Press-fit terminal and connection structure of press-fit terminal

Abstract

A press-fit terminal (10) is provided with a tip section (11), an elastic section (12), and a main body section (13). The elastic section (12) has a pair of beam sections (21). Each beam section (21) has a front beam section (22), a rear beam section (24), and a press-fit section (23). The front inclined section (25) of the front beam section (22) has a contact start point (33) in front of the front end (A) of the hole (19), and the contact start point (33) comes into contact with the opening end section (93) of the through hole (91) first when pressed into the through hole (91). The peripheral edge of the eyelet (19) has: a front-side hole end section (28) that expands from the front end (A) of the eyelet (19) toward the outside in the width direction in the rear direction; and a rear-side hole end section (29) that expands from the rear end (B) of the eyelet (19) toward the outside in the front-direction width direction. The R of the rear-side hole end portion (29) is smaller than the R of the front-side hole end portion (28).

Description

Technical Field

[0001] The present invention relates to a press-fit terminal and a connection structure of the press-fit terminal. Background Art

[0002] The press-fit terminal disclosed in Patent Document 1 has an elastic portion (press-fit portion) that is press-fitted into a through hole of a substrate in the axial direction. The elastic portion has a perforation, and when being press-fitted into the through hole, it elastically deforms in a direction to narrow the opening width of the perforation and contacts the inner peripheral surface of the through hole. Such press-fit terminals are also disclosed in Patent Documents 2 to 4. Prior Art Documents Patent Documents

[0003] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2021-163641 Patent Document 2: Japanese Unexamined Patent Application Publication No. 2021-163525 Patent Document 3: Japanese Unexamined Patent Application Publication No. 2020-166954 Patent Document 4: Japanese Unexamined Patent Application Publication No. 2004-127610 Summary of the Invention Problems to be Solved by the Invention

[0004] When the press-fit terminal is press-fitted into the through hole and elastically deformed, cracks may occur on the surface of the press-fit terminal. In Patent Documents 1 to 4 described above, the shape, arrangement, etc. of the perforation are not sufficiently considered, and there is room for further improvement in order to suppress such damage to the press-fit terminal. In addition, there are problems in achieving both reduction of damage to the press-fit terminal and reduction of damage to the substrate.

[0005] Here, an object of the present invention is to suppress damage to the press-fit terminal and the substrate when being press-fitted into the through hole. Means for Solving the Problems

[0006] The press - fit terminal of the present invention is press - fit axially into a through - hole of a substrate. The press - fit terminal successively includes a tip portion, an elastic portion, and a main body portion from the front - end side in the axial direction. The elastic portion has a pair of beam portions. The pair of beam portions are opposed to each other in the width direction orthogonal to the axial direction with a hole therebetween, and apply an elastic reaction force to the inner peripheral surface of the through - hole. The pair of beam portions have: a front beam portion connected to the tip portion on the front - end side in the axial direction; a rear beam portion connected to the main body portion on the rear - end side in the axial direction; and a press - in portion located between the front beam portion and the rear beam portion in the axial direction. The front beam portion has a front - side inclined portion at the side end on the outer side in the width direction. The front - side inclined portion inclines outward in the width direction from the tip - portion side toward the press - in portion. The rear beam portion has a rear - side inclined portion at the side end on the outer side in the width direction. The rear - side inclined portion inclines outward in the width direction from the main - body - portion side toward the press - in portion. The front - side inclined portion has a contact start portion in front of the front - end in the axial direction of the hole. The contact start portion first contacts the opening end portion of the through - hole when being pressed into the through - hole. The periphery of the hole has: a front - side hole end portion that expands outward in the width direction from the front - end in the axial direction of the hole toward the rear; and a rear - side hole end portion that expands outward in the width direction from the rear - end in the axial direction of the hole toward the front. The radius R of the rear - side hole end portion is smaller than the radius R of the front - side hole end portion. Advantages of the Invention

