JP2002180258A - Grounding terminal block made of aluminum alloy and method of manufacturing for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a grounding terminal block made of an aluminum alloy which is capable of making a plating layer thinner, reducing the cost and improving the dimensional accuracy and is not inferior in all terms (quality), such as corrosion resistance and electric resistance value as compared to conventional products. SOLUTION: This terminal block 1 made of the aluminum alloy is constituted by forming a terminal hole 2 of an approximately L shape in side view for connecting of a lead wire 6 near the end on a long piece 1a side, plating the part near the end on the long piece 1a side including the terminal hole 2 and its periphery and applying an epoxy resin coating 4 on the periphery at the boundary between the plating layer 3 and the aluminum alloy base material. The plating layer 3 is formed of a three-layered structure consisting of a ground surface layer of electroless nickel and phosphorus, an intermediate plating layer of electrolytic copper and a finish plating layer of electroless nickel and phosphorus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum alloy ground terminal block mainly used for aluminum alloy railway vehicles and a method of manufacturing the same.

[0002]

2. Description of the Related Art A typical conventional terminal A of the above-mentioned ground terminal block.
As shown in FIG. 6, a terminal hole 51 for connecting a lead wire is provided near an end on one long side in a substantially L-shape when viewed from the side, and an end on one long side including the terminal hole 51 and its periphery is provided. The plating layer 52 and the aluminum alloy base material 5
3, an epoxy resin-based coating 54 is applied around the boundary. The plating layer 52 has a three-layer structure. The base plating layer and the finish plating layer are electrolytic nickel plating layers, and the intermediate plating layer is an electrolytic copper plating layer. The thickness of the base plating layer is 6 μm, the thickness of the intermediate plating layer is 30 μm, and the thickness of the finish plating layer is 6 μm.

[0003] The grounding terminal block has a short side attached to the floor of an aluminum alloy vehicle body by welding, and a T-shaped terminal is press-fitted into a terminal hole on the long side, and the end of the copper lead wire is connected to the head of the terminal. It is generally used in a state where it is wound around and fastened.

[0004]

The conventional product A described above has room for improvement from the following reasons, and development of a new product is required. That is, the plating portion 52 of the ground terminal block 50 is electrolytically plated in all three layers as described above, but the terminal hole 51 is provided near the end on one long side like the ground terminal block. Since there is an edge on the entire periphery of the ground terminal block 50 including the periphery of the terminal hole 51 and the periphery thereof, for example, the inner peripheral surface of the terminal hole 51 does not easily flow electricity and is hardly plated, and each edge portion easily flows electricity. Plating is difficult to be performed uniformly over the whole, for example, the plating thickness is increased. For this reason, it is necessary to make the thickness of the plating layer relatively large so as to cover so that pinholes cannot be formed.

[0005] Since the thickness of the plating layer is increased, the plating solution is increased, and since each plating layer is formed by electrolytic plating, a long time is required for the operation, the production cost is increased, and the dimensional accuracy is reduced.

As is well known, when electroless plating (chemical plating) is used, plating can be performed more uniformly than electrolytic plating. However, electroless nickel plating is difficult to be plated on an aluminum alloy base material, and electrolytic nickel plating is also used. Therefore, when the terminal for lead wire connection is fastened, the nickel plating layer may be cracked and peeled off.

The present invention has been made in view of the above points, and can reduce the thickness of the plating layer, reduce the cost and improve the dimensional accuracy.
An object of the present invention is to provide an aluminum alloy ground terminal block and a method for manufacturing the same, which are comparable in all aspects (quality) such as electric resistance.

[0008]

In order to achieve the above object, an aluminum alloy grounding terminal block according to the present invention is provided with a terminal for connecting a lead wire near an end on one long side having a substantially L shape in a side view. An aluminum alloy ground terminal block provided with a hole, plated near the end of the long side including the terminal hole and the periphery thereof, and applying an epoxy resin coating around a boundary between the plating layer and the aluminum alloy base material. Wherein the plating layer has a three-layer structure of a base plating layer of electroless nickel / phosphorus, an intermediate plating layer of electrolytic copper, and a finish plating layer of electroless nickel / phosphorus.

