FR2926765A1 - DEVICE FOR PROJECTING A WASHING FLUID OF A GLASS OF A MOTOR VEHICLE AND A WIPING SYSTEM COMPRISING SAID PROJECTION DEVICE - Google Patents

Abstract

Device for dispensing and spraying a washing liquid on a window of a motor vehicle, said device comprising at least one liquid transport ramp (41) pierced with at least one hole (42a) for spraying washing liquid onto According to the invention, said transport ramp (41) further comprises at least one complementary projection means (42b) capable of projecting the washing liquid onto said window pane under a liquid pressure higher than a given pressure threshold. .Application to wiper systems for motor vehicles.

Description

DEVICE FOR DISPENSING AND SPRAYING A WASHING FLUID ON A GLASS OF A MOTOR VEHICLE AND WIPING SYSTEM COMPRISING SAID PROJECTION DEVICE

The present invention relates to a device for dispensing and spraying a washing liquid on a window of a motor vehicle. It also relates to a wiper system comprising said projection device.

The invention finds a particularly advantageous application in the field of wiper systems for motor vehicles, and more particularly in that of wiper systems comprising flat windscreen wiper blades, also known by the generic term Flat Blade. At present, the most used washing liquid spray devices consist of one or more nozzles placed on the hood of the vehicle. When the user activates the projection device by means of a control member located generally close to the steering wheel, a pump performs under a pressure of 2 to 4 bar the transfer of a certain amount of washing liquid from a reservoir up to the nozzles, the liquid arriving on the window to be cleaned, the windshield of the vehicle for example, in the form of jet or tablecloth. The disadvantage of these known projection devices is that they consume a fairly large amount of washing liquid, for several reasons. One of these reasons is the flow of a portion of the liquid sprayed out of the wiping area because the nozzles are not properly oriented or incorrectly adjusted. This fraction of liquid not participating in the cleaning is lost. It may also occur that liquid thrown by the sprinklers does not reach the windshield due to high wind or high vehicle speed, for example, which deflects the jet of liquid from its normal trajectory. or because the jets partially clogged with impurities scatter the jet or project it in a direction different from its nominal projection direction. To overcome these disadvantages and obtain a lower consumption of washing liquid, it is proposed dispensing devices and projection that are integrated into the wiper system itself. These integrated devices are in the form of at least one liquid transport ramp pierced with a plurality of projection holes over at least a portion of its length. The washing liquid is brought to the ramp by a feed pump connected to the liquid reservoir and is projected onto the surface of the glass through the projection holes. International Application No. WO20071000346 describes an embodiment of such a projection device where the transport ramps pierced with projection holes are arranged on both sides along the wiping blade of a wiper blade. flat ice compliant with Flat Blade technology. It will be readily understood that these distribution and projection devices with integrated ramps lead to a significant reduction in the consumption of washing liquid for the same cleaning result. Indeed, the liquid being sprayed directly on the glass, in the immediate vicinity of the wiper blade, exactly on the area to be wiped and in the same movement, no loss can occur by deviation or dispersion of the jet and the entire the amount of liquid spray is used by the wiper blade to clean the glass. The efficiency of these projection devices is therefore maximum. However, under negative temperature conditions, a layer of frost may be formed on the surface of the glass which, in order to be removed, requires a much greater amount of washing liquid than is usually used at positive temperatures to rid the glass. solid particles that can attach to it, such as mud splashes or crushed insect residues. To solve this difficulty, one could of course think of increasing the nominal flow rate of washing liquid projected on the glass, but this would be to the detriment of the advantage mentioned above of the integrated ramp projection devices in terms of economy. of liquid consumption under conditions of positive temperatures, which are the most frequent conditions. Also, an object of the invention is to propose a device for dispensing and spraying a washing liquid on a window of a motor vehicle, said device comprising at least one liquid transport ramp pierced with at least one spraying washing liquid on said window, which would project a larger quantity of liquid when the temperature outside the vehicle becomes, for example low (below 5 ° C) or negative, while maintaining a flow of liquid to a minimum necessary when the outside temperature is positive. This object is achieved, according to the invention, because said transport ramp further comprises at least one additional projection means adapted to project the washing liquid on said window under a liquid pressure higher than a given pressure threshold. . Thus, the projection device according to the invention makes it possible to project the washing liquid through the single projection hole (s) under a nominal pressure ensuring a minimum flow rate, and this as long as the outside temperature remains above a given threshold, for example the freezing temperature of water, ie 0 ° C. On the other hand, if the outside temperature falls below the aforementioned threshold of 0 ° C., the washing liquid can also be projected, in addition to the projection holes, through the complementary projection means, it is sufficient to bring about the pressure of the liquid to a value greater than the pressure threshold beyond which the complementary projection means is capable of projecting liquid. This pressure threshold is a characteristic quantity of the complementary projection means. The respective values of the nominal liquid pressure for the positive temperatures and the pressure threshold are chosen such that the pressure threshold is greater than the nominal pressure. An increase in liquid flow is thus obtained only for negative temperatures, in accordance with the object of the invention. According to a first embodiment of the invention, said complementary projection means comprises a perforation made through said transport ramp, said liquid pressure threshold being substantially equal to the opening pressure of said perforation. Perforation means an opening made without removal of material, for example by means of a needle passing through an elastomeric transport ramp. The notion of hole on the contrary implies a removal of material. At rest, the perforation is closed in the sense that its edges remain contiguous, a pressure force greater than a given threshold is necessary to separate them and thus open the perforation. According to a second embodiment of the invention, said complementary projection means comprises a complementary hole pierced through said transport ramp, and a closure means capable of closing said complementary hole under the action of a force of elastic return, said pressure threshold being defined by the pressure to be applied to said closure means to exert a force equal to said elastic return force. The invention also relates to a wiper system of a window of a motor vehicle, comprising a projection device according to the invention. In an application to window cleaning under different temperature conditions, the invention provides that the wiper system comprises a temperature sensor for determining the wash liquid pressure to be provided by at least one feed pump. depending on the temperature outside the vehicle measured by said sensor. This arrangement can be implemented in the application example cited above where it is desired to increase the amount of liquid spray when the temperature outside the vehicle is negative. In this case, depending on whether the outside temperature measured by the sensor is positive or negative, the liquid pressure supplied by the supply pump (s) must be less than or greater than the pressure threshold of the additional means. Advantageously, said transport ramp extends along a wiper blade 30 of the wiper system. In particular, said wiper blade is a flat broom. The invention further relates to a wiper blade comprising a projection device according to the invention.

