CN104662781B

CN104662781B - Device and housing with cooling jacket

Info

Publication number: CN104662781B
Application number: CN201380043808.1A
Authority: CN
Inventors: H.韦尔-布鲁恩; G.阿龙佐; M.蓬特
Original assignee: Volkswagen AG
Current assignee: Volkswagen AG
Priority date: 2012-08-16
Filing date: 2013-08-05
Publication date: 2020-03-20
Anticipated expiration: 2033-08-05
Also published as: DE102012016208A1; WO2014026874A2; EP2885857A2; CN104662781A; WO2014026874A3

Abstract

The invention relates to a housing (1) with a cooling jacket for a device, in particular for an electric motor, comprising an inner part with a pipe section and an outer part (3) for receiving the pipe section, wherein the pipe section is rotationally symmetrical. The invention also relates to an electric motor having such a housing (1), wherein a cover (23) on an opening (17) of the housing (1) is fixed in a fluid-tight manner between the cooling jacket and the environment. At least one device, such as an inlet connection (20) and/or an outlet connection (21) and/or a partition (24) and/or a component to be cooled, is arranged on the cover (23).

Description

Device and housing with cooling jacket

Technical Field

The invention relates to a device, which can be formed by an electric motor, and to a housing for such a device with a cooling jacket.

Background

In devices with housing cooling, for example in electric motors, the device is enclosed in a two-part housing. The intermediate spaces formed between the housing parts, so-called cooling jackets, serve to receive and guide the coolant.

The development of motor cooling jackets, in particular for use as drive devices for electric vehicles, has placed special demands on researchers. The production of such a device is simple and can be carried out with little expenditure on material, machinery and time. The shaping of the cooling jacket in the devices known from the prior art always involves higher costs for processing tolerances.

In order to simplify the manufacture of two-part housings, attempts are made to use components or at least component sections having a simple geometry. For example, cylindrical cooling jackets with axially oriented cooling channels are known. A cooling jacket for cooling a stator of an electric motor is known from document US6,300,693B 1, which has two coaxial housings, cooling ribs between the housings, and end caps. The cooling ribs are arranged parallel to the central longitudinal axis of the cylindrical housing. The end cap is designed in such a way that a serpentine and/or serpentine through-flow of fluid is provided through the cooling channels which are separated from one another by the individual cooling ribs. Document US7,800,259B 2 shows a similar arrangement. Document WO 2006/106086 a1 also shows an electric motor with a cylindrical cooling jacket, through which a cooling jacket is passed in an axially meandering manner. Documents US6,727,611B 2, EP 1953897 a2 and US7,675,209B 2 show other devices of this type.

Document WO 2010/049204 a2 shows a cooling jacket with a coolant channel and an annular collector or distributor wound helically around the circumference of the cylinder and the axial length of the cooling jacket. The fitting on the coolant line is aligned tangentially with the cooling jacket. Document US 7591147B 2 also shows a cooling channel of helical shape, but in this device the collector and distributor and the joint are axially oriented. Document DE 102005058031 a1 discloses a single cooling jacket which is arranged helically around a central longitudinal axis between the motor housing and the outer housing and in which the inlet and outlet openings are radially aligned with the central longitudinal axis.

A disadvantage in these cooling jackets is that the surfaces, in particular the cooling channels, require mechanical reworking. This reprocessing can be very laborious. The casting skin is damaged in the cast part by reworking. Creating a smooth surface can adversely affect sealability and make it difficult to create turbulent flow. Mechanically reprocessed smooth surfaces have poorer heat transfer characteristics than the rougher casting skins compared to them. In addition, only complex geometries can be cast using sand cores. But the machining process is more elaborate when using sand cores. Some examples of this are, inter alia, the calculation of simulated closed cores, the pouring of sand cores, residual sand problems, the tooling of the mold used to create the sand cores, and the positioning of the sand cores in the mold over a large area.

Disclosure of Invention

Against this background, the object of the invention is to design a housing of the type described above with a cooling jacket such that the highest possible cooling efficiency is achieved with a low material outlay and at the same time the processing outlay is low.

This object is achieved by a two-part housing for an apparatus according to the invention with a cooling jacket.

