A molded circuit component unit for connecting lead wires and a method of manufacturing same

Abstract: A molded circuit component for connecting to lead wires includes body and a protective cover. The body includes a partition wall area having a plurality of housing grooves, partition walls, body notches, positioning projections and fastening pin reception apertures. The protective cover includes a plurality of cover notches, recesses and fastening pins to correspond respectively with the body notches, positioning projections and fastening pin reception apertures. Metal lines having connection terminals on their ends are embedded in the housing grooves. Lead wires are positioned in the grooves so that the conductors of the lead wires are placed on, and attached to, the connection terminals. The protective cover is then attached to the body.

Description: BACKGROUND OF THE INVENTION Field of Invention The present invention relates to a molded circuit component for connecting lead wires of round cross section to electric wires of flat cross section in domestic, industrial or motor vehicle internal wiring. Description of Related Art Conventional methods and apparatus are known for connecting flat angular conductors of a flat electric cable to lead wires. In one of the methods, the conductors and the lead wires are connected to each other through a printed circuit board by soldering. In another of the methods, the electric cable and the lead wires are coupled to separate connectors and the connectors are then mounted on a printed circuit board. A separate electrical connector for connecting a plurality of round lead wires to respective terminal pins for insertion into a suitable socket is disclosed in US-A-4 225 205. The connector is made from a molded plastic component comprising a central bar member which receives the parallel array of terminal pins and is formed unitary with pivotable top and bottom support members which close together to form a protective body which encloses the lead wires. Respective wire positioning grooves are formed in the top and bottom support members so that the individual wires are maintained in a secure and strain-free position. Staggered ribs which grip the wires are also provided to further ensure strain relief. FIG. 1 (Prior Art) is a perspective view for describing a conventional method of connection. FIG. 1 shows a molded body 1, lead wires 2, a flat electric cable 3, flat angular conductors 4, crimped terminals 5, a comb-shaped spacer 6, and welded joints 7. To connect the flat electric cable 3 made of the flat angular conductors 4 to the lead wires 2 fitted with the crimped terminals 5 at the lead wire ends, the end portions of the flat angular conductors 4 are overlaid on those of the crimped terminals 5 and then spot welded thereto to comprise the welded joints 7 for the electrical connection. The lead wires 2 are then put in the spacer 6. The assembly of these members is thereafter put in the box-shaped molded body 1 and sealed with a molding resin. To connect round cross section lead wires to flat electrical cable or round cross section lead wires to a printed circuit board, it is necessary that the connectors are coupled to exposed terminals on the printed circuit board. The mutual contact surfaces of the connectors and the terminals are then soldered to each other in order to maintain reliable electrical stability of the connector contacts and the terminals and the mechanical strength of the contacts subject to vibration, especially in a motor vehicle, for extended periods of time. If some anxiety remains after the coupling and the soldering, the mutual contact surfaces can be spot welded to each other for higher reliability. In that case, the electrodes of a spot welder are set at the mutually overlaid portions of the terminals and the flat conductors of the cable and these portions are then vertically pressed together by the electrodes. However, the terminals and the flat conductors can shift rightward or leftward relative to each other. In other words, it is difficult to accurately position the terminals and the conductors with respect to each other. Furthermore, there is a possibility that the mutually coupled portions of the terminals and the conductors can be uncoupled from each other by an external force. A plug connector for flat conductor strip lines is known from US-A-3 641 482. In this connector, the conductor strips are positioned in a spaced-parallel arrangement whereby the terminal portion of the strip is adapted to be received in a flat connector construction having contacts for conductive engagement with the conductors of the strip. SUMMARY OF THE INVENTION According to the present invention, the above-mentioned problems are solved by a molded circuit component for connecting lead wires of round cross-section to electric wires of flat cross-section, the terminal end thereof for connecting with the round wires comprising the features set out in claim 1. A molded circuit component including a body and a protective cover is used. The body is made of a molding resin and has a partition wall area in which a plurality of housing grooves, partition walls, notches for fastening the lead wires, connection terminals, positioning projections and a plurality of fastening pin reception holes are provided at prescribed intervals so that the notches are located at front ends of the housing grooves and the projections are located on outer surfaces of the body and the partition walls. A plurality of metal lines are embedded in the body so that the lines comprise the connection terminals at the ends of the lines. The protective cover has recesses, fastening pins and notches corresponding to the projections, reception holes and notches of the body. The lead wires are housed in the housing grooves so that the conductors of the wires are located on the connection terminals. The conductors and the terminals are then pressed together by the electrodes of a spot welder and spot welded to each other. The protective cover is then fitted to the body and the molded circuit component is coated with molding resin. With the foregoing in mind, other objects, features and advantages of the present invention will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form part of this specification, wherein like reference numerals designate corresponding parts in the various figures. