JP2010067364A - Surface-mounted connector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mounted connector that ensures positioning accuracy of a tail section of a terminal to a circuit board by preventing deformation of a housing upon reflow processing in the surface-mounted connector wherein the terminal is inserted into the housing and is inexpensive at high productivity and is not high in size. <P>SOLUTION: The surface-mounted connector 10 includes: a press-fitting section 36 having a resin housing 20 and a plurality of terminals 30 arranged in parallel by separating from the housing 20 at constant intervals and making the terminal 30 press-fit into the housing 20; and the tail section 32 which is surface-mounted on the circuit board. A core metal 40 for restraining deformation of the housing 20 along the parallel direction of the terminal 30 is buried inside the housing 20, and the core metal 40 has a dummy pin 41 which is surface-mounted on the circuit board by sticking out from the housing 20. The stress caused by press-fitting of the terminal 30 is accumulated in the housing 20, thereby the core metal 40 can restrain the deformation of the housing 20 upon reflow processing. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a surface-mount-technology (SMT) connector, and in particular, a circuit of a tail portion of a terminal press-fitted into a housing by suppressing deformation of the housing during a reflow soldering process (reflow process). The present invention relates to a surface mount connector that ensures positional accuracy with respect to a substrate.

  As a method for mounting the connector on the circuit board, the surface mounting method and the dip method are widely adopted. Of these, the surface mounting method requires a relatively small reflow facility for soldering the connector to the circuit board, enables speedy automatic mounting of the connector, and can reduce the mounting area. It is used in many electronic devices.

  In this surface mounting system, first, a solder paste is applied to a land portion prepared on a circuit board to a thickness of about 100 μm, and then a tail portion of a connector terminal is placed on the paste, thus a circuit on which a connector is mounted. The substrate is carried into a reflow furnace, heated to about 260 ° C. to melt the solder paste, taken out from the furnace and cooled to solidify the solder. By this reflow process, the tail portion of the terminal is soldered to the land portion of the circuit board.

  In the surface mounting method, it is important that the tails of each terminal are accurately aligned, that is, all the tails are in contact with the paste evenly when placed on the paste. If there is a tail portion that does not contact the paste, the tail portion is not soldered to the land portion and becomes non-conductive. Therefore, in the surface mounting method, the tail portion of each terminal is required to have high flatness (position accuracy in the vertical direction), and the flatness of each tail portion must be controlled to 100 μm or less of the thickness of the solder paste. .

  However, in a surface mount connector that is assembled by press-fitting the terminal into the housing, even if the press-fitting depth is properly controlled, the stress generated by press-fitting the terminal is accumulated in the housing. When such a connector is exposed to the above temperature in a reflow furnace, the resin structure of the housing is loosened and the accumulated stress is released, and the housing is deformed to deteriorate the flatness of the tail portion of the terminal.

  In particular, in recent years, electronic devices have become more sophisticated and smaller in size, and accordingly, connectors are also required to have multiple terminals and a narrow pitch, and the housing of the connector has tens to hundreds of terminals. Therefore, it tends to be long in the pitch direction. However, when the number of terminals of the connector is increased, it becomes more difficult to ensure the flatness of each tail portion.

  This is because if the housing of the connector becomes longer due to the increase in the number of terminals, the resin flow at the time of molding becomes complicated and stress is accumulated inside, or the cooling rate due to the difference in the wall thickness of the housing. Stress based on the difference accumulates. Furthermore, since the stress generated by press-fitting the terminal into the housing as described above also accumulates, when such a connector is exposed to the temperature in a reflow furnace and the resin structure of the housing is loosened, these are accumulated. This is because the stress that has been released is released, the housing is deformed, and the flatness of the tail portion is disturbed.

  For example, as shown in FIG. 8A, the connector 10 completed by press-fitting the terminals 30 into the elongated housing 20 has a substantially rectangular parallelepiped shape. When the connector 10 is heated in a reflow furnace, the stress is released. As shown in FIG. 8B, the housing 20 may be deformed in a mountain shape like an arch bridge in the vertical direction (Z direction) (in some cases, it may be deformed in a valley shape on the contrary). As a result, the flatness of the tail portion 32 of each terminal 30 attached to the housing 20 is disturbed. Alternatively, the housing 20 may be bent and deformed in the width direction (Y direction) by the reflow process, and the tail portion 32 may not be accurately positioned on the solder paste. Furthermore, these vertical and horizontal deformations may appear simultaneously. Hereinafter, the length direction of the housing 20 is X, the width direction is Y, and the height direction is Z.

