WO2012084511A2

WO2012084511A2 - Electrical machine having a fastening apparatus for magnets

Info

Publication number: WO2012084511A2
Application number: PCT/EP2011/071991
Authority: WO
Inventors: Andre Corvini; Julius GEORGE MANNAN
Original assignee: Robert Bosch Gmbh
Priority date: 2010-12-20
Filing date: 2011-12-07
Publication date: 2012-06-28
Also published as: EP2656483A2; CN103392287A; JP2014500702A; CN103392287B; DE102010063514A1; WO2012084511A3

Abstract

The invention relates to an electrical machine (10), in particular a starter apparatus for an internal combustion engine, having a housing (28) in which at least one magnet (31) and at least one mild steel (200) are accommodated in an encapsulated manner. The at least one magnet (31) and the at least one mild steel (200) are held in the housing (28) at least in the radial direction and in the circumferential direction by an annular positioning device (208).

Description

Description title

Electric machine with fastening device for magnets. State of the art

DE 101 48 652 A1 relates to a DC machine and a method for fixing magnets to a pole housing of a DC machine. On the pole housing, a magnet holding device is attached to which the magnets, which are in particular permanent magnets, are held. The magnet holding device is fixed to the inner periphery of the pole housing and formed by an annular holding cage. The holding cage is provided with a running in the axial direction, continuous slot and

resilient, preferably formed in one piece. The holding cage is worked out of a board, preferably punched and then brought by rolling into its ring shape. The holding cage according to DE 101 48 652 A1 is held non-positively in the pole housing of the DC machine. The frictional connection is due to

material-induced restoring forces of the rolled into its ring shape holding cage generated, which may be increased by overpressing the rolled holding cage. The holding cage has pockets for receiving a respective magnet.

In the electrical machines known from the prior art, the problem arises of high tolerance chains and the associated associated tolerances. Are for example magnets, in particular permanent magnets with separate holders or

Fastening springs attached to the inner peripheral surface of the pole housing, especially river iron via snap hooks or in projections on the inner peripheral surface of the pole housing engaging openings of the magnet holder for receiving the individual magnets formed in several parts, so the problem of adding tolerances occurs. Adding tolerances, for example between the brushes and the magnets, which are often incorporated with a circumferential angle error with respect to each other, cause the commutation angle can not be met with sufficient accuracy or with a very high tolerance.

Inaccuracies in the position while maintaining the commutation angle of the electric machine, but inevitably reduce the power of the electrical Machine. If the previously multi-part magnet holder is then fixed via stampings or impressions that are mounted in the pole housing, so is the

Positional accuracy of the magnets and the brushes defined by the accuracy of these indentations or stampings. If inaccuracies occur during the introduction of the stampings into the material of the pole housing, this tolerance is added to the already very long tolerance chain.

DESCRIPTION OF THE INVENTION According to the invention, it is proposed to use an annular positioning device on an electric machine which supports both the magnets, in particular the permanent magnets used, and the flux irons, both in the tangential direction and in the radial direction, and which provides improved positioning as opposed to previously used for positioning the magnets or the river iron springs allows. The ring-shaped positioning device in particular gives the positioning of the retention of the original

Mounting positions of magnets and river iron characterized better stability, that is formed between the annular positioning device and the pole housing of the electric machine, an anchor-shaped fixation. This, preferably designed as a form-locking connection between the annular positioning device and the pole housing attachment, on the one hand vibration insensitive and on the other hand also independent of temperature. This means that even with load peaks of the electric machine, as they can occur in continuous operation or even in short-term operation, the different coefficients of thermal expansion of an example made of plastic material annular positioning device and the pole housing usually made as a metallic tube, the quality of the attachment not

affect. Rather, it is designed in such a way that the magnets, as well as the river iron, retain their original mounting position in the tangential and radial direction through the annular positioning device, so that no

Adjust power losses on the electric machine, in particular a starter device for an internal combustion engine of a motor vehicle.

Essentially, for example, the ring formed as a plastic ring

Positioning device designed such that it as an injection molded part

Plastic material is made and which both axial and radial and tangential having extending support surfaces. These support surfaces hold the magnets and the river iron in the original mounting position within the pole housing.

