Electrical connector

An electrical connector includes an insulating housing provided with a plurality of first contacts. Each of the first contacts has a tine that extends toward an outside of the insulating housing that is bent at a right angle with respect thereto. A tine plate is mounted on a side of the insulating housing. A circuit board is arranged adjacent to the undersurface of the tine plate and spaced there from. The tines extend through first through-holes in the tine plate and first through-holes in the circuit board. The tine plate has at least one first recess provided on the undersurface of the tine plate that encompasses at least one of the first though-holes on the tine plate. Molten solder is provided in the first through-holes in the circuit board and forms a fillet on the tines that extends toward the undersurface of the tine plate.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the filing date under 35 U.S.C. §120 of International Patent Application No. PCT/JP2006/316985 filed Aug. 29, 2006 that claims the benefit of Japanese Patent Application No. 2005-313202 filed Oct. 27, 2005.

FIELD OF THE INVENTION

The present invention relates to an electrical connector comprising a tine plate into which fillet of solder on the tines of the contacts do not encroach when the tines are connected by soldering to a circuit board via the tine plate.

BACKGROUND

FIGS. 12 and 13(see Japanese Patent Application Kokai No. H7-302653) show an example of a conventional electrical connector101. The electrical connector101comprises a tine plate130having a construction which is such that solder142sufficiently rises into through-holes141a,141b,141c, and141din a circuit board140when the tines122a,12b,122c, and122dof contacts120a,120b,120c, and120dare soldered to the circuit board140via the tine plate130. As shown inFIG. 12, the electrical connector101comprises an insulating housing110that extends in a direction of length (a direction perpendicular to a plane of the page inFIG. 12), the contacts120a,120b,120c, and120dthat are secured to the housing110in four rows in a vertical direction, and the tine plate130. The contacts120a,120b,120c, and120din the four rows respectively comprise contact members121a,121b,121c, and121dthat are fastened to the housing110that make contact with mating contacts (not shown in the figures), and tines122a,122b,122c, and122d. The tines122a,122b,122c, and122dextend from the contact members121a,121b,121c, and121dtoward a rear of the housing110(a direction opposite of a mating surface, i.e., rightward inFIG. 12) and then are bent downward at a right angle. The tines122aof the contacts120ain a first row from a bottom of the housing110are designed such that the portions of the tines122athat are bent at a right angle are positioned on an innermost side (leftmost side inFIG. 12and on the side close to the housing110) of the housing110and are respectively inserted into the through-holes141ain a first row of the circuit board140that are located on the innermost side (leftmost side inFIG. 12and on the side close to the housing110) of the housing110and are respectively connected by soldering to a conductor layer on inner surfaces of the through-holes141a. Moreover, the tines122bof the contacts120bin a second row from the bottom are designed such that the portions of the tines122bthat are bent at a right angle are located in a second position from the inside and that the tines122bare respectively inserted into the through-holes141bin a second row of the circuit board140that are located in the second position from the inside and are respectively connected by soldering to a conductor layer on the inner surfaces of the through-holes141b. In addition, the tines122cof the contacts120cin a third row from the bottom are designed such that the portions of the tines122cthat are bent at a right angle are located in a third position from the inside and that the tines122care respectively inserted into the through-holes141cin a third row of the circuit board140that are located in the third position from the inside and are respectively connected by soldering to a conductor layer on the inner surfaces of the through-holes141c. Likewise, the tines122dof the contacts120din a fourth and uppermost row are designed such that the portions of the tines122dthat are bent at a right angle are positioned on an outermost side and that the tines122dare respectively inserted into the through-holes141din a fourth row of the circuit board140and are located on the outermost side and are respectively connected by soldering to a conductor layer on the inner surfaces of the through-holes141d.

The tine plate130is constructed from a substantially rectangular plate that extends in the direction of length of the housing110and has through-holes131a,131b,131c, and131din four rows formed in positions corresponding to the through-holes141a,141b,141c, and141din the circuit board140. Moreover, tapered members132a,132b,132c, and132dfor easily guiding the respective tines122a,122b,122c, and122dinto the through-holes131a,131b,131c, and131dare provided in the through-holes131a,131b,131c, and131don a side of the insertion of the tines. In addition, once the tines122a,122b,122c, and122dare inserted into the through-holes131a,131b,131c, and131din the tine plate130, the tines122a,122b,122c, and122dcan be respectively aligned with the through-holes141a,141b,141c, and141din the circuit board140.

