This invention relates to a combined worm gear and planetary drive for an automobile windscreen wiper system.

In the wiper systems known to the art, a motor is coupled to a rotary link by a worm gearing mechanism. An object of the present invention is to provide a wiper system with a combined worm gear and planetary drive. The d.c. electric motor is coupled to the worm gear at right angles and the planetary drive is assembled to the worm gear in axial alignment. The advantages of this invention are: large speed reduction ratio, high rotational speed of the motor, compactness of the system as a whole.

The accompanying drawings illustrate, by way of example, and not by way of limitation, one of possible embodiments of the wiper system proposed herein, wherein

Fig.l is a front view, shown in isolation, of a wiper motor of the system.
Fig.2 is a sectional view of the motor taken along a line A-A in Fig.l.
Fig. 3 is a sectional view of the motor taken along a line B-B in Fig. 1.

The present invention relates to a combined worm drive 3 and planetary drive 4 with wiper motor 1 in which d.c. motor 2 rotates a rotary link 19 through a planetary drive 4 which is axially assembled to a worm drive 3 and worm drive 3 is assembled perpendicular to armature input shaft 17 to effect movement of a wiper blades. The rotary link 19 is assembled to arm and blade assembly through a four bar linkage.

Wiper motor 1 includes a d.c. motor 2 which is coupled to the worm gear 3 at right angles and planetary drive 4 which is coupled to the worm wheel output shaft 37 in axial alignment. A rotor in which an armature 7 and a commutator 11 are fixed to a rotary input shaft 17, the brushes 12 are in contact with the commutator peripheral surface 11a and the other end of a rotary input shaft 17 has a worm profile 17a.

The motor 2 includes a cylindrical yoke 8 which is placed between spherical bearing end housing 5 and worm wheel housing 14 and magnets 10 are assembled on yoke 8. The motor comprises a brush plate 13 which is assembled on the worm wheel housing 14. The input shaft 17 is supported by four bearings 6,15,16,41, namely spherical bearing 6 at yoke end, ball bearing 15 at gear wheel housing, bush bearing 16 at gear wheel housing, bush bearing 41 at third end to prevent input shaft 17 from loads acting on the input shaft 17. The d.c. motor 2 includes a through bolt 9 which is used to assemble spherical bearing end housing 5 and worm wheel housing 14.

A worm wheel housing 14 comprises a thread to accommodate third end screw 18, press fitted bush 41 to take the load acting on armature input shaft, assembled worm wheel cover plate 33 on worm wheel housing 14, press fitted annulus 30, press fitted bushes 22, 23 to take the loads acting on planetary gear output shaft 27, mounting lugs 14a to assemble on mounting plate, washer 21, cover seal 20, circlip 38 on worm wheel housing 14 to prevent entry of water and dust.

A worm wheel 31 with output shaft 37 is perpendicular to input shaft 17 and d.c. motor 2. The slip ring 35 is assembled on worm wheel 31. The worm wheel output shaft 37 with machined sun gear 37a profile is moulded to worm wheel 31. The loads acting on worm wheel output shaft 37 is taken by two bushes 25,26 at two ends, the bush 26 at inside of cover plate, the other bush 25 at inside of output shaft.

A planetary drive 4 speed reduction is taken through output pins 29 of output shaft 27 which engages with planetary gear bush 28. Washer 36 is assembled between worm wheel housing 14 and planetary gear output shaft 27 to prevent wear. The rotary link 19 is assembled to planetary drive output shaft 27.

A worm wheel cover plate 33 comprises switch fingers 34 mould assembled on it and seal 32 is assembled between worm wheel cover plate 33 and worm wheel housing 14. Connecting wires 39 from switch finger 34 and brush plate 13 are assembled to the connector 40.

It will be appreciated that various other embodiments of this invention are possible without departing from its scope and ambit.

We claim:

1. A combined worm gear and planetary drive for an automobile windscreen wiper system comprising a d.c. motor, a wiper blade and rotary link assembly, characterized by a worm having an input shaft coupled to the said motor perpendicularly; and an output shaft of worm wheel coupled to the input shaft of a planetary gear in axial alignment, the rotary link of the said assembly being mounted on the output shaft of the said planetary gear for actuating the wiper blades of the said assembly, reciprocatingly.

2. A wind screen wiper system as claimed in claim 1 wherein the worm wheel output shaft has a sun gear.

3. A combined worm gear and planetary drive for an automobile windscreen wiper system as claimed in claim 1 wherein the worm wheel cover plate has switch finger mould assembled on it.

4. A combined worm gear and planetary drive for an automobile windscreen wiper system substantially as herein described and illustrated.