FR3055119A1 - ICE WIPER TRAINING - Google Patents

Abstract

Wiper drive (10) for a windscreen wiper installation of a transport means comprising a motor and a transmission, having an output shaft (34) rotatably mounted about an axis (32) for attach the wiper arm (38) (12). The output shaft (34) is integrally rotatably connected to a pinion segment (30) engaged with a screw driven by the motor.

Description

Holder (s): ROBERT BOSCH GMBH.

Extension request (s)

Agent (s): CABINET HERRBURGER.

104 / WIPER DRIVE.

yV) Wiper drive (10) for a wiper installation of a means of transport comprising a motor and a transmission, having an output shaft (34) rotatably mounted about an axis (32 ) to fix the wiper arm (38) (12). The output shaft (34) is integrally connected in rotation to a pinion segment (30) engaged with a screw driven by the motor.

FR 3 055 119 - A1

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Field of the invention

The present invention relates to a wiper drive for a wiper installation fitted to a means of transport comprising a motor and a transmission having an output shaft rotatably mounted about a longitudinal axis, to receive the arm of the wiper installation, the output shaft being driven in rotation about the longitudinal axis by the motor using the transmission.

State of the art

According to the state of the art, windscreen wiper drives are known which are applied to the automobile, comprising an electric motor and a transmission with an output shaft whose end is conical in shape; and to which is attached a wiper arm carrying a wiper blade. The transmission comprises a screw shaft engaged with a screw wheel integral in rotation with the output shaft. The rotational movement of the screw shaft driven by the electric motor is transformed by the screw wheel into an alternating pivoting movement of the wiper arm, at the same time increasing the torque. For this reason, the surface-envelope of the screw wheel has a toothing which surrounds it completely over 360 ° while only a small angular part of this toothing is used for the pivoting movement of the output shaft.

Presentation and advantages of the invention

The present invention relates to a wiper drive for a wiper installation fitted to a means of transport comprising a motor and a transmission having an output shaft rotatably mounted about a longitudinal axis to receive the arm of the wiper installation, the output shaft being driven in rotation about the longitudinal axis by the motor by means of the transmission, this wiper drive being characterized in that the output shaft is integrally connected in rotation to a pinion segment of the transmission engaged with a screw driven in rotation by the motor.

The invention thus allows a considerable saving in material and in weight with at the same time a significant reduction of the size thanks to the pinion segment. The pinion segment according to the present invention is a screw wheel whose geometric shape corresponds substantially to that of a circular disc segment or a circular disc sector.

Preferably, in axial section, ie pinion segment, forms a circle segment having an extension angle of the order of 90 ° -180 ° and preferably equal to 150 °.

There is thus a pinion segment whose extension angle is limited to the extension necessary for the operation of the wiper drive.

According to one development, the peripheral surface of the pinion segment has a toothing which occupies an angular range of between 90 ° up to 180 ° and the angia is preferably equal to 150 °.

There is thus a sufficiently large pivot angle for the output shaft. The angular range of the teeth is preferably identical to that of the angular segment in the form of a disc sector and which may, if necessary, be even less.

Preferably, the teeth have a central region and at least one end region adjacent to the latter at the periphery. This allows the use of different toothing shapes around the periphery of the pinion segment.

Preferably, the toothing of the central zone is a gioboidal toothing.

There is thus a particularly large bearing surface between the teeth and the pinion segment for the pivoting position which is particularly stressed from the mechanical point of view of the pinion segment in connection with the screw in the case of a fixed wiper arm. on the output shaft and which generally takes an intermediate position between the two end positions or end of travel positions; this bearing surface is that of the socket with the screw. The screw preferably has a conventional cylindrical toothing.

Preferably, the toothing of at least one end region is in the form of non-gioboidal toothing. This simplifies mounting of the wiper drive since the pinion segment can first be engaged by only one end region and with the cylindrical toothing of the screw which generally is already in the transmission housing. Then the pinion segment can be turned manually or with the help of the motor until the globoidal teeth are engaged with the screw.

Preferably, at least one end zone occupies an angular range of teeth between 10 ° and 40 °. This makes it easy to mesh the pinion segment with the cylindrical toothing of the screw.

