阅读说明：本技术 具有用于触发声音输出的节能机电触发装置的车辆方向盘系统 (Vehicle steering wheel system with energy-saving electromechanical triggering device for triggering sound output ) 是由 O·卡岑贝格尔 S·瓦尔 D·吕策尔 M·沙费尔 S·施伦克 于 2020-02-17 设计创作，主要内容包括：本发明涉及一种车辆方向盘系统(1),具有方向盘本体(2),方向盘本体具有用于附接到车辆转向系统的转向轴(10)上的轮毂区域(2b)、具有方向盘轮圈(2a)以及具有用于将方向盘轮圈(2a)附接到轮毂区域(2b)上的至少一个轮辐(2c)；机电触发装置(7),用于通过车辆的声音报警装置触发声音输出,其中,触发装置(7)具有缓冲器盖(8),缓冲器盖布置在方向盘本体(2)上,至少部分地覆盖轮毂区域(2b)并且在这种情况下形成操作表面,其中,缓冲器盖(8)在操作表面上的操作力(F)的作用下在轮毂区域(2b)的方向上以弹性自复位的方式可移动地支承在方向盘本体(2)上和/或者缓冲器盖(8)配置为以弹性自复位的方式可在轮毂区域(2b)的方向上变形；其中,机电触发装置(7)此外具有至少一个力传感器(3a、3b、3c),力传感器被布置在缓冲器盖(8)和方向盘本体(2)之间,缓冲器盖(8)经由力传感器被支撑在方向盘本体(2)上,以测量力值,力值可以与作用在缓冲器盖(8)的操作表面上的操作力(F)相关联；其中,机电触发装置(7)此外对于每个力传感器(3a、3b、3c)包括与相应的力传感器(3a、3b、3c)以导电的方式连接的电子评估系统(4a、4b、4c)和位于这个或这些电子评估系统(4a、4b、4c)的上级的评估单元(9),评估单元(9)可以选择地在节能模式下和在运行模式下运行,其中,电子评估系统(4a、4b、4c)分别经由至少一个数据连接(5a、6a、5b、6b、5c、6c)与上级的评估单元(9)连接,其中,对于每个力传感器(3a、3b、3c)预先规定了一个力值阈值,并且仅仅在力值阈值被至少一个力值超过时,才将唤醒信号经由数据连接传输到评估单元(9),以便评估单元(9)从节能模式切换到运行模式,在运行模式下,借助于由至少一个力传感器(3a、3b、3c)测量的力值确定操作力值(F),以便在必要时,例如在超过预定义的操作力值时,触发车辆的声音报警装置的声音输出。(The invention relates to a vehicle steering wheel system (1) having a steering wheel body (2) with a hub region (2b) for attachment to a steering shaft (10) of a vehicle steering system, with a steering wheel rim (2a) and with at least one spoke (2c) for attaching the steering wheel rim (2a) to the hub region (2 b); an electromechanical triggering device (7) for triggering an acoustic output by means of an acoustic warning device of the vehicle, wherein the triggering device (7) has a damper cover (8) which is arranged on the steering wheel body (2), at least partially covers the hub region (2b) and in this case forms an operating surface, wherein the damper cover (8) is mounted on the steering wheel body (2) such that it can be displaced in the direction of the hub region (2b) in an elastically self-restoring manner under the action of an operating force (F) on the operating surface and/or the damper cover (8) is configured such that it can be deformed in the direction of the hub region (2b) in an elastically self-restoring manner; wherein the electromechanical triggering device (7) furthermore has at least one force sensor (3a, 3b, 3c), which is arranged between the bumper cover (8) and the steering wheel body (2), via which force sensor the bumper cover (8) is supported on the steering wheel body (2) in order to measure a force value, which can be correlated with an operating force (F) acting on an operating surface of the bumper cover (8); wherein the electromechanical triggering device (7) further comprises, for each force sensor (3a, 3b, 3c), an electronic evaluation system (4a, 4b, 4c) which is electrically conductively connected to the respective force sensor (3a, 3b, 3c) and an evaluation unit (9) which is located at the higher stage of the electronic evaluation system(s) (4a, 4b, 4c), wherein the evaluation unit (9) can be selectively operated in a power-saving mode and in an operating mode, wherein the electronic evaluation system (4a, 4b, 4c) is connected to the higher-stage evaluation unit (9) via at least one data connection (5a, 6a, 5b, 6b, 5c, 6c), respectively, wherein a force value threshold value is predefined for each force sensor (3a, 3b, 3c) and only if the force value threshold value is exceeded by at least one force value, the wake-up signal is transmitted via a data connection to the evaluation unit (9) in order for the evaluation unit (9) to switch from the energy-saving mode to an operating mode, in which operating force values (F) are determined by means of the force values measured by the at least one force sensor (3a, 3b, 3c) in order to trigger an acoustic output of an acoustic warning device of the vehicle if necessary, for example if a predefined operating force value is exceeded.)