[0007] According to the present invention, damage to the press - fit terminal and the substrate during press - fitting into the through - hole can be suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a perspective view of the press - fit terminal according to Embodiment 1 of the present invention. Figure 2 It is a top view of the tip portion and the elastic portion of the press - fit terminal. Figure 3 It is a front view of the press - fit terminal. Figure 4 It is a view showing a state where the substrate is cut to show the contact start portion of the press - fit terminal in contact with the opening end portion of the through - hole. Figure 5 It is a view showing a state where the substrate is cut to show the press - fit terminal inserted into the through - hole. DETAILED DESCRIPTION OF THE INVENTION

[0009] [Description of Embodiments of the Present Invention] First, embodiments of the present invention will be listed and described. (1) The press-fit terminal of the present invention is press-fitted axially into a through-hole of a substrate. The press-fit terminal sequentially includes a tip portion, an elastic portion, and a main body portion from the front end side in the axial direction. The elastic portion has a pair of beam portions. The pair of beam portions are opposed to each other in the width direction orthogonal to the axial direction with a hole therebetween, and an elastic reaction force acts on the inner peripheral surface of the through-hole. The pair of beam portions have a front beam portion connected to the tip portion at the front end side in the axial direction, a rear beam portion connected to the main body portion at the rear end side in the axial direction, and a press-in portion located between the front beam portion and the rear beam portion in the axial direction. The front beam portion has a front-side inclined portion at the side end on the outer side in the width direction. The front-side inclined portion inclines outward in the width direction from the tip portion side toward the press-in portion. The rear beam portion has a rear-side inclined portion at the side end on the outer side in the width direction. The rear-side inclined portion inclines outward in the width direction from the main body portion side toward the press-in portion. The front-side inclined portion has a contact start portion in front of the front end in the axial direction of the hole. The contact start portion first contacts the opening end portion of the through-hole when being press-fitted into the through-hole. The periphery of the hole has a front-side hole end portion that expands outward in the width direction from the front end in the axial direction of the hole toward the rear, and a rear-side hole end portion that expands outward in the width direction from the rear end in the axial direction of the hole toward the front. The R of the rear-side hole end portion is smaller than the R of the front-side hole end portion.

[0010] When the press-fit terminal is press-fitted into the through-hole, the contact start portion of the front-side inclined portion first contacts the opening end portion of the through-hole, and the front-side inclined portion elastically deforms. Here, since the contact start portion is located in front of the front end in the axial direction of the hole, compressive stress acts on the front-side inclined portion. Through deformation analysis, it is known that the cracks in the conventional front beam portion originate from the tensile stress generated in the front-side inclined portion and the like when being press-fitted into the through-hole. Therefore, the compressive stress acting on the front-side inclined portion can suppress the generation of cracks and prevent problems before they occur. When the press-fit terminal is further press-fitted into the through-hole, the rear-side inclined portion elastically deforms greatly, and the opening width near the rear-side hole end portion of the hole decreases. Here, since the R of the rear-side hole end portion is smaller than the R of the front-side hole end portion, the rear-side inclined portion can elastically deform smoothly in the direction of reducing the opening width. Therefore, damage to the substrate generated when the rear-side inclined portion is press-fitted into the through-hole can be suppressed. Thus, according to the present invention, damage to the press-fit terminal and damage to the substrate can both be reduced.

[0011] (2) Preferably, it is a plate-shaped press-fit terminal with a plate thickness of 0.2 mm or more and 0.6 mm or less, and the plate surface is arranged along the width direction. When the axial distance from the front end in the axial direction of the hole to the contact start portion is set as P, the relational expression of 0.05 mm ≤ P ≤ 0.11 mm holds.

[0012] When the axial distance P from the front end of the hole to the contact start portion satisfies the above relationship, damage to the press-fit terminal can be effectively suppressed. In addition, when the distance P is less than 0.05 mm, tensile stress may be generated in the front inclined portion. On the other hand, when the distance P is greater than 0.11 mm, damage to the substrate generated when the front inclined portion is pressed into the through hole may increase.

[0013] (3) Preferably, the front hole end is bent along the arc of a perfect circle.

[0014] When the press-fit terminal is pressed into the through hole, crushing of the front hole end can be suppressed, so that the compressive stress can act on the front inclined portion for a longer time.

