Guide housing electrothermal riveting method

Abstract

This invention relates to the field of electrothermal riveting technology for parts, and discloses an electrothermal riveting method for a guide housing. This method involves riveting the inner mounting edge of the guide housing to the guide housing itself. The riveting is performed using an electrothermal riveting device, which includes an upper electrode and a lower electrode. Each rivet is riveted in two stages. The first riveting only needs to form the rivet head without causing cracks. The second riveting is performed to the required dimensions. By performing the riveting in two stages, defects such as cracks in the rivet head or slippage and non-roundness caused by excessive rivet extension, slight equipment instability, or insufficient cooling time when the rivet is under high pressure during heating and melting, which are common in traditional riveting operations, can be avoided. A tray ensures stable placement of the parts, guaranteeing that the parts are perpendicular to the upper and lower electrodes. Pre-drilled rivet holes on the lower electrode ensure stable and non-skewed placement of the rivets, guaranteeing that the fit between the rivets and parts meets requirements during assembly. The electrothermal riveting device significantly improves riveting efficiency.

Description

Technical Field

[0001] This invention relates to the field of electrothermal riveting technology for parts, and more specifically, to a method for electrothermal riveting of a guide housing. Background Technology

[0002] Electrothermal riveting is a process that uses the resistance heat generated when an electric current passes through a part as a heat source to heat the part to a plastic state or a partially melted state, while applying pressure to the riveted parts to cause plastic deformation and form a riveted joint.

[0003] Instruction manual attached Figure 2 and 3 The images show a semi-sectional view and a top view of an aero-engine guide housing. The guide housing 101 is connected to the inner mounting edge 104 of the guide housing by rivets, with a total of five rivets. It is necessary to ensure that the height and diameter of the riveted head meet the requirements after riveting, and that the axial clearance of the inner mounting edge 104 of the guide housing is between 0.05 and 0.25 mm after riveting.

[0004] Because the riveting process requires maintaining a horizontal position, ensuring the riveted head is a complete semi-circular head, and preventing cracks, the clamping requirements for the parts are quite high. Conventional methods involve manually holding the parts during processing, which makes it difficult to ensure the parts are horizontal. Furthermore, during the downward pressing of the electrode head, the upper electrode exerts a large downward pressure, resulting in significant deflection at the lever arm and potential slippage, making it impossible to maintain a horizontal riveting position for the parts.

[0005] Furthermore, traditional riveting methods require a single, precise riveting operation with stringent parameter requirements. During riveting, the rivet extends too far, and even slight instability in the riveting equipment, combined with the molten rivet's insufficient cooling time under pressure, can lead to defects such as cracks in the riveted head and slippage due to rivet softening. Moreover, a single riveting operation leaves no room for movement. Often, after riveting several satisfactory pieces, subsequent processing using the same parameters results in dimensional inaccuracies, cracks, and incorrect riveted head dimensions. This necessitates frequent rivet replacements and re-riveting at the same location, increasing costs and compromising reliability.

[0006] Patent CN208305837U discloses a hot riveting electrode, which addresses the riveting requirements of turbine casing components. It primarily solves the problem of dimensional control difficulties after hot riveting by improving the electrode structure. However, casing components are typically large, and the patent does not address how to maintain horizontality during riveting. If manual operation is still used, it inevitably leads to misalignment of the casing components. Furthermore, ensuring excellent riveting of casing parts without significantly improving the electrode, thus enhancing the versatility of electrothermal riveting for casings, remains a challenge. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide an efficient guide housing electrothermal riveting method that can guarantee the stability of riveting quality.

[0008] The objective of this invention is achieved through the following technical solution:

[0009] A method for electrothermal riveting of a guide housing is provided for riveting the inner mounting edge of the guide housing to the guide housing. The riveting is performed using an electrothermal riveting device, which includes an upper electrode and a lower electrode. Each rivet is riveted in two steps. The first riveting only needs to form the rivet head without causing cracks. The second riveting is performed to the required dimensions.

