Abstract:
Disclosed is a rotating actuator with a variable latching profile, the rotating actuator having a housing, a rotary knob and a rotary shaft connected in a rotationally fixed manner to the rotary knob, and also at least two latching contours connected in a rotationally fixed manner to the rotary shaft, one support per latching contour, on which support at least one latching element is arranged, the latching element engaging in the latching contour assigned to the support, and which support is mounted rotatably about the rotary shaft, and at least one locking device per support, by means of which the support can be locked relative to the housing.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to co-pending German Patent Application No. DE 10 2007 032 395.8, filed Jul. 10, 2007 which is hereby expressly incorporated by reference in its entirety as part of the present disclosure. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a rotating actuator with a variable latching behavior according to the preamble of the patent claim  1 . 
     BRIEF DESCRIPTION OF RELATED ART 
     In the case of rotating actuators, in particular in motor vehicles, it is desirable to provide the operator with a haptic feedback concerning the rotation of the rotating actuator by a certain amount, in order to indicate the completion of an operating step, for example. For this purpose, rotating actuators comprising a latching behavior are known in which a latching element latches into a latching contour. This, however, is disadvantageous in that such a rotating actuator has an invariable latching behavior and is thus suitable only in a limited extent for operating a plurality of functions, for example, of an on-board computer. 
     An electronically controlled fluid rotary knob as a haptic control element is known from the published patent application DE 100 29 191 A1, wherein the rotary knob of the rotating actuator moves in a magnetorheological fluid, the viscosity of which can be controlled by means of a magnetic field. By controlling the magnetic field it is possible to generate different latching behaviors. Such a rotating actuator has a complex structure, is expensive to manufacture and requires a complicated control system. 
     BRIEF SUMMARY OF THE INVENTION 
     It is the object of the present invention to provide a rotating actuator with a variable latching behavior that does not exhibit the drawbacks of the prior art. 
     The object is achieved by a rotating actuator in accordance with patent claims  1  and  2 . Advantageous embodiments are apparent from the dependent patent claims. 
     A rotating actuator with a variable latching behavior according to patent claim  1  comprises a housing, a rotary knob, a rotary shaft non-rotatably connected to the rotary knob and at least two latching contours non-rotatably connected to the rotary shaft. Furthermore, the rotating actuator comprises one support per latching contour, whereon at least one latching element is disposed which latches into the latching contour associated with the support, and which is mounted so as to be rotatable about the rotary shaft. The number of the supports matches the number of the latching contours. In addition, the rotating actuator comprises at least one locking device per support, by means of which the support can be locked relative to the housing. 
     In an alternative embodiment according to patent claim  2 , the rotating actuator comprises a housing, a rotary knob, a rotary shaft non-rotatably connected to the rotary knob and at least two latching elements non-rotatably connected to the rotary shaft. Upon rotation of the rotary knob, the latching elements thus move together with the rotary shaft. Furthermore, the rotating actuator has one support per latching element, with a latching contour being disposed on the support, into which the latching element associated with the support latches, and wherein the support is mounted so as to be rotatable about the rotary shaft. In addition, the rotating actuator comprises at least one locking device per support, by means of which the support can be locked relative to the housing. The number of the supports preferably matches the number of the latching elements. Optionally, the number of the latching elements is greater than the number of the supports if two latching elements latch into the latching contour of the same support. 
     The latching elements establish a connection in a positive fit between the latching contours, and thus the rotary knob, and the supports. If all the locking devices are deactivated, that is, the supports are not locked, then a rotation of the rotary knob causes a rotation of the supports. The supports rotate with the same angular speed as the rotary knob. 
     If the locking device is activated, then the associated support is fixed relative to the housing of the rotating actuator. A rotation of the rotary knob is opposed by a force generated in a known manner by the latching element and the latching contour. If the operator overcomes this force, the rotary knob and the rotary shaft rotate relative to the locked support. The latching element moves over the latching contour and the operator receives a haptic feedback concerning the rotation of the rotary knob in the form of a latching stop. The behavior of the latching stop over the angle of rotation of the rotary knob in this case substantially depends on the design of the latching contour. 
     If the locking device of the other support is activated, then this other support is fixed relative to the housing of the rotating actuator. When the rotary knob is rotated, the result is a latching behavior which substantially depends on the latching contour into which the latching element disposed on the fixed other support latches. Thus, the latching behavior can be varied by selecting the locked support. For this purpose, the latching contour and/or the latching elements preferably are configured in different ways. Optionally, several supports can be locked simultaneously, so that the latching behavior is a result of the superposition of the individual latching stops. 
