CN115673201A - Method for forming rivet nut, intermediate piece, forming device and rivet nut - Google Patents
Method for forming rivet nut, intermediate piece, forming device and rivet nut Download PDFInfo
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- CN115673201A CN115673201A CN202211505035.1A CN202211505035A CN115673201A CN 115673201 A CN115673201 A CN 115673201A CN 202211505035 A CN202211505035 A CN 202211505035A CN 115673201 A CN115673201 A CN 115673201A
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Abstract
The invention provides a forming method, an intermediate piece, a forming device and a rivet nut, which comprises the steps of upsetting and shaping a preset blank twice to form a second preset blank; forming a second preset blank into a preset flange, a preset rod part and a head fixed point in the preset flange; reversely extruding the first hole section of the first blind hole through the fixed point of the head; reversely extruding a second blind hole from one end of the preset rod part, which deviates from the preset flange, and impact extruding the first blind hole to form a second hole section connected below the first hole section, wherein the aperture of the second blind hole is gradually reduced from one end of the preset rod part, which deviates from the preset flange, towards the preset flange, and the diameter of the bottom of the second blind hole is smaller than that of the first hole section and larger than that of the second hole section; finishing the preset flange and the preset rod part to obtain an intermediate part of the rivet nut; separating the waste material positioned between the first blind hole and the second blind hole from the intermediate piece of the rivet nut so as to communicate the first blind hole with the second blind hole and obtain a second inner hole and a third inner hole; and carrying out necessary treatment to obtain a finished product.
Description
Technical Field
The invention belongs to the field of fastener forming, and particularly relates to a forming method, an intermediate piece, a forming device and a blind rivet nut.
Background
The rivet nut, also called as a rivet cap, is a nut which is fastened with a connected piece in a rivet form, and is widely applied to the assembly of electromechanical and light industrial products such as automobiles, aviation, instruments, furniture, decoration and the like. The novel riveting tool is developed for overcoming the defects that a welding nut of a metal sheet and a thin pipe is easy to melt, an internal thread is easy to slip, and the like, does not need to tap the internal thread, does not need to weld the nut, is firm in riveting, is high in efficiency, and is convenient to use. However, in the method for forming the blind rivet nut, part of the waste materials need to be punched to form an axial inner hole of the blind rivet nut, and then the inner hole is tapped to form threads, corresponding blind holes are formed at two ends of the nut before the waste material punching process, the blind hole end with a larger hole diameter is used for punching, so that hole waste materials are blanked from the blind hole end with a smaller hole diameter, and therefore the corresponding blind holes are communicated to form the axial inner hole of the blind rivet nut, but burrs and steps are easily remained at the torn part after the waste materials are punched, or due to the reason that the preorder extrudes the blind hole with a smaller hole diameter, a lamination is formed on the hole wall of the axial inner hole after the waste materials are punched, so that burrs are generated after the axial inner hole is tapped subsequently, and the product is poor.
Disclosure of Invention
In view of the problems in the prior art, a primary object of the present invention is to provide a method, an intermediate member, a forming apparatus, and a blind nut for forming a blind nut, in which the intermediate member formed by six dies of a preset blank by a multi-station cold heading forming machine includes a rod portion and a head flange fixedly connected to one end of the rod portion, the head flange is recessed from one end of the rod portion, the first blind hole is recessed from the other end of the rod portion, the second blind hole is recessed from the other end of the rod portion, the diameter of the second blind hole is gradually reduced from the other end of the rod portion, the diameter of the bottom of the second blind hole is larger than the diameter of the second blind hole, and smaller than the diameter of the first blind hole, and when a method for punching waste material from the first blind hole to the second blind hole is performed, impact of the waste material on the second blind hole by the hole can be completely avoided, so that no residual burr or step is left at the torn portion, the torn surface is smooth and has no lamination, thereby ensuring no burr after tapping and ensuring a good product quality.