According to the invention, a housing is provided, wherein the inner surface of the sleeve and/or the outer surface of the sleeve have a plurality of coaxially surrounding depressions and elevations. The formation of the coaxially encircling depressions and/or elevations makes it possible to maintain the rotational symmetry of the inner part, at least of its cylindrical pipe section, while at the same time the coolant is distributed uniformly over the circumference. The concavities and convexities have the function of guiding the coolant, and they also enlarge the surface that can achieve heat exchange with the coolant. In order to achieve a high cooling efficiency, the indentations and/or elevations are preferably provided on the inner surface of the jacket. The inventive method for producing rotationally symmetrical bodies with simple geometry allows casting methods to be produced which are cost-effective and largely eliminates the need for further processing. This reduces the processing costs. While enabling multiple installation conditions with consistent components. In comparison with the prior art, machining in the conventional casting process simultaneously achieves an efficient heat transfer, since the casting skin can be retained in the inventive molding without machining, which contributes to the formation of turbulent flows and to the enlargement of the effective surface by means of the concave and/or convex wave structure. No sand cores are required for the production of the inventive molding, which significantly reduces the outlay for calculations, molds and further processing, for example pouring.

The depressions and/or elevations are tangentially aligned with the pipe sections and/or the hollow space. Each depression and/or each elevation in this case spans a plane which is aligned parallel to the other planes of the other depressions and/or elevations. These planes are preferably aligned perpendicularly to the central longitudinal axis of the tube segment.

In order to receive and fix the stator of, for example, an internal rotor motor by means of a housing, the inner part comprises a bearing cap. The bearing cover also has a bearing for the motor rotor shaft in an embodiment variant. The bearing end cap is preferably connected to the pipe section in particular in one piece. The bearing end cap also has at least one plug receptacle. The plug receptacle can also be realized by a separate, not shown cover of the bearing end cap, which axially closes the bearing end cap. The bearing end caps are generally shaped in a rotationally asymmetrical manner. Machining the tube segments and the bearing caps in a single casting, either by casting the bearing caps onto the tube segments or by casting the tube segments onto the bearing caps, minimizes the chain of concentricity errors between the rotor and the stator, which advantageously affects the manufacturing process, the service life and the noise emission of the motor. If the pipe section is formed without a cast-in bearing end cap, it is also conceivable to mount it by bolting, pressing or welding.

The principle can be transferred to an electric motor with an outer rotor. In this case the function of the inner part and the outer part of the cooling jacket is reversed.

Advantageously, the depressions and/or elevations form channels for the coolant with the inner and outer jacket surfaces. For this purpose, the bead connected to the inner surface of the sleeve bears sealingly against the outer surface of the sleeve, or the bead connected to the outer surface of the sleeve bears sealingly against the inner surface of the sleeve. In a special embodiment, the inner and outer jacket surfaces have elevations which bear sealingly against the outer jacket surface in order to form fluidically separated channels. In this case, depending on the casting process, in particular, only the raised upper edge may have to be machined, so that it is not subject to large tolerances that are not allowed by the casting process. The surface directly adjacent to the coolant remains unmachined. Alternatively, embodiments are also conceivable in which a complete sealing of the channels against one another is dispensed with and the leakage rate between the channels can be allowed without the cooling effect of the housing being significantly altered.

Advantageously, the pipe section is rotationally symmetrical. The rotationally symmetrical shape of the pipe sections makes it possible to mass-produce the same inner part for different housing installation positions, in particular for different angular positions of the outer part of the plug receptacle. In this case, a uniform inner part, for example consisting of a pipe section and a bearing end cap, is installed in an adapted angular position of the plug receptacle as a transfer part (COP) in various environmental conditions. Preferably, the indentations and/or elevations annularly surround the inner surface of the sleeve.

It has proven particularly advantageous here if the outer part of the housing has at least one recess which is open to the hollow space. This recess serves as a collecting chamber for the coolant flowing through the cooling jacket. The outer part preferably has a plurality of such indentations. The collecting point of the cooling jacket is integrated into the outer part of the housing, so that the shape of the cooling structure, in particular the shape of the inner part, is not influenced, which improves the installation possibilities in the sense of a modular system. Consistent outer parts can also be manufactured in large quantities for different installation situations. Almost any number of different installation situations can be achieved by the housing according to the invention. The modular solution thus achieved enables the rotation of the stator and the outer casing or of the inner and outer parts of the outer casing. The opening of the hollow space for deflecting the coolant can be realized by arranging a partition plate inside the recess. In an embodiment of the invention, the separating plate is in particular integrally connected to the housing.

