Press-fit terminal and connector assembly

Abstract

To provide a press-fit terminal and a connector assembly having a more stable holding force than a press-fit terminal having an oval outer shape.SOLUTION: A press-fit terminal 200 includes a press-fit portion 208 having a pair of elastically deformable legs 216, 218 of a double-supported beam structure that are electrically connected to the conductive material on the inner surface when inserted into a through-hole 310 of a printed wiring board 300 and are formed so as to be connected to each other at fixed ends 210, 212 on the front and rear sides in the insertion direction relative to the through-hole 310, thereby forming a slit 214, and each of the pair of elastically deformable legs 216, 218 has two bulge portions 224, 226, 228, 230 on the front and rear sides in the insertion direction that bulge out in the width direction more than the intermediate portions 220, 222, and the widths from the intermediate portions 220, 222 to the two bulge portions 224, 226, 228, 230 each change continuously, resulting in a tapered shape.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a press-fit terminal that is inserted into a through-hole formed in a printed wiring board to be mechanically held to the board and electrically connected to a printed circuit, and to a connector assembly. [Background technology]

[0002] Press-fit terminals do not require a soldering process and are mechanically held to the board and electrically connected to the printed wiring board by being pressed into a through-hole formed in the printed wiring board, and are used in various electronic devices.

[0003] For example, Patent Document 1 below discloses a press-fit terminal for insertion into a through-hole formed in a substrate, which has a pair of elastically deformable legs with a double-supported beam structure connected to each other at fixed ends so as to surround a roughly elliptical slit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-053082 Summary of the Invention [Problem to be solved by the invention]

[0005] The press-fit terminal disclosed in Patent Document 1 is held to the printed wiring board by the elastic force of the elastically deforming legs of the terminal and the frictional force between the outer surface of the terminal and the inner surface of the through-hole formed in the board. This holding force can vary depending on the type of plating on the inner surface of the through-hole, the material of the board, and the structure of the board, such as a four-layer structure or an eight-layer structure.

[0006] Therefore, it is desirable to provide a press-fit terminal that has a stable holding force and is less susceptible to the influence of the type of plating on the inner surface of the through-hole, the material of the substrate, and the structure of the substrate when compared when inserted into a substrate of the same pressure and a through-hole of the same diameter.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a press-fit terminal and a connector assembly that have a more stable holding force than press-fit terminals having a so-called elliptical or egg-shaped outer shape. [Means for solving the problem]

[0008] In order to solve the above problem, one aspect of the present invention is to a press-fitting portion including a pair of elastically deformable legs having a double-supported beam structure that, when inserted into a through-hole of a printed wiring board, is electrically connected to a conductive material on an inner peripheral surface of the through-hole, and is formed so as to be connected to each other at fixed ends on the front and rear sides in the insertion direction into the through-hole, thereby forming a slit; This press-fit terminal has a pair of elastically deformable legs, each of which has two bulging portions that bulge out more in the width direction than the middle portion on the front and rear sides in the insertion direction into the through hole, and the width from the middle portion to the two bulging portions changes continuously, resulting in a tapered shape.

[0009] In one aspect of the present invention, the slit is longer on the front side and the rear side than the two bulging portions.

[0010] In one aspect of the present invention, the length of the slit in the insertion direction is longer than the length of the through hole.

[0011] In one aspect of the present invention, the shape of the slit corresponds to the shape of the pair of elastically deformable legs, and the front and rear sides in the insertion direction are wider in the width direction than the middle part, so that the slit is an elliptical shape with a narrowed center.

[0012] Another aspect of the present invention is a connector assembly including a press-fit terminal of any of the above aspects and an insulating retaining member, wherein the press-fit terminal further has a fixing portion, and the fixing portion is fixed to the retaining member. [Effects of the Invention]

[0013] According to one aspect of the present invention, it is possible to provide a press-fit terminal that has a more stable holding force than a press-fit terminal having a so-called elliptical or egg-shaped outer shape.

[0014] Furthermore, according to another aspect of the present invention, the two bulging portions can provide a greater holding force to the printed wiring board from the front and rear sides of the through hole.

[0015] Furthermore, according to another aspect of the present invention, when the press-fit terminal is inserted into the through-hole, the two bulges can be sufficiently elastically deformed inward, thereby preventing excessive insertion force from being applied to the substrate material surrounding the through-hole.

