Abstract:
A way sensor arrangement ( 2 ) for detecting the displacement of a mechanical component in relation to another component. The way sensor arrangement having a sensor housing ( 4 ) that is firmly mounted to a first (gear case  6 ) of these two components and a sensor carriage ( 12 ) that interacts with the housing and can be coupled to the second component (shift rail  18 ). The invention provides that the sensor carriage ( 12 ) is mounted in the sensor housing ( 4 ) displaceably in the direction of displacement of the displaceable component (shift rail  18 ) and that mutually interacting coupling device (catch projection  14,  catch recess  16 ) are provided on the sensor carriage ( 12 ) and on the second component (shift rail  18 ), which can mutually engage with each other.

Description:
This application claims priority from German Application Serial No. 10 2005 004 489.1 filed Feb. 1, 2005. 
   FIELD OF THE INVENTION 
   The invention relates to a way sensor arrangement as well as a method for mounting such a way sensor arrangement. 
   BACKGROUND OF THE INVENTION 
   Way sensors are used in various technical applications. A typical application includes mechanical gearboxes where the gear wheels are shifted by way of shifting forks, which are connected to manually, semi-automatically or automatically actuated, horizontally displaceable shift rails. The displacement of a shift rail detected by way of the way sensor arrangement is processed further as a way signal in a functional control unit, for example, in order to optimize the synchronization process in a synchronized transmission. 
   A synchronized gearbox is already known from DE 196 52 971 A1 where, in addition to the mechanical synchronizing devices, a drive device for modifying the rotational speed of a jack shaft is provided, with the aid of which a rotational speed adaptation of the shafts to be coupled with each other is supposed to be brought about during a gear change. Way signals of the shift rail activated during a gear change are input in the functional control unit and the drive device, among other things. The aforementioned publication contains no information about the exact configuration of the way sensor arrangement. 
   In conventional way, the sensor housing is mounted to a first component and, separately from this, the sensor carriage is mounted to a second component. 
   The term “sensor housing” is interpreted below as that part of the way sensor arrangement which records the displacement of the sensor carriage and forwards it as a way signal to the functional control unit, for example, via a printed circuit board with transmitting coil arranged therein. The disadvantage with such way sensor arrangements is that in addition, assembly is required for the separate installation of the sensor carriage. Above and beyond this, the risk that the installation of the sensor carriage is accidentally omitted during manufacture of the gearbox cannot be ruled out, particularly when the assembly is performed in a different location than the assembly of the sensor housing. Another disadvantage is that the interface between the sensor carriage and sensor housing is difficult to manage, i.e., that a zero point adjustment of the two components in relation to each other is difficult to achieve, and that varying air gap tolerances between the first and second components caused by manufacturing tolerances may impair the transmission of the signal, particularly that larger air gap tolerances impact negatively on signal accuracy. 
   Against this background, it is the object of the invention to create a way sensor arrangement as well as a method for the assembly thereof, which have the following advantages compared to conventional systems: assembly is supposed to be simpler and more reliable; the interface and air gap tolerance problems are supposed to be reduced; the sensor carriage is supposed to remain attached captively to the sensor housing at all times, and the sensor carriage is supposed to be connected easily to the second component without separate assembly. 
   SUMMARY OF THE INVENTION 
   The invention is based on the realization that the above-described technical objective is best achieved in that the sensor housing and the sensor carriage form an inseparable unit that is produced following the rules of precision manufacture, wherein the sensor carriage during assembly of the way sensor arrangement is connected to that component, the displacement movement of which is supposed to be measured. 
   Accordingly, the invention proceeds from a way sensor arrangement that is used to detect the displacement of a mechanical component in relation to another component, which arrangement comprises a sensor housing or the like that can be mounted to a first component and a sensor carriage that interacts with the first component and can be coupled to the second component. 
   The following measures are suggested to accomplish the objective posed, wherein the position and directional information relates to the way sensor arrangement and/or the sensor housing in a state in which it is mounted to the first component. The sensor carriage is mounted in the sensor housing such that it can be displaced in the direction of the displacement of the displaceable component and, on one hand, mutually interacting coupling device are provided on the sensor carriage and, on the other hand, on the second component, which means can engage with each other. 
   In one configuration of the invention, the coupling device comprises spring-loaded prestressed detent devices, which automatically latch in a defined displacement position of the first component in relation to the second component. This way, the sensor carriage can be coupled extremely easily to the displaceable component in that the sensor housing with the sensor carriage seated therein is first mounted to the first component independently from the position of the displaceable component, and then the second displaceable component is slid in the defined displacement position. 
