CN1179235A - Press-fit connecting pin and electronic device using the same - Google Patents

Abstract

The present invention is directed to a small-size press-fit connecting pin which can be press-fitted and connected in the through-hole of a circuit board by means of a low insertion force, and an electronic device using this press-fit connecting pin. The press-fit connecting pin (10) has a shaft portion with a diameter of approximately 0.4 mm, and has a first section (42) and second section (43) (along the length of the shaft portion) whose length is less than the thickness of the circuit board (100) in which the through-hole (101) is formed. Projecting strips (45, 46) which run in the direction of length are formed on the outer surfaces of the respective sections (42 and 43). The projecting strips (45 and 46) formed on the first section (42) and second section (43) are formed in mutually different angular positions.

Description

Press-fit connection terminals and electronic devices using them

The present invention relates to a terminal capable of being press-fitted and connected to electrical terminals, particularly plated through holes, and electronic devices such as terminal grid arrays (PGAs), IC devices and electrical connectors or the like, wherein use the press-fit connection terminal.

Electronic circuit parts, which in use can be connected to a circuit board, such as PAGs, IC devices, electrical connectors, switches, etc. (hereinafter collectively referred to as "electronic devices"), have many terminals or terminals. The terminal may be connected to a conductive connection area of a circuit board or to a conductive trace in use.

In the case of such an electronic device, the number of terminals is increased and the terminals are mounted at a higher density (smaller pitch), so that the size of the electronic device is reduced and the performance of the device is improved. Soldering is a common technique used to effectively electrically connect the many high density terminals to the circuit board. However, in the case of high-density terminals, not only is soldering difficult, but there is also a problem of lowering reliability by soldering bridges and the like. Also, it is extremely difficult to remove the electronics once they are soldered. Therefore, maintenance and repair of the soldered device is difficult.

To overcome this soldering disadvantage, a direct electrical connection technique has been proposed, which is achieved by press-fitting the terminals into a circuit board with plated through holes. This technique has spread widely, especially in the field of communication equipment.

A compliant terminal called an ACTION PIN terminal has been commercially sold by AMP Corporation as a type of this press-fit connection terminal. The compliant terminal is constructed so that the cylindrical portions of the terminal can be cut axially and are mutually offset along the cut surfaces, as disclosed in U.S. Patent No. 4,186,982. Therefore, the terminal can be relatively smoothly press-fitted onto the inner wall of the plated through hole, so that a highly reliable electrical connection can be obtained and maintained with a large contact pressure without damaging the plating layer. Similar compliant terminals are also disclosed in Japanese Utility Model Application Publication No. 58-14683, and terminals split into three parts are disclosed in Japanese Utility Model Application Publication No. 60-45463 and elsewhere.

On the other hand, in Japanese Patent Application Publication No. 62-5575, Japanese Utility Model Application Publication No. 58-154572, Japanese Utility Model Application Publication No. 60-172370, Japanese Utility Model Application Publication No. 58-157972, Japanese Utility Model Application Publication No. 58-172881 and elsewhere disclose compliant or press-fit terminals that can be given a deformable cross-sectional shape by applying pressure or machining without shearing the cylindrical portion of the terminal.

The commonly used compliant terminals mentioned above are sufficient for the application of certain special occasions, and in the case of small-sized high-density terminals with extremely thin shaft bodies, that is, they have a diameter of about 0.4mm in accordance with the requirements of recent electronic devices, it is convenient to use them. extremely difficult or impossible. The reasons are as follows:

First, in the case of a compliant terminal in which the cylindrical portion is split into two or three parts as described above by cutting or offsetting the cylindrical portion, the processing cannot be applied to a thin pin having a diameter of about 0.4 mm.

Second, when a commonly used terminal that has been processed so that the cross-sectional shape of the terminal is deformable is used in a through hole having a diameter of about 0.4 mm, the amount of deformation is so small that an additional insertion force is required for press-fitting. Therefore, the terminal itself is subject to bending deformation. Also, the plating layer of the through-hole may be damaged, or, depending on the dimensional processing tolerances of the through-hole and the terminal, it may not be possible to obtain a very high-reliability electrical connection.

It is therefore an object of the present invention to provide a press-fit connection terminal [a] which can be relatively easily press-fitted into a through-hole having a relatively large dimensional tolerance, [b] which makes it possible to obtain a highly reliable electrical connection, And [c] It can be used in the case of small-sized high-density terminals.

Another object of the present invention is to provide an electronic device having many small-sized high-density press-fit connection terminals, and which has a small insertion force and highly reliable press-fit connection terminals.

