Abstract:
In order to provide an angle sensor in an embodiment, which is axially short in particular and on the other hand radially wider, with a functionality that is as good as possible, on the one hand certain shielding measures against interfering magnetic fields are proposed, and on the other hand a certain geometric design is proposed, in particular comprising an intermediary magnet.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to German Patent Application No. 20200700245.9 filed 8 Jan. 2007 and German Patent Application No. 1020070818759.0 filed 20 Apr. 2007. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not Applicable 
       THE NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
       [0003]    Not Applicable 
       INCORPORATION-BY-REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISC 
       [0004]    Not Applicable. 
       BACKGROUND OF THE INVENTION 
       [0005]    1. Field of the Invention 
         [0006]    The invention relates to a magnetic sensor unit having an angle sensor and an encoder, as they are used in the state of the art as an alternative to potentiometers, particularly comprising a plate-shaped flat embodiment of the angle sensor. 
         [0007]    2. Background Art 
         [0008]    In such magnetic angle sensors, the rotation angle transmission is performed between the encoder element, which is a magnet in this case, and the sensor element, which is provided in particular in the form of an electronic chip (I/C), exclusively by means of magnetic field lines, and above all without a mechanical coupling, so that the sensor element can be housed in a designated space, where it is mechanically completely encapsulated, as long as the magnetic fields of the encoder magnet can penetrate into this space up to the sensor element. 
         [0009]    In the context of such sensor units, angle sensors, operating according to the Hall-principles, or according to the magnetoresistive principle are being used as sensor elements. 
         [0010]    Definitions: The terms, which are mostly used in the claims have the following meaning: 
         [0011]    The angle sensor  1  is the component, which includes the actual sensor element  4 , typically provided as a chip  7 . 
         [0012]    The magnet  50  is the unit, which is typically opposite to the angle sensor  1  and which includes the encoder magnets  50   a, b , which is configured to influence the angle sensor  1 . 
         [0013]    The sensor unit  100  is comprised of the angle sensor and the magnet unit  50 . 
         [0014]    The basic configuration and also the particular dimensions, in particular of the angle sensor of such a sensor unit, are generally determined by the application within tight limits, wherein it is often the case, that the available installation space allows a relatively large radial width of the angle sensor, but only a comparatively smaller axial extension, so that a flat, plate shaped angle sensor is required. 
         [0015]    To the contrary, the magnetic angle sensors commercially available today are generally not optimized for a specific dimension (diameter or length), but mostly provided block shaped, with dimensions, which are approximately equal in all spatial directions. 
       BRIEF SUMMARY OF THE INVENTION 
       [0016]    Thus it is an object of the invention to provide an angle sensor and a sensor unit, formed therewith, which is, on the one hand, optimized in shape and size for a specific exterior configuration (plate shape), and furthermore allows a user, which is independent from interfering magnetic fields being present in the area of application, or not. 
         [0017]    The use also under the influence of interfering magnetic fields is accomplished through a magnetically conductive shielding around the sensor element, which is e.g. comprised of ferromagnetic material. 
         [0018]    The shielding shall be provided, so that it is as tight as possible against the penetration of interfering fields into the inner cavity of the shielding, so that only the use field, generated by the encoder magnet, impacts the sensor element in this location. 
         [0019]    In addition, the shielding, due to its magnetic conductivity, is to serve as a magnetic flux conductor for the magnetic use field, and shall thus effectuate on the one hand a targeted guidance of the use field of the encoder magnet, and optimize its flux guidance, and shall on the other hand conduct the unavoidable scatter portion of this use field into said shielding in a targeted manner. 
         [0020]    For this purpose, the shielding, on the one hand, comprises a sensor shielding, covering at least the longitudinal sides of the sensor element, preferably also the backside of the sensor element, facing away from the encoder element, while the forward face surface pointing towards the encoder magnet, preferably must not be shielded, in order not to avoid the penetration of the use field. 
         [0021]    The shielding furthermore preferably comprises an encoder shielding, shielding the encoder magnet on the longitudinal sides, and on the backside pointing away from the sensor element. 
         [0022]    Preferably, the sensor shielding and the encoder shielding are pot shaped respectively, or dish shaped, in particular provided integral respectively, extending so close to each other with their open sides, or overlapping in axial direction, and reaching into each other in axial direction with a radial distance, which is so small that the penetration of an interfering field into the interior of the shielding is mostly avoided. 
         [0023]    Thus, preferably the sensor shielding and the sensor element are disposed fixated in place, while the encoder shielding is rotatable together with the rotating encoder magnet. 
         [0024]    In order to facilitate an engagement of the use field into the sensor element, regardless of the present rotation position of the encoder relative to the sensor element, the shielding is provided rotation symmetrical to the longitudinal axis of the angle sensor, which is advantageous in particular for multi-turn-applications, since herein the encoder magnet can not only change its angular position relative to the sensor element, but also its axial distance, since said encoder magnet is disposed on the front face of a thread, wherein also the processing of the magnet offset has to be performed with a high resolution, which is hardly possible with sufficient precision under the influence of interfering fields. 
         [0025]    A sufficient shielding allows the use of angle sensors also in locations, where extremely strong interfering fields prevail, like e.g. on the shaft stub of an electric motor, where magnetic angle sensors have not been able to measure with high precision without a shielding so far. 
         [0026]    The material of the shielding thus has a sufficiently high permeability of μ&gt;&gt;100, in particular &gt;1,000, in particular &gt;50,000, in order to facilitate the magnetic flux of the use field, while blocking interfering fields. 
         [0027]    When the shielding has to be disposed very close to the sensor element, a shielding material with a low coercitive field strength Hc, or remanency has to be selected, since otherwise residual fields remain in the shielding material, which can influence the sensor precision. 