The purpose of the invention is realized by the following technical scheme:
the invention provides a method for forming a blind rivet nut, which comprises a rod part and a head flange fixedly connected to one end of the rod part, wherein the blind rivet nut is provided with an inner hole penetrating through the head flange and the rod part along the axial direction of the blind rivet nut, the inner hole at least comprises a first inner hole, a second inner hole and a third inner hole which are sequentially communicated, the aperture of the third inner hole is gradually reduced from one end of the rod part departing from the head flange to the head flange, and the apertures of the second inner hole and the third inner hole are smaller than that of the first inner hole, and the method comprises the following steps:
cutting the wire to form a preset blank;
upsetting and shaping the preset blank to form a first preset blank;
upsetting and shaping the first preset blank to form a second preset blank;
forming a preset flange and a preset rod part from the second preset blank, and forming a head fixed point in the preset flange;
reversely extruding a first hole section of a first blind hole from the inside of the preset flange through the head fixed point to obtain a first inner hole;
reversely extruding the preset rod part from one end of the preset rod part, which is deviated from the preset flange, out of a second blind hole, and impact-extruding the first blind hole to form a second hole section connected below the first hole section; wherein the content of the first and second substances,
the aperture of the second blind hole is gradually reduced from one end, deviating from the preset flange, of the preset rod part to the preset flange; the diameter of the bottom of the second blind hole is smaller than the diameter of the first hole section; the diameter of the second hole section is smaller than that of the hole bottom of the second blind hole;
finishing the preset flange and the preset rod part to form the head flange and the rod part to obtain an intermediate piece of the rivet nut;
separating the waste material positioned between the first blind hole and the second blind hole from the intermediate piece of the rivet nut so as to communicate the first blind hole with the second blind hole and obtain a second inner hole and a third inner hole;
and carrying out heat treatment, tapping and electroplating on the preset blind rivet nut with the second inner hole and the third inner hole to obtain a finished blind rivet nut.
The invention also provides a middleware of the rivet nut, which comprises:
the body comprises a rod part and a head flange fixedly connected to one end of the rod part; the body is concentrically provided with a first blind hole and a second blind hole along the axial direction of the body, the first blind hole is formed by inwards sinking the end face of the head flange departing from the rod part, and the second blind hole is formed by inwards sinking the end face of the rod part departing from the head flange; wherein the content of the first and second substances,
the first blind hole at least comprises a first hole section and a second hole section, and the second hole section is positioned between the first hole section and the second blind hole in the axial direction of the body;
the hole diameter of the second blind hole is gradually reduced from one end, away from the head flange, of the rod part to the head flange;
the diameter of the bottom of the second blind hole is smaller than the aperture of the first hole section and larger than the aperture of the second hole section.
As a further description of the above technical solution, the diameter of the bottom of the second blind hole is 1.0mm-2.0mm larger than the diameter of the second hole section.
As a further description of the above technical solution, an included angle formed between the hole wall of the second blind hole and the axis of the body is 10 ° to 60 °.
As further described in the above technical solution, the depth of the second blind hole is 0.1mm-3.0mm.
As a further elaboration of the above solution, the aperture of the second bore section is 0.1mm-2.0mm larger than the nominal diameter of the thread.
The invention also provides a forming device of the rivet nut, which comprises a cold header and a die assembly arranged on the cold header, wherein the die assembly comprises:
the first die is used for upsetting and shaping the preset blank to form a first preset blank;
the second die is used for upsetting and shaping a second preset blank to form the second preset blank;
a third die for forming the second preset blank into a preset flange and a preset rod part, and forming a head fixed point in the preset flange;
the fourth die is used for reversely extruding a first hole section of the first blind hole from the preset flange through the head fixed point to obtain a first inner hole;
the fifth die is used for enabling the preset rod part to reversely extrude out of a second blind hole from one end, away from the preset flange, of the preset rod part and enabling the first hole section to inwards extend to form a second hole section; wherein, the first and the second end of the pipe are connected with each other,
the aperture of the second blind hole is gradually reduced from one end, deviating from the preset flange, of the preset rod part to the preset flange; the diameter of the bottom of the second blind hole is smaller than the diameter of the first hole section; the diameter of the second hole section is smaller than that of the hole bottom of the second blind hole;
the sixth die is used for finishing the preset flange and the preset rod part to form the head flange and the rod part to obtain an intermediate piece of the blind rivet nut;
and the seventh die is used for separating the waste material between the first blind hole and the second blind hole from the intermediate piece of the rivet nut, so that the first blind hole is communicated with the second blind hole to obtain a second inner hole and a third inner hole.
As a further description of the above technical solution, the first mold, the second mold, the third mold, the fourth mold, the fifth mold, the sixth mold, and the seventh mold each include a main mold and a punch die provided corresponding to the main mold.
