Wiper system for cleaning a vehicle windshield and method for operating the wiper system

Abstract

The invention relates to a wiper system (10) for cleaning a vehicle window (1), comprising a reservoir (12) for a cleaning medium (2), a pump (14) for drawing the cleaning medium (2) from the reservoir (12), and at least one line (20) for supplying the cleaning medium (2) from a pressure side (18) of the pump (14) to a spray device (32), wherein the spray device (32) is designed to spray the cleaning medium (2) onto the vehicle window (1) in the wiping area (28, 30) of at least one wiper blade (22, 24). According to the invention, a suction side (16) of the pump (14) is at least indirectly connected to a device (40) for supplying air, so that air can be drawn in by the pump (14) via the suction side (16) of the pump (14) in addition to the cleaning medium (2) in order to produce a foam-like mixture of the cleaning medium (2) and the air at the pressure side (18) of the pump (14).

Description

State of the art

[0001] The invention relates to a wiping system for cleaning a vehicle windshield with the features of the preamble of claim 1. Furthermore, the invention relates to a method for operating a wiping system according to the invention.

[0002] A wiper system for cleaning a vehicle windshield with the features of the preamble of claim 1 is known from DE 10 2014 118 184 A1 of the applicant. The known wiper system has a spray device for a cleaning medium, in which the cleaning medium is drawn from a reservoir on a suction side of the pump by means of a (feed) pump and conveyed to the at least one spray device via a pressure side of the pump and a fluid line. In order to prevent the spray device from freezing, particularly at low ambient temperatures, the known wiper system also has a device for generating overpressure downstream of the pressure side of the pump, with which pressurized air can be fed into the line serving to supply the cleaning medium to the spray device.

[0003] Another wiping system with the features of the preamble of claim 1 is known from WO 2014 / 198892 A1.

[0004] The reservoir for the cleaning fluid is usually located in the engine compartment of the vehicle and requires a certain amount of installation space. Furthermore, it is common practice to store, for example, five liters of cleaning fluid in the reservoir so that it does not need to be constantly refilled. Therefore, car manufacturers are looking for ways to reduce both the space required for the reservoir and, in particular, the weight or mass of the cleaning fluid while maintaining the same overall cleaning effect in practice.

[0005] Furthermore, from JP S56 63 538 A it is known to connect a suction side of the pump with a device for supplying air, so that the suction side of the pump draws in air from the suction side of the pump in addition to the cleaning medium, in order to provide a foamy mixture of the cleaning medium and the air at the pressure side of the pump.

[0006] From US 2009 / 0211605 A1 it is known to use compressed air-operated spray nozzles in car washes that can spray different cleaning media onto the body of a vehicle.

[0007] US patent 2013 / 0056497 A1 discloses a foam generation device in which a container for a liquid cleaning medium is foamed by introducing mechanically compressed air into a mixing chamber and discharged through a nozzle.

[0008] Furthermore, US patent 2017 / 0135531 A1 discloses a multi-functional pump that can both pump cleaning fluids and generate foam. To generate foam, liquid cleaning medium is mixed with pressurized air in a mixing chamber to create a foam.

[0009] Most recently, it is known from JP 2009040069 A to provide containers for compressed air or gas in a vehicle's windshield wiper system in order to create a cleaning foam by mixing it with a liquid cleaning medium, which can then be applied to a vehicle windshield. Disclosure of the invention

[0010] The inventive wiper system for cleaning a vehicle window with the features of claim 1 has the advantage that, in a structurally advantageous design, it is avoided that liquid cleaning medium is released from the air intake bore to the environment when the pump is not in operation via the suction side or the air intake bore.

[0011] Specifically, the teaching of the invention according to claim 1 proposes to design the wiping system such that a suction side of the pump is at least indirectly connected to a device for supplying air, so that air can be drawn in from the pump via the suction side of the pump in addition to the cleaning medium, in order to generate a foam-like mixture of the cleaning medium and the air on the pressure side of the pump, that the device for supplying the air has at least one air intake bore, and that the diameter of the at least one air intake bore has a diameter which, at atmospheric pressure, prevents the outflow of cleaning medium from the at least one air intake bore due to the surface tension of the cleaning medium from the at least one air intake bore.