According to one development, the radius of at least one end region is larger than the radius of the central region. Thus, even the small eccentricity of the toothing of the pinion segment with respect to the axis of the output shaft, makes it possible to minimize the radial backlash between the screw and the pinion segment at the zones d end, that is to say end positions in which the output shaft changes direction of rotation.

According to one development, the output shaft has at least one coupling element increasing the torque transmissible to the output shaft by the pinion segment. This coupling element increases the torque transmission capacity between the pinion segment and the output shaft. The coupling element is, for example, a spindle-shaped spacer or the like, oriented radially outwards, and of cylindrical shape, being, for example, welded to the output shaft.

Preferably, at least one coupling element is formed with at least one projecting part, oriented radially outwards and integrated at least by zone in the pinion segment. This allows more torque to be transmitted through the pinion segment to the output shaft.

According to one development, at least one coupling element is formed with a sheet, in particular a perforated sheet or a corrugated sheet.

The larger surface area of the sheet compared to a protruding part in the form of a spacer increases the transmissible torque to the output shaft. The tops of the corrugations of the corrugated sheet are preferably oriented radially outwards.

Preferably, the pinion segment is preferably produced by injection of a thermoplastic material. This makes it possible to produce the particularly complex toothing, at least per segment, in the form of a globoidal toothing of the pinion segment with greater precision and this for an acceptable cost and compatible with mass production.

Preferably, the thermoplastic material is an aliphatic polyamide, in particular polyamide 46 or an aromatic polyamide. This allows operation with less friction, less wear and therefore less transmission noise at a relatively low cost. Preferably, aliphatic polyamide 46 is used.

Preferably, the thermoplastic material is a high performance plastic material, in particular a polyketone, a polyoxymethylene or a polyphthalamide. This further increases the mechanical strength of the transmission while reducing wear and noise.

Preferably, the thermoplastic material comprises a reinforcement of glass fibers, carbon fibers, aramid fibers, natural fibers, glass bodies, graphite, boron nitride or a combination of at least two components mentioned above. This further increases the mechanical strength of the pinion segment.

Drawings

The present invention will be described below, in more detail using an example of wiper drive shown in the accompanying drawings in which the same elements have the same references.

So :

FIG. 1 is a perspective view of an embodiment of a wiper drive comprising a pinion segment, FIG. 2 is a perspective view of the pinion segment of the wiper drive of Figure 1, Figure 3 is a block diagram of the bearing surface between a screw and the pinion segment with non-globoidal toothing, and Figure 4 is a block diagram of the bearing surface between a screw and the segment of pinion with globoid teeth.

Description of an embodiment

FIG. 1 shows a drive 10 for a wiper installation 12 of a means of transport, in particular of a motor vehicle. The wiper drive 10 comprises a motor housing 14 which, by way of example, has a practically cylindrical shape and is continued axially by a transmission housing 16. The motor housing 14 at least partially houses the motor 20 with its shaft 22. The motor 20 is preferably a DC motor, brushless, that is to say electronically switched; it’s an engine called an EC engine. The transmission box 16 at least partially houses a transmission 20 to adapt the speed of rotation or increase the torque of the motor 20.

The transmission 24 preferably comprises a cylindrical screw 26 integral in rotation with the rotor shaft 22. This screw is engaged with a pinion segment 30. As a variant, the screw 26 can also be integrated into the rotor shaft 22 The pinion segment 30 is integral in rotation with the output shaft 34 which is preferably oriented at least essentially, perpendicular to the rotor shaft 22 and is preferably at least by segment, pivoting around its longitudinal axis 32 in the transmission housing 16. As already described above, in the context of the present description, the pinion segment is a segment of a worm wheel having a geometric shape which roughly corresponds to a disc segment (shape circular) or a disk sector.

With the aid of the motor 20 and the transmission 24 which drives it, the output shaft 34, the partly conical end segment 36 of which preferably receives the wiper arm 38 from the installation of wiper 12 of the vehicle by a rotationally integral connection to be driven in an oscillating movement, that is to say in pivoting.

