AU772328B2

AU772328B2 - Electric machine with an annular gap seal

Info

Publication number: AU772328B2
Application number: AU75049/00A
Authority: AU
Inventors: Wolfgang Gottfried; Thomas Lengenfelder; Gerhard Pflueger; Erich Wolf
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1999-09-17
Filing date: 2000-08-08
Publication date: 2004-04-22
Anticipated expiration: 2020-08-08
Also published as: CN1192467C; EP1131878A1; JP4763198B2; BR0007155A; EP1131878B1; CN1321355A; DE50014423D1; RU2251778C2; DE19944557A1; WO2001022559A1; JP2003510997A; AU7504900A

Description

-1- Electric machine with an annular gap seal Prior Art The invention relates to an electric machine, in particular a generator.

A generator with an annular gap seal is known from WO 99/17430. A spacing piece between a belt pulley and a roller bearing is arranged in it in such a way that it forms an annular gap with a part secured to the hub. This annular gap has however only a limited sealing effect. This annular gap seal is only in a position to prevent larger particles from entering the area between the spacing piece and the roller bearing. The disadvantage resulting from this limited sealing effect is that the annular gap seal has no sealing effect against fluids and smaller particles.

Summary of the Invention According to the present invention there is provided an electric machine with a shaft, a hub, and an annular gap formed between, on the one hand, the shaft, or at least one first component connected to the shaft so as to rotate positively therewith, and, on the other hand, the hub, or at least one second component connected to the hub so as to rotate positively therewith; in which the annular gap is at least partially filled with a viscous substance, and the annular gap is at least partially U-shaped, with free leg-ends of a U-shaped region of the annular gap being oriented radially inwards, and o. 25 the at least one first component has a radially-outward projecting washer-shaped collar separating the free leg-ends from one another; said collar extending into a recess in the hub or in the at least one second component, and the hub is mounted, by means of at least one rolling-bearing, so as to be rotatable relative to the shaft; wherein the at least one rolling-bearing has at least one sealing-ring, oriented radially, which partially bounds the U-shaped region of the annular gap.

o Advantages of the invention It is possible with the electric machine of the invention to form the annular gap seal in such a way that it seals against fluids and smaller particles. The improved annular gap seal 26/02/04,eh 2023.spc,1 -2protects the roller bearing already sealed with seals and therefore against the damaging influence of fluids. This is particularly an advantage when the vehicle, which has the electric machine of the invention, must also have a so-called wadding ability and therefore be able to be driven through flooded areas.

Brief Description of the Drawings The invention will be described in the following in an embodiment on the basis of the accompanying drawings. Figure 1 shows a longitudinal section through the electric machine of the invention, a rotor of the machine appearing in section and, in the lower half of the picture, the rotor being shown in a side view; Figure 2 shows a section through an annular gap seal according to the invention.

Identical components or components operating identically are shown with the same identifying numbers.

Detailed Description of the preferred embodiment Figure 1 shows in the upper half of the picture a longitudinal section through the electric machine of the invention. The electric machine, here in the form of a generator, has a potshaped housing 10, which is closed by means of a housing cover 14. A stator is secured inside the pot-shaped housing 10, which surrounds a rotor 22. The rotor 22 is positioned on the one hand above a bearing 26 in the base of the housing 30 and on the other above a roller bearing 34 in the housing cover 14. The roller bearing 34 supports itself with a :o 25 bearing ring on the side of the bearing 38 on a rotor shaft 42. On the side of the hub the .i roller bearing 34 supports itself above a bearing ring 46 on the side of the hub in the housing cover 14, the housing cover 14 forming a hub 54 with a shoulder 50. The axial position of the bearing ring 38 on the side of the shaft is limited by means of a shaft collar 57 on which the bearing ring 38 on the shaft side is secured by means of a nut 60 above a flange 63 of a belt pulley 66 and a first component arranged between a flange 63 and .bearing ring 38. The first *oe* 26/02/04,eh I 2023.spc,2 IWO 01/22559 PCT/DEOO/02635 3 component 69 is rotationally fixed to the shaft 42. On the hub side a covering cap 72 covers an electric switch 75, which is arranged outside the shoulder 50. A second component 78, which lies on the bearing ring 46 on the machine side is secured to the covering cap 72. The covering cap 72 and the second component 78 are both rotationally fixed to the housing cover 14 and therefore to the hub 54. Between the shaft 42 or the first component 69 rotationally fixed to the shaft 42 and the second component 78 rotationally fixed to the hub 54 an annular gap 81 is formed.

