Manufacturing method for metal terminals

Abstract

To provide a metal terminal capable of enhancing the sealing effect between a resin component and a metal terminal, and a method for manufacturing a metal terminal that can reduce manufacturing costs. [Solution] The manufacturing method for the metal terminal 10 involves forming a series of fine grooves 20 that are continuous around the entire circumference in the width direction at the joint 3 between the metal terminal 10 and the resin member 2. The first side stamping step forms a right side groove 21 and a left side groove 22 at a 2-pitch interval. The second side stamping step further forms the right side groove 21 and the left side groove 22 at a 1-pitch interval. The first front and back stamping step forms a front groove 23 and a back groove 24 at a 2-pitch interval. The second front and back stamping step further forms the front groove 23 and the back groove 24 at a 1-pitch interval.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a metal terminal coated with a resin member by insert molding and having both end portions in the longitudinal direction protruding from the resin member, and to a metal terminal formed by this method for manufacturing a metal terminal.

Background Art

[0002] There is a resin molded body in which a metal terminal is coated with a resin member and both end portions protrude from the resin member. In such a resin molded body, the metal terminal and the resin member are joined with different materials, and the joining strength of the joint between the resin member and the metal terminal may not be obtained. When the joining strength decreases, there is a risk that water, oil, etc. may leak from the joint portion. Conventionally, in order to prevent leakage of water, oil, etc., a resin material different from the resin member has been reinforced by potting or the like around the metal terminal protruding from the resin member. With such a configuration, in addition to the molding process of the resin molded body, a process related to potting is required.

[0003] In order to prevent leakage, it has been proposed to form irregularities on the surface of the joint portion between the metal terminal and the resin member by irradiating a laser beam (see, for example, Patent Document 1). It is said that by allowing the resin member to enter the irregularities formed in this joint portion, the metal terminal and the resin member can be strongly joined, and the sealing effect for preventing leakage of water, oil, etc. can be enhanced.

[0004] Also, it is disclosed that a plurality of V-grooves are formed in the joint portion between the metal terminal and the resin member (see, for example, Patent Document 2). In the metal terminal described in Patent Document 2, since the resin member is covered up to the inside of the V-groove of the metal terminal, the space between the metal terminal and the resin member is sealed. The linear thermal expansion coefficients of the resin member and the metal terminal are different, and a gap may be formed in the joint portion when the temperature rises. However, since the metal terminal is provided with V-grooves, it is said that even if the resin member thermally expands more than the metal terminal, the sealing effect can be maintained because there is a portion where the metal terminal and the resin member are in contact. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2019-119093 [Patent Document 2] Japanese Patent Publication No. 2018-99849 [Overview of the project] [Problems that the invention aims to solve]

[0006] The metal terminal described in Patent Document 1 above has irregularities formed on the surface of the joint. These irregularities are first formed by irradiating the surface of the metal terminal with a laser beam, and then forming second irregularities by irradiating the surface of the first irregularities with a laser beam. The joint strength is obtained by the resin material filling the recesses of the formed irregularities. An expensive laser irradiation device is required to form irregularities on the metal terminal. In addition, an irradiation position switching device is required to switch the orientation of the metal terminal in order to uniformly irradiate the four surfaces of the metal terminal with a laser beam. Furthermore, the laser beam irradiation section requires a compartment equipped with an air exhaust device to remove dust and other debris. As a result of the above, there are problems such as the irregularity formation device becoming complex, the cycle time becoming long, and the manufacturing cost of the metal terminal becoming high.

[0007] Furthermore, when insert molding metal terminals, vacuum void connections may occur around the joint as the resin component cools. Vacuum void connections are known to reduce joint strength. The joint strength of the metal terminals in Patent Document 1 depends on a second set of irregularities with a height of 0.5 to 500 nm. Since the height of the second set of irregularities is on the nano-order, if vacuum void connections occur, the joint strength of the metal terminals decreases, and gaps are more likely to form due to thermal expansion or vibration, which can reduce the effectiveness of preventing leaks of water, oil, etc.

[0008] The metal terminal described in Patent Document 2 has V-grooves formed at two spaced locations along the length of the joint, extending around the entire circumference in the width direction. When the temperature of the resin molded product rises, the portion of the resin member that contacts the metal terminal expands relative to the metal terminal due to the difference in linear thermal expansion coefficients between the two. As a result, there is a risk of gaps forming between the resin member and the metal terminal in the width and thickness directions. The resin member also expands in the length direction of the metal terminal, so the resin member comes into contact with a portion of the V-grooves. However, the contact area becomes smaller than before expansion. Moreover, since there are only two V-grooves, the total contact length (total contact area) with the resin member is small, which presents the problem of reduced sealing effect during thermal expansion. Note that the manufacturing method of the metal terminal described in Patent Document 2 is not disclosed.

[0009] Therefore, the present invention aims to provide a metal terminal that can enhance the sealing effect between a resin member and a metal terminal when the metal terminal is insert-molded with a resin member, and a method for manufacturing a metal terminal that can reduce the complexity of the metal terminal manufacturing apparatus and reduce manufacturing costs. [Means for solving the problem]

[0010] [1] The present invention relates to a method for manufacturing a metal terminal, which is a flat metal terminal covered with a resin member and having both ends in the longitudinal direction protruding from the resin member, and comprises a groove forming step in which a plurality of fine grooves are formed at the joint between the metal terminal and the resin member, and the cross-sectional shape of the plurality of grooves is rectangular, and the groove forming step comprises a side groove forming step in which the plurality of grooves are formed on both sides in the width direction of the metal terminal, and a front and back groove forming step in which the plurality of grooves are formed on both the front and back surfaces in the thickness direction of the metal terminal, and the side groove forming step skips one of the plurality of grooves and forms two grooves at a time. The surface groove forming process includes a first side die-casting step of forming right side grooves and left side grooves at intervals, and a second side die-casting step of further forming the right side grooves and left side grooves in the raised portions between adjacent right side grooves and between adjacent left side grooves formed in the first side die-casting step, wherein the surface groove forming step includes a first surface surface die-casting step of forming surface grooves and back grooves at 2-pitch intervals, skipping one of the plurality of grooves, and a second surface surface die-casting step of further forming the surface grooves and back grooves in the raised portions between adjacent surface grooves and between adjacent back grooves formed in the first surface surface die-casting step.

[0011] Here, the stamping process refers to the process of partially compressing a metal material with a press die punch to form a recess (groove) of the desired shape. Furthermore, multiple fine grooves refer to grooves with a pitch between grooves (i.e., pitch between rows) of approximately 0.1 mm to 0.4 mm, a groove opening width of approximately 0.02 mm to 0.2 mm, and a depth of approximately 0.02 mm to 0.2 mm. The shape of the grooves will be explained in detail in the embodiment.

[0012] [2] In the method for manufacturing metal terminals of the present invention, it is preferable that the second side stamping step involves inserting a stamping punch into the right side groove and the left side groove formed in the first side stamping step, thereby forming the right side groove and the left side groove on the protruding portion formed in the first side stamping step, and the second front and back stamping step involves inserting a stamping punch into the front groove and the back groove formed in the first front and back stamping step, thereby forming the front groove and the back groove on the protruding portion formed in the first front and back stamping step.

[0013] [3] In the method for manufacturing metal terminals of the present invention, it is preferable that after the second front and back die-stamping step, the method further includes an oblique die-stamping step in which a bulge that occurs at the intersection of the front groove and the back groove and protrudes from the right side groove and the left side groove is pressed obliquely into the inside of the right side groove and the left side groove from the vertical direction.

[0014] [4] In the method for manufacturing metal terminals of the present invention, it is preferable to further include a bulge crushing die-stamping step after the oblique die-stamping step, in which the bulge is crushed into the plane of the groove bottom of the right side groove and the plane of the groove bottom of the left side groove.

[0015] [5] In the method for manufacturing a metal terminal of the present invention, it is preferable to further include a bulge removal step after the side groove forming step and the front and back groove forming step, which removes bulges that occur at the intersection of the grooves formed on both sides in the width direction and the grooves formed on both the front and back surfaces, and that protrude from the grooves.

[0016] [6] In the method for manufacturing a metal terminal of the present invention, it is preferable to further include a finishing side stamping step and a finishing front and back stamping step for correcting the shape of the multiple grooves after the multiple grooves have been formed by the side groove forming step and the front and back groove forming step.

[0017] [7] In the method for manufacturing a metal terminal of the present invention, it is preferable that the metal terminal is manufactured by a progressive press device in the following order: a metal terminal outer shape cutting step in which the outer shape of the joint portion of the metal terminal is formed on a long metal material, a groove forming step, and a metal terminal punching step in which the metal terminal is removed from the metal material.

