Switching unit in a vehicle steering wheel

Abstract

The invention relates to a switching unit (12) in a vehicle steering wheel (10) that can be actuated by the action of a force in an actuation direction (R) and comprises an upper housing unit (16) which can be pressed from the outside, a lower housing unit (18) which is spaced apart from the upper housing unit, at least one elastic restoring element (14) between the upper and lower housing unit (16, 18), and a sensor (20). The restoring element (14) can be moved into a compressed position and moves itself and the upper housing unit (16) back into a starting position without the action of external force. A distance (d) of the restoring element (14) into the compressed position is limited by mechanical stops (36, 38). When the switching unit (12) is actuated, the sensor (20) generates a sensor signal (Si). The sensor (20) is integrated into the at least one restoring element (14).

Description

[0001] Control unit in a vehicle steering wheel

[0002] The invention relates to a switching unit in a vehicle steering wheel.

[0003] Many vehicle functions can now be operated from the steering wheel as standard. This includes activating the horn, but also, for example, controlling multimedia applications.

[0004] Switching units for such functions are usually located on a sliding gas spring module mounted in the hub area or on a switch on a spoke of the steering wheel. To activate the switching unit, the driver presses on an actuating surface on the outside of the steering wheel. This activates, for example, a mechanical switch or closes an electrical circuit, such as a horn circuit, through the mechanical movement. After the switching unit has been activated, the actuating surface must be returned to its unloaded initial position.

[0005] Both the actuation and the resetting should be performed with sufficient accuracy, which usually makes the switching unit complex and therefore expensive.

[0006] The object of the invention is to improve a switching unit and, above all, to make it more cost-effective and more flexible in its application.

[0007] This task is accomplished by a switching unit in a vehicle steering wheel, which can be actuated by a force in one direction and comprises an externally pressed upper housing unit, a spaced-apart lower housing unit, at least one elastic return element between the upper and lower housing units, and a sensor. The return element is designed such that it can be moved into a compressed position by the force applied to the upper housing unit and returns itself and the upper housing unit to a starting position without any external force being applied. The travel distance of the return element into the compressed position is limited by mechanical stops. The sensor is designed to generate and output a sensor signal when the switching unit is actuated and is integrated into the at least one return element.This achieves a functional separation between generating a restoring force for a return movement and generating a signal to actuate the vehicle function. The return element provides only the restoring force to return the upper housing unit to its initial position but does not contribute to signal generation, i.e., it does not close an electrical circuit. The sensor generates only the sensor signal to trigger the desired vehicle function but does not generate any restoring force for the upper housing unit. The sensor can output any suitable digital sensor signal that does not simply open or close an electrical circuit in an on / off switch, thus enabling flexible control of a wide range of vehicle functions.

[0008] Accordingly, it is also possible, for example, to implement a higher force threshold for the sensor than for the movement of the upper housing unit. The switching unit can then be designed so that the upper housing unit is first pressed down completely over its entire travel distance, and only then is the sensor signal generated. This increases the precision with which the vehicle function is triggered and improves the haptic experience for the driver. Furthermore, this also allows the use of a sensor that outputs a multi-stage signal, such as a sensor signal that increases with increasing pressure. This allows, for example, a gradual change in volume or brightness.

[0009] Therefore, in the reset element, the reset and the signal generation can also be spatially separated.

[0010] In general, the sensor for signal generation and the reset element for generating the reset movement can be optimized separately.

[0011] Furthermore, it is possible to standardize the reset elements. For different applications that require, for example, different reset forces or return strokes, reset elements with the same geometry but differently flexible materials and / or differently positioned stops can be used. Similarly, sensors can be integrated into the reset element that are optimally suited to the respective vehicle function without having to change the geometry and reset function of the reset element.

[0012] For example, individual return elements can also be used instead of the continuous silicone mats used previously.

[0013] Normally, the reset element has no electrical contacts.

[0014] The upper housing unit can be part of an outer surface of the vehicle steering wheel and, for example, include an actuation surface for the vehicle function to be triggered, which is directly accessible to the driver. However, the upper housing unit can also be located below another sliding component within the vehicle steering wheel. An example of this is a throttle module that is floating in a hub of the steering wheel and can be pressed down to activate the horn.

[0015] In one version, the lower housing unit is part of the steering wheel's frame. In another version, it is a separate component, for example, a rigid shell with a receptacle for the return element, whereby this component can be firmly and immovably connected to the steering wheel frame.

