Press-fit terminals and connectors

Abstract

The aim is to improve the balance between reducing insertion force and increasing holding force. The crimp terminal includes a crimping portion comprising two contact tabs facing each other across an orifice. Each of the two contact tabs includes: a parallel portion extending from the parallel portion toward the direction of insertion into the crimping portion, and a rear spring portion extending from the parallel portion in the opposite direction to the direction of insertion into the crimping portion. The thickness of the crimping portion is 0.3 mm to 0.5 mm. When the length of the orifice is set to Le [mm] and the length of the parallel portion is set to Ls [mm], Ls / Le is 0.57 to 0.65. When the front spring strength is set to G1 [mm]... 3 And set the rear spring strength to G2 [mm] 3 When G1 / G2 is above 0.55 and below 1.45.

Description

Technical Field

[0001] This disclosure relates to a press-fit terminal and connector device. Background Technology

[0002] Patent Document 1 discloses a press-fit terminal having a connection portion consisting of a slit with a width extending through the front and back sides and two beam members facing each other and sandwiching the slit. In Patent Document 1, the beam members are configured such that the thickness of the front end side and the rear end side of the connection portion is thinner than the thickness of the center of the connection portion, and the length of the slit portion is configured such that the length from the center of the connection portion to the rear end side is shorter than the length from the center of the connection portion to the front end side.

[0003] Patent Document 2 discloses a press-fit terminal having: an insertion portion inserted into a through hole, a pressure holding portion connected to the insertion portion and press-fitted into and held within the through hole, and a main body portion connected to the pressure holding portion, wherein an opening is formed extending longitudinally from the center of the pressure holding portion toward the main body portion and the insertion portion. In Patent Document 2, the ratio of the length in the longitudinal direction from the center of the pressure holding portion to one end of the opening on the main body portion side to the length in the longitudinal direction from the center of the pressure holding portion to the other end of the opening on the insertion portion side is specified to be in the range of 80:220 to 120:180.

[0004] Existing technical documents

[0005] Patent Document 1: International Publication No. 2008 / 038331

[0006] Patent Document 2: Japanese Patent Application Publication No. 2008-165987 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Crimp terminals are evaluated, for example, by insertion force and retention force. Insertion force is the load required to insert the crimp terminal into a through-hole. Retention force is the load required to pull the crimp terminal out of the through-hole. As crimp terminals, it is desirable for them to be easy to insert into the through-hole and not easily dislodged. Therefore, for crimp terminals, it is required to reduce the insertion force and increase the retention force.

[0009] In addition, in recent years, there has been a demand for miniaturization of connectors with press-fit terminals, miniaturization of the substrates into which the press-fit terminals are pressed, and high density of press-fit terminals. As a result, there is a demand for smaller diameter through holes, and further a demand for thinner press-fit terminals.

[0010] Regarding the press-fit terminals made in this way, there is room for further improvement in balancing reducing insertion force and increasing retention force.

[0011] Therefore, the purpose of this disclosure is to improve the balance between reducing insertion force and increasing retention force.

[0012] Technical solutions for solving the problem

[0013] The press-fit terminal disclosed herein is press-fitted into a through-hole formed in a substrate. The press-fit terminal includes a press-fit portion comprising two contact tabs facing each other across an aperture. Each of the two contact tabs includes: a parallel portion that is parallel to each other; a front spring portion extending from the parallel portion in a direction to which the press-fit portion is inserted; and a rear spring portion extending from the parallel portion in a direction opposite to the direction to which the press-fit portion is inserted. The thickness of the press-fit portion is 0.3 mm to 0.5 mm. Regarding the press-fit portion, when the length of the aperture is set to Le [mm] and the length of the parallel portion is set to Ls [mm], Ls / Le is 0.57 to 0.65. Regarding the press-fit portion, when the front spring strength calculated under the following conditions is set to G1 [mm]... 3 And set the rear spring strength to G2 [mm] 3 When G1 / G2 is above 0.55 and below 1.45,

[0014] [condition]

[0015] • Set the direction of insertion of the above-mentioned crimping terminal to forward, and set the direction opposite to the insertion direction to backward;

[0016] • The position 0.1mm backward from the front end of the above-mentioned hole is set as the front reference, and the position 0.1mm forward from the rear end of the above-mentioned hole is set as the rear reference.

