TRANSPORT COVER, ARRANGEMENT WITH A TRANSPORT COVER AND WITH AN ELECTRIC MACHINE AND METHOD FOR OPERATING AN ELECTRIC MACHINE

Abstract

Transport cover (3), configured to be mounted to an electric machine (2), the electric machine (2) having a housing (4) with an end shield (5), a rotatable shaft (6) extending along a rotation axis (7) through the end shield (5) out of the housing (4) and a bearing (8) supporting the shaft (6) and mounted to the end shield (5), the transport cover (3) comprising a fixation section (11) fixable at the housing (4), a cover section (12) forming an accommodation space (14) for a stub (6a) of the shaft (6), and a through-hole (15) allowing to apply a lubricant from the outside of the transport cover (3) to the bearing (8) in a mounted state, in which the fixation section (11) is fixed at the housing (4).

Claims

1. A transport cover, configured to be mounted to an electric machine, the electric machine having a housing with an end shield, a rotatable shaft extending along a rotation axis through the end shield out of the housing and a bearing supporting the shaft and mounted to the end shield, the transport cover comprising: a fixation section fixable at the housing a cover section forming an accommodation space for a stub of the shaft; and through-hole allowing to apply a lubricant from the outside of the transport cover to the bearing in a mounted state, in which the fixation section is fixed at the housing .

2. The transport cover according to claim 1, wherein the cover section has a radial recess that at least partially surrounds the through-hole.

3. The transport cover according to claim 2, further comprising a plate-shaped section, in which the through-hole is formed and which extends into the recess.

4. The transport cover according to claim 3, wherein the plate-shaped section is configured to extend substantially perpendicularly to the rotation axis in the mounted state.

5. The transport cover according to claim 1, further comprising: an attachment section configured to abut on the end shield in the mounted state.

6. The transport cover according to claim 5, further comprising a sealing ring, configured to be arranged between the end shield and the attachment section in the mounted state.

7. The transport cover according to claim 6, wherein the attachment section has a cylinder-shaped member configured to extend into the end shield in the mounted state, wherein the sealing ring is arranged between the cylinder-shaped member and the end shield.

8. The transport cover according to claim 1, claims, wherein the cover section has at least partially the shape of a cone or of a truncated cone.

9. The transport cover according to claim 1, wherein the fixation section comprises two flange members each configured to extend radially with respect to the rotation axis in the mounted state.

10. The transport cover according to claim 1, wherein the fixation section comprises two fixation means that are arranged such that an imaginary line between them does not intersect with the rotation axis in the mounted state, and/or one or multiple fixation elements configured to fixate the fixation section by a snap-fit to the housing.

11. The transport cover according claim 1, further comprising a plug configured to close the through-hole.

12. An arrangement, comprising: a transport cover according to claim 1; and an electric machine having a housing with an end shield, a rotatable shaft extending along a rotation axis through the end shield out of the housing and a bearing supporting the shaft and mounted to the end shield, the transport cover being mounted to the electric machine.

13. A method for operating an electric machine, the electric machine comprising a housing with an end shield, a rotatable shaft extending along a rotation axis through the end shield out of the housing and a bearing supporting the shaft and mounted to the end shield, the method comprising: mounting a transport cover according to claim 1 to the end shield such that the stub of the shaft is disposed in the accommodation space of the transport cover; applying a lubricant through the through-hole to the bearing; and rotating the shaft in the mounted state of the transport cover after having applied the lubricant.

14. The method according to claim 13, further comprising: closing the through-hole using a plug after having applied the lubricant through the trough-hole and before rotating the shaft in the mounted state of the transport cover.

15. The method according to claim 13, further comprising after rotating the shaft: removing the transport cover; and mounting a gear box to the electric machine.

Description

[0038] Further details and advantages are described in the following, wherein reference is made to the attached drawings. The drawings are schematic drawings and show:

[0039] FIG. 1 a plan view on a first embodiment of the arrangement according to the invention;

[0040] FIG. 2 a detailed perspective view on the transport cover according to the first embodiment;

[0041] FIG. 3 a cross-sectional view corresponding to a sectional plane III-III in FIG. 1;

[0042] FIG. 4 a cross-sectional view corresponding to a sectional plane IV-IV in FIG. 1;

[0043] FIG. 5 a plan view on a second embodiment of the arrangement according to the invention;

[0044] FIG. 6 a perspective view on the transport cover according to the second embodiment;

[0045] FIG. 7 a cross-sectional view corresponding to a sectional plane VII-VII in FIG. 5; and

[0046] FIG. 8 a cross-sectional view corresponding to a sectional plane VIII-VIII in FIG. 5.

