Method for applying sealing resin

Abstract

To make application of a sealing resin proper while suppressing reduction of productivity.SOLUTION: The method for applying a sealing resin includes: arranging a guide plate 50 with a penetration hole 51 below an application nozzle 20 when covering a conductor joint part A, formed by joining a core wire Wa exposed to a terminal of an electric wire W to a terminal 10 with a sealing resin 30; arranging a terminal 10 below the guide plate 50; and dropping the sealing resin 30 to discharge from the application nozzle 20, to the conductor joint part A of the terminal 10 through the penetration hole 51 of the guide plate 50.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for applying a sealing resin. [Background technology]

[0002] When a terminal and an electric wire conductor are made of dissimilar metals, there is a risk of electrochemical corrosion if moisture penetrates into the contact area between the dissimilar metals. For example, when a terminal is made of copper or copper alloy and the conductor (core wire) of an electric wire is made of aluminum or aluminum alloy, it is known that electrochemical corrosion may occur at the conductor joint where the conductor of the electric wire is joined to the terminal if moisture penetrates into the conductor joint.

[0003] Patent Document 1 describes a method for preventing electrolytic corrosion in which an exposed portion is formed at the end of an electric wire by removing a portion of the coating in the circumferential direction so that the core wire is exposed, and the end of the electric wire is connected to a terminal in a state where the terminal is in contact with the core wire exposed at this exposed portion. According to this method, since the coating of the electric wire remains around the exposed portion of the core wire, the adhesion between this coating and the terminal prevents moisture from penetrating the exposed core wire portion, thereby suppressing electrolytic corrosion.

[0004] However, with this method, depending on how the terminal is crimped onto the electric wire, the core wire may remain exposed to the outside, and therefore, there is a risk that electrolytic corrosion may not be effectively prevented.

[0005] Therefore, a conventional method has often been adopted in which a sealing resin is applied to the conductor joint of the terminal, and the exposed portion of the core wire is covered and concealed with the hardened sealing resin.

[0006] The method will be described with reference to FIGS. FIG. 4 is a top view of a terminal to which an end portion of an electric wire is joined. The terminal 10 has an electrical connection portion 11 at its front end for connecting to a mating terminal, and a conductor crimping portion 12 at its rear end for crimping and fixing an exposed portion of the core wire Wa at the end of the electric wire W. Also, behind the conductor crimping portion 12, a covering crimping portion 13 for crimping the covering Wb of the electric wire W is provided. Note that the core wire Wa is not specifically shown in FIG. 4.

[0007] Because the bottom plate 18 is continuous from the electrical connection portion 11 at the front end of the terminal 10 to the coating crimping portion 13 at the rearmost end, there is no risk of moisture intrusion from the bottom plate 18 side. However, because the portion above the bottom plate 18 is separated independently into the electrical connection portion 11, the conductor crimping portion 12, and the coating crimping portion 13, there is a possibility of moisture intrusion. Therefore, when the core wire Wa exposed by removing the coating Wb is crimped to the conductor crimping portion 12, the core wire Wa will be exposed in the portions before and after it.

[0008] Therefore, the application points of the sealing resin are determined so as to cover all the areas where the core wire Wa may be exposed. The positions and number of application points vary depending on the type and amount of resin to be dripped.

[0009] For example, in the space 14 between the conductor crimping portion 12 and the electrical connection portion 11, the upper side of the bottom plate 18 of the terminal 10 is open, so at least the tip portion of the core wire Wa crimped to the conductor crimping portion 12 is exposed. Therefore, a position A1 on the front side of the conductor crimping portion 12 is set as the application point. Also, in the space 15 between the conductor crimping portion 12 and the coating tightening portion 13, the upper side of the bottom plate 18 of the terminal 10 is open, so there is a possibility that the core wire Wa from which the coating Wb has been removed may be exposed to some extent. Therefore, a position A3 on the front side of the conductor crimping portion 12 is set as the application point.

[0010] In addition, the conductor crimping portion 12 has a structure in which the crimping pieces on both sides are rolled inward while being crimped to the core wire Wa, and is therefore a location where the core wire Wa is likely not to be exposed. However, if a gap is formed at the mating portion between the left and right crimping pieces of the conductor crimping portion 12, moisture may enter through that portion. For this reason, position A2 corresponding to the mating portion between the left and right crimping pieces of the conductor crimping portion 12 is also set as a coating point. The conductor crimping portion 12 and the portions before and after it that should be covered by coating the sealing resin at these multiple coating points A1, A2, and A3 are referred to as the "conductor joint portion A" in this specification.

