FR3056846A1 - BRUSHLESS DIRECT CURRENT ELECTRIC MOTOR FOR A MOTOR VEHICLE WIPING SYSTEM - Google Patents

Abstract

The invention relates to a gear motor (1) for a motor vehicle wiper system comprising: - a brushless direct current electric motor comprising: - a rotor (20) comprising magnetic elements (29), - a stator ( 21) having coils of electromagnetic excitation of the rotor, - a rotation shaft (22) integral with the rotor, - a reduction mechanism (3) connecting the rotation shaft (22) and an output shaft (8) of the geared motor . According to the invention, a bearing (23) guiding the rotation shaft (22) to one of the longitudinal ends of the rotation shaft, said bearing (23) being disposed internally to the rotor assembly ( 20) and stator (21) and being housed in a recess internal to the rotor (20), and in which a hollow support (25) carries said magnetic elements (29) and is arranged in a coaxial manner and integral in rotation with the shaft rotation (22), said hollow support (25) capping said bearing (23) guiding the longitudinal end of the rotating shaft (20) on the electric motor side.

Description

© Publication number: 3,056,846 (to be used only for reproduction orders)

©) National registration number: 16 59040 ® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY

COURBEVOIE

©) Int Cl ⁸ : H 02 K 7/116 (2017.01), H 02 K 11/215, B 60 S 1/08

A1 PATENT APPLICATION

©) Date of filing: 09.26.16. © Applicant (s): VALEO WIPING SYSTEMS (30) Priority: Simplified joint stock company - FR. ©) Inventor (s): HERRADA JOSE-LUIS. ©) Date of public availability of the request: 30.03.18 Bulletin 18/13. (56) List of documents cited in the report preliminary research: Refer to end of present booklet (© References to other national documents ©) Holder (s): VALEO WIPING SYSTEMS related: Joint stock company. ©) Extension request (s): @) Agent (s): VALEO WIPING SYSTEMS INDUSTRIAL PROPERTY SERVICE.

BRUSHLESS DIRECT CURRENT ELECTRIC MOTOR FOR MOTOR VEHICLE WIPING SYSTEM.

FR 3 056 846 - A1

The invention relates to a gear motor (1) for a motor vehicle wiping system comprising:

- a brushless direct current electric motor comprising:

- a rotor (20) comprising magnetic elements (29),

- a stator (21) having electromagnetic excitation coils of the rotor,

- a rotation shaft (22) integral with the rotor,

- a reduction mechanism (3) connecting the rotation shaft (22) and an output shaft (8) of the gearmotor.

According to the invention, a bearing (23) guides the rotation shaft (22) to one of the longitudinal ends of the rotation shaft, said bearing (23) being disposed internal to the rotor assembly ( 20) and stator (21) and being housed in a recess internal to the rotor (20), and in which a hollow support (25) carries said magnetic elements (29) and is arranged coaxially and integral in rotation with the shaft of rotation (22), said hollow support (25) covering said bearing (23) guiding the longitudinal end of the rotation shaft (20) on the side of the electric motor.

i

BRUSHLESS DIRECT CURRENT ELECTRIC MOTOR FOR MOTOR VEHICLE WIPING SYSTEM

The present invention relates to a gear motor for a motor vehicle wiping system, as well as a wiping system comprising such a motor reducer.

The gearmotors are essentially composed of an electric motor coupled to a reduction mechanism responsible for increasing the speed to obtain a high rotational transmission torque.

Different types of electric motors can be used in a gear motor, and in particular brushless direct current electric motors which have many advantages such as a long service life, reduced dimensions and consumption as well as a low noise level.

However, the control of electric motors is more complex compared to brushed electric motors because to allow proper operation, it is necessary to know precisely the angular position of the rotor of the brushless DC electric motor ("Brushless" in English) .

Indeed, such electric motors include electromagnetic excitation coils arranged at the stator and supplied alternately via an inverter to allow the rotor to be driven.

However, in order to be able to switch the switches of the inverter (in general six switches with each revolution of the rotor) and therefore the supply of the electromagnetic coils at optimal times to allow the desired rotor drive to be obtained, it is advisable to know at all times the position of the rotor. To this end, the position of the rotor and its angular speed are very often determined by the exploitation of the signals generated by a device which comprises a multipolar magnet, mounted rotating with the rotor, and Hall effect sensors arranged in fixed positions by compared to the magnet.

