Ultra-short rod type fastener cold heading die

Abstract

The utility model discloses an ultra-short rod type fastener cold heading die which comprises an upper die block and a lower die block, a blank head positioning groove hole is formed in the parting surface of the upper die block, a blank rod forming cavity is formed in the parting surface of the lower die block, and an ejector is arranged in the lower die block. A boss forming cavity is formed in the cavity wall of the blank rod part forming cavity and is used for forming a limiting boss on the blank rod part; through the ingenious mold structure design, continuous automatic production is achieved, procedures are reduced, and efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the field of fastener cold heading dies, in particular to an extremely short rod type fastener cold heading die. Background Art

[0002] like Figure 1 As shown, the ultra-short rod fastener is mainly composed of a head 1 and a rod 2. It has always been difficult to use ordinary cold heading machines to continuously mass-produce ultra-short rod fasteners. The main reason is that the rod of the blank is too short and the friction with the lower die cavity is too small, resulting in the upper die being pulled out of the lower die cavity due to the large friction, so that the clamp cannot clamp the blank and continuous production cannot be achieved.

[0003] The existing production method is to use the heading and then trim the edges in sequence or use special equipment to make the rod, which has the problems of low efficiency and high scrap rate; or to add a set of ejection mechanism in the cold heading upper die, which has a complex structure and is easy to cause the blank to fall, resulting in a high scrap rate. Summary of the invention

[0004] The utility model provides a cold heading die for an extremely short rod type fastener, aiming to solve the technical problem that the extremely short rod type fastener cannot be continuously produced on a cold heading machine.

[0005] In order to solve the above technical problems, the technical solution of the utility model is: a cold heading die for an extremely short rod type fastener, comprising an upper module and a lower module, a blank head positioning slot is provided on the parting surface of the upper module, a blank rod forming cavity is provided on the parting surface of the lower module, and a ejector is provided in the lower module, characterized in that a boss forming cavity is provided on the cavity wall of the blank rod forming cavity, and the boss forming cavity is used to form a limiting boss on the blank rod.

[0006] The above technical solution is further limited in that the boss forming cavity is an annular groove.

[0007] The above technical solution is further limited in that the depth H of the annular groove is greater than the width B.

[0008] The above technical solution is further limited in that the ejector is an ejector pin, and an ejector pin cavity communicating with the forming cavity of the blank rod portion is provided in the lower module.

[0009] Beneficial effects: 1) The utility model realizes continuous automatic production through ingenious mold structure design, reduces working procedures and improves efficiency; 2) The structure is simple, no additional installation and adjustment is required, and the cost is low; 3) The depth and width of the boss forming cavity are calculated and selected according to the material and size of the produced parts and the friction force of the upper mold, forming a series with strong promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural diagram of an extremely short rod type fastener in the background technology.

[0011] Figure 2 It is a structural diagram of the utility model.

[0012] Figure 3 It is a structural diagram of the middle and lower modules of the utility model.

[0013] Figure 4 This is the extrusion state diagram of the blank in the lower module.

[0014] Figure 5 This is the ejection state diagram of the blank. DETAILED DESCRIPTION

[0015] like Figure 2 and Figure 3 As shown, a cold heading die for an extremely short rod type fastener comprises an upper module 3 and a lower module 4, a blank head positioning slot 301 is provided on the parting surface of the upper module, a blank rod forming cavity 401 is provided on the parting surface of the lower module, a ejector 5 is provided in the lower module, a boss forming cavity 402 is provided on the cavity wall of the blank rod forming cavity, and the boss forming cavity is used to form a limiting boss on the blank rod;

[0016] like Figure 2 and Figure 3 As shown, the boss forming cavity is an annular groove, and this structure is easy to process and use, and does not require additional installation or adjustment;

[0017] like Figure 3 As shown, the depth H and width B of the annular groove are calculated and selected according to the material and size of the produced parts, as well as the friction force, wherein H must be greater than 2 times of B to avoid defects such as folding and pulling marks on the rod of the part;

[0018] like Figure 3 As shown, the boss forming cavity is provided with a draft angle and a smooth transition at the common edge, so that the blank can be ejected smoothly, while avoiding the expansion of the blank in the annular groove, which may cause defects such as folding and pulling marks on the rod of the part after ejection.

[0019] like Figure 2 As shown, the ejector is an ejector pin, and an ejector pin cavity communicating with the forming cavity of the blank rod portion is provided in the lower module.

[0020] The utility model utilizes the characteristic that cold-formed materials are easy to deform, and processes an annular groove at an appropriate position in the inner cavity of the lower die. The annular groove structure can hold the blank and keep it in the lower die. When the head is upsetting, the deformation force makes the rod fill the lower die. At this time, the blank material also fills the annular groove, that is, an annular limiting boss 201 (such as Figure 4As shown in the figure). When the upper punch returns, although there is friction between the blank and the upper die, the mechanical resistance of the lower die annular groove is greater than the friction of the upper die. Therefore, the blank naturally separates from the upper die and remains in the lower die. Figure 5 As shown, the strong ejection force of the lower ejector pin overcomes the mechanical resistance of the annular groove, ejects the blank out of the lower die, is smoothly clamped by the clamp 6, and sent to the next station, thereby realizing continuous automatic production. During the ejection process, because the blank rod is ejected from the mold forming cavity, the limiting boss on the blank is forced to squeeze back into a part of the blank rod. The size of the blank rod after ejection meets the design requirements and there is no limiting boss.

Claims

1. A cold heading die for an extremely short rod fastener, comprising an upper die block and a lower die block, wherein a blank head positioning slot is provided on the parting surface of the upper die block, a blank rod forming cavity is provided on the parting surface of the lower die block, and a material ejector is provided in the lower die block, characterized in that: A boss forming cavity is provided on the cavity wall of the blank rod forming cavity, and the boss forming cavity is used to form a limiting boss on the blank rod.

2. According to claim 1, a cold heading die for an extremely short rod type fastener, characterized in that: The boss forming cavity is an annular groove.

3. According to claim 2, a cold heading die for an extremely short rod type fastener, characterized in that :The depth H of the annular groove is greater than the width B.

4. A cold heading die for an extremely short rod type fastener according to claim 3, characterized in that: The ejector is an ejector pin, and an ejector pin cavity communicating with the forming cavity of the blank rod portion is arranged in the lower module.

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