WO2018043308A1 - Press-fit terminal and substrate connector - Google Patents

Press-fit terminal and substrate connector Download PDF

Info

Publication number
WO2018043308A1
WO2018043308A1 PCT/JP2017/030434 JP2017030434W WO2018043308A1 WO 2018043308 A1 WO2018043308 A1 WO 2018043308A1 JP 2017030434 W JP2017030434 W JP 2017030434W WO 2018043308 A1 WO2018043308 A1 WO 2018043308A1
Authority
WO
WIPO (PCT)
Prior art keywords
copper
base material
press
coating layer
fit terminal
Prior art date
Application number
PCT/JP2017/030434
Other languages
French (fr)
Japanese (ja)
Inventor
照善 宗像
Original Assignee
株式会社オートネットワーク技術研究所
住友電装株式会社
住友電気工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 株式会社オートネットワーク技術研究所, 住友電装株式会社, 住友電気工業株式会社 filed Critical 株式会社オートネットワーク技術研究所
Publication of WO2018043308A1 publication Critical patent/WO2018043308A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R12/00—Structural associations of a plurality of mutually-insulated electrical connecting elements, specially adapted for printed circuits, e.g. printed circuit boards [PCB], flat or ribbon cables, or like generally planar structures, e.g. terminal strips, terminal blocks; Coupling devices specially adapted for printed circuits, flat or ribbon cables, or like generally planar structures; Terminals specially adapted for contact with, or insertion into, printed circuits, flat or ribbon cables, or like generally planar structures
    • H01R12/50—Fixed connections
    • H01R12/51—Fixed connections for rigid printed circuits or like structures
    • H01R12/55—Fixed connections for rigid printed circuits or like structures characterised by the terminals
    • H01R12/58—Fixed connections for rigid printed circuits or like structures characterised by the terminals terminals for insertion into holes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R13/00—Details of coupling devices of the kinds covered by groups H01R12/70 or H01R24/00 - H01R33/00
    • H01R13/02—Contact members
    • H01R13/03—Contact members characterised by the material, e.g. plating, or coating materials

