Shaft for an open-end spinning rotor and method of making same

• US 5,901,545 A
• Filed: 11/07/1997
• Issued: 05/11/1999
• Est. Priority Date: 11/09/1995
• Status: Expired due to Fees

• Current Assignee: Maschinenfabrik Rieter AG (Rieter Holding AG)
• Original Assignee: Fritz Stahlecker, Hans Stahlecker
• Inventors: Stahlecker, Fritz
• Primary Examiner(s): Stryjewski, William
• Application Number:
  US08/966,359
• Time in Patent Office: 550 Days
• Field of Search: 57/406, 57/414, 57/415, 57/416, 57/417, 57/404, 384/610, 384/244, 384/245
• US Class Current: 57/406
• CPC Class Codes: D01H 4/12 Rotor bearings; Arrangements for driving or stopping control therefor D01H4/42
• CPC Class Codes: F16C 17/08 for supporting the end face of a shaft or other member, e.g. footstep bearings
• CPC Class Codes: F16C 2340/18 Apparatus for spinning or twisting in general D01H

Abstract

In the case of a shaft for an open-end spinning rotor a supporting element is fixed in a concentric recess of the shaft. The supporting element is disposed with a radially extending supporting surface against a vibrating ball of a step bearing. A ball is used as a supporting element, a section of which ball projects out of the recess. The projecting section is radially flattened in relation to the shaft and thus forms the radially extending supporting surface. Because of its ball shape, the supporting element can be easily placed in the recess. In the case of a misaligned arrangement of the vibrating ball, the radial flattening prevents the axial position of the open-end spinning rotor from being displaced and undesirable radial forces being exerted on the shaft.

Claims

1. A method of making a shaft assembly for an open-end spinning rotor, comprising:

providing a spinning rotor shaft having a free end with a recess therein,

placing a support ball into the recess,

fixing said support ball to the shaft,

and forming a plane supporting surface on the support ball for contacting a vibrating supporting ball of a step bearing when in an in use position on a rotor spinning machine.

2. A method according to claim 1, wherein said fixing includes press fitting said support ball into said recess.

3. A method according to claim 2, wherein said forming said plane supporting surface includes grinding said support ball after said press fitting.

4. A method according to claim 1, wherein said forming said plane supporting surface includes machining said support ball after placing of said support ball into the recess and fixing of said support ball to the shaft.

5. A method according to claim 1, wherein said plane surface extends radially with respect to an axis of said rotor shaft.

6. A method according to claim 5, comprising forming said plane surface by machining after placing said support ball into the recess.

7. A method according to claim 6, wherein said machining includes grinding the plane surface.

8. A method according to claim 1, wherein the recess comprises a stopping face for axially fixing the support ball.

9. A method according to claim 8, wherein the recess comprises a hollow conical section, whose circumferential surface forms the stopping face.

10. A method according to claim 9, wherein the support ball is held in the recess by a press fit.

11. A method according to claim 10, wherein the shaft is hardened at least in the area adjacent to the recess.

12. An open end spinning rotor support assembly comprising:

a rotor shaft with one axial end fixably connected to a spinning rotor and an opposite axial end having a recess,

a support ball formed separately of said rotor shaft and disposed in said recess and projecting axially out of said recess to form a radially extending supporting surface,

and a vibrating supporting ball of a step bearing engaging said supporting surface of the support ball.

13. An open end spinning rotor support assembly according to claim 12, wherein the supporting surface is made by removing material from the support ball.

14. An open end spinning rotor support assembly according to claim 13, wherein the support ball is made of a harder material than the material of at least one of the vibrating ball and the rotor shaft.

15. An open end spinning rotor support assembly according to claim 14, wherein the recess comprises a stopping face for axially fixing the support ball.

16. An open end spinning rotor support assembly according to claim 15, wherein the recess comprises a hollow conical section, whose circumferential surface forms the stopping face.

17. An open end spinning rotor support assembly according to claim 16, wherein the support ball is held in the recess by a press fit.

18. An open end spinning rotor support assembly according to claim 17, wherein the shaft is hardened at least in the area adjacent to the recess.

19. A method of making a rotor shaft for an open end spinning rotor having a first end which in use supports a spinning rotor and an opposite second end, said method comprising:

providing a cylindrical shaft, hardening the cylindrical shaft at a second end region thereof,

drilling an axially aligned bore into the second end of the shaft,

subsequently inserting a substantially ball shaped ceramic supporting element in the bore drilled in the shaft and fixing the supporting element in said bore to the shaft, and

subsequently machining a substantially plane supporting surface extending radially of the shaft on said ball shaped supporting element at the side thereof facing away from the shaft and spaced a small distance from the axial second end of the shaft.

20. A method of making a rotor shaft for an open end spinning rotor according to claim 19, wherein said machining includes grinding the supporting surface on the ball shaped ceramic element.

