JPH0124210B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to an induction hardening device for integral constant velocity joints used in automobiles and the like.

(b) Prior Art In recent years, integrated constant velocity joints (hereinafter simply referred to as joints) have been used as joints in automobiles in place of conventional branched constant velocity joints. Due to its functionality, such a joint requires hardening of the transfer surface.

Therefore, as an apparatus for carrying out the above-mentioned hardening by so-called one-shot hardening, the joint is first placed directly on a suitable pedestal, and a vertical high-frequency heating coil configured to correspond to the transfer surface of the joint is installed. The coil is placed in the cavity of the joint, and while heating the transfer surface of the joint with this coil, a cooling liquid is injected from the outside of the joint to prevent the end surface of the joint from overheating. The joint was configured to be hardened by spouting a cooling liquid from the upper end opening of a cooling cylinder installed upright at the shaft center.

However, with such a hardening device, although it is possible to harden the transfer surface, it induces an electrical shot between the pedestal and the end face of the joint, thereby causing unnecessary spark discharge, and as a result, the end face is damaged. A phenomenon occurs in which a portion of the material melts in spots.

In the present invention, as a measure to prevent such spot melting of the end face, in order to insulate between the end face and the pedestal, experiments were carried out by changing the pedestal to an insulating material.

By changing the material of the pedestal, the spot melting caused by electrical shorts between the previous pedestal and the joint end face can be prevented.

However, as a result of further various experiments,
If insulation is simply achieved between the pedestal and the end face of the joint, the end face will tend to be overheated due to the high frequency eddy current that circulates around the end face during heating, and even if cooling liquid is injected from the outside of the joint, the cooling will not be possible The liquid only cools the outside of the end face, and the inner corner portions of the end face are not sufficiently cooled, so there is a drawback that the inner surface of the end face, especially the thick corner portions and thin corner portions, are partially overheated or melted. On the other hand, if high-frequency heating were to be saved in order to eliminate such drawbacks, vigorous hardening would be insufficient, making it impossible to reliably harden the transfer surface.

(c) Purpose This invention provides an induction hardening device that can perform sufficient induction hardening and prevents the inner surfaces of end faces, especially thick corners and thin corners, from being partially overheated or melted. With the goal.

(D) Structure This invention includes a high-frequency heating coil placed in a cavity of a joint, a cooling liquid injection means for rapidly cooling the cavity, a pedestal on which the joint is placed, and a pedestal and the joint that are insulated and isolated at a predetermined interval. This is an induction hardening apparatus equipped with means for cooling the end face of the joint.

(E) Embodiment FIG. 1 is a perspective view of the main parts of a joint, which is an object to be heated, related to the present invention, and FIG. 2 is a high-frequency heating coil, which is a component of an induction hardening apparatus, which is an embodiment of the present invention. FIG. 3(a) is a longitudinal sectional view showing the main part when the joint is set in the induction hardening apparatus for operation, and FIG. 3(b) is a sectional view taken along the line AA in FIG. 3(a).

That is, the joint 10 is formed into a cylindrical shape with a plurality of stepped parts as shown in the figure, and its end face gently connects the thick part 11 and the thin part 12, and the thick part 11 and the thin part 12. A transfer surface 13 is formed. Reference numeral 111 indicates an inner corner of the thick wall portion 11, and reference numeral 121 indicates an inner corner of the thin wall portion 12. Further, as shown in the figure, the high-frequency heating coil 20 is made of, for example, a square pipe material for cooling liquid circulation, and has horizontal connecting parts 21 and 23 that connect the vertical parts 22 and the vertical parts 22, and the above-mentioned parts are connected in series. It is connected to the.

The main part of the induction hardening equipment is the pedestal 31.
and the jacket 3 fixed on the periphery of the pedestal 31.
2, a small rectangular insulating spacer 33 that isolates a predetermined distance between the end face of the joint 10 and the pedestal 31;
It includes the high-frequency heating coil 20 disposed to heat the joint 10, and a cooling cylinder 34 erected at the axis of the joint.

Therefore, small coolant injection holes 311 are provided at predetermined locations of the pedestal 31, that is, locations corresponding to the thick wall portion 11 of the joint and the inner corner of the end surface of the transfer surface 13, for ejecting the coolant upward. A predetermined number of the jackets 32 are provided approximately vertically as possible.
A plurality of small holes 321 for jetting coolant for cooling the outside of the joint 10 are provided on the inner surface of the joint 10 .

Now, one embodiment of the operation of the apparatus configured as described above will be described.

First, the joint 10 is placed on the insulating spacer 33 with its end face facing down. Next, a required amount of coolant is injected from the small holes 311 and 321 for coolant injection. Next, the joint 10 is heated using a high frequency heating coil 20 according to a predetermined heating schedule. In this case, the current value, frequency, time, etc. are determined by the joint that is the object to be heated.

After heating for a predetermined period of time, a cooling liquid is jetted out from the upper end opening of the cooling tube 34 to rapidly cool and harden the joint.

Note that even after quenching, the injection of the cooling liquid from the small holes 311 and 321 for injection of the cooling liquid is continued if necessary.

(f) Effects Since the induction hardening apparatus according to the present invention has an insulating spacer between the joint and the pedestal, spark discharge as seen in the prior art does not occur.

Further, during heating of the joint, the coolant jetted out from the small coolant jetting hole 311 sufficiently cools the end face of the joint. Furthermore, the cooling liquid from the cooling liquid injection small hole 321 flows in the axial direction of the joint through the gap between the joint and the pedestal, and as a result, it sufficiently cools not only the outside of the joint but also its end face, as described above. The transfer surface can be reliably hardened without overheating or melting the specific end surface.

[Brief explanation of drawings]

Fig. 1 is a perspective view of the main part of a joint which is an object to be heated related to the present invention, Fig. 2 is a high frequency heating coil which is a component of an induction hardening apparatus which is an embodiment of the present invention, and Fig. 3 is a Fig. 3 is a vertical sectional view showing the main parts when the joint is set in the induction hardening apparatus and is operated; 10... joint, 20... high frequency heating coil, 31... cradle, 311, 321... small hole for cooling liquid injection, 33... insulating spacer, 34... cooling tube.

Claims (1)

[Claims] 1. An induction hardening device for an integral constant velocity joint, which includes: a high frequency heating coil placed in a cavity of the integral constant velocity joint; a cooling liquid injection means for rapidly cooling the cavity for hardening; and an integral constant velocity joint. A pedestal on which the pedestal is placed, a means for insulating and isolating the pedestal and the integrated constant velocity joint at a predetermined interval, and an injection hole in the jacket provided externally and an injection hole provided approximately perpendicular to the pedestal, the integrated type etc. An induction hardening device characterized by comprising means for cooling an end face of a quick joint.