A floating adjustable positioning head assembly for aviation heat exchanger welding fixture

Abstract

The present invention belongs to the field of mechanics and relates to a floating adjustable positioning head assembly for an aviation heat exchanger welding fixture; the assembly comprises a positioning shaft, a screw plug, a taper sleeve, a pin, a sleeve, a connecting rod, and a wrench. The positioning shaft is a hollow shaft, the operating lever of the wrench is arranged inside the positioning shaft, the tapered surface of the taper sleeve is arranged at one end of the positioning shaft and is positioned by the tapered surface, the screw plug is a hollow external thread structure, arranged inside the internal thread of the positioning shaft by threading, the screw plug clamps the taper sleeve through the closing end, the connecting rod is transitionally fitted in the end hole of the taper sleeve and is fixedly connected by the pin, the sleeve is an internal thread structure, arranged outside the connecting rod, and is limited by the step of the connecting rod to tighten the nozzle; the wrench is rotated inside the positioning shaft and drives the taper sleeve, which cooperates with the tapered surface of the positioning shaft to tighten and loosen, and drives the connecting rod, sleeve, and nozzle to be fixed. The present invention can unload the force between the product and the fixture in multiple directions, greatly reducing damage to the product.

Description

Technical Field

[0001] The present invention belongs to the field of machinery and relates to a positioning head on a product welding fixture, which is used for accurately and conveniently positioning and fastening nozzle components during welding of aviation heat exchangers, and can easily and conveniently disassemble the product after welding is completed. Background Art

[0002] Welding is a commonly used and reliable joining process, widely used in the research and production of various products across many industries. Metal welding involves processes such as heating, melting, solidification, and cooling. Therefore, during and after the welding process, the related components will undergo significant deformation, which will significantly change the relevant dimensions and shapes of the products. When high requirements are placed on the size and shape of the product, welding fixtures are usually used to offset excessive deformation to ensure product quality and technical requirements. When using fixtures for welding, large forces will be generated between the components of the product after welding, and between the product and the fixture due to welding deformation. Some products with certain structures make it very difficult to disassemble and separate the product and the welding fixture, such as most aviation heat exchangers.

[0003] Aviation heat exchangers are typical welded structure products. It is very difficult to disassemble the products after welding, which brings great adverse effects. It is very necessary to solve this kind of problem.

[0004] This type of product has a complex overall structure and shape, requiring numerous channel interfaces, various mounting and positioning accessories, and high overall tolerance requirements. To ensure product quality, high-precision and high-rigidity welding fixtures are typically used during the assembly and welding of heat exchangers. The connections between the fixtures and related components must be precise and reliable to ensure assembly accuracy, resist welding deformation, and ultimately meet product tolerance requirements. After the heat exchanger's assembly and final production, the high forces between the product and the fixture caused by welding deformation make it very difficult to remove the product from the fixture, often resulting in deformation or damage to the product. Violent removal can even lead to deformation or damage to the fixture.

[0005] Most of these products form a closed structure after welding, or form a closed structure with the fixture. After welding and production, the positioning head is sealed in the cavity, which makes it difficult to take measures to unload the relevant forces. At the same time, this is also a common problem that needs to be overcome in similar processes.

[0006] The primary connection between the fixture and the heat exchanger's components is the locating head assembly, a core component of the fixture and the key to resolving disassembly difficulties. The difficulty in disassembling these products after welding stems from two main factors: first, ensuring easy and convenient disassembly while ensuring a precise, reliable connection and sufficient rigidity; second, ensuring repeatability after repositioning to meet the consistency requirements of the product and fixture; and third, due to the enclosed structure, in some cases, the locating head must be removed externally.

[0007] At present, the traditional threaded nozzles are Figure 1 As shown, for welding this type of interface, the current positioning head assembly can only slide axially. That is, the positioning shaft 6 slides within the positioning sleeve 10. Before welding, the flange of the positioning shaft 6 is in contact with the positioning sleeve 10 to determine the axial position. After welding, the positioning sleeve assembly cannot move, and the force between the product and the fixture cannot be relieved, making it difficult to disassemble the product. The sleeve 2 of the current fixture is made of copper, which reduces the friction coefficient, but the difficulty in disassembly still often causes damage to the product and the fixture.