     The latching contour is a successive arrangement of depressions and elevations, so that the result is, for example, a saw-tooth profile or an undulating profile. Preferably, the latching contour forms a closed circle. Depending on the configuration of the rotating actuator, the latching contour is located on the inside or the outside of the support. The number of latching positions per complete revolution of the rotary knob depends upon the number of depressions of the latching contour. The force for overcoming a latching stop is dependent, among other things, upon the height of the elevations relative to the depressions. The force curve of the latching stop depends on the shape of the flanks of the latching profile. The latching element preferably is a spring-mounted ball or a latch spring. 
     The locking device is preferably disposed stationary in the housing. It has, for example, a locking bar which is introduced into a recession of the support associated with the locking device or withdrawn from the recession by means of, for example, a feed mechanism. In another embodiment, the locking device comprises a magnetic ball latching device as it is described below. 
     A magnetic ball latching device comprises at least one permanent magnet, an electromagnet on a ferromagnetic core, and a ball which can be brought into engagement with a latching profile in a support. In this case, the permanent magnet is movably disposed in the device and can be moved between at least two end positions. 
     The permanent magnet is disposed between the open end of the ferromagnetic core and the ball. The ball consists of a magnetic or magnetizable material so that a force is exerted on the ball by a magnetic field. In each of its end positions, the permanent magnet is located in the area of the end of a leg of the ferromagnetic core. The magnetic field of the permanent magnet extends into the legs of the ferromagnetic core and thus retains the permanent magnet in its position. 
     A change of position of the permanent magnet is achieved by applying current to the electromagnet, so that a magnetic field forms in the ferromagnetic core as a consequence. The direction of the current through the electromagnet, and thus the direction of the magnetic field in the ferromagnetic core, is selected such that the magnetic pole corresponding to the pole of the permanent magnet facing the ferromagnetic core forms at that leg in the area of which the permanent magnet is located. This causes a repulsion of the permanent magnet from its current position into the other end position. Preferably, the movable permanent magnet is configured such that the permanent magnet is prevented from tipping over. In this context, tipping over means that the permanent magnet rotates in such a way that the other magnetic pole faces the ferromagnetic core. 
     The ball located in the area of the magnetic field of the permanent magnet follows the movement of the permanent magnet and can thus also be moved, for example, between two end positions. In one end position, the ball is in engagement with the latching profile in the support and thus blocks the movement of the support at least in one direction. In another end position, the ball is not in engagement with the latching profile. Due to the relatively small distance between the ball and the permanent magnet, a comparatively weak permanent magnet already leads to a strong magnetic force on the ball, and thus to a high resistance to vibration. 
     Preferably, the ferromagnetic core, which for example consists of iron, is substantially formed to be U-shaped. However, any other, in particular asymmetric, shape of the ferromagnetic core is possible without limiting the locking functionality. 
     The electromagnet disposed on the ferromagnetic core and the movable permanent magnet form a mechanical bistable flip-flop, with the ball following the position of the permanent magnet. Even if the ball is jammed in the latching profile, the permanent magnet is movable. If the ball is not jammed anymore at a later point in time, it follows the permanent magnet and withdraws from the engagement with the latching profile. 
    
    
     
       BRIEF DESCRIPTION DRAWINGS 
       The present invention is now to be explained in more detail with reference to four exemplary embodiments. In the drawings: 
         FIG. 1  shows a first embodiment of the rotating actuator according to the invention comprising three latching contours, 
         FIG. 2  shows a second embodiment of the rotating actuator according to the invention comprising two latching contours, 
         FIG. 3  shows a third embodiment of the rotating actuator according to the invention comprising two latching contours, 
         FIG. 4  shows a fourth embodiment of the rotating actuator according to the invention comprising three latching contours, 
         FIG. 5  shows a detailed view of a magnetic ball latching device, and 
         FIG. 6  shows a detailed view of a magnetic ball latching device in engagement with a latching profile. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIGS. 1 to 4  show schematic sectional views of different embodiments of the rotating actuator  1  according to the invention comprising a rotary knob  2  and a rotary shaft  3  non-rotatably connected with the rotary knob. For providing a better overview, the housing was omitted in  FIGS. 1 ,  3  and  4 . Recurring identical elements are provided with identical reference numerals. 