21. A method according to claim 19, wherein said drilling an axially aligned bore includes drilling a stepped bore with a first cylindrical end section open to the second end of the shaft, a second cylindrical section, and a conical section connecting the first and second cylindrical sections, said drilling being performed by a single drill bit forming the sections, and

wherein said ball shaped ceramic element is press fit into said first cylindrical section to a position axially supported at the conical section, with the second cylindrical section forming a free open space adjacent a center section of the ball shaped element.

22. A shaft for an open-end spinning rotor having a free end provided with a supporting element for a vibrating supporting ball of a step bearing, said supporting element having the form of a support ball which is pressed into the free end of the shaft and which has a plane supporting surface which is engageable in use with the vibrating supporting ball.

23. A shaft according to claim 22, wherein the supporting surface is made by removing material from the support ball.

24. A shaft according to claim 23, wherein the support ball is made of a ceramic material.

25. A shaft according to claim 24, wherein the recess comprises a stopping face for axially fixing the support ball.

26. A shaft according to claim 25, wherein the recess comprises a hollow conical section, whose circumferential surface forms the stopping face.

27. A shaft according to claim 25, wherein the support ball is held in the recess by a press fit.

28. A shaft according to claim 25, wherein the shaft is hardened at least in the area adjacent to the recess.

29. A shaft according to claim 24, wherein the support ball is held in the recess by a press fit.

30. A shaft according to claim 24, wherein the shaft is hardened at least in the area adjacent to the recess.

31. A shaft according to claim 30, wherein the removal of material takes place by means of grinding the supporting surface of the support ball which has been pressed into place.

32. A shaft according to claim 22, wherein the support ball is made of a ceramic material.

33. A shaft according to claim 22, wherein the recess comprises a stopping face for axially fixing the support ball.

34. A shaft according to claim 33, wherein the recess comprises a hollow conical section, whose circumferential surface forms the stopping face.

35. A shaft according to claim 34, wherein the support ball is held in the recess by a press fit.

36. A shaft according to claim 34, wherein the shaft is hardened at least in the area adjacent to the recess.

37. A shaft according to claim 22, wherein the support ball is held in the recess by a press fit.

38. A shaft according to claim 37, wherein the shaft is hardened at least in the area adjacent to the recess.

39. A shaft according to claim 22, wherein the shaft is hardened at least in the area adjacent to the recess.

40. A shaft for an open-end spinning rotor having a first end designed to be connected to said spinning rotor and a second end designed to be supported by a step bearing,

wherein the second end of the shaft has a recess, and

wherein a support ball formed separately of said rotor shaft is disposed and fixed in said recess, said support ball having a surface extending radially of the rotor shaft for engaging with a vibrating supporting ball of said step bearing.

41. A shaft for an open-end spinning rotor according to claim 40, wherein said support ball is supported in the shaft so as to rest against a conical contact surface adjoining a cylindrical bore at the second end of the shaft.

42. A shaft for an open-end spinning-rotor according to claim 41, wherein the supporting surface is formed following insertion of the ball shaped supporting element in the shaft by grinding away material of the support ball.

43. A shaft for an open-end spinning rotor according to claim 40, wherein the supporting surface is disposed maximally less than 1 mm from the axial end of the shaft.

44. A shaft for an open-end spinning rotor according to claim 40, wherein the recess includes:

a stepped bore with a first cylindrical section having a diameter substantially equal to the diameter of the support ball,

a second cylindrical section, and

a conical section joining said first and second cylindrical section,

said first cylindrical section engaging the support ball when in an in use position, while said second cylindrical section forms a free space behind a central portion of said support ball and said conical section forms an axial stop surface for the support ball.

45. A shaft for an open-end spinning rotor according to claim 44, wherein said second cylindrical section has a diameter approximately half the diameter of the first cylindrical section, and the conical section extends at an angle of between 35°

and 45°

through a central axis of the shaft and bore.

46. A shaft for an open-end spinning rotor according to claim 45, wherein said angle is approximately 40°

.

47. A shaft for an open-end spinning rotor according to claim 46, wherein said second cylindrical section has an axial end in the shape of a cone formed by a drill forming the bore.

48. A shaft for an open-end spinning rotor according to claim 44, wherein the second cylindrical section is longer than the radius of the ball shaped element.

49. A shaft according to claim 40, wherein said supporting surface is made by removing material from the support ball after the support ball has been disposed and fixed in the recess of the rotor shaft.

50. A shaft according to claim 40, wherein said support ball is formed of ceramic material.

51. An open end spinning rotor shaft assembly comprising:

a rotor shaft with one axial end fixably connectable to a spinning rotor and an opposite axial end having a recess, and

a support ball formed separately of said rotor shaft and disposed in and fixed in said recess, said support ball having a radially extending supporting surface adapted to engage a vibrating supporting ball of a step bearing when in an in use position on a rotor spinning machine.