Abstract:
A device for detecting rotary movement has a rotary part configured to be fixedly connected to a motor shaft and rotate with the motor shaft. One or more sensors are positioned opposite the rotary part and configured to sense rotary movement of the rotary part and transmit signals derived from the rotary movement. A processing unit is connected to the sensor and receives and processes the signals transmitted by the sensor. A receptacle is provided to secure the sensor. The sensor and the receptacle have positioning elements cooperating with one, another so as to adjust a position of the sensor relative to the rotary part in a rotational direction of the rotary part. The device cooperates with a mounting device for mounting and positioning the rotary part relative to the sensor.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a device for detecting rotary movement of a rotary part seated fixedly on a motor shaft, preferably a crankshaft. The device has at least one sensor positioned opposite the rotary part and connected to a detection and/or evaluation unit (processing unit). The sensor is secured in a receptacle. The invention furthermore relates to a mounting device for mounting the rotary part, in particular, for properly positioning the rotary part relative to the sensor in the circumferential direction of the rotary part. 
     2. Description of the Related Art 
     It is known to fixedly mount on a crankshaft of an internal combustion engine a transducer wheel as a rotary part. A sensor is positioned opposite the transducer wheel at a circumferential location of the transducer wheel. It detects the rotary movement of the transducer wheel and sends corresponding signals of the rotary movement to the detection and/or evaluation unit (processing unit). By means of the sensor, the rotary position of the transducer wheel and thus the rotary position of the crankshaft can be determined. In this manner it is, for example, possible to detect when the top dead center of the crankshaft, respectively, of the piston of the internal combustion engine connected to the crankshaft is reached. The transducer wheel and the sensor must be mounted precisely relative to one another in order to be able to precisely detect the rotary position of the crankshaft or the position of the piston. This requires a considerable expenditure. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to embody the device of the aforementioned kind such that the rotary part and the sensor can be mounted in a simple way so as to be precisely aligned relative to one another. 
     In accordance with the present invention, this is achieved in that the receptacle and the sensor have cooperating positioning elements with which the position of the sensor can be adjusted relative to the rotary part in the rotary direction thereof. This is furthermore achieved in that the rotary part can be mounted with a mounting device and in that the rotary part can be positioned in its circumferential direction relative to the sensor by the mounting device. 
     In the device according to the invention, the positioning elements of the receptacle and of the sensor cooperate with one another. This makes it possible to fasten the sensor simply and precisely within a short period of time in the receptacle. By means of the positioning elements it is ensured that the sensor can be adjusted precisely in the rotary direction relative to the rotary part so that the sensor can detect reliably the rotary movement of the rotary part. The rotary part can be mounted by means of the mounting device in a simple way but still precisely in regard to its required position. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING 
     In the drawing: 
     FIG. 1 is a perspective illustration of the device according to the invention together with a mounting device, by which the transducer wheel and the sensor are mounted position-precisely relative to one another on a carrier; 
     FIG. 2 shows the mounting device in a perspective illustration in a view from below; 
     FIG. 3 is a perspective and enlarged illustration of the sensor according to FIG. 1; 
     FIG. 4 shows on an enlarged scale the receptacle of the carrier for the sensor; 
     FIG. 5 is a perspective illustration in a view from below of the mounting device with mounted transducer wheel; and 
     FIG. 6 is a perspective illustration of a second embodiment of the device according to the invention together with a mounting device. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With the mounting devices to be disclosed in detail in the following, a transducer wheel (FIGS. 1 through 6) and a sensor are position-precisely mounted relative to one another on a carrier or a rotary shaft seal. The carrier or the rotary shaft seal are mounted on an engine block from which a crankshaft projects. The transducer wheel is fixedly seated on the crankshaft. The sensor detects the signals generated by the transducer wheel and transmits them to a processing unit. The processing unit monitors by means of the transmitted signals the proper function and position of the crankshaft provided with the transducer wheel or the rotary shaft seal. 