[0010] Furthermore, the parameters for the first riveting are set as follows: Before riveting, the rivets are preheated and pre-pressed, with a preheating time of 55-60 ms, a preheating current of 1.5-2.5 kA, and a pre-pressing time of 550-650 ms. Subsequently, pressure is applied and welding is performed, with a pressure application time of 480-550 ms, a welding pressure of 7.5-9 kN, a welding time of 120-160 ms, and a welding current of 2-3 kA. The starting and ending currents for the first riveting are both 3 kA, and the contact maintenance time between the upper and lower electrodes and the guide housing is 480-550 ms.

[0011] Furthermore, the parameters for the second riveting are set as follows: Before riveting, the rivets are preheated and pre-pressed, with a preheating time of 55-60ms, a preheating current of 1.5-2.5KA, and a pre-pressing time of 480-550ms. Subsequently, pressure is applied and welding is performed, with a pressure application time of 480-550ms, a welding pressure of 8.5-9.5KN, a welding time of 180-220ms, and a welding current of 4-4.5KA. The starting and ending currents for the second riveting are both 0, and the contact maintenance time between the upper and lower electrodes and the guide housing is 480-550ms.

[0012] Furthermore, after completing the first riveting of each rivet in sequence, the second riveting is then completed in sequence.

[0013] Furthermore, the electrothermal riveting device also includes a tray for placing the guide housing. The upper surface of the tray contacts the lower end face of the guide housing. A through hole is provided on the tray for the lower electrode to pass through. The upper end face of the lower electrode is provided with a rivet hole for the rivet to be placed stably.

[0014] Furthermore, the clearance between the lower electrode and the through hole on the tray is less than or equal to 0.05 mm.

[0015] Furthermore, the electrothermal riveting device also includes a fastening connector for fixing the position of the auxiliary tray. The fastening connector is set on the tray and abuts or snaps against the lower electrode.

[0016] Furthermore, the fastening connector is a fastening screw, and the tray has a threaded hole that is perpendicular to the through hole. The fastening screw extends into the threaded hole and abuts against the lower electrode.

[0017] Furthermore, the fastening connector is a clamp, which is located below the tray.

[0018] Furthermore, after the guide housing is placed stably on the tray, the guide housing and the tray need to be manually pressed and rotated. After confirming that there is no interference, the riveting can be carried out.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] The electrothermal riveting method of the present invention, by performing riveting in two stages, can effectively avoid the defects of traditional single riveting operation, where the rivet is subjected to great pressure in a heated and molten state and cannot cool down in time, resulting in cracks in the riveting head or the rivet becoming soft and slipping out of round, thus failing to achieve the required riveting size.

[0021] The tray in the electrothermal riveting device ensures the stability of the parts and guarantees that the parts are perpendicular to the upper and lower electrodes. The pre-drilled rivet holes on the lower electrode ensure that the rivets are placed stably without tilting, thus ensuring that the fit between the rivets and the parts meets the requirements during assembly. The introduction of the electrothermal riveting device reduces the time spent by manual leveling and adjusting the parts and rivets, and greatly improves the riveting efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the electrothermal riveting device structure for the guide housing electrothermal riveting method in Example 1;

[0023] Figure 2 This is a side sectional view of the guide housing in Example 1;

[0024] Figure 3 for Figure 2 Top view of the center guide housing. Detailed Implementation

[0025] To clearly illustrate the technical features of this solution, the following detailed description, in conjunction with the accompanying drawings, will explain the technical solution in detail.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein. Therefore, the scope of protection of this application is not limited to the specific embodiments disclosed below.

[0027] Furthermore, it should be understood in the description of this application that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0028] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0029] In this application, unless otherwise expressly specified and limited, the "above" or "below" of the second feature can mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0030] Example 1

[0031] An electrothermal riveting method is provided for riveting the inner mounting edge of the guide housing to the guide housing, such as... Figure 2 and Figure 3 As shown, the inner mounting edge 104 is riveted to the casing 101 by five rivets 102. The riveting is performed using an electrothermal riveting device, as shown below. Figure 1As shown, the electrothermal riveting device includes an upper electrode d, a lower electrode b, and a tray c for placing the guide housing. The upper end face of the lower electrode is provided with a rivet hole for the rivet to be placed stably.

