Horn device and steering wheel with horn device

Abstract

A horn device in a steering wheel (10) of a vehicle comprises an airbag module (12) which is closed by a module cover (28) which is movably mounted relative to a module housing (30) of the airbag module (12), the horn device (14) comprising at least one horn sensor (16) and an activation element (18) associated with the horn sensor (16). The activation element (18) is arranged opposite the horn sensor (16), and the module cover (28) is fastened to the module housing (30) by means of a plurality of extension springs (34) in such a way that the activation element (18) is loaded towards the horn sensor (16). On the steering wheel (10), the module cover (28) is held in a predetermined position relative to the steering wheel (10) by means of an extension spring (34) and by means of a positioning structure on the steering wheel (10) and / or on the module cover (28).

Description

Field of the Invention

[0001] The present invention relates to a horn device, in particular a horn device in a vehicle steering wheel, and a steering wheel having a horn device. Background Art

[0002] In known arrangement systems, the horn of a vehicle is actuated by pressing on the hub region of the steering wheel. For example, for this purpose, an airbag module - in addition to a module cover that outwardly covers the airbag module - is firmly fixed in the steering wheel, while the module cover is movably supported so that actuation of the horn can be achieved. By moving the module cover, the horn circuit is closed or a horn sensor is actuated. The problem here is to position the airbag module or the module cover in the hub region of the steering wheel such that the clearance required for movement is uniform and as invisible as possible and a moderate and uniform actuation force can also be achieved. Summary of the Invention

[0003] The object of the present invention is to create an improved horn device with which the positioning of the module cover in the steering wheel is simplified.

[0004] The object is solved by a horn device, in particular a horn device in a vehicle steering wheel, which has an airbag module that is closed by a module cover that is movably supported relative to the module housing of the airbag module. The horn device includes at least one horn sensor and an activation element associated with the horn sensor, wherein the activation element is arranged opposite the horn sensor. The module cover is fixed to the module housing via a plurality of tension springs such that the activation element is loaded towards the horn sensor.

[0005] The tension springs enable the module cover to be floatingly supported. However, due to the spring action that pulls the module cover towards the module housing, the module cover can be precisely positioned.

[0006] The module cover is preferably arranged such that it can move in all three spatial directions. For example, the tension springs allow a movement play of a few millimeters in each spatial direction for positioning the module cover relative to the steering wheel.

[0007] Traditional solutions are based on: directly closing the circuit of the horn by mechanical movement of the module cover in order to generate a horn signal. Here, when the actuation of the horn should end, the circuit is usually interrupted by a spring force that resets and points away from the module housing. Therefore, there is always a spring that loads the module cover away from the module housing. These springs are also used to hold the module cover in its initial position.

[0008] However, when using a horn sensor, the force acting on the activation element or the movement of the activation element relative to the horn sensor is detected and the control unit generates a manipulation signal from these sensor values, which is electronically transmitted to the horn unit, and then the horn unit emits a horn sound signal. Here, the following configuration is possible, which manipulates the horn with a significantly smaller displacement movement compared to traditional solutions and accordingly also ends the manipulation with a significantly reduced restoring force. This also enables positioning the module cover via a tension spring instead of a compression spring. Thus, a moderate horn trigger force can also be achieved, which is very uniform over the entire manipulation range.

[0009] There will typically be one or more horn sensors, for example one to four, and associated activation elements, which are distributed on the circumference of the module cover.

[0010] The activation element is preferably arranged on the module cover.

[0011] The horn sensor is preferably connected to a control unit, which detects and processes the sensor signals of the horn sensor and the control unit transmits the manipulation signal to the horn. In this way, reliable triggering of the horn can be achieved even if the driver unevenly loads the module cover. For example, all sensor signals can be electronically averaged to determine whether a manipulation signal is intentionally generated.

[0012] For example, the tension springs are helical springs, which are arranged laterally on the module housing in the manipulation direction. Of course, other types of springs can also be used.

[0013] Preferably, the tension springs are fixed to the module cover and to the module housing. For example, lateral hooks can be arranged on the module housing, and the ends of the respective tension springs on the module housing side are hooked into said hooks. On the module cover side, the tension springs can be fixed in any suitable manner.

[0014] Various arbitrarily suitable types of horn sensors can be used.

