Threaded nut of a ball screw and method for producing same

Patent metadata

Field	Value
Publication number	US-12372142-B2
Application number	US-202118265791-A
Country	US
Kind code	B2
Filing date	Nov 3, 2021
Priority date	Dec 9, 2020
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

The disclosure relates to a threaded nut of a ball screw, the threaded nut having an inner sleeve made of sheet metal and an outer sleeve made of sheet metal, which are nested axially in one another to form a nut sleeve. The nut sleeve is provided with a thread, which is formed helically about a longitudinal axis of the threaded nut and which forms, on the inner circumference of the nut sleeve, a ball groove wound helically about the longitudinal axis of the threaded nut and, and on the outer circumference of the nut sleeve, a helically wound outer ridge.

First claim

The invention claimed is:

1. A threaded nut of a ball screw, the threaded nut comprising:
an inner sleeve constructed of sheet metal, and
an outer sleeve constructed of sheet metal, the inner sleeve and the outer sleeve separately nested axially in one another to form a nut sleeve having a thread, the thread formed helically about a longitudinal axis of the threaded nut and forming: i) on an inner circumference of the nut sleeve, a ball groove wound helically about the longitudinal axis of the threaded nut and, ii) on an outer circumference of the nut sleeve, a helically wound outer ridge, such that the inner sleeve is threadedly engaged with the outer sleeve via the forming of the ball groove and the helically wound outer ridge so as to axially join the separately nested inner sleeve and the outer sleeve.

2. The threaded nut according to claim 1 , wherein the nut sleeve forms an inner ridge wound helically about the longitudinal axis on the outer circumference of the inner sleeve, and the outer sleeve forms a helically wound groove configured to be engaged by the inner ridge of the inner sleeve.

3. The threaded nut according to claim 1 , wherein at least one outer hole is formed along the thread on the outer sleeve, and a material of the inner sleeve is formed in the at least one outer hole.

4. The threaded nut according to claim 1 , wherein the nut sleeve includes at least one through-hole configured for a return or deflection of balls along the thread, the at least one through-hole formed by an inner hole of the inner sleeve and by an outer hole of the outer sleeve.

5. The threaded nut according to claim 4 , wherein the inner sleeve includes a formed edge section at an edge of the inner hole, the formed edge section forming a ball inlet ramp.

6. The threaded nut according to claim 5 , wherein the through-hole is formed by a larger outer hole arranged on the outer sleeve and a smaller inner hole arranged on the inner sleeve.

7. The threaded nut according to claim 1 , wherein the nut sleeve includes a connecting component on at least one axial end.

8. The threaded nut according to claim 7 , wherein the inner sleeve and the outer sleeve include sleeve parts arranged to be axially adjacent, and one of the sleeve parts is also part of the connecting component.

9. The threaded nut according to claim 1 , wherein the inner sleeve is constructed of sheet steel with a carbon content greater than 0.3% and the outer sleeve is constructed of sheet steel with a carbon content of less than 0.3%.

10. A method for producing the threaded nut according to claim 1 , the method comprising:
nesting an inner sleeve constructed of sheet metal and an outer sleeve constructed of sheet metal axially in one another to form a nut sleeve,
inserting the nut sleeve into a die so that a groove on an inner circumference of the die extends helically about the longitudinal axis of the threaded nut,
moving a forming tool into the nut sleeve to form: i) a thread in the nut sleeve, the thread wound helically about a longitudinal axis and forming a helically wound ball groove on the inner circumference of the nut sleeve, and ii) a helically wound outer ridge extending along the thread on the outer circumference of the nut sleeve, the outer ridge formed via the groove on the inner circumference of the die.

11. The method for producing the threaded nut according to claim 10 , wherein the outer sleeve includes at least one outer hole arranged along the thread before nesting with the inner sleeve to form the nut sleeve, and the forming tool forms material of the inner sleeve into the at least one outer hole to form a formed edge section in a region of an edge of the at least one outer hole.

12. A method for producing the threaded nut according to claim 9 , the method comprising:
hardening the nut sleeve in a heat treatment process after forming the ball groove and the outer ridge so that the inner sleeve has a martensitic or a bainitic structure with a higher proportion of martensite or bainite than the outer sleeve.

13. A threaded nut of a ball screw, the threaded nut comprising:
a longitudinal axis,
an outer sleeve constructed of sheet steel, the outer sleeve having:
an outer circumference formed with an outer ridge extending helically about the longitudinal axis, and
an inner circumference formed with a groove extending helically about the longitudinal axis,

an inner sleeve constructed of sheet steel and separately disposed within the outer sleeve to form a nut sleeve, the inner sleeve having:
an inner circumference formed with a ball groove extending helically about the longitudinal axis, and
an outer circumference formed with an inner ridge extending helically about the longitudinal axis, the inner ridge threadedly engaging the groove formed on the inner circumference of the outer sleeve so as to axially join the separately disposed inner sleeve within the outer sleeve.

14. The threaded nut according to claim 13 , wherein one of the outer sleeve or the inner sleeve further comprises an integrally formed first radial flange arranged at a first axial end of the nut sleeve.

15. The threaded nut according to claim 14 , wherein a remaining one of the outer sleeve or the inner sleeve further comprises an integrally formed second radial flange arranged at a second axial end of the nut sleeve.

16. The threaded nut according to claim 14 , wherein the first radial flange is formed with a ball groove configured for a ball bearing.

17. The threaded nut according to claim 16 , wherein a remaining one of the outer sleeve or the inner sleeve further comprises an integrally formed second radial flange arranged at the first axial end, and the second radial flange is configured to support the first radial flange.

18. The threaded nut according to claim 13 , wherein the nut sleeve further comprises a plurality of through-holes arranged on the circumference of the nut sleeve, the plurality of through-holes extending through the inner sleeve and the outer sleeve.

19. The threaded nut according to claim 18 , wherein inner sleeve further comprises a first through-hole and the outer sleeve further comprises a second through-hole aligned with the first through-hole, and a portion of the second through-hole extends radially into the first through-hole.

20. A method for producing a threaded nut, the method comprising:
providing an outer sleeve constructed of sheet metal,
providing an inner sleeve constructed of sheet metal,
inserting the inner sleeve within the outer sleeve to form a nut sleeve,
inserting the nut sleeve into a die,
moving a forming tool into the nut sleeve so as to simultaneously form: i) a helically wound ball groove on an inner circumference of the inner sleeve, ii) a helically wound inner ridge on an outer circumference of the inner sleeve, iii) a helically wound groove on an inner circumference of the outer sleeve, the helically wound groove engaged with the helically wound inner ridge, and iv) a helically wound outer ridge on an outer circumference of the outer sleeve, the outer ridge formed via grooves arranged on the die.

Assignees

• Schaeffler Technologies Ag

Inventors

• Kreutzer Mario
• Baier Richard
• Pfeffer Claus
• Kandler Thomas

Classifications

• F16H2025/249

  Materials or coatings for screws or nuts · CPC title

• F16H2025/2481

  Special features for facilitating the manufacturing of spindles, nuts, or sleeves of screw devices · CPC title

• F16H25/2214

  with elements for guiding the circulating balls · CPC title

• B21D53/24

  nuts or like thread-engaging members · CPC title

• B21H3/08

  internal screw-threads · CPC title