Patent Publication Number: US-7581964-B2

Title: Unit with built-in control circuit

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is on the basis of Japanese Patent Application No. 2007-009503, the contents of which are hereby incorporated by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention relates to a unit with a built-in control circuit receiving various circuit elements to be used in connecting an electric wire or the like. 
   2. Description of the Related Art 
   Various electric components such as an air-conditioner, a windshield wiper, a power window and the like are mounted on a vehicle. A wiring harness is arranged in a vehicle for supplying electricity or a control signal to the electric components. The wiring harness includes a plurality of electric wires and a connector for receiving terminal fittings to be connected to ends of the electric wires. The electric wire is a so-called covered wire having a conductive core wire and an insulating sheath covering the core wire. 
   For example, an electronic unit having connectors disclosed in Patent Document 1 is used as a unit with a built-in control circuit in which an electronic unit is embedded for connecting the connector of the wiring harness to drive and control the electric components via the wiring harness. The electronic unit having connectors disclosed in Patent Document 1 includes: a transmission control unit  20  composed of a print circuit board on which various circuit elements are mounted; connectors at both sides of the electric unit; a unit housing receiving the transmission control unit  20 ; and a cover  13   b  for covering an opening formed on the unit housing. In each connector of the electronic unit having connectors, terminals made of conductive metal are projected from the transmission control unit  20  and connected to terminals of a mating connector. 
   When the other ends of the terminals connected to the electronic unit having connectors are connected to the other connector or various electric components, the connector disclosed in the Patent Document 1 connects the electric wires connected to the other connector and the electric component in a predetermined pattern via the electronic unit having connectors. 
   [Patent Document 1] Japanese Published Patent Application No. 2004-288425 
   In the electronic unit having connectors disclosed in the Patent Document 1, a connector for connecting the connector of the wiring harness extended from the electric component is formed on the unit housing receiving the transmission control unit  20 . Therefore, a volume of the unit housing is increased, and terminals for connecting to the connector of the wiring harness and the transmission control unit  20  are needed. Accordingly, a cost of the electronic unit is increased, and assembling time for receiving the terminals in each connector is increased. 
   Accordingly, an object of the present invention is to provide a unit with a built-in control circuit to be able to be small-sized, to reduce a cost thereof, and to make an assembling thereof easy. 
   SUMMARY OF THE INVENTION 
   In order to attain the object, according to the present invention, there is provided a unit with a built-in control circuit including: 
   a control circuit part on which circuit elements are mounted, having an electric wire connecting part; 
   a unit housing having an opening for receiving the control circuit part; and 
   a cover for holding a plurality of electric wires, covering the unit housing after attached to the opening, and connecting the electric wires to the electric wire connecting part. 
   Preferably, the control circuit part is composed of a control circuit package including: a lead frame integrally having the electric wire connecting part; the circuit elements mounted on the lead frame; and a plastic molding body in which the electric connecting part is exposed, and the circuit elements and the lead frame are molded. 
   Preferably, the electric wire connecting part includes a pressure welding blade for pressure welding the electric wire. 
   Preferably, the lead frame further includes a connector connecting part exposed from the plastic molding body, and the unit housing includes a hood for receiving the connector connecting part and for being fitted with a mating connector receiving external terminals to be connected to the connector connecting part. 
   These and other objects, features, and advantages of the present invention will become more apparent upon reading of the following detailed description along with the accompanied drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view showing a connector of a unit with a built-in control circuit and a mating connector according to an embodiment of the present invention; 
       FIG. 2  is a perspective view showing the connectors shown in  1  connected to each other; 
       FIG. 3  is an exploded perspective view showing the unit with a built-in control circuit shown in  FIG. 1 ; 
       FIG. 4  is a perspective view showing the unit with a built-in control circuit shown in  FIG. 3 ; 
       FIG. 5  is a sectional view taken on line V-V in  FIG. 3 ; and 
       FIG. 6  is a perspective view showing a control circuit package of the unit with a built-in control circuit shown in  FIG. 3 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An embodiment of a unit with a built-in control circuit  1  according to the present invention will be explained with reference to  FIGS. 1 to 6 . 
   As shown in  FIGS. 1 to 2 , the built-in control circuit  1  is connected to a mating connector  2 . The mating connector  2  includes a connector housing  3  and not-shown terminal fittings as external terminals. The connector housing  3  is made of insulating synthetic resin, and formed in a flat box shape. The connector housing  3  receives the terminal fittings. An electric wire  4  having a core wire and a sheath covering the core wire is attached to each terminal fitting. The terminal fitting is electrically connected to the electric wire attached thereto. 
   As shown in  FIGS. 3 and 4 , the built-in control circuit  1  includes an outer housing  5  and a control circuit package  6  as a control circuit part. The outer housing  5  is formed in a flat box shape, and includes a unit housing  7 , a cover  8 , and electric wire holding part  9  (shown in  FIG. 5 ). 
