JP5089305B2 - Connector surface mounting structure and connector - Google Patents

Description

  The present invention relates to a surface mounting structure of a connector and a connector. More specifically, the present invention relates to a surface mounting structure of a connector and a connector that can securely fix a pinch pitch connector with solder.

  As a method for mounting an IC package such as a chip component or QFP on a printed circuit board, surface mounting technology is widely used. At this time, an electrical connector (hereinafter simply referred to as a connector) used for connection to an external module is also attached by a surface mounting method.

  Such connectors often have a large number of contact pins at a pitch. When the connector is placed at a predetermined position on the printed circuit board, the contact pin connection portion is located within the pad on the printed circuit board, and then the electromechanical contact between the contact pin and the pad is performed by soldering in the reflow process. A connection is made.

  Here, a technique described in Patent Document 1 is known as a technique for ensuring that the connection portion of the contact pin is positioned within the pad. According to this technique, the connecting portion of the contact pin connected to the pad includes a protruding portion extending downward from one end of the connecting portion, and the corresponding printed circuit board pad receives the protruding portion. A through hole is formed.

The procedure for placing the connector on the printed circuit board is as follows. First, adjust the contact pin connection part so that it is within the range of the pad on the printed circuit board. Further fine-tuning is performed so as to fit. If it fits in this way, this time, the force which pushes lightly downward from this position is added. If it does so, a protrusion will be settled in the back, being guided by the inner surface of a through-hole, and both will fit. In this series of operations, the protruding portion functions to correct the position of the contact pin to the correct position. In other words, contact pin position fluctuations caused by variations in processing accuracy and assembly accuracy are corrected at the protrusions, and the contact pins arranged in parallel with the connector are neatly arranged at the planned positions of the pads on the printed circuit board. It is arranged.
Japanese Utility Model Publication No. 3-52964

  According to this technology, the protrusion provided on the contact pin connecting portion is obtained by bending the tip of the contact pin made of a metal plate by 90 degrees by bending, and the processing accuracy of the protrusion is obtained by punching. It cannot be denied that it is slightly inferior to the processing and machining. For this reason, the processed shape of the contact pin including the protruding portion and the connecting portion has a large variation in detail as compared with that obtained by punching or the like.

  On the other hand, in the case of a connector in which a large number of contact pins are arranged in parallel at a pinching pitch, contact pin processing accuracy and assembly accuracy are required more than before, and the protrusion processing accuracy that corrects the positional deviation of the contact pins associated therewith However, high quality products are required.

  Accordingly, an object of the present invention is to provide a connector surface on which the contact pins can be arranged on the pads with high accuracy even in the case of a connector in which a large number of contact pins are arranged in parallel at a narrow pitch when the connector is surface-mounted on a printed circuit board. It is to provide a mounting structure and a connector.

In order to solve the above problems, the surface mounting structure of the connector according to the present invention has a contact pin extending from a connector housing fixed on a printed circuit board, and a contact portion connected to a pad formed on the printed circuit board. In a connector surface mounting structure in which the connection portion and the pad are fixed to each other by a solder in preparation for the pin, the contact pin is formed by punching, and the tip of the connection portion is in contact with the pad. The pad is provided with a ridge portion that has an inclination and protrudes downward, and the pad has a through hole that fits into the ridge portion, and the ridge portion has a diameter that is larger than the diameter of the through hole. And the length of the protruding portion is substantially equal to the length of the through hole, and the outer side of the distal end portion of the protruding portion and the inner side of the base end portion are the inner peripheral surface of the through hole due to the inclination. Close to or touching Those having features at.

  In the above-described surface mounting structure of the connector, the contact pin is formed by punching, and the connecting portion of the contact pin has a protrusion extending downward, and the printed circuit board pad has a through hole. It is to be prepared. Since the processing accuracy of the contact pin is higher than that obtained by bending, the protruding portion is accurately formed at a predetermined position of the contact pin. Therefore, even in the case of a connector in which a large number of contact pins are arranged in parallel at a narrow pitch, the contact pins can be arranged on the pads with high accuracy.

  Here, the protruding portion extends from the connection portion of the contact pin, and may extend from the connection portion to the entire length of the connection portion. The extending direction is preferably a direction perpendicular to the connecting portion, but is not limited to the direction perpendicular to the connecting portion. Further, the shape of the protrusion may take various shapes, and may be a semicircular shape, a trapezoidal shape or the like in addition to the tongue shape.

Further, through holes have been drilled in the pad, when the connection portion is positioned exactly right above the corresponding pad and confronting at the position mating the ridge and the through hole. The inner surface of the through hole is processed by plating, and this plated surface is electrically connected to the metal portion forming the pad.

  Therefore, the electrical and mechanical connection between the contact pin and the pad is ensured not only by the connection between the connection portion and the pad but also by the connection between the protrusion and the through hole, and the reliability is improved by the double connection. Yes.