Preferably, for example, preferably designed as a plastic ring-shaped positioning device is fastened by snap closures in the pole housing, so that immediately with the mounting of the same one hand, a defined installation position of the annular positioning device results and inevitably by this by direct contact with both the river iron and with Magnets, in particular the permanent magnet whose original mounting position defined on the inner circumferential surface of the pole housing of the electric machine is permanently maintained. In addition to the formation of the ring-shaped

Fixing device as a plastic component, this can also be made as a hybrid component, i. a component of the multi-part formed in this case, annular

Fastening device can be made as a plastic component, the other example of metallic material. For example, in the way of

Injection molding process are injection-molded around a metallic ring plastic material, wherein the metallic ring designed as a hybrid component annular

Positioning device gives the necessary mechanical stability. To the

Plastic material can be formed in an advantageous manner on the one hand, the latching of the formed as a hybrid component annular positioning device and the support surfaces in the axial, radial and tangential direction for the magnets or the river iron, while on the other hand, there is the possibility of inventively proposed ring-shaped positioning device not in Form ways of injection molding by molding a metallic ring with plastic material, but to provide two separate components, ie a plastic ring and a metallic one

Ring, which are merged in a separate assembly step during assembly. In this alternative embodiment of the inventively proposed annular fastening device, for example, a resiliently formed latching between the pole housing and the metallic ring of the two-part annular positioning device can be created. This has a more elastic spring behavior, especially when vibrations occur, compared with a locking, which is formed for example by way of the plastic injection molding process around a metallic ring. Brief description of the drawings

With reference to the drawing, the invention will be described in more detail below: Figure 1 shows a longitudinal section through a trained as a starter device

electric machine,

FIG. 1 a shows an embodiment variant known from the prior art for the fixation of river iron and magnets by means of retaining springs,

Figure 1 b a likewise known from the prior art embodiment of the

Fixing of iron and magnets by means of two introduced into the interior of the pole housing retaining rings, Figure 2 is a perspective view of the invention proposed

annular positioning device,

Figure 3 is a side perspective view of the annular design

Positioning device according to FIG. 2,

FIG. 4 shows a lateral plan view of a hybrid part, consisting of a metallic ring and molded plastic material,

Figure 5 shows an alternative embodiment of the ring-shaped

Positioning device made of metallic ring and plastic ring,

FIG. 6 shows the perspective view of FIG. 5 as separate structural components

Components metal ring and plastic in the joined state and Figure 7 is a side plan view of the according to Figure 6 of metal ring and plastic ring annular positioning device.

variants The illustration according to FIG. 1 shows a longitudinal section of an electrical machine designed in particular as a starter device.

The starting device 10 according to FIG. 1 has, for example, a starter motor 13 and a toe-in actuator 16, which may be designed, for example, as a relay or starter relay. The starter motor 13 and the electric Vorspuraktuator 16 are fixed to a common drive end plate 19. The starter motor 13 is functionally to drive a starter pinion 22 when it is in the ring gear 25 of the not shown here

Internal combustion engine is eingespurt.

The starter motor 13 has a housing as a pole tube 28 that on its inner circumference

Pole shoes 31 carries, which are each wrapped by a field winding 34. The pole shoes 31 in turn surround an armature 37, which has an armature packet 43 constructed from fins 40 and an armature winding 49 arranged in grooves 46. The armature package 43 is pressed onto a drive shaft 44. At the Andrehritzel 22 facing away from the end

Drive shaft 13, a commutator 52 is further attached, which is constructed, inter alia, of individual commutator fins 55. The commutator bars 55 are so electrically connected in a known manner with the armature winding 49 that sets when energizing the commutator fins 55 by carbon brushes 58, a rotational movement of the armature 37 within the pole tube 28. A arranged between the electric drive and the starter motor 13 power supply 61, supplied in the on state, both the carbon brushes 58 and the field winding 34 with power. The drive shaft 13 is commutator side supported with a shaft journal 64 in a sliding bearing 67, which in turn is held stationary in a Kommutatorlagerdeckel 70. Of the

