RU2782235C1 - Encapsulated electric machine with liquid external cooling circuit - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: encapsulated electric machine with an air internal cooling circuit and a liquid external cooling circuit comprises a rotor (1) and a stator (2). The rotor (2) is configured to rotate around the axis (4) of rotation of the electric machine. When viewed around the axis (4) of rotation, the rotor (1) is surrounded by the stator (2), and the stator (2) is surrounded by an external shell (6) at a radial distance (a1). The radial distance (a1) varies. The external shell (6), when viewed in the direction of the axis (4) of rotation, extends, respectively, from the front end part (7) toward the back end part (8) so that the front and back end parts (7, 8) and the stator (2) define the inner area (9) containing the rotor (1). The front and back parts (7, 8), the stator (2), and the external shell (6) define the outer area (10) surrounding the inner area (9) radially on the outside. The inner area (9) and the outer area (10) are connected and communicated by means of recesses (11), so that the air (12) from the inner area (9) can flow to the outer area (10) and back into the inner area (9). Axially passing pipes (13) are secured in the front and back end parts (7, 8) so that each axially passing pipe (13) passes from the front end part (7) along the outer area (10) to the back end part (8). When viewed around the axis (4) of rotation, the axially passing pipes (13) are distributed around the axis (4) of rotation at an angle of more than 180°. A front and back protective elements (14, 18) are set liquid-impermeably on the front and back end parts (7, 8) on the corresponding side thereof facing away from the external shell (6), so that the front end part (7) and the front protective element (14) envelop the front hollow space (15), and the back end part (8) and the back protective element (18) envelop the back hollow space (19). The axially passing pipes (13) enter the front and back hollow spaces (15, 19). The front hollow space (15) has a connection (22) for the entry of liquid cooling medium (23). The front and back end parts (7,8) and the external shell (6) encapsulate the rotor (1) and stator (2) by the Ex d type of explosion protection.

EFFECT: increase in the efficiency of using the electric machine and improved cooling.

10 cl, 7 dwg

Description

This invention relates to an electrical machine,

- moreover, the electric machine has a rotor and a stator,

- moreover, the rotor is installed with the possibility of rotation around the axis of rotation of the electric machine,

- moreover, if you look around the axis of rotation, then this rotor is surrounded by a stator, and the stator is surrounded by an outer shell,

- moreover, this outer shell, when viewed in the direction of the axis of rotation, extends from the front end part to the rear end part, so that the front and rear end part and the stator define the inner region containing the rotor, and the front and rear end part, the stator and the outer shell define an outer region surrounding the inner region radially from the outside,

- wherein the inner region and the outer region are connected to each other by means of recesses, communicating with each other, so that air can flow from the inner region to the outer region, and from there again back to the inner region,

wherein the axially extending tubes are fixed in the front and rear ends, respectively, so that these axially extending tubes extend from the front end over the outer region to the rear end, respectively.

In some applications, the electrical machines used must be encapsulated (closed, hermetically sealed) according to the type of protection Ex d. However, this kind of electrical machines are also required in more and more constructive forms.

With large designs of such electrical machines, these electrical machines are often designed as described above. These electrical machines are air-cooled. To this end, a fan is installed on one of the two end faces, on the side facing away from the outer casing, by means of which cold air is blown through the axially extending pipes for secondary cooling.

Air is a relatively poor cooling medium. It would be better to cool the electrical machine in the context of secondary cooling with a liquid cooling medium, in particular water.

An electric machine of the kind mentioned at the outset is known, for example, from US 3 457 439 A or from CN 101 938 191 A. An electric machine of this kind is also disclosed in WO 2016/008 709 A1.

The object of the present invention is to provide an electrical machine of the kind indicated at the outset, which is cooled by a liquid cooling medium.

This problem is solved by means of an electric machine with features of the independent claim 1 of the claims. Preferred embodiments of the electrical machine are the subject of dependent claims 2-11.