[0008] Another approach used by domestic and international competitors to address similar issues is to separate assembly and welding. This involves fitting and spot-welding components on a fixture, and then welding outside the fixture. This approach doesn't constrain deformation during welding, and primarily controls some of the factors that influence it. This results in relatively large deformation in the final product. This process is unsuitable for complex and demanding products, and therefore, the fixture-related issues need to be addressed urgently. Summary of the Invention

[0009] Purpose of the present invention:

[0010] A floating universal positioning head assembly for aviation heat exchanger welding fixtures has been designed. This core component enables precise positioning of threaded nozzles and end caps in heat exchanger joint assemblies. It also addresses the significant stress generated by weld shrinkage after welding, which can lead to high contact forces between the product and the fixture, making disassembly difficult. It can also be used with a variety of other nozzle types.

[0011] The technical solution of the present invention:

[0012] A floating adjustable positioning head assembly for an aviation heat exchanger welding fixture comprises a positioning shaft, a screw plug, a tapered sleeve, a pin, a sleeve, a connecting rod and a wrench. The positioning shaft is a hollow shaft, the operating rod of the wrench is arranged inside the positioning shaft, the tapered surface of the tapered sleeve is arranged at one end of the positioning shaft and is positioned by the tapered surface, the screw plug is a hollow external thread structure, which is arranged in the internal thread of the positioning shaft by thread fitting, the screw plug clamps the tapered sleeve by closing, the connecting rod transition fits in the end hole of the tapered sleeve and is fixedly connected by a pin, the sleeve is an internal thread structure, which is arranged on the outside of the connecting rod and is limited by the step of the connecting rod for tightening the nozzle; the wrench is rotated in the positioning shaft and drives the tapered sleeve to tighten and loosen with the tapered surface of the positioning shaft, and drives the connecting rod, sleeve and nozzle to be fixed.

[0013] Furthermore, the positioning shaft is also provided with an axial limiting flange for positioning with the positioning sleeve of the fixture and is integrally formed with the positioning shaft.

[0014] Furthermore, a tapered hole is provided at one end of the positioning shaft for positioning the tapered sleeve. The matching taper can be adjusted according to specific use requirements.

[0015] Furthermore, the inner hole of the positioning shaft is provided with a thread for the rotational movement of the screw plug.

[0016] Furthermore, the positioning shaft is tempered to HRC33~38.

[0017] Furthermore, the screw plug is a hollow external thread structure.

[0018] Furthermore, one end of the inner hole of the screw plug is set to an inner hexagonal structure, and the end of the operating rod of the wrench is a hexagonal structure, which matches the inner hexagonal screw plug.

[0019] Furthermore, the other end of the inner hole of the screw plug is set as a circular hole with an outward convex step, which is clamped in the cone sleeve after closing.

[0020] Furthermore, the plug is tempered to HRC33~38.

[0021] Furthermore, the tapered sleeve is a tapered shank structure with a tail shank, one end of which is provided with a hole for transitional connection with the connecting rod, and the other end of which is provided with a flange for connection with the screw plug.

[0022] Furthermore, the connecting rod is a shaft with a flange, which is used to position the nozzle.

[0023] Furthermore, the cone sleeve and the connecting rod may be an integral structure.

[0024] Furthermore, the end of the connecting rod of the integral structure is provided with a thread for installing a positioning flange and is tightened with a gasket and a nut, and can be used for the installation and positioning of various forms of nozzles.

[0025] Furthermore, the outer cone of the cone sleeve can be changed into an inner cone, and the inner cone of the corresponding positioning shaft can be changed into an outer cone, and then pressed tightly with an outer sleeve.

[0026] Advantages of the present invention:

[0027] 1. The precision and reliability of the taper fit in orientation and positioning are utilized to achieve the precision and rigidity requirements of the positioning head during operation. On this basis, the multiple degrees of freedom in the loosened state are utilized to achieve the relaxation of the multiple degrees of freedom of the positioning head when loosened, which well meets the needs of welding fixtures.

[0028] 2. Threaded connections provide a certain degree of freedom while ensuring the required connection force. The hollow screw plug and the tapered sleeve close the connection to meet the connection requirements under structural constraints.

[0029] 3. Avoid disassembling the product and fixture under large contact force, so as to protect the product well.