[0018] [8] The present invention relates to a method for manufacturing a metal terminal, wherein the metal terminal is covered with a resin member and both ends in the longitudinal direction protrude from the resin member, and comprises a groove forming step of forming a plurality of fine grooves continuous around the entire circumference in the width direction of the metal terminal at the joint between the metal terminal and the resin member, wherein the cross-sectional shape of the plurality of grooves is rectangular, and the groove forming step comprises a side groove forming step of forming the plurality of grooves on both sides in the width direction of the metal terminal, and a front and back groove forming step of forming the plurality of grooves on both the front and back surfaces in the thickness direction of the metal terminal. The invention provides a method for forming a groove, wherein the side groove forming step includes a side groove punching step to punch out both sides of the metal terminal in the width direction in the thickness direction to form a right side groove and a left side groove, and the front and back groove forming step includes a first front and back die-cutting step to form a front groove and a back groove at a 2-pitch interval, skipping one of the plurality of grooves, and a second front and back die-cutting step to further form the front groove and the back groove in the raised ridges between adjacent front grooves and between adjacent back grooves formed in the first front and back die-cutting step.

[0019] [9] In the method for manufacturing metal terminals of the present invention, it is preferable that the second front and back die-stamping step involves inserting a die-stamping punch into the front groove and back groove formed in the first front and back die-stamping step, while forming the front groove and back groove on the raised portion formed in the first front and back die-stamping step.

[0020]

[10] In the method for manufacturing metal terminals of the present invention, after the second front and back surface stamping step, It is preferable to further include an oblique punching step of generating a bulge at the intersection of the right side groove and the left side groove formed on both side surfaces in the width direction and the front surface groove and the back surface groove formed on both the front and back surfaces, and pushing the bulge protruding from the right side groove and the left side groove into the inside of the right side groove and the left side groove in an oblique direction.

[0021]

[11] In the method for manufacturing a metal terminal of the present invention, after the oblique punching step, it is preferable to further include a bulge crushing punching step of crushing the bulge in the plane of the groove bottom of the right side groove and in the plane of the groove bottom of the left side groove.

[0022]

[12] In the method for manufacturing a metal terminal of the present invention, after the second front and back surface punching step, it is preferable to further include a bulge removing step of removing the bulge generated at the intersection of the right side groove and the left side groove formed on both side surfaces in the width direction and the front surface groove and the back surface groove formed on both the front and back surfaces, and protruding from the right side groove and the left side groove.

[0023]

[13] In the method for manufacturing a metal terminal of the present invention, after removing the bulge, it is preferable to further include a finishing front and back surface punching step of correcting at least the groove shapes of the front surface groove and the back surface groove.

[0024]

[14] In the method for manufacturing a metal terminal of the present invention, the metal terminal is preferably manufactured by a progressive press device in the order of a metal terminal outer shape punching step of forming the outer shape of the joint portion of the metal terminal on a long metal material, the groove forming step, and a metal terminal punching step of punching out the metal terminal from the metal material.

[0025]

[15] The metal terminal of the present invention is manufactured by the method for manufacturing a metal terminal according to any one of [1] or [8] above, partially coated with the resin member, and both ends in the length direction protruding from the resin member, and having the plurality of fine grooves continuous over the entire circumference in the width direction of the metal terminal at the joint portion with the resin member.

[0026]

[16] In the metal terminal of the present invention, among the plurality of grooves, the width of the groove opening is 0.02 mm to 0.2 mm, the groove depth is 0.02 mm to 0.2 mm, and within the range where the cross-sectional shape of the groove can maintain a quadrangular shape, the groove pitch is 0.1 mm to 0.4 mm, and the groove has a taper angle that narrows from the groove opening toward the groove bottom, and the taper angle is preferably 5 degrees to 30 degrees.

Effect of the Invention

[0027] The present invention relates to a manufacturing method for forming a plurality of fine grooves continuous over the entire circumference in the width direction at the joint portion between the metal terminal and the resin member. Among the plurality of grooves, the grooves on both side surfaces in the width direction are formed in the side groove forming process, and the grooves on both front and back surfaces are formed in the front and back surface groove forming process.

[0028] Each groove forming process forms a plurality of grooves by a stamping process. The stamping process is performed by a press die including a punch and a press device as is well known. Here, in the case of fine grooves where the groove pitch (pitch between grooves) is, for example, 0.1 mm to 0.4 mm, when forming the grooves, there is a risk that the ridge portion (corresponding to the wall between the grooves) between adjacent grooves will be drawn in and a predetermined groove shape cannot be formed.

[0029] As a manufacturing method for the metal terminal, first, for the side groove forming process, one of the plurality of grooves is skipped in the first side stamping process to form grooves at a 2-pitch interval. By doing so, the groove pitch becomes twice as large, and the width of the ridge portion between adjacent grooves becomes wider. Therefore, it is possible to suppress the ridge portion from being drawn in during groove formation, and thus a groove with a predetermined shape can be formed. In the second side stamping process, since grooves have already been formed at a 2-pitch interval in the first side stamping process, the width of the ridge portion between substantially adjacent grooves is large. Therefore, it is possible to suppress the ridge portion from being drawn in during groove formation, and it becomes possible to form a groove with a predetermined shape. The front and back surface groove forming process is the same.

[0030] This manufacturing method allows for the formation of multiple grooves in the metal terminal without deformation, and enables the uniform filling of the resin component into these grooves. This increases the bonding strength (adhesion strength) between the resin component and the metal terminal, preventing leaks of water, oil, etc., from the joint. Furthermore, even if the resin component and metal terminal expand due to thermal expansion caused by rising ambient temperatures, the rectangular cross-sectional shape of each groove maintains adhesion between the resin component and the metal terminal in the thickness, width, and length directions, thus maintaining the sealing effect.

[0031] Furthermore, the groove formation process involves creating grooves in a side groove stamping process and a front / back surface stamping process. As mentioned above, the stamping process is a press process using a die and a press device. Therefore, compared to the manufacturing method described in Patent Document 1 above, which forms irregularities on metal terminals by irradiation with a laser beam, this process reduces the complexity of the metal terminal manufacturing equipment and significantly shortens the manufacturing cycle time, thus reducing manufacturing costs.

[0032] While it is possible to replace the groove formation process with a stamping process, stamping is a sealing process, which requires high pressure even for fine groove formation. This presents the challenge of needing a special press with a small stroke and high rigidity. [Brief explanation of the drawing]

[0033] [Figure 1] This is a cross-sectional view showing the structure of the resin molded body 1. [Figure 2] This is a perspective view showing an example of the configuration of a groove 20 formed in a metal terminal 10. [Figure 3] This shows an example of the shape of the surface groove 23, a cross-sectional view taken along the AA cutting line in Figure 2. [Figure 4] This is a process flow chart showing a method for manufacturing a metal terminal 10 according to the first embodiment. [Figure 5] This figure shows the first side-drilling process (step S2) for forming the right-side groove 21 and left-side groove 22 of the metal terminal 10. [Figure 6] This figure shows the second side-molding process (step S3) for forming the right-side groove 21 and left-side groove 22 of the metal terminal 10 according to the first embodiment. [Figure 7] This figure shows the first front and back die-cutting process (step S4) for forming the front groove 23 and back groove 24 of the metal terminal 10 according to the first embodiment. [Figure 8] This figure shows the second front and back die-cutting process (step S5) for forming the front groove 23 and back groove 24 of the metal terminal 10 according to the first embodiment. [Figure 9] This is a cross-sectional view of the metal terminal 10 after the second front and back groove stamping process (step S5) according to the first embodiment, cut along the CC cutting line in Figure 2. [Figure 10] This is a cross-sectional view showing the oblique die-cutting process (step S6) according to the first embodiment. [Figure 11] This is a cross-sectional view showing the expansion and crushing die-pressing process (step S7) according to the first embodiment. [Figure 12] This is a process flow chart showing a method for manufacturing a metal terminal 10 according to a modified example of the first embodiment. [Figure 13] This is a cross-sectional view showing a bulge removal process (step S26) according to a modified example of the first embodiment. [Figure 14] This is a process flow diagram showing a method for manufacturing a metal terminal 10 according to a second embodiment. [Figure 15] This is a cross-sectional view showing the side groove removal process (step S32) according to the second embodiment. [Modes for carrying out the invention]

[0034] The manufacturing method of the metal terminal 10 according to an embodiment of the present invention, and the configuration of the metal terminal 10 formed by this manufacturing method, will be described below with reference to Figures 1 to 15. Note that the embodiments described below do not limit the invention as defined in the claims. Furthermore, not all of the elements and their combinations described in each embodiment are necessarily essential to the solution of the present invention.

[0035] (Composition of resin molded body 1) Figure 1 is a cross-sectional view showing the structure of the resin molded body 1. The resin molded body 1 is formed by integrally molding a metal terminal 10, which is made of a flat plate, with a resin member 2 (this is called insert molding). The metal terminal 10 has both ends in the longitudinal direction protruding from the resin member 2. The area where the metal terminal 10 joins with the resin member 2 is called the joint 3. Note that Figure 1 is a schematic diagram showing one example of the structure of the resin molded body 1, and the shapes of the resin member 2 and the metal terminal 10 are not limited to this. The material of the metal terminal 10 can be copper, brass, or an iron alloy, but can be freely selected depending on the function to be used. The material of the resin member 2 is a high heat-resistant thermoplastic resin such as PPS resin or PPA resin.

