Method for joining a perforated nut to a laminated plate workpiece

Abstract

The present invention provides a method for joining a tapped nut to a laminated body of plate-like workpieces in a manner that exhibits high joining strength, the method for joining a tapped nut (1) having: a first riveting process for joining the tapped nut (1) to a first plate-like workpiece (W1) by punching the first plate-like workpiece (W1) into a circular shape and extending the periphery of the punched portion within a ring-shaped hollow portion (4) of the tapped nut (1); and a second riveting process for punching a second plate-like workpiece (W2) into a circular shape and extending the periphery of the punched portion within the ring-shaped hollow portion (4) of the tapped nut (1) outside the extended portion (W 1f ) of the first plate-like workpiece (W1).

Description

Technical Field

[0001] This invention relates to a joining method for joining a perforated nut with a threaded hole to a plate-shaped workpiece. Background Technology

[0002] As an existing perforated nut, such as Patent Document 1, the following structure is known: a screw through hole is provided in the center of the nut body which is formed into a flat cylindrical shape, the upper side of the screw through hole is formed into a cylindrical shape that narrows downward (i.e., a cylindrical shape whose diameter gradually decreases from the outside to the inside), and an annular groove is provided on the outer side of the cylindrical shape.

[0003] Furthermore, when such a perforated nut is joined to a plate-shaped workpiece, a cylindrical riveting die with approximately the same inner diameter as the cylindrical portion surrounding the screw through hole is driven into the plate-shaped workpiece from the opposite side of the perforated nut, through which the portion of the plate-shaped workpiece that abuts against the cylindrical portion of the perforated nut is punched, and the periphery of the punched portion is pressed into the annular groove of the perforated nut and extended, thereby performing perforated nut riveting installation on the plate-shaped workpiece. Existing technical documents

[0004] Patent Document 1: Japanese Patent Publication No. 2014-88936

[0005] However, if the perforated nut is joined to the plate-shaped workpiece (laminated body) in an overlapping state using the joining method described above, the area around the punched portion of the outer plate-shaped workpiece cannot fully extend within the annular groove of the perforated nut (outside the extended portion of the inner plate-shaped workpiece), resulting in a reduction in the bonding force between the outer plate-shaped workpiece and the perforated nut. Furthermore, if the riveting die is forcefully driven in to increase the bonding force between the outer plate-shaped workpiece and the perforated nut (i.e., forceful riveting), the deformed portion resulting from the extension of the outer plate-shaped workpiece will bend or break. Moreover, this tendency is more pronounced the thinner the outer plate-shaped workpiece. Summary of the Invention

[0006] The purpose of this invention is to solve the problems in the existing methods of joining perforated nuts to two overlapping plate-shaped workpieces (laminated bodies), and to provide a joining method that can join perforated nuts to laminated bodies of multiple overlapping plate-shaped workpieces in a manner that exhibits high joining strength (high freewheeling torque (anti-rotational force) and high clamping force (anti-pull-out force)).

[0007] In this invention, the invention described in Invention 1 is a method for joining a perforated nut to a laminate of plate-shaped workpieces, used to join a perforated nut to a laminate of multiple overlapping plate-shaped workpieces. The perforated nut is formed as a flattened cylinder with a central cylindrical portion and an annular cavity around the cylindrical portion. The method for joining the perforated nut to the laminate of plate-shaped workpieces is characterized by having: a first riveting step, in which the perforated nut is positioned such that the opening side of the annular cavity faces one side of a first plate-shaped workpiece, and a nut with a cylindrical front end face is driven into the other side of the first plate-shaped workpiece. A riveting die punches a first plate-shaped workpiece into a circle, and extends the periphery of the punched portion within the annular cavity of the through-hole nut, thereby joining the through-hole nut to the first plate-shaped workpiece; and a second riveting process involves stacking a second plate-shaped workpiece on the other side of the first plate-shaped workpiece to which the through-hole nut was joined in the first riveting process, and then driving a riveting die having a cylindrical front end face into the stacked side of the second plate-shaped workpiece, punching the second plate-shaped workpiece into a circle, and extending the periphery of the punched portion within the annular cavity of the through-hole nut outside the extended portion of the first plate-shaped workpiece.

