Welding tool, system and welding method for friction lap joint girth welding of metal / polymer assembly of rotary body structure

Abstract

The invention relates to a welding tool, system and method for friction lap joint girth welding of a metal / polymer assembly of a rotary body structure. The welding tool comprises an annular friction part, a supporting heat dissipation part and a mounting part which are sequentially arranged, wherein the annular friction part is used for generating heat through friction with a rotary body metal piece, the supporting heat dissipation part is used for supporting and heat dissipation, and the mounting part is used for being connected with a welding machine. The welding system comprises a welding tool, a clamping tool, a workbench, a temperature measuring device and a force collecting device. The clamping tool is used for fixing the metal / polymer assembly of the rotary body structure on the workbench, the temperature measuring device comprises a thermocouple used for collecting the temperature of a metal / polymer to-be-connected surface area, and the force collecting device comprises a force sensor used for collecting axial welding pressure. Compared with the prior art, the method has the advantages that the design process is simple, the welding process is controllable and more stable, the efficiency is higher, heating power distribution is concentrated, circumferential distribution is uniform, and high-quality connection of the revolving body metal / polymer assembly and related special-shaped structures can be achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of complex structure dissimilar material connection, and in particular to a welding tool, system and welding method for friction lap ring welding of metal / polymer components of a rotating body structure. Background Art

[0002] Metal / polymer composite structures have unique properties that cannot be provided by a single material, and are in great demand in aerospace, biomedicine and other fields. However, the huge differences in the thermal, physical and chemical properties of metals and polymers make it difficult to connect metals / polymers. Especially for complex structures such as valves, it is necessary to design connection tools and connection processes to meet connection requirements. Mechanical connection, bonding and welding / thermal connection are currently the commonly used connection methods for metals / polymers.

[0003] The mechanical connection process is simple and easy to use, but the connection part needs pretreatment, which increases the process, is prone to stress concentration and other problems, and introduces additional mass. Adhesion can achieve non-destructive connection, and the connection surface process is highly uniform, but the bonding process takes a long time and is complex, and it is very easy to fail in extreme environments such as humidity and high temperature. At present, the main methods of welding / thermal connection include ultrasonic welding, laser welding, friction lap welding, etc. The connection principle is to heat the metal / polymer interface so that the polymer is softened and melted by heat, and further form macro / micro mechanical bonding and chemical bonding with the metal surface to be connected, so as to achieve high-quality connection. It should be pointed out that ultrasonic welding is often used for thin plate welding. For metal / polymer connections with thick plates or complex structures such as valve structures, ultrasonic welding cannot be achieved for the time being; laser welding can connect metal / polymer structures with a larger size range, but due to the large heat input of laser welding and the high temperature of the welding interface, it is easy to cause the polymer material at the interface to overheat and degrade, resulting in defects that affect the connection quality. .

[0004] At present, the research on metal / polymer connection is mostly focused on the flat plate structure with simple structure and easy operation. The patent with publication number CN109834383A discloses a method and device for overlapping friction lap spot welding of titanium alloy / ultra-high molecular weight polyethylene, which uses a titanium alloy flat plate with surface structure design and ultra-high molecular weight polyethylene to achieve high-quality connection between metal and polymer by overlapping friction lap spot welding. The end of the rotating tool involved is circular, smaller than the width of the titanium alloy flat plate to be connected, the inclination angle between the rotating tool and the metal surface is 0°, the rotating tool speed is between 500rpm and 4000rpm, the pressing speed is between 0.5mm / min and 6mm / min, the overall porosity of the designed porous rough layer on the titanium alloy surface is limited to between 20% and 90%, and the thickness of the porous rough layer on the surface is limited to between 0.1mm and 5mm. It has a typical representative role in the metal / polymer welding of flat plate structure.

[0005] At present, the research on metal / polymer connection of complex structures such as rotating structures is relatively lacking. The patent with publication number CN111976152A discloses an assembly and composite welding method based on pipe fittings and metal-plastic composite pipes. It uses injection molding and electromagnetic induction heating and other methods to achieve metal and polymer connection of complex structures, but its equipment is complex and the process is cumbersome, which has great limitations. In addition, for the connection of rotating metal / polymer valve components, the commonly used methods are hot pressing, gluing, etc., but the above methods will crack after product processing, and have many disadvantages such as low yield rate, poor product weather resistance, complex process, long process time, and high cost.

[0006] Patent publication number CN116494446A discloses a preparation method for improving the interface performance of polytrifluorochloroethylene and metal matrix during thermoplastic molding. This method uses modified polytrifluorochloroethylene and metal matrix to form an integral body through hot pressing, which can improve the interface performance to a certain extent, but the process is complicated and takes a long time. Summary of the invention

[0007] The purpose of the present invention is to provide a welding tool, system and welding method for friction lap ring welding of metal / polymer components of a rotating structure.

[0008] The objective of the present invention can be achieved through the following technical scheme: a welding tool for friction lap ring welding of a rotating structure metal / polymer assembly, comprising an annular friction portion for generating heat by friction with a rotating metal part in the rotating structure metal / polymer assembly, a supporting and heat dissipating portion for supporting and dissipating heat, and a mounting portion for connecting to a welding machine, which are arranged in sequence.

[0009] Preferably, the annular friction portion is a hollow annular rotating body.

[0010] In the present invention, the portion of the bottom surface of the welding tool used to generate heat by friction with the upper surface of the metal part is preferably in a circular shape, and its size is determined according to the size of the metal / polymer components to be welded, so as to achieve uniform thermal distribution on the metal / polymer connection surface and achieve high-quality bonding.

