EP2777056B1 - Illuminated, water- and dust-proof switching element - Google Patents

Description

The invention relates to an illuminated, water and dust-proof switching element, for converting a linear movement of a key in an electrical switching signal, with a housing and a housing axially displaceable in the housing by a stroke between two repositories cap, which is provided with an outwardly sealing protective membrane , which is executed by means of multi-component injection molding of a pliable plastic material and preferably for use outdoors in vehicle construction for switching and / or display of operating states of electrical assemblies.

Illuminated, water and dust-proof switching elements are already used in vehicle construction in a wide variety of variants and are thus well known.

The EP 2 175 462 A1 describes a sealed switch for converting a linear movement of a key into an electrical switching signal, comprising a housing which supports the key axially movably held therein, a shutter fixedly connected to the key, and a shutter covering and outwardly sealed cap, which consists of a pliable plastic material, the interior of the switch should be encapsulated air and waterproof and the switching characteristic when pressing the button should as possible be made uniform over the entire stroke. Characterized in that the cap is under bias, since the diaphragm is curved dome or hemispherical outward against the direction of movement of the switch, a uniform switching characteristic is generated, because immediately upon actuation of the protective cap is already pressed from its initial position. While the protective cap and the cover are moved in the direction of the switching contact, no differently sized actuating forces are applied, since the protective cap is moved between an upper and a lower extension point, so that no additional due to overstretching of the protective cap resulting restoring forces occur. Furthermore, there is a joint-free curved surface of the protective cap, so that dirt does not fit and also can be wiped off in a simple manner. Furthermore, the cap due to the present bias no projections, beads or the like, which can serve as an attachment for dirt particles.

From the DE 10 2008 034 046 A1 An electrical switch is known.
The electrical switch is located in a housing provided with an opening. Inside the housing is a contact system and on the housing is at least partially projecting from the housing actuator arranged in the manner of a rocker for the switching action on the contact system. A bellows-type seal is attached to the end of the actuator and the other end to the housing in such a way that the seal substantially covers the opening. The actuator consists of two parts, an inner and an outer rocker, wherein the seal between the two parts is clamped and thus integrated in the actuator.

The DE 37 37 119 A1 relates to a Kurzhubdrucktaster in which a disc-shaped probe element acts on an elastic contact member, which indirectly or directly against a short stroke Counter contact member is resiliently depressible and thereby connects the poles of a separate circuit with each other.

On the contact side, a central reinforcement is formed on the elastic probe element, to which a biegelastic contact disc made of conductive material is attached coaxially, which holds from the edge of the central reinforcement radially outward distance from the plane of the key element and thereby at a short distance over a plurality of pole pairs the circuit to be closed, wherein the pole ends of the pole pairs form a plane which is parallel to the plane of the contact disc in the neutral position of the probe element. The flexurally elastic contact disc facing pole ends of the pole pairs and a circular arranged the vertical axis of the flexurally elastic contact disc such that follow in succession in rows one after another positive poles to negative poles.

Due to the circular arrangement of the contacts around the center of the elastic sensing element arranged central reinforcement and the contact disc central illumination of the switching element is not possible. In the application to be tested, the contacts are arranged square in a symmetrically constructive construction inside the switching element, whereby the lighting (LED) and the button can be positioned exactly in the middle. As a result, not only a peripheral edge-shaped but a central illumination of the switching element is possible. A pressure equalization follows here by a meander-shaped venting channel in the housing and not by a vent hose, which is highly elastic, closed on one side and is projecting in a cavity of the probe housing.

In contrast, the vent channel is open to the outside, so that a pressure equalization between the inner and the outer ambient conditions can take place, which is in the DE 37 37 119 A1 not possible.

The EP 1 233 434 A2 relates to a pushbutton structure for electrical, electronic and / or mechanical applications and at least one pushbutton component, which is injection molded or molded together with an elastic edge protection component and thus connected in a fluid-tight manner to the printer key structure.

The DE 35 19 872 A1 describes a disc switching pressure initiator. The disc surface switch of the initiator has a translucent actuator disc made of flexible material, on the back of a contact plate made of relatively rigid material with a relation to the actuator disc smaller diameter by means of a double-sided connecting foil is attached to a substantially smaller diameter compared to the contact board.

Both in centric and eccentric actuation of the actuating disk thus a switching signal triggering contact between the contact board and printed circuit board is generated safely.

The DE 10 2008 015111 B3 relates to a liquid-protected control element. This consists of at least one control knob and a printed circuit board, wherein one side of the circuit board completely or partially covering liquid-tight guide plate with at least one recess through which the control knob is connected to the circuit board, a recess in the guide plate rotating wall extending in the direction of the control knob extends and at least one drain, which dissipates the guide plate meeting liquid on the opposite side of the circuit board.

