GB2235822A

GB2235822A - A rectifier assembly for motor vehicle alternators

Info

Publication number: GB2235822A
Application number: GB9019601A
Authority: GB
Inventors: Stefan Renner; Henning Fasterding; Karl-Heinz Koplin
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 1989-09-09
Filing date: 1990-09-07
Publication date: 1991-03-13
Anticipated expiration: 2010-09-07
Also published as: JP2837249B2; DE3930158C2; GB9019601D0; JPH03107356A; GB2235822B; BR9004430A; DE3930158A1

Abstract

A rectifier assembly for motor vehicle alternators has positive and negative diodes (14) respectively inserted by their housings into two metallic, mutually parallel cooling plates (11, 12) between which is disposed a printed circuit board (15) for connecting the diodes (13, 14) to one another as well as to wires of a stator winding of the alternator. On the front, positive cooling plate (11), there is a radially outwardly guided positive terminal (16), which comprises a retaining plate (18) and a bolt (17), which is fastened thereto and projects radially beyond the cooling plates (11, 12). The retaining plate (18) is riveted by spaced rivets (20) onto the front cooling plate (11), and a plastics part (21) is formed onto the outer edge of the circuit board (15) to accommodate the limb (18a) of the retaining plate (18). <IMAGE>

Description

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DESCRIPTION A RECTIFIER ASSEMBLY FOR MOTOR VEHICLE ALTERNATORS

The present invention relates to a rectifier assembly for motor vehicle alternators.

A three-phase alternator is known from EP-A2 0 199 504, in which the terminal, which is marked B+ in accordance with DIN standards, of the rectifier assembly which is disposed in the alternator housing, is radially guided to the exterior. Firstly a terminal bolt is inserted axially into the positive cooling plate of the rectifier assembly and is screwed together with the alternator housing as well as with an angled connector which is an angled retaining plate and carries a radially outwardly directed threaded bolt. The angled connector is in such a case, with the exception of the threaded bolt, encapsulated by an insulating material which protects the terminal with respect to the alternator housing which is connected to earth potential. Such a radial terminalis used in particular if an axial terminal is rendered difficult or impossible due to lack of space at the front end of the alternator when installed in the motor vehicle.

The disadvantage of this solution is that it involves a large number of individual parts, which must be manufactured separately, and when the rectifier assembly is installed in the alternator, the 2- axial terminal bolt must first of all be inserted in order to be able to mount the angled connector with the radially outwardly directed threaded bolt on it.

The present solution proposes a design of max simplicity and reliability for a rectifier device having a radial B+ terminal.

In accordance with the present invention a rectifier assembly for motor vehicle alternators is provided having two metallic. mutually parallel cooling plates, in which positive and negative diodes respectively are inserted by their housings, having a printed circuit board made of insulating material and disposed between the cooling plates, in which are embedded conductors for connecting the diodes to one another and to connecting wires of a stator winding of the alternator. and having on the front one of the two cooling plates, a positive terminal which has a threaded bolt which projects radially beyond the cooling plates and is fastened by way of an angled retaining plate to the front cooling plate and is at least partially enclosed in a plastics part, which retaining plate is secured by at least one rivet to the front cooling plate and the plastics part is formed onto the outer edge of the printed circuit board in such a way that it receives the end of the W W limb of the retaining plate carrying the threaded bolt and rests on the outer edge of the rear cooling plate.

This has the advantage that an axial terminal bolt is dispensed with in that an angled retaining plate having the radially outwardly directed threaded bolt is secured directly to the positive cooling plate.

A further advantage is that it is possible to use the printed circuit board, disposed between the two cooling plates of the rectifier assembly, as the insulated support of both the retaining plate and the radially threaded bolt, such that any bending forces or vibratory stresses on the B+ terminal can be introduced into the two cooling plates of the rectifier assembly. Deformation of the retaining plate is thus reduced by virtue of its support against the outer edge of the rear cooling plate by means of the plastics part formed onto the printed circuit board.