Figure 2 shows the pinion segment 30 of Figure 1 connected in rotation to the output shaft 34, at least preferably substantially cylindrical; this shaft is preferably rotationally symmetrical with respect to the longitudinal axis 32 and its partially conical end segment 36 preferably has a longitudinal groove 40. The pinion segment 30 forms in axial section, preferably a circular segment (disc segment) 42 with an extension angle 44 of between 90 ° and 180 ° and preferably equal to 150 °; its axial height is given the reference 46. The extension angle 44 is here by way of example, equal to approximately 120 °.

The peripheral surface 48, preferably curved in an arc of a circle, oriented radially outward and forming part of the pinion segment 30 preferably comprises a toothing 50 having a toothed angular range 52 also between 90 ° and 180 ° and preferably equal to 150 °. The toothed angular range 52 can be equal to or if necessary smaller than the extension angle 44 of the pinion segment 30. The toothing 50 has here by way of example, a central zone 54 bordered on each side by a end zone 56, 58. The end zones 56, 58 can extend over a toothed angular range 60, 62 between 10 ° and 40 °. In the present example, the toothed angular zones 60, 62 of the end zones 56, 58 correspond by way of example to approximately 30 °. The whole of the toothed angular range 52 is, for example, the sum of the toothed angular range 64 of the central zone 54 increased by the two toothed angular ranges 60, 62 adjacent to the end zones 56, 58. The toothing 50 of the central zone 54 is preferably a toothing 70 globoidal while the toothing 50 of the end zones 56, 58 is a toothing 72, 74 non-globoidal.

The pinion segment 30 may have a geometry different from a shape of a circular sector (disc sector) and preferably at least the toothing 50 follows the outline of an arc of a circle. The radius of the end zones 56, 58 of the toothing 50, of which only the end zone 56 bears the reference of radius R _r so as not to clutter the drawing, is here slightly greater than the radius R _m of the central zone 54 of the toothing 50. The slight eccentricity with respect to the longitudinal axis 32 of the output shaft 34, of the toothing 50 of the pinion segment 30 thus produced minimizes the radial clearance of the toothing, between the screw not shown (see figure 1) and the pinion segment 30 in the end zones 56, 58 of the toothing 50 and thus in the positions of movement reversal of the output shaft 34 of the wiper drive. that is to say in the zones in which the direction of pivoting or rotation of the output shaft 34 changes. The toothing 50 of the pinion segment 30 is produced at the periphery, preferably continuously, that is to say that the globoidal toothing 70 of the central zone 54 joins practically without discontinuity the non-globoidal toothing 72, 74 of the zones d end 56, 58 of the teeth 50.

The pinion segment 30 is preferably made in one piece from thermoplastic material, preferably by injection. The pinion segment 30 can thus be produced in an economical and reproducible manner while respecting the dimensional constraints and furthermore it can be molded by injection together on the output shaft 34. This guarantees a high torque transmission capacity between the segment pinion 30 and output shaft 34.

The thermopiastic material is preferably an aliphatic polyamide, in particular polyamide 46 or also an aromatic polyamide. Thus, the operation of the transmission of the wiper drive 10 of Figure 1 is particularly silent, vibration-free, low friction, low wear and thus practically maintenance-free throughout its life.

The thermoplastic material is, preferably in zones, provided with a reinforcement or a reinforcement, for example, in glass fibers, in carbon fibers, in aramid fibers, in natural fibers, with glass, graphite, boron nitride or a combination of at least two of the reinforcing components mentioned above. The material selection cited above can also be used for the screw 26 of the transmission 24 of Figure 1. In addition, the pinion segment 30 and the screw 26 can also be made of a thermosetting material. The thermoplastic material may include numerous recesses, cavities, passages, crossings, bores, pores and cavities distributed regularly and / or irregularly; in the ideal case, the weight of the pinion segment 30 is reduced, which remains largely neutral from the point of view of its behavior. In addition, to increase the possibility of mechanical stress on the transmission 24 of FIG. 1, it is possible to use a high performance plastic material for the pinion segment 30, such as, for example, a polyketone, a polyoxymethylene or a polyphthalamide.