[0016] According to one aspect, one of the stops is located on the upper housing unit, and this stop determines the travel distance of at least one return element. The stop on the upper housing unit can be easily manufactured from a rigid material, allowing the travel distance during compression of the return element to be precisely adjustable and maintained, even if the return element itself is made of an elastic material. This eliminates the need to integrate rigid stops into the return element, simplifying its manufacture and saving costs.

[0017] For example, the stop is formed on a dimensionally stable projection on the upper housing unit, and at least one return element has a through-opening through which the dimensionally stable projection extends. A positive fit can easily be established between the dimensionally stable projection and the through-opening, so that, firstly, a relative position between the return element and the upper housing unit is reliably maintained, and secondly, the upper housing unit and the return element are securely and precisely connected to each other.

[0018] The dimensionally stable projection can, for example, extend from the underside of the upper housing unit and be directed towards the vehicle's steering wheel.

[0019] The at least one return element can have an elastic compression section that can be compressed in the direction of actuation and thus in the direction of force application by the distance traveled, and a connecting section adjoining the compression section in which the sensor is housed. The return force can thus be provided solely by the compression section, and the connecting section of the return element surrounding the sensor can be designed to be so robust that it is essentially not deformed by the actuation force.

[0020] The return element can be made in one piece, so that the compression section and the connecting section are joined together in one piece and manufactured together, optionally from the same material.

[0021] The compression section is normally facing the lower housing unit and the connecting section the upper housing unit.

[0022] Optionally, an annular radial inner wall is arranged within a radially outer wall of the compression section to achieve more controlled deformation and greater stability of the compression section. The compressibility of the compression section can be achieved, for example, by a cup, bell, or dome shape. For instance, the compression section is cup-shaped, and the connecting section extends from the compression section.

[0023] If the through-hole extends through the connecting section, a central arrangement of the stop in the return element can be easily achieved. For example, the dimensionally stable projection extends into a recess formed within the compression section, such as radially within the radially inner wall. The dimensionally stable projection can also be flush with the top surface of the recess. Because the dimensionally stable projection lies freely within the compression section, the contact between the stop and a counter-stop is not obstructed by the return element itself.

[0024] The counter-attack, for example, also protrudes into this free space, so that the dimensionally stable projection comes into unimpeded contact with the counter-attack after the predetermined distance has been covered.

[0025] The deformation of the compression section can continue until the two stops are abutting each other.

[0026] When mounting the return element on the steering wheel, it is possible to pre-tension the compression section in the direction of actuation in order to adjust the travel distance to the compressed position between the stops. This allows, for example, the compensation of component tolerances.

[0027] The specified travel distance can be set very precisely and easily adapted to current conditions by adjusting the length of the dimensionally stable projection, the height of the counter-stop, and, if necessary, a pre-tension of the compression section of the return element.

[0028] The counter-stop is optionally formed on the lower housing unit, and can therefore also be located directly on the steering wheel frame.

[0029] The reset element and the sensor are connected in such a way that they cannot be separated without damage. For example, the reset element can be made of an elastic material, such as an elastomer, and the sensor can be embedded in the material of the reset element, for example, cast in or overmolded with the material. The sensor is manufactured separately and only integrated into the reset element during its production.

[0030] It is possible to adjust the sensor, for example by choosing a suitable force threshold, so that a sensor signal is only generated after contact of the stops, i.e. only after the return element has been compressed by the entire predetermined distance.

[0031] The reset element is connected to the upper and / or lower housing unit, for example, by a clip or plug connection.

[0032] It is possible that the lower housing unit, optionally the steering wheel frame, has a receptacle for the compression section, such as the radial outer wall, of the return element, into which the return element can be inserted and, if necessary, locked in place.

[0033] In one aspect, the switching unit is mounted on the steering wheel frame via at least one return element.

[0034] Several reset elements can be arranged spatially spaced apart on the inside of the upper housing unit, for example in the case of a large-area upper housing unit such as a gasbag module.

[0035] Here, in addition to at least one reset element with an integrated sensor, it is also possible to use one or more further reset components that consist of a reset element without an integrated sensor, i.e., only a compression section and a connecting section. These reset components have only a reset function, but no actuation function; however, their compression section and connecting section can be manufactured in the same way as those of the reset element and have the same dimensions.

[0036] The sensor could be, for example, a pressure sensor, a strain gauge, a conductivity sensor, an inductive sensor, or a capacitive sensor. Of course, other suitable types of sensors can also be used that can detect pressure on the upper housing unit or contact between a human hand and the upper housing unit. Similarly, several sensor types can be combined in a single reset element.