     The rotating actuator  1  according to  FIG. 1  comprises three latching contours  5 ,  11  and  17 , which are respectively incorporated in one of the latching discs  4 ,  10  and  16 . The latching discs  4 ,  10  and  16  are non-rotatably connected with the rotary shaft  3  or formed integrally with the rotary shaft  3 . Three disc-like supports  6 ,  12  and  18  are mounted so as to be rotatable about the rotary shaft  3 . A ball  7  latching into the latching contour  5  of the latching disc  4  is mounted on the support  6  by means of a spring  8 . A ball  13  latching into the latching contour  11  of the latching disc  10  is mounted on the support  12  by means of a spring  14 . A ball  19  latching into the latching contour  17  of the latching disc  16  is mounted on the support  18  by means of a spring  20 . 
     Three magnetic ball latching devices  9 ,  15  and  21 , which respectively include a movable ball, are disposed stationary in the housing of the rotating actuator  1 . As will be described with reference to  FIGS. 5 and 6 , the balls can be brought into engagement with the latching profiles in the outer circumference of the supports  6 ,  12  and  18 . If a ball latches into a latching profile, the corresponding support is locked. This means that the support is incapable of rotating in the housing of the rotating actuator  1 . 
     If none of the ball latching devices  9 ,  15  and  21  is activated, then all three supports  6 ,  12  and  18  can be rotated about the rotary shaft  3 . If the rotary knob  2  is rotated, the balls  7 ,  13  and  19  exert forces on the supports  6 ,  12  and  18 , so that they rotate at the same angular speed as the rotary knob  2 . 
     In  FIG. 1 , the position of the balls of the ball latching devices is indicated by circles. In the present case, the latching device  15  is activated, that is, the ball of the latching device  15  is in engagement with the latching profile on the circumference of the support  12 . The rotation of the support  12  is thus disabled and the ball  13  runs through the latching contour  11  in the latching disc  10  upon rotation of the rotary knob  2 . For overcoming a latching stop, a flank of the latching contour  11  urges the ball  13  against the force of the spring  14  in the direction of the support  12 . This can be haptically perceived by the operator of the rotating actuator  1  as a latching stop. 
     The latching contours  5 ,  11  and  17  are configured in different ways, as is indicated in  FIG. 1 . Due to the different configuration of the latching contours, the force curve changes when a latching stop is being overcome, and/or the number of latching stops per rotation of the rotary knob  2 . By selecting which ball latching device is activated and thus, which of the supports is locked, the latching behavior of the rotating actuator  1 , that is, its haptic characteristic curve, can be varied. Depending on the desired latching behavior, one or more of the supports is locked. 
     In a second embodiment according to  FIG. 2 , the rotary shaft  3  is rotatably mounted in a housing  22  by means of ball bearings  23 . The rotary shaft  3  comprises two cylindrical latching discs  24  and  31  spaced in the direction of the axis of the rotary shaft  3  and formed concentrically with the rotary shaft  3 . Latching contours  25  and  32 , respectively, which are configured differently, are incorporated in the end faces of the latching discs  24  and  31  that face each other. 
     Between the latching discs  24  and  31 , the supports  26  and  33  are disposed so as to be rotatable about the rotary axis  3 . The support  26  retains a ball  28  which is movable against the force of a spring  29  in the direction of the axis of the rotary shaft  3 . An annular saw-tooth latching profile  27  is disposed on the outer edge of the disc-like support  26 . The support  33  retains a ball  35  which is movable against the force of a spring  36  in the direction of the axis of the rotary shaft  3 . An annular saw-tooth latching profile  34  is disposed on the outer edge of the disc-like support  33 . 
     A ball of a ball latching device  30  can be introduced into the latching profile  27 , a ball of a ball latching device  37  can be introduced into the latching profile  34 . If a ball latching device is activated, that is, if a ball has been introduced into a latching profile, then the associated support is locked, that is, its rotation relative to the housing  22  is blocked. 
     In analogy to the first exemplary embodiment, the rotary knob  2  can be freely rotated when the ball latching devices  30  and  37  are deactivated. For example, if the ball latching device  30  is activated, its ball latches into the latching profile  27  and locks the support  26 . If the rotary knob  2  is now rotated, the ball  28  moves over the latching contour  25  and is displaced against the force of the spring  29  in the process. The operator of the rotating actuator  1  perceives this haptically as a latching behavior. A latching behavior results in an analogous manner if the ball latching device  37  is activated and if the ball  35  moves over the latching contour  32 . If the latching contours  25  and  32  are configured differently, then different latching behaviors result. If both ball latching devices  30  and  37  are activated, the result is a superposed latching behavior. 
