FR2977334A1 - Electromagnetic actuator for tactile haptic feedback interface module for touch screen of e.g. audio system, in car, has biasing leaf spring placed transversely to movement of movable core and extending laterally of movable core - Google Patents

Abstract

The actuator (9) has a movable core (13) cooperating with a frame (11), where the core is driven for movement between extreme positions for generating haptic feedback. A coil (15) and a magnet (17) drive the movable core, where a biasing leaf spring (19) is placed transversely to the movement of the movable core and extending laterally of the movable core. The leaf spring defines a floating rest position for the movable core, where the leaf spring is arranged on either side of a planar base (27) of the movable core. An independent claim is also included for a tactile haptic feedback interface module.

Description

The present invention relates to a tactile interface module for a motor vehicle, in particular for transmitting a haptic feedback to a user, such as a vibratory feedback.

In the automotive field, multifunction control modules, made for example in the form of a joystick or a rotary knob, are increasingly used to control electrical or electronic systems, such as an air conditioning system, an audio system or a navigation system. Such modules may be associated with a display screen and allow navigation in drop-down menus comprising various commands relating to the systems to be controlled. However, the presence of more and more numerous and complex functions leads to a multiplication of these modules. Also, to increase the number of integrated functions and ergonomics of the man-machine interfaces, the use of a touchscreen interface module, at a control surface or a touch screen, is considered an interesting development. When a user exerts pressure on the touch screen of such a sensor, it is possible to measure the applied pressure and / or to determine the location of the place where the pressure is exerted. In this case, user support is for example associated with the selection of a command. In addition, to indicate to the user that his order has been taken into account, whether in normal driving or stopping situation but also in a degraded situation (blind manipulation, significant cognitive load), it is important that the user has a haptic feedback so as to remain focused on the road by reducing the cognitive effort associated with verifying the achievement of its action on the touch screen. For this purpose, haptic feedback control modules are already known comprising actuators, such as electromagnetic actuators, connected to the interface module for transmitting a vibration movement, so that the user perceives a haptic feedback. informing him that his order has been taken into account. These electromagnetic actuators comprise a coil and one or more magnets movable in translation relative to the coil. By feeding the coil, the 5 magnets are set in motion, and this movement is transmitted to the touch screen. A second assembly, called "voice-coil", "acoustic coil" since associated with the speakers, is obtained by mounting the reverse coil moving relative to one or more relatively fixed magnets. However, when the movable cores arrive at the end of stroke, they hit bumpers or the frame of the actuator. These repeated shocks, in addition to the unwanted noise they produce, contribute to the wear of parts. They thus reduce the effectiveness of the haptic feedback and may eventually make it necessary to replace all or part of the actuator. To overcome this defect, it is known to implement damping elements, between the parts called to clash. However, because of their function as dampers, these parts absorb energy that would have been used to set in motion. This energy absorption therefore decreases the overall efficiency of the actuator. However, these damping elements remain difficult to implement, and make assembly of the interface module complicated. For this purpose, the subject of the invention is a touch-sensitive tactile interface module actuator comprising a touch-sensitive panel capable of detecting a support of a user, connected to the touch-sensitive panel, capable of generating a haptic feedback as a function of the support detected and comprising: a frame, a movable core cooperating with the frame, intended to be driven in movement between extremal positions to generate haptic feedback, and electromagnetic actuation means for driving the core in motion mobile; characterized in that the actuator further comprises at least one preloaded spring blade disposed transversely to the movement of the moving body and protruding laterally from said movable core. The actuator may further have one or more of the following features, taken alone or in combination. The at least one leaf spring defines a floating rest position of the movable core. It comprises two spring blades disposed on either side of a flat base of the movable core. The two spring blades are two parallel branches of a metal elastic holding means. The elastic holding means is a U-folded metal blade. The elastic holding means comprises a bore intended to cooperate with clipping means of the frame. The movable core comprises a metal stirrup, said metal stirrup comprising a base on one side of which two lateral branches forming a support for magnets, and a central branch around which a coil integral with the chassis slides, and in that the spring blades are arranged on either side of the base of the metal stirrup. The spring blades are convex, the vertices of the curves being in facing relation, and 20 stresses in spacing. The spring blades are concave, the tips of the curves being oriented outwards, and compressive stresses. The spring blade on the side of the base of the metal stirrup from which the leaf spring leaves has a split portion surrounding the central leg. It comprises overmoldings on the movable core forming a guide by cooperation with corresponding shapes of the frame.

