RO138389A2 - Technology for manufacturing a drive-chain bolt - Google Patents

Abstract

The invention relates to a technology for manufacturing a drive-chain bolt which is used in chains where the bolts are riveted, upon the chain mounting process (bicycle chain, agricultural chain, motorcycle chain). According to the invention, the bolt has a cylindrical shape where a part (T) thermally treated by diffusion is placed in the middle and, at the ends, it has a non-thermally treated part (N), in order for it to be riveted, and the bolt making process comprises several performing stages, in a first embodiment, cutting-rolling-diffusion thermal treatment-grinding-length cutting-end machining, the cutting being performed at a length that is a multiple of the final length of the bolts, n*1, plus an end cutting addition, the rolling is performed with a diameter difference D1-D2 depending on the final thickness of the bolt diffusion treatment plus a safety value, the thermal treatment is a diffusion one, with various substances, depending on the hardness desired to be obtained, the grinding is performed with a centerless grinder at such a depth that, the part with the bigger bolt diameter before the thermal treatment has, after grinding, the part with thermal treatment eliminated, the final length cutting is carried out at the bolt final length and, in this stage, the C value ends are also eliminated, in order to eliminate the treated part of the bolt ends, and the final machining of the ends is carried out to remove cutting deformations or various machining operations needed for the bolt ends.

Description

TRANSMISSION CHAIN BOLT MANUFACTURING TECHNOLOGY

The invention refers to the manufacturing technology of transmission chain lugs that are used for chains to which the lugs are riveted during the chain assembly process. (bicycle chain, agricultural chain, motorcycle chain, etc.).

Different technologies for the manufacture of the casing are known, but all of them have to respect the problem of limiting the thickness of the heat-treated layer due to the riveting of the casing during assembly. Different inventions have proposed increasing the hardness resulting from the boit diffusion treatment. Example EP-1219861 A, JP3656844B2 or others US10837519B2 to apply a treatment that results in a higher hardness for the barrel and a lower hardness for the bushing.

The problem that the invention solves is the realization of a manufacturing process of the boot in which the fat of the thermally treated layer is greater, and the hardness in the rivet area is lower.

The method of making the invention according to the drawings fig. 1-3:

Fig. 1- chain boit drawing;

Fig. 2. - drawings with the manufacturing cycle variant I;

Fig 3. - drawings with the manufacturing cycle variant Π;

The barrel according to the invention has a cylindrical shape in which the part thermally treated by diffusion is in the middle T, and at the ends it has a non-thermally treated portion N, so that it can be riveted.

The manufacturing process of the barrel: Variant I (fig. 2) includes several phases of execution: cutting-rolling-diffusion heat treatment-rectification-cutting to length-processing of the ends of the barrels.

The cutting is done at a length multiple of the final length of the pipes, n*l (+plus an allowance for cutting the ends).

Rolling is done with a difference in diameters D1-D2 depending on the final thickness of the boit diffusion treatment plus a safety value

The heat treatment is diffusion, with different substances, depending on the hardness we want to achieve.

Grinding is done with the grinding machine without centers at a depth so that, the part with the diameter of the boit before the heat treatment is larger, after the rectification, the part with the heat treatment is removed.

The final cutting to length is done at the final length of the boit and in this phase the ends of value C are also removed (to eliminate the treated part of the boit ends).

The final processing of the ends will be done to remove the deformations during cutting or different processing required for the bolt ends.

Processing variant Π (fig. 3) has the following stages:

- cutting-deposition of ceramic paint-diffusion heat treatment-cleaning ceramic paintrectification-cutting to length-processing of bolt ends.

The technological phases: cutting, rectification, cutting to length and processing the ends of the bolts is identical to version I.

Ceramic paint will be deposited on the portion that we do not want to be thermally treated by diffusion.

The cleaning of ceramic paint will be done by vibration in a mixture of bolts with abrasive elements.

The advantage of using the technology according to the invention:

By making the boit according to the invention it will have a thickness of the thermally treated layer by diffusion much greater than in the existing inventions (which leads to a longer life). By raising the heat-treated layer from the ends, the possibility of creating cracks during riveting as well as its wear will be reduced.

Claims (3)

1) The chain block according to (fig. 1) is made of a material suitable for heat treatment by diffusion, characterized by the fact that the technological manufacturing process has the following stages (fig. 2) Initial cutting-rolling-heat treatment by diffusion- rectification-final cutting-final processing of the ends of the shafts. 2) The chain block according to claim 1, characterized in that the technological manufacturing process has the following stages (fig. 3). Initial cutting - painting with ceramic paint, diffusion heat treatment - cleaning - rectification - final cutting - machining of the ends.