     In the embodiment according to FIGS. 1 through 5, an annular carrier  1  is fastened to an engine block (not shown). For this purpose, the carrier  1  which is, for example, formed as a sheet metal flange, is provided with fastening openings  2  for screws etc. with which the carrier  1  can be mounted on the engine block. A sensor  3  is fastened on the carrier  1  and is mounted opposite the transducer wheel  4 . The transducer wheel  4  is fixedly connected to the crankshaft projecting from the engine block and penetrating the carrier  1 . On the circumference of the carrier  1 , as shown in FIG. 4, a cutout  5  is provided in which a receptacle  6  for the sensor  3  is provided. The receptacle  6  in cross-section is U-shaped and has a stay  7  which extends radially and has at its two longitudinal edges perpendicularly projecting legs  8  and  9 . The stay  7  and the legs  8 ,  9  are advantageously a monolithic part. The stay  7  has at half its width a radially extending projection  10  as a reinforcement which is in the form of a corresponding embossment formed in the stay  7 . The legs  8 ,  9  are spaced with minimal spacing from the end face  11  of the stay  7 . Moreover, they have a minimal spacing from the back wall  12  delimiting the cutout  5 . 
     For producing the receptacle  6 , the carrier  1  is stamped within its circumferential area. Subsequently, the legs  8 ,  9  are bent upwardly out of the plane of the carrier  1 . In this way, the receptacle  6  can be manufactured simply and inexpensively. The leg  9  is positioned at a spacing from the neighboring side wall  13  of the cutout  5 . 
     The oppositely positioned leg  8  is spaced from a counter bracket  14  which is bent substantially at a right angle out of the plane of the carrier  1  at a rim portion thereof . The counter bracket  14  has a rectangular contour and is positioned approximately perpendicularly to the legs  8 ,  9  of the receptacle  6 . The counter bracket  14  has a backside  15  which is facing the center of the annular carrier  1 , and at this backside  15  a nut  16  is fastened which is positioned coaxially to an opening  17  penetrating the counter bracket  14 . The counter bracket  14  is radially recessed relative to the end face  11  of the stay  7  of the receptacle  6 . 
     The annular carrier  1  is otherwise matched with respect to its cross-sectional design to the engine block to which it is to be fastened. 
     The sensor  3  must have a precisely defined position relative to the transducer wheel  4 . The precise mounting position of the sensor  3  is realized by the receptacle  6  and the counter bracket  14  on the carrier  1 . As shown in FIG. 3, the sensor  3  has a parallelepipedal sensor housing  18  whose underside  19  is planar. The underside  19  has a step  20  extending over its length and adjacent thereto a planar support surface  21 . The support surface  21  extends between the two oppositely arranged parallel sidewalls  22  and  23  of the sensor housing  18 . The sensor housing  18  rests in the mounted position by means of its support surface  21  areally (with a large contact area) against the stay  7  of the receptacle  6  on the carrier  1 . The spacing between the two parallel sidewalls  22 ,  23  of the sensor housing  18  corresponds to the spacing between the two legs  8 ,  9  of the receptacle  6 . Accordingly, the sensor housing  18  rests in the mounted position areally (with a large contact area) against the facing inner sides of the legs  8 ,  9  of the sensor receptacle  6 . 
     A recess  24 , rectangular in cross-section, is centrally arranged in the support surface  21 . The projection  10  on the stay  7  of the receptacle  6  engages the recess  24  in the mounted position of the sensor  3 . The width of the recess  24  corresponds approximately to the width of the projection  10 . The recess  24  is open at the backside  25  of the sensor housing  18  and ends in the opposite direction with minimal spacing relative to the step  20 . The radial mounting position of the sensor  3  is reached when the sensor housing  18  has been pushed to such an extent onto the stay  7  of the receptacle  6  that a connecting bracket  38  of the sensor  3  (FIG. 3) contacts the counter bracket  14 . 