[0032] The upper and lower electrodes are clamped using a resistance spot welding machine and contact the machine tool handle, ensuring a contact area of ​​over 65%. The upper surface of tray c contacts the lower end face of housing 101. A through hole is provided on the tray for the lower electrode b to pass through, and tray c is also fitted onto the lower electrode b through this through hole. The electrothermal riveting device also includes a fastening connector a to assist in fixing the position of the tray. In this embodiment, fastening connector a is a fastening screw. A threaded hole perpendicular to the through hole is provided on tray c, and the fastening screw extends into the threaded hole and abuts against the outer circumferential surface of the lower electrode b. By tightening the fastening nut and fastening screw, it can be ensured that the lower electrode and the tray will not wobble. The clearance between the lower electrode and the through hole on the tray is less than or equal to 0.05 mm.

[0033] Each rivet on the casing is riveted in two stages. The first riveting only needs to shape the rivet head and prevent cracks. The second riveting is done to the correct dimensions. In each case, the first riveting is completed for each rivet in sequence, followed by the second riveting.

[0034] See Figure 1 After the upper electrode, lower electrode, and tray are installed, adjust the two electrodes to ensure they are on the same center line. Visually inspect that the upper electrode is pressed down and is in horizontal contact with the end face of the lower electrode to ensure complete contact during the pressing process. Then, invert the rivet into the rivet hole of the lower electrode, and then place the guide housing and inner mounting edge in sequence to pre-assemble them onto the rivet.

[0035] After the guide housing is placed stably on the tray, it is necessary to manually press the guide housing and the tray together with both hands and rotate them. After confirming that there is no interference, the upper electrode is lowered for riveting. Visually, the housing and the tray should be horizontal and the housing and the upper electrode should be perpendicular.

[0036] After adjusting the resistance spot welding machine, set the welding parameters. Since riveting is performed in two stages, two sets of parameters need to be set for processing. The parameters for the first riveting are set as follows: Before riveting, preheat and pre-press the rivet. The preheating time is 60ms, the preheating current is 2KA, and the pre-pressing time is 600ms. Then, pressurize and weld. The pressurization time is 500ms, the welding pressure is 8.3KN, the welding time is 150ms, and the welding current is 2.4KA. The starting current and ending current for the first riveting are both 3KA, and the contact time between the upper and lower electrodes and the guide housing is 500ms. During riveting, grip the housing and tray firmly with both hands, step on the foot switch of the resistance spot welding machine, and the upper and lower electrodes press the rivet to energize for the first electrothermal riveting.

[0037] The initial riveting dimensions are controlled by the aforementioned parameters, which play a decisive role in the riveting effect. If the parameters are too small, the rivet head 103 will be too high and cannot be pressed down; if the parameters are too large, the rivet head 103 will be directly flattened, resulting in cracks. In this embodiment, the parameters ensure that the riveted head size after the first riveting is within Ф6.8±0.2.

[0038] After the first riveting of the current rivet is completed, the upper electrode is lifted, the housing is removed, and the rivet is repositioned in the rivet hole of the lower electrode. The housing is rotated, and the next rivet is riveted. After the first riveting of all 5 rivets is completed and the housing has cooled down, the parameters are adjusted to the second set of parameters. The parameter settings for the second riveting are as follows: the rivet is preheated and pre-pressurized before riveting, with a preheating time of 60ms, a preheating current of 2KA, and a pre-pressurization time of 500ms. Then, pressure is applied and welding is performed, with a pressure of 500ms, a welding pressure of 9KN, a welding time of 200ms, and a welding current of 4.15KA. The starting current and ending current of the second riveting are both 0, and the contact maintenance time between the upper and lower electrodes and the guide housing is 500ms. The above parameter settings can ensure that the final riveting size of the rivet head is Ф7 (-0.2, +0.8) and the height is 2±0.2, which meets the technical requirements. In addition, the casing and the inner mounting edge have axial movement, which is specifically ensured by the assembly clearance and the degree of riveting.

[0039] Example 2

[0040] An electrothermal riveting method for riveting the inner mounting edge of the guide housing to the guide housing, such as... Figure 2 and Figure 3 As shown, the inner mounting edge 104 is riveted to the casing 101 by five rivets 102. The riveting is performed using an electrothermal riveting device, as shown below. Figure 1 As shown, the electrothermal riveting device includes an upper electrode, a lower electrode, and a tray for placing the guide housing. The upper end face of the lower electrode is provided with a rivet hole for the rivet to be placed stably.