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (Prior Art) is a perspective view for describing a conventional method of connection; FIG. 2 is a perspective view of a molded circuit component which is an embodiment of the present invention; FIG. 3 is a perspective view of a protective cover; FIG. 4 is a side view of a lead wire having a round cross section and provided with a crimped terminal; FIG. 5 is a perspective view of the component with a lead wire positioned in place; and FIG. 6 is a perspective view of a molded unit. DETAILED DESCRIPTION OF THE PREFERRED EXEMPLARY EMBODIMENTS FIG. 2 is a perspective view of a molded circuit component 10 which is an embodiment of the present invention. Shown in FIG. 2 are the component 10, metal lines 11, the body 12 of the component, connection terminals 13, a partition wall area 14, housing grooves 15, partition walls 16, notches 17, projections 18, and reception holes 19. The component is made of a thermoplastic resin. The connection terminals 13 are comprised of ends of the metal lines 11, and are disposed in parallel with each other and embedded in the body 12 made of molding resin. The partition wall area 14 is provided on the front portion of the body 12. The housing grooves 15, partition walls 16 and notches 17 are provided at prescribed intervals in the partition wall area 14. The notches 17 are for preventing lead wires from being pulled out of the component 10 and are located at the front portions of the housing grooves 16. The connection terminals 13 are exposed at the rear of the housing grooves 16. The partition wall area 14 has projections 18 and reception holes 19 for securing a protective cover 20 for protecting the mutually connected portions of the terminals 13 and the lead wires, if necessary. FIG. 3 shows the protective cover 20 for protecting the partition wall area 14. The protective cover 20 has recesses 18′, fastening pins 19′ and notches 17′ corresponding to the projections 18, reception holes 19 and notches 17 so that the protective cover 20 can be fitted over the partition wall area 14. FIG. 4 shows a lead wire 40 which has a round cross section conductor 41 and a crimped terminal 5 so as to be used together with the molded circuit component 10. After an end of the lead wire 40 is removed of a coating insulator 42, the terminal 5 is put in contact with the conductor 41 and crimped so that the terminal 5 is attached to the lead wire 40. FIG. 5 shows the lead wire 40 positioned in groove 15 and notch 17 of the molded circuit component 10 so that the terminal 5 is put in contact with the connection terminal 13 of the metal line 11. The terminals 5 and 13 are then welded to each other by the electrodes of a spot welder so that the lead wire 40 is connected to the metal line 11. The protective cover 20 is then fitted over the partition wall area 14 so that the projections 18 coincide with the recesses 18' and the reception holes 19 coincide with the fastening pins 19'. The interior of the component 10 is thus protected by the cover 20. The lead wire 40 is vertically pinched at the notches 17 and 17' so that the wire is prevented from being pulled of the housing groove 15. FIG. 6 shows a molded unit 61 manufactured by molding a resin such as PBT and polyacetate on the molded circuit component 10 fitted with the protective cover 20 after the lead wires 40 are connected to the metal lines 11. The body 12 and the protective cover 20 protect the coating insulators 42 of the lead wires 40 from the heat of the high temperature resin in the molding. If the connection terminals 13 are provided on a printed circuit board which includes an electrical insulator, the bottoms of the connection terminals are exposed so that the insulator will not come between the electrodes of the spot welder and prevent electrical current from flowing from one of the spot welder electrodes to the other. In a method provided in accordance with the present invention, the lead wires are placed in the housing grooves so that the wires are accurately positioned for the spot welding. Further, the coating insulators of the lead wires are prevented from melting due to the heat of the molding resin to prevent short-circuiting or insulation failure between the mutually adjacent conductors of the wires. Since the molded circuit component and the coating insulators of the lead wires at the connected ends thereof are integrated together in the form of a box by the molding, the reliability and resistance to the pulling-out of the connected portions thereof, the bending of the component, humidity, chemicals and other environmental hazards is increased. It is preferable that the molded assembly of the component and the wires withstand pulling that could overstrain the component, wires and the connections therebetween.