[0036] The metal terminal 10 has multiple grooves 20 formed in an annular pattern that extend around the entire circumference in the width direction relative to the length direction, at least within the range of the joint 3 (see Figure 2). The inside of the grooves 20 is filled with a resin member 2 to prevent water, oil, etc. from leaking from the joint 3. For example, if the upper side of the resin member 2 shown in Figure 1 is the substrate placement area and the lower side of the resin member 2 is the liquid containment area for water, oil, etc., the joint 3 has the function of preventing oil from passing through the joint 3 from the liquid containment area into the substrate placement area.

[0037] (Configuration of metal terminal 10) Figure 2 is a perspective view showing an example of the configuration of grooves 20 formed in a metal terminal 10. Multiple grooves 20 are formed in the metal terminal 10, extending continuously around the entire circumference in the width direction within the range of the joint 3. In this example, the metal terminal 10 is a plate member with a rectangular cross-sectional shape when cut in the width direction. However, the metal terminal 10 may also be a columnar member. In Figure 2, the surfaces of the metal terminal 10 are represented as the front surface 11 and back surface 12, the right side surface 13 and the left side surface 14. Furthermore, in order to distinguish each groove formed in the metal terminal 10, the grooves 20 formed on the right side surface 13 are collectively referred to as right side grooves 21, the grooves 20 formed on the left side surface 14 are collectively referred to as left side grooves 22, the grooves 20 formed on the front surface 11 are collectively referred to as front grooves 23, and the grooves 20 formed on the back surface 12 are collectively referred to as back surface grooves 24. The groove 20 consists of multiple grooves, with the right side groove 21, left side groove 22, surface groove 23, and back groove 24 having the same cross-sectional shape and arranged in a continuous ring.

[0038] The grooves 20 are formed continuously around the entire circumference of both the front and back surfaces and both left and right sides of the metal terminal 10, with multiple grooves 20 arranged at intervals along the length of the metal terminal 10. The number of grooves 20 can be appropriately determined depending on the length of the joint 3 (thickness of the resin member 2) and the size and pitch of the grooves 20 that can be formed. The area sandwiched between adjacent grooves 20 is collectively called the raised ridge portion 30 and corresponds to the wall that demarcates the groove 20. The configuration of the grooves 20 and raised ridge portions 30 corresponding to each surface will be explained with reference to the figures from Figure 3 onward.

[0039] Figure 3 shows an example of the shape of the surface groove 23, and is a cross-sectional view taken when cut along the AA cutting line in Figure 2. Since the cross-sectional shape of each groove in this embodiment is the same, the surface groove 23 will be described as a representative example. In the example shown in Figure 3, the cross-sectional shape of the surface groove 23 is a rectangle with a groove opening width H of 0.02 mm to 0.2 mm and a groove depth D of 0.02 mm to 0.2 mm. The surface groove 23 is inclined with a taper angle θ that narrows from the groove opening 25 side to the groove bottom 26 side. The taper angle θ is formed according to the shape of each die punch (see Figures 5 to 11) described later, and is set to 5 to 30 degrees. The size and shape of each groove can be appropriately determined in consideration of the length of the joint 3 (see Figure 1) (thickness of the resin member 2), provided that there is a sealing effect. However, the size of the right side groove 21 and left side groove 22 and the surface groove 23 and back groove 24 do not necessarily have to be the same.

[0040] For example, when the metal terminal 10 is used as a conductor, the groove depth D is set to a minimum cross-sectional area that allows a predetermined power to be conducted and ensures that the electrical resistance is less than or equal to a predetermined value. The groove bottom 26 is not limited to a flat surface; it may also have a semi-circular shape with the central part in the groove width direction being deeper. Next, the manufacturing method of the metal terminal 10 will be described.

[0041] (First Embodiment) The metal terminal 10 has multiple fine grooves 20 formed in a groove-forming process that are continuous around the entire circumference in the width direction at the joint 3 with the resin member 2. The groove-forming process includes a side groove-forming process that forms a right side groove 21 and a left side groove 22 on both sides (right side 13 and left side 14) in the width direction of the metal terminal 10. The groove-forming process further includes a process that forms a surface groove 23 and a back groove 24 on both the front and back surfaces (front surface 11 and back surface 12) in the thickness direction of the metal terminal 10. The above-mentioned die-forming process will now be explained in accordance with the process flow diagram shown in Figure 4.

[0042] Figure 4 is a process flow diagram showing the manufacturing method of the metal terminal 10 according to the first embodiment. The process will be explained with reference to Figures 5 to 11 in accordance with the process flow diagram shown in Figure 4. The metal terminal 10 is manufactured in a continuous process using a progressive press from a long, flat metal material (not shown). First, the outer shape of the metal terminal 10 is formed by a metal terminal outer shape punching process (step S1). Although not shown, in this process, the outer shape is punched out in an area that includes at least the joint portion 3 (see Figure 1). At least a part of the metal terminal 10 is connected to the metal material. The groove 20 is not formed in this process.

[0043] Figure 5 shows the first side stamping process (step S2) for forming the right side groove 21 and left side groove 22 of the metal terminal 10 according to the first embodiment. Figure 5(a) is a cross-sectional view taken along the BB cutting line in Figure 5(b). Figure 5(b) is a plan view of the metal terminal 10 as seen from the surface 11 side. The thick arrows shown in Figures 5(a) and 5(b) represent the operation of the right side stamping punch 40 and the left side stamping punch 41 in the first side stamping process (step S2). As shown in Figures 5(a) and (b), the right side stamping punch 40 and the left side stamping punch 41 move simultaneously toward the right side 13 and left side 14 of the metal terminal 10, respectively, to perform the stamping process. As shown in Figure 5(a), the right side stamping punch 40 and the left side stamping punch 41 protrude from the surface 11 and back surface 12 of the metal terminal 10. The stamping process refers to a processing step in which a metal material is partially compressed with a press die to form a groove 20 of the desired shape.

[0044] The first side-punching process (step S2) punches both sides of the metal terminal 10 in the width direction, and therefore employs a well-known cam slide mechanism (not shown) in press die structures. Although not shown, this cam slide mechanism consists of a cam driver and a cam slider. A pair of left and right cam drivers move perpendicular to the surface 11, and a pair of upper and lower cam sliders move horizontally. Each of the left and right cam sliders corresponds to the right side punching punch 40 and the left side punching punch 41. Therefore, the metal material is provided with holes in the metal terminal outer shape punching process (step S1) that allow for the placement of the cam slide mechanism on both sides of the joint 3 in the width direction.

[0045] As shown in Figure 5(b), in the first side-stamping process (step S2), the right side groove 21 and the left side groove 22 are formed at intervals of 2 pitches relative to the groove pitch P (see Figure 3) of the groove 20 of the finished metal terminal 10. The first side-stamping process (step S2) will be explained with reference to Figure 6, which shows the second side-stamping process (step S3). As shown in Figure 6, the right side grooves 21 of the finished product are arranged as 21a, 21b, 21c, 21d, 21e, ... from the left side of the figure at intervals of 1 pitch. On the other hand, the left side grooves 22 of the finished product are arranged as 22a, 22b, 22c, 22d, 22e, ... from the left side of the figure at intervals of 1 pitch. The right side grooves 21 and the left side grooves 22 are positioned symmetrically with respect to the center line Q1 in the width direction of the metal terminal 10.

[0046] Returning to Figure 5(b), the first side die-cutting process (step S2) will be explained. In the first side die-cutting process (step S2), the right side groove 21 is formed from the left side of the figure as right side grooves 21a, 21c, 21e, ... skipping right side grooves 21b and 21d. Similarly, the left side groove 22 is formed from the left side of the figure as left side grooves 22a, 22c, 22e, ... skipping right side grooves 21b and 21d. In other words, the right side grooves 21 and the left side grooves 22 are formed every other groove, or every two pitches, relative to the finished form. As shown in Figure 5(b), a protruding ridge 31a is formed between the right side groove 21a and the right side groove 21c on the metal terminal 10, and a protruding ridge 31b is formed between the right side groove 21c and the right side groove 21e. The protruding sections 31a and 31b have a width obtained by subtracting the width H of the groove opening 25 from twice the groove pitch P (see Figure 3). Similarly, on the left side surface 14, a protruding section 32a is formed between the left side grooves 22a and 22c, and a protruding section 32b is formed between the left side grooves 22c and 22e.

[0047] After the first side-die stamping process (step S2), the metal material is transported to the next stage of the progressive press machine, and the process moves on to the second side-die stamping process (step S3).

[0048] Figure 6 shows the second side-facing process (step S3) for forming the right-side groove 21 and left-side groove 22 of the metal terminal 10 according to the first embodiment. Figure 6 is a plan view of the metal terminal 10 as seen from the surface 11 side. The second side-facing process (step S3) is a process in which the entirety of the right-side groove 21 and left-side groove 22 is formed at intervals of 1 pitch of the groove pitch P. The thick arrows shown in Figure 6 represent the operation of the right-side punch 44 and the left-side punch 45. The right-side punch 44 and the left-side punch 45 move simultaneously in the right-side 13 and left-side 14 directions relative to the surface 11 of the metal terminal 10 to perform the facing process. The second side-facing process (step S3) is performed by driving the right-side punch 44 and the left-side punch 45 by a cam slide mechanism, similar to the first side-facing process (step S2). The right-side punch 44 and the left-side punch 45 protrude from the front surface 11 and back surface 12 of the metal terminal 10 (see Figure 5(a)).

