Drive device for driving the rotation of a wiper arm, particularly for a panoramic windscreen

Abstract

The invention proposes a drive device (10) for driving a windscreen wiper, which comprises a bearing body (12), a drive shaft (20) which is mounted to rotate with respect to the bearing body (12), a guide housing (19) for guiding the drive shaft (20) in rotation about its axis (A1) which is pivot-mounted with respect to the bearing body (12) about an axis (A2) which is orthogonal to the axis (A1) of the drive shaft (20), a drive motor (16) for driving the shaft (20), a rack (30) and pinion (28) mechanism which causes the shaft (20) to pivot in order to vary the inclination of the axis (A1) of the shaft (20) with respect to the bearing body (12) according to the angular position of the drive shaft (20), characterized in that the drive motor (16) is supported by the guide housing (19).

Claims

1. A drive device for driving the two-directional rotation of a windscreen wiper, which comprises: a bearing body; a drive shaft which is mounted to rotate about an axis with respect to the bearing body; a guide housing for guiding the drive shaft in rotation about the axis which is pivot-mounted with respect to the bearing body about an axis which is orthogonal to the axis of rotation of the drive shaft; a drive motor for driving the two-directional rotation of the drive shaft about the axis of rotation; a mechanism which causes the drive shaft to pivot to vary the inclination of the axis of rotation of the drive shaft with respect to the bearing body according to the angular position of the drive shaft about the axis of rotation, wherein the drive motor is supported by the guide housing.

2. The drive device according to claim 1, wherein the guide housing houses transmission elements which convert the rotation of an output shaft of the motor into a rotational movement of the drive shaft about the axis of rotation.

3. The drive device according to claim 2, wherein the drive motor is an electric motor.

4. The drive device according to claim 2, wherein the output shaft of the drive motor is orthogonal to the drive shaft.

5. The drive device according to claim 2, wherein the orthogonal axis of pivoting of the guide housing with respect to the bearing body and an axis of rotation of the output shaft of the drive motor are coplanar.

6. The drive device according to claim 1, wherein the mechanism comprises a pinion which is supported by the drive shaft to which it is rotationally connected, and a complementary rack which is supported by the bearing body.

7. The drive device according to claim 6, wherein the rack is fixed with respect to the bearing body.

8. The drive device according to claim 6, wherein the transmission ratio between the pinion and the rack varies according to the angular position of the pinion with respect to the rack.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0031] Further features and advantages of the invention will become apparent during the reading of the detailed description that follows, for an understanding of which reference will be made to the attached drawings in which:

[0032] FIG. 1 is a side view of one embodiment of a drive device according to the invention, the various elements and components of which are illustrated schematically;

[0033] FIG. 2 is a view of the device of FIG. 1, from above;

[0034] FIG. 3 is a view of the device of FIG. 1, from the left side;

[0035] FIG. 4 is a view similar to that of FIG. 3, in which the guide housing has pivoted angularly through an angle with respect to the bearing body;

[0036] FIG. 5 is a view similar to that of FIG. 2, in which the guide housing has pivoted angularly by the angle with respect to the bearing body;

[0037] FIG. 6 schematically illustrates the orientation of the wiper blade or blade rubber with respect to the exterior surface of a window that is to be wiped in a first zone of this window;

[0038] FIG. 7 is a view similar to that of FIG. 6 illustrating the orientation of the wiper blade or blade rubber with respect to the exterior surface of a window that is to be wiped in a second zone of this window which is inclined with respect to the first zone;

[0039] FIGS. 8A to 8C are three diagrams illustrating three examples of alternative forms of design of the rack-pinion assembly;

[0040] FIGS. 9A to 9C are three diagrams illustrating the variation in the angular velocity of the pivoting of the guide housing according to the angular position of the windscreen wiper drive shaft, each diagram 9A to 9C being associated with the respective alternative form illustrated in diagrams 8A to 8C respectively.

DETAILED DESCRIPTION OF THE FIGURES

[0041] In the remainder of the description, elements exhibiting an identical structure or similar functions will be denoted by the same references.

[0042] In the remainder of the description, longitudinal, vertical and transverse orientations indicated by the L, V, T trihedron in the figures will be adopted nonlimitingly. A horizontal plane is also defined which extends longitudinally and transversely.

[0043] FIGS. 1 to 3 depict a drive device 10 for driving the reciprocating two-directional rotation, about an axis of rotation A1, of a wiper arm, not depicted.

[0044] The drive device 10 comprises a bearing 12, or bearing body 12, which is intended to be arranged and fixed for example near a window that is to be wiped, on the internal side of a bodywork panel (not depicted).

[0045] For driving the rotation of the wiper arm, the drive device 10 comprises a geared motor assembly 14 which is made up of an electric motor 16 and of a reduction gearbox 18.

[0046] The electric motor 16 comprises an output shaft, or armature shaft, not depicted in detail, which is able to rotate in both directions about the axis A3.

[0047] In the known way, the reduction gearbox 18 makes it is possible on the one hand to step down the rotational speed of the output shaft of the electric motor 16 and, on the other hand, to drive the rotation of a drive shaft 20, or output shaft, which is mounted to rotate in both directions with respect to the housing 19 of the reduction gearbox 18.

[0048] In addition, in the embodiment illustrated in the figures, the reduction gearbox 18 acts as an angle gear so that the axis of rotation A1 is orthogonal to the axis of rotation A3 of the output shaft of the electric motor 16.

[0049] The housing 19 of the geared motor unit 18 is thus a guide housing that guides the rotation of the drive shaft 20 which houses various transmission components and elements that convert the reciprocating two-directional rotation of the output shaft of the electric motor 16 about its axis of rotation A3 into a reciprocating two-directional rotational movement of the drive shaft 20 about its axis A1.