In one embodiment, the deflection of the partition plate is used at least at the cut-out, as a result of which the coolant is discharged from the intermediate space or is conveyed into the intermediate space. For this purpose, the outer part has openings in the region of the indentations. The housing exterior surface has one or more pipe connections for connection to coolant pipes. According to one embodiment, these joints are formed integrally with the outer part. Another configuration can be envisaged in which the coolant inflow and outflow is effected only through the collecting chamber, for example without a partition plate.

The development of the invention is characterized in that a receptacle for the apertured cover is provided on the edge of the recess. In a simple embodiment the cover is used to close the opening in a fluid-tight manner. The cover disposed on the outer surface of the housing may also be a stand for the device. The cover can, for example, comprise an inlet connection and/or an outlet connection for the coolant. In addition, a partition can be provided on the cover, as a result of which one or more arbitrary openings can be used for the supply and discharge of coolant, and according to the invention, independently of the position of the inner part relative to the outer part. The partition plate is arranged on the side of the cover pertaining to the intermediate space. In order to realize such a modular system also for the supply and discharge, the geometry of the receptacle for the cover is identical in all recesses or openings of the outer part according to one embodiment. The cover can also be produced in one piece with at least one inlet connection and/or at least one outlet connection in the casting mold.

The coolant discharge and supply can be effected via a single or a plurality of openings. In this case, it is possible to use an opening for the supply and a further opening for the discharge, or else a plurality of openings for the supply and simultaneously for the discharge of the coolant. The openings are preferably radially aligned with the central longitudinal axis of the pipe section or perpendicular to the jacket outer surface. Axial feed or discharge or other locations on the collection site are also contemplated. In order to provide sufficient space for the opening and/or at least for the receiving body of the cover and the cover to have an elongated, in particular rectangular shape, the latter has two long sides and two narrow sides. In order to avoid stress peaks, rounded corners or narrow sides are curved, for example consisting of a semicircle. It has proven advantageous if the two long sides are parallel to the central longitudinal axis of the tube section.

The invention relates to a cover, wherein a device is a structural component to be cooled. This component, for example a power circuit, is arranged on a side face which is attached to the outer side of the cover housing and is connected to the cover. In this case, the structural component can be flowed through with a coolant for its cooling or heating, which coolant flows in front of and/or behind the housing cooling jacket and/or parallel thereto. In the case of a cover structure with a structural component to be thermostated, coolant is removed from the hollow space through the opening, is guided through the structural component and is returned to the interior of the hollow space through the same opening. In a further embodiment, the fresh coolant is conducted through the inlet opening into the hollow space and, after the cooling jacket has been flowed through, is discharged from the hollow space through the same opening and then flows through the structural component arranged on the cover before being returned to the cold source through the outlet opening. The invention also includes the reverse situation, with the coolant flowing through the inlet, the structural component, the hollow space and then through the outlet. The cover can also accommodate a structural component which is not flowed through by coolant, but rather cooled by the heating line of the cover.

In an embodiment of the separating plate, this separating plate consists of a core of solid, rigid material, for example the material of the outer part or the cover. This core is preferably made integrally with the outer part or cap. At least one flange-shaped soft, elastic material is fixed on the core. The flange bears against the inner surface of the sleeve. According to a further development, the front edge of the flange has a design. The shaping of the flange leading edge to form the structure serves to improve the tightness of the flange-sleeve inner surface fit or to achieve a desired leakage rate. In order to achieve a very high seal, the structure is formed complementary to the inner surface of the sleeve, in particular in the inner surface of the sleeve, which is structured by means of depressions and/or elevations. To minimize the leakage rate, a plurality of flanges are provided on the plate-shaped core, preferably radially aligned with the central longitudinal axis. The flange is fixed to the core by means of a connecting means, for example, adhesive, vulcanization, injection or form-locking plug-in connection. The partition plate, in particular the flange, fits exactly or with a slight oversize for optimum sealing on the coolant channel structure and the opening side. The design of the partition plate allows the elimination of separate sealing measures between the inlet chamber and the outlet chamber and the multiple mounting and dismounting of the functional device without the need to replace the sealing measures. The coolant leakage rate between the inlet and the outlet of the hollow space can alternatively be adjusted directly by the shaping of the flange.

