DRIVE MECHANISM FOR MOVING A WIPER ARM

Drive mechanism configured for moving a wiper arm, the drive mechanism comprising a support assembly configured to cooperate with a wiper shaft extending according to a primary axis to allow a rotation of the wiper shaft with respect the support assembly according to the primary axis; a rotating assembly configured to be mounted in a rotationally fixed manner with the wiper shaft, the rotating assembly including at least one cylindrical bearing extending according to a secondary axis, the secondary axis being transverse to the primary axis; an inclination adjustment assembly including an inclination shaft configured to be fixed to the wiper arm and to cooperate with the at least one cylindrical bearing so as to be allowed to rotate according to the secondary axis, the inclination adjustment assembly further including a radial pin mounted on the inclination shaft and configured to cooperate with a biasing element of the support assembly.

TECHNICAL FIELD

The invention relates to a drive mechanism configured for moving a wiper arm. It also concerns a wiping system for a windshield of a vehicle including said drive mechanism. The invention concerns all sorts of vehicles that use wipers (cars, trucks, . . . ).

BACKGROUND

A drive mechanism for rotating a wiper arm around a wiper shaft of the vehicle is known in the art. It is also known to longitudinally rotate said wiper arm to maintain an orientation of a rubber blade of the wiper arm with respect to a windshield surface of a vehicle.

Generally, to keep a good wiping quality, an attack angle of a tip of the rubber blade should be close to the normal of the windshield surface, i.e. sensibly perpendicular to the windshield surface at the contact point. This should be the case for all positions of the rubber blade in both wiping directions.

If the attack angles are not respected during operation, the wiper arm and the rubber blade may be susceptible to chatter and become noisy when the rubber blade becomes worn. The wiper arm and the rubber blade have a twisting angle from the heel to the tip that is not balanced. This may contribute to poor wipe quality.

Wiper arms have already been proposed to adapt the attack angle of the rubber blade as for example in EP 1 908 654 A1. The described system is particularly complex and includes devices such as gear and endless screws that are particularly expensive and complex to assemble. Due to its complexity, it appears difficult to have correct durability without failures.

Another example, disclosed in WO 97/20717 A1, concerns a wiping system with an articulated wiper axle. Here, important loads and accelerations during operation increase wear on the cam and on the cam ball insert.

US2009/025173 discloses a wiper having a rotation control mechanism including a primary shaft driven in an alternating axially rotating manner, a drive carrier fixed to the primary shaft, a secondary shaft mounted in an axially rotatable manner in relation to the drive carrier, a fixed cam provided with a specific profiled element, and a control element which is fixed to the secondary shaft and cooperates in a sliding manner with the cam profiled element during the displacement of the drive carrier in relation to the fixed cam, where the sliding of the control element along the cam profiled element control the axial pivoting of the secondary shaft.

There is therefore a need for a reliable and cost effective drive mechanism to adapt the attack angle of the rubber blade. This is especially needed for windshields with an aerodynamic shape and a curved design.

SUMMARY

For this purpose, the present invention relates to a drive mechanism configured for moving a wiper arm, the drive mechanism comprising:a support assembly configured to cooperate with a wiper shaft extending according to a primary axis to allow a rotation of the wiper shaft with respect the support assembly according to the primary axis,a rotating assembly configured to be mounted in a rotationally fixed manner with the wiper shaft, the rotating assembly including at least one cylindrical bearing extending according to a secondary axis, the secondary axis being transverse to the primary axis,an inclination adjustment assembly including an inclination shaft configured to be fixed to the wiper arm and to cooperate with the at least one cylindrical bearing so as to be allowed to rotate according to the secondary axis, the inclination adjustment assembly further including a radial pin mounted on the inclination shaft and configured to cooperate with a biasing element of the support assembly, the biasing element being configured to rotate the inclination shaft depending on a displacement of the rotating assembly according to the primary axis with respect to the support assembly.

This arrangement allows modifying the orientation of a rubber blade included in the wiper arm based on the position of the wiper arm in relation to the windshield surface curved shape. This is particularly advantageous when the windshield curvature is particularly important.

This contributes to a good wiping quality and it reduces potential noises and blade chatter. The drive mechanism can be used on the passenger side and on the driver side of a vehicle with all curved windshield definitions provided that the biasing element is adapted to said curvature.