1. A vehicle steering wheel system (1) comprising:

a steering wheel body (2) having a hub region (2b) for attachment to a steering shaft (10) of a vehicle steering system, having a steering wheel rim (2a) and having at least one spoke (2c) for attaching the steering wheel rim (2a) to the hub region (2 b);

an electromechanical triggering device (7) for triggering a sound output by means of a sound warning device of the vehicle, wherein the triggering device (7) has a bumper cover (8) which is arranged on the steering wheel body (2) and which at least partially covers the hub region (2b) while forming an operating surface, wherein the bumper cover (8) is movably supported on the steering wheel body (2) in an elastically self-resetting manner in the direction of the hub region (2b) under the action of an operating force (F) on the operating surface, and/or the bumper cover (8) is configured to be deformable in an elastically self-resetting manner in the direction of the hub region (2 b);

wherein the electromechanical triggering device (7) further has at least one force sensor (3a, 3b, 3c) which is arranged between the bumper cover (8) and the steering wheel body (2), via which force sensor the bumper cover (8) is supported on the steering wheel body (2) to measure a force value which can be correlated with an operating force (F) acting on an operating surface of the bumper cover (8);

wherein the electromechanical triggering device (7) further comprises, for each force sensor (3a, 3b, 3c), an electronic evaluation system (4a, 4b, 4c) which is electrically conductively connected to the respective force sensor (3a, 3b, 3c), and an evaluation unit (9) which is located at the upper stage of the electronic evaluation system(s) (4a, 4b, 4c), wherein the evaluation unit (9) can be selectively operated in a power-saving mode and in an operating mode, wherein the electronic evaluation system (4a, 4b, 4c) is connected in each case via at least one data connection (5a, 6a, 5b, 6b, 5c, 6c) to the upper-stage evaluation unit (9), wherein a force value threshold value is predefined for each force sensor (3a, 3b, 3c), and only if at least one force value exceeds the force value threshold value, a wake-up signal is transmitted via the data connection to the evaluation unit (9) in order for the evaluation unit (9) to switch from the energy-saving mode to the operating mode in which an operating force value (F) is determined by means of the force values measured by the at least one force sensor (3a, 3b, 3c) in order to trigger an acoustic output of the acoustic warning device of the vehicle when necessary, for example when a predefined operating force value is exceeded.

2. Vehicle steering wheel system (1) according to the preceding claim, wherein one or more force sensors (3a, 3b, 3c) are arranged eccentrically with respect to the steering shaft (10).

3. Vehicle steering wheel system (1) according to one of the two preceding claims, wherein a plurality of force sensors (3a, 3b, 3c) are provided which are distributed around the steering shaft (10), each having an associated electronic evaluation system (4a, 4b, 4c), each being connected with the evaluation unit (9) via at least one data connection.

4. Vehicle steering wheel system (1) according to any of the preceding claims, further having an airbag activation device (11) and the bumper cover (8) being configured for bridging an accommodation space (12), the accommodation space (12) being provided between the hub region and the bumper cover and being provided for at least partially accommodating the airbag activation device (11).

5. Vehicle steering wheel system (1) according to any of the preceding claims, wherein further all electronic evaluation systems (4a, 4b, 4c) can be selectively operated in an energy saving mode and in an operating mode, and a switching of the electronic evaluation systems (4a, 4b, 4c) from the energy saving mode to the operating mode, respectively, is triggered by the evaluation unit (9).

