JP2009194118A - Surface-mount electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface-mount electronic component that enhances the positioning accuracy on a mounting board without complicating a structure to allow for mounting by the use of an automatic mounting machine. <P>SOLUTION: A connector 1 has a positioning pin 11 that can be inserted into a positioning hole 21 on a mounting board 2 and is provided with a position restriction member 111 consisting of a thermal expansion member, shape-memory member and the like that come into contact with the inner face of the positioning hole 21 to restrict a position of the positioning pin 11 in the event of thermal deformation. Thermal deformation and subsequent contact with the inner face of the positioning hole 21 of the position restriction member 111 restricts a position of the positioning pin 11 inside the positioning hole 21, and ensures accurate positioning of the connector 1 on the mounting board 2. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electronic component that performs SMT mounting (surface mount technology) on a mounting substrate, and more particularly to a surface mounting type electronic component that can increase the positioning accuracy of the electronic component relative to the mounting substrate.

In various electronic devices, SMT mounting is used as a technology for mounting electronic components on a mounting board. Especially in recent small electronic devices such as mobile phones and portable terminals, electronic components to be mounted in the device assembly process are automatically mounted. There is a technique of mounting on a mounting board using a solder, and performing soldering by mounting and reflowing solder after mounting. In order to use such an automatic mounting machine, it is necessary to accurately position and mount the electronic component at a predetermined position on the mounting board. For this reason, the electronic component has a structure for positioning with respect to the mounting board. . For example, in the SMT mounting of Patent Document 1, a positioning structure as shown in a conceptual diagram in FIG. 1 is provided. In the figure, a wiring land 22 having a conductive film formed in a required pattern is formed on the surface of the mounting substrate 2, and a plurality of (in this case, two) positioning holes 21 for positioning electronic components are opened. ing. On the other hand, the connector 1 as an electronic component is provided with a plurality of elastic contacts 12 on an insulating body 10 and is in conductive contact with other electronic components not shown in the drawing. The base end portion of the elastic contact 12 is extended to a position along the bottom surface of the insulating body and is configured as a terminal 13 protruding from the insulating body 10 and soldered to the wiring land 22 when mounted on the mounting board 2. . In addition, two positioning pins 11 protrude from the bottom surface of the insulating body 10, and the connector 1 is positioned with respect to the mounting board 2 by being fitted into the positioning holes 22 of the mounting board 2.
JP 2007-200599 A

  In the SMT technique of Patent Document 1, the tolerance between the positioning pin 11 and the positioning hole 21 becomes a problem. By design, if the positioning pin 11 cannot be fitted into the positioning hole 12, mounting becomes impossible, and the positioning hole 11 includes the tolerance of the diameter dimension of the positioning pin 11 due to the positional accuracy when mounting the automatic mounting device. The inner diameter dimension of 21 is designed to be slightly smaller. For this reason, a gap called a backlash occurs between the outer peripheral surface of the positioning pin 11 and the inner peripheral surface of the positioning hole 21, and when the connector 1 shown in FIG. Due to the surface tension, the connector 1 moves on the surface of the mounting board 2 by the gap dimension generated between the positioning pin 11 and the positioning hole 21, and the mounting position of the connector 1 with respect to the mounting board 2 becomes unstable. . Therefore, there arises a problem that the elastic contact 12 of the mounted connector 1 cannot be brought into electrical contact with a counterpart component or device in a suitable state.

  To solve such problems, it is possible to perform highly accurate positioning by inserting the positioning pins into the positioning holes in close contact with each other. However, such high-accuracy processing is extremely difficult, and the processing cost increases. This will increase the cost of parts. It is also possible to absorb the gap between the two by forming the positioning pin with an elastic member and inserting the positioning pin into the positioning hole while elastically deforming the positioning pin, but in order to realize a structure having elasticity in the radial direction. The structure of the positioning pin is complicated, which causes a high cost. Moreover, since the force which resists an elastic force is requested | required when mounting, smooth mounting using an automatic mounting machine becomes difficult.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a surface-mount type electronic component that can improve the positioning accuracy with respect to a mounting substrate without complicating the structure and increasing the cost, and enables mounting of an automatic mounting machine.

