Terminal manufacturing method

Abstract

To improve the elastic limit or the spring contact pressure of a cantilever-like terminal.SOLUTION: A terminal 1 has a movable piece 3 that extends in a cantilever manner from a base 2 formed of a metal plate while being inclined by a spring angle θ with respect to the base 2, and is deformed in a deflection direction that is a direction to cancel the inclination to apply a contact pressure to a mating terminal 90. A method for manufacturing the terminal 1 includes: a bending step S31 of pressing the movable piece 3 in the reverse deflection direction opposite to the deflection direction in a state where the movable piece 3 extends from the base 2 without inclination, and bending the movable piece 3 in the reverse deflection direction by an initial bending amount θ1 to plastically deform the movable piece 3; and a bend-back step S33 of pressing the movable piece 3 in the deflection direction to bend back the movable piece by a bend-back amount θ2 smaller than the initial bending amount θ1 to plastically deform the movable piece 3.SELECTED DRAWING: Figure 6C

Description

Technical Field

[0001] The present invention relates to a method for manufacturing terminals.

Background Art

[0002] Patent Document 1 discloses a metal connector terminal. The terminal has a movable piece formed by stamping, and the movable piece is in the shape of a cantilever beam. Considering the sag of the movable piece due to the Bauschinger effect and the decrease in spring contact pressure, the fulcrum portion of the movable piece has a shape that is pushed upward toward the outside, that is, it is pushed upward in the direction opposite to the deflection direction of the movable piece during use.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There is still room for improvement in the terminals with respect to the elastic limit or spring contact pressure.

[0005] An object of the present invention is to improve the elastic limit or spring contact pressure of a cantilever beam-shaped terminal.

Means for Solving the Problems

[0006] One aspect of the present invention provides a method for manufacturing a terminal having a movable piece that extends from a base made of a metal plate at a spring angle and cantilevered, and applies contact pressure to a mating terminal by deforming in a bending direction which is the direction in which the inclination is eliminated, comprising: a bending step in which the movable piece is pressed in the opposite direction to the bending direction while the movable piece is extending from the base without inclination, bending the movable piece by an initial bending amount in the opposite direction to the bending direction, and plastically deforming the movable piece; and a bending back step in which the movable piece is pressed in the bending direction, and bent back by a bending back amount smaller than the initial bending amount, and plastically deforms the movable piece.

[0007] According to the above configuration, the movable piece is first bent in the opposite direction of deflection, and then bent back in the direction of deflection. Since the amount of bending back is smaller than the initial bending amount, the spring angle is maintained. In the later stages of processing, the movable piece is bent back in the same direction as the deformation direction during use. Therefore, work hardening occurs at the base of the movable piece, and the occurrence of the Bauschinger effect during use can be suppressed. The elastic limit can be increased while maintaining a high rate of change of load (elastic modulus) with respect to terminal displacement. The design range of the terminal is expanded, and an appropriate or high spring contact pressure can be applied to the mating terminal.

[0008] The bending process and the unbending process may further include a first springback process, in which the movable piece is subjected to unloading to generate springback in the direction of deflection, and a second springback process, in which the movable piece is subjected to unloading after the unbending process to generate springback in the opposite direction of deflection.

[0009] According to the above configuration, the movable piece is bent to account for springback, and the spring angle can be appropriately set or controlled.

[0010] The amount of bending back may be greater than the amount of deformation of the movable piece from its natural state due to contact with the mating terminal.

[0011] According to the above configuration, a decrease in spring contact pressure performance due to sagging can be prevented, and the elastic limit and spring contact pressure can be improved.

Advantages of the Invention

[0012] According to the present invention, the elastic limit or spring contact pressure of the cantilever beam-shaped terminal can be improved.