[0041] The upper and lower electrodes are clamped using a resistance spot welding machine and contact the machine tool handle, ensuring a contact area of ​​over 65%. The upper surface of the tray contacts the lower end face of the guide housing. A through hole is provided on the tray for the lower electrode to pass through, and the tray is also fitted onto the lower electrode through this through hole. The electrothermal riveting device also includes a fastening connector to help fix the tray position. In this embodiment, the fastening connector is a fastening screw. A threaded hole perpendicular to the through hole is provided on the tray, and the fastening screw extends into the threaded hole and abuts against the outer circumferential surface of the lower electrode. By tightening the fastening nut and fastening screw, it can be ensured that the lower electrode and the tray will not wobble. The clearance between the lower electrode and the through hole on the tray is less than or equal to 0.05 mm.

[0042] Each rivet on the casing is riveted in two stages. The first riveting only needs to shape the rivet head and prevent cracks. The second riveting is done to the correct dimensions. In each case, the first riveting is completed for each rivet in sequence, followed by the second riveting.

[0043] See Figure 1 After the upper electrode, lower electrode, and tray are installed, adjust the two electrodes to ensure they are on the same center line. Visually inspect that the upper electrode is pressed down and is in horizontal contact with the end face of the lower electrode to ensure complete contact during the pressing process. Then, invert the rivet into the rivet hole of the lower electrode, and then place the guide housing and inner mounting edge in sequence to pre-assemble them onto the rivet.

[0044] After the guide housing is placed stably on the tray, it is necessary to manually press the guide housing and the tray together with both hands and rotate them. After confirming that there is no interference, the upper electrode is lowered for riveting. Visually, the housing and the tray should be horizontal and the housing and the upper electrode should be perpendicular.

[0045] After adjusting the resistance spot welding machine, the welding parameters are set. Since riveting is performed in two stages, two sets of parameters need to be set for processing. The difference between this embodiment and Embodiment 1 is that the riveting parameters are different: the parameters for the first riveting are set as follows: before riveting, the rivet is preheated and pre-pressed, with a preheating time of 55ms, a preheating current of 1.5KA, and a pre-pressing time of 550ms. Then, pressure is applied and welding is performed, with a pressure of 480ms, a welding pressure of 7.5KN, a welding time of 120ms, and a welding current of 2KA. The starting current and ending current for the first riveting are both 3KA, and the contact time between the upper and lower electrodes and the guide housing is 480ms. During riveting, both hands grip the housing and tray firmly, and the foot switch of the resistance spot welding machine is pressed down. The upper and lower electrodes press the rivet and are energized for the first electrothermal riveting.

[0046] The initial riveting dimensions are controlled by the aforementioned parameters, which play a decisive role in the riveting effect. If the parameters are too small, the rivet head 103 will be too high and cannot be pressed down; if the parameters are too large, the rivet head 103 will be directly flattened, resulting in cracks. In this embodiment, the parameters ensure that the riveted head size after the first riveting is within Ф6.8±0.2.

[0047] After the first riveting of the current rivet is completed, the upper electrode is lifted, the housing is removed, and the rivet is repositioned in the rivet hole of the lower electrode. The housing is rotated, and the next rivet is riveted. After the first riveting of all 5 rivets is completed and the housing has cooled down, the parameters are adjusted to the second set of parameters. The parameters for the second riveting are set as follows: the rivet is preheated and pre-pressurized before riveting, with a preheating time of 55ms, a preheating current of 1.5KA, and a pre-pressurization time of 480ms. Then, pressure is applied and welding is performed, with a pressure of 480ms, a welding pressure of 8.5KN, a welding time of 180ms, and a welding current of 4KA. The starting and ending currents for the second riveting are both 0, and the contact time between the upper and lower electrodes and the guide housing is 480-550ms. The above parameter settings can ensure that the final riveting size of the rivet head is Ф7 (-0.2, +0.8) and the height is 2±0.2, which meets the technical requirements. In addition, the casing and the inner mounting edge have axial movement, which is specifically ensured by the assembly clearance and the degree of riveting.

