four, the additive manufacturing direction is single-sided additive manufacturing on one side of the annular bevel.

[0113] Step two is the same as the forging die described in step six.

[0114] Figure 3 This is a flowchart illustrating the forging-additive-reforging integral forming process of the wheel hub of a manned lunar rover made of dissimilar materials, as shown in Example 1.

[0115] Figure 4 This is a schematic diagram of the longitudinal section of the forging die cavity described in steps two and six of Example 1;

[0116] Figure 5 The figure shows the finite element simulation results of the forging process in step two of Example 1. a is the strain cloud diagram before forging and b is the strain cloud diagram after forging. As can be seen from the figure, the main deformation during the forging process is concentrated in the transition area between the wheel rim and the spoke. The deformation in this area is sufficient, and it has high performance after heat treatment. At the same time, the wheel rim is fully formed without forging defects.

[0117] Figure 6 This is a schematic diagram of the annular bevel processed in step three of Example 1, where A represents the annular bevel.

[0118] Figure 7This is a schematic diagram of the interface position of additive manufacturing in step four of Example 1. a is a schematic diagram of the preparation of wheel composite material. A in the figure is the additive manufacturing interface position, and b is an enlarged view of position A in figure a.

[0119] Figure 8 The figure shows the finite element simulation results of the integral forging process in step six of Example 1. a is before forging and b is the strain cloud diagram after forging. As can be seen from the figure, after integral forging, the metal in the additive region and the interface of the composite material both undergo significant deformation and metal flow, which can effectively improve the additive structure and interface bonding strength.

[0120] Figure 9 The figure shows the finite element analysis of the load-bearing condition of the integrated dissimilar material manned lunar rover wheel hub prepared in Example 1. a represents the deformation under load, and b represents the stress under load. As can be seen from the figure, the structural design of the integrated dissimilar material wheel hub of Example 1 can significantly reduce stress concentration at the spokes, improve the load-bearing capacity of the wheel under the same weight, and at the same time improve the stiffness of the rim, reduce the deformation of the rim under load, and effectively prevent premature failure of the wheel due to vibration and friction during service.