Brief Description of the Drawings

[0013] [Figure 1] Front view of the terminal according to the embodiment. [Figure 2A] Cross-sectional view taken along line II-II of FIG. 1, showing the terminal in the natural state together with the mating terminal during the insertion / extraction process. [Figure 2B] Cross-sectional view showing the terminal and the mating terminal in the connected state. [Figure 3] Flowchart showing the manufacturing method of the terminal according to the embodiment. [Figure 4A] Perspective view showing the blank shape after the trimming process and the coining process. [Figure 4B] Perspective view showing the blank shape after the tip bending process. [Figure 4C] Perspective view showing the blank shape after the root bending process. [Figure 5A] Front view showing the blank shape after the root bending process. [Figure 5B] Front view showing the blank shape after the outer bending process. [Figure 5C] Front view showing the blank shape after the inner bending process. [Figure 5D] Front view showing the blank shape after the box bending process is completed. [Figure 6A] Side view showing the bending process. [Figure 6B] Side view showing the first springback process. [Figure 6C] Side view showing the bending return process. [Figure 6D] Side view showing the second springback process. [Figure 7] Graph for explaining the spring contact pressure.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or corresponding elements are denoted by the same reference numerals throughout the drawings, and redundant detailed descriptions are omitted.

[0015] Referring to FIGS. 1 and 2A, terminal 1 is formed from a metal plate having conductivity. A strip of copper alloy is suitable as the material for terminal 1 because it has excellent conductivity, strength, ductility, and solder wettability. The copper alloy may be subjected to a plating treatment that does not inhibit conductivity, for example, it may be tin-plated, silver-plated, or gold-plated.

[0016] Terminal 1 is female and is in the shape of a box or rectangular cylinder that is open at both ends. Terminal 1 is housed in a synthetic resin housing (not shown) having electrical insulation properties and constitutes a female connector. An opening on one side in the longitudinal direction X (the direction perpendicular to the plane of FIG. 1 and the left-right direction of the plane of FIG. 2A) of terminal 1 is terminal insertion port 1a. Mate terminal 90 is male and is flat. Mate terminal 90 is inserted into terminal 1 from the outside of terminal 1 through terminal insertion port 1a. The material of mate terminal 90 is not particularly limited as long as it has conductivity.

[0017] The width direction Y of terminal 1 is a direction perpendicular to the longitudinal direction X of terminal 1, and the height direction Z of terminal 1 is a direction perpendicular to both the longitudinal direction X and the width direction Y of terminal 1. The longitudinal direction X corresponds to the insertion / removal direction of mate terminal 90. When mate terminal 90 is inserted into and removed from terminal 1, the width direction of mate terminal 90 is oriented in the width direction Y of terminal 1, and the plate thickness direction of mate terminal 90 is oriented in the height direction Z of terminal 1.

[0018] In the following description, for the sake of convenience of explanation only, the longitudinal direction X and the width direction Y are taken as horizontal, one side in the longitudinal direction X (the side where terminal insertion port​​​Terminal 1 comprises a base 2, a movable piece 3, and protrusions 4a and 4b.

[0020] The base 2 is a rectangular box or cylindrical body enclosed on four sides and having a double bottom, with openings at both ends. The base 2 has an outer bottom wall 2a, a first side wall 2b, a top wall 2c, a second side wall 2d, and an inner bottom wall 2e. These walls 2a to 2e are all plate-like and extend in the longitudinal direction X, and are continuous in a seamless manner.

[0021] The outer bottom wall 2a extends in the width direction Y. The first side wall 2b extends from one edge of the outer bottom wall 2a in the width direction Y (right side of the paper in Figure 1) to one side in the height direction Z (upper side). The top wall 2c extends from the upper edge of the second side wall 2d to the other side in the width direction Y (left side of the paper in Figure 1). The second side wall 2d extends from the other edge of the top wall 2c in the width direction Y to the other side in the height direction Z (lower side). The inner bottom wall 2e extends from the lower edge of the top wall 2c to one side in the width direction Y. The inner bottom wall 2e is superimposed on the outer bottom wall 2a with a small gap from its upper surface, and is also opposite the top wall 2c in the height direction Z with a gap equivalent to the height of the second side wall 2d.