[0008] The invention described in Invention 2 is based on the invention described in Invention 1, characterized in that the riveting die used in the first riveting process and / or the second riveting process forms the front end side in the shape of a frustum cone.

[0009] The invention described in Invention 3 is based on the invention described in Invention 2, and is characterized in that the angle of inclination of the circumferential surface of the frustum-shaped portion of the riveting die used in the second riveting process relative to the vertical direction is smaller than the angle of inclination of the circumferential surface of the frustum-shaped portion of the riveting die used in the first riveting process relative to the vertical direction.

[0010] The invention described in Invention 4 is based on the invention described in Invention 2 or 3, characterized in that the outer diameter of the front end face of the riveting die used in the second riveting process is smaller than the outer diameter of the front end face of the riveting die used in the first riveting process.

[0011] According to the method for joining a perforated nut to a laminated plate-shaped workpiece as described in Invention 1 (hereinafter referred to as the method for joining a perforated nut), in the second riveting process, the periphery of the punched portion of the second plate-shaped workpiece extends separately outside the extended portion of the first plate-shaped workpiece within the annular cavity of the perforated nut. Therefore, the following situations will not occur: insufficient extension, breakage of the deformed portion caused by extension, or insufficient engagement between the extended portion of the first plate-shaped workpiece and the extended portion of the second plate-shaped workpiece. Therefore, according to the method for joining a perforated nut as described in Invention 1, the perforated nut can be firmly joined to the overlapping first and second plate-shaped workpieces in a manner exhibiting high freewheeling torque and high clamping force.

[0012] According to the joining method of the perforated nut described in Invention 2, the riveting die forms the front end side into a frustum-shaped cone. Therefore, in the first riveting process and the second riveting process, the punched portions of the first plate-shaped workpiece and the second plate-shaped workpiece can be smoothly extended within the annular cavity of the perforated nut without breaking. Thus, the perforated nut can be more firmly joined to the overlapping first plate-shaped workpiece and the second plate-shaped workpiece.

[0013] According to the method for joining the perforated nut described in Invention 3, during the second riveting process, the periphery of the punched portion of the second plate-shaped workpiece can be deeply inserted into the annular cavity of the perforated nut. Therefore, the periphery of the punched portion of the second plate-shaped workpiece can smoothly extend to a sufficient width outside the extended portion of the first plate-shaped workpiece within the annular cavity of the perforated nut. Thus, according to the method for joining the perforated nut described in Invention 3, the perforated nut can be very firmly joined to the overlapping first and second plate-shaped workpieces.

[0014] According to the method for joining the perforated nut described in Invention 4, during the second riveting process, the periphery of the punched portion of the second plate-shaped workpiece can penetrate deeper into the annular cavity of the perforated nut, thus allowing the periphery of the punched portion of the second plate-shaped workpiece to extend very smoothly between itself and the extended portion of the first plate-shaped workpiece. Therefore, according to the method for joining the perforated nut described in Invention 4, the perforated nut can be joined extremely firmly to the overlapping first and second plate-shaped workpieces. Attached Figure Description

[0015] Figure 1 These are explanatory diagrams showing a perforated nut ((a) is a top view, (b) is a sectional view along line AA in (a), (c) is a perspective view, and (d) is a vertical end view of the portion with the annular cavity). Figure 2 This is an explanatory diagram (vertical sectional view) showing the front end of the riveting die ((a) shows the first riveting die, (b) shows the second riveting die). Figure 3 This is an illustration (vertical sectional view) showing the connection between a perforated nut and two overlapping plate-shaped workpieces (a bracket and a washer). Figure 4 This is an explanatory diagram showing the state in which the perforated nut is joined with two overlapping plate-shaped workpieces (a bracket and a washer) (a three-dimensional view of the state after a portion has been removed). Figure 5 This is an enlarged illustration (vertical sectional view) showing the location of the annular cavity of the perforated nut that is coupled with two overlapping plate-shaped workpieces (support and washer). Figure 6This is an explanatory diagram showing a modified example of a perforated nut (vertical sectional view of the location where the annular cavity is installed). Detailed Implementation

[0016] Below, an embodiment of the method for joining the perforated nut according to the present invention will be described in detail with reference to the accompanying drawings.

