Axial locking device for a guide bearing of a rotation axis and associated geared motor

Abstract

Axial locking device for a guide bearing of a rotation axis and an associated geared motor The present invention relates to an axial locking device (13) for a guide bearing (11) of a transmission shaft (4) associated with an electric motor (3) comprising: a frame (15) in which a housing (17) is arranged in an axial direction, the housing being configured to receive the guide bearing (11), the frame comprising a first axial stop (19) configured to axially lock the guide bearing (11) in a first direction, at least one opening (23a, 23b) arranged in the frame (15) in a direction transverse to the axial direction, said at least one opening (23a, 23b) opening at least partially into the housing (17), at least one second axial stop (25a, 25b) configured to be inserted into the at least one opening (23a, 23b), said at least one second axial stop (25a,25b) being configured to axially lock the guide bearing in a second direction, opposite to the first direction. Figure 5,

Description

Title of the invention: Device for axially locking a guide bearing of a rotation axis and associated geared motor

[0001] The present invention is part of the field of bearings for guiding rotation axes, in particular devices for locking these bearings, in particular in geared motors combining an electric motor and a reducer such as the geared motors used in wiping devices of motor vehicles to drive the wiper blades.

[0002] The geared motors comprise, for example, a reducer produced by a worm screw arranged on a transmission shaft driven by the electric motor and a toothed wheel meshing with the worm screw.

[0003] Such geared motors comprise transmission shaft guide bearings for radially guiding the transmission shaft. Such guide bearings are, for example, made of ball bearings.

[0004] However, the gearing of the toothed wheel on the worm screw also causes high axial stresses on the transmission shaft and therefore on the bearings, for example axial forces greater than 1000N, so that the ball bearings must be held axially in position to allow the reducer to withstand such forces.

[0005] Furthermore, the holding part must have a certain axial flexibility to ensure axial holding of the bearing with minimum play. In addition, the walls of the frame and in particular the walls forming the holding grooves must be able to absorb the forces transmitted by the holding part while having a reduced size due to the reduced space available in the geared motor.

[0006] It is therefore appropriate to resolve these problems at least partially and provide a space-saving and inexpensive solution making it possible to obtain axial support for the outer ring of the bearing capable of withstanding the forces imposed by the reducer.

[0007] To this end, the present invention relates to a device for axially locking a guide bearing of a transmission shaft associated with an electric motor comprising: - a frame in which a housing is provided in an axial direction, the housing being configured to receive the guide bearing, the frame comprising a first axial stop configured to axially block the guide bearing in a first direction, - at least one opening provided in the frame in a direction transverse to the axial direction, said at least one opening opening at least partially into the housing, - at least one second axial stop configured to be inserted into the at least one opening, said at least one second axial stop being configured to axially block the guide bearing in a second direction, opposite to the first direction.

[0008] Thus, an outer ring of the guide bearing, for example a ball bearing, comes into abutment against the second axial stop, opposite the first axial stop.

[0009] Such a locking device allows effective axial holding of the guide bearing making it possible to absorb the forces imposed on the guide bearing by the reducer. In addition, such a locking device is produced using elements that are simple to manufacture and whose assembly is also easy, allowing large-scale production and a reduced cost price.

[0010] In some embodiments, the second axial stop comprises an elastic deformation zone configured to deform in the axial direction of the housing.

[0011] Thus, the second axial stop can deform in the axial direction of the housing when it is inserted into the at least one opening.

[0012] In some embodiments, the axial locking device comprises a first opening and a second opening, and wherein the second axial stop comprises a first cross member and a second cross member, the first and second cross members being configured to be inserted into the first and second openings, respectively.

[0013] In some embodiments, the second axial stop comprises at least one pin.

[0014] According to another aspect, the first and second crosspieces are made by pins, in particular axially split pins of the mechanical type.

[0015] The use of industrial pins makes it possible to further reduce the production costs of the locking device.

[0016] According to another aspect of the present invention, the first and second crosspieces are connected by a connecting bridge.

[0017] The use of a connecting bridge makes it even easier to assemble the locking device.

[0018] According to another aspect of the present invention, the second axial stop comprises a convex portion configured to bear on the outer ring of the guide bearing and a recess configured to allow flexion of the convex portion.

[0019] According to another aspect of the present invention, the first and second crosspieces comprise a convex portion configured to bear on the outer ring. of the guide bearing and a recess configured to allow flexion of the convex portion.