         [0028]    At a distance of less than 10 mm to the sensor element a magnet material with a Hc &lt;5 A/cm, better &lt;1 A/cm, better &lt;0.1 A/cm has to be selected. 
         [0029]    With respect to the particular construction method, the magnetic shielding can be a separate component, which is e.g. injection molded from plastic bound ferrite, or sintered from hard ferrite, or comprised of nanocrystalline iron. The shielding, however, can also be an integral component of the housing itself, with the housing being comprised of a respective material, preferably a sleeve shaped cylindrical housing with a preferably closed bottom. 
         [0030]    The housing can comprise a changed, thus enlarged or reduced, inner cross section at its front end, wherein the axial length of the reduced inner cross section corresponds to the rearward offset of the sensor element, and thus the sensor circuit board contacts on the inside at the shoulder between the reduced and the non-reduced inner cross section. The inner cross section of the housing is preferably circular. 
         [0031]    The outer cross section of the housing comprises mounting devices for mounting to a surrounding component, in particular mounting ears, wherein the housing preferably also has a circular exterior circumference. 
         [0032]    The housing can furthermore comprise a zero position marker on the outside at a location on the circumference, in particular a zero position groove, extending in longitudinal direction, whereby the zero position of the sensor element is characterized. 
         [0033]    The forward face surface of the housing of the angle sensor is also closed mechanically, in order to protect the sensor element from detrimental effects. This closure can also be performed by means of a separate front cover, which is applied in a tight manner onto the front rim of the housing. 
         [0034]    If the front cover is made from metal, preferably from non ferromagnetic material like e.g. brass and aluminum, welding onto the housing is preferred, in particular by means of a laser. 
         [0035]    It has proven to be advantageous in particular, to produce such a front cover, which can also be integrally provided together with the remainder of the housing, even from a ferromagnetic material, as long as said front cover, at least in the center, symmetrical to the longitudinal axis, on which the sensor element is disposed, comprises a portion, in which the wall thickness is so small, that the magnetic force of the encoder magnet, disposed on the opposite side, is enough, in order to not only magnetically saturate this small wall thickness of ferromagnetic material, but to furthermore let the magnetic field lines penetrate through this portion into the interior of the angle sensor up to the sensor element. 
         [0036]    This has the advantage that the field lines are conducted through the portion with the low field strength very precisely centric to this portion, and thus also when the outer encoder magnet is displaced eccentrically, tilted with its longitudinal axis, relative to the longitudinal axis of the angle sensor, or comprises other imprecise alignment features. 
         [0037]    If the front cover is comprised of plastic, it is glued on, in particular pressed onto the encasement material, which is still soft, and which is also comprised of plastic, and by which the interior of the sensor housing is cast. 
         [0038]    Thus, the front cover, which is comprised of plastic, can be in particular comprised of translucent plastic, so that an optical indicator in the interior, like e.g. a LED, becomes visible on the circuit board from the outside. 
         [0039]    For the front cover, a shoulder can also be provided in the inner cross section of the housing between a reduced and a non-reduced cross section, in which the front cover contacts. 
         [0040]    Furthermore, the front cover can also be provided as an overreaching pot shaped cover, which is slid over the housing from the open front side and glued, welded, or bolted down thereon. 
         [0041]    Another possibility of the closure is to simply fill the interior of the housing with encasement material up to the front face, so that the encasement material itself constitutes the front cover. In particular a two-layer encasement is thus performed by initially encasing with an elastomeric, in particular silicone resin, or polyurethane resin, until the electric components are completely surrounded therewith. 
         [0042]    Only the residual cavity is then encased with an outer layer of hard material, e.g. epoxy resin, which builds up tensions during hardening, which can damage the electrical components in case of a direct encasement. 
         [0043]    By the same token, the encasement can be performed overall in one layer and with a not completely hardening encasement material, thus an elastomeric like polyurethane. 
         [0044]    Furthermore, there is another possibility to improve the measurement result of the angle sensor, if the indicator magnet is not positioned exactly in the center, and coincident with the longitudinal axis of the angle sensor, but tilted or radially offset relative to it. 
         [0045]    When an intermediary unit is disposed between the angle sensor and the magnet unit, said intermediary unit again has a centering effect. 
         [0046]    For this purpose an intermediary magnet is disposed rotatable around the longitudinal axis in the intermediary unit, wherein the pole axis of the intermediary magnet is disposed preferably transversal to the longitudinal axis, and thus to the rotation axis of the intermediary magnet. 
         [0047]    In a preferred embodiment, this intermediary magnet is supported in the intermediary unit by means of a magneto fluid, which yields particularly low friction forces in the support. 
         [0048]    The intermediary unit can be a simple disk, e.g. made from plastic, which can either be disposed in the interior of the housing of the angle sensor, or in the interior of the housing of the magnet unit, in particular inserted. 
         [0049]    Preferably, the sensor unit can also be provided with two galvanically separated sensor elements, in order to achieve 100% redundancy. Both sensor elements can even be disposed on the same IC. Preferably, then also two separate and galvanically separated cable exits are provided at the sensor unit. 
         [0050]    The processing electronics of the angle sensor are preferably still programmable in a completely finished, also encased state, either by means of at least one additional electrical conductor in the cable, or wirelessly by means of radial or optical signals. 
         [0051]    The angle sensor of the sensor unit is provided plate shaped, thus has a relatively large radial extension, which is larger, in particular at least two times the size of the axial extension, measured on the axis, perpendicular to the plane of the sensor element. Thus, the radial extension is preferably at least three times the size of the axial extension. 