[0017] <Structure of a perforated nut> Figure 1 This refers to a perforated nut installed on a stack of multiple plate-shaped workpieces. The perforated nut 1 is integrally formed from metal (e.g., iron) into a flat cylindrical shape (cylindrical shape) with a cylindrical screw through hole 2 in the center, and has a specified size (approximately 14.5 mm in diameter × approximately 6.0 mm in height). Furthermore, a threaded groove (not shown) is threaded onto the inner circumferential surface of the screw through hole 2, and tapered surfaces 6a and 6b are formed at the upper and lower edges of the screw through hole 2 for easy threaded connection with a screw (not shown).

[0018] Furthermore, the upper periphery of the screw through hole 2 protrudes upwards more than the other parts, forming a cylindrical portion 3 with a certain thickness. Additionally, an annular cavity 4 with a dovetail-shaped vertical cross-section (a groove wider at the lower end than at the upper end) is formed on the lower outer periphery of this cylindrical portion 3.

[0019] The inner wall surface 4a of the annular cavity 4 is vertical, and the outer inner wall surface 4b is inclined at an angle of about 15° relative to the vertical direction (inclined from the top to the bottom and outward). Furthermore, a horizontal bottom surface 4c of a certain width is formed between the lower end of the inner wall surface 4a and the lower end of the outer inner wall surface 4b.

[0020] Furthermore, multiple rotation-prevention ribs 5, 5… with a horizontal cross-section of a triangular shape are provided at equal intervals on the outer inner wall surface 4b in a vertical manner. In addition, the upper part of the outer peripheral surface of the perforated nut 1 is inclined at an angle of about 15° with respect to the vertical direction (inclined from the top to the bottom and outward) as well as the inner wall surface 4b of the outer side of the annular cavity 4. The part between this inclined surface and the inner wall surface 4b of the outer side of the annular cavity 4 forms the outer cylindrical part 7.

[0021] <Structure of Riveting Die> on the other hand, Figure 2This describes two riveting dies used when joining a perforated nut 1 to a laminated plate-shaped workpiece (riveting installation). The first riveting die 11, used in the first riveting process, is formed of metal (iron) into a cylindrical shape with a central through hole 15, into which the cylindrical portion 3 of the perforated nut 1 is inserted. Furthermore, the inner diameter of the through hole 15 is approximately the same as the outer diameter of the cylindrical portion 3 of the perforated nut 1. Also, the front edge (lower edge) of the first riveting die 11 is approximately a frustum-shaped cone (inverted frustum-shaped) with a smaller diameter than the other portions.

[0022] That is, at a position above a predetermined height from the lower end, the outer peripheral edge of the first riveting die 11 enters the inner side to form a step 16. Furthermore, the lower portion of this step 16 is approximately frustum-shaped with a predetermined height h1, and the lower end face 13 is a horizontal ring (circular shape) of a certain width with a predetermined outer diameter φd1. Additionally, a horizontal ring (circular shape) of a certain width is formed at the base (upper) end of the frustum-shaped portion. Furthermore, the outer peripheral surface of the frustum-shaped portion is a conical surface 12 that slopes inward from the upper side to the lower side, tilting at a predetermined angle θ1 (e.g., 20°) relative to the vertical direction. Furthermore, the outer peripheral edges of the base and front ends of the frustum-shaped portion are chamfered to predetermined radii of curvature Ra and Rb, respectively.