According to the invention, an electric machine of the kind mentioned at the outset is characterized in that

- that front and rear protective elements are installed liquid-tight on the front and rear end parts on their side respectively facing away from the outer shell, so that the front end part and the front protective element surround the front hollow space, and the rear end part and the rear protective element surround posterior cavity,

- that the pipes extending axially open into the anterior and posterior hollow spaces,

- that the anterior hollow space is divided by a partition into at least two subregions,

- that part of the axially extending pipes exit in one of these sub-regions, and another part of the axial-flowing pipes exit in another of these sub-regions,

- that in one sub-area there is a connection (nipple) for supplying liquid refrigerant, and

- that the liquid coolant connection is located in a different sub-area.

Said at least two sub-regions are separated from each other by means of a partition in a fluid-tight manner. Said front hollow space is closed impermeable to liquid, except for the connections for inlet and outlet of liquid cooling medium, as well as for access to axially extending pipes. The rear hollow space is closed fluid-tight, with the exception of access to axially extending pipes.

Preferably, the front and rear ends and the outer shell encapsulate the rotor and stator in an Ex d type of protection. As a result, the electric machine can also be used in environments subject to explosion hazard.

The axially extending pipes have an inner diameter and an outer diameter. Preferably, the axially extending tubes are at a corresponding radial distance from the stator which is at least the same as the inner diameter, in particular even at least the same as the outer diameter. This simply creates an area in which a seal can be placed to seal both protective elements against the end portions.

It is possible that the axially extending pipes are designed as double-walled pipes, each having an inner pipe conducting liquid cooling medium and an outer pipe that surrounds this inner pipe, and the outer region of which flows around the air flowing from the inner region to the outer region. This embodiment, although relatively complex, has the advantage that a simple leak in one of the inner tubes cannot lead to accumulation of liquid in the inner region.

Alternatively, it is possible that the axially extending tubes are designed as single-walled tubes, which conduct the liquid cooling medium inside and the air that has escaped from the inner region into the outer region flows around them on the outside.

In both cases, it will be advantageous if a liquid detection device is provided in the inner region and/or in the outer region. As a result, the danger of a short circuit can be detected in good time before an electrical short circuit caused by the liquid coolant occurs and warned of this, respectively, it is even possible to switch off the electric machine automatically.

Preferably, the axially extending tubes, when viewed about the axis of rotation, are distributed around the axis of rotation at an angle greater than 180 ^° . As a result, efficient cooling can be achieved despite the relatively compact design. In other cases, this angle may not be reached.

Preferably, the stator is surrounded by an inner shell without a gap, and the inner shell is at a radial distance from the outer shell.

The above described features, features and advantages of the present invention, as well as the manner in which they are achieved, will become clearer and clearer from the following description of the exemplary embodiments, which are discussed in more detail in conjunction with the drawings. In this case, the drawings schematically show the following.

Fig. 1 longitudinal section of an electrical machine,

Fig. 2 is a section along the line II-II in FIG. one,

Fig. 3 fragment from Fig. one,

Fig. 4 separate pipe,

Fig. 5 separate pipe,

Fig. 6 section of the outer shell, and

Fig. 7 section of the inner shell.

According to FIG. 1, the electrical machine has a rotor 1 and a stator 2. The rotor 1 is mounted on a rotor shaft 3 which is rotatably mounted. This rotor shaft 3 and with it the rotor 1 can therefore rotate about the axis 4 of rotation of the electrical machine.

Whenever the terms "axial", "radial" and "tangential" are used in the following, they are always referred to with respect to the axis 4 of rotation. "Axial" is in a direction parallel to the axis 4 of rotation. "Radial" is a direction orthogonal to the rotation axis 4, directly onto, towards or away from the rotation axis 4 . "Tangential" is a direction that runs both orthogonal to the axial direction and orthogonal to the radial direction. Thus, "tangentially" is a direction which, at a constant axial position and at a constant radial distance from the axis of rotation 4, is circumferentially directed around the axis 4 of rotation.