[0015] In a first possible variant, the horn sensor is a contact sensor, in particular a pressure sensor, a force sensor or a displacement sensor. Such sensors enable determining the manipulation force with almost no displacement, and this manipulation force can be used by the control unit as a sensor signal for generating a manipulation signal. With such a sensor, the force threshold can be precisely adjusted and can be selected relatively small, from which the pressure or force acting on the module cover should be considered high enough for generating a manipulation signal. In addition, the manipulation force can be determined in a well-reproducible manner.

[0016] In this variant, a tension spring can keep the activation element in contact with the horn sensor in the unoperated initial position of the module cover. Thus, the horn sensor can simultaneously serve as a stop for the module cover for positioning the module cover.

[0017] The activation element is optionally designed to be elastic in order to give the user a haptic feedback when the horn is actuated. In addition, compensation for tolerances and temperature-related length changes can thus be ensured.

[0018] Even in the initial position, i.e., when no additional actuating force acts on the module cover, a force already acts on the horn sensor. This force results, for example, from the tensile force of a tension spring, the self-weight of the module cover, and from the clamping force generated by the assembly position of the module cover. The horn sensor is preferably connected to a control unit which is designed such that it calculates from the actuation signal the force acting on the horn sensor in the initial position. For example, after the airbag module is assembled in the steering wheel, the horn sensor is electronically zeroed, i.e., the force acting on the horn sensor in the initial position is set as an initial value from which the actuation force is detected. The control unit can be the same as the control unit that detects the sensor signal and determines the actuation signal. Thus, it is possible to achieve an accurate and low-displacement or almost displacement-free actuation of the horn for the user when a predetermined force value is exceeded.

[0019] Due to the extremely small displacement distance, an active reset to the initial position by an additional component is generally not necessary and is in particular already achieved by the inherent elasticity of the module cover and / or the horn sensor.

[0020] In another possible variant, the horn sensor is a non-contact sensor, in particular a displacement sensor operating non-contact, such as a capacitive sensor, a resistive sensor, an optical sensor, an acoustic sensor, an inductive sensor or a magnetic sensor. The activation element interacts with the horn sensor in a suitable known manner in order to generate a sensor signal in the horn sensor.

[0021] In the case of a non-contact sensor, the activation element already has a certain distance from the horn sensor in the initial position. During the actuation of the horn, this distance changes, in particular decreases.

[0022] In this variant, the horn sensor is preferably also electronically zeroed after being assembled in the steering wheel, setting the distance between the horn sensor and the activation element in the initial position as an initial value.

[0023] The reset force to the initial position can be provided by an elastic stop element, on which the module cover acts when a manipulation force is applied. The elastic stop element can be a component separate from the activation element and / or from the horn sensor and can be fixed to the module housing or on the steering wheel. Here, the stop element can also limit the movement of the module cover in the manipulation direction. For example, the stop element is made of a suitable elastomer.

[0024] The module cover is preferably fixed to the module housing via a retaining structure which is designed such that when the airbag of the airbag module is activated, the airbag of the airbag module exits through the module cover and the retaining structure confines the module cover to the module housing. Although the module cover is preferably supported in a fully floating manner, the module cover is thus fastened to the module housing in the confined situation. As is conventionally known, the module cover has, for example, a weak zone on the upper side in order to allow the airbag to exit.

[0025] Naturally, the retaining structure should be configured such that it allows the module cover to move for actuating the horn and to be oriented relative to the module housing. For example, the retaining structure is formed by lateral holding hooks on the module housing which engage into laterally dimensioned openings on the module cover.

[0026] When using a pressure sensor or other sensors, in which the activation element contacts the horn sensor when the horn is actuated, the horn sensor should be protected against excessive forces acting, especially during the assembly of the airbag module in the steering wheel. For this purpose, the module cover and the module housing can be designed such that they can be fixed relative to each other in the assembly position via an assembly fixing device, and the assembly fixing device can be released after the airbag module has been assembled on the steering wheel. During the assembly, the assembly is usually carried out by applying a relatively large force in the manipulation direction (so-called overpressure) in order to lock the module housing firmly on the steering wheel, and the assembly fixing device prevents this assembly force from being transmitted to the horn sensor. The assembly fixing device can be removed manually or automatically after the assembly is completed.

[0027] For example, the assembly fixing device has two openings aligned in the assembly position in the module cover and in the module housing and an assembly bolt extending through the two openings. During the assembly, the module cover is mechanically fixed to the module housing via the assembly bolt. Thus, a relative movement relative to the module housing which would cause a force to act on the horn sensor is prohibited.