[0016] According to another aspect of the present invention, when the press-fit terminal is inserted into the through-hole, the press-fit terminal can be sufficiently elastically deformed inward at both the front and rear sides in the insertion direction into the through-hole, thereby preventing excessive insertion force from being applied to the board material around the through-hole.

[0017] According to one aspect of the present invention, it is possible to provide a connector assembly having press-fit terminals that have a more stable holding force than press-fit terminals having a so-called elliptical or egg-shaped outer shape. [Brief explanation of the drawings]

[0018] [Figure 1]FIG. 1(A) shows an external perspective view of a press-fit terminal in one embodiment, FIG. 1(B) shows an elevation view of the press-fit terminal of FIG. 1(A) when viewed from the front side in the thickness direction, and FIG. 1(C) shows an elevation view of the press-fit terminal of FIG. 1(A) when viewed from one side in the width direction. [Figure 2] FIG. 2 is an enlarged view of part II in FIG. 1(B). [Figure 3] Figure 3(A) is a cross-sectional view of a press-fit terminal in one embodiment cut by an imaginary plane extending in the width direction, showing the state where it has begun to be inserted into a through-hole of a printed wiring board; Figure 3(B) is a cross-sectional view showing the state where the press-fit terminal has been further inserted into the through-hole from the state shown in Figure 3(A); and Figure 3(C) is a cross-sectional view showing the state where the press-fit terminal has been completely inserted into the through-hole. [Figure 4] FIG. 4(A) is a cross-sectional view taken along an imaginary plane extending in the width direction, showing a press-fit terminal inserted into a through-hole of a printed wiring board having a thickness different from that of the printed wiring boards shown in FIGS. 3(A) to 3(B), and FIG. 4(B) is a view showing, for comparison, a press-fit terminal inserted into a printed wiring board having the same thickness as that of FIG. 3(C). [Figure 5] FIG. 5(A) is an external perspective view of a header connector in one embodiment, and FIG. 5(B) is an elevation view of the header connector of FIG. 5(A) as seen from the front side in the thickness direction of the press-fit terminal. [Figure 6] FIG. 6 is a partial cross-sectional view in which a part of the header housing is cut away so that the inside of FIG. 5(B) can be seen. [Figure 7] Figure 7(A) shows an external perspective view of a modified header connector, Figure 7(B) is an elevational view of the header connector of Figure 7(A) when viewed from one side in the width direction of the press-fit terminal, and Figure 7(C) is an elevational view of the header connector of Figure 7(A) when viewed from one side in the thickness direction of the press-fit terminal. DETAILED DESCRIPTION OF THE INVENTION

[0019] A press-fit terminal 200 and a header connector 10 according to an embodiment will be described with reference to the drawings. Note that the following embodiment is an example of the press-fit terminal and connector assembly of the present invention, but the present invention is not limited thereto. The present invention should be equally applicable to other types of press-fit terminals and connector assemblies as defined in the claims.

[0020] The press-fit terminal 200 is formed by punching out a metal plate, such as a stainless steel, iron-nickel alloy, copper, or copper alloy plate, and its surface is plated with tin or the like. As shown in Figures 1(A) to 1(C) and 2, the press-fit terminal 200 includes a contact pin 204, a shoulder portion 206, and a press-fit portion 208.

[0021] In the following description, the side in the direction in which press-fit terminal 200 is inserted into printed wiring board 300 (described later) will be referred to as the rear side or top (or upper side), and the opposite side will be referred to as the front side or bottom (lower side). Also, the side perpendicular to the up-down direction will be referred to as the width direction, and the direction perpendicular to both the up-down direction and the width direction will be referred to as the thickness direction.

[0022] The contact pin 204 is a long, straight member that extends upward from a shoulder 206, and is connected to a female contact (not shown) of a mating connector.

[0023] Shoulder portion 206 is formed below contact pin 204, protruding symmetrically in the width direction with respect to the axis of press-fit terminal 200. This shoulder portion 206 is the portion that receives the pressing force from the underside of a press-fitting tool or a press-fitting jig when press-fit portion 208 is inserted into through-hole 310 of printed wiring board 300 (see FIGS. 3(A) to 3(C)).