Projections132that extend in the direction of length are respectively provided on an undersurface of the tine plate130on an inside of the through-holes131ain the first row from the inside (on a side close to the housing110), between the through-holes131bin the second row from the inside and the through-holes131cin the third row from the inside, and on the outside of the through-holes131din the fourth row on the outermost side. As a result, when the electrical connector101is mounted on the circuit board140by respectively inserting the tines122a,122b,122c, and122dinto the through-holes131a,131b,131c, and131din the tine plate130, and respectively inserting the tines122a,122b,122c, and122dprotruding from the undersurface of the tine plate130into the through-holes141a,141b,141c, and141din the circuit board, the projections132contact an upper surface of the circuit board140. This creates a step difference between the upper surface of the circuit board140and the undersurface of the tine plate130, and the through-holes131a,131b,131c, and131dare positioned in a portion of the lower step. Consequently, a gap is created between the tine plate130and the circuit board140where the through-holes131a,131b,131c, and131dare formed in the tine plate130.

Then, when the tines122a,122b,122c, and122dare connected by soldering to the through-holes141a,141b,141c, and141din the circuit board140in a subsequent soldering process, if a reverse side of the circuit board140that is mounted on the electrical connector101is exposed to a molten solder jet, a capillary action occurs in each of the through-holes141a,141b,141c, and141dbecause of the existence of appropriate space inside the through-holes141a,141b,141c, and141dbetween the inner walls and the tines122a,122b,122c, and122d. Accordingly, as is shown inFIG. 13, the solder142that is in a molten state moves up inside each of the through-holes141a,141b,141c, and141din the circuit board140to the upper surface of the circuit board140due to the capillary action. The solder142further draws up each of the tines122a,122b,122c, and122dfrom the upper surface of the circuit board140due to the surface tension, and a tip end of the solder142in each of the through-holes141a,141b,141c, and141dforms a fillet143that reaches near the tine plate130. However, the following problem has been encountered in the electrical connector101. Specifically, the tine plate130is designed such that a gap is created between the undersurface of the tine plate130and the upper surface of the circuit board140by making the plate thickness smaller (thinner) in all portions having the through-holes131a,131b,131c, and131d; therefore, the surface area of the portions of the tine plate130where the gap is created from the circuit board140occupies most of the total surface area, creating a problem in that the mechanical strength is insufficient. In particular, when the electrical connector101comprising the tine plate130is mounted on a circuit board used for an automobile engine control unit, the electrical connector101is subjected to a large temperature difference and vibration during use, so that the mechanical strength of the tine plate130becomes a problem.

SUMMARY

It is an object of the present invention to provide an electrical connector comprising a tine plate in which the mechanical strength of the tine plate is not lowered, and a fillet of solder drawn up tines arranged in the tine plate can be prevented from encroaching on the tine plate.

This and other objects are achieved by an electrical connector comprising an insulating housing provided with a plurality of first contacts. Each of the first contacts has a tine that extends toward an outside of the insulating housing that is bent at a right angle with respect thereto. A tine plate is mounted on a side of the insulating housing. The tine plate has a plurality of first through-holes that extend from an upper surface to an undersurface of the tine plate. The tines extend through the first through-holes. The tine plate has at least one first recess provided on the undersurface of the tine plate that encompasses at least one of the first though-holes.

DETAILED DESCRIPTION OF THE EMBODIMENT(S)

