Abstract:
A torque sensor system for a transmission and other powertrain components in a motor vehicle includes a receiver and a transmitter. The receiver is operable to induce and detect a signal from the transmitter that is indicative of a torque load on the transmitter. The receiver is cylindrical and has an outer surface with a maximum, constant diameter. The outer surface defines one or more fluid transfer grooves and a docking port for an electrical connection. The fluid transfer groove and the docking port do not extend beyond the maximum outer diameter of the outer surface. Therefore, the receiver is capable of being press-fit within a component and is capable of routing fluid flow. An electrical connector is fed through an access hole and connects with the receiver.

Description:
CROSS-REFERENCE 
     This application claims the benefit of U.S. Provisional Application No. 61/434,595, filed Jan. 20, 2011. The entire contents of the above application are incorporated herein by reference. 
    
    
     FIELD 
     The present disclosure relates to torque sensors, and more particularly to a torque sensor system having an electrical connector that connects with an integral contact pad on a torque sensor receiver. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
     Transmissions and other powertrain components in automotive vehicles are complex mechanisms controlled by hydraulic systems and electronic control modules. In order to provide proper control, it is necessary to have feedback on the operating conditions and performance of the transmission as the transmission operates. For example, transmissions typically include a plurality of sensors that communicate information indicative of the operating state of the transmission to the electronic controller. These sensors take many forms and perform various functions. For example, it is often desirable to determine the torque on a rotating shaft (rotator) relative to a stationary component (stator). Accordingly, a torque sensor is used to measure the torque. Common torque sensors include strain gages, magnetic or optical sensors, and surface acoustic wave (SAW) sensors. These torque sensors each measure various parameters such as local strain, angular displacement, or strained-induced change on an acoustic wave. Typically these torque sensors have two components including what can generally be referred to as a transmitter and a receiver. The receiver is typically coupled to the stator and the transmitter is coupled to the rotator. In the case of magnetic sensors and SAW sensors, a current is induced through the receiver and torque applied on the rotator is transmitted back to the receiver in a form of current, radio signal or magnetic field which is then converted into an estimated torque. 
     However, transmission designs are becoming more compact in order to improve cost, mass, fuel economy, etc. To operate properly, the transmission usually requires supply of pressurized oil to lubricate, cool, or operate systems. One issue related to the above described torque sensors is the ability to package and assemble the torque sensor in current and future transmissions that have compact designs while not impeding pressurized oil flow or other necessary operations of the transmission. 
     While current transmission sensors are useful for their intended purpose, there is room in the art for an improved sensor system for a powertrain component that allows the torque sensor to be packaged in difficult areas of a transmission. 
     SUMMARY 
     A torque sensor system for a transmission and other powertrain components in a motor vehicle is provided. The torque sensor system includes a receiver and a transmitter. The receiver is operable to induce and detect a signal from the transmitter that is indicative of a torque load on the transmitter. The receiver is cylindrical and has an outer surface with a maximum, constant diameter. The outer surface defines one or more fluid transfer grooves and a docking port for an electrical connection. The fluid transfer groove and the docking port do not extend beyond the maximum outer diameter of the outer surface. Therefore, the receiver is capable of being press-fit within a component and is capable of routing fluid flow. An electrical connector is fed through an access hole and connects with the receiver. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a cross section of a portion of an exemplary shaft assembly; 
         FIG. 2  is a cross section perspective view of a portion of an exemplary shaft assembly; 
         FIG. 3  is a perspective view of first side of a component of a torque sensor; 
         FIG. 4  is a perspective view of a second side of the component shown in  FIG. 3 ; 
         FIG. 5  is a side perspective view of a connector; and 
         FIG. 6  is a cross section perspective view of a portion of an exemplary shaft assembly with the component and connector shown in  FIGS. 4 and 5 . 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     With reference to  FIG. 1 , an exemplary shaft or torque-transfer assembly is illustrated and indicated by reference number  10 . In the example provided, the shaft assembly  10  may be part of a torque converter and transmission, however it should be appreciated that various other shafts or members may be employed in various parts of a vehicle powertrain without departing from the scope of the present invention. The shaft assembly  10  defines a linear axis  11 . 