Definitions

  • the present invention relates to a press-fit terminal and a connector for a board, and more specifically, includes a press-fit terminal made of a copper alloy as a base material and press-fitted into a through hole provided in the board, and such a press-fit terminal.
  • the present invention relates to a board connector.
  • a press-fit terminal having a board connection portion that is press-fitted and connected to a through-hole provided in a printed circuit board (PCB) is generally configured using copper or a copper alloy as a base material for reasons such as high conductivity.
  • Specific copper alloys used for the base material of the press-fit terminal include phosphor bronze (Cu—Sn alloy), Corson alloy (Cu—Ni—Si alloy), etc. as described in Patent Document 2. Can be mentioned.
  • a tin layer is formed at least on the surface of the electrical connection part through a base metal layer as appropriate in order to ensure connection reliability in the electrical connection part. Often done.
  • copper or a copper alloy is widely used as a base material for a press-fit terminal, but copper is a relatively expensive metal. Therefore, when a press fit terminal is configured using copper or a copper alloy having a large copper content as a base material, the material cost required for manufacturing the press fit terminal is increased. In addition, the material cost is likely to be affected by fluctuations in the copper market.
  • a press-fit terminal using a copper alloy having a low copper content as the base material.
  • copper alloys with a low copper content include copper-zinc alloys typified by brass.
  • a copper-zinc alloy is not necessarily suitable for use as a press-fit terminal as it is in terms of material characteristics such as inferior in corrosion resistance compared to copper and many other copper alloys.
  • An object of the present invention is to provide a press-fit terminal capable of compensating for material characteristics of a copper-zinc-based alloy such as low corrosion resistance while using a copper-zinc-based alloy as a base material, and such a press-fit terminal. Another object is to provide a connector for a substrate.
  • a press-fit terminal is a press-fit terminal comprising a base material and a base material coating layer that is made of a metal species different from the base material and covers the surface of the base material.
  • the base material is made of a copper-zinc alloy having a zinc content of 35% by mass or less.
  • the base material coating layer may have a layer made of a metal having higher corrosion resistance than the base material.
  • the base material coating layer may have a nickel coating layer made of nickel or a nickel alloy having a thickness of less than 1.0 ⁇ m.
  • the thickness of the nickel coating layer is preferably 0.3 ⁇ m or more.
  • the substrate coating layer may have a copper coating layer having a thickness of 5 ⁇ m or more made of copper or a copper alloy having higher corrosion resistance than the substrate.
  • the copper coating layer may be made of copper.
  • the thickness of the copper coating layer is preferably 10 ⁇ m or less.
  • the press-fit terminal may have a surface layer made of tin or a tin alloy exposed on the outermost surface, covering the surface of the base material coating layer at least at the electrical connection portion of the press-fit terminal.
  • the thickness of the surface layer is preferably 0.1 ⁇ m or more and 1.5 ⁇ m or less.
  • the board connector according to the present invention includes the press-fit terminal as described above.
  • the press-fit terminal according to the invention is based on a copper-zinc alloy, but the zinc content is 35% by mass or less. Thereby, a certain degree of corrosion resistance can be secured in the base material itself made of the copper-zinc alloy. Further, since the surface of the base material is coated with a base material coating layer made of a different metal species, the copper-zinc system can be used depending on the properties imparted by the metal species constituting the base material coating layer, such as further improvement in corrosion resistance. The material properties of the alloy can be supplemented.
  • the base material coating layer has a layer made of a metal having higher corrosion resistance than the base material
  • the corrosion resistance of the copper-zinc alloy is supplemented, and the press fit terminal as a whole can easily obtain high corrosion resistance.
  • the substrate coating layer has a nickel coating layer made of nickel or a nickel alloy having a thickness of less than 1.0 ⁇ m
  • the substrate made of a copper-zinc alloy when the press-fit terminal is heated.
  • the diffusion of copper constituting the outermost surface of the press-fit terminal is suppressed by the presence of the nickel coating layer.
  • the heat resistance of a press fit terminal can be improved.
  • Nickel and nickel alloys have high hardness and are liable to crack when deformed.
  • the thickness of the nickel coating layer is suppressed to less than 1.0 ⁇ m, the nickel coating layer itself cracks and the stress associated therewith.
  • the crack of the base material by concentration can be suppressed. Since cracking of the nickel coating layer and the substrate can lead to corrosion of the substrate, limiting the thickness of the nickel coating layer to less than 1.0 ⁇ m is also effective for maintaining the corrosion resistance of the substrate.
  • the thickness of the nickel coating layer is 0.3 ⁇ m or more, the diffusion of copper from the base material at a high temperature can be effectively suppressed.
  • the substrate coating layer has a copper coating layer made of copper or a copper alloy having a higher corrosion resistance than the substrate and having a thickness of 5 ⁇ m or more
  • the substrate made of a copper-zinc alloy
  • the thickness of the copper coating layer is 5 ⁇ m or more, the corrosion resistance of the press-fit terminal can be particularly effectively increased. Further, even when the board connecting portion of the press-fit terminal is press-fitted into the through hole of the board, it is easy to maintain a copper coating layer that is resistant to elastic deformation and is not damaged.
  • the copper coating layer is made of copper, the copper coating layer can impart particularly high corrosion resistance to the press-fit terminal.
  • the thickness of the copper coating layer is 10 ⁇ m or less, even when the press-fit terminal is press-fitted into the through hole of the substrate, the press-fit terminal is not easily cracked.
  • the press-fit terminal covers the surface of the substrate coating layer at least in the electrical connection portion and has a surface layer made of tin or a tin alloy exposed on the outermost surface, high connection reliability is achieved in the electrical connection portion. Can be achieved.
  • the connection reliability of the electrical connection portion can be effectively increased without excessively thickening the surface layer, It becomes easy to suppress surface layer scraping.
  • the board connector according to the invention is provided with the press-fit terminal as described above, so that a certain degree of corrosion resistance is secured in the base material itself made of a copper-zinc alloy constituting the press-fit terminal, and the surface thereof is provided.
  • the properties of the copper-zinc alloy constituting the substrate can be supplemented by providing the substrate coating layer to be coated, such as providing further corrosion resistance.
  • the press-fit terminal 2 is an electrical connection terminal having an elongated shape.
  • the press-fit terminal 2 has a board connection portion 20 that is press-fitted and connected to the through hole 30 of the board 3 at one end, and is fitted to the other connection terminal at the other end. It has the terminal connection part 25 connected.
  • the terminal connection portion 25 has the shape of a male fitting terminal.
  • the substrate connecting portion 20 has a pair of bulging pieces 21 and 21 at a portion press-fitted and connected to the through hole 30.
  • the bulging pieces 21 and 21 have a shape that bulges in a substantially arc shape so as to be separated from each other in a direction orthogonal to the axial direction of the press-fit terminal 2 (the vertical direction in FIGS. 1 and 2).
  • the top portion protruding outward is the contact portions 21 a, 21 a that contact the inner peripheral surface of the through hole 30.
  • the maximum radial length of the pair of bulging pieces 21, 21 (the maximum distance between the pair of contact portions 21 a, 21 a) is larger than the inner diameter of the through hole 30.
  • a gap 23 is formed between the pair of bulging pieces 21, 21.
  • the bulging pieces 21 and 21 are compressed so as to be close to each other and elastically deformed. Then, the elastic recovery is performed by the elastic component, and the contact with the inner peripheral surface 31 of the through hole 30 is maintained.
  • a guide portion 22 processed into a tapered shape is formed on the tip end side of the bulging pieces 21, 21 of the substrate connecting portion 20, and plays a role of guiding the substrate connecting portion 20 to the through hole 30.
  • the press-fit terminal 2 having such a shape has a copper-zinc alloy as a base material 10 and a base material coating layer 11 made of a metal species different from the base material 10 on the surface thereof.
  • the terminal material 1 is appropriately provided with a surface layer 12.
  • a substrate connector (PCB connector) 4 includes the press-fit terminal 2 as described above. As shown in FIG. 3, in the board connector 4, a plurality of press-fit terminals 2 are arranged side by side and fixed to a connector housing 40 made of a resin material. The press-fit terminal 2 may be appropriately bent at a portion between the board connecting portion 20 and the terminal connecting portion 25.
  • FIG. 4 the cross section of the terminal material 1 which comprises the press fit terminal 2 is shown typically.
  • the terminal material 1 is made of a copper-zinc alloy as a base material 10.
  • the base material coating layer 11 has coat
  • FIG. The terminal material 1 can be comprised only of the base material 10 and the base material coating layer 11, as shown to Fig.4 (a).
  • a surface layer 12 that covers the surface of the base material coating layer 11 and is exposed on the outermost surface of the terminal material 1 may be further provided.
  • the base material coating layer 11 and the surface layer 12 are made of metal species having a component composition different from that of the base material 10. Both the base material covering layer 11 and the surface layer 12 may be composed of a single layer or a plurality of layers. In these meanings, the substrate covering layer 11 and the surface layer 12 are not strictly distinguished from each other. However, in this specification, in order to impart a function to the substrate 10 and supplement the material properties of the substrate 10. This layer is referred to as the base material coating layer 11, and the layer for controlling and adjusting the outermost surface characteristics of the press-fit terminal 2 such as the electrical characteristics of the electrical connection portions (the substrate connection portion 20 and the terminal connection portion 25) is the surface. This is referred to as layer 12.
  • the base material 10 of the terminal material 1 is made of a copper-zinc alloy having a zinc content of 35% by mass or less.
  • Copper-zinc alloys, as represented by brass, are copper-zinc alloys that contain only copper and zinc in addition to unavoidable impurities, but contain an additive element other than zinc in a smaller amount than zinc. It may be.
  • Copper-zinc alloys tend to have lower corrosion resistance than copper and many other copper alloys by containing zinc. However, by suppressing the zinc content to 35% by mass or less, an extreme decrease in corrosion resistance can be avoided.
  • the copper-zinc binary alloy system when the zinc content is 38% by mass or less, an ⁇ phase having a relatively high corrosion resistance is formed. However, when the zinc content exceeds 38% by mass, a ⁇ phase having a low corrosion resistance is mixed. ⁇ + ⁇ phase is formed.
  • the zinc content is more preferably 30% by mass or less, and even more preferably 25% by mass or less.
  • a general-purpose copper-zinc alloy such as brass has a lower copper content than a copper alloy conventionally used to form the press-fit terminal 2, such as phosphor bronze or a Corson alloy.
  • a copper-zinc alloy as the base material 10
  • the material cost of the press-fit terminal 2 can be suppressed. This is because copper is an expensive metal and is greatly affected by market fluctuations.
  • the zinc content in the substrate 10 is preferably 5% by mass or more, and more preferably 10% by mass or more.
  • the copper-zinc alloy constituting the base material 10 of the terminal material 1 may contain an additive element other than zinc.
  • additive elements include aluminum, iron, manganese, tin and the like.
  • the base material coating layer 11 is made of a metal species having a component composition different from that of the copper-zinc alloy constituting the base material.
  • the copper-zinc alloy is not necessarily a material suitable for constituting the press-fit terminal 2 from the viewpoint of material characteristics such as insufficient corrosion resistance as it is.
  • the material properties of the copper-zinc alloy constituting the base material 10 can be supplemented by the properties provided by the base material coating layer 11.
  • corrosion resistance stress corrosion cracking
  • the copper-zinc alloy constituting the base material 10 by limiting the zinc content to 35% by mass or less, relatively high corrosion resistance can be obtained, for example, press fit in the atmosphere. The minimum corrosion resistance necessary for using the terminal 2 can be ensured.
  • copper-zinc alloys are inferior in corrosion resistance as compared to copper and various copper alloys that have conventionally been used to form press-fit terminals.
  • a base material coating layer 11 made of a metal having higher corrosion resistance than the copper-zinc alloy constituting the base material 10 (that is, a metal having a low ionization tendency or a high standard electrode potential) is formed on the surface of the base material 10.
  • the copper-zinc alloy of the base material 10 is not exposed to the external environment, so that the base material 10 is prevented from being corroded by contact with the external environment. That is, when the base material coating layer 11 compensates for the low corrosion resistance of the base material 10, high corrosion resistance can be achieved as the entire terminal material 1 constituting the press-fit terminal 2.
  • a constituent material of the base material coating layer 11 that can supplement the corrosion resistance of the base material 10 copper, a copper alloy having higher corrosion resistance than the base material 10, nickel, a nickel alloy, or the like can be given.
  • the press-fit terminal 2 is used under a high temperature condition by being heated by an external environment or energization. In this case, the press-fit terminal 2 from the base material 10 toward the surface of the metal layer covering the base material 10 Diffusion of copper and zinc atoms is likely to occur.
  • copper atoms and zinc atoms are oxidized on the outermost surface of the terminal material 1, there is a possibility that adverse effects such as an increase in contact resistance at the electrical connection portions 20 and 25 may occur.
  • the base material 10 at high temperature is provided by providing the base material coating layer 11 on the surface of the base material 10 that can impart heat resistance to the base material 10 in the sense of suppressing diffusion of copper atoms and zinc atoms at high temperature.
  • the diffusion of copper atoms and zinc atoms and the adverse effects associated therewith can be reduced.
  • nickel or a nickel alloy, copper, a copper alloy, etc. can be mentioned as a constituent material of the base material coating layer 11 which can provide heat resistance to the base material 10.
  • the base material coating layer 11 may be composed of a plurality of metal layers.
  • a base material covering layer 11 by laminating a plurality of metal layers that can impart the same properties, the properties can be further enhanced and imparted to the base material 10.
  • a plurality of properties can be imparted to the substrate 10 by laminating a plurality of metal layers that can impart different properties to the substrate 10 to form the substrate coating layer 11.
  • Another metal layer can be provided for the purpose of increasing the thickness.
  • the base material coating layer 11 is provided on the entire surface of the base material 10 constituting the press-fit terminal 2, for example, the surface of the electrical connection part (the substrate connection part 20 and the terminal connection part 25), etc. It may be provided only on the surface. In particular, when the base material coating layer 11 supplements the corrosion resistance of the base material 10, it is provided on the entire surface of the base material 10 constituting the press-fit terminal 2 from the viewpoint of preventing corrosion of the entire press-fit terminal 2. Is preferred.
  • the surface layer 12 covers the surface of the base material coating layer 11 and is exposed on the outermost surface of the terminal material 1, and controls and adjusts the surface characteristics of the terminal material 1.
  • a metal layer that can improve the connection reliability of the electrical connection portions 20 and 25 can be exemplified.
  • Examples of such a surface layer 12 include those made of tin or a tin alloy. Tin has high electrical conductivity and low hardness, and the oxide film formed on the surface is easily destroyed. Therefore, it is exposed to the outermost surface of the electrical connection portions 20 and 25, thereby exhibiting low contact resistance and high connection. Reliability can be given. In particular, if the thickness of the surface layer 12 made of tin or tin alloy is 0.1 ⁇ m or more, the effect of improving the connection reliability is excellent.
  • the thickness is set to 1.5 ⁇ m or less, further 1.0 ⁇ m or less, the connection reliability can be sufficiently improved without excessively thickening the surface layer 12, and soft tin It becomes easy to prevent the surface layer 12 from being scraped by abrasion.
  • substrate coating layer 1 Case of nickel or nickel alloy
  • the substrate coating layer 11 is a nickel coating layer 11a made of nickel or a nickel alloy
  • the nickel coating layer 11a may be made of only nickel except for inevitable impurities, or may be made of a nickel alloy containing nickel as a main component and containing other elements.
  • the nickel coating layer 11a may be exposed on the outermost surface of the terminal material 1 as shown in FIG. 4A, but the surface of the nickel coating layer 11a is formed on the surface layer 12 made of tin or a tin alloy as shown in FIG. Is preferably coated.
  • the nickel coating layer 11a exhibits higher corrosion resistance than many copper-zinc alloys, and can serve to supplement the corrosion resistance of the substrate 10.
  • nickel and nickel alloys can prevent the diffusion of copper atoms. Therefore, by providing the nickel coating layer 11a on the surface of the base material 10, the copper atoms constituting the base material 10 diffuse on the surface of the terminal material 1 (the surface of the nickel coating layer 11a itself or the surface of the surface layer 12). Can be suppressed.
  • the terminal material 1 is heated to a high temperature, if copper atoms diffuse to the outermost surface of the terminal material 1 and undergo oxidation, there is a possibility that the contact resistance of the electrical connection portions 20 and 25 may be increased.
  • the coating layer 11a prevents the diffusion of copper atoms, thereby suppressing such a phenomenon and imparting heat resistance to the terminal material 1.
  • the thickness of the nickel coating layer 11a is preferably 0.3 ⁇ m or more.
  • Nickel and nickel alloy are hard metals, and when the board connection portion 20 of the press-fit terminal 2 on which the nickel coating layer 11a is formed is press-fitted into the through hole 30 of the board 3 as shown in FIG. If the material 1 is deformed, the nickel coating layer 11a may break. Further, the stress concentrates on the location where the nickel coating layer 11a is cracked, which may lead to cracking of the base material 10. Such a phenomenon of cracking is more likely to occur as the nickel coating layer 11a is thicker. Furthermore, the crack of the nickel coating layer 11a and the base material 10 can also lead to a situation where the base material 10 is corroded from those cracked portions.
  • the thickness of the nickel coating layer 11a is preferably less than 1.0 ⁇ m.
  • the thickness of the nickel coating layer 11a is more preferably 0.8 ⁇ m or less, and even more preferably 0.6 ⁇ m or less.
  • substrate coating layer 11 is a copper coating layer 11b made of copper or a copper alloy.
  • the copper coating layer 11b may be made of only copper except for inevitable impurities, or may be made of copper alloy containing copper as a main component and containing other elements. However, when made of a copper alloy, a copper alloy having higher corrosion resistance than that of the copper-zinc alloy constituting the substrate 10 is selected.
  • the copper coating layer 11b may be exposed on the outermost surface of the terminal material 1 as shown in FIG. 4 (a), but the surface is formed on the surface layer 12 made of tin or a tin alloy as shown in FIG. 4 (b). Is preferably coated.
  • the copper coating layer 11b is preferably made of copper rather than a copper alloy.
  • concrete examples include brass, high-strength brass, bronze, phosphor bronze, lead bronze, aluminum bronze, silgin bronze, beryllium copper, chromium copper, and the like. Can do.
  • the thickness of the copper coating layer 11b is preferably 5 ⁇ m or more.
  • the press-fit terminal can withstand use under normal conditions such as in the atmosphere by limiting the zinc content to 35% by mass or less. 2 can ensure the minimum corrosion resistance, but by using the copper coating layer 11b having a thickness of 5 ⁇ m or more, corrosion is very likely to proceed as in the ammonia atmosphere applied in the following examples. Even under severe conditions, corrosion of the substrate 10 can be highly suppressed.
  • the thickness of the copper coating layer 11b is set to 5 ⁇ m or more, when the press-fit terminal 2 is elastically deformed by press-fitting the board connecting portion 20 of the press-fit terminal 2 into the through hole 30 of the board 3, Damage such as cracking of the coating layer 11b can be suppressed.
  • the thickness of the copper coating layer 11b is preferably 10 ⁇ m or less. If the copper coating layer 11b becomes too thick, the thickness of the terminal material 1 as a whole becomes too large in comparison with the inner diameter of the through hole 30 of the substrate 3, and the terminal connecting portion 20 is press-fitted into the through hole 30 at the terminal. This is because cracks are likely to occur in the material 1.
  • the copper coating layer 11b can also impart heat resistance in addition to the effect of imparting corrosion resistance to the base material 10. That is, when the temperature becomes high, the copper coating layer 11b prevents zinc atoms from diffusing from the base material 10 made of a copper-zinc alloy to the outermost surface of the terminal material 1 and being oxidized to increase the contact resistance. be able to.
  • the nickel coating layer 11a and the copper coating layer 11b may be stacked and used. In that case, the copper coating layer 11b may be disposed on the substrate 10 side.
  • a terminal material was prepared by forming a nickel coating layer made of nickel and a surface layer made of tin in this order on the surface of a base material made of a copper-zinc alloy by plating.
  • the zinc content in the substrate was 25% by mass.
  • the thickness of the nickel coating layer was changed in the range of 0.3 to 1.0 ⁇ m.
  • the thickness of the tin surface layer was 0.5 ⁇ m.
  • FIG. 5 shows a photograph of the vicinity of the edge of the through hole in a state in which the board connecting portion of the press fit terminal is press-fitted into the through hole of the board.
  • Table 1 shows the evaluation results of the presence or absence of cracks in the nickel coating layer together with the thickness of the nickel coating layer.
  • FIG. 5D when the thickness of the nickel coating layer is 1.0 ⁇ m, the base material is exposed in a streak shape at the corner of the press-fit terminal as indicated by the arrow in the figure. Was observed. That is, the nickel coating layer is cracked.
  • FIGS. 5 (a) to 5 (c) where the thickness of the nickel coating layer is thinner than this, such a streak-like substrate is not exposed. That is, the nickel coating layer is not cracked.
  • the thickness of the nickel coating layer is set to less than 1.0 ⁇ m, even if the terminal material is elastically deformed by press-fitting the board connection portion of the press-fit terminal into the through hole of the board, the nickel coating layer It was confirmed that cracking can be avoided.
  • Example preparation A terminal material was prepared by forming a copper coating layer made of copper and a surface layer made of tin in this order on the surface of a base material made of a copper-zinc alloy by plating.
  • the zinc content in the substrate and the thickness of the copper coating layer were changed as shown in Table 2.
  • the thickness of the tin surface layer was 1 ⁇ m.
  • a press-fit terminal similar to the test in the case where the nickel coating layer was provided was formed.
  • substrate which has the same through hole was prepared.
  • Table 2 shows the evaluation results of stress corrosion cracking together with the zinc content in the substrate and the thickness of the copper coating layer.

