Abstract:
A device for detecting an actuation angle of an element rotatable or pivotable about a shaft of the mentioned type. The device includes a sensor unit configured to emit an electrical signal depending on an angle of rotation and including an annular permanent magnet non-movably connected to the rotatable or pivotable element. The sensor includes a stationary Hall sensor array having two or more Hall sensors disposed at an angular distance about the annular permanent magnet, wherein an individual Hall sensor located in a linear zone defined by the movement of the rotatable or pivotable element is selected by a microcontroller according to a current position of the rotatable or pivotable element.

Description:
RELATED APPLICATION AND CLAIM OF PRIORITY 
       [0001]    This application claims the priority benefit of P.C.T. Application no. PCT/EP2008/003853 filed May 14, 2008, which is hereby incorporated by reference in its entirety; which claims priority to German Patent Application No. 10 2007 024 249.4-42 filed May 18, 2007. 
         [0002]    Not Applicable 
     
    
     BACKGROUND 
       [0003]    The present disclosure relates to a device for detecting an actuation angle of more than 90° of an element rotatable or pivotable about a shaft. 
         [0004]    As shown in German Patent No. 101 33 492 A 1, a device for detecting an actuation angle of an element rotatable or pivotable about a shaft in the form of a foot pedal is known. In this device, one or more permanent magnets are associated with two Hall sensors of a Hall sensor array. The Hall sensor array functions such that the pivoting movement of a foot pedal in the one direction is identified by a first Hall sensor as a positive angular movement and 
         [0005]    In this known device, thus, only a limited angular range of ±&lt;90° can be detected and evaluated. For certain applications this is not sufficient. 
       SUMMARY 
       [0006]    Before the present methods are described, it is to be understood that this invention is not limited to the particular systems, methodologies or protocols described, as these may vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to limit the scope of the present disclosure which will be limited only by the appended claims. 
         [0007]    It must be noted that as used herein and in the appended claims, the singular forms “a,” “an,” and “the” include plural reference unless the context clearly dictates otherwise. Thus, for example, reference to a “coil” is a reference to one or more coils and equivalents thereof known to those skilled in the art, and so forth. Unless defined otherwise, all technical and scientific terms used herein have the same meanings as commonly understood by one of ordinary skill in the art. As used herein, the term “comprising” means “including, but not limited to.” 
         [0008]    It is an object of the present invention to provide a device for detecting an actuation angle of an element rotatable or pivotable about a shaft of the type as described in the 
         [0009]    In order to solve this object, in a device for detecting an actuation angle of an element rotatable or pivotable about a shaft of the mentioned type. The device includes a sensor unit configured to emit an electrical signal depending on an angle of rotation and including an annular permanent magnet non-movably connected to the rotatable or pivotable element. The sensor includes a stationary Hall sensor array having two or more Hall sensors disposed at an angular distance about the annular permanent magnet, wherein an individual Hall sensor located in a linear zone defined by the movement of the rotatable or pivotable element is selected by a microcontroller according to a current position of the rotatable or pivotable element. 
         [0010]    In using this device, it is possible to evaluate an angle of more than 180° as several sensors are distributed about the circumference of the annular permanent magnet. Therein, the signal of the Hall sensor located in the most advantageous zone of as defined by the movement of the rotatable or pintable element is respectively used, wherein the microcontroller or the electronic circuit thereof determines which one of the Hall sensors in a certain angular range is selected and classified as active. By the arrangement of three instead of two Hall sensors, moreover, it is possible to evaluate a complete rotation of 360° of the rotatable element. Moreover, a further sensor may be disposed if the evaluation is to be redundant. 
