Forming method of special-shaped pressure riveted sleeve, special-shaped pressure riveted sleeve and device for forming special-shaped pressure riveted sleeve

Abstract

The invention discloses a forming method of a special-shaped riveted sleeve, which comprises the following steps: a punching die is abutted against the end face of a wire material, and the wire material is cold-forged from top to bottom to form a flange part and a rod part; a through hole is punched from bottom to top from the end of the rod part away from the flange part, wherein a chamfered part is provided at the bottom of the through hole, and the inner diameter of the chamfered part gradually increases toward the bottom end of the rod part; stamping is performed from the end face of the flange part, and the chamfered part flows radially under the action of the punching die, so that the diameter of the bottom end of the rod part gradually increases toward the side away from the flange part to form a bell mouth part; the wire material formed with the flange part, the rod part and the bell mouth part is electroplated to form a riveted sleeve. A one-time cold-forging forming process is adopted, so that the rod part of the front station is formed into a structure of the chamfered part, and then the chamfered part flows radially through the action of the punching die of the rear station, and gradually deforms so that the bottom of the rod part forms a bell mouth part, which greatly improves the production efficiency, reduces the production cost, and shortens the production cycle.

Description

Technical Field

[0001] The invention relates to the technical field of fastener manufacturing, and in particular to a method for forming a special-shaped pressure-riveted sleeve, a special-shaped pressure-riveted sleeve and a device for forming the special-shaped pressure-riveted sleeve. Background Art

[0002] The self-riveted sleeve is fastened to the connected parts by self-riveting, and is widely used on automobile bumpers. The self-riveted nut has the characteristics of a small diameter in the middle rod and a bell-shaped end of the rod, and is often processed by cold heading. According to the traditional cold heading process, the bell-shaped shape of the self-riveted sleeve cannot be formed, and it is necessary to use machining to obtain the bell-shaped mouth of the mouth. The processing and forming process is relatively complicated, resulting in low production efficiency and a longer production cycle, which is not suitable for large-scale production and use; and because of the use of machining, the production cost becomes higher, the quality of the self-riveted sleeve produced is unstable, and the product qualification rate is low. Summary of the invention

[0003] In order to overcome the defects in the prior art, the embodiments of the present invention provide a method for forming a special-shaped self-riveting sleeve, a special-shaped self-riveting sleeve and a device for forming a special-shaped self-riveting sleeve, which are used to solve the problems of complex processing technology, low production efficiency, high cost and low pass rate.

[0004] The embodiment of the present application discloses a forming method of a special-shaped self-riveting sleeve, a special-shaped self-riveting sleeve and a device for forming a special-shaped self-riveting sleeve, which adopts a one-time cold heading forming process to overcome the traditional forming process combining cold heading with machining, and for the problem that products with a small middle diameter and a large end diameter cannot be demolded, the inherent idea is abandoned, and the structure of the front station rod portion being formed into a chamfered portion is adopted, so that the metal strength of the chamfered portion becomes low, which is convenient for stamping and forming, and then through the action of the back station die, the chamfered portion flows radially and gradually deforms so that the bottom of the rod portion is formed into a bell mouth portion. The use of this process greatly improves production efficiency, reduces production costs, shortens production cycles, and improves quality stability.

[0005] Among them, a forming method of a special-shaped riveted sleeve includes the following steps:

[0006] The punching die abuts against the end surface of the wire material and performs cold heading on the wire material from top to bottom to form a flange portion and a rod portion connected to the bottom of the flange portion;

[0007] A through hole penetrating the rod and the flange is punched from bottom to top from one end of the rod away from the flange, wherein a chamfered portion is provided at the bottom of the through hole, and the inner diameter of the chamfered portion gradually increases toward the bottom end of the rod;

[0008] Punching is performed from the end surface of the flange portion, and the chamfered portion flows radially under the action of the punching die, so that the diameter of the bottom end of the rod portion gradually increases toward the side away from the flange portion, forming a bell mouth portion;

[0009] The wire material formed with a flange portion, a stem portion and a bell mouth portion is electroplated to form a riveted sleeve.

[0010] Furthermore, in the step of "the punching die is abutted against the end surface of the wire material, and the wire material is cold headed from top to bottom to form a flange portion and a rod portion connected to the bottom of the flange portion", the following steps are included:

[0011] Cutting the wire and clamping it into the first mold cavity, and flattening the two opposite end surfaces of the wire by a first punching die;

[0012] The flattened wire is clamped into the second main die cavity, and the second die ejector is punched from top to bottom to increase the diameter of the rod;

[0013] The wire is clamped into the third main die cavity, and the third punch ejector punches the preformed flange portion from top to bottom from the end surface of the wire;

[0014] The wire is clamped into the fourth main die cavity, and the fourth punch ejector continues to punch from top to bottom to form the flange portion.