[0030] The positioning head assembly of the present invention overcomes the limitations of the product's closed structure on the operation of the clamp. By operating the screw plug of the positioning head, the connecting rod can be placed in a floating state, and the force between the product and the clamp can be unloaded in multiple directions, thereby making it easier to disassemble the product and greatly reducing damage to the product.

[0031] 4. Better effect and more convenient to use.

[0032] The positioning head assembly of the present invention overcomes the limitations imposed on fixture operation by the product's enclosed structure, achieving multiple functions, including radial and axial positioning and tightening, using a single set of parts. The screw plug 5 effectively connects the conical connecting rod and the positioning shaft. While it can quickly and accurately position the product's joint assembly like a conventional positioning head, it can also quickly and conveniently relieve the forces between the product and the fixture, allowing for easy disassembly of the welded product and fixture. This solves the difficulty of disassembling conventional positioning heads and offers greater precision and reliability.

[0033] Simply loosen the screw plug from the outside of the closed structure formed by the fixture and the product with a wrench to float the connecting rod, allowing it to be adjusted in multiple directions, completely unloading the forces between the product and the fixture. This effectively unloads the forces and is easy to operate.

[0034] Compared to existing positioning head assemblies, disassembly can be done by loosening the taper sleeve and positioning shaft, leaving the connecting rod in an omnidirectionally free state, thereby unloading the forces acting between the product and the fixture. At this point, loosening the sleeve to loosen the connection between the fixture and the nozzle is much easier, and the product will not be damaged by the high forces.

[0035] By using a wrench to tighten the screw plug from the outside of the closed structure formed by the fixture and the product, the conical surface of the connecting rod and the positioning shaft can be closely matched, so that the positioning head assembly can be in working condition, with reliable connection and convenient operation.

[0036] The positioning head assembly of the present invention can be used interchangeably with similar positioning heads used in current fixtures, greatly reducing the investment cost of the fixture.

[0037] 6. The locating head structure of this invention offers significant scalability. It can be modified and applied to other types of fixtures or connections, addressing product structural limitations and the impact of process stress on fixture assembly and disassembly. For example, improvements to the connecting rod structure can be applied to the welding of clamp-type nozzles; further improvements can be applied to the welding of bracket-type parts with hole positioning. Furthermore, the use of an externally mounted conical surface can meet the needs of a variety of scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a structural schematic diagram showing a positioning head of an existing threaded nozzle;

[0039] Figure 2 1 is a schematic diagram showing the structure of a positioning head capable of floating adjustment according to the present invention;

[0040] Figure 3 1 is a schematic structural diagram of an improved positioning head of the connecting rod of the present invention;

[0041] Figure 4 is a cross-sectional view showing a screw plug of the present invention;

[0042] Figure 5 1 is a top view of the screw plug of the present invention;

[0043] Figure 6 1 is a schematic diagram showing an improved connecting rod structure of the present invention;

[0044] Figure 7 1 is a schematic structural diagram of a positioning head of an improved connecting rod according to the present invention;

[0045] Figure 8 1 is a schematic diagram showing the structure of the positioning head with external conical surface fit according to the present invention;

[0046] Figure 9 The present invention is a structural schematic diagram showing a positioning head of an existing flange nozzle.

[0047] Among them, connecting rod 1, sleeve 2, pin 3, tapered sleeve 4, screw plug 5, positioning shaft 6, wrench 7, nozzle 8, head 9, positioning sleeve 10, outer sleeve 11, nut 12, gasket 13, positioning flange 14. DETAILED DESCRIPTION

[0048] The specific implementation of the present invention will be further described below with reference to the accompanying drawings.

[0049] The present invention provides a new positioning head assembly on an aviation heat exchanger welding fixture, which can well meet the comprehensive requirements of accurate and reliable positioning before welding, deformation resistance during welding, and easy and quick separation of the product and the fixture after welding, which is conducive to improving production efficiency and product quality.

[0050] The positioning head assembly is the core component of the heat exchanger welding fixture. It is used to accurately locate and tighten the nozzle-type interfaces of the heat exchanger. It can achieve axial and radial positioning and tightening of parts such as nozzles, resist welding deformation during the welding process, and ensure that the size and form and position tolerances of the relevant interfaces after welding meet the product design requirements.