[0048] Example 3

[0049] The difference between this embodiment and Embodiment 1 lies in the riveting parameters. The parameters for the first riveting are as follows: Before riveting, the rivet is preheated and pre-pressed for 60ms, with a preheating current of 2.5KA and a pre-pressing time of 650ms. Then, pressure is applied and welding is performed: pressure for 550ms, welding pressure of 9KN, welding time of 160ms, and welding current of 3KA. The starting and ending currents for the first riveting are both 3KA, and the contact time between the upper and lower electrodes and the guide housing is 550ms. During riveting, both hands grip the housing and tray, and the foot switch of the resistance spot welding machine is activated. The upper and lower electrodes press the rivet and energize for the first electrothermal riveting.

[0050] The parameters for the second riveting are set as follows: Before riveting, the rivets are preheated and pre-pressed. The preheating time is 60ms, the preheating current is 2.5KA, and the pre-pressing time is 550ms. Then, pressure is applied and welding is performed. The pressure is applied for 550ms, the welding pressure is 9.5KN, the welding time is 220ms, and the welding current is 4.5KA. The starting current and ending current of the second riveting are both 0. The contact maintenance time between the upper and lower electrodes and the guide housing is 550ms.

[0051] Example 4

[0052] The difference between this embodiment and embodiment 1 is that the fastening connector is a clamp, which is located below the tray. After the tray and the lower electrode are assembled, the clamp is fastened to the outer periphery of the lower electrode to fix the position of the tray and the lower electrode.

[0053] Obviously, the above embodiments are merely examples to clearly illustrate the technical solutions of the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for electrothermal riveting of a guide housing, used to rivet the inner mounting edge of the guide housing to the guide housing, characterized in that, The process employs an electrothermal riveting device, which includes an upper electrode, a lower electrode, and a tray for placing the guide housing. The upper surface of the tray contacts the lower end face of the guide housing. A through hole is provided on the tray for the lower electrode to pass through, and the upper end face of the lower electrode has a rivet hole for stable placement of the rivet. The device also includes a fastening connector to assist in fixing the position of the tray. The fastening connector is set on the tray and abuts or snaps against the lower electrode. Each rivet is riveted in two stages. The first riveting only needs to form the rivet head without causing cracks, while the second riveting is done to the required dimensions. The parameters for the first riveting are set as follows: Before riveting, the rivets are preheated and pre-pressed. The preheating time is 55~60ms, the preheating current is 1.5~2.5KA, and the pre-pressing time is 550~650ms. Then, pressure is applied and welding is performed. The pressure application time is 480~550ms, the welding pressure is 7.5~9KN, the welding time is 120~160ms, and the welding current is 2~3KA. The starting current and ending current of the first riveting are both 3KA, and the contact maintenance time between the upper and lower electrodes and the guide housing is 480~550ms. The parameters for the second riveting are set as follows: Before riveting, the rivets are preheated and pre-pressed. The preheating time is 55~60ms, the preheating current is 1.5~2.5KA, and the pre-pressing time is 480~550ms. Then, pressure is applied and welding is performed. The pressure application time is 480~550ms, the welding pressure is 8.5~9.5KN, the welding time is 180~220ms, and the welding current is 4~4.5KA. The starting current and ending current of the second riveting are both 0. The contact time between the upper and lower electrodes and the guide housing is 480~550ms. After completing the first riveting of each rivet in sequence, the second riveting is then completed in sequence.

2. The guide housing electrothermal riveting method according to claim 1, characterized in that, The clearance between the lower electrode and the through hole on the tray is less than or equal to 0.05 mm.

3. The guide housing electrothermal riveting method according to claim 1, characterized in that, The fastening connector is a fastening screw. The tray has a threaded hole that is perpendicular to the through hole. The fastening screw extends into the threaded hole and abuts against the lower electrode.

4. The guide housing electrothermal riveting method according to claim 1, characterized in that, The fastening connector is a clamp, which is located under the tray.

5. The guide housing electrothermal riveting method according to claim 1, characterized in that, After the guide housing is placed stably on the tray, the guide housing and the tray need to be manually pressed and rotated. After confirming that there is no interference, the riveting can be carried out.

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