WO2010149526A2

WO2010149526A2 - Commutator bearing

Info

Publication number: WO2010149526A2
Application number: PCT/EP2010/058348
Authority: WO
Inventors: Thomas Botzenhard; Rainer Stoeckl
Original assignee: Robert Bosch Gmbh
Priority date: 2009-06-23
Filing date: 2010-06-15
Publication date: 2010-12-29
Also published as: DE102009027092A1; WO2010149526A3

Abstract

The invention relates to an electrical machine (10), in particular a starter device for a combustion engine. The electrical machine (10) comprises a housing (12), in which an armature shaft (16) is mounted. The armature shaft (16) is mounting in a bearing cover (14, 50). A bearing pin (36) receives the bearing (18), wherein the bearing pin (36) can be adjusted in order to adjust the axial clearance of the armature shaft (16).

Description

description

Title commutator bearing

State of the art

DE 42 13 819 A1 relates to the automatic adjustment of the holder of a shaft. A pressure piece engages on one side with a shaft, on the other side of the pressure piece, a shoulder protrudes from the pressure piece. A housing po- sitions and holds a lid that receives the pressure piece so that it has some axial freedom of movement. The shoulder of the pressure piece is formed slightly larger than the thickness of the lid, so that the axial play is defined exactly defined. A radial freedom of movement of the pressure piece in the housing space is produced in that the pressure piece diameter is smaller than the inner diameter of the housing space. A sealing ring around the pressure piece cooperates with the housing wall and forms a fulcrum. There is a lid with an opening provided for receiving the shoulder at the end of the pressure piece, wherein a recess at the shoulder by a predetermined distance is greater than the diameter of the lid to automatically create a free space. A housing with an axial cavity, with the inner diameter of which the position of the cover is determined, allows axial displacement of the pressure piece to create an axial clearance at the end of the shaft.

DE 1 944 721 A1 relates to a starter. The starter comprises a housing and a starter generating a magnetic flux in the electric motor and a rotor rotatable on a shaft. Axially outside the rotor, the shaft has a grooved portion and a smooth portion of smaller diameter, on the latter axially displaceably a drive pinion is guided. The output pinion is enclosed by a partially sleeve-shaped driver, which is arranged longitudinally displaceable on the shaft, and is driven by the latter by means of grooves in the circumferential direction, which have the same pitch as the grooves of the grooved Section of the shaft. The shaft is housed on both sides in the housing of the starter in plain bearings.

For starting internal combustion engines are today mainly mechanical see commutated DC motors, which serve as a starter, are used. Of the

Power is introduced through carbon brushes via the commutator in the armature winding. The anchor is currently stored in series variants in two sintered bushings. An armature shaft is usually stored today on the commutator bearing side in an oil-soaked sintered bush, which is accommodated in the commutator cover. The anchor and its longitudinal play become over an axial guidance, which leads to

Example as a recess in the armature shaft comprises a retaining washer, a shim, a cap or the like, held in the commutator. As a result, the installation space, or the resulting length of the starter in the motor vehicle is limited. Due to the large number of components, the number of required assembly steps is very high and is accompanied by a high error rate during assembly. The anchor longitudinal play is dependent on the tolerances of the plurality of components to be installed. The anchor longitudinal play has the following disadvantages with respect to the starter. First of all, a strong noise development can occur due to an impermissibly high armature longitudinal play. Furthermore, a very high shaking load of the starter occurs, which adversely affects its service life. It is also likely a reduction in life due to increased wear in relation to the carbon brushes and the sintered bushing, which may have, for example, a frequent replacement of carbon brushes.

