FR2855571A1 - SEALED BEARING WITH ECCENTRATION FOR WINDSCREEN WIPER MECHANISM - Google Patents

Abstract

The invention provides a bearing (12) for guiding in rotation of a shaft belonging to a motor vehicle equipment of the type comprising a bearing body which delimits a bore (14) through which axially extends a section of the shaft, with the interposition of an annular eccentric bearing ring (20) so as to be able to adjust the position of the axis of rotation of the shaft relative to the axis of the bore by rotation of the ring (20 ), characterized in that an axial end (32) of the ring (20) is blind so as to constitute a sealed bearing. Application to the guiding of a reducer shaft of the wiper mechanism of a motor vehicle.

Description

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  "Watertight eccentric bearing for wiper mechanism geared motor" The present invention relates to a bearing for guiding in rotation a shaft belonging to a motor vehicle equipment.

  The invention relates in particular to a bearing for guiding in rotation a shaft belonging to a geared motor assembly of a wiper mechanism of a motor vehicle.

  It may for example be a bearing for one of the shafts o0 of the reduction gear which comprises several shafts carrying pinions and / or toothed wheels which must mesh in optimal conditions, on the one hand to avoid a too rapid wear of the teeth and, on the other hand, to avoid operating noises.

  To this end, it is important to be able to adjust the distance between different axes or shafts, parallel or not.

  To this end, it is known to guide a shaft section in rotation by means of a guide bearing of the type comprising a bearing body which delimits a bore through which the section of the shaft extends axially, with the interposition of an annular eccentric bearing ring so as to be able to adjust the position of the axis of rotation of the shaft relative to the axis of the bore by rotation of the ring.

  A first example of such a bearing which can be adjusted by eccentricity is described and represented in document DE-A-4419769 in which the shaft passes through the bearing ring and which offers no particular means enabling adjustment to be carried out easily. .

  Document US-A-6,177,742 describes and shows another design of an annular bearing ring allowing "fine" adjustment of the angular orientation of the ring in the bore of the bearing body.

  However, the proposed design does not make it possible to protect the interior of the geared motor from the penetration of dirt or moisture, that is to say to produce a sealed guide bearing.

  The invention aims to remedy this drawback by proposing a guide bearing of the type mentioned above, characterized in that an axial end of the ring is blind so as to constitute a sealed bearing.

  According to other characteristics of the invention - the blind axial end of the bearing ring is closed by a partition, the external transverse face of which comprises at least one form intended to receive an additional tool for driving the ring in rotation , so as to facilitate the adjustment of the center distance by having shapes arranged at the end of the bearing ring on a transverse surface in the form of a disc of large area; - The bearing ring is a stepped ring which comprises at least a first section of larger external diameter adjacent to its blind axial end and at least a second consecutive section of smaller diameter, so as to allow the use of the ring in a non-machined bore; - The internal concave cylindrical wall of the bearing ring has at least one groove, of generally axial orientation, one end of which opens at the open axial end of the bearing ring to form a vent which facilitates the positioning of the 'shaft in the ring, allowing to expel air 25 contained in the bottom of the ring - the bearing ring is a self-lubricating ring.

  Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended drawings in which: - Figure 1 is a schematic view with partial cutaway which illustrates a wiper mechanism gear motor assembly fitted with an eccentric bearing according to the invention during assembly in the adjustment position; - Figure 2 is a view similar to that of Figure 1 in which the bearing ring is shown in the adjusted and locked position; - Figure 3 is a perspective view of the bearing ring; - Figure 4 is a perspective view of the bearing ring from another angle of view; - Figure 5 is an axial sectional view of the bearing ring along line 5-5 of Figure 6; and FIG. 6 is an axial view at the end of the bearing ring of FIG. 5.

  There is shown in the figures a closure plate 10 belonging to a geared motor wiper mechanism assembly which is for example a part produced by molding.

  The plate 10 comprises several bodies of shaft guide bearings, not shown, including a central bearing 12 which is illustrated in section by a median axial plane.

  The bearing body defines a circular cylindrical internal bore 14, of longitudinal axis X-X and which is delimited by two transverse faces of annular outer or rear end 16 and inner or front 18.

  In known manner, for the guiding in rotation of an axial end of the corresponding shaft, not shown, a self-lubricating bearing ring 20 is interposed radially between the convex cylindrical periphery of the shaft and the internal bore 14.

  The bearing ring 20 is of generally annular cylindrical shape and it is for example made of impregnated steel.