Within the framework of the present invention, the stator 2 is positioned radially on the outside and the rotor 1 is positioned radially on the inside. Further, the stator 2, as shown in FIG. 1 is surrounded by an inner sheath 5 without a gap. However, this is not necessarily necessary. Alternatively, the stator 2 could be surrounded by only a few rings, with at least one ring located at both axial ends of the stator 2. However, the stator 2 is surrounded by an outer shell 6. The outer shell 6 is located at a radial distance a1 from the stator 2, respectively, in this case from the inner shell 5.

The outer shell 6 generally has a cylindrical shape. The same applies, as a rule, to the inner shell 5, if any. The said radial distance a1 is often constant when viewed in the tangential direction. However, both for the outer shell 6 and for the inner shell 5, if present, deviations from the cylindrical shape are possible. The radial distance a1 can also vary.

The outer shell 6 extends in the axial direction from the front end part 7 to the rear end part 8, respectively. Both end parts 7, 8 and the stator 2, respectively, the inner shell 5, if present, define the inner region 9. This inner region 9 contains the rotor 1. Further, both end parts 7, 8, the stator 2 and the outer shell 6 define the outer a region 10 which surrounds the inner region 9 radially from the outside. Preferably, further, both end parts 7, 8 and the outer shell 6 encapsulate the rotor 1 and the stator 2 according to the type of protection Ex d. The term "type of protection Ex d" has a stable meaning for the specialist. Appropriate implementations of such encapsulation are also familiar to those skilled in the art.

The inner region 9 and the outer region 10 are connected to each other and communicate through the recesses 11, so that the air 12 can flow from the inner region 9 to the outer region 10, and from there back to the inner region 9. If there is an inner shell 5, then the recesses 11 may be present in the inner shell 5. The air 12 flowing from the inner region 9 to the outer region 10 and vice versa forms the internal cooling circuit of the electrical machine.

The internal cooling circuit is usually single or double flow, but exceptions are possible in principle. With a single-flow internal refrigeration circuit according to FIG. 1, near both end parts 7, 8, there is one recess 11 each. Through one of both recesses 11, air 12 flows from the inner region 9 to the outer region 10, through the other of both recesses 11, air flows from the outer region 10 to the inner region 9. When In a dual-flow internal cooling circuit (not shown, but can also be implemented), there is additionally another recess 11 approximately in the middle between both end parts 7, 8. In this case, air 12 through both recesses 11 near both end parts 7, 8 flows from the outer region 10 into the inner region 9, and flows from the inner region 9 to the outer region 10 through a recess located between them. These and, if necessary, other embodiments of the internal cooling circuit are widely known to specialists. Therefore, they do not require further explanation.

In both end parts 7, 8 pipes 13 are fixed. These pipes 13 run axially. The pipes 13 respectively extend from the front end part 7 over the outer region 10 to the rear end part 8. The pipes 13 are usually fixed in the end parts 7, 8 in such a way that they can no longer be removed from the end parts 7, 8 without breaking. For example, they can be welded to the end parts 7, 8.

Pipes 13 as illustrated in FIG. 2 as a rule, when viewed in the tangential direction, are arranged with a distribution at an angle of more than 180° about the axis 4 of rotation. Shown specifically in FIG. 2 design, as well as shown in Fig. 2, the number of pipes 13, however, should be understood as an example only. On FIG. 2, only a few tubes 13 are provided with reference symbols so as not to clutter up FIG. 2. Often the tubes 13, when viewed in the tangential direction, are arranged in a distribution around the axis of rotation 4 at an angle even greater than 270°, sometimes even as shown in FIG. 2, essentially, around the entire circumference. As a rule, the pipes 13 are located, further, relative to the vertical plane E, containing the axis of rotation 4, in essentially equal parts on both sides of this plane E.

