Push switch and motor vehicle having a push switch

A push switch and a motor vehicle in which such a push switch is used. The push switch has a push cap, a baseplate, a switch element which is actuatable by the push cap, a first lever, and a second lever. The first lever and the second lever are mounted rotatably on the baseplate by means of bearing blocks and are each connected movably to the push cap at a first lever end. At a second lever end, the first lever and the second lever are connected movably to one another. The first lever and the second lever are designed such that they form mass compensation for the push cap.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application No. DE 10 2018 222 088.3, filed on Dec. 18, 2018 with the German Patent and Trademark Office. The contents of the aforesaid Patent Application are incorporated herein for all purposes.

TECHNICAL FIELD

The present invention relates to a push switch and to a motor vehicle in which a push switch is installed.

BACKGROUND

In modern interior design of motor vehicles, there is an increasing necessity to install relatively large and often heavy elements at a variety of positions in the motor vehicle, which elements should also serve simultaneously as push switches. For example, push switches may be provided in the form of touchscreens, displays, or buttons in the center console, the steering wheel, the doors, the ceiling, or the dashboard with which the vehicle occupants can trigger a desired function with a touch of a finger. It is desirable here for the necessary actuation forces to remain basically the same regardless of the pressure point on the surface of the push switch. For reasons of cost, it is also sought after for the push switches to only have one sensor or element for haptic feedback.

Solutions used for computer keyboards cannot carry large loads such as, for example, 5-inch displays. In addition, larger surfaces begin to tilt such that, with keys like the space bar, the shift key, or the enter key, a shift of the keys perpendicular to the direction of actuation is often visible and sometimes multiple switch elements are required for them to be triggered reliably.

A challenge in the development of large-format push switches is that a large, heavy surface must be mounted such that the push switch can be installed anywhere in the motor vehicle, for example in the center console, the doors, the ceiling, or the dashboard. At the same time, nearly identical actuation forces should always be measurable on the surface during actuation of the push switch regardless of the installation location. In particular when a display is integrated into the push switch, malfunctions or reduced operability can occur due to the additional mass of the display, depending on the installation location.

Further problems can occur when the push-button switch is installed in the motor vehicle such that its direction of actuation is parallel to the direction of travel. Due to acceleration or braking maneuvers, the display experiences acceleration that can lead to movements on the display. A comparable problem occurs when the push-button switch is installed in the center console or in the ceiling and an uneven path is driven. The vibrations occurring in this case propagate through the relatively weakly damped system to the display. In both cases, erroneous triggerings of the switching element can occur.

With lightweight displays or key caps, these effects do not appear since swinging up can be prevented through slight pretensioning of the system and the play in the system can be reduced. Depending on the desired triggering force of the push switch, it must only be ensured that the forces occurring as a result of the acceleration are smaller than the triggering force of the push switch.

SUMMARY

An object exists to provide an alternative structure of a push switch that is suitable for a large-area design and integration of a heavy display.

The object is solved by a push switch with the features of claim1. Embodiments of the invention are the subject matter of the dependent claims and the following description.

DESCRIPTION

According to a first exemplary aspect, a push switch has a push cap, a baseplate, a switch element which is actuatable by the push cap, a first lever, and a second lever, wherein the first lever and the second lever are mounted rotatably on the baseplate by means of bearing blocks, are each connected movably to the push cap at a first lever end and are connected movably to one another at a second lever end, and wherein the first lever and the second lever are designed such that they form mass compensation for the push cap.