The invention also relates to a tactile feedback interface module haptic comprising a touch screen capable of detecting a support of a user, and at least one actuator connected to the touch screen, capable of generating a haptic feedback based of the support 2977334 -4- detected and comprising: - a frame, - a movable core cooperating with the frame, intended to be driven in movement between extreme positions to generate the haptic feedback, and 5 - electromagnetic actuation means to drive the moving core in motion; characterized in that the actuator further comprises at least one prestressed spring plate disposed transversely to the movement of the movable core and protruding laterally from said movable core. Said interface module may further comprise a plurality of actuators and a common controller for actuating them in predetermined patterns. Other advantages and characteristics will appear on reading the description of the following figures, given by way of non-limiting example. Figure 1 is a schematic sectional view of an embodiment of a tactile interface module according to the invention, Figure 2 is a side view of an actuator according to the invention mounted in a tactical interface module. Figure 3 is a schematic view of an elastic means according to the invention, Figure 4 is a schematic sectional view of an alternative embodiment of an interface module according to the invention. In all figures the same references apply to the same elements. FIG. 1 is schematically shown in section a touch-sensitive tactile feedback interface module 1, for example for a control panel of a motor vehicle, or for a central console of a motor vehicle, for controlling electrical systems or vehicle electronics, and can transmit a haptic feedback to a user having for example modified or selected a command so as to ensure the user takes into account the modified or selected command. The interface module comprises a touch screen 3, for example using a capacitive technology, or pressure sensitive resistors (Force Sensing Resistor, FSR), for detecting the location of a user's finger on a position on its surface. corresponding to an order. It is also possible to use a touch screen, transparent and superimposed on a display screen, functioning for example by detection of surface waves. In FIG. 1, the touch-sensitive panel is connected in a floating manner to the frame 5 of the touch-sensitive interface module 1. The connection between the surface 3 and the frame 5 is made by a connection 7 of the semi-rigid membrane type, or any another fixing means allowing limited movements, in particular in vibration along the axis A -A perpendicular to the touch-sensitive panel 3. The touch-sensitive panel 3 is connected to an actuator 9 which causes the haptic feedback during the detection of the support of the user. This actuator 9 comprises firstly a frame 11, secured to the touch screen 3, and a movable core 13 cooperating with the frame 11. The movable core 13, housed in the frame 11 is moved between extreme positions by electromagnetic actuation means 15, 17. During this reciprocating movement, the movable core 13 alternates acceleration and deceleration phases, during which said mobile core 13 causes the slab to move. touch 3, and so the haptic feedback. In addition, the actuator 9 comprises prestressed spring blades 19. The movable core 13 is caught between these prestressed spring blades 19. These leaf springs are arranged transversely with respect to the movement 20 of the movable core 13 and protrude laterally from said movable core 13, so as to allow their attachment to the frame 11. The spring blades 19 assist the electromagnetic actuating means, here a coil 15, and magnets 17 in that they store a part of the kinetic energy 30 communicated to the mobile core 13 during its deceleration phases in the form of elastic potential energy, and then to restore it during the acceleration phases . The prestressed spring blades 19 define in the absence of supply of the coil 15 a rest position of the movable core 13. The rest position is floating: the movable core 13 is not in contact with any other component of the actuator 9.

The exemplary embodiment of FIG. 1 places the spring blades 19 symmetrically about the axis A -A, which is parallel to the direction of movement of the movable core 13, represented by the arrow 20, and which passes by the center of gravity G of the mobile core 13. Thus, they generate no torque on the movable core 13. This has the effect of preventing the rotation of said mobile core 13, which may imply that it gets stuck or else that it hits other mechanical parts.

To achieve the electromagnetic actuating means 15, 17, the frame 11 carries a coil 15 which can provide a magnetic field and the movable core 13 carries at least one magnet 17, preferably several, arranged closest to the coil 15 and free in translation along the axis AA. Figure 1 shows an embodiment of a so-called "suspended" actuator. Suspended means that the actuator 9 is not connected to the frame 5 of the touch interface module 1, and the frame 11 is secured to the touch screen 3.

In the suspended assembly is the mobile core 13 which sets in motion the touch screen 3 to generate the haptic feedback. The frame 11 is support for fixing to the touch screen 3. The frame 11 forms a receptacle accommodating the rest of the actuator 9. The actuator 9 then forms a well-defined functional block, easily mountable and removable interface module 1. Indeed, this functional block is simply screwed or clipped to the touch screen 3, and can be interchanged quickly.

The movable core 13 comprises two magnets 17, which are held opposite the sides of the coil 15, and a stirrup 21, to which the magnets 17 are fixed by clipping or gluing. The stirrup 21 has a cross-section E, the central branch 23 is embedded in the coil 15. The two lateral branches 25 carry the magnets 17. The branches 23, 25 are carried by a relatively flat base 27 , that the spring blades 19, arranged on both sides, enclose.

FIG. 2 shows a second embodiment of a touch interface module 1. The frame 11 is composed of two parts: a coil 15 and a fixed support 29. The fixed support 29 forms a frame and surrounds the It also accommodates the other parts of the actuator 9. The spool 15, in engagement with the movable core 13, is in particular introduced laterally into the frame formed by the fixed support 29, and is held there by tongues 31. disposed on the side of the coil 15 which cooperate with latching sites 33. In this figure it can be seen that the leaf spring 19 may be two parallel branches of a metal elastic holding means 35, inserted by lateral openings 15 37 An embodiment not shown shows that the movable core 13 includes overmoldings forming a guide by cooperation with corresponding shapes of the frame 11.