[0015] Furthermore, the maximum diameter of the chamfered portion is consistent with the diameter of the rod portion.

[0016] Furthermore, the minimum inner diameter of the bell-mouth portion is consistent with the outer diameter of the rod portion, and the maximum inner diameter of the bell-mouth portion is greater than the outer diameter of the rod portion.

[0017] The present application also discloses a special-shaped pressure riveted sleeve, comprising:

[0018] The sleeve body comprises a rod portion and a flange portion and a bell mouth portion respectively formed at two ends of the rod portion, and a through hole penetrating the flange portion and the bell mouth portion is provided in the rod portion;

[0019] The minimum inner diameter of the bell-mouth portion is consistent with the outer diameter of the rod portion, and the maximum inner diameter of the bell-mouth portion is greater than the outer diameter of the rod portion.

[0020] Furthermore, the outer diameter of the flange portion is greater than the outer diameter of the rod portion.

[0021] Furthermore, the end surface of the flange portion is flush with the end surface of the rod portion.

[0022] Furthermore, an end surface of the bell-mouth portion is flush with the other end surface of the rod portion.

[0023] The present application also discloses a device for forming a special-shaped riveted sleeve, the riveted sleeve comprising a sleeve body, the sleeve body comprising a rod and a flange and a bell mouth respectively formed at both ends of the rod, the rod is provided with a through hole penetrating the flange and the bell mouth, comprising:

[0024] A cold heading machine and a die assembly mounted on the cold heading machine;

[0025] The mold assembly includes: a main mold sleeved on the outside of the rod part, and a punch die abutting against the end face of the flange part. The main mold can abut against the bottom of the flange part, and the main mold can punch out a through hole penetrating the rod part from bottom to top, and the punch die can punch out a bell-mouth part at the bottom of the through hole from top to bottom.

[0026] Furthermore, the mold assembly includes six molds, and each of the six molds includes a main mold and a punching die arranged corresponding to the main mold.

[0027] The beneficial effects of the present invention are as follows:

[0028] 1. The one-time cold heading forming process is adopted to overcome the traditional cold heading and machining forming process. For the problem that products with small middle diameter and large end diameter cannot be demoulded, the inherent idea is abandoned and the structure of the front station rod forming into a chamfered part is adopted, so that the metal strength of the chamfered part becomes lower, which is convenient for stamping and forming. Then, through the action of the back station die, the chamfered part flows radially and gradually deforms to form a bell-mouth part at the bottom of the rod. This process greatly improves production efficiency, reduces production costs, shortens production cycles, and improves quality stability.

[0029] 2. Pre-form a chamfered portion at the bottom of the through hole to reduce the edge strength of the chamfered portion, making it easier to deform under stamping, and facilitating the subsequent forming of the bell mouth portion.

[0030] In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, preferred embodiments are specifically cited below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0032] Figure 1 is a cross-sectional view of a pressure riveted sleeve in an embodiment of the present invention;

[0033] Figure 2 is a bottom view of a pressure-riveted sleeve in an embodiment of the present invention;

[0034] Figure 3 Embodiment of the present invention Figure 1 A magnified view of the bell mouth at center A;

[0035] Figure 4 It is a cross-sectional view of a riveted sleeve formed in a fifth die in an embodiment of the present invention.

[0036] The figure numbers of the above drawings are: 10, sleeve body; 11, rod portion; 12, flange portion; 13, bell mouth portion; 14, through hole; 15, chamfered portion. DETAILED DESCRIPTION

[0037] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] It should be noted that the terms "first", "second", "third", etc. are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the features.

[0039] The forming method, the forming sleeve and the device for forming the special-shaped self-riveting sleeve described in the present application adopt a one-time cold heading forming process to overcome the traditional forming process combining cold heading and machining. For the problem that the product with a small middle diameter and a large end diameter cannot be demolded, the inherent idea is abandoned and the structure of the front station rod portion being formed into a chamfered portion is adopted, so that the metal strength of the chamfered portion is reduced, which is convenient for stamping and forming. Then, through the action of the back station die, the chamfered portion flows radially and gradually deforms so that the bottom of the rod portion is formed into a bell-mouth portion. The use of this process greatly improves production efficiency, reduces production costs, shortens production cycles, and improves quality stability.

[0040] The following is combined with Figures 1 to 4 The present invention is described in detail with reference to the accompanying drawings and embodiments.

[0041] The forming method of the special-shaped riveted sleeve described in this embodiment comprises the following steps:

[0042] First, the wire is placed in the main die cavity, and the punch moves from top to bottom until it abuts against the end face of the wire and cold-forges it, thereby forming a flange 12 at one end of the wire and a rod 11 connected to the bottom of the flange 12. The outer diameter of the flange 12 is greater than the outer diameter of the rod 11.

