Horn switch for a vehicle steering wheel

Abstract

The invention relates to a vehicle steering wheel comprising: - a safety module, - a module cover (4) that is movable with respect to the steering wheel body in order to activate a horn, and - at least one horn switch (40) comprising: • a push member (401) secured to the module cover (4); • a movable contact (4010) mounted on the push member (401); • a static contact (402) secured to the steering wheel body, the horn switch being of the normally closed type; and • a resilient element (404) arranged to return the module cover (4) to the rest position, characterised in that the resilient element (404) is arranged to position the module cover (4) with respect to the steering wheel body in at least one direction transverse to a direction (z) of movement of the module cover (4).

Description

DESCRIPTION TITLE: Vehicle Steering Wheel Horn Switch Technical field of the invention

[0001] The present invention relates generally to horn switches, and more particularly to horns arranged in vehicle steering wheels and used to open or close an electrical circuit for controlling the horn. State of the art

[0002] It is known in the prior art of horn switches, as in document US20020175505 or document US7547042. However, these systems comprise numerous parts and can be complex. Therefore, these systems may represent an additional cost, and / or significant assembly time, and / or additional assembly complexity. Description of the invention

[0003] One object of the present invention is to address the drawbacks of the prior art mentioned above and, in particular, firstly, to provide a vehicle steering wheel incorporating a switch that simplifies the connections and improves the precision between the safety module, the safety module cover, and the steering wheel frame. Another object of the invention may be to provide a vehicle steering wheel incorporating a switch that reduces costs, and / or assembly time, and / or assembly complexity, while ensuring an attractive appearance and high perceived quality.

[0004] To this end, a first aspect of the invention may relate to a vehicle steering wheel comprising: - a steering wheel body, - a security module, - a module cover, movable between a rest position and an activated position relative to the steering wheel body, and / or relative to the safety module, to activate an audible warning, and arranged to at least partially cover the safety module, - at least one horn switch including: • a push button attached to the module cover, • a moving contact embedded on the push button, • a static contact fixed to the steering wheel body, the horn switch being of the normally closed type in the rest position with the moving contact in electrical contact with the static contact, • An elastic element arranged to return the module cover to the rest position, characterized in that the elastic element can be arranged to locate, i.e., to block at least one degree of freedom, the module cover relative to the steering wheel body in at least one direction transverse to a direction of movement of the module cover. The module cover can also be a component of the module, i.e., the safety module with its module cover can be attached to the steering wheel in a single operation. The steering wheel body can be a steering wheel frame.According to the implementation described above, designing the elastic element to block one degree of freedom in at least one direction transverse to the direction of movement of the cover can limit the number of parts required for precise positioning of the module cover relative to the steering wheel body while ensuring the correct travel required to activate the horn. In particular, once mounted on the steering wheel, the safety module cover is movable and not in direct contact with the steering wheel body (in other words, it can be moved relative to the steering wheel body): the position of the safety module cover is simply defined by the elastic element of the horn switch. The components of the tolerance chain are as follows. The reduced number of components allows for very precise adjustment of the module cover relative to the steering wheel body, along directions transverse to the cover's direction of movement. Since the user's perception of product quality can be partly determined by the clearances and regularity of these clearances between the module cover and the decorative piece, the cover's fit relative to the decorative piece is a crucial factor in the final appearance of the vehicle's steering wheel, and the above implementation improves, or at the very least guarantees, the perceived quality.

[0005] The steering wheel can be defined by the following characteristics, taken individually or in combination.

[0006] According to one embodiment, the activated position of the module cover may correspond to a pressed or deformed position of the module cover, a command made by a vehicle user wishing to activate the vehicle's horn, in which the moving and static contacts are separated, so as to cut off the passage of an electric current.

[0007] In one embodiment, the rest position of the module cover can correspond to a closed position of the switch, in which an electric current can flow. Using a normally closed buzzer switch to activate a buzzer can reduce the required movement of the cover, i.e., the push button travel, to trigger or activate the buzzer. This is because the absence of electric current can be detected as soon as the cover leaves its rest position, whereas the restoration of current can only be detected when the cover reaches the end of its travel (the activated position) in the case of a normally open switch.