According to the aluminum alloy ground terminal block of the present invention having the above configuration, the base plating layer is made of an electroless nickel alloy.
Since it is made of phosphorous plating, it can be made thinner and more uniform than electrolytic nickel plating.
Phosphorus plating reduces the thickness compared to electrolytic nickel plating and enables uniform coating over the entire surface, preventing corrosion of the lower copper plating layer. Moreover, since the plating layer of nickel and phosphorus is very hard compared to the nickel plating layer,
Excellent corrosion resistance. On the other hand, when it becomes hard, it becomes brittle and cracks are easily formed, but since the intermediate plating layer is provided with a highly flexible copper plating layer, it acts as a so-called cushioning material and the terminals are used when connecting lead wires. Even if it is inserted into the terminal hole and tightened, cracks and the like do not easily enter. In addition, since the periphery of the boundary between the plating layer and the aluminum alloy substrate was covered with an epoxy resin-based coating film, current flowed to the ground terminal block when the terminal was attached to the terminal hole and the lead wire was connected. Sometimes, electrical corrosion that may be caused by a large potential difference between nickel and the aluminum alloy is prevented.

[0010] As described in claim 2, the thickness of the base plating layer can be 3 µm, the thickness of the intermediate plating layer can be 20 µm, and the thickness of the finish plating layer can be 5 µm. That is, the thickness can be reduced to 2/3 to 1/2 of the plating thickness of the conventional product in which the plating layers are all electrolytic plating layers.

With this configuration, the cost can be reduced as compared with the conventional product, and the dimensional accuracy of the ground terminal block can be greatly improved.

According to a third aspect of the present invention,
Except for the plating part near the end on the long side, including the terminal hole and its surroundings, of the aluminum alloy grounding terminal block material that is substantially L-shaped when viewed from the side and has holes for connecting lead wires near the end on the long side After masking with a tape or the like, the base material surface of the plating portion is subjected to alkali etching treatment, and then zinc / nickel substitution treatment is performed to form a zinc / nickel coating on the surface, and electroless nickel plating is applied as a base plating. After washing with water, apply electrolytic copper plating as intermediate plating and wash with water, then apply electroless nickel plating again as finish plating and wash with water, remove the masking tape etc. and dry, finish plating layer and substrate Is characterized in that an epoxy resin coating is applied around the boundary line.

According to the manufacturing method of the third aspect, the ground terminal block made of aluminum alloy has a high reactivity to chlorine, and is easily corroded when exposed to salt water or the like. Although it is necessary to eliminate it, a zinc / nickel coating is formed by previously performing a zinc / nickel replacement treatment on the aluminum alloy base material at the plating location. For this reason, the corrosion resistance of the coating itself is improved, and when immersing in a plating solution when performing electroless nickel / phosphorous plating as a base plating, the zinc / nickel film does not elute, and pinholes are less likely to occur, and nickel / nickel High adhesion between phosphorus plating layer and aluminum alloy substrate. Further, since the alkali etching treatment is performed before the zinc / nickel substitution treatment, the acidic zinc / nickel substitution liquid is neutralized.
In addition, since the base plating and finish plating are electroless nickel plating, even in places where electricity does not easily flow, such as the inner peripheral surface of the terminal hole, they are satisfactorily contacted by immersion in a plating bath to form a uniform nickel plating layer. Is done. Further, since phosphorus is contained in the reducing agent of the electroless plating, and the nickel-phosphorus alloy plating layer is formed, the hardness of the plating layer is 520Hv to 620Hv (measured by a micro Vickers hardness meter) and the hardness of the conventional product. Sa (230Hv ~ 300H
Compared with v), it is very hard, has excellent mechanical strength, and has excellent corrosion resistance and chemical resistance.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an aluminum alloy grounding terminal block according to the present invention will be described with reference to the drawings, and a manufacturing method thereof will be described in detail.

FIG. 1 is a front view and a side view showing an aluminum alloy ground terminal block according to this embodiment. FIG. 2 is a side view showing a use state in which a lead wire is connected to a terminal hole of the ground terminal block of FIG. 1 via a terminal. FIG. 3 is a flowchart showing a manufacturing process of the ground terminal block of FIG.

