JPH0473271B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Technical Field of the Invention The present invention relates to a drive terminal that is press-fitted into a through hole of a printed circuit board and is soldered or electrically connected and fixed.

(b) Background of the technology Traditionally, drive terminals for inputting and outputting external signals to circuits formed on printed circuit boards were not able to provide sufficient electrical connection and fixing strength just by being driven in, so they had to be soldered after being implanted. A method of doing dips was generally practiced. However, although this method provides sufficient electrical connection and fixing strength, it requires a solder dip process and the number of man-hours involved.

Therefore, a plug-in terminal that does not require soldering has appeared and has come into use.

(c) Prior Art and Problems Figure 1 is a perspective view (a) showing a first drive-in terminal with a conventional configuration, an enlarged cross-sectional view (b) in the direction of arrow A, and an enlarged cross-sectional view (c) in the direction of arrow B. They are a perspective view (a) and an enlarged cross-sectional view (b) in the direction of arrow C, showing a second drive-in terminal having a conventional configuration.

In FIG. 1, a drive terminal 1 is made of a conductive material with spring properties such as phosphor bronze, and has a pin-shaped main body 4 having a contact portion 2 and a wire wrap portion 3 at both ends, and a locking portion 5 and a pin-shaped body 4 in the middle portion. It is constructed by integrally forming the joint portion 6. The joint portion 6 elastically connects a pair of pressure contact portions 7 through a connection portion 8, and the connection portion 8 is formed thinner than the pressure contact portion 7 at opposing recesses 9 and 10.

In FIG. 2, the drive terminal 11 is made of a conductive material with spring properties such as phosphor bronze, and has a locking part 15 and a pin-shaped main body 4 having a contact part 12 and a wire wrap part 13 at both ends. It is constructed by integrally forming the joint portion 16. The joint portion 16 is formed by elastically connecting a pair of pressure contact portions 17 with a connecting portion 18.

In the drive terminal configured in this way, the joint part is press-fitted into the through hole of the printed circuit board, and the locking part is brought into contact with the top surface of the printed circuit board. In this case, ideally, the conductor of the through hole It is desirable that the terminal be press-fitted without cutting the layer, with a small press-in force and a large pull-out force (terminal holding force). As shown in the cross-sectional views of two examples,
If a partial gap 23, 24 is formed between the end face 21 of the pressure welding part and the inner surface of the through hole 22, or a partial cut 25 occurs in the through hole 22 at the corner of the pressure welding part, the terminal may be pressed with a pressure force of approximately 12 kg. The removal force when press-fitting is about 5 to 6 kg, and there has been a demand for improvement.

(d) Object of the Invention The object of the present invention is to provide a driving terminal in which the above-mentioned problems are improved, based on the results of examining the shape of the connecting portion of the driving terminal when it is press-fitted into a through hole and the state in which it is press-fitted. That's true.

(e) Structure of the invention
The connecting part, the locking part as a stopper to the other side of the printed board, and the contact part of the pin-shaped body are made of a spring conductive material integrally formed, and the locking part has a shape that projects from the side surface of the pin-shaped body. The joint part is composed of a pair of pressure contact parts and a connecting part that protrude outward from the side surface of the pin-shaped body, and a recess is formed between the joint part and the locking part to prevent contact with the through hole. The outer shape in the long axis direction is approximately oval in plan view,
The outer shell of both ends is tapered with respect to the pin-shaped body, and the width end of the pressure welding part has an appropriate roundness, and the connecting part elastically connects the pressure welding parts, and one side is within the width of the pressure welding part. It is a gentle V-shaped surface with the bottom part extending from the other side beyond the center line of the width of the pressure welding part, and the other side having both ends tapered towards the inside of the width of the pressure welding part and the center part being within the width of the pressure welding part. It becomes an arcuate surface outward, and the thickness between the bottom of the V-shaped surface and the apex of the arcuate surface is approximately 1/1 of the width of the pressure welding part.
This is achieved by a drive-in terminal characterized in that it is selected from No. 3.

(f) Embodiments of the invention Examples of the invention will be described below with reference to the drawings.