6. Vehicle steering wheel system (1) according to any of the preceding claims, wherein the force sensors (3a, 3b, 3c) measure the force values in an optical, capacitive, inductive or resistive manner, respectively.

7. Vehicle steering wheel system (1) according to one of the preceding claims, wherein the evaluation unit (9) is configured to temporally precede a switch from the operating mode to the energy-saving mode with a switch from the energy-saving mode to the operating mode, and the switch from the operating mode to the energy-saving mode is triggered by each force value having fallen below a predefined shut-off force threshold, preferably by the sum of all force values having fallen below a predefined shut-off total force threshold in each case, more preferably for a predefined duration in each case.

8. Use of a vehicle steering wheel system (1) according to any of the preceding claims in a vehicle.

9. A method for triggering an acoustic output by an acoustic warning device of a vehicle, comprising the steps of:

a vehicle steering wheel system (1) is provided having a steering wheel body (2) with a hub region (2b) for attachment to a steering shaft (10), a steering wheel rim (2a) and at least one spoke (2c) for attaching the steering wheel rim (2a) to the hub region (2 b); having an electromechanical triggering device (7) for triggering an acoustic output by the acoustic warning device of the vehicle, wherein the triggering device (7) has a bumper cover (8) which is arranged on the steering wheel body (2), at least partially covers the hub region (2b) and at the same time forms an operating surface, wherein the bumper cover (8) is movably supported on the steering wheel body (2) in an elastically self-resetting manner in the direction of the hub region (2b) under the action of an operating force (F) on the operating surface, and/or the bumper cover (8) is configured to be deformable in an elastically self-resetting manner in the direction of the hub region (2 b); wherein the electromechanical triggering device (7) furthermore has at least one force sensor (3a, 3b, 3c) which is arranged between the bumper cover (8) and the steering wheel body (2), via which force sensor the bumper cover (8) is supported on the steering wheel body (2); and the electromechanical triggering device (7) further comprises, for each force sensor (3a, 3b, 3c), an electronic evaluation system (4a, 4b, 4c) which is electrically conductively connected to the respective force sensor (3a, 3b, 3c) and an evaluation unit (9) which is located at the higher level of the electronic evaluation system(s) (4a, 4b, 4c), the evaluation unit (9) being able to be selectively operated in a power-saving mode and in an operating mode, wherein the electronic evaluation system (4a, 4b, 4c) is connected in each case via at least one data connection (5a, 6a, 5b, 6b, 5c, 6c) to the higher-level evaluation unit (9), wherein a force value threshold value is predefined for each force sensor (3a, 3b, 3 c);

measuring a force value by means of at least one force sensor (3a, 3b, 3c), which force value can be correlated with an operating force (F) acting on the operating surface of the bumper cover (8);

comparing the force value with the force value threshold, wherein a wake-up signal is transmitted to the evaluation unit (9) via the data connection only if the force value threshold is exceeded by at least one force value;

-switching from the energy saving mode to the operation mode if the wake-up signal is received by the evaluation unit (9);

subsequent operation of the evaluation unit (9) in the operating mode, wherein an operating force value is determined by means of the force value measured by the at least one force sensor;

if necessary, for example when a predefined operating force value is exceeded by the operating force value, triggering of an acoustic output of an acoustic warning device of the vehicle is prompted by the evaluation unit (9).

10. The method according to the preceding claim, wherein further all electronic evaluation systems (4a, 4b, 4c) are selectively operable in a power-saving mode and in an operating mode, and at least one switching of the electronic evaluation systems (4a, 4b, 4c) from the power-saving mode to the operating mode, respectively, is triggered by the evaluation unit (9), preferably before the operating force value is determined in the operating mode of the evaluation unit (9).

11. Method according to either of the two preceding claims, wherein the force sensors (3a, 3b, 3c) measure the force values in an optical, capacitive, inductive or resistive manner, respectively.

