Abstract:
A terminal for a resolver that operates in a high temperature environment is presented. The terminal includes a terminal block having a through groove. The through groove provides a resistive welder with access to flat terminals mounted on the terminal block. Resistive welding the stator coil wire of the resolver to the flat terminals is less complicated than soldering the stator coil wire to the flat terminals and provides a connection more able to withstand high temperatures.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of Japanese Patent Application No. 2002-279578 entitled “Resolver I/O Terminal Structure and Method of Connecting Resolver Thereby,” naming the same inventors, filed on Sep. 25, 2002, claiming priority benefits under 35 USC § 119. 
   FIELD OF THE INVENTION 
   The present invention relates to resolvers. More particularly, the present invention relates to terminals on resolvers that may be used at high temperatures. 
   BACKGROUND OF THE INVENTION 
   Resolvers are electrical devices that are most often used as angle measurement transducers. Various types of resolvers have been developed in order to reduce their size and increase their performance. 
   One type of resolver includes insulating members. To connect to the resolver, pins are included in an extension part of an insulating member. The wires of the stator coil of the resolver connect to the pins, as do the lead wires or an electrical connector on the resolver. An example of such a resolver is disclosed in Japanese Unexamined Patent Application Publication H 10-309067. Making the resolver smaller reduces the amount of insulating material. But because the extension part with the pins is integrated into the insulating member a smaller amount of insulating material renders the extension part more susceptible to breakage when making an electrical connection to the resolver. 
   Other types of resolvers include connectors with male or female connector pins that are integrated with an insulating cover of the resolver. An example of such a resolver is disclosed in Japanese Unexamined Patent Application Publication 2001-330472. The integration of the pins with the insulating cover makes the connectors mechanically stronger. As such, external connectors may be attached and removed from the resolver with ease. The wires of the stator coils connect to the pins. But because the pins are integrated with insulating cover, reducing the size of such resolvers is difficult. 
   Yet other types of resolvers have terminal holders within notched parts on the outer periphery of a ring-shaped stator. An example of such a resolver is disclosed in Japanese Unexamined Patent Application Publication 2001-56237. The lead lines to the resolver are along the axial direction of the stator. For these types of resolver, the various corners on the resolver are flat, resulting in a thinner structure with a smaller diameter. 
   Further, all the above-described resolvers operated at normal temperatures and could not withstand high temperatures. An example of a high temperature resolver is shown in FIG.  8 . The stator of the resolver includes a stator core  100  comprising multiple layers of plates. Stator magnetic poles  104  protrude from the stator core  100  towards the center of the yoke of the resolver and have multiple stator magnetic pole teeth  103 . The wires of the stator coils (not shown) wrap around the stator magnetic poles  104 . Two insulating members  101 ,  107  are on either side of the stator core  100 . The periphery of the stator core  100  includes protrusion parts  102 , which in turn include grooves  108  to hold the lead wires  111 . The grooves  108  also include terminal plates  105 . 
     FIG. 9  is a diagram illustrating a terminal plate  105 . The bottom part of the terminal plate  105  is rooted in the groove  108  and has a rim-shaped weld part  120  at the top of the terminal plate  105 . The weld part  120  is bent and has an end of stator coil wire  130  attached to it by resistance welding or high-temperature soldering. The stator coil wire  130  is also wrapped around the top part of the terminal plate  105 . 
     FIG. 10  is a diagram illustrating a lead wire  111 . The lead wire  111  has a core  109  and a covering  106 . Some of the core  109  may be exposed at the tip of the lead wire  111  by means of a mechanical or chemical process. Returning to  FIG. 9 , the core  109  is wrapped under the weld part  120  of the terminal plate  105 . 
   The resolver of  FIG. 8 , however, is hard to miniaturize and manufacture through automation. For operation at high temperature, the insulation on the stator coil wires  130  is highly durable, for example polyamideimide insulation. The connections require resistive welding or high-temperature soldering but the weld part  120  must be large enough to accommodate the electrode of the resistive welder. Also, as the terminal plates  105  are in the grooves  108  during welding or soldering, it is difficult to reduce the size of terminal plates  105 . 
   Additional problem with miniaturizing the resolver of  FIG. 8  include the removal of insulation on the stator coil wires  130  in order to perform high-temperature soldering. The mechanical or chemical method for removing the insulation may affect the reliability of the resolver. Also, the automatic winding equipment for winding the stator coil wires  130  on such a resolver may be complicated. 
