WO2004036720A1

WO2004036720A1 - Cooling case jacket for electrical machines

Info

Publication number: WO2004036720A1
Application number: PCT/EP2003/011591
Authority: WO
Inventors: Hans-Jürgen Wehner; Günter Sonnauer
Original assignee: Baumüller Nürnberg GmbH
Priority date: 2002-10-18
Filing date: 2003-10-20
Publication date: 2004-04-29
Also published as: DE20216112U1; AU2003276122A1

Abstract

The invention concerns a cooling case jacket capable of being cooled, designed for an electrical machine and produced as a cast part. In order to house an inner rotor/concentric stator assembly additionally to the windings and coil heads, the inventive case jacket is produced according to a design symmetrical, concentric or coaxial relative to a predetermined machine axis of rotation and is traversed by one or more cooling channels circulating the cooling medium. The cooling channel(s) are terminated on at least one first surface among several surfaces of the case jacket by apertures freely accessible outwards. On a second of the surfaces of the case jacket, the cooling channels are terminated at a case wall formed by casting and are hence tightly closed with respect to outside air.

Description

Cooling jacket for electrical machines

The invention relates to a coolable housing jacket for an electrical machine, which is present as a molded part produced by casting. To accommodate a coaxial or concentric inner rotor / stator arrangement including windings and winding heads, the housing jacket is designed with a concentric and / or coaxial feedthrough that is symmetrical with respect to an imaginary machine axis of rotation. The cooling is implemented by means of a circulation of cooling medium through one or more cooling channels which penetrate the housing jacket. The one or more cooling channels end on at least a first side of the housing shell with openings that are freely accessible to the outside. The invention further relates to a housing for an electrical machine, which has the housing shell mentioned.

With regard to the prior art, reference is first made to DE 42 29 395 C2, DE 199 49 140 A1, DE 199 39 013 A1, DE 196 24 519 A1, DE 39 41 474 A1 and US 50 84 642 A.

A stator housing for a liquid-cooled internal rotor motor is known from DE 196 51 959 A1. A helical cooling tube coil is cast into a housing jacket which comprises a stator core. However, nothing can be found about the location in the motor housing where the cooling pipe coil has its ends. According to DE 196 27 029 A1, the cast-in cooling pipe coil has projecting connection ends on one end face. In the area of an end face of the stator housing, connecting tubes extending from one corner area to the other corner area are arranged, which lie axially in front of the stator core. Via these connecting pipes, the pipe sections located in one corner area are connected to the pipe sections of the other corner area in such a way that the cooling pipe coils have a meandering shape overall. However, no details can be taken about the front cover of the stator housing.

In contrast, DE 197 57 605 A1 shows bearing shields with an electric motor with cooling, which have openings for axially parallel projecting end pieces are provided by cooling channels. Pipe-like deflection elements are welded or glued to it to deflect the cooling flow. These penetrate the peripheral areas of the end shields.

DE 100 05 128 A1 describes a coolable stand for an electrical machine. The stator core is interspersed with cooling tubes, each of which ends freely on the end faces of the stator core. In order to be able to redirect the cooling flow there, end shields which can be attached are designed with deflection chambers in their interior.

A generic electric motor with liquid cooling is described in DE 100 45 424. A housing jacket is hollow and divided into several channels through which cooling medium flows. On both sides of the electric motor there is a connection channel for the supply of the cooling liquid from the housing jacket into the end shield in the associated end shield. The inside of the end shield is completely filled with cooling liquid so that the bearings and couplings for pumps to be driven are cooled and lubricated at the same time. The end shields are made separately from the housing shell as individual castings.

In contrast, the task is raised according to the invention to increase the service life and reliability of the seals in electrical machines with a cooled housing jacket and cooling channels ending on the housing sides. According to the invention, the coolable housing jacket specified in protection claim 1 is proposed as a solution. Advantageous or expedient details and refinements of the invention result from the dependent claims.

