Composite rotor and output shaft for galvanometer motor and method of manufacture thereof
View Patent ↗A rotor is disclosed for a galvanometer system. A rotor includes a permanent magnet core, a sleeve and at least one shaft unit. The sleeve encloses and attaches to at least a portion of the permanent magnet core. The sleeve is formed of a material having a density of less than about 0.283 lb/in 3 . The shaft unit is attached to both the permanent magnet core and to the sleeve. An output device may be coupled to the shaft unit, and the shaft unit is formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
1. A rotor for a galvanometer system, said rotor comprising:
a permanent magnet core;
a sleeve enclosing and attached to at least a portion of said permanent magnet core, said sleeve being formed of a material having a density of less than about 0.283 lb/in 3 ; and
at least one shaft unit that is bonded to both said permanent magnet core and to said sleeve by a solder that includes tin, silver and copper, and to which an output device may be coupled.
2. The rotor as claimed in claim 1 , wherein said rotor further includes a coupling unit attached to said shaft unit such that the output device may be coupled to said shaft unit via said coupling unit, said coupling unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
3. The rotor as claimed in claim 2 , wherein said shaft unit and said coupling unit are formed of different materials.
4. The rotor as claimed in claim 1 , wherein said shaft unit is formed of a material that includes titanium.
5. The rotor as claimed in claim 4 , wherein said sleeve is nickel plated on an inner surface thereof.
6. The rotor as claimed in claim 1 , wherein said permanent magnet core, said sleeve and said shaft unit are joined to one another by solder.
7. The rotor as claimed in claim 6 , wherein said solder has a thickness of less than about 0.0005 inches.
8. The rotor as claimed in claim 6 , wherein said solder includes tin, silver and copper.
9. The rotor as claimed in claim 8 , wherein said solder includes about 92% to about 96% tin, about 3% to about 7% silver, and about 0.1% to about 3% copper.
10. The rotor as claimed in claim 6 , where said solder includes no lead.
11. The rotor as claimed in claim 1 , wherein said permanent magnet core is formed of a material that has a first coefficient of thermal expansion and the sleeve is formed of a material that has a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion.
12. The rotor as claimed in claim 1 , wherein said permanent magnet core and said sleeve are joined together by a bonding layer that is in compression at temperatures above room temperature.
13. The rotor as claimed in claim 1 , wherein said shaft unit is formed of a material that includes beryllium.
14. The rotor as claimed in claim 1 , wherein a first portion of said rotor that is adjacent one or more rotor bearings is formed of a material having an inertia that is less than an inertia of a second portion of said rotor that includes said permanent magnet.
15. The rotor as claimed in claim 14 , wherein said first portion of said rotor has a diameter that is less than said second portion of said rotor.
16. The rotor as claimed in claim 1 , wherein said rotor is employed in a galvanometer.
17. The rotor as claimed in claim 16 , wherein said galvanometer is employed in a laser marking system.
18. A rotor for a galvanometer system, said rotor comprising:
a permanent magnet core;
a sleeve enclosing and attached to at least a portion of said permanent magnet core, said sleeve being formed of a material having a density of less than about 0.283 lb/in 3 ; and
at least one shaft unit that is attached to both said permanent magnet core and to said sleeve by a solder that includes tin, silver and copper, and to which an output device may be coupled, said shaft unit being formed of a material having a modulus of elasticity of at least about 31×10 6 psi.
19. The rotor as claimed in claim 18 , wherein said rotor further includes a coupling unit attached to said shaft unit such that the output device may be coupled to said shaft unit via said coupling unit, said coupling unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
20. The rotor as claimed in claim 19 , wherein said shaft unit and said coupling unit are formed of different materials.
21. The rotor as claimed in claim 18 , wherein said shaft unit is formed of a material that includes titanium.
22. The rotor as claimed in claim 21 , wherein said sleeve is nickel plated on an inner surface thereof.
23. The rotor as claimed in claim 18 , wherein said permanent magnet core, said sleeve and said shaft unit are joined to one another by solder.
24. The rotor as claimed in claim 18 , wherein said solder has a thickness of less than about 0.0005 inches.
25. The rotor as claimed in claim 18 , wherein said permanent magnet core is formed of a material that has a first coefficient of thermal expansion and the sleeve is formed of a material that has a second coefficient of thermal expansion that is less than the first coefficient of thermal expansion.
26. The rotor as claimed in claim 18 , wherein said permanent magnet core and said sleeve are joined together by a bonding layer that is in compression at temperatures above room temperature.
27. The rotor as claimed in claim 18 , wherein said shaft unit is formed of a material that includes beryllium.
28. The rotor as claimed in claim 18 , wherein a first portion of said rotor that is adjacent one or more rotor bearings is formed of a material having an inertia that is less than an inertia of a second portion of said rotor that includes said permanent magnet.