  Here, in order to ensure the electrical mechanical connection between the protrusion and the through hole, the maximum width of the protrusion is preferably substantially the same as or slightly larger than the diameter of the through hole. In addition, since they are paired and have a function of correcting the position for guiding the position of the contact pin to the correct position on the pad (design position), the fitting between the two is tight. must not. On the other hand, since the connection between the two is finally brought about by the adhesion of cream solder previously applied to the pad surface, even if there is no contact point between the protrusion and the inner surface of the through hole, If in close proximity, the electromechanical connection can be achieved by the wettability of the molten solder.

  Therefore, considering the ease of mounting the connector on the printed circuit board and the wettability of the solder when mounted by reflow soldering, it is preferable that the maximum width of the protrusion is slightly smaller than the diameter of the through hole. Further, it is preferable that the length of the protrusion is approximately equal to the length of the through hole.

  Here, the reflow soldering method will be described. The cream solder previously applied to the pad surface is eluted by passing through a reflow furnace (the heat source is hot air or infrared rays), and between the contact pin connection portion and the pad, and between the protrusion and the inner surface of the through hole. It spreads in between, and the two are firmly electromechanically connected by the good wettability of the solder.

  According to the present invention, when the connector is surface-mounted on the printed circuit board, the contact pin is guided to the correct position on the pad by the protrusion provided on the contact pin connection portion, so that a large number of contacts at a narrow pitch. Even in the case of a connector in which pins are arranged in parallel, the contact pins can be arranged on the pads with high accuracy. In addition, even if the flatness (coplanarity) of the contact pin varies somewhat, as long as the protrusion can be connected to the through-hole, the electromechanical connection is ensured. The degree of regulation can be relaxed.

  Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an external perspective view of a connector and a printed circuit board according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of a state in which the protruding portion is fitted in the through hole.

  The connector 10 includes a contact pin 20 obtained by plating a metal plate, and a synthetic resin housing 30 in which the contact pin 20 is mounted. As will be described in detail later, the printed circuit board 40 includes a pad 41 that is electrically and mechanically connected to the contact pin 20, and the pad 41 includes a through hole 42.

The housing 30 has a box-like shape having an opening 31 on one side, includes a storage chamber 34 that stores the contact pin 20, and includes side surfaces 32 on four sides so as to define the storage chamber 34. and a bottom surface 33 at a position confronting. The bottom surface 33 closes the side surface 32 and holds the contact pin 20 at a predetermined position.

  The contact pin 20 is formed by punching a metal plate having a thickness of about 0.5 mm. The metal plate is preferably a good electrical conductor such as brass, phosphor bronze, or beryllium copper, and a rigid copper alloy, and the surface is preferably surface-treated with tin plating or the like to improve solder wettability. Since the contact pin 20 is formed by punching with a mold, the shape thereof is made according to the mold, and the shape of each part reflects the mold accuracy and has high accuracy. The metal species and plating methods described above are examples, and the technical scope of the present invention is not limited to the above-described metal species of metal plates, surface treatment methods, and the like.

  One end of the contact pin 20 extends outward from the housing 30 and advances straight, and then faces the printed circuit board 40 and bends immediately above it to form a connecting portion 21 at the tip. The other end is accommodated in the housing 30 and forms a contact portion 23 that waits for fitting with a corresponding connector (not shown).

  When the connector 10 is placed on the printed circuit board 40, the connecting portion 21 is positioned parallel to the surface of the printed circuit board 40, and the pad 41 formed on the printed circuit board 40 is grounded on the bottom surface (downward on the paper surface). Thus, securing by soldering is ensured. Cream solder is applied to the surface of the pad 41 in advance.

  The connection portion 21 is where the pad 41 is electrically and mechanically connected by fixing the molten solder later by passing through a reflow furnace. The connecting portion 21 has a length corresponding to the length of the pad 41 in order to secure the fixing by the solder and ensure the fixing strength. Moreover, the connection part 21 is provided with the protrusion part 22 in the lower side.

  The protruding portion 22 is a tongue-like fitting portion that extends downward from the central portion of the lower side of the connecting portion 21. The protrusion 22 is formed by punching integrally with the main body of the contact pin 20 and is formed with high accuracy reflecting the mold accuracy in the same manner as the main body. That is, the protrusion 22 is accurately located at a predetermined position of the connecting portion 21 and extends from the protrusion 22 with a predetermined angle (90 degrees in the present embodiment).

  Therefore, by aligning the tip of the ridge 22 with the edge of the through hole 42 provided in the pad 41 and pushing it in from the place where it is joined, the connecting portion 21 is subjected to some position correction, Naturally, the pad 41 is grounded at a predetermined position (designed position).