[0022] The outer bottom wall 2a, the top wall 2c, and the inner bottom wall 2e are parallel to each other and extend horizontally. The first side wall 2b and the second side wall 2d are parallel to each other and extend vertically, facing each other in the width direction Y with a gap corresponding to the width of the top wall 2c. The outer surface of the second side wall 2d is substantially flush with the other end surface of the outer bottom wall 2a in the width direction Y, and the lower end of the second side wall 2d is close to the upper surface of the outer bottom wall 2a. One end surface of the inner bottom wall 2e in the width direction Y is close to the inner surface of the first side wall 2b.

[0023] The movable piece 3 extends rearward from the inner bottom wall 2e, inclined upward from the base 2. The movable piece 3 has a leaf spring portion 3a that is continuous with the inner bottom wall 2e, and a tip portion 3b that is continuous with the tip of the leaf spring portion 3a. The tip portion 3b is formed by bending the tip of the leaf spring portion 3a. The tip portion 3b extends rearward from the tip of the leaf spring portion 3a, inclined downward.

[0024] The projection 4a is provided on the movable piece 3. For example, the projection 4a is positioned at the corner between the leaf spring portion 3a and the tip portion 3b, and protrudes upward. The projection 4b is provided on the top wall 2c. For example, the projection 4b is positioned in the longitudinal direction X at a location corresponding to the projection 4a, and protrudes downward from the top wall 2c. Note that there may be multiple projections 4b in the width direction Y (for example, two) (see Figure 1), and / or multiple projections 4b in the longitudinal direction X (for example, two) (see Figure 2A).

[0025] In the following explanation, the state in which the mating terminal 90 is not inserted into terminal 1 is referred to as the "natural state." The corner between the inclined leaf spring portion 3a and the horizontal inner bottom wall 2e is referred to as the "base of the movable piece 3."

[0026] Referring to Figure 1, "spring width W" is the width dimension Y of the movable piece 3. In this embodiment, the spring width W is constant from the base to the tip of the movable piece 3. "Gap G" is the distance in the height direction Z between the tip of projection 4a (the apex that protrudes upward) and the tip of projection 4b (the apex that protrudes downward). Referring to Figure 2A, "spring length L" is the length dimension X of the leaf spring portion 3a in its natural state. "Spring angle θ" is the angle formed by the extending direction of the leaf spring portion 3a and the extending direction of the inner bottom wall 2e in its natural state.

[0027] In its natural state, the gap G is smaller than the plate thickness of the mating terminal 90. When the mating terminal 90 is inserted into terminal 1, the tip of the mating terminal 90 abuts against the upper side of the movable piece 3. As the rearward insertion of the mating terminal 90 progresses, the leaf spring portion 3a elastically deforms, using the base of the movable piece 3 as a fulcrum, to eliminate the downward inclination from its natural state. As a result, the gap G widens and the spring angle θ decreases. As shown in Figure 2B, when the insertion of the mating terminal 90 is complete, the upper surface of the mating terminal 90 contacts the projection 4b of the top wall 2c, and the lower surface of the mating terminal 90 contacts the projection 4a of the movable piece 3. As a result, terminal 1 and the mating terminal 90 become electrically connected. The leaf spring portion 3a presses the mating terminal 90 upward to return to its natural state. As a result, the mating terminal 90 is held between the projections 4a and 4b, and the mating terminal 90 is mechanically connected to terminal 1. When the mating terminal 90 is pulled forward, the movable piece 3 returns to its natural state.

