EP2872960A1

EP2872960A1 - Push button for motor vehicle key module

Info

Publication number: EP2872960A1
Application number: EP13735339.7A
Authority: EP
Inventors: Benoît DELANDE; Karim NAMAR
Original assignee: Valeo Securite Habitacle SAS
Current assignee: Valeo Comfort and Driving Assistance SAS
Priority date: 2012-07-13
Filing date: 2013-07-12
Publication date: 2015-05-20
Also published as: FR2993377A1; US9870882B2; FR2993377B1; WO2014009546A1; US20150179370A1; JP2015522206A; CN104781746A

Abstract

The invention relates to a button of the push-button type, comprising: a fixed part (3) forming a chassis, a mobile part (5) capable of translational movement between a rest position, adopted in the absence of actuation by a user, and an actuating position, adopted when the mobile part (5) is depressed with respect to the fixed part (3), a switch (7) toggling from a first state to a second when the mobile part (3) is brought into the actuating position, a flexible membrane (9) positioned between the mobile part (5) and the switch (7), connected by its edges to the fixed part (3) and returning the mobile part (5) to the rest position in the absence of actuation by the user, characterized in that: the membrane (9) has a thinning (15) of its thickness facing the switch (7). The invention also relates to the vehicle key module comprising at least one such button (1).

Description

Push button for motor vehicle key module

The present invention relates to a push button, of the type pressed by a user to actuate a switch, in particular integrated in a key module of a motor vehicle, comprising a communication member for the remote opening and closing of the opening of the vehicle.

These push buttons rest on the depression of a moving part which is set in motion by a pressure force on the part of a user, and sinks relative to a fixed part, usually the body carrying the button. The buttons, in particular pusher, present a curve of the force applied as a function of the generally increasing depression, up to a threshold value, where the force applied decreases abruptly. This reduction of effort is felt by the user, it is that which is perceived as a <click> even if the mechanism produces no sound, which provides a haptic feedback ensuring the user that his command is taken into account.

The decrease in perceived effort is called the blistering effect of the button, which is measured as the F / F ratio between the decrease in effort and the absolute value of the maximum effort applied just prior to the said decrease, which is therefore adimensionné. This blistering effect results from the mechanism of the switches used which have several states of minimum energy, corresponding to different switching states, separated two by two by a potential energy barrier which is overcome by the actuating gesture. From an initial state, the maximum potential energy is reached at the so-called tipping point, beyond which the mechanism switches all alone in the final state.

It is known to use flexible membranes as elastic element ensuring the return of the moving part of the push button. These membranes provide a dual role in that they allow the return to a rest position of the movable part, and in that they isolate the electronic switch from the outside environment.

For better actuation of the switch, the portion of the diaphragm often has an extra thickness on the surface facing the switch acting as a finger pushing the switch. These structures give a blistering effect of the order of 15 to 20%.

This feeling of haptic feedback can be considered insufficient, in that, in general, a clearly marked blistering effect is felt as a sign of quality by a user.

In order to at least partially meet the previously mentioned need, the subject of the invention is a pusher type button, comprising: a fixed frame part, a mobile part, movable in translation between a rest position, adopted in the absence of actuation by a user, and an actuating position, adopted by depressing the moving part relative to the fixed part,

a switch, swinging from a first state to a second when the moving part is brought into the actuating position,

a flexible membrane disposed between the moving part and the switch, connected by its edges to the fixed part and bringing the moving part back to the rest position in the absence of actuation by the user, characterized in that: the membrane comprises a thinning of its thickness vis-à-vis the switch .

The buttons thus obtained have improved characteristics in terms of haptic feel of the blistering effect, making said buttons more pleasant and potentially more practical and safe to use.

The button according to the invention may furthermore have one or more of the following characteristics, taken alone or in combination.

Thinning has a recess on the outer surface of the membrane, and the movable portion has a complementary shaped protrusion inserted into the recess.

