RU2608860C2 - Method of splined bushing recovery - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: invention relates to worn-out parts repair, in particular, to cardan shafts splined bushings recovery methods, and can be used in machine building. Method involves bushing splined surface damaged layer removal by means of drawing, application of composite material recovering layer with thickness in 1.1–2.5 times exceeding thickness of removed damaged layer, and formation of splines initial profile by drawing until production of splines nominal size. Used composite material is polyamide-11.

EFFECT: invention is aimed at increasing of splined connections durability.

1 cl, 4 dwg

Description

The invention relates to the repair of worn parts, in particular to a method for restoring a splined sleeve of a driveshaft, and can be used in mechanical engineering.

A known method of restoring worn side surfaces of the slots, including heating them with two electrode tools and distributing with a deforming tool, heating the side surfaces of the slots with two electrode tools for electromechanical processing, and distributing it with a deforming tool supplied from above, with said electrode tools on the same line and pressed against the lateral surfaces of the splines with forces selected from the condition of their displacement in the opposite direction by the amount of wear during Moreover, the electrode-tools and the deforming tool are moved together at the same speed (RF patent No. RU 2530924, IPC ВРР 6/00, published: October 20, 2014).

A known method of restoring a splined shaft, including preliminary distribution of the protrusions by the rollers in a locally heated zone across the generatrix along a helix with a step equal to the width of the rollers, with the rollers displaced relative to each other along the shaft axis by one step and 180 ° along the shaft rotation angle, the shaft is rotated in the direction that the roller moves from the unworn part of the protrusion to the worn out, surfacing of the protrusions and machining (RF patent No. RU 1581550, IPC В23Р 6/00, published: 07/30/1990).

The closest set of essential features to the claimed technical solution is a method of restoring splined shafts, including surfacing metal on the outer cylindrical surface of the splines. The axis of symmetry of the deposited volume of the metal is shifted from the axis of symmetry of the slot towards the worn side surface, and the amount of displacement is determined by the calculated dependence. Then the spline shaft is pulled through a deforming tool with the distribution of the deposited volume of metal over the entire surface of the slot. The tool comprises a housing with a central cylindrical hole and with grooves in which deforming inserts are installed. In this case, the deforming inserts are fixed around the circumference of the housing opening. The axis of symmetry of the deforming insert coincides with the axis of symmetry of the splines. The deforming inserts are mounted in the grooves of the housing with an interference fit (RF patent No. RU 1590307, IPC В23Р 6/00, published: September 7, 1990).

The disadvantages of the known technical solutions are the high energy intensity and the complexity of the recovery methods.

The task was to develop a method for restoring worn splines of the sleeve, which allows to increase the durability of the spline connection.

The problem is solved in that in the method for the restoration of splined bushings, including applying a recovery layer to the splined surface of the sleeve and subsequent formation of the initial profile of the splines by pulling, before applying the recovery layer using a specially designed broach, the damaged layer of the splined surface is removed, after which the layer is applied by any known method from a composite material, for example polyamide-11, with a thickness exceeding from 1.1 to 2.5 times the removed damaged layer, then ny initial profile forming broaching splines pulling until the nominal size of the slots.

Removing the damaged layer of the splined surface before applying the recovery layer made it possible to qualitatively prepare the surface for applying a uniform recovery layer from a composite material, for example polyamide-11, and forming the initial profile of the splines by pulling it with a broach to obtain a nominal size. This allows you to get a restored splined surface with high wear resistance (primarily due to the high wear resistance of the coating).

Using all of the above features can increase the durability of the spline connection.

An analysis of the known technical solutions carried out according to scientific, technical and patent documentation showed that the set of essential features of the claimed technical solution is not known from the prior art, therefore, it meets the conditions of patentability of the invention - “novelty” and “inventive step”.

The invention is illustrated by drawings:

FIG. 1 - profile of the slot before recovery;

FIG. 2 - slot profile after preliminary pulling;

FIG. 3 - profile of the slot with a applied recovery layer;

FIG. 4 - profile of the slot after finishing.

The method of restoring splined bushings consists in applying a reduction layer and subsequent machining.

The worn-out splined profile of the drive shaft sleeve is pulled with a specially designed broach to the thickness of the damaged layer, about 0.3 mm, then the surface of the splined profile is prepared for applying the recovery layer, i.e. they clean the surface, apply dry phosphate, a special primer (for adhesion) to the surface. A layer of composite material is applied to the prepared surface, for example, polyamide-11 "Rilsan" with a thickness of about 0.55-0.6 mm. Polyamide is applied to a surface preheated to a temperature of 300 ° C in a pseudo-boiling layer of a powder of a composite material, for example polyamide-11. After cooling the part to the workshop temperature and holding for about 24 hours, the initial profile of the splines is formed by pulling the broach to obtain the nominal size of the splines of the sleeve.

The restored prototypes of cardan shafts passed bench tests for durability. An analysis of the obtained results of durability tests showed that cardan shafts have the required durability, as they withstood the full scope of the tests, while maintaining operability.

All of these signs can reduce the coefficient of friction of the working surfaces, contribute to transmit increased torque up to 60% without permanent deformation for the driveshaft. And, as a result, they can increase the durability of the spline connection. Thus, the technical result is achieved.

The inventive method can be performed on standard equipment using well-known materials and technologies.

Claims (2)

1. The method of restoring the spline surface of the bushings, characterized in that they remove the damaged layer of the spline surface of the sleeve by pulling, after which a restoration layer of composite material is applied, the thickness of which is from 1.1 to 2.5, the thickness of the removed damaged layer, then the initial the profile of the splined surface of the sleeve by pulling until the nominal size of said splined surface is obtained. 2. The method according to p. 1, characterized in that polyamide-11 is used as a composite material.

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