The invention also provides a rivet nut, which comprises a rod part and a head flange fixedly connected to one end of the rod part, wherein the rivet nut is provided with an inner hole which penetrates through the head flange and the rod part along the axis direction of the rivet nut, the inner hole at least comprises a first inner hole, a second inner hole and a third inner hole, the first inner hole penetrates through the head flange and the rod part, and the second inner hole is connected between the first inner hole and the third inner hole; wherein the content of the first and second substances,
the aperture of the third inner hole is gradually reduced from one end of the rod part, which is far away from the head flange, to the head flange;
the aperture of the second inner hole and the aperture of the third inner hole are both smaller than the aperture of the first inner hole.
As a further description of the above technical solution, the hole wall of the second inner hole is formed with a thread; and a chamfer is formed at one end of the rod part, which is far away from the head flange.
In summary, the outstanding effects of the invention are as follows:
in the method for forming the blind rivet nut, an intermediate piece formed by punching six dies of a preset blank by a multi-station cold heading forming machine comprises a rod part and a head flange fixedly connected to one end of the rod part, a first blind hole is formed in the end, away from the rod part, of the head flange, a second blind hole is formed in the end, away from the head flange, of the rod part, the aperture of the second blind hole is gradually reduced from the end, away from the head flange, of the rod part to the head flange, the diameter of the bottom of the second blind hole is larger than that of a second hole section of the first blind hole and smaller than that of a first hole section of the first blind hole, waste materials between the first blind hole and the second blind hole are separated from the intermediate piece of the blind rivet nut through a seventh die of the multi-station cold heading machine, the first blind hole is communicated with the second blind hole, the preset blind rivet nut formed with the second inner hole and a third inner hole is obtained, the aperture of the second hole section is used as a reference for punching the waste materials, the blanking track of the second blind hole is completely, burrs are not remained at a tearing position after punching, smooth surfaces of the preset rivet nut are guaranteed, and the lamination quality of a product is guaranteed, and the lamination quality of the product is guaranteed.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments or the prior art descriptions will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is also possible for those skilled in the art to obtain other drawings based on the drawings without creative efforts.
FIG. 1 is a schematic structural view of an intermediate member of a blind rivet nut according to an embodiment of the present invention;
FIG. 2 is a finished view of a blind rivet nut in accordance with an embodiment of the present invention;
FIG. 3 is a schematic view of a blind rivet nut being scrapped by a seventh die according to an embodiment of the present invention;
FIG. 4 is a schematic partial structural view of a forming device for a blind rivet nut according to an embodiment of the present invention;
the reference numbers illustrate:
1. a body; 11. a rod portion; 12. a head flange; 13. a first blind hole; 131. a first bore section; 132. a second bore section; 14. a second blind hole; 15. waste materials; 21. a first inner bore; 22. a second inner bore; 23. a third inner bore; 24. chamfering; 3. a sixth mold; 4. a seventh mold; 5. performing master molding; 51. a main model cavity; 52. a main die punch 6 and a die; 61. upsetting a flange punch; 62. a hole-protecting punch; 63. and punching the waste punch.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without making any creative effort based on the embodiments in the present invention, belong to the protection scope of the present invention.
In the description of the present invention, it should be noted that the terms "upper", "middle", "lower", "inside", "outside", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the referred device or component must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. The specific meanings of the above terms in the present invention can be understood in a specific case to those of ordinary skill in the art.
The following description will be made with reference to fig. 1 to 4 and the embodiments.