On the front end part 7 on its side facing away from the outer shell 6 - i. e. in the axial direction - the front protective element 14 is mounted. In FIG. 3 is shown in the fragment. The execution of the connection between the front end part 7 and the front protective element 14 is such that a liquid-tight protection is obtained. The front end part 7 and the front protective element 14 thus surround the front hollow space 15.

For liquid-tight protection between the front end part 7 and the front protective element 14, sealing elements 16 can be arranged. These sealing elements 16 can be embodied, for example, as O-rings. If necessary, the front protective element 14 and/or the front end part 7 may have recesses 17 for the sealing elements 16. However, other types of sealing are also possible. For example, the front guard 14 may be welded to the front end 7.

Similarly, on the rear end portion 8, on its side facing away from the outer shell 6, a rear shield 18 is fitted, so that the rear end portion 8 and the rear shield 18 enclose the rear hollow space 19. element 18 is generally similar to the connection between the front end part 7 and the front protective element 14. In particular, sealing elements 20 can also be present here, including recesses 21 for sealing elements 20, if necessary, and welding is also possible here.

Pipes 13, as depicted in FIG. 1 and FIG. 3 exit in both hollow spaces 15, 19. Further, the front hollow space 15 has a connection 22 through which a liquid cooling medium 23 can be supplied to the front hollow space 15. This liquid cooling medium 23 is typically water. In some cases, however, it may also be a different medium, such as oil. Connection 22 can be installed if necessary. In the images of Fig. 1 and FIG. 3, a radial approach to the front hollow space 15 is carried out. However, an axial approach to the front hollow space 15 is also possible.

Pipes 13 as illustrated in FIG. 3 have an inner diameter d1 and an outer diameter d2.

The pipes 13 are at a radial distance a2 from the stator 2. If there is an inner shell 5, this distance a2 is preferably determined from the inner shell 5. Preferably, the corresponding radial distance a2 is at least the same as the inner diameter d1. Even better, if the corresponding radial distance a2 is at least the same as the outer diameter d2. This ensures, in particular, that both end parts 7, 8 in their radially inner region have a sufficiently large radial extension to the stator 2, in which no pipes 13 are located, so that a corresponding protective element 14, 18 can be located there. if necessary, including the sealing element 16, 20.

On FIG. 4 shows a possible embodiment of one of the tubes 13. For others not shown in FIG. 4 pipes 13, similar reasoning is valid.

In accordance with the image in Fig. 4, the pipe 13 is designed as a double-walled pipe 13. Thus, it has an inner pipe 25 located inside and an outer pipe 26 surrounding this inner pipe 25. The inner pipe 25 conducts a liquid cooling medium 23. The outer pipe 26 in the outer region 10 flows around the air 12, those. air 12 of the internal cooling circuit. The distance between the inner tube 25 and the outer tube 26 should be as small as possible. If necessary, a relatively good thermally conductive medium 27, such as oil, gel or glue, can be placed between the inner tube 25 and the outer tube 26.

On FIG. 5 also shows a possible embodiment of one of the pipes 13. This embodiment is an alternative to the embodiment of FIG. 4. For others not shown in FIG. 5 pipes 13, as before, similar reasoning is valid.

In accordance with the image in Fig. 5, the pipe 13 is designed as a single-walled pipe 13. It conducts the liquid cooling medium 23 on the inside and flows around the outside of the air 12 flowing in the outer region 10, i.e. air 12 of the internal cooling circuit.

In the case of execution according to FIG. 5 preferably, in accordance with the image in FIG. 6, a detector device 28 is located in the outer region 10. This detector device 28 serves to determine whether there is liquid in the outer region 10, i. liquid cooling medium 23. Such detector devices 28 are widely known in the art. For example, in a relatively deep region of the outer shell 6, a small recess 29 may be located, in which the liquid cooling medium 23 can collect if it exits the pipes 13 and thereby enters the outer region 10. In the recess 29, as a detector device 28 the ends of the conductors 30 can be arranged, which, as a result of this accumulation of liquid cooling medium 23, are connected to each other in a conductive manner.