   The unit housing  7  is made of insulating synthetic resin, and includes a tubular hood  10 , and a control circuit package receiving chamber  11  extended from the hood  10 . The connector housing  3  of the mating connector  2  is inserted into an interior of the hood  10  to be connected to the hood  10 . The control circuit package receiving chamber  11  is formed in a U-shaped section, and an opening  12  is formed on an upper part of the control circuit package receiving chamber  11 . 
   The cover  8  is made of insulating synthetic resin, and formed in a plate shape. The cover  8  is attached to the unit housing  7 . When attached to the unit housing  7 , the cover  8  covers the opening  12 . 
   As shown in  FIG. 5 , the electric wire holding part  9  includes a plurality of electric wire receiving grooves  14  formed on the cover  8 . The electric wire receiving grooves  14  are arranged with a gap relative to each other. An electric wire  15  is inserted into an inside of the electric wire receiving groove  14  and the electric wire receiving groove  14  holds the electric wire  15 . For holding the electric wire  15 , a radius of the electric wire receiving groove  14  is a little smaller than that of the electric wire  15 . Alternatively, a locking projection is formed on the electric wire receiving groove  14  for holding the electric wire  15 . 
   The outer housing  5  positions the control circuit package  6  between the unit housing  7  and the cover  8  to receive the control circuit package  6 . 
   Incidentally, in  FIG. 4 , two electric wires  15  are held in the electric wire receiving grooves  14  at an end of the electric wire holding part  9 , U-turned in the outer housing  5 , and held at the other end of the electric wire holding part  9 . Another two electric wires  15  are held in each electric wire receiving groove  14 . However, such an arrangement is properly changed according to a circuit configuration. 
   As shown in  FIG. 6 , the control circuit package  6  includes a lead frame  16 , an IC chip  17  as a circuit element, and a plastic molding body  18 . The lead frame  16  is made of conductive metal, and integrally includes a chip holding part  19 , a plurality of crimping terminals  20  as the electric wire connecting parts, a plurality of male tabs  21  as the connector connecting parts, and a plurality of wiring parts  22 . 
   The chip holding part  19  is formed in a flat shape. The IC chip  17  is jointed on the chip holding part  19  with an epoxy resin, sliver paste, or solder. The crimping terminals  20  are arranged with a gap relative to each other. The crimping terminals  20  are disposed as many as the electric wire receiving grooves  14 . 
   Each crimping terminal  20  integrally includes a horizontal part  23  and a vertical part  24 . The horizontal part  23  is formed in a band plate shape. Front and back surfaces of the horizontal part  23  are arranged in same planes as front and back surfaces of the chip holding part  19 . The horizontal parts  23  of the crimping terminals  20  are arranged parallel to each other. The horizontal parts  23  of the crimping terminals  20  are arranged with a gap relative to the chip holding part  19 . 
   The vertical part  24  is vertically extended from an end of the horizontal part  23  away from the chip holding part  19 . In  FIG. 6 , both surfaces of the vertical part  24  are perpendicular to both surface of the horizontal part  23 . Both surfaces of the vertical part  24 , namely, both surfaces of a later-described pressure welding blade  25  is parallel to an attaching direction of the cover  8  to the unit housing  7 . 
   Further, the vertical parts  24  are extended from the horizontal parts  23  in the same direction as each other. Each vertical part  24  includes a pair of pressure welding blades  25  disposed with a gap in a width direction of the crimping terminal  20 , namely, in a direction of arranging the crimping terminals  20 . A pair of pressure welding blades  25  catches the electric wire  15  therebetween, and cuts the sheath of the electric wire  15  to contact the core wire of the electric wire  15 . 
   Each male tab  21  is formed in a bar shape and extended straight. The male tabs  21  are arranged with a gap relative to each other. The chip holding part  19  is interposed between the crimping terminals  20  and the male tabs  21 . 
   After the control circuit package  6  is received in the outer housing  5 , the male tabs  21  are connected to the terminals in the mating connector  2  fitted into the hood  10 . 
   The wiring parts  22  are formed in a curved shape for extending toward the chip holding part  19  from the crimping terminals  20  and the male tabs  21 . Some parts of the wiring parts  22  connect the chip holding part  19  to the crimping terminals  20 , and the other parts of the wiring parts  22  connect the chip holding part  19  to the male tabs  21 . 
   The IC chip  17  is disposed on the chip holding part  19 , and attached to the lead frame  16 . The IC chip  17  is connected to the wiring parts  22  with well-known bonding wires. The IC chip  17  electrically connects the crimping terminals  20  and the male tabs  21  according to a predetermined pattern via the wiring parts  22 . Thus, the IC chip  17  is mounted on the lead frame  16 . 