The embodiment provides a forming method of a blind rivet nut, the blind rivet nut includes a rod portion 11 and a head flange 12 fixedly connected to one end of the rod portion 11, the blind rivet nut is provided with an inner hole penetrating through the head flange 12 and the rod portion 11 along an axial direction thereof, the inner hole at least includes a first inner hole 21, a second inner hole 22 and a third inner hole 23 which are sequentially communicated, the aperture of the third inner hole 23 is gradually reduced from one end of the rod portion 11 deviating from the head flange 12 toward the head flange 12, and the apertures of the second inner hole 22 and the third inner hole 23 are smaller than the aperture of the first inner hole 21, the forming method includes the following steps:
cutting the wire to form a preset blank;
upsetting and shaping the preset blank to form a first preset blank;
upsetting and shaping the first preset blank to form a second preset blank;
forming a preset flange and a preset rod part from the second preset blank, and forming a head fixed point in the preset flange;
reversely extruding the preset flange through the head at a fixed point to form a first hole section 131 of the first blind hole 13 shown in fig. 1, so as to obtain the first inner hole 21;
reversely extruding the preset rod part from one end of the preset rod part, which is far away from the preset flange, out of a second blind hole 14 shown in fig. 1, and impact-extruding the first blind hole 13 to form a second hole section 132 connected below the first hole section 131; wherein the content of the first and second substances,
the aperture of the second blind hole 14 is gradually reduced from one end of the preset rod part departing from the preset flange to the preset flange; the diameter of the bottom of the second blind hole 14 is smaller than the diameter of the first hole section 131; the diameter of the second hole section 132 is smaller than the diameter of the hole bottom of the second blind hole 14;
finishing the preset flange and the preset rod part to form the head flange 12 and the rod part 11 to obtain an intermediate piece of the rivet nut;
as shown in fig. 3, separating the waste material 15 between the first blind hole 13 and the second blind hole 14 from the intermediate piece of the blind rivet nut, so that the first blind hole 13 is communicated with the second blind hole 14, and obtaining a second inner hole 22 and a third inner hole 23;
and carrying out heat treatment, tapping and electroplating on the preset blind rivet nut with the second inner hole 22 and the third inner hole 23 to obtain a finished blind rivet nut.
By means of the method, a multi-station cold heading forming machine is used for processing, seven-die seven-punch is carried out on the preset blank, and the preset blank formed by cutting wires is subjected to upsetting and shaping twice through a first die and a second die; then, forming a preset flange, a preset rod part and a head fixed point in the preset flange through a third die; then, a fourth die is utilized to perform backward extrusion through a fixed point of the head portion to form a first hole section 131 of the first blind hole 13, so that a first inner hole 21 of the rivet nut is obtained, and the first inner hole 21 extends into the preset rod portion from the end face, far away from the preset rod portion, of the preset flange; the fifth die can reduce the backward extrusion aperture of the end of the preset rod part departing from the preset flange from the end of the preset rod part departing from the preset flange toward the second tapered blind hole 14 of the preset flange, and simultaneously, the first blind hole 13 extends inwards to form a second hole section 132 connected to the lower part of the first hole section 131, wherein the diameter of the bottom of the second blind hole 14 is smaller than the aperture of the first hole section 131 but larger than the aperture of the second hole section 132, so that the hole wall of the second blind hole is completely prevented from the blanking track of the waste 15 in the subsequent waste 15 punching process, and the product yield after the waste 15 punching is ensured. The sixth die 3 will finish the blank formed with the second blind hole 14, mainly finishing the preset flange and the preset rod part, including the outer diameter and the joint of the preset flange and the preset rod part, so as to form the head part and the rod part 11 with various parameters meeting the finished product standard, i.e. obtaining the intermediate piece of the blind rivet nut with preset parameter values; separating the waste material 15 between the first blind hole 13 and the second blind hole 14 from the intermediate piece of the blind rivet nut by using a seventh die 4, communicating the first blind hole 13 with the second blind hole 14 to obtain a preset blind rivet nut formed with a second inner hole 22 and a third inner hole 23, and performing necessary processes of heat treatment, tapping, electroplating and the like on the preset blind rivet nut obtained by cold heading to obtain a finished blind rivet nut, wherein the tapping is to tap the second inner hole 22; in addition, when the seventh mold 4 is processed, the scraps 15 drive the product blank at the periphery of the seventh mold to flow downwards to a certain extent due to the flowing characteristic of the metal, and the product blank at the periphery of the second blind hole 14 is arranged in a non-straight section, so that the product blank forms a certain angle with the axis of the product blank, and the length ratio between the second hole section 132 of the first blind hole 13 and the scraps 15 can be comprehensively considered and arranged according to the nominal diameter of the thread to be formed subsequently, the flowing characteristic of the metal, the forming force of the scraps 15, and other factors, so that the flowing angle is smaller than or equal to the angle of the thread to be formed. For example, in this embodiment, the flow is angled at less than the 60 thread angle to be formed.
Specifically, this implementation provides a rivet nut's middleware includes:
the body 1 comprises a rod part 11 and a head flange 12 fixedly connected to one end of the rod part 11; the body 1 is concentrically provided with a first blind hole 13 and a second blind hole 14 along the axial direction, the first blind hole 13 is formed by inwards recessing the end face of the head flange 12 departing from the rod part 11, and the second blind hole 14 is formed by inwards recessing the end face of the rod part 11 departing from the head flange 12; wherein the content of the first and second substances,
the first blind hole 13 comprises at least a first hole section 131 and a second hole section 132, and the second hole section 132 is located between the first hole section 131 and the second blind hole 14 in the axial direction of the body 1;
the bore diameter of the second blind hole 14 is tapered from the end of the shaft 11 facing away from the head flange 12 toward the head flange 12;
the diameter of the bottom of the second blind hole 14 is smaller than the diameter of the first hole section 131 and larger than the diameter of the second hole section 132.