[0012] Advantageous further developments of the wiping system according to the invention for cleaning a vehicle window are listed in the dependent claims.

[0013] In practice, this results in an inner diameter of at least one air intake bore between 0.1mm and 0.2mm, preferably about 0.15mm.

[0014] There are different possibilities regarding the arrangement of the at least one air intake bore. In one variant, the at least one air intake bore is located in the area of ​​an intake port of the pump, which is connected to the external environment of the reservoir. Air is thus drawn in from the external environment of the reservoir, i.e., from the engine compartment.

[0015] In an alternative arrangement of the at least one air intake bore, it is provided that the at least one air intake bore is located in the area of ​​a ventilation nozzle inside the reservoir. Such an arrangement has the particular advantage that any escape of cleaning medium from the air intake bore is not critical, since the escaping cleaning medium returns to the reservoir and is therefore not lost.

[0016] To prevent cleaning medium from being drawn in through an air intake bore located inside the reservoir, the latter variant is designed so that the vent nozzle opens into the reservoir above the level of the cleaning medium. This ensures that only air from the reservoir is drawn in, as desired.

[0017] To enable the pump to generate cleaning foam from the liquid cleaning medium and the aspirated air with minimal equipment complexity, the pump is designed to foam the cleaning medium and air, preferably by means of at least one vane element or similar device. Specifically, the pump is designed as a vane pump. Such a pump typically allows the formation of cleaning foam with only minor additional effort or modifications for the necessary air intake.

[0018] A further modification of the wiper system concerns the spray mechanism. This can be designed either such that the spray mechanism has at least one spray nozzle separate from the at least one wiper blade, or at least one spray nozzle integrated into the at least one wiper blade. The latter variant is also referred to by the applicant as the so-called "Aqua-Blade wiper blade".

[0019] A further variation of the invention relates to the possibility of using a cleaning medium for specific applications, which is, for example, in the form of a de-icing agent or a special cleaning agent, and which can then be used in addition to the normally provided cleaning medium or independently of it, depending on the application. In this case, an additional reservoir with a separate pump may be provided, through which the special cleaning medium is supplied to the wiper system or the spray device. Due to the inventive design of the wiper system with the particularly compact and lightweight reservoir, such a modification with the additional reservoir and pump can typically be implemented without requiring additional weight or installation space compared to a conventional wiper system in the engine compartment.

[0020] Finally, the invention also relates to a method for operating a wiper system as described above. The method is characterized by the use of a cleaning medium containing foaming agents. This improves or even enables the formation of the foam. In particular, it also ensures the foam-like consistency until it is sprayed onto the vehicle windshield.

[0021] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments and from the drawing.

[0022] This shows in: Fig. 1 a simplified representation of a wiper system according to the invention for cleaning a vehicle windshield using differently arranged spray devices, Fig. 2 a perspective view of a reservoir for cleaning medium equipped with a pump and an intake bore for ambient air, Fig. 3 a detail of the Fig. 2 in enlarged view in the area of ​​the air intake, Fig. 4 a perspective view of a modified storage container for the cleaning medium, in which the air intake is from an area inside the storage tank and Fig. 5 A schematic representation of a modified device for drawing in air using a pump.

[0023] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0024] In the Fig. Figure 1 is a simplified representation of a wiper system 10 for cleaning a vehicle window 1, in the illustrated embodiment a vehicle windshield. The wiper system 10 has a reservoir 12 for storing a liquid cleaning medium 2. Depending on its consistency or composition, the cleaning medium 2 may optionally contain a so-called foaming agent 3 to generate or ensure the formation of (cleaning) foam.

[0025] Preferably, a pump 14 is arranged inside the storage container 12 for drawing the cleaning medium 2 or the foaming agent 3 from the storage container 12. For this purpose, a suction side 16 of the pump 14 is in operative connection with the cleaning medium 2 or the foaming agent 3 in the storage container 12. A pressure side 18 of the pump 14 is connected to a line 20.