As shown in FIG. 1, the ground terminal block 1 is substantially L-shaped when viewed from the side, has a predetermined width (for example, 50 mm), a predetermined length (for example, 120 mm) and a thickness of several mm (for example, 4 mm).
mm) of a base material made of an aluminum alloy is bent at a substantially right angle so that the length of the long piece 1a side is almost three times the length of the short piece 1b side, and the center (width) near the end of the long piece 1a side (Direction) in which a circular terminal hole 2 is formed. In addition, a corner portion is chamfered 1c from one end on the long piece 1a side to the vicinity of the bent portion.

The inner peripheral surface of the terminal hole 2 on the long piece 1a side and the surface of the base material near the end with respect to the terminal hole 2 are formed in a plating part 3, and three plating layers are sequentially formed from the base material side. It is formed in a laminated state. Further, a coating 4 of an epoxy resin-based paint having a constant width is applied to the entire periphery around the boundary between the plating portion 3 and the base material exposing portion 3 ′. Plating part 3
Is an electroless nickel / phosphorous plating layer,
The intermediate plating layer is a copper electroplating layer, and the finish plating layer is a nickel / phosphorus electroless plating layer. In this example, the thickness of the base plating layer is 3 μm and the thickness of the intermediate plating layer is 20.
μm, and the thickness of the finished plating layer is 5 μm.

The ground terminal block 1 configured as described above is
For example, as shown in FIG. 2, a short piece 1b side is fixed to the bottom of a body 8 of an aluminum alloy vehicle by fillet welding, a T-shaped terminal 5 is provided in a terminal hole 2, and one end of a lead wire 6 made of a copper wire is provided at the head thereof. The body 8 is connected by winding and press-fitting, and a current is passed through the vehicle body 8, the vehicle body 8 is grounded, and as shown in FIG.
Used to connect with.

Next, a method of manufacturing the ground terminal block 1 according to the above embodiment will be described. In addition, the aluminum alloy base material is formed into a substantially L shape, the terminal hole 2 is formed, and the chamfer 1c is formed.
The conventional process A before machining mechanically, and the post process of coating with an epoxy resin paint after plating
Since it is common to (FIG. 6) and well known, the description is omitted. As shown in the flowchart of FIG. 3, 1) whether the substantially L-shaped base material is visually scratched or rusted;
Inspect for burrs.

2) The burrs on the substantially L-shaped substrate are removed by polishing with sandpaper or the like.

3) Unnecessary portions are masked with a tape while leaving the portions of the plating portions 3.

4) The substantially L-shaped base material is immersed in an alkali cleaner solution, and the base material surface of the plating portion 3 is alkali-etched. Then wash with water.

5) An approximately L-shaped substrate is immersed in a nitric acid solution to activate the surface of the substrate of the plating section 3 with acid. Then wash with water.

6) The substantially L-shaped base material is immersed in a zinc / nickel replacement liquid to replace the base material surface of the plating portion 3 with zinc / nickel (alloy). Then wash with water.

7) The operations 5) and 6) are repeated.

8) An approximately L-shaped substrate is immersed in a medium phosphorus (8 to 10% by weight) nickel plating solution, and electroless nickel plating is performed. Then wash with water.

9) The plating portion 3 of the substantially L-shaped substrate is immersed in a copper sulfate plating solution, and a current is applied to perform electrolytic copper plating. Then wash with water. 10) An approximately L-shaped substrate is immersed in a medium phosphorus (8 to 10% by weight) nickel plating solution, and electroless nickel plating is performed. Then wash with water. 11) Remove the masking tape from the substantially L-shaped substrate. 12) Dry the substantially L-shaped substrate. 13) Inspect the plated portion 3 of the substantially L-shaped substrate. 14) The periphery of the boundary between the plating portion 3 and the exposed portion of the base material is coated with an epoxy resin based coating at a constant width, and dried.

Through the series of steps described above, the ground terminal block 1 of this embodiment is completed. Here, the results of a comparison inspection of the completed ground terminal block 1 (also referred to as the product 1 of the present invention) with the conventional product A (FIG. 6) are shown.