[0011] Further preferably, the outer diameter of the annular friction portion does not exceed the maximum outer diameter D of the rotating metal part to be welded.

[0012] More preferably, the outer diameter of the annular friction portion is 0.4D to 0.9D.

[0013] More preferably, the inner diameter of the annular friction portion is 0.3D to 0.7D.

[0014] Preferably, the thickness of the annular friction portion is not less than the thickness H of the rotating metal part to be welded.

[0015] Further preferably, the thickness of the annular friction portion is 1.0H to 3.0H.

[0016] In the present invention, the size of the welding tool is determined according to the actual connection area and shape, structure and size of the metal / polymer components to be connected, and the maximum diameter of the welding tool should be smaller than the maximum size of the metal friction surface.

[0017] In the present invention, the structural dimensions of the friction ring are related to the connecting surface dimensions of the valve structure to be welded, the shape of the valve structure and the actual interface connection requirements.

[0018] More preferably, the annular friction portion has an outer diameter between 30 mm and 150 mm, an inner diameter between 20 mm and 130 mm, and a thickness between 2 mm and 15 mm.

[0019] Preferably, the annular friction portion has an outer diameter between 40 mm and 120 mm, an inner diameter between 30 mm and 110 mm, and a thickness between 4 mm and 8 mm.

[0020] Preferably, the bottom surface of the annular friction portion is smooth or provided with textures, and preferably the bottom surface is smooth.

[0021] In the present invention, the bottom surface of the welding tool can be designed with patterns and shapes to promote heat generation and regulate heat distribution during welding, thereby adjusting the flow behavior of the polymer melt during welding.

[0022] Further preferably, the bottom surface texture of the annular friction portion includes a thread structure or a groove structure.

[0023] In the present invention, the design of the bottom pattern or structure of the welding tool can be selected according to actual welding requirements, including but not limited to thread structure, groove structure, etc., and the specific shape, size and number of the bottom pattern or structure are not limited.

[0024] Preferably, the rotor structure metal / polymer component comprises a rotor metal part and a rotor polymer part, and the rotor metal part is provided with a rotor groove for mounting the rotor polymer part.

[0025] Preferably, the supporting heat dissipation portion has a diameter smaller than that of the annular friction portion.

[0026] Preferably, the support heat dissipation portion is provided with a heat dissipation groove for increasing the heat dissipation area.

[0027] Preferably, the supporting and heat dissipating part and the mounting part of the welding tool are both provided with textures, while the annular friction part is not provided with textures.

[0028] In the present invention, the welding tool can be designed with structures and patterns on each section of the longitudinal structure to increase the heat dissipation area during the welding process, and the design of the structures and patterns is not limited.

[0029] Preferably, the welding tool is made of cemented carbide, tungsten-rhenium alloy, or H13 steel.

[0030] In the present invention, the material selection of the welding tool can be determined according to the metals to be connected, and generally cemented carbide (such as tungsten carbide cobalt-based alloy), tungsten-rhenium alloy, H13 steel, etc. are selected.

[0031] Further preferably, the cemented carbide comprises tungsten carbide cobalt-based alloy.

[0032] A welding system for friction lap ring welding of metal / polymer components of a rotating structure, comprising a welding tool, a clamping tool, a workbench, a temperature measuring device and a force acquisition device;

[0033] The clamping tool is used to fix the metal / polymer component of the rotating structure on the workbench, the temperature measuring device includes a thermocouple for collecting the temperature of the metal / polymer surface area to be connected, and the force collection device includes a force sensor for collecting axial welding pressure.

[0034] In the present invention, the shape of the clamping tool is determined according to the shape of the rotating metal / polymer component to be welded. Its function is to ensure the stability of the metal / polymer valve component during welding, so the clamping tool needs to restrict the metal / polymer valve component from moving and tilting, and at the same time, it needs to have the freedom of longitudinal movement.

[0035] Preferably, the welding system for friction lap ring welding of metal / polymer components of a rotating structure further comprises a heating device for preheating the metal / polymer surface area to be connected.

[0036] Further preferably, the heating device includes a hot air gun and a heating plate.

[0037] Preferably, the thermocouple is a flexible thermocouple.

[0038] Further preferably, the thermocouple is a K-type thermocouple.

[0039] Preferably, the temperature measuring device also includes a signal acquisition device, a working computer and software installed on the working computer.

[0040] Preferably, the workbench is provided with threaded holes, and the clamping tool is detachably mounted on the workbench by bolts.

[0041] Preferably, the workbench is a square thick plate.

[0042] Preferably, the workbench is detachably mounted on the friction lap welding lathe.

[0043] In the present invention, the workbench is a square thick plate of a certain size, and its size can be determined based on the actual welding process on the basis of being able to bear the strength and rigidity required for welding. The workbench needs to have regularly distributed threaded holes of a certain size for fixing the clamping tool by bolts, and the distribution spacing, size and number of the threaded holes must match the hole structure used for fixing the position of the clamping tool. The workbench must be able to be easily disassembled and assembled on the friction lap welding lathe.

[0044] The tool and method of the present invention fix the rotating metal / polymer assembly on the workbench through a clamping tool, and rotate the rotating welding tool designed specifically on the metal friction surface, thereby generating heat to soften the polymer in the area near the surface to be connected. Under the action of welding pressure, the softened polymer can be immersed in the structure of the surface roughness layer generated by the surface treatment of the metal, thereby forming an interface bond. The temperature field and force in the welding process can be monitored and data collected through thermocouples, temperature measuring devices and force measuring devices. The thermal conditions in the welding process can be optimized by analyzing the above data, and the rotation speed, pressing speed, welding time, etc. of the welding tool can be adjusted to improve the welding quality of the metal / polymer assembly.

