# US 11,306,776 B2 · Double-row self-aligning roller bearing

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- Number: US 11,306,776 B2
- Document ID: US11306776B2
- Status: Granted
- Kind: B2
- Application number: 17/071,368
- Filed: 2020-10-15
- Published: 2021-01-28
- Granted: 2022-04-19
- Earliest claimed: 2018-04-20
- Assignees: Ntn Corporation
- Applicants: Ntn Corporation
- Inventors: Kazumasa Seko; Michio Hori; Yasuyuki Inoue; Takashi Yamamoto; Masaki Nakanishi
- Web page: https://patentgrep.com/patent/US11306776B2

## CPC

- F16C 23/086: {forming a track for rolling elements}
- F16C 25/08: self-adjusting
- F03D 80/70: Bearing or lubricating arrangements
- F16C 19/38: with two or more rows of rollers
- F16C 19/385: {with two rows, i.e. double-row tapered roller bearings}
- F16C 19/505: {with the diameter of the rolling elements of one row differing from the diameter of those of another row}
- F16C 23/08: self-adjusting
- F16C 33/36: with bearing-surfaces other than cylindrical, e.g. tapered; with grooves in the bearing surfaces
- F16C 2206/04: Diamond like carbon [DLC]
- F16C 2240/34: Contact angles
- F16C 2240/54: Surface roughness
- F16C 2240/60: Thickness, e.g. thickness of coatings
- F16C 2300/14: Large applications, e.g. bearings having an inner diameter exceeding 500 mm
- F16C 2360/31: Wind motors
- Y02E 10/72: Wind turbines with rotation axis in wind direction
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F03D: WIND MOTORS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Provided is a double-row self-aligning roller bearing including: an inner ring; an outer ring having a spherical raceway surface; and rollers arranged in two rows and interposed between the inner ring and the outer ring, wherein a ratio of a contact angle θ1 in one row to a contact angle θ2 in the other row falls within a range of 0.25≤θ1/θ2≤0.5, and a ratio of distance B1 in a bearing width direction from an end face of the bearing on a side of the one of the rows to an intersection of two lines of action defining the contact angles of the two rows, relative to a distance B2 in the bearing width direction from an end face of the bearing on a side of the other of the rows to the intersection falls within a range of 0.5≤B1/B2≤0.6.

## Claims

### Claim 1

A double-row self-aligning roller bearing comprising:
an inner ring;
an outer ring having a spherical raceway surface; and
a plurality of rollers arranged in two rows in a bearing width direction and interposed between the inner ring and the outer ring, each of the rollers in the two rows having an outer peripheral surface having a cross-sectional shape matching the raceway surface of the outer ring,
wherein
a ratio of a contact angle θ1 of the rollers in one of the rows to a contact angle θ2 of the rollers in the other of the rows falls within a range of 0.25≤θ1/θ2≤0.5, and
a ratio of a distance B1 in the bearing width direction from an end face of the bearing on a side of the one of the rows to an intersection of two lines of action defining the contact angles of the two rows, relative to a distance B2 in the bearing width direction from an end face of the bearing on a side of the other of the rows to the intersection falls within a range of 0.5≤B1/B2≤0.6.

### Claim 2 (depends on 1)

The double-row self-aligning roller bearing as claimed in claim 1, wherein a ratio of a length L1 of the rollers in the one of the rows to a length L2 of the rollers in the other of the rows falls within a range of 0.9≤L1/L2≤1.0.

### Claim 3 (depends on 1)

The double-row self-aligning roller bearing as claimed in claim 1, wherein an inclination angle β2 of a retainer that retains the rollers in the other of the rows has a relation, relative to a roller maximum diameter angle α2 that is an inclination angle of the rollers in the other of the rows at a point where each of the rollers in the other of the rows has a maximum diameter, expressed by an inequation: 0≤β2≤α2.

### Claim 4 (depends on 1)

The double-row self-aligning roller bearing as claimed in claim 1, wherein each of the rollers has an outer peripheral surface coated with a DLC coating having a multi-layered structure;
the DLC coating has a film thickness of 2.0 μm or greater;
a base material of each of the rollers has a surface roughness of Ra≤0.3 and a root-mean-square gradient RΔq≤0.05 on an outer surface of the base material; and
the DLC coating having the multi-layered structure includes layers each having a film hardness, the film hardness stepwisely increasing toward an external-side layer.

### Claim 5 (depends on 1)

The double-row self-aligning roller bearing as claimed in claim 1, wherein the double-row self-aligning roller bearing is used for supporting a main shaft of a wind turbine generator.