Stirring friction tunnel forming device and method for enhancing bearing performance

Abstract

The invention provides a friction stir tunnel forming device and method for enhancing bearing performance, relates to the field of machining and inner flow channel forming, and aims to overcome the defects of an inner flow channel prepared through an existing friction stir tunnel forming technology in the aspects of structural bearing and fatigue performance. The non-rotating part is of a hollow structure, the rotating part is coaxially arranged in the non-rotating part, the non-rotating part comprises a clamping part, a step part and a shaft shoulder part, the bottom of the shaft shoulder part is provided with a reinforcing rib manufacturing part, the reinforcing rib manufacturing part is used for containing an inner runner surface material and providing forging pressure, and an inner runner surface with a reinforcing rib structure is manufactured. And a rounded rectangular inner flow channel is manufactured at the stirring needle part of the rotating part, so that the bearing efficiency and rigidity of the rotating part in an aerodynamic load and vibration environment are remarkably improved. And through different sections of the stirring needle part, the manufacturing requirements of the aerospace field on the lightweight and integrated heat management structure in the aspects of complex forms and multifunctional integration can be met.

Description

Technical Field

[0001] This invention relates to machining and internal flow channel forming, specifically to a friction stirring tunnel forming method for enhancing load-bearing performance. The forming device and method belong to the field of metal material manufacturing technology. Background Technology

[0002] With the rapid development of high-end equipment manufacturing technology, modern engineering structures, especially high-load, high-power-density systems, are facing increasingly severe integrated "thermal-mechanical-structural" challenges. Key functional components bear complex thermal and mechanical loads during operation, placing higher demands on efficient thermal management capabilities and structural load-bearing capacity. Adopting an active thermal protection structure with internal cooling channels is the core technological approach to achieving this goal, and its manufacturing quality directly determines the system's service performance and reliability. However, traditional processes such as casting, machining, and EDM have inherent defects such as insufficient machining accuracy, poor channel sealing, low design freedom, and significant material waste.

[0003] The emerging friction stir tunneling technology offers an innovative approach to manufacturing lightweight components with internal flow channels. Based on the principles of friction stir welding and machining, this technology utilizes a high-speed rotating and axially fed stirring pin to induce intense plastic deformation and thermo-mechanical coupling within the workpiece. This causes dynamic recrystallization and softening of the material at high temperature and high strain rate, resulting in its extrusion along the stirring pin's axis to form a hollow tunnel structure. Shoulders on the workpiece surface undergo rolling and forging effects under pressure, effectively sealing the tunnel's top. The entire process is completed in a solid state, avoiding the structural defects associated with traditional subtractive or welding methods, and directly producing a seamless, highly airtight internal flow channel structure.

[0004] However, due to the non-uniformity of material flow during tunnel forming, incomplete welding defects are prone to occur in the tunnel top area, making it a weak point in the structure under load, especially fatigue loads. Simultaneously, the radius of curvature of the transition region at the tunnel edge prepared by this method is too small, forming geometric stress concentration points. Under high-frequency vibration loads during system operation, the stress peak will significantly reduce the fatigue strength of the structure, posing a potential fatal risk. Summary of the Invention

[0005] This invention addresses the problems of weak inner channel surfaces and sharp, irregular shapes in the inner channels produced by traditional friction stir tunneling technology, which lead to stress concentration and reduced load-bearing capacity. Therefore, it proposes a method to enhance load-bearing capacity. A device and method for forming a stirring friction tunnel.

[0006] The technical solution adopted by the present invention to solve the above problems is as follows: This invention proposes a friction stir tunnel forming device with enhanced load-bearing performance, comprising a non-rotating component and a rotating component. The non-rotating component has a hollow structure, and the rotating component is coaxially disposed within the non-rotating component. The non-rotating component includes a clamping part, a step part, and a shoulder part. The bottom of the shoulder part is provided with a reinforcing rib manufacturing part, which is used to accommodate the inner flow channel surface material and provide forging pressure to create an inner flow channel surface with a reinforcing rib structure.

