JPH0225414B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a heat treatment jig, and more particularly to a heat treatment jig for reducing heat treatment deformation of a ring-shaped component.

Conventionally, in induction hardening of a ring gear, a ring gear 3 is attached to a jig 1 as shown in Fig. 1, and the ring gear 3 is inserted into a coil 2 through which a high-frequency current is flowing, and a high-frequency magnetic field is applied to its surface. , hardening and quenching is performed. For this reason, when the ring gear 3 is heated, the receiving surface A of the ring gear 3, that is,
Heat flows to the top surface of the jig 1, creating a temperature difference between the receiving surface A of the ring gear 3 and the top surface B on the opposite side.
As a result, the quenching strain in the portion of the ring gear 3 close to the receiving jig becomes extremely large.

Also, when the ring gear is heated, φD increases by 100 to 300μ.
When expanded and quenched, the inner diameter φD shrinks significantly (150 to 250μ) due to the lack of rigidity in the unhardened portion. Because the amount of inner diameter shrinkage is large, the outer diameter φd of the ring gear receiving jig 1 is determined by taking into account the amount of quenching shrinkage, and the inner diameter of the ring gear and the outer diameter of the receiving jig before quenching and during heating are determined. The gap 4 becomes considerably larger. Therefore, when heating and hardening the ring gear, the ring gear is hardened while being rotated, which causes misalignment, resulting in temperature unevenness in the surface hardened portion, or uneven cooling, resulting in large hardening distortions.

An object of the present invention is to provide a heat treatment jig that eliminates the drawbacks of the prior art described above.

In order to minimize heat treatment deformation, the heat treatment jig of the present invention changes the way the ring-shaped material to be treated is received from a surface support to a point support to limit the outflow of heat as much as possible.
The flow of heat from the hardened surface area is made uniform to suppress shape deformation, and a plug is inserted into the inner wall of the material to be treated to suppress the amount of shrinkage of the inner diameter of the material to be treated. The inner wall of the material to be treated is supported by a presser jig that is supported by the presser, thereby preventing the material from being misaligned.

Embodiments of the present invention will be described with reference to the drawings.

In FIG. 2, the jig main body 1 has a disc-shaped flange 1a, and a plurality of pillar-shaped support members 11 each having a tip are fixedly installed on the upper surface of the flange along the periphery of the flange. .

The support member 11 is attached to the upper surface of the jig main body 1 integrally by welding or the like or removably by bolting or the like, extends upward from the upper surface, preferably vertically upward, and substantially horizontally supports the material 3 to be treated. It has a pointed end at the upper end for point support, and three of them are arranged at appropriate intervals around the vertical axis of the jig main body 1, preferably at equal intervals on the same circumference. Geometrically, three points determine one plane, so supporting member 1
In theory, 3 pieces of 1 should be enough, but in case the tip gets worn out or the sharp tip gets damaged or deformed as you use it, you need 4 or more pieces in case you can't keep the support plane horizontal. It can be done.
In addition, although it is theoretically good for the tip of the support member 11 to be sharp so as to make a precise point contact, in reality, it is preferable to make a surface contact over a certain narrow area. From the viewpoint of durability, it is desirable that the support be supported at a certain point, and therefore, in this specification, the term "substantially supported at a point" includes support over such a narrow area.

The plug 12 is attached to the upper surface of the jig main body 1 integrally by welding or the like or detachably by screwing or the like, and extends upward from the upper surface.
The upper part of the support member 11 is arranged at the center of the inner side of the support member 11, which is arranged on the same axis as It has an outer circumferential surface 12a positioned corresponding to the inner wall of the material 3 and abutting against the inner diameter of the material 3 to limit shrinkage.

The cylinder 18 is fixed to the plug 12 by a stationary member 18a so as not to move relative to the plug 12, and is arranged above the plug 12, opposite the plug 12, and coaxially with the plug 12. It has an upper end plate 19 and a lower end plate 20 having a through hole in the center having the same axis as the axis.