[0023] Furthermore, the second riveting die 11' used in the second riveting process is also formed from the same raw material as the first riveting die 11, and is cylindrical (cylindrical) with a frustum-shaped front edge, but the shape of the frustum-shaped front edge is slightly different from that of the first riveting die 11. That is, the second riveting die 11' can be matched with the thickness of the second plate-shaped workpiece and the shape of the first plate-shaped workpiece extended by the first riveting die 11, so that the height h2 of the frustum-shaped portion is lower than the height h1 of the frustum-shaped portion of the first riveting die 11 by a predetermined height, or the outer diameter φd2 of the lower end face 13 of the frustum-shaped portion is smaller than the outer diameter φd1 of the lower end face 13 of the frustum-shaped portion of the first riveting die 11 by a predetermined diameter. In addition, the second riveting die 11' can make the inclination angle θ2 of the cone surface 12 smaller than the inclination angle θ1 of the cone surface 12 of the first riveting die 11 by a predetermined angle. In addition, the outer peripheral edges of the base end and front end of the frustum-shaped portion of the second riveting die 11' are also chamfered to a specified radius of curvature Ra and Rb, respectively, just like the first riveting die 11.

[0024] <Methods for attaching perforated nuts> Figure 3This illustrates an example of a method for joining two overlapping plate-shaped workpieces (laminated bodies) using the aforementioned perforated nut 1 (an example of joining a 1.2mm thick support W1 and a 0.8mm thick washer W2 with the perforated nut 1). When joining the perforated nut 1 with the two overlapping plate-shaped workpieces W1 and W2, a pressure device such as a crank press is used. Furthermore, as... Figure 3 As shown in (a), the first riveting die 11 is positioned on the pressurizing device with its front edge frustoconical portion located on the lower side. Furthermore, on the lower side of the first riveting die 11, the first plate-shaped workpiece W1 (support) is positioned with its plate surface horizontal. The perforated nut 1 is positioned with its annular cavity 4 opening side facing the lower side of the first plate-shaped workpiece W1, and its cylindrical portion 3 is concentric with the through hole 15 of the first riveting die 11 and fixed in this manner.

[0025] Furthermore, as described above, after the perforated nut 1 is configured to face the first riveting die 11 with respect to the first plate-shaped workpiece W1, as... Figure 3 As shown in (b), the first riveting die 11 is driven into the first plate-shaped workpiece W1 and the through-hole nut 1 from above under a specified pressure. Then, the circular portion of the first plate-shaped workpiece W1 that abuts against the cylindrical portion 3 of the through-hole nut 1 is punched out, and the punched portion (W) is made so that... 1d The surrounding portion of the nut extends within the annular cavity 4 of the perforated nut 1, thereby connecting the perforated nut 1 to the first plate-shaped workpiece W1 (first riveting process).

[0026] As described above, after the perforated nut 1 is joined to the first plate-shaped workpiece W1 through the first riveting process, the first riveting die 11 installed on the pressure device is removed, and the second riveting die 11' is installed in the same position (i.e., the through hole 15' of the second riveting die 11' is configured to be concentric with the cylindrical portion 3 of the perforated nut 1). Then, as... Figure 3 As shown in (c), the second plate-shaped workpiece W2 (washer) is arranged on the upper side of the cylindrical part 3 of the perforated nut 1, which is joined to the first plate-shaped workpiece W1 by the first riveting process, so that the plate surface is horizontal.

[0027] Furthermore, as described above, after the second plate-shaped workpiece W2 is positioned on the upper side of the perforated nut 1, as... Figure 3 As shown in (d), the second riveting die 11' is driven into the second plate-shaped workpiece W2 from above under a specified pressure, punching out the circular portion of the second plate-shaped workpiece W2 that abuts against the cylindrical portion 3 of the through nut 1, and causing the punched portion (W) to... 2d The surrounding portion of the perforated nut 1 is within the annular cavity 4 of the first plate-shaped workpiece W1's extension portion W. 1f The upper part extends, thereby connecting the perforated nut 1 to the second plate-shaped workpiece W2 (second riveting process).