In order to eliminate the shortcomings of the above-mentioned commonly used press-fit connection terminals and achieve the above-mentioned technical purpose, the press-fit connection terminal of the present invention is characterized in that the deformable protruding strips protruding from the radial structure are formed at different angles and positioned on the terminal at many different points on the cylinder section. Also, the press-fit connection terminal of the present invention is characterized in that the terminal basically has a circular cylindrical portion. The cylindrical portion has substantially parallel surfaces on opposite sides of the shaft on which the cylindrical portion is formed. A radially raised strip is formed on the central portion of the parallel surfaces, protruding beyond the circumference of the circular cylinder portion.

Furthermore, the electronic device of the present invention is characterized in that the device uses a plurality of press-fit connection terminals having the above-mentioned constitution, so that a high-reliability electrical connection with a plated through hole formed on a circuit board can be realized with a relatively small insertion force .

The preferred embodiment of the press-fit connection terminal of the present invention and the electronic device using the terminal will be described in detail with reference to the accompanying drawings, wherein the accompanying drawings:

Fig. 1 is a front view, which represents a preferred embodiment of the press-fit connection terminal of the present invention and the whole structure of the connection between the terminal and the circuit board;

Fig. 2 is a sectional view of an example of a press-fit connection part of the press-fit connection terminal shown in Fig. 1;

Fig. 3 is a cross-sectional view showing a situation in which the press-fit connection terminal of Figs. 1 and 2 is press-fitted into a through hole of a circuit board;

4 is a cross-sectional view of a first alternative embodiment of a terminal press-fit connection portion;

5 is a cross-sectional view of a second alternative embodiment of a terminal press-fit connection portion;

6 is a cross-sectional view of a third alternative embodiment of a terminal press-fit connection portion;

7 is a cross-sectional view of a fourth alternative embodiment of a terminal press-fit connection portion;

Figure 8 is a front view of the electronic device of the present invention;

FIG. 9 is a bottom view of the device of FIG. 8. FIG.

First, the entire configuration of a press-fit connection terminal constituting a preferred embodiment of the present invention will be described with reference to FIG. 1 . FIG. 1 is a side view of the press-fit connection terminal 10 . The press-fit connection terminal 10 is preferably made of a copper alloy such as zirconium copper alloy or the like, or of another conductive alloy such as one sold under the KOVAR ^(R) trade name. The entire shape of the terminal is substantially cylindrical. Terminal 10 has a large diameter flange portion 20, which is located approximately in the middle along the terminal; also, terminal 10 has a substantially uniform cylindrical portion 30 on one side of flange portion 20, and on the other side of flange portion 20 The press-fit connection portion 40 on the circuit board 100 can be press-fitted into the plated through hole 101 formed on the circuit board 100 . In this particular embodiment, the thickness of the circuit board 100 is approximately 2.0 mm, and the inner diameter of the through hole 101 is 0.45 ± 0.05 mm. The entire length of the press-fit connection terminal 10 is 4.8 mm, the length and diameter of the cylindrical portion 30 are 3.1 mm and 0.45 mm, respectively, the diameter of the flange portion 20 is 0.9 mm, and the length of the press-fit connection portion 40 is 1.7 mm. Of course, it should be noted that these sizes and shapes can be appropriately selected according to the intended use of the terminal.

The press-fit connection portion 40 constituting an essential part of the press-fit connection terminal 10 of the present invention will be described below. The press-fit connection portion 40 in this particular embodiment has [a] a tapered end portion 41, [b] a first segment 42 and a second segment 43 forming extensions of the end portion 41 each having a diameter of approximately 0.6 mm in length, and if necessary, [c] (eg) four radial ribs 44 formed on the press-fit connection portion side of the flange portion 20 .

The first section 42 and the second section 43 of the press-fit connection portion 40 have substantially the same shape, and each of them is formed with, for example, two raised strips 45 or 46 on the outer circumference of the terminal. The raised strips 45 and 46 of the first section 42 and the second section 43 are formed at different angular positions relative to each other; for example, the raised strips 45 and 46 in FIG. 1 are formed in a perpendicular relationship.

An example of the first section 42 of the press-fit connection portion 40 of the press-fit connection terminal 10 is shown in cross-section in FIG. 2 . The first segment 42 in this example has [a] a body or cylindrical portion 50 having circular arc-forming sections 51, 52 spaced about 0.4mm in diameter, and parallel surfaces 53, 54 spaced apart by a distance of 0.2mm, And [b] protrusions 55, 56 formed at almost the center of the two parallel surfaces 53, 54 and extending outward from these parallel surfaces 53, 54 in a substantially perpendicular direction (ie, radial direction). Protrusions 55, 56 are formed by bases 55a, 56a, which have a width of about 0.1 mm, and deformable portions 55b, 56b, which have a width of about 0.05 mm, and which extend outwardly from the tips of bases 55a, 56a. (These deformable portions are referred to below as "raised strips" because they correspond to raised strips 45, 46 in FIG. 1). The tips of the bases 55a, 56a are positioned on the circumference of a circle having a diameter of about 0.4mm, which is an inner circle having the same diameter as the circle formed by the arc-forming portions 51, 52 of the main body portion 50. Also, the tips of the raised strips 55b, 56b are positioned on the outer circumference having a diameter of about 0.56 mm and centered on the axis of the main body portion 50.