12. Method according to any one of the preceding claims 9 to 11, wherein the switching from the operating mode to the energy-saving mode is preceded in time by a switching from the energy-saving mode to the operating mode, and the switching from the operating mode to the energy-saving mode is triggered by each force value having fallen below a respective predefined cut-off force threshold, preferably by the operating force value having fallen below a predefined cut-off operating force threshold in each case, more preferably for a predefined duration in each case.

Technical Field

The invention relates to a vehicle steering wheel system having an energy-saving electromechanical triggering device for triggering an acoustic output by an acoustic warning device of a vehicle, i.e. for example for outputting an acoustic horn signal by a horn of the vehicle. A vehicle steering wheel usually has a hub region (also referred to simply as a hub) for fastening to a steering shaft, a steering wheel rim and at least one spoke for attaching the steering wheel rim to the hub region.

Background

In this case, a damper cover, which covers the hub of the steering wheel, usually forms the operating surface for the electromechanical push button, wherein the damper cover is supported in such a way that it can be pressed down to trigger the horn. Such triggering should be effected only in the case of a purposeful operation with a well-defined aim and not in the case of accidental contact. There is a need for more reliable and accurate triggering by electromechanical triggering means. The increased expenditure for determining the operating force, which is to be carried out electronically and, if appropriate, in software, is thus in conflict with the fundamental requirement for energy saving, in particular if the vehicle is driven at least temporarily by rechargeable batteries.

Disclosure of Invention

The present invention is therefore based on the object of providing a vehicle steering wheel system with an energy-saving electromechanical triggering device for triggering an acoustic output (horn signal) by means of an acoustic warning device of the vehicle. According to the invention, the object is achieved by a vehicle steering wheel system having the features of claim 1. An equally advantageous use and a corresponding method are the subject matter of the respective independent claims. It should be noted that the features and measures listed individually in the following description can be combined with one another in any technically meaningful way and represent further embodiments of the invention. The description particularly refers to the accompanying drawings and detailed description of the present invention.

The vehicle steering wheel system according to the present invention has a steering wheel body, which is also simply referred to as a steering wheel. The steering wheel body has a hub region which is designed for fastening on a steering shaft which is arranged fixedly in a so-called steering column, a steering wheel rim and at least one spoke for attaching the steering wheel rim to the hub region. In this case, the steering wheel rim forms the gripping surface of the steering wheel, but is usually not necessarily designed as a closed ring. Thus, an embodiment according to the invention is also conceivable in which the steering wheel rim forms only a part of the ring. For example, in one embodiment the steering wheel rim forms a so-called single spoke-carried steering wheel horn as a gripping surface, or in another embodiment forms a semi-circle to three-quarters circle, wherein the semi-circle to three-quarters circle is carried by one, two or more spokes.

The vehicle steering wheel according to the invention preferably has an airbag activation device. The airbag activating device includes, for example, an airbag (also referred to as an "airbag"), an airbag holder, a generator for generating gas for filling the airbag, and a generator support.

According to the invention, an electromechanical triggering device is also provided for triggering the sound output by means of a sound warning device of the vehicle. The triggering device provided according to the invention has a bumper cover (also referred to simply as "cover") which is arranged on the steering wheel body and in this case at least partially covers the hub region and in this case forms the operating surface. In one embodiment, the bumper cover is used to receive a fixed airbag actuation device. Preferably, however, the bumper cover is designed in such a way that it bridges a receiving space which is provided between the hub region and the bumper cover and is provided for at least partially receiving the airbag starting device.

For example, the airbag actuation device is fastened either only to the bumper cover or only to the steering wheel body, in particular to the hub region. According to the invention, the bumper cover is movably supported on the steering wheel body, such as the steering wheel hub, in an elastically self-resetting manner in the direction of the hub region under the action of an operating force on the operating surface, and/or the bumper cover is configured to be deformable in the direction of the hub region in an elastically self-resetting manner.

According to the invention, the electromechanical triggering device furthermore has at least one force sensor which is arranged between the bumper cover and the steering wheel body, for example the hub region, via which the bumper cover is supported on the steering wheel body for measuring a force value which can be correlated with an operating force acting on an operating surface of the bumper cover. The force sensor is arranged, for example, eccentrically with respect to the steering shaft, i.e. laterally offset with respect to an axis defined by the steering shaft.

