RU2393649C1 - Induction heater of bushing surface - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: induction heater of bushing surface consists of first inductor made in form of cylinder coil out of cooled current conducting tube connected to high frequency current source and inserted inside aperture of bushing with gap and of second inductor identical to first one. Also turns of coils of the first and the second inductors alternate forming periodic sequence. Ends of coils are joined with a jumper, while starts are connected to the source of high frequency current Distance between surfaces of neighbour turns of coils is not less, than one third of the gap between heated surface of the bushing and surface of a coil turn.

EFFECT: expanded efficiency of inductor for through heating for heating surface of small diametre apertures.

2 cl, 1 dwg.

Description

The invention relates to techniques for induction heating and can find application in devices for heat treatment of the inner and outer cylindrical surfaces of metal products, in particular, in devices for heating the inner surface of the bushings.

Known rod inductor for induction heating of the inner surface of the sleeve with a hole [1. Sukhotsky A.E. Inductors - L.: Mechanical Engineering, 1989, p.30]. The rod inductor is made in the form of a water-cooled copper tube connected via detachable clamps with tires with a step-down transformer and placed with a gap inside the hole of the heated sleeve. The disadvantage of the rod inductor [1] is the uneven heating of the inner surface of the sleeve, due to the fact that due to the ring effect, the greatest heating occurs from the side of the sleeve facing the transformer. The consequences of uneven heating can occur in the form of uneven wear on the inner surface of the sleeve with the subsequent loss of its performance.

Known inductors for through heating, providing uniform heating of cylindrical surfaces, such as an inductor [2. A.S. No. 875650, MKI Н05В 6/38] for heating the inner surface of the holes, made in the form of a cylindrical coil from a water-cooled current lead, on the axis of which one of the conductors connecting the coil to a high-frequency current source is placed.

The inductor [2] for through heating the surface of the holes is taken as a prototype of the claimed device.

The disadvantage of the inductor [2] is the limited ability to heat the surface of the holes of small diameter, due to the fact that on the axis of the cylindrical coil there is one of the conductors connecting the coil with a high-frequency current source and preventing the diameter of the cylindrical coil from decreasing.

The aim of the invention is to expand the possibility of heating the surface of the holes of small diameter with an inductor for through heating.

This goal is achieved by the fact that the proposed induction heater of the surface of the bushings, containing the first inductor, made in the form of a cylindrical spiral from a cooled conductive tube connected to a high-frequency current source and placed with a gap inside the hole of the heated sleeve, is equipped with a second, identical to the first, inductor, and the turns the spirals of the first and second inductors alternate, forming a periodic sequence, the ends of the spirals are connected by a short, and the beginning of the spirals are connected to high frequency current source. In addition, in order to increase the heating efficiency in the proposed induction heater, the distance between the surfaces of the adjacent turns of the spirals is at least three clearance values between the heated surface of the sleeve and the surface of the spiral coil.

The drawing shows in a simplified form the proposed induction heater of the surface of the bushings.

The numbers in the drawing indicate: 1 - the spiral of the first inductor, 2 - the spiral of the second inductor, 3 - short, 4 - heated sleeve.

The work of the proposed induction heater is as follows.

In an induction heater, alternating turns of spirals 1 and 2 from a cooled conductive tube form a bifilar winding closed at the end by short-circuit 3 and connected to a high-frequency current source (not shown). When a high-frequency current passes, the winding in the working volume excites a magnetic field perpendicular to the axis of the sleeve, inducing eddy currents on the surface of the sleeve to heat the surface of the sleeve. For predominant heating of the surface of the sleeve, and not the surface of adjacent turns of spirals, the distance between the surfaces of adjacent turns of spirals is at least three values of the gap between the heated surface of the sleeve and the surface of the spiral coil.

Introduction to the composition of the induction heater of the second spiral inductor, which simultaneously implements induction heating of the surface of the sleeve and the connection of the first spiral inductor with the current source, allows to exclude from the design of the induction heater the conductor located on the axis of the spiral inductor. In turn, the absence of a current lead arranged on the axis of the spiral inductor expands the possibilities of heating the surface of small diameter holes with the proposed induction heater.

Claims (2)

1. An induction heater of the surface of the bushings containing the first inductor, made in the form of a cylindrical spiral from a cooled conductive tube connected to a high-frequency current source and placed with a gap inside the hole of the heated sleeve, characterized in that it is equipped with a second, identical to the first, inductor, and the coils are spiral the first and second inductors alternate, forming a periodic sequence, the ends of the spirals are shorted, and the beginning of the spirals are connected to a high-frequency current source. 2. The induction heater of the surface of the bushings according to claim 1, characterized in that the distance between the surfaces of adjacent turns of the spirals is at least three values of the gap between the heated surface of the sleeve and the surface of the coil of the spiral.