WO2006034922A1

WO2006034922A1 - Devices for dissipating heat from electrical machines

Info

Publication number: WO2006034922A1
Application number: PCT/EP2005/054006
Authority: WO
Inventors: Frank Kopf; Markus Liedel; Bernd Wieland; Hans-Peter Dommsch; Michael Schermann; Albrecht Steinborn; Hinnerk Lepthin
Original assignee: Robert Bosch Gmbh
Priority date: 2004-09-30
Filing date: 2005-08-15
Publication date: 2006-04-06
Also published as: DE102004047605A1; EP1797640A1

Abstract

The invention relates to an electrical machine and, in particular, a brush motor, comprising devices for dissipating heat from the electric motor, in which bearing points and brushes are, in particular, cooled.

Description

Devices for cooling electrical machines

State of the art

The present invention relates to an electrical machine with a device for cooling.

In electrical machines and in particular in electric motors which have a contact via brushes, the service life is usually determined by the wear of the carbon brushes. It has been found that different factors determine the wear. Among other things, the wear depends on the coal mixture, the smooth running of the commutator, the self-heating by the operation and the ambient temperature. In order to improve the service life of the electrical machines, it is therefore useful to make measures to heat the electric machine.

Another problem with respect to the life of electrical machines results from the life of the bearings of the armature shaft. Excessive heating of the bearings can easily lead to bearing damage. In contrast to a motor stall due to worn carbon brushes, bearing damage can cause severe consequential damage to the electrical machine. Thus, must Ensure that measures to prevent the heating of the brushes of the electric machine no additional heat can reach the bearings of the armature shaft and there can lead to bearing damage.

Advantages of the invention

An electrical machine according to the invention with the features of claim 1 has the advantage that during operation of the electric machine forced cooling takes place. This is inventively achieved in that devices for generating a cooling air flow are arranged on the shaft or connected to the shaft, rotating components. Thus, when the rotating shaft or components rotating with the shaft, a cooling air flow is generated, which brushes and / or bearings of the shaft can cool. The devices for generating a cooling stream are preferably ribs and / or blades and / or wings.

The dependent claims show preferred developments of the invention.

Particularly preferred devices for generating a cooling air flow are arranged on a side surface of a commutator of the electric machine.

In order to achieve a particularly compact and cost-effective manufacturability of the integrated devices for generating a cooling air flow, such devices are preferably provided on an axial insulation of an anchoring iron. For example, if the insulation is made of plastic, the devices for producing an airflow, such as ribs, blades, wings, etc., can be made simultaneously with the insulation. More preferably, the tie rod has axial vent holes and insulation is formed on a first axial side and a second axial side of the tie rod, wherein the devices for generating a cooling air flow formed on the first axial side generate an axial cooling air flow such that cooling air is passed through the axial vent holes and the devices for generating a cooling air flow formed on the opposite second axial side of the insulation generate a radial air flow for discharging the air flows guided through the axial ventilation bores of the armature iron radially outward. In this case, the devices generating the radial airflow are preferably arranged on the side of the armature iron on which a movable bearing of the shaft is also arranged. This prevents heated air from being conducted to the bearing of the shaft and contributing to excessive heating of the bearing.

Particularly preferably, the anchoring iron is formed from a plurality of sheets and a device for generating a cooling air flow is formed on at least one of the axially lying outer sheets. The devices for generating the cooling air flow can be integrally formed in the sheet by a stamping and / or forming step. Particularly preferred are the devices formed in an outermost sheet for generating a cooling air flow blades, which in particular have the shape of a spherical segment or a crescent.

According to another preferred embodiment of the invention, the anchor iron is formed from a plurality of sheets, which each have at least one axial passage opening. The individual sheets are arranged in such a way to each other that at least two adjacent through holes of two sheets to each other in Circumferentially arranged offset. By this staggered arrangement of the passage openings of the sheets, a cooling air flow can also be generated during a rotation of the armature iron.

According to another preferred embodiment of the present invention comprises an electric machine, an armature and a shaft which is mounted on a bearing. The bearing comprises a bearing component and a bearing carrier, via which the bearing is fixed to the electric machine. The bearing component comprises a hollow cylindrical portion and a cover portion. The covering area is arranged outside of a bearing carrier in order to enable heat removal from the bearing via the hollow cylindrical area and the covering area. The shaft is stored in the hollow cylindrical area. As a result, heat can be emitted from the shaft via the cover area arranged on the outside, so that excessive heating of the bearing point can be prevented.