[0047] FIG. 1 to FIG. 4 show a first embodiment of the arrangement 1 with an electric machine 2 and a transport cover 3, wherein FIG. 1 is a plan view on the arrangement 1, FIG. 2 is detailed perspective view on the transport cover 3, FIG. 3 is a cross-sectional view corresponding to a sectional plane Ill-Ill in FIG. 1 and FIG. 4 is another sectional view corresponding to a sectional plane IV-IV in FIG. 1.

[0048] As shown in FIGS. 1 and 2, the electric machine 2 comprises a housing 4 with an end shield 5 being a drive end (DE) shield. Furthermore, as can be seen in FIG. 3, the electric machine 2 comprises a rotatable shaft 6 extending along a rotation axis 7 through the end shield 5 out of the housing 4 and a bearing 8 supporting the shaft 6. The bearing 8 is mounted to the end shield 5.

[0049] The electric machine 2 is intended to be attached to a separate gear box (not shown), which may be mounted by means of a flange connection to the housing 4. Thereto, a plurality of fixation means 9 formed by through-holes may be provided in a flange section 10 of the housing 4. When the electric machine 2 is manufactured at a manufacturing site that is different from the one, where the gear box is attached to the electric machine, a stub 6a (see FIG. 3) of the shaft 6, which extends out of the housing 4, is protected from mechanical damages by means of the transport cover 3.

[0050] The transport cover 3 comprises a fixation section 11 that is fixable at the housing 4 and shown in a mounted state, in which the fixation section 11 is fixed at the housing. Furthermore, the transport cover 3 comprises a cover section 12, which may have the shape of a truncated cone as shown in FIGS. 1 and 2 and forms an accommodation space 14 for the stub 6a, as can be seen in FIG. 3.

[0051] Additionally, the transport cover 3 comprises a through-hole 15 that allows to apply a lubricant, e.g. oil, from the outside of the transport cover 3 to the bearing 8 in the mounted state. In particular, the lubricant can be applied to the bearing 8 before an end-of-line test of the electric machine 2 before transporting it to the manufacturing site, where the gear box is attached. The transport cover 3 may remain in its mounted state during an end-of-line test, so that lubricant, which hurls away due a rotation of the shaft 6 within the end-of-line test, cannot cause dirt outside of the transport cover 3.

[0052] For the present embodiment, the transport cover 3 comprises a plug 16 made, for instance, from rubber. The plug 16 may comprise an annular sealing nose 17, and is configured to close the through-hole 15. The plug 16 can be removed when applying the lubricant and close the through-hole 15 thereafter, particularly during the end-of-line test and the transport.

[0053] As can be seen in detail in FIG. 2, the cover section 12 may have a radial recess 18 that at surrounds the through-hole 15. By providing the recess 18 the through-hole 15 can be positioned at a position that corresponds to the radial position of the part of the bearing 8, where the lubricant can be applied effectively. Moreover, the transport cover 3 may comprise a plate-shaped section 19, in which the through-hole is formed and which extends into the recess 18. The plate-shaped section 19 extends substantially perpendicularly to the rotation axis 7. Furthermore, the through-hole 15 may be surrounded by an annular section 20 that extends from the plate-shaped section 19 into a direction opposite to the bearing 8. The annular section 20 supports the plug 16 and forms a counterface for the sealing nose 17.

[0054] Preferably, the transport cover 3 also comprises an attachment section 21 configured to abut on the end shield 5 in the mounted state. The cover section 12 may extend from the attachment section 21 away from the end shield 5 in the mounted state. As can be seen in FIG. 2, in the axial direction the recess 18 does not extend to the position, where the attachment section 21 contacts the cover section 12. Thereby, the plate-shaped section 19 may form a socket being axially displaced from an abutting position of the attachment section 21 in the mounted state.