Commutator bearing cap 70 in turn is by means of tie rods 73 which can be arranged distributed over the circumference of the pole tube 28, so for example screws, for example, two three or four pieces, fixed in the drive end plate 19. It supports the pole tube 28 on the drive end plate 19 and the Kommutatorlagerdeckel 70 in turn on the pole tube 28th

Viewed in the drive direction, the armature 37 is adjoined by a sun gear 80, which is part of an epicyclic gear 83 designed, for example, as a planetary gear. The sun gear 80 is surrounded by a plurality of planet wheels 86, usually three

Planet wheels 86, which in turn are supported by means of rolling bearings 89 on journals 92. The planet wheels 86 roll within a ring gear 95, which in the pole tube 28th is stored outside. Towards the output side, the planet gears 86 are adjoined by a planet carrier 98, in which the axle journals 92 are received. Of the

Planet carrier 98 is again in an intermediate storage 101 and a therein

arranged sliding bearing 104 is stored. The intermediate bearing 101 is designed pot-shaped such that in this both the planet carrier 98 and the planet gears 86 are added. Furthermore, in the cup-shaped intermediate bearing 101, the ring gear 195 is arranged, which is ultimately closed by a cover 107 relative to the armature 37. Also, the intermediate bearing 101 is supported with its outer circumference on the inside of the pole tube 28. The armature 37 has on the end facing away from the commutator 52 end of the drive shaft 13 a further shaft journal 110, which also in a sliding bearing 113th

is included. The sliding bearing 113 in turn is in a central bore of the

Planet carrier 98 recorded. The planet carrier 98 is integrally connected to the output shaft 1 16. The output shaft 1 16 is supported with its end 119 remote from the intermediate bearing 101 in a further bearing 122 which is fixed in the drive bearing plate 1 19.

The output shaft 116 is divided into several sections: Thus, the section which is arranged in the sliding bearing 104 of the intermediate bearing 101, a section with a

Spur gear 125 (internal toothing), which is part of a shaft-hub connection 128. The shaft-hub connection 128 in this case allows the axially rectilinear sliding of a driver 131. The driver 131 is a sleeve-like extension which is integrally connected to a cup-shaped outer ring 132 of the freewheel 137. The freewheel 137, which may be, for example, a Richtgesperre, further consists of an inner ring 140 which is disposed radially within the outer ring 132. Between the inner ring 140 and the outer ring 132 clamping body 138 are arranged. The

Clamping 138 prevent in cooperation with the inner ring 140 and the

Outer ring 132 a relative rotation between the outer ring 132 and the inner ring 140 in a second direction. In other words, the freewheel 137 allows a circumferential relative movement between the inner ring 140 and the outer ring 132 in one direction only. In this embodiment, the inner ring 140 is formed integrally with the starter pinion 22 and its helical teeth 143 (external helical teeth). The starter pinion 22 may alternatively be designed as a straight toothed pinion. Instead of electromagnetically excited pole pieces 31 with excitation winding 34, permanent magnetically excited poles can also be used, ie permanent magnets 31. The electric Vorspuraktuator 16 and a linearly movable armature 168 in this also has the task, with a tension member 187 to move in the drive bearing plate 19 rotatably arranged lever 190 to move. The lever 190, which is usually designed as a fork lever, engages with two tines, not shown here, two discs 193 and 194 on its outer periphery to move a trapped between them driver ring 197 to the freewheel 137 back against the resistance of a spring 200 and thereby the Andrehritzel 22 in the sprocket 25, einzuspuren the internal combustion engine, not shown in the illustration of Figure 1. Below, the Einspurmechanismus will be discussed in more detail. The electric Vorspuraktuator 16 has a bolt 150 which represents an electrical contact and in the case of Einbausein in the vehicle at the positive terminal of an electric starter battery, which is not shown in Figure 1, is connected. The bolt 150 is passed through a lid 153. A second bolt 152 provides a connection for the electric starter motor 13, which is supplied via the power supply 61 (thick wire). The lid 153 includes a housing 156 made of steel, which is fastened to the drive end plate 19 by means of a plurality of fastening elements 159, which can be designed, for example, as screws. In the electric Vorspuraktuator 16 is a pusher 160 for exerting a tensile force on the fork lever 190 and a switching device 161 is arranged. The thrust device 160 comprises a spool 162 and the switching device 161 comprises a winding 165. The spool 162 of the thrust device 160 and the winding 165 of the switching device 161 each act in the switched-on state

electromagnetic field, which flows through various components. The shaft-hub connection 128 may instead of a spur 125 also with a