   One constructional configuration of the way sensor arrangement provides that catch elements that are pre-tensioned by way of spring devices are arranged on the sensor carriage, which elements in the case of a defined displacement position of the displaceable component latch to the catch elements provided in this component. 
   To ensure that the way sensor arrangement (following completion of the assembly) has an exact zero point adjustment, for example, it is necessary that the sensor carriage assumes a defined position in the sensor housing the moment it is coupled to the second component. Accordingly, it is required that the sensor carriage is fixed in a defined position in the sensor housing in the “as delivered state” and in the assembled state, i.e., the state following assembly of the sensor housing to the first component, and prior to being coupled to the second component. 
   In order to ensure this defined position of the sensor carriage in the “as delivered state” and the assembly state, it is provided according to a preferred configuration of the invention that the catch elements of the sensor carriage and/or components connected thereto can be adjusted in relation to the sensor housing between a first completely extended end position corresponding to the “as delivered state” and a second completely retracted end position corresponding to the assembly state, and that in the first and second end positions retention devices that are formed on the catch elements and/or the components connected thereto as well as on the sensor housing mutually engage with each other. 
   The retention devices prevent a displacement of the sensor carriage in the sensor housing, wherein the same are disengaged when they assume an intermediate position between the first and the second end positions corresponding to an operating state, thus allowing the sensor carriage to be displaced together with the second component to effectively measure the displacement. 
   In the “as delivered state” of the way sensor arrangement, the catch elements assume their first completely extended end position. In this case, the sensor carriage, as described above, is locked in a defined position in the displacement direction. During assembly of the way sensor arrangement to the first component, the catch elements rest against the second component and are pushed back by it into the second end position in which the sensor carriage is also locked in the displacement direction. 
   During a subsequent displacement of the second component, the catch elements formed on this component are congruent with the catch elements formed on the sensor carriage so that they latch with each other, thus disengaging the retention devices and releasing the sensor carriage for displacement in relation to the sensor housing. 
   In a first construction variation of the way sensor arrangement of the invention, the sensor carriage comprises a cursor tab that can be adjusted on the sensor housing to a first end position determined by the stop and a second end position in a direction perpendicular to the displacement movement of the sensor carriage, which a catch projection is configured on a cursor tab which can engage with a catch recess on the second component. 
   The cursor tab carries a cursor carrier that can be displaced in the same direction, where spring devices are arranged between the cursor tab and the cursor carrier which, on one hand, press the cursor carrier against the sensor housing and, on the other hand, push the cursor tab in the direction of the first end position. The cursor tab and the cursor carrier are forced apart by the associated spring devices and are clamped between the sensor housing and the second component. 
   Stop surfaces defining the first end position and/or the second end position of the cursor tab are provided with mutually interacting retention projections or retention recesses, which prevent a displacement of the sensor carriage in relation to the sensor housing in these end positions. 
   In another construction variation of the way sensor arrangement, the sensor carriage comprises a cursor carrier, which cannot be displaced in a direction perpendicular to the displacement direction and on which at least one latch or the like is arranged, which can be moved from a first end position to a second end position transversely to the displacement direction by way of a spring-loaded elastic arm, which latch engages in catch recesses formed on the sensor housing in the two end positions. 
   This construction variation is simpler in terms of design than the first construction variation described above, as will be illustrated based in an example. 
   However, it meets the aforementioned requirement of a defined position of the sensor carriage in the “as delivered state” and in the assembly state in a similar manner. 
   When using a way sensor arrangement, according to the second construction variation for capturing the displacement of a shift rail or the like, having a substantially round cross-section as that encountered in the abovementioned mechanical gearboxes, according to the invention, it is provided that the cursor carrier comprises two spring-loaded, elastic arched arms that encompass the gearshift rod and carry a latch, respectively, and that a peripheral groove is formed on the shift rail for receiving the latches as will be explained in more detail with an example of the embodiment. 
   A method for mounting a way sensor arrangement of the kind described above comprises, in general, the following steps: 
   First, the sensor housing is mounted to the first component and then the coupling devices of the sensor carriage and of the second component are mutually engaged. When the coupling device includes spring-loaded, pre-tensioned detent devices, the second component—following the installation of the way sensor arrangement on the first component—is moved into the defined displacement position at which the detent devices automatically snap in place. 
   If the catch elements can be adjusted between two end positions in which retention devices are engaged and prevent a displacement of the sensor carriage in the sensor housing, the assembly method provides that the sensor housing is mounted to the first component, wherein the catch elements are adjusted from the first end position, which locks the sensor carriage in the displacement direction into the second locking end position by coming in contact with the second component. 
