Arrangement for securing at least one circlip against centrifugal force, which circlip is axially fastened on a rotor shaft of an electrical machine for positional securing, and use of an arrangement of this type

Abstract

An arrangement secures at least one circlip against centrifugal force. The circlip is axially fastened on a rotor shaft of an electrical machine for positional securing. At least one securing element is provided for securing against the centrifugal forces acting on the circlip when the rotor shaft rotates. The at least one securing element is placed onto the rotor shaft by means of a first portion for fastening and, by means of a second portion, is slid at least partially over the circlip and radially secures the circlip.

Claims

1. An electric axle drive comprising: a rotor shaft having a first groove; a first circlip engaged in the first groove; a first securing sleeve having a first portion axially fastened on the rotor shaft and a second portion extending radially over the first circlip to prevent release of the first circlip due to centrifugal forces when the rotor shaft rotates; and a first bearing having a first inner ring axially positioned with respect to the rotor shaft by the first circlip.

2. The electric axle according to claim 1, wherein the first portion of the securing sleeve is pressed onto the rotor shaft with a force fit.

3. The electric axle according to claim 1, further comprising: a second bearing having a second inner ring; a second circlip engaged in a second groove of the rotor shaft to axially position the second inner ring with respect to the rotor shaft; and a second securing sleeve having a third portion axially fastened on the rotor shaft and a. fourth portion extending radially over the second circlip to prevent release of the second circlip due to centrifugal forces when the rotor shaft rotates.

4. The electric axle according to claim 3, further comprising a rotor fixed to the rotor shaft between the first and second bearings.

5. The electric axle according to claim 1, wherein the first securing sleeve has a plurality of openings for engagement of an extraction tool for dismantling.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further features result from the following description and the figures, in which an exemplary embodiment is shown in a simplified manner. It can be seen that:

(2) FIG. 1 shows an intersected view of an arrangement for securing at least one circlip against centrifugal force, which circlip is axially fastened on a rotor shaft of an electrical machine for positional securing,

(3) FIG. 2 shows an enlarged portion from FIG. 1,

(4) FIGS. 3 and 4 show individual views of a securing element of the arrangement from FIGS. 1 and 2,

(5) FIG. 5 shows an intersected view of a securing element from FIGS. 3 and 4,

(6) FIG. 6 shows an enlarged portion from FIG. 5.

DETAILED DESCRIPTION

(7) FIGS. 1 and 2 show an example of an arrangement for securing two circlips 4, 5 axially fastened on a rotor shaft 3 of an electrical machine against centrifugal force. These serve to secure the axial position of two bearings 1, 2 which are arranged on the rotor shaft 3 of the electrical machine and are designed as radial ball bearings and form the rotor shaft bearings. The rotor shaft 3 carries a coaxially arranged rotor 14 of the electrical machine, wherein the inner bearing rings of the bearings 1, 2 are axially secured on the axial outer sides facing away from the rotor by a respective circlip 4, 5. The circlips 4, 5 rest on the axial outer sides of the bearing inner rings of the bearings 1, 2 and each secure them axially. They are each recessed into a securing groove 6, 7 on the outer diameter of the rotor shaft 3 for attachment.

(8) On the outer sides of the circlips 4, 5, a securing element 8, 9 is placed coaxially on the rotor shaft 3 and pressed over the respective circlip 4, 5 so that the securing elements 8, 9 fully encompass the circlips 4, 5 on the outer diameter. In this way, the latter are secured radially by the respective securing element 8, 9 against unwanted opening and loosening due to the effect of centrifugal force when the rotor shaft 3 rotates. As a result, the circlips 4, 5 can be designed for securing the axial position on the rotor shaft 3 as standard external circlips, for example of the Seeger SW type, which can be easily assembled and disassembled without being destroyed in a particularly advantageous manner.

(9) The securing elements 8, 9 are each designed as a securing sleeve which is divided by an annular radial shoulder 10 into two cylindrical portions 11, 12 and in this way forms a Z-shaped longitudinal profile. On a first portion 11, the securing sleeves 8, 9 are pressed coaxially with the inner diameter onto the outer diameter of the rotor shaft 3. With a second portion 12 that is radially widened at the shoulder 10 compared to the first portion 11, the securing sleeves 8, 9 encompass the outer diameter of the circlips 4, 5 with the inner diameter of their axially inner ends. For assembly, the securing sleeves 8, 9 can simply be pressed with their inner axial ends over the outer diameter of the previously assembled circlips 4, 5 when they are pressed onto the rotor shaft 3 until they abut with the end faces of their axially inner ends on the bearing inner rings of the bearings 1, 2 as an assembly stop in an axially annular manner. In this way, it is possible to axially secure the bearings 1, 2 on the rotor shaft 3 using standard circlips 4, which are radially encompassed by the securing sleeves 8, 9 as centrifugal force safeguards.

(10) The securing sleeves 8, 9 each form with the radial shoulder 10 a Z-shaped longitudinal profile as a so-called Z-disc (FIGS. 3 to 6). The shoulder 10 provides the transition between the first portion 11 with the first inner diameter d.sub.1 and the second portion 12 with the expanded second inner diameter d.sub.2. The first inner diameter d.sub.1 is selected so that the first portion 11 forms a press fit with the outer diameter of the shaft 3, while the second inner diameter d.sub.2 is of a size that allows the securing sleeves 8, 9 to slide with the end of the second portion 12 with a slight radial assembly clearance over the outer diameter of the circlips 5, 6 during assembly. In the area of the shoulder 10, a plurality of openings 13 distributed evenly over the circumference are provided, which are designed as radial through bores into which an extraction tool for extracting the securing sleeve 8, 9 from the rotor shaft 3 can engage on the outer diameter. In this way, a non-destructive dismantling of the securing sleeves 8, 9 and the circlips 4, 5 is possible.

(11) The arrangement can be used particularly advantageously in an electric axle drive of a vehicle (FIGS. 1 and 2). Here, the arrangement with the rotor shaft 3 and the electrical machine forms a part of the axle drive. The rotor shaft 3 is radially supported on a housing 15 via the bearings 1, 2 (FIGS. 1 and 2). An output shaft 16 of the axle drive is passed coaxially through the rotor shaft 3, which is designed as a hollow shaft.

(12) List of reference symbols 1 Bearing 2 Bearing 3 Rotor shaft 4 Circlip 5 Circlip 6 Securing groove 7 Securing groove 8 Securing element, securing sleeve 9 Securing element, securing sleeve 10 Shoulder 11 Portion 12 Portion 13 Opening 14 Rotor 15 Housing 16 Output shaft d.sub.1 Inner diameter d.sub.2 Inner diameter