FR2779109A1 - Vehicle window wiping system - Google Patents

Abstract

The windscreen wiper mechanism is driven by means of a drive shaft through a transmission mechanism, which consists of a cable (24), with the primary end (28) fixed, and with the drive section (36) driving through the pulley (20) the wiper drive shaft (A1 ). The operating element (48) is located to act on the two primary sections (40 and 44) of the cable, by rotating eccentrically around the main drive shaft (A3). The second end of the cable is fixed by a spring to maintain the tension in the cable.

Description

The invention relates to a system for wiping a vehicle window.

automobile with a mechanism

cable drive.

  The invention relates more particularly to a system for wiping a window of a motor vehicle, of the type in which at least one wiper is driven in a rotary sweeping movement alternated by a drive shaft itself driven by a rotary motor by

  through a transmission mechanism.

  Generally, the transmission mechanism is a connecting rod and crank system in which two cranks integral in rotation respectively with the motor shaft and the drive shaft are connected to each other by a connecting rod so as to transform the continuous one-way rotary movement of the motor shaft into an alternating rotary movement of

the drive shaft.

  Such a device, which uses rigid, relatively bulky and heavy parts, is penalizing in terms of ease of installation of the wiping system on the

vehicle.

  It is also known, for example from the document DE-A-

  1.050.677, drive mechanisms in which the drive shaft comprises a pulley on which a cable is wound. However, in such a system, it is necessary to control the rotary motor so that it provides directly, or by means of another connecting rod / crank system, a back-and-forth movement.

alternative to cable.

  The invention therefore aims to provide a new motor vehicle wiping system, which uses a cable for driving the wiper shafts, this in order to facilitate the installation of the system on the vehicle, but which also allows the use of a rotary motor controlled by

one-way and continuous.

  To this end, the invention proposes a windscreen wiper of the type described above, characterized in that the transmission mechanism comprises a cable of which a first end is fixed and of which a drive section is wound without sliding around. a pulley which is integral in rotation with the drive shaft, in that the mechanism comprises an actuator which acts on a first section of the 1o cable included between the first end and the drive section, in a direction not parallel to the path of the first section of the cable between the point of attachment of the first end and the pulley, to vary the length of the path of the first section alternately, and in that the mechanism includes means for keeping the

first section.

  According to other characteristics of the invention - the second end of the cable is connected to elastic return means which keep the cable in tension - the second end of the cable is fixed, and the mechanism comprises an actuator which acts on a second section of the cable between the second end and the drive section, in a direction not parallel to the path of the second section of the cable between the fixing point of the second end and the pulley, to vary the length of the path of the second section of inversely to the variation in length of the first section; - the system includes a single actuator which acts on the two sections; - The system comprises two wipers each driven by a drive shaft, the shafts being secured respectively to a first and a second pulley, and it comprises two transmission mechanisms incorporating any of the preceding characteristics which cause each one of two trees; the two transmission mechanisms include a common single actuator; - The system comprises two wipers each driven by a drive shaft, the shafts being secured respectively to a first and a second pulley, and the cable drive section is wound without sliding o around the two pulleys; - The actuator is a roller which is driven in one-way rotation by the motor, and the roller acts on the cable by a peripheral surface which is eccentric with respect to. The axis of rotation of the motor; - The roller is cylindrical with an axis parallel to the axis of rotation of the motor - the first and the second section of the cable cooperate with portions of the peripheral surface of the roller which are diametrically opposite with respect to the axis of the roller; - The attachment points of the ends of the first and second sections are arranged geometrically at the two opposite corners of a trapezoid at the other two corners of which are arranged return rollers against which the first and second sections are supported respectively; - the axis of rotation of the motor is arranged inside the trapezoid; and - the axis of rotation of the motor is arranged substantially at

  the intersection of the two diagonals of the trapezoid.

  Other characteristics and advantages of the invention

  will appear on reading the detailed description which follows

  for the understanding of which reference will be made to the appended drawings in which - Figure 1 is a schematic perspective view illustrating a first embodiment of the invention in which the wiping system comprises two wipers; - Figures 2 to 5 are schematic plan views illustrating the wiping system of Figure 1 in different positions; - Figures 6 to 9 are views similar to those of views 2 to 5 in which is illustrated a second embodiment of the invention; - Figure 10 is a plan view of a third mode

for carrying out the invention.

