JPS6332128Y2 - - Google Patents

Description

[Detailed description of the invention] (a) Industrial application field The present invention relates to an induction hardening jig used for hardening a crankshaft.

(b) Conventional technology When hardening a crankshaft, only the cylindrical body of the journal and pin parts that make up the crankshaft were surface hardened (see Figure 1). In order to improve strength, especially fatigue strength, not only the body 111 but also R
A continuous hardened surface layer 114 including the portion 112 and the fillet portion 113 is formed (hereinafter referred to as R).
A method called quenching (hardening) has been adopted.

The R section and fillet section of the crankshaft, which are to be surface hardened, have some parts that have to be made thin due to the design. It will no longer be available.

(C) Purpose The purpose of the present invention is to provide an induction hardening jig that can perform R hardening without causing quench cracks on crankshafts and the like where the vicinity of the R portion is constructed with a special thin wall. There is.

(D) Structure The present invention includes a block that grips the pin portion of the crankshaft for fixing the jig, and a loss structure having a substantially crescent-shaped abutment portion that abuts the outside of the thin R portion of the crankshaft. This jig for induction hardening is characterized by comprising a connecting body that connects the blocks in a substantially L-shape so that the distance between the blocks and the loss structure can be freely adjusted.

(F) Embodiment FIG. 2 is a perspective view showing an embodiment of the induction hardening jig according to the present invention.

Reference numerals 30 and 31 denote blocks having semicircular hollowed out portions facing each other and having diameters approximately equal to the diameter of the pin portion. Numeral 32 is a bolt screwed into the block 31 on both sides of the block, and by attaching and detaching the bolt 32, the blocks 30 and 31 are screwed together.
The hollowed out part contains the pin part of the crankshaft, and the jig is fixed to the pin part of the crankshaft.

42 is a loss structure, and this loss structure 4
2 includes a dowel 40 made of, for example, a copper alloy and having a substantially crescent shape, and a block 41 fixed to the dot 40.

Numeral 33 is a bolt as a connecting member fixed to the lower part of the block 31, and the bolt 33 is screwed into the block 41 so that the distance between the blocks 31 and 41 can be adjusted by rotating the nut 34. ing. The loss structure 42 and the blocks 30, 31 are connected in a substantially L-shape.

Fig. 3 shows the induction hardening jig shown in Fig. 2 used to prevent quenching cracks occurring near the lower left circular part of the journal part 11 of the crankshaft (hereinafter referred to as the thin R part). FIG.

First, block 3 is attached to pin portion 12 of crankshaft 10.
The block 31 and the block 41 are fixed by gripping them at the ends 30 and 31, and the distance between the block 31 and the block 41 is adjusted by rotating the nut 34 so that the abutment 40 abuts against the surface of the outer side 16 of the thin wall R portion.

On the other hand, 20 is a semi-loop type induction hardening coil that extends over the journal portion at a predetermined distance, and a high frequency current is applied to this during hardening. In addition, 13 indicates the journal part 11 and the pin part 1.
This is a connecting part that connects the two.

The procedure for R-hardening the journal part of the crankshaft using the induction hardening jig of the present invention will be described below.

First, a high-frequency current is applied to the high-frequency hardening coil 20, and the crankshaft 10 is rotated about the shaft to generate a high-frequency induced current generated by the high-frequency heating coil 20 installed on the upper surface of the journal part 11 via a spacer. A predetermined surface of the journal portion 11 is heated to a predetermined temperature.

Next, the induction hardening coil 20 is removed upward, and the crankshaft 10 is moved as if it revolves, and is immersed in a separate hardening tank (not shown) for rapid cooling.

After cooling, the crankshaft rotates further and is removed from the quenching tank.

(F) Effect As shown in Fig. 3, the thin R at the end of the connecting part 13
This part is particularly thin compared to other parts, so in the conventional method, it is heated under the same conditions as other parts, so not only the surface but also the inside is heated, which causes the problems mentioned above. It was occurring, but
In the present invention, since the stopper 40 is in contact with the outside of the connection part, the high frequency current also flows through the stopper 40, and
Since the heat generated in the thin R portion escapes to the contact side, heating of this portion is prevented.

In addition, during the rapid cooling for hardening after heating, the refrigerant directly contacts only the surface that needs to be hardened, and the back side of this thin R part is blocked by the pad 40, so the thin R part is rapidly cooled. Not done.

Therefore, according to this invention, quench cracking of the thin R portion can be prevented.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the prior art, and FIG. 2 is a perspective view showing an embodiment of the induction hardening jig according to the present invention.
FIG. 3 is an explanatory diagram of R hardening using the induction hardening jig shown in FIG. 2. 10...crankshaft, 30, 31...block, 40...money.

Claims (1)

[Scope of utility model registration request] A block that grips the pin portion of the crankshaft for fixing the jig and a loss structure having a substantially crescent-shaped abutment portion that abuts the outside of the thin R portion of the crankshaft are connected in a substantially L-shape. . A jig for induction hardening, comprising: a connecting body that connects the block and the loss structure so that the distance between them can be freely adjusted.