   Subsequently, the second component is adjusted to the defined displacement position, where the catch elements move from the second end position to an intermediate position in which the retention devices are disengaged. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will now be described, by way of example, with reference to the accompanying drawings in which: 
       FIG. 1  is a schematic cross-sectional view of a way sensor arrangement with a sensor carriage, which comprises a cursor carrier, a cursor tab and spring devices arranged between them; 
       FIG. 2  is a perspective view of a way sensor arrangement with a sensor carriage, which comprises a cursor carrier with two spring-loaded elastic arms, and 
       FIG. 3  is a cross-sectional detailed view of  FIG. 2 . 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The way sensor arrangement, as seen in  FIG. 1  and described in the following, shows an arrangement used, for example, in a mechanical gearbox, in order to detect the displacement of a shift rail. 
   A way sensor arrangement  2  comprises a sensor housing  4 , which is mounted in a gear housing  6  in a way that is not shown in detail. A printed circuit board  3 , on which the coil is not shown, is arranged on the sensor housing  4 , which board is used to transmit a sensed way signal to the aforementioned functional control unit of the gearbox. 
   A sensor carriage  12 , which comprises a cursor tab  8  and a cursor carrier  10  is arranged in or on the sensor housing  4  displaceably in principle in a direction perpendicular to the drawing plane. It can, however, also be locked thereon, as will be illustrated below. A catch projection  14  is arranged on the cursor tab  8 , which projection can engage with a catch recess  16  configured as a peripheral groove of a shift rail  18  that can, likewise, be displaced in a direction perpendicular to the drawing plane. 
   The cursor tab  8  is mounted on the cursor carrier  10  displaceably in a direction that is perpendicular to the displacement movement of the sensor carriage  12  and corresponds to a double arrow  20 . In the illustrated example, spring device  22  is a helical compression spring, which is arranged between the cursor carrier  10  and the cursor tab  8  and force the cursor carrier  10  and the cursor tab  8  apart, wherein the cursor carrier  10  is held in the illustrated completely straddled position by stop devices  24  and/or  26  formed on the cursor tab  8  and/or cursor carrier  10 . 
   The cursor tab  8  is provided with lateral brackets  28 ,  30 , which apply a load on brackets  32 ,  34  provided on the sensor housing  4 , as is shown in  FIG. 1 . In doing so, stop surfaces  36  and/or  38  formed on the brackets  28 ,  30  on one hand and/or on the brackets  32 ,  34  on the other hand are mutually brought in contact with each other by the spring devices  22 . 
   It should be noted here that the arrangement illustrated in  FIG. 1  represents way sensor arrangement  2  “as delivered,” for example, at the facility of a gear manufacturer, i.e., a state before the way sensor arrangement  2  is mounted in the gear case  6 . 
     FIG. 1  further shows that mutually interacting retention projections  40  and/or retention recesses  42  are formed on the stop surfaces  36  and/or  38 , which projections and/or recesses in the illustrated “as delivered state” are mutually engaged and prevent a displacement of the sensor carriage  12  in relation to the sensor housing  4  in a direction perpendicular to the drawing plane so that the sensor carriage  12  has a defined position in relation to the sensor housing  4 . 
   When the way sensor arrangement  2  and/or the sensor housing  4  is connected to the gear case  6 , initially the catch projection  14  formed on the cursor tab  8  rests against an outer circumference  44  of the shift rail  18 . The cursor tab  8  is thus displaced in the direction of an arrow  46  towards the cursor carrier  10  until stop surfaces  48  formed on the brackets  32  and  34  come in contact with stop surfaces  50  formed on the cursor tab  8 . In turn, this leads to the fact that the retention recesses  52  and/or retention projections  54  formed on the stop surfaces  48  and/or  50  mutually engage, so that even in this position which is referred to as the assembly state, the sensor carriage  12  is locked in relation to the sensor housing  4  in the displacement direction, i.e., in a direction perpendicular to the drawing plane. 
   The shift rail  18  is subsequently displaced so far out of the drawing plane that the catch projection  14  snaps into the catch recess  16 , wherein the catch projection  14  is supported on a bottom  56  of the catch recess  14 . In this position, which is referred to as the operating state, neither the stop surfaces  36 ,  38  nor the stop surfaces  48 ,  50  are in contact with each other, so that the associated retention projections  40 ,  42  and/or  52 ,  54  are not engaged and the sensor carriage  8  can be displaced in the displacement direction in relation to the sensor housing  4 . 
