STATOR ARRANGEMENT OF AN ELECTRIC MACHINE AND ELECTRIC MACHINE FOR DRIVING A MOTOR VEHICLE

Abstract

A stator arrangement of an electric machine having a substantially cylindrical stator carrier with a radially inner joining surface and with a radially outer joining surface. A lamination stack is arranged at the inner joining surface, and the stator carrier with the outer joining surface is received by an inner joining surface of a housing of the electric machine. A connection between the stator carrier and the housing is carried out with an interference fit, and one of the joining surfaces of the stator carrier and housing, which cooperate with one another, is formed interrupted in circumferential direction.

Claims

1-8. (canceled)

9. A stator arrangement of an electric machine comprising: a stator carrier that is substantially cylindrical having a radially inner joining surface and a radially outer joining surface; a lamination stack is arranged at the radially inner joining surface; and a housing having an inner joining surface configured to receive the stator carrier with the radially outer joining surface; wherein a connection between the stator carrier and the housing is carried out by an interference fit between the inner joining surface and the radially outer joining surface, and wherein one of the inner joining surface and the radially outer joining surface is formed interrupted in circumferential direction.

10. The stator arrangement according to claim 9, wherein the stator carrier has two outer joining surfaces which are spaced apart from one another axially and which are formed with a larger outer diameter compared to a circumferential area of the stator carrier located axially between these two joining surfaces, and wherein at least one of these two joining surfaces of the stator carrier is interrupted in circumferential direction.

11. The stator arrangement according to claim 10, further comprising: a fluid cooling jacket formed by a circumferential region axially between the inner joining surface and the radially outer joining surface of the stator carrier and housing; and seal arrangements which are closed in circumferential direction are formed between the stator carrier and the housing, the seal arrangements arranged adjacent to one of the two joining surfaces of the stator carrier in each instance.

12. The stator arrangement according to claim 11, wherein one of the mutually cooperating joining surfaces of the stator carrier and housing is interrupted multiple times in circumferential direction and forms at least two joining surface segments.

13. The stator arrangement according to claim 12, wherein the at least two joining surface segments of two joining surfaces of the stator carrier which are axially spaced apart from one another are arranged offset to one another in circumferential direction and/or have a different circumferential extension.

14. The stator arrangement according to claim 9, wherein the housing is a ferrous casting material and the stator carrier is an aluminum casting material.

15. The stator arrangement according to claim 9, wherein the connection of the inner joining surface of the stator carrier to the lamination stack is an interference fit.

16. An electric machine for driving a motor vehicle, comprising: a stator arrangement comprising: a stator carrier that is substantially cylindrical having a radially inner joining surface and a radially outer joining surface; a lamination stack is arranged at the radially inner joining surface; and a housing having an inner joining surface configured to receive the stator carrier with the radially outer joining surface; wherein a connection between the stator carrier and the housing is carried out by an interference fit between the inner joining surface and the radially outer joining surface, and wherein one of the inner joining surface and the radially outer joining surface is formed interrupted in circumferential direction; and a rotor which is rotatably supported relative to the stator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The invention will be described in the following referring to an exemplary embodiment form shown in the drawings.

[0024] The drawings show:

[0025] FIG. 1 is a schematic view of an electric machine with a rotor and a stator arrangement;

[0026] FIG. 2 is a perspective view of a stator carrier of the stator arrangement from FIG. 1; and

[0027] FIG. 3 is a side view of the stator carrier from FIG. 2.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0028] FIG. 1 shows an electric machine 10 for driving a motor vehicle. The electric machine 10 has a stator 14 secured to a machine housing 12 and a rotor 16 arranged radially inwardly thereof and supported so as to be rotatable around an axis A. The electric machine 10 can be formed as a drive unit in a hybrid vehicle for cooperating with an internal combustion engine or, alternatively, used by itself or with further electric machines as drive unit in an electric vehicle. The further construction and principle of operation of the electric machine 10 are not pertinent to the following. The electric machine 10 can operate, for example, as a permanently excited synchronous machine or as an asynchronous machine.