The bearing carrier is preferably a part of a housing of the electric machine and the cover region and / or the hollow cylindrical region of the bearing contact the housing, so that a heat transfer to the housing can take place.

According to another preferred embodiment of the present invention, an electric machine comprises a shaft supported at a first and a second bearing point, the first bearing point comprising a bearing, a bearing holder and a bearing carrier and an opening being formed in the bearing carrier. The bearing holder has at least one extended portion, which is passed through the opening in the bearing carrier to heat after to be able to deliver outside. Thus, heat can be released directly from the storekeeper to the outside.

The extended portion of the bearing holder preferably has a size which is at least a quarter of a total surface area of the bearing holder. As a result, sufficient heat dissipation can be ensured.

More preferably, the bearing holder has a region which is arranged above an opening formed in the bearing carrier. The area of the bearing holder covers the opening completely or partially. This can be done by the bearing holder through the opening in the bearing carrier to the outside an additional heat.

According to another preferred embodiment of the present invention, an electrical machine comprises a shaft with an armature, wherein the armature comprises an armature bar and an element for isolating the armature bar from the shaft is arranged between the armature bar and the shaft. As a result, it can be prevented that the anchoring iron, which has a relatively large area, dissipates its heat via the shaft to adjacent components, in particular the brushes and / or the bearings.

Particularly preferably, the insulating element is an insulating bush, preferably made of plastic. More preferably, the bushing is part of an insulating mask of the armature iron, which separates a winding from the anchor iron. As a result, the insulation element can be produced particularly inexpensively.

In order to prevent damage to the likewise heating insulation element when heated during operation, is preferably formed between the shaft and the anchor iron a positive connection.

According to another preferred embodiment of the present invention, an electric machine according to the invention comprises a shaft which has a recess, in particular a blind hole, at at least one bearing point. The shaft is thus formed in the region of the bearing as a hollow shaft. It can thereby be achieved that a heat flow emitted by the armature is for the most part discharged into the region of the shaft in which no recess is formed. A bore depth or a bore diameter can be determined individually depending on the electrical machine. Thus, a heat-conducting cross section of the shaft can be selectively reduced only in the region of the bearing. The heat flow can thus be dissipated away from the camp in less critical areas of the electric machine over the full wave cross section.

More preferably, a commutator is disposed on the hollow portion of the shaft. This prevents that an unwanted heat flow through the commutator is guided to the brushes.

According to a further preferred embodiment of the invention, the Hohlwellenbreich is formed over the entire length of the shaft.

More preferably, a diameter of the hollow shaft area changes continuously or stepwise over the length of the shaft, ie in one or more stages. Preferably, a substantially aligned in the radial direction of the shaft bore is formed for additional cooling. The radial bore thus extends from the interior of the hollow shaft portion to the outside of the shaft. It should also be noted that in the region of the hollow shaft, improved cooling is possible by supplying cooling air into the hollow region of the shaft.

It should be noted that the above-described individual measures for the cooling of an electric machine can be used alone or in any desired combination. In particular, the heat removal measures according to the invention are used to defrost the brushes and / or a bearing close to the brushes.

drawing

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the drawing is:

1 shows a schematic side view of an electrical machine with devices integrated on the rotating components for generating a cooling air flow according to a first exemplary embodiment of the present invention, FIG.

FIG. 2 shows a perspective view of an electrical machine with devices for generating a cooling air flow integrated on the rotating components according to a second exemplary embodiment of the present invention,

Figure 3 is a schematic side view of an electrical machine with integrated devices on the rotating components for generating a cooling air flow according to a third embodiment of the present invention,

FIG. 4 shows a schematic sectional view of an electrical machine with a device for cooling the electric machine according to a fourth exemplary embodiment of the present invention,

FIGS. 5a and 5b are views of an electric machine with a cooling device according to a fifth exemplary embodiment of the present invention,

Figure 6 is a schematic sectional view of an electric machine with a cooling device according to a sixth embodiment of the present invention and

Figure 7 is a schematic sectional view of an electric machine with a cooling device according to a seventh embodiment of the present invention.

Description of the embodiments

Hereinafter, an electric machine with a cooling device according to a first embodiment of the present invention will be described with reference to FIG.