     As part of a torque converter and a transmission, the shaft assembly  10  includes a turbine shaft or rotating member  12 , a stator or housing  14 , and a torque sensor assembly  16 . The turbine shaft  12  is coupled to the turbine (not shown) of a torque converter (not shown) and provides torque to the transmission (not shown). The turbine shaft  12  is rotatable about the axis  11 . The housing  14  is rotationally fixed relative to the turbine shaft  12  and is preferably interconnected to a housing of the transmission (not shown). In alternate configurations, the housing  14  may be a rotating sleeve shaft and the turbine shaft  12  may be a rotationally fixed member. The housing  14  has an inner surface  18  and an outer surface  20 . The inner surface  18  defines a bore or cavity  22  that is coaxial with the axis  11 . The housing  14  includes, in the example provided, a first radially extending fluid passage  24 A and a second radially extending fluid passage  24 B that each communicate between the outer surface  20  of the housing  14  and the bore  22 . The fluid passages  24 A-B are preferably spaced along an axial length of the housing  14 , though the locations of the fluid passages  24 A-B on the outer surface  20  may vary without departing from the scope of the present invention. Additionally, the number of fluid passages  24 A-B may vary without departing from the scope of the present invention. The fluid passages  24 A-B are operable to receive one or more fluid flows of a pressurized hydraulic fluid, such as a transmission oil. A plurality of radial seals  26  are sealingly engaged to the outer surface  20  and to a sleeve (not shown) or other structure that supports the shaft assembly  10 . The radial seals  26  are located axially on either side of the fluid passage  24 B to hydraulically isolate the fluid passage  24 B axially. The fluid passage  24 A may also be sealed using radial seals (not shown) or other seal configurations without departing from the scope of the present invention. Finally, the outer surface  20  of the housing  14  may include various other features, such as gear teeth, apertures, shoulders, flanges, support members, grooves, etc., to engage, support, or interconnect with various other components of the transmission without departing from the scope of the present invention. 
     The rotating shaft  12  is disposed within the bore  22  and is concentric with the housing  14 . The rotating shaft  12  is supported within the bore  22  by bearings (not shown) such that the rotating shaft  12  is operable to rotate about the axis  11  with respect to the housing  14 . The rotating shaft  12  may be solid or have various fluid passages, bores, or other features not specifically shown. 
     As noted above, the rotating shaft  12  transfers torque between, for example, a turbine of a torque converter and a shaft, gear, clutch, or brake located within the transmission. The torque sensor assembly  16  is configured to sense the torque on the rotating shaft  12  at any given time. The torque sensor assembly  16  generally includes a receiver  30  and a transmitter  32 . The torque sensor assembly  16  is, in the example provided, a magneto-elastic toque sensor that measures a magnetic flux. However, it should be appreciated that other types of torque sensor assemblies may be employed, such as a surface acoustic wave (SAW) sensor, a bulk acoustic wave (BAW) sensor, a surface acoustic wave filter, a surface acoustic wave resonator, a surface acoustic wave delay line, a bulk acoustic wave resonator, a strain gage, or an optical sensor. 
     Turning to  FIG. 3  and continued reference to  FIGS. 1 and 2 , the receiver  30  has a cylindrical or tubular body  31  and includes a first end  34 , a second end  36  opposite the first end  34 , an inner surface  38 , and an outer surface  40 . The tubular body  31  is a composite material, such as a plastic. The first and second ends  34  and  36  have openings that communicate with an inner bore  42  defined by the inner surface  38 . The receiver  30  is press-fit within the bore  22  of the housing  14  such that the outer surface  40  of the receiver  30  is in press-fit contact with the inner surface  18  of the housing  14 . The receiver  30  is coaxial with the axis  11 . Accordingly, the shaft  12  extends through the inner bore  42  of the receiver  30 . 
     The outer surface  40  of the receiver  30  defines a plurality of fluid grooves  50  including a first fluid groove  50 A, a second fluid groove  50 B, and a third fluid groove  50 C. The fluid grooves  50 A-C extend parallel to the axis  11 . In the particular example provided, the receiver  30  includes three fluid grooves  50 A-C sized and spaced to communicate with any number and location of fluid passages  24 A and  24 B located in the housing  14 . It should be appreciated that any number of fluid grooves  50  may be included without departing from the scope of the present invention. 
     The fluid grooves  50 A-C are each defined by a bottom surface  52 , side surfaces  54  and  56 , and end surfaces  58  and  60 . Additionally, the fluid grooves  50 A-C have a top surface defined by the inner surface  38  of the housing  14  when the receiver  30  is press-fit within the bore  22 . The fluid grooves  50 A-C extend into the receiver  30  to a predefined depth “d” and width “w” and have a predefined length “L”. Accordingly, each of the fluid grooves  50 A-C may have different depths and widths to accommodate various amounts of fluid flow and different lengths to accommodate the locations of fluid passages  24 A-B, as will be described in further detail below. In the example provided the fluid grooves  50 A-C are grouped together asymmetrically along the circumference of the receiver  30 , though the fluid grooves  50 A-C may be spaced equally circumferentially apart along the outer surface  40 . 