By means of the structure, in the process that the waste 15 between the first blind hole 13 and the second blind hole 14 is punched and blanked from one end of the head flange 12, the first blind hole 13 and the second blind hole 14 are communicated to form an inner hole of the rivet nut, the waste 15 is gradually separated from the body 1, the second blind hole 14 falls into a waste 15 mold core arranged in the main mold 5, the diameter of the second blind hole 14 gradually decreases from one end of the preset rod part deviating from the head flange 12 to the head flange 12, the diameter of the bottom of the hole is smaller than that of the first hole section 131 but larger than that of the second hole section 132, the waste 15 is punched by taking the diameter of the second hole section 132 as a reference, the blanking track of the waste 15 is completely avoided by the hole wall of the second blind hole 14, so that burrs or steps cannot be left at the punched tearing part, smooth and lamination-free tearing surfaces are ensured, burrs after tapping are avoided, the product quality is controllable, and the product yield is ensured.
Specifically, in this embodiment, the diameter of the bottom of the second blind hole 14 is 1.5mm larger than the diameter of the second hole section 132, and enough radial gaps are reserved to ensure that the inner wall of the second blind hole is not on the blanking track of the waste material 15, so that the blanking process is smooth, no residual burr or step is left at the final torn part, and the whole torn surface is smooth and has no lamination.
Specifically, in this embodiment, an included angle formed by the hole wall of the second blind hole 14 and the axis of the body 1 is 20 °, the depth of the second blind hole 14 is 0.9mm, so as to adapt to subsequent tapping specifications, and certainly, in other embodiments, according to actual production requirements, the included angle formed by the hole wall of the second blind hole 14 and the axis of the body 1 may also be set to any value between 10 ° and 60 °, and the depth of the second blind hole 14 may also be set to any value between 0.1mm and 3.0mm.
Specifically, in this embodiment, the second hole section 132 is subsequently tapped to form a thread, and the aperture of the second hole section 132 is 0.5mm larger than the nominal diameter of the thread to be formed subsequently, but in other embodiments, the aperture of the second hole section 132 may also be set to be 0.1mm to 2.0mm larger than the nominal diameter of the thread to be formed subsequently according to actual needs.
Specifically, in this embodiment, the forming device for the blind rivet nut includes a cold heading machine (not shown in the figure), and a mold assembly (not shown in the figure) installed on the cold heading machine, where the mold assembly includes:
the first die is used for upsetting and shaping the preset blank to form a first preset blank;
the second die is used for upsetting and shaping a second preset blank to form the second preset blank;
a third die for forming the second preset blank into a preset flange and a preset rod part, and forming a head fixed point in the preset flange;
a fourth die, configured to enable the inside of the preset flange to reversely extrude the first hole segment 131 of the first blind hole 13 through the fixed point of the head portion, so as to obtain a first inner hole 21;
a fifth die, configured to extrude the preset rod back out of the second blind hole 14 from an end of the preset rod away from the preset flange, and extend the first hole segment 131 inward to form a second hole segment 132; wherein the content of the first and second substances,
the aperture of the second blind hole 14 is gradually reduced from one end of the preset rod part departing from the preset flange to the preset flange; the diameter of the bottom of the second blind hole 14 is smaller than the diameter of the first hole section 131; the diameter of the second hole section 132 is smaller than the diameter of the hole bottom of the second blind hole 14;
a sixth die 3, wherein the sixth die 3 is used for finishing the preset flange and the preset rod to form the head flange 12 and the rod 11, so as to obtain an intermediate piece of the blind rivet nut;
and the seventh die 4 is used for separating the scrap 15 positioned between the first blind hole 13 and the second blind hole 14 from the intermediate piece of the blind rivet nut, so that the first blind hole 13 is communicated with the second blind hole 14 to obtain a second inner hole 22 and a third inner hole 23. It should be understood that, in the present embodiment, the forming device further includes a shearing mechanism (not shown) for shearing the wire into the predetermined billet, and a feeding mechanism (not shown) for moving the feeding between the plurality of dies.