By way of example only, a specific embodiment of the present invention will now be described, with reference to the accompanying drawings, in which:- Fig.1 is a front view of an embodiment of the rectifier assembly of an alternator constructed in accordance with the present invention; i Fig.2 is a cross-section through a part of the front cooling plate having a radial positive terminal; Fig.3 is a cross-section through the positive terminal of the rectifier assembly when assembled; Fig.4 is a partial rear view of the positive terminal of the rectifier assembly; Fig.5 is a partial view of rectifier assembly illustrating the positive terminal constructed in accordance with a second embodiment; Fig.6 illustrates a cross-sectional view along the line B-B of Fig.5; Fig.7 illustrates a cross-sectional view along the line C-C of Fig.5; and Fig.8 illustrates a cross-sectional view along the line D-D of Fig.5.

For both embodiments, the construction of the rectifier assembly according to the invention, which is designated 10, comprises in a known manner in accorodance with German Utility Model No. 87 11 178 a sandwich- type arrangement of two metallic cooling plates or discs 11.12. which extend in a spaced mutually parallel manner. In the outer, or forward, positive cooling plate 11 (shown in Fig.1), a plurality of positive diodes 13 are inserted, whereas, in the rearward, negative cooling plate 12, negative 1 t i -5diodes 14 are inserted, only one of which is shown in Fig.3. Furthermore, there is secured between the two cooling plates 11 and 12 a printed circuit board 15 made of an insulating material, in which are embedded (not illustrated) conductors for connecting the diodes 13r 14 to one another and to connecting wires (not shown) of the stator winding of the respective alternator. The forward, positive cooling plate 11 is provided with a positive terminal 16. which has a threaded bolt 17 projecting radially beyond the positive cooling plate 11. The threaded bolt 17 is provided with an annular shoulder 19 adapted to provide support for the cable shoe of a connecting cable (not shown) at'its upper end and is welded at its lower end to a rearwardly angled limb 18a of a retaining plate 18.

In the embodiment illustrated in Figs. 1 to 4, a radially outwardly directed limb 18b of the retaining plate 18 is.secured by a pair of spaced rivets 20 to the cooling plate 11. One end of the rearwardly angled limb 18a of the retaining plate 18,-which is carrying the threaded bolt 17, projects beyond the outer edge 12a of the rear cooling plate 12. This limb 18a is held in a plastics part 21, which is formed onto the outer edge of the printed circuit board 15 in such a 0.

way that it supports the limb 18a of the retaining plate 18 against the outer edge 12a of the rear cooling plate 12.

When assembling the rectifier assembly 10,-the retaining plate 18 with the threaded bolt 17 is riveted (as best illustrated in Fig.2) by the rivets 20 to the front cooling plate 11. Then the rearwardly angled limb 18a with its two reinforcement ribs 22 is inserted into a corresponding recess-23 of the plastics part 21 on the printed circuit board 15, wherein one half of a collar 24 of the plastics part 21 encloses the lower region of the threaded bolt 17. The other half of the collar is located on a potshaped protective cap (not shown), which is slipped from the outside onto the rectifier assembly 10 and fastened thereto.

The two cooling plates 11 and 12 with the printed circuit board 15 lying therebetween are fixedly connected to one another in an electrically insulated manner by three hollow rivets 25. Using three screws guided through these hollow rivets 25. the'rectifier assembly 10 can then be screwed onto a bearing plate of the alternator (not shown). Using a plurality of external crimped connectors 26 in the printed circuit board 15, the diodes 13 and 14 are electrically 1 k t connected, following assembly of the rectifier assembly 10 on the alternator. to connecting wires of its stator winding.

In order to provide the necessary space in the region of the positive terminal 16r the limb 18b of the retaining plate 18. riveted to the front cooling plate 11, is provided between the two rivets 20 with an opening 27. through which. as best illustrated in Fig.3, one of the crimped connectors 26 passes to the front for contacting a connecting wire of the stator winding with the conductors in the printed circuit board 15.

The crimped connector 26 passing through the opening 27 of the retaining plate 18 is embedded, as can be seen from Fig.3, in a sleeve 28. which is formed onto the printed circuit board 15 and which engages in a corresponding recess 29,30 of the two cooling plates 11,12 respectively. The wall of the sleeve 28 is provided, in the region of the rear cooling plate 12, with guide ribs 31 on opposite sides, which abut on either side against the recess 29 of the rear cooling plate 12 (see Fig.4). As a result, torque forces effective on the threaded bolt 17 are introduced not only by way of the rivet 20 into the front cooling plate 11. but also by way of the guide ribs 31 into the rear cooling plate 12.