The control knob usually protrudes out of a housing and / or through a panel. Liquid can enter through the resulting gaps.

In order to prevent the liquid from flowing onto the printed circuit board and the ribbon elements arranged thereon, a guide plate is provided which allows the liquid / moisture to flow away from the printed circuit board.

Although the control element is protected against liquids, it is not waterproof and dustproof. At temperatures in the minus range, the penetrating liquid can freeze and thus lead to failure of the operating element.

Based on the prior art, the object of the invention is to develop a switch of the type mentioned in such a way that it can be used outdoors, a robustness against external Influences, such as freezing, etc., is provided with a pressure compensation element and in the installed state has a sealing effect also to the fastener out. Furthermore, the switching element in the installed state should have no visible gap to the fastener to protect against dirt, sand, snow or frost.

According to the invention the object is achieved by the features of claim 1.

The switching element is characterized in particular by its simple and compact design and is both opener as well as NO contact switch applicable. Due to the small and compact design also a minimal weight of the switching element is realized.

Further advantageous embodiments of the invention will become apparent from the dependent claims and from the following embodiment.

Figur 1

- eine perspektivische Darstellung des Schaltelements

Figur 2

- eine Explosionsdarstellung des Schaltelements mit Einbaublende

Figur 3

- Schnitt durch das Schaltelement mit Einbaublende

Figur 4

- Schnitt durch das Schaltelement mit Einbaublende

Figur 5

- perspektivische Darstellung der Schutzkappe

Figur 6

- Schnitt durch das Schaltelement mit Einbaublende

Reference to an embodiment of the invention will be explained in more detail. Show it

FIG. 1

- A perspective view of the switching element

FIG. 2

- An exploded view of the switching element with mounting plate

FIG. 3

- Section through the switching element with mounting plate

FIG. 4

- Section through the switching element with mounting plate

FIG. 5

- perspective view of the protective cap

FIG. 6

- Section through the switching element with mounting plate

The FIGS. 1 and 2 show a perspective view and an exploded view of the switching element. 1
In principle, the switching element 1 is composed of the components: cap 2, end stop 3, guide 4, silicone mat 5, printed circuit board 6, pressure compensation element 7, contacts 8, housing 9 and frame 10.

In the housing 9, which is preferably made of a plastic injection molded part, four contacts 8 are arranged outwardly next to each other and square by a deflection into the interior of the housing. The square arrangement allows inside the switching element 1 a symmetrically constructive construction, the LED for lighting and the button can be positioned exactly in the middle. The contacts 8 are each formed in pairs as equal parts. As a result, a reduction of the tool and handling expenses can be achieved. The contacts 8 form a meandering structure as a result of the deflection in the overmolded area, whereby a mechanical anchoring is achieved as protection against Steckdrückdrückfestigkeit in the housing 9 and an extension of the creepage distance at water inlet. At the same time, in this area of the encapsulation, a bonding agent can be applied circumferentially to the contacts 8, whereby a media-tight encapsulation is possible. The contacts 8 are contacted by means of a plug connection, although other industry-standard known connection techniques can also be used. In the inner region of the housing 9, the pressure compensation element 7 ( FIG. 3 ) , which is fixed media-tight by means of hot or ultrasonic welding. Via a meander-like venting channel 13 in the housing 9, which is open to the outside, the pressure equalization between the interior of the switching element 1 and the external environmental conditions can take place. In interaction with the frame 10, which is mounted on the housing 9 and at the same time forms a protective cover for the vent channel 13, the pressure compensation element 7 is protected from damage by external external influences. Due to the structurally symmetrical structure, a second pressure compensation element 7 or alternatively a volume compensation element, for example in the form of a silicone membrane, can be fastened on the opposite side, which compensates for the volume to be compressed on actuation of the switching element 1 due to the hermetic seal and thus the otherwise damping effect counteracts the air compression and thus optimizes the haptic properties.

The housing 9 is made in one piece with integrated connector tray 14, which is suitable for receiving a watertight plug.
The housing 9 ( FIG. 4 ) has at least three guide grooves 15 which correspond to the guide contours 16 of the guide 4. For the realization of a short installation depth and compact design with the longest possible leadership, the guide grooves 15 in the housing 9 are structurally designed so that the connector tray 14 for receiving the waterproof plug protrudes into the interior of the switching element 1 and the guide grooves 15 outside dive on the connector tray over. Another advantage of this constructive solution is that the receiving area for the pressure compensation element 7 and the circuit board 6 is close to the upper opening of the housing 9. As a result, an optimal hot or ultrasonic welding of the pressure compensation element 7 and a good connection to the circuit board 6, for example by means of solder connection, given. For the attachment of the pressure compensation element 7 and alternative bonding techniques, eg gluing, possible.