[0017] • Assuming a front reference plane perpendicular to the inner edge of the front spring portion and the outer edge of the front spring portion at the aforementioned front reference point, the moment of inertia of the section of the front spring portion at this front reference plane is set as I1 [mm]. 4 ];

[0018] • Assuming a rear reference plane perpendicular to the inner edge and outer edge of the rear spring portion at the aforementioned rear reference point, the moment of inertia of the section of the rear spring portion at this rear reference plane is set as I² [mm]. 4 ];

[0019] • The length of the press-fit part in the insertion direction from the end of the front spring part on the straight outer edge of the parallel part to the front end of the hole is defined as L1 [mm];

[0020] • The length of the press-fit part in the insertion direction from the end of the rear spring portion on the straight outer edge of the parallel portion to the rear end of the eyelet is defined as L2 [mm];

[0021] • Set the front spring strength G1 to I1 / L1 [mm] 3 The rear spring strength G2 is set to I2 / L2 [mm]. 3 ].

[0022] Invention Effects

[0023] According to this disclosure, the balance between reducing insertion force and increasing retention force is improved. Attached Figure Description

[0024] Figure 1 This is a front view showing the press-fit terminals involved in the embodiment.

[0025] Figure 2 This is an explanatory diagram showing the state of the press-fit part being inserted into the through hole.

[0026] Figure 3 yes Figure 2 Sectional view along line III-III.

[0027] Figure 4 This is a cross-sectional view showing other press-fit terminals.

[0028] Figure 5 This is an explanatory diagram showing the cross-sectional shape of the front spring section at the front reference plane.

[0029] Figure 6 This is a schematic diagram showing the connector assembly.

[0030] Figure 7 This is a graph showing the evaluation results of the press-fit terminals. Detailed Implementation

[0031] [Description of embodiments of this disclosure]

[0032] First, embodiments of this disclosure will be described.

[0033] The press-fit terminals disclosed herein are as follows.

[0034] (1) A press-fit terminal, which is pressed into a through hole formed in a substrate.

[0035] The aforementioned press-fit terminal includes a press-fit portion comprising two contact tabs facing each other with holes spaced apart.

[0036] The two contact pieces mentioned above each include: parallel portions that are parallel to each other, a front spring portion extending from the parallel portions in the direction of insertion into the press-fit portion, and a rear spring portion extending from the parallel portions in the direction opposite to the direction of insertion into the press-fit portion.

[0037] The thickness of the aforementioned press-fit section is 0.3 mm to 0.5 mm.

[0038] Regarding the aforementioned press-fit section, when the length of the aforementioned orifice is set to Le [mm] and the length of the aforementioned parallel section is set to Ls [mm], Ls / Le is 0.57 or more and 0.65 or less.

[0039] Regarding the aforementioned press-fit section, the front spring strength calculated under the following conditions is set as G1 [mm]. 3 And set the rear spring strength to G2 [mm] 3 When G1 / G2 is above 0.55 and below 1.45,

[0040] [condition]

[0041] • Set the direction of insertion of the above-mentioned crimping terminal to forward, and set the direction opposite to the insertion direction to backward;

[0042] • The position 0.1mm backward from the front end of the above-mentioned hole is set as the front reference, and the position 0.1mm forward from the rear end of the above-mentioned hole is set as the rear reference.

[0043] • Assuming a front reference plane perpendicular to the inner edge of the front spring portion and the outer edge of the front spring portion at the aforementioned front reference point, the moment of inertia of the section of the front spring portion at this front reference plane is set as I1 [mm]. 4 ];

[0044] • Assuming a rear reference plane perpendicular to the inner edge and outer edge of the rear spring portion at the aforementioned rear reference point, the moment of inertia of the section of the rear spring portion at this rear reference plane is set as I² [mm]. 4 ];

[0045] • The length of the press-fit part in the insertion direction from the end of the front spring part on the straight outer edge of the parallel part to the front end of the hole is defined as L1 [mm];

[0046] • The length of the press-fit part in the insertion direction from the end of the rear spring portion on the straight outer edge of the parallel portion to the rear end of the eyelet is defined as L2 [mm];

[0047] • Set the front spring strength G1 to I1 / L1 [mm] 3 The rear spring strength G2 is set to I2 / L2 [mm]. 3 ].

[0048] Since Ls / Le is between 0.57 and 0.65, and G1 / G2 is between 0.55 and 1.45, it is possible to improve the balance between reducing insertion force and increasing holding force.

[0049] (2) Based on the press-fit terminal in (1), it is also possible that the spring strength G [mm] is... 3When G is set to G1+G2, G is 0.03mm. 3 Above 0.04mm 3 The following further improves the balance between reducing insertion force and increasing retention force.

[0050] (3) According to the press-fit terminal of (1) or (2), the outer edge of the front spring portion may be inclined toward the inside of the width direction of the press-fit portion as it moves forward, and the outer edge of the rear spring portion may be inclined toward the inside of the width direction of the press-fit portion as it moves backward. The front spring portion and the rear spring portion are prone to deformation.

