Patent Publication Number: US-2022216019-A1

Title: Rotary switch assembly, in particular of a steering wheel column integrated module of an automotive vehicle

Description:
The present invention relates to a rotary switch assembly, in particular of a steering wheel column integrated module of an automotive vehicle, comprising a support member, a control ring held rotationally by said support member, a slider disposed slidably along the axis of rotation of said control ring and cooperating with an activating member to generate electrical signals, wherein angular displacement of said control ring is converted into axial displacement of said slider. 
     BACKGROUND OF THE INVENTION 
     Rotary switches of this kind are frequently employed in steering wheel column integrated modules (CIM) in an automotive industry for controlling various components and subsystems of a vehicle including lights, windscreen wipers and washer, cruise control, audio system, etc. They usually form compact, preassembled units that at the vehicle assembly line are mechanically fixed to the steering wheel column and electrically connected to the vehicle wiring. Commonly the activating functionality is implemented using force-sensing resistive foils, conductive contact switches, electric signal devices of a capacitive nature, light gates, magnet and hall sensor, etc. 
     It is frequently desirable to provide a user, rotating the control element, with a haptic response, so s/he would know if a desired predefined effect of the component controlled by the switch has indeed been effected, with desired efficiency and without any other response of the system, such as control light being activated, etc. It is known to implement the haptic functionality by means of spring plungers acting on a curved cams. 
     Patent publication DE19939090 discloses a CIM having a rod attached near the steering column, and a holder fixed near the front end of the rod which has a bored elongated hole. An oblique hole is bored in a cam member coupled with a control element rotatably held by the holder. As an overlapped portion between the elongated hole and the oblique hole varies, an actuating portion of a receiver is moved correspondingly along the elongate holed changing the resistance value of a sliding type variable resistor. It is thus possible to carry out on/off control, speed control and so on of the vehicle-mounted electric components, e.g., front wipers. 
     Publications JP2008004359, JP2007273155 and EP1702796 disclose similar CIMs in which oblique cams are employed in order to convert rotational movement of a control element into a sliding movement of an actuating portion. 
     It has been the object of the present invention to provide a rotary switch that would provide recognition of direction of rotation, as well as discrete change of the parameter controlled by the switch assembly with fittingly perceivable haptic response indicating if such a change has been effected. It has been the further object of the present invention to provide a rotary switch with no angular limits of rotations, that would be compact, cost efficient and simple to manufacture and assembly in particular as a subcomponent of a steering wheel column integrated module. 
     SUMMARY OF THE INVENTION 
     The invention provides a rotary switch assembly of the kind mentioned in the outset, that is characterised in that said slider is provided with means for restoring the slider equilibrium position along said axis of rotation, said control ring is provided with a number of substantially equiangularly disposed radial protrusions, said slider is provided with a radial protrusion that extends in an area of a circumference defined by said radial protrusions of said control ring, in the slider equilibrium position remains between two adjoining radial protrusions of said control ring, and cooperates with said radial protrusions of said control ring, wherein said radial protrusion of said slider and/or said radial protrusions of said control ring has/have a form of a cam having two angularly external surfaces slanted at the same orientation with respect to the plane containing said axis of rotation. 
     Thanks to that, the slider displacement direction corresponds to the direction of rotation of the control ring. Furthermore displacement range of the slider is limited, which contributes to a compact construction of the rotary switch assembly. 
     Preferably the angular width of projection of said protrusion of said slider on the plane perpendicular to said axis of rotation is lower than the angular width between the adjoining protrusions of said control ring. 
     Thanks to that the slider returns to its equilibrium position after a radial protrusion of the control ring that pushed the radial protrusion of the slider has moved to the other side of the latter. 
     Preferably the rotary switch assembly comprises at least one spring plunger disposed substantially parallelly to said axis of rotation and cooperating with an annular haptic surface of said control ring that varies equiangularly along said axis of rotation. 
     The annular haptic surface reduces a so called free play haptic effect between loose elements and enables to predefine a required haptic response. 
     The term “spring plunger” as used in the context of the present invention denotes any element or assembly capable of exerting an axial force along the line of its disposition in order to extend its length, even if no helical spring is used to this end. 
     In such a case, said haptic surface preferably provided with a number of axial projections and recessions in between them, wherein said projections axially coincide with said radial protrusions of said control ring, and preferably varies substantially triangularly along said axis of rotation. 