Next, the press-fit connection terminal 10 shown in FIGS. 1 and 2 will be described with reference to the cross-sectional view shown in FIG. 3 , which shows the terminal 10 press-fitted in the through hole 101 of the circuit board 100 . Also, in FIG. 3 , the first segment 42 is shown by a solid line, and the second segment 43 is shown by a dotted line, thereby showing the positional relationship between the two segments. Further, it is assumed that the sizes and shapes of the sections of the through-holes 101 of the circuit board 100 and the press-fit connection portions 40 of the press-fit connection terminal 10 are the same as those described in the above examples.

As shown in Figure 3, the inner circle (0.4mm) formed by the two arc-forming parts 51, 52 of the main body part 50 is smaller than the diameter (central value: 0.45mm) of the through hole 101, therefore, the main body can be inserted The portion 50 is not in contact with the inner wall of the through hole 101. However, since the tips of the raised bars 55b, 56b are positioned on the circumference of the above-mentioned outer circle, which has a diameter of 0.56mm, the raised bars 55b, 56b will contact the inner wall of the through hole 101 and deform. The amount of deformation depends on the dimensional relationship with the through hole 101 . Also, since the second section 43 of the press-fit connection part 40 is perpendicular to the first section 42 , the protruding strip 45 of the second section 42 also contacts and deforms with the inner wall of the through hole 101 .

Here, it should be noted that since the protruding strips of the press-fit connection terminal 10 are deformable, even if the plating layer of the through hole 101 is scraped off by the protruding strips 45, 46, the scraping only occurs at the total plating layer. Also, since the raised strips 45, 46 of the first segment 42 and the second segment 43 are offset from each other, there is no risk of damaging the via 101 (ie, no risk of loss of conductivity). Furthermore, it should also be noted that since the raised strips 45, 46 have a width of approximately 0.05 mm as described above, the required insertion force for inserting the press-fit connection terminal 10 into the through-hole 101 can be kept sufficient. at low values.

As shown in FIG. 1 , the flange portion 20 of the press-fit connection terminal 10 forms a stop surface by which the terminal 10 fits with the surface of the circuit board 100 . Also, when the terminal 10 is soldered to the circuit board 100 by surface mount technology (SMT) (i.e., reflow soldering technology), the radial rib 44 on the outer surface of the flange portion 20 can provide a gas leakage path, making it possible to obtain Good electrical connection. However, the radial rib 44 is not an essential part of the present invention, and it may be omitted depending on the specific application of the terminal 10 .

The raised strips 45, 46 of the press-fit connection terminal 10 shown in FIGS. 1 and 2 are radially formed with respect to the axis of the main body portion 50; The process in the hole 101 undergoes minor deformation and bites into the inner wall of the through-hole 101 like a knife edge. However, the raised strips 45 , 46 are not necessarily limited to radially extending, eg raised strips extending in a direction perpendicular to the parallel surfaces 53 , 54 . Alternative embodiments of raised strips 45, 46 will be described with reference to FIGS. 4-7.

In the alternative embodiment 142, 242 shown in FIGS. 4 and 5, the main body portions 150, 250 and base portions 55a, 56a are the same size and shape as the corresponding portions shown in FIG. However, these examples are characterized in that the raised strips 45, 46 (not shown) are angled from the radial direction at a specific angle such that the cross-sectional shape of the entire raised strip is about an "f" shape. In particular, the raised strips shown in FIG. 4 have an inclination angle of about 45 degrees relative to the radial direction, while the raised strips shown in FIG. ). In both alternative embodiments 142, 242, the tips of the raised strips are positioned on the outer circumference of the diameter 0.56 mm in the case of the raised strips in FIG. 2 . It should be noted that in these two deformation examples, the raised bar can be deformed relatively easily, and when the terminal 10 is press-fitted into the through-hole 101 of the circuit board 100, the tip of the raised bar will receive the contact along the through-hole. The inner wall of the hole 101 is bent inward by the force of the tip from the outer circumference. Therefore, the following advantages can be obtained: that is, the insertion force required for inserting the press-fit connection terminal 10 into the through hole 101 is small, so that the plating layer on the inner wall of the through hole 101 is hardly damaged; Layers have good electrical connections that exhibit variations through dimensional tolerances.

Next, an alternative embodiment 342, 442 shown in Figures 6 and 7 is described which has slightly different dimensions and shapes than the embodiment of Figures 4 and 5 described above. Here, the arc-forming surfaces 51', 52' of the body parts 350, 450 are positioned on the inner circumference having a diameter of 0.42 mm, and the distance between the parallel surfaces 53', 54' is 0.3 mm.