[0008] In one embodiment, the module cover is movable relative to the safety module. In another embodiment, the safety module includes a gas generator and / or an airbag. safety and / or a mounting plate for one of the gas generators and the airbag, and the module cover is movable relative to the gas generator and / or the airbag and / or the mounting plate. In other words, the module cover is movable between a rest position and an activated position relative to the safety module to activate an audible alarm, and arranged to at least partially cover the safety module.

[0009] In one embodiment, the push button is directly mounted or fixed to the module cover. In another embodiment, the push button is directly actuated by the module cover. In yet another embodiment, the connection between the push button and the module cover is such that a movement of the module cover directly causes a movement of the push button (typically the same movement).

[0010] In one embodiment, the elastic element can be arranged to locate the module cover relative to the steering wheel body along two directions transverse to a direction of movement of the module cover. Typically, if the direction of movement of the module cover is the z-axis of a Cartesian coordinate system, then the elastic element can be arranged to block the cover's movement along the x and y directions.

[0011] According to one embodiment, the elastic element can be arranged to locate, i.e. block at least one degree of freedom, the module cover relative to the safety module, typically itself fixed to the steering wheel body in at least one direction transverse to a direction of movement of the module cover.

[0012] According to one embodiment, the elastic element can be arranged to locate the module cover in two directions transverse to a direction of movement of the module cover. Typically, if the direction of movement of the module cover is the z-axis of a Cartesian coordinate system, then the elastic element can be arranged to block the movement of the lid along the x and y directions.

[0013] According to one embodiment, the elastic element can be arranged between the module cover and a fixed part of the steering wheel: the steering wheel body, a decorative part of the steering wheel.

[0014] To clearly define the relationship between the module cover and the safety module, these two elements are distinct in their connection to the rest of the steering wheel: - the safety module is mounted fixed or attached to the steering wheel or steering wheel body, typically in a fixed or direct manner (although with, for example, vibration dampers inserted), - The module cover is designed to conceal or cover an opening or passage in the safety module through which the airbag can deploy, and is mounted, fixed, or attached to the steering wheel (or the safety module) in such a way as to allow relative movement between the module cover and the steering wheel (and the safety module). Naturally, the module cover remains attached to the steering wheel during deployment, and for this purpose, primary hooks may be provided to prevent the module cover from detaching; these primary hooks may be integral to the safety module.

[0015] In one embodiment, the vehicle steering wheel may include at least one decorative piece fixed, i.e., anchored or fixed (i.e., by means of a fixed connection), to the steering wheel body, and the elastic element may be arranged between the push button and a reference portion of the decorative piece. The elastic element may therefore include a portion intended to be fixed relative to the reference portion of the decorative piece so as to connect the push button and the rest of the horn switch to the steering wheel body. Thus, the positioning of the cover (and the integrated push button) is defined along the two axes perpendicular to the direction of movement of the module cover. that it depends only on the assembly between on the one hand the elastic element and the decorative piece, and on the other hand between the pusher and the elastic element.

[0016] In one embodiment, the elastic element may comprise an external surface and an internal bore. The external surface of the elastic element may be in contact with a reference portion of the decorative part, and the internal bore of the elastic element may be in contact with the pusher. In particular, the external surface may be a lateral surface or a flank of the elastic element. If the elastic element has a shape of revolution or a cylindrical shape, positioning by the decorative part and / or the pusher may be performed along a radial direction of the elastic element. In one embodiment, only the elastic element is provided to allow centering of the pusher along the transverse directions of the pusher's axis (in other words, the degrees of freedom of the cover along the transverse directions are restricted only by said at least one elastic element).To ensure minimal friction during pusher movement, an anti-friction agent can be applied to the elastic element (for example, its bore).

[0017] In one embodiment, the elastic element can also act as a stop on one of its outer faces against the pusher when the lid is being pushed down. The stop can be positioned according to the direction of the lid's insertion or movement.