  The present invention relates to a surface-mount electronic component that is mounted on a mounting board having positioning holes and has positioning pins that can be inserted into the positioning holes. The positioning pins contact the inner surface of the positioning holes when thermally deformed. A position restraining member for restraining the position of the positioning pin is provided. This position restricting member is constituted by a thermal expansion member that thermally expands when heated, or a thermal deformation member that thermally deforms when heated. For example, the position restricting member is configured to thermally expand at the solder reflow temperature or to be thermally deformed and contact the inner surface of the positioning hole.

  According to the present invention, the position restraining member is thermally deformed and abuts against the inner surface of the positioning hole, so that the position restraining member is interposed in the gap between the positioning hole and the positioning pin. The movement of the positioning pins is restricted. As a result, the position of the positioning pin within the positioning hole is uniquely determined without unnecessarily complicating the structure of the positioning pin and without increasing the cost, and the electronic component having the positioning pin Can be positioned with high accuracy with respect to the mounting substrate, and an electronic component suitable for SMT mounting using an automatic mounting machine can be obtained.

  As a preferred embodiment of the present invention, the position restricting member is provided on a part of the circumference of the positioning pin, and is brought into contact with a part of the inner peripheral surface of the positioning hole when deformed. The positioning pin is restrained by the position restraining member while being pressed against the inner peripheral surface opposite to the positioning hole, and is positioned at this position. Alternatively, the position restraining member is provided over the entire circumference of the positioning pin, and is brought into contact with the entire inner peripheral surface of the positioning hole when deformed. The positioning pin is positioned concentrically with the positioning hole.

  Next, a first embodiment in which the present invention is applied to the connector shown in FIG. 1 will be described. FIGS. 2A and 2B are a side view and a bottom view in which a part of the positioning pin 11 of the connector 1 is inserted into the positioning hole 21 of the mounting board 2 when the connector 1 is mounted on the mounting board 2. FIG. It is. As shown in FIG. 1, the connector 1 has two elastic contacts 12 arranged side by side on the front side of the insulating body 10 (right side of FIG. 2, the same applies hereinafter), and terminals extended from these elastic contacts 12 on the rear side. 13 is arranged in a state of protruding along the bottom surface of the insulating body 10. Further, two positioning pins 11 are formed on the bottom surface of the insulating body 10 of the connector 1 so as to protrude downward and integrally with the insulating body 10. The mounting board 2 is also provided with wiring lands 22 on the surface in the same manner as shown in FIG. 1, and positioning holes 21 are provided so as to penetrate the mounting board 2 in the thickness direction. Although not shown in the drawing, a solder layer is formed on the wiring land 22 by plating or the like, and the terminals 13 of the connector 1 can be surface-mounted by soldering by solder reflow.

  FIG. 3 is an external view showing details of the two positioning pins 11 described above. The positioning pin 11 is formed in a columnar shape having a truncated cone shape at the lower end directed downward. The outer diameter of the cylindrical portion of the positioning pin 11 is formed to be smaller than the inner diameter of the positioning hole 21. Here, the positioning pin 11 has a circumferential portion on the front side of the cylindrical peripheral surface with respect to the mounting substrate. Processed to serve as a reference for connector position. A notch groove 112 that is recessed in the radial direction is formed in a circumferential portion on the rear surface side of the positioning pin 11, and a thermal expansion member 111 as a position restraining member of the present invention is integrated into the notch groove 112 by adhesion. Is attached. The thermal expansion member 111 is formed in a semi-cylindrical shape corresponding to the inside of the notch groove 112, and the outer arc surface thereof is embedded in the notch groove 112 along the circumferential surface of the positioning pin 11. It is arranged. The thermal expansion member 111 may be made of a material having heat resistance against the heating temperature at the time of solder reflow and having a much larger thermal expansion coefficient than the resin of the insulating body 10 constituting the positioning pin 11. For example, rubber, high thermal expansion resin, high thermal expansion metal, etc. can be applied.