[0007] Furthermore, the side wall of the shoulder is provided with a discharge section for discharging material that has entered the interior of the non-rotating component. Furthermore, a conveying section is provided in the middle of the shoulder portion. Furthermore, the reinforcing rib manufacturing part includes, but is not limited to, rectangular, triangular, trapezoidal or semi-circular structures.

[0008] Furthermore, the rotating component includes a clamping part, a positioning part, a rotating step part, a smooth rod part, and a stirring needle part. The clamping part, positioning part, rotating step part, smooth rod part, and stirring needle part are connected as a whole from top to bottom. The stirring needle has an end-expanded thread structure for upward extraction of material.

[0009] Furthermore, the outer contour of the stirring needle includes, but is not limited to, rounded rectangles, spheres, or hemispherical structures.

[0010] Furthermore, the diameter of the threaded section of the stirring needle is 3-15mm, the pitch is 0.5-3mm, and the thread depth is 0.5-2.5mm.

[0011] The forming method based on the above-mentioned friction stir tunnel forming device for enhancing load-bearing performance includes the following steps: Step 1: Install the non-rotating component onto the non-rotating stator of the machining equipment spindle, and install the rotating component onto the spindle rotor. The stirring needle of the rotating component passes through the internal channel of the non-rotating component, and its end protrudes from the bottom surface of the shoulder of the non-rotating component. Step 2: Start the equipment and drive the rotating parts to rotate at a set speed. At the same time, the shoulder and reinforcing rib manufacturing parts are pressed against the surface of the metal substrate. The rotating stirring needle generates heat through friction with the substrate material, causing localized plasticization of the material. Step 3: Under the action of rotation, the threaded structure of the stirring needle generates an axial pumping effect, which draws the plasticized substrate material upward. The material drawn up first fills the reinforcing rib manufacturing part at the bottom of the shoulder; the material filled in the cavity of the reinforcing rib manufacturing part is compacted, forming a reinforcing rib on the upper surface of the metal substrate. Step 4: The extracted material continues to be conveyed through the non-rotating component to the discharge section, and is discharged outward from the discharge section.

[0012] Step 5: By rotating the stirring needle of the component, an internal flow channel with rounded corners is created inside the metal substrate.

[0013] Furthermore, the rotating part has a rotation speed of 200-10000 rpm and a travel speed of 1-1000 mm / min, and the travel speed must be matched with the rotation speed.

[0014] Furthermore, in step three, the cross-sectional shape of the reinforcing rib is determined by the shape of the reinforcing rib manufacturing part, which is rectangular, triangular, trapezoidal or semi-circular; in step five, the cross-sectional shape of the inner flow channel is determined by the shape of the stirring needle part, which is rounded rectangle, circle or semi-circle.

[0015] The beneficial effects of this invention are: 1. This invention, through the shoulder portion and reinforcing rib manufacturing portion set in a non-rotating component, simultaneously achieves densification of the inner flow channel surface and the manufacturing of equal-material reinforcing ribs during the friction stir tunnel forming process. This structure significantly improves the rigidity and load-bearing efficiency of the inner flow channel top plate without excessively increasing weight and volume, providing an integrated solution for high-heat-load equipment that combines efficient thermal management capabilities with excellent mechanical properties; 2. This invention, by designing a stirring needle with rounded corners, transforms the internal flow channel from a traditional sharp rectangle to a smooth, rounded rectangle, fundamentally eliminating geometric stress concentration points. This improvement effectively suppresses the initiation of fatigue cracks under severe vibration and high-maneuver overload conditions, significantly extending the fatigue life of critical hot-end components and meeting the stringent requirements of aerospace structures for high reliability and long lifespan. 3. This invention exhibits excellent process adaptability and morphological freedom, enabling the convenient fabrication of various flow channel layouts such as straight lines, rings, intersections, and conformal surfaces. This flexibility allows the technology to perfectly adapt to complex aerodynamic shapes and compact internal spaces, providing a key manufacturing means for realizing lightweight, high-performance customized heat dissipation systems. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of the present invention; Figure 2 This is a schematic diagram of the structure of the non-rotating component of the present invention; Figure 3 This is a schematic diagram of other structural forms of the non-rotating component reinforcing rib manufacturing section of the present invention; Figure 4 This is a schematic diagram of the structure of the rotating component of the present invention; Figure 5 This is a schematic diagram of other structural forms of the stirring needle of the rotating component of the present invention; Figure 6This is a schematic diagram showing the effect of the inner flow channel and its upper surface reinforcing ribs processed using the device and method of the present invention.