     At the level of the step  20  centering springs  28 ,  29  project from the sidewalls  22 ,  23 . They are of identical design and arranged mirror-symmetrically to one another. The two centering springs  28 ,  29  have a connecting portion  30 ,  31  extending perpendicularly away from the sidewalls  22 ,  23 . The connecting portions  30 ,  31  have a transition portion into a hook part  32 ,  33 . The hook parts  32 ,  33  are oriented in a direction toward the sidewalls  22 ,  23  of the sensor housing  18 . The free ends  34 ,  35  of the hook parts  32 ,  33  are bent in opposite directions to one another so that they face away from the sidewalls  22 ,  23 . The two centering springs  28 ,  29  are positioned in a common plane that is located perpendicularly to the sidewalls  22 ,  23  of the sensor housing  18  and extends advantageously parallel to the underside  19  of the sensor housing  18 . The free ends  34 ,  35  of the hook parts  32 ,  33  are positioned at a spacing from the sidewalls  22 ,  23  of the sensor housing  18 . 
     By means of the centering springs  28 ,  29 , the sensor  3  is centered relative. to the receptacle  6 . The sensor  3  is pushed in the manner disclosed supra onto the stay  7  of the receptacle  6 , and the projection  10  of the stay  7  engages the recess  24  in the support surface  21  of the sensor housing  18 . The centering springs  28 ,  29  rest with elastic tension against the outer sides of the legs  8 ,  9  of the receptacle  6  which face away from one another. Since the free ends  34 ,  35  of the hook parts  32 ,  33  are oriented away from the sidewalls  22 ,  23  of the sensor housing  18 , the centering springs  28 ,  29  can be easily pushed onto the legs  8 ,  9  of the receptacle  6 . Because of the elastic tension, the sensor  3  is precisely radially aligned relative to the carrier  1 . 
     The bracket-like connecting part  36  projects perpendicularly from the side wall  22  of the sensor housing  18  and, as shown in FIG. 3, is stiffened at its backside by it least one rib  37 . The connecting part  36  connects the sensor housing  18  with the connecting bracket  38  which has a planar backside  39  resting areally (with a large contact area) against the counter bracket  14 . The connecting bracket  38  has an opening  40  penetrating it which is aligned with the opening  17  of the counter bracket  14  in the mounted position of the sensor  3 . A fastener in the form of a threaded bolt  41  (FIG. 1) is pushed through the two openings  40 ,  17  and threaded into the nut  16  at the backside of the counter bracket  14 . In this way, the sensor  3  is fixedly connected to the carrier  1 . The centering springs  28 ,  29  ensure a perfect circumferential alignment of the sensor  3  relative to the transducer wheel  4 . By means of the contacting brackets  14 ,  38 , the sensor  3  can be reliably fastened on the carrier  1  in the aligned position. By means of the threaded bolt  41  the sensor  3  can also be easily removed or exchanged. The sensor receptacle  6  and the counter bracket  14 , which, as disclosed supra, are advantageously monolithic components of the annular carrier  1 , can be precisely positioned already during the manufacture of the carrier  1  so that the sensor  3 , in turn, can be precisely positioned by simply slipping it into the receptacle  6  and fastening it on the carrier  1  by means of the threaded bolt  41 . 
     The transducer wheel  4  is provided at its circumference with teeth  42  extending parallel to the axis of the crankshaft. The transducer wheel  4  must be mounted in a precise position relative to the sensor  3 . In order to ensure this, a mounting device  43  is provided (FIGS. 1 and 2) with which such a precise positioning is possible. 
     The mounting device  43  has an annular base member  44  whose outer rim  45  is thicker than the remaining portion of the base member  44 . The rim  45  extends in the direction toward the carrier  1  in the mounting position. The rim  45  is provided with cutouts  46  which are distributed about its circumference and extend into the base member  44 . A ring  47  projects from the underside of the disc-shaped base member  44 . The ring  47  and the underside face the carrier  1  in the mounted position. The axis of the ring  47  coincides with the axis of the base member  44 . The ring  47  is radially inwardly spaced from the thick rim  45  and surrounds with radial spacing a central ring  48  which projects in the same direction from the base member  44  as the ring  47 . The axis of the ring  48  also coincides with the axis of the base member  44 . The ring  47  has the task of centering the transducer wheel  4  during mounting. As illustrated in FIG. 5, the annular transducer wheel  4  rests with its radially inner rim  49  against the outer mantle of the ring  47 . The transducer wheel  4  itself rests against the bottom of the base member  44 . 
