DEVICE FOR POSITIONING AT LEAST ONE SHAFT

Abstract

A device for positioning a shaft relative to a functional element including at least one hub for the shaft. The device may include a tailstock for axially aligning the shaft with respect to the at least one hub of the functional element. The tailstock may include a radially adjustable centring cone for the shaft. The tailstock may have an outer diameter that is smaller than an inner diameter of the at least one hub.

Claims

1. A device for positioning a shaft relative to a functional element including at least one hub for the shaft, the device comprising: a tailstock for axially aligning the shaft with respect to the at least one hub of the functional element; the tailstock including a radially adjustable centring cone for the shaft; and wherein the tailstock has an outer diameter that is smaller than an inner diameter of the at least one hub.

2. The device according to claim 1, wherein the centring cone is adjustably mounted on the tailstock via at least one of an air cushion and a ball bearing such that the centring cone is adjustable in a radial direction relative to the tailstock.

3. The device according to claim 1, wherein the centring cone includes a central axial extension, via which the centring cone engages, with a clearance fit, an axial recess disposed in the tailstock.

4. The device according to claim 3, wherein the centring cone further includes an annular groove disposed in the axial extension and that is open towards an outside.

5. The device according to claim 1, wherein the tailstock includes at least three radially extending internal threads structured and arranged to receive a grub screw.

6. The device according to claims 4, wherein: a grub screw engages the annular groove and secures the centring cone to the tailstock in an axial direction; and the tailstock includes at least three radially extending internal threads structured and arranged to receive the grub screw.

4. The device according to claims 4, wherein: the tailstock includes at least three radially extending internal threads structured and arranged to receive a grub screw; a spring and a ball are arranged in front of the grub screw in a screwing-in direction; and the ball, in an installed state, engage the annular groove and centre the centring cone relative to the tailstock.

8. A method for thermally joining a shaft to at least one functional element having a hub for the shaft via a device, the method comprising: at least one of cooling the shaft and heating the at least one functional element; adjusting a centring cone of a tailstock of the device through the hub, the centring cone configured to adjust radially relative to the tailstock and to engage the shaft, the tailstock having an outer diameter that is smaller than an inner diameter of the hub; moving the shaft into engagement with the centring cone of the tailstock via a guide carriage; when the shaft is not coaxially aligned with the hub and is pushed against the at least one functional element, radially adjusting the shaft via radially adjusting the centring cone; fixing the at least one functional element on the shaft via awaiting a temperature equalisation; and removing the shaft and the at least one functional element fixed thereon from the device.

9. A device for positioning a shaft relative to a functional element, comprising: a tailstock having an outer diameter that is smaller than an inner diameter of a hub of the functional element; a centring cone configured to axially engage the shaft; and wherein the centring cone is adjustably connected to the tailstock such that the centring cone is radially adjustable relative to the tailstock.

10. The device according to claim 9, further comprising an air cushion, wherein: the tail stock includes a face-end recess; and the air cushion is disposed at least partially within the face-end recess and engages a rear surface of the centring cone.

11. The device according to claim 9, further comprising a ball bearing, wherein: the tail stock includes a face-end recess; and the ball bearing is disposed at least partially within the face-end recess and engages a rear surface of the centring cone.

12. The device according to claim 11, wherein a diameter of at least one ball of the ball bearing is greater than an axial depth of the face-end recess such that at least a portion of the ball bearing projects axially out of the face-end recess and contacts the rear surface of the centring cone.

13. The device according to claim 9, further comprising at least one of a ball bearing and an air cushion, wherein: the tail stock includes a face-end recess; and the at least one of the ball bearing and the air cushion is disposed at least partially within the face-end recess and engages a rear surface of the centring cone.

14. The device according to claim 13, wherein: the tailstock further includes an axial recess extending through an axial surface of the tailstock that at least partially defines the face-end recess; and the centring cone includes an axial extension disposed within the axial recess of the tailstock with radial clearance.

15. The device according to claim 14, wherein: the tailstock further includes a radial passage extending from an outer circumferential surface of the tailstock to an inner circumferential surface of the tailstock that at least partially defines the axial recess; the centring cone further includes an annular groove disposed in the axial extension; and the radial passage of the tailstock and the annular groove of the centring cone are aligned with one another.

16. The device according to claim 15, wherein: the tailstock further includes a plurality of radially extending internal threads disposed within the radial passage; and the tailstock further includes a grub screw disposed completely within the radial passage and engaging at least some of the plurality of internal threads.

17. The device according to claim 16, wherein the grub screw projects into and engages the annular groove of the axial extension axially securing the centring cone to the tailstock.

18. The device according to claim 15, wherein: the tail stock further includes a ball disposed within the radial passage; and the ball engages the annular groove of the axial extension axially securing the centring cone to the tailstock.

19. The device according to claim 18, wherein: the tailstock further includes a spring disposed within the radial passage; and the spring is configured to pre-centre the centring cone within the axial recess of the tailstock via pressing the ball into engagement with the annular groove.