[0017] In the figure: 1-Non-rotating component, 101-Clamping part, 10101-Positioning clamping through hole, 102-Step part, 10201-Hollow channel, 103-Discharge part, 104-Conveying part, 105-Shoulder part, 106-Reinforcing rib manufacturing part; 2-Rotating component, 201-Clamping part, 20101-Side milling plane, 202-Positioning part, 203-Rotating step part, 204-Smooth rod part, 205-Stirring needle part; 3-Discharge material; 4-Reinforcing rib; 5-Inner flow channel; 6-Substrate. Detailed Implementation

[0018] Specific Implementation Method 1: This implementation method proposes a stirring friction tunnel forming device with enhanced load-bearing performance, such as... Figure 1 As shown, it includes a non-rotating component 1 and a rotating component 2. The non-rotating component 1 has a hollow structure, and the rotating component 2 is coaxially arranged inside the non-rotating component 1. The materials of the non-rotating component 1 and the rotating component 2 can be selected from high-speed tool steel, tungsten rhenium alloy, cemented carbide, polycrystalline cubic boron nitride, etc. The hardness of the selected materials should not be lower than that of the metal sheet. like Figure 2 As shown, the non-rotating component 1 includes: The clamping part 101 is used to be fixedly connected to the non-rotating stator part of the spindle of the machining equipment, including but not limited to friction stir welding machine, CNC milling machine, CNC machining center, etc.; the clamping part 101 is provided with a plurality of through holes 10101 evenly distributed along its circumference for positioning and clamping. The step portion 102 has a cylindrical hollow channel 10201 inside, which is used to cooperate with the rotating step portion 203 of the rotating component 2; The shoulder portion 105 has a flat bottom structure and a reinforcing rib manufacturing portion 106 at the bottom. The reinforcing rib manufacturing portion 106 is a cavity opened upward at the bottom of the shoulder portion 105 to accommodate the inner flow channel surface material and provide forging pressure to manufacture an inner flow channel surface with a reinforcing rib structure.

[0019] The discharge section 103 is a hole opened in the side wall of the shoulder section 105 for discharging material that has entered the non-rotating part 1.

[0020] The conveying section 104, located in the middle of the shoulder section 105, is used to convey the processing material upward and discharge the material through the discharge section. like Figure 3As shown, the reinforcing rib manufacturing section 106 includes, but is not limited to, rectangular, triangular, trapezoidal, or semi-circular structures. The reinforcing ribs with different cross-sectional shapes give the present invention high configuration adaptability and mission flexibility, enabling it to meet the aerospace industry's manufacturing requirements for lightweight, integrated thermal management structures in complex forms and multifunctional integration.

[0021] like Figure 4 As shown, the rotating component 2 includes a clamping part 201, a positioning part 202, a rotating step part 203, a smooth rod part 204, and a stirring needle part 205. The clamping part 201, the positioning part 202, the rotating step part 203, the smooth rod part 204, and the stirring needle part 205 are connected as a whole from top to bottom.

[0022] The clamping part 201 is used to connect to the rotating spindle rotor part of the machining equipment, including but not limited to friction stir welding machine, CNC milling machine, CNC machining center, etc. The clamping part 201 is provided with a side milling plane 20101 for side-fixed clamping.

