DE102007021917A1 - Electrical machine i.e. permanent magnet-excited electronically commutated engine, for driving pump i.e. water pump, in motor vehicle, has blower arranged in scatter field arising at axial end of rotor, and coupled with flux of rotor - Google Patents

Abstract

The machine has a separating can (5) for separating a rotor (2) from a stator (4) in a sealed manner. An blower (7) is arranged coaxial to the rotor. The blower is arranged outside the separating can, and the rotor is arranged within the separating can. The blower is arranged in a scatter field (6) arising at an axial end (2a) of the rotor. The rotor projects in an axial direction over an iron core (4a) of the stator. The blower is coupled with a leakage flux of the rotor and rotated with a rotation of the rotor. The blower is formed from magnetizable plastic.

Description

State of the art

The The present invention relates to an electric machine having a improved heat dissipation.

electrical Machines are known from the prior art in different configurations. Such electrical machines may be, for example, permanent magnet excited, be electronically commutated motors in a closed design. In the closed design, the rotor is in a so-called Slit pot arranged and can in the split pot of a liquid be surrounded. The stator is located outside the containment shell in dry area. On the rotor, for example, a pump o. Ä. fixed, to the liquid promote. In this closed design, the heat can in particular only by Heat conduction to casing and be delivered from there to the environment. This can be punctual high heat loads which cause damage on the electric machine can. For a better heat dissipation to enable it is known, ribs o. Ä. to provide on the components. However, in electrical machines, in which the rotor is arranged in the containment shell, such heat dissipation not appropriate. Such machines are for example for Drive of pumps in motor vehicles, for example as water pumps for one Cooling circuit used.

Advantages of the invention

The electrical according to the invention Machine with the features of claim 1, in contrast, the Advantage on that they have improved cooling of the electric machine can provide. This increases the life of the electric machine considerably. hereby Further, an improved power density of the electric machine be achieved. This is inventively achieved in that the electric machine a rotor, a stator, a containment shell, in which the rotor is arranged, and comprises a fan. The stator is while outside arranged the gap pot. The fan is also coaxial with the rotor arranged, with the fan also outside the Statortopfes is arranged. The fan is in a stray field, which at one axial end of the rotor during the operation of the electric Machine is formed, arranged. This is the fan with coupled to the leakage flux of the rotor and rotates during a rotation the rotor as well. As a result, an air movement outside of Gap pot achieved, which in particular the formation of punctual heat stress avoids. As a result, a long service life can be ensured. In this case, the invention is the electrical Machine very simple and can be provided inexpensively.

The under claims show preferred developments of the invention.

Preferably the rotor protrudes axially over the stator. hereby becomes the formation of a strong axial stray field at the axial end of the rotor possible. Further preferred are large Working air gap between rotor and inside of the can intended.

Further Preferably, the rotor comprises a plurality of permanent magnets. The rotor may, for example, comprise six or eight permanent magnets.

According to one preferred embodiment According to the invention, a number of poles of the rotor is equal to one Number of poles of the fan. Particularly preferred is the fan also equipped with permanent magnets, so that a synchronous Rotation between fans and rotor can be provided in a simple manner.

According to one Another preferred embodiment of the invention, the fan is integrally formed. The fan is preferred it is made of a magnetizable plastic and can z. B. by injection molding getting produced. As a magnetizable plastic, for example Plastoferrit or plastic-bound rare earth magnet materials be used.

According to one Another preferred embodiment of the invention, the fan comprises a first magnetization track and a concentrically arranged second magnetization track. The first and second magnetization tracks are each oppositely magnetized concentrically. These Design of the fan does not maximize the transferable torque from the rotor on the fan, However, it represents a very cost effective and easy-to-implement solution ready.

According to one Another preferred embodiment of the present invention the fan one piece Made of a sheet metal material and includes stamped and bent wing areas. The bent wing areas are arranged substantially in the axial direction of the fan. hereby This results in a simple form of a reluctance fan. The fan can thereby provided from a simple magnetically conductive sheet very inexpensive become.

Particularly preferably, the fan is rotatably mounted on a socket arranged on the outside of a bottom of the split pot. The base can be injection molded, glued or welded or attached in any other way. Alternatively, the fan is mounted on a housing of the electrical machine.