Thinning has a recess on the inner surface of the membrane, and the switch has a complementary shaped upper portion which fits into the recess when actuating the button.

The recess can then in particular be of gradually varying section, for example, it can be conical, trapezoidal, or staircase.

The moving part is glued or welded to the outer surface of the membrane.

If necessary, the recess and the protrusion may be slightly different in shape so as to cause an accumulation of glue between the two.

The outer surface of the membrane has grooves for the glue intended to keep the mobile part glued.

The membrane is made of an injected thermoplastic elastomer, the thermoplastic injected elastomer may be one of the following: elastomeric polyurethane, elastomeric polyethylene, elastomeric polyamide.

The invention also relates to the vehicle key module transmitter integrated for the remote control of locking / unlocking functions of the opening of a vehicle, characterized in that it comprises at least one button as previously described.

Other features and advantages of the invention will appear more clearly on reading the following description, given by way of illustrative and nonlimiting example, and the appended drawings in which: FIG. 1 shows a pusher type button according to a first embodiment of the invention, in schematic sectional view, Figure 2 is a top view of a membrane as used in the button of Figure 1, Figure 3 shows a pusher type button according to a Second embodiment of the invention, in a schematic sectional view, Figure 4 is a simplified graph of the reaction force as a function of the depression during the actuation of a button according to the invention.

In all the figures, the same references refer to the same elements.

In Figure 1 is schematically shown a push button 1 according to one embodiment of the invention. The button 1 comprises a fixed part 3, forming a frame, a moving part 5, intended to be depressed to actuate the button, a switch 7, switching between two states, a first and a second, for example open and closed, when the button 1 is actuated and a membrane 9, attached to the fixed part 3 and carrying the movable part 5 of the button 1.

The fixed part 3 of the button 1 is for example the body of an integrated transponder vehicle key module for the remote control of vehicle locking functions, such as the locking / unlocking of the doors and the tailgate trunk.

Such a key module generally comprises a plurality of buttons 1, one for locking the doors, one for unlocking them, and possibly an additional button for locking / unlocking the tailgate separately.

The movable portion 5 is a plate, metal or plastic, preferably molded plastic, having an outer face generally bearing a pictogram indicating the function of the button. The moving part 5 is generally integrated in the front face of the key module, and is the one on which the user presses to actuate the button 1.

The moving part 5 is movable in translation between a rest position, taken in the absence of pressure or actuation, and an actuating position, corresponding to the position taken by said movable part 5 when the user pushes it in. to activate the button 1.

Under the moving part 5 is located an electronic switch 7. This switch 7 is a toggle switch. The switch 7 is crushed when the user pushes the movable portion 5 to a tilting point reached when the movable portion 5 is in the actuating position. When the point of switchover is reached, the switch 7 switches from a first initial switching state, for example open or closed if it is a switch, to a second final switching state, closed or open respectively in the case of 'light switch.

These switches 7 generally comprise a mobile part retracting in a fixed part during their actuation, and an elastic return element bringing the moving part back to the rest position and storing the potential energy required for the switchover (switches known as <microswitch> or integrated switches).

The switch 7 is generally carried by a printed circuit board, also carrying electronic elements intended to be controlled by the actuation of the switch 7. In the case of a key module of a motor vehicle, the printed circuit board door for example the emitter of the locking / unlocking opening signals.

Between the mobile part 5 and the switch 7 is placed a membrane 9. This membrane 9 is a flexible membrane, in particular made by injection of thermoplastic elastomer, for example thermoplastic elastomer polyurethane (TPU), thermoplastic polyethylene elastomer (TPE) or thermoplastic polyamide elastomer (TPA).

The membrane 9 is attached by its edges to the fixed part 3, for example by gluing. It has an upper surface 11 which carries the movable part 5, and zones of deformations 13, between the parts bonded to the fixed part 3 and the upper surface 11.