Landscapes

  • Coupling Device And Connection With Printed Circuit (AREA)

Abstract

Provided is a press-fit terminal that is capable of compensating for material characteristics of a copper-zinc based alloy, such as low corrosion resistance, while using the copper-zinc based alloy as a base material, and a substrate connector provided with such a press-fit terminal. This press-fit terminal has: a base material 10; and a base material cover layer 11 that covers the surface of the base material 10 and that is made of a metal species different from that of the base material 10, wherein the base material 10 is made of a copper-zinc based alloy in which the zinc content is 35% by mass or less. The base material cover layer 11 can be a nickel cover layer 11a made of nickel or a nickel alloy and having a thickness of less than 1.0 µm, or a copper cover layer 11b having a thickness of 5 µm or more and made of copper or a copper alloy higher in corrosion resistance than the base material 10.

Description

プレスフィット端子および基板用コネクタPress-fit terminals and board connectors
　本発明は、プレスフィット端子および基板用コネクタに関し、さらに詳しくは、銅合金を母材としてなり、基板に設けられたスルーホールに圧入接続されるプレスフィット端子、およびそのようなプレスフィット端子を備えた基板用コネクタに関する。 The present invention relates to a press-fit terminal and a connector for a board, and more specifically, includes a press-fit terminal made of a copper alloy as a base material and press-fitted into a through hole provided in the board, and such a press-fit terminal. The present invention relates to a board connector.
　プリント基板（ＰＣＢ）に設けられたスルーホールに圧入接続される基板接続部を有するプレスフィット端子は、従来一般に、導電率の高さ等を理由として、銅または銅合金を基材として構成される（例えば特許文献１）。プレスフィット端子の基材に用いられる具体的な銅合金としては、特許文献２に記載されるようなリン青銅（Ｃｕ－Ｓｎ系合金）、コルソン系合金（Ｃｕ－Ｎｉ－Ｓｉ系合金）等を挙げることができる。そして、銅または銅合金を基材としてなるプレスフィット端子においては、電気接続部における接続信頼性を確保するために、少なくとも電気接続部の表面に、適宜下地金属層を介して、スズ層が形成されることが多い。 A press-fit terminal having a board connection portion that is press-fitted and connected to a through-hole provided in a printed circuit board (PCB) is generally configured using copper or a copper alloy as a base material for reasons such as high conductivity. (For example, patent document 1). Specific copper alloys used for the base material of the press-fit terminal include phosphor bronze (Cu—Sn alloy), Corson alloy (Cu—Ni—Si alloy), etc. as described in Patent Document 2. Can be mentioned. And in press-fit terminals made of copper or copper alloy as a base material, a tin layer is formed at least on the surface of the electrical connection part through a base metal layer as appropriate in order to ensure connection reliability in the electrical connection part. Often done.
特開２００５－２２６０８９号公報JP 2005-226089 A 特開２０１２－１７４４００号公報JP 2012-174400 A
　上記のように、プレスフィット端子の基材としては、銅または銅合金が広く用いられているが、銅は比較的高価な金属である。よって、銅や銅含有量の多い銅合金を基材に用いてプレスフィット端子を構成する場合に、プレスフィット端子の製造に要する材料コストが大きくなる。また、材料コストが銅相場の変動の影響を受けやすくなる。 As described above, copper or a copper alloy is widely used as a base material for a press-fit terminal, but copper is a relatively expensive metal. Therefore, when a press fit terminal is configured using copper or a copper alloy having a large copper content as a base material, the material cost required for manufacturing the press fit terminal is increased. In addition, the material cost is likely to be affected by fluctuations in the copper market.
　そこで、基材に要する材料コストを低減する観点から、銅の含有量の少ない銅合金を基材として用いてプレスフィット端子を構成することが考えられる。銅の含有量の少ない銅合金として、黄銅に代表される銅－亜鉛系合金を挙げることができる。しかし、銅－亜鉛系合金は、銅や他の多くの銅合金と比較して耐食性に劣る等、材料特性の面で、そのままプレスフィット端子として用いるのに必ずしも適しているとは言えない。 Therefore, from the viewpoint of reducing the material cost required for the base material, it is conceivable to form a press-fit terminal using a copper alloy having a low copper content as the base material. Examples of copper alloys with a low copper content include copper-zinc alloys typified by brass. However, a copper-zinc alloy is not necessarily suitable for use as a press-fit terminal as it is in terms of material characteristics such as inferior in corrosion resistance compared to copper and many other copper alloys.
　本発明の課題は、銅－亜鉛系合金を基材として用いながら、耐食性の低さ等、銅－亜鉛系合金の材料特性を補うことができるプレスフィット端子、およびそのようなプレスフィット端子を備えた基板用コネクタを提供することにある。 An object of the present invention is to provide a press-fit terminal capable of compensating for material characteristics of a copper-zinc-based alloy such as low corrosion resistance while using a copper-zinc-based alloy as a base material, and such a press-fit terminal. Another object is to provide a connector for a substrate.
　上記課題を解決するため、本発明にかかるプレスフィット端子は、基材と、前記基材と異なる金属種よりなり、前記基材の表面を被覆する基材被覆層と、を有するプレスフィット端子において、前記基材が、亜鉛含有量が３５質量％以下である銅－亜鉛系合金よりなるものである。 In order to solve the above-mentioned problems, a press-fit terminal according to the present invention is a press-fit terminal comprising a base material and a base material coating layer that is made of a metal species different from the base material and covers the surface of the base material. The base material is made of a copper-zinc alloy having a zinc content of 35% by mass or less.
　ここで、前記基材被覆層は、前記基材よりも耐食性の高い金属よりなる層を有するとよい。 Here, the base material coating layer may have a layer made of a metal having higher corrosion resistance than the base material.
　また、前記基材被覆層は、厚さ１．０μｍ未満のニッケルまたはニッケル合金よりなるニッケル被覆層を有するとよい。この場合に、前記ニッケル被覆層の厚さは、０．３μｍ以上であるとよい。 The base material coating layer may have a nickel coating layer made of nickel or a nickel alloy having a thickness of less than 1.0 μm. In this case, the thickness of the nickel coating layer is preferably 0.3 μm or more.
　あるいは、前記基材被覆層は、銅、または前記基材よりも耐食性の高い銅合金よりなる、厚さ５μｍ以上の銅被覆層を有するとよい。この場合に、前記銅被覆層は銅よりなるとよい。前記銅被覆層の厚さは、１０μｍ以下であるとよい。 Alternatively, the substrate coating layer may have a copper coating layer having a thickness of 5 μm or more made of copper or a copper alloy having higher corrosion resistance than the substrate. In this case, the copper coating layer may be made of copper. The thickness of the copper coating layer is preferably 10 μm or less.
　前記プレスフィット端子は、前記プレスフィット端子の少なくとも電気接続部において前記基材被覆層の表面を被覆して、最表面に露出したスズまたはスズ合金よりなる表面層を有するとよい。この場合に、前記表面層の厚さは、０．１μｍ以上、１．５μｍ以下であるとよい。 The press-fit terminal may have a surface layer made of tin or a tin alloy exposed on the outermost surface, covering the surface of the base material coating layer at least at the electrical connection portion of the press-fit terminal. In this case, the thickness of the surface layer is preferably 0.1 μm or more and 1.5 μm or less.
　本発明にかかる基板用コネクタは、上記のようなプレスフィット端子を備えるものである。 The board connector according to the present invention includes the press-fit terminal as described above.
　上記発明にかかるプレスフィット端子は、銅－亜鉛系合金を基材としてなっているが、その亜鉛含有量は３５質量％以下とされている。これにより、銅－亜鉛系合金よりなる基材自体において、ある程度の耐食性を確保することができる。そして、基材の表面が異なる金属種よりなる基材被覆層によって被覆されていることにより、耐食性のさらなる向上等、基材被覆層を構成する金属種によって付与される特性によって、銅－亜鉛系合金の材料特性を補うことができる。 The press-fit terminal according to the invention is based on a copper-zinc alloy, but the zinc content is 35% by mass or less. Thereby, a certain degree of corrosion resistance can be secured in the base material itself made of the copper-zinc alloy. Further, since the surface of the base material is coated with a base material coating layer made of a different metal species, the copper-zinc system can be used depending on the properties imparted by the metal species constituting the base material coating layer, such as further improvement in corrosion resistance. The material properties of the alloy can be supplemented.
　ここで、基材被覆層が、基材よりも耐食性の高い金属よりなる層を有する場合には、銅－亜鉛系合金の耐食性を補って、プレスフィット端子全体として、高い耐食性を得やすくなる。 Here, when the base material coating layer has a layer made of a metal having higher corrosion resistance than the base material, the corrosion resistance of the copper-zinc alloy is supplemented, and the press fit terminal as a whole can easily obtain high corrosion resistance.
　また、基材被覆層が、厚さ１．０μｍ未満のニッケルまたはニッケル合金よりなるニッケル被覆層を有する場合には、プレスフィット端子が加熱を受けた際に、銅－亜鉛系合金よりなる基材を構成する銅の、プレスフィット端子の最表面への拡散が、ニッケル被覆層の存在によって抑制される。これにより、プレスフィット端子の耐熱性を高めることができる。ニッケルやニッケル合金は、高い硬度を有し、変形時に割れを生じやすいが、ニッケル被覆層の厚さが１．０μｍ未満に抑えられていることにより、ニッケル被覆層自体の割れ、またそれに伴う応力集中による基材の割れを抑制することができる。ニッケル被覆層や基材の割れは、基材の腐食にもつながりうるので、ニッケル被覆層の厚さを１．０μｍ未満に制限することは、基材の耐食性の維持にも有効である。 Further, when the substrate coating layer has a nickel coating layer made of nickel or a nickel alloy having a thickness of less than 1.0 μm, the substrate made of a copper-zinc alloy when the press-fit terminal is heated. The diffusion of copper constituting the outermost surface of the press-fit terminal is suppressed by the presence of the nickel coating layer. Thereby, the heat resistance of a press fit terminal can be improved. Nickel and nickel alloys have high hardness and are liable to crack when deformed. However, since the thickness of the nickel coating layer is suppressed to less than 1.0 μm, the nickel coating layer itself cracks and the stress associated therewith. The crack of the base material by concentration can be suppressed. Since cracking of the nickel coating layer and the substrate can lead to corrosion of the substrate, limiting the thickness of the nickel coating layer to less than 1.0 μm is also effective for maintaining the corrosion resistance of the substrate.
　この場合に、ニッケル被覆層の厚さが、０．３μｍ以上であれば、高温での基材からの銅の拡散を効果的に抑制することができる。 In this case, if the thickness of the nickel coating layer is 0.3 μm or more, the diffusion of copper from the base material at a high temperature can be effectively suppressed.
　あるいは、基材被覆層が、銅、または基材よりも耐食性の高い銅合金よりなる、厚さ５μｍ以上の銅被覆層を有する場合には、銅－亜鉛系合金よりなる基材が、それよりも高い耐食性を有する銅被覆層によって被覆されることにより、プレスフット端子全体としての耐食性の確保を有効に達成することができる。銅被覆層の厚さが５μｍ以上とされることで、プレスフィット端子の耐食性を特に効果的に高めることができる。また、プレスフィット端子の基板接続部を基板のスルーホールに圧入した際にも、弾性変形に耐え、損傷のない銅被覆層を維持しやすい。 Alternatively, when the substrate coating layer has a copper coating layer made of copper or a copper alloy having a higher corrosion resistance than the substrate and having a thickness of 5 μm or more, the substrate made of a copper-zinc alloy Further, by being covered with a copper coating layer having high corrosion resistance, it is possible to effectively achieve ensuring corrosion resistance as the entire press foot terminal. When the thickness of the copper coating layer is 5 μm or more, the corrosion resistance of the press-fit terminal can be particularly effectively increased. Further, even when the board connecting portion of the press-fit terminal is press-fitted into the through hole of the board, it is easy to maintain a copper coating layer that is resistant to elastic deformation and is not damaged.
　この場合に、銅被覆層が銅よりなれば、銅被覆層によって、プレスフィット端子に特に高い耐食性を付与することができる。 In this case, if the copper coating layer is made of copper, the copper coating layer can impart particularly high corrosion resistance to the press-fit terminal.
　銅被覆層の厚さが、１０μｍ以下であれば、プレスフィット端子を基板のスルーホールに圧入した際にも、プレスフィット端子に割れを生じにくい。 If the thickness of the copper coating layer is 10 μm or less, even when the press-fit terminal is press-fitted into the through hole of the substrate, the press-fit terminal is not easily cracked.
　プレスフィット端子が、少なくとも電気接続部において基材被覆層の表面を被覆して、最表面に露出したスズまたはスズ合金よりなる表面層を有する場合には、電気接続部において、高い接続信頼性を達成することができる。 When the press-fit terminal covers the surface of the substrate coating layer at least in the electrical connection portion and has a surface layer made of tin or a tin alloy exposed on the outermost surface, high connection reliability is achieved in the electrical connection portion. Can be achieved.
　この場合に、表面層の厚さが、０．１μｍ以上、１．５μｍ以下であれば、過剰に表面層を厚くすることなく電気接続部の接続信頼性を効果的に高めることができるとともに、表面層の削れを抑制しやすくなる。 In this case, if the thickness of the surface layer is 0.1 μm or more and 1.5 μm or less, the connection reliability of the electrical connection portion can be effectively increased without excessively thickening the surface layer, It becomes easy to suppress surface layer scraping.
　上記発明にかかる基板用コネクタは、上記のようなプレスフィット端子を備えることにより、プレスフィット端子を構成する銅－亜鉛系合金よりなる基材自体においてある程度の耐食性が確保されるとともに、その表面を被覆する基材被覆層によって、さらなる耐食性を付与する等、基材を構成する銅－亜鉛系合金の特性を補うことができる。 The board connector according to the invention is provided with the press-fit terminal as described above, so that a certain degree of corrosion resistance is secured in the base material itself made of a copper-zinc alloy constituting the press-fit terminal, and the surface thereof is provided. The properties of the copper-zinc alloy constituting the substrate can be supplemented by providing the substrate coating layer to be coated, such as providing further corrosion resistance.