         [0011]    Further details of the invention are apparent from the following description, in which the invention is described and explained in more detail by way of the embodiments illustrated in the figures. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    Aspects, features, benefits and advantages of the present invention will be apparent with regard to the following description and accompanying drawings, of which: 
           [0013]      FIG. 1  illustrates an exemplary device having two sensors for detecting an actuation angle of more than 180° according to an embodiment; 
           [0014]      FIG. 2  illustrates a sectional view of the device of  FIG. 1  along the line II-II according to an embodiment; 
           [0015]      FIG. 3  illustrates an enlarged cutout representation according to the circle III of  FIG. 1  according to an embodiment; 
           [0016]      FIG. 4  illustrates an enlarged cutout representation according to the circle IV of  FIG. 2 , and 
           [0017]      FIG. 5  illustrates an exemplary diagram of an analog-digital converted signal voltage of the two sensors according to an embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0018]    The exemplary device  10  illustrated in the  FIGS. 1-4  may serve as an armrest on tractors or as an output shaft for coupling agricultural machines to tractors. The device  10  may be configured to adjust and detect an actuation angle of more than 90°, or 180° and greater, in the same rotational direction of an input element  11  about a shaft  12 . The adjustment and detection of the actuation angle may be effected via a magnetic field sensor unit composed of a Hall sensor array  13  and an annular permanent magnet  14 , thereby driving or adjusting the component to be operated and adjustable in its actuation angle in a non-illustrated manner. While the unique annular permanent magnet  14  may be disposed on the wheel-shaped input element  11 , the Hall sensor array  13  may be retained on a sensor retainer  15  with respect to which the wheel-shaped input element  11  is rotatable concentrically by an angle of &gt;90° or of &gt;180° (in the illustrated embodiment of 210° to 220°) in the same direction. In one possible embodiment, the wheel shaped element  11  may be rotatable up to 360°. 
         [0019]    The inverted, approximately pot-shaped sensor retainer  15  may be integrally formed of plastic, or other similar material, having a bottom  16  and a circumferential jacket  17 . The bottom  16  of the sensor retainer  15  may be centrally penetrated by a hollow metallic shaft  18  and rotationally fixedly connected to the shaft  18 . A radial flange  19  of the hollow shaft  18  may be insert-molded with the bottom  16 . Thereby, exact positioning of the hollow shaft  18 , which is preferably made of steel, to the sensor retainer  15  may be achieved. 
         [0020]    In an exemplary embodiment, the jacket  17  of the sensor retainer  15  may have two recesses  22  disposed at an angular distance of slightly less than 90°, e.g., 80°, to each other and emanating from an axial lateral surface  21 : The axial lateral surface  21  may transition through a ring switch surface  23  into a lower-diameter through-bore  24  in the axial direction. A single Hall sensor  25  or  25 ′ of the Hall sensor array  13  may be individually inserted in these recesses  22  or chambers, electrical contact pins  26  of which may penetrate the through-bore  24  and protrude from the bottom  16  of the sensor retainer  15 . Each Hall sensor  25 ,  25 ′ may be supported in the recess  22  by one or more crimping ribs  27 ,  27 ′ at two mutually perpendicular lateral surfaces, between which the Hall sensor  25 ,  25 ′ may be retained. Thereby, the Hall sensor  25 ,  25 ′ may be restrained firmly into a corner of the chamber  22 . In an exemplary embodiment, a short side of the chamber  22  may have a single crimping rib  27 , while a long side extending perpendicularly thereto may have two spaced crimping ribs  27 ′. It is understood that the number of the crimping ribs  27 ,  27 ′ or the cross-section of the chamber  22  may be configured in another manner depending on the configuration of the chamber  22  and the number of Hall sensors  25 ,  25 ′ being used. 
         [0021]    At the bottom  16  of the sensor retainer  15 , a printed circuit board or board  29  may be located facing away from the chambers  22 , which is centrally disposed about an axial annular flange of the bottom  16 . The board  29  may be fixedly connected to the bottom  16 . The contact pins  26  of the Hall sensor  25 ,  25 ′ may be plugged through electrically conducting bores  31  of the board  29  and soldered. Thereby, the electrical connection of the Hall sensors  25 ,  25 ′ may be achieved through the board  29 . 