[0028] The task described above is also solved by a steering wheel having a horn device as described above, wherein the module cover is held in a predetermined position relative to the steering wheel by a tension spring and by a positioning structure on the steering wheel and / or on the module cover. For example, the positioning structure is a cooperating pin, projection, sliding ramp and / or stop on the module cover and on the steering wheel hub. Thus, a reduced tolerance chain and a good gap pattern can be achieved compared to conventional solutions.

[0029] The module housing is preferably firmly and immovably fixed in the steering wheel.

[0030] The horn sensor is preferably immovably fixed to the steering wheel or to the module housing in order to simplify the arrangement of the electrical and electronic connections. Description of the Drawings

[0031] The invention will now be described in more detail with reference to the accompanying drawings on the basis of several embodiments. In these figures:

[0032] Figure 1 A schematic view of a steering wheel according to the invention is shown, which has a horn device according to the invention according to a first embodiment, wherein the horn device is in an initial position;

[0033] Figure 2 Shows the steering wheel when a actuating force acts on the horn device Figure 1 in;

[0034] Figure 3 Shows on the steering wheel in Figure 1 and the positioning structures on the module cover of the steering wheel;

[0035] Figure 4 and Figure 5 Shows the steps when assembling the horn device in the steering wheel;

[0036] Figure 6 Shows the assembly fixing device; and

[0037] Figure 7 A schematic view of a steering wheel according to the invention is shown, which has a horn device according to the invention according to a second embodiment, wherein the horn device is in an initial position. Detailed Description of the Invention

[0038] For reasons of clarity, not all identical parts are always provided with reference numerals in the figures.

[0039] Identical reference numerals (and correspondingly numbers increased by 100) denote identical or substantially identical or functionally identical parts and components in different embodiments.

[0040] Figures 1 to 3Shows a steering wheel 10 having an airbag module 12 installed in its hub region and a horn device 14 according to a first variant.

[0041] The horn device 14 includes a plurality of pairs of horn sensors 16 and associated activation elements 18 located opposite the respective horn sensors 16. The force action on the activation element 18 by the actuating force F is detected by the respective associated horn sensor 16 and transmitted to the control unit 20 (see Figure 2 ), which analyzes and evaluates the sensor signal 22 and thereby generates an actuating signal 24 that ultimately causes an acoustic signal to be emitted from the vehicle horn 26.

[0042] The activation element 18 is arranged on the underside of the module cover 28 of the airbag module 12.

[0043] The module cover 28 is initially supported in a floating manner relative to the module housing 30 of the airbag module 12 via a plurality of tension springs 34. The tension springs 34 exert a pulling force on the module cover 28 towards the module housing 30.

[0044] The tension springs 34 extend along the axial direction A of the module housing 30 and are fixed to the underside of the module cover 28 and on the module housing 30. The fixing on the module housing 30 is effected here via hooks 36, into which one end of the respective tension spring 34 is hooked. In the present example, the tension springs 34 are helical springs.

[0045] In this variant, the horn sensor 16 is a contact sensor, such as a pressure sensor, a force sensor or a displacement sensor, which detects the actuating force F applied to the horn sensor 16 by pressing on the module cover 28 in the actuating direction R. The actuating direction R coincides here with the axial direction A.

[0046] The detection of the actuating force F in the horn sensor 16 takes place with little to almost no displacement. In the present example, the activation element 18 must cross a small gap from the unactuated initial position in order to come into contact with the horn sensor 16. But in Figure 1 the gap marked between the activation element 18 and the horn sensor 16 can also be omitted, and the activation element 18 can already be in contact with the horn sensor 16 in the initial position. In this case, the tension springs 34 keep the activation element 18 in permanent contact with the associated horn sensor 16, i.e. also in the initial position.

[0047] In order to reset the module cover 28 and the activation element 18 to the initial position after actuating the horn, it has been shown that the inherent elasticity of the module cover 28, the activation element 18 and the horn sensor 16 is sufficient. Therefore, no separate reset element against the pulling force of the tension springs 34 is provided here.

[0048] In this example, the horn sensor 16 is firmly fixed at the position on the steering wheel 10.

[0049] The pressure sensor, force sensor, and displacement sensor are very sensitive and can already detect small operating forces F, such that the threshold value for generating an operating signal and thus triggering a horn signal can be selected very low to improve operating comfort. For example, the operating force F required for triggering the horn can be approximately 20 N.