[0050] According to the teachings of the invention, the guide housing 19 that guides the rotation of the drive shaft 20 about its axis A1 is pivot mounted with respect to the bearing body 12 about an axis A2 which is orthogonal to the axis A1 of the drive shaft 20.

[0051] For that purpose, as illustrated schematically in the figures, the housing 19 of the reduction gearbox 18 which supports the electric motor 16 comprises two cylindrical pivot pins 22 which are transversely opposed and aligned along the axis A2.

[0052] Each pivot pin 22 is mounted to rotate in a guide hole 24 formed in the bearing body 12. Thus, the housing 19 of the reduction gearbox 18 which supports the electric motor 16and therefore the geared motor unit 14 as a wholeis mounted to pivot freely, about the axis A2, with respect to the bearing body 12.

[0053] By way of nonlimiting example, the axis A2 of pivoting of the housing 19 with respect to the bearing body 12 and the axis A3 of rotation of the output shaft of the electric motor 16 are coplanar.

[0054] In order to cause the geared motor unit 14 as a whole and, therefore, the drive shaft 20, to pivot with respect to the bearing body 12according to the angular position of the drive shaft 10 about its axis of rotation A1the drive device 10 comprises a mechanism 26 of the rack 30 and pinion 28 type.

[0055] The pinion 28 is supported here by the drive shaft 20 to which it is rotationally connected in both directions as indicated by the arrow in FIG. 2.

[0056] The pinion 28 here is a pinion with straight-cut teeth which extends in a plane perpendicular to the axis A1.

[0057] The rack 30 here is a fixed rack which is fixed to a part 13 of the bearing body 12 as indicated schematically in FIG. 1.

[0058] The rack 30 is designed to complement the tooth set of the pinion 28 and is positioned in space with respect to the latter in such a way that the pinion 28 is always in mesh with the rack 30.

[0059] For that purpose and as can be seen particularly in FIG. 3, the rack 30 has a profile in the shape of an arc of a cylinder about the axis A2 of pivoting of the housing 19 of the reduction gearbox 18 of the geared motor unit 14 with respect to the bearing body 12 to which the rack 30 is fixed.

[0060] Because the rack 30 is fixed, through mechanical reaction, as soon as the drive shaft 20 is rotationally driven in one direction or the other, about its axis A1, by the electric motor 16, the engagement between the tooth set of the pinion 28 and the complementary tooth set of the fixed rack 30 causes the housing 19 to be driven in pivoting about the axis A2.

[0061] The rack and pinion mechanism thus allows control over the inclination of the axis A1 of the drive shaft 20 with respect to the bearing body 12.

[0062] This is illustrated in FIG. 4 where it may be seen that the axis A1 of the drive shaft 20 has been inclined by an angle about the axis A2with respect to its initial position illustrated in FIG. 3.

[0063] This same variation in inclination by an angle can also be seen by comparing FIG. 5 with FIG. 2.

[0064] The reversal of the direction of rotation of the electric motor 16 and therefore of the drive shaft 20 causes the pinion 28 a relative rotation with respect to the rack 30 in the other direction, and therefore causes the housing 19 of the reduction gearbox 18 of the geared motor unit 14 to pivot in the other direction with respect to the bearing body 12.

[0065] FIGS. 6 and 7 schematically depict the effect obtained on the quality of wiping by the pivoting and inclination movements of the drive shaft 20.

[0066] A wiper 100 supported by the wiper arm driven back and forth by the drive shaft 20 and bearing a wiper blade 102 for wiping the exterior surface 104 of a wiped window such as a curved windscreen has been depicted schematically.

[0067] When the inclination of the drive shaft 20 corresponds for example to the position of the components and elements in FIGS. 1 to 3, the wiper 100 is in a central zone of the windscreen and the wiper 100 with the wiper blade 102 extends overall in a direction D1 which is locally orthogonal to the plane of the exterior surface 104 of the windscreen.

[0068] As the wiper 100 sweeps across the surface of the curved windscreen through the rotational driving of the wiper arm it may, as illustrated in FIG. 7, reach another zone of the windscreen in which, locally, the exterior surface 104 forms an angle with respect to the zone 104 previously swept and wiped.

[0069] Thanks to the pivoting and to the inclination obtained of the axis A1 of the drive shaft 20, the wiper 100 with the wiper blade 102 extends overall in a direction D2 which is locally orthogonal to the plane of the exterior surface 104 of the windscreen.

[0070] In terms of alternative forms of design for the rack 30 and pinion 28 assemblies illustrated in FIGS. 8A, 8B and 8C, FIGS. 9A, 9B and 9C schematically depict the variation in the angular velocity of pivoting V as a function of the angle of rotation of the pinion 28.

[0071] In the first example of FIGS. 8A and 9A, the pinion 28 is elliptical in shape with its axis of rotation more or less corresponding to one focus.

[0072] In the second example in FIGS. 8B and 9B, the pinion 28 is a circular pinion with straight-cut teeth, but its drive axis is eccentric.

[0073] In the third example in FIGS. 8C and 9C, the tooth set of the pinion 28 extends along a logarithmic curve.

[0074] In each instance, the pinion 28 is associated with a rack of complementary profile, notably so as to ensure permanent mesh and drive of the two components.

[0075] By way of alternative form which has not been depicted, the guide housing that guides the rotation of the drive shaft 20 could be designed without angle gearing, namely with the drive shaft 20 parallel to the axis A3, for example in the form of an end cap of the electric-motor housing.