Abstract:
A wiper device includes a wiper arm that is mounted in driveable fashion and that bears a wiper blade, the wiper arm being formed by an essentially U-shaped profile part that surrounds the wiper blade at least partially. The front limb, which in the installed position points essentially in the direction of travel of the vehicle, forms a spoiler, and at least one air outlet opening is situated on the additional limbs. An air guide element, configured to pass through the profile part, is arranged at least in the inner area of the U-shaped profile part.

Description:
FIELD OF THE INVENTION 
   The present invention relates to a wiper device, in particular for windshields of motor vehicles. 
   BACKGROUND INFORMATION 
   Conventional wiper devices may have a wiper arm that is formed by a U-shaped profile part. Here the limb that, in the installed position, points in the direction of travel of the vehicle may form an integrated spoiler, and air outlet openings situated on the additional limb and/or on the back. Such a wiper arm is, for example, described in French Published Patent No. 2 632 897. 
   However, the spoiler and the air outlet opening may not prevent the occurrence, at higher vehicle travel speeds, of lifting forces that counteract the pressure force with which the wiper blade, fastened on the wiper arm, may be pressed onto the windshield. 
   SUMMARY OF THE INVENTION 
   A wiper device according to the present invention involves air guide elements that may be situated in the interior of the profile part, e.g. along the width of the wiper arm, to produce a course of the flow of the travel wind, which may effectively increase the pressure force of the wiper arm at high speeds and at the same time eliminate disturbing wind noises, without causing an optically disturbing effect and without significantly increasing the cost of the wiper arm. 
   If the air outlet openings are situated in the rear limb, facing away from the spoiler, of the U-shaped profile part, then these openings may be seen only from the interior of the vehicle, and may nonetheless be made sufficiently large to produce a sufficient downforce, and thus a sufficient pressure force. 
   If an air guide element protrudes beyond the limb of the U-shaped profile part, sufficient air may enter into the wiper arm for the production of the downforce. For example, the air guide elements may be situated in such a manner that they form a funnel-type inlet in the area of the lower spoiler edge. 
   In addition, the protruding air guide element may have a soft rubber lip, in order to prevent damage or noise in case of a possible contact between the vehicle windshield and the air guide element. In this manner, a particularly small spacing from the vehicle windshield may be achieved, thus potentially achieving a more desirable course of the flow. 
   If the air guide elements are situated in such a manner that the flow-through cross-section in the inflow area is smaller than it is in the outflow area, a suction effect may be achieved through the travel wind. 
   This effect may be further strengthened if, in the installed position, the air guide elements are closer to the windshield in the inflow area than in the outflow area. 
   A desirable course of the flow may be achieved if the air guide elements are situated in such a manner that the air flowing through is accelerated, so that a slight suction effect arises in the direction of the windshield. This airfoil-type effect may increase the wiping result significantly, particularly at high speeds. 
   In addition, at least one air outlet opening may be situated in the center limb of the U-shaped profile part, because in this manner the flow cross-section in the outflow area may be further increased. 
   If an air outlet opening is situated in the limb facing away from the spoiler, and another one is situated in the center limb, then almost any course of the flow may be achieved inside the U-shaped profile, and thus inside the wiper arm. 
   If, in addition, the air guide elements are fashioned as an injection-molded part, they may be manufactured economically, and they may increase the weight of the wiper device only marginally. In addition, these injection-molded parts may also be replaced easily in case of destruction. 
   The air guide elements may be clipped into the profile part, in order to enable completion of a rapid installation and rapid exchange, if for example damage has occurred. 
   The air guide element may be glued into the profile part, in order to obtain a positively locking, smooth connection, and in this manner to avoid the development of disturbing noise. 
   The air guide element may have a projection for the guiding of the wiper blade, through which the relative position of the wiper blade to the air guide element may be maintained. 
   The wiper blade may be fashioned as a flat-beamed wiper blade. The overall constructive height between the wiper arm, the spoiler and the wiper blade may be reduced to a minimum in this manner, because an expensive clip construction that may undesirably affect the air flow may not be required between wiper blade and profile part. 
   In addition, a funnel-type or double-funnel-type channel may arise between the air guide elements, in order to achieve an optimal course of the flow. In the case of a double-funnel-type channel, the air inlet openings and the air outlet openings may be larger than the center of the channel. 