[0051] The technology of heat exchanger welding fixtures has gone through three generations: fixed, axially movable, and multi-directionally adjustable. These developments are mainly related to the development of positioning heads.

[0052] Traditional fixture designs have no moving parts. All components, including the positioning head, are fixedly connected and cannot be moved or adjusted. Therefore, after the product is welded, the fixture must be disassembled to remove the product. This fixture structure is simple and offers excellent precision and rigidity. However, it has two major drawbacks: disassembly and assembly require considerable time, resulting in low overall production efficiency; and restoring the fixture can introduce dimensional deviations, affecting the product's dimensional accuracy and even causing product failure.

[0053] In the industry, the more common positioning head assembly can slide axially, see Figure 1 The biggest drawback of this type of fixture is the difficulty in removing the product. The enormous forces between the product and the fixture caused by welding deformation create significant resistance to movement of the shaft within the locating sleeve and the locating head's movement from the product interface, making product removal difficult. This not only severely impacts production efficiency, but can also damage the fixture's precision and even the product due to the forceful movement of the locating head. This has severely impacted current scientific research and production.

[0054] The forces that make it difficult to move the positioning head assembly come from the deformation of the welded parts. These deformations are multi-directional, generating multi-directional forces. The second-generation fixture can only move axially and can only relieve axial forces, but not radial forces. Therefore, disassembly of the fixture is still difficult.

[0055] From the above analysis, it can be seen that the key to solving this problem is to be able to unload the radial force. This is one of the key technical points in the current welding and assembly of heat exchangers and related sheet metal products, and also one of the main areas for improving welding fixtures.

[0056] In order to realize the multi-directional adjustment of the positioning head, the present invention specifically designs the first embodiment:

[0057] like Figure 2 The figure shows a schematic diagram of the structure of a threaded nozzle positioning head.

[0058] The threaded connection type positioning head structure includes a positioning shaft 6, a screw plug 5, a tapered sleeve 4, a pin 3, a sleeve 2, a connecting rod 1, and a wrench 7. The positioning shaft 6 is a hollow shaft, and the operating rod of the wrench 7 is arranged inside the positioning shaft 6. The tapered sleeve 4 is arranged on the conical surface at one end of the positioning shaft 6 and is multi-directionally positioned through the tapered surface. The screw plug 5 is arranged inside the positioning shaft 6, cooperates with the positioning shaft through a thread, clamps the tapered sleeve 4 through the closing end, and rotates inside the positioning shaft 6 and drives the tapered sleeve 4 through the rotation of the wrench 7. The connecting rod 1 is transitionally fitted in the end hole of the tapered sleeve 4 and is fixedly connected by the pin 3. The sleeve 2 is an internal thread structure for tightening the nozzle 8, which is arranged on the outside of the connecting rod 1 and is limited by the step of the connecting rod 1.

[0059] like Figure 2 The specific operation of the positioning head assembly of the present invention is as follows:

[0060] In the assembly stage before welding, tighten the screw plug 5 to make the cone sleeve 4 fit tightly with the positioning shaft 6 to achieve accurate radial and axial positioning, and move the positioning head assembly in the positioning sleeve 10 until the step flange of the positioning shaft 6 fits tightly with the positioning sleeve 10 and locks it; Figure 1 , as with the original positioning head, use the internal thread of the sleeve 2 to tighten the nozzle 8, and assemble the various components of the product accordingly.

[0061] During the disassembly stage after welding, first use a wrench 7 to loosen the screw plug 5 to loosen the cone sleeve 4 and the positioning shaft 6; then loosen the sleeve 2 and the nozzle 8 until they are completely disengaged; then pull the positioning head assembly out of the positioning sleeve 10 until it is separated from the product; and remove the product from the fixture.

[0062] By loosening the tapered sleeve 4 and the tapered surface of the positioning shaft 6, the connecting rod 1 can have multiple degrees of freedom in axial, radial and angular directions, thereby removing the multi-directional force between the product and the fixture formed by welding deformation, making it much easier to loosen the positioning head and the product nozzle.