[0051] (4) According to any of the methods in (1) to (3), the press-fit terminal may also have the outward-facing portion of the parallel part forming an arc shape when viewed along the insertion direction. The contact area with the inner circumferential surface of the through hole becomes larger.

[0052] (5) It can also be made into a connector device, comprising a connector including a press-fit terminal (4) and a substrate having a through hole, wherein the press-fit portion of the press-fit terminal is pressed into the through hole, and when viewed along the insertion direction, the radius of curvature of the outward portion of the parallel portion is the same as or smaller than the inner circumferential radius of the through hole. The contact area between the press-fit portion and the inner circumferential surface of the through hole increases.

[0053] [Details of the embodiments disclosed herein]

[0054] Hereinafter, specific examples of the press-fit terminals and connector devices of this disclosure are described with reference to the accompanying drawings. Furthermore, this disclosure is not limited to these examples, but is defined by the claims and is intended to include all modifications within the meaning and scope equivalent to the claims.

[0055] Furthermore, the press-fit terminal disclosed herein is significant in the following context: In press-fit terminals, all characteristics regarding holding force, contact area, and insertion force must be met at a high level. Here, holding force and insertion force are as already described. Contact area is the contact area between the press-fit terminal and the through-hole when the press-fit terminal is inserted into the through-hole of the substrate. For good electrical connection, a contact area as large as possible is desirable. When the press-fit terminal is inserted into the through-hole, it acts as a spring, pressing both sides of the press-fit terminal against the through-hole. The stiffer the spring of the press-fit terminal, the greater the holding force and contact area, but the greater the insertion force. Conversely, the softer the spring of the press-fit terminal, the smaller the insertion force, but the smaller the holding force and contact area. Thus, the holding force, contact area, and insertion force are influenced by the stiffness of the spring, resulting in a trade-off between the requirements for holding force and contact area and the requirements for insertion force.

[0056] Regarding all characteristics of retaining force, contact area, and insertion force, a shape is proposed to meet these requirements at a high level. Previously, the thickness of press-fit terminals was approximately 0.64 mm. However, considering the requirements for miniaturization and multi-polarization of press-fit terminals, a reduction in thickness is needed.

[0057] When studying the shape of a thin press-fit terminal (e.g., 0.4 mm thick), for example, instead of starting from scratch, we consider making a similar shape by scaling down an existing one. However, the thin press-fit terminal is not only thin but also small in size in the front view. Furthermore, when manufacturing press-fit terminals from sheet metal using processes such as stamping, there are dimensional limitations in the manufacturing process. Therefore, it may be difficult to process the press-fit terminal into a similar shape by scaling down an existing one. Therefore, the shape of the thin press-fit terminal needs to be re-examined.

[0058] Against the background described above, in this disclosure, research was conducted on the shape of a thin press-fit terminal that can satisfy the holding force, contact area and insertion force at a high level, and as a result, the shape of the press-fit terminal shown below was conceived.

[0059] [Implementation Method]

[0060] The following describes the press-fit terminals involved in the implementation method. Figure 1 This is a front view showing the press-fit terminal 20. Figure 2 This is an explanatory diagram showing the state in which the press-fit part 30 is inserted into the through hole 13. Figure 2 The image shows the press-fit terminal 20 before being inserted into the through hole 13 and the press-fit terminal 20 after being inserted into the through hole 13. Figure 3 yes Figure 2 Sectional view along line III-III.

[0061] The press-fit terminal 20 is a terminal that is pressed into a through-hole 13 formed in the substrate 12. Here, the substrate 12 is formed of an insulating board such as a glass epoxy board. A through-hole 13 is formed in the substrate 12, penetrating both the front and back sides. The through-hole 13 is circular. The through-hole 13 can also be square or the like. A conductive layer 13f based on a metal such as copper is formed on the inner surface of the through-hole 13. When the press-fit terminal 20 is pressed into the through-hole 13, the press-fit terminal 20 contacts the conductive layer 13f and is electrically connected to it. The conductive layer 13f can also be connected to circuitry formed on the surface of the substrate 12.

[0062] The press-fit terminal 20 is formed of metals such as copper or copper alloys. The press-fit terminal 20 can also be formed, for example, by stamping a metal sheet. A plating layer of tin, tin alloy, or the like can also be formed on the surface of the press-fit terminal 20.