[0020] Such a configuration makes it possible to apply a pre-stress to the guide bearing so as to ensure its correct positioning.

[0021] According to one aspect, the at least one opening extends over a length greater than or equal to the diameter of the housing.

[0022] According to another aspect of the present invention, the first and second openings extend over a length greater than or equal to the diameter of the housing.

[0023] According to another aspect of the present invention, the first and second openings extend substantially parallel to each other.

[0024] By substantially parallel is meant that the first and second openings may have an inclination relative to each other of 15° at most.

[0025] According to one aspect, the frame comprises at least one retaining element configured to hold the second stop element in position in the at least one opening.

[0026] According to another aspect of the present invention, the frame comprises first and second retaining hooks for respectively holding the first and second cross members in position in, respectively, the first and second openings.

[0027] According to one aspect, the frame comprises a base and a cover configured to be fixed to the base and to block an axial movement of the second axial stop in the at least one opening.

[0028] According to another aspect of the present invention, the frame comprises a base and a cover configured to be fixed to the base and to block axial movement of the first and second crosspieces in the first and second openings respectively.

[0029] According to another aspect of the present invention, the inner ring of the guide bearing is rotationally coupled to the axis of rotation, for example via laser welding.

[0030] According to one aspect, the second axial stop is made of an alloy containing iron, for example steel.

[0031] According to another aspect of the present invention, the sleepers are made of steel.

[0032] The present invention also relates to a geared motor comprising: - an electric motor configured to rotate a transmission shaft, - a transmission shaft guide bearing, - a locking device as described previously.

[0033] According to one aspect, the geared motor comprises a frame configured to receive the electric motor and the mechanical reducer and in which a housing provided with the first axial stop is provided, said housing being configured to receive the guide bearing.

[0034] According to one aspect, the geared motor comprises a reducer arranged on the transmission shaft and an additional locking device, the locking device and the additional locking device being arranged on either side of the reducer.

[0035] The reducer may be a mechanical reducer. The reducer may be made by a worm screw provided on the transmission shaft and a toothed wheel configured to mesh with the worm screw.

[0036] According to another aspect of the present invention, the geared motor comprises two bearings for guiding the transmission shaft arranged on either side of the worm screw.

[0037] Other characteristics and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and non-limiting example, and the appended drawings among which:

[0038] [Fig-1] represents a schematic view of a geared motor;

[0039] [Fig.2] represents a schematic perspective view of a locking device according to a first embodiment;

[0040] [Fig.3] represents a schematic perspective view of the locking device of the [Fig.2] in assembled state;

[0041] [Fig.4] represents a schematic perspective and sectional view of the device of blocking of [Fig.2];

[0042] [Fig.5] represents a schematic perspective view of a locking device according to a second embodiment;

[0043] [Fig.6] represents a schematic sectional view of the locking device of the [Fig.5] ;

[0044] [Fig.7] represents a schematic view in section and partial of a bearing of guidance;

[0045] [Fig.8a], [Fig.8b], [Fig.8c] represent another embodiment of the device of blockage.

[0046] In these figures, identical elements bear the same references.

[0047] The following embodiments are examples. Although the description refers to one or more embodiments, this does not necessarily mean that each reference relates to the same embodiment, or that the features apply only to a single embodiment. Single features of different embodiments may also be combined or interchanged to provide other embodiments.

[0048] [Fig.l] represents a diagram of a geared motor 1 comprising an electric motor 3, for example a brushless direct current motor comprising a stator 3a and a rotor 3b and configured to drive in rotation a transmission shaft 4, also called an intermediate shaft or armature shaft. The transmission shaft 4 is rotationally fixed to the rotor 3b of the electric motor 3.

[0049] The geared motor 1 also comprises a reducer 5 produced by a worm screw 7 integral in rotation with the transmission shaft 4. The worm screw 7 is for example arranged directly on the transmission shaft 4, for example via a boring process.

[0050] The reducer 5 also comprises a toothed wheel 9 configured to mesh with the worm screw 7. The assembly comprising the worm screw 7 and the toothed wheel 9 is configured to produce a predetermined reduction ratio. An output shaft of the reducer 5 is for example integral in rotation with the toothed wheel 9.