Next, an embodiment of the present invention will be described with reference to the figures. As shown inFIG. 1, the electrical connector1is designed such that a plurality of mating connectors50(only one of the mating connectors50is shown inFIG. 1) mate with the electrical connector1. As shown inFIGS. 1 through 7, the electrical connector1comprises a housing10, a tine plate30, first contacts20a,20b,20c,20d,20e, and20fin a plurality of rows and columns (6 rows and 25 columns in the present embodiment), second contacts21a,21b,21c, and21din a plurality of rows and columns (4 rows and 3 columns in the present embodiment), and third contacts22a,22b,22c, and22din a plurality of rows and columns (4 rows and 6 columns in the present embodiment) which are secured to the housing10. With regard to the first contacts, the first contacts20ain a bottommost row inFIG. 3are first-row first contacts, the first contacts20bin a second row from the bottom are second-row first contacts, the first contacts20cin a third row from the bottom are third-row first contacts, the first contacts20din a fourth row from the bottom are fourth-row first contacts, the first contacts20ein a fifth row from the bottom are fifth-row first contacts, and the first contacts20fin a topmost row are sixth-row first contacts. Furthermore, with regard to the second contacts, the second contacts21ain a bottommost row inFIG. 3are first-row second contacts, the second contacts21bin a second row from the bottom are second-row second contacts, the second contacts21cin a third row from the bottom are third-row second contacts, and the second contacts21din a topmost row are fourth-row second contacts. Moreover, with regard to the third contacts, the third contacts22ain a bottommost row inFIG. 3are first-row third contacts, the third contacts22bin a second row from the bottom are second-row third contacts, the third contacts22cin a third row from the bottom are third-row third contacts, and the third contacts22din a topmost row are fourth-row third contacts.

The housing10is formed by molding an insulating resin and comprises a substantially rectangular housing base11that extends in the direction of length (left-right direction inFIGS. 2 and 3), and a substantially rectangular mating member12that protrudes forward (toward the bottom inFIG. 2) from the housing base11and that extends in the direction of length. A plurality of mating connector mating recesses13(six of the recesses13in the present embodiment) with which the mating connectors50mate are formed in the mating member12of the housing10. Moreover, a pair of locking members14for locking the tine plate30is provided on either end of the housing base11in the direction of length.

As shown inFIGS. 1 through 3, the first contacts20athrough20fare attached substantially to a central portion of the housing10in a direction of length along the direction of length of the housing10, the second contacts21athrough21dare provided in a right end portion of the housing10in the direction of length along the direction of length of the housing10, and the third contacts22athrough22dare provided in a left end portion of the housing10in the direction of length along the direction of length of the housing10.

Here, the first contacts20athrough20fin the first through sixth rows are fastened to the housing base11and comprise contact members20a1,20b1,20c1,20d1,20e1, and20f1(seeFIG. 3) that extend into four mating connector mating recesses13located substantially in a central portion of the housing10in the direction of length. The first contacts20athrough20fin the first through sixth rows also respectively comprise tines20a2,20b2,20c2,20d2,20e2, and20f2(seeFIG. 6) that respectively extend from the contact members20a1through20f1toward a rear of the housing base11(toward an outside of the housing10and upward inFIG. 2). The tines20a2through20f2are formed by being bent downward at a right angle after extending toward the rear of the housing base11. Each of the first contacts20athrough20fin the first through sixth rows is constructed from a pin member that is formed by stamping and forming a metal plate.

The second contacts21athrough21din the first through fourth rows are fastened to the housing base11and comprise contact members21a1,21b1,21c1, and21d1(seeFIG. 3) that extend into the mating connector mating recess13located at a right end portion of the housing in the direction of length. The second contacts21athrough21din the first through fourth rows also respectively comprise tines21a2,21b2,21c2, and21d2(seeFIG. 6) that respectively extend from the contact members21a1through21d1toward the rear of the housing base11(toward the outside of the housing10and upward inFIG. 2). The tines21a2through21d2are formed by being bent downward at a right angle after extending toward the rear of the housing base11. As shown inFIG. 6, the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21din the second column from the right side of the housing10in the direction of length respectively extend to positions that are shifted rearward with respect to the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21din the first and third columns, which are adjacent to the second column on both sides thereof. As a result, the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21din the respective rows are arranged in a staggered fashion along the direction of length of the housing10. Furthermore, each of the second contacts21athrough21din the first through fourth rows is constructed from a pin member that is formed by stamping and forming a metal plate.