[0045] A welding method for friction lap ring welding of a metal / polymer component of a rotating structure is performed using the above welding system and comprises the following steps:

[0046] S1: embedding the rotating polymer part into the rotating groove of the rotating metal part, so that the rotating polymer part is in close contact with the surface to be connected of the rotating groove;

[0047] S2: Fix the metal / polymer components of the rotating structure with fixed position relationship on the workbench using a clamping tool;

[0048] S3: The welding tool is rotated and pressed down on the upper surface of the rotating metal part. The welding tool and the surface of the rotating metal part generate heat through friction, so that the rotating polymer part and the rotating groove surface to be connected are effectively connected.

[0049] In the present invention, in step S3, the friction heat generated by the welding tool and the upper surface of the rotating metal part reaches the metal / polymer surface to be connected through metal heat conduction, so that the interface temperature exceeds the melting temperature of the polymer material, so that the polymer near the surface to be connected is in a molten state and has fluidity, which can achieve the infiltration and bonding of the polymer to the metal. The highest temperature of the rotating metal part during the welding process should be lower than the melting point of the metal.

[0050] Preferably, the average welding force in the welding process of step S3 is 1 to 12 kN.

[0051] Preferably, in step S3, the rotation speed of the welding tool is 200 rpm to 2000 rpm, the pressing speed is between 0.1 mm / min and 10 mm / min, and the interface temperature between the polymer part of the rotating body and the connecting surface of the rotating body groove is controlled to be 180°C to 450°C during the welding process.

[0052] In the present invention, the selection of the temperature at the interface between the groove structure of the rotating metal valve and the polymer material to be connected depends on the thermal properties of the polymer material. The interface temperature should be high enough to allow the polymer material to have sufficient fluidity, to achieve effective flow and to be infiltrated and bonded with the metal; at the same time, if the temperature is too high, the polymer material will be degraded, which is harmful to the interface bonding. Therefore, the interface temperature should be selected and controlled according to the polymer material used to ensure the effective flow of the polymer and the infiltration of the metal without being degraded by heat.

[0053] Further preferably, in step S3, the rotation speed of the welding tool is 400 rpm to 1000 rpm, the pressing speed is between 0.8 mm / min and 4 mm / min, and the welding time is controlled between 5 s and 60 s.

[0054] In the present invention, if the rotation speed of the welding tool is too high and the pressing speed is too slow during the welding process, it is easy to cause the metal / polymer interface temperature to be too high. At the same time, the high temperature will cause the metal to deform violently, and high-quality interface connection cannot be achieved. If the rotation speed of the welding tool is too low and the pressing speed is too fast, the interface temperature will be too low, the heat will be insufficient, the polymer material will be broken under pressure, and connection cannot be achieved.

[0055] Further preferably, the pressing amount of the welding tool in step S3 is related to the thickness d of the structure of the rotating metal part to be welded, and the range of the pressing amount is: between 0.05×d and 0.3×d.

[0056] In the present invention, the selection of the pressing amount of the welding tool should be based on whether the polymer melt can fill the surface pore structure of the metal surfaces to be connected and fill the fitting gap around the surfaces to be connected, and is therefore related to the volume consumption of the polymer used for filling.

[0057] More preferably, the welding pressure range is between 0.2 mm and 5 mm.

[0058] Preferably, in step S1, the surface to be connected of the groove of the rotating body is prepared with a surface active rough layer through surface treatment.

[0059] In the present invention, the surface to be connected of the groove structure of the metal valve needs to be treated to prepare an active rough layer before welding, and the active rough layer is conducive to the combination of metal and polymer.

[0060] Further preferably, the surface treatment method includes metal anodizing, sandblasting, plasma treatment, and laser etching.

[0061] In the present invention, whether to use a heating device to preheat the area to be connected of the metal / polymer component can be determined according to the properties of the material used, and the polymer can be softened by preheating.

[0062] Preferably, a preheating step is provided between steps S2 and S3.

[0063] Further preferably, a heating device is used to preheat the surface area of ​​the metal / polymer component of the rotating body structure to be connected to soften the polymer material.

[0064] More preferably, the preheating temperature ranges from 50°C to 300°C.

[0065] Preferably, the rotating metal part is provided with a tunnel for the thermocouple to pass through.

[0066] Further preferably, the cross-sectional shape of the tunnel is square or circular, the tunnel is arranged along the radial direction of the rotating metal part, and the end point is on the metal side of the metal / polymer interface.

[0067] More preferably, when the cross-sectional shape of the tunnel is square, the side length is 1 to 2 mm, and when the cross-sectional shape of the tunnel is circular, the radius is 0.5 to 1 mm.

[0068] Preferably, the clamping tool comprises an annular pit structure, and the rotating body polymer part can be embedded in the annular pit structure.

[0069] In the present invention, before the surface treatment of the metal part structure and the welding step, a plurality of square or circular tunnels with a side length of 1 to 2 mm (or a radius of 0.5 to 1 mm) are manufactured on the metal valve structure by mechanical processing, and the end of the tunnel is on the metal side close to the metal / polymer interface. During the welding process, a flexible thermocouple (such as a K-type thermocouple) is inserted into the tunnel to realize the interface temperature collection and measurement during the welding process.