  There is shown schematically in Figure 1, part of a wiping system of a motor vehicle window. More particularly, two drive shafts 10, 12 are shown which are mounted to rotate about their respective axes A1, A2 relative to the vehicle body (not shown) and on which two wipers are intended to be mounted. (not shown) which are each

  intended for wiping the vehicle window.

  The drive shafts 10, 12 are intended to be driven in rotation, in an alternating rotary sweeping movement, by an electric motor 14 whose motor shaft 16 is

  of axis A3 substantially parallel to axes A1 and A2.

  The motor 14 drives the shafts 10, 12 by means of a conforming transmission mechanism 18

to the teachings of the invention.

  As can be seen in FIG. 1, each shaft 10, 12 carries a pulley 20, 22 with an axis coaxial with the shaft

  corresponding and integral in rotation thereof.

  In this first embodiment of the invention, each shaft 10, 12 is driven by the motor 14 by

  via a cable 24, 26.

  Each cable 24, 26 has two ends 28, 30 and 32, 34 which are fixed in a manner not shown on the body of the vehicle. For each cable 24, 26, the cable comprises a drive section 36, 38 which is wound around the pulley 20, 22 of the corresponding shaft 10, 12. Between the first end 28, 32 and the drive section 36, 38, each cable has a first section 40, 42. Between the second end 30, 34 of each cable and the corresponding drive section 36, 38,

  each cable has a second section 44, 46.

  According to the invention, the drive sections 36, 38 cannot slide on the corresponding pulley 20, 22. In this way, by exerting traction on one or the first or second section of the cable, a rotation is caused

  proportional to the drive shaft 10, 12.

  In accordance with the teachings of the invention, the wiping system comprises an actuator, here produced in the form of a cylindrical roller 48 whose axis A4 is parallel to

  the axis A3 of the engine 14 but is not confused with the latter.

  The roller 48 is integral with the motor shaft 16 so that when the latter is rotated by the motor 14, the roller 48 describes around the axis A3 a circular path at the

way of an eccentric.

  The roller 48 is intended to cooperate simultaneously, by its external cylindrical surface 50, with the first and second sections of the two cables 24, 26 in order to vary the length of the path of the first and second alternately.

  section, in this case in reverse quantities.

  The operation of the invention will now be more particularly explained with reference to FIGS. 2 to 5 in which the operation of the device has been illustrated.

  drive of only one of the two shafts 10, 12.

  By convention, the drive section 36 may be called the portion of the cable 24 which, at a given instant, is actually in contact with the pulley 20. In this way, the first section 40 is the portion of the cable 24 which extends between the first end 28 and the pulley 20. Similarly, the second section 44 is the portion of the cable 24 which extends between the

  second end 30 and the pulley 20.

  If we consider the first section 40, we can see that, by the presence of a deflection roller 52, it is kept constantly in contact with the cylindrical roller 48 whatever its position around the axis. A3. However, as can be seen in particular by comparing Figures 2 and 4, depending on the position of the roller 48, the path that the cable must travel between the first end 28 and the pulley 20 is more

  i5 or less. The same is true for the second section 44.

  In this embodiment of the invention, it can be seen that the two ends 28, 30 of the cable 24 are fixed substantially at the same point and that this point is arranged in a plane P containing the axis A1 of the shaft 10 and the axis A3 of the motor 14. Thus, the two sections 40 and 44 remain permanently on one side or the other of this plane P. The roller 48, which is arranged between the two sections 40, 44, is therefore in contact with these two sections by two portions of its external cylindrical surface 50 which are

  substantially diametrically opposed.

  The two rollers 52, which deflect the path of each of the sections 40, 44 in the direction of the plane P, are arranged symmetrically on either side of the plane of P, substantially halfway between the ends 28, 30 and the pulley 20. In addition, it should be noted that their spacing is less

the diameter of the pulley 20.

  The cylindrical roller 48 acts on the first and the second section of the cable 24 in their portions which are between the end 28, 30 and the corresponding roller 52. The roller 48 acts on each section so as to stress the cable by moving it perpendicular to the plane P, beyond a joining straight line.

  the end 28, 32 and the corresponding roller 52.

  When the roller 48 occupies the position illustrated in FIG. 2, in which its axis A4 is at a maximum distance from the plane P, it can be seen that the path which the first section 40 must travel between the end 28 and the pulley 20 is maximum . On the contrary, the path that the second section 44 must travel is minimum. When the roller 48 rotates around the axis A3 anti-clockwise to reach the position illustrated in FIG. 3, it can be seen that the path of the first section 40 is reduced and that, on the contrary, the path of the second section 44 increases. Due to the symmetry of the system, the variations in path length for the first and second sections are

equal but inverse.