A similar implementation can be used according to FIG. 7 for the inner region 9. The embodiment of FIG. 7, if necessary, can be implemented alternatively or in addition to the implementation of FIG. 6.

The execution according to Fig. 6 and/or FIG. 7 can in principle also be combined with the construction of pipes 13 according to FIG. 4. In the case of double-walled pipes 13, however, this is not required.

Within the scope of the present invention, the liquid cooling medium 23 is both supplied to the anterior hollow space 15 and removed from it. This is discussed in more detail below in conjunction with FIG. 2.

According to FIG. 2, the front cover 14 has at least one baffle 31. This baffle 31 can extend, for example, vertically, as illustrated in FIG. 2. By means of a partition 31, the front hollow space 15 is divided into at least two sub-regions 32, 33. Part of the pipes 13 extends into the sub-region 32, the other part of the pipes 13 extends into the sub-region 33. The sub-region 32 has a connection 22, through which the front hollow space 15 - more specifically, in the sub-region 32 of the anterior hollow space 15 - a liquid cooling medium 23 is supplied. The other sub-region 33 has a connection 34 through which the liquid cooling medium 23 is discharged from the anterior hollow space 15, more specifically from the other sub-region 33 of the anterior hollow space 15. Thus , this liquid cooling medium 23 flows first through connection 22 into sub-area 32, then flows through pipes 13 leading into sub-area 32 into the rear hollow space 19, then flows through pipes 13 out of sub-area 33 back into sub-area 33, and from there through connection 34 is discharged from the anterior hollow space 15.

These two sub-regions are thus separated from each other by means of a barrier 31 in a liquid-tight manner. Further, the anterior hollow space 15 - with the exception of the connections 22, 24 for inlet and outlet of the liquid cooling medium 23 and the accesses to the axially extending pipes 13 - is liquid-tight. Similarly, the rear hollow space 19, with the exception of the access to the axially extending pipes 13, is liquid-tight.

Summarizing, we can say that the present invention relates to the following aspect.

The electric machine has a rotor 1 and a stator 2, the rotor 2 being mounted for rotation about an axis 4 of rotation. The rotor 1 is surrounded radially on the outside by a stator 2, and the stator 2 is surrounded by an outer shell 6 at a radial distance a1. the rotor 1 has an inner region 9 and these end portions 7, 8, the stator 2 and the outer shell 6 define an outer region 10 surrounding the inner region 9 radially from the outside. The inner region 9 and the outer region 10 are connected to each other and communicate with each other via recesses 11 so that air 12 from the inner region 9 can flow into the outer region 10 and from there back again. In the end parts 7, 8, axially extending pipes 13 are fixed, which run between the end parts 7, 8 in the outer region 10. On these end parts 7, 8, on their sides facing away from the outer shell 6, one protective element 14 is impermeable to liquid. 18, so that these end portions 7, 8 and these protective elements 14, 18 close respectively one hollow space 15, 19. The front hollow space 15 is divided by a partition 31 into at least two sub-regions 32, 33. exits into one or another sub-region 32, 33. In each of the sub-regions 32, 33 there is one connection 22, 34 for supplying or, respectively, for discharging liquid cooling medium 23.

This invention has many advantages. In particular, the cooling of the electric machine can be greatly improved. Due to this, with the same structural dimensions and the same or even reduced weight, the electric machine can be operated with more power. Experiments have shown that a power increase of approximately 25% can be realized without problems. Further, the noise emission of the electric machine can be reduced.

Although the present invention has been described and illustrated in detail with respect to the preferred embodiment, however, the invention is not limited to the disclosed examples and other variations may be derived by one skilled in the art without departing from the protection scope of the present invention.