[0051] The geared motor 1 also comprises guide bearings for the transmission shaft 4, produced for example by guide bearings 11, for example ball bearings. In [Fig. 1], there are two guide bearings and they are arranged on either side of the worm screw 7, but a different number of guide bearings and / or a different positioning of the guide bearings is also possible. The different guide bearings can also have different technologies. For example, one of the guide bearings can be produced by a guide bearing 11, for example a ball bearing, while the other guide bearing can be produced by a sleeve-shaped plain bearing. In the case of the present invention, at least one of the bearings is produced by a ball bearing which must be held axially in position. [Fig.7] represents a sectional view of a guide bearing 11 comprising an inner ring 110a, an outer ring 110b and a plurality of balls 110c disposed between the inner ring 110a and the outer ring 110b.

[0052] The present invention relates in particular to a device 13 for axially locking a guide bearing 11 of an axis of rotation, for example a guide bearing of a transmission shaft 4 of a geared motor 1 as described previously, and more particularly for axially locking the outer ring 110b of the guide bearing 11.

[0053] The inner ring 110a of the guide bearing 11 forming the guide bearing is axially locked relative to the transmission shaft 4, for example via laser welding between the inner ring 110a and the transmission shaft 4.

[0054] The axial locking device 13 comprises a frame 15 (visible in [Fig. 2]), for example a protective casing of the geared motor 1, in which is provided a housing 17 configured to receive the guide bearing 11. [Fig. 2] represents an example of a portion of the frame 15 comprising the housing 17. The housing 17 has for example a cylindrical shape and comprises a first axial stop 19, here a counterbore 19 (better visible in the sectional view of [Fig. 6]) configured to lock axially the guide bearing 11 in a first direction according to the axial direction of the housing 17. The counterbore 19 also allows the passage of the transmission shaft 4 guided by the guide bearing 11 via the orifice 21 (see [Fig.6]).

[0055] The axial locking device 13 also comprises at least one opening, here a first 23a and a second 23b openings arranged in the frame 15 in a direction perpendicular to the axial direction D of the housing 17. The first 23a and second 23b openings open at least partially into the housing 17, that is to say that at least a part of the section of the openings 23a, 23b opens into the housing 17 (there is therefore a direct communication between the openings 23a, 23b and the housing 17). The openings 23a and 23b may extend over a length greater than or equal to the diameter of the housing 17. The openings 23a and 23b may extend in a rectilinear manner and parallel to each other. The section of the openings 23a and 23b can be circular as in [Fig.2] but other section shapes can also be used, notably square or oval shapes.

[0056] The axial locking device 13 also comprises a second axial stop, here comprising a first 25a and a second 25b crosspiece configured to be positioned respectively in the first 23a and the second 23b openings. The crosspieces 25a, 25b have for example a shape complementary to the shape of the openings 23a, 23b. Due to the open nature of the openings 23a and 23b in the housing 17, the crosspieces 25a and 25b are configured to come at least partially opposite the guide bearing 11. The openings 23a and 23b are in particular configured so that in the assembled state of the axial locking device 13 shown in [Fig. 3], the crosspieces come opposite the outer ring 110b of the guide bearing 11 so as to axially lock the guide bearing 11 in the housing 17. As shown in [Fig.3], the openings 23a and 23b are in particular positioned so that when the crosspieces 25a, 25b are inserted into the openings 23a, 23b, the crosspieces 25a, 25 come into contact with the outer ring 110b of the guide bearing 11 when the latter is positioned at the bottom of the housing 17 against the counterbore 19 so as to block the guide bearing 11 in the housing 17 in the first and second directions along the axial direction (i.e. along the axis D). The crosspieces 25a, 25b are in particular configured to deform under the effect of contact with the outer ring 110b of the guide bearing 11 when they are inserted into the openings 23a, 23b so as to apply a prestress to the outer ring 110b of the guide bearing 11.

[0057] The crosspieces 25a and 25b are thus configured to come into contact with an external ring 110b of the guide bearing 11 on the side opposite the counterbore 19 and to deform in the axial direction D of the housing 17 when they are inserted into the respective openings 23a and 23b.

[0058] In the example of Figures 2 and 3, the crosspieces are made by pins of generally cylindrical shape and split, for example of the mechanical type. The slot provides radial flexibility allowing the deformation of the pins in the axial direction D when they are inserted into the openings 23a, 23b under the effect of contact with the external ring 110b of the guide bearing 11.