[0043] Secondly, the main mold punches a through hole 14 from bottom to top from one end of the rod 11 away from the flange 12. The through hole 14 passes through the rod 11 and the flange 12. A chamfered portion 15 is provided at the bottom of the through hole 14. The inner diameter of the chamfered portion 15 gradually increases toward the bottom end of the rod 11. The maximum inner diameter of the chamfered portion 15 is consistent with the outer diameter of the rod 11.

[0044] Then, the punching die performs punching from the end face of the flange portion 12 from top to bottom. The ejector pin of the punching die enters the through hole 14, so that the chamfered portion 15 flows radially under the action of the punching die. The inclined surface of the chamfered portion 15 gradually deforms to form a bell-mouth portion 13 at the bottom end of the rod portion 11. The diameter of the bell-mouth portion 13 gradually increases toward the side away from the flange portion 12. The maximum inner diameter of the bell-mouth portion 13 is greater than the outer diameter of the rod portion 11.

[0045] Finally, the wire material formed with the flange portion 12, the rod portion 11 and the bell mouth portion 13 is electroplated to form a riveted sleeve. The operator performs a final inspection on the formed riveted sleeve. After confirming that there are no quality problems in the final inspection, the riveted sleeve is packaged.

[0046] Specifically, in this embodiment, in the step of "the punching die is abutted against the end surface of the wire material, and the wire material is cold headed from top to bottom to form the flange portion 12 and the rod portion 11 connected to the bottom of the flange portion 12", the following steps are included:

[0047] First, an operator cuts the wire with scissors and clamps it into a first mold cavity with a clamp, and flattens two opposite end faces of the wire with a first punch.

[0048] Secondly, the flattened wire is clamped into the second main die cavity by a clamp, and the second punch ejector enters the second main die cavity from top to bottom to punch to increase the diameter of the rod 11.

[0049] Then, the wire is clamped into the third main die cavity by a clamp, and the third punching die ejector punches the preformed flange portion 12 from the end surface of the wire from top to bottom. The preformed flange portion 12 is formed to about 70% of the final flange portion 12.

[0050] Finally, the wire is clamped into the fourth main die cavity by a clamp, and the fourth punch ejector continues to punch from top to bottom to form the flange portion 12 .

[0051] Specifically, in this embodiment, the maximum diameter of the chamfered portion 15 is consistent with the diameter of the rod portion 11 .

[0052] Specifically, in this embodiment, the minimum inner diameter of the bell mouth 13 is consistent with the outer diameter of the rod 11. The maximum inner diameter of the bell mouth 13 is greater than the outer diameter of the rod 11, so that the bell mouth 13 is easy to be put on the car bumper, thereby realizing the connection between the bumper and the car body.

[0053] By using the above one-time cold heading forming method, the traditional cold heading and machining combined forming process is overcome. For the problem that the product with a small middle diameter and a large end diameter cannot be demoulded, the inherent idea is abandoned and the structure of the front station rod 11 forming the chamfered portion 15 is adopted, so that the metal strength of the chamfered portion 15 becomes low, which is convenient for stamping and forming. Then, through the action of the back station die, the chamfered portion 15 flows radially and gradually deforms so that the bottom of the rod 11 forms the bell mouth portion 13. The use of this process greatly improves production efficiency, reduces production costs, shortens production cycles, and improves quality stability.

[0054] Specific reference Figure 1 , Figure 2 and Figure 3 This embodiment also discloses a special-shaped riveted sleeve, including:

[0055] The sleeve body 10. The sleeve body 10 is roughly cylindrical. The sleeve body 10 includes a rod 11 and a flange 12 and a bell-mouth 13 respectively formed at both ends of the rod 11. The outer diameter of the flange 12 is greater than the maximum inner diameter of the bell-mouth 13. The portion where the flange 12 is connected to the rod 11 is an arc-shaped surface. A through hole 14 is provided in the rod 11, which passes through the flange 12 and the bell-mouth 13. Among them, the minimum inner diameter of the bell-mouth 13 is consistent with the outer diameter of the rod 11. The maximum inner diameter of the bell-mouth 13 is greater than the outer diameter of the rod 11.

[0056] Specifically, in this embodiment, the outer diameter of the flange portion 12 is greater than the outer diameter of the rod portion 11 , so that the flange portion 12 can be tightly connected to the vehicle body.

[0057] Specifically, in this embodiment, the end surface of the flange portion 12 is flush with the end surface of the rod portion 11, so that the flange portion 12 can abut against the vehicle body without wasting raw materials.

