Patent Abstract:
A wheel speed sensor latch for securing a wheel speed sensor to a bearing cap of a vehicle speed sensing assembly. The latch includes a main body having a collar section adapted for receiving the wheel speed sensor therethrough. The latch further includes a pair of bifurcated legs extending from the main body. The pair of bifurcated legs being engageable with a pair of latching members formed on the bearing cap such that the pair of latching members and the pair of bifurcated legs cooperate to secure the wheel speed sensor on the bearing cap.

Full Description:
FIELD OF THE INVENTION 
     The present invention generally relates to a speed sensing assembly and, more particularly, to a sensor latch for ensuring proper positioning of a speed sensor within a speed sensing assembly. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     Speed sensing assemblies, which measure the rate of rotation of a vehicle wheel, are critical components of vehicle anti-lock braking systems, traction control systems, and the like. Speed sensing assemblies may be made as a one-piece assembly, which consists of a rotor which is mounted for rotation with the vehicle wheel and a stator that is generally mounted to the structure of the vehicle. The stator includes a bearing assembly which is adapted to rotatably receive the rotor therein. The stator assembly further includes a wheel speed sensing head or sensor which cooperates with the rotor to generate a pulsed output signal representative of wheel speed. It is imperative that the sensor be maintained in proper positioning relative to the rotor in order to ensure proper operation of the wheel speed sensor. 
     Frequently, speed sensing assemblies are manufactured and assembled at a location apart from the final assembly of the vehicle. This method allows the various mechanical and electrical connections to be tested prior to installation on the vehicle. However, occasionally it becomes necessary to assemble the various parts of the speed sensing assembly during the final assembly of the vehicle. For instance, it has recently become necessary to install the sensing head of the speed sensing assembly following installation of the main body within the vehicle. As a result, it has become more difficult to ensure that the sensor is properly seated within the speed sensor assembly to maintain reliable output of the pulsed signal. 
     Accordingly, there is a need in the relevant art to provide a method of ensuring proper installation of the sensor within the main body of the speed sensing assembly. Furthermore, there exists a need in the relevant art to provide a latching member which signals a positive connection with the main body of the speed sensor assembly. Still further, there exists a need in the relevant art to provide a positive latching member for a speed sensing assembly that overcomes the deficiencies of the prior art. 
     In accordance with the broad teachings of this invention, a positive sensor latch having an advantageous construction and method of assembly is provided. The latch includes a main body having a collar section adapted for receiving the wheel speed sensor therethrough. The latch further includes a pair of bifurcated legs extending from the main body. The pair of bifurcated legs being engageable with a pair of latching members formed on the bearing cap such that the pair of latching members and the pair of bifurcated legs cooperate to secure the wheel speed sensor on the bearing cap. 
     Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are intended for purposes of illustration only. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
     FIG. 1 is an exploded perspective view of a vehicle bearing assembly employing a sensor retaining latch according to the principles of the present invention; 
     FIG. 2 is a perspective view of the sensor retaining latch according to the principles of the present invention; and 
     FIG. 3 is an enlarged perspective view of the vehicle bearing assembly illustrating the sensor retaining latch in a latched position. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following description of the preferred embodiment is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
     Referring now to the drawings, a vehicle bearing assembly  10  is shown having a solid rotating spindle or shaft  11  surrounded by a cylindrical hub  12 . Cylindrical hub  12  is fixed to the vehicle suspension via a plurality of threaded apertures  14  and corresponding fasteners (not shown). Vehicle bearing assembly  10  further includes an integrated wheel speed sensor assembly  16  having a wheel speed sensor  18  (FIG.  1 ), an optional spring clip  20 , a tone wheel  22  fixed to spindle  11  for rotation therewith, and a bearing cap  24 . Bearing cap  24  is generally dome shaped and includes an integrally-molded, sensor-receiving cavity  26  adapted to receive wheel speed sensor  18  therein. Sensor-receiving cavity  26  is generally cylindrical in shape and includes a pair of external slots  28  formed orthogonally to a longitudinal axis A—A of sensor-receiving cavity  26 . Each of the pair of external slots  28  includes an elongated hole  30  (only one shown), which enables spring clip  20  to retain wheel speed sensor  18  within sensor-receiving cavity  26 , which will be described below. 
     As best seen in FIG. 1, wheel speed sensor  18  includes a sensor probe  32 , an O-ring seal  34 , and a pair of retaining slots  36  (only one shown) formed on opposing sides of wheel speed sensor  18 . During installation, a pair of retaining legs  38  of optional spring clip  20  extend through elongated holes  30  and are received within the pair of retaining slots  36  of wheel speed sensor  18  when wheel speed sensor  18  is disposed within sensor-receiving cavity  26 . 
     Tone wheel  22  cooperates with wheel speed sensor  18  in a manner conventional in the art to produce an output signal representative of the wheel speed. A cable  40  interconnects wheel speed sensor  18  with a control device (not shown) for delivering the wheel speed data to the control device (i.e. vehicle computer), which is then capable of determining wheel slippage for use in anti-lock braking systems, traction control systems, and the like. 