[0049] As shown in Figure 6, the second side-punching process (step S3) forms the right side grooves 21b, 21d, ... and the left side grooves 22b, 22d, ... that were not formed in the first side-punching process (step S2) described above. The second side-punching process (step S3) further forms the right side grooves 21b, 21d, ... in each of the protruding sections 31a, 31b, ... that were formed in the first side-punching process (step S2). The second side-punching process (step S3) also further forms the left side grooves 22b, 22d, ... in each of the protruding sections 32a, 32b, ... At this time, the right side-punching punch 44 and the left side-punching punch 45 have a shape that allows them to be inserted into the right side grooves 21a, 21c, 21e, ... and 22a, 22c, 22e, ... that were formed in the first side-punching process (step S2).

[0050] However, in the second side molding process (step S3), it is also possible to form grooves every two pitches, shifted by one pitch relative to the first side molding process (step S2). In other words, the second side molding process (step S3) may be a process that forms only the right side grooves 21b, 21d, ... or only the left side grooves 22b, 22d, ... that were not formed in the first side molding process (step S2). In such a method, if the right side groove 21b is formed on the protruding section 31a, protruding sections 35a, 35b are formed on both sides of the right side groove 21b, and protruding sections 35c, 35d are formed on both sides of the right side groove 21d. If the left side groove 22b is formed on the protruding section 32a, protruding sections 36a, 36b are formed on both sides of the left side groove 22b, and if the left side groove 22d is formed on the protruding section 32b, protruding sections 36c, 36d are formed on both sides of the left side groove 22d. Let's explain this in more detail using the raised ridge 31a as an example.

[0051] An attempt is made to form a right-side groove 21b in the protruding portion 31a. However, since the right-side grooves 21a and 21c have already been formed, the horizontal component of the pressing force from the right-side punching punch 44 may cause the protruding portion 35a to deform toward the right-side groove 21a side, and the protruding portion 35b to deform toward the right-side groove 21c side. Therefore, in the second side punching step (step S3), deformation of each groove can be prevented by punching all the grooves at once, including the already formed right-side grooves 21a, 21c, 21e, ... and left-side grooves 22a, 22c, 22d, ...

[0052] Figure 7 shows the first front and back die-punching process (step S4) for forming the surface groove 23 and back groove 24 of the metal terminal 10 according to the first embodiment. Figure 7(a) is a cross-sectional view of the metal terminal 10 cut along the BB cutting line in Figure 7(b). Figure 7(b) is a side view of the metal terminal 10 as seen from the left side 14. The thick arrows shown in Figures 7(a) and 7(b) represent the operation of the front die-punching punch 42 and the back die-punching punch 43 in the first front and back die-punching process (step S4). As shown in Figures 7(a) and 7(b), the front die-punching punch 42 and the back die-punching punch 43 move simultaneously in a direction perpendicular to the surface 11 of the metal terminal 10 to perform the die-punching process. As shown in Figure 7(a), the front die-punching punch 42 and the back die-punching punch 43 protrude from the right side 13 and the left side 14 of the metal terminal 10. The front die-punching punch 42 and the back die-punching punch 43 correspond to the punches of a press die. The reverse-side punch 43 corresponds to the die of a well-known press mold.

[0053] As shown in Figure 7(b), in the first front and back die-cutting process (step S4), the surface grooves 23 and back grooves 24 are formed at intervals of 2 pitches relative to the groove pitch P (see Figure 3) of the grooves 20 of the finished metal terminal 10. The first front and back die-cutting process (step S4) will be explained with reference to Figure 8, which shows the second front and back die-cutting process (step S5). As shown in Figure 8, the surface grooves 23 of the finished product are arranged as surface grooves 23a, 23b, 23c, 23d, 23e, ... from the left side of the figure at intervals of 1 pitch. On the other hand, the back grooves 24 are arranged as back grooves 24a, 24b, 24c, 24d, 24e, ... from the left side of the figure at intervals of 1 pitch. The surface grooves 23 and back grooves 24 are positioned symmetrically with respect to the center line Q2 (see Figure 8) in the thickness direction of the metal terminal 10.

[0054] Returning to Figure 7(b), the first front and back die-cutting process (step S4) will be explained. In the first front and back die-cutting process (step S4), the surface grooves 23 are formed from the left side of the figure as surface grooves 23a, 23c, 23e, ... skipping surface grooves 23b, 23d, ... The back grooves 24 are formed from the left side of the figure as back grooves 24a, 24c, 24e, ... skipping back grooves 24b, 24d, ... In other words, the surface grooves 23 and back grooves 24 are formed every other groove, or every two pitches, for the multiple grooves 20. As shown in Figure 7(b), a raised ridge 33a is formed between surface grooves 23a and 23c on the metal terminal 10, and a raised ridge 33b is formed between surface grooves 23c and 23e. The width of the raised ridges 33a and 33b is twice the groove pitch P minus the width H of the groove opening 25 (see Figure 3). Similarly, on the back surface 12, a raised ridge 34a is formed between the back surface groove 24a and the back surface groove 24c, and a raised ridge 34b is formed between the back surface groove 24c and the back surface groove 24e.

[0055] The surface grooves 23a, 23c, 23e, ... and the back grooves 24a, 24c, 24e, ... are each continuous with the right side grooves 21a, 21c, 21e, ... and the left side grooves 22a, 22c, 22e, ...

[0056] After the first front and back die stamping process (step S4), the metal material is transported to the next stage of the progressive press machine, and the process moves on to the second front and back die stamping process (step S5).

[0057] Figure 8 shows the second front and back die-punching process (step S5) for forming the front grooves 23 and back grooves 24 of the metal terminal 10 according to the first embodiment. Figure 8 is a side view of the metal terminal 10 as seen from the right side 13 side shown in Figure 6. The second front and back die-punching process (step S5) is a process in which all of the front grooves 23 and back grooves 24 are formed at intervals of 1 pitch of the groove pitch P. The thick arrows shown in Figure 8 represent the operation of the front die-punching punch 46 and back die-punching punch 47, which move simultaneously in a direction perpendicular to the surface 11 of the metal terminal 10 to perform the die-punching process. The front die-punching punch 46 and back die-punching punch 47 protrude from the right side 13 and left side 14 of the metal terminal 10 (see Figure 6).

[0058] As shown in Figure 8, the second front and back die-punching process (step S5) forms surface grooves 23b, 23d, ... and back grooves 24b, 24d, ... that were not formed in the first front and back die-punching process (step S3) described above. The second front and back die-punching process (step S5) further forms surface grooves 23b, 23d, ... in each of the protruding sections 33a, 33b, ... formed in the first front and back die-punching process (step S3), and further forms back grooves 24b, 24d in each of the protruding sections 34a, 34b, ... At this time, the front die-punching punch 46 and the back die-punching punch 47 are configured to be insertable into the surface grooves 23a, 23c, 23e, ... and back grooves 24a, 24c, 24e, ... formed in the first front and back die-punching process (step S3), respectively.

[0059] However, in the second front and back die-cutting process (step S5), it is also possible to form grooves every two pitches, shifted by one pitch relative to the first front and back die-cutting process (step S3). In other words, the second front and back die-cutting process (step S5) may be a process that forms only the surface grooves 23b, 23d, ... that were not formed in the first front and back die-cutting process (step S3), or only the back grooves 24b, 24d, ... In such a method, if the surface groove 23b is formed on the protruding part 33a, the protruding parts 37a, 37b are formed on both sides of the surface groove 23b, and the protruding parts 37c, 37d are formed on both sides of the surface groove 23d. If the back groove 24b is formed on the protruding part 34a, the protruding parts 38a, 38b are formed on both sides of the back groove 24b, and if the back groove 24d is formed on the protruding part 34b, the protruding parts 38c, 38d are formed on both sides of the back groove 24d. The convex portion 33a will be used as an example to explain in detail.

[0060] An attempt is made to form a surface groove 23b on the raised ridge portion 33a. However, since surface grooves 23a and 23c have already been formed, the horizontal component of the pressing force from the surface punching punch 46 may cause the raised ridge portion 37a to deform toward the surface groove 23a side and the raised ridge portion 37b to deform toward the surface groove 23c side. Therefore, in the second front and back surface punching process (step S5), deformation of each groove can be prevented by punching all the grooves at once, including the already formed right side grooves 21a, 21c, 31e, ... and left side grooves 22a, 22c, 22d, ...

[0061] Incidentally, the first side-facing die-cutting process (step S2) and the first front-back die-cutting process (step S4) form grooves 20 at intervals of two pitches among the multiple grooves 20. It is also possible to skip the first side-facing die-cutting process (step S2) and the first front-back die-cutting process (step S4) and perform the second side-facing die-cutting process (step S3) and the second front-back die-cutting process (step S5). The challenges of forming each groove in a single process will be explained using the second side-facing die-cutting process (step S3) as a representative example with reference to Figure 6.

