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DE-112021008306-B4 - Shaft coupling and shaft for the shaft coupling

DE112021008306B4DE 112021008306 B4DE112021008306 B4DE 112021008306B4DE-112021008306-B4

Abstract

Shaft coupling (1) for switching a first shaft (2) with a second shaft (3) arranged coaxially thereto, at least comprising the first shaft (2) which has on a circumferential surface (4) a plurality of first ball tracks (8) extending along an axis of rotation (5) over at least a first section (6) and a second section (7), which are spaced apart from each other along a circumferential direction (9) in the first section (6) by first webs (10) and in the second section (7) by second webs (11), as well as a plurality of first balls (12) arranged in the first section (6) and a plurality of second balls (13) arranged in the second section (7); wherein the first ball tracks (8) in the first section (6) are connected to each other via first openings (14) arranged in alignment along the circumferential direction (9) and in the second section (7) via second openings (15) arranged in alignment along the circumferential direction (9); wherein the shaft coupling (1) is switchable between at least two positions and the balls (12, 13) are displaceable between the positions within the respective section (6, 7) along the ball tracks (8); wherein the balls (12, 13) are arranged in the circumferential direction (9) in a coupled position aligned with the webs (10, 11) and in a decoupled position aligned with the openings (14, 15); wherein in the first section (6) a first end face (16) of the first webs (10) pointing towards the first openings (14) is smaller than in the second section (7) a second end face (17) pointing towards the second openings (15).

Inventors

  • Jan Haupt
  • Moritz Abbenhaus
  • Thomas Weckerling
  • Maximilian Werkhausen

Assignees

  • GKN AUTOMOTIVE LTD.

Dates

Publication Date
20260513
Application Date
20211001

Claims (11)

  1. Shaft coupling (1) for switching a first shaft (2) with a second shaft (3) arranged coaxially thereto, at least comprising the first shaft (2) which has on a circumferential surface (4) a plurality of first ball tracks (8) extending along an axis of rotation (5) over at least a first section (6) and a second section (7), which are spaced apart from each other along a circumferential direction (9) in the first section (6) by first webs (10) and in the second section (7) by second webs (11), as well as a plurality of first balls (12) arranged in the first section (6) and a plurality of second balls (13) arranged in the second section (7); wherein the first ball tracks (8) in the first section (6) are connected to each other via first openings (14) arranged in alignment along the circumferential direction (9) and in the second section (7) via second openings (15) arranged in alignment along the circumferential direction (9); wherein the shaft coupling (1) at least between two positions can be switched and the balls (12, 13) can be displaced between the positions within the respective section (6, 7) along the ball tracks (8); wherein the balls (12, 13) are arranged in the circumferential direction (9) in a coupled position aligned with the webs (10, 11) and in a decoupled position aligned with the openings (14, 15); wherein in the first section (6) a first end face (16) of the first webs (10) pointing towards the first openings (14) is smaller than in the second section (7) a second end face (17) pointing towards the second openings (15).
  2. Shaft coupling (1) according Patent claim 1 , wherein a chamfer (18) adjoins the first end face (16) at least towards one of the first ball tracks (8) arranged adjacent to the first bridge (10), through which a first entry opening (19) of the first ball track (8) is formed which is enlarged in the circumferential direction (9); wherein the chamfer (18) causes a width (20) of the first ball track (8) to taper progressively from the first entry opening (19) and along the axis of rotation (5).
  3. Shaft coupling (1) according to one of the preceding claims, wherein a chamfer (18) adjoins the first end face (16) towards both of the first ball tracks (8) arranged adjacent to the first web (10), through which a first entry opening (19) of the first ball tracks (8) is formed which is enlarged in the circumferential direction (9); wherein the chamfers (18) cause a width (20) of the first ball tracks (8) to taper progressively from the first entry opening (19) and along the axis of rotation (5).
  4. Shaft coupling (1) according to one of the preceding claims, wherein the first end face (16) is at most 95% of the second end face (17).
  5. Shaft coupling (1) according to one of the preceding claims, wherein the first balls (12) are arranged in the decoupled position along the axis of rotation (5) at a first distance (21) to the first end faces (16) and the second balls (13) at a second distance (22) to the second end faces (17), wherein the first distance (21) is less than the second distance (22).
  6. Shaft coupling (1) according to one of the preceding claims, at least comprising the second shaft (3) with a plurality of second ball tracks (23) extending along the axis of rotation (5) and a sleeve (24) at least partially covering the first ball tracks (8) and the second ball tracks (23) along the axis of rotation (5) with third ball tracks (25) and third balls (26); wherein the first and second balls (12, 13) are arranged in first track pairs (27) formed by the first ball tracks (8) with the third ball tracks (25) and the third balls (26) are arranged in second track pairs (28) formed by the second ball tracks (23) with the third ball tracks (25); wherein by a displacement (29) of the sleeve (24) along the axis of rotation (5) the balls (12, 13, 26) can be displaced between the positions along the ball tracks (8, 23, 25), so that in the coupled position the shafts (2, 3) are connected to each other in a rotationally fixed manner and in the decoupled position can be rotated against each other.
  7. Shaft coupling (1) according Patent claim 6 , wherein the shafts (2, 3) are arranged side by side along the axis of rotation (5) and the sleeve (24) extends in a radial direction (30) outside over the first ball tracks (8) and the second ball tracks (23), wherein the third ball tracks (25) form outer ball tracks and together with the inner first ball tracks (8) form the first track pairs (27) and together with the inner second ball tracks (23) form the second track pairs (28).
  8. Shaft coupling (1) according Patent claim 6 , wherein first ball tracks (8) and second ball tracks (23) overlap each other along the axis of rotation (5) and the sleeve (24) is arranged along a radial direction (30) between the first ball tracks (8) and the second ball tracks (23), wherein one shaft (2, 3) has inner ball tracks and the other shaft (3, 2) has outer ball tracks, and the sleeve (24) has inner third ball tracks (25) and outer third ball tracks (25).
  9. Shaft coupling (1) according to one of the preceding claims, wherein the first shaft (2) has a plurality of second sections (7) which are arranged adjoining one another along the axis of rotation (5).
  10. Shaft coupling (1) according to one of the preceding claims, wherein a cage (31) is arranged between the sleeve (24) and each shaft (2, 3), wherein the balls (12, 13, 26) are arranged at fixed distances (33) to each other via the cage (31) at least relative to an axial direction (32) extending along the axis of rotation (5).
  11. Shaft for a shaft coupling according to one of the preceding claims, wherein the shaft has on a circumferential surface (4) a plurality of first ball tracks extending along an axis of rotation (5) over at least a first section (6) and a second section (7). (8) has, which are spaced apart from one another along a circumferential direction (9) in the first section (6) by first webs (10) and in the second section (7) by second webs (11); wherein the first ball tracks (8) in the first section (6) are connected to each other along the circumferential direction (9) by first openings (14) aligned with each other and in the second section (7) by second openings (15) aligned with each other along the circumferential direction (9); wherein in the first section (6) a first end face (16) of the first webs (10) pointing towards the first openings (14) is smaller than in the second section (7) a second end face (17) pointing towards the second openings (15).