     Recently, it has been found that spring clip  20  may not provide feedback to an installer of a proper positioning of wheel speed sensor  18  relative to sensor-receiving cavity  26  or tone wheel  22 . That is, it has been found that in known designs wheel speed sensor  18  may be partially disposed within sensor-receiving cavity  26 , however, spring clip  20  is locked around a lower section of wheel speed sensor  18  than retaining slots  36  thereby appearing to be properly positioned and seated. Conversely, wheel speed sensor  18  may be fully disposed within sensor-receiving cavity  26 , yet not sufficiently retained by spring clip  20 . 
     On the other hand, wheel speed sensor  18  may be sufficiently retained by spring clip  20 , but improperly positioned in sensor-receiving cavity  26 . Accordingly, sensor retaining latch  42  is disposed about wheel speed sensor  18  so as to effect a positive latch condition. That is, sensor retaining latch  42  insures wheel speed sensor  18  is properly positioned and seated by preventing latching of sensor retaining latch  42  until wheel speed sensor  18  is properly positioned and seated, thereby providing positive feedback to an installer that wheel speed sensor  18  has been installed properly. 
     Sensor retaining latch  42  includes a base section  44  and an upwardly-extending collar section  46 . Sensor retaining latch  42  further includes a pair of downwardly-extending bifurcated legs  48  and a pair of downwardly-extending shoulders  50 . Preferably, sensor retaining latch  42  is made of a plastic material. More preferably, sensor retaining latch  42  is made of a plastic material containing approximately 15% glass for improved strength and flex capabilities. Sensor retaining latch  42  may be manufactured simply employing conventional injection molding techniques. To facilitate inspection and confirmation of installation, sensor retaining latch  42  is preferably yellow or any other bright color. 
     Base section  44  of sensor retaining latch  42  and upwardly-extending collar section  46  cooperate to define a through bore sufficiently sized to receive wheel speed sensor  18  therethrough. Specifically, collar section  46  is generally cylindrical in shape having a pair of opposing flat sections  52 . Flat sections  52  of collar section  46  are sized to cooperate with a corresponding pair of opposing flat sections  54  on wheel speed sensor  18 . Such flat sections  52 ,  54  prevent rotation of sensor retaining latch  42  and wheel speed sensor  18  relative to each other. 
     As seen in the figures, downwardly-extending bifurcated legs  48  engage a pair of suitably sized latch nubs  58  extending from a lower exterior section of sensor-receiving cavity  26 . Specifically, bifurcated legs  48  each include a pair of side members  60  extending from base section  44 . Side members  60  terminate into an interconnecting member  62 . Interconnecting member  62  includes a generally flat top surface  64  for engaging a lower surface  66  of latch nub  58 . Likewise, interconnecting member  62  further includes a chamfered or otherwise inclined or tapered edge  68 , which is adapted to ride along a tapered top surface  70  of latch nub  58  during an engaging motion. When fastened, each latch nub  58  extends between side members  60  and engages generally flat top surface  64  of interconnecting member  62 . 
     As described above, bifurcated legs  48  are adapted to ride over latch nubs  58  during installation and, thus, must flex a sufficient distance to enable such passing. However, it should be appreciated that bifurcated legs  48  must also maintain sufficient bias to maintain a latch position once engaged. 
     During installation, wheel speed sensor  18  is inserted within sensor-receiving cavity  26  such that O-ring seal  34  of wheel speed sensor  18  is firmly seated within sensor-receiving cavity  26 . The pair of retaining slots  36  of wheel speed sensor  18  are aligned with the pair of external slots  28  and elongated holes  30  of sensor-receiving cavity  26 . Spring clip  20  may optionally be engaged with wheel speed sensor  18  such that retaining legs  38  of spring clip  20  extend through elongated holes  30  and lock within the pair of retaining slots  36  of wheel speed sensor. Sensor retaining latch  42  is then engaged with latch nubs  58 . Specifically, sensor retaining latch  42  is pressed downward such that tapered edge  68  of bifurcated legs  48  rides along tapered top surface  70  of latch nub  58 . This movement forces bifurcated legs  48  to flex outwardly until generally flat top surface  64  engages lower surface  66  of latch nub  58  and flexes inwardly to an engaged position. This latching motion produces a click or similar positive locking feedback to the installer to insure proper locking of wheel speed sensor  18  within sensor-receiving cavity  26 . 
     It has been found that the sensor retaining latch of the present invention provides simple and reliable latching of the wheel speed sensor within the sensor-receiving cavity even when only one bifurcated leg is engaged with the corresponding latch nub. Therefore, should the installer inadvertently latch only one side of the sensor retaining latch, the wheel speed sensor will remain in proper position for determining wheel speed and, thus, permits optimal signal generation. 
     The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Technology Classification (CPC): 6