[0063] like Figure 2 The positioning head assembly of the present invention is improved by improving the original connection between the connecting rod 1 and the positioning shaft 6. The ordinary fixed type of equal diameter shaft hole with pin fixation is improved to a movable type with conical surface fit by adding a tapered sleeve 4, and is fixed and loosened with a screw plug 5. It can achieve multi-directional adjustment and can completely unload the force between the product nozzle 8 and the positioning head assembly. Therefore, it is very easy to remove the product from the fixture, and the product and fixture will not be damaged due to the large force and removal force. Compared with Figure 1 The fixed positioning head shown retains its advantages of precision and good rigidity and inherits the basic form of axial sliding and positioning in the positioning sleeve 10 .

[0064] During the specific implementation process, the angle of the tapered sleeve 4 and the tapered surface of the positioning shaft 6 can be designed according to actual needs to meet the proportional requirements of axial and radial movement; it can also be used to meet the coordination requirements of axial tightening force and radial bearing capacity.

[0065] The hexagonal inner hole of the hollow plug 5 allows for easy operation by using a wrench 7 through the hollow interior of the positioning shaft 6. The tapered sleeve 4 is clamped by the closing end, resulting in a simple structure and a reliable connection. The adjustment of the plug 5 and positioning shaft 6 enhances the component's load-bearing capacity and increases its service life.

[0066] The positioning head assembly of the present invention can be standardized. According to different requirements such as product structure and size, the threads and hexagonal socket of the core component of the positioning head assembly of the present invention, as well as the threads of the matching positioning shaft 6, are standardized and adopt the standard recommended dimensions for easy processing and universal use.

[0067] like Figure 3 The figure shows a schematic diagram of the structure of an improved floating positioning head assembly. The improved positioning head assembly structure includes a positioning shaft 6, a screw plug 5, a sleeve 2, a connecting rod 1, and a wrench 7. The positioning shaft 6 is a hollow shaft, and the operating rod of the wrench 7 is arranged inside the positioning shaft 6. The connecting rod 1 is arranged at one end of the positioning shaft 6 with a conical surface, and is multi-directionally positioned by the conical surface. Figure 4 、 Figure 5As shown, the screw plug 5 is a hollow external thread structure, which is arranged in the internal thread of the positioning shaft 6. The screw plug 5 clamps the connecting rod 1 through the closing mouth and can be rotated in the positioning shaft 6 by the wrench 7, thereby driving the connecting rod 1 to tighten and loosen the tapered surface of the positioning shaft 6. The sleeve 2 is an internal thread structure, which is arranged on the outside of the connecting rod 1 and is limited by the step of the connecting rod 1 to tighten the nozzle 8. Compared with Figure 2 The positioning head assembly shown here integrates the cone sleeve and connecting rod into a single unit. The connecting rod 1 has fewer parts and a simpler structure. This positioning head is suitable for applications where the structure allows.

[0068] The second embodiment of the present invention:

[0069] like Figure 7 The figure shows a schematic diagram of a positioning head structure without a sleeve 2. The positioning head structure of the hole positioning type connector includes a positioning shaft 6, a plug screw 5, a connecting rod 1 and a wrench 7. The positioning shaft 6 is a hollow structure, and the wrench 7 is arranged inside it. The plug screw 5 is a hollow external thread structure, which is arranged in the internal thread of the positioning shaft 6. The plug screw 5 clamps the connecting rod 1 through the closing end. It can be rotated in the positioning shaft 6 through the wrench 7, and drives the connecting rod 1 to tighten and loosen the conical surface of the positioning shaft 6. The connecting rod 1 is a stepped shaft, and the boss at one end is clamped in the plug screw 5, and the step and shaft at the other end are used to position related product parts.

[0070] like Figure 7 The operation of the positioning head of the hole positioning type connector shown is as follows:

[0071] During the pre-welding assembly stage, tighten the screw plug 5 to drive the connecting rod 1 to be fastened to the positioning shaft 6 through the tapered surface, and move the positioning head assembly in the positioning sleeve 10 until the step of the positioning shaft 6 fits tightly with the positioning sleeve 10 and is locked, thereby achieving accurate radial and axial positioning of the end shaft and step of the connecting rod 1.

[0072] During the disassembly stage after welding, the screw plug 5 is loosened to release the fit between the connecting rod 1 and the positioning shaft 6. The connecting rod 1 can move freely in multiple directions, and the product can be disassembled easily and conveniently.