[0015] (4) Preferably, in the connection structure of the press-fit terminal according to any one of (1) to (3), the press-in portion contacts the inner peripheral surface of the through hole along the axial direction, and the entire hole is received inside the through hole.

[0016] Since both the portion of the press-in portion close to the front inclined portion and the portion close to the rear inclined portion can contact the inner peripheral surface of the through hole, the holding force of the press-fit terminal with respect to the substrate can be improved.

[0017] [Details of the Embodiment of the Present Invention] The following describes specific examples of the present invention with reference to the drawings. In addition, the present invention is not limited to this example, but is shown by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0018] <Embodiment 1> The press-fit terminal 10 according to Embodiment 1 of the present invention has a shape extending in the axial direction and is pressed into the through hole 91 of the substrate 90. In addition, in the following description, regarding the front-rear direction, the top side where the press-fit terminal 10 is first pressed into the through hole 91 is referred to as the front end side in the axial direction, or simply as the front end side. That is, the axial direction is the front-rear direction, and the lower side of each figure is the front side. The left-right direction of each figure is the width direction. Both sides in the width direction are sometimes referred to as the outer sides in the width direction. The outer side in the width direction is sometimes simply referred to as the outer side, and the inner side in the width direction is sometimes simply referred to as the inner side. In each figure, the front side is denoted by the reference sign F, and the width direction (left side in the drawing) is denoted by the reference sign W. In addition, the structure of the elastic portion 12 described later is described based on the form before deformation, that is, before the press-fit terminal 10 is pressed into the through hole 91, unless otherwise specified.

[0019] (Structure of the Press-Fit Terminal) The press-fit terminal 10 is made of conductive metal and is formed into an axially elongated shape by punching a metal plate or the like. The plate surface of the press-fit terminal 10 is arranged along the width direction. The plate thickness of the press-fit terminal 10 is orthogonal to the plate surface and is arranged toward the width direction.

[0020] As Figure 1 shown, the press-fit terminal 10 sequentially includes a tip portion 11, an elastic portion 12, and a main body portion 13 from the front end side in the axial direction. The main body portion 13 is formed over more than half of the entire length of the press-fit terminal 10 and is mounted on a connector housing (not shown). Figure 1 The main body portion 13 shown is formed in a straight line along the axial direction, but it can also be bent midway in the axial direction. The main body portion 13 has a tab portion 14 that contacts a mating terminal part (not shown) at the rear end, and a holding portion 15 that is press-fitted into the connector housing in front of the tab portion 14. Also, the main body portion 13 has a pair of protruding pieces 16 that protrude toward both sides in the width direction at a position close to the elastic portion 12. The rear ends of the respective protruding pieces 16 are arranged along the width direction. A jig (not shown) is pushed from the rear against the rear ends of the respective protruding pieces 16. The press-fit terminal 10 is pressed by the jig and press-fitted into the through-hole 91 of the substrate 90.

[0021] As Figure 2 and Figure 3 shown, the tip portion 11 has a reduced-diameter portion 17 that tapers toward the front end side. The reduced-diameter portion 17 functions to guide the press-fit terminal 10 into the through-hole 91. The tip portion 11 has curved chamfered portions 18 at the corner portions of the side ends on both sides in the width direction. The chamfered portions 18 are formed from the tip portion 11 to the elastic portion 12. In addition, the tip portion 11, except for the reduced-diameter portion 17, is formed in a shape that extends along the axial direction with a certain width dimension.

[0022] As Figure 2 shown, the elastic portion 12 has a hole 19 that penetrates in the plate thickness direction at the central portion in the width direction, and a pair of beam portions 21 at the end portions on both sides in the width direction. Each beam portion 21 is formed in a shape that bulges outward through the hole 19. The inner side ends of the respective beam portions 21 define the periphery of the hole 19 described later. The outer side ends of the respective beam portions 21 contact the inner peripheral surface of the through-hole 91 when being press-fitted into the through-hole 91 and are electrically connected to the conductive portion 92 formed on the inner peripheral surface of the through-hole 91 (see Figure 4 and Figure 5 ).