  Conventionally, various measures have been taken against such problems as deterioration of flatness of the tail portion 32. For example, Patent Document 1 describes that “terminals are insert-molded in a housing and generation of stress due to press-fitting of the terminals is suppressed”, and Patent Document 2 describes “the upper surface of the housing and its terminal holding portion and In this case, a space is provided between the upper surface and the heat of the upper surface, which is likely to reach the highest temperature during reflow soldering, is difficult to be transmitted to the terminal holding portion, thereby preventing deformation of the housing.

JP 2008-84878 A JP 2007-87748 A

  Any of the techniques described in Documents 1 and 2 seems to have the desired effect as means for ensuring the flatness of the tail portion 32 of the terminal 30.

  However, the “terminal insert molding method” of Document 1 has to have tens to hundreds of terminals set in a mold, so that productivity is poor and it is difficult to obtain an inexpensive connector. Further, the “housing with a gap” in Document 2 not only increases the height of the connector by the amount corresponding to the gap, and the rigidity is lowered by the gap, but also makes the resin flow more complicated during molding, The difference in the cooling rate of each part also increases, and since no correspondence is made to the accumulated stress, it cannot be a fundamental solution.

  In the surface mount connector in which the number of terminals 30 is not so large and the overall length of the housing 20 (the length in the X direction) is relatively short, the deformation of the housing 20 in the Y direction has not been a problem. In the recent surface mount connector 10 in which the entire length of the housing 20 is increased, the position of the tail portion 32 of the terminal 30 is greatly displaced in the Y direction with respect to the solder paste of the circuit board due to the deformation of the housing 20 in the Y direction. Measures are strongly desired.

  The object of the present invention created in view of the above circumstances is to suppress the deformation of the housing during reflow processing in the surface mount connector formed by press-fitting the terminal into the housing, so that the position of the tail portion of the terminal with respect to the circuit board An object of the present invention is to provide a surface mount connector that can ensure accuracy, has high productivity, is inexpensive, and does not become tall.

  In order to achieve the above object, the present invention has a resin housing and a plurality of terminals arranged in parallel with the housing at intervals, a press-fit portion into which the terminals are press-fitted into the housing, and a circuit. A surface-mount connector having a tail portion that is surface-mounted on a substrate, and a cored bar for suppressing deformation of the housing is embedded in the housing along the parallel arrangement direction of the terminals, The core bar has dummy pins that protrude from the housing and are surface-mounted on the circuit board.

  The cored bar may be formed over at least the press-fitted range of the terminal along the parallel arrangement direction of the terminal.

  The cored bar may have a vertical plate part formed in a substantially rectangular shape.

  The cored bar may have a horizontal plate portion formed substantially parallel to the lower surface of the housing or the circuit board.

  According to the present invention, in a surface mount connector in which a terminal is press-fitted into a housing, the positional accuracy of the terminal tail portion with respect to the circuit board can be ensured by suppressing deformation of the housing during reflow processing, and the productivity is high. A surface mount connector that is inexpensive and does not become tall can be provided.

  Preferred embodiments of the present invention will be described with reference to the accompanying drawings.

  1 is a perspective view of a surface mount connector according to the present embodiment, FIG. 2 is a cross-sectional perspective view taken along line II-II in FIG. 1, and FIG. 3 is a cross-sectional perspective view taken along line III-III in FIG.

  A surface mount connector (socket connector) 10 according to the present embodiment includes a resin housing 20 formed into an elongated substantially rectangular parallelepiped shape by molding, and a plurality of terminals 30 arranged in parallel at intervals in the X direction on the housing 20. And have. The terminal 30 includes a press-fit portion 36 that is press-fitted into the housing 20 and a tail portion 32 that is surface-mounted on the circuit board.