To further optimize the torque transmission capacity between the pinion segment 30 and the output shaft 34, the output shaft 34 is provided with at least one lever-shaped coupling element 80 produced here by way of 'example, with a pin-shaped protruding part 82, preferably cylindrical. This projecting part is preferably oriented radially and perpendicular to the longitudinal axis 32. In addition, the projecting part 82 is preferably integrated at least in zones in the thermoplastic material of the pinion segment 30.

The protruding part 82 in the form of a spacer is, for example, made of metal and, most advantageously, this part is welded to the latter or otherwise connected to the output shaft 34. The part projecting 82 can be inserted into a transverse bore of the output shaft 34 to create a tight connection or this projecting part 82 can be fixed by cold shrinkage.

As a variant or in addition, at least one coupling element 80 is produced with a sheet 84 deployed as a fan, integral in rotation with the output shaft 34 and preferably integrated at least partially in the thermoplastic material of the pinion segment 30. The sheet 84 has an axial section preferably corresponding largely to the pinion segment 30; preferably this sheet has a shape corresponding to a disc segment of height not referenced and which is preferably significantly less than the axial height 46 of the pinion segment 30. The sheet 84 is preferably completely integrated in the thermopiastic material of the pinion segment 30. It is preferably a perforated sheet not shown or a corrugated sheet not shown and the vertices of the corrugations are oriented radially outward relative to the longitudinal axis 32. The connection between the sheet 84 and the 'output shaft 34 is done, again, by welding, soldering or other assembly techniques, to be difficult to detach or integral or removed only by destruction.

Figure 3 shows the screw 26, preferably cylindrical of Figure 1 engaged with one of the end zones 56, 58 of the teeth 50 of the pinion segment 30 of Figure 1 and Figure 2. The teeth not globoids 72, 74 of the end zones 56, 58 mesh with the screw 26; this means that the engagement with the screw 26 is made with bearing surfaces 100, small, substantially oval, and which, preferably, extend only over a small part of the surface of the sides 102 of the non-globoidal teeth 72 , 74. As a result, the torque transmission capacity, that is to say the possibility of transmitting the torque by the transmission 24 of FIG. 1, is reduced, in particular in the end zones of the shaft. outlet 34 according to Figure 1 and Figure 2 (see in particular Figure 1).

Figure 4 shows the screw 26, preferably cylindrical of Figure 1 and Figure 3 which, alternatively of Figure 3 is shown in engagement with the central region 54 of the teeth 50 of the pinion segment 30 of Figure 1 and of FIG. 2. The meshing of the globoidal toothing 70 with the screw 26 is preferably made at least by a bearing surface 112 substantially in the form of a sector of circular ring and which occupies practically completely the flanks of tooth in engagement 112 of the globoidal toothing 70, in contrast to FIG. 3. The very large bearing surfaces 110 with the sides 112 of the globoidal toothing 70, significantly increase the torque transmission capacity of the transmission 24 of FIG. 1 and of FIG. 2 when the output shaft 34 of FIG. 1 and of FIG. 2 is in the central position.

As a variant of the cylindrical screw 26 shown here, this screw can also be produced as a globoidal screw. The end zones of the pinion segment 30 provided with a non-globoidal toothing however simplifies the assembly of the pinion segment 30 which, moreover, is provided with a globoidal toothing 70. For the assembly of the drive d 'wiper 10 of Figure 1, we first introduce the screw 26 only in the transmission housing (see Figure 1). Then the pinion segment 30 is rotated, preferably with respect to the longitudinal axis 32 according to FIG. 1 and FIG. 2, so that first of all one of the two end segments 56, 58 of the Figure 3 of the pinion segment 30 engages with the screw 26 through the non-globoidal toothing 72. This avoids having to mesh the screw 26 in the pinion segment 30. Alternatively, it is also possible to place the pinion segment 30 when the screw 26 is already installed in the transmission housing 16 of FIG. 1 so that the screw 26 is on the side opposite the toothing 50 of the pinion segment 30, that is to say on the toothless side of the pinion segment 30.