  It defines an internal cylindrical bore 22 whose internal diameter corresponds to the external diameter of the shaft guided in rotation by the ring.

  In accordance with the teachings of the invention, the bearing ring 20 is open axially at its inner or front annular axial end 24, delimited by a transverse annular face of front end 26, and it is blind or closed at its outer axial end or rear, by a transverse wall 28 which thus delimits a bottom 30 and a rear external transverse face 32 in the form of a disc.

  The rear face 32 comprises a peripheral annular rib 34 formed in relief and which comprises three radial grooves 36 distributed 90 from one another, leaving a sector of 180 of the rib 34, devoid of groove 36.

  The internal bore 22 also includes an axial groove 38 which extends from the rear bottom 30 to the annular front end face 24.

  In order to allow a center-to-center adjustment, the bearing ring is of the eccentric or eccentric type, that is to say that the axis 15 of its external circular cylindrical surface 39 is offset with respect to the longitudinal axis of the internal bore 22.

  According to one aspect of the invention, the external surface 39 of the bearing ring is stepped and it has a rear section 40 of large diameter which is extended by a front section 42 of smaller diameter.

  The bearing ring 20 which has just been described is used in the following manner.

  The ring 20 is introduced axially from rear to front into the bore 14 of the bearing body 12, in the position illustrated 25 in FIG. 1 with its front section 42 of smaller diameter which is guided in rotation in the bore 14.

  In this position, there is radial clearance between the section 42 and the bore 14, or else the radial tightening is sufficiently weak to allow the ring 20 to rotate around its longitudinal axis 30 so as to adjust the desired spacing and to test whether this setting is suitable for the correct operation of the gear unit.

  This adjustment is carried out by means of a tool, not shown complementary to the grooves 36 whose asymmetry, which is angularly oriented relative to the offset or eccentricity of the ring, makes it possible to position the ring angularly, for example by means of a tool automated.

  Once this adjustment has been made, the assembly ends axially inserting the ring 20 entirely into the bore 14, 5 that is to say until its rear section 40 of large diameter is force fitted into the bore 14 in the position illustrated in Figure 2.

  During this introduction, the internal axial groove 38 functions as a vent allowing the air trapped between the bottom 30, 32 and the transverse end face of the shaft to be evacuated so as to avoid the formation of 'a compressed air mattress opposing the axial introduction of the ring 20, and this prevents the shaft from being "ejected" after its insertion.

  Of course, the largest diameter of the rear section 40 15 is such that it is then mounted clamped in the bore 14 so as to immobilize the bearing ring in rotation in its angular position previously adjusted.

  Furthermore, the stepped design of the bearing ring 20 makes it possible to use it advantageously in association with a bore 14 that is not machined.

  Its blind sleeve structure allows, once in place, to produce a closed and sealed guide bearing which also makes it possible to avoid any loss of lubricant contained in the reducer.

  The invention is of course applicable to any type of bearing for guiding automotive equipment requiring eccentric adjustment and in which it is not necessary for the bearing to open out at its two front and rear axial ends.

Claims (7)

  1. Bearing (12) for guiding in rotation a shaft belonging to a motor vehicle equipment of the type comprising a bearing body which delimits a bore (14) through which axially extends a section of the shaft, with interposition of an annular bearing ring (20), characterized in that an axial end (28, 30, 32) of the ring (20) is blind so as to constitute a sealed bearing.   2. Guide bearing according to the preceding claim, 10 characterized in that the blind axial end (28, 30) of the bearing ring (20) is closed by a partition (30) whose outer transverse face (32) comprises at least one form (36) intended to receive an additional tool for driving the ring (20) in rotation.   3. Guide bearing according to any one of the preceding claims, characterized in that the bearing ring (20) is a stepped ring which comprises at least a first section (40) of larger external diameter adjacent to its blind axial end (28) and at least one second consecutive section (42) of smaller diameter.   4. Guide bearing according to any one of the preceding claims, characterized in that the internal concave cylindrical wall (22) of the bearing ring (20) comprises at least one groove (38), of generally axial orientation, one end of which opens at the open axial end (24) of the bearing ring (20) to form a vent.   5. Guide bearing according to any one of the preceding claims, characterized in that the bearing ring (20) is a self-lubricating ring.   6. guide bearing according to any one of the preceding claims, characterized in that the bearing is of the eccentric type so as to be able to adjust the position of the axis of rotation of the shaft relative to the axis of l bore by rotation of the ring (20).   7. Guide bearing according to any one of the preceding claims, characterized in that it belongs to a motor vehicle windscreen wiper mechanism reducer.