   The wiper arm according to the present invention may achieve a desirable course of flow, in particular at high flow speeds, via the situation of an air guide element in the interior of the U-shaped profile part. 
   At least one air guide element may be borne by the wiper blade itself, and may be fastened thereto. In this manner, the flow may strike the wiper blade itself and produce an additional pressure force that presses the wiper blade onto the windshield. 
   The profile part may have an air flow opening in the area of its front limb, in which an air guide element borne by the wiper blade may be received. In this manner, the spoiler of the wiper blade/wiper arm combination may be formed equally by the wiper blade and by the wiper arm, resulting in a more uniform distribution of pressure force. 
   The air guide elements borne by the wiper blade may terminate approximately flush with the front limb, so that an essentially flat spoiler surface results. 
   In order to increase stability, in particular against torsional flexing, a plurality of air flow openings may be provided along the longitudinal extension of the wiper arm. In this manner, webs may arise between the air flow openings, which improve the rigidity of the wiper arm. 
   Nozzles may be provided in the interior of the profile part for the exit of cleaning fluid. Larger, e.g. heatable, nozzles may be arranged in particular in the area of the rear limb, in which the nozzles disturb only slightly the flow of air through the air guide elements positioned in front of them. 
   A wiper blade according to the present invention may achieve desirable air flow characteristics by having the back of the blade bear at least one air guide element that works together with an upper air guide element situated on or in the wiper blade. In particular, due to the direct air flow on the wiper blade, not only may this blade be pressed against the windshield indirectly via the wiper arm, but also the wiper blade itself may be so pressed. 
   In this context, the lower air guide element, borne by the back of the blade, may be able to pass through the profile part of the wiper arm, in particular through its front limb. In this manner, it may be possible to achieve a flat spoiler upper surface on the front limb of the profile part, and nonetheless to have air flow immediately against the wiper blade. 
   The wiper blade may bear a plurality of air guide elements along a longitudinal extension, since in this manner the stability of the wiper arm may not be limited. 

   
     BRIEF EXPLANATION OF THE DRAWINGS 
       FIG. 1  shows a wiper device according to the present invention in a perspective view. 
       FIG. 2  shows a wiper arm of a wiper device according to the present invention in a perspective view. 
       FIGS. 3 to 8  show sections through wiper arms of a wiper device according to the present invention in different variations. 
       FIG. 9  shows a wiper blade having air guide elements in a perspective view. 
       FIG. 10  shows a detail of the air guide element from  FIG. 9 . 
       FIGS. 11 to 16  show sections through a wiper arm with wiper blade. 
       FIG. 17  shows an inventive wiper arm having a wiper blade, in a perspective view. 
       FIG. 18  shows wiper arm and wiper blade according to  FIG. 17  after assembly. 
       FIGS. 19 to 21  show cross-sections through a wiper arm with wiper blade according to  FIG. 18 . 
       FIGS. 22 to 25  show cross-sections through a wiper arm with wiper blade according to  FIG. 18 , but with nozzles and various channels. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a wiper device  10  in a perspective view. This device has a motor  12  that drives, via a rod  14 , two wiper arms  16 , each bearing at its end a wiper blade  18 . Wiper blade  18  is fastened on wiper arm  16 , approximately parallel to the longitudinal extension thereof, and is partially surrounded by wiper arm  16 . Of course, it may also be possible for wiper blade  18  to be surrounded completely by wiper arm  16 . Here, wiper blade  18  is fashioned as a flat-beamed wiper blade. 
   As a part of a motor vehicle, wiper device  10  is fastened to the body thereof, and causes wiper blade  18  to slide over windshield  20 . During travel operation of the motor vehicle, the travel wind causes a flow of air, indicated by flow arrows  22 . 
     FIG. 2  shows a wiper arm  16  of a wiper device  10  according to the present invention, in a perspective view. The air flow direction is here again represented by flow arrow  22 . Wiper arm  16  is essentially made up of a U-shaped profile part  26  that is chamfered on the side facing the flow of air to form a spoiler. At the ends of its longitudinal extension, fastening elements  24 , in particular hooks and/or eyes, are arranged for fastening to rod  14  and to wiper blade  18 . On the side facing away from the flow of air, air outlet openings  40  are situated such that they are separated from one another by webs  25 . In an inner area  34  of profile part  26 , air guide elements  36 ,  38  are clipped in as a one-piece injection-molded part, which is represented in the drawings by broken lines. This injection-molded part is shown more precisely in cross-section in  FIGS. 3 to 8 . 