[0073] like Figure 7 The positioning head of the hole-locating connector shown here utilizes a tapered fit. When tightly fitted, it provides precise and reliable positioning, meeting welding requirements. When loosened, it offers ample adjustment freedom and range for full unloading. The positioning head assembly is simple and reliable, and can be operated from outside the enclosed structure for easy operation.

[0074] Furthermore, if necessary, the end of the shaft at the end of the connecting rod 1 can be processed into a thread, and the relevant parts can be tightened with a nut.

[0075] The third embodiment of the present invention:

[0076] like Figure 6 As shown, it is a schematic diagram of the structure of a flange type nozzle positioning head. The flange type positioning head structure includes a connecting rod 1, a positioning flange 14, a gasket 13, and a nut 12. The connecting rod 1 is a stepped shaft with a flange, one end of which is stuck in the screw plug 5 and the other end is a threaded shaft. The positioning flange 14 is pressed against the flange by the nut 12 and the gasket 13. Figure 2 This operation is used to position and tighten flange type nozzles.

[0077] like Figure 6 The positioning head of the present invention is replaced by Figure 2 The specific operation of the positioning head assembly formed by the middle connecting rod 1, sleeve 2, pin 3, and cone sleeve 4 is as follows:

[0078] During the assembly stage before welding, tighten the screw plug 5 to make the connecting rod 1 fit tightly with the positioning shaft 6 to achieve accurate radial and axial positioning, and move the positioning head assembly in the positioning sleeve 10 until the step of the positioning shaft 6 fits tightly with the positioning sleeve 10 and locks it; then install the nozzle to be welded and tighten it with the corresponding tightening tool.

[0079] During the disassembly stage after welding, first use a wrench 7 to loosen the screw plug 5 to loosen the connecting rod 1 and the positioning shaft 6, thereby releasing the force between the product and the fixture; then loosen the fastening tool of the nozzle to loosen the product and the positioning head; then pull the positioning head assembly out of the positioning sleeve 10 until it is separated from the product; and remove the product from the fixture.

[0080] By loosening the tapered sleeve 4 and the tapered surface of the positioning shaft 6, the connecting rod 1 can have multiple degrees of freedom in axial, radial and angular directions, thereby removing the multi-directional force between the product and the fixture formed by welding deformation, making it much easier to loosen the positioning head and the product nozzle.

[0081] like Figure 9 The original positioning head assembly shown can only move axially. Before welding, the flange of the positioning shaft 6 is tightly fitted with the positioning sleeve 10, and the mutual force formed by welding deformation cannot be unloaded. Therefore, disassembling the product and the fixture is likely to cause damage to the product.

[0082] like Figure 6 The positioning head assembly shown is compared to the Figure 9 The positioning head assembly shown in the figure can release multiple degrees of freedom after welding is completed, which can more effectively unload the force between the product and the fixture, making it easy and convenient to disassemble the product.

[0083] In terms of specific design structure, by changing the form of the positioning flange 14, it can also be used for welding various forms of nozzles or joints.

[0084] This design form, in the case of a non-enclosed space, can directly install product parts on the position of the positioning flange 14 for positioning and tightening for welding.

[0085] The fourth embodiment of the present invention:

[0086] like Figure 8 The figure shows a schematic diagram of the positioning head structure with an external conical surface fit. The positioning head assembly structure includes a positioning shaft 6, an outer sleeve 11, a tapered sleeve 4, a pin 3, a sleeve 2, and a connecting rod 1. The positioning shaft 6 is a flanged shaft with an external thread at one end and a conical end. The tapered sleeve 4 is a hollow step sleeve with a tapered sleeve at one end, which fits with the positioning shaft 6 and a through hole at the other end. The sleeve pin 3 fits and fixes with the connecting rod 1. The outer sleeve 11 is a nut with an opening for pressing the tapered sleeve 4 onto the end of the positioning shaft 6. The connecting rod 1 is a flanged shaft. The sleeve 2 is a nut with an opening, which is limited to the flange of the connecting rod 1 and is used to install the fastening nozzle 8.

[0087] like Figure 8 The specific operation of using the locating head with external taper fit is as follows:

[0088] During the welding assembly stage, tighten the outer sleeve 11 so that the tapered sleeve 4 fits tightly with the positioning shaft 6 to achieve accurate radial and axial positioning, and move the positioning head assembly in the positioning sleeve 10 until the step of the positioning shaft 6 fits tightly with the positioning sleeve 10 and is locked; thereby, install the nozzle to be welded and tighten it with the corresponding tightening tool.