     In order to bring the transducer wheel  4  into a defined position relative to the mounting device  43 , two first positioning members or noses  50  project perpendicularly from the base member  44  directly adjacent to the rim  45 . They are circumferentially spaced from one another and engage two openings  51  of the transducer wheel  4  (FIG.  5 ). The row of transducer teeth  42  is interrupted in the area between the two first positioning members or noses  50 . These first positioning members or noses  50  ensure in a simple way that the transducer wheel  4  is in a precisely defined position with respect to the mounting device  43  for mounting on the crankshaft. 
     For mounting, the transducer wheel  4  is first inserted into the mounting device  43  such that the first positioning noses  50  engage in the disclosed manner the openings  51  of the transducer wheel  4 . The transducer wheel  4  is inserted such that the teeth  42  of the transducer wheel  4  extend in the same direction as the thick rim  45  of the mounting device  43 . The teeth  42  do not project past the rim  45  but are advantageously slightly axially recessed relative to the rim  45 . 
     The mounting device  43  with the mounted transducer wheel  4  is placed onto the carrier  1  (FIG.  1 ). In order to achieve a precise alignment of the transducer wheel  4  positioned in the mounting device  43  relative to the sensor  3 , the mounting device  43  is provided with two second positioning or centering members  52  (FIG. 5) that are positioned circumferentially spaced relative to one another. They project axially from the rim  45  of the mounting device  43 . Their spacing is selected such that they rest in the mounted position against the outer sides of the legs  8 ,  9  of the receptacle  6  facing away from one another. The mounting device  43  is placed onto the carrier  1  such that the two second positioning (centering) members  52  embrace the legs  8 ,  9  of the sensor receptacle  6 . 
     The rim  45  of the mounting device  43  in the area of the centering members (noses)  52  is shorter than in the remaining area (FIGS.  1  and  2 ). Accordingly, a depression  53  is formed which has such a length in a circumferential direction of the mounting device  43  that the sensor receptacle  6  and the counter bracket  14  are located within this depression  53  in the mounted position. In the mounted position according to FIG. 1, the thick rim  45  of the mounting device  43  rests against the carrier  1  in the vicinity of the circumferential area. 
     By means of the second centering members  52  a precise radial positioning of the mounting device  43  and the transducer wheel  4  received therein is realized. When subsequently the sensor  3  is pushed into the sensor receptacle  6  in the manner disclosed above and fastened to the counter bracket  14 , the sensor  3  and the transducer wheel  4  have a precisely defined position relative to one another. After screwing the sensor  3  to the carrier  1 , the mounting device  43  is axially removed. The transducer wheel  4  is seated fixedly on the crankshaft. The central ring  48  of the mounting device  43  ensures an axial pre-centering relative to the crankshaft 
     In the described manner, by means of the mounting device  43  the relative position of the transducer wheel  4  and of the sensor  3  to one another can be adjusted precisely, without requiring complex adjusting steps. Due to the disclosed configuration of the mounting device  43  and of the carrier  1 , the two parts ( 3 ,  4 ) can be easily positioned in a precise location relative to one another. During the mounting process the mounting device  43  will automatically be pushed off because the crankshaft presses onto the ring  47  of the mounting device  43 . 
     The centering noses  52  are positioned radially at the level of the positioning noses  50 . When the mounting device  43  together with the transducer wheel  4  is connected to the carrier  1  and the sensor  3  is pushed into the receptacle  6 , the sensor  3  is positioned between the two centering noses  52 , when viewed in the radial direction. The tooth gap of the transducer wheel  4  is then positioned accordingly also opposite the sensor  3 . In the represented embodiment, the tooth gap of the transducer wheel  4  is positioned opposite the sensor  3  when the crankshaft moves through its top dead center. Accordingly, the rpm of the crankshaft can be easily monitored during operation of the engine. 