The guide 4 has at least three solid end stops 18, which are formed in the form of a T-profile above the guide contours 16 and meet upon actuation of the switching element 1 in the direction of actuation on the end stops 17 in the housing 9 and so depict the end position of the switching element 1. Abuse forces of at least 250 N in the direction of actuation can be absorbed by means of these solidly executed limit stops of the switching element 1, without loading the switching contacts and without damaging the components of the switching element 1.

The switching element 1 is pressed with three arranged on the outside of the frame 10 locking elements 19 in the fastener of the mounting plate 11. In this case, the final installation stop via a dimensionally stable contour on the frame 10 and the mounting plate 11, so that the altitude of the switching element 1 is defined defined in the installed state. The height tolerance compensation takes place via a slope on the latching hooks 20 of the mounting plate 11. The constructive arrangement of the resilient latching hooks 20 in the mounting plate 11 results in a compact design of the switching element 1, otherwise space would have to be provided on the switching element 1 for the deflection of the resilient latching hooks , The latching connection is advantageously designed from plastic to an electromagnetic compatibility to adjacent components guarantee. Thus, the structural design, for example, suitable for use in the tank lid of an electric vehicle in the outdoor area. When using different switching element variants, a mechanical coding between the frame 10 and the mounting plate 11 can be provided to avoid a false appearance in the mounting plate 11. In order to ensure the disassembly of the switching element 1 from the mounting plate 11, a contour is formed on the latching hook 20, on which the latching hooks 20 can be bent and thus the switching element 1 can be dismantled from the mounting plate 11. Another advantage of this structural design is that the mounting and actuation direction of the switching element 1 are the same, whereby the switching element 1 is pressed during actuation always in the end position and a release from the assembled state is not possible.

The FIG. 5 shows a perspective view of the cap 2, which is made in the multi-component injection molding process to seal the switching element 1 against the ambient conditions, a resistance to freezing, a translational movement of the switching element 1 and a search 21 and functional lighting 22 to realize. The symbol of the search illumination 21 can be embodied in various variants via an interchangeable insert in the injection molding tool and is preferably made in a white, translucent material. The functional lighting 22 is made in a transparent and volume-scattering material, the actuating surface 23 in a black opaque material and the protective membrane 12 in a black flexible plastic material. Alternative materials and colors are possible. For example, the protective membrane 12 may be made in a different color than the actuating surface 23 to indicate the operating area to the operator. In a transparent embodiment of the protective membrane 12, this could also be transilluminated, for example, to indicate the state of charge of an electric vehicle.

All components are connected to each other via melting in the injection molding process as well as mechanical detents fixed and positive and media-tight together. The cap 2 is mounted on integrally formed locking elements with the guide 4. The protective membrane 12 is mounted circumferentially with a bias over the edge 24 of the housing 9, so that the protective membrane 12 rests positively on the housing 9. In conjunction with the frame 10, which is mounted from the connector side via the housing 9, the switching element 1 is sealed. The seal is constructively designed so that in the frame 10 circumferentially a sealing contour 25 is formed, which presses into the elastic protective membrane 12 and clamped relative to the housing 9 circumferentially with constant pressure. This sealing contour 25 ( FIG. 6 ) Following a circumferentially elevated and outer edge 26 is formed, which is positioned during assembly of the frame 10, the protective membrane 12 and the sealing contour 25 in interaction, so that a secure installation is ensured. Furthermore, a control option for the assembly process is thus given. The frame 10 is clamped between the housing 9 and the protective membrane 12 and thus sits without play in the end position. The protective membrane 12 is structurally shaped so that it has a laterally encircling sealing contour 27 which laterally applies during assembly in the mounting plate 11 and thus seals the switching element 1 to the mounting plate 11. Furthermore, thus necessary for mounting the switching element 1 gap is reduced to Einbaublende 11 and it results in a homogeneous overall picture between the switching element 1 and mounting plate 11. This ensures only with a seal the switching element 1 itself and a seal to the mounting plate 11.

The robustness against freezing of the switching element 1 is realized in that constructively the protective membrane 12 of the cap 2 circumferentially evenly, starting from the height position of the mounting plate 11 toward the starting position of the switching element 1, is formed increasing. The height of the slope forms at least the actuation path of the switching element 1 from.