Document WO 2016/010023 discloses such a gear motor for a motor vehicle wiping system using a brushless DC motor. The brushless motor has a stator with electromagnetic excitation coils for the rotor, and the rotor is rigidly mounted at the end of a rotation shaft. This rotation shaft extends from a housing part for the rotor / stator assembly and up to a part of the housing receiving the reduction mechanism which is a worm gear.

The gear screw is integral with the rotation shaft of the rotor and meshes with the toothed wheel integral with the output shaft of the gear motor.

Notably and as shown in FIG. 4 (or in FIG. 8) of document WO 2016/010023, only two ball bearings are used to guide the rotation shaft of the rotor in rotation, with, on the one hand, a first ball bearing, identified 39 supporting a central part of the rotation shaft, intermediate between the rotor and the worm, and on the other hand, a second bearing at the longitudinal end of the shaft disposed of the 'other side of the worm gear compared to the first bearing.

In particular, the length part of the rotation shaft extending from the first bearing towards the rotor is guided only by the first bearing, the longitudinal end of the shaft protruding from the other side of the rotor being free from guidance.

Such guidance by means of only two bearings differs from the usual practice which conventionally uses a third bearing to guide the distal end of the shaft in rotation near the rotor. According to the inventor's findings, such a guide of the shaft using only two bearings makes it possible to limit the size of the geared motor in the direction of the shaft. On the other hand, the omission of the third bearing is not ideal in terms of mechanical forces, this defect being able to be at the origin of the appearance of vibrations during the setting in rotation of the rotor.

Furthermore, in the known state of the art, whether the shaft guide is with two bearings or with three bearings as previously mentioned, it is customary to always provide a bearing in an intermediate position over the length of the 'rotation shaft, near the worm and another bearing on the longitudinal end of the shaft on the other side of the worm. Such guidance by positioning the bearing as close as possible to the worm makes it possible to limit the deflection of the rotation shaft at the level of this meshing part, and with the aim of ensuring satisfactory operation of the reduction mechanism, without risk shifting of the gear.

In document WO 2016/010023, the intermediate bearing marked 39 is arranged near the multipole magnet of the device ensuring the determination of the position of the rotor. Limiting the deflection of the shaft also makes it possible to maintain, within accepted tolerances, the radial gap between the multipolar magnet and each Hall effect sensor, so as to ensure the proper functioning of the sensor device.

The present invention aims to overcome the aforementioned drawbacks by proposing a geared motor for a wiping system of a motor vehicle, the guiding of the motor shaft of which makes it possible to obtain good compactness along the longitudinal axis of the shaft. rotation, and without sacrificing the dynamic balancing of the electric motor.

Other objects and advantages of the invention will emerge during the description which follows which is given only for information and which is not intended to limit it.

The invention also relates to a geared motor for a motor vehicle wiping system comprising:

- a brushless direct current electric motor comprising:

- a rotor comprising magnetic elements,

- a stator having electromagnetic excitation coils of the rotor,

- a rotation shaft integral with the rotor,

a reduction mechanism connecting the rotation shaft and an output shaft of the gear motor, and in which a bearing guides the rotation shaft to one of the longitudinal ends of the rotation shaft, said bearing being disposed internal to the rotor and stator assembly and being housed in a recess internal to the rotor, and in which a hollow support carries said magnetic elements and is arranged in a coaxial manner and integral in rotation with the rotation shaft, said hollow support coming over said bearing ensuring the guiding of the longitudinal end of the rotation shaft on the side of the electric motor.

