Abstract:
Attachment device for a data sensor for a bearing on which an encoding element is connected to a turning race that is separated by rolling elements from a fixed race, the sensor being mounted on a support that is immobile relative to the fixed race. The support has at least a first element and a second element joined together. The first element immobilizes the support relative to the fixed race, and the second element integrates functions of guiding and immobilizing the sensor on the support.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to a device for attaching a data sensor and, more particularly, to a device for attaching a fixed, non-contacting data sensor opposite a bearing equipped with an encoding element capable of being read by the sensor. 
     Publications FR 2 703 740, FR 2 730 283, and FR 2 740 186 describe different supports for a fixed sensor in the immediate vicinity of a fixed race of a bearing. Such supports are generally annular and include a guideway on which the sensor is mounted and held by an elastic immobilization means. 
     As can be seen in various documents, the described bearing assemblies involve a variety of designs for the data sensor supports, which may be attached to one or another of the bearing races, depending on whether the turning race is the outer or the inner race. The supports may also be clamped between the fixed race and a bearing seat mounting element or may even be adapted to an armature on the bearing seal. 
     However, such sensor supports require the design and specification of special tooling in order to make a different support for each possible type of application, which results in significant cost increases. Additionally, there is a need for a device that provides an easy immobilization of the sensor on the support, a device which is also simple and economical to make. 
     The foregoing illustrates limitations known to exist in present devices and methods. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter. 
     SUMMARY OF THE INVENTION 
     In one aspect of the invention, this is accomplished by providing an attachment device for mounting a sensor in proximity to a bearing on which an encoding element is connected to a rotating race of the bearing that is separated by rolling elements from a fixed race of the bearing. The attachment device comprises a support that is adapted for mounting in proximity to the bearing so to be immobile relative to the fixed race. The support comprises at least a first element and a second element joined together. The first element is configured to immobilize the support relative to the fixed race, and the second element is configured to integrate functions of guiding and immobilizing the sensor on the support. 
     The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures. 
    
    
     BRIEF DESCRIPTION OF THE DRAWING FIGURES 
     FIG. 1 is a cross sectional view of a support illustrating an embodiment of the present invention, mounted on a hub assembly of an automobile drive wheel; 
     FIG. 2 is a perspective view of the support of FIG. 1, illustrating an embodiment of the present invention permitting axial mounting of a sensor; 
     FIG. 3 is a perspective view of a first support element of the support of FIG. 1; 
     FIG. 4 is a perspective view of a second support element of the support of FIG. 1; 
     FIG. 5 is a side view of the second element of FIG. 4; 
     FIG. 6 is a perspective view of a support illustrating a second embodiment of the present invention permitting radial mounting of a sensor, mounted on portions of a hub assembly of an automobile wheel; and 
     FIG. 7 is a perspective view of a support illustrating a third embodiment of the present invention permitting mounting of the support over a bearing with a fixed outer race. 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 illustrates wheel hub assembly  1  in which roller bearing  2  is attached by securing it, using nut  3 , to the shoulder of steering knuckle  4 . Roller bearing  2  may be a standard size and consists of fixed race  5  and turning race  6 , separated by rolling elements  7 . It is kept watertight by means of seal  8 . Turning race  6  is equipped with magnetic encoding device  9  mounted, for example, by bonding, whose rotation is detected by fixed sensor  10  held at a given air gap from the surface of encoding device  9  by support  11  mounted on fixed race  5 . 
     Support  11 , illustrated in FIG. 2, consists of a first element  11   a  and a second element  11   b,  rigidly attached to one another by a process such as spot welding, for example. Of course, in alternative embodiments, first and second elements  11   a  and  11   b  may also be joined together with an adhesive or by mechanical means such as clips or rivets. 
     First element  11   a , illustrated separately in FIG. 3, comprises a generally annular central disk  14 , equipped with collar  15  at its center. Preferably, central disk  14  has an area whose surface configuration is capable of fitting together with a rim on seal  8  when support  11  is banded onto fixed race  5 , thereby ensuring dynamic sealing of the bearing. First element  11   a  also includes peripheral annular part  16  that extends radially outward on a plane shifted from that of central disk  14 , and is equipped with tabs  18  designed to be welded or otherwise attached to second element  11   b.    
     Second element  11   b , illustrated separately in FIGS. 4 and 5, consists of armature  20 , approximately parallelepipedal in form, designed to enclose sensor  10 . This armature  20  includes, on one face, window  20   a  through the free end of which sensor  10  is inserted, and lateral edges  20   b  which act as guide rails that match grooves cut along lateral edges of sensor  10 . Armature  20  also includes, on the face opposite that of window  20   a , two flexible tabs  21  equipped with boss  21   a  that extend towards the interior of armature  20  where they fit into a cavity provided in sensor  10  and serve to fix it in position. In order to facilitate insertion of sensor  10  into armature  20 , the end of flexible tabs  21  is curved outward, and the end of guide rails  20   b  is beveled so as to guide sensor  10  along the axis of armature  20 . 
     Armature  20  is held rigid by small bridge  13  that extends from the end of guide rails  20   b , perpendicular to the edge of armature  20 , and is designed to be welded or otherwise attached to tabs  18  on first element  11   a.  Armature  20  also includes side tabs  19  positioned on a plane perpendicular to the plane of small bridge  13 , and permitting second element  11   b  to be attached to first element  11   a  in different directions in the embodiment variants of the invention. 
     As illustrated in FIG. 1, support  11 , obtained by assembling first and second elements  11   a  and  11   b  together, permits sensor  10  to be kept in precise position relative to encoding device  9  by providing a first element  11   a  with high rigidity, and also optimizes the ease of insertion and securing of sensor  10  through support  11  by providing second element  11   b  equipped with good flexibility. Thus, first element  11   a  may be advantageously made at low cost by stamping it from a steel plate with relatively low mechanical properties, the connecting flange between central disk  14  and annular part  16  providing great rigidity to first element  11   a.  Second element  11   b  may be advantageously obtained by the process of cutting and folding a steel plate whose thickness and mechanical properties are suited to obtaining a good spring-like effect from tabs  21 . 
     By maintaining the same second element  11   b  from FIG.  4  and therefore the same standard size sensor  10 , for example, the attachment device according to the invention also makes it possible to make different supports  11  adapted for radial or axial mounting of sensor  10 . Thus, as shown in FIG. 6, illustrating a second embodiment of the attachment device according to the present invention, second element  11   b  may also be mounted perpendicularly with respect to first element  11   a  by means of side tabs  19  so as to permit radial mounting of sensor  10 . 
     In a third embodiment of the attachment device according to the present invention, shown in FIG. 7, the same second element  11   b  may also be mounted on first element  11   a  which is adapted so as to be mounted on outer fixed race  5  of a bearing. The attachment device according to the invention therefore permits a quick and inexpensive adaptation of the support to different needs relating to various assemblies. In addition, by making the sensor support on the basis of a first element that immobilizes the support on the fixed race and a second element that guides and immobilizes the sensor, it is possible to optimize the thickness and choice of materials depending on the specific needs of each of the elements, and hence to reduce the cost. 
     The invention is, of course, in no way limited to the illustrated and described embodiment, which is given by way of example only. In particular, the sensor support may be attached to any element, immobile relative to the fixed race and located near the sensor.