[0070] Further preferably, a plurality of tunnels are provided on the rotating metal member.

[0071] In the present invention, the tunnels for placing thermocouples can be processed in multiple numbers on a metal part, multiple thermocouples can be placed, and the interface temperatures at multiple positions can be measured to analyze the temperature evolution and distribution of the welding process.

[0072] In the present invention, the metal / polymer components to be connected are combined in a suitable matching manner, wherein the metal surface connected to the polymer is pre-treated to have surface activity and a rough structure, and then the valve assembly is fixed on the workbench by a clamping tool, the welding tool is located directly above the metal / polymer component structure, the thermocouple and the temperature measuring device are connected to the area near the metal / polymer surface to be connected, and the pressure sensor is arranged below the clamping tool or a force sensor collector provided by the welding equipment is used.

[0073] In welding technology, friction lap welding has the advantages of flexible and simple process, high controllability, and smooth and stable heat input. The present invention uses it for metal / polymer connections with complex structures and sizes.

[0074] Although the applicability of friction lap welding in the field of metal and polymer connection of flat structure has been fully confirmed, due to the shape and size limitations of the complex structure of the rotating body, it is difficult to achieve uniform temperature distribution in the welding area during the friction welding process, and the consistency of the welding conditions is also difficult to ensure. At the same time, it is difficult to achieve the regulation of the thermal behavior (such as flow behavior) of the polymer melt at the interface during the welding process and the directional interface bonding in the specified temperature zone. The temperature gradient control at the entire interface and the directional regulation of the melting and recrystallization of the polymer material in the corresponding area cannot be achieved. In addition, in the friction welding of complex structures, local synchronous heating and pressurization of designated key parts is another problem. Since flat plate welding is only applicable to the connection of a relatively single position, it cannot be transplanted to the welding of metal and polymer parts in higher spatial dimensions. Therefore, flat plate friction lap welding technology is usually not used for high-quality welding of metal / polymer components with complex structures of rotating bodies. The present invention can achieve directional control of the temperature zone of the metal-polymer designated area of ​​the rotating body structure by optimizing the design of the welding tools, and simultaneously apply heat to the key local areas to be combined to ensure the consistency of the working conditions and performance of the areas to be connected, and can avoid the formation of interface defects to a limited extent; by adjusting the welding process, the thermal process and thermal behavior of the interface polymer materials can be controlled to further ensure the formation of a defect-free interface; through the coordination of various parts and processes in the welding process, a stable combination of metal-polymer in multiple regions can be achieved. The present invention realizes efficient, simple, and high-quality connection of metal / polymers of complex structures by controlling the welding process and designing and developing welding tools and clamping tools, and successfully applies the welding method from plane welding of simple working conditions to three-dimensional space dimensions, and can simultaneously overcome multiple technical difficulties that cannot be achieved by flat plate welding.

[0075] Compared with the prior art, the present invention has the following beneficial effects:

[0076] 1. The present invention realizes high-quality direct connection between metal / polymer components of complex structures represented by a rotating body, such as a valve structure, by friction lap ring welding. While realizing high-quality connection of metal / polymer components of the rotating body structure, the production efficiency of metal / polymer components of the composite structure can be greatly improved.

[0077] 2. The present invention has a simple process, high process controllability, and can simultaneously monitor the temperature and downward pressure of the welding process. It is a welding tool and welding method for friction lap welding of rotating metal / polymer components that can effectively avoid interface defects in the metal / polymer connection process.

[0078] 3. The present invention realizes friction lap welding of metal / polymer components of complex structures such as rotating bodies by designing a unique hollow annular rotating body welding tool.

[0079] 4. The process of the present invention is simple, the welding process is controllable and more stable, the efficiency is higher, the heat distribution is concentrated and the circumferential distribution is uniform, and it can achieve high-quality connection of rotating metal / polymer components and related special-shaped structures. After welding is completed, a strong macro / micro mechanical bite and chemical bonding can be formed between the connection surfaces of the metal / polymer valve components to obtain a high-strength, high-quality connection surface.

[0080] 5. The present invention has a wide range of applications and is suitable for the connection of metal / polymer components in the field of friction lap welding. The welding process does not destroy the metal / polymer connection interface. In most cases, there is no need to pretreat the metal or polymer connection surface. The hollow circular rotating body welding tool can be designed and selected according to actual needs. The size selection is flexible and can be used for direct connection between complex structural components of various metals and polymers.

[0081] 6. The device of the present invention is simple and flexible to operate. The workbench used in the welding method is flexible to disassemble and assemble and has low cost. The welding tools are easy to manufacture and replace. The clamping tools have a simple structure. Other equipment is simple and flexible to operate, easy to disassemble and assemble, and can be reused.

[0082] 7. The welding process of the present invention is stable. The welding tools involved and the clamping tools related to the welding method work together to make the welding process efficient and stable, so that the corresponding metal / polymer valve components will not become unstable during the welding process, and high-quality welding is easier to achieve and has high repeatability.

[0083] 8. The welding process of the present invention is highly controllable, and the welding device used involves many parameters, and precise control of the welding process can be achieved through the combination of different parameters; at the same time, the welding device includes a temperature and force monitoring and acquisition device, which is convenient for regulating the relationship between the temperature field and the welding force during the welding process, controlling the key parameters of the welding process, and achieving high-quality interface connection.

