Electric compressor and method for producing an electric compressor

Abstract

An electric compressor for compressing a gas, particularly configured for use in a motor vehicle, comprising a control unit, an electric motor controlled by the control unit, a compressor wheel driven by the electric motor, and a housing at least partially surrounding the electric motor. The housing is produced by an encapsulation method such that a cooling structure is formed integrally with the housing, in particular within the housing, for ensuring cooling of the electric motor and of the control unit. A method for producing the electric compressor of this kind is also disclosed.

Claims

1. An electric compressor for compressing a gas and configured for use in a motor vehicle, the electric compressor comprising: a control unit; an electric motor electrically connected to and controlled by the control unit, the electric motor including a stator extending about a center axis and having a continuous outer circumference; the outer circumference of the stator defining a plurality of recesses extending radially inwardly and axially; a compressor wheel coupled with the electric motor for being driven by the electric motor; and a housing surrounding the outer circumference of the stator of the electric motor and defining a plurality of cooling ducts for cooling the electric motor and the control unit, wherein the housing defines radially interior surfaces and radially outer surfaces of the cooling ducts, and wherein the housing extends radially into the plurality of recesses such that the cooling ducts are each received in one of the recesses of the stator; wherein a plurality of capacitors are each located circumferentially between two adjacent recesses of the plurality of recesses of the stator.

2. The electric compressor according to claim 1, wherein the compressor wheel and the electric motor are arranged coaxially on a shaft.

3. The electric compressor according to claim 1, wherein the housing at least partially encloses the control unit.

4. The electric compressor according to claim 1, wherein a number of the cooling ducts corresponds to a number of the plurality of recesses of the stator.

5. The electric compressor according to claim 4, wherein the cooling ducts extend axially along the recesses of the stator.

6. The electric compressor according to claim 1, wherein the cooling ducts are formed at least partially along a rear side of the control unit.

7. A method for producing an electric compressor according to claim 1, wherein the housing is produced in such a way by means of an encapsulation method that the cooling ducts are formed integrally with the housing, in particular in the housing.

8. The method according to claim 7, wherein the cooling ducts are formed by means of internal-pressure injection moulding or by the introduction of at least one moulding body.

9. The method according to claim 8, wherein the moulding body is removed mechanically, by a chemical reaction, or by a thermal reaction after the encapsulation process.

10. An electric compressor for compressing a gas and configured for use in a motor vehicle, the electric compressor comprising: a control unit; an electric motor electrically connected to and controlled by the control unit, the electric motor including a stator extending about a center axis and having an outer circumference; the outer circumference of the stator defining a plurality of recesses extending radially inwardly and axially; a compressor wheel positioned about the center axis and coupled with the electric motor for being driven by the electric motor; and a housing radially surrounding the stator and defining a plurality of axially extending cooling ducts, the housing extending into the recesses of the stator such that the cooling ducts are each received by one of the recesses of the stator for cooling the electric motor and the control unit, and wherein an entire outer perimeter of each of the cooling ducts is defined by the housing; wherein a plurality of capacitors are each located circumferentially between two adjacent recesses of the plurality of recesses of the stator.

11. The electric compressor according to claim 10, wherein the outer perimeter of each of the cooling ducts includes a radially interior surface defined by the housing, a radially outer surface defined by the housing, and a pair of side edges extending between the radially interior and outer surfaces and defined by the housing.

12. The electric compressor as set forth in claim 11 wherein the stator includes a plurality of windings being circumferentially spaced from one another, and wherein the recesses each extend across at least a majority of a circumferential distance between two adjacent windings of the plurality windings.

13. The electric compressor as set forth in claim 10 wherein the cooling ducts are each located circumferentially between two adjacent capacitors of the plurality of capacitors and wherein each of the cooling ducts are at least partially radially aligned with the capacitors.

