# US 10,371,172 B2 · Reduction of turbocharger core unbalance with balance washer

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- Number: US 10,371,172 B2
- Document ID: US10371172B2
- Status: Granted
- Kind: B2
- Application number: 14/429,369
- Filed: 2013-01-17
- Published: 2015-08-06
- Granted: 2019-08-06
- Earliest claimed: 2012-10-02
- Assignees: BorgWarner Inc.
- Applicants: BorgWarner Inc.
- Inventors: Denny King
- Web page: https://patentgrep.com/patent/US10371172B2

## CPC

- F04D 29/668: {damping or preventing mechanical vibrations}
- F01D 5/027: {Arrangements for balancing (for balancing rotating bodies in general F16F15/32; for compensating imbalance G01M1/36)}
- F04D 17/10: for compressing or evacuating
- F04D 29/266: {mounting compressor rotors on shafts}
- F04D 29/284: {for compressors}
- F04D 29/662: {Balancing of rotors (compensating imbalance G01M1/36)}
- F16B 43/00: Washers or equivalent devices; Other devices for supporting bolt-heads or nuts (circlips F16B21/18; {for indicating tensile load F16B31/02; forming a whole with the bolt or nut F16B33/00; locking bolts or nuts by means of a fixed plate or ring, or washer-like resilient plates F16B39/10, F16B39/24})
- F16F 15/34: Fastening arrangements therefor
- F01D 5/025: {Fixing blade carrying members on shafts (attachment of a member on a shaft in general F16D1/06; for non-positive displacement pumps F04D29/00)}
- F05D 2220/40: in turbochargers
- F16F 15/322: {the rotating body being a shaft (F16F15/34, F16F15/36 take precedence)}
- Y10T 29/49245: Vane type or other rotary, e.g., fan
- F04D: NON-POSITIVE-DISPLACEMENT PUMPS (engine fuel-injection pumps F02M; ion pumps H01J41/12; electrodynamic pumps H02K44/02)
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F16B: DEVICES FOR FASTENING OR SECURING CONSTRUCTIONAL ELEMENTS OR MACHINE PARTS TOGETHER, e.g. NAILS, BOLTS, CIRCLIPS, CLAMPS, CLIPS OR WEDGES; JOINTS OR JOINTING (couplings for transmitting rotation F16D)
- F16F: SPRINGS; SHOCK-ABSORBERS; MEANS FOR DAMPING VIBRATION
- F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Turbochargers operate at extremely high speed, so balance of the rotating core is of the utmost importance to turbocharger life. A special balancing washer is added to the clamping region between the compressor nut and the nose of the compressor wheel to aid in keeping the wheel, nut, and stub-shaft on the turbocharger axis and to thereby prevent introduction of core unbalance.

## Claims

### Claim 1

A rotating assembly, comprising
a shaft (52) with a turbine end and including a reduced diameter stub shaft (56) part with a threaded end,
a turbine wheel (51) rigidly connected to the turbine end of the shaft to form a shaft-and-wheel assembly (50),
a compressor wheel (20) held in position on the stub shaft (56) by the clamp load from a compressor nut (30) threaded onto said threaded end of the shaft, and
a balance washer (36, 37) provided between the nut and the compressor wheel, wherein the balance washer has a parallelism of ≤0.001″.

### Claim 2 (depends on 1)

The rotating assembly as in claim 1, wherein the balance washer has a parallelism of ≤0.0006″.

### Claim 3 (depends on 1)

The rotating assembly as in claim 1, wherein the balance washer has a parallelism of ≤0.0002″.

### Claim 4 (depends on 1)

The rotating assembly as in claim 1, wherein the balance washer has a surface roughness of Rz2 or less.

### Claim 5 (depends on 1)

The rotating assembly as in claim 1, wherein the balance washer (36, 37) is made of a material having a higher hardness than the material of the compressor wheel.

### Claim 6 (depends on 1)

The rotating assembly as in claim 1, wherein the compressor wheel (20) is made of aluminum or an aluminum alloy.

### Claim 7 (depends on 1)

The rotating assembly as in claim 1, wherein the compressor wheel (20) is made of titanium or a titanium alloy.

### Claim 8 (depends on 1)

The rotating assembly as in claim 1, wherein the compressor wheel (20) is made of a ferrous metal or ferrous alloy.

### Claim 9 (depends on 1)

The rotating assembly as in claim 1, wherein the washer is made of a polymer.

### Claim 10 (depends on 9)

The rotating assembly as in claim 9, wherein the polymer is Teflon.

### Claim 11

A rotating assembly, comprising
a shaft (52) with a turbine end and including a reduced diameter stub shaft (56) part with a threaded end,
a turbine wheel (51) rigidly connected to the turbine end of the shaft to form a shaft-and-wheel assembly (50),
a compressor wheel (20) held in position on the stub shaft (56) by a clamp load from a compressor nut (30) threaded onto said threaded end of the shaft, and
a balance washer (36, 37) provided between the nut and the compressor wheel, wherein the balance washer has a parallelism of ≤0.001″ and a thickness of 0.076 mm to 0.51 mm.

### Claim 12 (depends on 11)

The rotating assembly as in claim 11, wherein the balance washer has a thickness of 0.127 mm to 0.46 mm.

### Claim 13

A rotating assembly, comprising
a shaft (52) with a turbine end and including a reduced diameter stub shaft (56) part with a threaded end,
a turbine wheel (51) rigidly connected to the turbine end of the shaft to form a shaft-and-wheel assembly (50),
a compressor wheel (20) held in position on the stub shaft (56) by a clamp load from a compressor nut (30) threaded onto said threaded end of the shaft, and
a balance washer (36, 37) provided between the nut and the compressor wheel, wherein the balance washer has a parallelism of ≤0.001″ and a thickness of from 0.25 mm to 0.38 mm.