本発明の一実施形態にかかるプレスフィット端子の全体構造を示す正面図である。It is a front view showing the whole press fit terminal structure concerning one embodiment of the present invention. プレスフィット端子の基板接続部を基板のスルーホールに圧入する際の状態を示す断面図であり、（ａ）は圧入前、（ｂ）は圧入後の状態を示している。It is sectional drawing which shows the state at the time of press-fitting the board | substrate connection part of a press fit terminal to the through hole of a board | substrate, (a) has shown the state after press-fit, (b). 本発明の一実施形態にかかる基板用コネクタを示す断面図である。It is sectional drawing which shows the connector for boards concerning one Embodiment of this invention. 上記プレスフィット端子の構成材料を示す断面図であり、（ａ）は基材の表面に基材被覆層のみが形成されている場合、（ｂ）は基材の表面に基材被覆層と表面層が形成されている場合を示している。It is sectional drawing which shows the constituent material of the said press fit terminal, (a) is a base material surface, when only the base material coating layer is formed in the surface of a base material, (b) is a base material coating layer and surface on the surface of a base material The case where the layer is formed is shown. ニッケル被覆層の厚さを異ならせた場合の、ニッケル被覆層の割れの有無を示す写真である。It is a photograph which shows the presence or absence of the crack of a nickel coating layer when the thickness of a nickel coating layer is varied.
　以下、図面を用いて本発明の一実施形態にかかるプレスフィット端子および基板用コネクタについて、詳細に説明する。 Hereinafter, a press-fit terminal and a board connector according to an embodiment of the present invention will be described in detail with reference to the drawings.
［プレスフィット端子および基板コネクタの概略］
　まず、本発明の一実施形態にかかるプレスフィット端子および基板用コネクタの概略について説明する。 [Outline of press-fit terminal and board connector]
First, an outline of a press-fit terminal and a board connector according to an embodiment of the present invention will be described.
　図１，２に、本発明の一実施形態にかかるプレスフィット端子２の構造を示す。プレスフィット端子２は、細長い形状を有する電気接続端子であり、一端に、基板３のスルーホール３０に圧入接続される基板接続部２０を有し、他端に、相手方接続端子と嵌合等によって接続される端子接続部２５を有している。図示した例では、端子接続部２５は、雄型の嵌合端子の形状を有している。 1 and 2 show the structure of a press-fit terminal 2 according to an embodiment of the present invention. The press-fit terminal 2 is an electrical connection terminal having an elongated shape. The press-fit terminal 2 has a board connection portion 20 that is press-fitted and connected to the through hole 30 of the board 3 at one end, and is fitted to the other connection terminal at the other end. It has the terminal connection part 25 connected. In the illustrated example, the terminal connection portion 25 has the shape of a male fitting terminal.
　基板接続部２０は、スルーホール３０に圧入接続される部分に、１対の膨出片２１，２１を有している。膨出片２１，２１は、プレスフィット端子２の軸線方向（図１，２の縦方向）と直交する方向に互いに離れるように、略円弧状に膨出した形状を有している。膨出片２１，２１の膨出方向の外側面において、最も外側に突出した頂部が、スルーホール３０の内周面に接触する接点部２１ａ，２１ａとなる。１対の膨出片２１，２１の径方向の最大長さ（１対の接点部２１ａ，２１ａの間の最大の距離）はスルーホール３０の内径よりも大きくなっている。 The substrate connecting portion 20 has a pair of bulging pieces 21 and 21 at a portion press-fitted and connected to the through hole 30. The bulging pieces 21 and 21 have a shape that bulges in a substantially arc shape so as to be separated from each other in a direction orthogonal to the axial direction of the press-fit terminal 2 (the vertical direction in FIGS. 1 and 2). On the outer surface in the bulging direction of the bulging pieces 21, 21, the top portion protruding outward is the contact portions 21 a, 21 a that contact the inner peripheral surface of the through hole 30. The maximum radial length of the pair of bulging pieces 21, 21 (the maximum distance between the pair of contact portions 21 a, 21 a) is larger than the inner diameter of the through hole 30.
　１対の膨出片２１，２１の間には空隙２３が形成されており、この空隙２３により、図２（ｂ）のようにプレスフィット端子２をスルーホール３０に挿入した際に、１対の膨出片２１，２１が、相互に近接するように押し縮められ、弾性的に変形する。そして弾性成分によって弾性回復し、スルーホール３０の内周面３１との接触を保つ。基板接続部２０の膨出片２１，２１よりも先端側には、先細り形状に加工された案内部２２が形成されており、基板接続部２０をスルーホール３０に案内する役割を果たす。 A gap 23 is formed between the pair of bulging pieces 21, 21. When the press-fit terminal 2 is inserted into the through hole 30 as shown in FIG. The bulging pieces 21 and 21 are compressed so as to be close to each other and elastically deformed. Then, the elastic recovery is performed by the elastic component, and the contact with the inner peripheral surface 31 of the through hole 30 is maintained. A guide portion 22 processed into a tapered shape is formed on the tip end side of the bulging pieces 21, 21 of the substrate connecting portion 20, and plays a role of guiding the substrate connecting portion 20 to the through hole 30.
　このような形状を有するプレスフィット端子２は、以下で詳しく説明するように、銅－亜鉛系合金を基材１０とし、その表面に、基材１０と異なる金属種よりなる基材被覆層１１と、適宜表面層１２を有する端子材料１より構成されている。 As will be described in detail below, the press-fit terminal 2 having such a shape has a copper-zinc alloy as a base material 10 and a base material coating layer 11 made of a metal species different from the base material 10 on the surface thereof. The terminal material 1 is appropriately provided with a surface layer 12.
　本発明の一実施形態にかかる基板用コネクタ（ＰＣＢコネクタ）４は、上記のようなプレスフィット端子２を備えるものである。図３に示すように、基板用コネクタ４においては、複数のプレスフィット端子２が並べて配置され、樹脂材料よりなるコネクタハウジング４０に固定されている。プレスフィット端子２は、基板接続部２０と端子接続部２５の間の部位で適宜曲げられてもよい。 A substrate connector (PCB connector) 4 according to an embodiment of the present invention includes the press-fit terminal 2 as described above. As shown in FIG. 3, in the board connector 4, a plurality of press-fit terminals 2 are arranged side by side and fixed to a connector housing 40 made of a resin material. The press-fit terminal 2 may be appropriately bent at a portion between the board connecting portion 20 and the terminal connecting portion 25.
［プレスフィット端子を構成する端子材料］
　図４に、プレスフィット端子２を構成する端子材料１の断面を模式的に示す。端子材料１は、銅－亜鉛系合金を基材１０としてなっている。そして、基材１０の表面を、基材被覆層１１が被覆している。端子材料１は、図４（ａ）に示すように、基材１０と基材被覆層１１のみより構成することができる。あるいは、図４（ｂ）に示すように、基材被覆層１１の表面を被覆して、端子材料１の最表面に露出した表面層１２をさらに設けてもよい。 [Terminal materials constituting press-fit terminals]
In FIG. 4, the cross section of the terminal material 1 which comprises the press fit terminal 2 is shown typically. The terminal material 1 is made of a copper-zinc alloy as a base material 10. And the base material coating layer 11 has coat | covered the surface of the base material 10. FIG. The terminal material 1 can be comprised only of the base material 10 and the base material coating layer 11, as shown to Fig.4 (a). Alternatively, as shown in FIG. 4B, a surface layer 12 that covers the surface of the base material coating layer 11 and is exposed on the outermost surface of the terminal material 1 may be further provided.
　基材被覆層１１および表面層１２は、基材１０とは成分組成の異なる金属種よりなっている。基材被覆層１１、表面層１２とも、単層よりなっても、複数の層よりなってもよい。これらの意味においては、基材被覆層１１と表面層１２は厳密に区別されるものではないが、本明細書においては、基材１０に機能を付与し、基材１０の材料特性を補うための層を基材被覆層１１と称し、電気接続部（基板接続部２０および端子接続部２５）の電気的特性等、プレスフィット端子２の最表面の特性を制御、調整するための層を表面層１２と称する。 The base material coating layer 11 and the surface layer 12 are made of metal species having a component composition different from that of the base material 10. Both the base material covering layer 11 and the surface layer 12 may be composed of a single layer or a plurality of layers. In these meanings, the substrate covering layer 11 and the surface layer 12 are not strictly distinguished from each other. However, in this specification, in order to impart a function to the substrate 10 and supplement the material properties of the substrate 10. This layer is referred to as the base material coating layer 11, and the layer for controlling and adjusting the outermost surface characteristics of the press-fit terminal 2 such as the electrical characteristics of the electrical connection portions (the substrate connection portion 20 and the terminal connection portion 25) is the surface. This is referred to as layer 12.
（基材の構成材料）
　端子材料１の基材１０は、亜鉛含有量が３５質量％以下である銅－亜鉛系合金よりなっている。銅－亜鉛系合金は、黄銅に代表されるように、不可避的不純物以外には銅と亜鉛のみよりなる銅－亜鉛合金であっても、亜鉛以外の添加元素を亜鉛よりも少量だけ含有する合金であってもよい。 (Constituent material of base material)
The base material 10 of the terminal material 1 is made of a copper-zinc alloy having a zinc content of 35% by mass or less. Copper-zinc alloys, as represented by brass, are copper-zinc alloys that contain only copper and zinc in addition to unavoidable impurities, but contain an additive element other than zinc in a smaller amount than zinc. It may be.
　銅－亜鉛系合金は、亜鉛を含有することにより、銅や、他の多くの銅合金よりも耐食性が低くなりやすい。しかし、亜鉛含有量を３５質量％以下に抑えることにより、耐食性の極端な低下を避けることができる。銅－亜鉛二元合金系において、亜鉛含有量が３８質量％以下では、比較的耐食性の高いα相が形成されるが、亜鉛含有量が３８質量％を超えると、耐食性の低いβ相の混在したα＋β相が形成される。亜鉛含有量を３５質量％以下に制限することで、β相の混在を避け、基材１０の耐食性を確保することができる。亜鉛の含有量は、３０質量％以下、さらには２５質量％以下であると、より好ましい。 Copper-zinc alloys tend to have lower corrosion resistance than copper and many other copper alloys by containing zinc. However, by suppressing the zinc content to 35% by mass or less, an extreme decrease in corrosion resistance can be avoided. In the copper-zinc binary alloy system, when the zinc content is 38% by mass or less, an α phase having a relatively high corrosion resistance is formed. However, when the zinc content exceeds 38% by mass, a β phase having a low corrosion resistance is mixed. Α + β phase is formed. By restricting the zinc content to 35% by mass or less, it is possible to avoid the mixing of the β phase and to ensure the corrosion resistance of the substrate 10. The zinc content is more preferably 30% by mass or less, and even more preferably 25% by mass or less.
　黄銅等、汎用的な銅－亜鉛系合金は、リン青銅やコルソン系合金等、プレスフィット端子２を構成するのに従来一般に用いられてきた銅合金よりも銅の含有量が少ないものであり、銅－亜鉛系合金を基材１０として用いることで、プレスフィット端子２の材料コストを抑制することができる。銅は高価な金属であり、相場変動の影響も大きいからである。材料コストの抑制を効果的に達成する観点から、基材１０における亜鉛含有量は、５質量％以上、さらには１０質量％以上であることが好ましい。 A general-purpose copper-zinc alloy such as brass has a lower copper content than a copper alloy conventionally used to form the press-fit terminal 2, such as phosphor bronze or a Corson alloy. By using a copper-zinc alloy as the base material 10, the material cost of the press-fit terminal 2 can be suppressed. This is because copper is an expensive metal and is greatly affected by market fluctuations. From the viewpoint of effectively suppressing the material cost, the zinc content in the substrate 10 is preferably 5% by mass or more, and more preferably 10% by mass or more.
　上記のように、端子材料１の基材１０を構成する銅－亜鉛系合金には、亜鉛以外の添加元素が含まれてもよい。そのような添加元素の例としては、アルミニウム、鉄、マンガン、スズ等を挙げることができる。それらの添加元素を添加することで、強靭性、耐摩耗性、硬さの向上等の効果を得ることができる。 As described above, the copper-zinc alloy constituting the base material 10 of the terminal material 1 may contain an additive element other than zinc. Examples of such additive elements include aluminum, iron, manganese, tin and the like. By adding these additive elements, effects such as improvement of toughness, wear resistance and hardness can be obtained.
（基材被覆層の構成材料）
　上記のように、基材被覆層１１は、基材を構成する銅－亜鉛系合金と成分組成の異なる金属種よりなる。銅－亜鉛系合金は、そのままでは、耐食性が不十分になりやすい等、材料特性の観点から、必ずしもプレスフィット端子２を構成するのに適した材料であるとは言えないが、基材被覆層１１で基材１０を被覆することで、基材被覆層１１が付与する特性によって、基材１０を構成する銅－亜鉛系合金の材料特性を補うことができる。 (Constituent material of base material coating layer)
As described above, the base material coating layer 11 is made of a metal species having a component composition different from that of the copper-zinc alloy constituting the base material. The copper-zinc alloy is not necessarily a material suitable for constituting the press-fit terminal 2 from the viewpoint of material characteristics such as insufficient corrosion resistance as it is. By covering the base material 10 with 11, the material properties of the copper-zinc alloy constituting the base material 10 can be supplemented by the properties provided by the base material coating layer 11.