Disclosure of the invention

According to the invention, it is proposed to manufacture a commutator bearing cover of an electrical machine, for example made of aluminum material, for example by means of aluminum diecasting, or as a stamped bent part, with a pressed-in bearing bolt being pressed into the commutator bearing cover for adjusting the axial play. A sintered bearing is pressed into the armature shaft of the electric machine. The armature longitudinal play of the armature of the electric machine is set between the drive shaft, the armature shaft and the bearing pin. The bearing pin is inserted into the commutator bearing cover, for example pressed in, and the axial stop, for example, set as a separate ball or ball shape on the drive shaft in point or line support. After adjusting the armature longitudinal play between the drive shaft, the armature shaft and the bearing pin of the bearing pin in the Kommutatorlagerdeckel joined, which can be done for example by pressing or stamping. A cap, which is applied from the outside to the Kommutatorlagerdeckel, for example, be made of plastic, designed as a stamped and bent part and fixed to the outside of the commutator bearing cap by pressing, stamping or Verklipsen.

Compared to solutions of the prior art thus reduces the storage for the armature shaft shorter; Furthermore, the puncture on the armature shaft, on which a retaining washer or a shim is arranged, as well as the outwardly bulging de cap, with the Kommutatorlagerdeckel according to the solutions of the prior art is currently closed.

In a further advantageous embodiment, the commutator bearing cover can be formed as a stamped and bent part and without cap, for the case that the bearing pin is pressed or embossed, for example, in the corresponding opening of the formed as a stamped bent part Kommutatorlagerdeckels. In this embodiment, the closure cap, which is required according to the above first embodiment, can be saved. Compared to the above-outlined first variant of the solution proposed according to the invention, a relatively short-length bearing pin is produced, which at the same time serves as a seal of the interior of the electrical machine by pressing and stamping in the corresponding opening of the commutator bearing cap.

The solution proposed according to the invention allows a considerable reduction of the individual parts in relation to a housing mounting of the armature shaft of an electrical machine, furthermore simpler and less assembly steps requiring mounting of the commutator bearing cover, which can be manufactured both as an aluminum die-cast part and as a stamped and bent part. Due to the planar design of the front side of the electric machine, which serves in particular as a starter for an internal combustion engine, can shorten the installation length and thus provide better handling during installation in view of the available scarce space on the motor vehicle. By the proposed solution according to the invention, the longitudinal play of the armature shaft can be minimized or predefined define this anchor longitudinal play. The bellied cap in the known from the prior art solutions can by a plane from

Plastic material manufactured cap to be replaced, which is either pressed into the corresponding opening for the bearing pin in the commutator bearing cap, there clipped or can be imprinted there. Due to the reduction of the defined setting of the anchor longitudinal play, the shaking load of the electric machine can be drastically reduced, combined with an increase in the service life by minimizing the wear of the carbon brushes on the commutator.

Brief description of the drawings

With reference to the drawings, the invention will be described in more detail below.

It shows:

FIG. 1 shows a bearing, known from the prior art, of an armature shaft of an electrical machine in a commutator bearing cover;

Figure 2 shows a first embodiment of the inventively proposed storage of the armature shaft in Kommutatorlagerdeckel and

Figure 3 shows a further embodiment of the present invention proposed storage of an armature shaft an electric machine in Kommutatorlagerdeckel - shown here without cap.

Figure 1 shows a bearing of an armature shaft in an electrical machine according to the prior art.

The illustration according to FIG. 1 shows that an electrical machine 10 comprises a housing 12. The housing 12 of the electric machine 10 is connected via a

Commutator bearing cap 14 closed. In this, an armature shaft 16 is mounted, on which, for example, an oil-impregnated sintered bearing 18 is formed. An axial fixing 20 of the armature shaft 16 with respect to the bearing 18 is represented by a retaining washer 22, which engages in a circumferential groove 24 in the lateral surface of the armature shaft 16. The bearing 18, the retaining washer 22 of the axial fixing 20 and the stub shaft of the armature shaft 16 are protected by a cap 26 to the outside, which protrudes by a projection 28 on the plane side of the electric machine 10 - -

is trained. With regard to the installation of the electric machine 10, this variant of the bearing of the armature shaft 16 known from the prior art requires a larger installation space, which is ultimately due to the fact that the armature shaft 16 together with its mounting in the commutator bearing cover 14 via the protrusion 28 on the otherwise plan trained end face of the commutator bearing cover 14 protrudes.

variants

FIG. 2 shows a first embodiment of the proposed invention

Solution of the armature shaft in the commutator bearing cover of the electric machine.