   SUMMARY 
   A terminal for a resolver is described below to address the need for a sturdy connector for resolvers that operate at high-temperatures. One aspect of the invention is a terminal that includes a terminal block having a top side and a bottom side. The terminal block has a lengthwise open through groove between the top side and the bottom side. The terminal also includes at least one flat terminal disposed widthwise on the bottom side of the terminal block and traversing the through groove. Each flat terminal of the at least one flat terminal has a top side adjacent the through groove and a bottom side comprising a weld part for retaining stator coil wire of the resolver. In this manner the stator coil wire may be welded to the flat terminal by contacting a first electrode of a resistive welder to the top side of the flat terminal via the through groove and contacting a second electrode of the resistive welder to the weld part. 
   Another aspect of the invention is a terminal that includes a terminal block and means for connecting a stator coil wire to the terminal by welding. The means for connecting the stator coil wire is attached to the terminal block. The terminal also includes means for connecting a lead line to the terminal. The means for connecting the lead line is attached to the terminal block and is in electrical communication with the means for connecting the stator coil wire. 
   Yet another aspect of the invention is a resolver that includes the combination of a stator core, at least one stator coil, a terminal block, and at least one flat terminal. The at least one stator coil includes stator coil wires wound on the stator core. The terminal block has a top side and a bottom side and a lengthwise open through groove between the top side and the bottom side. The at least one flat terminal is disposed widthwise on the bottom side of the terminal block and traverses the through groove. Each flat terminal of the at least one flat terminal has a top side adjacent the through groove and a bottom side comprising a weld part for retaining the stator coil wire. In this manner the stator coil wire is welded to the flat terminal by contacting a first electrode of a resistive welder to the top side of the flat terminal via the through groove and contacting a second electrode of the resistive welder to the weld part. 
   The foregoing and other features and advantages of preferred embodiments will be more readily apparent from the following detailed description, which proceeds with reference to the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a diagram showing a preferred embodiment of a stator assembly of a resolver; 
       FIG. 2  is an underside view of the stator assembly  1  of  FIG. 1 ; 
       FIG. 3  are views of the structure of the terminal blocks of  FIG. 1 ; 
       FIG. 4  is a diagram showing a cross section of a part of the stator assembly of  FIG. 1 ; 
       FIG. 5  is a diagram showing another cross section of a part of the stator assembly of  FIG. 1 ; 
       FIG. 6  is a diagram of a flat terminal; 
       FIG. 7  is a diagram illustrating another preferred embodiment of the stator assembly of  FIG. 1 ; 
       FIG. 8  is a diagram illustrating an example of a high temperature resolver; 
       FIG. 9  is a diagram illustrating a terminal plate; and 
       FIG. 10  is a diagram illustrating a lead wire. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIG. 1  is a diagram showing a preferred embodiment of a stator assembly  1  of a resolver. The stator assembly has a stator core  2  comprising multiple stacked plates with stator magnetic poles  15 . The stator magnetic poles  15  have multiple stator magnet pole teeth  14  directed towards a yoke part (not shown) of the resolver. Stator coil wires (not shown) wind around the stator magnetic poles  15  and may be insulated by a material that can withstand high temperatures, such as polyamideimide. 
   On either axial side of the stator core  2  are insulating members  5 ,  6  which in turn have covers  3 ,  7  on their outsides. The insulating members  5 ,  6  have rim parts  16 ,  18 , which match the stator magnetic pole teeth  14 . The insulating members  5 ,  6  also have protrusions  44 ,  46 , which respectively fit into holes  43 ,  45  in the covers  3 ,  7 . The insulating members  5 ,  6  and covers  3 ,  7  may be made of a polymer, such as polybutylene teraphtlalate. 
   The stator assembly  1  also includes a terminal block  8  that mates with indentations  12  in a protrusion  11  of the stator core  2 . The tips  13  of the protrusions are deformable to align with the outer periphery of the stator assembly  1  when terminal block  8  is mated with the protrusion  11 . The lower insulating member  6  has a protrusion  19 . The terminal block  8  fits into a notched part  27  of the protrusion  19 . The lower insulating member  6  also has through holes  26 . Also, the lower cover  3  has a protrusion  21  with an indentation  28  that accepts the terminal block  8 . 
   The terminal block  8  includes a protrusion part  24  and a rim part  25 . The protrusion part  24  mates with the protrusion part  19  of the lower insulating member  6  by means of the through holes  26 . Similarly, the rim part  25  mates with the upper insulating member  5  and contacts the protrusion part  11  of the stator core  2 . The terminal block  8  also includes fastening protrusions  22  on either side that fit into holes  47  on the upper cover  7 . The terminal block may be made of a material that is a strong insulator and can withstand high temperatures, such as Teflon®. Alternatively, the structure of the protrusion part  19  of the lower insulating member  6  may be fabricated on the upper insulating member  5 . Likewise, the structures on the upper  7  and lower  3  covers may be interchanged, with a similar inversion of the rim  25  and protrusion  24  part of the terminal block  8 . 