   Along its longitudinal extension, side walls  29  are situated between upper and lower air guide element  36 ,  38 ; these walls continue individual air outlet openings  40  of profile part  26  in the interior of air guide elements  36 ,  38 . On the side facing the flow, these side walls  29  are brought together in pair-by-pair fashion, and may prevent flow turbulences at webs  25  situated between air outlet openings  40 . In addition, they may increase the stability of the injection-molded part. 
     FIG. 3  shows a cross-section through the wiper arm of  FIG. 2 . Profile part  26  of wiper arm  16  has a back  30 , from which the two limbs extend laterally. The limb facing the flow of air is designated in the following as front limb  28 , and the limb facing away from the flow of air is designated rear limb  32 . Here as well, the flow of air is indicated by flow arrow  22 . 
   In the interior area  34  of U-shaped profile part  26 , air guide elements  36 ,  38  are situated, which partially also extend beyond inner area  34  of profile part  26 . Underneath profile part  26  a wiper blade  18  is shown, fashioned as a flat-beamed wiper blade. Air from inner area  34  of profile part  26  may flow out through air outlet openings  40 , situated in its limb  32  facing away from the flow. 
   In this context, upper air guide element  36  is situated in such a way that it extends from the lower edge of front limb  28 , facing windshield  20 , to the upper edge of air outlet opening  40 . Lower air guide element  38  projects from the lower edge of air outlet opening  40 , over wiper blade  18  and beyond profile part  26 , in the manner of an airfoil, so that a funnel-type air inlet opening  42  arises. In this manner a nozzle effect arises between air inlet opening  42  and air outlet opening  40 , which may strengthen the pressure force with which wiper arm  16  presses wiper blade  18  onto windshield  20 . At their end, air guide elements  36 ,  38  adjoin the air outlet openings in flush fashion, so that as little turbulence may be formed in this area as possible. 
   As shown in  FIG. 4 , air guide elements  36 ,  38  may also be fashioned such that they form a smooth, rounded-off transition with additional limbs  30 ,  32  in the area of the edges of air outlet opening  40 . 
   Front limb  28 , which forms the spoiler, may be shaped in convex fashion or, as shown here, in concave fashion. 
     FIG. 5  shows how lower air guide element  38  has a flow element  44  that extends from the lower side of lower air guide element  38  to the lower edge of rear limb  32 , in order to avoid undesirable flow characteristics such as turbulences in this area, without having an adverse effect on the flow to air outlet opening  40 . Of course, lower air guide element  38  may also be fashioned at its rear side in such a manner that no hollow space arises between flow element  44  and air outlet opening  40 . 
   In  FIG. 6 , lower air guide element  38  is lengthened at its side facing the flow by a soft rubber lip  46 . Here this rubber lip  46  is injection-molded onto the lower air guide element over a projection  48 , e.g. in a multicomponent injection-molding method. Here rubber lip  46  is oriented approximately perpendicular to windshield  20  and approximately parallel to the mid-axis of wiper blade  18 , but it may also have a knee  52 , and its cross-section may taper downwards. 
     FIG. 7   a  shows a variation of a wiper arm according to the present invention. Here U-shaped profile part  26  has, on its side facing the flow, a concave curvature, the lower edge of front limb  28  lying more closely on windshield  20  than the end, facing the flow, of lower air guide element  38  and the lower edge of rear limb  32 . Here, air outlet opening  40  is situated in back  30 , and the two air guide elements  36 ,  38  are correspondingly guided in the direction of back  30 . 
   In addition, in  FIG. 7   a  a parallelogram of forces is shown as it arises through interior air guide elements ( 36 ,  38 ). Due to the acceleration, air that flows through air guide elements ( 36 ,  38 ), which are fashioned as funnel-type channels, exerts a normal force (FN) perpendicular to the surface of lower air guide element ( 38 ). This is decomposed into a pressure force (FD) that presses wiper blade ( 18 ) in the direction of windshield ( 20 ), and a horizontal force (FH) that pushes wiper blade ( 18 ) over windshield ( 20 ). 