  In FIG. 2, a connector 1 is mounted on a mounting board 2 placed in a flat state by an automatic mounting machine that does not appear in the drawing. At this time, by inserting the positioning pins 11 of the connector 1 into the positioning holes 21 of the mounting board 2, the terminals 12 of the connector 1 are respectively arranged on the wiring lands 22 of the mounting board 2. At this time, since the gap between the outer diameter of the positioning pin 11 and the inner diameter of the positioning hole 21 is generated, smooth mounting is possible even with an automatic mounting machine. Then, when heat treatment is performed, the solder provided on the wiring land 22 reflows, and the terminal 13 is soldered to the wiring land 22. At this time, as shown in FIGS. 4A and 4B, a longitudinal sectional view and a partially broken bottom view, the thermal expansion member 111 in the notch groove 112 is thermally expanded by heating. Due to this thermal expansion, the thermal expansion member 111 expands between the circumferential portion on the rear surface side of the positioning pin 11 and the inner peripheral portion on the rear surface side of the positioning hole 21 and is filled between them. The positioning pin 11 is moved as shown by the arrow in FIG. 4B by the drag generated between the member 111 and the rear surface side inner peripheral portion of the positioning hole 21, and the circumferential portion on the front side is the front side of the positioning hole 21. It is contact | abutted to the inner peripheral part. Therefore, if the positioning hole 21 is set and opened so that the inner peripheral portion of the front surface side of the positioning hole 21 becomes a position reference with respect to the connector 1, the positions of the two positioning pins 11 and the positioning holes 21 are set. The reference comes into contact, and at least the position of the front surface side of the connector 1 with respect to the mounting substrate 2 can be positioned in a self-aligning manner with high accuracy. When the heating is finished in this state, the solder is solidified, the terminals 13 are integrated with the wiring lands 22, and the mounting of the connector 1 on the mounting board 2 is finished.

  FIG. 5 is a detailed view of the positioning pin 11 of the second embodiment. In the second embodiment, the positioning pin 11 is formed such that the diameter of the column portion is smaller than the diameter of the lower end portion to form the circumferential groove 112A over the entire circumference, while the thermal expansion member 111A is cylindrical as a position restraining member. It is formed in a shape and is fitted into the circumferential groove 112A of the positioning pin 11. Here, a slit 111a is provided in a part of the circumference of the thermal expansion member 111A, and the slit 111a is used for fitting. According to the structure of the positioning pin 11, when the connector 1 is mounted on the mounting board 2 as in the first embodiment, when the positioning pin 11 is inserted into the positioning hole 21 and heat treatment for solder reflow is performed, As shown in FIGS. 6 (a) and 6 (b), a longitudinal sectional view and a partially broken bottom view, the thermal expansion member 111A is enlarged in diameter over the entire circumferential portion, and is positioned on the entire circumferential surface. It will be in the state contact | abutted to the whole inner peripheral surface of the hole 21. FIG. As a result, the center of the positioning pin 11 is aligned with the center of the positioning hole 21. Therefore, here, if the center position of the positioning pin 11 is formed to be the position reference of the connector 1 and the positioning hole 21 is also formed to be the position reference of the center position, the connector 1 is mounted on the mounting substrate 2. Can be aligned in a self-aligning manner.