The invention comprises a cover which is fastened to the outer part in a fluid-tight manner closing the opening. In a preferred embodiment, a connection for a coolant hose is provided on the cover on one side and a partition is provided on the other side, orthogonally to the cover. The partition plate, which is oriented perpendicularly to the cover, not only allows a uniform volume division in the opening, but also a variable shaping of the outlet chamber and the inlet chamber. The cover is also easily assembled. The partition plate is embedded inside the cooling passage structure in a shape corresponding to the flange shaped of the cooling passage structure, and thus separates the coolant inlet from the coolant outlet. The pipe connection integrated into the cover allows a direct feed of the coolant pipe without further components.

The installation of the same inner part as the stator carrier in different installation spaces in the changing inlet connection and outlet connection solves the previously proposed problem. By virtue of the simplicity of construction, a multiplicity of functionalities and positioning can be achieved in a modular fashion. The same stator carrier can thus be combined as a module into different housing outer parts. The positioning of the collecting chamber formed by the recess in the outer part of the housing makes it possible to achieve different installation situations by means of a varying positioning and configuration of the cover and of the inlet position.

Drawings

The invention allows a large number of embodiments. One of which is illustrated in the accompanying drawings and described below to further illustrate the principles thereof. This embodiment shows:

FIG. 1 is a schematic view of components within a housing for an electric motor;

FIG. 2 is a schematic cross-sectional view of the inner parts and the stator and rotor of the motor;

FIG. 3 is a schematic view of an outer housing component of the motor;

FIG. 4 is a schematic cross-sectional view of the outer shell and the inner and outer members;

FIG. 5 is a schematic cross-sectional view of a first embodiment of the outer shell and outer member;

FIG. 6 is a schematic cross-sectional view of a second embodiment of the outer shell and outer member;

FIG. 7 is a schematic view of a third embodiment of the outer component;

FIG. 8 is a schematic perspective view of the first embodiment of the cover with the divider plate, inlet and outlet;

FIG. 9 is another schematic perspective view of the cover shown in FIG. 8;

FIG. 10 is a view of the inside of the cap shown in FIG. 8;

FIG. 11 is a view of the cover outboard side of the cover shown in FIG. 8;

FIG. 12 is a schematic cross-sectional view of the lid shown in FIG. 8;

FIG. 13 is a schematic perspective view of a second embodiment of the cover and structural assembly;

FIG. 14 is an inside elevational view of the cap illustrated in FIG. 13;

fig. 15 is an exploded view of the lid shown in fig. 13.

Detailed Description

Fig. 1 to 4 show a housing 1 for an electric motor, which is composed of an inner part 2 shown in fig. 1 and 2 and an outer part 3 shown in fig. 3. Fig. 4 shows the outer shell 1 with the inner part 2 and the outer part 3. The housing 1 has a cooling jacket in which a coolant circulates and which receives and discharges heat from the electric motor. The housing according to the invention can also be used for other heat sources or coolers to be cooled. The housing 1 according to the invention is described by way of example with the application of an electric motor. The motor comprises a stator 4 and a rotor 5. The rotor 5 is connected to a shaft 6, which is fixed in a rotationally movable manner in the housing 1 by means of bearings 7. The housing 1 consists of an inner part 2 and an outer part 3, which guide a coolant.

Fig. 1, 2 and 4 show an inner part 2 comprising a bearing end cap 8 and a tube section 9 having a tube inner surface 10 and a sleeve inner surface 11. The pipe section 9, in particular the jacket inner surface 11, is formed rotationally symmetrically according to the invention. At least one bearing 7 and at least one plug receptacle 12 are attached to the bearing shield 8. The embodiment of the inner part 2 shown in fig. 1 has a sleeve inner surface 11 with a plurality of coaxially surrounding depressions 37 and elevations 38. The depressions 37 and/or elevations 38 surround the jacket inner surface 11 in an annular manner and form channels for the coolant via the jacket inner surface 11 and the jacket outer surface 15 shown in particular in fig. 3,4 and 7. In the embodiment variant of the inner part 2 shown in fig. 2, the sleeve inner surface 11 is formed smoothly, in particular without elevations or depressions, and a single wide channel for the coolant is formed by the sleeve outer surface 15.

The outer part 3 shown in fig. 3,4 and 7 has a cylindrical hollow space 13 for receiving the pipe section 9. The outer part 3 has a housing outer surface 14 and a cylindrical circumferential sleeve outer surface 15 forming a hollow space. The outer part 3 also has indentations 16 on the sleeve outer surface 15. The outer part 3 has openings 17 in the region of the indentations 16. On the outer housing surface 14, at the edge of the opening 17, there is provided a receptacle 18 for a cover 23 shown in fig. 8 to 12 and a cover 31 shown in fig. 3 to 15 in a second exemplary embodiment.