In a second embodiment, it is possible to seal the positive terminal 16 against penetration by moisture in an extremely satisfactory manner.

Fig.5 shows the front view of the terminal region of a rectifier assembly 10 of Fig.1, in which the sam parts have been given the same reference numerals. Differing from Fig.1, the angled limb 18a of the retaining plate 18 together with the annular shoulder 19 of the threaded bolt 17 welded thereon is extrusion-coated by the plastics part 21a formed onto the outer edge of the printed circuit board 15. The embedding of the limb 18a with the threaded bolt 17 in the plastics part 21a is shown particularly clearly in Fig.6. A water-tight terminal can be obtained in such case using a rubber sheath which can be pushed onto the extrusion coating 32 of the annular shoulder 19 of the threaded bolt 17. The electrical contact of the retaining plate 18 to the front cooling plate 11 is established in this case using only one rivet 20 as shown in Fig.7. This rivet 20 is on the right-hand side of the limb 18b adjacent to the crimped connector 26, whereas, on the left-hand side of this limb 18b, a hole 33 is provided for holding a guide bolt. The M 1 1 retaining plate 18 is initially placed into an injection mould, retained by the guide bolt secured therein and extrusion-coated by the plastics part 21a, as illustrated in Fig.8, before the front cooling plate 11 is riveted to the retaining plate 18. In this embodiment. torque forces and vibratory forces on the positive terminal 16 are introduced into the two cooling plates 11 and 12 in the same way as in the first embodiment. thus also producing a simple and reliable design for the positive terminal.

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Claims

1. A rectifier assembly for motor vehicle alternators, having two metallic, mutually parallel cooling plates, in which positive and negative diodes respectively are inserted by their housings, having a printed circuit board made of insulating material and disposed between the cooling plates, in which are embedded conductors for connecting the diodes to one another and to connecting wires of a stator winding of the alternator, and having on the front one of the two cooling plates, a positive terminal which has a threaded bolt which projects radially beyond the cooling plates and is fastened by way of an angled retaining plate to the front cooling plate and is at least partially enclosed in a plastics part, which retaining plate is secured by at least one rivet to the front cooling plate and the plastics part is formed onto the outer edge of the printed circuit board in such a way that it receives the end of the limb of the retaining plate carrying the threaded bolt and rests on the outer edge of the rear cooling plate.

2. A rectifier assembly as claimed in claim 1, wherein the threaded bolt, which has an annular shoulder, is welded onto the rearwardly angled limb of the retaining plate.

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3. A rectifier assembly as claimed in claim 1 or 2, wherein the retaining plate is secured by two spaced-apart rivets to the front cooling plate.

4. A rectifier assembly as claimed in claim 3, wherein the front limb of the retaining plate, which is riveted to the cooling plate, has an opening between the two rivets, through which passes one of a plurality of crimped connectors of the printed circuit board for connecting the diodes to the connecting wires of the stator winding.

5. A rectifier assembly as claimed in claim 4, wherein the crimped connector passing through the opening of the retaining plate is embedded in a sleeve which is formed onto the printed circuit board and engages in a corresponding recess respectively on the periphery of the two cooling plates.

6. A rectifier assembly as claimed in one of the above claims, wherein the angled limb of the retaining plate with the annular shoulder of the threaded bolt is extrusion-coated by the plastics part formed on the outer edge of the printed circuit board..

7. A rectifier assembly as claimed in claim 6, wherein the retaining plate is secured on one side of its front limb to the front cooling plate by a rivet and carries on the other side of this front limb a bolt which is also embedded in the plastics part of the printed circuit board.

8. A rectifier assembly for motor vehicle alternators substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.

Published 1991 at The Patent Office. State House. 66171 High Holborn. London WC 1 R 47P. Further copies may be obtained from Sales Branch. Unit 6. Nine Mile Point Cwmfelinfach. Cross Keys. Newport. NPI 7HZ. Printed by Multiplex techniques ltd. St Mary Cray. Kent.