[0024] Press-fit portion 208 is a portion that, when inserted into through-hole 310 of printed wiring board 300, is electrically connected to the conductive material on the inner circumferential surface of through-hole 310. Press-fit portion 208 has a lower fixed end 210 that is the fixed end on the front side in the insertion direction into through-hole 310, and an upper fixed end 212 that is the fixed end on the rear side. Press-fit portion 208 is formed so that lower fixed end 210 and upper fixed end 212 are connected to each other, and is thus provided with a pair of elastically deformable legs 216, 218 having a doubly supported beam structure that form slit 214, also called a needle eye.

[0025] Each of the elastically deformable legs 216, 218 has two bulging portions 224, 226, 228, 230 that bulge outward in the width direction from the intermediate portions 220, 222 on the front and rear sides in the insertion direction into the through hole 310. That is, as shown in FIG. 2 , the width W1 between the intermediate portions 220, 222 is smaller than the width W2 between the lower bulging portions 224, 226 and smaller than the width W3 between the upper bulging portions 228, 230. Note that the width W2 between the lower bulging portions 224, 226 and the width W3 between the upper bulging portions 228, 230 may be the same or different. Furthermore, the width W2 between the lower bulging portions 224, 226 and the width W3 between the upper bulging portions 228, 230 are larger than the diameter of the through hole 310 to be inserted.

[0026] Furthermore, the widths from the intermediate portions 220, 222 to the lower bulging portions 224, 226 change continuously, forming a tapered or curved (or curved) shape. Similarly, the widths from the intermediate portions 220, 222 to the upper bulging portions 228, 230 change continuously, forming a tapered or curved (or curved) shape.

[0027] The vertical length of the slit 214 is longer toward the front in the insertion direction, i.e., downward, than the lower bulges 224, 226, and is longer toward the rear in the insertion direction, i.e., upward, than the upper bulges 228, 230. That is, the distance L1 from a position of the slit 214 corresponding to the middle portions 220, 222 of the elastically deforming legs 216, 218 to the lower end 232 of the slit 214 is longer than the distance L2 from the middle portions 220, 222 to the lower bulges 224, 226. Similarly, the distance L3 from a position corresponding to the middle portions 220, 222 of the elastically deforming legs 216, 218 to the upper end 234 of the slit 214 is longer than the distance L4 from the middle portions 220, 222 to the upper bulges 228, 230. Therefore, the vertical length (L1+L3) of slit 214 is longer than the length (L2+L4) between two bulging portions 224-230. Furthermore, the vertical length (L1+L3) of slit 214 is longer than the length of through-hole 310 into which press-fit terminal 200 is inserted, i.e., the thickness of printed wiring board 300 in which through-hole 310 is formed.

[0028] Furthermore, the shape of slit 214 corresponds to the outer shape of elastically deformable leg portions 216, 218, and is oval with a narrowed center, with the front and rear sides in the insertion direction into the through-hole being wider than the middle portion. That is, width W4 of the middle portion of slit 214 is smaller than maximum width W5 on the front side in the insertion direction, i.e., the lower side, and maximum width W6 on the rear side in the insertion direction, i.e., the upper side. Note that maximum width W5 on the lower side and maximum width W6 on the upper side may be the same or different.

[0029] A method for mounting the press-fit terminal described above on a printed wiring board 300 will be described with reference to FIGS. 3A-3C. As shown in the cross-sectional view of FIG. 3A, a through-hole 310 is formed in the printed wiring board 300. The printed wiring board 300 is formed, for example, of a glass epoxy board called FR-4 (Flame Retardant Type 4), a standard Tg board, or a high Tg board. The printed wiring board may have a multi-layer structure, such as four or eight layers. The inner surface of the through-hole 310 is plated. The plating type is, for example, tin, silver, or copper preflux.

[0030] 3(A), first, press-fit terminal 200 held by a press-fit tool or press-fit jig (not shown) is inserted into through-hole 310 formed in printed wiring board 300. Then, the tapered portions below lower bulges 224, 226 of elastically deforming legs 216, 218 come into contact with upper end portion 314 of through-hole 310.