According to one Another preferred embodiment of the invention comprises the electrical Machine further an electronic unit, which in the axial direction of the rotor adjacent to the fan is arranged. Here is the fan arranged between the electronics unit and the rotor. hereby can EC motors (electronically commutated motors) in a closed design to be provided. By the arrangement of the electronic unit coaxial with the fan can be a constant cooling the electronic unit ensured during operation of the electric machine become. This is a failure of the electronics unit due of heat buildup problems excluded.

Further Preferably, the rotor comprises a remote from the bottom of the gap pot End of a pump wheel to promote a fluid, in particular for promotion a liquid. The impeller is firmly connected to the rotor and rotates together with the rotor. As a result, for example, an electrical Drive for a cooling water pump for a Vehicle to be provided, which is particularly compact and simple is constructed. Since the impeller is fixed directly on the rotor, results in particular in the axial direction a very small structure at low weight.

The electrical according to the invention Machine is used especially in vehicles as a feed pump or as a circulation pump o. Ä. used because it is very robust and easy and inexpensive to deploy can. However, it is also possible an inventive electrical Machine for example in building technology for heating pumps or other circulating pumps or even with compressors that run in encapsulated cans, such as B. refrigeration compressors, to use.

drawing

following become preferred embodiments the invention with reference to the accompanying drawings in Detail described. In the drawing is:

1 a schematic sectional view of an electric machine according to a first embodiment of the invention,

2 a schematic plan view of a fan of the first embodiment,

3 a schematic representation of a distribution of permanent magnet regions on the in 2 shown fan,

4 1 is a schematic representation of a distribution of permanent magnet regions in a fan according to a second embodiment of the present invention;

5 a schematic plan view of a fan according to a third embodiment of the present invention, and

6 a schematic side view of the in 5 shown fan.

Preferred embodiments the invention

The following is with reference to the 1 to 3 an electrical machine according to a first embodiment of the invention described in detail.

How out 1 can be seen, includes the electric machine 1 a rotor 2 at which a plurality of permanent magnets 3 is arranged. In this embodiment, four permanent magnets are arranged on the rotor. Furthermore, the electric machine includes 1 a stator 4 which is an iron core 4a and winding heads 4b includes. Between the rotor 2 and the stator 4 is a containment shell 5 with a floor 5a and a cylindrical wall area 5b arranged. The electric machine 1 is thus a permanently excited, electronically commutated machine in a closed design. The electronics are identified by the reference numeral 8th designated and in a housing 13 arranged the electric machine.

As further out 1 is apparent, is on the rotor 2 Coaxial with an impeller 10 arranged to promote a fluid, in particular a liquid. In the axial direction XX of the rotor 2 is also outside the split pot 5 a fan 7 arranged, which at a warehouse 9 on the outside of the floor 5a is rotatably mounted. The fan 7 is in detail in the 2 and 3 shown. How out 2 can be seen, the fan comprises a plurality of blades or blades 7a and a circular base plate 7b on which the blades 7a are arranged. A central opening 7c serves for fixation on the bearing 9 which, for example, a stub shaft o. Ä. is. The fan 7 is made of a permanent magnetic material and has four poles P on how out 3 is apparent. Thus, the number of poles of fans 7 and rotor 2 equal.

The impeller 10 sucks the fluid from a suction line 11 and conveys it radially into several pressure lines 12 , By using the containment shell 5 is the electric machine 1 thus in a dry area 1a and one with the fluid in Kon clock coming range 1b divided. How farther 1 can be seen forms in operation at an axial end 2a of the rotor 2 a strong axial stray field 6 in which the fan 7 is arranged. The stray field 6 goes over the containment shell 5 out. This causes the fan to rotate 7 together with the rotor 2 with the same speed. This causes a circulation of air in the area of the stator 4 and the electronics 8th instead of. As a result, it is avoided on the one hand that heat build-up areas form, at which points of high temperature could be present, which in particular the electronics 8th could harm. Thus, an air circulation within the dry area 1a the electric machine 1 achieved, in addition, no sealed shaft passage through the containment shell 5 necessary is. The storage of the fan 7 simply takes place at a warehouse 9 on the outside of the floor 5a , Alternatively, the fan could 7 also on the side of electronics 8th be stored.