     The first positioning noses  50  are advantageously configured such that the transducer wheel  4  is seated with slight tension in the mounting device  43 . The second positioning members (centering noses)  52  can also be configured such that they rest with tension against the. legs  8 ,  9  of the sensor receptacle  6 . This ensures a simple and precise positioning. 
     FIG. 6 shows an embodiment in which, instead of a plate-like sheet metal carrier  1  a sheet metal carrier is used which has radial symmetry. It is formed by a radially projecting flange of a radial shaft seal (not shown) which is pressed into a bore of the engine block. The sensor receptacle  6  is machined into the flange and is of the same configuration as in the previously disclosed embodiment. The radial shaft seal, as is known in the art, has a support on which the radially projecting flange is provided. External to the sealing area the radial shaft seal is provided with a penetration at the level of the sensor  3  so that signals derived from the transducer wheel  54  can be detected. In the circumferential area, the transducer wheel  54  is provided with embedded magnets (not shown) arranged in a row in the circumferential direction and cooperating with the sensor  3 . The transducer wheel  54  is mounted with the aid of the mounting device  43 . It is essentially of identical design as disclosed in the previous embodiment. It has an annular base member  44  which is provided with recesses  46  distributed about its circumference. In contrast to the afore described embodiment, the outer rim  45  is not thicker. The radially inner rim  55  of the base member  44  is configured as a flange and extends in the mounted position in the direction toward the annular carrier  1 . It is fastened at a corresponding engine block in a suitable manner and comprises the sensor receptacle  6  and the counter bracket  14  for attachment of the sensor  3  with its connecting bracket  38 . The, sensor housing  18  is provided with the two centering springs, only the centering spring  29  being visible in FIG.  6 . The fastening of the sensor  3  and its positioning are realized in the same manner as in the preceding disclosed embodiment. 
     The transducer wheel  54  is pushed into the mounting device  43  which, in analogy to the preceding embodiment, is configured as a mounting mandrel. The position fixation of the transducerwheel  54  is realized by the upwardly projecting rim  55  against which the transducer wheel  54  rests with its inner circumference. In accordance with the, previous embodiment, first the transducer wheel  54  is precisely inserted and positioned in the mounting device  43 . The mounting device  43  is subsequently introduced into the carrier, and the centering noses  52  embrace the outer sides of the legs  8 ,  9  of the sensor receptacle  6  (FIG.  4 ). Subsequently, the sensor  3  is inserted into the receptacle  6 , and the centering springs  28 ,  29  come to rest against the outer sides of the legs  8 ,  9  of the sensor receptacle  6  which face away from one another. The sensor  3  is then fastened in the mounted positioned with the threaded bolt  41  on the counter bracket  14  of the carrier  1 . In this embodiment, the mounting device  43  is also automatically removed (by the crankshaft) during the mounting process. 
     In a further embodiment (not illustrated) the sensor housing  18  is not provided with centering springs  28 ,  29 . The positioning is realized in this case by means of the sidewalls  22 ,  23  of the sensor housing  18  which rest against the facing inner sides of the legs  8 ,  9  of the sensor receptacle  6  and ensure the positioning of the sensor  3  in cooperation with these legs. In this case it is advantageous when the spacing of the sidewalls  22 ,  23  is slightly smaller than the spacing of the legs  8 ,  9  of the sensor receptacle  6 . The sidewalls  22 ,  23  and the legs  8 ,  9  of the sensor receptacle  6  form a clearance fit. The smaller this clearance fit (play), the higher the positioning precision. Fastening of such a sensor is carried out in the manner described supra by the connecting bracket  38  which is fastened by means of the threaded bolt  41  to the counter bracket  14  of the carrier  1 . The sensor housing  18  can be used in the embodiments illustrated in FIGS. 1 through 6. 
     While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.