The illustration according to FIG. 2 shows that the electrical machine 10 shown there comprises the housing 12, which is closed by the commutator cover 14. In contrast to the commutator bearing cap 14 according to the

Embodiment variant in Figure 1, the commutator bearing cap 14 according to the invention solution is substantially planar. In particular, the closure cap 26 is formed flat and is not about the protrusion dimension 28 shown in Figure 1 raised above the plan formed end face of the commutator bearing cover 14. This shortens the installation length of the electric machine 10 of the proposed solution according to the invention by decisive millimeters, which facilitates their handling. FIG. 2 shows that the armature shaft 16 shown there comprises a bearing 18, which is preferably an oil-impregnated sintered bearing 18. The bearing 18 is embedded in an end face of the armature shaft 16. On the armature shaft 16, a sun gear 46 of a planetary gear 40 is arranged, which has a number of

Includes planetary gears 48 which mesh with a ring gear on the housing inner side of the housing 12. The armature shaft 16 as shown in Figure 2 is driven by a drive shaft 30. In the drive shaft 30, a first axial stop 32 is inserted, which may be formed as a separate spherical member, or is formed in a spherical shape. This first axial stop 32 serves to adjust the

Anchor longitudinal play, ie the axial play of the armature shaft 16, which is mounted on its side opposite the first axial stop 32 side in a bearing pin 36. The bearing pin 36 is preferably pressed into the Kommutatorlagerdeckel 14 under precise specification of the axial play, there embossed or joined in another, a Festsitz-capable manner, in a corresponding opening of the commutator bearing cap 14. Between the example in Figure 2 as a ball formed first Axialan- shock 32 and formed on a bearing pin 36 as a rounded end face second axial stop 34, the axial play of the armature shaft 16 is set accurately.

The commutator bearing cover 14 of the electric machine according to the embodiment in FIG. 2 is preferably designed as an aluminum die cast component or else as a stamped and bent component. The required geometries, in particular the stiffening in the region in which the bearing pin 36 is received, can be easily generated by these manufacturing methods. The commutator bearing cover 14 covers a brush holder 38, in which a number of carbon brushes are mounted, via which individual regions of a rotor winding 44, which is accommodated on the armature shaft 16, are supplied with current at the commutator. The rotor winding 44 of the electric machine 10 as shown in Figure 2 is surrounded by a stator winding 42 on the inside of the tubular housing 12.

While the bearing 18 preferably designed as a rear bearing can be shrunk into the end face of the armature shaft 16 opposite the commutator bearing cover 14, the bearing pin 36 is fastened in the axial direction by press fit or by embossing in the central opening of the commutator bearing cover 14. The armature longitudinal play of the armature shaft 16 is set between the drive shaft 30, the armature shaft 16 and the bearing pin 36. The bearing pin 36 is joined to the commutator bearing cap 14 and mounted with respect to the first axial stop 32, which may be formed as a separate spherical member or may be formed in spherical shape, forming the exact anchor longitudinal play. The result is a linear contact between the end face of the armature shaft 16 opposite the bearing pin 36 and the first axial stop 32 in spherical form. By point or line support, the friction between the first axial stop 32 and the opposite thereto corresponding, for example, rounded designed end face of the armature shaft is lowered. Thereafter, the pressing or embossing of the bearing pin 36 in the corresponding opening, which is in the commutator bearing cap 14, be it as an aluminum die-cast part, this is made as a stamped and bent part. A closure cap 26, which may preferably be made of plastic, or may also be formed as a stamped bent part is pressed into the corresponding opening, the rear end face of the bearing pin 36, pressed into the Kommutatorlagerdeckel 14, clipped, or fixed in any other way , The illustration according to FIG. 3 shows a further embodiment variant of the solution proposed according to the invention, in which the commutator bearing cover 14 is manufactured as a stamped and bent part of a simple geometry.