   As shown in  FIG. 7   b,  lower air guide element  38  in inner area  34  of profile part  26  may be situated such that wiper blade  18  is partially covered in terms of flow, so that only a small amount of air flows through area  54  over wiper blade  18 . 
   In  FIG. 8   a,  a variation of the exemplary embodiment from  FIG. 7   a  is shown. Besides air outlet opening  40  in back  30 , an additional air outlet opening  40  is situated in rear limb  32 . In order to prevent eddies between upper and lower air guide element  36 ,  38  in the area of air outlet openings  40 , a center wedge  56  is situated between these, ensuring a laminar course of the flow in the direction of the two air outlet openings  40 . This center wedge  56  is fashioned as an approximately triangular wedge, whose foot extends from the upper edge of rear air outlet opening  40  up to the rear edge of upper air outlet opening  40  situated in back  30 , and terminates flush with these edges. 
     FIG. 8   b  shows a further variation. As in  FIG. 8   a,  wiper arm  16  has two air outlet openings  40 , but, as is also the case in  FIG. 3 , lower air guide element  38  protrudes beyond the edge of front limb  28 , so that wiper blade  18  is covered almost completely by lower air guide element  38 , and forms a funnel-type air inlet opening  42 . 
     FIG. 9  shows a wiper blade  18  according to the present invention in a perspective view. Here lower air guide elements  38  are fastened not to wiper arm  16 , but rather to wiper blade  18 . 
   As already shown in  FIG. 8   b,  wiper blade  18  is essentially made up of a wiper blade element  58  whose blade back  60  is reinforced by a spring strip  62 . Lower air guide elements  38  are fastened, e.g. clipped on, to spring strip  62 . These guide elements may in principle also be fastened to wiper blade element  58  in the region of blade back  60 , or may be formed in one piece from wiper blade element  58  in the extruder. Moreover, spring strip  62  may be omitted. This may for example be achieved through a corresponding rubber mixture in the area of blade back  60  of wiper blade element  58 . 
   In  FIG. 10 , lower air guide element  38  may be seen as it is clipped on to spring strip  62 . This air guide element  38  is made up of a plate, on which wedge-shaped projections  64  that come to a point against the direction of flow are situated. Sidewalls  29  of wedge-shaped projections  64  are formed in such a manner that an optimal course of the flow of the entering air is achieved in the direction of air outlet openings  40  of wiper arm  60 . 
     FIG. 11  shows a cross-section through such an air guide element  38  having a wiper arm  16 . Air guide element  38  is clipped on to spring strip  62  in the region of blade back  60  of wiper blade element  58  by clip elements  62 . Of course, air guide element  38  may also be fastened to blade back  60  by gluing, locking, or ultrasound imprinting. The section shown here is situated in the area of air outlet opening  40 , as shown in  FIG. 10 . 
   On the edge of air outlet opening  40  facing the wiper blade, air guide element  38  has a deflecting edge  66  in order to improve the course of the flow. Through this, the deflection of the flow of the travel wind occurs at wiper blade  18 , and not at wiper arm  16 , so that a lifting off of wiper blade  18  may be avoided. 
   In  FIG. 12 , the same cross-section is shown as in  FIG. 11 , but in an area in which wiper arm  18  has no air outlet opening  40 . Air guide element  38  here extends up to back  30 , and divides the air stream through sidewalls  29  into two parts, so that the flow may escape through air outlet openings  40 . 
     FIG. 13  shows a variation of the system from  FIG. 11 . Air outlet opening  40  is located in the area of back  30  of wiper arm  16 , and lower air guide element  38  is shaped in such a manner that the air stream of the travel wind is deflected in the direction of air outlet opening  40  in back  30 . 
   Corresponding thereto, in  FIG. 14  the area of the wiper arm without air outlet opening  40  is shown. Here, air guide element  38  is essentially box-shaped, and seals the interior of wiper arm  16 . 
