GB2053581A

GB2053581A - Mounting device for an electric machine

Info

Publication number: GB2053581A
Application number: GB8020194A
Authority: GB
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1979-06-22
Filing date: 1980-06-20
Publication date: 1981-02-04
Also published as: ES492641A0; JPS566641A; ES8103513A1; DE2925141A1; FR2460062A1; FR2460062B3

Abstract

A device for adjustably mounting an electrical machine (41) on a mounting face (42) comprises a saddle-shaped support (43) and an intermediate wedging member (44) which is inserted between the machine and the saddle-shaped support. The intermediate member serves to vary the position of the machine shaft relative to the mounting face (42) and particularly to tension the V-belt which drives the machine. The mounting device is used especially for generators for motor vehicles. <IMAGE>

Description

SPECIFICATION Mounting device for an electric machine The invention relates to a mounting device for adjustably mounting an electrical machine.

Three-phase generators in motor vehicles are driven by the engine, generally by way of a V-belt.

In addition to driving the generator, the crankshaft of the engine usually drives a further unit such as the water pump or the radiator fan. The driving Vbelt must have a predetermined tension, that is to say, it must not be seated too loosely or too tightly. For this reason, the generators are frequently equipped with a retaining arm and a pivoted arm. The generators are pivoted about the pivoted arm to adjust the tension of the belt.

When the tension of the belt has been set, it is maintained by locking the retaining arm.

The three-phase generator in a motor vehicle is subjected to high vibratory stresses during operation. In order to reduce the vibratory stress, attempts have already been made to mount the generator on a saddle-shaped support. However, this has the disadvantage that is difficult to tension the V-belt.

The present invention resides in a mounting device for an electrical machine, comprising a saddle-shaped support adapted to be mounted on a mounting face, and an intermediate member which is inserted between the machine and the saddle-shaped support, the effective thickness of the intermediate member varying from one end to its other end in accordance with a rising or descending function.

This has the advantage that the tension of the belt is adjustable even though the machine is mounted in a saddle-shaped support. Thus, it is also possible to use saddle-shaped supports in cases in which this was hitherto impossible. The vibratory stress on the machine is reduced by mounting the machine in a saddle. Cooling of the machine can be improved by arranging the saddleshaped support so as to be pivotable.

Preferably an external face or portion of the intermediate member abuts an internal cylindrical face of the saddle-shaped support and an internal face or portion of the intermediate member abuts an external cylindrical face of the machine. A stable construction of the intermediate member, by means of which the tension of the belt is adjusted, is thus advantageously obtained. A construction of the intermediate member as a circular hollow cylinder having ribs is advantageous with respect to saving material, and thus to saving weight, and with respect to a further improvement in cooling.

The invention is further described, by way of example, with reference to the drawings, in which: Figure 1 is a cross section through a generator which is to be mounted in a saddle-shaped support.

Figure 2 shows a first embodiment of the mounting device, and Figure 3 shows a second embodiment of the mounting device.

The housing of a three-phase generator shown in Fig. 1 comprises a housing shell 11 having an external circumference 12 of circular cross section. A first bearing plate 14 at the drive end and a second bearing plate 1 5 are secured to the housing casing 11. Bearings 1 6 and 17 for journalling a machine shaft 18 are fitted in the two bearing plates 14 and 1 5. A stator 19 having a stator winding 21 is pressed into the -housing shell 11. The output of the stator winding 21 is connected to a rectifier which comprises rectifier diodes 22 which are fitted in the second bearing plate 1 5. A fan wheel 23 and a belt pulley 24 are secured to the drive end of the machine shaft 1 8 by means of a nut 25.The machine shaft 18 carries a rotor having a pole core 26, pole wheels 27 and an excitation winding 28. The ends of the excitation winding 28 are connected to slip-rings 29 which are also mounted on the machine shaft 1 8. The slip-rings 29 are operatively connected to carbon brushes 31 which are guided in a brushholder 32. The brush-holder 32 is connected to a voltage regulator 33. The electrical parts of the electric machine are protected against dirt and damage by a covering hood 34. The bearings 16, 1 7 are fitted in bearing bushes 35, 36 which are component parts of the respective bearing plates 14, 15. Openings 37, 38 in the bearing plates 14, 1 5 serve to ventilate the machine.