[0063] The crimp terminal 20 includes a crimping portion 30. In this embodiment, a front portion 22 is connected to one end of the crimping portion 30, and a base portion 26 is connected to the other end of the crimping portion 30. The front portion 22 is the portion that first inserts into the through hole 13 when the crimp terminal 20 is inserted into the through hole 13. The base portion 26 is the portion connected to the electrical connection destination of the conductive layer 13f on the through hole 13 side. (To be described later...) Figure 6 In the example shown, the base end 26 is connected to the connector terminal portion 54. The direction of insertion of the crimping portion 30 is set to forward, and the direction opposite to the insertion direction is set to backward.

[0064] The press-fit portion 30 is the portion disposed between the front end portion 22 and the base end portion 26. The width W2 (the maximum width in this case) of the press-fit portion 30 is greater than the maximum width W1 of the front end portion 22, and also greater than the diameter φ of the through hole 13. Therefore, the press-fit portion 30 can contact the inner circumferential surface of the through hole 13. It can also be understood that the press-fit portion 30 is a portion used to achieve electrical contact with the conductive layer 13f by maintaining contact with the inner circumferential surface of the through hole 13.

[0065] More specifically, the press-fit terminal 20 is generally formed as a slender plate extending in a straight line.

[0066] The front end portion 22 includes a continuous rectangular plate-shaped portion of the same width. The two edges of this rectangular plate-shaped portion are parallel to each other. The width W1 of the front end portion 22 is less than the diameter φ of the through hole 13. At the front end of the rectangular plate-shaped portion of the front end portion 22 (the end opposite to the press-fit portion 30), a foremost end portion 22a is provided, which gradually narrows towards the front end. Due to the presence of the foremost end portion 22a, it is easy to insert the press-fit terminal 20 into the through hole 13. The front end portion 22 can be inserted into the through hole 13 with a gap relative to the inner circumferential surface of the through hole 13.

[0067] The base end portion 26 includes a continuous rectangular plate-like portion of the same width. The edges of the two sides of this rectangular plate-like portion are parallel to each other. The width of the base end portion 26 is less than the width W2 of the press-fit portion 30. Here, the width of the base end portion 26 is the same as the maximum width W1 of the front end portion 22. The width of the base end portion 26 may also be different from the width of the front end portion 22.

[0068] A crimping portion 30 is disposed between the front end portion 22 and the base end portion 26. The crimping portion 30 includes two contact pieces 34 facing each other, separated by an eyelet 31. The eyelet 31 is an elongated hole in the direction connecting the front end portion 22 and the base end portion 26. Examples of the shape of the eyelet 31 include a perfect circle, an ellipse, a cube, and a cuboid. The eyelet 31 is preferably elongated in the direction in which the crimping terminal is inserted. The contact pieces 34 are formed as elongated plates. One end of each of the two contact pieces 34 is connected to the front end portion 22. The other end of each of the two contact pieces 34 is connected to the base end portion 26.

[0069] The two contact pieces 34 each have a parallel portion 36, a front spring portion 35, and a rear spring portion 37.

[0070] The parallel portions 36 of the two contact pieces 34 are arranged side by side, each parallel to the other. More specifically, the outer edges 36a of the two parallel portions 36 are arranged in a straight line and are parallel to each other in the front-back direction. The inner edges of the two parallel portions 36 may also be arranged in a straight line and are parallel to each other in the front-back direction. However, depending on the shape of the aperture 31, part or all of the inner edges of the two parallel portions 36 may sometimes be curved.

[0071] The front spring portion 35 extends forward from the parallel portion 36 toward the insertion of the press-fit terminal 20. The front spring portion 35 is the portion that deforms more easily than the parallel portion 36 when the press-fit portion 30 is inserted into the through hole 13. The outer edge 35a of the front spring portion 35 slopes inward toward the width direction of the press-fit portion 30 as it moves forward. That is, the outer edge 35a of the front spring portion 35 connects to the outer edge 36a of the parallel portion 36 at its rear end, gradually slopes inward toward the width direction of the press-fit portion 30 as it moves forward, and connects to the outer edge of the front end portion 22 at its front end.

[0072] The outer edge 35a of the front spring portion 35 can be entirely straight, entirely curved, or a combination of straight and curved lines. The outer edge 35a of the front spring portion 35 and the outer edge 36a of the parallel portion 36 can be connected either curvedly or at an angle. Similarly, the outer edge 35a of the front spring portion 35 and the outer edge of the front end portion 22 can be connected either curvedly or at an angle. Here, the middle portion of the outer edge 35a of the front spring portion 35 is straight, while its two end portions are curved.