The present construction enables a very flat structure of large push switches which can support, for example, a display and function with low triggering forces. The push switches are constructed very simply, cost effective since the two levers can be structurally identical, and at the same time robust against overload. The movable push cap is positioned very well in its resting position via the lever mechanism. In addition, twisting of the movable push cap relative to the direction of actuation may be effectively prevented. In addition, as a result of the lever mechanism and in some embodiments, just one central switch element is required to make a large surface into a push switch. The construction can be installed in any position and functions, even when installed overhead, with nearly the same triggering force without further tuning of the system. The switching function is impervious to additionally occurring accelerations, regardless of their direction. A widely available element may be used as the switch element, for example one of the following elements: a dome switch, a piezo element, an electromagnet, or a vibration element. The solution according to the some embodiments needs only one central switch element for the haptic feedback. To detect a force, this may be, for example, a dome switch, as it is known from computer keyboards. For force feedback, a stroke of the entire push cap counter to the direction of actuation can be generated by means of a piezo element or an electromagnet. For haptic feedback in the form of a vibration, the central switch element can be a vibration element.

In some embodiments, the bearing blocks are arranged such that the levers each have asymmetrical lever arms. The stroke of the push cap can be determined by the selection of the position of the mounting of the levers. Thus, the design of the push switch may be adapted to various applications. The non-identically long lever arms result in a series of benefits. Smaller compensation weights maybe used, as a result of which the required installation space is reduced. At the same time, the mass compensation for acceleration compensation leads only to a reasonable increase in the weight of the push switch. A reduced effect of the play between the lever ends, which are connected movably to one another, on the push cap deviation in the direction of actuation results as a further benefit.

In some embodiments, weights are arranged in or on the levers for mass compensation. Alternatively or additionally, the levers may each have an accumulation of material. The use of weights has the benefit that adding or removing weights enables an adaptation to push caps with different masses. However, an additional work step may be needed for installing the weights. This may be dispensed with if accumulations of material are used for mass compensation, for example thickenings of the lever arms.

In some embodiments, the levers are designed such that their respective centers of gravity are shifted in the direction of the second lever end. Experiments have shown that the mass compensation functions better the farther the centers of gravity of the levers are shifted in the direction of the center of the push switch, i.e., in the direction of the respective second lever end. The center of gravity should in this case lie in the center of the levers in the direction of actuation.

In some embodiments, the first lever end of the first lever and the first lever end of the second lever are connected to the push cap in a play-free manner in the direction of actuation of the push switch. The at least largely play-free connection ensures that the push cap moves with a nearly parallel shift in the direction of the baseplate. Deviations <0.1 mm can be realized in this direction. The position at which a touch of a finger on the push cap takes place does not play a role here.

In some embodiments, the second lever end of the first lever and the second lever end of the second lever are connected to one another by means of involute toothing. Involute toothing is a simple and cost-effective solution for a play-free and frictional connection between the levers in which the levers are in contact with one another at all times. Involute toothing has no additional movable or deformable parts. During assembly, the teeth of the lever ends must merely be put together such that simple assembly is ensured.

In some embodiments, contact surfaces between the levers and the push cap and between the levers and the bearing blocks are formed at least partially as cylindrical rolling surfaces. As a result of the rolling of the levers between the push cap and the bearing blocks of the baseplate instead of sliding, only rolling friction occurs, as a result of which, inter alia, the wear is reduced. In addition, nearly the entire force is transmitted to the switch element during actuation.

In some embodiments, the levers each have at least one driver which hooks into an associated recess in the push cap or the bearing blocks. In this manner, a simple and cost-effective solution for a play-free and frictional connection between the push cap and the levers or between the bearing blocks and the levers is realized. No complicated mechanical joints are required.

In some embodiments, the baseplate has a carrier surface for the levers that determines a resting position. The carrier surface achieves a defined height position of the push cap in the resting position, which is beneficial for an installation of the push switch that is flush with the surface.

In some embodiments, a display is arranged on the push cap. The display can be used to display variable contents on the push switch and thus adapt the push switch to different operating situations. For example, this also creates the possibility of providing large displays with haptic feedback.

In some embodiments, a push switch is used in a vehicle, in particular a motor vehicle. Such a push switch is suitable for practically all operating elements, for example in the ceiling region, in the doors, as a steering wheel button, for a navigation or multimedia system, the operation of the air conditioning system, etc. However, use is not limited to the area of vehicles; in principle, this push switch may be used anywhere where thin buttons, displays, or touchscreens are required and where at the same time haptic feedback is desired.