  Specifically, the terminal 30 is manufactured by punching a thin metal plate and is pressed into a press-fitting groove (press-fitting hole) 23 of the housing 20. The terminal 30 is extended in the Z direction from the press-fitting part 36. The contact part 39 which contacts the terminal of a side connector (plug connector), the leg part 38 extended in the Y direction from the press-fit part 36, and the tail part 32 formed in the front-end | tip of the leg part 38 are provided. Arrow ends 35 are formed at both ends of the press-fit portion 36 to bite into both ends of the press-fit groove 23. The contact portion 39 is a so-called fork type having a pair of arms 37 extending in the Z direction from the press-fit portion 36 and a contact 34 that is formed at the tip of the arm 37 and substantially contacts the terminal of the plug connector. As the arm 37 is elastically deformed, the terminal of the mating connector is elastically clamped.

  The terminal 30 has three groups of 20 terminals 31 arranged on the left and right sides of the housing 20 in the Y direction and spaced apart in the X direction, and a total of 120 terminals are aligned and press-fitted into the housing 20. That is, the lower surface 21 of the housing 20 is provided with six press-fitting grooves 23 into which the terminals 30 are press-fitted, each having six groups (two groups in the Y direction and three groups in the X direction). Yes. Each press-fitting groove 23 is connected to an accommodating portion 26 formed in the housing 20 so as to accommodate the contact portion 39 of the terminal 30, and the accommodating portion 26 is formed in the housing 20 so that the terminal of the plug connector is fitted therein. It connects with the fitting recessed part 22 formed in the upper surface.

  A terminal 30 is press-fitted into each press-fitting groove 23 of the housing 20 by an automatic press-fitting device (not shown). When the terminals 30 are press-fitted into the press-fitting grooves 23 of the housing 20, the press-fitting depth of each terminal 30 is appropriately controlled, and the lower surface (surface with respect to the circuit board) 33 of the tail portion 32 of each terminal 30 has an allowable error ( For example, in a range of about 50 μm, it is parallel to the circuit board, that is, flat.

  Incidentally, the width of each terminal 30 is 0.2 mm, the pitch is 0.5 mm, the total length L of the housing 20 is 35 mm, the width W is 6 mm, and the height H is 3 mm.

  A cored bar 40 for suppressing deformation of the housing 20 is embedded in the housing 20 along the X direction. The cored bar 40 is formed over at least the entire range in which the terminals 30 are press-fitted along the direction in which the terminals 30 are arranged, that is, over substantially the entire length of the housing 20 in the X direction. The cored bar 40 is embedded by insert molding on both sides in the Y direction in the housing 20 so as to be spaced apart from the side surface 24 and the lower surface 21 of the housing 20.

  FIG. 4 is a perspective view of the cored bar 40. In addition, the core metal 40 shown with a broken line in FIG. 1 displays only the near side, and the back side is not shown.

  The cored bar 40 has a substantially rectangular vertical plate portion 43 having an accurate height h, thickness t, and length l, and the vertical plate portion 43 is formed on both sides of the housing 20 in the Y direction. It is embedded in parallel with the side surface 24. The cored bar 40 has dummy pins 41 that extend downward from the vertical plate portion 43 and protrude from the lower surface 21 of the housing 20. A plurality of dummy pins 41 are formed at the lower end portion of the vertical plate portion 43 at intervals in the longitudinal direction, and the lower end portions are surface-mounted on the circuit board.

  Thus, the cored bar 40 including the vertical plate portion 43 and the dummy pin 41 is manufactured by punching a thin metal plate and bending it. In the metal core 40, the vertical plate portion 43 is embedded in the housing 20 by insert molding as described above, and the dummy pins 41 protrude downward from the lower surface 21 of the housing 20.

  The dummy pin 41 extends downward from the lower end portion of the vertical plate portion 43 and penetrates the lower surface 21 of the housing 20. The dummy pin 41 extends in the Y direction from the lower end of the bridge portion 44 and is substantially surface-mounted on the circuit board. A total of eight mounting portions 45 are formed on each of the left and right vertical plate portions 43.

  The lower surface 42 (surface with respect to the circuit board) of the mounting portion 45 of each dummy pin 41 is parallel to the circuit board, that is, flat within the allowable error range. Further, the lower surface 42 of the mounting portion 45 of each dummy pin 41 and the lower surface 33 of the tail portion 32 of each terminal 30 are parallel to the circuit board within the allowable error range, that is, flat.

  Incidentally, the width of the dummy pins 41 is 1.0 mm, the pitch is 11 mm, and the vertical plate portion 43 of the cored bar 40 has an overall length l, an overall height h, and a thickness t that are the overall length L, the overall height H, and the meat of the housing 20. The relation of l <L, h <H, t <T with respect to the thickness T is established.