[0073] The rear spring portion 37 extends from the parallel portion 36 in the opposite direction (rearward) to the direction of insertion into the press-fit terminal 20. The rear spring portion 37 is the portion that deforms more easily than the parallel portion 36 when the press-fit portion 30 is inserted into the through hole 13. By positioning the front and rear of the parallel portion 36, the front spring portion 35 and the rear spring portion 37 are easily deformed, while the parallel portion 36 can be displaced inward without significant skew. The outer edge 37a of the rear spring portion 37 is inclined inward toward the width direction of the press-fit portion 30 as it moves rearward. That is, the outer edge 37a of the rear spring portion 37 is connected to the outer edge 36a of the parallel portion 36 at the front end, gradually moves inward toward the width direction of the press-fit portion 30 as it moves rearward, and is connected to the outer edge of the base end portion 26 at the rear end.

[0074] The outer edge 37a of the rear spring portion 37 can be entirely straight, entirely curved, or a combination of straight and curved lines. The outer edge 37a of the rear spring portion 37 can be connected to the outer edge 36a of the parallel portion 36 in either a curved or angular manner. Similarly, the outer edge 37a of the rear spring portion 37 can be connected to the outer edge of the base end portion 26 in either a curved or angular manner. Here, the middle portion of the outer edge 37a of the rear spring portion 37 is straight, while its two end portions are curved.

[0075] Viewed along the insertion direction of the press-fit terminal 20, the outward-facing portion of the parallel portion 36 is formed as an outwardly protruding arc-shaped surface 36f. If the outward-facing portion of the parallel portion 36 is formed as an arc-shaped surface 36f, it is expected that the arc-shaped surface 36f will contact the inner peripheral surface of the through hole 13 with a larger area.

[0076] The radius of curvature r of the arc-shaped surface 36f is preferably the same as, or smaller than, the inner circumferential radius (φ / 2) of the through hole 13 into which the press-fit terminal 20 is inserted. If the radius of curvature r of the arc-shaped surface 36f is the same as the inner circumferential radius (φ / 2) of the through hole 13, it is expected that the arc-shaped surface 36f will be in contact with the inner circumferential surface of the through hole 13 as a whole. Furthermore, the fact that the radius of curvature r of the arc-shaped surface 36f is the same as the inner circumferential radius (φ / 2) of the through hole 13 can also be included within the same manufacturing tolerance range. For example, the radius of curvature r of the arc-shaped surface 36f can also be the same as the inner circumferential radius (φ / 2) of the through hole 13 within an tolerance range of ±20%. Furthermore, even when the radius of curvature r of the arc-shaped surface is smaller than the inner circumferential radius (φ / 2) of the through hole 13, compared to the case where the radius of curvature r of the arc-shaped surface 136f is larger than the inner circumferential radius (φ / 2) of the through hole 13, it is expected that the central curved portion of the arc-shaped surface 36f will contact the inner circumferential surface of the through hole 13 with a larger area (see reference). Figure 3 The range is E1). This is because, for example, suppose if... Figure 4 If the radius of curvature r of the arc-shaped surface 136f is greater than the inner circumferential radius (φ / 2) of the through hole 13, then the two edges of the arc-shaped surface 136f will contact the inner circumferential surface of the through hole 13 with a smaller area than in the case described above (refer to...). Figure 4 (range E2). Even if the radius of curvature r of the arc surface is set to be less than the inner circumferential radius (φ / 2) of the through hole 13, the radius of curvature r of the arc surface is preferably more than 70% of the inner circumferential radius (φ / 2) of the through hole 13.

[0077] The outward-facing portions of the front spring portion 35 and the rear spring portion 37 also have the same curved surface as described above.

[0078] Viewed along the insertion direction of the press-fit terminal 20, it is not necessary for the outward portions of the parallel portion 36, the front spring portion 35, and the rear spring portion 37 to be formed in the aforementioned shape. For example, the outward portions of the parallel portion 36, the front spring portion 35, and the rear spring portion 37 may also be formed as planes. Furthermore, it is not excluded that... Figure 4 As shown, the radius of curvature r of the arc surface 136f is greater than the inner circumferential radius (φ / 2) of the through hole 13.

[0079] The thickness of the press-fit portion 30 is formed to be 0.3 mm or more and 0.5 mm or less. Preferably, the thickness of the press-fit portion 30 is 0.4 mm. By making the thickness of the press-fit portion 30 relatively small, at 0.3 mm or more and 0.5 mm or less, it is possible to accommodate small through holes 13. If the through holes 13 and the press-fit portion 30 are miniaturized, requirements such as high density and multi-polarity of the press-fit terminals 20 can be met.

[0080] Regarding the aforementioned pressing section 30, the size and shape of each part are designed as follows.