The generator 41 shown in detail in Figure 1 is indicated in Figure 2. A saddle-shaped support 43 is secured to a mounting face 42. An intermediate member 44 is located in the saddle-shaped support 43. Like the external circumference of the generator 41 , the internal circumference of the saddle-shaped support 43 is of circular cylindrical configuration. The intermediate member 44 has a crescent-shaped cross section, and the external circumference and the internal circumference of the intermediate member 44 are also of circular cylindrical configuration, the radius of the external circumference of the intermediate member 44 being equal to the radius of the internal circumference of the saddle-shaped support 43, and the radius of the internal circumference of the intermediate member 44 being equal to the radius of the external circumference of the generator 41.

In the embodiment of Figure 2, the intermediate member 44 is a wedge. The generator 41 is secured to the saddle-shaped support 43 by means of, for example, a clamping band or strap 45. The generator 41 is thereby adjustably eccentrically mounted in the saddle-shaped support 43.

The distance between the axis of the shaft 1 8 of the machine 41 and the surface of the mounting face 42 is increased according to the extent to which the wedge 44 is inserted between the generator 41 and the saddle-shaped support 43. It is thus possible to tension the V-belt of the machine 41 which runs on the V-belt pulley-24.

In Figure 3, in which the components which are the same as those of Figure 2 are provided with the same reference numerals, the intermediate member 44 is in the form of a circular hollow cylinder having ribs 46. It will be appreciated that, alternatively, the circular hollow cylinder can be of solid construction and would then have a varying wall thickness. What has been said with reference to the first embodiment correspondingly applies to the geometrical relationship. In the second embodiment shown in Figure 3, the ribs 46 are directed towards the axis of the shaft 1 8 of the machine 41 and thus reliably support the machine. In order to compensate for tolerances, the intermediate member 44 in the form of a circular hollow cylinder incorporate a slot 48. The clamping strap 45 tends to lose the slot and presses the ribs 45 against the housing 12 of the machine 41.

The intermediate member 44 can be turned in the saddle-shaped support 43 when the clamping strap 45 is loosened. The position of the axis of the shaft 18 of the machine 41 is thus also changed relative to the surface of the mounting face 42. In this manner, it is possible to tension the belt which runs on the belt pulley 24 and which drives the machine 41.

Claims

1. A mounting device for an electrical machine comprising a saddle-shaped support adapted to be mounted on a mounting face, and an intermediate member which is inserted between the machine and the saddle-shaped support, the effective thickness of the intermediate member varying from one end to its other end in accordance with a rising or descending function.

2. A mounting device as claimed in claim 1, in which the machine has a circular cylindrical external circumference and the saddle-shaped support has a circular cylindrical internal circumference, and in which one side of the intermediate member abuts snugly against the internal circumferential face of the saddle-shaped support, and the side of the support opposite the said first side abuts snugly against the external circumferential face of the machine.

3. A mounting device as claimed in claim 2, in which the intermediate member is a solid wedge.

4. A mounting device as claimed in claim 2, in which the intermediate member is a circular hollow cylinder having a wall thickness which varies over its radial circumference in the form of a sinusoidal halfwave in accordance with the difference between its predetermined external circumference and its predetermined internal circumference.

5. A mounting device as claimed in claim 2, in which the intermediate member is a circular hollow cylinder on the inner wall of which are disposed ribs whose height varies over its radial circumference in the form of a sinusoidal halfwave in accordance with the difference between the predetermined external circumferential line and the predetermined internal circumferential line.

6. A mounting device as claimed in claim 5, in which the ribs are directed towards the longitudinal axis of the machine shaft.

7. A mounting device as claimed in any of claims 2 to 6, in which the machine is held in the saddle-shaped support with the intermediate member sandwiched therebetween by means of a strap.

8. A mounting device for an electrical machine, constructed substantially as herein described with reference to and as illustrated in the drawings.