The electric machine according to the first

Embodiment in Figure 1 comprises an armature shaft 1 and an armature 2. At armature 2, an anchor bracket 3 is fixed to the shaft 1 in a known manner. In the tie bar 3 eight axial through holes 4 are formed, which over the Whole length of the anchor wire 3 run. At armature 2, more precisely at the outermost in an axial direction of the armature plate, a plurality of blades 5 is formed. The blades 5 are arranged outside the outer circumference of the axial passage openings 4 as shown in FIG. The blades 5 thereby provide a radial air flow to discharge heated air, which emerges from the axial vents 4, radially outward. This prevents that the air heated in the axial passage openings 4 can flow off in the axial direction and thereby heat a commutator or brushes or a bearing of the shaft 1.

It should be noted that preferably at the other axial end of the armature 2, not shown, also vanes or ribs or vanes, etc. are formed to generate an axial flow of air through the axial through-holes 4. Thus, by these blades, etc., an axial flow can be generated and the air in the axial through-holes 4 to heat and the heated air are discharged via the blades 5 radially outward. This allows the electric machine to be cooled.

It should be noted that the device for generating a cooling air flow, such as blades, vanes, ribs, etc., for example, on the commutator and / or an insulating mask of the armature and / or the armature itself can be formed. Particularly preferably, the devices for generating an air flow are integrally formed with the respective components, so that they are particularly inexpensive to produce.

FIG. 2 shows an electrical machine according to a second exemplary embodiment of the present invention. In FIG. 2, identical or functionally identical parts are designated by the same reference numerals as in FIG. As can be seen from FIG. 2, the electric machine of the second exemplary embodiment comprises a shaft 1 and an armature 2. An armature bar 3 is also arranged on the shaft 1. The anchor bar 3 of the second

Embodiment is formed of a plurality of steel sheets. As shown in FIG. 2, a blade profile 6 is integrally formed on the outermost steel sheet of the armature iron 3 in the region of each axial passage opening 4. The blade profiles 6 are formed as spherical sections, more precisely as a quarter of a ball. The blade profiles 6 can be made easily and inexpensively, for example, by punching and forming in the sheet.

The blade profiles shown in FIG. 2 serve, in particular, as axial fans in order to allow air to enter into the tie bar 3 for cooling the tie bar. The blade profiles 6 can also be produced via a drawing or embossing process.

FIG. 3 shows an electric machine according to a third exemplary embodiment of the present invention. Identical or functionally identical parts are again denoted by the same reference numerals as in the preceding embodiments.

As shown in FIG. 3, the electric machine of the third embodiment includes a commutator 7 on which a plurality of fins 8 are integrally formed. More specifically, six fins 8 are formed on an axial side surface of the commutator so that the fins rotate together with the shaft 1 upon rotation of the shaft 1 and generate a cooling air flow. FIG. 4 shows a schematic sectional view of an electrical machine according to a fourth exemplary embodiment of the present invention. The device for cooling of electric motors of the fourth embodiment is a special bearing component 9, in which the shaft 1 is mounted as a plain bearing. As shown in Fig. 4, the bearing member 9 comprises a hollow cylindrical portion 9a and a cover portion 9b. The hollow cylindrical portion 9a receives the end of the shaft 1. The cover area 9b is substantially a circular area and is arranged outside a housing 10 of the electric machine. In the housing 10, an opening 10a is provided, in which the bearing member 9 is arranged. A connection between the housing 10 and the bearing member 9 may be frictionally engaged or, for example, by welding or gluing o.Ä. getting produced.

Thus, when the shaft 1 heats up during operation, a very good heat transfer from the shaft 1 to the bearing component 9 and then into the environment can be achieved. In Figure 4, this is shown by the arrows Q. Another advantage of the embodiment is that the bearing member 9, the shaft from unwanted environmental influences such as salt and water o. can protect. This will further prevent bearing oil from being washed out. The area of the covering area 9b is in this case dimensioned so that a very good heat dissipation is possible.

FIGS. 5a and 5b show an electrical machine according to a fifth exemplary embodiment of the invention. In this fifth embodiment, a bearing 11 of the shaft of the electric machine is arranged in a bearing receptacle 10b of a housing 10 of the electric machine. The bearing receptacle 10b can be generated in a simple manner by means of forming. In the housing 10 are also first Through holes 10c and second through holes 10d formed. As can be seen from FIG. 5a, the bearing becomes

11 fixed by means of a bearing holder 12 on the housing 10. This is preferably realized by means of a frictional connection between the bearing holder 11 and the housing 10. As shown in Figure 5a, the storage holder comprises

12 a holding portion 12 a, on which the bearing 11 is held, and an extended portion 12 b, which is passed through the opening 10 c in the housing 10. Thus, the extended portion 12 b protrudes through the opening 10 c from the housing 10. As a result, heat can be released from a shaft 1 via the bearing 11 and the bearing holder 12 to the extended region 12b and from there to the ambient air. As can be seen from FIG. 5b, two extended regions 12b are provided in this exemplary embodiment. Furthermore, the bearing holder 12 also has two covering regions 12c, which partially cover the opening 10d in the housing 10. Heat can also be released through the openings 10d to the surroundings via the cover regions 12c.