It is thus left the path that has been used in the prior art to cover the parallel end faces of an electrical machine cooled by a housing jacket by a bearing plate each formed as a separate piece. Rather, it is proposed according to the invention to cast a housing shell side or end face with the cooling channels that open there, which is efficient in terms of production technology together with the casting of the cooling housing shell in one Can be done together. In the course of this common work step, a “bearing plate” or “pressure ring” is cast on to the casing shell, which is designed in one piece with the other casing shell. The need to seal the joints created in the prior art due to the butting of separate bearing plates with the front side of the housing body by welding, gluing or the like is thus eliminated with the proposal according to the invention. At the same time, a considerable advantage in terms of production and assembly is achieved in a simple manner: namely, a separate, time-consuming and thus labor-intensive installation of at least one of the end shields can be omitted. In addition to improving the seal, the invention can thus surprisingly achieve a simultaneous reduction in production costs.

To facilitate the coolant circulation, including on the front or other end sides of the engine cooling jacket, it is proposed according to a special embodiment of the invention to design the second housing end wall formed by casting with cavities in its interior so that these with the cooling channels to be able to communicate. These cavities can then be used as deflection chambers (see, for example, DE 100 05 128 A1 mentioned above) or coolant cross bushings which run transversely with respect to an imaginary machine axis of rotation and connect the channel ends and / or deflection chambers to one another.

For the one-piece production of the casing shell with cast-on bearing plate or pressure ring according to the invention, mold cores must be used, by means of which the cooling channel system is molded in the interior of the casing shell. In order to be able to hold and fix them and, if necessary, to release them again, according to a further advantageous embodiment, it is provided to provide the integrally molded housing shell side in its cast wall with one or more bores or other openings. Are particularly useful

Internally threaded bores, in which then opposite for sealing screwing elements that seal the inside of the coolant while the engine is running can be screwed in.

In order to further increase the corrosion resistance, service life and reliability of the coolant flow circuit and the entire cooling system of the electrical machine, a particularly advantageous embodiment of the invention consists in immersing at least the inner surfaces of the housing shell and in particular the surfaces of the inner walls of the cooling channels incorporated therein by means of an immersion process. in particular to coat a cathodic dip coating process or a cathophoresis coating. Such methods are known per se from the motor vehicle industry. Such an electrocoat, which is deposited cathophoretically on the housing jacket, is expediently based on epoxy-amine-urethane. The cast housing shell, which is preferably made of aluminum, represents the negatively polarized cathode during the electrolytic coating process. The desired layer thickness, expediently between 10 μm and 50 μm, is set here via the level of the immersion bath voltage and the time within which this voltage is present. When this design is combined with the previously mentioned bores or openings, there is the special effect that the immersion bath liquid can easily escape from the interior of the housing via the bores or openings.

Within the scope of the general inventive idea is also a coolable (overall) housing for an electrical machine with the housing jacket according to the invention and the features otherwise specified in the independent protection claim 14. Thereafter, a separately manufactured cover device is fixed to the first (not cast) side of the housing shell, which is alternatively or cumulatively provided with an inlet and / or outlet, with deflection chambers and / or with transverse bushings for guiding the cooling medium, with respect to an imaginary machine axis of rotation run across. The transverse bushings serve to connect the ends of the cooling channels and / or the deflection chambers connected to one another.

With this housing structure according to the invention (first jacket side with cooling channel ends left open, second jacket side with cast-in Cooling channel ends) takes into account the casting need for mold cores, which fill the internal cavities in the course of casting the housing jacket body, in particular for the cooling channels, and must be removed or pulled out of them again after the casting process has ended. In the cooling housing structure according to the invention, this can be done by the first jacket side, which is still left open.

For reliable sealing of the flow circuit for coolants in the machine housing, one or more sealants are expediently arranged between the cover device and the first (left open) side of the housing shell. The sealants are expediently located in the region of one or more cooling channel ends, associated deflection chambers and / or transverse bushings and serve to limit and seal them.