[0081] First, regarding the press-fit section 30, when the length of the eyelet 31 is set to Le [mm] and the length of the parallel section 36 is set to Ls [mm], Ls / Le is 0.57 or more and 0.65 or less. Here, the length Le [mm] of the eyelet 31 is the distance between the foremost front end and the rearmost rear end of the eyelet 31 in the front-rear direction. Furthermore, the length Ls [mm] of the parallel section 36 is the length of the straight outer edge 36a of the parallel section 36 in the front-rear direction.

[0082] Furthermore, regarding the press-fit section 30, the front spring strength calculated under the following conditions is set as G1 [mm]. 3 ], and set the rear spring strength to G2 [mm] 3 When G1 / G2 is above 0.55 and below 1.45.

[0083] [condition]

[0084] First, set the front reference SF at a position 0.1mm backward from the front end of the eyelet 31. Figure 1 In this context, the front reference SF is represented as a straight line orthogonal to the front-rear direction. Similarly, the rear reference SR is set 0.1 mm forward from the rear end of the eyelet 31. Figure 1 In this context, the rear reference SR is represented as a straight line orthogonal to the front and rear directions.

[0085] Assume a front reference surface TF perpendicular to the outer edge 35a of the front spring portion 35 at the front reference SF. Here, the front reference surface TF perpendicular to the outer edge 35a of the front spring portion 35 means the front reference surface TF perpendicular to the outer edge 35a of the front spring portion 35 as can be observed when viewing the press-fit portion 30 along its thickness direction. Let the moment of inertia of the section of the front spring portion 35 at this front reference surface TF be I1 [mm]. 4 ].

[0086] Similarly, assuming a rear reference plane TR perpendicular to the outer edge 37a of the rear spring portion 37 at the aforementioned rear reference SR, the moment of inertia of the section of the rear spring portion 37 at this rear reference plane TR is set as I2 [mm]. 4 ].

[0087] Furthermore, the length of the press-fit portion 30 in the insertion direction from the end of the straight outer edge 36a of the parallel portion 36 to the front end of the eyelet 31 is set to L1 [mm].

[0088] In addition, the length of the press-fit portion 30 in the insertion direction from the end of the straight outer edge 36a of the parallel portion 36 on the side of the rear spring portion 37 to the rear end of the eyelet 31 is set to L2 [mm].

[0089] Furthermore, the front spring strength G1 is defined as I1 / L1 [mm]. 3 The rear spring strength G2 is defined as I2 / L2 [mm]. 3 ].

[0090] [Regarding the moment of inertia of a cross section]

[0091] The moments of inertia of the sections at the aforementioned front reference plane TF and rear reference plane TR can be calculated, for example, in the following manner.

[0092] The cross-sectional shape of the front spring portion 35 at the front reference surface TF is, for example, as shown in the figure. Figure 5 The diagram shows the shape formed by combining a first rectangular part A with a second part B obtained by cutting off a portion of a circle with a straight line. Therefore, the moment of inertia of the section at the front reference plane TF can be considered as the sum of the moment of inertia of the first part A and the moment of inertia of the second part B.

[0093] In this cross-sectional shape, if the thickness of the press-fit part 30 is set to t [mm], the radius of curvature of the outward part of the press-fit part 30 is set to r [mm], and the dimension from the inward part to the outward part on the side of the eyelet 31 is set to the spring thickness h [mm], then the moment of inertia of the cross section at the front reference surface TF is calculated by the following formula.

[0094] [Formula 1]

[0095] I = {yy} a ) 2 S a +I a}+{(yy b ) 2 S b +I b}

[0096] in,

[0097]

[0098] Furthermore, in the above formula, I a It is the moment of inertia of section A in the first part, I. b This is the moment of inertia of section B in the second part. Additionally, S... a S is the cross-sectional area of ​​the first part A. b This is the cross-sectional area of ​​part B in the second section. Furthermore, y a It is the position of the neutral axis of part A, y b y is the position of the neutral axis of the second part B, and y is the position of the neutral axis of the whole that combines the first part A and the second part B.

[0099] The moment of inertia of the section at the rear reference plane TR can also be calculated in the same way as above.

[0100] The above-described method for calculating the moment of inertia of a cross section is an example. The moment of inertia of a cross section can be calculated using a method based on the cross-sectional shape of the front spring portion 35 at the front reference plane TF and the cross-sectional shape of the rear spring portion 37 at the rear reference plane TR.

[0101] With the press-fit terminal 20 configured in this way, Ls / Le is 0.57 to 0.65 and G1 / G2 is 0.55 to 1.45, thus improving the balance between reducing insertion force and increasing retention force.