[0026] The wiper system 10 further comprises, by way of example, two wiper blades 22, 24, which are interchangeably attached to wiper arms 26 and which, in a manner known per se, generate a wiping area in the form of a wiping field 28, 30 when pivoting back and forth between a lower reversal position UT and an upper reversal position OT. Within the area of ​​the respective wiping field 28, 30, the cleaning medium 2 or the foaming agent 3 can be applied to the vehicle windshield 1 in the form of foam by means of a spray device 32, which is supplied with cleaning agent via the line 20, through at least one spray nozzle 34, 36. The spray nozzle 34, 36 can, for example, be arranged as a stationary spray nozzle 36 in the area of ​​the vehicle body or the engine hood of the vehicle, with each spray nozzle 36 then being assigned to a wiping field 28, 30.Alternatively, it can be provided that each wiper blade 22, 24 is assigned several spray nozzles 34 on at least one longitudinal side, which spray the cleaning medium 2 or the foaming agent 3 in the form of foam directly in front of the respective wiper blade 22, 24 onto the vehicle window 1.

[0027] As particularly evident from the Fig. As can be seen from Figures 1 to 3, the suction side 16 of the pump 14 is also at least indirectly connected to a device 40 for drawing in air. The device 40 is located in the Fig. In the embodiment shown in Figures 1 to 3, the device 40 is designed in the form of an air intake nozzle 42, the air intake bore 44 of which, opening outside the reservoir 12, has an (inner) diameter d for drawing in air between 0.1 mm and 0.2 mm, preferably about 0.15 mm. This design of the device 40 thus enables additional air to be drawn in via the suction side 16 of the pump 14, which, particularly in conjunction with the foaming agent 3, enables the pump 14 to form cleaning foam from the cleaning medium 2. For this purpose, it is particularly provided that the pump 14 has at least one element, such as a vane element or similar, to ensure the appropriate mixing of the air with the cleaning medium 2 and the foaming agent 3. In particular, the pump 14 may be designed in the form of a vane pump.The cleaning agent supplied to the spray device 32 is thereby formed in the form of a cleaning foam, which consists of the cleaning medium 2, possibly the foaming agent 3 and air bubbles.

[0028] Furthermore, it may optionally be provided that line 20 is equipped with an additional storage tank 50 with additional [unclear], in the Fig. 1 is connected to a pump not shown. The reservoir 50 may, for example, contain a special de-icing agent or other special cleaning agent.

[0029] The one in Fig. The facility shown in Figure 40 differs from the facility shown in Figure 40 according to the Fig. 1 to 3 by the fact that the air intake nozzle 42a with its air intake bore 44a draws in air from the interior 46 of the reservoir 12 above the level 47 of the cleaning medium 2 via a ventilation nozzle 45.

[0030] Finally, the in the Fig.The device 40 shown in Figure 5 comprises a pump 14, the drive shaft 52 of which has a section 54 with a cross-sectional reduction in the form of a flattened portion 55. In an axial subsection of the flattened portion 55, this flattened portion is radially surrounded by a first, elastic sealing element 56. Furthermore, the end of the drive shaft 52 is connected to a mixing element in the form of an impeller 58. The impeller 58 is arranged in the area of ​​an intake chamber 60, which is connected to the reservoir 12 via the suction side 16. The intake chamber 60 is hydraulically connected to an intermediate chamber 62 via the flattened portion 54. The intermediate chamber 62 is sealed to the drive shaft 52 by a further sealing element 64. The intermediate chamber 62, in turn, is connected to the air intake bores 44, 44a.If the drive shaft 52 of the pump 14 is not rotated, the sealing element 54 rests against the drive shaft 52, even in the area of ​​the flattened section 54, so that no connection is formed between the intermediate chamber 52 and the intake chamber 60. When the drive shaft 52 is rotated, however, a gap 66 is formed between the flattened section 54 and the sealing element 56. Air drawn in through the air intake bore 44, 44a enters the intake chamber 60 through this gap and is converted into foam by the impeller 58 together with the cleaning medium 2 drawn in via the suction side 16. This foam is then conveyed via the pressure side 18 of the intake chamber 60 into the line 20.