The following description with reference to the accompanying drawings, given as non-limiting examples, will make it clear what the invention consists of and how it can be achieved. Figure 1 is a sectional view of a flat wiper blade comprising a liquid projection device according to the invention. Figure 2 is a side view of a transport ramp of the projection device of the figurel. Figure 3a is an operating diagram of a wiper system according to the invention to a feed pump. Figure 3b is an operating diagram of a wiper system according to the invention with two feed pumps. FIG. 4 is a graph giving the number of effective throwing orifices as a function of the outside temperature of the vehicle. Figure 5 is a sectional view of a transport ramp comprising a variant of the complementary projection means according to the invention. In Figure 1 is shown in section a wiper blade belonging to a wiper system of a motor vehicle window, windshield or rear window in particular. The wiper blade of FIG. 1 is produced in accordance with the flat blade or flat blade technology and, as such, has a longitudinal support 10 made of extruded semi-rigid plastic material in which is housed a metal rod 20 for stiffening, or vertebra, of curved shape, extending substantially over the entire length of the blade so as to create a distribution of pressure on the window as uniform as possible. The support 10 also includes a longitudinal claw 12 in which an elastomeric wiper blade 30 is inserted. As shown in FIG. 1, on the support 10 is assembled and fixed a device 40 for spraying a washing liquid of the vehicle window comprising one or two liquid transport ramps 41 which also extend along the length of the vehicle. wiper blade. These ramps 41 are pierced with orifices for spraying washing liquid on the window, generally referenced 42 in FIG. 1. It can also be seen on the particular embodiment shown in this figure that the projection device 40 is associated with an aerodynamic deflector 50 in the same molded elastomer part, reinforced by a longitudinal rib 13 of the support 10. FIG. 2 shows that the projection openings 42 of the transport ramps 41 are of two types, namely open projection holes 42a. permanently and additional projection means constituted in this embodiment by perforations 42b able to project the washing liquid on the vehicle window provided that the liquid pressure is sufficient, that is to say at least equal at a given pressure level. As already mentioned above, said perforations 42b are produced without removal of material, by laser in the example of the cross-cuts of FIG. 2 or by means of a cold needle. It is understood that, if the liquid pressure inside the ramp 41 is small, only the holes 42a open at all times are operational and let the liquid pass, while the perforations 42b remain closed, the pressure being below the threshold pressure necessary to overcome the stiffness of the elastomer and spread the edges of the perforations so as to allow the passage of the washing liquid. Note that the holes 42a are made by removal of material, by machining or by means of a laser or a heated needle. This configuration is suitable when the amount required for satisfactory cleaning of the glass is limited, especially to remove traces of mud or insect residues, under conditions of positive outside temperature. It is then expected from the ramp supply system 41 25 washing liquid that it provides the liquid under a pressure less than the opening threshold perforations 42b. When the outside temperature becomes negative or below a predefined threshold, the amount of washing liquid to be sprayed must increase to melt the layer of frost that may form on the glass. For this purpose, the pressure of the liquid in the ramp 41 is brought by the supply system to a value greater than the opening threshold of the perforations 42b, so that the flow of liquid through the perforations 42b thus opened is adds to the liquid flow through the holes 42a.