[0031] When the press-fit terminal 200 is pressed downward toward the printed wiring board 300 together with the press-fit tool, the underside of the press-fit tool presses the shoulder portion 206 of the press-fit terminal 200, thereby applying a further downward pressing force to the press-fit portion 208.

[0032] The press-fit portion 208 moves downward against the resistance force that the upper end portion 314 of the through-hole 310 exerts on the elastically deforming legs 216, 218. As a result, the elastically deforming legs 216, 218 elastically deform inward in the width direction, allowing the lower bulging portions 224, 226 to enter the through-hole 310 as shown in FIG. 3(B), and the press-fit portion 208 moves downward within the through-hole 310.

[0033] At this time, the shape of slit 214 is an ellipse with a narrowed center that corresponds to the outer shape of elastically deforming leg portions 216, 218, and the length of slit 214 is longer than the thickness of printed wiring board 300, so that lower bulges 224, 226 elastically deform flexibly inward in the width direction. This prevents excessive board insertion force from being applied to upper end portion 314 of through hole 310, preventing damage to the board.

[0034] 3(C), when the press-fit portion 208 is moved further downward, the lower bulges 224, 226 of the elastically deformable legs 216, 218 pass through the lower end portion 312 of the through-hole 310 and spread outward in the width direction. At this time, the upper bulges 228, 230 of the elastically deformable legs 216, 218 are located above the upper end portion 314 of the through-hole 310.

[0035] As described above, the widths of the elastically deformable legs 216, 218 from the middle portions 220, 222 to the lower bulges 224, 226 and the upper bulges 228, 230 are tapered so that they change continuously. Therefore, the lower end portion 312 of the through hole 310 is pressed by the tapered portions between the middle portions 220, 222 of the elastically deformable legs 216, 218 and the lower bulges 224, 226. In addition, the upper end portion 314 of the through hole 310 is pressed by the tapered portions between the middle portions 220, 222 of the elastically deformable legs 216, 218 and the upper bulges 228, 230.

[0036] That is, the upper end portion 314 and the lower end portion 312 of the through-hole 310 are gripped and sandwiched between the lower bulges 224, 226 and the upper bulges 228, 230 of the elastically deformable legs 216, 218. The upper bulges 228, 230 and the lower bulges 224, 226 of the elastically deformable legs 216, 218 exert a gripping force that sandwiches and holds down the printed wiring board 300, so that the press-fit terminal 200 is stably held in the through-hole 310.

[0037] Furthermore, if an attempt is made to move press-fit portion 208 of press-fit terminal 200 further downward in this state, upper bulges 228, 230 are wider than the diameter of through-hole 310, and a greater load is required to insert press-fit terminal 200 into through-hole 310. Furthermore, if an attempt is made to pull press-fit portion 200 upward in this state, lower bulges 224, 226 must be elastically deformed inward in the width direction, requiring the application of a greater pulling force. Therefore, it is possible to ensure a holding force for press-fit terminal 200 in both the insertion direction and removal direction relative to through-hole 310 of printed wiring board 300.

[0038] FIG. 4(A), like FIG. 3(C), is a cross-sectional view taken along an imaginary plane extending in the width direction, showing the press-fit terminal 200 inserted into the through-hole 310A of the printed wiring board 300A. However, the thickness T2 of the printed wiring board 300A in FIG. 4(A) is thinner than the thickness T1 of the printed wiring board 300 in FIGS. 3(A)-3(C). For comparison, FIG. 4(B) shows the press-fit terminal 200 inserted into a printed wiring board 300 having the same thickness as the printed wiring board 300 in FIGS. 3(A)-3(C). As is clear from a comparison of FIGS. 4(A) and 4(B), the widths of the elastically deformable legs 216, 218 are tapered, changing continuously from the middle portions 220, 222 to the lower bulges 224, 226 and the upper bulges 228, 230. 4(A), lower end portion 312A of through hole 310A is pressed by the tapered portions between middle portions 220, 222 of elastically deforming legs 216, 218 and lower bulging portions 224, 226. Also, upper end portion 314A of through hole 310A is pressed by the tapered portions between middle portions 220, 222 of elastically deforming legs 216, 218 and upper bulging portions 228, 230.

