# US 2014/0155210 A1 · Pulley apparatus

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- Number: US 2014/0155210 A1
- Document ID: US20140155210A1
- Status: Published application
- Kind: A1
- Application number: 13/696,078
- Filed: 2012-06-27
- Published: 2014-06-05
- Earliest claimed: 2011-06-30
- Assignees: Nsk Ltd.
- Inventors: Tomoya Ichikawa; Minoru Tahara
- Web page: https://patentgrep.com/patent/US20140155210A1

## CPC

- F16H 55/38: Means or measures for increasing adhesion
- F16C 33/581: {integral with other parts, e.g. with housings or machine elements such as shafts or gear wheels}
- F16C 33/583: {Details of specific parts of races}
- F16C 33/586: {outside the space between the races, e.g. end faces or bore of inner ring}
- F16C 35/067: Fixing them in a housing (with interposition of an element F16C35/07)
- F16H 55/36: Pulleys (with features essential for adjustment F16H55/52)
- F16H 55/48: manufactured exclusively or in part of non-metallic material, e.g. plastics (F16H55/38, F16H55/42, F16H55/46 take precedence)
- F16C 19/06: with a single row or balls
- F16C 2240/42: Groove sizes
- F16C 2361/63: Gears with belts and pulleys
- F16H 2200/0078: the gear ratio comprising twelve or more forward speeds
- F16H: GEARING
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS

## Abstract

Construction is achieved by which it is possible definitely prevent the occurrence of creep between a pulley 2b and an outer ring 7f. Trapezoidal shaped concave sections are formed such that the angle of intersection θ between the inside surfaces 23 on both sides of each concave section 17a of knurling 19a of the outer ring 7f is within the range 45°≦θ≦120°. Moreover, the depth h in the radial direction of the concave sections 17a and the diameter D of the circumscribed circle of the tip end surfaces 22 of the convex sections 18a are regulated so as to satisfy the relationship 0.004 D≦h≦0.015 D, and the length L in the circumferential direction of the bottom surface 21 of the concave sections 17a is regulated within the range 0.01 D≦L≦0.03 D.

## Claims

### Claim 1

A pulley apparatus, comprising:
a rolling bearing having an inner ring that has an inner ring raceway around the outer circumferential surface thereof, an outer ring that has an outer ring raceway around the inner circumferential surface thereof, and a plurality of rolling elements that are provided between the inner ring raceway and the outer ring raceway; and
a pulley that has an outer circumferential surface around which a belt is placed, and an inner circumferential surface that is fitted around the outer circumferential surface of the outer ring; wherein
at least one locking groove is provided around part in the axial direction of the outer circumferential surface of the outer ring, the locking groove having a width that is within the range of 1/20 to ½ the width of the outer ring;
knurling is formed on the bottom surface of this locking groove by a knurling process such that concave sections and convex sections that extend in the width direction of the knurling are alternately arranged around the entire circumference; each of these concave sections comprising a bottom surface and two inside surfaces on both sides in the circumferential direction of the bottom surface and that are continuous with the tip end surfaces of the adjacent convex sections; these concave sections having a trapezoidal shape by regulating the angle of intersection between the inside surfaces within the range 45° to 120°; and furthermore, the diameter D of the circumscribed circle of the tip end surface of the convex section, the depth h in the radial direction of the concave sections, and the length L in the circumferential direction of the bottom surface of the concave sections satisfy the relationship 0.004 D≦h≦0.015 D, and 0.01 D≦L≦0.03 D; and
a plurality of trapezoidal shaped protrusions that extend in the width direction and that engage with the concave sections are formed around part in the axial direction of the inner circumferential surface of the pulley.

### Claim 2 (depends on 1)

The pulley apparatus according to claim 1, wherein
the pulley is fastened to the outer circumferential surface of the outer ring by injection molding, and the protrusions are formed at the same time as this injection molding by molten resin of the pulley being filled in the locking groove and hardening.

### Claim 3 (depends on 1)

The pulley apparatus according to claim 1, wherein
the concave sections and convex sections of the knurling are provided so as to be inclined with respect to the axial direction.

### Claim 4

A pulley apparatus, comprising:
a rolling bearing having an inner ring that has an inner ring raceway around the outer circumferential surface thereof, an outer ring that has an outer ring raceway around the inner circumferential surface thereof, and a plurality of rolling elements that are provided between the inner ring raceway and the outer ring raceway; and
a pulley that has an outer circumferential surface around which a belt is placed, and an inner circumferential surface that is fitted around the outer circumferential surface of the outer ring; wherein
at least one locking groove is provided around part in the axial direction of the outer circumferential surface of the outer ring, the locking groove having a width that is within the range of 1/20 to ½ the width of the outer ring;
knurling is formed on the bottom surface of this locking groove by a knurling process such that concave sections and convex sections that extend in the width direction and in an inclined state with respect to the axial direction are alternately arranged around the entire circumference; each of these concave sections comprising a bottom surface and two inside surfaces on both sides in the circumferential direction of the bottom surface and that are continuous with the tip end surfaces of the adjacent convex sections; these concave sections having a trapezoidal shape; and
a plurality of trapezoidal shaped protrusions that extend in the width direction and in an inclined state with respect to the axial direction and that engage with the concave sections are formed around part in the axial direction of the inner circumferential surface of the pulley.

### Claim 5 (depends on 4)

The pulley apparatus according to claim 4, wherein
the pulley is fastened to the outer circumferential surface of the outer ring by injection molding, and the protrusions are formed at the same time as this injection molding by molten resin of the pulley being filled in the locking groove and hardening.

### Claim 6 (depends on 3)

The pulley apparatus according to claim 3, wherein
locking grooves are formed in two locations in the axial direction of the outer circumferential surface of the outer ring; and the concave sections and convex sections of the knurling that is formed in the bottom surfaces of these locking grooves are provided in a state so as to incline at the same angle with respect to the axial direction in opposite directions from each other.

### Claim 7 (depends on 4)

The pulley apparatus according to claim 4, wherein
locking grooves are formed in two locations in the axial direction of the outer circumferential surface of the outer ring; and the concave sections and convex sections of the knurling that is formed in the bottom surfaces of these locking grooves are provided in a state so as to incline at the same angle with respect to the axial direction in opposite directions from each other.