FIG. 3a illustrates a wiper system incorporating at least one ramp 41 provided with projection orifices 42a, 42b as just described with reference to FIG. 2. The ramp 41 is fed from a reservoir 62 of washing liquid via a pump 61 adapted to deliver the liquid under a first pressure Po, lower than the opening threshold Ps of the perforations 42b, and under a second pressure PI at least equal to the threshold P. The outside temperature T supplied, directly or indirectly, by a temperature sensor 70 installed on the vehicle is compared with a threshold temperature TS, the temperature 0 ° C of freezing water in the exemplary embodiment discussed herein. If the outside temperature T is greater than the threshold TS, the pump 61 is set to supply the washing liquid to the ramp 41 at a pressure equal to the first pressure Po. In this case, the liquid consumption is reduced. If the outside temperature T becomes lower than the threshold TS, an increase in the liquid flow is obtained by adjusting the operation of the pump 61 so that the pressure of the liquid is equal to the second pressure P1, greater than the threshold P. FIG. 3b shows a wiper system with two pumps 61a, 61b supply. A first pump 61a is intended to supply, like the pump 61 of FIG. 3a, a pressure Po lower than the threshold Ps of opening of the perforations 42b, when the external temperature T is greater than the temperature threshold Ts of 0 ° C. If the outside temperature T becomes lower than this threshold, a second pump 62a, called a booster pump, adds to the pressure Po supplied by the first pump 61a an overpressure iP = P1-Po, the pressure P1 being greater than the threshold Ps of opening perforations 42b. The graph of FIG. 4 gives, as a function of the external temperature T, the number of holes 42a effective in dashed lines, the number of effective perforations 42b in phantom, and the total number of effective orifices in solid lines. The reduction in the number of orifices effective at low temperatures is due to the increase in the viscosity of the washing liquid, which is particularly noticeable at the level of the furthest orifices.

Figure 5 is an alternative embodiment of the complementary closure means of the invention. According to this variant, the complementary closure means 42c comprises, on the one hand, a complementary hole 421c, similar to the holes 42a of FIG. 2, pierced through the transport ramp 41 and, on the other hand, a means 422c closing the hole 421c constituted, in the example of FIG. 5, by a tongue-like element of the wall of the ramp 41 adapted to be applied against the hole 421c under the action of a restoring force to the elastic nature of the material in which the ramp 41 is made.

When the liquid pressure exerts on the hole 421c a force greater than the restoring force, the element 422c deviates from its closed position and opens the hole 421c. The pressure threshold is in this case defined by the pressure to be applied to the shutter means to exert a force equal to said restoring force. When the pressure falls below the pressure threshold, the shutter element 422c closes on the hole 421c by an elastic hinge effect.

Claims (9)

1. Apparatus for dispensing and spraying a washing liquid onto a window of a motor vehicle, said device comprising at least one liquid transport ramp (41) pierced with at least one liquid projection hole (42a). washing on said window, characterized in that said transport ramp (41) further comprises at least one complementary projection means (42b; 42c) adapted to project the washing liquid onto said window pane under a liquid pressure greater than a threshold (Ps) given pressure. 2. Device for distribution and projection according to claim 1, wherein said complementary projection means comprises a perforation (42b) made through said transport ramp (41), said threshold (Ps) of liquid pressure being substantially equal to the opening pressure of said perforation (42b). A dispensing and splash device according to claim 1, wherein said complementary projection means (42c) comprises a complementary hole (421c) pierced through said transport ramp (41), and shutter means (422c). adapted to close said complementary hole (421c) under the action of an elastic restoring force, said pressure threshold (Ps) being defined by the pressure to be applied to said closing means (422c) for exerting a force equal to said elastic restoring force. 4. A dispensing device and projection according to claim 1, wherein, said transport ramp (41) has a alternation of hole (42a) of liquid projection and complementary projection means (42b; 42c). 5. A wiper system of a motor vehicle window, comprising a dispensing and projection device according to any one of claims 1 to 4. 5 A wiper system as claimed in claim 5, comprising a temperature sensor (70) for determining the wash liquid pressure to be supplied by at least one supply pump (61; 61a, 61b) as a function of temperature. exterior (T) to the vehicle measured by said sensor (70). The wiper system of one of claims 5 or 6, wherein said transport ramp (41) extends along a wiper blade of the wiper system. 10 The wiper system of claim 7, wherein said wiper blade is a flat mop. A windscreen wiper blade having a dispensing and splashing device according to any one of claims 1 to 4.