[0039] That is, even if the board thicknesses are different, lower end portion 312A and upper end portion 314A of through-hole 310A are gripped and sandwiched between lower bulges 224, 226 and upper bulges 228, 230 of elastically deforming legs 216, 218. Therefore, press-fit terminal 200 is stably held within through-hole 310A.

[0040] [Variation 1] In the above embodiment, an example has been described in which the press-fit terminal 200 is inserted individually into the through-holes 310, 310A of the printed wiring boards 300, 300A using a press-fit tool or a press-fit jig. However, as shown in the following Modification 1, it may be configured to be incorporated into the header connector 10. In Modification 1, the same components as those in Embodiment 1 will be described using the same reference numerals.

[0041] As shown in Figures 5(A) and 5(B), the header connector 10 includes a header housing 100 and a plurality of press-fit terminals 200A fixed to the header housing 100. In the first modification, ten press-fit terminals 200A are fixed to the header housing 100, but the number of press-fit terminals 200A fixed to the header housing 100 may be any number greater than one, and may even exceed ten. The press-fit terminal 200A of the first modification has substantially the same configuration as the press-fit terminal 200 of the first embodiment, except that, as shown in Figure 6, a fixing portion 202 is provided between a shoulder portion 206 and a press-fit portion 208. Details of this portion will be described later.

[0042] The header housing 100 is a holding member made of an insulating material and has a generally rectangular parallelepiped shape, and has an upper surface 102, a lower surface 104, widthwise side surfaces 106 and 108, and thicknesswise side surfaces 110 and 112. Mounting holes 114 for press-fit terminals 200A are formed so as to penetrate the upper surface 102 and the lower surface 104 of the header housing 100, and the press-fit terminals 200A are press-fitted and fixed into the mounting holes 114. The press-fit terminals 200A may be integrally formed with the header housing 100 by insert molding.

[0043] Legs 116 protruding downward are formed at each of the four corners in the width and thickness directions on the underside 104 of the header housing 100. When the press-fit terminal 200A is inserted into the printed wiring board 300, these legs 116 come into contact with the upper surface of the printed wiring board 300, stabilizing the header housing 100.

[0044] Press-fit terminal 200A has fixing portion 202 formed between contact pin 204 and press-fit portion 208. Fixing portion 202 is a member that is wider in the width direction than press-fit portion 208 and narrower than shoulder portion 206, and is a flat member that is long in the vertical direction, and is press-fitted and fixed into mounting hole 114 of header housing 100. Note that fixing portion 202 may be formed with a protrusion or the like to prevent it from coming off so that it can be press-fitted and fixed into mounting hole 114 of header housing 100, but a description thereof will be omitted.

[0045] 6, when fixing portion 202 is fixed in mounting hole 114, the upper surface of shoulder portion 206 and upper surface 102 of header housing 100 are aligned in the same plane, and contact pin 204 protrudes upward from shoulder portion 206 and upper surface 102 of header housing 100. This makes it possible to apply a pressing force to the upper surface of shoulder portion 206 with the underside of a press-fit tool or press-fit jig when inserting press-fit terminal 200A into a corresponding through-hole of a printed wiring board.

[0046] [Variation 2] In the above-described first modification, the press-fit terminal 200A has been described as having a shape extending substantially linearly, but the present disclosure is not limited to this shape, and the long press-fit terminal may have a shape that is bent substantially vertically halfway. A side-type right-angle connector 15 having a press-fit terminal 250 having a vertically bent shape will be described with reference to Figures 7(A) to 7(C).

[0047] The right-angle connector 15 includes a housing 150 and a plurality of press-fit terminals 250 fixed to the housing 150. In this modification, a total of 18 press-fit terminals 250 are fixed to the housing 150, six in the width direction and three rows in the vertical direction.

[0048] The housing 150 is a holding member made of an insulating material and has a generally rectangular parallelepiped shape, and has an upper surface 152, a lower surface 154, widthwise side surfaces 156 and 158, a front surface 160 which is a side surface in the thickness direction, and a rear surface 162. A mating opening 164 for mating with a mating connector (not shown) is formed in the front surface 160, and a plurality of mounting holes 168 for press-fit terminals 250 are formed at the innermost part of the mating opening 164, penetrating a bottom surface 166 extending parallel to the front surface 160 and the rear surface 162. The press-fit terminals 250 are press-fitted and fixed into these mounting holes 168. The press-fit terminals 250 may be integrally formed with the housing 150 by insert molding.