[0023] As Figure 2 shown, each beam portion 21 sequentially includes a front beam portion 22, a press-in portion 23, and a rear beam portion 24 from the front end side in the axial direction. The front beam portion 22 has a front-side inclined portion 25 that expands outward from the top end portion 11 to the press-fitting portion 23 at the outer side end. The front end of the front-side inclined portion 25, i.e., the connecting end with the top end portion 11, is located in front of the front end A of the hole 19. The rear end of the front-side inclined portion 25, i.e., the connecting end with the press-fitting portion 23, is located behind the front end A of the hole 19 and in front of the front-back center of the hole 19.

[0024] The rear beam portion 24 has a rear-side inclined portion 26 that expands outward from the main body portion 13 to the press-fitting portion 23 at the outer side end. The inclination angle of the rear-side inclined portion 26 with respect to the axial direction is greater than the inclination angle of the front-side inclined portion 25 with respect to the axial direction. The axial length of the rear-side inclined portion 26 is shorter than the axial length of the front-side inclined portion 25. The rear end of the rear-side inclined portion 26, i.e., the connecting end with the main body portion 13, is located behind the rear end B of the hole 19. The front end of the rear-side inclined portion 26, i.e., the connecting end with the press-fitting portion 23, is located in front of the rear end B of the hole 19 and behind the front-back center of the hole 19.

[0025] The press-fitting portion 23 has an intermediate side end portion 27 that extends slightly inclined inward in the axial direction from the rear-side inclined portion 26 to the front-side inclined portion 25 at the outer side end. The intermediate side end portion 27 is axially disposed within the range of the hole 19.

[0026] As Figure 2 shown, the hole 19 is a shape that extends axially relatively long as a whole and is symmetric about the axis S passing through the center in the width direction. The periphery of the hole 19 has: a front-side hole end portion 28 including the front end A of the hole 19; a rear-side hole end portion 29 including the rear end B of the hole 19; and a pair of intermediate hole edge portions 31 in the width direction located between the front-side hole end portion 28 and the rear-side hole end portion 29.

[0027] The front-side hole end portion 28 expands in a manner of bending from the front end A of the hole 19 to both sides in the width direction and then extending rearward, and is arc-shaped as a whole. Specifically, the front-side hole end portion 28 bends along the arc of a perfect circle as a whole, connecting the two ends in the width direction to the intermediate hole edge portions 31. The front-side inclined portion 25 is located on both sides in the width direction of the front-side hole end portion 28.

[0028] The rear-side hole end portion 29 expands forward while bending from the rear end B of the hole 19 to both sides in the width direction, and is arc-shaped as a whole. Specifically, the rear-side hole end portion 29 is shorter than the front-side hole end portion 28 in both the circumferential direction and the axial direction as a whole, and bends along the arc of a perfect circle. The R of the rear-side hole end portion 29 is smaller than the R of the front-side hole end portion 28. In addition, in this specification, R corresponds to the radius of curvature.

[0029] In addition, the periphery of the hole 19 has a pair of tapered portions 32 that are tapered and narrowed in the circumferential direction from each intermediate hole edge portion 31 to the rear hole end portion 29. The front inclined portion 25 is located on both sides in the width direction of the front hole end portion 28 and each tapered portion 32. The rear beam portion 24 is defined by the rear hole end portion 29, each tapered portion 32, and the rear inclined portion 26, and has a shape that extends with little change in width dimension.

[0030] Each intermediate hole edge portion 31 extends axially for a long distance and is arranged in parallel with each other. The rear half portion and the intermediate side end portion 27 of the front inclined portion 25 are located outside the width direction of each intermediate hole edge portion 31.

[0031] (Function and connection structure of press-fit terminal) The press-fit terminal 10 is inserted into the through hole 91 of the substrate 90 from the tip portion 11 side by pressing each protruding piece 16 with a jig (not shown). The front inclined portion 25 is inserted into the through hole 91 after the tip portion 11. As Figure 4 shown, when starting to insert into the through hole 91, the contact start portion 33 of the front inclined portion 25 first contacts the opening end portion 93 of the through hole 91 on the surface of the substrate 90. The contact start portion 33 of the front inclined portion 25 is the portion that first contacts the opening end portion 93 of the through hole 91 and is located in front of the front end A of the hole 19.

