A reverse pull nut, reverse pull nut installation process and device

Abstract

This invention discloses a reverse rivet nut, a reverse rivet nut installation process and device, applied in the field of rivet nut technology. The key technical points are: it includes a head flange and a rod fixedly connected to the head flange; a straight-tooth limiting part for anti-torsion is provided on the outer circumferential surface of the rod; a dovetail groove is provided at the connection between the rod and the head flange, the groove opening facing the head flange and the inner diameter of the groove gradually increasing away from the groove opening; during reverse riveting, the plastic deformation area of ​​the sheet metal to be processed is squeezed into the dovetail groove to achieve axial limiting; and a threaded inner hole penetrating the head flange and the rod along the axial direction is also provided. The technical effects are: improved anti-torsion and anti-push performance of the rivet nut in thin-walled tubular structures, and optimization of the limitations of riveting in confined spaces.

Description

Technical Field

[0001] This invention relates to the field of rivet nut technology, and particularly to a reverse rivet nut, a reverse rivet nut installation process, and a device. Background Technology

[0002] Rivet nuts are fasteners that can be installed on one side of a workpiece and are widely used in the connection of thin plates or thin tubes in industries such as automobiles, aviation, furniture, and electrical appliances. In the automotive manufacturing industry, the dashboard crossbeam, as a core mounting carrier for automotive interior parts and control components, requires the installation of multiple nuts within a closed or semi-closed tubular structure to subsequently secure components such as the instrument panel and steering column. Due to the limited operating space inside the tubular structure, applying traditional rivet nuts to the dashboard crossbeam presents several challenges. Firstly, ordinary rivet nuts rely primarily on the friction between the bulge or uptake formed after riveting and the workpiece hole wall to resist torque. However, under significant tightening torque or vibration loads, the nut is prone to rotation within the hole, leading to connection failure. Although some rivet nuts feature knurled or serrated edges on the shank, the material... Due to limitations in material flow, these tooth profiles often cannot be fully and evenly embedded into the workpiece plate, resulting in limited torsional resistance and severely affecting the connection stability of the rivet nut. On the other hand, the push-out resistance of ordinary rivet nuts mainly depends on the clamping force of the lower flange or bulge formed after riveting on the back of the plate. However, the bulge size that can be formed for the low-thickness steel or aluminum plates commonly used in instrument panel beams is limited, causing the nut to be easily pulled out when subjected to a large axial thrust, thus severely affecting the connection firmness of the rivet nut. Therefore, it is necessary to improve the existing rivet nut structure and installation process to solve the problem of poor torsional and push-out resistance of existing rivet nuts in thin-walled tubular structures. Summary of the Invention

[0003] The first objective of this invention is to provide a reverse rivet nut, which has the advantage of improving the torsional and thrust resistance of the rivet nut in thin-walled tubular structures.

[0004] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a reverse rivet nut, comprising: Head flange; The rod is fixedly connected to the head flange and is used to abut against the inner wall of the plate. The outer circumferential surface of the rod is provided with a straight tooth limiting part for anti-torsion function. A dovetail groove is provided at the connection between the rod and the head flange. The opening of the dovetail groove faces the head flange and the inner diameter of the dovetail groove gradually increases in the direction away from the opening. It is used to squeeze the plastic deformation area of ​​the plate to be installed into the dovetail groove during reverse riveting to achieve axial positioning. The threaded inner hole penetrates the head flange and the rod along the axial direction.

[0005] The present invention is further configured such that: the rod portion has a polygonal structure, and the bottom of the dovetail groove extends into the rod portion.

[0006] The present invention is further configured such that: the straight tooth limiting part is circumferentially disposed at the center of the outer side wall of the rod, and is used to embed the tooth block in the plate, the edge of the tooth block extends to the side wall of the head flange, and the thickness of the tooth block is lower than the thickness of the rod.

[0007] The present invention is further configured such that: the maximum cavity diameter of the dovetail groove is greater than the groove opening diameter, and one side wall of the dovetail groove forms an angle with the axial direction of the head flange, the angle being 15°-45°.

[0008] The invention is further configured such that: the end of the rod away from the head flange is provided with an arc-shaped guide portion for guiding the reverse rivet nut into a pre-drilled hole on the plate to be processed, and the outer diameter of the arc-shaped guide portion is smaller than the outer diameter of the main body of the rod.

[0009] The second objective of this invention is to provide a reverse rivet nut installation process, which has the advantage of improving the torsional and thrust resistance of the rivet nut in thin-walled tubular structures.