     FIG. 15  shows a development of the system shown in  FIG. 11 . In addition to lower air guide element  38 , fastened to wiper blade  18 , here an upper air guide element  36  is fastened in wiper arm  16 . This may for example be realized through a clip connection. In this manner, the air stream is deflected in the direction of air outlet opening  40  in a better manner, lower in turbulence. 
   In  FIG. 16 , wiper arm  16 , having upper air guide element  36 , is shown for the area in which no air outlet opening  40  is provided. Upper air guide element  38  is displaced upward, in the direction of wiper blade  18 , and almost touches the upper edge of lower air guide element  36 , which is raised at this point, and divides the flow towards the sides. 
     FIG. 17  shows a further variation of inventive wiper arm  16 , having a wiper blade  18 , in a perspective view. 
   Wiper arm  16  is essentially made up of an essentially U-shaped profile part  26 , to which wiper blade  18  may be coupled. Wiper blade  18  has, in the area of its blade back  60 , air guide elements  38  that are fashioned such that they penetrate into the interior of profile part  26  when wiper arm  16  is connected with wiper blade  18 . In order to increase the pressure force with which wiper blade  18  is pressed onto windshield  20 , front limb  28  of profile part  26  has air flow openings  70 , into which air guide elements  38  of wiper blade  18  penetrate in the assembled position, and forms an essentially smooth surface with front limb  28 . This is shown in  FIG. 18 . 
   In this context, the height of lower air guide elements  38  fastened to wiper blade  18  is determined by the geometry of wiper arm  16 . Typically, the interior height H in the area of the end of wiper blade  18 , covered by wiper arm  16 , is greater than the exterior height h in the area of the fastening of wiper blade  18  to wiper arm  16 , or even edge height h′ at the end, facing away from wiper arm  16 , of wiper blade  18 . 
     FIG. 19  shows a section through wiper arm  16  having air guide element  38  from  FIG. 18 . Wiper arm  16  has air flow opening  70  in the area of its front limb  28 . Air guide element  38 , fastened in the area of blade back  60 , enters into this air flow opening  70 , so that an essentially smooth surface results. 
   For this purpose, lower air guide element  38  essentially has an inverted V shape. On its side facing the flow, air guide element  38  has a knee  72  to which a stilt  74  is connected. Clip element  68 , which connects air guide element  38  with spring strip  62  of blade back  60 , is then situated on this stilt. Through stilt  74 , there results a smooth curve between front limb  28  and the air flow surface of air guide element  38 . 
   Wiper blade  18  may be moved in the vertical direction inside profile part  26  of wiper arm  16  in order to compensate different geometries of windshield  20 . In order to enable this lifting movement, air flow opening  70  of wiper arm  16  extends beyond back  30  of profile part  26 . This is again shown in  FIG. 20 . 
     FIGS. 21   a  and  21   b  show a variation of the present invention. Wiper arm  16  may also be of flat construction in the areas of stability, between air flow openings  70 , and in cross-section may extend approximately parallel, or with only a slight convex curvature, to blade back  60  ( FIG. 21   b ). In this embodiment, air guide elements  38  then protrude from wiper arm  16  along the longitudinal extension of wiper arm  16 , in comb-type or tooth-type fashion ( FIG. 21   a ). 
   In  FIG. 21 , the area of wiper arm  16  is shown in which no air flow opening  70  is provided. In this area, air guide element  38  is fashioned only in degenerate form, i.e. only as a plate that is situated approximately parallel to spring strip  60  and that functions only to aid the stability of the system. 
   In this area, there results a hollow space  76  inside the wiper arm that is suitable for the situation of nozzles  78  through which cleaning fluid may be sprayed onto windshield  20 . This is shown in  FIG. 22 . 
   Here, as indicated in  FIG. 22 , nozzles  78  may either spray directly out of wiper arm  16 , or, as shown in  FIG. 23 , may spray onto windshield  20  through a spray opening  80 . In the areas in which air guide element  38  passes through air flow opening  70 , this guide element may also be fashioned, by an additional knee  82 , in such a manner that a cleaning fluid channel  84  may be situated here as well. A flow supply line for a nozzle  78 , a cleaning fluid channel heating unit, or a nozzle  78  itself, may be arranged here, as shown in  FIGS. 24 and 25 . In particular, nozzles  78  having a non-return valve, may have a large constructive shape.