  As a result, the second section 44 is stressed in tension and tends to rotate the shaft 10 by an angle equal to half of its total angular travel from a first position

  extreme, counterclockwise considering the figures.

  By continuing the rotation movement of the roller 48 counterclockwise to the position illustrated in FIG. 4, the roller 48 continues to increase the path which the second section 44 must travel, and the shaft 10 continues its movement of counterclockwise rotation until reaching a second extreme position. On the contrary, when the roller 48 moves from its position illustrated in FIG. 4 to that illustrated in FIG. 5, but also from the position of FIG. 5 to that of FIG. 2, the path which the second section must travel 44 decreases while that which the first must travel increases so that the first section 40 is stressed in tension to control the return of the shaft 10 to its position first extreme position. It can therefore be seen that when the roller 48 makes a complete revolution around the axis A3, the shaft 10 performs a round trip between its two extreme positions. The total angular travel of the shaft 10 between its two extreme positions depends in particular on the distance separating the axes A3 and A4 from the motor 14 and the roller 48, from the diameter of the cylindrical roller 48,

and the diameter of the pulley 20.

  Due to the symmetry of the system, it is noted that whatever the position of the cylindrical roller 48, the total length of the path which the cable 24 must travel remains constant. Of the

  so it is possible to use an inextensible cable.

  However, as a variant, it is also possible to carry out the invention by providing that the roller 48 acts only on the first section 40 of the cable 24, the second end 30 of the cable 24 then having to be connected to elastic return means such as a helical tension spring for, on the one hand, keeping the cable 24 in tension in contact with the roller 48, the roller 52 and the pulley 20, and for, on the other hand, bringing the drive shaft 10 towards the second extreme position when the roller 48 passes from its position illustrated in FIG. 2 to its position illustrated in FIG. 4, moment during which the

  path of the first section 40 tends to decrease.

  Of course, in the embodiment illustrated in FIG. 1, the drive of the second drive shaft 12 of the wiping system is done symmetrically, the two

  cables 24, 26 being stressed by the same cylindrical roller 48.

  As shown in Figure 1, the wiping system is designed so that the two shafts 10, 12 rotate simultaneously in rotation about their axis in directions

  opposite to each other.

  However, it is possible to cause the two shafts 10, 12 to rotate simultaneously in the same direction, simply by providing that the two sections of one of the cables 24, 26 cross each other so that this cable describes an 8. There is schematically illustrated in Figures 6 to 9 a second embodiment of the invention in which the two drive shafts 10,12 are driven in their

  rotary scanning movement alternated by a single cable 24.

  In this embodiment, the drive section 36 of the cable 24 is composed not only of the two portions of the cable which wind around each of the pulleys 20, 22, but also of the part of the cable 24 which extends between these two portions. We can see that the axis A3 of the motor 14 is offset from the plane P containing the two axes A1, A2 of the two drive shafts 10, 12. If we consider two planes P1 and P2 perpendicular to each other and containing the axis A3 of the motor 14, the first plane P1 being parallel to the plane P containing the two axes A1, A2, it can be seen that the two fixed ends 28, 30 of the cable 24 are arranged respectively on either side of the P2 plan, but nearby

immediate from plan P1.

  Similarly, the first section 40 and the second section 44 each have their trajectory deflected by two deflection rollers 52 which are arranged respectively on either side of the plane P2, opposite the corresponding fixed end 28, 30 relative to this plane P2 and close to the plane P1. As in the first embodiment of the invention, the end attachment points 28, 30 and the deflection rollers 52 are positioned so that the portion of the cable 24 which extends between the two always remains in abutment the external cylindrical face 50 of the roller 48,

  whatever the position of the latter.

  As can be seen, the first section 40 and the second section 44 of the cable 24 are in contact with portions of the roller 48 which are diametrically opposed by

compared to axis A4.

  In the same way as that explained with reference to FIGS. 2 to 5, it can be seen in FIGS. 6 to 9 that when the roller 48 makes a complete revolution around the axis A3 of the motor, the wipers carried by the shafts drive, 12 perform a round trip between their two extreme positions. In this embodiment of the invention, the two drive shafts are driven in a rotation movement of the same direction, but it would be possible to obtain movements in opposite directions, by modifying the winding direction of the drive portion 36 around one

of the two pulleys 20, 22.

  FIG. 10 shows in third embodiment of the invention which is in reality an optimized variant of the second embodiment illustrated in FIGS. 6 to 9. In particular, the fixing points of the ends 28, 30 of the cable 24, as well as

deflection rollers 52.