Moving the radial pin with the biasing element constitutes a simple and reliable mechanism, as the constraints on the radial pin are low. Indeed, the inclination adjustment assembly rotates together with the rotating assembly and the displacements of the inclination shaft with respect to the rotating assembly are limited.

According to an aspect of the invention, the radial pin is extending according to a pin axis extending transversally to the secondary axis. Preferably, the inclination adjustment assembly comprises a cylindrical mounting element configured to be attached around the inclination shaft and that includes a fastening location for the radial pin.

According to an aspect of the invention, the radial pin comprises a spherical segment configured to cooperate with the biasing element.

As the radial pin rotates according to the secondary axis, this provision enables to define an optimal contact between the biasing element and the radial pin in every angular position.

According to an aspect of the invention, said spherical segment is comprised in a cam roller of the radial pin.

This provision reduces wear. The drive mechanism is thus durable.

According to an aspect of the invention, the pin axis corresponds to a revolution axis of the spherical segment. According to an aspect of the invention, the radial pin comprises a central part configured to be attached to the fastening location.

According to an aspect of the invention, the biasing element is a cam plate extending transversally to the primary axis and presenting an aperture configured to receive the radial pin.

According to an aspect of the invention, the aperture corresponds to a through opening in the cam plate. The drive mechanism comprises simple components, which implies that it is cost effective and reliable.

According to an aspect of the invention, the aperture presents a closed contour located partially around the primary axis to allow a displacement of the radial pin between two end positions of the rotating assembly around the primary axis.

According to an aspect of the invention, the aperture presents a cooperating surface designed for cooperating with the radial pin, said cooperating surface extending parallel to the primary axis.

According to an aspect of the invention, the support assembly comprises a cylindrical intermediate part on which the biasing element is attached, the cylindrical intermediate part being configured to be mounted on a guiding support of the wiper shaft in a fixed manner.

According to an aspect of the invention, the cylindrical intermediate part comprises a bearing element for cooperating with the wiper shaft. According to an aspect of the invention, the guiding support is configured to be attached to a vehicle and serves as a bearing portion for the wiper shaft.

According to an aspect of the invention, the cylindrical intermediate part comprises radial retaining walls configured to cooperate with complementary radial retaining walls of the biasing element to prevent a rotation according to the primary axis.

According to an aspect of the invention, the radial retaining walls are located on a lug or a notch of the cylindrical intermediate part extending radially and the complementary radial retaining walls are located in a complementary notch or respectively complementary lug of the biasing element.

According to an aspect of the invention, the cylindrical intermediate part comprises radial blocking walls configured to cooperate with complementary blocking walls of the guiding support to prevent a rotation according to the primary axis.

According to an aspect of the invention, the rotating assembly comprises a protective casing wherein the biasing element and the radial pin are located, the protective casing presenting a cylindrical opening for accommodating the inclination shaft, the at least one cylindrical bearing being located inside said cylindrical opening.

According to an aspect of the invention, the protective casing comprises two parts configured to be secured together.

According to an aspect of the invention, the rotating assembly comprises a gripping part configured to fix in rotation the rotating assembly to the wiper shaft.

According to an aspect of the invention, the gripping part is included in or configured to cooperate with the protective casing.

The present invention also concerns a wiping system comprising a drive mechanism as detailed above and a wiper arm including a holder and a rubber blade attached to said holder, the biasing element being configured to adapt an orientation of the rubber blade with regard to a windshield surface of a vehicle on which the wiping system is mounted.

In other words, the inclination shaft is configured for moving the holder around the secondary axis following the actuation of the biasing element.

According to an aspect of the invention, the biasing element is geometrically designed with respect to a curvature of the windshield surface so that an attack angle of the rubber blade remains under a predefined value with regard to the normal at a contact point across a contact length of the rubber blade with the windshield surface.

According to an aspect of the invention, the attack angle is defined, for each section of the rubber blade as the attack angle between the normal at the contact point of a tip of the rubber blade and a central axis of the corresponding section of the rubber blade defined between the tip and a center of the heel of the rubber blade.