Results of Hardness Measurement by Micro Vickers Hardness As shown in FIG. 4, the hardness of the plated portion 3 and the base material was measured at regular intervals in the width direction. The measured load at this time is 5
0 gf. The measurement results are as shown in Table 1 below,
The hardness (average) of the ground terminal block 1 of this example was 571, which was considerably higher than the hardness (average) 265 of the conventional product A.

[0030]

[Table 1] Electric resistance measurement result Only the ground terminal block 1 (parts) and the terminal hole 2 of the ground terminal block 1
The electrical resistance was measured by a tester (not shown) in a state where the lead wire 6 was connected to the terminal 5 by the terminal 5. The measurement was performed on the conventional product A in the same manner. The measurement results are as shown in Table 2 below, and there was almost no difference.

[0031]

[Table 2] Corrosion resistance test results After spraying a 5% aqueous sodium chloride solution (brine) on the ground terminal block 1 and the conventional product A for 100 hours, the two were visually compared.
No corrosion such as white rust from the aluminum alloy substrate was observed,
The corrosion resistance was good and there was no difference.

Although the embodiment of the ground terminal block 1 according to the present invention has been described above, products of various sizes can be manufactured, and the thicknesses of the base plating layer, the intermediate plating layer, and the finish plating layer can be varied. It is needless to say that the thickness of the intermediate plating layer can be reduced to about half of that of the conventional product A, and the thickness of the intermediate plating layer can be increased to about 30 μm, for example. Further, the electroless nickel plating is not limited to the medium phosphorus plating solution, and a high phosphorus plating solution containing about 13% by weight of phosphorus can be used. In this case, the hardness of the plating layer can be further improved.

Further, the shape of the ground terminal block 1 is not limited to the above-described substantially L-shape, and there are various shapes. For example, FIG. 5 is a front view and a side view showing a substantially Z-shaped ground terminal block 1 '. FIG. The ground terminal block 1 'of this example has a shape in which the end 1d on the short piece 1b side is further bent at a substantially right angle in a direction opposite to the long piece 1a side, and has a terminal hole 2 near the end on the long piece 1a side. The periphery thereof is composed of a plating portion 3 of three layers (electroless nickel / phosphorous plating / electrolytic copper plating / electroless nickel / phosphorous plating), and the plating portion 3 and the base material 3 ′
And an epoxy resin-based coating 4 is applied around the boundary between them and the basic structure and the manufacturing method thereof are the same as those of the first embodiment. Note that the results of the hardness measurement, the electric resistance measurement, and the corrosion resistance test are also the same as those in the first example.
It is exactly the same as the result of the example.

Furthermore, although the electroless plating takes only a few minutes, the electrolytic plating requires a long time of 10 to 20 hours, so that the manufacturing method of the present invention is shorter than the manufacturing time of the conventional product A. Thus, the manufacturing cost can be considerably reduced, and the quality can be reduced in all aspects as compared with the conventional product A.

[0035]

As is apparent from the above description,
The aluminum alloy ground terminal block and the method of manufacturing the same according to the present invention have the following excellent effects.

(1) The ground terminal block according to claim 1 can reduce the thickness of the plating layer to reduce the cost and improve the dimensional accuracy. In addition, all aspects (quality) such as corrosion resistance and electric resistance value as compared with the conventional product can be achieved. There is no inferiority. Further, the hardness of the plating layer is very hard as compared with the hardness of the conventional product, and is excellent in corrosion resistance, chemical resistance, and the like.

(2) The ground terminal block according to the second aspect can reduce the cost as compared with the conventional product, and can greatly improve the dimensional accuracy of the ground terminal block.