The third contacts22athrough22din the first through fourth rows are fastened to the housing base11and comprise contact members22a1,22b1,22c1, and22d1(seeFIG. 3) that extend into the mating connector mating recesses13located at a left end portion of the housing in the direction of length. The third contacts22athrough22din the first through fourth rows also respectively comprise tines22a2,22b2,22c2, and22d2(seeFIG. 6) that respectively extend from the contact members22a1through22d1toward the rear of the housing base11(toward the outside of the housing10and upward inFIG. 2). The respective tines22a2through22d2are formed by being bent downward at a right angle after extending toward the rear of the housing base11. As shown inFIG. 6, the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22din the first, third, and fifth columns from the left side of the housing10in the direction of length respectively extend to positions that are shifted rearward with respect to the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22din the second, fourth, and sixth columns, which are adjacent to the first, third, and fifth columns on both sides thereof. As a result, the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22din the respective rows are arranged in a staggered fashion along the direction of length of the housing10. In addition, each of the third contacts22athrough22din the first through fourth rows is constructed from a pin member that is formed by stamping and forming a metal plate.

As shown inFIGS. 2,6, and7, the tine plate30is constructed from a substantially rectangular plate-form body that extends in the direction of length (left-right direction inFIG. 2), and is formed by molding an insulating resin. As is shown inFIGS. 2 and 6, first through-holes30a,30b,30c,30d,30e, and30fin a plurality of rows and columns (6 rows and 25 columns in the present embodiment) into which the right-angled bent portions of the tines20a2through20f2of the first contacts20athrough20fin the plurality of rows and columns are respectively inserted are formed in the tine plate30. The first through-holes30athrough30fare formed substantially in a central portion of the tine plate30in the direction of length along the direction of length of the tine plate30corresponding to the right-angled bent portions of the tines20a2through20f2of the first contacts20athrough20f. The first through-holes30athrough30fin the respective rows are arranged in a staggered fashion along the direction of length of the housing10. Furthermore, the first through-holes30athrough30fare formed in positions corresponding to first through-holes40athrough40f(seeFIG. 10) in a circuit board40. With regard to the first through-holes30athrough30f, the first through-holes30ain a row closest to the housing10inFIG. 2are first-row first through-holes, the first through-holes30bin a second closest row are second-row first through-holes, the first through-holes30cin a third closest row are third-row first through-holes, the first through-holes30din a fourth closest row are fourth-row first through-holes, the first through-holes30ein a fifth closest row are fifth-row first through-holes, and the first through-holes30fin a row farthest to the housing10are sixth-row first through-holes. Furthermore, tapered members30a′ and30b′ (only the tapered members30a′ and30b′ that are respectively provided in the first through-holes30aand30bin the first and second rows are shown inFIG. 11) for easily guiding the tines20a2through20f2into the through-holes30athrough30fare provided in the respective first through-holes30athrough30fon a side of the insertion of the tines20a2through20f2.

Second through-holes31a,31b,31c, and31din a plurality of rows and columns (4 rows and 3 columns in the present embodiment) into which the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21din the plurality of rows and columns are respectively inserted are formed in the tine plate30. The second through-holes31athrough31dare formed in a right end portion of the tine plate30in the direction of length along the direction of length of the tine plate30corresponding to the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21d. The second through-holes31athrough31din the respective rows are arranged in a staggered fashion along the direction of length of the housing10. Moreover, the second through-holes31athrough31dare formed in positions corresponding to second through-holes (not shown in the figures) in the circuit board40. With regard to the second through-holes31athrough31d, the second through-holes31ain a row closest to the housing10inFIG. 2are first-row second through-holes, the second through-holes31bin a second closest row are second-row second through-holes, the second through-holes31cin a third closest row are third-row second through-holes, and the second through-holes31din a row farthest to the housing10are fourth-row second through-holes. Furthermore, tapered members (not shown in the figures) for easily guiding the tines21a2through21d2into the second through-holes31athrough31dare provided in the second through-holes31athrough31don a side of the insertion of the tines21a2through21d2.

Third through-holes32a,32b,32c, and32din a plurality of rows and columns (4 rows and 6 columns in the present embodiment) into which the perpendicular portions of the respective tines22a2through22d2of the third contacts22athrough22din the plurality of rows and columns are respectively inserted are formed in the tine plate30. The third through-holes32athrough32dare formed in a left portion of the tine plate30in the direction of length along the direction of length of the tine plate30corresponding to the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22d. The third through-holes32athrough32din the respective rows are arranged in a staggered fashion along the direction of length of the housing10. Furthermore, the third through-holes32athrough32dare formed in positions corresponding to third through-holes (not shown in the figures) in the circuit board40. With regard to the third through-holes32athrough32, the third through-holes32ain a row closest to the housing10inFIG. 2are first-row third through-holes, the third through-holes32bin a second closest row are second-row third through-holes, the third through-holes32cin a third closest row are third-row third through-holes, and the third through-holes32din a row farthest to the housing10are fourth-row third through-holes. In addition, tapered members (not shown in the figures) for easily guiding the tines22a2through22d2into the third through-holes32athrough32dare provided in the third through-holes32athrough32don the side of the insertion of the tines22a2through22d2.