Description

The invention relates to a shaft coupling for the switchable connection of a first shaft to a second shaft, which are arranged coaxially and have a common axis of rotation. The invention further relates to a shaft of the shaft coupling. The shafts can be connected to each other in a rotationally fixed manner (i.e., not rotatable relative to each other) via the shaft coupling for the transmission of torques (coupled position) or separated from each other (decoupled position). In the decoupled position, the shafts can rotate independently of each other, without any transmission of torques. From the DE 10 2019 129 818 A1 A shaft coupling for the switchable connection of a first shaft to a second shaft is known. The shafts have ball tracks which, together with ball tracks of a sleeve, form pairs of tracks. The balls are displaced by moving the sleeve along the axis of rotation. One of the shafts has openings between the ball tracks into which the balls can be moved. If the balls are arranged in the area of the openings, the shafts can rotate independently of each other. If the balls are arranged outside the openings, i.e., between the webs of the ball tracks, the shafts are coupled to each other. In such shaft couplings, the individual ball tracks of a shaft are arranged at angular intervals along the circumference. These angular distances must be bridged to switch from the decoupled to the coupled position, i.e., to move the balls into the ball tracks or into the area between the webs. The relatively large angular distance necessitates a long switching time to establish the coupled position. Furthermore, switching is only possible within a very small angular range, determined by the (excessive) size of the ball track entrance opening relative to the balls. This also severely restricts the permissible difference in rotational speeds of the shafts to be coupled. Increasing the size of the inlet opening or the width of the ball track is not possible, as this would worsen the NVH (noise, vibration, and harshness) performance of the shaft coupling (greater play of the balls in the ball tracks relative to the circumference). Reducing the angular spacing, for example by increasing the number of ball tracks, leads to a decrease in the transmissible torque. A smaller angular spacing on a larger effective diameter (ball tracks arranged on a larger diameter shaft) results in a larger installation space requirement, which is often not available. From the DE 37 01 898 A1 A clutch with a shift sleeve is known. From the WO 2006/018096 A1 A longitudinal displacement unit designed to connect two shafts is known. From the DE 10 2010 051 949 A1 A device for creating and releasing a rotationally fixed connection between two shafts is known. From the DE 10 2016 110 389 A1 A vibration decoupling arrangement is known which allows two shafts to be connected. The US 2018/0180144 A1 is directed towards an actuator that controls the transmission of force between a cylinder and a shaft. The object of the present invention is to at least partially solve the problems mentioned with reference to the prior art. In particular, a shaft coupling is to be proposed that can transmit high torques in a compact design. Specifically, short actuation strokes and low switching forces are to be achieved. Furthermore, switching of the shaft coupling should be possible even with significant differences in the rotational speeds of the shafts. To solve these problems, a shaft coupling with the features according to claim 1 and a shaft with the features according to claim 11 contribute. Advantageous further developments are the subject of the dependent claims. The features listed individually in the claims can be combined with one another in a technologically meaningful way and can be supplemented by explanatory details from the description and/or details from the figures, thereby showing further embodiments of the invention. A shaft coupling is proposed for the switchable connection of a first shaft to a second shaft. The shafts are arranged coaxially and have a common axis of rotation. The shaft coupling comprises at least the first shaft and a plurality of first balls and second balls. The first shaft has, on a circumferential surface, a plurality of first ball tracks extending along an axis of rotation over at least a first section and a second section. The first ball tracks are The first balls are spaced apart along a circumferential direction by first webs in the first section and by second webs in the second section. The majority of the first balls are located in the first section (in every position of the shaft coupling). The majority of the second balls are located in the second section (in every position of the shaft coupling). The first ball tracks are connected in the first section by first openings aligned with each other along the circumferential direction, and in the second section by second openings aligned with each other along the circumfer