[0028] In the following explanation, the direction in which the movable piece 3 elastically deforms when the mating terminal 90 is inserted may be referred to as the "bending direction." Also, the direction in which the movable piece 3 returns from the bent state to its natural state when the mating terminal 90 is withdrawn may be referred to as the "opposite bending direction." The bending direction corresponds to the other side (downward) of the height direction Z, and the opposite bending direction corresponds to the one side (upward) of the height direction Z. Furthermore, the state in which terminal 1 and the mating terminal 90 are electrically conductive and mechanically connected is referred to as the "connected state." The force or pressure that the movable piece 3 applies to the mating terminal 90 in the connected state is referred to as the "spring contact pressure."

[0029] Figure 3 is a flowchart showing the manufacturing method of terminal 1. In the manufacturing of terminal 1, the trimming process S1, coining process S2, spring bending process S3, and box bending process S4 are performed in this order. The spring bending process S3 includes a tip bending process S3a (see Figure 4B) and a root bending process S3b (see Figure 4C). The root bending process S3b includes a bending process S31 (see Figure 6A), a first springback process S32 (see Figure 6B), a straightening process S33 (see Figure 6C), and a second springback process S34 (see Figure 6D). The box bending process S4 includes an outer bending process S41 (see Figure 5B) and an inner bending process S42 (see Figure 5C). In the following description, the reference numerals for each of the above processes will be used without specifically referring to Figure 3.

[0030] As shown in Figure 4A, in the trimming process S1, a metal (e.g., copper alloy) sheet material is punched out to form a blank 20. The blank 20 is rectangular in shape and has the size required for manufacturing the terminal 1. The length of the long side of the blank 20 corresponds to the sum of the lengths of the five walls 2a to 2e of the base 2 of the terminal 1 as a finished product. The direction of the short side of the blank 20 corresponds to the longitudinal direction X of the terminal 1 as a finished product.

[0031] In the trimming process S1, a notch 21 is formed in the blank 20. The notch 21 is rectangular in shape and is open at the long edge on the other side of the blank 20 (the upper side of the paper in Figure 4A, the rear side of the terminal 1 as a finished product). A strip-shaped portion remains on one side of the blank 20 in the direction of the long edge relative to the notch 21 (the right side of the paper in Figure 4A). This portion is bent in the spring bending process S3, and plays the role of a movable piece 3 in the terminal 1 as a finished product.

[0032] In the coining process S2, protrusions 4a and 4b are formed by extending minute hemispheres (including semi-ellipsoids) from the blank 20. In addition, multiple grooves 22a, 22b, 22c, and 22d are formed on one side of the blank 20. The number of grooves is one less than the number of walls of the base 2. In this embodiment, the base 2 has five walls 2a to 2e, and four grooves 22a to 22d are formed in the blank 20. The four grooves 22a to 22d extend parallel to the short side direction of the blank 20 (the longitudinal direction X of the terminal 1 as a finished product) and are spaced apart in the long side direction of the blank 20.

[0033] Five sections are demarcated by four grooves 22a to 22d and arranged along the long side of the blank 20. In the box bending process S4, the blank is bent using each groove 22a to 22d as a pivot point, and these five sections each play the role of five walls 2a to 2e that form the base 2 of the terminal 1 as a finished product.

[0034] Thus, the trimming process S1 and the coining process S2 are processes for forming or preparing a base 2 having five walls 2a to 2e, and for forming or preparing a movable piece 3 that extends from such base 2 in a cantilevered manner and has a leaf spring portion 3a and a tip portion 3b. As described below, the leaf spring portion 3a and the tip portion 3b are then formed in the spring bending process S3, and the five walls 2a to 2e are formed in the box bending process S4.

[0035] As shown in Figure 4B, in the tip bending process S3a of the spring bending process S3, the tip portion 3b of the movable piece 3, which extends integrally with the inner bottom wall 2e, is bent.

[0036] As shown in Figures 4C and 5A, in the root bending process S3b of the spring bending process S3, the leaf spring portion 3a of the movable piece 3 is bent. The leaf spring portion 3a is bent together with the tip portion 3b to the inner bottom wall 2e by a spring angle θ (see Figures 2A and 6D) relative to the inner bottom wall 2e.