Steep thread toothing be equipped. The combinations are possible, according to which a) the starter pinion 22 is helically toothed and the shaft-hub connection 128 has a straight toothing 125, or b) the starter pinion 22 is helically toothed and the shaft-hub connection 128 has a helical thread toothing or c) the starting pinion 22 is made straight-toothed and the shaft-hub connection 128 has a helical spline.

Figure 1 a is known from the prior art mounting option for

To draw river iron and magnets within a Polgehäuses. The housing 28 shown in Figure 1a represents a pole tube of the electric machine 10. On the inside are, for example, permanent magnets 31 or pole pieces 31, the excitation windings 34, added. Between the individual magnets, according to the exploded view in FIG. 1 a, there are flux irons 200, which are arranged in the axial direction extending retaining springs 202, on the inner circumference of the housing of the electric machine. In this case, it is the pole tube 28 of the electric machine, in particular as a starter device for a

Internal combustion engine is formed. Figure 1 b shows another embodiment of the fixation of magnets or river iron on the housing of an electrical machine.

The exploded view according to FIG. 1 b shows that the housing 28 of the electrical machine, i. the pole tube the magnets 31, the stator of the electric

Represent machine, for example, by a first retaining ring 104 and a second retaining ring 206 are fixed. Between the individual circumferentially spaced apart permanent magnets or pole shoes with excitation winding, see position 31, rod-shaped configured river iron 200 are introduced. Both the

Permanent magnets or pole pieces with excitation winding and the river iron 200, are by the first retaining ring 204 and the second retaining ring 206 at the

Inner peripheral surface of the housing of the electric machine fixed.

The illustration according to FIG. 2 shows a perspective view of the annular positioning device proposed according to the invention.

An annular positioning device 208 shown in perspective in FIG. 2 can, on the one hand, compare to FIGS. 2, 3 and 4, as a hybrid component, in which a plastic encapsulation 226 surrounds a metallic insert 224. In Figures 5, 6 and 7 is an embodiment of the annular

Positioning device 208 can be seen, which is made of two separate components, namely a metal ring 228 and a plastic ring 230, which represent an assembled component, the annular positioning means 208 in the mounted state. From the perspective view according to FIG. 2, it can be seen that the annular positioning device 208 manufactured here as a hybrid component 222 has an axial support surface 210. The axial support surface 210 provides a circumferential ring, on whose

Inside the magnets 31 of the stator of the electric machine 10 abut. As a result, they are fixed in the axial direction. The individual segments of the axial support surface 210 are arranged in the circumferential direction, for example in a 60 ° -partition, compare position 216, which corresponds to the dimension of the magnets 31 in the circumferential direction. In addition, the annular positioning device 208 according to the perspective

Representation in Figure 2 axially extending axial projections 218. These in turn are on the inside, i. formed on the magnets 31 facing side, tangential support surfaces 214. In addition, the annular includes

Positioning device 208 according to the perspective view in Figure 2, a circumferential radial support surface 212, which fix the magnets 31 in their installed position in the housing 28 on the inner circumference. The inventively proposed annular positioning means 208 - here formed as a hybrid component 222 - ensures that the magnets 31 are fixed both axially and radially and beyond also in the tangential direction on the inner peripheral surface of the pole tube 28 of the electric machine 10. In addition, the axial projections 218 are provided with a recess 220. The recess 220 is approximately groove-shaped and corresponds to the geometry of the river iron 200, which are fastened between the individual magnets 31 on the inner peripheral surface of the pole tube 28.

The representation in accordance with FIG. 3 is likewise a perspective view of the ring-shaped design produced in this embodiment as a hybrid component

Remove positioning device. From the perspective top view according to FIG

3 shows that the individual axial projections 218 arranged in a 60 ° division each have a recess 220 for positioning the river iron 200. With reference numeral 210, the axial support surface is designated, reference numeral 212 denotes the

Continuously formed on the inside of the annular positioning means 208 radial support surface 212 out.