       FIG. 3  shows another exemplary embodiment in which the rotating actuator  1  comprises a cup-shaped rotary knob  2 . Two supports  38  and  43  are also configured cup-shaped and are disposed concentrically relative to each other and to the rotary knob  2  so as to be rotatable about the rotary shaft  3 . The support  38  is mounted in the rotary knob  2  by means of a ball bearing  42 , the support  43  is mounted in the support  38  by means of a ball bearing  47 . A circular retaining disc  49 , which extends perpendicularly to the rotary shaft  3 , and through the center of which the rotary shaft  3  extends, retains the support  43 , and thus also the support  38 , by means of a ball bearing  48 . 
     Two latching balls  40  and  45  are non-rotatably connected with the rotary shaft  3 , they thus rotate with the same angular speed as the rotary knob  2 . The latching balls  40  and  45  are mounted by means of springs  41  and  46 , respectively, so that, relative to the rotary shaft  3 , they are movable in the radial direction. The ball  40  latches into a latching contour  39  in the support  38 , the ball  45  latches into a latching contour  44  in the support  43 . The latching contours  39  and  44  extend along the circumference of circular recesses in the bottom surfaces of the supports  38  and  43 , respectively. 
     A latching profile  53 , which cooperates with a ball latching device  52 , is incorporated in the annular edge of the support  38 . A latching profile  51 , which cooperates with a ball latching device  50 , is incorporated in the annular edge of the support  43 . Just as in the preceding exemplary embodiments, the supports  38  and  43  are freely rotatable about the rotary shaft  3  when the ball latching devices  50  and  52  are deactivated. If the rotary knob  2  is rotated, the balls  40  and  45  entrain the supports  38  and  43 , respectively. 
     If a ball latching device  50  or  52  is activated, a ball latches into the associated latching profile  51  or  53 , respectively, whereby the support  43  or  38 , respectively, is locked. If the ball latching device  50  is activated, then the ball  45  moves over the latching contour  44  when the rotary knob  2  is rotated and generates a latching behavior which can be perceived as a rotary haptic feedback by the operator of the rotating actuator  1 . If the ball latching device  52  is activated, then the ball  40  moves over the latching contour  39  when the rotary knob  2  is rotated and generates a latching behavior which preferably deviates from the latching behavior generated by the ball  45  in conjunction with the latching contour  44 . 
     Another embodiment of the rotating actuator  1  according to  FIG. 4  differs from the rotating actuator according to  FIG. 3  in that three cup-shaped supports  54 ,  55  and  56  are disposed concentrically relative to one another and to the rotary knob  2 . The supports  54 ,  55  and  56  are rotatable about the rotary axis  3  and can be locked separately by means of ball latching devices that are not shown. An unlocked support is rotated by an associated latching ball when the rotary knob  2  is rotated, in the case of a locked support, the latching ball moves over a latching contour on or in the support  54 ,  55  or  56  and generates a corresponding latching behavior. The rotating actuators  1  according to the  FIGS. 3 and 4  are particularly compact. 
       FIGS. 5 and 6  show, by way of example, the ball latching device  50  from  FIG. 3 . The ball latching device  50  substantially consists of an electromagnet  58  on a ferromagnetic, U-shaped core  57 , a permanent magnet  59  and a magnetizable ball  60 . The permanent magnet  59  is mounted so as to be displaceable between two end positions, and disposed and guided in such a way that one of its magnetic poles permanently points in the direction of the ferromagnetic core  57 . In each of its end positions, the permanent magnet is located in the area of one of the legs at the open end of the ferromagnetic core  57 . Because of the magnetic force, the magnetizable ball  60  follows the movement of the permanent magnet  59 . In  FIGS. 5 and 6 , the magnetic north pole is represented in a dotted way and the magnetic south pole in a hatched way. 
     In the state shown in  FIG. 5 , the ball latching device  50  is deactivated. The permanent magnet  59  is in its first end position and the ball  60  is not in engagement with the latching profile  51  of the support  43 . 
     If the ball latching device  50  is activated, the electromagnet  58  reverses the magnetic field in the ferromagnetic core  57 . A magnetic force acts on the permanent magnet  59  which moves it into its second end position shown in  FIG. 6 . The ball  60  follows the movement of the permanent magnet  59  and thus comes into engagement with the latching profile  51  of the support  50 . The support  43  is now locked. 
     The magnetic ball latching devices  9 ,  15 ,  21 ,  30 ,  37  and  52  substantially have the same structure as the magnetic ball latching device  50 .