FIG. 4 is a plan view of a drive terminal according to an embodiment of the present invention;
Fig. 5 is a sectional view for sequentially explaining the process of press-fitting the drive-in terminal into a printed circuit board, Fig. 6 is a press-in force diagram during the press-fitting, and Fig. 7 is a diagram showing how the drive-in terminal is inserted into the through hole. FIG. 3 is a cross-sectional view of a press-fitted terminal joint portion.

In FIG. 4, the drive terminal 31 is made of a conductive material with spring properties such as phosphor bronze, and has a locking part 35 and a pin-shaped main body 34 having a contact part 32 and a wire wrap part 33 at both ends. The joint portion 36 is integrally formed, and the joint portion 36
A pair of press-contact parts 37 are elastically connected by a connecting part 38 having an arc-shaped cross section.

Note that the joining portion 36 and the connecting portion 38 are approximately oval in plan view, and due to the oval shape, a recess 43 is formed between the joining portion 36 and the locking portion 35 to avoid contact with the inner wall of the through hole. ing. On the other hand, as shown in FIGS. 4B and 4C, the connecting portion 38 is composed of a gentle V-shaped surface 39 on one side and a combination surface 40 of a tapered surface and an arcuate surface on the other side.

FIG. 5 is a diagram showing the process of press-fitting the drive-in terminal 31 into a through-hole. In FIG. 6, which shows changes in the press-in force at that time, the horizontal axis indicates contact between the tip shoulder of the joint portion 36 and the through-hole. The displacement (stroke) after that, the vertical axis is the press force, and the solid line P is the drive terminal pressure input characteristic.

In FIGS. 5 and 6, the wire wrap portion 3
Through hole 42 of printed board 41 from the tip of 3
When the drive terminal 31 is inserted into the area, the tip shoulder portion 36a of the joint portion 36 comes into contact with the through hole 42 as shown in _FIG . It corresponds to characteristic P and gradually increases. Therefore, when the insertion is continued further, when the straight portion of the joint portion 36 comes into contact with the through hole 42 over almost its entire length as shown in _FIG . The increase in P decreases and an almost flat portion is formed.

Then, when the insertion is further continued, the rear end shoulder 36b of the joint portion 36 comes into contact with the through hole 42 and the contact becomes deeper, as shown in FIG. The pressing force in the area where the press stops when it hits corresponds to the characteristic P in the displacement area _p3 in FIG. 6, and after gradually increasing, becomes almost flat (or tends to decrease slightly) and stops.

In such a characteristic p, the flat portion (or reduction in pressing force) in the displacement region p ₃ corresponds to the driving terminal 3
This is realized by making the joint portion 36 of 1 substantially oval in plan view, that is, by connecting the end near the locking portion 35 to the pin-shaped main body 34 via an inclined portion,
In the conventional drive-in terminal shown in FIGS. 1 and 2, the joint part is connected to the locking part with a wider width than the pin-shaped main body, so that the pressing force corresponding to the displacement area _p3 is applied to the front area p. The pressure increased following the pressure increase characteristic of ₂ .

Therefore, as shown in FIG. 9, the taper α ₁ at both ends of the joint portion 36 is approximately 15 degrees, the taper α ₂ at both ends of the connecting portion 38 is approximately 20 degrees, and furthermore, the longitudinal ends of the connecting portion 38 are When the drive terminal 31 whose rising angle α ₃ is approximately 50 degrees as shown in Figure 4 C is pressed into the through hole 42 with a pressure of approximately 12 kg, the removal force is 7 kg.
As a result, we were able to increase the removal force (holding force) by more than 15% compared to the conventional drive terminal that was press-fitted with the same pressure.

On the other hand, as shown in FIG. 7, the joint portion 36 press-fitted into the through hole 42 has an outer end surface of the joint portion 36 (pressure contact portion 37) extending over the entirety of the through hole 4.
It is adapted to be pressed against the inner wall of No. 2. However, such a press-contact state depends on how the pair of press-contact parts 37 integrated via the connection part 38 behave within the through-hole 42, that is, how the plastic deformation strength of the connection part 38 and the inside of the through-hole 42 behave. How the pair of press-contact parts 37 are displaced relative to each other has a great influence.

