Abstract:
The end portion of the insulation sheath of a cable is formed into a grommet to promote better mechanical bonding with a vehicle sensor housing that is overmolded onto the cable.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates generally to vehicle sensors.  
       BACKGROUND  
       [0002]     Most motor vehicles include a plethora of sensors and actuators incorporated into the vehicle control systems, such as the anti-lock braking system (A.B.S.), the traction control system (T.C.S.), and the vehicle stability enhancement control system (V.S.E.). Many of the vehicle sensors have housings that are connected to the cable from other components. Regardless, these housings are disposed in the vehicle. The connections between the cable and housings have been known to come loose and become dysfunctional. In current housing-cable connections, very little resistance is provided in preventing cable detachment, because while the housings can be overmolded onto the cable insulation for better mechanical connection, the overmolded sensor housing nonetheless may not always properly adhere to the cable.  
       SUMMARY OF THE INVENTION  
       [0003]     A sensor housing assembly includes a hollow plastic sensor housing and a pressure struded cross-linked electrical cable over at least a portion of which the housing is molded. The portion forms a grommet to promote bonding between the housing and cable.  
         [0004]     The sensor may be a vehicle sensor such as a temperature sensor, pressure sensor, oil condition sensor, magnetic sensor, or other sensor, and the housing may be disposed in a vehicle.  
         [0005]     In a preferred embodiment the cable can include at least one electrical conductor inside an electrically insulative sheath, with the sheath being formed with the grommet. The grommet may include plural ribs, with adjacent ribs being separated by a groove. The ribs and grooves can have rectilinear cross-sections and can be oriented perpendicularly to a long axis of the cable and extend completely around the circumference of the cable.  
         [0006]     In another aspect, a method for engaging a cable with a plastic housing includes forming at least one circumferential rib and at least one circumferential groove in an end segment of the cable, and then disposing the cable in a mold. The method then includes overmolding the housing onto at least the segment using the mold, whereby the segment contour promotes engagement of the housing and cable.  
         [0007]     In still another aspect, a vehicle sensor includes a sensor housing, at least one electrical terminal in the housing, and at least one cable electrically connected to the terminal. The housing is overmolded on the cable. Means are formed on the cable for promoting engagement of the cable with the housing.  
         [0008]     The details of the present invention, both as to its structure and operation, can best be understood in reference to the accompanying drawings, in which like reference numerals refer to like parts, and in which: 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a cross-sectional view of the present cable engaged with a sensor housing that has been overmolded onto it;  
         [0010]      FIG. 2  is a side view of the housing end of the cable, showing the pre-formed grommet; and  
         [0011]      FIG. 3  is a flow chart of the method for making the sensor housing with cable. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0012]     Referring initially to  FIG. 1 , a system is shown, generally designated  10 , that includes a hollow, plastic sensor housing  12  that is overmolded onto an electrical cable  14 , such as a pressure struded cross-linked electrical cable. The cable  14  includes at least one (and usually two) electrical conductors inside an electrically insulative sheath, as further discussed below.  
         [0013]     The sensor in the housing  12  can perform a number of different functions. For instance, the sensor may be a temperature sensor, pressure sensor, oil condition sensor, magnetic sensor, or other sensor. The function of the sensor, however, is irrelevant to the invention at hand.  
         [0014]     As shown in  FIG. 1 , one or more electrical terminals  16  are mounted in the housing  12 , and may be connected to a first vehicle component  17 , such as, e.g., a corresponding electrical socket on a sensor, or other electrical interface. It is to be understood that the terminal or terminals  16  are electrically connected to corresponding conductors in the cable  14 . The cable  14  is electrically connected in turn to a second vehicle component  18 , such as, e.g., a vehicle onboard computer or ECM.  FIG. 1  shows that if desired, a rubber of plastic sleeve  19  with axially-spaced outwardly protruding radial lips can be sandwiched between the cable  14  and housing  12 .  
         [0015]     Now referring to  FIG. 2 , the electrical cable  14  has a housing end segment  20  that, like the remainder of the outer cylindrical surface of the cable, is covered by an electrically insulative sheath  22 . However, at the housing end  20  the sheath  22  is formed with a grommet that is established by alternating grooves  24  and ribs  26 , each of which preferably has a rectilinear cross-section and each of which preferably extends completely around the circumference of the cable  14 . The ribs  26  and grooves  24  preferably are oriented perpendicularly to the long axis of the cable as shown. The grooves  24  and ribs  26  are made integrally with the sheath  22  as set forth further below. One or more electrical conductors  29  protrude from the end of the sheath  22  as shown.  
         [0016]     Now referring to  FIG. 3 , the procedure for mutating the sheath  22  to have the grommet configuration shown in  FIGS. 1 and 2  can be seen. Commencing at block  28 , the cable is received without the grommet and preferably with a minimal wall thickness. At block  30 , the grommet is formed. In one embodiment this can be done by placing the housing end  20  of the electrical cable  14  in a heat treatment fixture clamp, which has the groove/rib structure formed on it. This clamp is then closed and heated, deforming the sheath  22  to assume the configuration of the clamp, i.e., to have the grommet impressed on it. An alternative method of forming the grommet in the electrical cable  14  is to cut the grooves  24  into the sheath  22  by hand or by machine. In either case, it will be appreciated that the grommet is formed integrally in the sheath  22 .  
         [0017]     Once the grommet is formed, at block  32  the cable  14  is positioned in a housing mold and the hollow, plastic sensor housing  12  is overmolded onto the housing end  20  of the sheath  22 , with the conductors  29  of the cable  14  in electrical engagement with the terminals  16  of the housing  12 . The material that is overmolded onto the sheath  22  flows into the grooves  24 , providing improved engagement of the cable  14  with housing  12 , compared to cables without the present grommet.  
         [0018]     It is to be understood that the current figure shows only three grooves  24  and three ribs  26 , more grooves and ribs (or less) can be formed.  
         [0019]     While the particular SYSTEM AND METHOD FOR PREFORMING CABLE FOR PROMOTING ADHESION TO OVERMOLDED SENSOR BODY as herein shown and described in detail is fully capable of attaining the above-described objects of the invention, it is to be understood that it is the presently preferred embodiment of the present invention and is thus representative of the subject matter which is broadly contemplated by the present invention, that the scope of the present invention fully encompasses other embodiments which may become obvious to those skilled in the art, and that the scope of the present invention is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more”. It is not necessary for a device or method to address each and every problem sought to be solved by the present invention, for it to be encompassed by the present claims. Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. Absent express definitions herein, claim terms are to be given all ordinary and accustomed meanings that are not irreconcilable with the present specification and file history.