[0059] The crosspieces 25a and 25b can also be connected by a connecting bridge 27 as in the embodiment of [Fig.5] to facilitate their handling and their introduction into the openings 23a and 23b.

[0060] In the embodiment of the axial locking device 13 of [Fig. 5], the crosspieces 25a and 25b comprise a convex portion 250 configured to bear on the outer ring 110b of the guide bearing 11. The crosspieces 25a, 25b also comprise a material recess 252 formed in the crosspiece 25a, 25b. The recess 252 is arranged in a direction perpendicular to the axial direction of the crosspiece 25a, 25b and perpendicular to the axial direction D of the housing 17. The recess 252 is thus configured to allow bending of the convex part 250 of the crosspiece 25a, 25b in the axial direction D in the assembled state of the axial locking device 13. In addition, in the embodiment of [Fig. 5], the section of the crosspieces 25a, 25b is substantially rectangular but other section shapes can also be used.

[0061] The architecture combining convex portion 250 and recess 252 thus makes it possible to obtain flexibility of the crosspiece 25a, 25b in the axial direction D of the housing 17 making it possible to keep the guide bearing 11 pressed against the counterbore 19 as is better visible in the sectional view of [Fig.6].

[0062] Thus, in the case of the split cylindrical pin of the embodiment of Figures 2, 3 and 4 as in the case of the convex portion 250 and the recess 252 in the embodiment of Figures 5 and 6, the crosspieces 25a and 25b apply a stress on the outer ring 110b of the guide bearing 11 to hold it axially against the counterbore 19.

[0063] Furthermore, the length of the openings 23a, 23b which may be greater than or equal to the diameter of the housing 17 (or external diameter of the guide bearing 11) makes it possible to obtain a large bearing surface for the crosspieces 25a, 25b against the wall of the openings 23a, 23b on the side opposite the guide bearing 11 so as to be able to distribute over a large surface the axial forces (in the axial direction D) imposed on the crosspieces 25a, 25b under the effect of the axial force of the transmission shaft 4 transmitted to the guide bearing 11 and consequently to the crosspieces 25a, 25b axially holding the guide bearing 11.

[0064] The crosspieces 25a, 25b are for example made of steel in order to limit the cost of the crosspieces 25a, 25b while providing interesting mechanical characteristics.

[0065] The frame 15 is for example made of aluminum to limit the weight of the frame 15.

[0066] According to a variant, the crosspieces 25a, 25b can be held in position respectively in the openings 23a, 23b by the friction generated between the crosspieces 25a, 25b on the one hand and the wall of the openings 23a, 23b and the outer ring 110b of the guide bearing 11 on the other hand.

[0067] According to another variant, the frame 15 comprises a base and a cover configured to be fixed on the base. The cover is configured to come opposite or even into contact with the entrance of the openings 23a, 23b so as to block the crosspieces 25a, 25b in the openings 23a, 23b when the cover is fixed on the base. The cover is for example screwed onto the base.

[0068] According to another variant, the frame 15 comprises at least one retaining hook for holding the crosspieces 25a, 25b in position in the openings 23a, 23b.

[0069] Another embodiment is shown in Figures 8a to 8c. This embodiment differs from what is described above in that the first axial stop 19 can also be produced by at least one crosspiece 19a, 19b configured to be inserted into at least one opening 231a, 231b provided in the frame 15, the crosspiece opening into the housing 17, so that the crosspiece blocks the guide bearing axially in a first direction. The crosspiece is configured to come into contact with the outer ring of the bearing.

[0070] Here, the first axial stop comprises two crosspieces 19a, 19b, configured to be each inserted into an opening provided in the frame, 231a, 231b respectively.

[0071] For example, as shown, the crosspiece 19a of the first axial stop and the crosspiece 25a of the second axial stop may be connected by a bridge 250a. For example, the frame comprises a groove 230a in which the bridge 250a may be housed.

[0072] For example, as shown, the crosspiece 19b of the first axial stop and the crosspiece 25b of the second axial stop may be connected by a bridge 250b. For example, the frame comprises a groove 230b in which the bridge 250b may be housed.

[0073] This also allows axial locking of the guide bearing in the first and second directions.

