Molding device for manufacturing cylindrical rolling body, manufacturing method for cylindrical rolling body, manufacturing method for rolling bearing, manufacturing method for vehicle, and manufacturing method for mechanical apparatus

Patent metadata

Field	Value
Publication number	US-10525522-B2
Application number	US-201816305410-A
Country	US
Kind code	B2
Filing date	Apr 17, 2018
Priority date	Jul 28, 2017
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

With respect to the manufacture of cylindrical rolling bodies, excess material on an outside section in the radial direction and recesses in both end surfaces in the axial direction are not generated as much as possible in the intermediate material that is removed from a molding device for performing compression molding. Annular concave sections 27 are provided on the inner-circumferential surfaces 20a of molding concave sections 19a provided in a stationary-side mold 17a and a movable-side mold 18a. The stationary-side mold 17a and the movable-side mold 18a are brought close to each other in the axial direction while compressing the intermediate material 23 in a state in which both side sections in the axial direction of the intermediate material 23 are inserted into the molding concave sections 19a. At this time, a part of the material of the intermediate material 23 is made to enter inside the annular concave sections 27, and undercut sections 32 are formed on the outer side in the radial direction of a compression-molded intermediate material 23b. After that, when removing both side sections in the axial direction of the intermediate material 23b from the inside of the molding concave sections 19a in the axial direction, the undercut sections 32 are drawn through or handled by stepped sections 29 existing at the end sections in the axial direction of the annular concave sections 27.

First claim

The invention claimed is:

1. A manufacturing method for a cylindrical rolling body using a molding device for manufacturing a cylindrical rolling body;
the molding device for manufacturing a cylindrical rolling body comprising a pair of molds having one side surfaces in an axial direction and arranged so as to be capable of relative displacement in the axial direction with the one side surfaces in the axial direction facing each other;
the pair of molds having bottomed molding concave sections opening at positions on the one side surfaces in the axial direction facing each other and each having an inner surface; and
the inner surface of each of the molding concave sections having an inner-circumferential surface, a bottom surface, and an annular corner R section having an arc-shaped cross section and connecting the inner-circumferential surface and the bottom surface;
the manufacturing method comprising:
preparing a cylindrical intermediate material having a dimension in the axial direction that is larger than and a diameter dimension that is a smaller than those of a cylindrical rolling body to be manufactured;
inserting both side sections in the axial direction of the intermediate material inside the molding concave sections of the pair of molds respectively; and compressing the intermediate material by bringing the pair of molds close to each other in the axial direction and plastically deforming the intermediate material; to compression mold the intermediate material; and
removing the both side sections in the axial direction of the intermediate material from the inside of the molding concave sections of the pair of molds in the axial direction;
wherein at least one mold of the pair of molds has an annular concave section recessed outward in a radial direction on the inner-circumferential surface of the molding concave section;
when compression molding the intermediate material, a part of the material of the intermediate material being made to enter into the inside of the annular concave section, forming an undercut section in a part of the outside section in the radial direction of the intermediate material; and
when removing the both side sections in the axial direction of the intermediate material, the undercut section being reduced in diameter by drawing the undercut section through a stepped section existing on an end section in the axial direction of the annular concave section.

2. The manufacturing method for a cylindrical rolling body according to claim 1 , wherein
each of the pair of molds comprises a die and a knockout pin that are combined so as to be capable of relative displacement in the axial direction;
at least a central section of the bottom surface of the inner surface of the molding concave section is configured by a tip-end section of the knockout pin; and the remaining portion of the inner surface of the molding concave section is formed in the die; and
the operation of removing the both side sections in the axial direction of the intermediate material from the inside of the molding concave sections of the pair of molds in the axial direction is performed based on causing the tip-end section of the knockout pin to protrude inside the molding concave section.

3. A manufacturing method for a rolling bearing that comprises cylindrical rolling bodies, wherein the cylindrical rolling bodies are manufactured by the manufacturing method according to claim 1 .

4. A manufacturing method for a vehicle in which a rolling bearing that comprises cylindrical rolling bodies is assembled, wherein the cylindrical rolling bodies are manufactured by the manufacturing method according to claim 1 .

5. A manufacturing method for a mechanical apparatus in which a rolling bearing that comprises cylindrical rolling bodies is included, wherein the cylindrical rolling bodies are manufactured by the manufacturing method according to claim 1 .

6. The manufacturing method for a cylindrical rolling body according to claim 1 , wherein, in the process of plastically deforming the intermediate material, the intermediate material is compressed in a state in which outer-circumferential edge sections of both end edge sections in the axial direction of the intermediate material are respectively brought in contact with the corner R sections of the molding concave sections of the pair of molds.

Assignees

• Nsk Ltd

Inventors

• Yasuda Yuu
• Watanabe Mizuki
• Mizushima Yuuki

Classifications

• B21J5/02 Primary

  Die forging; Trimming by making use of special dies {; Punching during forging} · CPC title

• F16C33/34

  Rollers; Needles · CPC title

• B21K1/02

  balls, rolls, or rollers, e.g. for bearings · CPC title

• B21J13/02 Primary

  Dies or mountings therefor · CPC title

• B21J5/06

  for performing particular operations · CPC title