Fastener head arc turning hob

Abstract

The utility model relates to the field of fastener machining, and discloses a fastener head arc turning hob which comprises a hob handle, a U-shaped opening is formed in the middle of the front end of the hob handle, a mounting hole transversely penetrating through the two side walls of the U-shaped opening is formed in the front end of the hob handle, a supporting bolt is arranged in the mounting hole in a penetrating mode, and an extrusion wheel is rotationally connected to the supporting bolt in the U-shaped opening. Plane thrust bearings are arranged between the two sides of the extrusion wheel and the side wall of the U-shaped opening, and the two plane thrust bearings extrude and limit the extrusion wheel to be located in the middle of the U-shaped opening from the two sides. The utility model can solve the problem that the arc chamfer between the head part and the rod part of the bolt is not smooth in the cold heading extrusion forming process of the bolt in the prior art.

Description

Technical Field

[0001] The utility model relates to the field of fastener processing, in particular to a hob for circular arc turning of a fastener head. Background Art

[0002] The production of fasteners such as bolts and screws usually involves annealing, drawing, cutting, cold heading, and then thread rolling or thread rolling. The head of the bolt is formed during the cold heading process, and the transition between the head and the rod is designed as a circular chamfer transition. The circular chamfer is usually extruded by a cold heading die. However, in the actual production process, it is found that the arc chamfer formed by cold heading extrusion does not meet the requirements, and the circular chamfer is not smooth, which affects the quality of the bolt products. When the bolt products are used, there is a gap between the head and the assembly parts, and they cannot be assembled stably and reliably. In addition, the chamfer is not smooth and there is a problem of insufficient structural strength, which is easy to cause damage at the chamfered part, resulting in failure of the bolt connection. Utility Model Content

[0003] The utility model aims to provide a hob for arc turning of a fastener head, so as to solve the problem that the arc chamfer between the bolt head and the rod is not smooth in the cold heading extrusion forming in the bolt production process in the prior art.

[0004] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a fastener head arc turning hob, including a handle, a U-shaped opening is provided in the middle of the front end of the handle, a mounting hole is provided at the front end of the handle and transversely penetrates the two side walls of the U-shaped opening, a supporting bolt is passed through the mounting hole, an extrusion wheel is rotatably connected to the supporting bolt in the U-shaped opening, and planar thrust bearings are provided between the two sides of the extrusion wheel and the side walls of the U-shaped opening, and the two planar thrust bearings squeeze and limit the extrusion wheel located in the middle of the U-shaped opening from both sides.

[0005] Preferably, as an improvement, the rod portion of the support bolt includes a threaded section and a smooth rod section, the outer diameter of the threaded section is smaller than the smooth rod section, and the length of the smooth rod section is greater than three quarters of the width of the handle.

[0006] Preferably, as an improvement, the threaded section of the support bolt is connected to a nut after passing through the handle, and elastic washers are provided between the head of the support bolt, the nut and the outer wall of the handle.

[0007] Preferably, as an improvement, a wear-resistant copper sleeve is provided between the inner hole of the extrusion wheel and the bare rod section of the support bolt.

[0008] Preferably, as an improvement, the extrusion wheel is a disc-shaped carbide wheel, and the edge of the extrusion wheel is an arc transition.

[0009] The principle and advantages of this scheme are: in actual application, the hob of this scheme is clamped on the lathe for use, and the bolt to be processed is also clamped on the lathe. The lathe drives the bolt to rotate, and the hob of this scheme is moved to squeeze and contact the transition part between the bolt head and the rod. The extrusion wheel rolls under the action of friction to cold-extrude the transition part between the bolt head and the rod, repairing the arc chamfer that has not been processed in place during the cold heading process of the bolt, making the arc chamfer smoother. The handle provides structural support, and the support bolt serves as the rotation support shaft of the extrusion wheel. The length of the support bolt rod section is designed so that it can be stably and reliably connected to the mounting holes on both sides of the U-shaped opening and provide stable and reliable support for the extrusion wheel. Elastic washers are set at the head and tail of the support bolt to ensure the stability of the support bolt connection. The plane thrust bearings on both sides of the extrusion wheel stabilize the extrusion wheel from both axial sides, ensuring the smooth rotation of the extrusion wheel while avoiding axial movement of the extrusion wheel, and ensuring the stable extrusion of the arc chamfer of the bolt by the extrusion wheel. The wear-resistant copper sleeve reduces the friction between the extrusion wheel and the bare rod section of the supporting bolt, further ensuring the smooth rotation of the extrusion wheel, which is beneficial to avoid wear of the inner hole of the extrusion wheel and increase the service life of the extrusion wheel. The extrusion wheel adopts a disc-shaped carbide wheel, which has high structural strength and better extrusion molding effect on the arc chamfer of the bolt. The use of this scheme to turn and roll the arc chamfer between the bolt head and the rod can effectively repair the arc chamfer and the arc degree, making the arc chamfer smoother. It can also cold-extrude and cold-work harden the arc chamfer part, which can improve the structural strength of the arc chamfer between the bolt head and the rod. In addition, the hidden defects in the arc chamfer part can be extruded and repaired to improve the quality of the bolt products. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a structural schematic diagram of an embodiment of the utility model. DETAILED DESCRIPTION

[0011] The following is further described in detail through specific implementation methods:

[0012] The reference numerals in the drawings of the specification include: a handle 1, a U-shaped opening 2, a support bolt 3, an extrusion wheel 4, an elastic washer 5, a wear-resistant copper sleeve 6, a plane thrust bearing 7, and a nut 8.