[0031] The wiping system 10 described so far can be modified or adapted in a variety of ways without deviating from the inventive concept. Reference symbol list 1 vehicle window 2 Cleaning medium 3 foaming agents 10 Wiper system 12 storage containers 14 Pump 16 Suction side 18 printed pages 20 Management 22 wiper blade 24 wiper blades 26 wiper arms 28 wiper field 30 wiper field 32 Spray device 34, 36 Spray nozzle 40 facilities 42, 42a Air intake manifold 44, 44a Air intake bore 45 ventilation nozzles 46 Interior Level 47 50 storage containers 52 Drive shaft Section 54 55 Flattening 56 Sealing element 58 impeller 60 Intake chamber 62 Intermediate chamber 64 Sealing element 66 column d diameter UT Reversal Position OT Reversal Position

Claims

[1] Wiper system (10) for cleaning a vehicle windshield (1), comprising a reservoir (12) for a cleaning medium (2), a pump (14) for drawing the cleaning medium (2) from the reservoir (12), and at least one line (20) for supplying the cleaning medium (2) from a pressure side (18) of the pump (14) to a spray device (32), wherein the spray device (32) is configured to spray the cleaning medium (2) onto the vehicle windshield (1) in the wiping area (28, 30) of at least one wiper blade (22, 24), characterized by, that a suction side (16) of the pump (14) is at least indirectly connected to a device (40) for supplying air, so that air can be drawn in by the pump (14) via the suction side (16) of the pump (14) in addition to the cleaning medium (2) in order to produce a foam-like mixture of the cleaning medium (2) and the air at the pressure side (18) of the pump (14), that the device (40) for supplying the air has at least one air intake bore (44; 44a), and that the diameter (d) of the at least one air intake bore (44; 44a) has a diameter (d) which, at atmospheric pressure, prevents the outflow of cleaning medium (2) from the at least one air intake bore (44; 44a) due to the surface tension of the cleaning medium (2) from the at least one air intake bore (44; 44a). [2] Wiping system according to claim 1, characterized by , that the diameter (d) of the at least one air intake bore (44; 44a) is between 0.1mm and 0.2mm. [3] Wiping system according to claim 1 or 2, characterized by , that at least one air intake bore (44) is arranged in the area of ​​an intake nozzle (42) of the pump (14) which has a connection with the surroundings of the storage container (12). [4] Wiping system according to claim 1 or 2, characterized by , that at least one air intake bore (44a) is arranged in the area of ​​a ventilation nozzle (45) inside the storage container (12). [5] Wiping system according to claim 4, characterized by , that the ventilation nozzle (45) opens above a level (47) of the cleaning medium (2). [6] Wiping system according to one of claims 1 to 5, characterized by , that the pump (14) is designed to froth the cleaning medium (2) together with the air. [7] Wiping system according to claim 6, characterized by , that the pump (14) is designed as a vane pump. [8] Wiping system according to one of claims 1 to 7, characterized by, that the device (40) has an intermediate chamber (62) which is connected to the at least one air intake bore (44; 44a), that the intermediate chamber (62) is penetrated by a drive shaft (52) of the pump (14) which extends into an intake chamber (60) for the cleaning medium (2) and is connected there to a mixing element (58), and that when the drive shaft (52) is rotated, a gap (66) can be formed between the intermediate chamber (62) and the intake chamber (60) so that air drawn in via the intermediate chamber (62) enters the intake chamber (60). [9] Wiping system according to claim 8, characterized by, that the drive shaft (52) has a cross-sectional reduction (55) in a connecting section between the intermediate chamber (62) and the intake chamber (60), and that the drive shaft (52) is radially surrounded in the area of ​​the cross-sectional reduction (55) by a sealing element (56) which is designed to seal against the drive shaft (52) when the drive shaft (52) is stationary and to form the gap (66) when the drive shaft (52) is rotated. [10] Wiping system according to any one of claims 1 to 9, characterized by , that the spray device (32) has at least one spray nozzle (34) integrated into the at least one wiper blade (22, 24). [11] Wiping system according to any one of claims 1 to 9, characterized by , that the spray device (32) has at least one spray nozzle (36) separate from the at least one wiper blade (22, 24). [12] Wiping system according to one of claims 1 to 11, characterized by, that an additional storage container (50) is provided for storing a de-icing medium or a special cleaning agent. [13] Method for operating a wiper system (10) designed according to any one of claims 1 to 12, characterized by , that in addition to the cleaning medium (2) a foaming agent (3) is used.

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