[0011] Fig. 5 is an explanatory diagram of a coating method for coating a sealing resin using a coating device (dispenser). As shown in Fig. 5, in this coating method, the terminal 10 is held horizontally with the bottom plate 18 facing down and set below a coating nozzle 20 for the sealing resin. Then, liquid sealing resin 30 is dripped from the coating nozzle 20 of the coating device, and the conductor joint A is covered and concealed with sealing resin 31 that hardens over time, etc., to protect it from the intrusion of moisture.

[0012] FIG. 5 shows a state in which the sealing resin 31 has been properly applied. Fig. 5 shows a state in which the exposed core wire Wa is properly covered with the hardened sealing resin 31 without any gaps above the front side of the conductor crimping portion 12, i.e., the amount and position of application are normal. Fig. 6 is a cross-sectional view showing a state in which the required portions of the conductor joint portion A are completely covered with the hardened sealing resin 31. [Prior art documents] [Patent documents]

[0013] [Patent Document 1] JP 2010-61906 A Summary of the Invention [Problem to be solved by the invention]

[0014] However, in the above-mentioned application method, the amount and position of application of the sealing resin 30 may deviate from normal conditions. 7, if the application position is shifted and the amount of the sealing resin 30 applied is small at some places, the core wire Wa may not be covered with the hardened sealing resin 31, resulting in an exposed portion E of the core wire Wa. In this case, corrosion may occur at the exposed portion E.

[0015] 8, if a large amount of sealing resin 30 is applied, the resin may drip from the side of terminal 10, increasing the overall dimensions of terminal 10. This may make it difficult to insert terminal 10 into cavity 40 of the connector, or in the worst case, may make it impossible to insert terminal 10.

[0016] One possible solution to prevent this would be to match the shape of the nozzle outlet of the application nozzle 20 to the point coordinates of the application target. However, doing so would take time to set up and switch the application nozzle, which could reduce productivity.

[0017] The present invention has been made in consideration of the above-mentioned circumstances, and an object of the present invention is to provide a method for applying a sealing resin that enables optimization of the application of the sealing resin while suppressing a decrease in productivity. [Means for solving the problem]

[0018] In order to achieve the above object, the method for applying a sealing resin according to the present invention has the following features. A guide plate having a through hole is disposed below the application nozzle, a terminal having a conductor joint portion to which a conductor of an electric wire is joined, the terminal being disposed below the guide plate, the sealing resin discharged from the application nozzle being dropped onto the conductor joint portion through the through hole; the conductor joint portion is covered by hardening the dropped sealing resin; A method for applying sealing resin. Effect of the Invention

[0019] According to the present invention, it is possible to optimize the application of the sealing resin while suppressing a decrease in productivity.

[0020] The present invention has been briefly described above. Furthermore, the details of the present invention will be further clarified by reading the following description of the embodiment of the present invention (hereinafter, referred to as "embodiment") with reference to the accompanying drawings. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is a perspective view showing a state in which a method for applying a sealing resin according to one embodiment of the present invention is about to be carried out. [Diagram 2] FIG. 2 is a side view showing the state during the application method. [Diagram 3] FIG. 3 is a perspective view showing the state after the application method is completed. [Figure 4] FIG. 4 is a top view of the terminal showing the application points of the sealing resin to the electric wire joints. [Diagram 5] FIG. 5 is an explanatory diagram of a coating method for coating a sealing resin using a coating device (dispenser), and is a cross-sectional view showing a state in which the resin has been properly applied. [Figure 6] FIG. 6 is a cross-sectional side view of a terminal showing a case where the resin has been properly applied. [Figure 7] FIG. 7 is a cross-sectional view showing an example in which the resin has been applied improperly. [Figure 8] FIG. 8 is a cross-sectional view showing a case where the resin is applied improperly, resulting in an increase in outer dimensions and causing interference when inserted into a cavity of a connector. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Specific embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing a state in which a method for applying a sealing resin according to one embodiment of the present invention is about to be carried out, FIG. 2 is a side view showing the situation in the middle of carrying out the same application method, and FIG. 3 is a perspective view showing the state after the application method has been completed.

[0023] As shown in FIG. 1, the method of applying the sealing resin in this embodiment is based on the premise that the sealing resin 30 is dripped from an application nozzle 20 disposed above the conductor joint portion A onto a conductor joint portion A at which a core wire Wa (see FIG. 2) exposed at the end of an electric wire W is joined to a terminal 10.