[0062] In the second side die-punching process (step S3), the fine right side grooves 21a, 21b, 21c, ... are formed all at once. As previously described, each groove has a fine structure, with a groove pitch P of 0.1 mm to 0.4 mm and a groove opening width H of 0.02 mm to 0.2 mm. Therefore, when attempting to form all of the right side grooves 21 at once, even using a comb-shaped right side die-punching punch 44 corresponding to the shape of each groove, the raised ridges 35a, 35b, 35c, 35d, ... and the raised ridges 36a, 36b, 36c, 36d, ... are pulled in and become lower. In Figure 6, this phenomenon is schematically shown by the dotted line T. Although not shown, the same phenomenon occurs in the surface grooves 23 and back grooves 24.

[0063] When this phenomenon occurs, the predetermined groove shape cannot be formed. Therefore, by making the first side die-casting process (step S2) and the first front / back die-casting process (step S4) groove formation every two pitches, it is possible to prevent this phenomenon.

[0064] The second side die-cutting process (step S3) and the second front and back die-cutting process (step S5) form all of the multiple grooves 20. After the second front and back die-cutting process (step S5), bulges 52a to 52d (see Figure 9) may occur within the right side groove 21 and left side groove 22 at the intersection of the right side groove 21 and left side groove 22 and the front surface groove 23 and back surface groove 24. This situation will be explained with reference to Figure 9.

[0065] Figure 9 is a cross-sectional view of the metal terminal 10 after the second front and back groove stamping process (step S5) according to the first embodiment, cut along the CC cutting line in Figure 2. Figure 9 shows the various parts of the metal terminal 10 collectively (see Figure 1). A bulge 52a occurs at the intersection 51a of the groove bottom 26 of the surface groove 23 and the groove bottom 28 of the right side groove 21. A bulge 52b occurs at the intersection 51b of the groove bottom 28 of the right side groove 21 and the groove bottom 27 of the back groove 24. A bulge 52c occurs at the intersection 51c of the groove bottom 27 of the back groove 24 and the groove bottom 29 of the left side groove 22. And a bulge 52d occurs at the intersection 51d of the groove bottom 29 of the left side groove 22 and the groove bottom 26 of the surface groove 23. Note that Figure 9 exaggerates each bulge more than it actually is.

[0066] The grooves 20 of the metal terminal 10 are formed in a second side stamping process (step S3) and a second front / back stamping process (step S5). In a step prior to the second front / back stamping process (step S5), the metal terminal 10 already has a right side groove 21 and a left side groove 22 formed on it. Therefore, when the groove-forming portion of the metal terminal 10 is compressed by the second front / back stamping process (step S5), excess material bulges out 52a to 52d from the already formed and released right side groove 21 and left side groove 22, and is pushed out and protrudes. At that time, the bulges 52a to 52d may protrude from the right side 13 and left side 14.

[0067] Such bulges 52a to 52d can prevent the resin member 2 from filling into the groove 20 during insert molding, or even if it does fill, the bonding strength may deteriorate. Therefore, after the second front and back surface molding process (step S5), an oblique molding process (step S6) and a bulge-depressing molding process (step S7) are provided to flatten these bulges 52a to 52d from above and below.

[0068] Figure 10 is a cross-sectional view showing the oblique stamping process (step S6) according to the first embodiment. Figure 10, like Figure 9, shows the various parts of the metal terminal 10 collectively. The oblique stamping process (step S6) is a process in which the bulges 52a to 52d are crushed by oblique stamping punches 55 and 56 so as to bend them inward toward the groove bottoms 28 and 29. The oblique stamping punch 55 has a stamping portion 55a that enters the surface groove 23 formed on the metal terminal 10 and the right side groove 21 and left side groove 22 from an oblique upward angle. Each stamping portion 55a is equipped with an inclined portion 55b. The inclined portions 55b are arranged to sandwich the metal terminal 10 from the surface 11 side toward the intersection portions 51a and 51d.

[0069] The diagonal punch 56 has a back groove 24 formed in the metal terminal 10, and a punching portion 56a that enters the right side groove 21 and left side groove 22 from diagonally below. Each punching portion 56a has a slanted portion 56b. The slanted portions 56b are positioned to sandwich the metal terminal 10 from the back side 12 towards the intersections 51b and 51c.

[0070] The angled punch 55 operates perpendicular to the back surface 12 of the metal terminal 10 from the front surface 11 side, and the angled punch 56 operates perpendicular to the back surface 12 from the back surface 12 side (indicated by thick arrows). As a result, the angled portion 55b of the angled punch 55 crushes the bulge 52a so as to bend it inward toward the right side groove 21 from the front surface 11 side. Similarly, the angled portion 55b crushes the bulge 52d so as to bend it inward toward the left side groove 22 from the front surface 11 side. The angled portion 56b of the angled punch 56 crushes the bulge 52b so as to bend it inward toward the right side groove 21 from the back surface 12 side. Similarly, the angled portion 56b crushes the bulge 52c so as to bend it inward toward the left side groove 22 from the back surface 12 side. In Figure 10, the deformation of the bulges 52a to 52d is shown by thin arrows. However, the diagonal molding process (step S6) cannot completely flatten the bulges 51a to 51d.

[0071] After the oblique die stamping process (step S6), the metal terminal 10 is transported to the next stage of the progressive press machine and the process moves on to the bulge-crush die stamping process (step S7).

[0072] Figure 11 is a cross-sectional view showing the bulge-crushing die-punching process (step S7) according to the first embodiment. The bulge-crushing die-punching punches 57 and 58 used in the bulge-crushing die-punching process (step S7) can be the same configuration as the right-side die-punching punch 44 and left-side die-punching punch 45 used in the second side die-punching process (step S3) (see Figure 6). On the right side 13, the bulge-crushing die-punching punch 57 crushes the bulges 52a and 52b, which are in the process of being crushed, to a position where they are embedded in the groove bottom 28 by the oblique die-punching process (step S6). On the left side 14, the bulge-crushing die-punching punch 58 crushes the bulges 52c and 52d, which are in the process of being crushed, to a position where they are embedded in the groove bottom 29 by the oblique die-punching process (step S6).

[0073] Note that the bulges 52a and 52b do not need to be completely embedded in the groove bottom 28; it is sufficient that at least the bulges 52a and 52b are in close contact with the groove bottom 28. The same applies to the bulges 52c and 52d. In Figure 11, the movement of the bulge crushing punch 57 and 58 is shown with thick arrows, and the deformation of the bulges 52a to 52d is shown with thin solid arrows. The thick solid lines represent the bulges 52a to 52d after the bulge crushing punching process (step S7).

[0074] From the first side stamping process (step S2) to the expansion and crushing stamping process (step S7), multiple continuous grooves 20 are formed on the metal terminal 10 along its entire circumference in the width direction. However, there is a risk that the grooves 20 may deform during any of the processes or during transport due to their fineness.

[0075] After the expansion and crushing die stamping process (step S7), the metal terminal 10 is transported to the next stage of the progressive press machine, and the process moves on to the finishing side die stamping process (step S8) and the finishing front and back die stamping process (step S9).

[0076] The finishing side die-punching process (step S8) is a repetition of the same process as the second side die-punching process (step S3) described above. This will be explained with reference to Figure 6. In the finishing side die-punching process (step S8), die-punching is performed using the right side die-punching punch 44 and the left side die-punching punch 45 after the bulge-flattening die-punching process (step S7). This corrects the groove shape of the right side groove 21 and the left side groove 22, and the deformation of the convex portion 30 (see Figures 2 and 3).

[0077] Furthermore, the finishing front and back die-stamping process (step S9) is a repetition of the same process as the second front and back die-stamping process (step S5) described above. This will be explained with reference to Figure 8. In the finishing front and back die-stamping process (step S9), the front die-stamping punch 46 and back die-stamping punch 47 are used to stamp the front grooves 23 and back grooves 24 that have already been formed in the second front and back die-stamping process (step S5). This corrects the deformation of the groove shape of the front grooves 23 and back grooves 24 and the raised ridges 30 (see Figures 2 and 3).

[0078] As shown in Figure 3, the groove 20 has a shape in which the groove opening 25 side is wider than the groove bottom 26 due to the taper angle θ. Therefore, each punch used for the oblique punching process (step S6), the bulge-crushing punching process (step S7), the finishing side punching process (step S8), and the finishing front and back punching process (step S9) can perform the above processes without interfering with the already formed protrusions 30.

[0079] Next, after the finishing front and back die stamping process (step S9), the metal terminal 10 is transported to the next stage of the progressive press machine and the process moves to the metal terminal punching process (step S10).

[0080] As previously described, in the metal terminal outer shape punching process (step S1), the outer shape including at least the joint portion 3 (see Figure 1) is punched out, so that the metal terminal 10 is partially connected to the metal material. That is, the metal terminal 10 is connected to the metal material by a so-called tie bar. Then, after forming multiple grooves 20 through each die punching process, the metal terminal 10 is formed by punching it out of the metal material.