[0037] To precisely detect the force acting on the upper housing unit, the sensor has, for example, a trigger arm that protrudes from the reset element, for example radially outwards, and when the upper housing unit is pressed, comes into contact with the upper or lower housing unit and thus transmits force to the sensor, which is detected by the sensor.

[0038] In one aspect, the switching unit includes a control unit that is connected to the sensor and receives the sensor signal. The control unit can easily process the sensor signal and forward it to the corresponding function module in the vehicle, which is to be activated by the switching unit.

[0039] The control unit can be designed to set a sensor threshold, independent of the return element's travel distance. The sensor's sensitivity and trigger threshold for an actuation force, above which a sensor signal is generated, can be easily preset electronically via the control unit. This makes the generation of the sensor signal largely independent of the travel distance and the position of the return element's mechanical stops. The control unit also allows for quick and easy sensor adjustment and individual customization.

[0040] For example, the control unit is designed to activate the vehicle's horn, turn signals, multimedia system, or headlights in response to a sensor signal. Other suitable vehicle functions can, of course, also be operated in this way.

[0041] The invention is described in more detail below with reference to an exemplary embodiment and the accompanying figures. The figures show:

[0042] Figure 1 shows a schematic representation of a vehicle steering wheel with several switching units according to the invention;

[0043] Figure 2 shows a schematic sectional view of a switching unit according to the invention; and

[0044] Figure 3 shows a schematic representation of an upper housing unit of a switching unit according to the invention with several reset elements.

[0045] Figure 1 shows a vehicle steering wheel 10, on whose hub and spokes several switching units 12 for actuating suitable vehicle functions are arranged. One of the switching units 12 is located in the steering wheel hub and is associated with a slidably mounted throttle module. Other switching units 12 on the spokes of the vehicle steering wheel 10 operate, for example, a vehicle multimedia unit or a hazard warning system.

[0046] As shown in Figure 2, the switching unit 12 comprises at least one return element 14, which is arranged between an upper housing unit 16 and a lower housing unit 18, such that the upper housing unit 16 is movable in an actuation direction R towards the lower housing unit 18 by the application of an actuating force F. The return element 14 provides a return force to return the upper housing unit 16 to an unloaded initial position. Figure 2 shows the switching unit 12 in the unloaded initial position of the return element 14.

[0047] Furthermore, the switching unit 12 includes a sensor 20 designed to generate a sensor signal Sj. The sensor 20 is connected to a control unit 22, which receives and evaluates the sensor signal Sj and forwards it to a suitable vehicle module to trigger a suitable vehicle function (not shown).

[0048] The sensor 20 is integrated into the reset element 14, but is a separate, self-contained, and functional component. No other components of the reset element 14 are required to generate the sensor signal Sj.

[0049] Sensor 20 converts, for example, the actuating force F or the touch of an actuating surface by a human hand into the sensor signal Sj. For this purpose, the sensor is designed to be sensitive, for example, to a force acting along the actuating direction R or to a capacitive or inductive change. Sensor 20 can be, for example, a pressure sensor, a strain gauge, a conductivity sensor, an inductive sensor, or a capacitive sensor. Of course, other suitable types of sensors can also be used that can detect pressure on the upper housing unit 16 or touch by a human hand.

[0050] The return element 14 consists of an elastic, compressible compression section 24 and a connecting section 26 integrally connected to the compression section 24. The connecting section 26 is essentially solid, with the exception of a through-opening 28 located centrally within it. The sensor 20 is integrated into the connecting section 26 and does not extend into the compression section 24.

[0051] In this example, the return element 14 is manufactured in one piece from a single elastic material, for example an elastomer.

[0052] The sensor 20 is embedded in the return element 14 during its manufacture, for example by being overmolded with the material of the return element 14.

[0053] In this example, the compression section 24 is approximately pot-, bell-, or dome-shaped and comprises a radially outer wall 30, which here extends circumferentially. Radially inside the radially outer wall 30, there is a radially inner wall 32, which also extends circumferentially. Projected along the direction of actuation R, the radially inner wall 32 surrounds the through-opening 28 and defines a clearance 34 below the through-opening 28.

[0054] The switching unit 12 comprises two mechanical stops 36, 38, which are spaced apart from each other by a predetermined distance d along the actuation direction R. The predetermined distance d limits the compression movement of the return element 14 when the actuating force F is applied and defines a compressed position of the compression section 24.