[0058] Specifically, in this embodiment, the end surface of the bell-mouth portion 13 is flush with the other end surface of the rod portion 11 to save raw materials and reduce production costs.

[0059] This embodiment also discloses a device for forming a special-shaped riveted sleeve, the riveted sleeve comprising a sleeve body 10. The sleeve body 10 comprises a rod 11 and a flange 12 and a bell-mouth 13 respectively formed at both ends of the rod 11. A through hole 14 penetrating the flange 12 and the bell-mouth 13 is provided in the rod 11. The device for forming a special-shaped riveted sleeve comprises: a cold heading machine and a die assembly mounted on the cold heading machine. The production speed of the cold heading machine is 60 pieces per minute. The die assembly comprises: a main die sleeved on the outside of the rod 11 and a punch die abutting against the end face of the flange 12. The main die can abut against the bottom of the flange 12. The main die can punch out a through hole 14 penetrating the rod 11 from bottom to top. The punch die can punch out the bell-mouth 13 from the bottom of the through hole 14.

[0060] Specifically, in this embodiment, the mold assembly includes six molds. The six molds each include a main mold and a punching die corresponding to the main mold. The main mold includes a main mold shell, a main mold core, a main mold cushion block, a main mold push sleeve, a main mold ejector pin and other components. The punching die includes a punching die shell, a punching die cushion block, a punching die ejector pin, a punching die sleeve and other components.

[0061] By means of the above structure, the shape feature of the bell mouth portion 13 of the rod portion 11 is formed in one step by cold heading forming process, thus avoiding the conventional machining method, greatly improving the production efficiency and reducing the production cost.

[0062] Specific embodiments are used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A method for forming a special-shaped riveted sleeve, characterized in that: The following steps are involved: The die is pressed against the end face of the wire and cold-forged from top to bottom to form a flange and a rod connected to the bottom of the flange; the wire is cut and clamped into the first die cavity, and the two opposite end faces of the wire are flattened by the first die; the flattened wire is clamped into the second main die cavity, and the second die ejector punches from top to bottom to increase the diameter of the rod; the wire is clamped into the third main die cavity, and the third die ejector punches from the end face of the wire from top to bottom to preform the flange; the wire is clamped into the fourth main die cavity, and the fourth die ejector continues to punch from top to bottom to form the flange; A through hole penetrating the rod and the flange is punched from bottom to top from one end of the rod away from the flange, wherein a chamfered portion is provided at the bottom of the through hole, and the inner diameter of the chamfered portion gradually increases toward the bottom end of the rod; Punching is performed from the end surface of the flange portion, and the chamfered portion flows radially under the action of the punching die, so that the diameter of the bottom end of the rod portion gradually increases toward the side away from the flange portion, forming a bell mouth portion; Electroplating the wire material with flange, stem and bell mouth to form a riveted sleeve; The maximum inner diameter of the chamfered portion is consistent with the outer diameter of the rod portion; The minimum outer diameter of the bell mouth portion is consistent with the outer diameter of the rod portion, and the maximum outer diameter of the bell mouth portion is greater than the outer diameter of the rod portion.

2. A special-shaped riveted sleeve, characterized in that: The special-shaped riveted sleeve is made by the molding method of claim 1, which includes: The sleeve body comprises a rod portion and a flange portion and a bell mouth portion respectively formed at two ends of the rod portion, and a through hole penetrating the flange portion and the bell mouth portion is provided in the rod portion; The minimum outer diameter of the bell-mouth portion is consistent with the outer diameter of the rod portion, and the maximum outer diameter of the bell-mouth portion is greater than the outer diameter of the rod portion.

3. The special-shaped self-riveting sleeve according to claim 2 is characterized in that: The outer diameter of the flange portion is greater than the outer diameter of the rod portion.

4. The special-shaped self-riveting sleeve according to claim 2, characterized in that: The end surface of the flange portion is flush with the end surface of the rod portion.

5. The special-shaped self-riveting sleeve according to claim 4 is characterized in that: The end surface of the bell mouth portion is flush with the other end surface of the rod portion.

6. A device for forming a special-shaped riveted sleeve, the riveted sleeve comprising a sleeve body, the sleeve body comprising a rod and a flange and a bell mouth formed at both ends of the rod, the rod is provided with a through hole penetrating the flange and the bell mouth, characterized in that: The forming method for the special-shaped riveted sleeve according to claim 1 comprises: A cold heading machine and a die assembly installed on the cold heading machine; the die assembly includes six dies, each of which includes a main die and a punch die corresponding to the main die, the main die includes a main die shell, a main die core, a main die pad, a main die push sleeve, and a main die ejector, and the punch die includes a punch die shell, a punch pad, a punch ejector, and a punch sleeve.

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