[0037] As shown in Figure 5B, in the outer bending process S41 of the box bending process S4, the groove 22a at the end of one side in the longitudinal direction of the blank 20 is used as a fulcrum, and the portion further to the other side in the longitudinal direction is pressed from the back surface of the blank 20 (the surface opposite to the surface where the groove 22a is formed). This forms the outer bottom wall 2a which is bent relative to the first side wall 2b. The groove 22d at the end of the other side in the longitudinal direction of the blank 20 is used as a fulcrum, and the portion further to the other side in the longitudinal direction is pressed from the back surface of the blank 20. This forms the inner bottom wall 2e. At this stage, the bending angles of the outer bottom wall 2a and the inner bottom wall 2e with respect to the first side wall 2b and the second side wall 2d, respectively, are obtuse angles.

[0038] As shown in Figure 5C, next, using the groove 22b on one side of the center of the long side of the blank 20 as a fulcrum, the portion on the one side of the long side from this point is pressed from the back of the blank 20. This forms a first side wall 2b that is bent relative to the top wall 2c. Then, using the groove 22c on the other side of the center of the long side of the blank 20 as a fulcrum, the portion on the other side of the long side from this point is pressed from the plane of the blank 20. This forms a second side wall 2d that is bent relative to the top wall 2c.

[0039] As shown in Figure 5D, the blank 20 is bent such that the inner bottom wall 2e is positioned inside the outer bottom wall 2a and the bending angles in each groove 22a, 22b, 22c, and 22d are approximately right angles. This completes the terminal 1. The orientation of the terminal 1 during use and the orientation during manufacturing do not need to be the same; for example, they may be reversed in the height direction Z, as shown in Figures 1 and 5D.

[0040] Referring to Figures 6A to 6D, the root bending process S3b in the spring bending process S3 will be explained.

[0041] Referring to Figure 6A, after the tip bending process S3a (see Figures 3 and 4B), the bending process S31 is performed as the first step of the root bending process S3b. In the bending process S31, the leaf spring portion 3a of the movable piece 3 is bent in the opposite direction to the deflection relative to the inner bottom wall 2e of the base portion 2, causing plastic deformation in the leaf spring portion 3a.

[0042] For the bending process S31, a blank hold 81, a die face 82, and a punch 83 are used. The blank hold 81 and die face 82 are fixed, while the punch 83 is movable in the height direction Z. The blank hold 81 and punch 83 support the blank 20 from below and are aligned in the longitudinal direction X. The die face 82 is located above the blank hold 81 and punch 83 (i.e., on the other side of the height direction Z, opposite to the direction of deflection).

[0043] The upper surface of the blank hold 81 is a support surface 81a that supports the inner bottom wall 2e. The upper surface of the punch 83 is a pressing surface 83a that presses the leaf spring portion 3a from below upward. The die face 82 has a clamping surface 82a that faces the support surface 81a of the blank hold 81 in the height direction Z, and a pressure receiving surface 82b that extends continuously from the clamping surface 82a in the longitudinal direction X and faces the pressing surface 83a of the punch 83 in the height direction Z.

[0044] The support surface 81a and the clamping surface 82a are parallel to each other (e.g., horizontal) and close to each other. The pressure-receiving surface 82b is inclined upward as it moves away from the clamping surface 82a in the longitudinal direction X. The pressing surface 83a of the punch 83 is parallel to the pressure-receiving surface 82b of the die face 82 and is inclined with respect to the support surface 81a of the blank hold 81.

[0045] At the beginning of the bending process S31, the punch 83 is retracted downward. The inner bottom wall 2e is placed on the support surface 81a and is clamped between the support surface 81a and the clamping surface 82a. On the other hand, the movable piece 3 is not placed on the support surface 81a and extends in a cantilevered manner in the longitudinal direction X relative to the blank hold 81. The leaf spring portion 3a extends from the inner bottom wall 2e without inclination. The pressure-receiving surface 82b of the die face 82 is separated upward from the movable piece 3, and the pressing surface 83a of the punch 83 is separated downward from the movable piece 3.