  The procedure for placing the connector 10 on the printed circuit board 40 will be described in detail with reference to FIGS. 1 and 2 while touching the operational advantages of forming the protrusion 22 integrally with the contact pin 20 by punching. explain. In order to clarify the instructed direction, the direction is defined on the paper surface of FIG. The direction above the arrow on the page is the top, the direction below the arrow is down, the direction right is the front, and the direction left is the back.

  Since the contact pin 20 is formed by punching a metal plate with a die, the contact pin 20 is more resistant to a force applied in the front-rear direction or the up-down direction than a rigidity force applied to a force applied in a direction penetrating the paper surface. The rigidity of the material is exerted strongly on the general characteristics of the material. That is, the ridge 22 applies a strong rigidity to an external force applied in the front-rear direction. This characteristic is effectively exhibited in this series of operations in which the end of the protrusion 22 is aligned with the edge of the through-hole 42 and the connection portion 21 is grounded to a predetermined position of the pad 41. is there.

That is, when mounting the connector 10 to the printed circuit board 40, the contact pins 20 arranged in the longitudinal direction of the connector 10, and parallel to the printed circuit board 40 is confronting to the corresponding pad 41 located Hold on. Then, the connector 10 is lowered in its posture so that all the contact pins 20 are grounded to the corresponding pads 41. At this time, first, the tips of all the protrusions 22 are slightly inserted into the through holes. 42, the connector 10 is slightly moved in the front-rear direction and the left-right direction so as to fit together, and the position where both fit together is determined. When the positions where the tips of all the protrusions 22 are within the edge of the through hole 42 are determined, the connector 10 is lowered and placed on the printed circuit board 40. At the same time, a holder (not shown) provided in the housing 30 is fitted into an engagement hole (not shown) formed in the printed circuit board 40.

  In this way, when the connector 10 is placed on the printed circuit board 40, the connection portion 21 is at a predetermined position of the corresponding pad 41, and all the contact pins 20 arranged in parallel at a narrow pitch connect to the corresponding pad 41. Is in a state. Here, the fine adjustment of the connector 10 when determining the position where both of the above fit together is performed so that the tips of all the protrusions 22 fit into the through-holes 42. When the protrusion 22 is located at a position slightly deviating from the center of the through hole 42, the protrusion 22 slides on the inner surface of the through hole 42, and the displacement is large. The resistance force due to this sliding acts so as to push the ridge 22 upward, and prevents the ridge 22 from entering.

  At this time, the contact pin 20 of the present embodiment exerts a strong rigidity against the vertical change as described above, and therefore can resist this push-up force to a considerable range. On the other hand, in the case of the prior art in which the contact pin is formed by bending and the protrusion is formed by bending the tip of the contact pin, as described above, the rigidity force against the vertical change is weak, so this push-up The limit of succumbing without being able to resist is low.

  Therefore, the contact pin according to the embodiment of the present invention can be used even when the contact pin according to the prior art that forms the protrusion by bending is not able to resist the above-described push-up force and the contact pin is lifted from the pad. In order to resist such push-up force, the protrusion 22 can be fitted into the through-hole 42 as planned.

  In other words, when the contact pin 20 is displaced due to an unavoidable action in the process, the contact pin 20 according to the embodiment of the present invention has a larger allowable range of displacement than that according to the prior art. . From a different point of view, this means that the contact pin 20 according to the embodiment of the present invention is a technique corresponding to surface mounting with a narrower pitch. Further, when viewed from the manufacturing site of the connector 10, it means that the range of the limit value of dimensional management such as coplanarity can be relaxed.

  Next, the effect | action of the protrusion part 22 is demonstrated in detail, referring FIG.3 and FIG.4. FIG. 3 is a front view of the connector according to the embodiment of the present invention mounted on a printed circuit board. (A) is a state in which the printed circuit board is not warped. (B) is a state in which the printed circuit board is warped. FIG. 4 is an enlarged cross-sectional view of the fitting portion between the connection portion and the pad according to the embodiment of the present invention. (A) is sectional drawing which followed the AA line of (A) of FIG. (B) is sectional drawing which followed the BB line of (B) of FIG.

  In order to fix the connector 10 to the printed circuit board 40, as described above, the printed circuit board 40 on which the connector 10 is placed at a predetermined position is passed through a reflow furnace, and the cream-like solder previously applied to the pads 41 is applied. The contact pin 20 is fixed to the pad 41 by melting.

  3A (FIG. 4A) is a case where the printed circuit board 40 is not warped, and the connection portions 21 of the contact pins 20 are grounded to all the pads 41, and the through holes 42 are deeply inside. The protrusion 22 is fitted to the end. The connection part 21 and the pad 41 are fixed by the molten solder by the solder applied to the surface of the pad 41 in advance. At the same time, the protrusion 22 fitted in the through hole 42 is also fixed to the inner surface of the through hole 42 by molten solder.