According to optional features of the invention, which can be taken alone or in combination:

- Said hollow support extends axially beyond the longitudinal end of the rotation shaft, on the electric motor side;

- the hollow support comprises a sleeve ensuring the fixing of the hollow support on the rotation shaft in a position on the intermediate shaft between the reduction mechanism and the bearing ensuring the guidance of the longitudinal end of the rotation shaft on the side electric motor;

- the sleeve and the rotation shaft are mutually assembled by hooping or gluing;

- a device for determining the angular position of the rotor comprising a multipolar magnet integral in rotation with the rotor, and one or more Hall effect sensors and in which said multipolar magnet takes the form of a ring integral with said hollow support, arranged around said sleeve for fixing said hollow support;

- Said hollow support comprises a section of substantially cylindrical support length, on the circumference of which are secured the magnetic elements of the rotor;

- Said hollow support comprises a shoulder extending radially outward at the distal end of said section of support length of the magnetic elements, said shoulder forming a lateral stop for said magnetic elements of the rotor;

- said hollow support comprises a connection length section connecting the sleeve and said cylindrical support length section, said connection section having vent openings;

- Said hollow support consists of a single piece;

- Said hollow support is a formed sheet;

- a casing forming a protective casing for the electric motor and said reduction mechanism, said casing casing comprising a projecting part towards the inside, penetrating said recess internal to the rotor, and supporting a seat for said bearing, and in which said hollow support comes cover said projecting part of the casing;

the rotation shaft is guided in rotation only by two bearings arranged at the two longitudinal ends of the rotation shaft, including said bearing capped by said hollow support, and another bearing at the other longitudinal end of the rotation shaft, on the reduction mechanism side;

- the reduction mechanism includes a worm / gear wheel system, the worm screw secured to the rotor rotation shaft, the gear wheel secured to the gearmotor output shaft.

The invention also relates to a motor vehicle wiping system comprising one or more wiper blades, a crankshaft mechanism for driving the wiper (s) in a reciprocating movement, as well as 'A geared motor according to the invention, the output shaft of which drives the crankshaft mechanism.

The invention will be better understood on reading the following description accompanied by the attached drawings, among which:

FIG. 1 is a perspective view of a geared motor according to the invention according to one embodiment,

FIG. 2 is a sectional view along a plane passing through the axis of the rotation shaft of the rotor of the electric motor of the geared motor of FIG. 1,

FIG. 3 is a partial view of the geared motor of FIG. 2 illustrating in detail the rotation shaft, said hollow support integral with the shaft, as well as the magnetic elements carried by said hollow support,

- Figure 4 is a partial view of the gear motor of Figure 2 illustrating in detail the rotation shaft, as well as the magnetic elements carried by said support, as well as the flange for closing the casing, including a projecting part.

Also, the invention relates to a geared motor 1 for a motor vehicle wiping system 20 comprising:

- a brushless direct current electric motor comprising:

a rotor 20 carrying magnetic elements, such as permanent magnets,

a stator 21 having electromagnetic excitation coils of the rotor,

a rotation shaft 22 secured to the rotor,

- a reduction mechanism 3 connecting the rotation shaft 22 and an output shaft 8 of the gearmotor.

A casing 4 can form a protective envelope for the electric motor and said reducing mechanism 3.

Such a gear motor comprises a device for determining the angular position of the rotor 20 relative to the stator 21. A control unit (not shown) is configured to generate control signals to supply the electromagnetic excitation coils of the stator 21 as a function of the angular position of the rotor determined by the device for determining the angular position of the rotor.

According to one embodiment, the device for determining the angular position of the rotor may comprise a multipolar magnet 5 integral in rotation with the rotor, and one or more Hall effect sensors (not shown) in fixed positions, capable of detecting changes magnetic domains of the multipolar magnet during the rotation of the rotor.

According to one embodiment, the reduction mechanism 3 can comprise a worm screw 30 / toothed wheel 31 system, the worm screw being secured to the rotation shaft 22 of the rotor 20, the toothed wheel 31 being secured to the shaft outlet 8 of the gear motor. This output shaft 8 is substantially perpendicular to the rotation shaft 22 of the electric motor. The thread of the worm 20 can be obtained from the material coming from the rotation shaft 22, typically made of metal.

A bearing 23 guides the rotation shaft 22 to one of the longitudinal ends of the rotation shaft, on the electric motor side. Notably, this bearing 23 is disposed internal to the rotor 20 and stator 21 assembly, housed in a recess internal to the rotor 20. This end of the rotation shaft can thus be advantageously guided by the bearing 23, without requiring a shaft length such that its end protrudes beyond the rotor. On the other hand, the mounting of this bearing 23 internal to the rotor, does not require having a bearing surface on the useful length section of the rotation shaft external to the rotor, and which is already used to support the screw without thin and / or to support the pole magnet 5: this length section of the shaft external to the rotor can be reduced to a minimum, and with the aim of increasing the compactness of the gear motor in this direction.