         [0052]    This is accomplished by the sensor element, which is provided in particular as a chip, being disposed in parallel to the main plane of the angle sensor, thus of its housing and preferably on the front side, facing the opening of the housing. In order to allow a simple manufacture, the housing is preferably provided in the shape of a flat pot, which is preferably comprised of ferromagnetic material, iron in particular, which acts as a shielding, or which houses a pot shaped insert made from such material, in which the sensor is housed. The housing comprises a preferably round inner contour and the circuit board, on which the sensor element and the processing unit are disposed, also comprise an analogue, round outer contour, which precisely fits into the inner contour of the housing, in particular contacts on a respective shoulder of the inner cross section of the housing, whereby the axial positioning of the sensor element is predetermined. 
         [0053]    The housing of the angle sensor is mounted to a component in the vicinity by means of mounting devices, which are disposed at the exterior surfaces, preferably at the longitudinal exterior surfaces of the housing, e.g. mounting ears, engaging in clamping grooves, circumferential on the outside of the housing. 
         [0054]    Through a special design of the cable output portion on the closed backside, pointing away from the sensor element, of the mostly pot shaped housing, the same housing can be used for axial, and also for radial cable outputs. 
         [0055]    For this purpose, a portion protrudes on the backside of the housing from a flat base surface, wherein the elevations of said portion are slightly higher than the diameter of the cable to be run out. In this axial view, this raised portion comprises approximately tangential indentations, whose width is slightly larger than the diameter of the cable to be run out. 
         [0056]    Preferably, two, or even several of those indentations are distributed along the circumference. 
         [0057]    At the base of the indentation, a pass-through opening for the cable leads into the interior of the housing. 
         [0058]    The interior flank of the indentation thus transitions without a step into a convex arc shaped contour, which transitions from the indentation into the outer contour of the non-raised portion. 
         [0059]    The outward located flank of the indentation forms a rounded tip with the outer contour of the non-protruding portion, wherein the non-protruding portion, thus the flat base surface, typically comprises a round outer contour. 
         [0060]    Through this embodiment, the cable, which is run out in a tangential direction from the indentation, can either be run out in a tangential direction along the rounded inner flank, or the radial distance from the outer end of the pass-through opening up to the outer contour of the non-protruding portion is used, in order to redirect the cable into an axial position, so that an axial run out path of the cable is created, which does not protrude beyond the outer circumference of the housing. 
         [0061]    Preferably, an inner thread is manufactured into the pass-through opening and adapted to the interior diameter of the cable, so that the cable with its exterior jacket can be threaded into the interior thread, which digs into the exterior circumference of the cable jacket in a self-cutting manner, wherein, on the one hand, a very tight cable input is assured and, on the other hand, a form locked mechanical pull relief for the cable is realized in a simple and space saving manner with respect to the housing. 
         [0062]    In order to avoid the penetration of longitudinal water along the cable into the interior of the housing, which would very quickly render the sensor nonfunctional, also the insulations of the single strands are removed in the interior of the housing in a portion, where the jacket of the cable has already been removed, wherein a sufficient spacing of the strands, where the insulation has been stripped, has to be assured relative to each other, if necessary by means of mechanical spacers. 
         [0063]    The encasement of the interior of the housing is thus performed, so that the portion of the cable, in which the cable jacket ends, and from which the particular strands protrude, is encased, and also the portion of the strands, in which its particular strand insulations end, or have been interrupted. Preferably, the interior of the housing is completely encased up to the forward opening of the housing and thus measures have to be taken, so that no air inclusions are created in the encasement. 
         [0064]    Thereby, longitudinal water cannot penetrate into the housing, neither in the cavities between the electrical conductor and the strand insulation, no in the gaps between the particular strand insulations and the insulating jacket. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0065]    Embodiments are subsequently described in more detail in an exemplary manner as follows: 
           [0066]      FIGS. 1   a - c  show a first embodiment of a sensor unit according to the invention comprising different cable outputs. 
           [0067]      FIGS. 2   a - b  show different types of guidance of an encoder element. 
           [0068]      FIGS. 3   a - d  show different embodiments of an encoder element. 
           [0069]      FIGS. 4   a - b  show particular embodiments of the cable output of the angle sensor. 
           [0070]      FIG. 5  shows a particular front cover. 
           [0071]      FIG. 6  shows a solution with an intermediary unit. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0072]      FIG. 1   a  shows a sensor unit  100  comprised of an angle sensor  1  and a magnet unit  50 , comprising two encoder magnets  50   a, b , cut along the axes  10   a, b , which are preferably shared by the magnet unit  50  and the angle sensor  1 , wherein the encoder is rotatable around its rotation axis  10   b , relative to the typically still standing angle sensor  1 . 
         [0073]    The magnet unit  50  is thus comprised of an encoder core body  51 , typically provided as a symmetrical, in particular rotation symmetrical in top view, circular, e.g. core body  51 , from whose backside a not completely illustrated central pinion  52  protrudes by means of which the core body  51  can be inserted into a blind bore hole of another component, or clamped. 
         [0074]    On or in the forward face surface of the core body  51 , the actual encoder is mounted, comprised in this case of a pot shaped, encoder shielding  101   b , which is also symmetric in top view, in particular rotation symmetric, e.g. circular, which points away with its open side from the core body  51  in the direction of the angle sensor  1 , and in whose open side in this case two encoder magnets  50   a, b  are disposed opposite to each other, and symmetrical to the rotation axis  10   b , so that their pole axes extend in parallel to the axis  10   b , and so that they point in the direction of the angle sensor  1  with different poles. 
         [0075]    The two encoder magnets  50   a, b  are fixated in place in the pot shaped shielding  101   b , since they are encased e.g. by a hardening encasement material  24  in this recess, wherein neither the encasement material  24 , nor the magnets protrude beyond the front rim of the pot shaped encoder shielding  101   b  on the face side. 