The annular gap 81 and the area surrounding it is illustrated in Figure 2. As can be clearly seen, the annular gap 81 is at least partially filled with a pasty material 84.

This pasty material 84 is, in particular, grease. The annular gap 81 is at least partially U-shaped. The U-shaped area 87 of the annular gap 81 has free leg ends 90, 91, which are directed inwardly radial to the shaft 42. Both the free leg ends 90, 91 of the U-shaped area 87 are separated from one another by a washer-shaped collar 93. The washer-shaped collar 93 is formed on the first component 69 in one piece and protrudes radially to the outside. The washer-shaped collar 93 runs into a recess 96 of the hub 54 or to the second component connected to the covering cap. The hub 54 is rotatably positioned through the roller bearing 34 opposite the shaft 42. The roller bearing 34 has an outwardly extending seal 99, which partially borders the U-shaped area 87 of the annular gap 81. It is preferred if the washer-shaped collar 93 is formed on the first component 69 and the first component 69 serves as a spacing ring 102 for the bearer ring 38 of the roller bearing 34 on the shaft side. It is also preferred if the recess 96 is arranged in the covering cap 72 formed from the first component 78.

If the electric machine depicted in Figure 1 is driven by means of the belt pulley 66, then the washer-shaped collar 93 rotates in the recess 96 of the second component 78.

If, as described previously, the pasty material 84, for example grease, is brought into the annular gap, the pasty material 84 will be forced radially to the outer area through the friction on the washer-shaped collar 93 and the angular velocity of the collar 93.

This results in the pasty material 84 collecting in the U-shaped area 87, notably in the outer areas. Depending on the quantity of pasty material 84 placed in the annular gap 81, the U-shaped area 87 is more or less full. In a maximal filling both free legs of WO 01/22559 PCT/DEOO/02635 4 the U-shaped area 87 are filled. By this means the connection between the roller bearing 34 and the surrounding area is flushly sealed. So that the sealing effect in the filled annular gap 81 remains constant under water pressure, the pasty material 84 is to be selected so that it has, on the one hand a good adhesion both on the second component 78 and on the first component 69 and on the other holds together well internally. A good coordination of the qualities of these materials has the advantage that water pressing on the annular gap seal at least in the case of light pressure cannot enter behind the washer-shaped collar 93 on the bearing side.

Claims

1. An electric machine with a shaft, a hub, and an annular gap formed between, on the one hand, the shaft, or at least one first component connected to the shaft so as to rotate positively therewith, and, on the other hand, the hub, or at least one second component connected to the hub so as to rotate positively therewith; in which the annular gap is at least partially filled with a viscous substance, and the annular gap is at least partially U-shaped, with free leg-ends of a U-shaped region of the annular gap being oriented radially inwards, and the at least one first component has a radially-outward projecting washer-shaped collar separating the free leg-ends from one another; said collar extending into a recess in the hub or in the at least one second component, and the hub is mounted, by means of at least one rolling-bearing, so as to be rotatable relative to the shaft; wherein the at least one rolling-bearing has at least one sealing-ring, oriented radially, which partially bounds the U-shaped region of the annular gap.

2. The electric machine as claimed in claim 1, wherein the collar is formed on the at least one first component, which serves as a spacing-ring for a bearing-ring of the at least one rolling-bearing, said bearing-ring being on the shaft side of the at least one "rolling-bearing. ia

3. The electric machine as claimed in claim 2, wherein the recess is arranged in a covering-cap formed by the at least one second component. S

4. The electric machine as claimed in claim 3, wherein the covering-cap serves for axially securing a bearing-ring of the at least one rolling-bearing, said bearing- ring being on the hub side of the at least one rolling-bearing.

5. The electric machine as claimed in any one of the preceding claims, wherein said electric machine is a generator.

6. The electric machine as claimed in any one of the preceding claims, wherein the viscous substance is grease. 26/02/04,eh 1 2023.spc,5 -6-

7. An electric machine, substantially as hereinbefore described with reference to the accompanying drawings. Dated this 2 6 th day of February, 2004 ROBERT BOSCH GMBH By Their Patent Attorneys CALLINAN LAWRIE 26/02/04,eh 2023.spc,6