　基材被覆層１１によって補うべき基材１０の材料特性として、耐食性（耐応力腐食割れ）を例示することができる。上記のように、基材１０を構成する銅－亜鉛系合金において、亜鉛含有量を３５質量％以下に制限しておくことで、比較的高い耐食性を得ることができ、例えば大気中でプレスフィット端子２を使用するのに必要な、最低限の耐食性は確保することができる。しかし、銅や、従来一般にプレスフィット端子を構成するのに用いられてきた各種銅合金に比べると、銅－亜鉛系合金は耐食性に劣る。そこで、基材１０を構成する銅－亜鉛系合金よりも高い耐食性を有する金属（つまり、イオン化傾向が小さい、あるいは標準電極電位が高い金属）よりなる基材被覆層１１を基材１０の表面に設けることで、基材１０の銅－亜鉛系合金が外部の環境に露出されなくなるので、外部環境との接触によって基材１０が腐食を受けるのが防止されるようになる。つまり、基材被覆層１１が基材１０の耐食性の低さを補うことにより、プレスフィット端子２を構成する端子材料１全体として、高い耐食性を達成することができる。このように、基材１０の耐食性を補うことができる基材被覆層１１の構成材料として、銅、または基材１０よりも高い耐食性を有する銅合金、ニッケルまたはニッケル合金等を挙げることができる。 As a material characteristic of the base material 10 to be supplemented by the base material coating layer 11, corrosion resistance (stress corrosion cracking) can be exemplified. As described above, in the copper-zinc alloy constituting the base material 10, by limiting the zinc content to 35% by mass or less, relatively high corrosion resistance can be obtained, for example, press fit in the atmosphere. The minimum corrosion resistance necessary for using the terminal 2 can be ensured. However, copper-zinc alloys are inferior in corrosion resistance as compared to copper and various copper alloys that have conventionally been used to form press-fit terminals. Therefore, a base material coating layer 11 made of a metal having higher corrosion resistance than the copper-zinc alloy constituting the base material 10 (that is, a metal having a low ionization tendency or a high standard electrode potential) is formed on the surface of the base material 10. By providing, the copper-zinc alloy of the base material 10 is not exposed to the external environment, so that the base material 10 is prevented from being corroded by contact with the external environment. That is, when the base material coating layer 11 compensates for the low corrosion resistance of the base material 10, high corrosion resistance can be achieved as the entire terminal material 1 constituting the press-fit terminal 2. Thus, as a constituent material of the base material coating layer 11 that can supplement the corrosion resistance of the base material 10, copper, a copper alloy having higher corrosion resistance than the base material 10, nickel, a nickel alloy, or the like can be given.
　基材被覆層１１によって補うべき基材１０の材料特性の別の例として、耐熱性を挙げることができる。プレスフィット端子２は、外部環境や通電による加熱を受けて高温の条件で使用される場合も多いが、この場合に、基材１０を被覆する金属層の表面に向かって、基材１０からの銅原子や亜鉛原子の拡散が起こりやすい。銅原子や亜鉛原子が端子材料１の最表面で酸化されると、電気接続部２０，２５における接触抵抗の上昇等、悪影響を及ぼす可能性がある。そこで、高温での銅原子や亜鉛原子の拡散を抑えるという意味での耐熱性を基材１０に付与できる基材被覆層１１を、基材１０の表面に設けることで、高温での基材１０からの銅原子や亜鉛原子の拡散およびそれに伴う悪影響を低減することができる。このように、基材１０に耐熱性を付与することができる基材被覆層１１の構成材料として、ニッケルまたはニッケル合金、銅または銅合金等を挙げることができる。 As another example of the material characteristics of the base material 10 to be supplemented by the base material coating layer 11, heat resistance can be mentioned. In many cases, the press-fit terminal 2 is used under a high temperature condition by being heated by an external environment or energization. In this case, the press-fit terminal 2 from the base material 10 toward the surface of the metal layer covering the base material 10 Diffusion of copper and zinc atoms is likely to occur. When copper atoms and zinc atoms are oxidized on the outermost surface of the terminal material 1, there is a possibility that adverse effects such as an increase in contact resistance at the electrical connection portions 20 and 25 may occur. Then, the base material 10 at high temperature is provided by providing the base material coating layer 11 on the surface of the base material 10 that can impart heat resistance to the base material 10 in the sense of suppressing diffusion of copper atoms and zinc atoms at high temperature. The diffusion of copper atoms and zinc atoms and the adverse effects associated therewith can be reduced. Thus, nickel or a nickel alloy, copper, a copper alloy, etc. can be mentioned as a constituent material of the base material coating layer 11 which can provide heat resistance to the base material 10. FIG.
　上記のように、基材被覆層１１は複数の金属層より構成してもよい。例えば、同じ特性を付与することができる金属層を複数積層して基材被覆層１１を構成することで、その特性を一層高めて、基材１０に付与することができる。一方、異なる特性を基材１０に付与することができる金属層を複数積層して基材被覆層１１を構成することで、複数の特性を基材１０に付与することができる。また、基材被覆層１１の複数の構成層の全てが端子材料１に積極的に特性を付与しうるものである必要はなく、少なくとも一部が特性の付与に寄与できるものであればよい。例えば、積極的に特性を付与しうる金属層と基材１０との間、あるいは表面層１２との間に、その金属層と基材１０との間、あるいは表面層１２との間の密着性を高めること等を目的として、別の金属層を設けることができる。 As described above, the base material coating layer 11 may be composed of a plurality of metal layers. For example, by forming a base material covering layer 11 by laminating a plurality of metal layers that can impart the same properties, the properties can be further enhanced and imparted to the base material 10. On the other hand, a plurality of properties can be imparted to the substrate 10 by laminating a plurality of metal layers that can impart different properties to the substrate 10 to form the substrate coating layer 11. Further, it is not necessary that all of the plurality of constituent layers of the base material coating layer 11 can positively impart characteristics to the terminal material 1, as long as at least a part can contribute to the provision of characteristics. For example, adhesion between the metal layer and the base material 10 that can positively impart characteristics, or between the surface layer 12, between the metal layer and the base material 10, or between the surface layer 12. Another metal layer can be provided for the purpose of increasing the thickness.
　基材被覆層１１は、プレスフィット端子２を構成する基材１０の全表面に設けられても、例えば電気接続部（基板接続部２０および端子接続部２５）の表面等、一部の部位の表面にのみ設けられてもよい。特に基材被覆層１１が基材１０の耐食性を補うものである場合には、プレスフィット端子２全体の腐食を防止する観点から、プレスフィット端子２を構成する基材１０の全表面に設けることが好ましい。 Even if the base material coating layer 11 is provided on the entire surface of the base material 10 constituting the press-fit terminal 2, for example, the surface of the electrical connection part (the substrate connection part 20 and the terminal connection part 25), etc. It may be provided only on the surface. In particular, when the base material coating layer 11 supplements the corrosion resistance of the base material 10, it is provided on the entire surface of the base material 10 constituting the press-fit terminal 2 from the viewpoint of preventing corrosion of the entire press-fit terminal 2. Is preferred.
（表面層の構成材料）
　上記のように、表面層１２は、基材被覆層１１の表面を被覆して端子材料１の最表面に露出され、端子材料１の表面の特性を制御、調整するものである。 (Constituent material of surface layer)
As described above, the surface layer 12 covers the surface of the base material coating layer 11 and is exposed on the outermost surface of the terminal material 1, and controls and adjusts the surface characteristics of the terminal material 1.
　表面層１２の例として、電気接続部２０，２５の接続信頼性を向上させることができる金属層を挙げることができる。そのような表面層１２としては、スズまたはスズ合金よりなるものを挙げることができる。スズは高い導電率と低い硬度を有し、また表面に形成される酸化膜も破壊されやすいので、電気接続部２０，２５の最表面に露出されることで、低い接触抵抗を示し、高い接続信頼性を与えることができる。特に、スズまたはスズ合金よりなる表面層１２の厚さを０．１μｍ以上としておけば、接続信頼性向上の効果に優れる。一方、その厚さを１．５μｍ以下、さらには１．０μｍ以下としておけば、過剰に表面層１２を厚くすることなく、接続信頼性の向上を十分に達成することができるとともに、軟らかいスズの摩耗による表面層１２の削れを防止しやすくなる。 As an example of the surface layer 12, a metal layer that can improve the connection reliability of the electrical connection portions 20 and 25 can be exemplified. Examples of such a surface layer 12 include those made of tin or a tin alloy. Tin has high electrical conductivity and low hardness, and the oxide film formed on the surface is easily destroyed. Therefore, it is exposed to the outermost surface of the electrical connection portions 20 and 25, thereby exhibiting low contact resistance and high connection. Reliability can be given. In particular, if the thickness of the surface layer 12 made of tin or tin alloy is 0.1 μm or more, the effect of improving the connection reliability is excellent. On the other hand, if the thickness is set to 1.5 μm or less, further 1.0 μm or less, the connection reliability can be sufficiently improved without excessively thickening the surface layer 12, and soft tin It becomes easy to prevent the surface layer 12 from being scraped by abrasion.
（基材被覆層の具体例１：ニッケルまたはニッケル合金よりなる場合）
　ここで、具体例として、基材被覆層１１がニッケルまたはニッケル合金よりなるニッケル被覆層１１ａである場合について詳細に説明する。 (Specific example of substrate coating layer 1: Case of nickel or nickel alloy)
Here, as a specific example, the case where the substrate coating layer 11 is a nickel coating layer 11a made of nickel or a nickel alloy will be described in detail.
　ニッケル被覆層１１ａは、不可避的不純物を除いてニッケルのみよりなっても、ニッケルを主成分とし、他の元素を含むニッケル合金よりなってもよい。ニッケル被覆層１１ａは、図４（ａ）のように、端子材料１の最表面に露出されていてもよいが、図４（ｂ）のように、スズまたはスズ合金よりなる表面層１２に表面を被覆されている方が好ましい。 The nickel coating layer 11a may be made of only nickel except for inevitable impurities, or may be made of a nickel alloy containing nickel as a main component and containing other elements. The nickel coating layer 11a may be exposed on the outermost surface of the terminal material 1 as shown in FIG. 4A, but the surface of the nickel coating layer 11a is formed on the surface layer 12 made of tin or a tin alloy as shown in FIG. Is preferably coated.
　ニッケル被覆層１１ａは、多くの銅－亜鉛系合金より高い耐食性を示し、基材１０の耐食性を補う役割を果たしうる。加えて、ニッケルおよびニッケル合金は、銅原子の拡散を阻止することができる。よって、基材１０の表面にニッケル被覆層１１ａを設けることで、端子材料１の表面（ニッケル被覆層１１ａ自体の表面あるいは表面層１２の表面）に、基材１０を構成する銅原子が拡散するのを抑制することができる。端子材料１が高温に加熱された際に、銅原子が端子材料１の最表面にまで拡散して酸化を受ければ、電気接続部２０，２５の接触抵抗を上昇させる可能性があるが、ニッケル被覆層１１ａが銅原子の拡散を阻止することで、そのような現象を抑制し、端子材料１に耐熱性を付与することができる。銅原子の拡散を十分に防止する観点から、ニッケル被覆層１１ａの厚さは、０．３μｍ以上であることが好ましい。 The nickel coating layer 11a exhibits higher corrosion resistance than many copper-zinc alloys, and can serve to supplement the corrosion resistance of the substrate 10. In addition, nickel and nickel alloys can prevent the diffusion of copper atoms. Therefore, by providing the nickel coating layer 11a on the surface of the base material 10, the copper atoms constituting the base material 10 diffuse on the surface of the terminal material 1 (the surface of the nickel coating layer 11a itself or the surface of the surface layer 12). Can be suppressed. When the terminal material 1 is heated to a high temperature, if copper atoms diffuse to the outermost surface of the terminal material 1 and undergo oxidation, there is a possibility that the contact resistance of the electrical connection portions 20 and 25 may be increased. The coating layer 11a prevents the diffusion of copper atoms, thereby suppressing such a phenomenon and imparting heat resistance to the terminal material 1. From the viewpoint of sufficiently preventing the diffusion of copper atoms, the thickness of the nickel coating layer 11a is preferably 0.3 μm or more.
　ニッケルおよびニッケル合金は硬質の金属であり、ニッケル被覆層１１ａを形成したプレスフィット端子２の基板接続部２０を、図２（ｂ）のように基板３のスルーホール３０に圧入した際等、端子材料１に変形が加わると、ニッケル被覆層１１ａが割れる可能性がある。さらに、ニッケル被覆層１１ａが割れた箇所に応力が集中することで、基材１０の割れにまでつながる可能性がある。こうした割れの現象は、ニッケル被覆層１１ａが厚いほど起こりやすくなる。さらにニッケル被覆層１１ａや基材１０の割れは、それらの割れの部分から基材１０が腐食される事態にもつながりうる。そこで、ニッケル被覆層１１ａ自体の割れや、それに伴う基材１０の割れや腐食を防止する観点から、ニッケル被覆層１１ａの厚さは、１．０μｍ未満であることが好ましい。ニッケル被覆層１１ａの厚さは、０．８μｍ以下、さらには０．６μｍ以下であればさらに好ましい。さらに、従来一般にプレスフィット端子に用いられる銅合金よりも強度が低い傾向がある銅－亜鉛系合金を基材１０として用いていることで、基材１０において高い材料強度を確保しようとすると、端子材料１の加工性が低くなりやすいが、ニッケル被覆層１１ａの厚さを１．０μｍ未満に抑えておくことで、端子材料１全体としての加工性を確保しやすくなる。 Nickel and nickel alloy are hard metals, and when the board connection portion 20 of the press-fit terminal 2 on which the nickel coating layer 11a is formed is press-fitted into the through hole 30 of the board 3 as shown in FIG. If the material 1 is deformed, the nickel coating layer 11a may break. Further, the stress concentrates on the location where the nickel coating layer 11a is cracked, which may lead to cracking of the base material 10. Such a phenomenon of cracking is more likely to occur as the nickel coating layer 11a is thicker. Furthermore, the crack of the nickel coating layer 11a and the base material 10 can also lead to a situation where the base material 10 is corroded from those cracked portions. Therefore, from the viewpoint of preventing the crack of the nickel coating layer 11a itself and the accompanying cracking and corrosion of the base material 10, the thickness of the nickel coating layer 11a is preferably less than 1.0 μm. The thickness of the nickel coating layer 11a is more preferably 0.8 μm or less, and even more preferably 0.6 μm or less. Furthermore, by using a copper-zinc-based alloy that tends to have lower strength than the copper alloy generally used for press-fit terminals in the past as the base material 10, when trying to ensure high material strength in the base material 10, the terminal Although the workability of the material 1 tends to be low, the workability of the terminal material 1 as a whole can be easily ensured by keeping the thickness of the nickel coating layer 11a below 1.0 μm.
（基材被覆層の具体例２：銅または銅合金よりなる場合）
　別の具体例として、基材被覆層１１が銅または銅合金よりなる銅被覆層１１ｂである場合について詳細に説明する。 (Specific example 2 of substrate coating layer: When made of copper or copper alloy)
As another specific example, the case where the substrate coating layer 11 is a copper coating layer 11b made of copper or a copper alloy will be described in detail.