[0046] As the punch 83 rises, the lower surface of the movable piece 3 is pressed against the pressing surface 83a of the punch 83, sequentially from the tip to the base of the movable piece 3. As a result, the movable piece 3 is bent upward, i.e., in the opposite direction of deflection, with its base as the pivot point. The leaf spring portion 3a is sandwiched between the pressing surface 83a and the pressure receiving surface 82b. The leaf spring portion 3a receives the load from the punch 83 while inclined upward by an initial bending amount θ1 relative to the inner bottom wall 2e. The initial bending amount θ1 corresponds to the inclination angle of the pressure receiving surface 82b of the die face 82 with respect to the clamping surface 82a, or the inclination angle of the pressing surface 83a of the punch 83 with respect to the support surface 81a of the blank hold 81.

[0047] Referring to Figure 6B, the first springback process S32 is performed or occurs by retracting the punch 83 downward. The movable piece 3 is unloaded, and the leaf spring portion 3a deforms downward (i.e., in the deflection direction) by the first springback amount Δθ1.

[0048] Next, referring to Figure 6C, the bending-back process S33 is performed. In the bending-back process S33, the leaf spring portion 3a of the movable piece 3 is bent in the deflection direction relative to the inner bottom wall 2e of the base portion 2, causing plastic deformation in the leaf spring portion 3a.

[0049] For the bending-back process S33, a blank hold 86, a restraining jig 87, and a punch 88 are used. The blank hold 86 and the restraining jig 87 are fixed, while the punch 88 is movable in the height direction Z. The blank hold 86 supports the blank 20 from below. The restraining jig 87 and the punch 88 are located above the blank hold 86 (i.e., on one side in the height direction Z, in the deflection direction) and are aligned in the longitudinal direction X. The upper surface of the blank hold 86 has a support surface 86a and a pressure-receiving surface 86b that is continuous with the support surface 86a. The pressure-receiving surface 86b is inclined upward as it moves away from the support surface 86a in the longitudinal direction X. The lower surface of the restraining jig 87 is a restraining surface 87a that faces the support surface 86a in the height direction Z. The lower surface of the punch 88 is a pressing surface 88a that presses the leaf spring portion 3a from top to bottom. The support surface 86a and the restraining surface 87a are parallel to each other (e.g., horizontal) and close to each other. The pressing surface 88a of the punch 88 is parallel to the pressure-receiving surface 86b of the blank hold 86 and is inclined with respect to the restraining surface 87a of the restraining jig 87.

[0050] At the beginning of the bending-back process S33, the punch 88 is retracted upward. The inner bottom wall 2e is placed on the support surface 86a and is held between the support surface 86a and the restraining surface 87a. The corner between the movable piece 3 and the inner bottom wall 2e is positioned at the edge of the support surface 86a. The leaf spring portion 3a is not placed on the support surface 86a and is separated upward from the pressure receiving surface 86b. The pressing surface 88a of the punch 88 is separated upward from the leaf spring portion 3a.

[0051] As the punch 88 descends, the upper surface of the movable piece 3 is pressed against the pressing surface 88a of the punch 88, sequentially from the tip end to the base end. As a result, the movable piece 3 is bent back downward, i.e., in the deflection direction, with its base as the pivot point. The leaf spring portion 3a is sandwiched between the pressing surface 88a and the pressure receiving surface 86b.

