Description

The present invention refers to a wiper device for a small and curved surface, in particular a spherical surface, of an optical element at least partly arranged within a housing, preferably provided by or attached to a motor vehicle, comprising at least one elongate wiper element with two ends, two drive units to which the ends of the wiper element are attached such that the wiper element can be moved on the surface of the optical element by means of the two drive units, and at least one contacting means for bringing the wiping element into contact with the surface of the optical element. The optical surface can be provided by the front element of a wide angle fish-eye lens as used in rearview devices of motor vehicles.

Keeping small and highly curved surfaces clean in rainy conditions poses a challenge for automotive applications. Different wiper devices have been proposed for this purpose.

EP 2 792 556 Al teaches a wiper device for a disc and / or dome-shaped optical element of a motor vehicle. This wiper device comprises at least one elongate wiper element, which has two ends each of which is attached to a drive unit such that the wiper element can be moved from a first end position into a second end position on the surface the optical element by means of the two drive units, guiding means for guiding said movement, and at least one contacting means holding the wiping element in contact with the surface of the optical element. The known wiping element preferably comprises a rigid wiper body, which comprises at least one wiper portion which is formed complementary to the surface of the optical element, and / or an at least bending- resilient body. The known contacting means comprises spring means applying a traction force to the wiping element. The known drive units comprise a shape memory element and apply a linear translational movement to the wiper element. It is the object of the present invention to further develop the known wiper device to enhance the cleaning quality without rendering the structure complicate.

This object is solve in that the contacting means shapes the wiper element around at least that part of the surface, which is exposed to the environment due to an opening provided by the housing and is to be cleaned.

It is preferred that the contacting means is determined by a gap between the surface of the optical element and the housing.

Advantages embodiments of the invention are characterized in that the contacting means is provided by the, in particular circular, opening of the housing for the, in particular spherical, optical element and/or an adaptor means arranged within the opening of the housing, with the adaptor means preferably being adapted to the shape of the optical element, in particular the curvature of said part of the surface to be cleaned.

It is also proposed by the invention that the drive units each comprise a linear actuator and guiding means for guiding the movement of the respective linear actuator.

With the invention it is proposed that the drive units are arranged within the housing and/or are connected to a control unit to move the ends of the wiper element with variable and/or independent speeds.

The wiper element can be flexible.

It is proposed with the invention that the wiper element can be hold tight around said part of the surface and/or can be arranged out of the field of view of the optical element, in particular beneath the optical element, via the drive units, preferably in dependence of the location and/or speeds of the actuators. Beneath the housing is describing a location within the housing which cannot be seen from the outside. The wiper element can have a length reaching around said part of the surface at the point of its highest protrusion with the two actuators at a parallel position, preferably above and below the center of the spherical surface.

It is preferred that the locations and/or speeds of the actuators are controlled in dependence of the distance of the two ends of the wiper element. As the two ends of the wiper element can be moved at different speeds and/or with a time offset to avoid a regular linear movement of the wiper element e.g. from a first end position into a second end position on the surface of the optical element, the cleaning efficiency is increased. The control can, in addition or alternatively, depend on the flexibility of the wiper element, the shape of said part of the surface to be cleaned and/or the contacting means, in particular the shape of the adaptor means, to ensure that the whole surface part exposed to the environment and thus to dirt, rain and the like is cleaned.

At least one sensor, in particular for sensing weather and/or dirt conditions, can be connected to the control unit for adjusting the locations and/or speeds of actuators.

The invention also provides a rearview device for a motor vehicle with at least one wiper device according to the invention. Such a rearview device can comprise a camera and/or a mirror.

Advantages of the invention will be readily appreciated as the same become better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

FIG. 1 shows a cross-section of a wiper device of the present invention in a rearview device of a motor vehicle; and

FIG. 2 shows a frontal view of the wiper device of Fig. 1.

Both figures show an embodiment of a wiper device according to the invention which is especially suited to be used in cooperation with a front element of a wide angle fish-eye lens as used in rearview devices of motor vehicles. The lens 1 is shown with a part of its spherical surface 2, which provides said front element, projecting above a housing 5 to obtain a rearview. Said part is exposed to the environment and thus dirt, rain and the like such that it has to be cleaned from time to time.

A gap 7 is provided between said surface 2 and said housing 5, as the housing 5 has a circular opening with a diameter being lager than the diameter of the lens 1.

An elongated wiper element 10 in form of a flexible strip with two ends is shown. Each end is fixed to a linear actuator 12, 14, with the actuators 12, 14 being arranged beneath the housing 5 on guiding means 16, 18 in order to act as drive units moving said ends and, thus, the wiper element 10.

Not only the lens 1 extends at least partly through the circular opening of the housing 5, but also the wiper element 10. As the gap 7 is provided between the housing 5 and the lens 1 the wiper element 10 can pass from beneath the housing 5, where it is fixed to the actuators 12, 14, and through said gap 7 in order to be moveably hold on the surface 2. The circular opening of the housing 5 keeps the wiper element 10 on the spherical surface 2 at the outside borders thereof and thus ensures a contact between the wiper element 10 and the spherical surface 2. Without the housing 5 and the gap 7 provided by its opening, the wiper element 10 would be inclined to cut the corners at the outside border. In addition, the housing 5 allows for the wiper element 10 to be recessed completely behind the lens 1 and, thus, out of the field of view of the lens 1 , even for a field of view of 180°.

The wiper element 10 is long enough to reach around the curved surface 2 at the point of its highest protrusion with the actuators 12, 14 at a parallel position directly above and below the center of the spherical surface 2, as can be seen in figure 2.

To keep the wiper element 10 tight around the curved surface 2 at all areas, the linear actuators 12, 14 are driven with variable independent speeds. It is possible to increase the distance between the two ends of the wiper element 10 and, therefore, increases the tension applied to the flexible wiper element 10. To further enhance the contact between the wiper element 10 and the curved surface 2 an adaptor means (not shown) can be arranged within the opening of the housing 5. The adaptor means could be adapted to the shape, in particular curvature, of the surface, even allowing to clean non spherical surfaces.

The invention has been described in an illustrative manner. It is to be understood that the terminology, which has been used, is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the invention may be practiced other than as specifically described.

Reference Signs lens

spherical surface

housing

gap

wiper element

actuator

actuator

guiding means

guiding means