[0028] Figure 4 This is a schematic diagram showing the state after the perforated nut 1 is engaged with the first plate-shaped workpiece W1 (bracket) and the second plate-shaped workpiece W2 (washer). Figure 5 This is a schematic diagram showing the location of the annular cavity 4 of the perforated nut 1. Within the annular cavity 4 of the perforated nut 1, which is coupled to the first plate-shaped workpiece W1 and the second plate-shaped workpiece W2, the area around the punched portion of the first plate-shaped workpiece W1 extends without forming gaps between the inner wall surface 4a on the inner side, the inner wall surface 4b on the outer side, and the bottom surface 4c of the annular cavity 4 (the extended portion W). 1f Furthermore, in the extended portion W of the first plate-shaped workpiece W1... 1f On the upper side, the area around the punched portion of the second plate-shaped workpiece W2 will not break but extend (the extended portion W) 2f Its front end becomes the inner wall surface 4a that reaches the inner side of the annular cavity 4.

[0029] <Effects of the through-nut connection method> The above-mentioned method for joining the perforated nut 1 includes: a first riveting step, in which a first plate-shaped workpiece W1 is punched into a circle, and the periphery of the punched portion extends within the annular cavity 4 of the perforated nut 1, thereby joining the perforated nut 1 with the first plate-shaped workpiece W1; and a second riveting step, in which a second plate-shaped workpiece W2 is punched into a circle, and the periphery of the punched portion extends within the annular cavity 4 of the perforated nut 1 within the extended portion W of the first plate-shaped workpiece W1. 1f The outer side extends. Therefore, according to the above-described joining method of the perforated nut 1, the area around the punched portion of the second plate-shaped workpiece W2 will not be insufficiently extended within the annular cavity 4 of the perforated nut 1, and the extended portion W will not be insufficiently extended. 2f The front end of the fracture, or the extended portion of the first plate-shaped workpiece W1 1f The extension portion W of the second plate-shaped workpiece W2 2f In cases of insufficient engagement, the perforated nut 1 can be securely engaged with the overlapping first plate-shaped workpiece W1 and second plate-shaped workpiece W2 in a manner exhibiting high free-spinning torque and high-pressure tightening.

[0030] Furthermore, in the above-mentioned method of joining the perforated nut 1, both the first riveting die 11 and the second riveting die 11' have their front ends formed into a frustum-shaped cone. Therefore, in the first riveting process and the second riveting process, the punched portions of the first plate-shaped workpiece W1 and the second plate-shaped workpiece W2 can extend smoothly and without gaps within the annular cavity 4 of the perforated nut 1 without breaking around them. Thus, the perforated nut 1 can be more firmly joined to the overlapping first plate-shaped workpiece W1 and the second plate-shaped workpiece W2.

[0031] Furthermore, in the above-described method for joining the perforated nut 1, the inclination angle θ2 of the circumferential surface of the frustoconical portion of the second riveting die 11' relative to the vertical direction is smaller than the inclination angle θ1 of the circumferential surface of the frustoconical portion of the first riveting die 11. In the second riveting process, the periphery of the punched portion of the second plate-shaped workpiece W2 can deeply penetrate into the annular cavity 4 of the perforated nut 1. Therefore, the periphery of the punched portion of the second plate-shaped workpiece W2 can be deeply embedded in the extended portion W of the first plate-shaped workpiece W1. 1f The outer side extends more smoothly in a way that makes it sufficiently wide. Therefore, according to the above-described method of joining the perforated nut 1, the perforated nut 1 can be joined very firmly to the overlapping first plate-shaped workpiece W1 and the second plate-shaped workpiece W2.

[0032] Furthermore, in the above-described method for joining the perforated nut 1, the outer diameter φd2 of the front end face of the second riveting die 11' is smaller than the outer diameter φd1 of the front end face of the first riveting die 11. In the second riveting process, the periphery of the punched portion of the second plate-shaped workpiece W2 enters deeper into the annular cavity 4 of the perforated nut 1. Therefore, the periphery of the punched portion of the second plate-shaped workpiece W2 can be made to extend into the extended portion W of the first plate-shaped workpiece W1. 1f The outer (upper) side extends very smoothly. Therefore, according to the above-described method of joining the perforated nut 1, the perforated nut 1 can be joined to the overlapping first plate-shaped workpiece W1 and the second plate-shaped workpiece W2 with extreme firmness.