According to the invention, the electromechanical triggering device further comprises, for each force sensor, an electronic evaluation system which is connected to the force sensor in an electrically conductive manner. An electronic evaluation system is to be understood as an electronic circuit, for example as an integrated electronic circuit, which serves to provide a force value which is obtained by means of the force sensor and is proportional to the corresponding operating force. Furthermore, an evaluation unit, preferably exactly one evaluation unit, is provided, which is located at a higher level than the electronic evaluation system or systems and can be operated selectively in the energy-saving mode and in the operating mode. A power-saving mode is understood to be, for example, a mode in which the processor clock and/or the processor supply voltage of at least one processor belonging to the evaluation unit is reduced compared to the operating mode, compared to the operating mode. Preferably, the energy-saving mode is characterized in that the exchange of data via the data connection between the at least one force sensor and the evaluation unit is reduced, more preferably limited to the transmission of a wake-up signal. Energy can be advantageously saved by the energy saving mode according to the invention.

In one embodiment, the evaluation unit is one of the electronic evaluation systems belonging to the force sensor, wherein the electronic evaluation system is operated as a master and the remaining electronic evaluation systems are operated as slaves. Due to the hierarchical structure, the electronic evaluation system of each force sensor is connected to the superordinate evaluation unit via a data connection, for example a data bus (I2C bus). According to the invention, a force value threshold is predefined for each force sensor. If at least one force value threshold value is exceeded by one of the force values, a wake-up signal is transmitted to the evaluation unit via the data connection, for example as an interrupt, if necessary via a separate interrupt line, in order for the evaluation unit to switch from the energy-saving mode to an operating mode in which the operating force value is determined by means of the force value measured by the at least one force sensor in order to trigger a sound output of a sound warning device of the vehicle if necessary, for example if a predefined operating force value is exceeded.

The temporally preceding switching from the operating mode to the energy saving mode takes place, for example, when each force value has fallen below a predefined shut-off force threshold value predefined for each force sensor, for example the sum of all force values has fallen below a predefined total shut-off force threshold value, more preferably the determined operating force has fallen below a predefined operating force threshold value. Preferably, the switch to the energy saving mode is triggered only if each of the force values remains below the associated trigger force threshold value for a predefined duration of time or the sum of all force values remains below the switch-off total force threshold value for a predefined duration of time, or the operating force remains below the predefined switch-off operating force threshold value for a predefined duration of time. In one embodiment, the switching-off force thresholds each correspond to a predefined force threshold for determining a switch to the operating mode.

Preferably, a plurality of force sensors distributed around the steering shaft are provided, which have associated electronic evaluation systems, which are each connected to an evaluation unit via a data connection in order to increase the accuracy of the operating force determination.

Preferably, the electronic evaluation system of each force sensor can be selectively operated in a power-saving mode and in an operating mode. In this case, a switchover of the electronic evaluation system from the energy-saving mode to the operating mode, in which the force value is determined, can furthermore be triggered by the evaluation unit.

Preferably, at least two, for example three, force sensors are provided.

Preferably, the force sensor is designed to measure the force value in an optical, capacitive, inductive or resistive manner. Preferably, a force sensor is used which measures optically. For example, an optical reflectometry method is used in which the light intensity or the propagation time of light varies with the force to be measured.

In one embodiment, the vehicle steering wheel system according to the invention comprises an acoustic warning device for outputting an acoustic warning signal.

The invention furthermore relates to the use of the vehicle steering wheel system in the above-described embodiments in a vehicle, in particular in a motor vehicle.

The invention further relates to a method for triggering an acoustic output by an acoustic warning device of a vehicle, comprising the following steps:

in the step of providing, a vehicle steering wheel system is provided. The system has a steering wheel body. The steering wheel body includes a hub region for attachment to a steering shaft of a vehicle steering system, a steering wheel rim, and at least one spoke for attaching the steering wheel rim to the hub region. Preferably, an airbag activation device is furthermore provided.

According to the invention, an electromechanical triggering device is provided to trigger the sound output by means of a sound warning device of the vehicle. The triggering device provided has a bumper cover which is arranged on the steering wheel body and at least partially covers the hub region and in this case forms the operating surface. Preferably, the bumper cover bridges an accommodation space which is provided between the hub region and the bumper cover and which is provided for at least partially accommodating the airbag starting device.