The right-angled bent portions of the tines20a2through20f2of the first contacts20athrough20fare respectively inserted into the first through-holes30athrough30fin the tine plate30. The first through-holes30athrough30fhave the function of aligning the inserted right-angled bent portions with the first through-holes formed in the circuit board40. Similarly, the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21dare respectively inserted into the second through-holes31athrough31din the tine plate30. The second through-holes31athrough31dhave the function of aligning the inserted right-angled bent portions with the second through-holes formed in the circuit board40. Moreover, the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22dare respectively inserted into the third through-holes32athrough32din the tine plate30. The third through-holes32athrough32dhave the function of aligning the inserted right-angled bent portions with the third through-holes formed in the circuit board40. Furthermore, the tine plate30is designed to be locked with the locking members14provided on the housing10and to restrict the downward movement after the right-angled bent portions of the tines20a2through20f2of the first contacts20athrough20fare respectively inserted into the first through-holes30athrough30f, the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21dare respectively inserted into the second through-holes31athrough31d, and the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22dare respectively inserted into the third through-holes32athrough32d.

As shown inFIGS. 2 and 6, first recesses33are formed in the undersurface of the tine plate30within regions encompassing all of the first through-holes30aand30bthat are present within regions encompassing the first through-holes30aand30bin the first and second rows that are adjacent to the housing10. The cross-sectional shape of each of the first recesses33is rectangular as shown inFIG. 11. The depth of the first recesses33is approximately 1 mm in the present embodiment. Furthermore, the thickness of the tine plate30is approximately 2 mm.

Similarly, as shown inFIGS. 2 and 6, a second recess34is formed in the undersurface of the tine plate30in a region encompassing all of the second through-holes31athrough31dthat are present within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length. The cross-sectional shape of the second recess34is similar to the shape of the first recesses33, and the depth of the second recess34is also approximately 1 mm.

Likewise, as shown inFIGS. 2 and 6, a third recess35is formed in the undersurface of the tine plate30in a region encompassing all of the third through-holes32athrough32dthat are present within a region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length. The cross-sectional shape of the third recess35is similar to the shape of the first recesses33, and the depth of the third recess35is also approximately 1 mm.

Next, a method for mounting the electrical connector1on the circuit board40will be described with reference toFIGS. 8 through 11. First, prior to the mounting of the electrical connector1on the circuit board40, the right-angled bent portions of the tines20a2through20f2of the first contacts20athrough20fare respectively inserted into the first through-holes30athrough30fin the tine plate30, the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21dare respectively inserted into the second through-holes31athrough31d, and the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22dare respectively inserted into the third through-holes32athrough32d. Afterward, the tine plate30is locked with the locking members14provided on the housing10.

Then, as shown inFIGS. 8,10, and11, the right-angled bent portions of the tines20a2through20f2of the first contacts20athrough20fare respectively inserted into the first through-holes40a,40b,40c,40d,40e, and40fthat are formed in the circuit board40at the same time, the right-angled bent portions of the tines21a2through21d2of the second contacts21athrough21dare respectively inserted into the second through-holes (not shown in the figures) formed in the circuit board40at the same time, and the right-angled bent portions of the tines22a2through22d2of the third contacts22athrough22dare respectively inserted into the third through-holes (not shown in the figures) formed in the circuit board40at the same time. As a result, the electrical connector1is carried on one end portion of the circuit board40as shown inFIG. 10. In this state, the undersurface of the tine plate30and the upper surface of the circuit board40are separated by a specified distance as shown inFIGS. 10 and 11. The specified distance is preferably greater than the so-called draw-up height (height of fillet42), which is the level to which molten solder41crawls up and reaches the tine surfaces from the upper surface of the circuit board40due to surface tension.