Fig. 5,6 and 7 show three different embodiments of the outer part 3. Fig. 5 and 6 show how the inner part 2 is arranged concentrically inside the outer part 3, an intermediate space 19 being formed between the sleeve inner surface 11 and the sleeve outer surface 15. The intermediate space 19 serves for receiving a coolant and is also referred to as a cooling jacket. The outer part 3 and the inner part 2 are detachably connected without relative movement to each other.

Fig. 5 shows a first embodiment of the outer part 3. In this embodiment variant, the outer part 3 has two recesses 16, each of which has an opening 17 in the outer part 3. The indentations 16 in the outer surface 15 of the sleeve have a larger tangential cross-section than the openings 17 in the outer surface 14 of the housing. The openings 17 terminate on the housing outer surface 14 at an inlet connection 20 and an outlet connection 21 for the coolant. The inlet connection 20 and the outlet connection 21 are cast integrally with the outer part 3. The recess 16 facing the inner part 2 serves as a collecting chamber for the coolant flowing in the cooling jacket. The flow direction 22 of the coolant is indicated by an arrow. In this embodiment variant, the coolant flows through the cooling jacket around half of the circumference in two separate flows.

Fig. 6 shows a second embodiment of the outer part 3. In this exemplary embodiment, the outer part 3 has three recesses 16, each of which has an opening 17 in the outer part 3. On the outer housing surface 14, a receptacle 18 for a cover 23 shown in fig. 7 to 14 is provided on each opening 17. The shape of the cover 23 fixed to each receptacle 18 determines, for example, the divergence of the openings 17 as inlet and/or outlet.

Fig. 7 shows a third embodiment of the outer part 3. In this embodiment the outer part 3 has a recess 16 with an opening 17 of the outer part 3. The cover 23 shown here has the inlet connection 20 and the outlet connection 21 on a cover outer side 26 which is attached to the outer housing surface 26. The inner cover 23 of the inlet connection 20 and the outlet connection 21 has openings 31 shown in fig. 10 and 11. The cover 23 has a partition 24 on a cover inner side 25 attached to the cover outer surface 15. A partition plate 24 is arranged between the inlet connection 20 and the outlet connection 21, so that the coolant flows through the cooling jacket in this exemplary embodiment while flowing around the entire circumference. If the inner part 2 is arranged in the hollow space 13 of the outer part 3, the partition 24 bears in a fluid-tight manner against the inner jacket surface 11.

Fig. 8 to 12 show a first embodiment of the cover 23. As already described in fig. 7, the cover 23 has the inlet connection 20, the outlet connection 21 and the partition 24. Fig. 8 and 9 show perspective views of the cover. Fig. 10 shows a view of the inner cover side 25, and fig. 11 shows a view of the outer cover side 26. Separator plate 24 is comprised of a core 27 of a solid, rigid material. In the embodiment shown the core 27 is made in one piece with the cover 23. Two flanges 28 are provided on the core 27. The flange 28 is composed of a softer, resilient material than the core 27. The flange 28 is over-dimensioned so that it bears fluid-tightly against the inner surface 11 of the sleeve. The front flange edge 29 is formed by a contour, which is shaped in opposition to the geometry of the inner jacket surface 11. The flange 28 is fixed on the core 27 by vulcanization or injection. The cover 23 also has fastening means 30, which are formed in a manner that cooperates with the receiving body 18 shown in fig. 3,6 and 7. This enables a cover 23 to be provided on each arbitrary containing body 18. Fig. 10 and 11 show the channel 31 inside the inlet connection 20 and the outlet connection 21. The cover 23 of this first embodiment can be used to feed coolant to the cooling jacket and discharge it. Fig. 12 shows the cover 23 arranged on the housing 1, wherein the arrangement of the flange front edge 29 opposite the sleeve inner surface 11 is shown.

