# US 9,434,209 B2 · Wheel bearing apparatus

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 9,434,209 B2
- Document ID: US9434209B2
- Status: Granted
- Kind: B2
- Application number: 14/447,708
- Filed: 2014-07-31
- Published: 2014-11-20
- Granted: 2016-09-06
- Earliest claimed: 2012-02-01
- Assignees: Ntn Corporation
- Applicants: NTN Corporation
- Inventors: Mitsuru Umekida
- Web page: https://patentgrep.com/patent/US9434209B2

## CPC

- B60B 27/0026: {of the radial type, e.g. splined key}
- B21J 9/025: {with rolling or wobbling dies}
- B21K 25/00: Uniting components to form integral members, e.g. turbine wheels and shafts, caulks with inserts, with or without shaping of the components (uniting by interference- or press-fitting B23P11/02, B21K19/02)
- B60B 27/0084: {caulking to fix inner race}
- C21D 1/06: Surface hardening
- C21D 9/32: for gear wheels, worm wheels, 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 38/02: containing silicon
- C22C 38/04: containing manganese
- C22C 38/06: containing aluminium
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- C22C 38/22: with molybdenum or tungsten
- F16C 35/063: Fixing them on the shaft (with interposition of an element F16C35/07)
- B60B 27/00: Hubs (non-metallic B60B5/00; of high resiliency B60B9/00)
- B60B 27/001: {with roller-bearings}
- B60B 27/0068: {the element being a sensor}
- B60B 27/0078: {characterised by the fixation of bearings}
- B60B 2310/54: Hardening
- B60B 2900/311: Rigidity or stiffness
- B60B 2900/321: Lifetime
- C21D 1/42: Induction heating
- F16C 19/386: {in O-arrangement}
- F16C 41/007: {Encoders, e.g. parts with a plurality of alternating magnetic poles}
- F16C 2326/02: Wheel hubs or castors
- Y02P 10/25: Process efficiency
- B60B: VEHICLE WHEELS (making wheels or wheel parts by rolling B21H1/00, by forging, hammering or pressing B21K1/28); CASTORS; AXLES FOR WHEELS OR CASTORS; INCREASING WHEEL ADHESION
- B21J: FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES (rolling of metal B21B; making particular products by forging or pressing B21K; cladding or plating B23K; finishing surfaces by hammering B23P9/04; compacting surfaces by blasting with particulate material B24C1/10; general features of presses, presses for consolidating scrap B30B; furnaces in general F27)
- B21K: MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS (making particular articles by working sheet metal without essentially removing material B21D; processing wire B21F; making pins, needles or nails B21G; making particular articles by rolling B21H; forging machines, pressing machines, hammering machines, in general B21J; making chains B21L; plating B23K)
- 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)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A wheel bearing apparatus has an outer member, an inner member including a wheel hub and at least one inner ring, and double row rolling elements freely rollably contained between the inner and outer raceway surfaces of the inner and outer members via cages. A hardened ring-shaped gear member is mounted on an end of a cylindrical portion of the wheel hub. The gear member is formed with a gear portion on its outer circumference and with a splined portion on its inner circumference. The splined portion engages a hub-splined portion formed on the outer circumference of the cylindrical portion of the wheel hub. A contacting surface of the gear member and a contacting surface of the inner ring that abut against each other are ground. The inner rings are axially immovably secured under a condition where a predetermined amount of a bearing pre-stress is applied to the inner rings via the gear member.

## Claims

### Claim 1

A wheel bearing apparatus comprising:
an outer member integrally formed with a body mounting flange on its outer circumference, the body mounting flange adapted to be mounted on a knuckle of a suspension apparatus, the outer member inner circumference includes double row outer raceway surfaces;
an inner member includes double row inner raceway surfaces, a wheel hub and at least one inner ring, the wheel hub is integrally formed with a wheel mounting flange on its one end, a cylindrical portion axially extends from the wheel mounting flange, the at least one inner ring is press-fit onto the cylindrical portion of the wheel hub via a predetermined interference, the at least one inner ring outer circumference is formed with one of the double row inner raceway surfaces that corresponds to one of the double row outer raceway surfaces of the outer member;
double row rolling elements are freely rollably contained between the inner and outer raceway surfaces of the inner and outer members, via cages;
a hardened ring-shaped gear member is mounted on an end of the cylindrical portion of the wheel hub, the gear member is formed with a gear portion on its outer circumference and with a splined portion on its inner circumference, the splined portion engages a hub-splined portion formed on the outer circumference of the cylindrical portion of the wheel hub;
a contacting surface of the gear member and a contacting surface of the at least one inner ring that abut against each other are ground to provide a desired roughness on the contacting surfaces to enable close contact and frictional resistance between the contacting surfaces to reduce torque on the splined portion; and
the at least one inner ring is axially immovably secured to the wheel hub under a condition where a predetermined amount of a bearing pre-stress is applied to the at least one inner ring, via the gear member.

### Claim 2 (depends on 1)

The wheel bearing apparatus of claim 1, wherein the surface roughness (Ra) of the contacting surface of the gear member contacting against the inner ring is set to 1.6 or less (Ra≦1.6).

### Claim 3 (depends on 1)

The wheel bearing apparatus of claim 1, wherein the inner rings are secured by a caulked portion formed by plastically deforming the end of the cylindrical portion of the wheel hub, and the caulked portion is kept as a non-hardened portion with a surface hardness after forging.

### Claim 4 (depends on 3)

The wheel bearing apparatus of claim 3, wherein a contacting width (W) between the gear member and the caulked portion is set to 1 mm or more.

### Claim 5 (depends on 1)

The wheel bearing apparatus of claim 1, wherein an external thread is formed on the end of the cylindrical portion of the wheel hub, and a securing nut is fastened on the external thread to secure the inner rings.

### Claim 6 (depends on 5)

The wheel bearing apparatus of claim 5, wherein a contacting width (W) between the gear member and the securing nut is set to 1 mm or more.

### Claim 7 (depends on 1)

The wheel bearing apparatus of claim 1, wherein the gear member is formed of steel including carbon of 0.15˜0.45% by weight (wt%), the gear member is hardened to its core by dip quenching, and the gear member has a surface hardness of 40 HRC or more.

### Claim 8 (depends on 1)

The wheel bearing apparatus of claim 1, wherein the gear member is formed of chrome molybdenum steel including Mo of 0.15˜0.3% by weight (wt%), a hardened layer is formed on a surface of the gear member by carburizing quenching, and the hardened layer has a surface hardness set to 40 HRC or more.

### Claim 9 (depends on 1)

The wheel bearing apparatus of claim 1, wherein a hardened layer having the surface hardness of 50˜64 HRC is formed on part of the hub-splined portion by high frequency induction hardening.