  Thus, in addition to the connection portion 21 and the pad 41 being fixed, the protrusion 22 and the through hole 42 are fixed, and a double strong between the contact pin 20 and the pad 41 is realized. An electromechanical connection is ensured.

  3B (FIG. 4B) shows a case where the printed circuit board 40 is warped, and the bottom surface of the connecting portion 21 is grounded to the pad 41 between the pad 41 and the contact pin 20. There are no places. Even if such a gap is generated, the inner surface of the through hole 42 and the protrusion 22 are connected by molten solder at the tip of the protrusion 22 fitted in the through hole 42. . At this time, since the plating layer constituting the inner surface of the through hole 42 is electrically connected to the metal part forming the pad 41, the electrical machine between the contact pin 20 and the pad 41 is connected by this connection. Connection is secured.

  As described above, even when the printed circuit board 40 is warped and there is a slight gap between the connection portion 21 and the pad 41, there is a range in which the tip of the protruding portion 22 is fitted in the through hole 42. As long as it can be fixed by fusion solder between them, the contact pins 20 and the pads 41 are ensured to be electrically and mechanically connected as planned.

Therefore, according to the embodiment of the present invention, the following effects can be obtained.
(1a) Since the protrusion portion is provided in the contact pin connecting portion, the contact pin can be easily aligned with the pad.
(2a) Since the contact pin and the protrusion provided on the contact pin are formed by punching, the entire contact pin including the protrusion is accurately formed. Therefore, when the connector is surface-mounted on the printed board, the contact pins can be arranged on the pads with high accuracy even in the case of a connector in which a large number of contact pins are arranged in parallel at a narrow pitch.
(3a) Even if the printed circuit board is warped and there is a gap between the contact pin and the pad, the contact pin and the pad are electrically connected by molten solder as long as the tip of the protrusion is fitted in the through hole. Mechanical connection can be ensured.
(4a) Since the operations and effects described in (3a) above also work when the contact pins vary in the vertical direction, the tolerance of the flatness (coplanarity) of the contact pins can be increased.

In addition, this invention is not limited to embodiment described above, When it changes into another embodiment (another example) as follows, it is contained in the technical scope of this invention. Various modifications can be made without departing from the scope of the invention.
(1b) In the above-described embodiment, the contact pin goes straight from the housing, then extends vertically downward, and then bends at a right angle again to contact the printed circuit board surface to connect to the connection portion. The shape is not limited to this. As shown in FIG. 5, the contact pin may be substantially S-shaped. Even when such a shape is adopted, the effects described in (1a) to (4a) above can be obtained.
(2b) In the above embodiment, the shape of the ridge portion is a tongue piece and extends vertically from the connection portion, but is not limited to the tongue piece shape, and extends vertically from the connection portion. It is not limited to what you do. As shown in FIG. 6, the shape may be trapezoidal or semicircular, and the protruding portion may extend slightly inclined from the connecting portion. Even in such a case, the effects described in (1a) to (4a) above can be obtained.

1 is an external perspective view of a connector and a printed circuit board according to an embodiment of the present invention. It is sectional drawing of the state which the protrusion part of embodiment of this invention fitted in the through-hole. It is a front view of the state which mounted the connector of embodiment of this invention in the printed circuit board. (A) is a case where there is no curvature in a printed circuit board. (B) shows a case where the printed circuit board is warped. It is sectional drawing of the fitting part of the protrusion part and pad of embodiment of this invention. (A) is sectional drawing which followed the AA line of (A) of FIG. (B) is sectional drawing which followed the BB line of (B) of FIG. It is sectional drawing of the principal part of other embodiment of this invention. It is sectional drawing of the principal part of other embodiment of this invention.

Explanation of symbols

10 Connector (Electrical connector)
20 120 Contact pin 21 Connection portion 22 122 222 322 Projection portion 23 Contact portion 30 Housing 31 Opening portion 32 Side surface 33 Bottom surface 34 Accommodating chamber 40 Printed circuit board 41 Pad 42 Through-hole

Claims (2)

A contact pin extends from a housing of a connector fixed on the printed circuit board, and a connection portion connected to a pad formed on the printed circuit board is provided on the contact pin, and the connection portion and the pad are fixed by soldering. In the connector surface mounting structure,
The contact pin is formed by punching, and a surface of the connection portion that contacts the pad is provided with a protrusion that protrudes downward with a tip end inclined outward, and the pad has the protrusion. A through-hole that fits into the ridge is formed, the ridge has a narrower width than the diameter of the through-hole, and the length of the ridge is substantially equal to the length of the through-hole, A surface mounting structure for a connector, characterized in that an outer side of a distal end portion of the ridge portion and an inner side of a base end portion are close to or in contact with an inner peripheral surface of the through hole due to the inclination.   A connector comprising the contact pin according to claim 1.

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