WO2001089892A1

WO2001089892A1 - Wiper blade for cleaning glass panes, in particular of motor vehicles

Info

Publication number: WO2001089892A1
Application number: PCT/DE2001/001405
Authority: WO
Inventors: Achim Neubauer; Peter-Josef Bauer; Martin-Peter Bolz; Jochen Moench; Hubert Verelst; Joris Grammens; Liesbet Van Vinckenroye
Original assignee: Robert Bosch Gmbh
Priority date: 2000-05-25
Filing date: 2001-04-10
Publication date: 2001-11-29
Also published as: DE10192047D2; DE10025701A1; AU7383701A

Abstract

The invention relates to a wiper blade (40) which is used to clean glass panes (43), in particular motor vehicle panes. The wiper blade has a strip-type, elongated, elastic support element (42), on which an elongated rubber wiper strip (46), which can be placed against the pane, is held parallel to the longitudinal axis. The wiper blade (40), whose central section can be articulated to a wiper arm (48) that is driven in a pendular manner and held under tension against the pane (43), has, when viewed longitudinally, a concave curved profile. When the wiper blade is placed against the pane, said profile passes into a working position, following the contour of the spherically curved pane and approximating to an extended position. A stress, which tensions the end sections (64 and 66) against the pane, is produced in the support element (42). As the section (66) of the wiper strip lying at a greater distance from the pendulum point has a higher tension than the section (64) of the wiper strip (46) lying closer to said pendulum point, the wiping quality is significantly improved, even in the problematic corner areas of the wiper field.

Description

Wiper blade for cleaning windows, especially of motor vehicles

State of the art

In the case of wiper blades of the type referred to in the preamble of claim 1, the support element is intended to ensure as uniform a distribution as possible of the wiper blade contact pressure emanating from the wiper arm on the windshield over the entire wiper blade area. By means of a corresponding curvature of the unloaded support element - i.e. if the wiper blade is not in contact with the windshield - the ends of the wiper strip which is fully applied to the windshield during operation of the wiper blade are loaded by the then tensioned support element to the windshield, even if the radii of curvature of spherically curved vehicle windows change at each wiper blade position. The curvature of the wiper blade must therefore be somewhat stronger than the strongest curvature measured on the windshield to be wiped. The support element thus replaces the complex support bracket construction with two peder rails arranged in the wiper strip, as is practiced with conventional wiper blades (DE-OS1505257).

The invention is based on a wiper blade according to the preamble of claim 1. In a known wiper blade This type (US-PS5485650) is the course of curvature of the support element and thus the curvature of the wiper blade seen in side view and in its longitudinal direction and is symmetrical with respect to a plane placed through the axis of a connection joint present between the wiper blade and wiper arm. This means that, taking into account the curvature of the window, the course of the contact force between the window and the wiper blade starting from the plane to one end of the wiper blade is the same as the course of the contact force from the plane to the other end of the wiper blade. A problem that arises in the process is to be explained with reference to FIG. 1 shown: In the wiping movement (double arrow 12) between pendulum reversal positions 14 in pendulum wiping systems 10, a wiper blade 18 articulated laterally on a driven wiper arm 16 cleans a ring-segment-like wiper field 20, with the wiper arm 16 together with the wiper blade 18 oscillates about an axis 22. The wiper blade 18 is connected in an articulated manner to the free end of the wiper arm 16 in such a way that the wiper blade can swing about an axis 24 in a plane standing on the window and can adapt to the course of the window surface, which deviates from the oscillating plane of the wiper arm. The wiper field limitation results from the two pendulum reversal positions 14 and the wiping radii 26 and 28, of which the outer, larger radius 28 is brought about by the end 30 of the wiper blade 18 remote from the pendulum axis and the inner, smaller radius 26 by the end 32 near the pendulum axis 32 of the wiper blade 18. A peculiarity in such wiper systems can be seen in the fact that the speed at which the wiper blade 18 sweeps over the window increases from the inner radius 26 to the outer radius 28. Thus, the frictional forces as a function of speed decrease continuously from the small radius 26 to the larger radius 28. This produces a moment which acts on the known wiper blade and which surrounds the wiper blade a vertical axis 34 standing on the disk is loaded or tries to rotate. The alternating load (double arrow 36) that results as a function of the constantly changing pendulum direction (double arrow 12) acts on the bearing point between the wiper arm 16 and the wiper blade 18, which must therefore be designed to be correspondingly stable. Vibrations caused by the moment in the wiper arm and in the wiper blade also worsen the wiping result.