In the insertion of the right-angled bent portions of the tines20a2through20f2,21a2through21d2, and22a2through22d2, the first through-holes30athrough30fin the tine plate30respectively align the right-angled bent portions of the tines20a2through20f2with the first through-holes40athrough40f, the second through-holes31athrough31drespectively align the right-angled bent portions of the tines21a2through21d2with the second through-holes (not shown in the figures), and the third through-holes32athrough32drespectively align the right-angled bent portions of the tines22a2through22d2with the third through-holes (not shown in the figures). Therefore, the insertion of the respective right-angled bent portions is performed smoothly.

Then, as shown inFIG. 11(only the solder connection in the first through-holes40athrough40fis shown inFIG. 11), the soldering of the right-angled bent portions of the tines20a2through20f2, the right-angled bent portions of the tines21a2through21d2, and the right-angled bent portions of the tines22a2through22d2is respectively performed in the first through-holes40athrough40f, the second through-holes (not shown in the figures), and the third through-holes (not shown in the figures). As a result, the first contacts20athrough20f, the second contacts21athrough21d, and the third contacts22athrough22dof the electrical connector1are electrically connected to the circuit board40.

When soldering is performed as described above, a capillary action occurs in each of the first through-holes40athrough40f, the second through-holes (not shown in the figures), and the third through-holes (not shown in the figures). As a result, as is shown inFIG. 11, the molten solder41moves up to the upper surface of the circuit board40inside the first through-holes40athrough40f, the second through-holes (not shown in the figures), and the third through-holes (not shown in the figures) in the circuit board40due to the capillary action. Furthermore, the molten solder41draws up the right-angled bent portions of the respective tines20a2through20f2,21a2through21d2, and22a2through22d2from the upper surface of the circuit board40due to the surface tension, and the tip end of the molten solder41in each of the first through-holes40athrough40f, the second through-holes (not shown in the figures), and the third through-holes (not shown in the figures) forms the fillet42that reaches the vicinity of the halfway position between the tine plate30and the circuit board40. Thus, because the tine plate30and the circuit board40are separated by a specified distance, i.e., a distance greater than the so-called draw-up height (height of the fillet42), which is the level to which the molten solder41crawls up and reaches the tine surfaces from the upper surface of the circuit board40due to the surface tension, the fillet42of the molten solder41do not encroach on the tine plate30.

Here, as is shown inFIGS. 2,6, and11, the first recesses33are formed in the undersurface of the tine plate30in regions encompassing all of the first through-holes30aand30bthat are present within regions encompassing the first through-holes30aand30bin the first and second rows that are adjacent to the housing10. Therefore, the distance between the circuit board40and the undersurface of the tine plate30can be made greater than in the past in the regions in which the first recesses33are formed and which encompass the first through-holes30aand30b, so that the fillet42of the molten solder41drawing up the tines20a2and20b2when the tines20a2and20b2are connected by soldering to the circuit board40can be reliably prevented from encroaching on the tine plate30in the portions where the first recesses33are formed.

Moreover, as is shown inFIGS. 2 and 6, the second recess34is formed in the undersurface of the tine plate30in a region encompassing all of the second through-holes31athrough31dthat are present within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length. Therefore, the distance between the circuit board40and the undersurface of the tine plate30can be made greater than in the past in the region in which the second recess34is formed and which encompasses the second through-holes31athrough31d, so that the fillet42of the molten solder41that draws up the tines21a2through21d2when the tines21a2through21d2are connected by soldering to the circuit board40can be reliably prevented from encroaching on the tine plate30in the portion where the second recess34is formed.

In addition, as is shown inFIGS. 2 and 6, the third recess35is formed in the undersurface of the tine plate30in a region encompassing all of the third through-holes32athrough32dthat are present within a region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length. Therefore, the distance between the circuit board40and the undersurface of the tine plate30can be made greater than in the past in the region in which the third recess35is formed and which encompasses the third through-holes32athrough32d, so that the fillet42of the molten solder41that draws up the tines22a2through22d2when the tines22a2through22d2are connected by soldering to the circuit board40can be reliably prevented from encroaching on the tine plate30in the portion where the third recess35is formed.