A collar 16 is provided on the rod 15 that communicates the through holes of the upper end plate 19 and the lower end plate 20, and the upper end plate 19
The rod 15 is always urged downward by a spring 14 interposed between the flange 16 and the flange 16.

The plurality of holding jigs 13 are positioned correspondingly within the notch of the plug 12 and have surfaces that come into contact with the inner wall of the material to be treated 3.

The lever 17 is connected to the rod 1 at one end.
5, and the other end is pivotally connected to the inside of the presser jig 13,
The lower edge of the lever 17 rests on the upper edge of the plug 12. As a result, the holding jig 13 is urged in the radial direction within the notch 12a.

Next, the effect will be explained. First, the ring-shaped material to be processed 3 is inserted from the cylinder 18 side, then the rod 15 is lifted upwards, the holding jig 13 is brought into contact with the inner wall of the material to be processed 3, and the rod 15 is released. The workpiece 3 is set on the jig by the biasing force of the spring 14.

When the lever 17 and rod 15 move downward due to the bias of the spring 14, the lower surface of the lever 17 is supported by the upper edge of the plug 12.
The other end of the lever 17 and the holding jig 13 are pushed outward, and as a result, the holding jig 13 is constantly pressed against the inner wall of the material to be processed. Therefore, the holding jig 13 automatically centers the material 3 to be processed, and no misalignment of the center occurs when the material 3 to be processed expands due to heating or contracts due to cooling. That is, when the material to be treated 3 is heated, it expands as shown by the broken line in FIG. It follows and is fixed.
Also, during quenching, the entire material to be treated contracts, and at that time, the holding jig 13, lever 17, rod 15, and piston 16 move in the heating and reaction direction, compressing the spring 14 upward, Due to this reaction, the holding jig 13 is constantly pressed against the inner wall of the material 3 to be processed. However, the amount of inward movement is determined by the outer diameter of the plug 12, and cannot be smaller than that diameter.

Since the support member 11 that supports the material to be treated 3 has a relatively sharp tip, the amount of heat escaping from the material to be treated 3 to the support member 11 is extremely small, unlike conventional surface contact. Compared to the temperature difference (A, B), the temperature difference between the lower surface A' and the upper surface B' of the workpiece 3 is small (see Figure 4), and therefore the amount of deformation due to heat treatment is about one-third of that of the conventional method. descend.

As described above, the present invention supports the lower surface of the material to be treated in a substantially point-supported state, and the inner wall of the material to be treated is supported by the outer periphery of the plug and the elastically supported holding jig. Therefore, during quenching,
It is possible to prevent misalignment of the material to be treated, and also to prevent uneven temperature or cooling of the surface hardened portion, thereby making it possible to minimize quenching distortion.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the positional relationship between a conventional heat treatment jig and a material to be treated. FIG. 2 is a partial vertical sectional view showing the heat treatment jig of the present invention, and also shows the positional relationship with the material to be treated. FIG. 3 is a schematic diagram showing the expansion when the material to be treated is heated. Fourth
The figure is a graph of temperature measurement data showing the time course of the relationship between the temperature of the upper surface and the temperature of the lower surface of the workpieces heat-treated using the heat treatment jig of the present invention and the conventional heat treatment jig, respectively. It is. DESCRIPTION OF SYMBOLS 1... Jig main body, 3... Processed material, 11... Support member, 12... Plug, 13... Holding jig, 1
4... Spring, 15... Rod, 16... Piston, 17... Lever, 18... Cylinder,
19... Upper end plate, 20... Lower end plate, A... Lower surface of the material to be treated, B... Upper surface of the material to be treated.

Claims (1)

[Claims] 1. A plug for inserting and inserting a ring-shaped material to be treated, a plurality of support members located around the plug and substantially supporting the material to be treated, and a radial direction support member provided on the plug. A heat treatment jig comprising a holding jig inserted into an extending notch so as to be movable back and forth and urged in a radial direction so as to come into contact with an inner wall of the material to be treated.