   During assembly, the terminal block  8  fits into the indentation part  12  of the stator core  2 . The mating parts  16 ,  18  of the lower  6  and upper  5  insulating members are inserted into the coil wire part  17  of the stator core  2 . The rim part  16  aligns with the magnetic pole teeth  14 . The protrusion parts  44  of the upper insulating member  5  fit into the holes  43  of the upper cover  7 , and the protrusion pats 46 of the lower insulating member  6  fit into the holes  45  of the lower cover  3 . 
     FIG. 2  is an underside view of the stator assembly  1  of FIG.  1 .  FIG. 2  shows the bottom insulating member  6 , the stator core  2 , and the terminal block  8 . When assembled, the rim part  25  of the terminal block  8  makes contact with the upper insulating member  5  and is held in place by the tips  13  of the protrusion part  11  of the stator core  2 . The protrusion parts  24  of the terminal block  8  fit through the holes  26  on the lower insulating member  6 . 
     FIG. 3  are views of the structure of the terminal blocks  8  of FIG.  1 . The top surface of the terminal block  8  includes an indentation having multiple fastening grooves  32 , through holes  31 , and a through groove  33 . The indentation also includes protrusion parts  22 , which are higher than the top surface of the terminal block  8  and fit into holes  47  on the upper cover  7  to secure the terminal block to the upper cover  7  upon assembly. The through groove  33  is between through holes  31  and fastening grooves  32 , and extends to the bottom of the terminal block  8 . The through holes  31  are aligned with the fastening grooves  32  on either side of the through groove  33 . 
   Multiple pin parts  29  of flat terminals  10  pass through the through holes  31 . The lead lines  9  have connection terminals  30  at their ends. The connection terminals  30  are welded to the pin parts  29  to connect the lead lines  9  to the stator assembly  1 . The lead lines  9  sit in the fastening grooves  32 . 
   The bottom surface of the terminal block  8  also has an indentation as shown in FIG.  3 . The width W 1  and depth D 1  of the bottom surface are approximately the same as the width W 2  and depth D 2  of the indentation part  12  of the stator core  2  as shown in FIG.  1 . The indentation includes the through groove  33  from the top surface of the terminal block  8  and two rows of structures either side of the through groove  33 . One row of structures includes alternating fastening pins  34  and anchor posts  41 . The other row includes the through holes  31  from the top surface of the terminal block  8  alternating with slack pins  36 . The bottom surface of the terminal block  8  also includes the protrusion parts  24  that fit through the holes  26  on the lower insulating member  6  and are parallel to the slack pins  36 . 
   Flat terminals  10  traverse the through groove  33 . The top sides of the flat terminals  10  are adjacent the through groove  33 . Each flat terminal has a hole  39  that accepts an anchor post  41  on the indentation of the bottom surface of the terminal block  8 . Each flat terminal also has a weld part  38  on the bottom side of the flat terminal  10  and a pin part  29 . The pin parts  29  pass through the though holes  31  from the bottom surface of the terminal block  8  to emerge from the top surface. 
   Stator coil wire is connected to the terminal block  8  by running the tip  35  of the stator coil wire past the slack pin  36 , through the weld part  36 , and around the fastening pin  34 . The tip  35  is wrapped around the fastening pin  34 , which preferably has an essentially rectangular core section to secure the stator coil wire and is at an angle to the flat terminal  10 . The slack pins  36  preferably have notches near their bases  20  so as to facilitate bending. The stator coil wire that passes through the gaps of the weld parts  38  are subject to resistive welding. 
   FIG.  4  and  FIG. 5  are diagrams showing cross sections of a part of the stator assembly  1  of FIG.  1 . The terminal block  8  fits in the indentation part  12  of the stator core  2  where the rim part  25  of the terminal block  8  is in contact with the protrusion part  11  of the stator core  2 . The top insulating member  5  is in contact with the protrusion part  20  of the top cover  7  and the surrounding standing wall  7   a  of the top cover  7 . The protrusion parts  24  of the terminal block  8  fit through the holes  26  in the lower insulating member  6 . The lower insulating member  6  is in contact with the lower cover  3  and its surrounding standing wall  3   a.    
     FIG. 6  is a diagram of a flat terminal  10 . The flat terminals  10  may be composed of a material which may be composed of a material that may be resistively welded or arc welded, such as phosphor copper. The flat terminal  10  has a pin part  29  that is bent at approximately 90 degrees to the terminal part  40  of the flat terminal  10 . The terminal part  40  has a hole  39 , opposite the pin part  29 , that accepts the anchor posts  41  of the terminal block  8 . The weld part  38  is on the face of the flat terminal  10  that is opposite the direction of the pin part  29 . The weld part  38  defines a space with respect to the terminal part  40  through which the tip  35  of a stator coil wire passes. The tip  35  is resistively welded to the weld part  38 . 