[0084] 9. The thermal distribution during the welding process of the present invention is uniform. The hollow circular rotating body welding tool designed and used is selected based on the overlap area and overlap size during the welding process, which can ensure that the working conditions of the area to be welded are consistent during the welding process. The thermal conditions of the area to be welded are more uniformly distributed in space, and the molding quality is higher and more uniform. It is suitable for metal / polymer connection of complex rotating body structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0085] Figure 1 Schematic diagram of the hollow circular rotating body welding tool of the present invention, which is one of the various structures of welding tools applicable to the method of the present invention;

[0086] Figure 2 It is a schematic diagram of a device of a welding tool and a welding method for friction lap ring welding of a metal / polymer component of a rotating body structure according to the present invention;

[0087] Figure 3 A schematic diagram of one of the structures of a rotating metal part suitable for the method of the present invention;

[0088] Figure 4 is a schematic diagram of one of the annular polymer structures suitable for the method of the present invention;

[0089] Figure 5 is a schematic diagram of one of the clamping tool structures applicable to the method of the present invention;

[0090] Figure 6 A microscopic representation of the connection surface of a metal / polymer valve component of a preferred embodiment of the present invention;

[0091] Figure 7 A graph showing the temperature monitoring data of the welding process according to a preferred embodiment of the present invention;

[0092] Figure 8 A microscopic representation of the connection surface of a metal / polymer valve component of a poor embodiment of the present invention;

[0093] Fig. 9 A microscopic representation of the connection surface of a metal / polymer valve component of another preferred embodiment of the present invention;

[0094] Fig.10 Schematic diagram of the welding tool used in Comparative Example 1, which is one of the commonly used welding tool structures in the flat plate welding method;

[0095] Fig.11 This is a microscopic characterization image of the connection surface of the metal / polymer valve component of Comparative Example 1;

[0096] In the figure: 1- welding tool, 11- annular friction part, 12- supporting heat dissipation part, 13- mounting part, 14- friction part, 2- clamping tool, 3- workbench, 4- rotating metal part, 5- rotating polymer part, 6- thermocouple for temperature measurement, 7- bolt for fixing the clamping tool, a- rotation direction and downward pressing direction of the welding tool. DETAILED DESCRIPTION

[0097] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0098] A welding tool, such as Figure 1 As shown, it includes an annular friction portion 11, a supporting heat dissipation portion 12 and a mounting portion 13 which are arranged in sequence from bottom to top.

[0099] The welding tool can be used for friction lap ring welding of rotating structure metal / polymer components. The annular friction part 11 can generate heat by friction with the rotating metal part 4 in the rotating structure metal / polymer component. The supporting and heat dissipating part 12 can be used for supporting and dissipating the annular friction part 11. The mounting part 13 is used to connect the welding tool to the welding machine (equipment).

[0100] A welding system such as Figure 2 As shown, it includes the aforementioned rotating body welding tool 1, as well as a clamping tool 2, a workbench 3, a welding device (with a force sensor), a heating device, a thermocouple and a temperature measuring device, and a force sensor and a force acquisition device.

[0101] The welding tool 1 is designed specifically according to actual needs. The part (annular friction part 11) where the welding tool for the rotating body structure metal / polymer component generates heat by friction with the friction surface of the metal part is preferably in a circular shape, and the shape and structure of the part of the welding tool 1 used for frictional heat generation can be designed to regulate the generation and distribution of heat during the welding process; the shape and structure design of the part of the welding tool 1 used for frictional heat generation includes but is not limited to patterns, grooves, etc. The size of the specifically designed welding tool 1 can be optimized and adjusted according to the size of the rotating body metal / polymer component to be welded and the actual interface bonding requirements, so as to meet the uniform distribution of thermal conditions at the welding interface and achieve high-quality connection as a preferred method.

[0102] As a preferred technical solution, the welding tool 1 designed specifically is a hollow annular rotating body, and the structural dimensions of the friction ring (annular friction part 11) used for friction heat generation are related to the actual connection surface dimensions of the valve structure to be welded and the structural shape of the metal parts to be connected; the outer diameter of the friction ring is between 30mm and 150mm, the inner diameter of the friction ring is between 20mm and 130mm, and the thickness of the friction ring is between 2mm and 15mm. Its longitudinal structure can be divided into 3 to 5 sections, and the length of each section is selected between 10mm and 100mm according to actual needs, and the diameter of each section is selected between 15mm and 50mm according to actual needs.

[0103] As a preferred technical solution, each section of the specifically designed rotary welding tool 1 can be selectively processed with patterns or structures to increase the heat dissipation area, and the shape, size and number of the patterns or structures are not limited.

[0104] A welding method for friction lap ring welding of a metal / polymer component of a rotating body structure comprises the following steps:

[0105] (1) embedding a rotational body polymer into a rotational body groove of a metal part having a rotational body structure, so that the polymer is in close contact with the groove connection surface of the metal part;

[0106] (2) Fix the rotating metal / polymer components with fixed position relationship on the workbench using corresponding clamping devices;

[0107] (3) Use a heating device to preheat the area near the surface of the metal / polymer component to be connected to soften the polymer material. The preheating temperature range is 50°C to 300°C.

[0108] (4) The specially designed hollow annular rotating welding tool rotates and presses down the upper surface of the metal part (i.e., the friction surface). The welding tool and the upper surface of the metal part generate heat through friction, and the heat is transferred to the metal / polymer connection interface by relying on the thermal conductivity of the metal, so that the polymer material melts and forms an interface bond under the action of the welding force.