Further aspects will become apparent from the following description and the appended claims in conjunction with the FIGS.

In order to better understand the principles of the present invention, additional embodiments are explained in greater detail below based on the FIGS.. It should be understood that the invention is not limited to these embodiments and that the features described may also be combined or modified without departing from the scope as defined in the appended claims.

Specific references to components, process steps, and other elements are not intended to be limiting. Further, it is understood that like parts bear the same or similar reference numerals when referring to alternateFIGS.1tis further noted that the FIGS. are schematic and provided for guidance to the skilled reader and are not necessarily drawn to scale. Rather, the various drawing scales, aspect ratios, and numbers of components shown in the FIGS. may be purposely distorted to make certain features or relationships easier to understand.

FIG.1shows a simplified schematic representation of a side view of a push switch1in a resting position. A section along the X-Z plane is shown, wherein Z is the direction of actuation of the push switch1. The push switch1has a push cap2, a baseplate3, a switch element4, a first lever5, and a second lever6. A display14is embedded in the push cap2. In this example, the switch element4is a dome switch. The push cap2is movable, whereas the baseplate3is fixed at the installation location of the push switch1. The switch element4is arranged between the push cap2and baseplate3such that it is actuatable by the push cap2. The two levers5,6are mounted rotatably in the Y-direction on the baseplate3by means of bearing blocks7. For example, the two levers5,6are fixedly positioned in the Z- and X-direction. The bearing blocks7are arranged such that the levers5,6each have asymmetrical lever arms51,52,61,62. The levers5,6each have a cylinder element17and are conditioned such that the cylinder element17can roll between the push cap2and the respective bearing block7. In this case, the length of the long lever arms52,62is for example at least three times as large as the diameter of the cylinder element17.

The movable push cap2is movably connected to one first lever end8of the two levers5,6at each of two opposite sides. For this purpose, the levers5,6have drivers11that pass on the movement of the push cap2in the Z-direction to the cylinder element17. The drivers11engage in corresponding recesses12in the push cap2for this purpose. The recesses12are designed such that there is hardly any play in the Z-direction. The cylinder elements17also have drivers (not shown here) on the opposite side that engage with the bearing blocks7. The first lever5and the second lever6are movably interlocked with one another on a second lever end9such that a rotational movement is transferred from one lever to the other. For example, this connection is free of play in the Z-direction, for example by using involute toothing. The cylinder elements17on the short lever arms51,61ensure that the push cap2is moved at a defined distance to the bearing blocks7and can roll on the vertical surfaces of the bearing blocks7. Thus, only rolling friction arises.

The two levers5,6have weights10that are arranged in or on the levers5,6. Alternatively or additionally, the weights10may also be realized in the form of an accumulation of material in the levers5,6, for example in the form of a thickening. The weights10are selected such that the levers5,6are arranged nearly parallel to the push cap2without any actuation force on the movable push cap2. Deviations in the order of magnitude of approx. 2° with respect to the baseplate3are acceptable since the entire system is pretensioned by the switch element4with approx. 0.2 N and the levers5,6are thus pressed against a carrier surface13. In the case of a dome switch, the pretensioning may be realized, e.g., in that a silicone element of the dome switch is compressed.

Depending on the selected play of the levers5,6and of the push cap2in relation to each other, the push cap2in its resting position is positioned very well in X and Y by the lever mechanism. At the same time, the construction largely prevents twisting of the push cap2about the Z-axis. The levers5,6serve here only for suspension and guidance as well as for mass compensation of the push cap2.

