JP4279645B2 - Band-shaped electrical contact material and method for producing the same - Google Patents

Description

  The present invention relates to an electrical contact material used by being joined to a base material and an electrical contact piece formed by joining the electrical contact material to the base material, and more particularly to a strip-shaped electrical contact material and an electrical contact piece using the same.

As a belt-shaped electrical contact material, for example, there is a so-called back soldering type material in which a back surface (base material side surface) is coated with a brazing material (see Patent Document 1).
German Patent Application Publication No. 3315498

And as a method of manufacturing electrical contact pieces such as a brush for a motor and a contact for a relay using a strip-shaped electrical contact material, for example, a strip-shaped clad material obtained by joining a strip-shaped base material and a strip-shaped contact material in an overlapping manner There is a method of manufacturing an electrical contact piece of a desired shape by press punching the obtained band-shaped clad material (see Patent Document 2). In addition, as a method for producing a belt-like clad material, for example, there is a method in which a belt-like base material and a belt-like electric contact material are overlapped and passed between a pair of upper and lower rotating roll electrodes, and energized between both electrodes for seam welding ( (See Patent Document 3).
Japanese Patent Laid-Open No. 5-258637 JP-A-3-35882

  However, using a back-wax type belt-shaped electrical contact material and using the manufacturing method described above to produce an electrical contact piece, the base material and the electrical contact material are separated at the stage of producing the strip-shaped clad material. A well-bonded strip clad material cannot be produced. For example, when seam welding is performed with the base material and the electrical contact material overlapped, the molten brazing material flows out from the edge of the joint surface between the belt-like base material and the belt-like electrical contact material, and a protruding portion is generated. End up. And the said protrusion part may fall out at the time of use of the electrical contact piece manufactured from the clad material. Omission of the protruding portion is not preferable because it causes contact operation failure. Further, when the protruding portion is generated, depending on the protruding amount, the amount of the brazing material on the joining surface is partially insufficient, and the brazing joint strength varies, and the joining state may become unstable.

  The present invention has been made in view of such problems, and provides an electrical contact material and a manufacturing method thereof that can join the base material and the electrical contact material in a good joined state, and the base material and the electrical material. It is an object of the present invention to provide an electric contact piece bonded to a contact material in a good bonded state and a method for manufacturing the same.

  The present invention for solving the above problems comprises an electric contact material layer and a brazing material layer, and a belt-like electrical contact joined to the base material in a state where at least a part of the brazing material layer is in contact with the base material. The material is characterized in that both side edges of the brazing material layer are not in contact with the base material while a part of the brazing material layer is in contact with the base material.

  When joining such a strip-shaped electrical contact material to a strip-shaped base material, first, the surface on the brazing material layer side of the electrical contact material (hereinafter referred to as the back surface) is directed on the base material side. Overlapping. Then, at least a part of the brazing material layer comes into contact with the base material. In addition, as a contact part with a base material, convex shapes, such as the projection shape formed in the back surface of an electrical contact material, can be mentioned, for example. On the other hand, both side edges of the brazing material layer are not in contact with the base material. That is, a gap extending in the longitudinal direction of the strip-shaped electrical contact material is formed between both side edges of the brazing material layer and the base material. When the electrical contact material is heated in a state where there is such a gap, the electrical contact material and the base material are joined in a good joined state, and for example, the brazing material is prevented from protruding from the side edge of the electrical contact material. The reason is not necessarily clear, but when the gap is provided, when heated, the brazing material on both side edges corresponding to the gap starts to melt after the brazing material in contact with the base material. It is speculated that this may be related. That is, it is considered that when the melting start timing of both side edges of the brazing filler metal layer is delayed when heated, the protrusion of the brazing filler metal from both sides is suppressed. When the protrusion is prevented, the occurrence of a shortage of brazing material on the joining surface is prevented, and the joining state is prevented from becoming unstable due to variations in brazing joining strength. In addition, since the protruding part, which has been a problem in the past, is no longer dropped during the use of the finally produced electrical contact piece, it is possible to prevent the occurrence of contact failure due to the falling off of the protruding part. The

  Various forms can be considered as the form in which the side edge of the brazing material layer is not in contact with the base material. For example, a form in which the thickness of both side edges of the electrical contact material and / or the brazing material layer is made thinner than the thickness of the contact part with the base material so that the both side edges are not in contact with the base material. Form in which a step is provided between both side edge portions of the layer and the contact portion of the base material so that the both side edge portions are not in contact with the base material, or both side edge portions of the surface of the electrical contact material on the brazing material layer side The taper surface can be used to make contact with the base material. And the dimension of the clearance gap formed between the side edge part of a brazing filler metal layer and a base material when an electrical contact material is made to contact a base material has a more preferable thing which is 0.02 mm-0.05 mm. The same applies to not only the electrical contact material according to the present invention but also the electrical contact materials according to other inventions to be described later, but as the base material, for example, phosphor bronze, beryllium copper, brass, copper or the like is used. . Moreover, as a heating method at the time of joining with a base material, the method by the energization heating, such as seam welding, etc. can be mentioned, for example.