The attack angle should be considered according to both directions, i.e. as positive and negative with respect to the normal. According to an aspect of the invention, said predefined value is inferior to 20°, preferably inferior to 15° and in particular inferior to 10°. In other words, it corresponds to 40°, 30° and 20° angle intervals around the normal.

According to an aspect of the invention, the holder comprises a coupling part configured to be mounted fixed in rotation on the inclination shaft, an arm front designed to attach the rubber blade and a retainer linking the coupling part and the arm front.

According to an aspect of the invention, the coupling part includes a cooperating annular element configured to cooperate with the protective casing according to a rotation around the inclination shaft.

According to an aspect of the invention, the holder comprises an articulation device configured to enable a rotation of the retainer with respect to the coupling part according to an unfolding axis extending transversally to the secondary axis.

According to an aspect of the invention, the articulation device comprises a binding element configured to cooperate with a retaining spring of the holder, the retaining spring being configured to be attached to the arm front and to apply a constraint to rotate the retainer in direction of the windshield surface around the unfolding axis.

According to an aspect of the invention, the binding element comprises a hook configured to attach a corresponding part of the retaining spring. Preferably, the binding element is configured to cooperate with a support pin of the coupling part extending parallel to the unfolding axis.

The present invention also concerns a vehicle comprising a windshield, the wiper shaft, the guiding support of said wiper shaft and a wiping system as disclosed above.

The different aspects defined above that are not incompatible can be combined. Further advantages and advantageous features of the invention are disclosed in the following description and in the dependent claims.

In the following detailed description of the figures defined above, the same elements or the elements that are fulfilling identical functions may retain the same references so as to simplify the understanding of the invention.

As illustrated inFIG.1, a vehicle1comprises two wiping systems3. Each wiping system3comprises a drive mechanism5as illustrated inFIGS.2to8.

The drive mechanism5is configured for moving a wiper arm7of the wiping system3, the drive mechanism5comprising a support assembly9configured to cooperate with a wiper shaft11of the vehicle1extending according to a primary axis13to allow a reciprocating rotation of the wiper shaft11with respect the support assembly9along the primary axis13.

The drive mechanism5comprises a rotating assembly15configured to be mounted in a rotationally fixed manner with the wiper shaft11, the rotating assembly15including at least one cylindrical bearing17extending according to a secondary axis19, the secondary axis19being transverse to the primary axis13.

The drive mechanism5also comprises an inclination adjustment assembly21, as illustrated inFIG.7, including an inclination shaft23configured to be fixed to the wiper arm7and to cooperate with the at least one cylindrical bearing17so as to be allowed to rotate according to the secondary axis19.

The inclination adjustment assembly21further includes a radial pin25mounted on the inclination shaft23and configured to cooperate with a biasing element27of the support assembly9, the biasing element27being configured to rotate the inclination shaft23depending on a displacement of the rotating assembly15according to the primary axis13with respect to the support assembly9.

The radial pin25is extending according to a pin axis29extending transversally to the secondary axis19. The inclination adjustment assembly21comprises a cylindrical mounting element31configured to be attached around the inclination shaft23and that includes a fastening location33for the radial pin25.

The radial pin25comprises a spherical segment35configured to cooperate with the biasing element27. Said spherical segment35is comprised in a cam roller of the radial pin25.

The pin axis29corresponds to a revolution axis of the spherical segment35. The radial pin25comprises a central part37configured to be attached to the fastening location33.

As particularly visible onFIG.6, the biasing element27is a cam plate extending transversally to the primary axis13and presenting an aperture39configured to receive the radial pin25. The aperture39corresponds to a through opening in the cam plate.

The aperture39presents a closed contour located partially around the primary axis13to allow a displacement of the radial pin25between two end positions of the rotating assembly15around the primary axis13.

The aperture39presents a cooperating surface41designed for cooperating with the radial pin25, said cooperating surface41extending parallel to the primary axis13. In other word, the pin25follows the entire cooperating surface41during a movement of the wiper from a start to end and back to start position and the spherical segment35rolls on the edge of the aperture39.

The support assembly9comprises a cylindrical intermediate part43on which the biasing element27is attached, the cylindrical intermediate part43being configured to be mounted on a guiding support45of the wiper shaft11in a fixed manner.

The cylindrical intermediate part43comprises a bearing element47for cooperating with the wiper shaft11. The guiding support45is comprised in the vehicle1and serves as a bearing portion for the wiper shaft11.

