Rotor for an electrical machine, electrical machine, in particular an asynchronous machine for a motor vehicle, and motor vehicle

Abstract

A rotor for an electrical machine with one or a plurality of cooling ducts through which a cooling agent can flow. One end face of the rotor there is provided an annular space, bounded axially inwardly and radially outwardly and joined communicating with the cooling duct or ducts. A cover plate is provided, attached to the end face and bounding the annular space axially outwardly, having a central through-opening for introducing the cooling agent into the annular space.

Claims

1. A rotor for an electrical machine, comprising: one or a plurality of cooling ducts through which a cooling agent can flow, wherein at one end face of the rotor there is provided an annular space, bounded axially inwardly and radially outwardly and joined communicating with the cooling duct or ducts, wherein a cover plate is provided, attached to the end face and bounding the annular space axially outwardly, having a central through-opening for introducing the cooling agent into the annular space by way of an inlet passing through the cover plate and arranged stationary relative to the rotational movement of the rotor, wherein the cooling agent is configured to be collected by gravity in the annular space in a bottom side of the electrical machine and is moved during a rotating operation of the rotor by centrifugal force against a radially outer boundary of the annular space and subsequently into the cooling ducts.

2. The rotor as claimed in claim 1, wherein the outer diameter of the through-opening lies further inward than the cooling duct or ducts.

3. The rotor as claimed in claim 1, wherein the cover plate is secured to the rotor, by force locking, and/or by an adhesive, and/or by integral bonding.

4. The rotor as claimed in claim 1, wherein the cover plate is sealed off in a fastening section by a sealing agent.

5. The rotor as claimed in claim 1, wherein the cover plate on the side facing the annular space has a recess formed concentrically to the through-opening, whose outer diameter bounds the annular space radially outwardly, at least in regions.

6. The rotor as claimed in claim 1, wherein a squirrel cage is provided, by which the annular space is bounded radially outwardly, at least in regions, and/or on which the cover plate is secured.

7. The rotor as claimed in claim 1, wherein a laminated core is provided by which the annular space is bounded axially inwardly and/or radially outwardly at least in regions, and/or through which the cooling duct or ducts extend.

8. An electrical machine for a motor vehicle, comprising a rotor as claimed in claim 1.

9. The electrical machine as claimed in claim 8, wherein a housing with an outlet is provided, through which the cooling agent can be discharged from the inside of the housing after flowing through the rotor.

10. The electrical machine as claimed in claim 8, wherein a stator with at least one winding head is provided, being arranged in such a way that during the rotary operation of the rotor, the cooling agent impinges on the winding head after flowing through the rotor.

11. The electrical machine as claimed in claim 8, wherein at least one intake bringing in the cooling agent and/or at least one nozzle dispensing the cooling agent is or are provided, by which at least one machine component being cooled can be exposed to the cooling agent.

Description

BRIEF DESCRIPTION OF THE FIGURES

(1) Further advantages and details of the invention will emerge from the exemplary embodiments described below as well as on the basis of the drawing. These are schematic representations and they show:

(2) FIG. 1 a cross-sectional representation of an exemplary embodiment of an electrical machine according to the invention; and

(3) FIG. 2 a schematic diagram of an exemplary embodiment of a motor vehicle according to the invention.

DETAILED DESCRIPTION OF THE FIGURES

(4) FIG. 1 shows a cross-sectional representation of an exemplary embodiment of an electrical machine 1 in the form of an asynchronous machine, comprising a housing 2, a stator 3 with several winding heads 4, 5 and a rotor 6, which is coupled to a shaft 7.

(5) The rotor 6 has a laminated core 8 and a squirrel cage 9 comprising a rotor body 10. The squirrel cage 9 comprises a plurality of rotor bars 11, which pass substantially axially through the laminated core 8 and are joined at their respective ends by shorting rings 12. The laminated core 8, moreover, has a plurality of axial cooling ducts 13 passing through it, through which can flow a cooling agent, such as oil, for example, to discharge heat from the interior of the rotor 6.

(6) Moreover, the rotor 6 has a cover plate 15 at one end face 14, which is secured to the rotor body 10. The fastening in the present case is realized at the shorting ring 12 by means of fastening means, which are not shown, such as, for example, screws and/or bolts, or by means of an adhesive or by welding. The cover plate 15 has a central through-opening 16 as well as a recess 17 formed on the side facing the rotor body 10, producing a step in the cover plate 15. In this way, an annular space 18 is formed, bounded axially inwardly by the laminated core 8, radially outwardly in regions by the inner peripheral wall of the shorting ring 12 and the outer peripheral wall of the recess 17, and axially outwardly by the cover plate 15, which space is joined communicating with the cooling ducts 13. Thus, the annular space 18 forms an inwardly open radial groove.

(7) By means of an intake 20 passing through a cover 19 of the housing 2, for example, in the form of a pipe or flexible tubing, the cooling agent can be introduced into the electrical machine 1. This agent flows by gravity in the direction of a bottom side 21 of the electrical machine 1 into the annular space 18 and is moved in the rotating operation of the rotor 6 by centrifugal force against the radially outer boundary of the annular space 18. Thanks to the contact with the cooling agent, oppositely situated fastening regions of the rotor body 10 and the cover plate 15 are sealed off from each other by a sealing means, which is preferably a liquid sealant and/or an O-ring. The cooling agent collecting in the annular space 18 is directed with increasing inflow into and through the cooling ducts 13, producing a continuous flow for the cooling of the rotor 6.

(8) After flowing through the cooling ducts 13, the cooling agent exits the cooling ducts at the opposite end face 22 and is hurled by the rotational movement of the rotor 6 in the direction of the winding heads 4, which are likewise cooled by the impinging cooling agent. This then flows from the winding heads 4 or immediately after leaving the cooling ducts 13 to the bottom side 21. Moreover, the housing 2 has an outlet 23, through which the cooling agent leaves the interior of the electrical machine 1. The emerging cooling agent is then taken to an external cooler in order to produce a cooling circuit and then is once more taken to the intake 20.

(9) Furthermore, other intakes of cooling agent into the interior of the electrical machine 1 (not shown) are provided for the cooling of other regions under thermal stress. Nozzles directed at these regions can be provided at the inlets or at the intake 20, from which the cooling agent emerges and impinges on corresponding machine components under thermal stress. A discharging of the cooling agent so dispensed is likewise made possible by the outlet 23 on the bottom side.

(10) According to another exemplary embodiment, the radially outer boundary of the annular space 18 is formed entirely by the rotor body 10, especially by the shorting ring 12. In an alternative exemplary embodiment in which the squirrel cage 9 can be eliminated entirely, the annular space is bounded on the radial outside entirely by the stepped cover plate 15. This is appropriate when the electrical machine 1 is a synchronous machine. In the context of another exemplary embodiment, the annular space 18 may be bounded on the radial outside entirely or in regions by the laminated core 8.

(11) FIG. 2 shows a schematic diagram of an exemplary embodiment of a motor vehicle 24 with an electrical machine 1 according to one of the preceding exemplary embodiments. The electrical machine 1 is connected to a drive train 25 of the motor vehicle 24 for the total or partial drive of the motor vehicle 1.