[0102] At the aforementioned press-fit terminal 20, the spring strength G [mm] is... 3 When set to G1+G2, G can also be set to 0.03mm. 3 Above 0.04mm 3 The following further improves the balance between reducing insertion force and increasing retention force.

[0103] Furthermore, the outer edge 35a of the front spring portion 35 is inclined toward the inner side of the width direction of the press-fit portion 30 as it moves forward, and the outer edge 37a of the rear spring portion 37 is inclined toward the inner side of the width direction of the press-fit portion 30 as it moves backward. Therefore, if the press-fit terminal 20 is pressed into the through hole 13, the front spring portion 35 and the rear spring portion 37, which have outer edges 35a and 37a inclined relative to the parallel portion 36, can be easily deformed at both ends of the parallel portion 36.

[0104] In addition, since the outward-facing portion of the parallel portion 36 is formed as an arc-shaped surface 36f, the parallel portion 36 can easily contact the inner peripheral surface of the through hole 13 with a larger surface area, thus enabling a larger contact area.

[0105] In particular, if the radius of curvature r of the arc surface 36f is the same as or smaller than the radius of the through hole 13, the central part of the arc surface 36f can easily contact the inner circumferential surface of the through hole 13 with a larger area, thus making the contact area larger.

[0106] Figure 6 This diagram illustrates a connector assembly 50 that presses the aforementioned crimp terminal 20 into the substrate 12. The connector assembly 50 includes the substrate 12 and a connector 60. The connector 60 includes the aforementioned crimp terminal 20. Figure 6 In this connector 60, the connector terminal portion 54 is integrally connected to the base end portion 26 of the crimp terminal 20. The connector terminal portion 54 is connected to the base end portion 26 in a bent state (here, bent at a right angle). The base end portion of the crimp terminal 20 and the connector terminal portion 54 are inserted into the connector housing 61 of the connector 60. The base end portion may also protrude from the connector housing 61. The connector terminal portion 54 is arranged to protrude from the bottom opening of the space inside the connector housing 61. Here, multiple crimp terminals 20 are inserted into the connector housing 61. Therefore, within the connector housing 61, multiple connector terminal portions 54 stand side by side with gaps. In addition, multiple crimp terminals 20 protrude from the outer surface of the connector housing 61. Furthermore, multiple crimp terminals 20 protruding from the outer surface of the connector housing 61 are simultaneously pressed into multiple through holes 13. With multiple crimp terminals 20 pressed into multiple through holes 13, the connector 60 is mounted and fixed to the substrate 12.

[0107] The housing 52 is frame-shaped, having a space capable of accommodating the substrate 12. An opening 53 is formed on the housing 52, exposing the connector housing 61 to the outside. With the connector housing 61 disposed within the opening 53, the substrate 12 is fixed within the housing 52. The substrate 12 can be fixed within the housing 52 using a threaded locking mechanism, an insert mechanism, or a combination thereof.

[0108] In the connector assembly 50 described above, it is sometimes possible to insert multiple connector terminals 54 into the connector 60. In this case, it is possible to simultaneously press multiple crimp terminals 20 into the through hole 13. In such a case, the multiple crimp terminals 20 are effective in increasing the contact load and reducing the maximum value of the insertion force.

[0109] Furthermore, if the radius of curvature r of the outward-facing portion of the parallel portion 36 is the same as or smaller than the inner circumferential radius of the through hole 13, the contact area between the press-fit portion 30 and the inner circumferential surface of the through hole 13 will increase.

[0110] [Example]

[0111] In this embodiment, the evaluation of the insertion depth, holding force, and contact area of ​​the press-fit terminal 20 described in the above embodiments will be explained. The evaluation was derived using CAE (Computer Aided Engineering) analysis based on the finite element method.

[0112] Regarding the press-fit terminal 20, the values ​​of Ls / Le, G1 / G2, and G (=G1+G2) were changed for evaluation. Additionally, the thickness of the press-fit terminal 20 is 0.4 mm, and the diameter φ of the through hole 13 is 0.55 mm.

[0113] exist Figure 7 The evaluation results are shown in the figure. As can be seen from the figure, in Examples 1 and 2, where Ls / Le is 0.57 to 0.65 and G1 / G2 is 0.55 to 1.45, a high level of balance is achieved between reducing insertion force and increasing retention force and contact area. For example, in Examples 1 and 2, an insertion force of 63 N or less, a retention force of 20 N or more, and a contact area of ​​0.49 mm are achieved. 2 That's all. Even beyond this condition, adding G (=G1+G2) of 0.03mm... 3 Above 0.04mm 3 The following also allows for a high-level balance between reducing insertion force and increasing retention force and contact area. Furthermore, if G(=G1+G2) is 0.034mm 3 Above 0.037mm 3 The following theory suggests that it is possible to achieve a high level of balance between reducing insertion force and increasing retention force and contact area.