[0052] The leaf spring section 3a receives the load from the punch 88 while bent back downward (i.e., in the deflection direction) by a bending amount θ2 after the completion of the first springback process S32. The inclination angle of the pressure receiving surface 86b with respect to the support surface 86a, or the inclination angle of the restraining surface 87a with respect to the pressing surface 88a, corresponds to the value obtained by subtracting the first springback amount Δθ1 in the deflection direction from the initial bending amount θ1 in the opposite direction of deflection, and then further subtracting the bending amount θ2 in the deflection direction (θ1-Δθ1-θ2). Upon execution of the bending back process S33, the leaf spring section 3a receives the load from the punch 88 while inclined upward by this value (θ1-Δθ1-θ2) with respect to the inner bottom wall 2e.

[0053] Referring to Figure 6D, the second springback process S34 is performed or occurs by retracting the punch 88 upward. The movable piece 3 is unloaded, and the leaf spring portion 3a deforms upward (i.e., in the opposite direction of deflection) by the second springback amount Δθ2, with the base as the fulcrum.

[0054] As a result of the root bending process S3b, the leaf spring portion 3a extends upward (i.e., in the opposite direction of deflection) by a spring angle θ relative to the inner bottom wall 2e. The spring angle θ is approximately equal to the initial bending amount θ1 minus the bending return amount θ2. More precisely, the spring angle θ corresponds to the value obtained by subtracting the first springback amount Δθ1 from the subtracted value (θ1-θ2) and adding the second springback amount Δθ2 (θ1-θ2-Δθ1+Δθ2). Furthermore, throughout the root bending process S3b, the tip portion 3b is not subjected to load from the punches 83 and 88.

[0055] Furthermore, the amount of bending back θ2 is smaller than the initial bending amount θ1, thereby ensuring a spring angle θ in the opposite direction of deflection. The amount of bending back θ2 is larger than the amount of deflection deformation in the connected state.

[0056] Thus, the root bending process S3b includes a bending-back process S33 in which the leaf spring portion 3a is bent with the root portion as a fulcrum in the direction of deflection of the leaf spring portion 3a in the connected state. After this bending-back process S33, although springback occurs, bending in the opposite direction of deflection is not actively applied to the leaf spring portion 3a.

[0057] This suppresses the occurrence of the Bauschinger effect in the connected state. As a result, the elastic limit of the movable piece 3 is increased, and the movable piece 3 can exert an appropriate or high spring contact pressure against the mating terminal 90 in the connected state.

[0058] Figure 7 is an explanatory diagram of spring contact pressure. The horizontal axis shows the downward (bending direction) displacement (mm) of the movable piece 3 from its natural state. The vertical axis shows the load (N) applied to the movable piece 3. Line A shows the load for displacement in this embodiment, and lines B and C show the load for displacement in Comparative Example B and Comparative Example C, respectively.

[0059] In the diagram, "Gmin" represents the upper limit of the gap, and "Gmax" represents the lower limit of the gap. The upper and lower limits of the gap G are due to the variation in the gap G. The upper limit of the gap Gmin is the gap value when the gap G is widest, the minimum displacement from the natural state to the connected state (the minimum change in the gap G from the natural state). The lower limit of the gap Gmax is the gap value when the gap G is narrowest, the maximum displacement from the natural state to the connected state (the maximum change in the gap G from the natural state).

[0060] In the diagram, "Pmin" represents the minimum spring contact pressure. The minimum spring contact pressure Pmin is the spring contact pressure that should be applied from the movable piece 3 to the mating terminal 90 when the displacement of the movable piece 3 from the natural state to the connected state is equal to the upper limit of the gap Gmin.

[0061] EL(B) represents the elastic limit in Comparative Example B, represented by line B. EL(A) represents the elastic limit in this embodiment, represented by line A. The elastic limit may mean the limit of the load that can be elastically deformed, or it may mean the limit of the displacement that can be elastically deformed. In each of lines A to C, the load increases linearly with respect to displacement from a state where displacement and load are zero up to the elastic limit. When the displacement exceeds the elastic limit, plastic deformation occurs, and the load increases slowly and non-linearly with respect to displacement.