  Another invention for solving the above-mentioned problems consists of an electrical contact material layer and a brazing material layer, and in a strip-shaped electrical contact material joined to the base material in a state where the brazing material layer is in contact with the base material, A convex shape is formed on the back surface (surface on the brazing material layer side) of the electrical contact material.

  This convex shape is also called a projection shape, and comes into contact with the base material when the electrical contact material is joined to the base material. In addition, as a specific example of the convex shape, in addition to the shape in which only the convex portion is provided, an uneven shape such as a wave shape can be exemplified. In addition, one or two or more convex shapes and concave / convex shapes are formed according to the joining conditions of the electrical contact material to the base material. When there is such a convex shape, when the electric contact material and the base material are overlapped and heated, melting of the brazing material starts immediately from the position of the convex shape that is in contact with the base material. In particular, when the joining method is seam welding, an effect is obtained that the melting of the brazing material starts very quickly from the contact position. And since the joining of the electrical contact material according to the present invention is a joining performed using a brazing material, the base material temperature at the time of heating can be suppressed lower than that of normal resistance heating welding, and the base material can be melted. This prevents heat effects on the base material to a minimum. For example, since a spring material such as phosphor bronze may be damaged by heat, the spring characteristics may be impaired. Therefore, an electrical contact material that can minimize the heat effect on the base material is extremely useful. Thus, when the strip-shaped electrical contact material having a convex shape is used on the back surface of the electrical contact material, the electrical contact material and the base material are joined in a good joined state. Note that the procedure for joining the strip-shaped electrical contact material to the strip-shaped base material is the same as the procedure described above, so the description thereof is omitted here.

  Yet another invention for solving the above-mentioned problems is a belt-like electrical contact material comprising an electrical contact material layer and a brazing material layer and joined to the base material in a state where the brazing material layer is in contact with the base material. A concave shape is formed on the back surface (surface on the brazing material layer side) of the electrical contact material.

  When the concave shape is provided on the back surface, when the electrical contact material is stacked on the base material, a gap is formed between the electrical contact material and the base material at a position corresponding to the concave shape. This gap is used as a portion for storing the brazing material melted by the subsequent heating. If there is a part where the brazing material is accumulated, the flow of the molten brazing material is suppressed and the brazing material is prevented from protruding from the side edge of the electrical contact material. Joined in state. In addition, as a specific example of the concave shape, in addition to the shape in which only the concave portion is provided, an uneven shape such as a wave shape can be exemplified. In addition, one or two or more concave shapes and concave / convex shapes are formed according to the joining conditions of the electrical contact material to the base material.

  The contact material layer of the electrical contact material is not particularly limited, but is formed of a silver contact material or a main layer made of a silver-oxide contact material and a brazing material layer side of the main layer. What consists of a silver layer to be formed is preferable. Examples of silver-based contact materials include Ag-based contact materials such as AgCu-based and AgNi-based contact materials. Examples of the silver-oxide contact material include a silver-tin oxide contact material and a silver-tin oxide-indium oxide contact material. Providing a silver layer on the brazing material layer side of the silver-oxide-based contact material provides advantages such as relatively easy welding.

  As described so far, when the strip-shaped electrical contact material according to the present invention is used, the electrical contact material and the base material can be joined in a good joined state. For example, the brazing material is prevented from protruding from both side edges of the electrical contact material. And the electrical contact piece manufactured using such an electrical contact material is excellent in durability that an electrical contact material is hard to peel off. Examples of the electric contact piece include a brush for a motor, a contact for a relay, an opening / closing contact of an electromagnetic switch, or a contact of a general-purpose switch. The electrical contact pieces include those in which the electrical contact material is bonded only to one surface of the base material and those in which the electrical contact material is bonded to both surfaces of the base material.