By slightly activating the motor 20 of FIG. 1 with a low electric voltage which is just sufficient to start the motor 20, the pinion segment 30 is slowly rotated (ie if necessary using in addition a suitable spring to generate the force peripheral) in screw 26 to mesh slowly. After the complete assembly of the screw drive 10 of FIG. 1, it is possible, ie if necessary, to place at least one mechanical stop for the pinion segment 30 in the transmission housing 16 and pivot the pinion segment 30 in return. using the motor 20 until it reaches the stop to guarantee an output position defined for the output shaft 34.

NOMENCLATURE OF MAIN ELEMENTS

Wiper drive

Wiper installation

Motor housing

Transmission box

Engine

Rotor shaft

Transmission

Cylindrical screw

Pinion segment

Longitudinal axis

Wiper drive output shaft

Wiper arms

Longitudinal flute structure

Circle segment

Extension angle

Peripheral surface

Teeth

Central area

End zone

End zone

Toothed angular range

Toothed angular range

Toothed angular range

Globoidal teeth

Non globoidal teeth

Non globoidal teeth

Coupling element

Protruding part

Fan-shaped sheet

Tooth flank

Load-bearing surface

Tooth flank

Claims (15)

1) Wiper drive (10) for a wiper installation (12) fitted to a means of transport comprising a motor (20) and a transmission (24), the transmission (24) having a shaft of output (34) rotatably mounted about a longitudinal axis (32), to receive the arm (38) of the wiper installation (12), the output shaft (34) being rotated about of the longitudinal axis (32) by the motor (20) using the transmission (24), wiper drive characterized in that the output shaft (34) is connected in rotation with a pinion segment (30) of the transmission (24) and this pinion segment (30) is engaged with a screw (26) driven in rotation by the motor (20). 2 °) Wiper drive according to claim 1, characterized in that the pinion segment (30) corresponds to an axial sector of circular segment (42) whose angle (44) is between 90 ° and 180 °, preferably equal to 150 °. 3 °) Wiper drive according to claim 1 or 2, characterized in that the peripheral surface (48) of the pinion segment (30) has a toothing (50) occupying a range (52) between 90 ° and 180 ° and, this angle preferably being equal to 150 °. 4 °) wiper drive according to claim 3, characterized in that the toothing (50) has a median range (54) and at least one end region (56, 58) following the periphery to the range median. 5 °) Wiper drive according to claim 4, characterized in that the toothing (50) of the central region (54) is a globoidal toothing (70). 6 °) Wiper drive according to claim 4 or 5, characterized in that the toothing (50) of at least one end region (56, 58) is in the form of a non-globoidal toothing ( 72, 74). 7 °) Wiper drive according to one of claims 4 to 6, characterized in that at least one end zone (56, 58) occupies an angular range (60, 62) between 10 ° and 40 °. 8 °) Wiper drive according to one of claims 4 to 7, characterized in that the radius (R _r ) of at least one end region (56, 58) is greater than the radius (R _m ) from the central area (54). 9 °) Wiper drive according to one of claims 1 to 8, characterized in that the output shaft (34) has at least one coupling element (80) to increase the torque transmissible to the shaft outlet (34) by the pinion segment (30). 10 °) Wiper drive according to claim 9, characterized in that at least one coupling element (80) is formed of at least one projecting part (82) oriented radially outward and integrated in the less per zone, in the pinion segment (30). 11 °) Wiper drive according to claim 9 or 10, characterized in that at least one coupling element (80) is formed with at least one sheet (84), in particular a perforated sheet or a corrugated sheet. 12 °) Wiper drive according to one of claims 1 to 11, characterized in that the pinion segment (30) is made of injected thermoplastic material. 13 °) Wiper drive according to claim 12, characterized in that the thermoplastic material is an aliphatic polyamide, in particular a polyamide 46 or an aromatic polyamide. 14 °) Wiper drive according to claim 12, characterized in that the thermoplastic is a high performance plastic including a polyketone, polyoxymethylene or polyphthalamide. 15 °) Wiper drive according to one of claims 12 to 14, characterized in that the thermoplastic material comprises a reinforcement of glass fibers, carbon fibers, aramid fibers, natural fibers, glass, graphite, boron nitride or a combination of at least two of the components mentioned above. 1/3 Ο) —4 ~ I Ο CO CO CN 2/3 l · —32