   The plastic molding body  18  is made of synthetic resin, and formed in a flat box shape. The plastic molding body  18  packages the chip holding part  19 , the horizontal part  23  of the crimping terminals  20 , base ends of the male tabs  21  near the chip holding part  19 , and the wiring parts  22  by receiving them in a molding die and molding. Namely, the plastic molding body  18  covers and receives the IC chip  17  and the center of the lead frame  16 . The plastic molding body  18  packages the IC chip  17  and the lead frame  16 , and the crimping terminals  20  and the male tabs  21  are exposed from the plastic molding body  18 . 
   The connector (unit with a built-in control circuit)  1  described above is assembled as described below. Firstly, the electric wire  15  is held in the electric wire holding part  9  formed on the cover  8 , and the control circuit package  6  is inserted into the unit housing  7  via the opening  12 . At this time, the male tabs  21  are positioned in the hood  10 , and the vertical parts  24 , namely, the pressure welding blades  25  are extended vertically from a bottom wall of the control circuit package receiving chamber  11 . Then, the cover  8  is gradually moved toward the opening  12 . Then, the electric wires  15  held in the electric wire receiving grooves  14  of the electric wire holding part  9  are gradually inserted into between the corresponding pressure welding blades  25  of the vertical parts  24 . Then, the cover  8  fully closes the opening  12  to be attached to the unit housing  7 , and the electric wires  15  are press-fitted into between the pressure welding blades  25 . The pressure welding blades  25  cut the sheath of the electric wire  15  and contact the core wire of the electric wire  15 . 
   Thus, the connector (unit with a built-in control circuit)  1  is assembled. This connector  1  is connected to the mating connector  2 . In the connector  1 , the IC chip  17  connects mating electric wires  4  in the mating connector  2  to the electric wires  15  press-fitted into the crimping terminals  20  according to the predetermined pattern. 
   According to this embodiment, because the crimping terminals  20  include pressure welding blades  25 , the electric wires  15  can be attached to the crimping terminals  20  only by press-fitting the electric wire  15  into between the pressure welding blades  25 . Therefore, time to connect the electric wires  15  to the crimping terminals  20  can be reduced. Therefore, the connector (unit with a built-in control circuit)  1  is easily connected to the electric wires  15 . 
   Further, because the vertical parts  24 , namely, the pressure welding blades  25  of the crimping terminals  20  are extended in a direction of moving the cover  8  toward the unit housing  7 , the electric wires  15  can be attached to the crimping terminals  20  by moving the cover  8  toward the unit housing  7 . 
   Because the electric wire holding part  9  is formed on the outer housing  5 , when the plastic molding body  18  receives the outer housing  5  after the electric wire holding part  9  holds the electric wires  15 , the electric wires  15  held in the electric wire holding part  9  can be press-fitted into between the pressure welding blade  25 . Therefore, time to connect the electric wires  15  to the crimping terminals  20  can be surely reduced, and the electric wires  15  are more easily connected to the crimping terminals  20 . 
   Because the lead frame  16  includes the male tabs  21  as the connector connecting part, a relay unit used in a conventional connector having an electronic unit is not needed. The mating connector  2  can be directly connected to the connector (unit with a built-in control circuit)  1 . 
   According to this embodiment, the lead frame  16  includes both the crimping terminals  20  as the electric wire connecting parts, and the male tabs  21  as the connector connecting parts. However, according to the present invention, the lead frame  16  only includes the electric wire connecting parts. Namely, the mating connector  2  may include the cover  8  with electric wires, and the crimping terminals  20  may be disposed at both sides of the control circuit part (the control circuit package  6 ). 
   Further, according to this embodiment, the lead frame  16  includes the crimping terminals  20  as the electric wire connecting parts. However, according to the present invention, a flat cable may be used as the electric wires, and a piercing terminal may be used for piercing core wires of the flat cable. In short, according to the present invention, various members can be used as long as they can be connected to the mating connector  2  as the connector connecting part. 
   Further, according to this embodiment, the plastic molding body  18  of the control circuit package  6  is formed in a flat shape. However, according to the present invention, the plastic molding body  18  may be formed in a hollow box body, covering the lead frame  16  and the IC chip  17 . 
   Further, according to this embodiment, the control circuit package  6  is composed of electronic elements such as the lead frame  16 , the IC chip  17  mounted on the lead frame  16 . However, according to the present invention, similar to a conventional electronic unit, the lead frame  16  may be composed of a print circuit board and electronic elements mounted on the print circuit board. In this case, when at least some parts of the terminals mounted on the print circuit board are the crimping terminals, an object of the present invention is attained. 
   Although the present invention has been fully described by way of example with reference to the accompanying drawings, it is to be understood that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention hereinafter defined, they should be construed as being included therein.