   This concludes the assembly of the way sensor arrangement  2  in the gear case  6 . 
     FIG. 2  shows another embodiment of a way sensor arrangement  60  which, in turn, can be used to record the displacement of a shift rail in a mechanical gearbox. 
   A sensor carriage  64  is arranged displaceably in the direction of a double arrow  66  in a sensor housing  62 . The sensor carriage  64  comprises a cursor tab  68 , on the bottom side of which two spring-loaded elastic arms  70 ,  72  are arranged. On the outer ends of the two arms  70  and/or  72  laterally projecting latches  74  and/or  76  are arranged, which engage in guide grooves  78  and/or  80  that are formed on the sensor housing and extend in the displacement direction indicated by the double arrow  66 . 
   The guide grooves  78 ,  80  comprise recesses on the top and bottom in certain locations of their longitudinal extensions, of which recesses  FIG. 2  shows only upper recesses  82  and/or  84  for clarity reasons. These recesses can receive the latches  74  and/or  76  when the arms  70  and/or  72  are bent upward or downward, as will be described below in detail based on  FIG. 3 . 
   In the “as delivered” state shown in  FIG. 2 , the arms  70 ,  72  are largely relaxed and engage in (not illustrated) lower recesses of the guide grooves  78  and  80 , so that the sensor carriage  64  is locked in the direction of the double arrow  66 . 
   When the way sensor arrangement  60  is mounted in a gear case, which is (not shown), the arms  70  and  72  rest against the circumferential surface of a shift rail  86  and are bent elastically upward until the latches  74 ,  76  engage in the upper recesses  82 ,  84  of the guide grooves  78 ,  80 . In this assembly state as well as the sensor carriage  64  is locked in the direction of the double arrow  66 . 
   In a subsequent assembly step, the shift rail  86  is displaced in the illustrated case in a longitudinal direction  87  until the arms  70 ,  72  with the latches  74 ,  76  arranged therein engage in a catch recess  88  configured as a peripheral groove. The arms  70 ,  72  rest against the bottom of the catch recess  88 , wherein they assume an intermediate position in which the latches  74 ,  76  are aligned with the guide grooves  78 ,  80  so that the sensor carriage  64  is no longer locked in the direction of the double arrow  66 . 
     FIG. 3  shows a partial cross-sectional view of the sensor housing  62 , the sensor carriage  64  with an elastic arm  70  and the shift rail  86  with the catch recess  88 . As explained above, the arm  70  assumes a lower position  70 ′ in the “as delivered” state, in which the associated latch  74 ′ engages in a lower recess  90  of the guide groove  78 , so that the sensor carriage  64  is locked in the direction perpendicular to the drawing plane. 
   During assembly of this way sensor arrangement, the arm is first bent upward in the position given reference numeral  70 ″ by coming in contact with the outer circumference of the shift rail  86 , wherein the associated latch  74 ″ engages in the upper recess  82  of the guide rail  78 , so that in this assembly state the sensor carriage  64  is in turn locked in the displacement direction  66 . 
   If the arm  70  can drop into the catch recess  88  by displacing the shift rail  86  in the longitudinal direction  87 , the arm is held in a center position by the bottom of the catch recess, in which the latch  74  can be freely displaced in the guide groove  78  and the sensor carriage  64  can be picked up by the shift rail  86  for displacement measuring purposes. 
   REFERENCE NUMERALS  
   
       
         2  way sensor arrangement 
         3  printed circuit board 
         4  sensor housing 
         6  gear case 
         8  cursor tab 
         10  cursor carrier 
         12  sensor carriage 
         14  catch projection 
         16  catch recess 
         18  shift rail 
         20  double arrow 
         22  spring device 
         24  stop device 
         26  stop device 
         28  bracket 
         30  bracket 
         32  bracket 
         34  bracket 
         36  stop surface 
         38  stop surface 
         40  retention projections 
         42  retention recesses 
         44  outer circumference 
         46  arrow 
         48  stop surfaces 
         50  stop surfaces 
         52  retention recesses with transmitting coil 
         54  retention projections 
         56  bottom 
         60  way sensor arrangement 
         62  sensor housing 
         64  sensor carriage 
         66  double arrow 
         68  cursor carrier 
         70  arms 
         70 ′ arms in the lower position 
         70 ″ arms in the upper position 
         72  arms 
         74  latch 
         74 ′ latch (in lower position) 
         74 ″ latch (in upper position) 
         76  latch 
         78  guide groove 
         80  guide groove 
         82  recess 
         84  recess 
         86  shift rail 
         87  longitudinal direction 
         88  catch recess 
         90  recess