[0010] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a reverse rivet nut installation process for installing a reverse rivet nut as described in any of the above technical solutions; comprising: Step 1: Machining pre-drilled holes on the material to be processed; Step 2: Insert the shank of the reverse rivet nut into the pre-drilled hole and make the head flange fit against the back surface of the plate to be processed; Step 3: Connect and fix the rivet rod of the rivet gun to the threaded inner hole; Step 4: Start the rivet gun. The rivet rod applies a reverse pulling force to the reverse rivet nut in the opposite direction to the head flange. Under the action of the reverse pulling force, the plate undergoes plastic deformation around the pre-made hole. Part of the plate material is pulled in and filled into the dovetail groove. At the same time, the straight tooth limiting part is embedded in the plate. Step 5: Stop applying force with the rivet gun, unscrew the rivet screw in the opposite direction to complete the installation of the reverse rivet nut.

[0011] The present invention is further configured such that: in step 1, the plate material is aluminum alloy, and when the plate to be processed undergoes plastic deformation, the dovetail groove is completely filled by the plate material.

[0012] The present invention is further configured such that: in step 4, when the reverse rivet nut applies a force to the plate in the direction opposite to the head flange, the rivet gun simultaneously applies a positive pressure to the surface of the plate in the direction facing the head flange and inclined relative to the central axis of the reverse rivet nut. The positive pressure and the reverse tension respectively squeeze the plate around the pre-drilled hole from the front and back sides of the plate to cause plastic deformation so that the plate material fills into the dovetail groove.

[0013] A third objective of this invention is to provide a reverse rivet nut mounting device, which has the advantage of improving the torsional and thrust resistance of rivet nuts in thin-walled tubular structures.

[0014] The above-mentioned technical objective of the present invention is achieved through the following technical solution: a reverse rivet nut installation device for installing a reverse rivet nut installation process as described in any of the above technical solutions; comprising: The body of the rivet gun; A rivet rod is concentrically mounted on the rivet gun, and the rivet rod has a connecting end that mates with the threaded inner hole; The abutment sleeve is fixedly connected to the rivet gun body and is used to abut the sheet metal to be processed.

[0015] In summary, the present invention has the following beneficial effects: 1. By setting a dovetail groove structure with the groove facing the head flange at the connection between the head flange and the rod, a reverse pulling force is applied by the rivet gun during the reverse riveting operation, causing the sheet material to actively undergo plastic deformation to directly squeeze into and fill the dovetail groove cavity, thereby forming an axial limit for the reverse rivet nut. At the same time, a polygonal rod is set with a straight tooth limiting part for embedding the toothed block into the sheet material at the center of the outer wall of the rod. By embedding the rod and the straight tooth limiting part into the deformed sheet material and locking it, the torsional resistance of the reverse rivet nut is improved, significantly improving the connection reliability and stability of the reverse rivet nut in thin-walled tubular structures, and solving the problems of rotation and pull-out that are easy to occur with traditional nuts in scenarios such as instrument panel crossbeams. 2. By applying reverse tension to the reverse rivet nut with the rivet rod, and simultaneously applying positive pressure to the plate surface facing the head flange and set at an angle, the plastic deformation of the plate around the pre-drilled hole is made more uniform and controllable through bidirectional extrusion. At the same time, it can fill the dovetail groove more quickly and stably, further improving the stability of the installation quality. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the reverse rivet nut of Example 1; Figure 2 This is a structural cross-sectional view of the reverse rivet nut of Embodiment 1; Figure 3 This is a schematic diagram of the overall structure of Example 3.

[0017] Reference numerals: 1. Head flange; 2. Rod; 3. Straight tooth limiting part; 4. Dovetail groove; 5. Threaded inner hole; 6. Arc-shaped guide part; 7. Plate to be processed; 8. Pre-drilled hole; 9. Riveting gun body; 10. Riveting rod; 11. Abutment sleeve. Detailed Implementation

[0018] The present invention will be further described in detail below with reference to the accompanying drawings.