  Moreover, as a manufacturing method of the strip | belt-shaped electrical contact material which concerns on this invention, the following methods are preferable. That is, in a method of manufacturing a belt-shaped electrical contact material by passing between a pair of upper and lower rotating rolls in a state in which the belt-shaped electrical contact material layer and the belt-shaped brazing material layer are overlapped with each other, disposed on the brazing material layer side As one of the rotating rolls, it is preferable to use a roll having a convex shape that is processed so that both side edge portions of the brazing material layer are not in contact with the base material on the outer peripheral surface in contact with the brazing material layer. Thus, when the convex shape as described above is provided on the outer peripheral surface of one rotating roll, both side edges are not in contact with the base material in a state where a part of the brazing material layer is in contact with the base material. The strip-shaped electrical contact material can be easily manufactured.

  And as one rotating roll, what has the concave shape or uneven | corrugated shape for forming a projection shape in the outer peripheral surface which contact | connects a brazing material layer in the brazing material layer side surface of an electrical contact material is preferable. If such a concave shape or an uneven shape is provided on the outer peripheral surface of one rotating roll, a projection shape can be easily formed on the surface of the contact material layer on the brazing material layer side.

  Further, the band-shaped electrical contact material obtained by the above manufacturing method is bonded to the surface of the band-shaped base material made of the material for the base material of the electrical contact piece, and the electrical contact having a predetermined shape is obtained from the obtained band-shaped clad material. An electrical contact piece can be easily manufactured by cutting out the piece.

  As described above, when the electrical contact material according to the present invention is used, the electrical contact material and the base material can be joined in a good joined state, and the brazing material is prevented from protruding from both side edges of the electrical contact material. And the electrical contact piece which consists of the base material and electrical contact material which were favorably joined can be manufactured.

  Hereinafter, preferred embodiments of a so-called back soldering type electrical contact material according to the present invention will be described with reference to the drawings.

Manufacture of electrical contact material First, a contact material (AgSnO ₂ In ₂ O ₃ ) made of a contact material of a strip-shaped silver-tin oxide-indium oxide system with a silver layer (Ag) attached on one side, and a strip-shaped brazing material ( JIS BCuP-5, Ag: 15%, P: 5%, Cu: balance) were prepared. Then, both belt-like materials are continuously joined by a seam welding method using a pair of rotating roll electrodes, and as shown in FIG. 1, a back comprising a belt-like contact material layer 2 and a belt-like thin brazing material layer 3. A brazed belt-shaped electrical contact material 1 was obtained. Reference numeral “2a” indicates a silver layer.

  As shown in FIG. 1, the surface of the electrical contact material 1 on the contact material layer 2 side is a flat curved surface with no irregularities. On the other hand, the back surface (surface on the brazing filler metal layer 3 side) 10 has irregularities. Specifically, as shown in FIG. 2, a flat surface portion 11 and a projection shape (convex shape) 13 sandwiched between the concave shapes 12 and 14 are formed on the back surface 10. Further, both side edge portions 15 of the brazing material layer 3 are stepped with respect to the flat surface portion 11 that contacts the base material 6 and the front end portion of the projection shape 13 when joined to the base material 6 (see FIG. 4A). It has been.

  And in this embodiment, such a strip | belt-shaped electrical contact material 1 was manufactured by seam-welding the strip | belt-shaped contact material 2 and the strip | belt-shaped brazing material 3 as mentioned above. In the seam welding, a pair of rotating roll electrodes (hereinafter simply referred to as rolls) 4 and 5 shown in FIG. 3 were used. As shown in the drawing, both the rolls 4 and 5 have groove portions 40 and 50 formed on the cylindrical side surface over the entire circumference. The groove portion 40 of the upper roll 4 disposed on the belt-shaped contact material 2 side has a U-shaped cross-sectional shape (cross-sectional shape in the roll rotation axis direction), and the cross-sectional shape of the bottom surface 41 is a straight line.

  On the other hand, the cross-sectional shape of the groove portion 50 of the roll 5 disposed on the belt-like brazing material 3 side is roughly U-shaped, but the cross-sectional shape of the bottom surface 51 is uneven. That is, as shown in FIG. 3, the lower roll 5 includes an annular convex shape 51 a and an annular concave shape 51 b formed on the bottom surface 51 of the groove portion 50 on the outer surface over the entire circumference. An annular convex shape 51c and an annular convex shape 51d formed so as to be continuous with the convex shape 51c are provided. Of these, the convex shapes 51 a and 51 c are formed on the concave shapes 12 and 14 of the back surface 10 of the electrical contact material 1 and on the brazing material layer 3 side surface of the contact material layer 2 along the concave shapes 12 and 14. The concave shapes 22 and 24 (see FIG. 4A) to be formed are formed. And the concave shape 51b is a projection shape (convex shape) formed on the projection shape 13 of the back surface 10 of the electrical contact material 1 and the surface on the brazing filler metal layer 3 side of the contact material layer 2 along the projection shape 13. 23 (see FIG. 4A). Further, the convex shape 51d forms a step between the side edge portions 15 (see FIG. 2) of the brazing material layer 3 and the portions where the flat surface portion 11 and the projection shape 13 are formed. Since the seam welding method is the same as the normal method except that the shape of the roll electrode is different, the detailed description thereof is omitted.

