METHOD FOR PRODUCING A ROTOR UNIT

Abstract

The invention relates to a method for producing a rotor unit (10) of an electric motor, in particular a canned motor or the like, for driving a pump wheel of a pump and to a pump, the rotor unit being composed of a rotor (11), a shaft (12), a thrust washer (13) and sliding bearings (14, 15), the rotor being formed by a permanent magnet (22) or a shading coil, the rotor and the thrust washer being attached to the shaft, the shaft being rotatably mounted at one end (16) of the shaft and at the thrust washer by means of respective sliding bearings, the thrust washer being in contact with an axial lateral surface (21) of one of the sliding bearings (14), wherein the shaft is made from a fiber-reinforced polymer material.

Claims

1. A method for producing a rotor unit (10) of an electric motor, in particular a canned motor or the like, for driving a pump wheel of a pump, the rotor unit being composed of a rotor (11), a shaft (12), a thrust washer (13) and sliding bearings (14, 15), the rotor being formed by a permanent magnet (22) or a shading coil, the rotor and the thrust washer being attached to the shaft, the shaft being rotatably mounted at one end (16) of the shaft and at the thrust washer by means of respective sliding bearings, the thrust washer being in contact with an axial lateral surface (21) of one of the sliding bearings (14), characterized in that the shaft is produced from a fiber-reinforced polymer material.

2. The method according to claim 1, characterized in that the thrust washer (13) is produced from a fiber-reinforced polymer material.

3. The method according to claim 1, characterized in that the thrust washer (13) is co-molded with the shaft (12).

4. The method according to claim 1, characterized in that the production from the fiber-reinforced material takes place by transfer molding or by injection molding.

5. The method according to claim 4, characterized in that the permanent magnet (22) or the shading coil is placed in a mold and is joined with the shaft (12) by transfer molding or injection molding in the mold.

6. The method according to claim 4, characterized in that the permanent magnet (22) or the shading coil is enclosed, preferably fully encased, in the polymer material.

7. The method according to claim 4, characterized in that the shaft (12) is placed in a mold and is joined with the permanent magnet (22) by transfer molding or injection molding in the mold, the permanent magnet being produced from a thermoplastic or thermosetting magnetic compound.

8. The method according to claim 4, characterized in that the shaft and the permanent magnet are produced in the mold at the same time by two-component injection molding.

9. The method according to claim 7, characterized in that the permanent magnet (22) is magnetized in the mold.

10. The method according to claim 4, characterized in that the fibers are oriented parallel to a surface of the shaft (12) and/or at a flat angle relative to the surface during transfer molding or injection molding.

11. The method according to claim 1, characterized in that the sliding bearings (14, 15) are realized as bearing bushes made of carbon, preferably graphite, phenolic resin-impregnated graphite, carbonized graphite-filled phenolic resin compound, fiber-reinforced polymer or ceramics.

12. The method according to claim 1, characterized in that carbon fibers or glass fibers, preferably as short fibers, are used as fibers.

13. The method according to claim 1, characterized in that a thermoset, preferably phenolic resin, epoxy resin, polyester resin or polycyclopentadiene resin, or a thermoplastic, preferably polypropylene, polyphenylene sulfide or polyether ether ketone, is used as the polymer material.

14. The method according to claim 1, characterized in that another filler, preferably graphite, molybdenum sulfide, tungsten disulfide, polytetrafluoroethylene, glass bubbles and/or mineral additives, is added to the polymer material.

15. The method according to claim 1, characterized in that the shaft (12) is machined at bearing surfaces (23, 24, 25).

16. The method according to claim 1, characterized in that a friction coefficient of 0.15 to 0.05, preferably 0.1 to 0.07, is formed between bearing surfaces (23, 24, 25) of the shaft (12) and sliding bearings (14, 15).

17. A pump comprising an electric motor, in particular a canned motor or the like, for driving a pump wheel of the pump, the electric motor being composed of a stator, a rotor (11), a shaft (12), a thrust washer (13) and sliding bearings (14, 15), the rotor being formed by a permanent magnet (22) or a shading coil, the rotor, the thrust washer and the pump wheel being attached to the shaft, the shaft being rotatably mounted at one end (16) of the shaft and at the thrust washer by means of respective sliding bearings, the thrust washer being in contact with an axial lateral surface (21) of one of the sliding bearings, characterized in that the shaft is made of a fiber-reinforced polymer material.

18. A use of a fiber-reinforced polymer material for forming a shaft (12) of a canned motor of a pump, in particular a circulation pump or the like.

Description

[0028] Hereinafter, an embodiment of the invention will be explained in more detail with reference to the FIGURE.

[0029] The FIGURE shows a longitudinal-section view of a rotor unit 10 of a canned motor (not shown) of a pump. Rotor unit 10 is composed of a rotor 11, a shaft 12, a thrust washer 13 and sliding bearings 14, 15. Thrust washer 13 is co-molded with shaft 12, shaft 12 thus forming thrust washer 13. Shaft 12, and with it thrust washer 13, consists of a fiber-reinforced polymer material, shaft 12 having been produced in a mold by transfer molding or injection molding. Sliding bearing 15 is disposed at one end 16 of shaft 12, sliding bearing 14 being disposed on a portion 17 of shaft 12. Bearing gaps (not illustrated) which allow rotor 11 to rotate about a longitudinal axis 18 of rotor unit 10 are formed between each of sliding bearings 14 and 15 and shaft 12. Sliding bearings 14 and 15 consist primarily of a carbonaceous material. Sliding bearing 14 simultaneously serves to axially support shaft 12 because a contact surface 20 of thrust washer 13 is in contact with a lateral surface 21 of sliding bearing 14. A pump wheel (not shown) is attached to a front end 19 of shaft 12.

[0030] Rotor 11 is formed by a permanent magnet 22 which has been produced from a now set thermosetting magnetic compound or a compound containing magnetizable particles. Alternatively, permanent magnet 22 can be made of a sintered magnet, hard ferrite or a rare-earth magnet. Shaft 12 is material-bonded to permanent magnet 22, permanent magnet 22 having been placed in a mold (not shown) and shaft 12 having been formed together with thrust washer 13 in the mold by transfer molding or injection molding. Furthermore, bearing surfaces 23, 24 and 25 of shaft 12 were after-treated and assembled with sliding bearings 14 and 15 by insertion.