Such a sandwich-like structure can advantageously be further developed by designing the sealing means as flat sealing bodies. Complementary to this, recesses are made in one or both opposite walls of the cover device and / or the first side of the housing shell, in which the flat sealing bodies can be accommodated. In particular with suitable dimensioning of the thicknesses and elasticity / compressibility of these sealing bodies, it is then possible that the first side of the housing shell and the opposite cover device can be arranged with their walls directly adjacent to one another or also pressed together. This advantageously allows simple and large-area insulation or sealing of the cooling channel ends, if appropriate with deflection chambers and transverse bushings, in particular in the area of the end shield. If, in addition, the cover device is screwed firmly, in particular axially parallel, to the housing shell (end face), its metal, in particular aluminum walls can lie flat against one another and in a highly durable manner. The sandwich-like, flat sealing bodies no longer need to be pressed too hard or compressed at all and are thereby mechanically stressed, as a result of which they are subject to material fatigue over time and would therefore become leaky. With particular advantage, the dt bodies and the complementary depressions are arranged only in areas where the cooling medium flows, in particular, transversely to the machine axis of rotation. By simply and quickly inserting the flat sealing bodies into the complementarily shaped recesses, a positive connection can be achieved in a short time, which means that the sealing bodies can be held precisely without (too strong) mechanical impairment due to compression. The advantage of the simplicity and speed of assembly is obvious. In addition, the strength of the cohesion of the cover device and the housing shell side is promoted by the abovementioned, direct abutting of the metal wall on both sides.

Further details, features and advantages on the basis of the invention result from the following description of preferred embodiments of the invention and from the drawings. These show in:

FIG. 1 shows a perspective illustration of an exemplary cooling

Casing according to the invention,

2 shows a perspective view of the end face of the housing shell according to FIG. 1 cast on according to the invention, which is supplemented by screwing on the cover device on the other end face to form the overall cooling housing,

3 shows the overall housing according to FIG. 2 in a perspective view of the end face provided with a separate covering device, FIG.

FIG. 4 shows an axial sectional view of an arrangement of the cooling housing according to the invention with a stand for an electrical machine accommodated therein,

5 shows the arrangement in plan view in the direction V in FIG. 4,

FIG. 6 shows an end view in the direction VI in FIG. 4, FIG. 7 shows an end view in the direction VII in FIG. 4,

FIG. 8 shows the pressure ring serving as a covering device without a stator and without

Stator windings in radial side view,

FIG. 9 shows an end view in the direction IX in FIG. 8,

FIG. 10 shows an end view in the direction X in FIG. 8,

Figure 11 is a plan view in the direction XI in Figure 9, and

Figure 12 is a perspective view of an enlarged, broken-away section of the area with

Sealing device between the housing jacket end face and the opposite end face of the cover device or the pressure ring.

According to Figure 1, the housing shell 1 is made as a one-piece aluminum casting with a total of eight axially parallel cooling channels 2. The housing jacket 1 has a clear passage 3 in its interior, which is symmetrical with respect to an imaginary machine axis of rotation and serves to accommodate a coaxial or concentric inner rotor / stator arrangement together with windings and winding heads (as also shown in FIG. 4). The cooling channels 2 run parallel to the imaginary axis of rotation of the machine (parallel to the axis) between a recess contour 3a which borders the bushing 3 and the axially parallel outer wall 4 of the housing shell 1. Two cooling channels 2 are arranged next to one another per circular quadrant. Their ends are left open on a first housing jacket end face 5a of two parallel end faces 5a, 5b or are freely accessible. As can also be seen from FIG. 2, the cooling channels 2 end at the second end face 5b on a respective cast wall 6 or are cast there. As a result, there is no leakage of cooling medium or cooling liquid via the second end face 5b possible. Cooling medium can be supplied to the end of a first cooling duct 2a in the region of the second end face 5b, via an inlet opening 7, which has a deflection chamber, optionally with a deflection chamber, on a longitudinal upper side 8 and there in a corner region adjacent to the second end face 5b as a transverse to the axis-parallel direction is designed for a 90 ° flow deflection 10. Correspondingly, on the longitudinal top 8 in the opposite corner region, an outlet opening 11 is also formed on the second end 5b, which communicates via a 90 ° flow deflection 10 with the last cooling channel 2h ending in the region of the second end 5b. Corresponding to the inlet channel 9 at the inlet opening 7, the outlet opening 11 has an outlet channel 12 which also penetrates the longitudinal top 8 and which runs transversely to the axis-parallel direction.