Furthermore, the first recesses33, the second recess34, and the third recess35formed in the undersurface of the tine plate30are formed in the undersurface of the tine plate30in regions encompassing some of the through-holes among the first through-holes30athrough30f, second through-holes31athrough31d, and third through-holes32athrough32din the plurality of rows and columns. Accordingly, there is no drop in the mechanical strength of the tine plate30.

Here, in cases where the thermal expansion coefficients of the tine plate30and circuit board40are different, a difference is generated between the amounts of expansion and contraction of the tine plate30and the amounts of expansion and contraction of the circuit board40by the variations in the temperature, and stress is repeatedly generated in the parts soldered to the circuit board40via the tines20a2through20f2,21a2through21d2, and22a2through22d2, so that cracking may occur in these soldered parts. Meanwhile, the tines20a2and20b2that are shorter in length among the tines20a2through20f2of the first contacts20athrough20fin the plurality of rows and columns are respectively inserted into the first through-holes30aand30bthat are present within the regions encompassing the first through-holes30aand30bin the two rows adjacent to the housing10. Therefore, these portions where the first through-holes30aand30bare present are portions where the tine plate30is more predisposed to restraint than the other portions. That is, because the shorter tines20a2and20b2are less likely to undergo deformation than the longer tine parts, the tine plate30is more predisposed to restraint in the portions having the first through-holes30aand30binto which the shorter tines20a2and20b2are inserted than in the other portions.

Accordingly, in cases where the circuit board40and tine plate30thermally expand due to the temperature variations, the expansion and contraction of the portions of the tine plate30which have the first through-holes30aand30bthat are present within the regions encompassing the first through-holes30aand30bin the two rows adjacent to the housing10are more easily restrained, and the difference from the amounts of expansion and contraction of the circuit board40is increased, so that an excessive force is applied to the tines20a2and20b2from the tine plate30, resulting in a problem in that the stress on the soldered parts is increased. Thus, because the first recesses33are formed in regions encompassing all of the first through-holes30aand30bthat are present within regions encompassing the first through-holes30aand30bin the two rows adjacent to the housing10, the restraint of the expansion and contraction of these portions having the first through-holes30aand30bcan be alleviated in cases where the tine plate30thermally expands due to the temperature variations; as a result, stress on the soldered parts can be reduced.

Furthermore, the third recess35is formed in a region encompassing all of the third through-holes32athrough32dthat are present within a region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length. Moreover, the second recess34is formed in a region encompassing all of the second through-holes31athrough31dthat are present within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length. In cases where the thermal expansion coefficients of the tine plate30and circuit board40are different as described above, a difference is generated between the amounts of expansion and contraction of the tine plate30and the amounts of expansion and contraction of the circuit board40by the variations in the temperature, and stress is repeatedly generated in the parts soldered to the circuit board40via the tines20a2through20f2,21a2through21d2, and22a2through22d2, so that cracking may occur in these soldered parts. Here, in cases where thermal expansion takes place due to the temperature variations, the amounts of expansion and contraction in the direction of length of the tine plate30are accumulated within the region that is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length and within the region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length, so that these amounts of expansion and contraction are large.

Accordingly, in cases where the circuit board40and tine plate30thermally expand due to the temperature variations, the amounts of expansion and contraction become too large in the portion having the third through-holes32athrough32dthat are present within the region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length and in the portion having the second through-holes31athrough31dthat are present within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length, so that the difference from the amounts of expansion and contraction of the circuit board40become large. As a result, an excessive force is applied to the tines21a2through21d2and22a2through22d2, creating the problem of increasing the stress on the soldered parts. Accordingly, by forming the third recess35in the region encompassing all of the third through-holes32athrough32dthat are present within a region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length, and by forming the second recess34in the region encompassing all of the second through-holes31athrough31dthat are present within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length, it is possible to reduce the amounts of expansion and contraction of the portions having these third through-holes32athrough32dand second through-holes31athrough31din cases where the tine plate30thermally expands due to the temperature variations; as a result, the stress on the soldered parts can be reduced.