14. An electric compressor for compressing a gas and configured for use in a motor vehicle, the electric compressor comprising: a control unit; an electric motor electrically connected to and controlled by the control unit, the electric motor including a stator extending about a center axis and having an outer circumference; the outer circumference of the stator defining a plurality of recesses extending radially inwardly and axially; a compressor wheel positioned about the center axis and coupled with the electric motor for being driven by the electric motor; and a housing radially surrounding the stator and defining a plurality of axially extending cooling ducts, the housing extending into the recesses of the stator such that the cooling ducts are each received by one of the recesses of the stator for cooling the electric motor and the control unit, and wherein an entire outer perimeter of each of the cooling ducts is defined by the housing; wherein the stator includes a plurality of windings being circumferentially spaced from one another, and wherein the recesses each extend across at least a majority of a circumferential distance between two adjacent windings of the plurality windings; wherein the stator includes a stator carrier radially surrounding the plurality of windings and defining the outer circumference of the stator and the recesses, and wherein the stator carrier defines a plurality of projections extending radially outwardly, each circumferentially between two adjacent recesses of the plurality of recesses.

15. The electric compressor as set forth in claim 14 wherein a plurality of capacitors are each located circumferentially in alignment with and radially outwardly of one of the plurality of projections, wherein the cooling ducts are each located circumferentially between two adjacent capacitors of the plurality of capacitors, and wherein each of the cooling ducts are at least partially radially aligned with the capacitors.

Description

DRAWINGS

(1) The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

(2) The invention is described below by way of example with reference to the drawings.

(3) FIG. 1 shows a longitudinal section through an electric compressor according to the invention.

(4) FIG. 2 shows one perspective view of a control unit and of a stator of an electric motor of an electric compressor according to the invention.

(5) FIG. 3 shows a perspective detail view from FIG. 3.

(6) FIG. 4 shows a perspective view of a housing, including a control unit, and of a stator of an electric motor of an electric compressor according to the invention.

(7) FIG. 5 shows FIG. 4 in a longitudinal section.

(8) FIG. 6 shows FIG. 4 in a cross section.

(9) FIG. 7 shows FIG. 4 in another cross section at the interface between the electric motor and the control unit.

(10) FIG. 8 shows a plan view of the control unit according to FIG. 4.

(11) FIG. 9 shows FIG. 4 in another longitudinal section, including arranged mould parts.

(12) FIG. 10 shows a perspective illustration of the electric compressor according to the invention.

DESCRIPTION

(13) One or more example embodiments of an electric compressor are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.

(14) An electric compressor, shown in FIG. 1, is configured to include a control unit 2, an electric motor 3, a compressor wheel 4 and a housing 6 (FIG. 4). The electric motor 3 can be controlled by means of the control unit 2 and is used for selective driving of the compressor wheel 4. The compressor wheel 4 and the electric motor 3 are arranged coaxially on a common shaft 5, wherein the shaft 5 is formed along a central axis of rotation 13 of the electric motor 3. The compressor wheel 4 is arranged in a compressor wheel housing 17. The compressor wheel housing 17 is formed by the joining together of a first compressor wheel housing part 18 and a second compressor wheel housing part 19.

(15) The electric motor 3 is designed as an internal-rotor electric motor and has a rotor 14 with permanent magnets and a stator 9 with six stator windings 15. The electric motor 3 is used to drive the compressor wheel 4. The rotor 14 of the electric motor 3 is arranged for conjoint rotation on the shaft 5. The compressor wheel 4 is arranged for conjoint rotation on the shaft 5. The rotational energy generated by the electric motor 3 is transferred to the compressor wheel 4 via the common shaft 5.

(16) The control unit 2 is arranged coaxially with the electric motor 3 along the central axis of rotation 13 of the electric motor 3 and is connected electrically to the electric motor 3, more precisely to the stator windings 15 of the stator 9 of the electric motor 3, by at least one connecting element 16.