Therefore, the inventors determined that the cross-sectional dimensions of the joint portion 36 are as shown in FIG.
t ₀ , the thickness of the central part of the arc-shaped connecting portion 38 is t ₁ , the illustrated lower corner 37a of the pressure contact portion 37 slides along the inner wall of the through hole, and the illustrated upper corner 3
7b approaches in the opposite direction (inward), and the study focused on the possibility that plastic deformation of the connecting portion 38 should occur so that the lower corner 37a of the same name is deformed so as to expand outward.

As a result, in FIG. 8, the thickness t ₁ at the center of the arc-shaped cross section in the width direction of the joint portion 36 is approximately 1/3 of the thickness t ₀ of the pressure welding portion 37, and By making the deviation δ between the center line and the central upper part of the connecting portion 38 at least 1/10 of the pressure welding portion thickness t ₀ , the deformation accompanied by the sliding is realized, and furthermore, each cross-sectional corner portion is appropriately shaped. roundness (e.g. R0.1)
By adding this, the insertion of the drive terminal can be done smoothly and without damaging the through hole.

(g) Effects of the Invention As explained above, according to the present invention, the press-fitting of the drive terminal is facilitated and its holding force is increased, and the conductor layer of the through-hole is not damaged during the press-fitting, so that the drive terminal can be easily pressed into the drive terminal. The effect of improving the reliability of circuit connections is extremely large.

[Brief explanation of the drawing]

Figure 1 is a diagram for explaining a first drive terminal with a conventional configuration, Figure 2 is a diagram for explaining a second drive terminal with a conventional configuration, and Figure 3 is a diagram for explaining a drive terminal with a conventional configuration. 4 is a cross-sectional view showing the press-fitting state of the terminal, FIG. 4 is a diagram for explaining a drive terminal according to an embodiment of the present invention, and FIG. 5 is a process of press-fitting the drive terminal shown in FIG. 4 into a printed board. 6 is a press-in force diagram when the drive terminal shown in FIG. 4 is press-fitted into the through hole of the printed circuit board,
FIG. 7 is a sectional view of the terminal joint portion where the drive terminal shown in FIG. 4 is press-fitted into the through hole, and FIG. 8 is a diagram for explaining the main dimensions of the drive terminal joint portion shown in FIG. 4. , FIG. 9 is a plan view of the drive terminal joint shown in FIG. 4. In the figure, 1, 11, 31 are drive terminals,
4, 14, 34 are pin-shaped pairs, 5, 15, 35 are locking parts, 6, 16, 36 are joint parts, 7, 17,
37 is a pressure contact part, 8, 18, 38 is a connecting part, 22,
42 is a through hole, 43 is a recess that escapes contact with the inner wall of the through hole, α ₁ is a taper at both ends of the joining part, α ₂ is a taper at both ends of the connecting part, α ₃ is the longitudinal end of the connecting part t ₀ is the thickness of the pressure welding part, and t ₁ is the thickness of the central part of the connecting part.

Claims (1)

[Claims] 1 A spring conductive wire in which a wire wrap part of a pin-shaped body press-fitted into a through-hole of a printed board, a connecting part, a locking part as a stopper to the other side of the printed board, and a contact part of the pin-shaped body are integrally formed. The locking part has a shape that protrudes from the side surface of the pin-shaped body, and the joint part is composed of a pair of pressure-welding parts and a connecting part that protrude outward from the side surface of the pin-shaped body. A recess is formed between the parts to prevent contact with the through hole, and the outer shape of the joint part in the longitudinal direction is approximately oval in plan view, and the outer shell of both ends is tapered with respect to the pin-shaped body, so that the pressure welding part The width end portion has an appropriate roundness, and the connecting portion elastically connects the pressure welding portions, and one side thereof has a gentle V into the width of the pressure welding portion.
In terms of shape, the bottom part is the other side beyond the center line of the width of the pressure welding part, the other side is a tapered shape surface on both ends of the width of the pressure welding part inward, and the center part is a circular arc shape outward within the width of the pressure welding part. A driving terminal characterized in that the thickness between the bottom of the V-shaped surface and the apex of the arc-shaped surface is selected to be approximately 1/3 of the width of the pressure welding part.