[0062] It is desirable that the movable piece 3 can exert a spring contact pressure on the mating terminal 90 that exceeds the minimum spring contact pressure Pmin when the displacement of the movable piece 3 from the natural state to the connected state is the upper limit of the gap Gmin (hereinafter referred to as characteristic (1)). Having such characteristic (1) allows the connected state to be maintained even if the plate thickness of the mating terminal 90 is thin.

[0063] It is desirable that the movable piece 3 does not undergo plastic deformation at the lower limit of the gap Gmax (hereinafter referred to as characteristic (2)). Having such characteristic (2) prevents the movable piece 3 from sagging even if the thickness of the mating terminal 90 is thick, and prevents a decrease in spring contact pressure performance due to sagging.

[0064] In comparative example B, represented by line B, characteristic (1) is present but characteristic (2) is not. Therefore, the allowable upper gap limit Gmin in comparative example B must be set lower than that shown in Figure 7. The range between the lower gap limit Gmax and the upper gap limit Gmim becomes narrower, and the design area for the terminal becomes narrower. When the Bauschinger effect occurs, the contact pressure characteristics become as shown by line B. Copper alloys are materials in which the Bauschinger effect is more likely to occur among metals, meaning that it is difficult to secure a wide design area. Therefore, it is possible to select a material with a small rate of change of load with respect to displacement. However, in that case, as shown by line C, it becomes easier to satisfy characteristic (2), but it becomes difficult or impossible to satisfy characteristic (1).

[0065] In contrast, in this embodiment represented by line A, the Bauschinger effect is suppressed while maintaining a high rate of change of load with respect to displacement. Therefore, the elastic limit EL(A) as displacement can be increased compared to the elastic limit EL(B) of comparative example B. Thus, it can have both characteristic (2) and characteristic (1).

[0066] Although embodiments have been described so far, the above configuration is merely an example and can be modified, added to, or deleted as appropriate within the scope of the present invention. [Explanation of symbols]

[0067] 1 terminal 1a Terminal insertion slot 2 base 2a Outer bottom wall 2b 1st side wall 2c ceiling wall 2d 2nd side wall 2e Inner bottom wall 3 Movable piece 3a Leaf spring section 3b Tip 4a,4b protrusion 20 Blank 21 Notches 22a,22b,22c,22d Groove 81,86 Blank Hold 82 die faces 83,88 punches 87 Restraint fixtures 90 Mating terminal G Gap L spring length W spring width θ Spring angle θ1 Initial bending amount Δθ1 First springback amount θ2 amount of bending back Δθ2 Second springback amount S1 Trimming process S2 Coining Process S3 Spring bending process S3a Tip bending process S3b Root bending process S31 Bending process S32 First springback process S33 Bending back process S34 Second springback process S4 Box Bending Process S41 Outside bending process S42 Inner bending process

Claims

1. A method for manufacturing a terminal having a movable piece that extends from a base made of a metal plate at a spring angle and cantilevered, and applies contact pressure to a mating terminal by deforming in a bending direction that eliminates the inclination, A bending process in which the movable piece is pressed in the opposite direction to the bending direction while the movable piece extends from the base without tilting, the movable piece is bent by an initial bending amount in the opposite direction to the bending, and the movable piece is plastically deformed. A bending back step in which the movable piece is pressed in the bending direction and bent back by an amount smaller than the initial bending amount, thereby causing plastic deformation of the movable piece, A method for manufacturing terminals, comprising:

2. Between the bending process and the unbending process, a first springback process is performed to generate springback of the movable piece in the bending direction by unloading, A second springback step is performed after the bending back step, in which the movable piece is springed back in the opposite direction to the deflection by unloading, A method for manufacturing a terminal according to claim 1, further comprising the above.

3. The amount of bending back is greater than the amount of deformation of the movable piece from its natural state due to contact with the mating terminal. A method for manufacturing a terminal according to claim 1.

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