According to the invention, a bumper cover is provided which is movably supported on the steering wheel body in the direction of the hub region in an elastically self-resetting manner under the action of an operating force on the operating surface, and/or which is configured to be deformable in the direction of the hub region in an elastically self-resetting manner. According to the invention, the electromechanical triggering device furthermore has at least one force sensor, which is arranged between the damper cover and the steering wheel body, the damper cover being supported on the steering wheel body by means of the force sensor. The electromechanical triggering device furthermore has an electronic evaluation system which is connected to the force sensors in an electrically conductive manner for each force sensor, and has one, preferably exactly one, evaluation unit which is located at a higher level of the electronic evaluation system or systems and which can be operated selectively in a power-saving mode and in an operating mode, wherein the electronic evaluation system is connected to the higher-level evaluation unit via a data connection, and a force value threshold value is predefined for each force sensor.

In the measuring step, a force value is measured by means of at least one force sensor, which force value can be correlated with an operating force acting on an operating surface of the bumper cover. In the case of multiple force sensors, multiple force values are measured.

In the comparison step, the force values are compared with the respective associated force value threshold values, wherein a wake-up signal, also referred to as wake-up signal, is transmitted to the evaluation unit via the data connection only if the force value threshold value is exceeded by at least one force value.

The wake-up signal triggers a switch from the power-saving mode to the operating mode as soon as it is received by the evaluation unit.

Subsequent operation of the evaluation unit in a running mode, in which an operating force value is determined by means of the force value measured by the at least one force sensor;

if necessary, the evaluation unit causes the triggering of an acoustic output of an acoustic warning device of the vehicle, for example when a predefined operating force value is exceeded by the operating force value.

Preferably, provision is made for all the electronic evaluation systems to be able to be operated selectively in the energy-saving mode and in the operating mode, and for the evaluation unit to trigger at least one switching of the operating mode of the electronic evaluation system from the energy-saving mode to the operating mode in each case, more preferably before the operating force value is determined in the operating mode of the evaluation unit.

For example, a switching of the electronic evaluation system from the operating mode to the energy-saving mode can also be triggered by the evaluation unit. More preferably, the electronic evaluation system can in each case be switched independently from the operating mode to the energy-saving mode.

According to a preferred embodiment of the method according to the invention, the force sensors are each configured to measure the force values in an optical, capacitive, inductive or resistive manner.

Provision is preferably made for the switchover from the operating mode to the energy-saving mode to be preceded in time by a switchover from the energy-saving mode to the operating mode, and for the switchover from the operating mode to the energy-saving mode to be triggered by each force value having fallen below a respective predefined shut-off force threshold value, preferably by the operating force value having fallen below a predefined shut-off operating force threshold value, more preferably in each case for a predefined duration.

Drawings

The technical environment of the invention is explained in more detail below with reference to the drawings. It should be noted that the figures show particularly preferred embodiment variants of the invention, but the invention is not limited to these embodiment variants. Shown in the attached drawings:

FIG. 1 shows a schematic top view or view of one embodiment of a vehicle steering wheel system;

fig. 2 shows a schematic horizontal section through the embodiment shown in fig. 1; and

fig. 3 shows a schematic diagram of the method according to the invention.

Detailed Description

The vehicle steering wheel system 1 according to the invention has a steering wheel body 2 and an electromechanical triggering device 7. The latter includes a bumper cover 8 disposed on the steering wheel body 2. The steering wheel body 2 has a central hub region 2b for rotationally fixing the steering wheel body 2 to a steering shaft 10, which is usually arranged in a steering column. The steering wheel body 1 furthermore comprises an annular steering wheel rim 2a, which is attached to the hub region 2b by means of a plurality of spokes 2 c. For an operator who operates the vehicle steering wheel system 1, the bumper cover 8 is arranged on the side of the steering wheel body 2 facing the operator in such a manner that the bumper cover 8 covers the boss area 2 b. Below the damper cover 8 and between the damper cover and the steering wheel body 2, more precisely between the damper cover 8 and the hub region 2b, three force sensors 3a, 3b, 3c are arranged, which each determine a force value and which are furthermore used to movably support the damper cover 8 in an elastically self-restoring manner on the hub region 2b of the steering wheel body 2.