[0018] In one embodiment, the reference portion of the decorative part may include three projections, and the outer surface of the elastic element may include three grooves. Each groove on the outer surface of the elastic element may be in contact, i.e., engaged, with a projection of the reference portion of the decorative part. The three projections may be arranged at approximately 120° to each other to ensure a secure fit of the elastic element relative to the reference portion of the decorative part. In one embodiment, there may be no play between the elastic element and the reference portion. of the decorative piece. A slightly tight fit can be planned (for example a negative gap of 0.1 mm, 0.2 mm, 0.5 mm).

[0019] According to one embodiment, the module cover can at least partially cover the decorative piece, so as to guarantee a small gap between the decorative piece and the module cover and / or a beautiful appearance with the decorative piece covered by the cover.

[0020] According to one embodiment, a cover gap between the module cover and the decorative piece can be less than 1 mm, preferably less than 0.5 mm.

[0021] According to one embodiment, a stroke of the pusher and / or the cover may be less than 1 mm.

[0022] In one embodiment, the switch may include a switch body arranged to fix the push button to the reference portion of the decorative part, for example by means of a clip or a hook, allowing a radial clearance (typically transverse to the direction of movement of the module cover), preferably positive and, for example, less than 0.5 mm, between the switch body and the reference portion of the decorative part. The switch body can thus float relative to the handwheel body, so that only the elastic element ensures the positioning of the push button, and therefore of the module cover, in directions transverse to the axis of movement of the module cover.

[0023] In one embodiment, the vehicle steering wheel may include a sliding connection between the switch body and the push button (only one translational degree of freedom is possible). The switch body may guide the push button along the axis of movement of the module cover.

[0024] According to one embodiment, the vehicle's steering wheel may include at least three switches, and preferably four switches, so as to extend the sensitivity of the horn to a larger surface area of ​​the module cover, i.e. to a decentering of the force applied by the user on the module cover.

[0025] In one embodiment, the push button can be fitted, i.e., tightened by a negative clearance, into a cover well, for example, during the installation of the safety module on the vehicle's steering wheel, so as to prevent relative movement between the module cover and the push button. In one embodiment, the cover well can be formed by a tubular portion extending from a lower or hidden face of the cover. In an alternative embodiment, the cover well can be arranged on the push button and configured to receive a pin arranged on the cover.

[0026] In one embodiment, the clearance between the safety module housing and the module cover may be greater than the clearance between the module cover and the decorative part. This larger clearance may allow for damping of the safety module housing and its contents relative to the steering wheel body.

[0027] In one embodiment, the elastic element can be an elastomer part, preferably silicone or ethylene propylene diene monomer (EPDM), preferably cylindrical in shape and injection-molded. The use of deformable EPDM allows the push button to return to the module cover's rest position after the user has released pressure on the cover. The use of deformable EPDM also ensures reliable and precise positioning between the cover and the decorative element through material continuity. Using an elastomer such as silicone or EPDM for the elastic element provides excellent resistance to environmental conditions, such as UV radiation, ozone, and temperature variations, thus ensuring a longer lifespan for the safety module.A cylindrical shape of the elastic element can make it easier to hold the elastic element by the reference portion of the part. decorative, and uniform force distribution and improved shock absorption. In one embodiment, the elastic element can be a single piece. In other words, the elastic element is not a metal spring; typically, it is not a coil spring. The elastic element is flexible enough to deform under compression when the horn is activated and sufficiently rigid transversely to ensure stable transverse centering of the module cover. Advantageously, the hardness of the elastic element is between 70 and 80 Shore A.

[0028] In one embodiment, the safety module can be fixed (for activation of the audible warning) to the steering wheel body. In another embodiment, the safety module can be mounted directly onto a steering wheel frame (typically a metal frame or casing). In another embodiment, the safety module can be mounted on a plate supported by the steering wheel body. In particular, and in one embodiment, the safety module can be mounted with permanent contact between at least one retaining hook of the safety module and at least one elastic retaining element such as a retaining ring. In one embodiment, the retaining ring can be attached to the steering wheel frame. In another embodiment, the retaining ring can be attached to the plate.According to this implementation, the safety module (with the exception of the movable cover) can be considered to be mounted on the steering wheel body, and in particular the safety module is fixed to the steering wheel body without play, at least in the direction of movement of the module cover.