Furthermore, in the known wiper blade, the most uniform possible distribution of the wiper blade contact pressure on the window surface to be wiped is to be achieved by a different thickness and / or width of the support element, the central section of the support element having a larger cross-sectional area and thus being stiffer than the smaller ones in the cross-sectional areas and thus more flexible end sections of the support element. Particularly in the case of spherically curved panes with relatively narrow radii of curvature in the lens edge regions and large radii of curvature in the center of the pane, correct adaptation of the wiper strip on the one hand and, at the same time, a proper distribution of the contact force can be problematic, because the cross-section change of the support element alone does not necessarily solve the problem - the optimal support element design - leads .

Advantages of the invention

In the case of the wiper blade with the characterizing features of claim 1, due to the greater load on the end section remote from the pendulum axis, the frictional forces of the two wiper blade sections are approximated to one another or, depending on the circumstances, balanced so that the disadvantageous torque mentioned on the wiper blade is minimized or completely eliminated can. This will the bearing between the wiper arm and wiper blade is considerably relieved and can therefore be dimensioned weaker. At the same time, the measure according to the invention also eliminates a cause for the excitation of the vibrations which are unfavorable for the wiping result and, moreover, decisively improves the wiping out of the problem areas described on the vehicle window.

This is achieved in a structurally simple manner in that the axis of the connecting joint between the wiper arm and the wiper blade, which extends essentially in the pendulum plane, is arranged offset outside the center of the wiper blade toward the end of the wiper blade remote from the pendulum axis.

In the case of particularly problematic wiping conditions, it has proven to be advantageous if the course of curvature of the support element is asymmetrical with respect to a plane which is placed in the axis of the connecting joint and is oriented transversely to the longitudinal direction of the wiper blade. The narrowest curvature is provided where the greatest prestress is required.

This is achieved in a cost-effective manner by designing the support element in such a way that the course of curvature of the support element and thus of the wiper blade from the axis of the connecting joint to the end of the wiper strip remote from the pendulum axis is narrower than its curvature profile from the axis of the connecting joint to the end near the pendulum axis the wiper strip.

In a development of the invention, preloaded spring means, which engage the part of the wiper blade remote from the pendulum axis, act on the wiper blade, in particular on its support element Load the disc. This solution is particularly cost-effective because, in order to implement the invention in the case of wiper blades for different pane configurations, the prestressing of the spring means only has to be adapted accordingly.

An optically inconspicuous design of the spring means results from the fact that, in the case of a wiper blade, its articulation on the wiper arm by means of an articulated bolt arranged on the wiper arm and oriented transversely to the longitudinal extent of the wiper blade, the spring means are formed by a leg spring that wraps around the articulated bolt, one leg of which is supported on the wiper arm and its other spring leg attacks under tension on the wiper blade or on its support element.

For this purpose, the other spring leg is expediently fixed on the part of the supporting element near the pendulum axis. The prestressing of the spring legs is then oriented such that the part of the wiper blade near the pendulum axis is relieved, while the part of the wiper blade remote from the pendulum axis is subjected to a greater load.

Further advantageous developments and refinements of the invention are specified in the following description of exemplary embodiments shown in the associated drawing.

drawing

FIG. 1 shows a basic illustration of a pendulum wiper system for windows of motor vehicles with a wiper blade articulated laterally on the wiper arm and the wiper field covered by the wiper blade, FIG. 2 shows a side view of a wiper blade designed according to a first embodiment of the invention, and FIG. 3 shows a top view 2 shows a side view of a wiper blade designed according to another embodiment of the invention, FIG. 5 shows a further embodiment of a wiper blade according to the invention in partial side view, a connecting device of the wiper blade being cut along the line VV in FIG. 6 and Figure 6 is a plan view of the arrangement of Figure 5 along the line VI-VI in Figure 5 cut.