[0050] To prevent distortion of the force determination, the control unit 20 calculates an additional force of interference from the sensor signal 22 here. For example, the tensile force of the tension spring 34, the gravitational force of the module cover 28, and, if necessary, additional permanent forces caused by the positioning of the module cover 28 in the steering wheel 10 are used to determine the output value (offset) by detecting the signal provided by the horn sensor 16 in the initial position and to zero the horn sensor 16 so to speak, in such a way that this output value is continuously calculated from the operating force F.

[0051] In this example, the module cover 28 is movable in all three spatial directions within the range of the tensile force predefined by the tension spring 34. For example, a movement play of a few millimeters can be provided, here approximately 3 millimeters perpendicular to the axial direction A and approximately 5 millimeters in the axial direction A.

[0052] The desired position in the steering wheel 10 is predefined by the positioning structures 38, 40 on the steering wheel 10 and on the module cover 28 (illustrated in Figure 3 and 7 ). The positioning structures 38, 40 are geometric shapes with appropriate mating actions on the steering wheel and on the underside of the module cover 28, such as pins, protrusions, sliding ramps, and / or stops, which firmly predefined the position of the module cover 28 relative to the steering wheel 10 when the airbag module 12 is inserted into the steering wheel 10. No other guiding devices for the module cover 28 are provided here because the module cover 28 only moves a few millimeters when the operating force F is generated.

[0053] Here, the airbag module 12 is designed as is conventionally known such that when the airbag module 12 is activated, the (not shown) airbag of the airbag module 12 exits through the module cover 28 in the axial direction A. To securely retain the module cover 28 on the module housing 30 here, retaining structures 42 are formed on the module housing 30 and on the module cover 28. In the present example, the retaining structure 42 includes laterally projecting retaining hooks 44 on the side wall 46 of the module housing 30 and elongated holes 48 in the side wall 50 on the underside of the module cover 28, wherein the retaining hooks 44 are permanently engaged in the elongated holes 48. The elongated holes 48 are dimensioned such that the entire movement play of the module cover 28 can be exhausted. However, when the airbag module 12 is activated, the retaining hooks 44 contact the edges of the elongated holes 48 and thereby retain the module cover 28 on the module housing 30.

[0054] A plurality of retaining structures 42 are distributed circumferentially on the module cover 28.

[0055] Since in particular pressure, force or displacement sensors are relatively sensitive, in the present example the horn device 14 has an assembly fixing device 52 (see Figures 4 to 6 ).

[0056] The assembly fixing device 52 serves to fix the module cover 28 substantially immovably on the module housing 30 in the axial direction A when the airbag module 12 is assembled in the steering wheel 10.

[0057] This assembly is typically carried out by pushing the airbag module 12 into the hub of the steering wheel 10 in the axial direction A with a relatively large force until the snap connection 54 on the lower end of the module housing 30 opposite the module cover 28 is completed, which firmly positions the airbag module 12 on the steering wheel 10.

[0058] The assembly fixing device 52 here includes two openings 56, 58 that are aligned with each other in the assembled position (see Figure 4 and Figure 6 ) in the side wall 46 of the module housing 30 and in the side wall 50 on the underside of the module cover 28, and an assembly bolt 60 is inserted through these two openings to fix the module cover 28. The diameters of the openings 56, 58 are selected such that the module cover 28 can move substantially not relative to the module housing 30 in the axial direction A as long as the assembly bolt 60 projects through the openings 56, 58. Thus, the forces that occur when the airbag module 12 is assembled in the steering wheel 10 are not transmitted to the horn sensor 16 on the steering wheel 10. After the assembly of the airbag module 12 is completed, the assembly bolt 60 is removed and the movement of the module cover 28 is released. In the present example, two assembly fixing devices 52 are provided respectively on at least two opposite side walls 46, 50 of the module housing 30 and the module cover 28 such that all horn sensors 16 are protected.

[0059] The mounting fixture 52 is arranged laterally to the retaining structure 42 here, respectively.

[0060] Figure 7 A second variant of the steering wheel 10 with a horn device 114 is shown.

[0061] The only difference from the above variant is that here the horn sensor 116 is a non - contact sensor which detects the relative movement of the activation element 118 on the module cover 28 relative to the horn sensor 116.

[0062] Any non - contact sensor can be used as the horn sensor 116, for example a capacitive sensor, a resistive sensor, an optical sensor, an acoustic sensor, an inductive sensor or a magnetic sensor. The activation element 118 is a correspondingly matched component which interacts with the respective sensor to generate a signal.