Manufacture of electrical contact pieces First, in addition to the back-wax type belt-shaped electrical contact material 1 obtained by the above-described manufacturing method, a strip-shaped base material 6 for electrical contact pieces (see FIG. 4B) was prepared. The base material 6 has a flat upper surface, that is, a surface with which the brazing material layer 3 of the electrical contact material 1 is brought into contact. Then, the two strips 1 and 6 were overlapped and continuously seam welded to produce a top lay type strip clad material 7 as shown in FIG.

  In a state in which the two strips 1 and 6 are overlapped, the electrical contact material 1 contacts the base member 6 at the flat portion 11 and the tip of the object shape 13 (see FIG. 4A). The dimension L of the gap C1 between the side edge 15 of the brazing filler metal layer 3 and the base material 6 in the overlapped state was 0.03 mm. Further, as shown in FIG. 4C, in the belt-like clad material 7 using the back-wax-type belt-like electrical contact material 1 of the present embodiment, the brazing material protrudes from the side edge of the electrical contact material 1. Was prevented. As the reason for preventing the protrusion, as shown in FIGS. 4A and 4C, a gap C1 is formed between the side edge 15 of the brazing filler metal layer 3 and the base material 6 during the seam welding. The non-contact state is secured, the projection shape 23 is formed, and the molten brazing material is secured at the position corresponding to the concave shapes 22 and 24 with a gap C2 sandwiched between the contact material layer 2 and the base material 6 It is thought that it was possible to accumulate.

  Then, the obtained band-like clad material 7 was punched to obtain an electrical contact piece 8 as shown in FIG. The seam welding method is the same as the conventional method used for the production of the band-like clad material, and therefore detailed description thereof is omitted.

Evaluation of the hardness of the joint of the belt-like clad material The Vickers hardness (HV) of the electric contact material 1 and the base material 6 before seam welding and the belt-like clad material 7 obtained in the course of manufacturing the electric contact piece 8 are configured. The Vickers hardness of the contact material layer 2 and the base material 6 was measured. The measurement results are shown in Table 1.

Evaluation of Bonding Strength of Band- shaped Cladding Material The bonding strength between the electrical contact material 1 and the base material 6 in the band-shaped cladding material 7 was measured. Here, the belt-like clad material 7 is bent by 180 ° so that the longitudinal fold line enters the center in the width direction, and the joining area in that state is joined based on whether or not it is 75% or more of the joining area before the folding. The quality of the strength was evaluated. The measurement results are shown in Table 2. In the table, “◯” indicates that the bonded area after bending was 75% or more.

  As can be seen from Tables 1 and 2, here, the conditions of the width and total thickness of the electrical contact material and the conditions of the material, width and thickness of the base material are variously changed to change the Vickers hardness and bonding strength. Was measured.

  As shown in Table 1, when the electrical contact material of the embodiment is used, the base material and the electrical contact material before and after welding, regardless of conditions such as the thickness of the electrical contact material and the material and thickness of the base material. Hardness did not change. As a result, according to the present embodiment, it has been found that the characteristics of the base material do not change.

  As shown in Table 2, when the electrical contact material of the embodiment is used, the electrical contact material is joined in a good joined state regardless of conditions such as the thickness of the electrical contact material and the material and thickness of the base material. Later, sufficient bonding strength was obtained.

  As can be understood from the above description, one of the characteristics of the electrical contact material according to the present invention is that the thickness of the side edge portion of the brazing material layer is reduced. In addition to what has been described so far, various shapes such as the shapes described below can be considered. In addition, in the electrical contact material 1a (refer FIG. 6) demonstrated next, the same code | symbol shall be attached | subjected about the matter similar to the electrical contact material 1 demonstrated previously, and the detailed description is abbreviate | omitted.

  The strip-shaped electrical contact material 1a shown in FIG. 6 is of a back solder type comprising a contact material layer 2 having a silver layer 2a (thickness 0.05 mm) and a brazing material layer 3 (thickness 0.03 mm). There is a flat portion 11 at the center of the back surface 10. And the both-sides edge part 15 of the brazing filler metal layer 3 is continued to the plane part 11 via the level | step difference 11a (height dimension L2 is 0.03 mm). Therefore, when the strip-shaped electrical contact material 1a is stacked on the base material 6, as in the case of the electrical contact material 1 described above, the flat surface portion 11 contacts the base material 6, and the side edge portion 15 and the base material 6 A gap (a gap similar to the gap C1 (see FIG. 4A)) is generated between them. Thus, if the side edge 15 and the base material 6 can be brought into a non-contact state, the same effect as that of the electrical contact material 1 can be obtained at the time of joining, and the electrical contact material 1a and the base material 6 can be obtained. Can be joined in a good joined state.