         [0076]    Directly opposed to the encoder magnets  50   a, b , the angle sensor  1  is disposed, which also comprises a rotation symmetrical, circular symmetrical, in particular rotation symmetrical, round e.g. base surface, but overall with a larger diameter than the encoder, and with an axial extension, which is less than the diameter, in particular only half the size, or one third the size of the diameter, so that a more plate shaped embodiment of the angle sensor  1  is provided. 
         [0077]    The sensor element  4  of the angle sensor is provided in the form of a chip  7  on a sensor circuit board  8 , which is disposed in parallel to the main circuit board of the angle sensor  1 , and thus with respect to the face surface of the encoder  50 , and thus in the recess of a pot shaped sensor shielding  101   a , facing the encoder. 
         [0078]    The sensor shielding  101   a  is located on the front side of a main circuit board  6 , with which the sensor circuit board  8  is electrically connected through the sensor shielding  101   a , and the main circuit board  6 , on which the remainder of the processing electronics is disposed, contacts on the shoulder between the normal round inner cross section  9  and a reduced inner cross section  9 ′ in the typically circular inner circumference of a pot shaped housing  3 , wherein the larger inner diameter  9  is disposed towards the free end of the pot shaped housing, thus towards the encoder  50 , so that the main circuit board  8  can be placed onto the shoulder from there. 
         [0079]    At the main circuit board  6 , the strands  26   a, b, c  of a cable  26  are electrically connected, wherein said cable is run through the housing  30 , in this case radially to the outside, in order to transmit the signals of the angle sensor  1  to the outside. 
         [0080]    Thus, it is evident that the jacket insulation of the cable  26  ends short within the housing  3 , and is threaded into an inner thread  12 , which is manufactured into the pass-through opening  14  for the cable  26  in the housing  3 , for pull relief. 
         [0081]    It is furthermore evident, that in the portion of the removed cable jacket, also the particular strands  26   a, b, c  are relieved of their respective strand insulations, and held at a distance by mechanical spacers in this portion, in order to avoid an electrical contact. 
         [0082]    The inner free space in the housing  3 , and thus below, and also above the main circuit board  6 , and also the recess in the sensor shielding  101   a  around the sensor element  4  is completely encased respectively by means of a hardening encasement material  24 , whereby all components mentioned above on the one hand are held in position, and on the other hand are protected against a penetration of moisture to the electrical components. In particular, thereby the penetration of longitudinal water between the cable jacket and the particular strands, and also between the strand insulations and the strands into the interior of the angle sensor  1  is avoided. 
         [0083]    Additionally, the face surface  2   a  pointing towards the encoder, thus the open side of the housing  3  is protected by a front cover  25 , which is also configured pot shaped, and which is slid over the open front side of the housing  3  as a slide-over cover, and reaches over it in axial direction over part of its longitudinal sides  11   a, b.    
         [0084]    Since the distance between the encoder  50  and the angle sensor  1  in axial direction is small, and the front cover  25  is comprised of a non-magnetizable material, the sensor element  4  furthermore detects rotating movements of the encoder  50 . 
         [0085]    Furthermore the clamping grooves  27  are illustrated, which are disposed circumferential in the longitudinal sides  11   a, b  in the housing  3 , and/or in the front cover  25  and/or (in the additional figures) in the magnet unit  50 , respectively preferably at the same distance to the adjacent front face, which are used for engaging the clamping claw  28 , and which are thus used for mounting, as shown in some of the Figures. 
         [0086]    The solution in  FIG. 1   b  differs from the one in  FIG. 1   a , in particular through its configuration and through the cable routing of the angle sensor  1 . 
         [0087]    While in the solution according to  FIG. 1   a  the sensor shielding  101   a  has a relatively small base surface, e.g. according to the encoder shielding  101   b , and mostly only receives the sensor element  4  and the supporting sensor circuit board  8 , only the main circuit board  6  is provided in the solution according to  FIG. 1   b , on which the sensor element  4 , and also the entire processing electronics are disposed, and which therefore has a surface, which mostly corresponds to the free inner cross section of the pot shaped housing  3 . 
         [0088]    Accordingly, the sensor shielding  101   a  is also provided pot shaped, but with a substantially larger base surface, so that it extends substantially over the entire inner free surface of the pot shaped housing  3 , and sits in a certain axial position on a respective diameter, a shoulder of the interior diameter of the housing  3 , while the main circuit board  6  itself rests on a respective shoulder in the inner diameter of the pot shaped sensor shielding  101   a.    
         [0089]    Also here, the entire interior cavity of the housing  3  is filled with encasement material  24  on both sides of the shielding  101   a , and also of the main circuit board  6 , and encased for subsequent hardening. 
         [0090]    The cable  26 , in this case, is run axially backward through the bottom of the housing to the outside, but the pull relief and also the sealing against the penetration of longitudinal water is realized analogous to the solution of  FIG. 1   a.    
         [0091]    Additionally the core body  51  of the magnet unit  50  has a base surface in this embodiment, which is the same size, as the face surface  2   a  of the angle sensor  1   
         [0092]    The solution of  FIG. 1   c  corresponds to the one of  FIG. 1   b , besides the fact, that the cable output again extends sideways, thus through the wall of the pot shaped housing  3 , like in the solution according to  FIG. 1   a , and on the backside of the housing  3  a mounting flange  29  protrudes radially, comprising arc shaped axial pass through openings. 