The cylindrical intermediate part43comprises radial retaining walls49configured to cooperate with complementary radial retaining walls51of the biasing element27to prevent a rotation according to the primary axis13.

The radial retaining walls49are located on a lug or a notch of the cylindrical intermediate part43extending radially and the complementary radial retaining walls51are located in a complementary notch or respectively complementary lug of the biasing element27.

The cylindrical intermediate part43comprises radial blocking walls53configured to cooperate with complementary blocking walls of the guiding support45to prevent a rotation according to the primary axis13.

The rotating assembly15comprises a protective casing55wherein the biasing element27and the radial pin25are located, the protective casing55presenting a cylindrical opening57for accommodating the inclination shaft23, the at least one cylindrical bearing17being located inside said cylindrical opening57.

The protective casing55comprises two parts configured to be secured together.

The rotating assembly15comprises a gripping part59configured to fix in rotation the rotating assembly15to the wiper shaft11. The gripping part59is included in or configured to cooperate with the protective casing55.

As illustrated inFIGS.2and11, the wiping system3comprises a drive mechanism5as detailed above and the wiper arm7.

The wiper arm7includes a holder61and a rubber blade63attached to said holder61and schematically represented inFIG.9, the biasing element27being configured to adapt an orientation of the rubber blade63with regard to a windshield surface65of a vehicle1on which the wiping system3is mounted.

In other words, the inclination shaft23is configured for moving the holder61around the secondary axis19following the actuation of the biasing element27.

The biasing element27is geometrically designed with respect to a curvature of the windshield surface65so that an attack angle67of the rubber blade63remains under a predefined value with regard to the normal69at a contact point71across a contact length73of the rubber blade63with the windshield surface65.

As illustrated inFIG.9, the attack angle67is defined, for each section of the rubber blade63as the attack angle67between the normal69at the contact point71of a tip75of the rubber blade63and a central axis77of the corresponding section of the rubber blade63defined between the tip75and a center of the heel79of the rubber blade63.

The attack angle67should be considered according to both directions, i.e. as positive and negative with respect to the normal69. Said predefined value is inferior to 20°, preferably inferior to 15° and in particular inferior to 10°. In other words, it corresponds to 40°, 30° and 20° angle intervals around the normal69.

As illustrated inFIGS.5,10and11, the holder61comprises a coupling part81configured to be mounted fixed in rotation on the inclination shaft23, an arm front83designed to attach the rubber blade63and a retainer85linking the coupling part81and the arm front83.

The coupling part81includes a cooperating annular element87configured to cooperate with the protective casing55according to a rotation around the inclination shaft23.

The holder61comprises an articulation device89configured to enable a rotation of the retainer85with respect to the coupling part81according to an unfolding axis91extending transversally to the secondary axis19.

The articulation device89comprises a binding element93configured to cooperate with a retaining spring95of the holder61, the retaining spring95being configured to be attached to the arm front83and to apply a constraint to rotate the retainer85in direction of the windshield surface65around the unfolding axis91.

The binding element93comprises a hook97configured to attach a corresponding part of the retaining spring95. Preferably, the binding element93is configured to cooperate with a support pin99of the coupling part81extending parallel to the unfolding axis91.

These arrangements allow modifying the orientation of a rubber blade63included in the wiper arm7based on the position of the wiper arm7in relation to the windshield surface65curved shape. This is particularly advantageous when the windshield curvature is particularly important.

This contributes to a good wiping quality and it reduces potential noises and blade chatter. The drive mechanism5can be used on the passenger side and on the driver side of a vehicle1with all curved windshield definitions provided that the biasing element27is adapted to said curvature.

Moving the radial pin25with the biasing element27constitutes a simple and reliable mechanism, as the constraints on the radial pin27are low. Indeed, the inclination adjustment assembly21rotates together with the rotating assembly15and the displacements of the inclination shaft23with respect to the rotating assembly15are limited.

As the radial pin25rotates according to the secondary axis19, it defines an optimal contact between the biasing element27and the radial pin25in every angular position. Wear is reduced. The drive mechanism5is thus durable.

The drive mechanism5comprises simple components, which implies that it is cost effective and reliable.