[0081] The first embodiment relates to a method for manufacturing a metal terminal 10 having a plurality of fine grooves 20 that are continuous around the entire circumference in the width direction at the joint 3 between the metal terminal 10 and the resin member 2.

[0082] Multiple grooves 20 are formed by a die-casting process, including a right side groove 21, a left side groove 22, a surface groove 23, and a back groove 24. The right side groove 21 and left side groove 22 are first formed by a first side groove die-casting process (step S2), where multiple grooves 20 are formed at 2-pitch intervals. Then, in the positions not formed in the first side groove die-casting process (step S2), the right side groove 21 and left side groove 22 are formed at 1-pitch intervals by a second side groove die-casting process (step S4). On the other hand, the surface grooves 23 and back groove 24 are first formed by a first front / back die-casting process (step S3), where multiple grooves 20 are formed at 2-pitch intervals. Then, in the positions not formed in the first front / back die-casting process (step S3), the surface grooves 23 and back groove 24 are formed at 1-pitch intervals by a second front / back die-casting process (step S5).

[0083] Incidentally, it is conceivable to omit the first side groove die-cutting process (step S2) and the first front / back die-cutting process (step S4). However, as previously described, each groove has a fine structure, with a groove pitch P of 0.1 mm to 0.4 mm and a groove opening width H of 0.02 mm to 0.2 mm. Therefore, if the right side groove 21, left side groove 22, surface groove 23, and back groove 24 are formed all at once, the protruding ridges 30 between adjacent grooves will be pulled into the grooves and become lower, preventing the formation of grooves 20 of the predetermined shape. Thus, by forming grooves every two pitches using the first side groove-cutting process (step S2) and the first front / back die-cutting process (step S4), it is possible to prevent shrinkage.

[0084] According to the manufacturing method of the metal terminal 10 in the first embodiment, the metal terminal 10 can have multiple grooves 20 formed without deformation, and the resin member 2 can be uniformly filled into the multiple grooves 20. Therefore, it is possible to increase the bonding strength (adhesion strength) between the resin member 2 and the metal terminal 10, prevent leakage of water, oil, etc. from the joint 3, and enhance the sealing effect. In addition, the cross-sectional shape of each groove is square. Therefore, even if the resin member 2 and the metal terminal 10 expand due to thermal expansion as the temperature of the operating environment rises, the adhesion between the resin member 2 and the metal terminal 10 can be maintained in any direction of the thickness, width, and length of the metal terminal 10. Therefore, it is possible to maintain the sealing effect even in high-temperature environments.

[0085] Furthermore, the grooves 20 are formed by a side groove stamping process and a front / back stamping process. As mentioned above, the stamping process is a press process using a press die and a press device. Therefore, compared to the manufacturing method described in Patent Document 1 above, which forms irregularities on the metal terminal 10 by irradiation with a laser beam, this method reduces the complexity of the metal terminal manufacturing equipment and significantly shortens the manufacturing cycle time, thereby reducing manufacturing costs.

[0086] In the first embodiment, the process involves performing a second side-punching process (step S3) following a first side-punching process (step S2). However, the process may also involve performing a first front / back-punching process (step S4) after the first side-punching process (step S2). Alternatively, the process may involve performing the first front / back-punching process (step S4), the second front / back-punching process (step S5), followed by the first side-punching process (step S2) and the second side-punching process (step S3). In the process of each of the punching processes from step S2 to step S5 described above, when the second side-punching process (step S3) is the final process, the bulges 52a to 52d protrude towards the front groove 23 and back groove 24 sides. Therefore, the bulge crushing punches 57 and 58 are configured to punch from the front 11 side and the back 12 side.

[0087] Furthermore, the second side die-cutting process (step S3) forms right side grooves 21b, 21d, ... and left side grooves 22b, 22d, ..., including the right side grooves 21a, 21c, 21e, ... and left side grooves 22a, 22c, 22e formed in the first side die-cutting process (step S2). The second front and back die-cutting process (step S5) forms surface grooves 23c, 23d, ... and back grooves 24b, 24d, ..., including the surface grooves 23a, 23c, 23e, ... and back grooves 24a, 24c, 24e, ..., including the surface grooves 23a, 23c, 23e, ... and back grooves 24a, 24c, 24e, ..., formed in the first front and back die-cutting process.

[0088] Referring to the second side die-punching process (step S3), when the right side groove 21b is formed on the protruding portion 31a, protruding portions 35a and 35b are formed on both sides of the right side groove 21b, and protruding portions 35c and 35d are formed on both sides of the right side groove 21d. Now, let's try to form the right side groove 21b on the protruding portion 31a. In this case, since the right side grooves 21a and 21c have already been formed, the horizontal component of the pressing force from the right side die-punching punch 44 may cause the protruding portion 35a to deform towards the right side groove 21a side, and the protruding portion 35b to deform towards the right side groove 21c side.

[0089] In the second side stamping process (step S3), all grooves, including the already formed right side grooves 21a, 21c, 31e, ... and left side grooves 22a, 22c, 22d, ..., are stamped together, thereby preventing deformation of each protrusion, i.e., each groove. The second front and back stamping process (step S5) can be explained similarly, so its explanation is omitted here.

[0090] The manufacturing method for the metal terminal 10 according to the first embodiment includes a diagonal die-stamping step (step S6) after the second front and back die-stamping step (step S5). The second front and back die-stamping step (step S5) generates bulges 52a to 52d at the intersections 51a to 51d of the right side groove 21 and the left side groove 22 with the surface groove 23 (groove bottom 26) and the back groove 24 (groove bottom 27). The diagonal die-stamping step (step S6) crushes these generated bulges 52a to 52d by bending them inward into the right side groove 21 and the left side groove 22. This makes it easier for the resin member 2 to fill into the groove 20.

[0091] However, in the oblique die-stamping process (step S6), gaps may form between the bent bulges 52a to 52d and the groove bottom 28 of the right side groove 21 and the groove bottom 29 of the left side groove 22. The resin member 2 does not fill these gaps, and the bonding strength (adhesion) between the metal terminal 10 and the resin member 2 cannot be obtained. Therefore, the bulge crushing die-stamping process (step S7) is used to embed the bulges 52a to 52d into the groove bottoms 28 and 29. In this way, it becomes possible to fill the groove 20 with the resin member 2. Note that the bulges 52a to 52d do not necessarily have to be embedded into the groove bottoms 28 and 29; it is sufficient if the bulges 52a to 52d are in close contact with the groove bottoms 28 and 29.

[0092] From the first side stamping process (step S2) to the expansion and crushing stamping process (step S7), a groove 20 of a predetermined shape is formed on the metal terminal 10, extending continuously around its entire circumference in the width direction. However, there is a risk that the groove 20 may deform during any of the processes or during transport due to its fineness. Therefore, the manufacturing method according to the first embodiment includes a finishing side stamping process (step S8) and a finishing front and back stamping process (step S9). The finishing side stamping process (step S8) repeats the same process as the second side stamping process (step S4) after the expansion and crushing stamping process. On the other hand, the finishing front and back stamping process (step S9) repeats the same process as the second front and back stamping process (step S5) after the finishing side stamping process (step S8). The finishing side stamping process (step S8) and the finishing front and back stamping process (step S9) make it possible to correct the deformation of the groove 20.

[0093] Furthermore, if no deformation of the groove 20 is detected after the bulging and crushing die-pressing process (step S7), the finishing side die-pressing process (step S8) and the finishing front and back die-pressing process (step S9) can be omitted.

[0094] In the manufacturing method of the metal terminal 10 according to the first embodiment, the metal terminal 10 is manufactured by a progressive press device in the following order: a metal terminal outer shape punching step (step S1) in which the outer shape of the joint portion 3 is formed, groove forming steps (steps S2 to S9), and a metal terminal punching step (step S10) in which the metal terminal 10 is punched out from the metal material. This method of manufacturing the metal terminal 10 is press work using a press die and a progressive press device. Therefore, compared to the manufacturing method described in Patent Document 1 above, in which irregularities are formed on the metal terminal 10 by irradiation with a laser beam, the complexity of the manufacturing equipment for the metal terminal 10 can be reduced, and the manufacturing cycle time can be significantly shortened, thereby reducing manufacturing costs.

[0095] (Modified version of the first embodiment) The manufacturing method for the metal terminal 10 according to the first embodiment allows for some modification of the manufacturing process. This will be explained as a modification of the first embodiment. The first embodiment described above includes an oblique die-stamping process (step S6) and a bulge-crushing die-stamping process (step S7). The modification differs in that it includes a bulge-removal process (step S26, see Figure 12) in which the bulges 52a to 52d are punched out and removed.