In the case of icing of the switching element 1, the icing is broken by the operation of the cap 2 and the translational movement of the cap 2 is released for transfer into the electrical switching signal. Due to the broken icing on actuation of the switching element 1 and the provision is possible. Due to the increased actuating surface of the switching element 1, compared to the altitude of the mounting plate, an operation with gloves is also possible.

The receiving area of the pressure compensation element 7, the printed circuit board 6, the silicone mat 5, the guide 4 and the end stop 3 are completely inside the housing 9 and the cap 2, to ensure protection of the switching system from contamination and / or fluids.

The silicone mat 5 serves to return the switching element 1 and Lichtabschottung between the search 21 and functional lighting 22. The provision is made with at least two reset domes 28 ( FIG. 3 ) with linear force-displacement curve in the force balance to the button. Alternatively, the reset domes 28 can also be used as additional switching elements to ensure, for example, a redundancy to the button. Another possible embodiment is to replace the probe with a silicone switching mat, which in turn can be performed in a variety of force-displacement characteristics, such as two or three-stage force-displacement curve. The light shielding is carried out by the use of an opaque material with a constructive meander structure between search 21 and functional lighting 22. The end stop 3 braced between two recesses in the housing 9, which are within the sealing region of the switching element 1, and the elastic silicone mat 5, which in turn presses on the circuit board 6. As a result, a play and rattle-free design of the switching element 1 is achieved in the mounted state even under vibration. The end stops are structurally arranged so that they are located exactly over the Rückstelldomen the silicone mat 28 and the button. The end stops hold that Switching element 1 in a stable rest position without stressing the protective membrane 12 with a compressive stress. The protective membrane is thus in a stress-free state, which has a positive effect on the haptic and optical properties and the service life.

LIST OF REFERENCE NUMBERS

1

switching element

2

cap

3

end stop

4

guide

5

silicone mat

6

circuit board

7

Pressure compensation element

8th

contacts

9

casing

10

frame

11

Einbaublende

12

protective membrane

13

vent channel

14

female connector

15

Guide grooves housing

16

Leadership Contours Leadership

17

End stop housing in actuating direction

18

End stop guide in actuating direction

19

Locking elements on the frame

20

Latch hook on mounting plate

21

search lighting

22

Task lighting

23

actuating surface

24

housing edge

25

Sealing contour frame

26

Edge frame

27

Sealing contour to the mounting plate

28

Reset dome silicone mat

Claims (8)

1. Illuminated, waterproof and dustproof operating element, for converting a linear movement of a button to an electrical switching signal, with an enclosure and a cap capable of being shifted axially by a stroke path between end bearings, provided with a protection diaphragm for external sealing, with a minimum of four contacts (8) and a minimum of two contacts (8) of them having the same contour in the interior of the enclosure (9) and following a deflection of their linear arrangement in the plugging area to a quadratic arrangement in the interior, a pressure compensation element (7), a printed circuit board (6) having a button and a minimum of two luminaires arranged on the middle of it, a silicone mat (5) as a reset element and a light barrier, a guide (4), a limit stop (3), a cap (2) with an moulded-on protective diaphragm (12) and a frame (10),
   characterized in that
   the cap (2) is made of a flexible plastic material by a sandwich moulding process and the interior of the operating element (1) is connected to the environment of the operating element (1) by a pressure compensation element (7) via a wave-formed ventilation duct (13) which is covered by a frame (10) forming an external protective cover for the ventilation duct (13).
2. Operating element as claimed in claim 1, characterized in that the enclosure (9) is formed as one part with an integrated plug frame (14).
3. Operating element as claimed in claims 1 and 2, characterized in that
   the interior of the enclosure (9) has a minimum of three guiding grooves (15) arranged in it, corresponding to the guiding contours (16) and the guide (4).
4. Operating element as claimed in claim 3, characterized in that the guiding contours (16) in the interior of the enclosure (9) immerse alongside the plug frame (14).
5. Operating element as claimed in claim 1, characterized in that the reception area of the pressure compensation element (7) and the printed circuit board (6) are close to the upper opening of the enclosure (9).
6. Operating element as claimed in claim 1 and at least in one of the claims 2 to 5, characterized in that
   the guide (4) has a minimum of three limit stops (18) which are arranged in the form of a T-section above the guiding contours (16).
7. Operating element as claimed in claim 1 and at least in one of the claims 2 to 6, characterized in that
   the snap-in hook (20) of the built-in shutter (11) has a contour moulded on it where the the snap-in hooks (20) can be bent open to allow a simple disassembly of the operating element (1).
8. Operating element as claimed in claim 1 and at least in one of the claims 2 to 7, characterized in that
   the frame (10) and the built-in shutter (11) have a built-in limit stop formed by a dimensionally stable contour.

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