(17) FIG. 2 shows a perspective view of a control unit 2 and of a stator 9 of an electric motor 3 of an electric compressor 1 according to the invention. The control unit 2 represents the power and signal electronics for the electric motor 3 and comprises a circuit board 20, on which various electronic modules 21 are arranged, in this case including capacitors 22, and in this case likewise two plug connectors 23. The two plug connectors 23 are, on the one hand, a power connector and, on the other hand, a signal connector.

(18) The stator 9 of the electric motor 3 comprises six individual stator segments 24, six stator windings 15, which are arranged on the stator segments 24, and a stator carrier 25. The stator carrier 25 is of annular design and surrounds the stator segments 24 and the stator windings 15. The outer circumference of the stator carrier thus forms the outer circumference 10 of the stator 9 of the electric motor 3. On the outer circumference 10, the stator carrier 25 has a plurality of uniformly spaced, axially extending recesses 11. The direction indication axially refers to a direction along the central axis of rotation 13 of the electric motor 3. In the region between each of the recesses 11, the stator carrier 25 has projections 26 in the region of a side facing away from the control unit 2.

(19) The projections 26 extend radially over a part of the outer circumference 10 of the stator carrier 25 in the region between two recesses 11. The direction indication radially refers to a direction normal to the central axis of rotation 13 of the electric motor 3. The projections 26 are embodied in such a way that the capacitors 22 of the control unit 2 can extend axially along the stator 9 as far as the projections 26 in the region between two recesses 11. In this way, a compact and robust arrangement of the electric motor 3 and of the control unit 2 is achieved.

(20) The perspective view, already described by means of FIG. 2, of the control unit 2 and of the stator 9 of an electric motor 3 without the stator carrier is shown in FIG. 3. Here, the six stator windings 15 of the stator can be seen. The rotor 14 (not shown; FIG. 1) arranged on the shaft 5 is arranged in the region of the central opening 27 of the stator 9.

(21) FIG. 4 shows the perspective view, already described by means of FIG. 2 and FIG. 3, of the control unit 2 and of the stator 9 of an electric motor 3 with the housing of the electric compressor 1 according to the invention. FIG. 5 shows a longitudinal section through the perspective illustration in FIG. 4. The stator 9 of the electric motor 3 and the control unit 2 are arranged in the housing 6 of the electric compressor 1 according to the invention. The housing 6 is produced by an encapsulation method, wherein a cooling structure is formed in the housing 6, integrally with the housing 6.

(22) The cooling structure 7 has a plurality of cooling ducts 8, wherein the cooling ducts 8 are formed around the outer circumference 10 of the stator of the electric motor 3, the cooling ducts 8 extending, in particular, axially along the recesses 11 of the stator (of the stator carrier 25). The cooling structure 7 of the illustrative electric compressor 1 under consideration has a number of cooling ducts 8 corresponding to the number of recesses 11 of the stator 9, i.e. six cooling ducts 8.

(23) The cooling ducts 8 each extend radially from the recess 11 on the outer circumference 10 of the stator 9 into the region of the capacitors 22 of the control unit 2, which extend axially along the outer circumference 10 of the stator 9, in each case between two recesses 11. Here, the radial extent of the projections 26 is shorter than the radial extent of the cooling ducts 8. The cooling ducts 8 serve not only to cool the electric motor 3 but are also used to cool the capacitors 22. Via the cooling duct passages 28, the rear side 34 of the control unit 2, namely that side of the control unit 2 which faces away from the electric motor 3, is also cooled.

(24) A first cross section through the perspective view, shown in FIG. 4, of the control unit 2 and of the stator 9 of an electric motor 3, together with the housing 6 of the electric compressor 1 according to the invention, is shown in FIG. 6. Here, it is possible to see, in particular, the distribution of the projections 26, of the capacitors 22 and of the cooling ducts 8 along the outer circumference 10 of the stator carrier 25.