[0096] Figure 12 is a process flow chart showing a method for manufacturing a metal terminal 10 according to a modified example of the first embodiment. It will be explained in comparison with the process flow chart of the first embodiment shown in Figure 4. In the modified example, the metal terminal outer shape punching process (step S21) to the second front and back surface stamping process (step S25) is the same as the metal terminal outer shape punching process (step S2) to the second front and back surface stamping process (step S5) in the first embodiment shown in Figure 4. Also, the finishing side stamping process (step S27) to the metal terminal punching process (step S29) in the modified example is the same as the finishing side stamping process (step S8) to the metal terminal punching process (step S9) in the first embodiment shown in Figure 4. In other words, the only difference in the modified example is that the bulge punching-out process (step S26) is added in place of the oblique stamping process (step S6) and the bulge crushing stamping process (step S7) in the first embodiment. The bulge punching-out process (step S26) will be explained with reference to Figure 13.

[0097] Figure 13 is a cross-sectional view showing the bulge removal process (step S26) according to a modified example of the first embodiment. After the second front and back die stamping process (step S25), the metal material is transported to the next stage of the progressive press and proceeds to the bulge removal process (step S26). As previously described, bulges 52a to 52d protrude from the metal terminal 10 as a result of the first front and back die stamping process (step S23) and the second front and back die stamping process (step S25). The situation in which the bulges 52a to 52d protrude is shown in Figure 9. In the modified example of the first embodiment, the bulges 52a to 52d are removed by a bulge removal punch 59. The bulge removal punch 59 moves along the groove bottom 28 of the right side groove 21 and the groove bottom 29 of the left side groove 22, from the surface groove 23 to the back groove 24, forming groove bottoms 28 and 29 from which the bulges 52a to 52d have been removed.

[0098] In the modified version of the first embodiment, the metal terminal 10 has its bulges 52a to 52d removed by a bulge-removing punch 59. As a result, the oblique die-punching process (step S6) and the bulge-crushing die-punching process (step S7) in the first embodiment can be omitted, making it possible to shorten the line length of the progressive press.

[0099] Note that the surface grooves 23 and back grooves 24 are formed before the bulging and punching process (step S26). Therefore, it is conceivable that the back grooves 24 and the raised ridges 38a, 38b, 38c, ... may be deformed by the pressing force applied during the bulging and punching process (step S26). However, since the bulges 52a to 52d are very small compared to the thickness of the metal terminal 10, the back grooves 24 and the raised ridges 38a, 38b, 38c, ... will not be crushed or deformed by the pressing force applied during punching (see Figure 8).

[0100] (Second Embodiment) Next, a second embodiment of the method for manufacturing the metal terminal 10 will be described. As shown in Figure 4, the method for manufacturing the metal terminal 10 according to the first embodiment described above forms the right side groove 21 and the left side groove 22 by a first side stamping step (step S2) and a second side stamping step (step S3). In contrast, the method for manufacturing the metal terminal 10 according to the second embodiment is characterized by forming the right side groove 21 and the left side groove 22 by punching them out. This will be explained with reference to Figures 14 and 15.

[0101] Figure 14 is a process flow diagram showing the manufacturing method of the metal terminal 10 according to the second embodiment. The differences from the first embodiment will be explained in detail while comparing it with the process flow diagram of the first embodiment shown in Figure 4. The manufacturing method of the metal terminal 10 according to the second embodiment is performed in the order of metal terminal outer shape cutting process (step S31) and side groove punching process (step S32). The metal terminal outer shape cutting process (step S31) is the same process as the metal terminal outer shape cutting process (step S1) of the first embodiment. However, the metal terminal outer shape cutting process (step S31) makes it possible to simultaneously form the right side grooves 21a, 21b, 21c, 21d, 21e, ... and the left side grooves 22a, 22b, 22c, 22d, 22e, ... Therefore, the side groove punching process (step S32) can be omitted.

[0102] After the metal terminal outer shape punching process (step S31), the metal material is transported to the next stage of the progressive press machine and proceeds to the side groove punching process (step S32).

[0103] Figure 15 is a cross-sectional view showing the side groove punching process (step S32) according to the second embodiment. In the side groove punching process (step S32), the right side groove 21 and the left side groove 22 are formed by the side groove punching punch 60. The operation of the side groove punching punch 60 is shown by a thick arrow. The right side groove 21 and the left side groove 22 are formed in the same shape as in the second side die punching process (step S4) in the first embodiment (see Figure 6). The side groove punching punch 60 penetrates from the front surface 11 to the back surface 12 of the metal terminal 10. In other words, the metal terminal 10 is simultaneously formed with right side grooves 21a, 21b, 21c, 21d, 21e, ... and left side grooves 22a, 22b, 22c, 22d, 22e, ... at one-pitch intervals, as shown in Figure 6.

[0104] After the side groove punching process (step S32), the metal material is transported to the next stage of the progressive press and proceeds to the first front and back die stamping process (step S33). The first front and back die stamping process (step S33) is the same as the first front and back die stamping process (step S4) of the first embodiment, in which surface grooves 23a, 23c, 23e, ... and back grooves 24a, 24c, 24e, ... are formed at 2-pitch intervals (see Figure 5(b)). After the first front and back die stamping process (step S33), the metal material is transported to the next stage of the progressive press and proceeds to the second front and back die stamping process (step S34). The second front and back die stamping process (step S34) is the same as the second front and back die stamping process (step S5) of the first embodiment.

[0105] Following the second front and back die-stamping process (step S34), the process proceeds in the following order: diagonal die-stamping (step S35), bulge-crushing die-stamping (step S36), finishing side die-stamping (step S37), finishing front and back die-stamping (step S38), and metal terminal punching (step S39). These processes are the same as the diagonal die-stamping process (step S6, see Figure 10), bulge-crushing die-stamping (step S7, see Figure 11), finishing side die-stamping (step S8, see Figure 6), finishing front and back die-stamping (step S9, see Figure 8), and metal terminal punching (step S39, not shown) following the second front and back die-stamping process (step S5) in the first embodiment, so detailed explanations and illustrations are omitted.

[0106] In the second embodiment, the manufacturing method for the metal terminal 10 involves forming the right side groove 21 and the left side groove 22 in a side groove punching step (step S32). In the first embodiment, the right side groove 21 and the left side groove 22 are formed in the first side die punching step (step S2) and the second side die punching step (step S4). As previously described, the right side die punches 40, 44 and the left side die punches 41, 45 used in the first side die punching step (step S2) and the second side die punching step (step S4) employ a well-known cam slide mechanism (not shown) in press die structures. The cam slide mechanism consists of a cam driver that moves vertically and a cam slider that moves horizontally, with the cam sliders corresponding to the right side die punches 40, 44 and the left side die punches 41, 45. Therefore, the metal material requires a large space to provide holes on both sides in the width direction of the joint 3 that allow for the placement of the cam slide mechanism.

[0107] In the second embodiment, the right side groove 21 and the left side groove 22 are formed by a side groove punching punch 60 of a general press die structure. The side groove punching punch 60 moves perpendicular to the surface 11 of the metal terminal 10. Therefore, there is only space within the movable range of the vertically moving side groove punching punch 60. Consequently, if the length of the metal material is the same, it becomes possible to manufacture a large number of metal terminals 10, thereby reducing the cost of the metal material (raw material cost), i.e., the cost of the metal terminals 10.

[0108] In the first embodiment, the bulges 52a to 52d (see Figure 9) are caused by the first side stamping process (step S2) to the second front and back stamping process (step S5), which cause protrusions on the surface groove 23 side and the back groove 24 side. However, in the second embodiment, no bulges occur due to the first side groove punching process (step S2) and the second side groove stamping process (step S3). In other words, the bulges 52a to 52d (see Figure 9) are only those that occur in the first front and back stamping process (step S33) and the second front and back stamping process (step S35). Therefore, the bulges 52a to 52d may be smaller. If the bulges 52a to 52d are within a range that does not affect the sealing effect, the oblique stamping process (step S35) and the bulge crushing stamping process (step S36) can be omitted. In this way, the metal terminal manufacturing apparatus can be further simplified, and the manufacturing cost of the metal terminal 10 can be reduced.

[0109] Furthermore, if no deformation is detected in the groove 20 after the completion of the bulging and crushing die-stamping process (step S36) or the second front and back die-stamping process (step S34), the finishing side die-stamping process (step S37) and the finishing front and back die-stamping process (step S38) can be omitted.

[0110] Furthermore, modifications of the first embodiment can also be applied to the second embodiment. Although not shown in the figures, in order to remove the bulges 52a to 52d, a bulge removal process (step S26, see Figures 12 and 13) can be provided instead of the oblique die-casting process (step S35) and the bulge crushing die-casting process (step S36) shown in Figure 14.

[0111] The metal terminal 10 has grooves 20 formed by the manufacturing methods according to the first and second embodiments. The grooves 20 consist of multiple continuous annular grooves in the width direction of the metal terminal 10. The grooves 20 are fine grooves with a groove opening width H of 0.02 mm to 0.2 mm, a groove depth D of 0.02 to 0.2 mm, and a groove pitch P of 0.1 mm to 0.4 mm, within a range that allows the cross-sectional shape to maintain a rectangular shape. By having multiple such grooves 20 and filling the resin member 2 into multiple grooves 20, it is possible to enhance the sealing effect between the resin member and the metal terminal 10.