[0029] In one embodiment, the safety module may include a play compensation device for a specific mounting direction of the safety module on the steering wheel. In another embodiment, the retaining hook may include an inclined retaining surface, and the safety module may include a plating surface arranged to be plated. on the steering wheel body, the steering wheel frame, or the mounting plate. This allows for compensation of manufacturing tolerances depending on the mounting direction of the safety module on the steering wheel.

[0030] In one embodiment, the steering wheel may include at least one damping element arranged between the safety module and the steering wheel body, for example, between the steering wheel body and the mounting plate. This allows for the damping of vibrations of the module, which is arranged to be fixed relative to the steering wheel body (in the absence of vibrations). When a damping element is added, the clearance between the module cover and the module may be greater than in the case of a steering wheel without a damping element, in order to incorporate into this clearance the damping of vibrations of the safety module relative to its module cover, the movement of which is independent of the safety module.

[0031] In one embodiment, the steering wheel may include at least one damping element arranged between the safety module and the steering wheel body when the safety module is mounted on a plate, itself fixed to a steering wheel frame. In this case, the mounting may allow at least one degree of freedom of the safety module to be blocked along the axis of movement of the module cover. In this configuration, the safety module is fixed relative to the steering wheel body for the activation of the audible warning device, and micro-dampening movements are permitted by the damping element.

[0032] According to one embodiment, when the safety module is mounted directly on the frame, the steering wheel can be free of a damping element between the safety module and the steering wheel body. In this case, the assembly is compact.

[0033] According to one embodiment, the module cover can be manufactured so as to be deformable under pressure from a vehicle driver or during mounting on the steering wheel. Thus, the cover The module can be made of olefin-based thermoplastic elastomer (TPO), or EPDM, with a thickness of less than 3 mm. This flexibility can also prevent over-staticity of the assembly between the module cover and more than three switches, and can make its adjustment more flexible by allowing the module cover to take on a different geometry once it is positioned on the handwheel by at least one elastic element. Description of the figures

[0034] Other features and advantages of the present invention will become more apparent upon reading the following detailed description of embodiment(s) of the invention given by way of non-limiting example(s) and illustrated by the accompanying drawings, in which:

[0035] [fig. 1] represents a front view of a vehicle steering wheel including a horn switch according to the invention;

[0036] [fig. 2] represents an isometric view of a vehicle steering wheel well arranged at the level of a vehicle steering wheel hub of figure 1, to receive a safety module housing, horn switches according to the invention being arranged in the well;

[0037] [fig. 3] represents an exploded view of a horn switch according to the invention and visible in figure 2;

[0038] [fig. 4] represents an isometric view of the horn switch in figure 3, without a push button and mounted on a reference portion of a decorative part;

[0039] [fig. 5] represents a cross-sectional view of the horn switch along plane AA of figure 4;

[0040] [fig. 6] represents a cross-sectional view of the vehicle's steering wheel along a plane BB of figure 1;

[0041] [fig. 7] represents a cross-sectional view of the vehicle steering wheel according to a CC plane of figure 1 without the safety module and according to an embodiment with damping;

[0042] [fig. 8] represents a cross-sectional view of the steering wheel following an offset plan cut DD of figure 1 without the horn switch and with the safety module housing.

[0043] Detailed description of implementation method(s)

[0044] Figure 1 shows a steering wheel 1 of a vehicle according to the invention. It is covered with a decorative piece 2, fixed to a steering wheel body 10. In a well provided for this purpose, a safety module housing 3 is inserted, covered by a safety module cover 4.

[0045] Figure 2 shows a steering wheel well arranged at the level of a steering wheel hub of the vehicle shown in Figure 1, to receive a safety module housing 3. One or more elastic retaining elements 11, for example elastic bands, are arranged to lock the safety module housing 3 onto the steering wheel body 10, particularly depending on the mounting direction of the safety module housing 3, and to retain the safety module housing 3 in the event of deployment of a safety module airbag. Four horn switches 40 are distributed around the periphery of the well. The switches 40 are connected to each other and to a vehicle wiring harness by conductors 5.