Specifically, in this embodiment, each of the first mold, the second mold, the third mold, the fourth mold, the fifth mold, the sixth mold 3, and the seventh mold 4 includes a main mold 5 and a punch 6 provided corresponding to the main mold 5. Referring to fig. 4, in the present embodiment, the right side is a sixth die 3, the left side is a seventh die 4, wherein the die 6 of the sixth die 3 includes an upsetting flange punch 61 and a hole-protecting punch 62 connected to the upsetting flange punch 61, the main die 5 includes a main die punch 52 located in a main die cavity 51, the main die punch 52 is opposite to the hole-protecting punch 62 and respectively protects the second blind hole 14 and the first blind hole 13, so that the pre-set flange and the pre-set rod portion are finished under the cooperation of the main die cavity 51 and the upsetting flange punch 61, and after the intermediate piece of the blind rivet nut is obtained, the die 6 of the seventh die 4 includes a slug punch 63 that punches down from the opening of the first blind hole 13 to separate the slug 15 located between the first blind hole 13 and the second blind hole 14 from the intermediate piece of the rivet nut, so that the first blind hole 13 and the second blind hole 14 are communicated with each other, and the second inner hole 22 and the third inner hole 23 of the rivet nut are obtained.
Referring to fig. 2, specifically, the blind rivet nut provided in this embodiment includes a rod portion 11 and a head flange 12 fixedly connected to one end of the rod portion 11, the blind rivet nut is provided with inner holes penetrating through the head flange 12 and the rod portion 11 along an axial direction thereof, the inner holes at least include a first inner hole 21, a second inner hole 22 and a third inner hole 23, the first inner hole 21 penetrates through the head flange 12 and the rod portion 11, and the second inner hole 22 is connected between the first inner hole 21 and the third inner hole 23; wherein the bore diameter of the third inner bore 23 tapers from the end of the shaft 11 facing away from the head flange 12 toward the head flange 12; the diameters of the second inner hole 22 and the third inner hole 23 are smaller than the diameter of the first inner hole 21, and the hole wall of the second inner hole 22 adopts threads formed by a tapping method; the end of the stem portion 11 remote from the head flange 12 is also formed with a chamfer 24.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments or substitute equivalent technical features, and any changes, equivalents, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The utility model provides a forming method of rivet nut, rivet nut includes pole portion and fixed connection in the head flange of pole portion one end, rivet nut is equipped with and link up along its axis direction the hole of head flange and pole portion, the hole is at least including first hole, second hole and the third hole that communicates in order, the aperture of third hole certainly pole portion deviates from the one end orientation of head flange the head flange convergent, just the aperture of second hole and third hole all is less than the aperture of first hole, its characterized in that includes the following step:
cutting the wire to form a preset blank;
upsetting and shaping the preset blank to form a first preset blank;
upsetting and shaping the first preset blank to form a second preset blank;
forming the second preset blank into a preset flange and a preset rod part, and forming a head fixed point in the preset flange;
reversely extruding a first hole section of a first blind hole from the inside of the preset flange through the head fixed point to obtain a first inner hole;
reversely extruding the preset rod part from one end of the preset rod part, which is deviated from the preset flange, out of a second blind hole, and impact-extruding the first blind hole to form a second hole section connected below the first hole section; wherein the content of the first and second substances,
the aperture of the second blind hole is gradually reduced from one end, deviating from the preset flange, of the preset rod part to the preset flange; the diameter of the bottom of the second blind hole is smaller than the diameter of the first hole section; the diameter of the second hole section is smaller than that of the hole bottom of the second blind hole;
finishing the preset flange and the preset rod part to form the head flange and the rod part to obtain an intermediate piece of the rivet nut;
separating the waste material positioned between the first blind hole and the second blind hole from the intermediate piece of the rivet nut so as to communicate the first blind hole with the second blind hole and obtain a second inner hole and a third inner hole;
and carrying out heat treatment, tapping and electroplating on the preset blind rivet nut with the second inner hole and the third inner hole to obtain a finished blind rivet nut.