[0019] Example 1: refer to Figure 1 A reverse rivet nut includes a head flange 1 and a rod 2 fixedly connected to the head flange 1 for abutting against the inner wall of a sheet metal. A straight-tooth limiting part 3 for anti-torsion is provided on the outer circumferential surface of the rod 2. A dovetail groove 4 is formed at the connection between the rod 2 and the head flange 1. The opening of the dovetail groove 4 faces the head flange 1, and the inner diameter of the groove gradually increases away from the opening. During reverse rivet installation, the plastic deformation area of ​​the sheet metal to be installed is squeezed into the dovetail groove 4 to achieve axial limiting. The rod 2 has a polygonal structure, and the bottom of the dovetail groove 4 extends into the rod 2. The rod 2 can have a regular polygonal structure or a non-regular polygonal structure. The structure is polygonal and also has a threaded inner hole 5 that passes through the head flange 1 and the rod 2 along the axial direction. By connecting the head flange 1 and the rod 2, a dovetail groove 4 with the groove facing the head flange 1 is formed. In the reverse riveting operation, the reverse tension is applied by the rivet gun, which causes the plate material to actively undergo plastic deformation so that it can be directly squeezed into and filled into the dovetail groove 4. This forms an axial limit for the reverse rivet nut. At the same time, the straight tooth limit part 3 is embedded in the plate to achieve circumferential limit, which prevents the reverse rivet nut from twisting. This significantly improves the connection reliability and stability of the reverse rivet nut in thin-walled tubular structures.

[0020] The straight tooth limiting part 3 is circumferentially set at the center of the outer wall of the rod part 2, and is used to embed the tooth block in the plate. The edge of the tooth block extends to the side wall of the head flange 1. The thickness of the tooth block is lower than the thickness of the rod part 2. When the plate is deformed, the polygonal rod part 2 is embedded into the deformed plate and locked, thereby improving the anti-torsion performance of the reverse rivet nut. The non-regular polygonal rod part 2 can further improve the locking effect.

[0021] The maximum cavity diameter of the dovetail groove 4 is greater than the groove opening diameter. The single-sided groove wall of the dovetail groove 4 forms an angle with the axial direction of the head flange 1, with the angle being 15°-45°. This ensures that the plate material can fully and evenly fill the dovetail groove 4 under the action of reverse tension, forming a strong dovetail tenon structure.

[0022] The end of the rod 2 away from the head flange 1 is provided with an arc-shaped guide 6 for guiding the reverse rivet nut into the pre-drilled hole 8 on the plate 7 to be processed. The outer diameter of the arc-shaped guide 6 is smaller than the outer diameter of the main body of the rod 2. By setting the arc-shaped guide 6, it is easier to insert the reverse rivet nut into the pre-drilled hole 8.

[0023] Example 2: refer to Figure 3 A reverse rivet nut installation process, used for installing a reverse rivet nut as shown in Example 1, includes: Step 1: Machining pre-drilled holes 8 on the sheet material 7 to be processed; Step 2: Insert the rod 2 of the reverse rivet nut into the pre-drilled hole 8 and make the head flange 1 fit against the back surface of the plate 7 to be processed; Step 3: Connect and fix the rivet rod 10 of the rivet gun to the threaded inner hole 5 with a thread; Step 4: Start the rivet gun. The rivet rod 10 applies a reverse pulling force to the reverse rivet nut in the opposite direction to the head flange 1. Under the action of the reverse pulling force, the plate undergoes plastic deformation around the pre-drilled hole 8. Part of the plate material is pulled in and filled into the dovetail groove 4. At the same time, the straight tooth limiting part 3 is embedded in the plate. Step 5: Stop applying force with the rivet gun, unscrew the rivet screw in the opposite direction to complete the installation of the reverse rivet nut.

[0024] Specifically, in step 1, the plate material is aluminum alloy, which ensures that the plate can undergo rapid plastic deformation when subjected to force. When the plate 7 to be processed undergoes plastic deformation, the dovetail groove 4 is completely filled by the plate material.

[0025] In step 2, for the pre-drilled holes 8 near the edge, the head flange 1 is manually held or clamped and the reverse rivet nut is inserted into the plate from the edge until the arc-shaped guide 6 contacts the pre-drilled hole 8. At this point, the rod 2 is pushed into the pre-drilled hole 8 to complete the pre-installation of the reverse rivet nut. For semi-enclosed plates deeper inside, flexible grippers or vacuum suction pens are used to clamp and transport the rivet nut to a designated position to achieve the pre-installation of the reverse rivet nut. Specifically, in step 4, when the reverse rivet nut applies a force to the plate in the direction opposite to the head flange 1, the rivet gun simultaneously applies a positive pressure to the surface of the plate facing the head flange 1 and inclined relative to the central axis of the reverse rivet nut. The positive pressure and the reverse tension squeeze the plate around the pre-drilled hole 8 from the front and back of the plate, respectively, causing plastic deformation so that the plate material fills into the dovetail groove 4. Through bidirectional extrusion, the plastic deformation of the plate around the pre-drilled hole 8 is more uniform and controllable, and the dovetail groove 4 can be filled more quickly and stably. The pressure in the inclined direction of the positive pressure can be achieved by attaching an accessory to the rivet gun. The accessory is set with an inclined abutment part inclined relative to the central axis of the reverse rivet nut, which can apply an inclined downward pressure to the surface of the processed plate 7, further improving the stability and efficiency of the installation quality.