Description of the embodiments

A wiper blade 40 of a first embodiment of the invention shown in FIGS. 2 and 3 has a band-like elongated, ederelastic, single or multi-part support element 42. On the upper side of the support element facing away from the window 43 to be wiped, a connecting device 44 is arranged in the middle section thereof, by means of which the wiper blade 40 can be detachably connected to a driven wiper arm 48 guided on the body of a motor vehicle. An elongated, rubber-elastic wiper strip 46 is held parallel to the longitudinal axes on the underside of the support element 42 facing the pane. At the free end 47 of the wiper arm 48, counter-connection means are provided which cooperate with a joint pin 50 belonging to the connection device 44 of the wiper blade 40 in the sense of a joint. The wiper arm 48 and thus also the wiper blade 40 are loaded in the direction of the arrow 52 towards the window 43 to be wiped, the surface to be wiped of which is indicated in FIG. 2 by a dash-dotted line 56. Since the dash-dotted line 56 is intended to represent the strongest curvature of the window surface, it is clearly evident that the curvature of the wiper blade 40, which has its ends resting against the window, is stronger than the maximum window curvature. It has - unencumbered - that is, a concave course with respect to the disk. Under the contact pressure (arrow 52), the wiper blade 40 rests with its wiper lip 54 over its entire length on the window surface 56 and changes into a working position approximating the extended position. In the process, a tension builds up in the band-like spring-elastic support element 42, which ensures that the wiper strip 46 or its wiper lip 54 is properly seated on the motor vehicle window 43 over its entire length.

The special configuration of the wiper blade 40 according to the invention according to FIGS. 2 and 3 will now be discussed in more detail below. The wiper blade 40 articulated on the wiper arm 48 via the hinge pin 50 can swing around the axis 58 of the joint during the wiping operation, when the wiper strip 46 lies against its entire length, and can adapt to the course of the window surface. The wiping or oscillating movement is indicated in FIG. 2 by a double arrow 60. The wiper blade 40 oscillates together with the wiper arm 48 about a pendulum axis 62 during the wiping operation. This results in two halves or parts of the wiper blade 40, based on the articulation axis 58, of which one part near the pendulum axis is provided with the reference number 64 and the other part remote from the pendulum axis is provided with the reference number 66. The special design of this embodiment of the wiper blade 40 provides that the part 64 near the pendulum axis is longer than the part 66 away from the pendulum axis. It is therefore the axis 58 of the connecting joint between the wiper arm 48 and the wiper blade 40, which extends essentially in the pendulum plane, outside the center of the wiper blade and away from the pendulum axis End 74 of the wiper blade offset. It is clear that this means that the point of application for the contact pressure (arrow 52), which is displaced towards the end 74 of the wiper blade remote from the pendulum axis, for one Greater load on the part 66 of the wiper blade remote from the pendulum axis and for relief of the part 64 of the wiper blade near the pendulum axis.

A further measure to achieve the desired effect, which is independent of the measure of shifting the contact point for the contact pressure just described, can be seen in the fact that the curvature of the support element 42 and thus of course the curvature of the wiper blade 40 in relation to one in the axis 58 of the connecting joint 50, which is oriented transversely to the longitudinal direction of the wiper blade, is asymmetrical. It can be seen from FIG. 2 that the curvature 68 of the support element 42 is narrower from the axis 58 of the connecting joint to the end 74 of the support element 42 of the wiper blade remote from the pendulum axis than its curve 70 from the axis 58 of the connecting joint to the end 72 of the wiper strip near the pendulum axis , This special shape of the support element or the wiper strip and thus also the wiper blade means that the part 66 of the wiper strip remote from the pendulum axis is preloaded to a greater extent and is therefore also more strongly loaded to the window 43 than the part 64 of the wiper strip near the pendulum axis when the wiper blade is applied the disc reaches this in a working position approximating the stretched position.

Two measures are thus illustrated on the wiper blade according to FIGS. 2 and 3, both of which, independently of one another, contribute to the greater load on the part 66 remote from the pendulum axis. These two measures - the arrangement of the connecting joint outside the center of the wiper blade and the asymmetrical shape of the curvature of the support element or of the wiper blade in relation to a plane lying in the axis 58 and oriented transversely to the longitudinal direction of the wiper blade - can both be used alternatively lead to the desired goal, as well as exercised together as shown in Figures 2 and 3.