　銅被覆層１１ｂは、不可避的不純物を除いて銅のみよりなっても、銅を主成分とし、他の元素を含む銅合金よりなってもよい。ただし、銅合金よりなる場合に、その銅合金としては、基材１０を構成する銅－亜鉛系合金よりも高い耐食性を有するものが選択される。銅被覆層１１ｂは、図４（ａ）のように、端子材料１の最表面に露出されていてもよいが、図４（ｂ）のように、スズまたはスズ合金よりなる表面層１２に表面を被覆されている方が好ましい。 The copper coating layer 11b may be made of only copper except for inevitable impurities, or may be made of copper alloy containing copper as a main component and containing other elements. However, when made of a copper alloy, a copper alloy having higher corrosion resistance than that of the copper-zinc alloy constituting the substrate 10 is selected. The copper coating layer 11b may be exposed on the outermost surface of the terminal material 1 as shown in FIG. 4 (a), but the surface is formed on the surface layer 12 made of tin or a tin alloy as shown in FIG. 4 (b). Is preferably coated.
　銅は銅－亜鉛系合金よりも高い耐食性を示す。よって、銅、あるいは基材１０の銅－亜鉛合金よりも高い耐食性を有する銅合金よりなる銅被覆層１１ｂで基材１０の表面を被覆しておくことで、基材１０に耐食性を付与し、基材１０の腐食を高度に抑制することができる。特に高い耐食性を付与できるという観点から、銅被覆層１１ｂは、銅合金よりも銅よりなることが好ましい。一方、銅被覆層１１ｂとして銅合金を用いる場合には、具体的には、黄銅、高力黄銅、青銅、リン青銅、鉛青銅、アルミニウム青銅、シルジン青銅、ベリリウム銅、クロム銅等を例示することができる。 Copper exhibits higher corrosion resistance than copper-zinc alloys. Therefore, by covering the surface of the substrate 10 with the copper coating layer 11b made of copper or a copper alloy having higher corrosion resistance than the copper-zinc alloy of the substrate 10, the substrate 10 is given corrosion resistance, Corrosion of the substrate 10 can be highly suppressed. From the viewpoint of providing particularly high corrosion resistance, the copper coating layer 11b is preferably made of copper rather than a copper alloy. On the other hand, when a copper alloy is used as the copper coating layer 11b, concrete examples include brass, high-strength brass, bronze, phosphor bronze, lead bronze, aluminum bronze, silgin bronze, beryllium copper, chromium copper, and the like. Can do.
　耐食性付与の効果を十分に得る観点から、銅被覆層１１ｂの厚さは、５μｍ以上であることが好ましい。上記のように、基材１０を構成する銅－亜鉛系合金において、亜鉛含有量を３５質量％以下に制限しておくことで、大気中等、通常の条件での使用に耐えうる、プレスフィット端子２として最低限の耐食性は確保することができるが、厚さ５μｍ以上の銅被覆層１１ｂを用いることで、後の実施例で適用しているアンモニア雰囲気のように、腐食が非常に進行しやすい過酷な条件でも、基材１０の腐食を高度に抑制することができる。また、銅被覆層１１ｂの厚さを５μｍ以上としておくことで、プレスフィット端子２の基板接続部２０を基板３のスルーホール３０に圧入してプレスフィット端子２を弾性変形させた際に、銅被覆層１１ｂの割れ等の損傷を抑制できる。 From the viewpoint of sufficiently obtaining the effect of imparting corrosion resistance, the thickness of the copper coating layer 11b is preferably 5 μm or more. As described above, in the copper-zinc-based alloy constituting the base material 10, the press-fit terminal can withstand use under normal conditions such as in the atmosphere by limiting the zinc content to 35% by mass or less. 2 can ensure the minimum corrosion resistance, but by using the copper coating layer 11b having a thickness of 5 μm or more, corrosion is very likely to proceed as in the ammonia atmosphere applied in the following examples. Even under severe conditions, corrosion of the substrate 10 can be highly suppressed. Further, by setting the thickness of the copper coating layer 11b to 5 μm or more, when the press-fit terminal 2 is elastically deformed by press-fitting the board connecting portion 20 of the press-fit terminal 2 into the through hole 30 of the board 3, Damage such as cracking of the coating layer 11b can be suppressed.
　一方、銅被覆層１１ｂの厚さは、１０μｍ以下であることが好ましい。銅被覆層１１ｂが厚くなりすぎると、基板３のスルーホール３０の内径との比較において、端子材料１全体としての厚さが大きくなりすぎ、スルーホール３０への基板接続部２０の圧入時に、端子材料１に割れが発生しやすくなるからである。 On the other hand, the thickness of the copper coating layer 11b is preferably 10 μm or less. If the copper coating layer 11b becomes too thick, the thickness of the terminal material 1 as a whole becomes too large in comparison with the inner diameter of the through hole 30 of the substrate 3, and the terminal connecting portion 20 is press-fitted into the through hole 30 at the terminal. This is because cracks are likely to occur in the material 1.
　銅被覆層１１ｂは、上記のように、基材１０に耐食性を付与する効果に加え、耐熱性も付与することができる。つまり、高温になった際に、銅－亜鉛合金よりなる基材１０から亜鉛原子が端子材料１の最表面に拡散し、酸化されて接触抵抗を上昇させるのを、銅被覆層１１ｂが抑制することができる。 As described above, the copper coating layer 11b can also impart heat resistance in addition to the effect of imparting corrosion resistance to the base material 10. That is, when the temperature becomes high, the copper coating layer 11b prevents zinc atoms from diffusing from the base material 10 made of a copper-zinc alloy to the outermost surface of the terminal material 1 and being oxidized to increase the contact resistance. be able to.
　なお、ニッケル被覆層１１ａと銅被覆層１１ｂを積層して用いることも考えられる。その場合には、銅被覆層１１ｂの方を基材１０側に配置すればよい。 It should be noted that the nickel coating layer 11a and the copper coating layer 11b may be stacked and used. In that case, the copper coating layer 11b may be disposed on the substrate 10 side.
　以下に本発明の実施例を示す。なお、本発明はこれら実施例によって限定されるものではない。 Examples of the present invention are shown below. In addition, this invention is not limited by these Examples.
［ニッケル被覆層を設ける場合］
　（試料の作製）
　銅－亜鉛合金よりなる基材の表面に、めっきによって、ニッケルよりなるニッケル被覆層、スズよりなる表面層をこの順に形成して、端子材料を準備した。基材中の亜鉛含有量は、２５質量％とした。ニッケル被覆層の厚さは、表１に示すように、０．３～１．０μｍの範囲で変化させた。スズ表面層の厚さは、０．５μｍとした。この端子材料を用いて、図１，２に示したような形状を有するプレスフィット端子の基板接続部を形成した。また、スルーホールの内周面に銅めっきを施した基板を準備した。 [When nickel coating layer is provided]
(Sample preparation)
A terminal material was prepared by forming a nickel coating layer made of nickel and a surface layer made of tin in this order on the surface of a base material made of a copper-zinc alloy by plating. The zinc content in the substrate was 25% by mass. As shown in Table 1, the thickness of the nickel coating layer was changed in the range of 0.3 to 1.0 μm. The thickness of the tin surface layer was 0.5 μm. Using this terminal material, a substrate connection portion of a press-fit terminal having a shape as shown in FIGS. Moreover, the board | substrate which gave the copper plating to the inner peripheral surface of the through hole was prepared.
（ニッケル被覆層の割れの評価）
　上記のように作製した各プレスフィット端子の基板接続部を基板のスルーホールに圧入した。その状態で、プレスフィット端子を光学顕微鏡にて観察し、ニッケル被覆層の割れの有無を評価した。具体的には、図２（ｂ）中に矢印で示すように、スルーホールの端縁のすぐ内側に相当する位置でプレスフィット端子の表面を観察し、ニッケル被覆層に割れが発生しているかどうかを評価した。基材の銅－亜鉛合金の露出が視認される場合に、割れが発生していると判定し（表中「有」）、基材の銅－亜鉛合金の露出が視認されない場合に、割れが発生していないと判定した（表中「無」）。 (Evaluation of cracks in nickel coating layer)
The board connection part of each press-fit terminal produced as described above was press-fitted into the through hole of the board. In this state, the press-fit terminal was observed with an optical microscope, and the presence or absence of cracks in the nickel coating layer was evaluated. Specifically, as indicated by an arrow in FIG. 2B, the surface of the press-fit terminal is observed at a position corresponding to the inner side of the edge of the through hole, and cracks are generated in the nickel coating layer. I evaluated it. When the exposure of the copper-zinc alloy of the base material is visually recognized, it is determined that a crack has occurred ("Yes" in the table), and when the exposure of the copper-zinc alloy of the base material is not visually recognized, the crack is generated. It was determined that it did not occur ("None" in the table).
（試験結果）
　図５に、プレスフィット端子の基板接続部を基板のスルーホールに圧入した状態について、スルーホールの端縁近傍を撮影した写真を示す。また、表１に、ニッケル被覆層の厚さとともに、ニッケル被覆層の割れの有無の評価結果を示す。 (Test results)
FIG. 5 shows a photograph of the vicinity of the edge of the through hole in a state in which the board connecting portion of the press fit terminal is press-fitted into the through hole of the board. Table 1 shows the evaluation results of the presence or absence of cracks in the nickel coating layer together with the thickness of the nickel coating layer.
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　ニッケル被覆層の厚さが１．０μｍである場合の図５（ｄ）においては、図中に矢印で指示するように、プレスフィット端子の角部に、筋状に基材が露出しているのが観察された。つまり、ニッケル被覆層に割れが生じている。これに対し、ニッケル被覆層の厚さがそれよりも薄い図５（ａ）～（ｃ）においては、このような筋状の基材の露出は見られていない。つまり、ニッケル被覆層に割れが生じていない。これらの結果は、表１にもまとめたとおりである。 In FIG. 5D when the thickness of the nickel coating layer is 1.0 μm, the base material is exposed in a streak shape at the corner of the press-fit terminal as indicated by the arrow in the figure. Was observed. That is, the nickel coating layer is cracked. In contrast, in FIGS. 5 (a) to 5 (c) where the thickness of the nickel coating layer is thinner than this, such a streak-like substrate is not exposed. That is, the nickel coating layer is not cracked. These results are also summarized in Table 1.
　このように、ニッケル被覆層の厚さを１．０μｍ未満としておくことで、プレスフィット端子の基板接続部を基板のスルーホールに圧入して端子材料が弾性変形を受けても、ニッケル被覆層の割れを回避できることが確認された。 Thus, by setting the thickness of the nickel coating layer to less than 1.0 μm, even if the terminal material is elastically deformed by press-fitting the board connection portion of the press-fit terminal into the through hole of the board, the nickel coating layer It was confirmed that cracking can be avoided.
［銅被覆層を設ける場合］
（試料の作製）
　銅－亜鉛合金よりなる基材の表面に、めっきによって、銅よりなる銅被覆層、スズよりなる表面層をこの順に形成して、端子材料を準備した。基材中の亜鉛含有量および銅被覆層の厚さは、表２に示すように変化させた。スズ表面層の厚さは、１μｍとした。この端子材料を用いて、上記ニッケル被覆層を設けた場合の試験と同様のプレスフィット端子を形成した。また、同様のスルーホールを有する基板を準備した。 [When providing a copper coating layer]
(Sample preparation)
A terminal material was prepared by forming a copper coating layer made of copper and a surface layer made of tin in this order on the surface of a base material made of a copper-zinc alloy by plating. The zinc content in the substrate and the thickness of the copper coating layer were changed as shown in Table 2. The thickness of the tin surface layer was 1 μm. Using this terminal material, a press-fit terminal similar to the test in the case where the nickel coating layer was provided was formed. Moreover, the board | substrate which has the same through hole was prepared.
（応力腐食割れの評価）
　上記のように作製した各プレスフィット端子の基板接続部を基板のスルーホールに圧入した。その状態で、プレスフィット端子をアンモニア雰囲気中に放置した（１４％アンモニア水使用、４時間、温度：２５℃）、その後、プレスフィット端子を光学顕微鏡にて観察し、銅被覆層の割れの有無を評価した。具体的には、図２（ｂ）中に矢印で示すように、スルーホールの端縁のすぐ内側に相当する位置でプレスフィット端子の表面を観察し、基材に応力腐食割れが発生しているかどうかを評価した。評価においては、基材の割れが視認されるかどうかを基準に、大きな応力腐食割れが発生している（表中「×」）、軽微な応力腐食割れが発生している（表中「△」）、応力腐食割れが発生していない（表中「○」）のいずれであるかを判定した。 (Evaluation of stress corrosion cracking)
The board connection part of each press-fit terminal produced as described above was press-fitted into the through hole of the board. In this state, the press-fit terminal was left in an ammonia atmosphere (using 14% ammonia water, 4 hours, temperature: 25 ° C.). Thereafter, the press-fit terminal was observed with an optical microscope to check for cracks in the copper coating layer. Evaluated. Specifically, as indicated by an arrow in FIG. 2B, the surface of the press-fit terminal is observed at a position corresponding to the inner side of the edge of the through hole, and stress corrosion cracking occurs in the base material. Evaluated whether or not. In the evaluation, on the basis of whether or not the crack of the base material is visually recognized, a large stress corrosion crack occurs ("X" in the table), and a slight stress corrosion crack occurs ("△" in the table). ]) And stress corrosion cracking did not occur ("○" in the table).
（試験結果）
　表２に、基材中の亜鉛含有量および銅被覆層の厚さとともに、応力腐食割れの評価結果を示す。 (Test results)
Table 2 shows the evaluation results of stress corrosion cracking together with the zinc content in the substrate and the thickness of the copper coating layer.
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示されるように、基材の亜鉛含有量を３５質量％以下としておき、さらに銅被覆層の厚さを５μｍ以上とすることで、アンモニア雰囲気中のような非常に腐食が起こりやすい環境でも、基材の応力腐食割れを防止することが可能となっている。つまり、厚さ５μｍ以上の銅被覆層によって、亜鉛含有量３５質量％以下の銅－亜鉛合金よりなる基材に高い耐食性を付与することができる。 As shown in Table 2, by setting the zinc content of the base material to 35% by mass or less and further setting the thickness of the copper coating layer to 5 μm or more, an environment that is very susceptible to corrosion such as in an ammonia atmosphere. However, it is possible to prevent stress corrosion cracking of the substrate. That is, high corrosion resistance can be imparted to a substrate made of a copper-zinc alloy having a zinc content of 35% by mass or less by a copper coating layer having a thickness of 5 μm or more.
　以上、本発明の実施の形態について詳細に説明したが、本発明は上記実施の形態に何ら限定されるものではなく、本発明の要旨を逸脱しない範囲で種々の改変が可能である。 The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.
１　　　　　端子材料
１１　　　　基材被覆層
１１ａ　　　ニッケル被覆層
１１ｂ　　　銅被覆層
１２　　　　表面層
２　　　　　プレスフィット端子
２０　　　　基板接続部
２１　　　　膨出片
２１ａ　　　接点部
２５　　　　端子接続部
４　　　　　基板用コネクタ DESCRIPTION OF SYMBOLS 1 Terminal material 11 Base material coating layer 11a Nickel coating layer 11b Copper coating layer 12 Surface layer 2 Press fit terminal 20 Board connection part 21 Swelling piece 21a Contact part 25 Terminal connection part 4 Board connector