  The two fixing points and the two rollers 52 are arranged so as to draw a trapezoid with four corners. More particularly, the ends 28, 30 of the first and second 11 sections are geometrically arranged at two opposite corners of the trapezoid. The two references 52 are arranged at the other two opposite corners. It should also be noted that the axis of

  rotation A3 of the motor 14 is arranged inside the trapezoid.

  Finally, it is preferably possible to arrange the axis of rotation A3 of the motor substantially at the intersection of the two

diagonals of the trapezoid.

  The wiping system according to the invention is therefore particularly simple to implement since it comprises a reduced number of elements. The cable or cables can have their trajectory adapted to take into account the environmental constraints linked to the presence of other members mounted nearby in the vehicle. In addition, these wiping systems allow the use of a rotary electric motor whose direction of rotation is constant, which makes it possible to reduce the cost as well as that of its control electronics, without

  use a rod and crank system.

Claims (13)

  1. Wiping system for a motor vehicle window, of the type in which at least one windscreen wiper is driven in a rotary sweeping movement alternated by a drive shaft (10) itself driven by a rotary motor (14) by means of a transmission mechanism (18),] 0 characterized in that the transmission mechanism (18) comprises a cable (24) of which a first end (28) is fixed and of which a section d drive (36) is wound without sliding around a pulley (20) which is integral in rotation with the drive shaft (10), and in that the i5 mechanism includes an actuator (48) which acts on a first section (40) of the cable (24) included between the first end (28) and the drive section (36), in a direction not parallel to the path of the first section (40) of the cable (24) between the point fixing the first end (28) and the pulley (20), to vary the length alternately r of the path of the first section (40), and in that the mechanism (18) includes means (44) for maintaining stretched the first section (40).   2. Wiping system according to claim 1, characterized in that the second end (30) of the cable is connected to elastic return means which maintain the cable in tension.   3. Wiping system according to claim 1, characterized in that the second end (30) of the cable (24) is fixed, and in that the mechanism (18) comprises an actuator (48) which acts on a second section (44) of the cable (24) between the second end (30) and the drive section (36), in a direction not parallel to the path of the second section (44) of the cable (24) between the fixing point of the second end (30) and the pulley (20), for varying the length of the path of the second section (44) in reverse to the variation in length of the first section. 4. Wiping system according to claim 3, characterized in that it comprises a single actuator (48) which   acts on the two sections (40, 44).   5. Wiping system, characterized in that it comprises io two wipers each driven by a drive shaft (10, 12), the shafts (10, 12) being secured respectively to a first (20) and d '' a second (22) pulley, and in that it comprises two   transmission according to any one of the claims   above which each drive one of the two trees (10, 12). 6. Wiping system according to claim 5, characterized in that the two transmission mechanisms   (18) have a common single actuator (48).   7. Wiping system according to any one of   Claims I to 4, characterized in that it comprises two   windscreen wipers each driven by a drive shaft (10, 12), the shafts (10, 12) being secured respectively to a first (20) and a second (22) pulley, and in that the section drive (36) of the cable (24) is wound without sliding around the two pulleys.   8. Wiping system according to any one of   previous claims, characterized in that the actuator   is a roller (48) which is rotated in one direction by the motor (14), and in that the roller (48) acts on the cable by a peripheral surface (50) which is eccentric with respect to   the axis of rotation (A3) of the motor (14).   9. Wiping system according to claim 8, characterized in that the roller (48) is cylindrical with an axis (A4)   parallel to the axis of rotation (A3) of the motor (A4).   10. Wiping system according to claim 9 taken   in combination with any of claims 3 to   8, characterized in that the first (40) and the second section (44) of the cable (24) cooperate with portions of the peripheral surface (50) of the roller (48) which are diametrically   opposite with respect to the axis (A4) of the roller (48).   11. Wiping system according to any one of   Claims 7 to 10, characterized in that the points of   fixing the ends (28, 30) of the first and second sections (40, 44) are geometrically arranged at the two opposite corners of a trapezoid at the other two corners of which are arranged return rollers (52) against which the first (40) and second (44) section. 12. Wiping system according to claim 11, characterized in that the axis of rotation (A3) of the motor (14) is   arranged inside the trapezoid.   13. A wiping system according to claim 12, characterized in that the axis of rotation (A3) of the motor (14) is arranged substantially at the intersection of the two diagonals of the trapezoid.