     Thanks to that the haptic response of the control ring is better correlated with displacements of the slider. 
     Preferably said external surfaces of said cam are slanted at the same angle that amounts about 45°. 
     Thanks to that the ratio of the slider displacements in dependence of rotations of the control ring is the same for both directions of rotations. 
     Preferably said means for restoring the slider equilibrium position along said axis of rotation comprise at least one spring plunger disposed substantially perpendicularly to said axis of rotation and cooperating with a surface provided with an equilibrium recession in which the elastic energy of the plunger is locally minimal. 
     This is a particularly simple and compact construction for maintaining the slider equilibrium position. Alternatively a spring or other elastic element attached to the slider could be employed. 
     Preferably said slider is guided by said support. 
     This facilitates delivering the switch assembly as a compact, preassembled unit. 
     Preferably the rotary switch assembly according to the present invention has a form of a column integrated module of an automotive vehicle. 
     CIMs enable a particularly convenient access to the rotary switch assembly. 
     Preferably said control ring is available for a user at the entire circumference thereof and has no reference direction. 
     Therefore the control ring always remains in an equilibrium rest position and user may freely rotate it from any angular direction and with no angular end stops. 
     Preferably said radial protrusions of said control ring are disposed radially inwardly and said radial protrusion of said slider is disposed radially outwardly. 
     This contributes to a compact construction of the rotary switch assembly. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The invention shall be described and explained below in connection with the attached drawings in which: 
         FIG. 1  is a schematic perspective, exploded view of an embodiment of a rotary switch assembly according to the present invention in a steering wheel column integrated module; 
         FIG. 2  is a schematic perspective, exploded view of an embodiment of a rotary switch assembly; 
         FIG. 3  illustrates an embodiment of an electrical connection of the rotary switch assembly; 
         FIG. 4  is a schematic perspective, exploded view of the assembled rotary switch shown in  FIG. 2 ; 
         FIG. 4 a    is an enlarged fragment of  FIG. 4  showing the cam in relation to the annular haptic surface; 
         FIG. 4 b    is a cross-sectional view of the cam in relation to the cylindrical radial protrusions; 
         FIG. 5  is a schematic cross-sectional of another embodiment of the rotary switch assembly according to the present invention; 
         FIG. 5 a    is an enlarged fragment of  FIG. 5  showing adjoining actuators with a rhomboidal cross-section in detail, one on either side of a cylindrical rail protrusion; 
         FIGS. 6 a , 6 b , 6 c , and 6 d    are schematic cross-sectional views illustrating functionality of the rotary switch assembly according to the present invention during right-hand rotation; and 
         FIGS. 7 a , 7 b , 7 c , and 7 d    are schematic cross-sectional views illustrating functionality of the rotary switch assembly according to the present invention during left-hand rotation. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     As shown in  FIG. 1 , the embodiment of a rotary switch assembly  1   a  comprises a support member  2 , an activating member  3 , a control ring  4  and a slider  5 . In this embodiment the control ring  4  is disposed rotationally within the support member  2 , the activating member  3  has a form of a printed circuit board and is disposed within the support member  2 , the slider  5  is disposed slidably, along the axis of rotation of the control ring  4 , within the support member  2  and cooperates with the control ring  4  and the activating member  3 , as shall be described below, to generate electrical signals. The whole switch assembly  1   a  is snap-locked to a lever  6  and at the end snap-locked with a cap  7 , by means of snap-locking latches  26  and  71 , forming a compact, preassembled steering wheel column integrated module of an automotive vehicle (not shown) that may be at the vehicle assembly line mechanically fixed to the steering wheel column and electrically connected to the vehicle wiring not shown in the drawing in a manner well known to those skilled in the art. Turning the control ring  4  may be employed for controlling various components and subsystems of the vehicle such as windscreen wipers frequency, cruise control speed, audio system etc. On the other hand the inclinations of the lever  6  may be employed for turning the wipers or cruise control on and off, etc. 