  The operation of this embodiment will be described.

  In the surface mount connector 10 described above, the stress generated during molding of the housing 20 and the stress generated by press-fitting the terminal 30 into the press-fitting groove 23 of the housing 20 after molding are either after molding or after terminal pressing. Is suppressed by the resin (cured state) of the housing 20.

  When such a connector 10 is reflow-processed to be surface-mounted on a circuit board, the resin structure of the housing 20 loosens and the accumulated stress is released and the housing 20 is deformed. In the surface mount connector 10, the cored bar 40 embedded in the housing 20 by insert molding over substantially the entire length resists this, and prevents the deformation of the housing 20 from becoming obvious. Therefore, the flatness of the lower surface 33 of the tail portion 32 of the terminal 30 and the lower surface 42 of the mounting portion 45 of the dummy pin 41 is not significantly changed before and after the reflow process, and the flatness is maintained within the allowable error range. be able to.

  Specifically, the cored bar 40 has a vertical plate portion 43, and this vertical plate portion 43 exhibits a large drag when the housing 20 is about to deform in the Z direction, so that the vertical deformation of the housing 20 is effective. Is blocked. Thereby, the flatness of the lower surface 33 of the tail portion 32 of the terminal 30 and the lower surface 42 of the mounting portion 45 of the dummy pin 41 can be effectively maintained within the allowable error range. Further, since the vertical plate portion 43 of the cored bar 40 exhibits a certain drag force even when the housing 20 tries to deform in the Y direction, the horizontal deformation of the housing 20 is also suppressed. Thus, the horizontal position of the lower surface 33 of the tail portion 32 of the terminal 30 and the lower surface 42 of the mounting portion 45 of the dummy pin 41 with respect to the solder paste does not change greatly before and after the reflow process, and is within the allowable error range. Maintained.

  When the vertical plate portion 43 of the core metal 40 is embedded in the housing 20 by insert molding, the dummy pin 41 extending from the vertical plate portion 43 is held in the insert molding die so that the dummy pin 41 is vertically aligned. The holding | maintenance function which positions the board part 43 correctly in the predetermined position in the said metal mold | die is exhibited. Therefore, a dedicated holding member for holding the vertical plate portion 43 at a predetermined position in the mold is not necessary. Further, since the dummy pin 41 is extended from the vertical plate portion 43 that is insert-molded in the housing 20, it is not necessary to provide the housing 20 with a press-fitting groove for the dummy pin, and therefore, the press-fitting process is unnecessary, and an inexpensive surface. The mounting connector 10 can be obtained.

  Further, the surface mount connector 10 does not need to insert-mold each terminal 30 in the housing 20 like the one described in Patent Document 1, and is inexpensive and highly productive. That is, since the surface mount connector 10 according to the present embodiment insert-molds only the cored bar 40 in the housing 20, the manufacturing cost of the housing 20 compared to the connector described in Document 1 in which all the terminals 30 are insert-molded. Since the terminal 30 is press-fitted into the housing 20 in which the metal core 40 is embedded in this manner by an automatic press-fitting device as in the prior art, the overall manufacturing cost can be kept low.

  Moreover, since the surface mount connector 10 which concerns on this embodiment has suppressed the deformation | transformation of the housing 20 at the time of a reflow process by embedding the metal core 40 by the insert molding inside the housing 20, the thing of the thing of patent document 2 is described. Thus, it is not necessary to provide a gap that functions as a heat insulating layer during the reflow process between the upper surface of the housing and the terminal holding portion, and the height H does not increase. Therefore, it is possible to cope with the thinning of electronic devices.

  The present invention is not limited to the above embodiment.

  For example, the contact part 39 of the terminal 30 may not be a fork type. Although the example in which the two terminals 30 are disposed at intervals in the width direction of the housing 20 has been shown, one terminal arrangement on only one side may be employed. The terminal 30 may not be divided into the terminal group 31. It may be a plug connector instead of a socket connector, and can be applied to any connector. Although it has been described that a dedicated holding member for the cored bar 40 is not required when the cored bar 40 is insert-molded in the housing 20, this does not prevent the holding dedicated member from being provided.