  As can be seen from the above description, according to the present embodiment, the electrical contact material and the base material can be satisfactorily joined by seam welding, and the brazing material is prevented from protruding from both side edges of the electrical contact material during seam welding. Is done. Therefore, it is possible to prevent the bonding strength from being varied. Moreover, if the strip | belt-shaped clad material obtained in this way is used, the electrical contact piece which does not have a protrusion part will be manufactured by stamping this. By using this, it is possible to prevent the occurrence of malfunction due to the dropout of the protruding portion when the electric contact piece is used.

It is a perspective view which shows the strip | belt-shaped electrical contact material of embodiment which has a cross section in part. It is an arrow line view which shows the state seen from the arrow A direction of FIG. It is a front view which shows the principal part of a pair of rotary roll electrode used by seam welding. (A) is an expanded sectional view which shows the principal part of the state which accumulated the electrical contact material of embodiment on the base material, (b) is a perspective view which shows the strip | belt-shaped clad material obtained after seam welding, (c) is an arrow view which shows the state seen from the direction of arrow B of (b). It is a perspective view which shows the electrical contact piece obtained from a clad material. It is sectional drawing which shows the cross-sectional shape and structure of the strip | belt-shaped electrical contact material of another embodiment.

Explanation of symbols

1, 1a Electrical contact material 2 Contact material, contact material layer (electric contact material layer)
2a Silver layer 3 Brazing material, brazing material layer 4,5 roll (rotating roll)
6 Base material 7 Strip clad brazing material 8 Electrical contact piece 10 Back surface of electrical contact material (surface on the brazing material layer side of electrical contact material)
11 Plane part (contact part with base material)
13 Projection shape (convex shape, contact part with base material)
15 Side edge 23 of electric contact material Projection shape 51b of brazing material layer side surface of contact material layer annular concave shape 51d of lower roll annular convex shape of lower roll

Claims (5)

It consists of a strip-shaped electrical contact material layer (2) and a strip-shaped brazing material layer (3) covering the back surface of the electrical contact material layer, and at least a part of the brazing material layer is in contact with the base material. In the strip-shaped electrical contact material (1) to be joined to the material,
The brazing material layer (3) covering the back surface of the electrical contact material layer has a uniform thickness,
The brazing material layer (3) is formed with a flat surface portion (11) in contact with the base material at the center at the joint surface to the base material.
On both sides of the flat portion, convex portions that are sandwiched by concave portions (12, 14) that are concave with respect to both side edge portions (15) of the brazing material layer and the flat portion and that contact the base material. A projection portion (13) having a shape is formed;
Further, in a state where the brazing material layer is in contact with the base material, both the side edge portions (15) of the brazing material layer are flat and are not in contact with the base material. An electrical contact material characterized in that a step is provided with respect to the tip of the part. The electrical contact material layer is composed of a silver-based contact material, or a main layer composed of a silver-oxide-based contact material and a silver layer formed on the brazing material layer side of the main layer. Item 2. The strip-shaped electrical contact material according to Item 1. An electrical contact piece formed by joining the electrical contact material according to claim 1 or 2 to a base material. A method for producing an electrical contact material according to claim 1 or claim 2, comprising:
Including a step of heating while passing between a pair of upper and lower rotating rolls in a state where the belt-like electrical contact material layer and the belt-like brazing material layer are overlapped,
One rotating roll arranged on the belt-like brazing filler metal layer side has a groove (50) in contact with the brazing filler metal layer on the outer peripheral surface, a flat bottom portion (51) at the center thereof, and recesses and recesses on both sides of the bottom portion. An annular concavo-convex shape portion (51a, 51b, 51c) for forming a projection portion, and a convex shape portion (51d) processed so that both side edge portions of the brazing material layer are not in contact with the base material The manufacturing method of the strip | belt-shaped electrical contact material which is. The strip-shaped electrical contact material obtained by the manufacturing method according to claim 4 is joined to the surface of a strip-shaped base material made of a base material for an electrical contact piece, and a predetermined shape is formed from the obtained strip-shaped clad material. The manufacturing method of the electrical contact piece which cuts out an electrical contact piece.

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