     As shown in  FIG. 2  and  FIGS. 4, 4   a  &amp;  4   b , the control ring  4  is available to be turned by a user at the entire circumference thereof and may freely rotate over the support member  2  with no particular reference direction or resting position. The control ring  4  has an annular haptic surface  41  that varies triangularly along the axial direction with twelve axial projections  411  and twelve recessions  412  in between them. Haptic surface  41  cooperates with two spring plungers  21  disposed coplanarly with the axis A of rotation of the control ring  4  in two sockets  22  of the support member  2 . Each spring plunger  21  comprises an engaging cap  211  encompassing a spring  212  with a spherical tip pressing against the haptic surface  41 . Such a construction provides a perceivable haptic response to a user rotating the control ring  4  which will tend to maintain its angular positions in which the engaging caps  211  of the spring plungers  21  remain in the recessions  412 , ensuring locally minimum elastic energy of the springs  212 . Therefore for N projections  411 , user must rotate the control ring  4  against the forces of the springs  212  slightly more than by  7   t /N in order to move the engaging caps  211  over the projections  411  and make them contribute to further rotation of the control ring  4  unless the engaging caps  211  settle in the adjoining recessions  412 . In the presented embodiment of twelve projections  411 , rotation of more than 15° is required and the corresponding angular step of the control ring  4  amounts 30°. Obviously in other embodiments of the haptic surface  41  the number of projections  411  and recessions  412  could be different and the shape of the haptic surface  41  could be obviously sinusoidal, oval or even asymmetrical w/r/t direction of rotation of the ring, providing that the pattern of the haptic surface  41  is substantially equiangular over the perimeter of the control ring  4 . Also in other embodiments of the invention a different number of plungers  21  might be employed to improve the haptic response and said control ring  4  might be activated by an additional gearing wheel accessible to the user. 
     As shown in  FIG. 2  and  FIGS. 4, 4   a  &amp;  4   b , the activating member  3  is axially inserted and stabilized in slots  23  of the support member  2 . Slider  5  is provided with two guiding rails  55  disposed slidably in slots  24  of the support member  2  located above the slots  23  of the activating member  3 . The support member  2  is further provided with two axial self-returning surfaces  25 , each having a triangular cross-section in a plane of the slots  24  with an equilibrium recession  251 . Each surface  25  cooperates with a spring plunger  51  disposed coplanarly with the slots  24  in a socket  53  of the slider  5 , substantially perpendicularly to the axis A. Each spring plunger  51  comprises an engaging cap  511  encompassing a spring  512  (cf.  FIG. 1 ) with a spherical tip pressing against the self-returning surface  25 , in order to maintain the equilibrium position of the slider  5  w/r/t the activating member  3 . With such a shaping of the surfaces  25 , the slider  5  will tend to maintain its equilibrium position in which the engaging caps  511  of the spring plungers  51  remain in the equilibrium recessions  251 , ensuring locally minimum elastic energy of the springs  512 . 
     As shown in  FIG. 2  and  FIGS. 4, 4   a  &amp;  4   b , the control ring  4  is provided at its internal surface with twelve radial protrusions  42   a  axially coinciding with projections  411  of the haptic surface  41 . The protrusions have substantially cylindrical cross-sections and are provided with circumferential rails  421  at their ends. The slider  5  in turn is provided with a radial protrusion  52   a  that extends between the two adjoining radial protrusions  42   a  of the control ring  4  in an area of a circumference defined by the radial protrusions  42   a . In this embodiment the radial protrusion  52   a  of the slider  5  has a form of a cam  8  and the radial protrusions  42   a  of the control ring  4  have a form of actuators. The cam  8  has a substantially rhomboidal cross-section, in a plane which is parallel to the axis A and tangent to a circumference defined by the radial protrusions  42   a  (i.e. the plane of cross-sections shown in  FIGS. 4 b -7 d   ), with rounded edges and two external surfaces  81 ,  82  at the angular direction slanted with respect to the axial direction respectively and at angles α 1  and α 2  having the same orientation. In this embodiment, angles α 1  and α 2  are substantially the same and amount about 45°. In other embodiments the cam  8  could have an obtuse trapezoid shape with surfaces  81  and  82  slanted at different angles α 1  and α 2  or even curved w/r/t the axial direction. 
     The angular width w of projection of the cam  8  on the plane perpendicular to the axis of rotation of the control ring  4  is slightly lower than the angular width W between the adjoining actuators. 