[0055] A sealing member 22 of the transport cover 3 may be configured to be arranged between the end shield 5 and the attachment section 21. The attachment section 21 may have a cylinder-shaped member 23 configured to extend into the end shield 5 in the mounted state, wherein the sealing member 22 is arranged between the end shield 5 and the attachment section 21 in the mounted state. Exemplarily, the sealing member 22 is formed by sealing ring arranged in an annular groove 24 of the attachment section 21 or the cylinder-shaped member 23, respectively. Furthermore, the attachment section 21 may have an annular collar 25 that extends away from the end shield 5 in the mounted state.

[0056] As can be seen best in FIG. 2 and FIG. 4, the fixation section 11 may comprise two flange members 26, 27 each configured to extend radially with respect to the rotation axis 7 in the mounted state. In the present embodiment, the flange members 26, 27 exemplarily extend from the collar 25 of the attachment section 21. Also, the fixation section 11 may comprise two fixation means 28, 29, each exemplarily formed by through-holes in a respective flange member 26, 27. As depicted in FIG. 1, the fixation means 28, 29 may arranged such that an imaginary line 30 between them does not intersect with the rotation axis 7 in the mounted state. This asymmetrical arrangement of the fixation means 28, 29 prevents that a worker mistakenly mounts the transport cover 3 turned by 180° to the end shield 5, according to the concept of “poka yoke”.

[0057] Further, the fixation means 28, 29 may be arranged such that their positions match with the positions of two of the fixations means 9 of the housing 4. Thus, no additional fixation means beneath those for attaching the gearbox are needed to fixate the transport cover 3.

[0058] With reference to FIG. 2 and FIG. 4, the transport cover 3 may comprise two fixation elements 31, 32 configured to fixate the fixation section 11 by means of a snap-fit to the housing 4. In the present embodiment, the fixation elements 31, 32 are configured to extend through the fixation means 28, 29 of the fixation section 11 into the fixation means 9 of the housing 4 and to form a connection there.

[0059] The transport cover 3 may comprise a plurality of stiffener members 33 formed with the cover section 12 and the fixation section 11. The stiffener members 33 may be additionally be formed with attachment section 21. Further stiffener members 34 may be formed with the attachment section 21, particularly its collar 25, and the fixation section 11, particularly one of its flange members 26, 27,

[0060] FIG. 5 to FIG. 8 show a second embodiment of the arrangement 1, wherein FIG. 5 is a plan view on the arrangement, FIG. 6 is a perspective view on the transport cover 3, FIG. 7 is a cross-sectional view corresponding to a sectional plane VII-VII in FIG. 5 and FIG. 8 is a cross-sectional view corresponding to a sectional plane VIII-VIII in FIG. 5. In the following only the significant differences of the second embodiment in comparison to the first embodiment are described, wherein identical or equivalent components are provided with the same reference numerals.

[0061] According to the second embodiment the plate-shaped section 19 may be formed integrally with the attachment section 21, Therein, the recess 18 may extend in axial direction until the attachment section 21. Furthermore, as it is apparent from FIG. 6 and FIG. 7, a collar of attachment section 21 may be omitted. Moreover, the flange members 26, 27 may extend directly from the cover section 12.

[0062] An embodiment of a method for operating the electric machine 2 is described in the following:

[0063] As a first step the transport cover 1 according to any of afore-mentioned embodiments is mounted to the end shield 5 such that the stub 6a of the shaft 6 is disposed in the accommodation space 14 of the transport cover 3. Next, the plug 16 may be removed from the through-hole 15. Then, the lubricant is applied through the through-hole 15 to the bearing 8, Thereafter, the plug 16 may be disposed into the through-hole 15 so as to close it. As a next step the shaft 6 is rotated, e.g. with 14,000 to 18,000 revolutions per minute, in the mounted state of the transport cover 3 in order to perform the end-of-line test.

[0064] When the end-of-line test is completed, the electric machine 2 and the transport cover 3 in the mounted state may be transported. Particularly after the electric machine 2 has arrived at another manufacturing site, the transport cover 3 is removed. The end shield 5 may be cleaned from remaining lubricant, if necessary, As a next step, the gear box is mounted to the electric machine 2.