     As noted above, the receiver  30  is sized to be press fitted within the bore  22  of the housing  14 . More specifically, the receiver  30  is inserted within the bore  22  such that either the first end  34  or the second end  36  of the receiver  30  abuts an end or stepped portion of the bore  22 . As the receiver  30  is pressed fitted in the bore  22 , the transmitter  22  deflects which induces a compressive strain that seals the outer surface  40  of the receiver  30  to the inner surface  18  of the housing  14 . The receiver  30  may be held in place by a snap ring (not shown), though various other methods of securing the receiver  30  within the housing  14  may be employed without departing from the scope of the present invention. 
     In the particular example provided, the fluid transfer tube  30  is aligned or oriented with the housing  14  such that the fluid groove  50 B is aligned and communicates with fluid passages  26 A and  26 B. Accordingly, hydraulic fluid or oil is communicated between the fluid passage  24 A and  24 B via the fluid groove  50 B. Therefore, the length “L” of any given fluid groove  50 B is at least equal to the distance between any two fluid ports  24  that communicate with the given fluid groove  50 A-C. It should be appreciated that the fluid flows may communicate in any direction through the fluid grooves  50 A-C without departing from the scope of the present invention. 
     Turning to  FIG. 4 , the receiver  30  further includes a docking port  62  located proximate the first end  34 . The docking port  62  is a recess formed in the outer surface  40  and includes an electrical pad  64 . The electrical pad  64  is substantially planar and includes a plurality of electrical connectors  66 . The electrical connectors  66  communicate with the electronics package or torque measuring circuit (not shown) located within the body  31  of the receiver  30 . The docking port  62  and the electrical connectors  66  do not extend beyond the outer diameter of the outer surface  40 , thereby not interfering with the press-fit engagement between the receiver  30  and the housing  14 . 
     Turning to  FIG. 5 , an electrical connector is indicated by reference number  70 . The electrical connector  70  is selectively connectable to the docking port  62  in order to electrically link the receiver  30  to external controls such as a transmission control module or other control module (not shown) within the transmission. The electrical connector  70  is preferably a spring loaded (pogo-pin style) connector having multiple electrical connectors  72  at a distal end of a substantially cylindrical plug portion  74 . An insulated wire or cable  76  extends from the plug portion  74  and communicates electrical signals from the receiver  30  through the multiple electrical connectors  72  to the external controls of the transmission or powertrain component. An exemplary electrical connector  70  is the Push Pogo Pin-1, made by Solarbotics. However, it should be appreciated that other electrical connectors may be employed. 
     With reference to  FIG. 6 , the electrical connector  70  is disposed within a bore  78  defined by the housing  14 . The bore  78  communicates between an outer surface  80  of the housing  14  and the central bore  22  of the housing  14 . In the example provided, the bore  78  has an axis  83  that intersects the axis  11  at an acute angle. The receiver  30  includes a feature, shown in  FIG. 3 , which contacts a feature (not shown) in the central bore  22  in order to radially orient the receiver  30  within the housing  14  such that the docking port  64  is aligned with the bore  78 . As shown in  FIG. 6 , the bore  78  is sized to receive the plug portion  74  of the electrical connector  70 . 
     During assembly, once the receiver  30  has been press fit within the housing  14 , the electrical connector  70  is inserted into the bore  78  until the electrical connectors  72  mate or contact the electrical pad  64  of the receiver  30 . A radial seal  84  seals the plug portion  74  to the bore  78  in order to prevent fluid leakage out of the housing  14 . In addition, the plug portion  74  may be held in place by a retaining ring  86  that engages a groove  88  formed in the bore  78 . The electrical connector  70  eliminates the need to feed wiring blindly through the bore  78  or any other access hole in the housing  14 . 
     Returning to  FIG. 1 , the transmitter  32  includes one or more magnetoelastic rings secured to the shaft  12  and located within the receiver  30 . A current is induced through the receiver  30  thereby magnetizing the magnetoelastic rings  32 . Where there is no applied torque on the shaft  12 , and therefore the magnetoelastic rings  32 , the magnetic fields of the magnetoelastic rings are contained within the rings. As stress due to torque is applied to the shaft  12  and therefore the rings  32 , the magnetic field twists and is detected by the receiver  30 . The receiver  30  communicates the detected magnetic field values to the controller (not shown). Because the characteristics of the detected magnetic field are proportional to the applied torque on the shaft  12 , the torque on the shaft  12  can be estimated. 
     The torque sensor assembly  16  allows the packaging of the receiver  30  in many previously impossible areas due to the ability of the receiver  30  to not impeded, but rather provide for, hydraulic oil flow through the transmission. In addition, by having a constant outer diameter, the receiver  30  can be easily and simply press-fit into a shaft assembly, thereby reducing assembly costs. Providing an electrical connector to allow blind assembly of a wiring harness to a deeply located multiple contact pad device connected to a torque neasuring circuit also reduces assembly costs and complexity. 
     The description of the invention is merely exemplary in nature and 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.