  7A and 7B are a longitudinal sectional view and a partially broken bottom view of the connector 1 equipped with the positioning pins of the third embodiment in a mounted state. In the third embodiment, the circumferential groove 112B and the diameter hole 112C connected thereto are provided in the cylindrical portion of the positioning pin 11, the shape memory alloy wire 111B is inserted into the diameter hole 112C as a position restricting member, and both ends thereof are circumferentially connected. It is formed in an arc shape along the groove 112B so that the shape viewed from the bottom surface is substantially similar to an S shape. According to this, when the connector 1 is mounted on the mounting board 2 as in the first embodiment, when the positioning pin 11 is inserted into the positioning hole 21 and heat treatment for solder reflow is performed, the shape memory alloy wire 111B The both ends are restored in shape toward the outer diameter direction and come into contact with the inner peripheral surface of the positioning hole 21. As a result, the center of the positioning pin 11 is aligned with the center of the positioning hole 21. Therefore, if the center position of the positioning pin 11 is formed so as to be the position reference, and the positioning hole 21 is formed so that the center position is the position reference as in the second embodiment, the connector 1 is mounted on the mounting board 2. On the other hand, it can be aligned in a self-aligning manner. Although illustration is omitted, if the shape memory alloy wire 111B is formed only toward the rear surface side of the positioning pin 11, the positioning pin 11 is moved in the front direction in the positioning hole 21 as in the first embodiment. In this case, it is possible to realize alignment based on the positional reference between the front peripheral surface portion of the positioning pin 11 and the front peripheral surface inner surface portion of the positioning hole 21.

  In each of the above embodiments, an example of a connector having two positioning pins is shown, which is configured for positioning on the front side where the elastic contact 12 of the connector 1 exists, but is orthogonal to this. When three or more positioning pins are provided to perform positioning in the same direction, the position restraining member of the present invention is provided for all of these positioning pins or for the selected positioning pins. do it.

  The position restraining member of the present invention is not limited to the materials and shapes of the first to third embodiments, and is thermally expanded or deformed by heating during the solder reflow process. The present invention can be applied as long as the positioning pin can be restrained in position by contacting the entire surface or a part thereof.

  In the above embodiment, the present invention is applied to a connector mounted on a mounting board. However, SMT mounting is performed on the mounting board while performing solder reflow or the like, and the positioning hole provided in the mounting board at that time is mounted. The present invention can be similarly applied to any electronic component provided with a positioning pin for positioning.

1 is a schematic perspective view of a connector and a mounting board to which the present invention is applied. It is the longitudinal cross-sectional view at the time of mounting the connector of Example 1, and a partially broken bottom view. It is the perspective view which decomposed | disassembled some positioning pins of Example 1. FIG. It is the longitudinal cross-sectional view and the partially broken bottom view when the connector of Example 1 is mounted. It is the perspective view which decomposed | disassembled some positioning pins of Example 2. FIG. It is the longitudinal cross-sectional view when the connector of Example 2 is mounted, and a partially broken bottom view. It is the longitudinal cross-sectional view and the partially broken bottom view when the connector of Example 3 is mounted.

Explanation of symbols

1 Connector (electronic component)
2 Mounting Board 11 Positioning Pin 12 Elastic Contact 13 Terminal 21 Positioning Hole 22 Wiring Land 111 Thermal Expansion Member (Position Restraining Member)
111A Thermal expansion member (position restraint member)
111B shape memory alloy wire (position restraint member)
112 Notch groove 112A Circumferential groove

Claims (6)

  A surface mount type electronic component mounted on a mounting board having a positioning hole and having a positioning pin that can be inserted into the positioning hole, wherein the positioning pin contacts the inner surface of the positioning hole when thermally deformed. A surface-mount type electronic component comprising a position restraining member for restraining the position of a pin.   The surface mount electronic component according to claim 1, wherein the position restraining member is a thermal expansion member that thermally expands when heated.   The surface mount electronic component according to claim 1, wherein the position restraining member is a heat deformable member that is thermally deformed when heated.   4. The surface-mount type electronic component according to claim 2, wherein the position restraining member is thermally expanded at a solder reflow temperature or is thermally deformed to contact the inner surface of the positioning hole. 5.   The surface mounting according to any one of claims 1 to 4, wherein the position restricting member is provided on a part of the circumference of the positioning pin, and abuts against a part of the inner peripheral surface of the positioning hole when deformed. Type electronic components. 5. The surface mounting type according to claim 1, wherein the position restraining member is provided over the entire circumference of the positioning pin, and abuts against the entire inner peripheral surface of the positioning hole when deformed. Electronic components.

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