FIG. 4 shows a section through the annular positioning device.

The ring-shaped positioning device 208 shown in section in FIG. 4 is designed as a hybrid component 222, in which a metallic insert 224, that of the annular Positioning device 208 gives the necessary mechanical stability, is enclosed by a plastic extrusion 226. At the plastic extrusion 226, the axial projections 218 are formed in 60 ° pitch, corresponding to the pitch in which both the molten iron 200 and the magnets 31 are fixed to the inner circumferential surface of the housing 28.

FIGS. 5, 6 and 7 show an alternative embodiment of the annular positioning device proposed according to the invention. As FIG. 5 shows, in this case the annular positioning device 208 is made of two components. On the one hand, it is a metal ring 228, which is joined with a plastic ring 230. In the exploded view of Figure 5, the metal ring 228 is shown, on the one hand, the axial projections 218 - executed in 60 ° division -, further formed on the inside circumferential radial support surface 212 and the axial support surface 210 for permanent magnets or pole pieces 31 with excitation winding 34 of the stator of the electric machine.

With the metal ring 228 as shown in Figure 5, a plastic ring 230 is added, the tangential in the region of the axial projections 218 of the metal ring 228

Support surfaces 214 for preventing relative movement of the permanent magnets on the inner peripheral surface of the housing 28 of the electric machine 10 has.

Figure 6 shows the joined state of the two still separated in Figure 5 components metal ring 228 and plastic ring 230th

FIG. 7, in turn, shows a sectional view through the assembled, annular

Positioning device 208 as shown in Figure 6. From the illustration in Figure 7 shows that the metal ring 228 and the plastic ring 230 along abutment surfaces 234 abut each other.

With both embodiments of the inventively proposed annular positioning device 208 is achieved that on the inner peripheral surface of the particular designed as a pole tube 28 housing the electric machine 10th

Permanent magnets and river iron 200 on the one hand or on the other hand pole pieces 31 of the excitation windings 34 can be attached without them during operation of the electric Leave the machine the original installation position, so as to ensure that the starting power of the starter of the electric machine due to relative movements of river iron 200 and permanent magnets 31 decreases.

Claims

Claims 1. Electrical machine (10), in particular starter device for a

Internal combustion engine having a housing (28) in which at least one magnet (31) and at least one fluetian iron (200) are accommodated, characterized in that the at least one magnet (31) and the at least one fluetian iron (200) are provided by an annular positioning device ( 208) are held at least radially from the inside and in the circumferential direction in the housing (28).

2. Electrical machine according to claim 1, characterized in that the annular positioning device (208) is designed as a hybrid component (222) or as two separate components (228, 230) joined component.

3. Electrical machine according to one of the preceding claims, characterized

characterized in that the hybrid component (222) has a metallic insert (224) which is surrounded by a plastic extrusion (226).

4. Electrical machine according to the preceding claim, characterized in that the annular positioning means (208) axial support surfaces (210), radial support surfaces (212) and tangential support surfaces (214) for positioning the at least one magnet (31).

5. Electrical machine according to the two preceding claims, characterized

in that the annular positioning device (208) has depressions (220) for positioning the at least one flux iron (200) in the region of axial projections (218).

6. Electrical machine according to one of the preceding claims, characterized

characterized in that the annular positioning means (208) is formed as a joined member formed with the metal ring (228) on the axial projection (218).

7. Electrical machine according to one of the preceding claims, characterized in that on the metal ring (228) axial support surfaces (210), radial support surfaces (212) and tangential support surfaces (214) for the at least one magnet (31) are provided.

8. Electrical machine according to one of the preceding claims, characterized

in that the axial projections (218) of the metal ring (228) have depressions (220) for positioning the at least one flux iron (200).

Electrical machine according to one of the preceding claims, characterized in that the annular positioning device (208) in the housing (28), in particular in a pole tube is positively or non-positively attached.

Electric machine according to one of the preceding claims, characterized in that the annular positioning device (208) contact surfaces (210, 212, 214) for the axial, radial and tangential positioning of the at least one magnet (31).