[0033] <Example of a modified connection method for perforated nuts> The method of joining the perforated nut of the present invention is not limited to the above embodiments. Without departing from the spirit of the present invention, the material, shape, structure, size and other structures of the plate workpiece, the laminate, the perforated nut and the riveting mold can be appropriately changed as needed.

[0034] For example, the method of joining the perforated nut of the present invention is not limited to the above-described embodiments, in which the riveting die is driven into the plate-shaped workpiece from the upper side. Alternatively, the perforated nut may be provided on the upper side of the plate-shaped workpiece provided on the upper side of the riveting die, and the riveting die may be driven into the fixed perforated nut upwards, or the perforated nut may be driven into the fixed riveting die.

[0035] Furthermore, the assembly method of the perforated nut of the present invention is not limited to the above-described embodiments. The annular cavity of the perforated nut can be a dovetail groove with an inclined inner wall surface on the outer side, or it can be modified as follows: Figure 6 As shown in (a), the dovetail groove shape (i.e., the diameter of the cylindrical portion gradually decreases from the top to the bottom) narrows downwards, as... Figure 6As shown in (b), a dovetail groove is formed by the inner wall surface narrowing downwards (i.e., the diameter of the cylindrical portion gradually decreases from top to bottom) and the outer wall surface widening downwards (in a manner that gradually increases in diameter from top to bottom), such as... Figure 6 As shown in (c), a groove-shaped structure in which the inner wall surface on the inner side is inclined downwards (i.e., the diameter of the cylindrical portion gradually decreases from the top to the bottom) and the inner wall surface on the outer side is inclined downwards (in a manner that gradually decreases the diameter from the top to the bottom).

[0036] Furthermore, the method of joining the perforated nut of the present invention is not limited to the above-described embodiments. The shape of the second riveting die used in the second riveting process is different from the shape of the first riveting die used in the first riveting process. Alternatively, the shape of the second riveting die can be changed to be the same as the shape of the first riveting die.

[0037] Furthermore, the joining method of the perforated nut of the present invention is not limited to the above-described embodiment. Even if the height and angle of the frustum-shaped portion of the second riveting die used in the second riveting process are less than the height and angle of the frustum-shaped portion of the first riveting die used in the first riveting process, it can be modified so that the height and angle of the frustum-shaped portion of the second riveting die are the same as those of the frustum-shaped portion of the first riveting die. Additionally, when the height and angle of the frustum-shaped portion of the second riveting die are greater than those of the frustum-shaped portion of the first riveting die, as described in the above embodiment, the periphery of the punched portion of the second plate-shaped workpiece can penetrate deeper into the annular cavity of the perforated nut. Therefore, it has the advantage that the periphery of the punched portion of the second plate-shaped workpiece can smoothly extend to a sufficient width outside the extended portion of the first plate-shaped workpiece within the annular cavity of the perforated nut, and further (to a sufficient width) the extended portion of the first plate-shaped workpiece can be extended within a range where the second plate-shaped workpiece will not bend or break.

[0038] Furthermore, the method of joining the perforated nut of the present invention is not limited to joining the perforated nut with the overlapping bracket and washer as described in the above embodiments, but can also be applied when joining the perforated nut with a laminate containing various multi-piece (two or more) plate-shaped workpieces.

[0039] Alternatively, when using the perforated nut joining method of the present invention to join a stack of three overlapping plate-shaped workpieces with a perforated nut, the following method can be used as described in the above embodiment: after performing the first riveting process and the second riveting process, a third riveting die with the same or smaller tilt angle as the second riveting die and a narrow front end width is used to perform the third riveting process on the third plate-shaped workpiece. Alternatively, after performing the first riveting process on two overlapping plate-shaped workpieces as the first plate-shaped workpiece and joining them with the perforated nut, another plate-shaped workpiece is stacked on the (two overlapping) first plate-shaped workpiece as the second plate-shaped workpiece, and the second riveting process is performed on the second plate-shaped workpiece.