         [0093]      FIG. 2   a  shows a sensor unit, corresponding to the one of  FIG. 1   b , besides the fact, that the walls of the pot shaped housing  3  of the angle sensor  1  in radial direction are provided much thicker, so that in axial direction from the forward to the rear front face along, and in the interior of the side walls, mounting bore holes  13   a, b  can be disposed, through which the angle sensor  1  can be bolted to a surrounding component, as shown e.g. in the application according to  FIG. 2   b.    
         [0094]    There the angle sensor  1  is bolted onto the forward front face of the hollow pinion  15  by means of the mounting bore holes  13   a, b , so that the angle sensor  1  is disposed directly on its forward face surface. 
         [0095]    In the interior of the support housing  15 , the pinion  52  of the encoder core body  51  is supported by bearings  16 , and thus the entire encoder is supported, which is otherwise provided like in the  FIGS. 1   a, b, c.    
         [0096]    The solution of  FIG. 3   a  on the side of the angle sensor  1  corresponds to the solution of  FIG. 1   b , besides the fact, that the open side of the housing  3 , thus towards the encoder, is additionally covered by a front cover  25  in the form of a slide-over cover, as provided in  FIG. 1   a.    
         [0097]    Furthermore, the encoder is provided differently, whose core body  51 , in this case, has a base surface, which has the same size as the one of the housing  3  of the angle sensor  1 , and wherein the core body is not provided plate shaped, but also pot shaped, like the also pot shaped encoder shielding  101   b , which is also received therein. 
         [0098]    Differing from the above solution, the encoder in the solution according to  FIG. 3   b  is again provided with a smaller base surface and in analogy to the  FIG. 1   a.    
         [0099]      FIGS. 4   a  and  4   b  show in a longitudinal sectional view, and in top view from the backside, a special embodiment of the cable output, in particular with two cable outputs from the housing  3  of the angle sensor  1 . 
         [0100]      FIG. 3   c  corresponds to the embodiment of  FIG. 3   b , however the strands  26   a, b, c  of the cable  26  do not have their insulation additionally removed in portions in the interior of the angle sensor  1 . 
         [0101]      FIG. 3   d  corresponds to the solution of  FIG. 3   c , however with an axial cable output, thus through the rear wall of the housing  3 . 
         [0102]    The bottom  3   a  of the housing  3  thus serves as a base surface  17  for a raised portion  18 , extending centrally downward outward there from, which in turn is provided pot shaped, and which comprises two diametrically opposed tangentially oriented indentations  20 , into whose base the pass-through openings  14 , preferably with inner threads  12  for the cable  26 , open out. The pass-through openings  14  thus extend in parallel to the main plane, and thus to the bottom  3   a  of the pot shaped housing  3 , into the side wall of the also pot shaped raised portion  18 , which is provided integral with the remainder of the housing  3 . 
         [0103]    Thus, the configuration of this indentation  20  is quite important, which comprises an inner flank  21  and an outer flank  22 , with respect to the center of the housing  3 , viewed in axial direction. 
         [0104]    In the simplest case the indentation  20  is shown rectangular with a flank in the direction of the extension of the cable  26 , as described above on the left. On the lower right side the preferred embodiment is shown. 
         [0105]    While the outer flank transitions into the outer contour  17 ′ of the base surface  17  in a convex cambered arc shape, viewed in  FIG. 4   b , the inner flank transitions approximately parallel to the outer flank  22  in a concave camber into a tip  23 , which, on the one hand, is formed by the outer contour  17 ′ and, on the other hand by the outer flank  22 . 
         [0106]    As shown by  FIG. 4   b  on the right bottom, the cable  26  can be routed in this manner in the plane of the elevated portion  18 , and in parallel to the bottom  3   a  of the housing  3 , radially, or if required, also tangentially away from the housing  3 , wherein the inner flank  21  avoids a kinking of the cable. 
         [0107]    By the same token, the cable  26 , however, as shown in  FIG. 4   b  in the left upper side, can be run out axially by using the portion of the indentation  20  for redirecting the cable  26  into an axial direction, thus parallel to the longitudinal axis  10  of the housing  3 , wherein this cavity typically suffices, so that the cable  26  hereby does not radially protrude beyond the outer rim of the housing  3 , and also does not have to be kinked too much, since in addition to the bending into the axial direction, also a tangential guidance is performed along the inner flank  21 , and thus the bending is performed in a comparatively gentle manner. 
         [0108]    The  FIGS. 5 and 6  show additional possibilities, how to improve the measuring precision of the sensor unit  100 . 
         [0109]    Thus,  FIG. 5  shows a sensor unit  100 , which corresponds to the one of  FIG. 3   a  besides the fact that in  FIG. 5  an additional intermediary unit  70  is provided in the angle sensor  1 . 
         [0110]    The intermediary unit  70  is a disk shaped body, which is disposed in the housing  3  of the angle sensor  1 , and preferably also within its shielding  101   a , and thus in front of the sensor element  4 , so that it is disposed between the sensor element  4  and the magnet unit  50 . 
         [0111]    The exterior circumference of the intermediary unit  70  can be sized, so it fits the inner circumference of the pot shaped sensor shielding  101   a , and/or the intermediary unit  70  can be mounted to the inside of the front cover  25 , which is provided here as a slide-over cover. 
         [0112]    In the intermediary unit  70 , an encoder magnet  71  is disposed with its pole axis  72  in the direction of the main axis of the disk shaped intermediary unit  70 , and thus perpendicular to the longitudinal axis  10   a  of the angle sensor  1  on this longitudinal axis rotatable in the intermediary unit  70 . 
         [0113]    In order to achieve a support that has as little friction as possible, the encoder magnet  71  is supported in the encoder unit  70  by means of a magnetofluid or ferrofluid  73 , which constitutes a lubricant and the bearing, and which adheres to the magnet, due to very fine iron particles, which are dissolved in the lubricating fluid. 