[0109] As a preferred technical solution, step (4) controls the rotation speed of the welding tool to be between 200rpm and 2000rpm, the pressing speed to be between 0.1mm / min and 10mm / min, and controls the interface temperature of the connecting surface of the polymer and the metal groove to be 180℃ to 450℃ during the welding process, so that the polymer and the connecting surface of the metal groove are effectively connected.

[0110] As a preferred technical solution, the surface of the metal groove to be connected is surface treated to prepare a surface active rough layer, which is beneficial to improving the bonding quality of the metal / polymer connection interface.

[0111] Furthermore, the method for treating the metal surface includes but is not limited to anodizing, sandblasting, plasma treatment, laser etching, etc.

[0112] As a preferred technical solution, the polymer / metal structure of the rotating body in step (1) includes circular structures such as cylindrical, annular, cylindrical, and complex structures involving circular or quasi-circular connecting surfaces.

[0113] As a preferred technical solution, the surface to be connected of the rotating metal / polymer component is not limited to a plane, but can be a curved surface of any shape and structure.

[0114] As a preferred technical solution, the pressing amount of the rotary welding tool is related to the thickness d of the metal part to be welded, and the pressing amount is selected in the range of 0.05×d to 0.3×d.

[0115] As a preferred technical solution, the rotation speed and pressing speed of the rotary welding tool are selected according to the heat required for the welding process. The rotation speed of the rotary welding tool described in step (4) is preferably between 400rpm and 1000rpm, the pressing speed is preferably between 0.8mm / min and 4mm / min, and the welding time is controlled between 5s and 60s.

[0116] As a preferred technical solution, the axial force during welding can be measured using the equipment's own force sensor, or an external force sensor, and the welding force can be monitored and collected using a working computer.

[0117] As a preferred technical solution, the metal part is machined to produce a plurality of square or circular tunnels for thermocouples to be inserted into to measure the temperature field during the welding process.

[0118] Furthermore, the rotating metal / polymer components to be connected are fixed on the workbench by clamping tools after assembly, and the thermocouple is connected near the metal / polymer connection interface through a square or circular tunnel, and the temperature measurement point is preferably on the metal side close to the interface position; the thermocouple and temperature measuring device include but are not limited to flexible thermocouples, temperature collectors and working computers.

[0119] Furthermore, the clamping tool is an embedded structure suitable for a circular rotating body structure. The clamping tool is fixed to the workbench by bolts, and can provide sufficient clamping force for the metal / polymer components to be welded; the workbench is a square metal thick plate, and its strength and rigidity should meet the welding requirements. The workbench has a hole structure for bolt connection.

[0120] Further preferably, the clamping tool includes a device for fixing the position of the structure to be welded in the working plane and a device for limiting the position of the structure to be welded axially, thereby ensuring that the structure to be welded does not move or deflect in the direction of the working plane, while allowing the structure to be welded to have freedom of longitudinal movement during the welding process.

[0121] As a preferred technical solution, in the description of step (3) of preheating the valve structure to be welded, the preheating device includes but is not limited to a hot air gun, a heating plate, etc. The upper limit of the preheating temperature is the melting temperature of the polymer material used for welding, and the preheating time is preferably selected between 30s and 120s.

[0122] The following describes it in detail with reference to specific embodiments.

[0123] Unless otherwise specified, the reagents, methods, instruments and equipment used in the present invention are conventional reagents, methods, instruments and equipment in the art. Unless otherwise specified, the reagents and materials used in the following examples are commercially available.

[0124] Example 1

[0125] Before the welding experiment, the aluminum alloy valve part (rotating body metal part 4) was anodized using a sulfuric acid solution with a volume fraction of 20% for 2 hours in a constant current mode with a current of 5 A. An active rough layer was formed on the surface of the aluminum alloy valve to be welded by oxidation, which was beneficial to the interface bonding between the aluminum alloy and the fluorocarbon polymer.

[0126] A fluorocarbon polymer ring (rotating polymer part 5) with a thickness of 5 mm, a height of 15 mm, and inner and outer diameters of 55 mm and 65 mm respectively is embedded in the Figure 3 In the groove of the valve part shown, the groove has a depth of 5 mm and a width of 5 mm, and the inner and outer diameters are the same as those of the above-mentioned polymer ring, ensuring that the two can achieve good fit.

[0127] like Figure 2 A thermocouple slot for temperature measurement in the centripetal direction is provided on the outside of the valve part. The length of the thermocouple slot is such that the temperature measurement point of the thermocouple (thermocouple 6 for temperature measurement) can be located at the radial center of the metal / polymer interface. The cross-sectional size of the thermocouple slot is 1mm*1.5mm. The thermocouple slot is provided inside the valve part on the metal side of the interface, and the longitudinal distance from the interface is 0.5mm.

[0128] The rotation direction and downward pressure direction of the welding tool during welding are as follows: Figure 2 As shown, the welding force is collected using the sensor provided by the welding equipment, and the welding force is fed back to the welding machine through the welding tool.

[0129] like Figure 2 , fix the fixture required for welding (clamping tool 2) on the workbench 3 by bolts (bolts 7 for fixing the clamping tool), and place the above-mentioned assembled valve parts and polymer ring in a fixed position in the welding fixture.

[0130] Clamps used to fix welding parts such as Figure 5 As shown, the outer diameter of the pit is 65mm, the depth of the pit is 5mm, and the width of the bearing area at the bottom of the pit is 10mm, which ensures that the polymer ring can be fixed in the fixture without movement and deflection during welding, and at the same time ensures that the valve parts do not collide with the fixture during welding.