[0055] In this example, the stop 36 is formed on the upper housing unit 16 and the stop 38 on the lower housing unit 18. Thus, neither stop 36 nor 38 is part of the return element 14.

[0056] In one variant, the compression section 24 is mounted under preload in the switching unit 12, with the predetermined travel distance d being set by the preload. During installation, the compression section 24 is compressed by a certain amount in the actuation direction R, thereby reducing the predetermined travel distance d by the desired amount. This allows, for example, the compensation of component tolerances. In this example, the stop 36 is located on a dimensionally stable projection 40, which extends from an inner surface 42 of the upper housing unit 16 towards the lower housing unit 18. The dimensionally stable projection 40 extends through the through-opening 28 and is, for example, positively engaged in the through-opening 28.

[0057] In the example shown here, the stop 36 is flush with a top surface 44 of the free space 34 in the compression section 24, but it could also protrude into the free space 34.

[0058] The inner surface 42 of the lower housing unit 16 rests here on a top surface 45 of the return element 14, more precisely of the connecting section 26.

[0059] In this example, the stop 38 is formed directly on an inner surface 46 of the lower housing unit 18. In the example of Figure 2, the stop 38 forms a free end of a dimensionally stable projection 48 that extends from the inner surface 46, projects into the clearance 34, and is opposite the stop 36.

[0060] There are no electrical contacts or sensors at stops 36 and 38.

[0061] Both stops 36, 38 are so rigid and dimensionally stable that they do not deform significantly when the actuating force F is applied.

[0062] In this example, the return element 14 is received together with the compression section 24 in a receptacle 50 of the lower housing unit 18. For example, the compression section 24 is secured to the lower housing unit 18 by a clip connection or a plug connection 51 (indicated in Figure 2). Such a connection can be formed, for example, at a lower end of the radially outer wall 30.

[0063] In one variant, the lower housing unit 18 is a separate component from the skeleton of the vehicle steering wheel 10, which can be rigidly connected to the skeleton. In another variant, a section of the skeleton directly forms the lower housing unit 18. As indicated in Figure 2, the switching unit 12 can comprise only a single return element 14.

[0064] In another embodiment, several return elements 14 are arranged on the upper housing unit 16, as shown in Figure 3. In this example, each of the return elements 14 is positively locked to a dimensionally stable projection 40 of the upper housing unit 16.

[0065] It is also possible to use reset components 52 instead of one or more of the reset elements 14. These reset components 52 have a compression section 24 and a connecting section 26 made of an elastomer, analogous to the reset elements 14, but do not include an integrated sensor 20. These reset components 52 have the same geometry as the reset elements 14, but only generate a restoring force and no sensor signal Sj.

[0066] The upper housing unit 16 is mounted here on the lower housing unit 18 via the return elements 14 and, if applicable, the return components 52.

[0067] In one variant, an outer surface 54 of the upper housing unit 16 directly forms an outer surface of the vehicle steering wheel 10. In this case, the outer surface represents an actuation surface for the switching unit 12. Such switching units 12 are, for example, installed on the spokes of the vehicle steering wheel 10.

[0068] In another variant, the upper housing unit 16 is connected to or integrated into another component, for example, a gas bag module. In this case, the upper housing unit 16 is located inside the vehicle steering wheel 10, below the other component. This variant is used, for example, with gas bag modules that are slidably mounted. The upper housing unit 16 is then attached to the underside of the gas bag module, or the underside of the gas bag module directly forms the upper housing unit 16.

[0069] In the variant shown in Figure 2, the sensor 20 comprises a release arm 56 that projects from the return element 14 and extends radially beyond the connecting section 26. The release arm 56 can interact with a suitable dimensionally stable structure on the upper housing unit 16. When the actuating force F is applied, this structure on the upper housing unit 16 comes into contact with the release arm 56 and deforms the release arm 56. This results in a force transmission to the sensor 20, which generates the sensor signal Sj. An arrangement in which the release arm 56 comes into contact with the lower housing unit 18 or another steering wheel-mounted component is also conceivable. It is also possible that the sensor 20 does not project beyond the connecting section 26 and detects the actuating force F internally.

[0070] In the switching unit 12, the reset function is implemented exclusively via the reset element 14, while the generation of the sensor signal Sj is carried out exclusively by the sensor 20.

[0071] The deformation of the restoring element 14, and especially of the compression section 24, can therefore be completely or partially separated from the generation of the sensor signal Sj.