[0112] Referring to Figures 3 and 4, the surface groove 23 has a taper angle θ that narrows from the groove opening 25 towards the groove bottom 26. The taper angle θ is between 5 and 30 degrees. The surface groove 23 is formed by repeating die-punching processes such as the first side die-punching process (step S2), the first front and back die-punching process (step S4), the second side die-punching process (step S3), the second front and back die-punching process (step S5), the oblique die-punching process (step S6), the bulge-crushing die-punching process (step S7), the finishing side die-punching process (step S8), and the finishing front and back die-punching process (step S9). Because a taper angle θ is provided, the punches in the subsequent processes do not interfere with the protrusions 30 formed in the previous process, making it possible to form a surface groove 23 of a predetermined shape. The back groove 24, the right side groove 21, and the left side groove 22 can be explained in the same way as the surface groove 23. [Explanation of symbols]

[0113] 2...Resin component, 3...Joint, 10...Metal terminal, 11...Surface, 12...Back, 13...Right side, 14...Left side, 20...Groove (general term), 21...Right side groove (general term), 21a~21e...Right side groove, 22...Left side groove (general term), 22a~22e...Left side groove, 23...Surface groove (general term), 23a~23e...Surface groove, 24...Back groove (general term), 24a~24e...Back groove, 25...Groove opening, 26~29...Groove bottom, 30...Protruding part (general term), 31a,31b,32a,32b,33a,33b,34a,34b,35a~35d,36a~ 36d, 37a~37d, 38a~38d...Convex section, 40, 44...Right side die punch, 41, 45...Left side die punch, 42, 46...Surface die punch, 43, 47...Back side die punch, 51a~51d...Intersection, 52a~52d...Bulge, 55, 56...Diagonal die punch, 55a, 56a...Die punch section, 55b, 56b...Slanted section, 57, 58...Bulge crush die punch, 59...Bulge punch, 60...Side groove punch, D...Groove depth, H...Width of groove opening, P...Groove pitch, θ...Taper angle

Claims

1. A method for manufacturing a metal terminal that is covered with a resin member and has both ends in the longitudinal direction protruding from the resin member, The process includes forming a groove at the joint between the metal terminal and the resin member, in which multiple grooves are formed continuously around the entire circumference in the width direction of the metal terminal. The cross-sectional shape of the aforementioned multiple grooves is rectangular. The groove forming step comprises a side groove forming step of forming the plurality of grooves on both sides of the metal terminal in the width direction, and a front and back groove forming step of forming the plurality of grooves on both the front and back surfaces in the thickness direction of the metal terminal. The side groove forming step includes a first side die-casting step of forming right side grooves and left side grooves at two-pitch intervals, skipping one of the plurality of grooves, and a second side die-casting step of further forming right side grooves and left side grooves in the protruding portions between adjacent right side grooves and between adjacent left side grooves formed in the first side die-casting step. The surface groove forming step includes a first surface die-cutting step of forming surface grooves and surface grooves at two-pitch intervals, skipping one of the multiple grooves, and a second surface die-cutting step of further forming surface grooves and surface grooves in the raised portions between adjacent surface grooves and between adjacent surface grooves formed in the first surface die-cutting step. A method for manufacturing metal terminals, characterized by the following:

2. In the method for manufacturing a metal terminal according to claim 1, The second side die-punching step involves inserting a die-punching punch into the right side groove and the left side groove formed in the first side die-punching step, while forming the right side groove and the left side groove on the protruding portion formed in the first side die-punching step. The second front and back die-stamping step involves inserting a die-stamping punch into the surface groove and the back groove formed in the first front and back die-stamping step, while forming the surface groove and the back groove on the raised portion formed in the first front and back die-stamping step. A method for manufacturing metal terminals, characterized by the following:

3. In the method for manufacturing a metal terminal according to claim 1, After the second front and back die-cutting process, The process further includes a diagonal stamping step in which a bulge that occurs at the intersection of the right side groove and the left side groove and the surface groove and protrudes from the right side groove and the left side groove is diagonally pressed into the inside of the right side groove and the left side groove. A method for manufacturing metal terminals, characterized by the following:

4. In the method for manufacturing a metal terminal according to claim 3, After the aforementioned diagonal die-cutting process, The process further includes a bulge-crushing die-pressing step in which the bulge is crushed into the plane of the groove bottom of the right side groove and the plane of the groove bottom of the left side groove. A method for manufacturing metal terminals, characterized by the following:

5. In the method for manufacturing a metal terminal according to claim 1, After the side groove forming step and the front and back groove forming step, The process further includes a bulge removal step for removing bulges that occur at the intersection of the right side groove and the left side groove with the surface groove and the back groove, and that protrude from the right side groove and the left side groove. A method for manufacturing metal terminals, characterized by the following:

6. In the method for manufacturing a metal terminal according to claim 1, After forming the multiple grooves by the side groove forming step and the front and back groove forming step, the method further includes a finishing side die-cutting step and a finishing front and back die-cutting step for correcting the shape of the multiple grooves. A method for manufacturing metal terminals, characterized by the following:

7. In the method for manufacturing a metal terminal according to claim 1, The aforementioned metal terminal is manufactured by a progressive press in the following order: a metal terminal outer shape cutting step to form the outer shape of the joint portion of the metal terminal on a long metal material, a groove forming step, and a metal terminal punching step to remove the metal terminal from the metal material. A method for manufacturing metal terminals, characterized by the following:

8. A method for manufacturing a metal terminal that is covered with a resin member and has both ends in the longitudinal direction protruding from the resin member, The process includes forming a groove at the joint between the metal terminal and the resin member, in which multiple fine grooves are formed continuously around the entire circumference in the width direction of the metal terminal. The cross-sectional shape of the aforementioned multiple grooves is rectangular. The groove forming step comprises a side groove forming step of forming the plurality of grooves on both sides of the metal terminal in the width direction, and a front and back groove forming step of forming the plurality of grooves on both the front and back surfaces in the thickness direction of the metal terminal. The side groove forming step includes a side groove punching step in which the sides of the metal terminal in the width direction are punched out in the thickness direction to form a right side groove and a left side groove, The surface groove forming step includes a first surface die-cutting step of forming surface grooves and surface grooves at two-pitch intervals, skipping one of the multiple grooves, and a second surface die-cutting step of further forming surface grooves and surface grooves in the raised portions between adjacent surface grooves and between adjacent surface grooves formed in the first surface die-cutting step. A method for manufacturing metal terminals, characterized by the following:

9. In the method for manufacturing a metal terminal according to claim 8, The second front and back die-stamping step involves inserting a die-stamping punch into the surface groove and the back groove formed in the first front and back die-stamping step, while forming the surface groove and the back groove on the raised portion formed in the first front and back die-stamping step. A method for manufacturing metal terminals, characterized by the following:

10. In the method for manufacturing a metal terminal according to claim 8, After the second front and back die-cutting process, The process further includes a diagonal stamping step in which a bulge that occurs at the intersection of the right side groove and the left side groove and the surface groove and protrudes from the right side groove and the left side groove is diagonally pressed into the inside of the right side groove and the left side groove. A method for manufacturing metal terminals, characterized by the following:

11. In the method for manufacturing a metal terminal according to claim 10, After the aforementioned diagonal die-cutting process, The process further includes a bulge-crushing die-pressing step in which the bulge is obliquely pressed into the plane of the groove bottom of the right side groove and the plane of the groove bottom of the left side groove. A method for manufacturing metal terminals, characterized by the following:

12. In the method for manufacturing a metal terminal according to claim 8, After the second front and back die-cutting process, The process further includes a bulge removal step for removing bulges that occur at the intersection of the right side groove and the left side groove with the surface groove and the back groove, and that protrude from the right side groove and the left side groove. A method for manufacturing metal terminals, characterized by the following:

13. In the method for manufacturing a metal terminal according to claim 12, The process further includes a finishing front and back die-cutting process to correct the groove shape of at least the surface grooves and the back grooves, after the aforementioned bulge removal process. A method for manufacturing metal terminals, characterized by the following:

14. In the method for manufacturing a metal terminal according to claim 8, The aforementioned metal terminal is manufactured by a progressive press in the following order: a metal terminal outer shape cutting step to form the outer shape of the joint portion of the metal terminal on a long metal material, a groove forming step, and a metal terminal punching step to remove the metal terminal from the metal material. A method for manufacturing metal terminals, characterized by the following:

15. Manufactured by the method for manufacturing metal terminals described in either claim 1 or claim 8, A portion of the metal terminal is covered with the resin member, and both ends in the longitudinal direction protrude from the resin member. The joint with the resin member has a plurality of fine grooves that are continuous around the entire circumference in the width direction of the metal terminal. A metal terminal characterized by the following features.

16. In the metal terminal according to claim 15, The aforementioned multiple grooves have a groove opening width of 0.02 mm to 0.2 mm, a groove depth of 0.02 mm to 0.2 mm, and a groove pitch of 0.1 mm to 0.4 mm, within a range that allows the cross-sectional shape of the grooves to maintain a rectangular shape. The groove has a taper angle that narrows from the groove opening towards the groove bottom, and the taper angle is 5 to 30 degrees. A metal terminal characterized by the following features.

Images