4 shows a wiper blade 140 provided with a spoiler 141, the support element 142 of which has a uniform curvature. In this case, the greater load on the pendulum axles wiper blade egg 166 is achieved solely by the fact that the axis 150 of the connecting joint between the wiper arm and the wiper blade 140, which extends essentially in the pendulum direction, is arranged offset outside the center of the wiper blade to the end 174 remote from the pendulum axis. The part 166 of the wiper blade 140 remote from the pendulum axis is therefore shorter than the part 164 of the wiper blade near the pendulum axis. If the wiper blade 140 is placed with its wiper lip 154 on the surface 156 of the pane 143 to be wiped, the stretching associated therewith results in a greater load on the part 166 remote from the pendulum axis solely through the offset of the connecting joint according to the invention.

The wiper blade 240 or its support element 242, which is articulated laterally via a hinge pin 50 connected to the wiper arm 48 and its support element 242, is provided with a connecting device 244, which takes over the mounting of the hinge pin 50. In the exemplary embodiment, the connecting device 244 has walls 245 which extend parallel to one another and are spaced apart from one another and extend in the longitudinal direction of the wiper blade. Between these two walls, the hinge pin 50 is wrapped by a leg spring 250, one 252 of the two spring legs being fixed to the wiper arm 48. The other leg 254 engages with a shoulder 256 under the support element 242 of the wiper blade 240 in the region of its part 264 close to the pendulum axis. The leg spring 250 biased such that the other leg 254 pulls the part 264 of the wiper blade 240 near the pendulum axis in the direction of arrow 260 towards the wiper arm 48 and thereby loads the part 266 of the wiper blade 240 remote from the pendulum axis towards the disc (arrow 267).

All of the exemplary embodiments described have in common that the part 66 or 166 or 266 of the wiper strip remote from the pendulum axis is subjected to a greater load on the pane than the part 64 or 164 or 264 of the wiper strip near the pendulum axis. It goes without saying that the size of this additional load on the part remote from the pendulum axis must always be smaller than the size of the wiper blade contact pressure (arrow 52). Another advantage of all of these problem solutions to be considered as an example is that the wiping quality is improved without disadvantages with regard to oscillating masses and with regard to the drive torque.

Claims

Expectations

1. wiper blade for cleaning windows, in particular of motor vehicles, with a band-like elongated, spring-elastic support element (42) on which an elongated, rubber-elastic wiper strip (46) that can be placed on the window (43) is held parallel to the longitudinal axis and is held in its central section by a pendulum-driven wiper arm (48), is resilient to the windshield and has a concave curvature in the longitudinal direction with respect to the windshield which, when the wiper blade is applied to the windshield, changes into a working position following the spherically curved windshield and approximates an extended position, with a tension being built up in the supporting element, which loads the two halves (64 and 66) of the wiper blade extending from the joint (58) to the windshield, characterized in that the part (66) of the wiper strip remote from the pendulum axis is loaded more strongly to the windshield than the part (64) of the wiper strip close to the pendulum axis (46).

2. Wiper blade according to claim 1, characterized in that the axis (58) of the connecting joint between the wiper arm which extends essentially in the pendulum plane

(48) and wiper blade (40) outside the center of the wiper blade is arranged offset to the end (74) of the wiper blade (40) remote from the pendulum axis.

Wiper blade according to one of Claims 1 or 2, characterized in that the course of curvature of the support element (42) is asymmetrical with respect to a plane which is located in the axis (58) of the connecting joint and is oriented transversely to the longitudinal extent of the wiper blade (40).

Wiper blade according to one of claims 1 to 3, characterized in that the curvature (68) of the support element (42) from the axis (58) of the connecting joint to the pendulum-axis end (74) of the wiper strip is narrower than its curvature (70) from the Axis (58) of the connecting joint from the end (72) of the wiper strip (46) near the pendulum axis.

Wiper blade according to one of Claims 1 to 4, characterized in that prestressed spring means (250) act on the wiper blade (240), in particular on its support element (242), which load the part (266) of the wiper blade (240) remote from the self-aligning bearing to the disc.

Wiper blade according to Claim 5, characterized in that the wiper blade (240) is articulated to the wiper arm (48) by means of an articulated bolt (50) arranged on the wiper arm and oriented transversely to the longitudinal extent of the wiper blade, in such a way that the spring means is carried by a leg spring (250 which wraps around the articulated bolt ) are formed, one leg (252) of which is supported on the wiper arm (48) and the other spring leg

(254) attacks the wiper blade (240) or its supporting element (242) under pretension. Wiper blade according to Claim 6, characterized in that the other spring leg (254) is fixed to the part (264) of the support element (242) close to the pendulum axis.