As FIG. 3 shows, a commutator bearing cover 50 also closes off the housing 12 of the electric machine 10 in contrast to the illustration according to FIG. 2. The commutator bearing cover illustrated in FIG. 3 is designed as a stamped and bent part 50 in a simplified geometry. In particular, the commutator bearing cover comprises, as a stamped bent part 50, an opening 54 which is delimited by a peripheral 56. The bearing pin 36 according to the further embodiment variant shown in Figure 3 has a stummeiförmig trained end, wherein the plan side, which is enclosed by the border 36 of the opening 54, the commutator bearing cover as a stamped and bent part 50 closes to the outside. Hidden by the commutator blades to be contacted, the bearing is not shown, extending in the axial direction parallel to the axis 52 extending portion of the bearing pin 36

18, which, analogously to the representation according to FIG. 2, may be an oil-impregnated sintered bearing pressed or shrunk into the armature shaft 16. The commutator bars of the commutator in the embodiment according to FIG. 3 cover the second axial stop 34 on which the armature shaft 16, cf. Figure 2, assigning end of the bearing pin 36 is formed. Between the first axial stop 32, not shown in FIG. 3, and the second axial stop 34 formed on the bearing pin 36, the axial play of the armature shaft 16 is adjusted analogously to the embodiment variant according to FIG.

The plan side of the bearing pin 36 can be covered over the closure cap 26 shown in Figure 2, manufactured as a plastic material or manufactured as a stamped and bent part. This can also be dispensed with, since the interior of the housing 12 takes over the sealing of the interior of the housing 12 when the bearing bolt 36 is pressed into the border 56 of the opening 54.

Claims

- o ■ claims

1. Electrical machine (10), in particular starting device for an internal combustion engine, with an in a housing (12) mounted armature shaft (16) and a bearing cap (14, 50), characterized in that the bearing pin (36) the bearing (18) receives, and with the bearing pin (36) the axial play of the

Armature shaft (16) is adjustable.

2. Electrical machine according to claim 1, characterized in that the bearing (18) is formed as a sintered bearing, which is received in the armature shaft (16).

3. Electrical machine according to claim 1, characterized in that the bearing cap (14) is a Kommutatorlagerdeckel, in which the bearing pin (36) pressed, embossed, clipped or caulked.

4. Electrical machine according to claim 1, characterized in that the bearing cap (14) is made of aluminum or designed as a stamped and bent part.

5. Electrical machine according to claim 1, characterized in that the axial play of the armature shaft (16) between the bearing pin (36) and a first axial stop (32) of a drive shaft (30) is set.

6. Electrical machine according to claim 1, characterized in that the longitudinal clearance of the armature shaft (16) between a first axial stop (32), a drive shaft (30) and a second axial stop (34) which is executed on the bearing pin (36) adjusted is.

7. Electrical machine according to claims 5 or 6, characterized in that the first axial stop (32) is designed as a ball or in spherical form.

8. Electrical machine according to claims 5 or 6, characterized in that between the first axial stop (32) of the drive shaft (30) and the armature shaft (16) is present point or line contact.

9. Electrical machine according to claim 1, characterized in that an opening (54) in the bearing cap (14, 50) by a flat closure cap (26) which is made either of plastic material or as a stamped and bent part is closed.

10. Electrical machine according to claim 9, characterized in that the closure cap (26) in the opening (54) of the commutator bearing cover (50) is pressed, embossed or clipped.

1 1. Use of the electric machine (10) according to one or more of the preceding claims as starting device for an internal combustion engine.