[0046] Figure 3 shows a horn switch 40 comprising: - a 401 push button, - a movable contact 4010 mounted on the push button 401, - a static contact 402, - an elastic element 404, - a 405 switch body. The horn switch 40 is a normally closed switch. Specifically, when cover 4 is in its rest position, the The moving contact 4010 is in electrical contact with the static contact 402. When the cover 4 is in an activated position, the push button 401 is moved in a direction z, the elastic element 404 is compressed, the electrical contact is broken, and the audible alarm can be activated by detecting the opening. The elastic element 404 is arranged to return the push button 401, the moving contact 4010, and the cover 4 to their rest position by extending. The push button 401 is connected to the switch body 405, in which it slides. The switch body 405 is provided with a switch hook 4050, allowing it to be held loosely against the decorative piece 2 during assembly or transport; the precise centering of the switch body 405 on the decorative piece 2 is ensured by the elastic element 404.The retention of the elastic element 404 is facilitated by grooves 4040 arranged on an outer surface of the elastic element 404. The outer surface of the elastic element 4040 further includes a contact surface arranged to come into contact with a stop 4011 belonging to the pusher 401, in the direction z.

[0047] Figure 4 shows the switch 40 mounted on a reference portion 20 of the decorative part 2, without the push button 401 for clarity. The static contact 402 and the moving contact 4010 are each connected to a conductor 5 and are electrically conductive in the rest position shown. The switch 40 is assembled to the decorative part 2 as follows: the elastic element 404 is held without play in the directions normal to the z-direction by projections 200 of the reference portion 20 of the decorative part 2 engaged in grooves 4040 of the elastic element 404. The switch body 405 is held to the reference portion 20 of the decorative part 2 with a switch body clearance J1 in the directions transverse to the z-direction.

[0048] Figure 5 is a cross-sectional view of switch 40 along section plane AA of Figure 4. The push button 401 of switch 40 is fitted (i.e., assembled with a negative clearance) and abutted against the The safety module cover 4 is housed in a cover well 4a, so that the push button 401 follows the same movements as the module cover 4. The push button 401 is arranged to be positioned along the directions transverse to the axis of movement of the module cover solely by the centering of the elastic element 404 (itself positioned by the decorative piece 2), and the guidance of the push button 401 is provided by the switch body 405. The switch body 405 is independent of the centering function (along the directions transverse to the axis of movement of the module cover) of the push button 401, in particular due to the clearance J1 shown in Figure 4.

[0049] When the safety module cover 4 is pressed in the z direction, at least one push button 401 of the switch 40 follows the same movement. The push button 401 compresses the elastic element 404 and slides within the switch body 405. The compressed elastic element 404 exerts a restoring force on the push button 401 in the z direction, centering the push button 401. Specifically, the elastic element 404 is compressed between the stop 4011 of the push button 401 and the switch body 405. The moving contact 4010 attached to the push button 401 disengages from the electrical contact with the static contact 4010, and the audible alarm can be activated upon detection of the electrical circuit interruption.

[0050] Figure 6 shows a cross-sectional view of the safety module along plane BB of Figure 1. It can be seen that the safety module comprises a safety module housing 3, a gas generator 34, and a safety airbag 30. The safety airbag 30 is designed to inflate upon activation of the safety module, under the pressure of the gas released by the gas generator 34. The safety module housing 3 is attached to the steering wheel body 10 by retaining hooks 31 engaged with the elastic retaining elements 11. The mounting plate 12 is attached to the steering wheel body 10 by screws 14 (more clearly visible in Figure 7). The module cover 4 is retained to the safety module housing 3 by a primary hook 32 of the housing 36 inserted into a slot in the module cover 4.

[0051] Figure 7 shows a cross-sectional view along plane CC of Figure 1, without the safety module, and in an embodiment with damping. The plate 12 is fixed to the steering wheel body 10 by screws 14. Damping elements 120 are provided between the screws 14 and the plate 12 to dampen vibrations between the steering wheel body and the safety module. The elastic retaining elements 11 are arranged on a plate 12 that is fixed or nearly fixed relative to the steering wheel body 10 when the damping elements 120 are arranged between the plate 12 and the steering wheel body 10. It should be noted that a significant clearance is provided between the module cover 4 and the safety module housing 3 to allow movement of the safety module housing 3 if dampers 120 are used. In the absence of these dampers 120, such clearance is not necessary.

