Alternator rings and cylindrical commutators made of a sintered copper-graphite composite material
First Claim
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1. A rotating element of an electrical machine, whereinsaid element comprises one or more rotating electrical contact parts,said rotating element having an axis of symmetry, and whereineach said contact part is made of a sintered copper-graphite composite material containing between 90 and 98% copper or copper alloy by weight,said graphite being in the form of flakes,said flakes being oriented with respect to said axis of symmetry such that the main axis P of more than 50% of said graphite flakes is inclined at less than 45°
- with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
/rho ⊥
being greater than 1.2 and the ratio R of bending strength R ∥
/R ⊥
being less than 0.8, where ∥
designates the direction parallel to said axis of symmetry and ⊥
the perpendicular direction,said composite having a specific gravity of between 6.5 and 8.5.
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Abstract
The invention relates to a rotating element of an electrical machine, rotating electrical contact parts and electrical machines containing these devices.
14 Citations
25 Claims
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1. A rotating element of an electrical machine, wherein
said element comprises one or more rotating electrical contact parts, said rotating element having an axis of symmetry, and wherein each said contact part is made of a sintered copper-graphite composite material containing between 90 and 98% copper or copper alloy by weight, said graphite being in the form of flakes, said flakes being oriented with respect to said axis of symmetry such that the main axis P of more than 50% of said graphite flakes is inclined at less than 45° - with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
/rho ⊥
being greater than 1.2 and the ratio R of bending strength R ∥
/R ⊥
being less than 0.8, where ∥
designates the direction parallel to said axis of symmetry and ⊥
the perpendicular direction,said composite having a specific gravity of between 6.5 and 8.5. - View Dependent Claims (2, 3)
- with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
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4. Manufacturing process for a rotating electrical contact part made of a sintered copper-graphite composite material containing between 90 and 98% copper or copper alloy by weight,
said graphite being in the form of flakes, said flakes being oriented with respect to said axis of symmetry such that the main axis P of more than 50% of said graphite flakes is inclined at less than 45° - with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
/rho ⊥
being greater than 1.2 and the ratio R of bending strength R ∥
/R ⊥
being less than 0.8, where ∥
designates the direction parallel to said axis of symmetry and ⊥
the perpendicular direction,said composite having a specific gravity of between 6.5 and 8.5 comprising; preparing a mixture of graphite powder, copper or copper-alloy powder and at least one solid lubricant, forming a raw casting by cold axial compression of the mixture in a mold, in such a way that the axis of compression coincides with the axis of symmetry of the aforesaid part, sintering the raw casting under a reducing atmosphere. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
- with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
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17. An assembly of rotating contact parts comprising a support part made of an insulating material and rotating contact parts wherein said rotating contact parts are made of a sintered copper-graphite composite material containing between 90 and 98% copper or copper alloy by weight,
said graphite being in the form of flakes, said flakes being oriented with respect to said axis of symmetry such that the main axis P of more than 50% of said graphite flakes is inclined at less than 45° - with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
/rho ⊥
being greater than 1.2 and the ratio R of bending strength R ∥
/R ⊥
being less than 0.8, where ∥
designates the direction parallel to said axis of symmetry and ⊥
the perpendicular direction,said composite having a specific gravity of between 6.5 and 8.5. - View Dependent Claims (18, 19, 20, 21)
- with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
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22. Electrical machine, comprising at least one rotating electrical contact part wherein said at least one part is made of a sintered copper-graphite composite material containing between 90 and 98% copper or copper alloy by weight,
said graphite being in the form of flakes, said flakes being oriented with respect to said axis of symmetry such that the main axis P of more than 50% of said graphite flakes is inclined at less than 45° - with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
/rho ⊥
being greater than 1.2 and the ratio R of bending strength R ∥
/R ⊥
being less than 0.8, where ∥
designates the direction parallel to said axis of symmetry and ⊥
the perpendicular direction,said composite having a specific gravity of between 6.5 and 8.5.
- with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
-
23. An electrical contact part made of a sintered copper-graphite composite material containing between 90 and 98% copper or copper alloy by weight,
said graphite being in the form of flakes, said flakes being oriented with respect to said axis of symmetry such that the main axis P of more than 50% of said graphite flakes is inclined at less than 45° - with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
/rho ⊥
being greater than 1.2 and the ratio R of bending strength R ∥
/R ⊥
being less than 0.8, where ∥
designates the direction parallel to said axis of symmetry and ⊥
the perpendicular direction,said composite having a specific gravity of between 6.5 and 8.5. - View Dependent Claims (24, 25)
- with respect to said axis of symmetry, the ratio Rho of resistivity rho ∥
Specification