[0074] The present invention also relates to a geared motor 1 as shown in [Fig.l] comprising an electric motor 3 configured to rotate a transmission shaft 4, a mechanical reducer 5 produced by a worm screw 7 arranged on the transmission shaft 4 and a toothed wheel 9 configured to mesh with the worm screw 7, at least one guide bearing 11 of the transmission shaft 4 and a frame 15 configured to receive the various elements mentioned above. and comprising a housing 17 provided with a counterbore 19 for receiving the guide bearing 11 and a locking device 13 as described previously.

[0075] As shown in [Fig.l], the geared motor 1 may comprise two guide bearings 11 of the transmission shaft 4 arranged on either side of the worm screw 7, the axial locking device 13 being arranged on one of the two guide bearings 11.

[0076] Thus, in operation, the electric motor 3 rotates the transmission shaft 4 and therefore the worm screw 7, which causes the toothed wheel to rotate. The output of the geared motor 1 is coupled in rotation to the toothed wheel. The assembly comprising the worm screw 7 and the toothed wheel 9 makes it possible to obtain a predetermined reduction ratio. The geared motor 1 is for example used in a wiping device of a motor vehicle. In this case, the output of the geared motor 1 is connected to a linkage driving the wiping arms in a reciprocating movement. In such a configuration, the torque supplied at the toothed wheel 9 and therefore the axial forces on the worm screw 7 and the transmission shaft 4 are significant and are transmitted to the guide bearings 11 of the bearing.The guide bearings 11 are therefore configured to ensure the axial guidance of the transmission shaft 4 relative to the frame 15 but also to absorb the axial forces produced by the gearing between the toothed wheel 9 and the worm screw 7. The configuration of the axial locking device 13 presented previously thus makes it possible to withstand significant forces while limiting the size of the geared motor 1.

Claims

Claims

1. Axial locking device (13) for a guide bearing (11) of a transmission shaft (4) associated with an electric motor (3) comprising: - a frame (15) in which a housing (17) is arranged in an axial direction, the housing being configured to receive the guide bearing (11), the frame comprising a first axial stop (19) configured to axially lock the guide bearing (11) in a first direction, - at least one opening (23a, 23b) arranged in the frame (15) in a direction transverse to the axial direction, said at least one opening (23a, 23b) opening at least partially into the housing (17), - at least one second axial stop (25a, 25b) configured to be inserted into the at least one opening (23a, 23b), said at least one second axial stop (25a, 25b) being configured to axially lock the guide bearing in a second direction, opposite to the first direction.

2. Device (13) according to claim 1 wherein the second axial stop comprises an elastic deformation zone configured to deform in the axial direction of the housing (17).

3. Device (13) according to one of claims 1 or 2 comprising a first opening (23a) and a second opening (23b), and in which the second axial stop comprises a first crosspiece (25a) and a second crosspiece (25b), the first and second crosspieces being configured to be inserted respectively into the first and second openings (23a, 23b).

4. Device (13) according to claim 1 in which the first (25a) and the second (25b) crosspieces are connected by a connecting bridge (27).

5. Device (13) according to one of the preceding claims, in which the second axial stop comprises a convex portion (250) configured to bear on the outer ring (110b) of the bearing (11) and a recess (252) configured to allow bending of the convex portion (250).

6. Device (13) according to one of the preceding claims in which the at least one opening (23a, 23b) extends over a length greater than or equal to the diameter of the housing (17).

7. Device (13) according to one of claims 3 to 7 in which the first (23a) and the second (23b) openings extend substantially parallel to each other.

8. Device (13) according to one of the preceding claims wherein the frame (15) comprises at least one retaining element configured to hold the second stop element (25a, 25b) in position in the at least one opening (23a, 23b).

9. Device (13) according to one of claims 1 to 6 in which the frame (15) comprises a base and a cover configured to be fixed to the base and to block an axial movement of the second axial stop (25a, 25b) in the at least one opening (23a, 23b).

10. Device (13) according to one of the preceding claims in which the second axial stop (25a, 25b) is made of an alloy containing iron, for example steel.

11. Geared motor (1) comprising: - an electric motor (3) configured to rotate a transmission shaft (4), - a guide bearing (11) for the transmission shaft (4), - a locking device (13) according to one of the preceding claims.

12. Geared motor (1) according to the preceding claim, comprising: - a reducer arranged on the transmission shaft (4), - an additional locking device, the locking device and the additional locking device being arranged on either side of the reducer (5).

Images