GB2240585A

GB2240585A - Swivel mounting for electric machines

Info

Publication number: GB2240585A
Application number: GB9027861A
Authority: GB
Inventors: Francesco Riccetti; Klaus-Georg Buerger
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1989-12-29
Filing date: 1990-12-21
Publication date: 1991-08-07
Anticipated expiration: 2010-12-21
Also published as: JPH0733573Y2; JPH0394058U; IT9022236V0; IT9022236U1; IT220423Z2; GB9027861D0; FR2656748B3; GB2240585B; FR2656748A3; DE8915249U1

Abstract

A swivel mounting for electric machines, e.g. generators (10) of motor vehicles, has two bearing eyes (12, 13) spaced apart one behind the other on the machine housing, between which a bearing holder (11) on the engine housing and a bearing pin (17) is screwed into an axially displaceable threaded bushing (18) in the rear bearing eye (13). In order to make the engagement of the bushing (18) in the eye (13) resistant to shaking and temperature, the bushing is provided with a longitudinal through slot (21), and is fastened in the bearing eye (13) by spreading forces. The bushing may also be keyed against rotation in the eye. <IMAGE>

Description

DESCRIPTION "IMPROVEMENTS FOR ELECTRIC MACHINES" The present invention relates to an electrical machine with a swivel mounting for a generator which enables the belt tension of the generator to be adjusted.

It is already known from WO 82/03735 to provide in a swivel bearing for vehicle generators two bearing eyes which are spaced apart one behind the other on the housing of the generator, between which there engages a bearing holder, having a bearing bore, which holder is formed on the motor drive. A bearing pin, which is in the form of a screw, is pushed through the front bearing eye and through the bearing bore of the holder and is screwed into a threaded bushing in the rear bearing eye. The threaded bushing is axially displaceable in its bearing eye in order to compensate for play between the bearing holder and the rear, Bside bearing eye of the double swivel arm.

However, this solution is disadvantageous in that, because the threaded bushing is inserted loosely into the bearing eye, in the course of time the threaded bushing can be dislocated by shaking and temperature stresses, which can cause an unstable bearing and possibly detachment of the bearing pin from the bushing.

Furthermore, it is known from DE-OS 27 49 196 to counteract the detachment of a nut from a complementarily threaded bolt which has been screwed onto the nut by providing the nut with a longitudinal slot, such that, when the threaded bolt is screwed onto the nut, the slot widens somewhat to allow the nut to be tightly fitted on the threaded bolt. A locking ring is also provided, which is seated on a cylindrical projection of the nut and which is intended to protect the nut against rotation when the nut has been screwed onto the bolt. However, this solution is not suitable for use in a swivel mounting for a generator machine because of the clearance between the swivel arms and the bearing holder of the swivel mounting, which has to be compensated axially.

The present invention provides an electrical machine having first'and second bearing eyes spaced apart one behind the other on the housing of the electrical machine for the swivel mounting of the machine on a holder, which engages between the bearing eyes and is provided with a bearing bore, and a bearing pin in the form of a threaded screw, wherein the first bearing eye is provided with an axially displaceable threaded bushing which is provided with a means for preventing rotation and with a longitudinal through slot, and is fastened in the bearing eye by spreading forces.

The present invention has the advantage that the threaded bushing can be securably inserted into the first bearing eye when the electrical machine is assembled. It enables the pivot bearing to remain in position even when the apparatus is subjected to shaking or to temperature stresses. Moreover, by virtue of the said axial displaceability, a defined abutment of the bearing eyes against the holder is ensured. In addition to simplified assembly, the present invention also prevents the threaded bushing falling out of the second bearing eye and being lost prior to full assembly.

Preferably, part of the threaded bushing has an unthreaded part which forms a bearing for the bearing pin.

This feature avoids the need for a two-part assembly comprising a bearing which is distinct from the threaded bushing and a separate nut.

Preferably, the part of the threaded bushing comprises a collar of non-circular outer cross-section which engages with a complementary counter-sunk region of the first bearing eye so as to prevent rotation of the bushing relative to the first bearing eye. For example, the collar may comprise one or more flattened surfaces on its outer perimeter which functions to prevent rotation of the bushing relative to the first bearing eye.