29. The rotor as claimed in claim 28 , wherein said first portion of said rotor has a diameter that is less than said second portion of said rotor.
30. The rotor as claimed in claim 18 , wherein said rotor is employed in a galvanometer.
31. The rotor as claimed in claim 30 , wherein said galvanometer is employed in a laser marking system.
32. A rotor for a galvanometer system, said rotor comprising:
a permanent magnet core;
a sleeve enclosing and attached to at least a portion of said permanent magnet core, said sleeve being formed of a material having a density of less than about 0.283 lb/in 3 ; and
at least one shaft unit that is bonded to both said permanent magnet core and to said sleeve by a solder that includes tin, silver and copper, and to which an output device may be coupled, said shaft unit being formed of a material having a damping of less than about 1/(31×10 6 )in 2 /lb.
33. The rotor as claimed in claim 32 , wherein said rotor further includes a coupling unit attached to said shaft unit such that the output device may be coupled to said shaft unit via said coupling unit, said coupling unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
34. A rotor for a galvanometer system, said rotor comprising:
a permanent magnet core;
a sleeve enclosing and attached to at least a portion of said permanent magnet core, said sleeve being formed of a material having a density of less than about 0.283 lb/in 3 ;
at least one shaft unit that is attached to both said permanent magnet core and to said sleeve, and to which an output device may be coupled, said shaft unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug; and
a coupling unit attached to said shaft unit such that the output device may be coupled to said shaft unit via said coupling unit, said coupling unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
35. The rotor as claimed in claim 34 , wherein said shaft unit and said coupling unit are formed of different materials.
36. The rotor as claimed in claim 34 , wherein said shaft unit is formed of a material that includes titanium.
37. The rotor as claimed in claim 34 , wherein said permanent magnet core, said sleeve and said shaft unit are joined to one another by solder.
38. The rotor as claimed in claim 34 , wherein said shaft unit is formed of a material that includes beryllium.
39. The rotor as claimed in claim 34 , wherein said galvanometer is employed in a laser marking system.
40. A rotor for a galvanometer system, said rotor comprising:
a permanent magnet core;
a sleeve enclosing and attached to at least a portion of said permanent magnet core, said sleeve being formed of a material having a density of less than about 0.283 lb/in 3 ; and
at least one shaft unit that is attached to both said permanent magnet core and to said sleeve by a solder that includes tin, silver and copper, and to which an output device may be coupled, said shaft unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
41. The rotor as claimed in claim 40 , wherein said rotor further includes a coupling unit attached to said shaft unit such that the output device may be coupled to said shaft unit via said coupling unit, said coupling unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
42. The rotor as claimed in claim 41 , wherein said shaft unit and said coupling unit are formed of different materials.
43. The rotor as claimed in claim 40 , wherein said shaft unit is formed of a material that includes titanium.
44. The rotor as claimed in claim 40 , wherein said shaft unit is formed of a material that includes beryllium.
45. A rotor for a galvanometer system, said rotor comprising:
a permanent magnet core;
a sleeve enclosing and attached to at least a portion of said permanent magnet core, said sleeve being formed of a material having a density of less than about 0.283 lb/in 3 ;
at least one shaft unit that is attached to both said permanent magnet core and to said sleeve, and to which an output device may be coupled, said shaft unit being formed of a material having a modulus of elasticity of at least about 31×10 6 psi; and
a coupling unit attached to said shaft unit such that the output device may be coupled to said shaft unit via said coupling unit, said coupling unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
46. The rotor as claimed in claim 45 , wherein said shaft unit and said coupling unit are formed of different materials.
47. The rotor as claimed in claim 45 , wherein said shaft unit is formed of a material that includes beryllium.
48. A rotor for a galvanometer system, said rotor comprising:
a permanent magnet core;
a sleeve enclosing and attached to at least a portion of said permanent magnet core, said sleeve being formed of a material having a density of less than about 0.283 lb/in 3 ; and
at least one shaft unit that is attached to both said permanent magnet core and to said sleeve by a solder that includes tin, silver and copper that is introduced through a tap hole in said sleeve, and to which an output device may be coupled, said shaft unit being formed of a material having a modulus of elasticity of at least about 31×10 6 psi.
49. The rotor as claimed in claim 48 , wherein said rotor further includes a coupling unit attached to said shaft unit such that the output device may be coupled to said shaft unit via said coupling unit, said coupling unit being formed of a material having a dynamic stiffness of at least about 1.00×10 9 lb in 7 /slug.
50. The rotor as claimed in claim 49 , wherein said shaft unit and said coupling unit are formed of different materials.