Reduction of turbocharger core unbalance with balance washer
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.
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″.
2. The rotating assembly as in claim 1 , wherein the balance washer has a parallelism of ≤0.0006″.
3. The rotating assembly as in claim 1 , wherein the balance washer has a parallelism of ≤0.0002″.
4. The rotating assembly as in claim 1 , wherein the balance washer has a surface roughness of Rz2 or less.
5. 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.
6. The rotating assembly as in claim 1 , wherein the compressor wheel ( 20 ) is made of aluminum or an aluminum alloy.
7. The rotating assembly as in claim 1 , wherein the compressor wheel ( 20 ) is made of titanium or a titanium alloy.
8. The rotating assembly as in claim 1 , wherein the compressor wheel ( 20 ) is made of a ferrous metal or ferrous alloy.
9. The rotating assembly as in claim 1 , wherein the washer is made of a polymer.
10. The rotating assembly as in claim 9 , wherein the polymer is Teflon.
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.
12. The rotating assembly as in claim 11 , wherein the balance washer has a thickness of 0.127 mm to 0.46 mm.
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.