(3) In the manufacturing method according to the third aspect, since the corrosion resistance of the zinc / nickel coating itself is improved, the zinc / nickel coating is immersed in a plating solution when performing electroless nickel / phosphorus plating. Is not eluted and pinholes are hardly generated, and the adhesion between the nickel-phosphorus plating layer and the aluminum alloy base material is high. In addition, since the base plating and the finish plating are electroless nickel plating, even in places where electricity does not easily flow, such as the inner peripheral surface of the terminal hole, they are sufficiently contacted by immersion in the plating bath to form a uniform nickel plating layer. Therefore, the thickness of the plating layer can be reduced to about half that of the conventional product. Furthermore, phosphorus is contained in the reducing agent of the electroless plating, and since the nickel-phosphorus alloy plating layer is formed, the hardness of the plating layer can be hardened,
Since two of the three plating layers are made of electroless plating, the manufacturing time can be greatly reduced and the cost can be reduced.

[Brief description of the drawings]

1 shows an aluminum alloy ground terminal block according to an embodiment of the present invention, wherein FIG. 1 (a) is a front view and FIG. 1 (b) is a side view thereof.

FIG. 2 shows the ground terminal block 1 of FIG.
FIG. 2 (a) is a side view, and FIG. 2 (b) is a view in which a lead wire is connected to a terminal hole via a terminal.
FIG. 4A is an enlarged view in the direction of arrow b in FIG.

FIG. 3 is a flowchart showing a manufacturing process of the ground terminal block of FIG. 1;

FIG. 4 is a front view showing a hardness measurement position on a ground terminal block by a micro-Vickers hardness tester.

5A and 5B show an aluminum alloy grounding terminal block according to another embodiment of the present invention. FIG. 5A is a front view, and FIG. 5B is a side view.

FIG. 6 is a perspective view showing a conventional general ground terminal block 50 (conventional product A).

[Explanation of symbols]

 1 ・ 1 ′ Ground terminal block 1a Long piece 1b Short piece 2 Terminal hole 3 Plating part 4 Painting (part) 5 Terminal 6 Lead wire

 ──────────────────────────────────────────────────続 き Continued from the front page (72) Inventor Yoshiaki Ooka 2-1-1-18 Wadayama-dori, Hyogo-ku, Kobe-shi, Hyogo Kawasaki Heavy Industries, Ltd. Hyogo Plant (72) Inventor Kiyomori Nakano Wada, Hyogo-ku, Kobe-shi, Hyogo No. 2-18-18 Yamadori Inside the Hyogo Plant of Kawasaki Heavy Industries, Ltd. 6-11-7 Fukushima, Fukushima-ku, Osaka-shi F-Term in Todensha Co., Ltd. (Reference) 4K022 AA02 AA31 AA41 BA14 BA16 BA25 BA32 BA35 BA36 CA02 CA08 DA01 DA03 DB29 EA04 4K044 AA06 AB05 BA06 BA10 BA21 BB04 BB10 BC02 BC14 CA15 CA18 CA53

Claims (3)

[Claims] A terminal hole for connecting a lead wire is provided near an end on one long side in a substantially L-shape or the like when viewed from the side, and the end near the long side including the terminal hole and its periphery is plated. In an aluminum alloy grounding terminal block in which an epoxy resin coating is applied around a boundary between a plating layer and an aluminum alloy base material, the plating layer is a base plating layer of electroless nickel / phosphorus, an intermediate plating layer of electrolytic copper, and An aluminum alloy ground terminal block characterized by a three-layer structure consisting of electroless nickel and phosphorus finish plating layers. 2. The aluminum alloy ground terminal block according to claim 1, wherein the thickness of the base plating layer is 3 μm, the thickness of the intermediate plating layer is 20 μm, and the thickness of the finish plating layer is 5 μm. 3. An end portion of an aluminum alloy grounding terminal block material having a substantially L-shaped side view and provided with a hole for connecting a lead wire near an end portion on one long side, including a terminal hole and its periphery. After masking the portion other than the near plating portion with a tape or the like, the base material surface of the plating portion is subjected to alkali etching treatment, and then subjected to a zinc / nickel substitution treatment to form a zinc / nickel coating on the surface. After electrolytic nickel plating and washing with water, electrolytic copper plating as intermediate plating and washing with water, then electroless nickel plating as finishing plating and washing again with water, removing the masking tape etc. and drying, and finishing plating A method for manufacturing an aluminum alloy ground terminal block, which comprises applying an epoxy resin coating around a boundary between a layer and a substrate.