Heat treatment method for cam piece

Patent metadata

Field	Value
Publication number	US-10602571-B2
Application number	US-201715461653-A
Country	US
Kind code	B2
Filing date	Mar 17, 2017
Priority date	Mar 18, 2016
Publication date	Mar 24, 2020
Grant date	Mar 24, 2020

Abstract

Provided is a heat treatment method for a cam piece, and the cam piece has an insertion hole into which a cam shaft is inserted, a base portion configuring a base circle of a cam, and a nose portion configuring a cam ridge. The heat treatment method for the cam piece includes: a first step of using a jig formed into a shape having a cavity, the jig being inserted into the insertion hole such that the cavity is located between an inner circumferential surface of the nose portion of the cam piece and a central axis of the jig; and a second step of heating the cam piece from an outer circumferential surface side by high-frequency induction heating in a state in which the jig is inserted in the insertion hole of the cam piece.

First claim

What is claimed is:

1. A heat treatment method for a cam piece, the cam piece configuring an assembly-type cam shaft, the cam piece including an insertion hole into which a shaft configuring the assembly-type cam shaft is inserted, a base portion configuring a base circle of a cam, and a nose portion having a greater wall thickness from the insertion hole to an outer circumferential surface than that of the base portion, the nose portion configuring a cam ridge, the heat treatment method comprising:
a first step of using a jig formed into a shape having a cavity inside a cylinder of the jig, the cavity being located between a central axis and the outer circumferential surface, the jig being inserted into the insertion hole of the cam piece in such a manner that the cavity is located between an inner circumferential surface in the nose portion of the cam piece and the central axis of the jig, and the jig comes into contact with the inner circumferential surface that defines the insertion hole; and
a second step of heating the cam piece from the outer circumferential surface by high-frequency induction heating in a state in which the jig is inserted in the insertion hole of the cam piece.

2. The heat treatment method for the cam piece according to claim 1 , wherein in the second step, the high-frequency induction heating is started in a state in which the cavity includes a liquid coolant.

3. The heat treatment method for the cam piece according to claim 2 , further comprising
a third step of cooling the cam piece and the jig using a quenching liquid in a state in which the jig is inserted in the insertion hole of the cam piece heated via the second step, wherein the liquid coolant is the quenching liquid.

4. The heat treatment method for the cam piece according to claim 1 , further comprising
a third step of cooling the cam piece and the jig using a quenching liquid in a state in which the jig is inserted in the insertion hole of the cam piece heated via the second step.

5. The heat treatment method for the cam piece according to claim 1 , wherein a top surface of the jig includes a plate that covers an opening of the cavity.

6. A heat treatment method for a cam piece, the cam piece configuring an assembly-type cam shaft, the cam piece including an insertion hole into which a shaft configuring the assembly-type cam shaft is inserted, a base portion configuring a base circle of a cam, and a nose portion having a greater wall thickness from the insertion hole to an outer circumferential surface than that of the base portion, the nose portion configuring a cam ridge, the heat treatment method comprising:
a first step of using a jig formed into a shape having a cutout recessed radially inward at a part of a cylinder of the jig, the jig being inserted into the insertion hole of the cam piece in such a manner that an inner circumferential surface in the nose portion of the cam piece faces the cutout of the jig, and the jig comes into contact with the inner circumferential surface that defines the insertion hole; and
a second step of heating the cam piece from the outer circumferential surface by high-frequency induction heating in a state in which the jig is inserted in the insertion hole of the cam piece.

7. The heat treatment method for the cam piece according to claim 6 , further comprising
a third step of cooling the cam piece and the jig using a quenching liquid in a state in which the jig is inserted in the insertion hole of the cam piece heated via the second step.

8. The heat treatment method for the cam piece according to claim 6 , wherein a top surface of the jig includes a plate that covers the cutout from the top surface of the jig.

9. The heat treatment method for the cam piece according to claim 6 , wherein the cutout of the jig has a circle-sector shape in a cross section orthogonal to a central axis of the jig.

10. The heat treatment method for the cam piece according to claim 6 , wherein a cross section of the cutout of the jig that is orthogonal to a central axis of the jig has a central angle of smaller than 180°.

Assignees

• Toyota Motor Co Ltd

Inventors

• Tateishi Hiroki

Classifications

• H05B6/102

  the metal pieces being rotated while induction heated · CPC title

• F01L2303/00

  Manufacturing of components used in valve arrangements · CPC title

• F01L2301/00

  Using particular materials · CPC title

• F01L2001/0471

  Assembled camshafts · CPC title

• F01L1/042

  Cam discs · CPC title