Claims: A molded circuit component for connecting lead wires (40) of round cross-section to electric wires (11) of flat cross-section, the terminal end thereof for connecting with said round lead wires comprising: a body (12) comprising: a partition wall area (14) comprising a plurality of housing grooves (15) and a plurality of partition walls (16); a plurality of body notches (17) for fastening the lead wires; and a plurality of fastening pin reception apertures (19); and a protective cover (20) comprising: a plurality of fastening pins (19') corresponding to the plurality of fastening pin reception apertures; and a plurality of cover notches (17') corresponding to the plurality of body notches; characterized in that the notches of the body (12) are positioned at front portions of the housing grooves, the body (12) further comprising a plurality of connection terminals (13) comprising ends of a plurality of metal lines (11), the connection terminals exposed at rear portions of the housing grooves, the metal lines embedded in the body; and a plurality of positioning projections (18) located on the partition walls, and the cover (20) further comprising a plurality of recesses (18') corresponding to the plurality of positioning projections, whereby the lead wires (40) can be positioned in the grooves (15) such that conductors of the lead wires will be attached to connection terminals (13) when the protective cover (20) is attached to the body (12). A molded circuit component of claim 1 wherein the lead wire conductors (40) are attached to the connection terminals by welding. A molded circuit component of claim 2 wherein the welding is spot welding. A molded circuit component of claim 1 wherein the molded circuit component (10) is coated with a molding resin (61) after the protective cover is attached to the body. A molded circuit component of claim 1 wherein the body (12) is made of a molding resin. A molded circuit component of claim 1 wherein the protective cover (20) is made of a molding resin.

Inventors: HATASE HIROSHI, KANNO TOORU, KAWASAKI SYUSAKU, KOJIMA KEIICHI, MATSUDA TATSUO, SAEN HARUO, SAITO KATSUYA, SUGAWARA KIYOTO, URUSHIBATA KENICHI, YOSHIZAWA NORIO, YUMOTO TETSUO, HATASE, HIROSHI, KANNO, TOORU, KAWASAKI, SYUSAKU, KOJIMA, KEIICHI, MATSUDA, TATSUO, SAEN, HARUO, SAITO, KATSUYA, SUGAWARA, KIYOTO, URUSHIBATA, KENICHI, YOSHIZAWA, NORIO, YUMOTO, TETSUO, KANNO, TOORU, C/O SANKYO KASEI, CO., LTD., KOJIMA, KEIICHI, C/O YOKOHAMA WORKS OF, MATSUDA, TATSUO, C/O KANTOH WORKS OF, SAEN, HARUO, C/O KANTOH WORKS OF, SUGAWARA, KIYOTO, C/O KANTOH WORKS OF, URUSHIBATA, KENICHI, C/O KANTOH WORKS OF, YOSHIZAWA, NORIO, C/O SANKYO KASEI, CO., LTD., YUMOTO, TETSUO, C/O SANKYO KASEI, CO., LTD.
Applicants: MATSUSHITA ELECTRIC IND CO LTD, SANKYO KASEI KK, SUMITOMO ELECTRIC INDUSTRIES, MATSUSHITA ELECTRIC INDUSTRIAL CO., LTD., SANKYO KASEI CO., LTD., SUMITOMO ELECTRIC INDUSTRIES, LTD.
Application year: 1990
Main classification: H01R13
IPC codes: H01R12, H01R13, H02G15, H01R43, H01R4