Fig. 13,14 and 15 show a second embodiment of the lid 32. A structural component 33, in particular a power circuit for an electric motor, is fastened to the cover outer side 26. The elements of the structural assembly 33 are arranged on a support plate 35. The cover 32 has fastening means 30 for connecting to the receiving body shown in fig. 3,6 and 7, and also connecting means 34 for fastening a structural component 33 or a support plate 35 to the cover 32. Heat transfer to the structural component 33 is effected via the cover 32 and the support plate 35. The support plate 35 has an annular projection 36 on the side facing the cover 32. The projection 36 sealingly bears against the lid outer surface 26, whereby the outwardly closed space is limited by the projection 36, the support plate 35 and the lid outer surface 26. The cover 32 has two channels 31. The channel 31 opens into this space on the cover outer side 26. On the cover inner side 25, separating plates 24 are arranged between the channels 31, as described in fig. 7 to 12. The coolant is guided from the cooling jacket to the space through the passage 31 by the partition plate 24. There, heat transfer between the coolant and the support plate 35 and thus the structural component 33 takes place before the coolant flows back into the cooling jacket of the housing 1 through the further channel 31 and is guided by the partition plate 24.

List of reference numerals

1 outer cover

2 inner part

3 outer part

4 stator

5 rotor

6 shaft

7 bearing

8 bearing end cover

9 pipe section

10 inner surface of tube

11 inner surface of the sleeve

12 plug holder

13 hollow space

14 outer surface of the housing

15 set of outer surface

16 notches

17 open pore

18 (for lids) containing body

19 intermediate space

20 input connector

21 discharge joint

22 direction of flow

23 cover (variant 1)

24 division plate

25 inner side of the cap

26 cover outer side

27 core (splitter plate)

28 Flange

29 front end edge of flange

30 fixing device

31 channel

32 cover (variant 2)

33 structural component

34 measures for connection

35 support plate

36 convex

37 is concave

38 bump

Claims

1. Housing (1) with a cooling jacket for a device, comprising an inner part (2) with a tube section (9) having a circular cross section, a tube inner surface (10) and a sleeve inner surface (11), and an outer part (3) with a hollow space (13) for accommodating the tube section (9), a jacket outer surface (15) and a housing outer surface (14), wherein an intermediate space (19) for accommodating a coolant is formed between the sleeve inner surface (11) and the jacket outer surface (15), wherein the tube section (9) is rotationally symmetrical, characterized in that the outer part (3) has two recesses (16) facing the hollow space (13) as collecting chambers for the cooling jacket, and the sleeve inner surface (11) and/or the jacket outer surface (15) has a plurality of coaxially encircling recesses (37) and elevations (38) annularly surrounding the sleeve inner surface (11), so that the coolant is distributed uniformly over the circumference, wherein each concavity and/or each convexity spans a plane, oriented parallel to the other planes of the further recesses and/or elevations, perpendicular to the central longitudinal axis of the pipe section (9), and the depressions (37) and/or elevations (38) form channels for a coolant with the jacket inner surface (11) and the jacket outer surface (15), and wherein the outer part (3) has an opening (17) in the region of the recess (16), which terminates on the outer housing surface (14) in an inlet connection (20) and an outlet connection (21) for the coolant, so that the coolant flows through the cooling jacket in two separate flows around each half of the circumference, wherein the respective opening (17) extends in the axial direction over the entire intermediate space (19).

2. Housing (1) according to claim 1, characterized in that said device is an electric motor.

3. Housing (1) according to claim 1, characterised in that a partition (24) is provided in the recess (16) for dividing or guiding the coolant flow.

4. The outer casing (1) according to any one of claims 1 to 3, characterized in that the inner part (2) comprises a bearing end cap (8).

5. Housing (1) according to claim 4, wherein the bearing end cap (8) is integrally connected with the tube section (9).

6. Housing (1) according to any one of claims 1 to 3, characterized in that a receiving body (18) for a cover (23, 32) is provided on the edge of the opening (17).

7. Housing (1) according to claim 6, characterized in that a receiving body (18) for the cover (23, 32) is provided on the housing outer surface (14).

8. Housing (1) according to any one of claims 1-3, characterized in that the depressions (37) and/or elevations (38) are aligned tangentially to the tube section (9) and/or the hollow space (13).

9. An electric motor having a housing (1) according to any one of claims 1-8.

10. An electric motor as claimed in claim 9, characterized in that at least one means is provided between the cooling jacket and the surroundings on the cover (23, 32) for the opening (17) of the housing (1).

11. Electric motor according to claim 10, characterised in that said means are the inlet connection (20) and/or the outlet connection (21) and/or the partition (24) and/or the structural component (33) to be cooled.