RU153632U1 - DORN FOR SELECTIVE ELECTROMECHANICAL STRENGTHENING OF SURFACE HOLES OF PARTS - Google Patents

Abstract

Dorn for selective electromechanical hardening of the surfaces of the openings of the parts, comprising a current-insulating sleeve, a mandrel, coupling nuts and a reinforcing element configured to pass current at the contact point of the reinforcing element with the machining surface, characterized in that the mandrel is made with a thread by means of which a reinforcing is fixed on the mandrel an element that is made with a rectangular cut-out with the formation of two elastic segments with working surfaces, between which with a screw, a gate wedged into the hole in the end face of the mandrel, a wedge is fixed, with fillets made on the inside of the elastic segments and cylindrical cutouts made on the outside to reduce stress concentrations.

Description

Dorn for selective electromechanical hardening of hole surfaces of parts

The utility model relates to mechanical engineering, in particular, to tooling for surface hardening and can be used for hardening the internal surfaces of parts.

Known mandrel for selective electromechanical hardening of the inner surfaces of the parts [RU113198 B29D 30/12], containing a current-insulating sleeve, nut, mandrel, coupling nuts, characterized in that a reinforcing tooth is installed in the front of the mandrel, the reinforcing tooth is shaped and contains two working surfaces, located symmetrically relative to each other on the outer surface of the reinforcing tooth

Known mandrel for selective electromechanical hardening of the inner surfaces of the parts has the following disadvantages:

- quick uncompensated tool wear;

- crippling during processing due to poor contact of the tool with the work surface, accompanied by electrical erosion of the tool and part;

- the inability to adjust the amount of interference.

The technical result is an increase in the life of the mandrel for selective electromechanical hardening of the surfaces of the holes of the parts, ensuring reliable contact with the surface of the workpiece, the ability to adjust the amount of interference.

This goal is achieved by the fact that the mandrel is made with a thread, by means of which a reinforcing element is fixed on the mandrel, which is made with a rectangular cutout with the formation of two elastic segments with working surfaces, between which a wedge is fixed with a screw screwed into the hole in the end of the mandrel, moreover fillets are made on the inside of the elastic segments on the inside, and cylindrical cutouts are made on the outside to reduce stress concentrations.

In FIG. 1 shows a general view of the mandrel for selective electromechanical hardening of the surfaces of the holes of the parts, FIG. 2 - view A.

When the majority of the mating surfaces of the parts of the Shaft-Hole machines that accept an alternating radial cyclic load (for example, the bracket of the traction bar of the KS-F-2.1 B mower) are used, the main wear of the hole occurs on both sides along the load line. As a result, there is no need to harden the entire surface of the hole and it is advisable to use selective hardening.

The mandrel for selective electromechanical hardening of the surfaces of the openings of the parts includes a current-insulating sleeve 1, a mandrel 2, coupling nuts 3, a reinforcing element 4 made with the possibility of passing current at the point of contact of the reinforcing element with the processing surface. The mandrel 2 is made with a thread, by means of which a reinforcing element 4 is fixed to the mandrel, which is made with a rectangular cutout with the formation of two elastic segments 5 with working surfaces. A wedge 6 is fixed between the elastic segments 5 using a screw 7, which is screwed into the hole in the end of the mandrel, with fillets made on the inside of the elastic segments 5 and cylindrical cutouts on the outside to reduce stress concentrations.

They work with a mandrel for selective electromechanical hardening of the surfaces of the holes of the parts as follows. The tool is introduced into the hole to be machined, and with the help of a wedge, turning the screw creates the necessary interference. A current of density j = 250 ... 300 A / mm ^{2 is} passed through the contact point of the reinforcing element with the surface to be treated. As a result, the contacting surfaces of the reinforcing tooth with the inner surface of the hole are heated to a temperature of 900 ... 1000 ° C, and with subsequent axial movement of the mandrel relative to the axis of the hole, heat is instantly removed.

The use of a shaped reinforcing element with two elastic segments makes it possible to ensure reliable contact of the working surfaces with the work surface and to compensate for tool wear due to deformation of the elastic segments.

A wedge installed between the elastic segments, using a screw, allows you to adjust the interference fit.

Claims (1)

Dorn for selective electromechanical hardening of the surfaces of the openings of the parts, comprising a current-insulating sleeve, a mandrel, coupling nuts and a reinforcing element configured to pass current at the contact point of the reinforcing element with the machining surface, characterized in that the mandrel is made with a thread by means of which a reinforcing is fixed on the mandrel an element that is made with a rectangular cut-out with the formation of two elastic segments with working surfaces, between which with a screw, a gate wedged into the hole in the end face of the mandrel, a wedge is fixed, with fillets made on the inside of the elastic segments and cylindrical cutouts made on the outside to reduce stress concentrations.

Images