[0026] Example 3: refer to Figure 3 A reverse rivet nut installation device is used to install a reverse rivet nut installation process as shown in Embodiment 2. It includes a rivet gun body 9 and a rivet rod 10 concentrically arranged on the rivet gun. The rivet rod 10 is provided with a connecting end that mates with the threaded inner hole 5. An abutment sleeve 11 for abutting against the receiving plate 7 is also fixedly connected to the rivet gun body 9.

[0027] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make inventive modifications to this embodiment as needed, but as long as they are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A reverse torque nut, characterized in that, include: Head flange (1); The rod (2) is fixedly connected to the head flange (1) and is used to abut against the inner wall of the plate. The outer circumferential surface of the rod (2) is provided with a straight tooth limiting part (3) for anti-torsion function. A dovetail groove (4) is provided at the connection between the rod (2) and the head flange (1). The opening of the dovetail groove (4) is opened in the direction of the head flange (1), and the inner diameter of the dovetail groove (4) gradually increases in the direction away from the opening. It is used to squeeze the plastic deformation area of ​​the plate to be installed into the dovetail groove (4) during reverse riveting to achieve axial positioning. The threaded inner hole (5) penetrates the head flange (1) and the rod (2) along the axial direction.

2. The reverse rivet nut according to claim 1, characterized in that, The rod (2) has a polygonal structure, and the bottom of the dovetail groove (4) extends into the rod (2).

3. A reverse rivet nut according to claim 2, characterized in that, The straight tooth limiting part (3) is circumferentially arranged at the center of the outer side wall of the rod (2) and is used to embed the tooth block in the plate. The edge of the tooth block extends to the side wall of the head flange (1) and the thickness of the tooth block is lower than the thickness of the rod (2).

4. A reverse rivet nut according to claim 1, characterized in that, The maximum cavity diameter of the dovetail groove (4) is greater than the groove opening diameter. The single-sided groove wall of the dovetail groove (4) forms an angle with the central axis of the head flange (1), with the angle being 15°-45°.

5. A reverse rivet nut according to claim 1, characterized in that, The rod (2) is provided with an arc-shaped guide (6) at one end away from the head flange (1) for guiding the reverse rivet nut into the pre-drilled hole (8) on the plate to be processed (7). The outer diameter of the arc-shaped guide (6) is smaller than the outer diameter of the main body of the rod (2).

6. A reverse rivet nut installation process for installing a reverse rivet nut as described in any one of claims 1-5; characterized in that, include: Step 1: Machining pre-drilled holes (8) on the material to be processed (7); Step 2: Insert the rod (2) of the reverse rivet nut into the pre-made hole (8) and make the head flange (1) fit against the back surface of the plate to be processed (7); Step 3: Connect and fix the rivet rod (10) of the rivet gun to the threaded inner hole (5) by threading; Step 4: Start the rivet gun. The rivet rod (10) applies a reverse pulling force to the reverse rivet nut in the direction opposite to the head flange (1). Under the action of the reverse pulling force, the plate undergoes plastic deformation around the pre-made hole (8). Part of the plate material is pulled into and filled into the dovetail groove (4). At the same time, the straight tooth limiting part (3) is embedded in the plate. Step 5: Stop applying force with the rivet gun, unscrew the rivet screw in the opposite direction to complete the installation of the reverse rivet nut.

7. The reverse rivet nut installation process according to claim 6, characterized in that, In step 1, the plate material is aluminum alloy. When the plate to be processed (7) undergoes plastic deformation, the dovetail groove (4) is completely filled by the plate material.

8. The reverse rivet nut installation process according to claim 6, characterized in that, In step 4, when the reverse rivet nut applies a force to the plate in the direction opposite to the head flange (1), the rivet gun simultaneously applies a positive pressure to the surface of the plate in the direction facing the head flange (1) and inclined relative to the central axis of the reverse rivet nut. The positive pressure and the reverse tension squeeze the plate around the pre-drilled hole (8) from the front and back of the plate, respectively, to cause plastic deformation so that the plate material fills into the dovetail groove (4).

9. A reverse rivet nut mounting device, used for installing a reverse rivet nut mounting process as described in any one of claims 7-8; characterized in that, include: Rivet gun body (9); A rivet rod (10) is concentrically arranged on the rivet gun body (9), and the rivet rod (10) is provided with a connecting end that mates with the threaded inner hole (5); The abutment sleeve (11) is fixedly connected to the rivet gun body (9) and is used to abut against the sheet metal (7) to be processed.

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