To this end, a hollow support 25 carries said magnetic elements 29 on its circumference and is arranged coaxially and integral in rotation with the rotation shaft 22: advantageously this hollow support 25 covers said bearing 23 which guides the longitudinal end of the rotation shaft 20 on the side of the electric motor.

This hollow support 25 can also extend axially beyond the longitudinal end of the rotation shaft 22, on the electric motor side. This makes it possible in particular to arrange said magnetic elements 29 of the rotor at least partially beyond the longitudinal end of the rotation shaft 22, and as illustrated by way of example in FIG. 3. This hollow support is for example a body of revolution which comprises a hollow, tubular part, of internal diameter making it possible to house therein the bearing 23, or even a projecting part 40 of the casing 4, the function of which is described below.

This hollow support 25 may also comprise a sleeve 26 allowing the fixing of the hollow support 25 on the rotation shaft 22. This sleeve 26 is fixed in a position on the rotation shaft 22 intermediate between the reduction mechanism 3 and the bearing 23. The internal diameter of the sleeve 26 can be adjusted to the external diameter of the rotation shaft in this intermediate position. It can be a tight fit allowing assembly by shrinking between the hollow support 25 and said rotation shaft 22. This sleeve 26 can also be fixed to the shaft 22 by gluing.

Note that the multipole magnet 5 can take the form of a ring mounted around the rotation shaft. The magnetic domains (north / south) extend alternately along the circumference of the ring. This multipolar magnet 5 can be integral with said hollow support 25, arranged around said sleeve 26 for fixing said hollow support 25.

Said hollow support 25 comprises a length section 27 for supporting the magnetic elements 29. This support length section 27 is substantially cylindrical. The magnetic elements 29 of the rotor are secured to the external wall of the cylinder. A shoulder 28, in particular in the form of a crown, can extend radially outwards to the distal end of said section 27 of support length of the magnetic elements. This shoulder 28 forms a lateral abutment for said magnetic elements 29 of the rotor 20. This shoulder 28 facilitates the alignment of the magnetic elements along the same diametrical line.

It is also noted that the hollow support 25 has a connection length section connecting the sleeve 26 and said support length section 27, cylindrical, of larger diameter than the sleeve 26. This connection section may have one of the openings vents, angularly distributed around the axis of rotation, ensuring air circulation through said hollow support, in particular to allow cooling of the bearing 23.

The hollow support 25 can consist essentially of an element in one piece, in particular a sheet formed to constitute consecutively, the sleeve 26, the connecting section, the section 27 of cylindrical support, or even said shoulder 28.

The casing of the casing 4 can comprise said projecting part 40 directed towards the inside of the casing 4. As illustrated in FIG. 2, this projecting part 40 penetrates said internal recess in the rotor 3, and supports a seat 41 for said bearing 23. This projecting part 40 is capped by the hollow support 25, at least by said section 27 of cylindrical support length. The projecting part 40 can comprise a tubular wall 47, extending coaxially with the rotation shaft 22, the seat 41 for the bearing being formed at the distal end of the projecting part 40 by a housing for the bearing 23.

This housing can be defined by the internal cylindrical surface of the tubular wall 47, and a shoulder 48 extending radially inwards from the cylindrical surface 47. The bearing 23 comprises an outer ring, an inner ring, and rolling elements, such as balls, the seat 41 of the casing 4 can be of diameter adjusted to the outer ring of the bearing 23. It is also noted that the wall forming a shoulder 48 can be extended to completely close the hollow of the projecting part, if necessary, by forming a cavity 49 in over-depth of the housing for the bearing 23: this cavity 49 in over-depth of the housing is intended to receive a part of the end of the rotation shaft, slightly protruding from the bearing 23. A elastic ring 6, received in a groove in the rotation shaft 22, can make it possible to block the position of the bearing 23 in the corresponding seat 41 of the casing 4.