Claims (10)

  1. 　基材と、
    　前記基材と異なる金属種よりなり、前記基材の表面を被覆する基材被覆層と、
    を有するプレスフィット端子において、
    　前記基材が、亜鉛含有量が３５質量％以下である銅－亜鉛系合金よりなることを特徴とするプレスフィット端子。     A substrate;
    A base material coating layer comprising a metal species different from the base material and covering the surface of the base material;
    In press-fit terminals having
    A press-fit terminal, wherein the substrate is made of a copper-zinc alloy having a zinc content of 35% by mass or less.
  2. 　前記基材被覆層は、前記基材よりも耐食性の高い金属よりなる層を有することを特徴とする請求項１に記載のプレスフィット端子。 The press-fit terminal according to claim 1, wherein the base material coating layer has a layer made of a metal having higher corrosion resistance than the base material.
  3. 　前記基材被覆層は、厚さ１．０μｍ未満のニッケルまたはニッケル合金よりなるニッケル被覆層を有することを特徴とする請求項１または２に記載のプレスフィット端子。 The press-fit terminal according to claim 1 or 2, wherein the substrate coating layer has a nickel coating layer made of nickel or a nickel alloy having a thickness of less than 1.0 µm.
  4. 　前記ニッケル被覆層の厚さは、０．３μｍ以上であることを特徴とする請求項３に記載のプレスフィット端子。 The press-fit terminal according to claim 3, wherein the nickel coating layer has a thickness of 0.3 µm or more.
  5. 　前記基材被覆層は、銅、または前記基材よりも耐食性の高い銅合金よりなる、厚さ５μｍ以上の銅被覆層を有することを特徴とする１から４のいずれか１項に記載のプレスフィット端子。 The press according to any one of claims 1 to 4, wherein the base material coating layer has a copper coating layer having a thickness of 5 µm or more and made of copper or a copper alloy having higher corrosion resistance than the base material. Fit terminal.
  6. 　前記銅被覆層は銅よりなることを特徴とする請求項５に記載のプレスフィット端子。 The press-fit terminal according to claim 5, wherein the copper coating layer is made of copper.
  7. 　前記銅被覆層の厚さは、１０μｍ以下であることを特徴とする請求項５または６に記載のプレスフィット端子。 The press-fit terminal according to claim 5 or 6, wherein the copper coating layer has a thickness of 10 µm or less.
  8. 　前記プレスフィット端子の少なくとも電気接続部において前記基材被覆層の表面を被覆して、最表面に露出したスズまたはスズ合金よりなる表面層を有することを特徴とする請求項１から７のいずれか１項に記載のプレスフィット端子。 The surface layer made of tin or a tin alloy, which covers the surface of the base material coating layer at least at the electrical connection portion of the press-fit terminal and is exposed on the outermost surface, is provided. The press-fit terminal according to item 1.
  9. 　前記表面層の厚さは、０．１μｍ以上、１．５μｍ以下であることを特徴とする請求項８に記載のプレスフィット端子。 The press-fit terminal according to claim 8, wherein the thickness of the surface layer is 0.1 µm or more and 1.5 µm or less.
  10. 　請求項１から９のいずれか１項に記載のプレスフィット端子を備えることを特徴とする基板用コネクタ。 A board connector comprising the press-fit terminal according to any one of claims 1 to 9.
PCT/JP2017/030434 2016-08-31 2017-08-25 Press-fit terminal and substrate connector WO2018043308A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2016-169862 2016-08-31
JP2016169862A JP2018037301A (en) 2016-08-31 2016-08-31 Press-fit terminal and connector for substrate