     As shown in  FIG. 3  in this embodiment the slider has a connecting blade  54  that remains electrically connected with a main conductive path  31  of the activating member  3  regardless of the position of the slider  5 . Left turn conductive path  32 , neutral conductive path  33 , and right turn conductive path  34  adjoin the main conductive path  31  along the direction of the slide of the slider  5 , so that in the equilibrium position of the slider  5  the main conductive path  31  and the neutral conductive path  33  remain electrically connected by the connecting blade  54 . While the slider  5  deviates from its equilibrium position in either direction, first the connection between paths  31  and  33  breaks and subsequently, after a certain displacement threshold, determined mainly by the shape of the blade  54  and separation between the neutral conductive path  33  and the left turn  32  or right turn  34  conductive path, a new connection between one of these paths  32  or  34  and the main conductive path  31  is established by the connecting blade  54  of the slider  5 . In other embodiments of the invention the electrical contact provided by the connecting blade  54  could obviously be replaced by light gate, magnet and hall sensor, etc. In any case rotation of the control element  4  in a particular direction, even if incomplete (cf.  FIG. 6 b   ,  FIG. 7 b   ), may be used to encode a predefined input transmitted to a given vehicle component controlled by the switch  1 . 
     The functionality of the switch  1   a  is illustrated in  FIGS. 6 and 7 . As shown in  FIG. 6 a    the protrusion  52   a  (the cam  8 ) of the slider  5  rests in an equilibrium position between the protrusion  42   a   (1)  and the protrusion  42   a   (2)  of the control ring  4 . As shown in  FIG. 6 b   , the protrusion  42   a   (2)  (lower w/r/t the plane of the drawing) of the control ring  4  rotated by a user right (upward) acts on the right turn surface  81  of the cam  8  of the slider  5  forcing the slider to move right. This intermediate position may be detected e.g. by a broken connection between the main conductive path  31  and the neutral conductive path  33  (cf.  FIG. 3 ). Yet in this position the control ring  4 , if released, will return to its equilibrium position shown in  FIG. 6 a   . Only after crossing a threshold angular position shown in  FIG. 6 c    will it assume a subsequent equilibrium position between the protrusions  42   a   (2)  and  42   a   (3)  shown in  FIG. 6 d   . Achieving this threshold position may obviously be detected e.g. by establishing connection between the main conductive path  31  and the right turn conductive path  34 . Left-hand rotation of the switch assembly  1   a  shown in  FIG. 7  is analogous. 
       FIG. 5  and  FIG. 5 b    illustrate another embodiment of the rotary switch assembly  1   b  in which radial protrusions  42   b  of the control ring  4  have forms of cams  8 , while the radial protrusion  52   b  of the slider  5  is substantially cylindrical. As in the previous embodiment, angles α 1  and α 2  define the ratio between displacement of the radial protrusions  42   b  of the control ring  4  and displacement of the radial protrusion  52   b  of the slider  5  that a given radial protrusions  42   b  acts upon with its right or left turn angularly external surface  81  or  82 . In other embodiments both radial protrusions  42  of the control ring  4  and radial protrusion  52  of the slider  5  could have a form of cams. 
     The above embodiments of the present invention are therefore merely exemplary. The figures are not necessarily to scale and some features may be exaggerated or minimized. These and other factors however should not be considered as limiting the spirit of the invention, the intended scope of protection of which is indicated in appended claims. 
     LIST OF REFERENCE NUMERALS 
     
         
           1 . rotary switch assembly ( 1   a ,  1   b ) 
           2 . support member
         21 . spring plunger
             211 . engaging cap     212 . spring         22 . socket     23 . slot (of the activating member)     24 . slot (of the slider)     25 . self-returning surface
             251 . equilibrium recession         26 . snap-locking latch     
           3 . activating member
         31 . main conductive path     32 . left turn conductive path     33 . neutral conductive path     34 . right turn conductive path     
           4 . control ring
         41 . annular haptic surface
             411 . axial projection     412 . axial recession         42 . radial protrusion ( 42   a ,  42   b )
             421 . circumferential rail         
           5 . slider
         51 . spring plunger
             511 . engaging cap     512 . spring         52 . radial protrusion ( 52   a ,  52   b )     53 . socket     54 . connecting blade     55 . guiding rail     
           6 . lever 
           7 . cap
         71 . snap-locking latch     
           8  cam
         81 . right turn angularly external surface     82 . left turn angularly external surface