[0023] The positioning part 202 is used to determine the position of the rotating component, ensuring a constant height difference between the rotating component and the non-rotating component. The rotating step part 203 has a cylindrical structure, and the gap between it and the hollow channel of the non-rotating component ranges from 0.5 to 10 mm. The optical rod portion 204 cooperates with the conveying portion 104 of the non-rotating component 1 to establish a channel for upward conveying of the substrate material.

[0024] The stirring pin 205 has an enlarged threaded end structure, used to achieve upward material extraction. The diameter of the threaded section of the stirring pin 205 is 3-15mm, the pitch is 0.5-3mm, and the thread depth is 0.5-2.5mm.

[0025] like Figure 5 As shown, the outer contour of the stirring pin 205 includes, but is not limited to, rounded rectangles, spheres, or hemispherical structures. By creating internal flow channels with different cross-sectional shapes using stirring pins 205, the load-bearing efficiency and stiffness under aerodynamic loads and vibration environments can be significantly improved.

[0026] Specific Implementation Method Two: This implementation method proposes a stirring friction tunnel forming method to enhance load-bearing performance, which is implemented using the forming device described in Specific Implementation Method One. The method includes the following steps: Step 1: Install the non-rotating component 1 on the non-rotating stator of the machining equipment spindle, and install the rotating component 2 on the spindle rotor. The stirring needle 205 of the rotating component 2 passes through the internal channel of the non-rotating component 1, and its end protrudes from the bottom surface of the shoulder 105 of the non-rotating component 1. Step 2: Start the equipment and drive the rotating part 2 to rotate at a set speed. The non-rotating part remains stationary and follows the rotation. Both move along the set path. At the same time, the shoulder 105 is pressed against the surface of the metal substrate 6. The rotating stirring needle 205 generates heat through friction with the substrate material, causing localized plasticization of the material. The substrate material includes, but is not limited to, common metal materials such as magnesium and magnesium alloys, aluminum and aluminum alloys, and copper and copper alloys.

[0027] Step 3: Under the action of rotation, the threaded structure of the stirring needle 205 generates an axial pumping effect, which draws the plasticized substrate material upward. The material drawn up first fills the shoulder 105 and the reinforcing rib manufacturing part 106. The material filled in the cavity of the reinforcing rib manufacturing part 106 is compacted, forming a reinforcing rib 4 on the upper surface of the metal substrate 6. Step 4: The material being extracted continues to reach the discharge section 103 via the conveying section 104 of the non-rotating component 1, and is discharged outward from the discharge section 103.

[0028] Step 5: By using the rounded corner structure around the stirring needle 205 of the rotating component 2, an inner flow channel (5) with a rounded corner structure is created inside the metal substrate (6).

[0029] Preferably, the cross-sectional shape of the reinforcing rib 4 is determined by the shape of the reinforcing rib manufacturing part 106, including but not limited to rectangular, triangular, trapezoidal or semi-circular structures; this gives the present invention a high degree of configuration adaptability and mission flexibility, and can meet the manufacturing requirements of the aerospace field for lightweight, integrated thermal management structures in terms of complex shapes and multi-functional integration.

[0030] Preferably, the cross-sectional shape of the inner flow channel 5 is determined by the shape of the stirring needle portion 205, including but not limited to rounded rectangles, circles, or semi-circular structures. Manufacturing inner flow channels with different cross-sectional shapes significantly improves their load-bearing efficiency and stiffness under aerodynamic loads and vibration environments.

[0031] Preferably, the rotating part has a rotation speed of 200-10000 rpm and a travel speed of 1-1000 mm / min, and the travel speed needs to be matched with the rotation speed.

[0032] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent substitutions, and improvements made to the above embodiments without departing from the scope of the present invention, based on the technical essence of the present invention and within the spirit and principles of the present invention, shall still fall within the protection scope of the present invention.