  FIG. 5 is a perspective view showing a modification of the cored bar 40. A cored bar 40a in FIG. 5 has an extension 46 extending along the width direction of the housing 20 from the tip of the vertical plate 43 of the cored bar 40 described with reference to FIG. It has become a shape. As for this metal core 40a, the vertical board part 43 is arrange | positioned along the side surface 24 (refer FIG. 1) of the housing 20, and the extension part 46 is arrange | positioned along the end surface 25 (refer FIG. 1) of the housing 20. FIG. The surface mount connector provided with the cored bar 40a has the same configuration as the surface mount connector 10 of the previous embodiment except for the extension 46, and has the same effects as the previous embodiment.

  FIG. 6 is a perspective view showing another modification of the cored bar 40. The cored bar 40b in FIG. 6 is formed by connecting both ends of the vertical plate part 43 of the pair of cored bars 40 shown in FIG. Yes. In the metal core 40b, a pair of vertical plate portions 43 are disposed along the side surface 24 (see FIG. 1) of the housing 20, and a pair of extension portions 46 are disposed along the end surface 25 (see FIG. 1) of the housing 20. The The surface mount connector provided with the cored bar 40b has the same configuration as the surface mount connector 10 of the first embodiment except for the extension 46, and has the same effects.

  FIG. 7 is a perspective view showing another modification of the cored bar 40. 7 includes a horizontal plate portion 46 that extends from the lower end portion of the vertical plate portion 43 of the core metal 40 described with reference to FIG. 4 in a direction intersecting the vertical plate portion 43 (for example, a right angle direction). It has a J shape when viewed from the longitudinal direction. The horizontal plate portion 46 is formed substantially parallel to the lower surface 21 of the housing 20 or the circuit board.

  The surface mount connector provided with the cored bar 40c has the same configuration as that of the surface mount connector 10 of the first embodiment except for the horizontal plate portion 46. In addition, the horizontal plate portion 46 is a housing. Since a great resistance against the horizontal deformation of 20 (deformation in the Y direction on the XY plane in FIG. 1) is exerted, the horizontal deformation of the housing 20 during the reflow process can be effectively suppressed.

  Further, the horizontal plate portion 46 of the metal core 40c in FIG. 7 is omitted, and the vertical plate portion 43 of the metal core 40c is curved in the horizontal direction (the vertical plate portion 43 is arcuate when viewed from the Z direction in FIG. 1). It may be insert-molded in the housing 20 as a curved shape) to prevent the housing 20 from bending in the direction opposite to the bending direction of the vertical plate portion 43 in the XY plane during the reflow process.

  Further, in FIG. 7, the vertical plate portion 43 may be omitted, and the cored bar may be configured only from the horizontal plate portion 46 and the dummy pins 41 formed thereon. 7 may be added to the cored bar 40a in FIG. 5 or the cored bar 40b in FIG.

It is a perspective view of the surface mount connector which shows one Embodiment of this invention. It is the II-II sectional view perspective view of FIG. FIG. 3 is a cross-sectional perspective view taken along line III-III in FIG. 1. It is a perspective view of a core metal. It is a perspective view which shows the modification of a metal core. It is a perspective view which shows another modification of a metal core. It is a perspective view which shows another modification of a metal core. It is explanatory drawing which shows a mode that a surface mount connector deform | transforms by a reflow process, (a) is a perspective view which shows the mode after a deformation | transformation, (b).

Explanation of symbols

10 surface mount connector 20 housing 30 terminal 32 tail part 36 press-fit part 40 cored bar 41 dummy pin 43 vertical plate part 46 horizontal plate part

Claims (4)

A resin housing and a plurality of terminals arranged side by side at a distance from the housing, the terminals including a press-fit portion that is press-fitted into the housing and a tail portion that is surface-mounted on the circuit board. A surface mount connector,
A cored bar for suppressing deformation of the housing is embedded in the housing along the parallel arrangement direction of the terminals, and the cored bar protrudes from the housing and is surface-mounted on the circuit board. A surface mount connector having a dummy pin.   The surface mount connector according to claim 1, wherein the cored bar is formed over at least the press-fitted range of the terminals along the parallel arrangement direction of the terminals.   The surface mount connector according to claim 1, wherein the core metal has a vertical plate portion formed in a substantially rectangular shape.   The surface mount connector according to any one of claims 1 to 3, wherein the core metal has a horizontal plate portion formed substantially parallel to the lower surface of the housing or the circuit board.

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