Claims

1. A method for integral forming of a manned lunar rover wheel hub made of dissimilar materials by forging, additive manufacturing, and re-forging, characterized in that... The wheel hub of the heterogeneous material integrated manned lunar rover is composed of a rim and spokes; the rim is composed of a rim body (11), an outer ring assembly ring (12), and strip-shaped reinforcing ribs (13); the rim body (11) is a cylindrical structure; both ends of the rim body (11) are provided with outer ring assembly rings (12); the outer surface of the rim body (11) is provided with multiple strip-shaped reinforcing ribs (13) along the axial direction, and the multiple strip-shaped reinforcing ribs (13) are distributed in a ring at equal intervals, and each strip-shaped reinforcing rib (13) Both ends are connected to the outer ring assembly ring (12); the spokes are composed of multiple Y-shaped sheet plates (21), an axle assembly flange (22) and a transition area (23); the multiple Y-shaped sheet plates (21) are distributed in a ring at equal intervals, and one end is connected to the axle assembly flange (22), and the other end is connected to the inner edge of the transition area (23), and the outer edge of the transition area (23) is connected to the inner surface of the wheel rim body (11); the multiple Y-shaped sheet plates and the transition area (23) constitute the spokes; The height H1 of the wheel rim body (11) is 150mm~250mm, the outer diameter D1 is 500mm~600mm, and the wall thickness t1 is 1mm~3mm; the thickness of the spokes is t2, t2=(2~4)t1; the angle of the fork of the Y-shaped sheet plate (21) is 30°~60°, and the width of the branch is 15mm~50mm; the inner diameter of the transition area (23) is D2, D2=(0.7~0.85)D1; The wheel rim and transition area (23) are made of 2xxx series aluminum alloy; the multiple Y-shaped sheet plates (21) and axle mounting flange (22) are made of 7xxx series aluminum alloy. The transition radius between the spokes and the rim is R5~R10; the width of the outer ring assembly ring (12) is 15mm~25mm; the outer ring assembly ring (12) forms an angle of 100°~150° with the outer wall of the rim body (11); the thickness of the outer ring assembly ring (12) is t3, t3=t1; the outer surface of the rim body (11) is provided with 5~11 strip-shaped reinforcing ribs (13) along the axial direction; the thickness of the strip-shaped reinforcing ribs (13) is 3mm~10mm; The spokes are composed of 7 Y-shaped sheet plates (21), an axle mounting flange (22), and a transition area (23); the outer diameter of the axle mounting flange (22) is D3, D3=(0.3~0.35)D1; the inner diameter of the axle mounting flange (22) is D4, D4=(0.2~0.25)D1; the thickness of the axle mounting flange (22) is t4, t4=(1~3)t2; the axle mounting flange (22) is offset 0mm~15mm along the hub axis; The above-mentioned method for forging-additive-re-forging integral forming of a one-piece manned lunar rover wheel hub made of dissimilar materials is carried out according to the following steps: I. Blank preparation: Forged billets are obtained by processing forged billets; The forged blank consists of a wheel rim body blank and a transition area blank, with the outer edge of the transition area blank connected to the inner surface of the wheel rim body blank. The height of the wheel rim body blank is 1.1 to 1.15 times the height of the final forged wheel rim body in step six; the outer diameter of the wheel rim body blank is 0.95 to 1 times the outer diameter of the final forged wheel rim body in step six; the wall thickness of the wheel rim body blank is 0.9 to 1 times the wall thickness of the final forged wheel rim body in step six; the thickness of the transition area blank is 3 to 6 times the thickness of the final forged spoke in step six; the inner diameter of the transition area blank is 3.8 to 4.1 times the inner diameter of the final forged ring in step six; the transition radius between the wheel rim body blank and the transition area blank is R10 to R20. II. Forging and forming of the wheel rim and transition area: The forging billet and forging die are lubricated. The forging billet is then heated to the aluminum alloy forging temperature T1 and held at that temperature. At the same time, the forging die is preheated to temperature T2. The forging billet is then placed in the forging die and positioned. The forging billet is forged at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, it is cooled to room temperature in air to obtain the forging. The forging consists of a wheel rim body forging and a transition area forging; T1=T2, and T1=430℃~480℃; The height of the main wheel rim forging is the same as the height of the final main wheel rim forging in step six; the outer diameter of the main wheel rim forging is the same as the outer diameter of the final main wheel rim forging in step six; the wall thickness of the main wheel rim forging is the same as the wall thickness of the final main wheel rim forging in step six; the thickness of the transition area forging is the same as the thickness of the final spoke forging in step six; the inner diameter of the transition area forging is 1.5 to 2 times the inner diameter of the final annular forging in step six; the transition radius between the main wheel rim forging and the transition area forging is R10 to R20. III. Additive Interface Trimming: A ring-shaped bevel is machined on the forging in the transition zone; The inner diameter of the annular bevel is 55% to 70% of the outer diameter of the wheel rim body forging; the angle of the annular bevel is 20° to 40°. IV. Additive Manufacturing: Using an electric arc wire feeding additive manufacturing method, multiple Y-shaped sheet blanks and internal circular blanks are formed at the annular bevel of the forging in the transition region, and then ground and finished to obtain wheel composite material. The thickness of the Y-shaped sheet blank is 1.5 to 3 times the thickness of the final forging of the spoke plate in step six; the thickness of the material superposition area formed at the joint of the bevel and the annular bevel of the Y-shaped sheet blank is 1.1 to 3 times the thickness of the final forging of the spoke plate in step six; the branch width of the Y-shaped sheet blank is 10 mm to 30 mm; the inner diameter of the annular blank is 1.2 to 1.4 times the inner diameter of the final forging of the annular ring in step six. V. Homogenization heat treatment: The wheel composite material was subjected to homogenization heat treatment at a temperature of 475℃~482℃ for 8h~24h, and finally cooled to room temperature in air to obtain homogenized wheel composite material. VI. Overall forging and shaping: The homogenized wheel composite material and forging die are lubricated. Then, the homogenized wheel composite material is heated to the aluminum alloy forging temperature T3 and held at that temperature. At the same time, the forging die is preheated to temperature T4. The homogenized wheel composite material is then placed in the forging die and positioned. The homogenized wheel composite material is forged as a whole at a pressing speed of 2.5 mm / s to 12.8 mm / s. Finally, it is rapidly cooled to room temperature, and the flash is removed to obtain the final wheel forging. T3=T4, and T3=400℃~450℃; The wheel final forging is formed by connecting the wheel rim body final forging and the wheel spoke final forging; the wheel spoke final forging is composed of multiple Y-shaped sheet-like thin plate final forgings, a circular final forging, and a transition area final forging; the multiple Y-shaped sheet-like thin plate final forgings and the transition area final forging constitute the spoke plate final forging; the height of the wheel rim body final forging is (1.2~1.4)H1, the outer diameter is (1.05~1.2)D1, and the wall thickness is (10~35)t1; the thickness of the spoke plate final forging is (3~5)t2; the branch width of the Y-shaped sheet-like thin plate final forging is 25mm~60mm; the transition radius between the wheel rim body final forging and the wheel spoke final forging is R10~R20; the inner diameter of the circular final forging is (0.8~0.9)D4. VII. Time-sensitive processing: Under conditions of 120℃~160℃, the wheel forgings are subjected to artificial aging strengthening treatment for 12h~24h, and then cooled to room temperature in air to obtain the aged forgings. VIII. Machining and forming of wheel parts: The wheel forgings after aging treatment are machined to obtain the integrated wheel hub of the manned lunar rover made of dissimilar materials.

2. The forging-additive-reforging integral forming method for a heterogeneous material integrated manned lunar rover wheel hub according to claim 1, characterized in that... The processing described in step one is machining or upsetting-punching-expanding-ring rolling process; the material of the forging billet described in step one is 2xxx series high-strength aluminum alloy; in step four, 7xxx series ultra-high-strength aluminum alloy is used as additive manufacturing material; the forging mold described in step two and step six is ​​the same.

3. The forging-additive-reforging integral forming method for a heterogeneous material integrated manned lunar rover wheel hub according to claim 1, characterized in that... In step four, the additive manufacturing direction is single-sided additive manufacturing on one side of the annular bevel.

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