         [0114]    Thereby, the lubricant always stays in the support gap. Running the bearing dry is avoided without any additional measures. 
         [0115]    The magnet lines of the two encoder magnets  50   a, b  in this case, thus impact the intermediary magnet  71  and rotate with it, and its field lines initially impact the sensor element  4 . 
         [0116]    The advantage is that the intermediary magnet  71  is always in the same defined correct axial position with respect to the sensor element  1 . 
         [0117]    An axial or radial offset of the encoder magnet(s)  50   a, b  relative to the longitudinal axis  10  still causes an angle synchronous engagement of the intermediary magnet  71 , and thus initiates a correct measurement at the sensor element  4 , which would be performed significantly worse under the direct effect of incorrectly placed encoder magnets  50   a, b , relative to the sensor element  4 , under direct effect. 
         [0118]    The solution of  FIG. 6  has the same object and differs from the one in  FIG. 1   a  only through the configuration of the front cover  25 . 
         [0119]    Said front cover is comprised of magnetically conductive material, e.g. soft magnetic highly permeable materials, in particular magnetic NiFe-alloy, e.g. the Permalloy group, which is paradox at first glance, since hereby a shielding effect is accomplished relative to the encoder unit  50 , which is intended to impact the sensor element  4 . 
         [0120]    This is actually the case in the radially exterior portions of the front cover  25 , since it has a relatively large wall thickness. 
         [0121]    In the center portion around the longitudinal axis  10   a , on which also the sensor element  4  is located, the material thickness of the front cover  25 , which shields in principle is reduced strong enough, so that the field strength of the magnet unit  50  suffices in order to not only saturate this small wall thickness magnetically, but to furthermore permeate it with field lines up to the sensor element  4 . 
         [0122]    The advantageous effect is thus that in a not correctly aligned encoder unit  50 , like e.g. shown in  FIG. 6 , in case of an eccentrically slightly offset rotation axis  10   b  of a magnet unit  50 , the field lines originating from the encoder magnets  50   a, b  are centered by the portion of the reduced wall thickness to its center, this means the sensor element  4 , and thus the measurement result is degraded less through the incorrect spatial alignment of the magnet  50  with the angle sensor  1 , than without such configuration of the cover  25 . encoder is rotatable around its rotation axis  10   b , relative to the typically still standing angle sensor  1 . 
         [0123]    The magnet unit  50  is thus comprised of an encoder core body  51 , typically provided as a symmetrical, in particular rotation symmetrical in top view, circular, e.g. core body  51 , from whose backside a not completely illustrated central pinion  52  protrudes by means of which the core body  51  can be inserted into a blind bore hole of another component, or clamped. 
         [0124]    On or in the forward face surface of the core body  51 , the actual encoder is mounted, comprised in this case of a pot shaped, encoder shielding  101   b , which is also symmetric in top view, in particular rotation symmetric, e.g. circular, which points away with its open side from the core body  51  in the direction of the angle sensor  1 , and in whose open side in this case two encoder magnets  50   a, b  are disposed opposite to each other, and symmetrical to the rotation axis  10   b , so that their pole axes extend in parallel to the axis  10   b , and so that they point in the direction of the angle sensor  1  with different poles. 
         [0125]    The two encoder magnets  50   a, b  are fixated in place in the pot shaped shielding  101   b , since they are encased e.g. by a hardening encasement material  24  in this recess, wherein neither the encasement material  24 , nor the magnets protrude beyond the front rim of the pot shaped encoder shielding  101   b  on the face side. 
         [0126]    Directly opposed to the encoder magnets  50   a, b , the angle sensor  1  is disposed, which also comprises a rotation symmetrical, circular symmetrical, in particular rotation symmetrical, round e.g. base surface, but overall with a larger diameter than the encoder, and with an axial extension, which is less than the diameter, in particular only half the size, or one third the size of the diameter, so that a more plate shaped embodiment of the angle sensor  1  is provided. 
         [0127]    The sensor element  4  of the angle sensor is provided in the form of a chip  7  on a sensor circuit board  8 , which is disposed in parallel to the main circuit board of the angle sensor  1 , and thus with respect to the face surface of the encoder  50 , and thus in the recess of a pot shaped sensor shielding  101   a , facing the encoder. 
         [0128]    The sensor shielding  101   a  is located on the front side of a main circuit board  6 , with which the sensor circuit board  8  is electrically connected through the sensor shielding  101   a , and the main circuit board  6 , on which the remainder of the processing electronics is disposed, contacts on the shoulder between the normal round inner cross section  9  and a reduced inner cross section  9 ′ in the typically circular inner circumference of a pot shaped housing  3 , wherein the larger inner diameter  9  is disposed towards the free end of the pot shaped housing, thus towards the encoder  50 , so that the main circuit board  8  can be placed onto the shoulder from there. 
         [0129]    At the main circuit board  6 , the strands  26   a, b, c  of a cable  26  are electrically connected, wherein said cable is run through the housing  30 , in this case radially to the outside, in order to transmit the signals of the angle sensor  1  to the outside. 
         [0130]    Thus, it is evident that the jacket insulation of the cable  26  ends short within the housing  3 , and is threaded into an inner thread  12 , which is manufactured into the pass-through opening  14  for the cable  26  in the housing  3 , for pull relief. 
         [0131]    It is furthermore evident, that in the portion of the removed cable jacket, also the particular strands  26   a, b, c  are relieved of their respective strand insulations, and held at a distance by mechanical spacers in this portion, in order to avoid an electrical contact. 