[0131] The upper clamping tool is used together with the clamping tool 2 to clamp the metal part (rotating metal part 4) to prevent the metal part from rotating or shifting due to the friction between the welding tool 1 and the metal part at the beginning of welding. At the same time, this part of the clamping tool must act on the appropriate position of the top surface of the metal part to avoid hindering the rotation and downward pressure of the welding tool 1. This part of the clamping tool can play the above role, and the shape and size are suitable for the implementation of the welding process, and there is no specific restriction, so it is not marked in the drawings.

[0132] Welding tools 1 Figure 1As shown, its structure is a rotating body, and the area used for friction with valve parts is annular, the thickness of the ring is 5mm, and the inner and outer diameters of the ring are 40mm and 50mm respectively. The height of the annular area used for friction is 10mm. The longitudinal structure of the welding tool 1 is divided into 3 sections, from bottom to top, there are annular friction parts 11 for friction heat generation, support and heat dissipation parts 12 for support and heat dissipation, and installation parts 13 for installation with welding machines. The length of the part used for support and heat dissipation is 30mm, the diameter is 40mm, and the length of the part used for installation with the welding machine is 35mm, the diameter is 20mm. The plane used for friction at the bottom of the welding tool used in this embodiment has no structural design, and the part used for support and heat dissipation is provided with 3 circumferential semicircular grooves, the radius of the groove is 2mm, and the center distance between the grooves is 6mm, which is used to increase the heat dissipation area.

[0133] Before welding, use a hot air gun to evenly preheat the area around the valve parts. The preheating time is 60 seconds and the preheating temperature is as follows: Figure 7 As shown, it is about 55℃. After preheating, start the welding machine. Figure 1 The welding tool 1 shown is pressed down while rotating. Here, the rotation speed of the welding tool 1 is 500 rpm, the pressing speed is 2 mm / s, and the pressing amount is 1 mm. When the interface temperature drops to close to room temperature, the welding tool 1 is lifted up and the welding process is completed.

[0134] The successfully welded parts are processed by milling machine in the interface bonding area to produce samples for characterization. Figure 6 This is the interface scanning electron microscope image under the welding parameters. During the welding process, due to the high interface temperature, under the action of welding force, the metal surface and the molten polymer at the interface are tightly combined to form an effective connection.

[0135] In the present invention, a thermocouple and a force sensor of the welding equipment are used to monitor and collect the interface temperature and welding force during the welding process. When the welding is completed, the interface temperature is about 250° C., and the average welding force during the welding process is about 4 kN.

[0136] Example 2

[0137] The same welding device, temperature measuring device, etc. are installed with the metal valve parts and polymer ring in the same manner as in Example 1.

[0138] Use a hot air gun to preheat the valve parts to be welded for 60s. After preheating, select a welding speed of 500rpm, a pressing speed of 5mm / s, and a pressing amount of 1mm. Wait for the interface temperature to drop to near room temperature and then lift the welding tool. The welding process is completed.

[0139] The welding tools used in the welding process are the same as those in Example 1.

[0140] In this embodiment, the maximum interface temperature during the welding process was measured to be 190° C., and the average welding force was 7 kN.

[0141] Figure 8 This is a scanning electron microscope image of the interface in this embodiment. Due to the high pressing speed during welding, the welding force is significantly improved, but due to the short welding time, the welding is stopped before the interface temperature rises to a high enough level. Therefore, the polymer is not fully heated and melted, resulting in poor interface bonding.

[0142] Example 3

[0143] The same welding device, temperature measuring device, etc. are installed with the metal valve parts and polymer ring in the same manner as in Example 1.

[0144] Select a welding speed of 400rpm, a pressing speed of 0.9mm / s, and a pressing amount of 0.6mm. Wait for the interface temperature to drop to close to room temperature, then lift the welding tool and the welding process is completed.

[0145] The structure of the welding tool used in the welding process is a rotating body, and the area used for friction with the valve parts is annular, the thickness of the ring is 5mm, and the inner and outer diameters of the ring are 30mm and 40mm respectively. The height of the annular area used for friction is 10mm. The longitudinal structure of the welding tool is divided into 3 sections, from bottom to top, for friction heat generation, for support and heat dissipation, and for installation with the welding machine. The length of the part used for support and heat dissipation is 30mm and the diameter is 40mm, and the length of the part used for installation with the welding machine is 35mm and the diameter is 20mm. The plane used for friction at the bottom of the welding tool used in this embodiment has no structural design, and the part used for support and heat dissipation is provided with 3 circumferential semicircular grooves, the radius of the groove is 2mm, and the center distance between the grooves is 6mm, which is used to increase the heat dissipation area.

[0146] In this embodiment, the maximum interface temperature during welding is measured to be 300°C, and the average welding force is 3.8 kN. The interface bonding condition under this welding parameter is characterized by: Fig. 9 . A good bond is formed at the interface.

[0147] By adjusting the size of the welding tool, the interface bonding area is transferred to the inner side of the groove of the metal part, which shows that the directional control of the interface bonding area can be achieved by optimizing and adjusting the welding tool.

[0148] Comparative Example 1

[0149] The same metal valve parts, polymer rings, temperature measuring devices and other required components are installed in the same manner as in Example 1.

[0150] Use as Fig.10The welding tool 1 shown is used for welding. The welding tool 1 is a rotating body, and the part used for frictional heat generation with the metal part is a cylinder with a diameter of 10 mm (friction part 14), and the height of the part used for frictional heat generation is 10 mm. The structure and size of the remaining parts of the welding tool 1 are the same as those of the corresponding parts of the welding tool 1 in Example 1.