(25) FIG. 7 shows another cross section through the perspective view, shown in FIG. 4, of the control unit, together with the housing 6 of the electric compressor 1 according to the invention, at the interface between the electric motor 3 and the control unit 2. Here too, the distribution of the capacitors 22 and of the cooling ducts 8 along the outer circumference 10 of the stator carrier 25 can be seen. Moreover, one of three connecting elements 16, by means of which the electric motor 3 is connected electrically to the control unit 2, is shown. The connecting elements 16 represent the electrical interface between the electric motor 3, more precisely the stator windings 15, and the control unit 2.

(26) A plan view of control unit 2, as it is shown in FIG. 4, is shown in FIG. 8. In the region of the control unit 2, the cooling structure 7 of the electric compressor 1 according to the invention has two cooling-duct passages 28, which serve to cool the rear side 34 of the control unit 2, namely that side of the control unit 2 which faces away from the electric motor 3, wherein in this way the cooling of further high-load electronic modules 21 of the control unit 2 is accomplished, in particular. The cooling structure 7 is supplied with cooling fluid via a cooling-fluid inlet 32 and a cooling-fluid outlet 33.

(27) The method according to the invention for producing the electric compressor 1 described comprises the production of the housing 6 by means of an encapsulation method, wherein the encapsulation method is performed in such a way that the cooling structure 7, that is to say in this case the cooling ducts 8, is (are) formed integrally with the housing 6, in the housing 6. Here, the cooling structure 7 is produced by introducing moulding bodies 12.

(28) FIG. 9 shows a longitudinal section through the perspective view, shown in FIG. 4, with inserted moulding bodies 12 and an opening moulding body 29. After the encapsulation process, the moulding bodies 12 and the opening moulding body 29 are removed mechanically.

(29) The moulding bodies 12 and the opening moulding body 29 may also be removed by a chemical reaction and/or by a thermal reaction after the encapsulation process along with, or without the mechanical removal process.

(30) As shown in FIG. 9, the moulding bodies 12 serve to form the cooling ducts 8 of the cooling structure 7 and, in accordance with the illustrative embodiment under consideration, have a trapeziform cross section, resulting in the formation of trapeziform cooling ducts 8 in the housing. However, the moulding bodies 12 and thus the cooling ducts 8 can be configured in any desired shape. The opening moulding body 29 serves to form the central opening 27 and has a substantially circular cross section, resulting in a circular central opening 27 for the arrangement of the shaft 5 and of the rotor 14.

(31) In this illustrative embodiment, the stator 9 and the control unit 2 are completely encapsulated by means of the encapsulation method, with only those points at which the moulding bodies 12 and the opening moulding body are inserted remaining free, thus forming the cooling structure 7 and also the central opening 27.

(32) FIG. 10 shows the illustrative electric compressor 1 according to the invention, shown in FIG. 1 in a longitudinal section, in a perspective view, wherein in this case a compressor gas inlet 30 and a compressor gas outlet 31 are formed on the compressor wheel housing 17. The assembly of the compressor wheel housing 17 and of the housing 6 of the electric compressor 1 is furthermore visible.

(33) According to the present invention, the compressor wheel housing 17 can also be formed integrally with the housing 6 of the electric compressor 1.

(34) The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

LIST OF REFERENCE SIGNS

(35) 1. electric compressor 2. control unit 3. electric motor 4. compressor wheel 5. shaft 6. housing 7. cooling structure 8. cooling duct 9. stator 10. outer circumference (of the stator/stator carrier) 11. recess 12. moulding body 13. central axis of rotation 14. rotor 15. stator winding 16. connecting element 17. compressor wheel housing 18. first compressor wheel housing part 19. second compressor wheel housing part 20. circuit board 21. electronic modules 22. capacitors 23. plug connector 24. stator segment 25. stator carrier 26. projection 27. opening 28. cooling duct passage 29. opening moulding body 30. compressor gas inlet 31. compressor gas outlet 32. cooling fluid inlet 33. cooling fluid outlet 34. rear side (of the control unit)