20. The device according to claim 19, wherein: the tailstock includes a grub screw disposed completely within the radial passage; and the spring is disposed radially between the grub screw and the ball.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] There it shows, in each case schematically,

[0021] FIG. 1 shows a device according to the invention for positioning a shaft relative to at least one functional element comprising a hub for the shaft,

[0022] FIG. 2 shows a sectional representation through a tailstock according to the invention,

[0023] FIG. 3 shows a representation as in FIG. 2, however with another embodiment.

DETAILED DESCRIPTION

[0024] According to FIG. 1, a device 1 according to the invention for positioning a shaft 3 relative to at least one functional element 4 comprising a hub 2 for the shaft 3, for example a cam 4a, comprises a tailstock 5 for the coaxial alignment of the shaft 3 with respect to the hub 2 of the at least one functional element 4. Here, the tailstock 5 according to the invention comprises a radially adjustable centring cone 6 for the shaft 3 and additionally has an outer diameter that is smaller than the inner diameter of the hub 2.

[0025] Here, the centring cone 6 can be mounted in the radial direction 8 relative to the tailstock 6 by way of an air cushion or a ball bearing 7 (see FIGS. 2 and 3).

[0026] With the tailstock 6 according to the invention and the device 1 according to the invention it is possible for the first time, when joining the shaft 3 in the hub 2 of the functional element 4 to bring about a radial yielding of the shaft 3, provided an axis 9 of the shaft 3 does not run coaxially to the axis 10 of the hub 2, but parallel to the same. This helps in particular in reliably avoiding undesirable score marks on a surface of the shaft 3 which would be created if the shaft 3 with its axis 9 parallel to the axis 10 of the hub 2 were to be introduced or pressed into the same.

[0027] Viewing the FIGS. 2 and 3 it is noticeable that the centring cone 6 has a central axial extension 11 via which it engages with clearance fit, i.e. with radial clearance, in an axial recess 12 in the tailstock 5. On the axial extension 11, an annular groove 13 that is open towards the outside can be arranged, via which an axial fixing of the centring cone 6 in the tailstock 5 becomes possible. In the tailstock 5, at least three radially extending internal threads 14 can be provided, in which a grub screw 15 each for axially fixing the centring cone 6 on the tailstock 5 can be screwed. In the installed state, the grub screws 15 directly (see FIG. 2) or indirectly (see FIG. 3) engage in the annular groove 13 on the axial extension side.

[0028] In the embodiment shown according to FIG. 3 a spring 16 and a ball 17 are provided in the screwing-in direction in front of each grub screw 15, wherein the balls 17 in the installed state engage in the annular groove 13 on the axial extension 11 and thereby pre-centre the axial extension 11 and via the same also the centring cone 6.

[0029] The ball bearing 7 according to the FIGS. 2 and 3 is arranged in a face-end recess 18 of the tailstock 6, wherein a diameter of the individual balls of the ball bearing 7 is slightly larger than an axial extension of the recess 18, as a result of which a rotation or a radial clearance of the centring cone 6 relative to the tailstock 5 is made possible.

[0030] Here, joining the functional elements 4 on the shaft 3 takes place as follows:

[0031] Initially, the shaft 3 are/is cooled and/or the functional element 4 heated, as a result of which a thermal joining is possible in the first place. Alternatively, a joining exclusively by means of a press fit is obviously also possible. Following this, the tailstock 5 with its centring cone 6 is moved through the hub 2 of the functional element 4, for example of the cam 4a, wherein in turn the shaft 3 is subsequently moved up against the centring cone 6 of the tailstock 5 by means of a guide carriage 19 (see FIG. 1). Thus, the shaft 3 is pushed up against the functional element 4, wherein upon a parallelism of the axis 9 of the shaft 3 and of the axis 10 of the hub 2 when the shaft 3 meets the hub 2 or the functional element 4 a radial adjusting of the centring cone 6 and thus a radial adjusting of the shaft 3 takes place, so that the axis 9 and 10 subsequently run coaxially, i.e. are identical. Through the comparatively easy radial adjustability of the centring cone 6 it is thus possible that the shaft 3, upon a determined eccentricity, yields relative to the hub 2 as a result of which a formation of score marks through an eccentric pressing-on of the functional element 4 on the shaft 3 can be reliably avoided. After the shaft 3 has been slid into the hub 2 and pending a temperature equalisation the functional element 4 is fixed on the shaft 3. Following this, the shaft 3 can be removed from the device 1 together with the functional element 4 joined thereon.

[0032] With the method according to the invention and the device 1 according to the invention it is thus possible for the first time to make possible a radial yielding of the shaft 3 during the joining in a hub 2 of a functional element 4, as a result of which in particular score marks on the surface of the shaft 3 can be avoided, which would develop if the shaft 3 were to be eccentrically slid into the hub 2. By way of this, elaborate reworking can be avoided in particular.