According to one embodiment, the casing 4 can comprise, on the one hand, an envelope part 44, in particular cylindrical, receiving at least the rotor 20 and the stator 21 of the electric motor, having a lateral opening to the electric motor, and on the other hand, a closing flange 43 ensuring the closing in a removable manner of said lateral opening. According to one embodiment, said projecting part 40 of the casing 4 can be carried by the closing flange 43. The casing part 44 can be a base, in particular made of metal, having fins 46 intended to facilitate the evacuation of the heat.

When the closing flange 43 is removed, the lateral opening authorizes the removal of the components of the electric motor, such as the rotor 20, the stator 21, the rotation shaft 22, the hollow support 25 in particular. This closing flange 43 may comprise a disk-shaped wall 50 extending laterally to the stator and rotor assembly, and having a peripheral rim which cooperates in leaktight manner with an edge complementary to said lateral opening. Said protruding part 40 extends from this disc-shaped wall towards the inside of the internal recess. This disk-shaped wall and the projecting part 40 of the closing flange 43 may be formed by a single piece, in particular metallic.

Maintaining the closing flange 43 against the part 44 can be obtained by means of fixing members 45 passing through the ears of the closing flange 43, typically screwed into tapped bores of the casing part 44.

According to one embodiment, the guiding in rotation of the rotation shaft 22 is ensured only by two bearings 23, 24 arranged at the two longitudinal ends of the rotation shaft 22, namely, on the one hand, said bearing 23 , on the side of the electric motor, capped by the hollow support 25, or even carried by the seat 41 of the projecting part 40, and on the other hand, another bearing 24 at the other longitudinal end of the rotation shaft 22, reduction mechanism side 3.

Each bearing 23 or 24 comprises an outer ring, an inner ring, and rolling elements, such as balls. For each longitudinal end of the rotation shaft, the inner ring of the corresponding bearing 23 (or 24) can be of internal diameter adjusted to the external diameter of the shaft at the corresponding longitudinal end.

A second seat 42, of diameter adjusted to the outer ring receives the bearing 24 ensuring the guiding of the other longitudinal end of the rotation shaft 22, on the reduction mechanism side

3. Locking of the axial position of one and / or the other of the two bearings 23, 24 on the rotation shaft 22 can be ensured by means of an elastic ring 6, 7 received in a groove in the shaft rotation 22.

The elastic ring 6, called the first elastic ring, is received in a first groove in the rotation shaft 22, can make it possible to block the position of the bearing 23 in the corresponding seat 41 of the casing 4. A second elastic ring 7 received in a groove in the rotation shaft 22 blocks the axial position of the other bearing 24 in the other seat 42 of the casing 4. The two elastic rings 6 and 7 can respectively engage in abutment with the two bearings 23 and 24, on the side inside, in order to prohibit their bringing together on the rotation shaft 22.

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It is noted that the diameter of the rotation shaft 22 at the longitudinal ends supported by the two bearings 23, 24 may be greater than the diameter of the shaft at the endless screw 30. It is thus possible to increase the resistance to bending of the rotation shaft 22, by an average increase in the diameter of the rotation shaft. We always obtain a satisfactory operation of the reduction mechanism, in particular without risk of slipping between the screw 30 and the wheel 31 of the gear of the reduction mechanism, and while the guide of the rotation shaft is devoid of guide bearing on a central portion of the tree.

The invention also relates to a motor vehicle wiping system comprising one or more wiper blades, a crankshaft mechanism for driving the wiper (s) in a reciprocating movement, as well as 'A gear motor according to the invention, the output shaft 8 of which drives the crankshaft mechanism.

In such a system, the continuous rotational movement of the output shaft 8 is transformed by the crankshaft mechanism into a reciprocating movement of the wiper (s).