To form the closed cooling circuit, 180 ° flow deflections 13 must take place on the first end face 5a between the ends of two adjacent cooling channels 2a or 2b, 2c or 2d, 2e or 2f, 2g or 2h which are open there. A 90 ° flow deflection 10 thus alternates on the opposite, second end face 5b within the cast wall 6 cast on there (for the sake of clarity, only shown in the areas of the inlet / outlet openings 7, 11). Between the 90 ° flow deflections (not shown), which do not take place in the area of an inlet / outlet opening 7, 11, transverse bushings 14 each run at right angles to the cooling channels within the cast wall. The 90 ° flow deflections 10 still taking place after the inlet 11 each open into one of the crossings. Cooling medium flowing from one circular circumference quadrant to the respectively adjacent one can thus be conveyed within the cast wall 6 of the second end face 5b. Each transverse bushing 14 connects the end of a cooling duct 2 located in the second end face 5b to the cooling duct end of an adjacent circular circumference quadrant likewise located in the second end face 5b.

According to FIGS. 1 and 2, assembly and drain bores 15, which are aligned on the end face, are formed on the second end face 5b, each with one of the Cooling ducts 2b-2g or their ends and the transverse passages 14 communicating therewith are connected (except for the first and last cooling ducts 2a and 2h in the flow circuit) and penetrate the cast wall 6 leading outwards. They are expediently provided with an internal thread in order to be able to fix holding elements for casting mold cores in the cavities of the housing shell during the manufacturing and casting process. In addition, the liquid of an immersion lacquer bath can run out through the bores 15 if the housing jacket is subjected to immersion lacquer processes, in particular for its cavity surfaces, for corrosion-resistant coating (see above). The (not shown) internal threads of the bores 15 can also be used to receive and fix sealing screws 16 (see FIG. 6) provided with sealing rings, in order to seal the circulation of the cooling medium from the external environment in practical engine operation, for example. The first and last cooling channels 2a and 2h, on the other hand, are not connected to assembly and drain bores, but, as stated, to the inlets and outlets 7, 11, through which immersion lacquer bath liquid can also run off after the casting process.

According to FIG. 3, the openings of the cooling channels 2 located on the first end face 5a are separated by a separately produced pressure ring 17 (cf. also FIGS.

11) closed to the outside. This is by means of an imaginary one

Rotating axis rotating row of fixing screws 18 on the adjacent

End wall of the housing shell 1 attached. An axially parallel

Side wall 19 of the housing shell 1 is designed on the first end face 5a with an elongated rectangular recess 20 which, together with the opposing pressure ring 17, delimits a free opening 21 which the

Implementation of cable connections for the windings or the like can serve. Of course, these must be compared to the flow circuit of the

Coolant be sealed. For this purpose, flat sealing bodies 22 (see also FIG. 12 and associated explanations) are arranged in a sandwich-like manner between the opposite end walls of the pressure ring 17 and the housing shell 1. FIG. 4 shows that the housing jacket 1, together with the pressure ring 17 attached to it, coaxially comprises a stator core 23 or the associated winding heads 24. Details essential to the invention are readily apparent to the practiced reader of technical drawings from FIGS. 4-7 without further explanation, especially since the same reference numbers denote the same parts.