[0013] The embodiment is basically as shown in the attached Figure 1As shown: a circular arc turning hob for the head of a fastener, comprising a rectangular rod-shaped handle 1, a U-shaped opening 2 is provided in the middle of the front end of the handle 1, a mounting hole is provided at the front end of the handle 1 which passes through the two side walls of the U-shaped opening 2 in a transverse direction, a support bolt 3 is passed through the mounting hole, the rod portion of the support bolt 3 comprises a threaded section and a polished section, the outer diameter of the threaded section is smaller than the polished section, and the length of the polished section is greater than three quarters of the width of the handle 1, so that after the support bolt 3 is passed through, the polished section is inserted into the mounting holes on both sides of the U-shaped opening 2. After the threaded section of the support bolt 3 passes through the handle 1, a nut 8 is connected, and an elastic washer 5 is provided between the head of the support bolt 3, the nut 8 and the outer wall of the handle 1. An extrusion wheel 4 is sleeved on the support bolt 3 in the U-shaped opening 2, and a wear-resistant copper sleeve 6 is provided between the inner hole of the extrusion wheel 4 and the polished section of the support bolt 3. The extrusion wheel 4 is a disc-shaped carbide wheel, and the edge of the extrusion wheel 4 is an arc transition. Planar thrust bearings 7 are provided on the support bolts 3 between the two sides of the extrusion wheel 4 and the side walls of the U-shaped opening 2. The two planar thrust bearings 7 squeeze and limit the extrusion wheel 4 from both sides to be located in the middle of the U-shaped opening 2.

[0014] The specific implementation process is as follows: the hob of this scheme is clamped on the lathe for use, and the bolt to be processed is also clamped on the lathe. The lathe drives the bolt to rotate, and the hob of this scheme is moved to squeeze and contact the transition part between the bolt head and the rod. The extrusion wheel 4 rolls under the action of friction to cold-work and extrude the transition part between the bolt head and the rod, repairing the arc chamfer that was not processed in place during the cold heading process of the bolt, making the arc chamfer smoother. The handle 1 provides structural support, and the support bolt 3 serves as the rotation support shaft of the extrusion wheel 4. The length of the bare rod section of the support bolt 3 is designed so that it can be stably and reliably connected to the mounting holes on both sides of the U-shaped opening 2 and provide stable and reliable support for the extrusion wheel 4. The elastic washers 5 are set at the head and tail of the support bolt 3 to ensure the stability of the connection of the support bolt 3. The plane thrust bearings 7 on both sides of the extrusion wheel 4 stably limit the extrusion wheel 4 from both axial sides, ensuring that the extrusion wheel 4 rotates smoothly while avoiding axial movement of the extrusion wheel 4, and ensuring the stable extrusion of the arc chamfer of the bolt by the extrusion wheel 4. The wear-resistant copper sleeve 6 reduces the friction between the extrusion wheel 4 and the bare rod section of the support bolt 3, further ensuring the smooth rotation of the extrusion wheel 4, which is beneficial to avoid wear of the inner hole of the extrusion wheel 4 and increase the service life of the extrusion wheel 4. The extrusion wheel 4 adopts a disc-shaped carbide wheel, which has high structural strength and better extrusion molding effect on the arc chamfer of the bolt. The present scheme is used to perform lathe processing and rolling on the arc chamfer between the bolt head and the rod, which can effectively repair the arc chamfer and the arc degree, making the arc chamfer smoother, and can also perform cold extrusion and cold hardening on the arc chamfer part, which can improve the structural strength of the arc chamfer between the bolt head and the rod. In addition, the defects hidden in the arc chamfer part can be extruded and repaired to improve the quality of the bolt product.

[0015] The above is only an embodiment of the utility model, and the common knowledge such as the known specific technical solutions and / or characteristics in the solution is not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the utility model, several deformations and improvements can be made, which should also be regarded as the protection scope of the utility model, and these will not affect the effect of the implementation of the utility model and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.

Claims

1. The hob for arc turning of the fastener head is characterized by: It includes a knife handle, a U-shaped opening is provided in the middle of the front end of the knife handle, a mounting hole is provided at the front end of the knife handle which transversely penetrates the two side walls of the U-shaped opening, a supporting bolt is passed through the mounting hole, an extrusion wheel is rotatably connected to the supporting bolt in the U-shaped opening, planar thrust bearings are provided between the two sides of the extrusion wheel and the side walls of the U-shaped opening, and the two planar thrust bearings squeeze and limit the extrusion wheel located in the middle of the U-shaped opening from both sides.

2. The fastener head circular arc turning hob according to claim 1, characterized in that: The rod portion of the support bolt comprises a threaded section and a polished section, the outer diameter of the threaded section is smaller than that of the polished section, and the length of the polished section is greater than three quarters of the width of the handle.

3. The fastener head circular arc turning hob according to claim 2, characterized in that: The threaded section of the support bolt passes through the knife handle and is connected with a nut. Elastic washers are arranged between the head of the support bolt, the nut and the outer wall of the knife handle.

4. The fastener head circular arc turning hob according to claim 3, characterized in that: A wear-resistant copper sleeve is arranged between the inner hole of the extrusion wheel and the polished rod section of the supporting bolt.

5. The hob for circular arc turning of the fastener head according to claim 4, characterized in that: The extrusion wheel is a disc-shaped hard alloy wheel, and the edge of the extrusion wheel is an arc transition.

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