[0032] After the contact start portion 33 of the front inclined portion 25 contacts the opening end portion 93 of the through hole 91, by further inserting the press-fit terminal 10, the front beam portion 22 slides on the opening end portion 93 of the through hole 91, and the front beam portion 22 and the press-in portion 23 elastically deform inward together. As described above, since the contact start portion 33 is located in front of the front end A of the hole 19, compressive stress acts on the front inclined portion 25 including the contact start portion 33, and generation of cracks in the front inclined portion 25 can be suppressed.

[0033] In addition, in the case of the first embodiment, the plate thickness of the press-fit terminal 10 is set to 0.2 mm to 0.6 mm, preferably 0.3 mm to 0.5 mm, and more preferably 0.4 mm. In this case, when the axial distance from the front end A of the hole 19 to the contact start portion 33 is set to P (refer to Figure 4) When it is, the value of P is in the range of 0.05 mm ≤ P ≤ 0.11 mm. When the press - fit terminal 10 with a plate thickness of 0.2 mm to 0.6 mm satisfies the relation of 0.05 mm ≤ P ≤ 0.11 mm, it can be confirmed that it is effective in suppressing the generation of cracks in the press - fit terminal 10. That is, when the distance P is less than 0.05, tensile stress acts on the front - side inclined portion 25, and it is difficult to suppress the generation of cracks. On the other hand, when the distance P is greater than 0.11, the damage to the substrate 90 generated when the front - side inclined portion 25 is pressed into the through - hole 91 may increase. Therefore, the value of P is in the range of 0.05 mm ≤ P ≤ 0.11 mm.

[0034] When the insertion of the press - fit terminal 10 into the through - hole 91 is further carried out, the intermediate - side end portion 27 contacts the inner peripheral surface of the through - hole 91, and the press - in portion 23 elastically deforms greatly inward. When the tapered portions 32 of the eyelet 19 deform in a way that they approach each other, accordingly, the rear - beam portion 24 also elastically deforms inward (refer to Figure 5 ). As described above, since the R of the rear - side hole end portion 29 is smaller than the R of the front - side hole end portion 28, the rear - side inclined portion 26 can elastically deform smoothly in the direction of narrowing the opening width of the eyelet 19 near the rear - side hole end portion 29, and the damage to the substrate 90 generated when the rear - side inclined portion 26 is pressed into the through - hole 91 can be suppressed.

[0035] In the case of the first embodiment, the insertion force in the final insertion state where the portion of the press - in portion 23 near the rear - beam portion 24 or the rear - beam portion 24 contacts the opening end portion 93 of the through - hole 91 is smaller than the insertion force in the initial insertion state where the contact start portion 33 of the front - beam portion 22 contacts the opening end portion 93 of the through - hole 91. Thus, due to the smaller insertion force in the final insertion state of the press - fit terminal 10, when the press - fit terminal 10 is inserted into the through - hole 91 with an axial offset, the damage to the substrate 90 can be reduced.

[0036] When the press - fit terminal 10 is inserted into the through - hole 91 to an appropriate depth, as Figure 5 shown, the whole of the eyelet 19 is arranged in a way that it is accommodated inside the through - hole 91. The press - in portion 23 of the beam portion 21 contacts the inner peripheral surface of the through - hole 91 along the axial direction and applies an elastic reaction force to the inner peripheral surface of the through - hole 91. Thereby, the press - fit terminal 10 is stably held on the substrate 90 and is electrically connected to the conductive portion 92.