[0029] The stator 14 comprises a substantially cylindrical stator carrier 18 made from an aluminum casting material, two collar-shaped, radially outwardly directed fastening areas 22 being formed thereon at a front end portion 20. The fastening areas 22, which are formed as fastening lugs in the present instance, have through-openings 22a for producing a screw connection 24 to the housing 12. As will be apparent from FIG. 1, a radially inner joining surface 60 is provided at the stator carrier 18, a lamination stack 26 with a stator winding 28 being arranged at the radially inner joining surface 60 in a known manner by an interference fit. Further, a radially outer joining surface 70 is formed at the stator carrier 18. The radially outer joining surface 70 is received by an inner joining surface 50 of the housing 12 of the electric machine 10 and an interference fit is likewise formed with it. Together with the housing 12, which can be produced from a ferrous casting material in the embodiment example described herein, the stator 14 forms a stator arrangement 30.

[0030] Still referring to FIG. 1, a fluid cooling jacket 32 with a cooling channel 34 is provided radially between the stator carrier 18 and the housing 12 for cooling the electric machine 10, as a result of which heat losses can be carried off from the lamination stack 26 in particular. To form the cooling channel 34, the outer joining surface 70 of the stator carrier 18 is interrupted and is accordingly formed of two parts with joining surfaces 710 and 720. In other words, joining surfaces 710, 720 axially enclose the cooling channel 34 and, at least in some portions, have a larger outer diameter compared to it. Webs or fluid guide ribs 36 extending in circumferential direction are provided inside of the cooling channel 34 for the purpose of optimizing the flow of a coolant flowing therein. Seal arrangements 38, 40, which are closed in circumferential direction are formed axially at both sides of the cooling channel 34 for the fluid-tight connection of the stator carrier 18 and housing 12. The seal arrangements 38, 40 are positioned upstream of the aforementioned joining surfaces 710, 720 in each instance in an axial joining direction F of the stator 14 to the housing 12 and respectively comprise an annular groove 38a, 40a at the stator carrier 18 and an annular seal 38b, 40b which is inserted therein and which cooperates with the inner joining surface 50 of the housing 12. It should be noted that the configuration of the joining surfaces 710, 720 and seal arrangements 38, 40 is only shown schematically in FIG. 1. FIG. 2, and FIG. 3 show a more exact configuration of these features.

[0031] The stator carrier 18 is configured to be substantially not rotationally symmetrical by the fastening areas 22, which are formed opposite one another at the center axis A. Accordingly and also owing to the manufacturing tolerances and assembly tolerances, high mechanical stresses can occur locally in an unwanted manner particularly in the mutual connection area of the stator carrier 18 and housing 12. By way of a remedy, it is provided to form at least one of the mutually cooperating joining surfaces 710, 720; 50 of the stator carrier 18 and housing 12 to be interrupted in circumferential direction. An excessive stressing and deformation possibly resulting therefrom at critical positions are prevented by the resulting interference fit of connection partners which is interrupted in circumferential direction.

[0032] As will be seen from FIG. 2, the two joining surfaces 710, 720 which are axially spaced apart from one another are interrupted multiple times in circumferential direction and formed, respectively, with a plurality of joining surface segments 710A; 720A and recesses 710B; 720B located therebetween. The recesses 710B, 720B are realized in this instance by local diameter changes in the casting blank of the stator carrier 18. For the purpose of a spatial homogenization of occurring mechanical stresses, the joining surface segments 710A, 720B of the two joining surfaces 710, 720 are arranged offset to one another in circumferential direction and also formed with a different circumferential extension.

[0033] The interference fit existing between the inner joining surface 60 of the stator carrier 18 and the lamination stack 26 is comparatively noncritical with respect to mechanical stresses due to the spaced spatial position relative to the two fastening areas 22. Therefore, the inner joining surface 60 is formed circumferentially closed, and an outer joining surface 80 of the lamination stack 26 cooperating with the inner joining surface 60 can optionally have corresponding cutouts for absorbing mechanical stresses which may possibly occur. Accordingly, the stator carrier 18 is connected by its radially inner joining surface 60 and its radially outer joining surface 70 by an interference fit to the radially adjoining elements 12, 26 so as to be fixed with respect to rotation relative to it.

[0034] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.