Due to its elasticity, the membrane 9 forms an elastic return element, which brings the mobile part 5 to the rest position when the user releases the pressure on said moving part 5. To allow easier depression of the movable portion 5, and to prevent permanent non-elastic deformation of the membrane 9, it comprises deformation zones 13 on its periphery, comprising a peripheral portion of membrane 9 with a U-shaped section. The deformation of the membrane 9 is then by displacement of the fold forming the bottom of the U along a peripheral portion of the membrane 9 and / or by curvature of the panels corresponding to the bars of said U.

The diaphragm 9 has a thinness of its thickness, opposite the switch 7. In the embodiment shown in FIG. 1, the thinning 15 essentially comprises a recess, of conical shape, situated on the outer surface 11 of the membrane 9.

Other embodiments can be envisaged, for example with thinning 15 of rounded, trapezoidal or even staircase shape. These gradually varying section shapes make it possible to ensure that during injection molding, the injected material fills the entire mold space, including the thinned portion, despite surface tensions and viscosity effects.

If the materials allow it, the thinning 15 can of course simply be parallelepipedic. The moving part 5 comprises a protuberance 17 of corresponding shape and dimensions, inserted in the recess forming the thinning 15, of the glue 19 being applied in said recess forming the thinning 15 before bringing the movable part 5 into contact for its fixation. A slight difference in shape, for example of angle of opening of the cone, can be provided between the recess 15 and the protuberance 17 so as to cause a controlled accumulation of glue 19 therebetween, which improves fixation and rigidity.

To allow better bonding of the movable portion 5, the outer surface of the membrane 9 has a plurality of grooves 21, in which the glue 19 for holding the movable part 5 infiltrates and takes.

Alternatively, the moving part 5 can be welded, for example by ultrasound or laser on the outer surface of the membrane.

Figure 2 is a top view of the membrane 9 as previously described. It is possible to see in this figure the pattern of the grooves 21, here in the form of parallel lines. Other patterns are also conceivable, such as braces, concentric circles, even even single point indentations evenly distributed.

In FIG. 2 it can also be seen that the deformation zone 13 makes the complete turn of the membrane 9. Thus surrounding the membrane 9 with a deformation zone 13 in its entirety and by gluing it to the fixed part 3 on the whole from the periphery, there is a relative tightness of the space inside the membrane 9 and the fixed part 3, which makes it possible to protect the switch 7 from any harmful external elements infiltrating into the button 1, for example dust and moisture. The thinning 15 allows a better transmission of the forces of the switch 7 to the mobile part on which rests the finger of the user who is intended to feel the blistering effect.

In particular, the fact that the membrane 9 is flexible means that it absorbs part of the forces in the form of deformations and shears, which are not felt by the user. From then on, its thinning decreases the portion of efforts dissipated.

By covering almost the entire surface of the membrane 9 of grooves 21, a greater adhesion of said membrane 9 to the moving part is obtained, which improves the stiffness of the button 1 and thus the haptic feeling by preventing a dispersion of oscillating forces of the membrane 9 not transmitted to the moving part 5.

Figure 3 shows an alternative embodiment of button 1 of the push type according to the invention. In this embodiment, the thinning of the membrane 9 is in the form of a recess on its inner surface, facing the switch 7. The switch 7 then has an upper portion 23 of corresponding shape and dimensions which engages in the recess when the moving part 5 is brought into actuation position. The upper surface 11 of the membrane 9 is then flat, with the exception of the grooves 21 for the glue 19. The surface of the movable portion 5 located opposite is also flat, and in particular does not comprise any protuberance 17.

FIG. 4 is an approximate graph of the force F of reaction of the push button 1 as a function of the depression e applied to the moving part 5. The force F is given in Newton N, and the depression e in millimeters mm.

The evolution of the force F as a function of the depression e is divided into four segments, numbered i to iv.

In first part i, of a depression e zero at a value of depression e where the membrane 9 comes into contact with the switch 7, the force F evolves so linear, according to a first slope.

During this part i, the reaction essentially comes from the membrane 9, which is elastically deformed, and tends to return to the rest position with a force F proportional to the deformation which is here the depression e. The first slope thus corresponds to the stiffness constant of the membrane 9.