[0040] Furthermore, when using the perforated nut joining method of the present invention to join a stack of four or more overlapping plate-shaped workpieces, the same applies. A method can be adopted in which each plate-shaped workpiece is joined to the perforated nut by repeatedly performing a riveting process in sequence. Alternatively, after performing a riveting process (first riveting process) on the stack of multiple overlapping plate-shaped workpieces to join the stack with the perforated nut, another plate-shaped workpiece is stacked on the (multiple overlapping) first plate-shaped workpiece as a second plate-shaped workpiece, and a second riveting process is performed on the second plate-shaped workpiece.

[0041] Furthermore, the method of joining the perforated nut of the present invention is not limited to joining the perforated nut with multiple plate-shaped workpieces having the same thickness as in the above embodiments; it can also join the perforated nut with multiple plate-shaped workpieces having different thicknesses. Additionally, when joining the perforated nut with two overlapping plate-shaped workpieces, even if the thickness of the second plate-shaped workpiece is adjusted to 50% to 80% of the thickness of the first plate-shaped workpiece, it has the advantage of higher bonding force between the perforated nut and the laminate. Industrial applicability

[0042] The method for joining the perforated nut of the present invention has the excellent effects described above, and is therefore preferably used as a method for joining the perforated nut to a laminate of multiple overlapping plate-shaped workpieces. Explanation of reference numerals in the attached figures

[0043] 1, 21, 31, 41… Through-hole nuts 2… Screw through hole 3…Cylindrical part 4, 24, 34, 44… Annular cavity section 11…First riveting mold 11'…Second riveting die 12…conical surface

Claims

1. A method for joining a perforated nut to a laminate of plate-shaped workpieces, for joining a perforated nut to a laminate of multiple overlapping plate-shaped workpieces, wherein the perforated nut is formed as a flattened cylinder with a central cylindrical portion and an annular cavity formed around the cylindrical portion, the method for joining the perforated nut to the laminate of plate-shaped workpieces is characterized by having: In the first riveting process, the perforated nut is configured such that the opening side of the annular cavity faces one side of the first plate-shaped workpiece. A first riveting die with a cylindrical front end face is driven into the first plate-shaped workpiece from the other side, punching the first plate-shaped workpiece into a circle. The periphery of the punched portion extends within the annular cavity of the perforated nut, thereby joining the perforated nut to the first plate-shaped workpiece. In the second riveting process, a second plate-shaped workpiece is stacked on the other side of the first plate-shaped workpiece to which the perforated nut was attached in the first riveting process. Then, a second riveting die with a cylindrical front end face and a shape corresponding to the shape of the second plate-shaped workpiece and the shape of the first plate-shaped workpiece after being extended by the first riveting die is driven into the stacked side of the second plate-shaped workpiece. The second plate-shaped workpiece is punched into a circle, and the periphery of the punched portion extends outside the extended portion of the first plate-shaped workpiece within the annular cavity of the perforated nut.

2. The method for joining a perforated nut to a plate-shaped workpiece laminate according to claim 1, characterized in that, The riveting die used in the first riveting process and / or the second riveting process forms the front end side into a frustum-shaped cone.

3. The method for joining a perforated nut to a plate-shaped workpiece laminate according to claim 2, characterized in that, The angle of inclination of the circumferential surface of the frustoconical portion of the riveting die used in the second riveting process relative to the vertical direction is smaller than the angle of inclination of the circumferential surface of the frustoconical portion of the riveting die used in the first riveting process relative to the vertical direction.

4. The method for joining a perforated nut to a plate-shaped workpiece laminate according to claim 2 or 3, characterized in that, The outer diameter of the front end face of the riveting die used in the second riveting process is smaller than the outer diameter of the front end face of the riveting die used in the first riveting process.

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