[0151] No preheating was performed before welding. During the initial welding process, the welding speed was selected to be 555 rpm, the pressing speed was 2.4 mm / s, and the pressing amount was 1.2 mm. After the pressing process was completed, the welding speed was selected to be 150 mm / min, and the welding tool was moved along a circular path with a diameter of 50 mm, which was coaxial with the outer contour of the metal part. When the welding tool moved a full circle, it stopped rotating and lifted the welding tool to complete the welding.

[0152] In this comparative example, the interface temperature during welding was measured to be between 270°C and 410°C, and the interface temperature at different positions was significantly different. At the same time, due to the uneven spatial distribution of the downward pressure applied by the welding tool on the metal parts during welding, the parts deflected to a certain extent. In addition, during the movement of the welding tool, the interface on the side opposite to the welding tool that has completed the welding process will be damaged due to the above-mentioned part deflection.

[0153] Fig.11 This is a characterization diagram of the interface bonding condition of a certain area of ​​the welded part described in this comparative example.

[0154] Therefore, the welding effect of the metal-polymer composite structure of the rotating body structure using the commonly used cylindrical welding tool is poor, and the interface bonding condition is far inferior to the new welding tool described in the present invention.

[0155] The above embodiments describe in detail the specific implementation steps and implementation methods of the present invention. It should be noted that the present invention does not limit the specific shape and size of metal valve parts, does not limit the surface treatment method for the surfaces of metal parts to be connected, does not limit the related design and use of clamping tools and clamping forms, does not limit the specific shape and size of welding tools, and does not limit the parameter selection and process monitoring during welding. Those skilled in the art can make many changes and modifications according to the present invention. Therefore, all technical solutions obtained by those skilled in the art through logical analysis, reasoning or experiments according to the contents involved in the present invention are within the scope of protection determined by the claims.

[0156] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A welding tool for friction lap welding of metal / polymer components of a rotating structure, characterized in that: The invention comprises an annular friction part (11) for generating heat by friction with a rotating metal part in a rotating structure metal / polymer assembly, a supporting heat dissipation part (12) for supporting and dissipating heat, and a mounting part (13) for connecting with a welding machine, which are arranged in sequence.

2. The welding tool for friction lap welding of metal / polymer components of a rotating structure according to claim 1 is characterized in that: The annular friction part (11) is a hollow annular rotating body with an outer diameter between 30 mm and 150 mm, an inner diameter between 20 mm and 130 mm, and a thickness between 2 mm and 15 mm.

3. The welding tool for friction lap welding of metal / polymer components of a rotating structure according to claim 1, characterized in that: The rotator structure metal / polymer component comprises a rotator metal part and a rotator polymer part. The rotator metal part is provided with a rotator groove for installing the rotator polymer part.

4. A welding system for friction lap ring welding of metal / polymer components of a rotating structure, characterized in that: A welding tool (1) comprising the welding tool (1) according to any one of claims 1 to 3, further comprising a clamping tool (2), a workbench (3), a temperature measuring device and a force acquisition device; The clamping tool (2) is used to fix the metal / polymer component of the rotating body structure on the workbench (3), the temperature measuring device includes a thermocouple for collecting the temperature of the metal / polymer surface area to be connected, and the force collection device includes a force sensor for collecting the axial welding pressure.

5. The welding system for friction lap ring welding of metal / polymer components of a rotating structure according to claim 4 is characterized in that: The invention also comprises a heating device for preheating the metal / polymer surface area to be connected.

6. A welding method for friction lap ring welding of metal / polymer components of a rotating structure, characterized in that: The method is carried out using the welding system according to any one of claims 4 to 5, comprising the following steps: S1: embedding the rotating polymer part into the rotating groove of the rotating metal part, so that the rotating polymer part is in close contact with the surface to be connected of the rotating groove; S2: Fixing the metal / polymer component of the rotating structure with a fixed position relationship on the workbench (3) using a clamping tool (2); S3: The welding tool (1) is rotated and pressed down on the upper surface of the rotating metal part. The welding tool (1) and the surface of the rotating metal part generate heat through friction, so that the rotating polymer part and the rotating groove surface to be connected are effectively connected.

7. The welding method for friction lap ring welding of metal / polymer components of a rotating structure according to claim 6, characterized in that: In step S3, the rotation speed of the welding tool (1) is 200 rpm to 2000 rpm, the pressing speed is between 0.1 mm / min and 10 mm / min, and the interface temperature between the rotating polymer part and the rotating groove to be connected during the welding process is controlled to be 180° C. to 450° C.

8. The welding method for friction lap ring welding of metal / polymer components of a rotating structure according to claim 6, characterized in that: In step S3, the pressing amount of the welding tool (1) is related to the thickness d of the rotating metal part to be welded, and the range of the pressing amount is between 0.05×d and 0.3×d.

9. The welding method for friction lap ring welding of metal / polymer components of a rotating structure according to claim 6, characterized in that: Step S1: the surface of the rotating body groove to be connected is prepared with a surface active rough layer through surface treatment; The surface treatment methods include anodizing, sandblasting, plasma treatment, and laser etching.

10. The welding method for friction lap ring welding of metal / polymer components of a rotating structure according to claim 6, characterized in that: A preheating step is provided between steps S2 and S3, wherein a heating device is used to preheat the surface area of ​​the metal / polymer component of the rotating body structure to be connected to soften the polymer material, and the preheating temperature range is 50° C. to 300° C.; The rotating metal part is provided with a tunnel for the thermocouple to pass through.

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