In the second part H, the force F increases more importantly, with a slope possibly variable increasing and more important than in the first part i.

During this part H, the reaction F comes from the membrane 9 and the switch 7, which comprises an elastic element storing the energy of deformation until reaching the tilting point, for example a metal spring blade, or a blistering element bearing contacts.

In the third part iii, the force F decreases abruptly from a value Fl, local maximum, to a value F2, local minimum. During this period iii, the tipping point is reached initially, the switch switches from a first state to a second, the elastic element yielding the energy required for said tilting, which causes the observed reaction force drop F.

In the fourth part iv, the force F increases again strongly with the depression e.

During this period iv, the switch 7 has reached the limit of its elastic deformability, and all the button is in fact being compressed until permanent deformation of its components. This fourth part is not covered during normal use, and corresponds to the bottom stop of the button 1.

The blistering effect of the buttons 1 according to the invention, given as being (Fl ^~ F2) / F1, is, according to prototype studies, greater than 40%, of the order of 43% on average.

The haptic feedback felt is thus much greater, which improves the appreciation of the button 1 by the user and makes the use of said button 1 easier and safer, since an actuation not felt and therefore a double operation because that the first is not felt is less likely, especially for example when the user wears gloves lessening the haptic feeling.

Claims

Push button, comprising:

- A fixed part (3) forming a frame, a movable part (5), movable in translation between a rest position, adopted in the absence of actuation by a user, and an actuating position, adopted by depressing the moving part (5) with respect to the fixed part (3),

a switch (7), swinging from a first state to a second state when the mobile part (3) is brought into the actuating position,

- A flexible membrane (9) arranged between the movable part (5) and the switch (7), connected at its edges to the fixed part (3) and bringing the mobile part (5) to the rest position in the absence actuator by the user, characterized in that: the membrane (9) comprises a thinning (15) of its thickness vis-à-vis the switch (7).

Button according to claim 1, characterized in that the thinning comprises a recess on the outer surface (11) of the membrane (9), and in that the movable part (5) has a protuberance (17) of complementary shape inserted in the recess (15).

Button according to claim 1, characterized in that the thinning has a recess on the inner surface of the diaphragm (9), and in that the switch (5) has an upper portion (23) of complementary shape which fits into the recess (15) when actuating the button (1).

4. Button according to one of claims 2 or 3, characterized in that the recess (15) is gradually varying section.

5. Button according to claim 4, characterized in that the recess (15) is conical.

6. Button according to claim 4, characterized in that the recess (15) is trapezoidal.

7. Button according to claim 4, characterized in that the recess (15) is in staircase.

Button according to one of the preceding claims, characterized in that the movable part (5) is glued to the outer surface (11) of the membrane (9).

9. Button according to claims 2 and 8, characterized in that the recess (15) and the protuberance (17) are slightly different shape so as to cause an accumulation of glue (19) between the two.

10. Button according to one of claims 8 or 9, characterized in that the outer surface (11) of the membrane (9) has grooves for the glue (19) for holding the movable part (5) glued.

11. Button according to one of claims 1 to 7, characterized in that the movable part (5) is welded to the outer surface (11) of the membrane (9).

Button according to one of the preceding claims, characterized in that the membrane (9) is made of an injected thermoplastic elastomer.

13. Button according to claim 12, characterized in that the injected thermoplastic elastomer is one of the following: elastomeric polyurethane, elastomeric polyethylene, elastomeric polyamide.

14. Vehicle key module with integrated transmitter for the remote control of locking / unlocking functions of the opening of a vehicle, characterized in that it comprises at least one push button (1) comprising:

- A flexible membrane (9) arranged between the movable part (5) and the switch (7), connected at its edges to the fixed part (3) and bringing the mobile part (5) to the rest position in the absence actuation by the user, wherein the membrane (9) has a thinning of its thickness vis-à-vis the switch (7).