2. An intermediate piece for a blind rivet nut, comprising:
the body comprises a rod part and a head flange fixedly connected to one end of the rod part; the body is concentrically provided with a first blind hole and a second blind hole along the axial direction of the body, the first blind hole is formed by inwards sinking the end face of the head flange departing from the rod part, and the second blind hole is formed by inwards sinking the end face of the rod part departing from the head flange; wherein the content of the first and second substances,
the first blind hole at least comprises a first hole section and a second hole section, and the second hole section is positioned between the first hole section and the second blind hole in the axial direction of the body;
the hole diameter of the second blind hole is gradually reduced from one end, away from the head flange, of the rod part to the head flange;
the diameter of the bottom of the second blind hole is smaller than the aperture of the first hole section and larger than the aperture of the second hole section.
3. The intermediate piece of a blind rivet nut of claim 2, wherein the diameter of the bottom of the second blind bore is 1.0mm to 2.0mm larger than the diameter of the second bore section.
4. An intermediate piece for a blind rivet nut according to claim 3, in which the wall of the second blind bore is at an angle of between 10 ° and 60 ° to the axis of the body.
5. The intermediate piece of a blind clinch nut of claim 2, wherein the second blind hole has a depth of 0.1mm to 3.0mm.
6. The intermediate piece of a blind rivet nut of claim 2, wherein the second bore section has a bore diameter that is 0.1mm to 2.0mm larger than the nominal diameter of the threads.
7. The utility model provides a forming device of rivet nut, its characterized in that, includes the cold heading machine, and install in mould subassembly on the cold heading machine, its characterized in that, mould subassembly includes:
the first die is used for upsetting and shaping the preset blank to form a first preset blank;
the second die is used for upsetting and shaping a second preset blank to form the second preset blank;
a third die for forming the second preset blank into a preset flange and a preset rod part, and forming a head fixed point in the preset flange;
the fourth die is used for reversely extruding a first hole section of the first blind hole from the preset flange through the head fixed point to obtain a first inner hole;
the fifth die is used for enabling the preset rod part to reversely extrude out of the second blind hole from one end, away from the preset flange, of the preset rod part and enabling the first hole section to inwards extend to form a second hole section; wherein, the first and the second end of the pipe are connected with each other,
the aperture of the second blind hole is gradually reduced from one end, deviating from the preset flange, of the preset rod part to the preset flange; the diameter of the bottom of the second blind hole is smaller than the diameter of the first hole section; the diameter of the second hole section is smaller than that of the hole bottom of the second blind hole;
a sixth die, wherein the sixth die is used for finishing the preset flange and the preset rod part to form the head flange and the rod part, so as to obtain an intermediate piece of the blind rivet nut;
and the seventh die is used for separating the waste material between the first blind hole and the second blind hole from the intermediate piece of the rivet nut, so that the first blind hole is communicated with the second blind hole to obtain a second inner hole and a third inner hole.
8. The apparatus for forming a blind rivet nut as defined in claim 7, wherein each of the first mold, the second mold, the third mold, the fourth mold, the fifth mold, the sixth mold, and the seventh mold includes a master mold and a punch die provided in correspondence with the master mold.
9. A rivet nut is characterized by comprising a rod part and a head flange fixedly connected to one end of the rod part, wherein the rivet nut is provided with an inner hole which penetrates through the head flange and the rod part along the axis direction of the rivet nut, the inner hole at least comprises a first inner hole, a second inner hole and a third inner hole, the first inner hole penetrates through the head flange and the rod part, and the second inner hole is connected between the first inner hole and the third inner hole; wherein the content of the first and second substances,
the aperture of the third inner hole is gradually reduced from one end of the rod part, which is far away from the head flange, to the head flange;
the aperture of the second inner hole and the aperture of the third inner hole are both smaller than the aperture of the first inner hole.
10. The blind rivet nut of claim 9, wherein the bore wall of the second bore is threaded; and a chamfer is formed at one end of the rod part, which is far away from the head flange.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211505035.1A CN115673201A (en) | 2022-11-29 | 2022-11-29 | Method for forming rivet nut, intermediate piece, forming device and rivet nut |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211505035.1A CN115673201A (en) | 2022-11-29 | 2022-11-29 | Method for forming rivet nut, intermediate piece, forming device and rivet nut |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115673201A true CN115673201A (en) | 2023-02-03 |
Family
ID=85055811
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211505035.1A Pending CN115673201A (en) | 2022-11-29 | 2022-11-29 | Method for forming rivet nut, intermediate piece, forming device and rivet nut |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115673201A (en) |
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2022
- 2022-11-29 CN CN202211505035.1A patent/CN115673201A/en active Pending
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