         [0132]    The inner free space in the housing  3 , and thus below, and also above the main circuit board  6 , and also the recess in the sensor shielding  101   a  around the sensor element  4  is completely encased respectively by means of a hardening encasement material  24 , whereby all components mentioned above on the one hand are held in position, and on the other hand are protected against a penetration of moisture to the electrical components. In particular, thereby the penetration of longitudinal water between the cable jacket and the particular strands, and also between the strand insulations and the strands into the interior of the angle sensor  1  is avoided. 
         [0133]    Additionally, the face surface  2   a  pointing towards the encoder, thus the open side of the housing  3  is protected by a front cover  25 , which is also configured pot shaped, and which is slid over the open front side of the housing  3  as a slide-over cover, and reaches over it in axial direction over part of its longitudinal sides  11   a , b. 
         [0134]    Since the distance between the encoder  50  and the angle sensor  1  in axial direction is small, and the front cover  25  is comprised of a non-magnetizable material, the sensor element  4  furthermore detects rotating movements of the encoder  50 . 
         [0135]    Furthermore the clamping grooves  27  are illustrated, which are disposed circumferential in the longitudinal sides  11   a, b  in the housing  3 , and/or in the front cover  25  and/or (in the additional figures) in the magnet unit  50 , respectively preferably at the same distance to the adjacent front face, which are used for engaging the clamping claw  28 , and which are thus used for mounting, as shown in some of the Figures. 
         [0136]    The solution in  FIG. 1   b  differs from the one in  FIG. 1   a , in particular through its configuration and through the cable routing of the angle sensor  1 . 
         [0137]    While in the solution according to  FIG. 1   a  the sensor shielding  101   a  has a relatively small base surface, e.g. according to the encoder shielding  101   b , and mostly only receives the sensor element  4  and the supporting sensor circuit board  8 , only the main circuit board  6  is provided in the solution according to  FIG. 1   b , on which the sensor element  4 , and also the entire processing electronics are disposed, and which therefore has a surface, which mostly corresponds to the free inner cross section of the pot shaped housing  3 . 
         [0138]    Accordingly, the sensor shielding  101   a  is also provided pot shaped, but with a substantially larger base surface, so that it extends substantially over the entire inner free surface of the pot shaped housing  3 , and sits in a certain axial position on a respective diameter, a shoulder of the interior diameter of the housing  3 , while the main circuit board  6  itself rests on a respective shoulder in the inner diameter of the pot shaped sensor shielding  101   a.    
         [0139]    Also here, the entire interior cavity of the housing  3  is filled with encasement material  24  on both sides of the shielding  101   a , and also of the main circuit board  6 , and encased for subsequent hardening. 
         [0140]    The cable  26 , in this case, is run axially backward through the bottom of the housing to the outside, but the pull relief and also the sealing against the penetration of longitudinal water is realized analogous to the solution of  FIG. 1   a.    
         [0141]    Additionally the core body  51  of the magnet unit  50  has a base surface in this embodiment, which is the same size, as the face surface  2   a  of the angle sensor  1   
         [0142]    The solution of  FIG. 1   c  corresponds to the one of  FIG. 1   b , besides the fact, that the cable output again extends sideways, thus through the wall of the pot shaped housing  3 , like in the solution according to  FIG. 1   a , and on the backside of the housing  3  a mounting flange  29  protrudes radially, comprising arc shaped axial pass through openings. 
         [0143]      FIG. 2   a  shows a sensor unit, corresponding to the one of  FIG. 1   b , besides the fact, that the walls of the pot shaped housing  3  of the angle sensor  1  in radial direction are provided much thicker, so that in axial direction from the forward to the rear front face along, and in the interior of the side walls, mounting bore holes  13   a, b  can be disposed, through which the angle sensor  1  can be bolted to a surrounding component, as shown e.g. in the application according to  FIG. 2   b.    
         [0144]    There the angle sensor  1  is bolted onto the forward front face of the hollow pinion  15  by means of the mounting bore holes  13   a, b , so that the angle sensor  1  is disposed directly on its forward face surface. 
         [0145]    In the interior of the support housing  15 , the pinion  52  of the encoder core body  51  is supported by bearings  16 , and thus the entire encoder is supported, which is otherwise provided like in the  FIGS. 1   a, b, c.    
         [0146]    The solution of  FIG. 3   a  on the side of the angle sensor  1  corresponds to the solution of  FIG. 1   b , besides the fact, that the open side of the housing  3 , thus towards the encoder, is additionally covered by a front cover  25  in the form of a slide-over cover, as provided in  FIG. 1   a.    
         [0147]    Furthermore, the encoder is provided differently, whose core body  51 , in this case, has a base surface, which has the same size as the one of the housing  3  of the angle sensor  1 , and wherein the core body is not provided plate shaped, but also pot shaped, like the also pot shaped encoder shielding  101   b , which is also received therein. 
         [0148]    Differing from the above solution, the encoder in the solution according to  FIG. 3   b  is again provided with a smaller base surface and in analogy to the  FIG. 1   a.    
         [0149]      FIGS. 4   a  and  4   b  show in a longitudinal sectional view, and in top view from the backside, a special embodiment of the cable output, in particular with two cable outputs from the housing  3  of the angle sensor  1 . 
         [0150]      FIG. 3   c  corresponds to the embodiment of  FIG. 3   b , however the strands  26   a, b, c  of the cable  26  do not have their insulation additionally removed in portions in the interior of the angle sensor  1 . 
         [0151]      FIG. 3   d  corresponds to the solution of  FIG. 3   c , however with an axial cable output, thus through the rear wall of the housing  3 . 