[0063] Here, the module cover 28 has a play in the axial direction A and thus in the operating direction R, which play is sufficient to enable a relative movement sufficient for precise measurement between the activation element 118 and the horn sensor 116.

[0064] To operate the horn, an operating force F is applied to the module cover 28 in the operating direction R, so that the activation element 118 arranged on the module cover 28 also moves and the distance between the horn sensor 116 and the activation element 118 decreases.

[0065] To move the module cover 28 back into its initial position again, an additional elastic stop element 170 is arranged here on the lower side of the module cover 28, which elastic stop element contacts the steering wheel 10 during the operation of the horn. Of course, the elastic stop element 170 can also be arranged on the steering wheel so that the lower side of the module cover 28 contacts the steering wheel.

[0066] For example, the elastic stop element 170 is made of a suitable elastomer and is so soft that it enables the desired movement of the module cover 28 towards the horn sensor 116 completely, and is so elastic that it causes the module cover 28 to move back completely until its initial position again when the operating force F is cancelled.

[0067] If the displacement of the module cover 28 is large enough for operating the horn, the mounting fixture can be dispensed with in this embodiment. Of course, but when the triggering displacement is small, a mounting fixture can also be provided.

[0068] In a second variant, the horn sensor 116 is optionally arranged on the steering wheel 10 or on the module housing 30. In a first variant, it is more convenient to arrange the horn sensor 16 on the steering wheel 10. However, it is also conceivable to place the horn sensor 16 on the module housing 30.

[0069] All features of the individual embodiments and variants can be freely interchanged or combined with each other within the judgment of a person skilled in the art. In particular, in the first variant, an elastic stop element can also be provided, which protects the horn sensor 16 when the force acting on the module cover 28 is too large. In addition, in both variants, a (not shown) hard stop is optionally provided between the module cover 28 and the steering wheel 10, which absorbs excessive forces and prohibits the module cover 28 from moving beyond a certain extent in the second variant. For example, this hard stop is formed by a rigid projection on the module cover 28 or on the steering wheel 10.

Claims

1. A horn device, especially in a vehicle steering wheel (10), having an airbag module (12) which is closed by a module cover (28) movably supported relative to a module housing (30) of the airbag module (12), the horn device (14) comprising at least one horn sensor (16; 116) and an activation element (18; 118) associated with the horn sensor (16; 116). Wherein, the activation element (18; 118) is arranged opposite to the horn sensor (16; 116), and the module cover (28) is fixed to the module housing (30) via a plurality of tension springs (34) such that the activation element (18; 118) is loaded towards the horn sensor (16; 116).

2. The horn device according to claim 1, wherein, the horn sensor (16) is a contact sensor, especially a pressure sensor, a force sensor or a displacement sensor.

3. The horn device according to claim 2, wherein, the tension spring (34) holds the activation element (18) in contact with the horn sensor (16) in an unoperated initial position.

4. The horn device according to claim 2 or 3, wherein, the horn sensor (16) is connected to a control unit (20) which is designed such that the control unit calculates a force acting on the horn sensor (16) in an unoperated initial position from an actuation signal (24).

5. The horn device according to claim 1, wherein, the horn sensor (116) is a non-contact sensor, especially a capacitive sensor, a resistive sensor, an optical sensor, an acoustic sensor, an inductive sensor or a magnetic sensor.

6. The horn device according to claim 5, wherein, an elastic stop element (170) is provided, and when an actuation force (F) is applied, the module cover (28) acts on the elastic stop element.

7. The horn device according to any one of the preceding claims, wherein, the module cover (28) is fixed to the module housing (30) via a retaining structure (42) which is designed such that when the airbag module (12) is activated, the airbag of the airbag module (12) exits through the module cover (28) and the retaining structure (42) restrains the module cover (28) on the module housing (30).

8. The horn device according to any one of the preceding claims, wherein, the module cover (28) and the module housing (30) are designed such that the module cover and the module housing can be fixed relative to each other in an assembly position via an assembly fixing device (52), wherein the assembly fixing device (52) can be loosened on the steering wheel (10) after the airbag module (12) is assembled.

9. The horn device according to claim 7, wherein, the assembly fixing device (52) has two aligned openings (56, 58) in the module cover (28) and the module housing (30) and an assembly bolt (60) extending through the two openings (56, 58).

10. A steering wheel having a horn device (14; 114) according to one of the preceding claims, wherein, the module cover (28) is held in a predetermined position relative to the steering wheel (10) by a tension spring (34) and by positioning structures (38, 40) on the steering wheel and / or on the module cover (28).

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