FIG.2shows the push switch fromFIG.1in an actuation position. If the push cap2is moved in the direction of the baseplate3as a reaction to an actuation force, the cylinder elements17on the levers5,6roll in the direction of the baseplate3. At the same time, the levers5,6are set in rotation by the downward movement of the push cap, i.e. the lever ends9, which are interlocked with one another, and the weights10move in the direction of the push cap2. Along with the largely play-free mounting, the interlocking of the levers5,6ensures that the push cap2moves relative to the baseplate3with a nearly parallel shift in the Z-direction, regardless of the position in X and Y at which a touch of a finger on the push cap2takes place. If the angles of the lever rotation have been selected to be small enough, for example smaller than 10°, the torques practically offset each other. In addition, the weights10arranged on the lever system then also only slightly increase the force necessary to actuate the switch element4. As the actuation force of the user rises, the switch element4is increasingly compressed between the push cap2and the baseplate3. It finally collapses when its triggering force has been reached, such that the contact is closed. The triggering force may lie, for example, in the range between 2 N and 6 N.

In the following, embodiments will be described in greater detail with reference toFIGS.3to13.

FIG.3shows a baseplate3of an embodiment of the push switch. The coordinate system used is also shown. In this embodiment, three bearing blocks7are provided for each lever. The bearing blocks7are designed such that recesses12for drivers of the levers are formed. A centrally arranged support surface18for the switch element as well as carrier surfaces13for the two levers are also shown. The carrier surfaces13define a resting position.

FIG.4shows a lever pair of the embodiment of the push switch. In this embodiment, the first lever5and the second lever6are structurally identical, as a result of which production costs can be saved. On a first lever end8, the levers5,6have drivers11, which, in the assembled state of the push switch, interact with corresponding recesses in the push cap and thus establish the movable connection to the push cap. On a second lever end9, the levers5,6have teeth19, by means of which the movable, play-free connection between the levers5,6is realized. Weights10, for example made of metal, are attached to the levers5,6. These weights may be, for example, screwed or adhered to the levers5,6. The levers5,6have openings20with which the bearing blocks engage. Drivers11are also arranged in the openings20. The drivers interact with the bearing blocks in the assembled state of the push switch. The drivers11have cylindrical surfaces so that the drivers11can roll between the push cap and the bearing blocks.

FIG.5shows the baseplate3fromFIG.3with the installed lever pair fromFIG.4. The levers5,6lie on the bearing blocks7and are held in the recesses in the bearing blocks7by the drivers. In addition, the teeth19of the two levers5,6engage with each other such that a frictional, movable connection between the levers5,6exists.

FIG.6shows a push cap2of the embodiment of the push switch. The push cap2is shown in a view from below, i.e. the push cap2has been rotated about the Y-axis by 180°. Recesses12that interact with the drivers at the respective first lever end of the levers and establish a movable connection to the levers are arranged on the long edges of the push cap2. Furthermore, the switch element4is centrally arranged inside the push cap2.

FIG.7shows an example of the fully assembled push switch1. In this example, the push cap2is shown transparent. In the assembled state, the push switch1has a width of 135 mm in the X-direction, a depth of 250 mm in the Y-direction, and a height in the resting position of 47.5 mm in the Z-direction. The height in the Z-direction for the lever mechanism takes up approx. 6 mm with a stroke of the push cap2of ˜0.5 mm. With a total weight of the push switch1of 1700 g, the weight of the push cap is 770 g. In this case, twelve weights10to each 5 are arranged on each lever5,6. In addition, four sectional planes A-A, B-B, C-C, and D-D are marked in the figure and are shown inFIG.8toFIG.12.

FIG.8shows a first section through the push switch1fromFIG.7along the X-Z plane in the region of the sectional plane A-A. In the representation shown, the section runs more or less through the center of the front bearing blocks7. The cylindrical design of the short lever arms51,61can be seen well. The resulting cylindrical running surfaces on the levers5,6roll along the contact surfaces15with the push cap2and along the contact surfaces16with the bearing blocks7of the baseplate3. These cylindrical running surfaces are present in all four corners of the construction. The teeth19, formed as involute toothing, of the two levers5,6engage with each other and thus form a movable, frictional connection between the levers5,6. This ensures that the push cap2cannot tilt during actuation.