         [0022]    Although only two Hall sensors  25  and  25 ′ are disposed at an angular distance of slightly less than 90°, e.g., 80°, in an exemplary embodiment, it is understood that three or four Hall sensors  25  may be disposed or provided about the circumference of the lateral surface  21  in a corresponding plurality of chambers  22 . With two Hall sensors  25 ,  25 ′ according to an exemplary embodiment, an angular range of about 210° to 220° may be achieved. With three Hall sensors, an angular range of 360° may be achieved. A redundant evaluation of the actuation angle of 360° may be achieved by four of more Hall sensors  25 . 
         [0023]    The wheel-shaped input element  11  may have a bottom  36  and a handle  37  integrally made of plastic or other similar material. The handle  37  may be formed in the manner of a lateral surface tapering conically, curved from the bottom to the top, which is open for gripping around the sensor retainer  15  in a manner facing it. 
         [0024]    The bottom  36  may integrally have an inner sleeve  38  axially protruding to both sides of the bottom  36 , wherein the sleeve section  39  located within the handle  37  may be longer than the sleeve section  40  facing away from the handle  37 . The centric inner sleeve  38  may be surrounded by two slide bushings  41  and  42  on its inner surface. The two identical slide 
         [0025]    The permanent annular magnet  14  may be disposed and retained between the circumferential surface of the inner sleeve  38  facing away from the slide bushings  41 ,  42  and a radially outer annular flange  45  axially protruding from the bottom. Therein, the annular permanent magnet  14  may be inserted in an annular recess of the bottom  36  and adhered therein in centered manner. The annular magnet may extend up to the vicinity of the annular end surface of the upper longer sleeve section  39 . 
         [0026]    The input element  11  may be rotatably supported on the hollow shaft  18  with clearance with the two slide bushings  41  and  42 . This may be achieved in that the two slide bushings  41  and  42  are constituted by sintered bronze bushings or other similar bushings, which result in this clearance support in combination with the hollow shaft  18  of steel or other suitable material. 
         [0027]    By the axial engagement of input element  11  and sensor retainer  15  and the corresponding arrangement of permanent magnet  14  and Hall sensors  25 ,  25 ′, an association both in radial and in axial direction exists in that the Hall sensors  25 ,  25 ′ may be disposed radially in a fixed distance and axially approximately at central level of the annular permanent magnet  14 . 
         [0028]    In a non-illustrated embodiment, a microcontroller may be provided on the board  29  and configured to select which of the Hall sensor  25  or  25 ′ is respectively most advantageous in position to detect the location of the annular magnet  14  based upon the current position of the wheel-shaped input element  11  in order to detect the concerned actuation angle. Thereby, it may be determined which one of the two Hall sensors  25 ,  25 ′ is or is to be respectively active. That is, according to the illustration of the characteristics (digitally converted signal voltage depending on the actuation angle) of the sensors  25  (dashed) and  25 ′ (dot-dashed) in  FIG. 5 , that Hall sensor  25 ,  25 ′ may be respectively consecutively selected by the microcontroller, the characteristic  33  of which (in solid line) may be in the linear region or zone at the corresponding actuation angle such that the resulting overall or output characteristic  33  composed thereof may be linear in the actuation angle range of here about 210° to 220°. If it is required, by toggling to or from the respective Hall sensor  25 ,  25 ′, the respectively most linear behavior may also be detected therein. For example, the best or optimized linearity of the characteristic  33  may result over the angular range of 210° to 220° at an angular distance of the two Hall sensors  25  and  25 ′ of 80°. 
         [0029]    Additionally, the microcontroller may avoid a jump present in the output characteristic in the transition regions caused by switching points from one  25  to the next Hall sensor  25 ′ or vice versa. It is understood that this is also true at an actuation angle of 360° in case of three or four Hall sensors. 
         [0030]    It will be appreciated that several of the above-disclosed and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Also that various presently unforeseen or unanticipated alternatives, modifications, variations or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.