From FIGS. 8-11, which represent the pressure ring 17, FIG. 9 shows that pressure ring end face which, according to FIGS. 1-3, faces away from the housing jacket, while, conversely, FIG. 10 shows that end face which, in the assembled state, on the opposite end wall or first end face 5a of the housing jacket. According to FIG. 11, fastening bores 25 are formed on the upper side of the outer surface of the pressure ring 17, via which a terminal box or the like can be mounted.

According to FIG. 12, the housing jacket 1 is designed on the first end face on its wall opposite the pressure ring 17 with a receiving recess 26 or recess, for example milled in. The depth is dimensioned such that the flat sealing body 22 with a corresponding thickness 29 can be accommodated therein. The latter serves to seal the ends of the two cooling channels 2g, 2h and the 180 ° flow deflection 13 connecting the two in a deflection chamber 29 from the other surroundings. The flat sealing body 22 forms a sealing wall 22 for the deflection chamber 28 gh, as it were. It is within the scope of the invention to clamp the flat sealing body 22 somewhat or to compress it between the pressure ring 17 and the opposite end wall of the housing shell 1. For this purpose, the flat sealing bodies or sealing walls 22 extend beyond the deflection chamber 28gh into the peripheral area between the facing end walls of the pressure ring 17 and the housing shell 1. However, the compression need only be carried out relatively slightly because the butt joint immediately following the receiving recess 26 in the transverse direction 27 is formed by the abutment of the respective metallic wall surfaces of the pressure ring 17 and the housing shell 1. The fixing screws 18 can be used to seal the metal surfaces in the area of the butt joint 27 with high contact pressure, without the flat sealing bodies 22 being pressed together excessively and having to be mechanically impaired. Because they find enough space in the receiving recess 26. On the other hand, the screwing of the pressure ring 17 to the opposite wall of the housing casing 1 creates "block-on-block" strength and stability. It can be deduced from FIGS. 2, 3, 5 and 12 that in the example shown, four receiving recesses 26, each of which detects a sealing wall 22, alternate with four butt joints 27 in the context of a row surrounding the imaginary axis of rotation of the machine, it can also be seen in FIG Deflection chamber 28gh ends, which is delimited and sealed by the flat sealing body 22.

LIST OF REFERENCE NUMBERS

1 housing jacket

2, 2a-2h cooling channels

3 implementation

4 wall

5a first end face

5b second end face

6 cast end wall

2a first cooling channel

7 inlet opening

2h last cooling channel

8 longitudinal top

9 entry channel

10 90 ° flow deflection

11 outlet opening

12 execution channel

13 180 ° flow deflection

14 cross feedthrough

15 mounting and drain hole

16 screw plug pressure ring

fixing screws

long side

recess

opening

Flat sealing body or sealing wall

Stator core

winding

mounting hole

receiving recess

butt joint

deflection

thickness

Claims

claims

1. Coolable housing jacket (1) for an electrical machine, which is manufactured as a cast molded part, for receiving a concentric inner rotor / stator arrangement (23) together with windings (24) and winding heads with a concentric and symmetrical with respect to an imaginary machine axis of rotation / or coaxial feedthrough (3) designed and to form a circulation (2a-2b-2c-2d-2e-2f-2g-2h) of cooling medium is penetrated by one or more cooling channels (2), which is connected to at least a first (5a) of a plurality of housing shell sides (5a, 5b) end with openings freely accessible to the outside, characterized in that in a second (5b) of the housing shell sides (5a, 5b) the cooling channels (2) on a housing wall (6 ) end and are tightly sealed from the outside.

2. Housing jacket according to claim 1, characterized in that the housing jacket sides (5a, 5b) comprise two opposite and / or parallel end faces (5a, 5b), of which the first (5a)

Cooling channels end freely accessible to the outside, and in the second (5b) the cooling channels (2) end at a housing end wall (6) formed there by casting and are thus sealed off from the outside.