[0024] 1 to 3, a guide plate 50 having a through hole 51 shaped to correspond to the conductor joint A of the terminal 10 is placed below the application nozzle 20, and the terminal 10 is placed below the guide plate 50. Then, the sealing resin 30 discharged from the application nozzle 20 is dripped onto the required portion of the conductor joint A of the terminal 10 through the through hole 51 of the guide plate 50. In this way, the sealing resin 30 is properly applied to the required portion of the conductor joint A, and at least the required portion of the conductor joint A is covered and concealed by the hardened sealing resin 31.

[0025] The through hole 51 of the guide plate 50 is provided in a shape corresponding to the conductor crimping portion 12 of the terminal 10 and the portions (conductor joint portions A) in front of and behind which the core wire (conductor) Wa is exposed.

[0026] In this way, by dropping the sealing resin 30 through the through hole 51 of the guide plate 50 to the required location of the conductor joint A of the terminal 10, if the relative positions of the terminal 10 and the guide plate 50 are determined, the application position and application amount can be appropriately controlled and managed even if there is some variation in the position of the application nozzle 20 or the application amount of the sealing resin 30. Therefore, as shown in FIG. 8, it is possible to prevent the sealing resin 30 from dripping onto the side of the terminal 10, which may adversely affect the insertability of the terminal 10 into the cavity 40 of the connector, or as shown in FIG. 7, it is possible to prevent the application position from shifting and the core wire (conductor) Wa from being exposed. In addition, even if the terminal 10 to be applied is changed, it can be handled by simply replacing the guide plate 50, so that the time required for changing the setup can be reduced.

[0027] The through hole 51 of the guide plate 50 may have different shapes on the upper and lower sides. For example, the upper side may be formed as a continuous wide opening to easily receive the sealing resin 30 dropped from the application nozzle 20, and the lower side may be formed to have small holes only at positions corresponding to the places where application is required (application points). Also, a through hole may be formed with a cross-sectional shape that gradually narrows from the opening on the upper side toward the lower side.

[0028] Here, the features of the sealing resin application method according to the embodiment of the present invention described above will be briefly summarized and listed in the following [1]-[2]. [1] A guide plate (50) having a through hole (51) is disposed below the application nozzle (20), A terminal (10) is disposed below the guide plate and has a conductor joint portion (A) to which a conductor (core wire Wa) of an electric wire (W) is joined. The sealing resin (30) discharged from the application nozzle is dropped onto the conductor joint portion through the through hole, the conductor joint portion is covered by hardening the dropped sealing resin; A method for applying sealing resin.

[0029] According to the sealing resin application method of the configuration [1] above, the sealing resin is dropped onto the conductor joint of the terminal through the through hole of the guide plate. Therefore, if the relative positions of the terminal and the guide plate are determined in advance, the application position and application amount can be properly controlled even if there is some variation in the position of the application nozzle or the amount of sealing resin applied. This prevents the sealing resin from dripping onto the side of the terminal, adversely affecting the insertion of the terminal into the cavity of the connector, or from being misaligned to expose the conductor. In addition, even if the terminal to be applied is changed, it can be handled by simply replacing the guide plate, reducing the time required to change the setup.

[0030] [2] The through hole has a shape corresponding to the conductor joint portion. A method for applying the sealing resin described in [1] above.

[0031] According to the method of applying sealing resin having the configuration [2] above, the sealing resin is dripped onto the conductor joint through a light-transmitting tube having a shape corresponding to the conductor joint, thereby making it possible to more appropriately control the variation in the position of the application nozzle and the variation in the amount of sealing resin applied. [Explanation of symbols]

[0032] 10 Terminals 11 Electrical connections 12 Conductor crimping section 13 Covering and tightening part 20 Application nozzle 30 Sealing resin 31 Hardened sealing resin 50 Guide Plate 51 Through hole A Conductor joint A1~A3 Application points W electric wire Wa Core wire (conductor) Wb coating

Claims

1. A guide plate having a through hole is disposed below the application nozzle, a terminal having a conductor joint portion to which a conductor of an electric wire is joined, the terminal being disposed below the guide plate, the sealing resin discharged from the application nozzle being dropped onto the conductor joint portion through the through hole; the conductor joint portion is covered by hardening the dropped sealing resin; A method for applying sealing resin.

2. The through hole has a shape corresponding to the conductor joint portion. A method for applying the sealing resin according to claim 1.

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