NOMENCLATURE

1. Gear motor,

20. Rotor,

21. Stator,

22. Rotation shaft,

23, 24. Bearings,

25. Hollow support,

26. Fixing sleeve (hollow support 25),

27. Support length section of the rotor magnetic elements (hollow support 25),

28. Shoulder,

29. Magnetic elements of the rotor (ie permanent magnets)

3. Reduction mechanism,

30. worm,

31. Gear wheel,

4. Carter,

40. Protruding part,

41. 42 Seats (bearings),

43. Closing flange,

44. Envelope part (Base),

45. Fixing member (screws),

46. Fins (base),

47. Tubular wall (projecting part 40),

48. Shoulder,

49. Deep cavity,

50. Disc-shaped wall

5. Multipolar magnet,

6, 7. Elastic rings,

8. Output shaft (Geared motor).

Claims (14)

1. Gear motor (1) for a motor vehicle wiping system comprising: 5 - a brushless direct current electric motor comprising: - a rotor (20) comprising magnetic elements (29), - a stator (21) having electromagnetic excitation coils of the rotor, - a rotation shaft (22) integral with the rotor, - a reduction mechanism (3) connecting the rotation shaft (22) and an output shaft (8) of the reduction motorbike10, and in which a bearing (23) guides the rotation shaft (22) to the 'one of the longitudinal ends of the rotation shaft, said bearing (23) being disposed internal to the rotor (20) and stator (21) assembly and being housed in a recess internal to the rotor (20), and in which a hollow support (25) carries said magnetic elements (29) and is arranged 15 coaxially and integral in rotation with the rotation shaft (22), said hollow support (25) covering said bearing (23) guiding the longitudinal end of the rotation shaft (20) on the side of the electric motor. 2. Gear motor according to claim 1, wherein said hollow support (25) extends axially beyond the longitudinal end of the rotation shaft (22), on the motor side 20 electric. 3. Gear motor according to claim 1 or 2, wherein the hollow support (25) comprises a sleeve (26) ensuring the fixing of the hollow support on the rotation shaft (22) in a position on the intermediate shaft between the reduction mechanism (3) and the bearing (23) guiding the longitudinal end of the rotation shaft (20) on the motor side 25 electric. 4. Geared motor according to claim 3, wherein the sleeve (26) and the rotation shaft (22) are joined together by hooping or gluing. 5. Gear motor according to claim 3 or 4, wherein a device for determining the angular position of the rotor comprises a multipole magnet (5) integral in rotation with the rotor (20), and one or more Hall effect sensors and in which said multipolar magnet (5) takes the form of a ring integral with said hollow support (25), arranged around said sleeve (26) for fixing said hollow support. 6. Gear motor according to one of claims 1 to 5, wherein said hollow support (25) comprises a length section (27) of substantially cylindrical support, on the circumference of which are secured the magnetic elements (29) of the rotor. 7. Gear motor according to claim 6, in which said hollow support (25) comprises a shoulder (28) extending radially outwards at the distal end of said section (27) of support length of the magnetic elements. , said shoulder (28) forming a lateral stop for said magnetic elements (29) of the rotor (20). 8. Gear motor according to one of claims 3 to 6, wherein said hollow support (25) comprising a link length section connecting the sleeve (26) and said length section (27) of cylindrical support, said section connection having vent openings. 9. Gear motor according to one of claims 1 to 8, wherein said hollow support (25) is constituted by a single piece. 10. Gear motor according to claim 9, wherein said hollow support is a formed sheet. 11. Gear motor according to one of claims 1 to 10, in which a casing (4) forming a protective casing for the electric motor and said reducing mechanism (3), said casing casing (4) comprises a projecting part (40) inwards, penetrating said internal recess in the rotor (3), and supporting a seat (41) for said bearing (23), and in which said hollow support (25) covers said projecting part (40) of the casing (4). 12. Geared motor according to one of claims 1 to 11, in which the guiding in rotation of the rotation shaft (22) is ensured only by two bearings (23, 24) arranged at the two longitudinal ends of the shaft of rotation (22), including said bearing (23) capped by said hollow support (25), and another bearing (24) at the other longitudinal end of the rotation shaft, on the reduction mechanism side (3) 13. Gear motor according to one of claims 1 to 12, in which the reduction mechanism (3) comprises a screwless fm (30) / toothed wheel (31) system, the screwless fm being integral with the rotation shaft of the rotor, the toothed wheel being integral with the output shaft shaft (8) of the gear motor (1). 5 14. Motor vehicle wiping system comprising one or more wiper blades, a crankshaft mechanism for driving the wiper (s) in a reciprocating movement, as well as a moto- reducer according to any one of claims 1 to 13, the output shaft (8) of which drives the linkage mechanism. 1/4