In the press-fit connection terminal shown in FIG. 6, bases are formed on central portions of the parallel surfaces 53', 54', and the tips of these bases are positioned on the circumference of the above-mentioned inner circle. A raised strip 45 is formed radially on the center of each base tip, however, a semicircular cut 45a (ie, having a radius of about 0.015 mm) is formed on the root on the right side of each raised strip 45 . As a result of the deformation of the notch 45a, the force that bends the protruding strip 45 toward the side where the notch 45a is formed, that is, the force that bends in the clockwise direction in these drawings, acts when the terminal 10 is press-fitted into the through hole 101. On the raised strip 45. Therefore, effects similar to those in FIGS. 4 and 5 can be obtained.

The embodiment shown in Figure 7 is similar to the embodiment shown in Figure 6, however, this embodiment differs from the embodiment shown in Figure 6 in that the bases 55a, 56a are offset on one side (i. the opposite side of that side). As a result of this shape, the raised strip 45 has a chamber or space for further inclination in a clockwise direction. Therefore, the raised strip 45 is sufficiently bent even in the case of a relatively small-diameter through-hole 101 , so that press-fitting and connection can be performed relatively smoothly without any major damage to the through-hole 101 .

The press-fit connection terminal 10 of the present invention has been described in detail above along with various alternative examples. However, the present invention is not limited to these embodiments; it goes without saying that various modifications and variations are possible depending on specific applications without departing from the spirit of the present invention.

An electronic device using the press-fit connection terminal 10 of the present invention will be briefly described below with reference to FIGS. 8 and 9 . FIG. 8 is a side view of the electronic device 200, and FIG. 9 is a bottom view thereof. Electronic device 200, shown here as an example only, is a device commonly referred to as a "P-PGA" (Plastic Terminal Grid Array). In this electronic device 200, various types of semiconductor integrated circuits (ICs) and the like can be mounted and connected on the surface of a plastic substrate, and the entire device can be encapsulated with a plastic material such as epoxy resin. Many press-fit connection terminals 10 may be arranged in a matrix on the bottom surface of the main body 201 of the electronic device 200 .

Each press-fit connection terminal 10 may be any of the terminals described with reference to FIGS. 1 to 7 . The cylindrical portion 30 of the terminal 10 can be connected to the conductive contact on the plastic substrate by soldering or similar techniques, so that the terminal 10 can be electrically connected with the above-mentioned various IC specific circuits. In such an electronic device having many interconnection terminals, it is highly desirable to use the press-fit connection terminal 10 for ease of mounting and connection to a circuit board, among other purposes. In the past, there was such a need, but no electronic device was proposed to specifically realize this connection. By using the press-fit connection terminal 10 described above, this connection is made possible for the first time. Also, it is desirable that the press-fit connection terminal 10 is made of a good conductor of electricity and heat, such as copper alloy or the like.

As shown above, the use of the press-fit connection terminal of the present invention makes it possible, that is, due to the specific structure of the terminal, the terminal can be inserted into the through hole of the circuit board with a small insertion force, so that the impact on the inner wall of the through hole can be reduced. damage to the plating on the Also, a sufficiently reliable electrical connection to the vias can also be obtained. Furthermore, the terminal of the present invention can also be used in many cases where the through-holes included therein have a relatively large dimensional tolerance (eg, ±0.05 mm). Therefore, the present invention has an obvious advantage that it can realize the connection of an electronic device having a large number of terminals mounted at a high density to a circuit board.

Claims (4)

1, a kind of splicing ear that is press-fitted, it can press fit on the circuit board in the formed through hole, and it has the colonnette body portion in order to be electrically connected, and the described splicing ear that is press-fitted is characterised in that:

Be formed with deformable raised item with different angle mutually on described cylinder part on many separated positions, it is to stretch out with form substantially radially, and described raised item so forms, and makes them can contact the inwall of described through hole.

2, a kind of splicing ear that is press-fitted, it can press fit on the circuit board in the formed electroplating ventilating hole, and it has almost circular cylinder part in order to be electrically connected, and the described splicing ear that is press-fitted is characterised in that:

The both sides of the described cylinder part in fixed on the axle of described cylinder part form substantially parallel surface, and are to form in the almost central authorities of described parallel surfaces with the raised item that radial form is stretched out.

3, a kind of electronic device, it has many splicing ears that are press-fitted, and it can be press-fitted and be connected in the through hole, and described electronic device is characterised in that:

The described splicing ear that is press-fitted has the described structure of claim 1.

4, a kind of electronic device, it has many splicing ears that are press-fitted, and it can be press-fitted and be connected in the through hole, and described electronic device is characterised in that:

The described splicing ear that is press-fitted has the described structure of claim 2.

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