The present invention can be used for example, to provide a swivel mounting for motor vehicles.

The present invention will now be described by way of illustration only, with reference to the accompanying drawings, wherein: Fig. 1 illustrates an electrical machine of the present invention and shows two bearing arms of a generator between which an intermediate pivot holder is connected by a bearing pin, and Fig. 2 is an enlarged representation of a front view of the rear bearing eye of the generator shown in Fig. 1, with a threaded bushing inserted.

Referring to Fig. 1, a generator 10 for a motor vehicle is pivotally fastened by means of two swivel arms on a holder 11 which is formed on the propulsion unit (not shown) of the motor vehicle. The two swivel arms have respective bearing eyes 12, 13, which are spaced apart one behind the other and which are formed on the end shield 14 at the drive end of the generator and the end shield 15 at the brush end, of the generator 10. The holder 11 engages between the bearing eyes 12 and 13, and has a bearing bore 16. A bearing pin 17 is inserted into the bearing eyes 12, 13 and the bearing bore 16, and is in the form of a screw. The rear bearing eye 13 on the B end shield 15 is provided with an axially displaceable threaded bushing 18, into which the bearing pin 17 is screwed by its thread 19.On the side of the A end shield 14 lying opposite the front bearing eye 12 there is formed a further bearing eye 20, by means of which the generator 10 is screwed fast to a support (not shown) in the motor vehicle following tensioning of the driving belt (not shown).

In order to fasten the threaded bushing 18 in the rear bearing eye 13 in a simple manner such that it is not rotatable relative to the rear bearing eye, the threaded bushing 18 is provided with a longitudinal through slot 21, which on insertion of the threaded bushing 18 into the bearing eye 13, is first closed up and subsequently resiliently opened out so that the threaded bushing 18 is fastened in the bearing eye 13 in a positive manner by spreading forces. To enable take up of the axial clearance 22 between the holder 11 and the bearing eyes 12 and 13, the threaded bushing 18 is also axially displacable during tightening of the bearing pin 17 notwithstanding the effect of the spreading forces. Furthermore, clamping of the threaded bushing 18 in the bearing eye 13 can be further enhanced, upon the screwing-in of the bearing pin 17, if the screw thread is appropriately dimensioned.

A bearing pin 17 having a relatively short thread length and correspondingly long bearing length can be used in that the threaded bushing 18 is extended in its front part to form a bearing bushing 23 for the bearing pin 17. As shown in Fig. 2, the front region of the threaded bushing 18, which is extended to form the bearing bushing 23, is provided with a collar 24, which has on the outside two flattened regions 25 which lie opposite one another. To prevent rotation of this collar 24 relative to the bearing eye, its flattened regions 25 engage in a correspondingly designed counter sunk region 26 in the bearing eye 13.

As a means of preventing relative rotation, the threaded bushing could also be inserted on the outside and could also leave a hexagonal, eccentric, or similar asymmetrical portion, which is received in a corresponding recess in the bearing eye 13.

By insertion and screwing of the bearing pin 17 into the threaded bushing 18, the holder 11 is clamped in both directions between the bearing eyes 12 and 13, the threaded bushing 18 abutting against the holder 11 by an end face and ensuring a seat in the B end shield 15 which is resistant to shaking and temperature.

Claims

1. An electrical machine having first and second bearing eyes spaced apart one behind the other on the housing of the electrical machine for the swivel mounting of the machine on a holder, which engages between the bearing eyes and is provided with a bearing bore, and a bearing pin in the form of a threaded screw, wherein the first bearing eye is provided with an axially displaceable threaded bushing which is provided with a means for preventing rotation and with a longitudinal through slot, and is fastened in the bearing eye by spreading forces.

2. A machine as claimed in claim 1, wherein the threaded bushing has an unthreaded part which forms a bearing for the bearing pin.

3. A machine as claimed in claim 2, wherein the unthreaded part of the threaded bushing comprises a collar of non-circular outer cross-section which engages with a complementary counter-sunk region of the first bearing eye so as to prevent rotation of the bushing relative to the first bearing eye.

4. A machine according to claim 3 wherein the collar has at least two flattened surfaces on its outer perimeter.

5. A machine constructed substantially as described herein with reference to the accompanying drawings.