[0072] To actuate the switching unit 12, the driver exerts pressure on the upper housing unit 16 by pressing on an actuating surface on the vehicle steering wheel 10. The actuating force F compresses the compression section 24 and moves the upper housing unit 16 towards the lower housing unit 18. When the upper housing unit 16 has traveled the predetermined distance d, the two mechanical stops 36, 38 come into contact with each other and prevent further movement of the upper housing unit 16.

[0073] The compression of the compression section 24 generates a restoring force which, when the actuating force F decreases, moves the restoring element 14 and thus also the upper housing unit 16 back to the starting position.

[0074] The generation of the sensor signal Sj is independent of the generation of the restoring force. Since the sensor 20 is integrated into the restoring element 14, the actuating force F also acts on the sensor 20 and can be used by it to generate the sensor signal Sj. However, a threshold value So of the sensor 20, above which a sensor signal Sj is generated and output, can be set by the control unit 22, so that the control unit 22 can influence the sensitivity of the sensor 20 with respect to the actuating force F. The threshold value So is therefore independent of the displacement d of the restoring element 14.

[0075] In one variant, the threshold value So is chosen so high that the compression section 24 must be fully compressed and the stops 36, 38 must be in contact with each other before the actuating force F is high enough to trigger a sensor signal Sj.

[0076] In this variant, it is also possible to vary the sensor signal Sj depending on the magnitude of the actuation force F. For example, a higher actuation force F can increase or decrease the volume, or a similar multi-stage sensor signal Sj can be generated for other applications.

Claims

Patent claims 1. A switching unit (12) in a vehicle steering wheel (10), which can be actuated by a force in an actuation direction (R), comprises an externally pressable upper housing unit (16), a spaced-apart lower housing unit (18), and at least one elastic return element (14) between the upper and lower housing units (16, 18) and a sensor (20), wherein the return element (14) is designed such that it can be moved into a compressed position by the force acting on the upper housing unit (16) and moves itself and the upper housing unit (16) back to an initial position without external force, wherein a travel distance (d) of the return element (14) into the compressed position is limited by mechanical stops (36, 38) and the sensor (20) is designed to generate and output a sensor signal (Sj) when the switching unit (12) is actuated, and wherein the sensor (20) is integrated into the at least one reset element (14) is integrated.

2. Switching unit (12) according to claim 1, wherein one of the stops (36) is arranged on the upper housing unit (16) and the stop (36) co-determines the travel distance (d) of the at least one return element (14).

3. Switching unit (12) according to claim 2, wherein the stop (36) is formed on a dimensionally stable projection (40) on the upper housing unit (16) and the at least one return element (14) has a through-opening (28) through which the dimensionally stable projection (40) extends.

4. Switching unit (12) according to one of the preceding claims, wherein the at least one return element (14) has an elastic compression section (24) which can be compressed in the direction of the force by the distance (d), and a connecting section (26) adjoining the compression section (24) in which the sensor (20) is received.

5. Switching unit (12) according to claims 3 and 4, wherein the through-opening (28) passes through the connecting section (26).

6. Switching unit (12) according to claim 4 or claim 5, wherein the compression section (24) is pot-shaped and the connecting section (26) extends from the compression section (24).

7. Switching unit (12) according to one of the preceding claims, wherein the reset element (14) is connected to the upper and / or lower housing unit (16, 18) by a clip or plug connection (51).

8. Switching unit (12) according to one of the preceding claims, wherein several reset elements (14) are arranged spatially spaced apart from one another on an inner side (42) of the upper housing unit (16).

9. Switching unit (12) according to one of the preceding claims, wherein the sensor (20) is a pressure sensor, a strain gauge, a conductivity sensor, an inductive sensor or a capacitive sensor.

10. Switching unit (12) according to one of the preceding claims, wherein the sensor (20) has a trigger arm (56) which protrudes from the reset element (14) and comes into contact with the upper or lower housing unit (16, 18) when the upper housing unit (16) is pressed.

11. Switching unit (12) according to one of the preceding claims, comprising a control unit (22) which is connected to the sensor (20) and receives the sensor signal (Sj).

12. Switching unit (12) according to claim 11, wherein the control unit (22) is designed to set a threshold value (So) of the sensor (20), wherein the threshold value (So) is independent of the travel distance (d) of the reset element.

13. Switching unit (12) according to claim 11 or 12, wherein the control unit (22) is designed to cause the activation of a horn, a turn signal, a multimedia system or a headlight of the vehicle in response to the sensor signal (Sj).

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