[0114] Furthermore, the structures described in the above embodiments and variations can be appropriately combined as long as they do not contradict each other.

[0115] Explanation of reference numerals in the attached figures

[0116] 12 substrate

[0117] 13 Through holes

[0118] 13f conductive layer

[0119] 20 Press-fit terminals

[0120] 22 Front end

[0121] 22a Foremost end

[0122] 26. Base end

[0123] 30 Pressing and Assembly Section

[0124] 31 holes

[0125] 34 contact pads

[0126] 35 Front Spring Section

[0127] 35a, 36a, 37a Outer edge

[0128] 36 Parallel Department

[0129] 36f, 136f curved surfaces

[0130] 37 Rear Spring Section

[0131] 50 Connector Assembly

[0132] 52. Housing

[0133] 53 Opening

[0134] 54 Connector Terminal Section

[0135] 60 connector

[0136] 61 Connector Housing

[0137] Part A

[0138] Part B

[0139] TF front reference plane

[0140] TR back reference plane.

Claims

1. A press-fit terminal, pressed into a through-hole formed in a substrate, The press-fit terminal includes a press-fit portion comprising two contact tabs facing each other with holes spaced apart. The two contact pieces each include: parallel portions that are parallel to each other, a front spring portion extending from the parallel portions in the direction of insertion into the press-fit portion, and a rear spring portion extending from the parallel portions in the direction opposite to the direction of insertion into the press-fit portion. The thickness of the press-fit section is 0.3 mm to 0.5 mm. Regarding the press-fit section, when the length of the orifice is set to Le and the length of the parallel section is set to Ls, Ls / Le is 0.57 or more and 0.65 or less, wherein... The unit for Le is mm, and the unit for Ls is mm. Regarding the press-fit part, when the front spring strength calculated under the following conditions is set as G1 and the rear spring strength is set as G2, G1 / G2 is 0.55 or more and 1.45 or less, where the unit of G1 is mm. 3 The unit for G2 is mm. 3 , The conditions are: • Set the direction of insertion of the crimp terminal to forward, and set the direction opposite to the insertion direction to backward; • The position 0.1mm backward from the front end of the hole is set as the front reference, and the position 0.1mm forward from the rear end of the hole is set as the rear reference; • Assuming a front reference plane perpendicular to the inner edge and outer edge of the front spring portion at the front reference point, the moment of inertia of the front spring portion section at this front reference plane is defined as I1, where the unit of I1 is mm. 4 ; • Assuming a rear reference plane perpendicular to the inner edge and outer edge of the rear spring portion at the rear reference point, the moment of inertia of the section of the rear spring portion at this rear reference plane is defined as I2, where the unit of I2 is mm. 4 ; • The length of the press-fit part in the insertion direction from the end of the front spring part on the straight outer edge of the parallel part to the front end of the eyelet is defined as L1, where the unit of L1 is mm; • The length of the press-fit part in the insertion direction from the end of the rear spring portion in the straight outer edge of the parallel portion to the rear end of the eyelet is defined as L2, where the unit of L2 is mm; • Set the front spring strength G1 as I1 / L1, where I1 / L1 is in mm. 3 Let the spring strength G2 on the rear side be I2 / L2, where the unit of I2 / L2 is mm. 3 .

2. The press-fit terminal according to claim 1, wherein, When the spring strength G is set to G1+G2, G is 0.03mm. 3 Above 0.04mm 3 In the following, the unit of G is mm. 3 .

3. The press-fit terminal according to claim 1, wherein, The outer edge of the front spring portion is inclined toward the inside of the width direction of the press-fit portion as it moves forward. The outer edge of the rear spring portion is inclined inward toward the width direction of the press-fit portion as it moves rearward.

4. The press-fit terminal according to claim 2, wherein, The outer edge of the front spring portion is inclined toward the inside of the width direction of the press-fit portion as it moves forward. The outer edge of the rear spring portion is inclined inward toward the width direction of the press-fit portion as it moves rearward.

5. The press-fit terminal according to any one of claims 1 to 4, wherein, The outward-facing portion of the parallel section forms an arc shape when viewed along the insertion direction.

6. A connector device comprising: Connector, comprising the press-fit terminal as described in claim 5; and The substrate has through holes. The crimping portion of the crimping terminal is pressed into the through hole. When viewed along the insertion direction, the radius of curvature of the outward-facing portion of the parallel section is the same as or smaller than the inner circumferential radius of the through hole.

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