Due to the same number of poles between fans 7 and rotor 8th there is a synchronous rotation of the two components. The fan 7 is preferably made of one piece, for example as an injection molded part of a magnetizable plastic.

Because the impeller 10 directly on the rotor 2 is arranged, also in the axial direction XX a very compact design can be achieved. The electric machine according to the invention with directly arranged impeller 10 can be used for example in motor vehicles as a cooling water pump or as an oil pump. The measure according to the invention thus leads to a simply constructed pump motor, which has a very long service life.

The following is with reference to 4 an alternative according to a second embodiment of a fan 7 described. How out 4 it can be seen, the fan points 7 two specially adapted magnetic tracks, namely an outer magnetic track 7d and an inner magnetic track 7e on which concentric to the outer magnetic track 7d is. Each magnetic track six poles are provided in each case. As a result, it is possible in particular to respond to a greatly varying three-dimensional course of the leakage flux at the stray field. In 4 the letter N designates a north pole and the letter S a south pole. Otherwise the fan is the same 7 that of the first embodiment, so that reference may be made to the description given there.

The 5 and 6 show another alternative fan 17 according to a third embodiment of the present invention. The fan 17 is punched out of a sheet material and individual blades are bent by 90 ° to the sheet metal base plate. The shovels are in the 5 and 6 with the reference number 17a denotes the base plate by the reference numeral 17b , The fan 17 is doing a sleeve 17c similar to the first embodiment stored. Thus, the fan can 17 of the third embodiment in the simplest manner can be produced from a magnetically conductive sheet by punching and bending. The number of blades 17a and thus the gaps in the base plate 17b in this case coincides with the number of poles of the rotor of the electric machine, so that a reluctance fan matching the leakage flux results. Thus, by this particularly simple and inexpensive measure sufficient air circulation in the non-fluid flowing through the area 1a the electric machine 1 be achieved. In particular, damage to the electronics can be prevented.

Claims (10)

Electric machine comprising a rotor ( 2 ), a stator ( 4 ), a containment shell ( 5 ), which the rotor ( 2 ) from the stator ( 4 ) in a sealing manner, and a fan ( 7 . 17 ) which is coaxial with the rotor ( 2 ) is arranged, wherein the fan ( 7 . 17 ) outside the containment shell ( 5 ) is arranged and the rotor ( 2 ) within the containment shell ( 5 ) and wherein the fan ( 7 . 17 ) in one at an axial end ( 2a ) of the rotor ( 2 ) occurring stray field ( 6 ) is arranged. Electrical machine according to claim 1, characterized in that the rotor ( 2 ) in the axial direction (XX) via an iron core ( 4a ) of the stator ( 4 ) protrudes. Electrical machine according to one of the preceding claims, characterized in that the rotor ( 2 ) a plurality of permanent magnets ( 3 ). Electrical machine according to one of the preceding claims, characterized in that a number of poles of the rotor ( 2 ) equal to a number of poles of the fan ( 7 . 17 ). Electrical machine according to one of the preceding claims, characterized in that the fan ( 7 . 17 ) in one piece, in particular of a magnetizable plastic is formed. Electrical machine according to one of the preceding claims, characterized in that the fan ( 7 ) a first magnetization track ( 7d ) and a concentric second magnetization track ( 7e ), wherein the first and second magnetization tracks ( 7d . 7e ) are each magnetized opposite each other. Electrical machine according to one of claims 1 to 3, characterized in that the fan ( 17 ) is made in one piece from a sheet metal material and stamped and bent blades ( 17a ). Electrical machine according to one of the preceding claims, characterized in that the fan ( 7 . 17 ) at one on an outside of a floor ( 5a ) of the split pot ( 5 ) arranged bearing element ( 9 ) is rotatably mounted. Electric machine according to one of the preceding claims, further comprising electronics ( 8th ), which in the axial direction (XX) of the rotor (XX) 2 ) adjacent to the fan ( 7 . 17 ) is arranged so that the fan ( 7 . 17 ) between the electronics ( 8th ) and the containment shell ( 5 ) is arranged. Electrical machine according to one of the preceding claims, characterized in that on one to the ground ( 5a ) of the split pot ( 5 ) opposite end of the rotor ( 2 ) an impeller ( 10 ) is arranged for conveying a fluid, in particular for conveying a liquid, which together with the rotor ( 2 ) turns.