In Figure 5a, the heat output is shown schematically by the arrows Q. The extended portions 12b of the bearing holder 12 thus act as a cooling lug, which project outwardly from the electric machine. Thus, an excessive heating of the shaft 1 can be prevented and thus also the bearing or the brush, which contact a commutator attached to the shaft.

FIG. 6 shows an electric machine according to a sixth embodiment of the present invention. According to the sixth embodiment, an insulation 13 is provided between a shaft 1 and an anchor iron 3. Since the anchor bar 3 due to a relatively large blockage by an anchor insulation and the armature winding relatively quickly In the prior art, this heat has hitherto been transmitted via the connection with the shaft 1 to the shaft 1 and thus to the bearings or a commutator and contact brushes. Therefore, as the inventive measure for heat dissipation of the bearings or the brushes in the sixth embodiment, the insulation 13 was formed such that it has a sleeve-like portion 13a and two axially end-face portions 13b and 13c. The sleeve-like portion 13a is thus disposed between the shaft 1 and the tie bar 3, and isolates the tie bar from the shaft. It should be noted that particularly preferably the female portion 13a of the insulation is a single component and the two end-side insulating portions 13b and 13c are also integral parts, so that easy manufacture and assembly is possible.

As a result of this insulation of the armature 3, the armature must deliver more heat to the air surrounding it. Therefore, no additional insulation is provided on the radially outer side of the armature 3.

Since plastic is preferably used for the insulation 13, a positive connection between the shaft and the tie bar 3 is advantageous since a frictional connection can be relatively easily destroyed due to the plastic relaxation in the female portion 13a. It should be noted that the positive connection must of course be isolated in order to prevent the unwanted heat release into the shaft.

FIG. 7 shows an electric machine according to a seventh embodiment of the present invention. As can be seen from FIG. 7, a blind hole 15 is formed in the shaft 1, so that the shaft 1 has a hollow shaft area 1a. In this embodiment, the Hollow shaft portion Ia a length such that a bearing 11 and a commutator 14 are arranged on the shaft at the hollow shaft portion Ia. As shown schematically in the arrows for heat transfer in Figure 7, the hollow shaft portion Ia has the effect that an outgoing of an anchor iron 3 heat flow in the two axial directions of the shaft occurs in different sizes. More specifically, a first large heat flow Q _{1 is} generated, which is guided by the anchor iron 3 in the shaft with full material cross-section and a second heat flow Q ₂ is directed in the direction of the hollow shaft portion Ia. By providing the blind hole 15 of the heat-conducting cross section of the shaft 1 is selectively reduced. This makes it possible that the bearing 11 and the commutator 14 can be arranged on the hollow shaft portion Ia, so that the heat output from the hollow shaft portion Ia on the bearing 11 and the commutator 14 is significantly reduced in comparison with the prior art. As a result, a heat load for the bearing or the brush 14 contacting the commutator is significantly reduced. The occurring heat flow is thus conducted in less critical areas over the waveband with full cross-section.

It should be noted that the measures illustrated in the embodiments for the cooling of electrical machines can be combined in any way. In particular, the hollow shaft regions shown in FIG. 7 can be combined as desired with each of the exemplary embodiments shown in FIGS. 1 to 6. Further, the other draining measures at the bearings of the fourth and fifth embodiments (Figs. 4 and 5a, 5b) may be arbitrarily combined with the air flow generating devices in the first to third embodiments. This also applies to the sixth embodiment, which in any way can be combined with the other embodiments shown.

Claims

claims

1. Electrical machine, comprising a shaft (1) with an armature (2), wherein on the shaft (1) or on the shaft together with rotating components devices (5, 6, 8) for generating a cooling air flow, in particular ribs and / or blades and / or wings are arranged.

2. Electrical machine according to claim 1, characterized in that on a side surface of a commutator (7) devices (8) are arranged for generating a cooling air flow.

