RU2489224C1 - Method of making bolts with flange - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and maybe used for production of wheel fasteners. Billet is cut to pre-head cylindrical head in diameter equal to that of hexagon circumscribing circle at first step of forming. At second step, rod and hexagonal head with edging for flange are reduced. At third step, hexagonal head and flange are finally headed while rod is gaged for thread cutting and facet is formed at its end. All jobs including thread cutting are made at one multi-position cold heading machine.

EFFECT: higher quality of bolts and tool durability, decreased metal input.

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Description

The invention relates to the processing of metals by pressure and can be used in the manufacture of bolts for mounting wheels.

A known method of manufacturing a bolt with a hex head and a flat washer, comprising feeding and cutting a workpiece; first reduction of the shaft and preliminary heading; the landing of the cylindrical head to a diameter slightly larger than the diameter of the described circumference of the hexagon bolt; the second reduction of the rod for threading, disembarking the washer and trimming the hexagon, trimming the washer and flashing the hexagon; chamfering and knurling (RD 37.002.0465-85. Cold forging of special fasteners and fittings. Technological processes and tools. - Gorky, 1986, p. 18, fig. 15).

The known method has the following disadvantages:

- increased consumption of metal, which in the last position goes into the flake;

- metal grooves on the surface of the flange and the hex head on the fourth and fifth transitions;

- low tool life when trimming the hex head and flange at the fourth and fifth transitions.

The closest technical solution is a method of manufacturing bolts with a flange, including a segment of the workpiece; first rod reduction; preliminary landing of a cylindrical head; preliminary reduction of the hex head and flange upset; reduction of the rod under knurling, the formation of the hexagon and flange (RF patent No. 2222408, class B21K 1/46).

However, the known method has several disadvantages:

- stable product quality is not ensured due to incomplete filling of the faces of the bolt head during its final formation from S = 14 to S = 17 mm, while performing this operation, large specific loads on the punch arise, which reduce its resistance;

- low resistance of the cold heading tool is manifested, especially in the fourth position as a result of the second reduction of the bolt blank rod, because violations of the surface layer of the phosphating coating are possible;

- the problem of obtaining a chamfer at the end of the rod for rolling the thread has not been solved;

- use five cold heading operations, i.e. the 2nd additional rod reduction operation is added using an expensive tool.

The technical problem to which the claimed invention is directed is to improve the quality of the parts obtained, reduce the consumption of metal and increase the durability of the cold head tool.

The problem is solved in that in the method of manufacturing bolts with a flange, the deformation of the head is carried out in three transitions, while at the first transition, a cylindrical head with a diameter d equal to the diameter of the described hexagon circle is preliminarily planted, then the rod and the hex head with a set of metal for the flange are reduced, and at the third transition, the hexagonal head and flange are finally planted and at the same time the rod is calibrated under the knurling of the thread with the formation of a chamfer at its end.

The invention is illustrated in the drawing, which shows the technological process of manufacturing bolts with a flange,

where d _zag is the diameter of the source metal;

d is the reducible diameter of the bolt head;

D is the described diameter of the hex bolt head;

S - turnkey hexagon size;

S _{1 is the} size of the reduced hexagon.

A method of manufacturing a bolt with a flange is as follows. On cold heading equipment mod. M20-4DBM from steel grade 38HGNM cut the workpiece with a diameter (d _zag ) of 15.7 mm. The shaping of the bolt begins with a piece of measured blanks of circular cross section. In the first position, a preliminary landing of the bolt head with a diameter d equal to the described diameter of the hexagon is made. In the second position, the hexagonal head of the bolt S _{1 is} reduced to the size of a turnkey hexagon S and the smooth part of the rod of the bolt blank for rolling the thread. In the third position, the final landing of the hex head of the bolt with the flange and the calibration of the rod are carried out. At the same position, a chamfer is simultaneously formed at the end of the bolt blank rod. Next, at the last position, the thread rolling operation on the bolt rod takes place.

All operations for manufacturing a bolt with a flange, including thread rolling, were performed on one multi-position cold heading equipment. The technology is trouble-free when receiving a head of a bolt and waste-free when receiving a facet on the end of a core without use of a sharp device.

Claims (1)

A method of manufacturing bolts with a flange, including cutting a workpiece, reducing the rod, forming a hexagonal head and flange, rolling the thread, characterized in that the shaping of the hexagonal head and flange is carried out in three transitions, while at the first transition, a cylindrical head is pre-planted with a diameter equal to the diameter the circumference of the hexagon, then simultaneously reduce the rod and the hex head with a set of metal under the flange, and at the third transition finally plant the hexagonal head and flange and at the same time calibrate the rod under the knurling of the thread with the formation of a chamfer at its end.

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