Claims

1. A friction stir tunnel forming device for reinforcing the bearing capacity, comprising a non-rotating part (1) and a rotating part (2), the non-rotating part (1) is a hollow structure, the rotating part (2) is coaxially arranged in the non-rotating part (1), the non-rotating part (1) comprises a clamping part (101), a stepped part (102) and a shaft shoulder part (105), characterized in that: The bottom of the shaft shoulder part (105) is provided with a reinforcing rib manufacturing part (106) for accommodating the inner flow channel surface material and providing forging pressure to manufacture the inner flow channel surface with reinforcing rib structure.

2. A friction stir tunnel forming device for enhanced load bearing properties according to claim 1, characterized in that: The sidewall of the shaft shoulder part (105) is provided with a discharging part (103) for discharging the material entering the interior of the non-rotating part (1).

3. A friction stir tunnel forming device for enhanced load bearing properties according to claim 1, wherein: The middle part of the shaft shoulder part (105) is provided with a conveying part (104).

4. The device according to claim 1, wherein: The reinforcing rib manufacturing part (106) includes but is not limited to rectangular, triangular, trapezoidal or semicircular structure.

5. The friction stir tunnel forming device of claim 1, wherein: The rotating part (2) includes a clamping part (201), a positioning part (202), a rotating step part (203), a light pole part (204) and a stirring needle part (205), which are connected in sequence from top to bottom, and the stirring needle (205) is an end expansion threaded structure for upward extraction of the material.

6. A friction stir tunnel forming device for enhanced load bearing properties according to claim 1, wherein: The outer contour of the stirring needle (205) includes but is not limited to a rounded rectangular, spherical or semispherical structure.

7. The device according to claim 1, wherein: The diameter of the threaded segment of the stirring needle (205) is 3-15mm, the pitch is 0.5-3mm, and the thread depth is 0.5-2.5mm.

8. A method of enhancing the load carrying capacity of a friction stir tunnel forming device according to any one of claims 1 to 7, characterised in that: The method comprises the following steps: Step one, install the non-rotating part (1) on the main shaft non-rotating stator of the machining equipment, and install the rotating part (2) on the main shaft rotor, the stirring needle part (205) of the rotating part (2) passes through the internal passage of the non-rotating part (1), and the end thereof protrudes from the bottom surface of the shaft shoulder part (105) of the non-rotating part (1); Step two, start the equipment, drive the rotating part (2) to rotate at a set speed, at the same time, press the shaft shoulder part (105) and the reinforcing rib manufacturing part (106) against the surface of the metal substrate (6), the rotating stirring needle part (205) generates heat by friction with the material of the substrate (6), and the local material is plasticized; Step three, under the action of rotation, the threaded structure of the stirring needle part (205) produces an axial pumping effect, and the plasticized substrate material is extracted upward, and the extracted material is first filled into the reinforcing rib manufacturing part (106) at the bottom of the shaft shoulder part (105); the material filled in the reinforcing rib manufacturing part (106) is compacted to form a reinforcing rib (4) on the upper surface of the metal substrate (6); Step four, the continuously extracted material reaches the discharging part (103) through the conveying part (104) of the non-rotating part (1), and is discharged outward from the discharging part (103). Step five, the stirring needle part (205) of the rotating part (2) makes the inner flow channel (5) with a rounded structure in the metal substrate (6).

9. A method according to claim 8, wherein the friction stir tunnel forming process is reinforced by the use of a backing plate. The rotation speed of the rotating part (2) is 200-10000rpm, and the travel speed is 1-1000mm / min, which needs to be matched with the rotation speed.

10. The method of friction stir tunnel forming for enhanced load bearing properties of claim 1, wherein: In step three, the cross-sectional shape of the reinforcing rib (4) is determined by the shape of the reinforcing rib manufacturing part (106), which is rectangular, triangular, trapezoidal or semicircular; in step five, the cross-sectional shape of the inner flow channel (5) is determined by the shape of the stirring needle part (205), which is rounded rectangular, circular or semicircular.

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