An embodiment of the present invention has been described above. However, the present invention is not limited to this embodiment, and various alterations and modifications can be made. For example, the arrangement of the through-holes formed in the tine plate30is not limited to a plurality of rows and columns, and may also be in a single row and a plurality of columns or in a plurality of rows and a single column. Furthermore, the recesses formed in the undersurface of the tine plate30are not limited to the first recesses33formed in regions encompassing all of the first through-holes30aand30bthat are present within regions encompassing the first through-holes30aand30bin the first and second rows adjacent to the housing10, the second recess34formed in a region encompassing all of the second through-holes31athrough31dthat are present within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length, and the third recess35formed in a region encompassing all of the third through-holes32athrough32dthat are present within a region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length. It is sufficient if the recesses are formed in the undersurface of the tine plate30in regions encompassing some of the through-holes among the first through-holes30athrough30f, the second through-holes31athrough31d, and the third through-holes32athrough32din a plurality of rows and columns. In this case, the distance between the circuit board40and the undersurface of the tine plate30can be made greater than in the past in regions encompassing the through-holes where the recesses are formed, so that the fillet42of the molten solder41drawing up the tines when the tines20a2through20f2,21a2through21d2, and22a2through22d2are connected by soldering to the circuit board40can be reliably prevented from encroaching on the tine plate30in the portions where the recesses are formed. Moreover, because the recesses are formed in the undersurface of the tine plate30in regions encompassing some through-holes among the first through-holes30athrough30f, the second through-holes31athrough31d, and the third through-holes32athrough32din a plurality of rows and columns, there is no drop in the mechanical strength of the tine plate30.

In addition, the recesses formed in the undersurface of the tine plate30are not limited to the first recesses33, the second recess34, and the third recess35; it would also be possible to form a recess in a region encompassing the first through-holes, the second through-holes, or the third through-holes that are present in a portion near the housing10. In this case, it is possible to alleviate the restraint on the expansion and contraction of the portion of the tine plate30that has the first through-holes, the second through-holes, or the third through-holes that are present near the housing10in cases where the tine plate30thermally expands due to the temperature variations; as a result, the stress on the soldered parts can be reduced.

Furthermore, the formation of the first recesses33is not limited to regions encompassing all of the first through-holes30aand30bthat are present within regions encompassing the first through-holes30aand30bin the first and second rows adjacent to the housing10; it would also be possible to form the first recess33in a region encompassing either one or a plurality of the first through-holes30aand30b. In this case, it is possible to alleviate the restraint on the expansion and contraction of the portion having either one or a plurality of the first through-holes30aand30bpresent within regions encompassing the first through-holes30aand30bin the two rows adjacent to the housing10in cases where the tine plate30thermally expands due to the temperature variations; as a result, the stress on the soldered parts can be reduced.

Moreover, the recesses formed in the undersurface of the tine plate30are not limited to the first recesses33, second recess34, and third recess35, and may also be formed in regions encompassing the second through-holes31athrough31dand the third through-holes32athrough32dthat are present in either end portion of the tine plate30in the direction of length. In this case, it is possible to reduce the amounts of expansion and contraction of the portions having the second through-holes31athrough31dand the third through-holes32athrough32dthat are present in either end portion of the tine plate30in the direction of length in cases where the tine plate30thermally expands due to the temperature variations; as a result, the stress on the soldered parts can be reduced.

In addition, the formation of the third recess35is not limited to a region encompassing all of the third through-holes32athrough32dthat are present within a region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length; the third recess35may also be formed in a region encompassing either one or a plurality of the third through-holes32athrough32d. In this case, it is possible reduce the amounts of expansion and contraction of the portion having one or a plurality of the third through-holes32athrough32dpresent within a region which is 20% of the length of the tine plate30in the direction of length from the left end of the tine plate30in the direction of length in cases where the tine plate30thermally expands due to the temperature variations; as a result, the stress on the soldered parts can be reduced.

Furthermore, the formation of the second recess34is not limited to a region encompassing all of the second through-holes31athrough31dthat are present within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end of the tine plate30in the direction of length; the second recess34may also be formed in a region encompassing either one or a plurality of the second through-holes31athrough31d. In this case, it is possible to reduce the amounts of expansion and contraction of the portion having one or a plurality of the second through-holes31athrough31dpresent within a region encompassing the second through-holes31athrough31din the three columns adjacent to the right end the tine plate30in the direction of length in cases where the tine plate30thermally expands due to the temperature variations; as a result, the stress on the soldered parts can be reduced.