# US 2018/0320737 A1 · Method for producing bearing ring and method for producing double row tapered roller bearing

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- Number: US 2018/0320737 A1
- Document ID: US20180320737A1
- Status: Published application
- Kind: A1
- Application number: 15/771,892
- Filed: 2016-10-12
- Published: 2018-11-08
- Earliest claimed: 2015-10-29
- Assignees: Ntn Corporation
- Applicants: Ntn Corporation
- Inventors: Michio HORI; Hideto TORISAWA; Hiroshi YUKI; Chikara OHKI; Kazuhiro YAGITA
- Web page: https://patentgrep.com/patent/US20180320737A1

## CPC

- C22C 38/02: containing silicon
- F16C 19/385: {with two rows, i.e. double-row tapered roller bearings}
- C21D 1/10: by electric induction
- C21D 1/22: Martempering
- C21D 1/25: Hardening, combined with annealing between 300 degrees Celsius and 600 degrees Celsius, i.e. heat refining ("Vergüten")
- C21D 1/28: Normalising
- C21D 6/002: {containing Cr (C21D6/004 takes precedence)}
- C21D 6/004: {containing Cr and Ni}
- C21D 7/06: by shot-peening or the like
- C21D 9/40: for rings; for bearing races
- C22C 38/00: Ferrous alloys, e.g. steel alloys (cast-iron alloys C22C37/00)
- C22C 38/04: containing manganese
- C22C 38/22: with molybdenum or tungsten
- C22C 38/44: with molybdenum or tungsten
- F16C 19/38: with two or more rows of rollers
- F16C 19/386: {in O-arrangement}
- F16C 33/585: {of raceways, e.g. ribs to guide the rollers}
- F16C 33/62: Selection of substances
- F16C 33/64: Special methods of manufacture
- F16C 43/04: Assembling rolling-contact bearings
- F03D 80/70: Bearing or lubricating arrangements
- F05B 2240/50: Bearings
- F16C 2204/64: Medium carbon steel, i.e. carbon content from 0.4 to 0,8 wt%
- F16C 2223/18: with induction hardening
- F16C 2360/31: Wind motors
- Y02P 10/25: Process efficiency
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- F03D: WIND MOTORS
- F05B: INDEXING SCHEME RELATING TO WIND, SPRING, WEIGHT, INERTIA OR LIKE MOTORS, TO MACHINES OR ENGINES FOR LIQUIDS COVERED BY SUBCLASSES F03B, F03D AND F03G
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A method for producing a bearing ring of a double row tapered roller bearing includes the steps of: preparing a formed body; forming a heated region; cooing; and removing. In the step of forming a heated region, an induction heating coil arranged to face part of the groove and induction-heating the fixated body is relatively rotated along the circumferential direction of the groove to form a heated region including the bottom surface of the groove and heated to a temperature of at least an Al point. In the cooling step, the whole of the heated region is simultaneously cooled to a temperature of not more than an Ms point. After the step of forming a heated region before the step of cooling, the method further includes the step of retaining the formed body in a state where heating is stopped.

## Claims

### Claim 1

A method for producing a bearing ring of a double row tapered roller bearing, comprising the steps of:
preparing a formed body constituted of steel and having an outer circumferential surface having an annular groove having a bottom surface to serve as a raceway surface of the bearing ring;
forming a heated region including the bottom surface of the groove and heated to a temperature of at least an Al point by relatively rotating along a circumferential direction of the groove an induction heating coil arranged to face part of the groove and induction-heating the formed body;
simultaneously cooling a whole of the heated region to a temperature of not more than an Ms point; and
retaining the formed body in a state where heating is stopped after the step of forming a heated region before the step of cooling,
in the step of forming a heated region, the induction heating coil being used which has a shape allowing a region of the coil facing the groove and contributing to heating the groove to be included in a single plane.

### Claim 2 (depends on 1)

The method for producing a bearing ring according to claim 1, in the step of preparing a formed body, the formed body including an excessive portion in which a region adjacent to the groove extends outwardly of a position which should be an outer circumferential surface of the bearing ring, the method further comprising the step of removing the excessive portion from the formed body after the step of cooling.

### Claim 3 (depends on 2)

The method for producing a bearing ring according to claim 2, wherein:
the formed body has an annular shape, and
in the step of preparing a formed body, the excessive portion of the formed body is annularly arranged so as to sandwich the groove in a direction of a central axis of the formed body.

### Claim 4 (depends on 3)

The method for producing a bearing ring according to claim 3, wherein in the step of preparing a formed body, an angle that the bottom surface of the groove of the formed body forms with the central axis is 40° or more and 50° or less.

### Claim 5 (depends on 1)

The method for producing a bearing ring according to claim 1, wherein a plurality of induction heating coils are arranged along the circumferential direction in the step of forming a heated region.

### Claim 6 (depends on 5)

The method for producing a bearing ring according to claim 5, wherein the plurality of induction heating coils are equally spaced along the circumferential direction in the step of forming a heated region.

### Claim 7 (depends on 1)

The method for producing a bearing ring according to claim 1, wherein the induction heating coil relatively rotates at least twice along the circumferential direction in the step of forming a heated region.

### Claim 8 (depends on 1)

The method for producing a bearing ring according to claim 1, wherein in the step of forming a heated region, the heated region has its temperature measured at a plurality of portions thereof.

### Claim 9 (depends on 1)

The method for producing a bearing ring according to claim 1, wherein in the step of preparing a formed body, the formed body is prepared which is constituted of steel containing at least 0.43 mass % and not more than 0.65 mass % of carbon, at least 0.15 mass % and not more than 0.35 mass % of silicon, at least 0.60 mass % and not more than 1.10 mass % of manganese, at least 0.30 mass % and not more than 1.20 mass % of chromium, and at least 0.15 mass % and not more than 0.75 mass % of molybdenum with the rest consisting of iron and an impurity.

### Claim 10 (depends on 1)

The method for producing a bearing ring according to claim 1, wherein in the step of preparing a formed body, the formed body is prepared which is constituted of steel containing at least 0.43 mass % and not more than 0.65 mass % of carbon, at least 0.15 mass % and not more than 0.35 mass % of silicon, at least 0.60 mass % and not more than 1.10 mass % of manganese, at least 0.30 mass % and not more than 1.20 mass % of chromium, at least 0.15 mass % and not more than 0.75 mass % of molybdenum, and at least 0.35 mass % and not more than 0.75 mass % of nickel with the rest consisting of iron and an impurity.

### Claim 11 (depends on 1)

The method for producing a bearing ring according to claim 1, further comprising the step of normalizing the formed body in advance of the step of forming a heated region.

### Claim 12 (depends on 11)

The method for producing a bearing ring according to claim 11, wherein in the step of normalizing, hard particles are sprayed to the formed body along with a gas to perform shot blasting while cooling the formed body.

### Claim 13 (depends on 1)

A method for producing a double row tapered roller bearing, comprising the steps of:
preparing a bearing ring;
preparing tapered rollers; and
assembling a double row tapered roller bearing by combining the bearing ring and the rollers,
the bearing ring being produced in the method for producing a bearing ring according to claim 1.