3. Electrical machine according to one of the preceding claims, characterized in that devices for generating a cooling air flow are formed on an axially directed insulation component of an armature iron (3).

4. Electrical machine according to claim 3, characterized in that the anchoring iron (3) has axial passage openings (4) and on a first axial side of the anchoring iron (3) formed on the axially aligned insulating element devices for generating a Cooling air flow generate an axial flow of cooling air, which passes air through the axial passage openings (4) and on a opposite axial side of the armature on an axially directed isolation element formed devices for generating a cooling air flow generate a radial air flow to those through the axial passage openings (4) out Remove air flows radially.

5. Electrical machine according to claim 1, characterized in that the anchoring iron (3) is formed from a plurality of individual sheets and a device for generating a cooling air flow at one or both of the axially directed outermost sheet are formed.

6. Electrical machine according to claim 5, characterized in that the devices for generating a cooling air flow are integrally formed in the sheet, in particular in the form of a spherical section, on the axial passage openings (4).

7. Electrical machine according to claim 1, characterized in that the anchoring iron (3) is formed from a plurality of individual sheets, wherein the individual sheets each have at least one axial passage opening and wherein the individual sheets are arranged to each other such that at least two adjacent Through openings of adjacent sheets are arranged offset in the circumferential direction.

8. An electric machine comprising a shaft (1) and an armature (2), wherein the shaft (1) at a first Bearing and is mounted on a second bearing, wherein the first bearing is designed as a floating bearing and a bearing member (9) has a hollow cylindrical portion (9a) and a cover

(9b), wherein the cover portion (9b) is disposed outside of a bearing support (10) for removing heat from the shaft (1) via the hollow cylindrical portion (9a) and the cover portion

(9b).

9. Electrical machine according to claim 8, characterized in that the bearing carrier (10) has an opening

(10a), in which the bearing component (9) is frictionally fixed.

10. Electrical machine, comprising a shaft (1) and an armature (2), wherein the shaft (1) is mounted at a first bearing point and at a second bearing point and wherein the first bearing a bearing (11), a bearing holder (12 ) and a bearing carrier (10), wherein in the bearing carrier (10) at least one opening (10c) is formed and the bearing holder (12) has at least one extended portion (12b) which through the opening (10c) in the bearing carrier (10). passed for heat dissipation.

11. Electrical machine according to claim 10, characterized in that the extended portion (12b) has a size which corresponds to at least a quarter of an entire surface of the bearing holder (12).

12. Electrical machine according to claim 10 or 11, characterized in that the bearing holder (12) has a covering region (12c), which is formed over a further opening (10d) formed in the bearing carrier (10). is arranged, wherein the cover portion (12c), the opening (10d) completely or partially covers.

An electric machine comprising a shaft (1) and an armature (2), the armature (2) comprising an anchor (3) and further comprising an element for isolating the armature (3) from the shaft (1) between the armature (3) and the shaft (1) is arranged.

14. Electrical machine according to claim 13, characterized in that the element for isolation is an insulating bushing (13a).

15. Electrical machine according to claim 14, characterized in that the bushing (13a) is a part of an insulating mask of the armature iron (3) which separates a winding from the armature iron (3).

16. Electrical machine according to one of claims 13 to 15, characterized in that between the shaft (1) and the tie bar (3) is a positive, in particular also insulated, connection is formed.

17. Electrical machine comprising a shaft (1) and an armature (2), wherein the shaft (1) is mounted at a first bearing point and at a second bearing point, and wherein the shaft (1) at the first bearing point a recess ( 15) such that the shaft

(1) comprises at the first bearing a hollow shaft region (Ia).

18. Electrical machine according to claim 17, characterized in that at the hollow shaft region (Ia) a first bearing point of the shaft is arranged.

19. Electrical machine according to claim 17, characterized in that at the hollow shaft region (Ia) a commutator (14) is arranged.

20. Electrical machine according to claim 17, characterized in that at the hollow shaft region (Ia) a commutator (14) is arranged.

21. Electrical machine according to one of claims 17 to

20, characterized in that the Hohlwellenbreich is formed over the entire length of the shaft.

22. Electrical machine according to one of claims 17 to

21, characterized in that a diameter of the hollow shaft portion (Ia) changes continuously or stepwise over the length of the shaft.

23. Electrical machine according to one of claims 17 to

22, characterized in that at least one substantially aligned in the radial direction bore to the outer circumference of the shaft is formed on the hollow shaft portion (Ia).