FIG.9shows a second section through the push switch1fromFIG.7along the X-Z plane in the region of the sectional plane B-B. In the representation shown, the section runs approximately through the front third of the front bearing blocks7. The two levers5, lie near the cylindrical rolling surfaces with their inner drivers11on lower abutment surfaces22of the bearing blocks7. The push cap2lies near the cylindrical rolling surfaces on the lever5,6with upper abutment surfaces23on the outer drivers11of the levers5,6. The inner and outer drivers11are present on all cylindrical running surfaces of the construction. The weights10are selected and positioned such that the weight of the push cap2is compensated via the levers5,6and the system is nearly in equilibrium. The center of gravity21in the Z-direction should in this case be approximately in the center of the levers5,6.

FIG.10shows a third section through the push switch1fromFIG.7along the X-Z plane in the region of the sectional plane C-C. In the representation shown, the section runs approximately through the rear third of the front bearing blocks7. Near the cylindrical rolling surfaces, the inner drivers11of the levers5,6hook under upper abutment surfaces24of the bearing blocks7. Near the cylindrical rolling surfaces, the outer drivers11of the levers5,6lie on lower abutment surfaces25of the push cap2. The inner and outer drivers11are present on all cylindrical running surfaces of the construction. In comparison to the section B-B shown inFIG.9, the drivers11here engage exactly oppositely.

FIG.11shows a fourth section through the push switch1fromFIG.7along the X-Z plane in the region of the sectional plane D-D. In the representation shown, the section runs through the center of the switch element4. The push switch1is shown in a resting position. Near the cylindrical rolling surfaces, the inner drivers11of the levers5,6hook under upper abutment surfaces24of the bearing blocks7. Near the cylindrical rolling surfaces, the outer drivers11of the levers5,6lie on lower abutment surfaces25of the push cap2. The push cap2rests on the levers5,6. The levers5,6do not lie exactly horizontal, but at an angle of approx. −1°. They lie on the carrier surfaces13. The silicone of the switch element4is compressed by 0.1 mm, as a result of which the system is pretensioned.

FIG.12shows the fourth section through the push switch1fromFIG.7along the X-Z plane in an actuation position. The push cap has been pressed and moved 0.5 mm in the direction of the baseplate3. The long lever arms52,62have moved in the direction of the push cap2. The push cap has been guided nearly parallel by the levers5,6. In the actuation position, the levers5,6also do not lie horizontal, but at an angle of approx. 1°. During the actuation, the silicone of the switch element4is compressed between the push cap2and the support surface18of the baseplate3by approx. 0.5 mm. The dome in the switch collapses in the process.

When the pressure on the push cap2lessens, the silicone relaxes again and the dome switch springs back to its starting position. Therefore, no additional spring is necessary to reset the push cap2. The mass compensation by the levers5,6and the weights10, which compensates for the weight of the push cap, and the rolling design of the cylinder elements on the levers5,6, which considerably reduce the friction in the system, are primarily responsible for this.

FIG.13schematically shows an interior of a motor vehicle30, in which push switches1according to the present teaching are installed. A first push switch1with display14is arranged in a dashboard31of the motor vehicle30, for example to operate an infotainment system. Another considerably smaller push switch1is installed in the steering wheel32. With its assistance, the operation, for example, of a hands-free apparatus or the control of a cruise control system can take place. A third push switch1is arranged in the door33of the driver's side. With this push switch1, the opening of the door33, for example, can be initiated, wherein a note can be displayed as necessary on a display of the push switch1if the adjacent traffic presents a hazardous situation.

LIST OF REFERENCE NUMERALS

The term “exemplary” used throughout the specification means “serving as an example, instance, or exemplification” and does not mean “preferred” or “having advantages” over other embodiments.