[0089] During the disassembly stage after welding, first loosen the outer sleeve 11 to loosen the cone sleeve 4 and the positioning shaft 6, thereby releasing the force between the product and the fixture; then loosen the sleeve 2 to loosen the product and the positioning head; then pull the positioning head assembly out of the outer sleeve 11 until it is separated from the product; and remove the product from the fixture.

[0090] By loosening the tapered sleeve 4 and the tapered surface of the positioning shaft 6, the connecting rod 1 can have multiple degrees of freedom in axial, radial and angular directions, thereby removing the multi-directional force between the product and the fixture formed by welding deformation, making it much easier to loosen the positioning head and the product nozzle.

[0091] like Figure 8 The positioning head assembly shown in the figure improves the original connection between the connecting rod 1 and the positioning shaft 6. The ordinary fixed form of equal diameter shaft hole with pin fixation is replaced by a tapered sleeve 4, which is improved to a movable form with tapered surface fit. It is fixed and loosened with an outer sleeve 11, which can achieve multi-directional adjustment and can completely unload the force between the product nozzle 8 and the positioning head assembly. Therefore, it is very easy to remove the product from the fixture, and the product and fixture will not be damaged due to large force and removal force. Compared with Figure 1The fixed positioning head shown retains its advantages of precision and good rigidity and inherits the basic form of axial sliding and positioning in the positioning sleeve 10 .

[0092] In the design structure, the angle of fit between the tapered sleeve 4 and the tapered surface of the positioning shaft 6 can be adjusted according to actual needs to meet the proportional requirements of axial and radial movement; it can also be used to meet the coordination requirements of axial tightening force and radial load-bearing capacity. Fastening with a threaded outer sleeve 11 provides a simple structure, reliable connection, and convenient operation.

[0093] The present invention is described in detail above with reference to the accompanying drawings or specific implementation cases. It should be noted that some (but not all) of the disclosed examples are shown in the accompanying drawings. In fact, many different examples can be described and these examples should not be understood as being limited to the examples set forth herein. On the contrary, describing these examples makes the positive effects of the present invention more apparent, and any parts not detailed herein are considered to be well-known techniques or conventional technical means in the art.

Claims

1. A floating adjustable positioning head assembly for an aviation heat exchanger welding fixture, comprising a positioning shaft (6), a screw plug (5), a tapered sleeve (4), a pin (3), a sleeve (2), a connecting rod (1), and a wrench (7). The positioning shaft (6) is a hollow shaft, the operating rod of the wrench (7) is arranged inside the positioning shaft (6), the tapered sleeve (4) is arranged on one end of the positioning shaft (6) with a conical surface, and is positioned by the conical surface, the screw plug (5) is a hollow external thread structure, and is arranged in the internal thread of the positioning shaft (6) through a threaded fit. The screw plug (5) clamps the tapered sleeve (4) through the closing mouth, the connecting rod (1) is arranged in the end hole of the tapered sleeve (4) with a transition fit, and is fixedly connected by a pin (3), and the sleeve (2) is an internal thread structure, arranged on the outside of the connecting rod (1), and is limited by the step of the connecting rod (1) to tighten the nozzle (8); the wrench (7) is rotated in the positioning shaft (6) and drives the tapered sleeve (4), which is tightened and loosened with the conical surface of the positioning shaft (6), and drives the connecting rod (1) and the sleeve (2), as well as the nozzle (8) to be fixed; The positioning shaft (6) is also provided with an axial limiting flange for positioning the positioning sleeve (10) of the fixture; A tapered hole is provided at one end of the positioning shaft (6) that cooperates with the tapered sleeve and is used to position the tapered sleeve (4); One end of the inner hole of the screw plug (5) is set as an inner hexagonal structure, and the end of the operating rod of the wrench (7) is a hexagonal structure, which matches the inner hexagonal screw plug (5); the other end of the inner hole of the screw plug (5) is set as a round hole with an outward convex step, which clamps the tapered sleeve (4) after closing; the connecting rod (1) is a shaft with a flange, which is used to position the nozzle (8).

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