The force sensors 3a, 3b, 3c belonging to the electromechanical triggering device 7 serve to trigger an acoustic output, also referred to as a horn signal, by means of an acoustic warning device, not shown, of the vehicle, the triggering being dependent on the operating force. For example, they are optical, capacitive, inductive or MEMS force sensors 3a, 3b, 3 c. The force sensors 3a, 3b, 3c each have an associated electronic evaluation system 4a, 4b, 4c, the latter being connected via a bus (e.g., I2C) as a data connection 5a, 5b, 5c to a superordinate evaluation unit 9. Furthermore, each of the electronic evaluation systems 5a, 5b, 5c is connected to the evaluation unit 9 via an interrupt line 6a, 6b, 6c in order to be able to transmit a wake-up signal from the electronic evaluation systems 4a, 4b, 4c to the evaluation unit 9 or vice versa. The electronic evaluation systems 4a, 4b, 4c send the force values measured by the force sensors 3a, 3b, 3c to the evaluation unit 9 via the buses 5a, 5b, 5c, respectively. The evaluation unit can be selectively operated in a power saving mode and in an operating mode, wherein a switch from the power saving mode to the operating mode is triggered by receiving at least one wake-up signal via the interrupt lines 6a, 6b, 6 c. If the evaluation unit 9 is operated in the operating mode, the force values are further processed electronically and the operating force is determined as a total force and optionally the position of action of the operating force. If the operating force is above the predefined operating force threshold for triggering, the vehicle horn is activated, for example by means of a signal via the vehicle bus or hard wiring.

In order to save energy, at least the evaluation unit 9 and preferably additionally the electronic evaluation system 4a, 4b, 4c of the force sensor 3a, 3b, 3c are, for example, activated during a switch-offThe case is run in a power saving mode, also referred to as a "sleep mode". This means, for example, that only some of the basic functions of the respective component are active. The electronic evaluation system 4a, 4b, 4c is operated, for example, in a sleep mode in such a way that the time interval for the force value determination is increased during the energy saving mode compared to the operating mode. The energy-saving mode is preferably characterized in that no data exchange takes place between the force sensors 3a, 3b, 3c and the evaluation unit 9 via the bus 5a, 5b, 5 c. Fig. 2 shows a vehicle steering wheel system 1 according to the invention in a sectional view. As shown in the figures, the bumper cover 8 is configured to bridge an accommodation space 12 facing the hub region 2b, in which an airbag activation device 11 is accommodated, the airbag activation device 11 being fixed to the hub region 11. The method according to the invention for triggering an acoustic output by an acoustic warning device of a vehicle is explained below with the aid of the schematic illustration in fig. 3. In the step marked with "start", a vehicle steering wheel system is provided, such as described with reference to fig. 1 and 2. In step S1, the vehicle steering wheel system is in an energy saving mode. For each force sensor 3a, 3b, 3c from fig. 1, a force value threshold is predefined. If in step S2 the force value threshold is exceeded in the energy saving mode by one of the force values, which has been determined by the force sensors 3a, 3b, 3c from fig. 1, a wake-up signal is sent in step S3 via the interrupt lines 6a, 6b, 6c to the evaluation unit 9. In step S4, the evaluation unit switches from the energy-saving mode to the operating mode and in step S5 activates all electronic evaluation systems 4a, 4b, 4c of the force sensors 3a, 3b, 3c by means of a corresponding wake-up signal via the bus 5a, 5b, 5c in order to initiate a measurement of the associated force value in step S6 and to transmit it to the evaluation unit 9. The evaluation unit determines the operating force F in step S7 if the operating force F is above the operating force threshold F in step S8_SchwelleThen the horn, i.e. the audible alarm signal, is activated. If the operating force threshold F_SchwelleNot exceeding the predefined duration, the evaluation unit 9 and in particular the electronic evaluation system 4a, 4b, 4c are put back into the energy-saving mode.