[0037] As described above, according to the first embodiment, since the contact start portion 33 of the front inclined portion 25 is located in front of the front end A of the hole 19, when the press-fit terminal 10 is pressed into the through hole 91, compressive stress can act on the front inclined portion 25. Therefore, the generation of cracks in the front inclined portion 25 can be prevented. In addition, since the R of the rear hole end portion 29 is smaller than the R of the front hole end portion 28, the rear beam portion 24 can elastically deform inward smoothly. Therefore, damage to the substrate 90 generated when the rear inclined portion 26 is pressed into the through hole 91 can be suppressed. As a result, in the first embodiment, damage to the press-fit terminal 10 and the substrate 90 during pressing into the through hole 91 can be suppressed.

[0038] In addition, since the front hole end portion 28 is curved along the arc of a perfect circle, when the press-fit terminal 10 is pressed into the through hole 91, crushing of the front hole end portion 28 can be suppressed, and compressive stress can act on the front inclined portion 25 for a longer time.

[0039] [Other Embodiments of the Present Invention] It should be considered that the embodiments disclosed this time are illustrative in all aspects and not restrictive. In the case of the above-described first embodiment, the press-fit terminal has a shape that is symmetric about an axis passing through the center in the width direction. In contrast, according to other embodiments, the press-fit terminal may also have a shape that is asymmetric about an axis passing through the center in the width direction. For example, the elastic portion may also have an asymmetric shape. Explanation of Reference Numerals

[0040] 10: Press-fit terminal 11: Tip portion 12: Elastic portion 13: Body portion 14: Tab portion 15: Holding portion 16: Extended piece 17: Reduced diameter portion 18: Chamfered portion 19: Hole 21: Beam portion 22: Front beam portion 23: Press-in portion 24: Rear beam portion 25: Front inclined portion 26: Rear inclined portion 27: Intermediate side end portion 28: Front hole end portion 29: Rear hole end portion 31: Intermediate hole edge portion 32: Tapered portion 33: Contact start portion 90: Substrate 91: Through-hole 92: Conductive part 93: Opening end A: Front end of the hole B: Rear end of the hole P: Distance S: Axis

Claims

1. A press-fit terminal is press-fitted axially into a through-hole of a substrate. The press-fit terminal sequentially includes a tip portion, an elastic portion, and a main body portion from the front end side in the axial direction. The elastic portion has a pair of beam portions which are opposed to each other in the width direction orthogonal to the axial direction with a hole therebetween, and an elastic reaction force acts on the inner peripheral surface of the through-hole. The pair of beam portions has: a front beam portion connected to the tip portion at the front end side in the axial direction; a rear beam portion connected to the main body portion at the rear end side in the axial direction; and a press-in portion located between the front beam portion and the rear beam portion in the axial direction. The front beam portion has a front-side inclined portion at the side end on the outer side in the width direction, and the front-side inclined portion inclines outward in the width direction from the tip portion side toward the press-in portion. The rear beam portion has a rear-side inclined portion at the side end on the outer side in the width direction, and the rear-side inclined portion inclines outward in the width direction from the main body portion side toward the press-in portion. The front-side inclined portion has a contact start portion in front of the front end in the axial direction of the hole, and the contact start portion first contacts the opening end of the through-hole when being press-fitted into the through-hole. The periphery of the hole has: a front-side hole end portion that expands outward in the width direction from the front end in the axial direction of the hole toward the rear; and a rear-side hole end portion that expands outward in the width direction from the rear end in the axial direction of the hole toward the front. The R of the rear-side hole end portion is smaller than the R of the front-side hole end portion.

2. The press-fit terminal according to claim 1, wherein, The press-fit terminal is a plate-shaped press-fit terminal having a plate thickness of 0.2 mm or more and 0.6 mm or less, and the plate surface is arranged along the width direction. When the axial distance from the front end in the axial direction of the hole to the contact start portion is set as P, the relational expression 0.05 mm ≤ P ≤ 0.11 mm holds.

3. The press-fit terminal according to claim 1, wherein, The front-side hole end portion is curved along an arc of a perfect circle.

4. A connection structure of a press-fit terminal, wherein the press-fit terminal is the press-fit terminal according to any one of claims 1 to 3, The press-in portion contacts the inner peripheral surface of the through-hole along the axial direction, and the whole hole is accommodated inside the through-hole.

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