The metal elastic holding means 35 is shown in more detail in FIG. 3. It can be seen in this figure that the elastic holding means is composed of a metal blade, folded into a flat bottom U, the two parallel branches starting. In particular, one of the branches comprises at its center a longitudinal slot 41, in which the central branch 23 comes into being during assembly. It can be seen in Figure 3 that the spring blades 19 have a curved shape. The spring blades 19 are convex, the vertices of the curves facing each other, which makes it possible, by pinching the flat base 27, to apply a spaced stress on the leaf spring 19 and thus to define the rest position of the spring Mobile core 13. An alternative embodiment provides that the leaf spring 19 is concavely reciprocated, the apices of the curves outward. In this case the rest position of the movable core 13 is defined by a compressive stress of the spring blades 19. The flat bottom 39 of the metal elastic holding means 35 further comprises 5 fixing means on the fixed support 29. These means for fixing here are in the form of a bore 43 intended to cooperate with a clipping finger of corresponding shape located on the fixed support 29 of the frame 1.1 between the lateral openings 37. Alternatively, the fixing means may comprise a screw inserted in piercing 43, or a riveting, or a hot bouterollage. FIG. 4 shows an example of an alternative embodiment of an interface module 1, in which the spring blades 19 enclose the ends of the mobile core 13, in particular the central branch 23 of the stirrup 21.

An interface module 1 may further include a plurality of actuators and a common controller for actuating them in predetermined patterns.

The invention makes it possible to obtain an actuator with simplified assembly. Indeed the spring blades 19 can be inserted laterally into the frame 11, and the prestressing is done automatically while helical springs must be in place and constrained during the entire assembly operation.

Claims (15)

REVENDICATIONS1. Interface module actuator (1) with haptic feedback, for a touch panel (3) able to detect a support of a user, connected to the touch screen (3), capable of generating a haptic feedback depending on the support detected and comprising: - a frame (11), - a movable core (13) cooperating with the frame (11), intended to be driven in movement between extremal positions to generate the haptic feedback, and - means of electromagnetic actuation (15, 17) for driving the movable core (13) in motion; characterized in that the actuator further comprises at least one prestressed leaf spring (19) arranged transversely to the movement of the movable core (13) and laterally projecting from said movable core (13). 15 2. An actuator according to claim 1, characterized in that the at least one leaf spring (19) defines a floating rest position of the movable core (13). 3. Actuator according to one of the preceding claims, characterized in that it comprises two spring blades (19) disposed on either side of a planar base (27) of the movable core (13). 4. An actuator according to claim 3, characterized in that the two leaf spring (19) are two parallel branches of a metal elastic holding means (35). 25 5. Actuator according to claim 4, characterized in that the elastic holding means (35) is a metal blade folded U. 6. Actuator according to at least one of claims 4 or 5, characterized in that the elastic holding means (35) comprises fixing means (43) to the frame (11). 30-10- 7. An actuator according to claim 3, characterized in that the fastening means (43) to the frame (11) comprise a bore (43) for cooperating with clipping means of the frame (11). 8. An actuator according to claim 3, characterized in that the fastening means (43) to the frame (11) comprise a bore (43) intended to cooperate with a screw or a riveting or hot riveting. 9. Actuator according to one of claims 3 to 8, characterized in that the movable core (13) comprises a metal stirrup (21), said metal stirrup (21) having a flat base (27) on one side of which two lateral branches (25) forming support for magnets (17), and a central branch (25) around which a coil (15) integral with the frame (11), and that the spring blades (19) are arranged on either side of the flat base (27) of the metal stirrup. 10. Actuator according to claim 9, characterized in that the spring blades (19) are convex, the peaks of the curves being vis-à-vis, and spaced constraints. 11. An actuator according to claim 9, characterized in that the spring blades (19) 20 are concave, the apices of the curves being oriented outwardly, and compressive stresses. 12. Actuator according to claim 9, characterized in that the leaf spring (19) on the side of the flat base (27) of the metal stirrup from which the legs (23, 25) 25 has a slot (41) in which is housed the central branch (25). 13. Actuator according to one of the preceding claims characterized in that it comprises overmoldings on the movable core (13) forming a guide by cooperation with corresponding shapes of the frame (11). 2977334 -11- 14. Interface module (1) touch tactile haptic comprising a touch screen (3) adapted to detect a support of a user, and at least one actuator connected to the touch panel (3), able to generate a haptic feedback according to the detected support and comprising: - a frame (11), 5 - a movable core (13) cooperating with the frame (11), intended to be driven in movement between extremal positions to generate the haptic feedback, and - electromagnetic actuating means (15, 17) for driving in motion the movable core (13); Characterized in that the actuator further comprises at least one prestressed leaf spring (19) arranged transversely to the movement of the movable core (13) and laterally projecting from said movable core (13). 15. Interface module (1) according to claim 12, characterized in that it comprises a plurality of actuators and a common controller for their actuation according to predetermined patterns.