Publications (1)

Publication Number Publication Date
WO2018043308A1 true WO2018043308A1 (en) 2018-03-08

Family

ID=61300801

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2017/030434 WO2018043308A1 (en) 2016-08-31 2017-08-25 Press-fit terminal and substrate connector

Country Status (2)

Country Link
JP (1) JP2018037301A (en)
WO (1) WO2018043308A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024068765A1 (en) * 2022-09-28 2024-04-04 Robert Bosch Gmbh Connection arrangement and method for forming a connection arrangement

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012190603A (en) * 2011-03-09 2012-10-04 Sumitomo Wiring Syst Ltd Terminal fitting
JP2015045052A (en) * 2013-08-27 2015-03-12 Jx日鉱日石金属株式会社 Electronic-component metallic material and method for producing the same, and connector terminal, connector and electronic component using the same

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012190603A (en) * 2011-03-09 2012-10-04 Sumitomo Wiring Syst Ltd Terminal fitting
JP2015045052A (en) * 2013-08-27 2015-03-12 Jx日鉱日石金属株式会社 Electronic-component metallic material and method for producing the same, and connector terminal, connector and electronic component using the same

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2024068765A1 (en) * 2022-09-28 2024-04-04 Robert Bosch Gmbh Connection arrangement and method for forming a connection arrangement

Also Published As

Publication number Publication date
JP2018037301A (en) 2018-03-08

Similar Documents

Publication Publication Date Title
JP6183543B2 (en) Terminal pair and connector pair with terminal pair
WO2013140850A1 (en) Metallic material for electronic component, connector terminal obtained using same, connector, and electronic component
JP2008223143A (en) Plated material and method for preparation thereof, and electric and electronic parts using the same
WO2017154496A1 (en) Electrical contact and connector terminal pair
WO2015068572A1 (en) Substrate terminal and substrate connector
TW495769B (en) Electrically conductive metal band and plug connection
KR102011186B1 (en) Metal material for use in electronic component, and method for producing same
US9954297B2 (en) Terminal fitting and connector
WO2018043308A1 (en) Press-fit terminal and substrate connector
WO2016006469A1 (en) Press-fit terminal and board connector
WO2017077856A1 (en) Terminal fitting and connector
US20170162969A1 (en) Terminal pair and connector
JP4260826B2 (en) Connector parts
JP6553333B2 (en) Metal material for electronic parts, connector terminal using the same, connector and electronic parts
CN109715864B (en) Conductive strip
JP4356417B2 (en) Copper alloy wire for electronic parts
CN109845041B (en) Connection terminal and method for manufacturing connection terminal
WO2020153396A1 (en) Connector terminal material and connector terminal
WO2018079253A1 (en) Electrical contact, connector terminal pair, and connector pair
JP2005105419A (en) Plated material, method of producing the same, and electrical/electronic part using the same
JP5748019B1 (en) Pin terminals and terminal materials
JP2007204854A (en) Plated material, method of producing the same, and electrical/electronic part using the same
JP2015167099A (en) Connector terminal and manufacturing method of the same
JP3628836B2 (en) Sn or Sn alloy plated copper alloy material
WO2020149401A1 (en) Metallic material and connecting terminal

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 17846313

Country of ref document: EP

Kind code of ref document: A1

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 17846313

Country of ref document: EP

Kind code of ref document: A1