     FIG. 7  is a diagram illustrating another preferred embodiment of the stator assembly  1  of FIG.  1 . In  FIG. 7 , the terminal block  8  is divided into two parts along the plane G of  FIG. 3 , i.e. the part above plane G is in the protrusion  81  of the upper insulating member  5 , and the part below plane G is in the protrusion  80  of the lower insulating member  6 . The protrusion  81  is on the periphery of the upper insulating member  5  and includes the through holes  31  and the through groove  33 . Also, the protrusion  81  includes the grooves  32  for the lead lines  9 . Protrusion parts  50  on to terminal block  8  are on either side of the through groove  33  where the protrusion  81  contacts the stator core  2 . 
   The lower insulating member  6  has a protrusion  80  on its outer periphery. The protrusion  80  has an indentation sunk into the side opposite to the stator core. The indentation includes multiple through holes  31  and the through groove  33 . On one side of the through groove  33  are anchor posts  41 , and on the other side of the through groove  33  are slack pins  36  alternating with the through holes  31 . This may be also seen from  FIG. 3   b  as described above. The slack pins  36  may include notches engraved at their bases  20 , which may be bent from the base of the terminal block  8 . Protrusion  80  includes through holes  51  on both ends of the through groove  33 . The indentation  12  of the protrusion  11  of the stator core  2  have protrusions  50 , which fit into through holes  51  whereupon the tips are welded in order to secure the upper insulating member  5  and the lower insulating member  6  to the stator core  2 . 
   The stator assembly  1  of  FIG. 1  may be assembled in the following manner. Flat terminal pin parts  29  are inserted into the multiple through holes  31  in the terminal block  8 . The anchor posts  41  mate with the through holes  39  of the flat terminals  10 . The terminal block  8  is mated with the indentation  12  on the protruding part  11  of the stator core  2 . The lower insulating member  6  and the upper insulating member  5  fit tightly on either side of the stator core  2 , and the protrusion parts  24  mate with the through holes  26  at the tips. The tips of the mating protrusion parts  24  are welded to fasten the lower insulating member  5  and the upper insulating member  6  to the stator core  2 . 
   With reference to  FIGS. 3 and 5 , the stator core coil wires (not shown) wrap around the respective magnetic poles of the stator assembly unit  1 . The tips  35  of the stator coil wires are wrapped onto the tips of fastening pins  34  after passing between the weld parts  38  and across the slack pins  36 . The weld parts  38  of the flat terminals  10  are bent to secure the tips  35  of the stator coil wires. 
   The two electrodes  70 ,  72  of a resistive welder may respectively contact the weld part  38  and top side of each flat terminal  10  to bend the weld part  38  onto the bottom side of the flat terminal  10  and retain the tip  35  of the stator coil wire. The electrode  72  that contacts the top side of the flat terminal  10  does so by passing through the through groove  33  from the top side of the terminal block  8 . Thereafter, the stator coil wire is resistively welded to the flat terminal  10 . In this manner, the tips  35  of the stator coil wires pass through the weld parts  38  for attachment to the flat terminals  10 . The slack pins  36  thereafter are bent to secure the tips  35  of the stator coil wire to the terminal block  8 . 
   The tips of the connector terminals  30  are press fitted onto the lead lines  9 . The lead lines  9  sit in the lead line fastening grooves  32 . The connector terminals  30  mate with the ends of the flat terminal pin parts  29  passing through the terminal block  8  via the through holes  31 . The flat terminal pin parts  29  and connection terminals  30  are arc welded together. In this manner the lead lines  9  connect to the tips  35  of the stator coil wires. The bending of the slack pins  36  may be performed after completing the above-mentioned arc welding. 
   With reference to  FIG. 7  the stator assembly  1  may be assembled as follows. The flat terminals  10  are mounted on the terminal block  8  by inserting the flat terminal pin parts  29  into the through holes  31  on the upper insulating member  5 . Additionally, the anchor posts  41  of the terminal block  8  accept the through holes  39  of the flat terminals  10 . The flat terminals  10  traverse the through groove  33  as is shown in  FIG. 3   b . Protrusion  81  of the upper insulating member  5  and protrusion  80  of the lower insulating member  6  fit tightly to either side of the indentation  12  of the stator core  2 . The protrusion parts  50  and through holes  51  are mated and the tips of the protrusion parts  50  are welded, thereby securing the upper insulating member  5  and the lower insulating member  6  to the stator core  2 . 
   Although the invention described herein is with reference to particular embodiments, it should be understood that these embodiments are merely illustrative of the principals and application of the present invention. It should therefore be understood that modifications may be made to the exemplary embodiments described herein, and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the following claims.