3. Housing jacket according to claim 2, characterized in that the second housing jacket side or end wall (6) formed by casting connects in one piece to the other housing jacket body (1).

4. Housing jacket according to claim 2 or 3, characterized in that the second housing end wall (6) formed by casting is provided in the interior with cavities such that these cavities with the cooling channels (2) communicating deflection chambers and / or transverse bushings (14) which, with regard to an imaginary machine The axis of rotation is transverse and connects the channel ends and / or the deflection chambers to one another.

5. Housing jacket according to claim 2, 3 or 4, characterized in that the second housing end wall (6) formed by casting a symmetrical with respect to an imaginary axis of rotation, concentric and / or coaxial bore or recess or other passage (3) for receiving of an internally rotating rotor and / or of stator core assemblies (23) together with winding heads (24).

6. Housing shell according to one of the preceding claims, characterized in that the housing shell side formed by casting and closing the cooling channels in its cast wall (6) has one or more bores (15) or other openings.

7. Housing jacket according to claim 6, characterized in that the bores (15) or openings have internal threads for the attachment of casting core holding elements and / or for receiving screw closures (16).

8. Housing jacket according to claim 7, characterized in that the screw caps (16) are provided with sealing rings.

9. Housing jacket according to claim 6, 7 or 8, characterized in that the bores or openings as inlets or outlets (7.1 1) for

Designed cooling medium and communicate with the cooling channels (2), optionally via a deflection chamber and / or transverse passage (14).

10. Housing jacket according to one of the preceding claims, characterized by a coating of the jacket inner surfaces including the channel inner walls via an immersion process, in particular a cathodic immersion process.

11. Housing jacket according to Ans ^ -uch 10, characterized by the fact that the coating thickness is between 10 μm and 50 μm.

12. Housing jacket according to claim 10 or 11, characterized by the use of a preferably cathaphoretically deposited

Dip coatings based on epoxy-amine-urethane.

13. Housing jacket according to one of the preceding claims, characterized by a production of the jacket body including the formed by casting and the cooling channels closing

Housing shell side (6) with aluminum, preferably by casting.

14. Coolable housing for an electrical machine, comprising a housing shell (1) according to one of the preceding claims, characterized in that on the first housing shell side (5a) of the

Housing casing (1) a separately manufactured cover device (17) is attached, which is provided for directing the cooling medium with an inlet and / or outlet, with deflection chambers (28) and / or transverse bushings which are transverse with respect to an imaginary machine axis of rotation run and with the ends of the cooling channels (2) or with the

Communicate deflection chambers (28).

15. Housing according to claim 14, characterized in that the cover device (17) as a bearing plate or pressure ring (17) with a symmetrical with respect to an imaginary machine axis of rotation, concentric and / or coaxial passage (3), hole or recess for receiving an inside rotating rotor and / or of stator core (23) together with winding heads (24).

16. Housing according to claim 14 or 15, characterized by one or more sealing means (22) which between the cover device (17) and the first casing side (5a) in the region of one or more cooling channel ends, associated deflection chambers (28gh) and / or transverse Bushings (14) are arranged to limit and seal them.

17. Housing according to claim 16, characterized in that the sealing means of the cover device (17) and the first housing shell side (5a) are held, embraced or clamped in a sandwich-like manner.

18. Housing according to claim 16 or 17, characterized in that the covering device (17) and / or the first housing shell side (5a) on its or its respective opposite walls with

Wells (26) are provided, and the sealing means (22) are formed as flat sealing bodies with a shape complementary to the wells (26) and are received in the wells (26).

19. Housing according to claim 18, characterized in that the thickness (29) of the sealing body (22) is dimensioned such that the first housing shell side (5a) and the opposite cover device (17) lie directly against one another.