[0052] Figure 8, in broken section, illustrates a cross-section along successive planes of the line DD shown in Figure 1, passing on one side through the retaining hook 31 on the left of Figure 8 and on the other through a plating surface 33 on the right of Figure 8. The plating surface 33 is formed on the safety module housing 3. An inclined retaining surface 310 on the retaining hook 31 forces the safety module housing 3 downwards in Figure 8, thus pressing the plating surface 33 against the plate 12. This is due to the elasticity of the elastic element(s) 11. The same inclined retaining surface 310 is applicable to the embodiment that does not require a plate 12. In this case, the plating surface 33 can also be arranged to be pressed against the steering wheel body 10 or a frame. Industrial application

[0053] A vehicle steering wheel horn switch according to the present invention, and its manufacture, are capable of industrial application.

[0054] It will be understood that various modifications and / or improvements obvious to a person skilled in the art can be made to the different embodiments of the invention described in this description without departing from the scope of the invention.

[0055] In particular, it can be noted that the means for attaching the switch housing 405 to the reference portion 20 of the decorative part 2, described here under a hook 4050, can be provided in another form, as can the means used to hold the elastic element 404 to the reference portion 20 of the decorative part 2.

Claims

DEMANDS

1. Vehicle steering wheel (1) comprising: - a steering wheel body (10), - a security module, - a module cover (4), movable between a rest position and an activated position relative to the steering wheel body (10) to activate an audible warning, and arranged to at least partially cover the safety module, - at least one horn switch (40) comprising: • a push button (401) attached to the module cover (4), • a movable contact (4010) mounted on the push button (401), • a static contact (402) fixed to the steering wheel body (10), the horn switch being of the normally closed type in the rest position with the moving contact (4010) in electrical contact with the static contact (402), • an elastic element (404) arranged to return the module cover (4) to the rest position, characterized in that the elastic element (404) is arranged to locate the module cover (4) relative to the steering wheel body (10) in at least one direction transverse to a direction (z) of movement of the module cover (4).

2. Vehicle steering wheel (1) according to claim 1, comprising at least one decorative piece (2) fixed to the steering wheel body (10), in which the elastic element (404) is arranged between the pusher (401) and a reference portion (20) of the decorative piece (2).

3. Vehicle steering wheel (1) according to claim 2, the elastic element (404) comprising an external surface and an internal bore, wherein the external surface of the elastic element (404) is in contact with the reference portion of the decorative part (20) and in which the internal bore of the elastic element (404) is in contact with the pusher (401).

4. Vehicle steering wheel (1) according to claim 3, wherein the reference portion (20) of the decorative part (2) comprises three projections (200) and wherein the external surface of the elastic element (404) comprises three grooves (4040), each groove (4040) of the external surface of the elastic element (404) being in contact with a projection (200) of the reference portion (20) of the decorative part (2).

5. Vehicle steering wheel (1) according to any one of claims 2 to 4, in which the module cover (4) covers at least partially the decorative piece (2).

6. Vehicle steering wheel (1) according to any one of claims 1 to 5, comprising at least three switches (40), and preferably four switches (40).

7. Vehicle steering wheel (1) according to any one of claims 1 to 6, in which the pusher (401) is fitted into a cover well (4a), for example during an operation to mount the safety module on the vehicle steering wheel (1).

8. Vehicle steering wheel (1) according to any one of claims 1 to 7, in which a cover-housing clearance between the safety module and the module cover (4) is greater than a cover clearance between the module cover (4) and the decorative piece (2).

9. Vehicle steering wheel (1) according to any one of claims 1 to 8, wherein the elastic element (404) is a part made of elastomer, preferably made of ethylene-propylene-diene monomer elastomer (EPDM), preferably of cylindrical shape.

10. Vehicle steering wheel (1) according to any one of claims 1 to 9, in which the safety module is fixed relative to the steering wheel body (10), directly onto a steering wheel frame, or onto a plate (12) supported by the steering wheel body (10), in particular by permanent contact between at least one retaining hook (31) of the safety module and at least one elastic retaining element (11).

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