Claims (22)

1. Encapsulated electric machine with air internal cooling circuit and liquid external cooling circuit, - moreover, the electric machine contains a rotor (1) and a stator (2), - moreover, the rotor (2) is made with the possibility of rotation around the axis (4) of rotation of the electric machine, - moreover, if you look around the axis (4) of rotation, then the rotor (1) is surrounded by the stator (2), and the stator (2) at a radial distance (a1) is surrounded by an outer shell (6), - with the radial distance (a1) varying, - moreover, the outer shell (6), when viewed in the direction of the axis (4) of rotation, respectively extends from the front end part (7) to the rear end part (8), so that the front and rear end parts (7, 8) and the stator ( 2) limit the inner region (9) containing the rotor (1), and the front and rear parts (7, 8), the stator (2) and the outer shell (6) limit the outer region (10) surrounding the inner region (9) radially from the outside , - moreover, the inner region (9) and the outer region (10) are connected, communicating with each other, by means of recesses (11), so that air (12) from the inner region (9) can flow into the outer region (10), and from there again back to the inner area (9), - moreover, the pipes (13) passing axially are fixed in the front and rear end parts (7, 8), respectively, so that the axially passing pipes (13) each extend from the front end part (7) along the outer region (10) to the rear end part ( eight), - moreover, the pipes (13) passing axially, when viewed around the axis (4) of rotation, are located with a distribution around the axis (4) of rotation at an angle of more than 180°, - moreover, on the front and rear end parts (7, 8) on their side, respectively, facing away from the outer shell (6), the front and, respectively, the rear protective element (14, 18) are impermeable to liquid, so that the front end part (7) and the front protective element (14) covers the front hollow space (15), and the rear end part (8) and the rear protective element (18) cover the rear hollow space (19), wherein the axially extending pipes (13) enter the anterior and posterior hollow spaces (15, 19), and - at least the front hollow space (15) has a connection (22) for supplying a liquid cooling medium (23), - moreover, the front and rear end parts (7,8) and the outer shell (6) encapsulate the rotor (1) and the stator (2) according to the type of protection Ex d. 2. Electric machine according to claim 1, characterized in that the rear hollow space (19) has a connection (24) for draining liquid cooling medium (23). 3. Electric machine according to claim 1, characterized in that the front hollow space (15) is divided into at least two sub-regions (32, 33), so that one part of the axially extending pipes (13) enters one of the sub-regions (32, 33), and the other part of the pipes (13) passing axially enters another of the sub-regions (32, 33), and the connection (22) for supplying liquid cooling medium (23) is located in one sub-region (32), and in the other sub-region (33 ) a connection (34) is located for draining the liquid cooling medium (23) from the front hollow space (15). 4. Electric machine according to any one of the preceding claims, characterized in that the axially extending tubes (13) have an inner diameter (d1) and an outer diameter (d2), and the axially extending tubes (13) are located at a corresponding radial distance from the stator (2) (a2), which is at least the same as the inner diameter (d1). 5. Electric machine according to claim 4, characterized in that the corresponding distance (a2) from the axially extending pipes (13) to the stator (2) is at least the same as the outer diameter (d2). 6. Electric machine according to any one of paragraphs. 1-5, characterized in that the axially passing pipes (13) are made as double-walled pipes, each of which has an inner pipe (25) conductive liquid cooling medium (23) and an outer pipe (26) that surrounds the inner pipe (25 ) and which is surrounded by air (12) flowing in the outer region (10). 7. Electric machine according to any one of paragraphs. 1-5, characterized in that the axially passing pipes (13) are made as single-walled pipes, which carry the liquid cooling medium (23) inside, and outside are flowed around by air (12) flowing in the outer region (10). 8. Electric machine according to claim 6 or 7, characterized in that in the inner region (9) and/or in the outer region (10) there is a detector device (28) for detecting liquid. 9. An electric machine according to any one of the preceding claims, characterized in that the axially extending pipes (13), when viewed around the axis of rotation (4), are arranged in a distribution around the axis of rotation (4) at an angle of more than 180°. 10. Electric machine according to any one of the preceding claims, characterized in that the stator (2) is surrounded by an inner shell (5) without a gap, and the inner shell (5) is located at a radial distance from the outer shell (6).

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