         [0152]    The bottom  3   a  of the housing  3  thus serves as a base surface  17  for a raised portion  18 , extending centrally downward outward there from, which in turn is provided pot shaped, and which comprises two diametrically opposed tangentially oriented indentations  20 , into whose base the pass-through openings  14 , preferably with inner threads  12  for the cable  26 , open out. The pass-through openings  14  thus extend in parallel to the main plane, and thus to the bottom  3   a  of the pot shaped housing  3 , into the side wall of the also pot shaped raised portion  18 , which is provided integral with the remainder of the housing  3 . 
         [0153]    Thus, the configuration of this indentation  20  is quite important, which comprises an inner flank  21  and an outer flank  22 , with respect to the center of the housing  3 , viewed in axial direction. 
         [0154]    In the simplest case the indentation  20  is shown rectangular with a flank in the direction of the extension of the cable  26 , as described above on the left. On the lower right side the preferred embodiment is shown. 
         [0155]    While the outer flank transitions into the outer contour  17 ′ of the base surface  17  in a convex cambered arc shape, viewed in  FIG. 4   b , the inner flank transitions approximately parallel to the outer flank  22  in a concave camber into a tip  23 , which, on the one hand, is formed by the outer contour  17 ′ and, on the other hand by the outer flank  22 . 
         [0156]    As shown by  FIG. 4   b  on the right bottom, the cable  26  can be routed in this manner in the plane of the elevated portion  18 , and in parallel to the bottom  3   a  of the housing  3 , radially, or if required, also tangentially away from the housing  3 , wherein the inner flank  21  avoids a kinking of the cable. 
         [0157]    By the same token, the cable  26 , however, as shown in  FIG. 4   b  in the left upper side, can be run out axially by using the portion of the indentation  20  for redirecting the cable  26  into an axial direction, thus parallel to the longitudinal axis  10  of the housing  3 , wherein this cavity typically suffices, so that the cable  26  hereby does not radially protrude beyond the outer rim of the housing  3 , and also does not have to be kinked too much, since in addition to the bending into the axial direction, also a tangential guidance is performed along the inner flank  21 , and thus the bending is performed in a comparatively gentle manner. 
         [0158]    The  FIGS. 5 and 6  show additional possibilities, how to improve the measuring precision of the sensor unit  100 . 
         [0159]    Thus,  FIG. 5  shows a sensor unit  100 , which corresponds to the one of  FIG. 3   a  besides the fact that in  FIG. 5  an additional intermediary unit  70  is provided in the angle sensor  1 . 
         [0160]    The intermediary unit  70  is a disk shaped body, which is disposed in the housing  3  of the angle sensor  1 , and preferably also within its shielding  101   a , and thus in front of the sensor element  4 , so that it is disposed between the sensor element  4  and the magnet unit  50 . 
         [0161]    The exterior circumference of the intermediary unit  70  can be sized, so it fits the inner circumference of the pot shaped sensor shielding  101   a , and/or the intermediary unit  70  can be mounted to the inside of the front cover  25 , which is provided here as a slide-over cover. 
         [0162]    In the intermediary unit  70 , an encoder magnet  71  is disposed with its pole axis  72  in the direction of the main axis of the disk shaped intermediary unit  70 , and thus perpendicular to the longitudinal axis  10   a  of the angle sensor  1  on this longitudinal axis rotatable in the intermediary unit  70 . 
         [0163]    In order to achieve a support that has as little friction as possible, the encoder magnet  71  is supported in the encoder unit  70  by means of a magnetofluid or ferrofluid  73 , which constitutes a lubricant and the bearing, and which adheres to the magnet, due to very fine iron particles, which are dissolved in the lubricating fluid. 
         [0164]    Thereby, the lubricant always stays in the support gap. Running the bearing dry is avoided without any additional measures. 
         [0165]    The magnet lines of the two encoder magnets  50   a, b  in this case, thus impact the intermediary magnet  71  and rotate with it, and its field lines initially impact the sensor element  4 . 
         [0166]    The advantage is that the intermediary magnet  71  is always in the same defined correct axial position with respect to the sensor element  1 . 
         [0167]    An axial or radial offset of the encoder magnet(s)  50   a, b  relative to the longitudinal axis  10  still causes an angle synchronous engagement of the intermediary magnet  71 , and thus initiates a correct measurement at the sensor element  4 , which would be performed significantly worse under the direct effect of incorrectly placed encoder magnets  50   a, b , relative to the sensor element  4 , under direct effect. 
         [0168]    The solution of  FIG. 6  has the same object and differs from the one in  FIG. 1   a  only through the configuration of the front cover  25 . 
         [0169]    Said front cover is comprised of magnetically conductive material, e.g. soft magnetic highly permeable materials, in particular magnetic NiFe-alloy, e.g. the Permalloy group, which is paradox at first glance, since hereby a shielding effect is accomplished relative to the encoder unit  50 , which is intended to impact the sensor element  4 . 
         [0170]    This is actually the case in the radially exterior portions of the front cover  25 , since it has a relatively large wall thickness. 
         [0171]    In the center portion around the longitudinal axis  10   a , on which also the sensor element  4  is located, the material thickness of the front cover  25 , which shields in principle is reduced strong enough, so that the field strength of the magnet unit  50  suffices in order to not only saturate this small wall thickness magnetically, but to furthermore permeate it with field lines up to the sensor element  4 . 
         [0172]    The advantageous effect is thus that in a not correctly aligned encoder unit  50 , like e.g. shown in  FIG. 6 , in case of an eccentrically slightly offset rotation axis  10   b  of a magnet unit  50 , the field lines originating from the encoder magnets  50   a, b  are centered by the portion of the reduced wall thickness to its center, this means the sensor element  4 , and thus the measurement result is degraded less through the incorrect spatial alignment of the magnet  50  with the angle sensor  1 , than without such configuration of the cover  25 .