[0049] As shown in FIGS. 7(A) and 7(C), the press-fit terminal 250 includes a fixed portion 252, a contact pin 254, a bent portion 256, a shoulder portion 258, and a press-fit portion 260.

[0050] The fixing portion 252 is a straight, elongated member that is press-fitted and fixed into the mounting hole 168 of the housing 150. The contact pin 254 extends straight from the fixing portion 252 and extends from the bottom surface 166 of the fitting opening 164 of the housing 150 into the fitting opening 164.

[0051] Bent portion 256 extends from rear surface 162 and then bends downward at approximately 90 degrees as shown in Fig. 7(A). Shoulder portion 258 is formed below bent portion 256 and protrudes symmetrically in the width direction with respect to the axis of press-fit terminal 250.

[0052] The shoulder portion 258 is formed between the bent portion 265 and the press-fit portion 260, and is formed above the lower surface 154 of the housing 150. When the press-fit portion 260 is inserted into the through-hole 310 of the printed wiring board 300, the shoulder portion 258 receives the pressing force of the press-fit tool.

[0053] The press-fit portion 260 has the same shape as the press-fit portion 208 of the press-fit terminal 200 of the above embodiment, and therefore a detailed description thereof will be omitted.

[0054] The header connector 10 and right angle connector 15 described above can be mounted in the through holes 310, 310A of the printed wiring boards 300, 300A with a more stable holding force than press-fit terminals having a so-called elliptical or egg-shaped outer shape.

[0055] In the above embodiment and modified examples, the contact pins 204, 254 of the press-fit terminals 200, 200A, 250 are configured as long, linear members, but they may also have the shape of a female contact. [Explanation of symbols]

[0056] 10 Header Connector 15 Right Angle Connector 100 Header Housing 102 Top surface 104 Bottom surface 106, 108 Width side 110, 112 Thickness direction side 114 Mounting hole 116 Legs 150 Housing 152 Top surface 154 Bottom surface 156, 158 Width side 160 Front 162 Rear 164 mating opening 166 bottom 168 Mounting hole 200, 200A press-fit terminals 202 Fixed part 204 Contact pin 206 Shoulder 208 Press-fit part 210 Lower fixed end 212 Upper fixed end 214 Slit 216, 218 Elastically deformable legs 220, 222 middle part 224, 226 Lower bulge 228, 230 Upper bulge 232 Bottom end 234 Top 250 Press-fit terminal 252 Fixed part 254 contact pins 256 Bend 258 Shoulder 260 Press-fit part 300, 300A printed wiring board 310, 310A through hole 312, 312A lower end part 314, 314A upper end part

Claims

1. a press-fitting portion including a pair of elastically deformable legs having a double-supported beam structure that, when inserted into a through-hole of a printed wiring board, is electrically connected to a conductive material on an inner peripheral surface of the through-hole, and is formed so as to be connected to each other at fixed ends on the front and rear sides in the insertion direction into the through-hole, thereby forming a slit; A press-fit terminal in which the pair of elastically deformable legs each have two bulging portions that bulge out in the width direction more than the middle portion on the front and rear sides in the insertion direction into the through hole, and the width from the middle portion to the two bulging portions changes continuously, resulting in a tapered shape.

2. 2. The press-fit terminal according to claim 1, wherein the length of the slit in the insertion direction is longer on the front side and the rear side than the two bulging portions.

3. The press-fit terminal of claim 2, wherein the shape of the slit is an elliptical shape with a narrowed center, with the front and rear sides in the insertion direction being wider in the width direction than the middle part, corresponding to the shape of the pair of elastically deformable legs.

4. The press-fit terminal according to claim 1 , wherein the length of the slit in the insertion direction is longer than the length of the through-hole.

5. The press-fit terminal of claim 4, wherein the shape of the slit is an elliptical shape with a narrowed center, with the front and rear sides in the insertion direction being wider in the width direction than the middle part, corresponding to the shape of the pair of elastically deformable legs.

6. A connector assembly comprising the press-fit terminal according to any one of claims 1 to 5 and an insulating holding member, wherein the press-fit terminal further has a fixing portion, and the fixing portion is fixed to the holding member.

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