JP5782298B2 - Oblique winding spring and wire for oblique winding spring - Google Patents

Description

  The present invention relates to an oblique winding spring used for a contact member for connector connection and the like, and an oblique winding spring wire used for a material of the oblique winding spring. In particular, the present invention relates to a slant winding spring that is excellent in both spring characteristics and conductivity, and a slant winding spring wire suitable for the material of the spring.

  As a structure for electrically connecting various electric devices and electric wires, a connector connection in which a terminal provided at an end portion of the electric wire is inserted into a connector portion provided in the electric device is conventionally used. Further, an oblique winding spring (tilted coil spring) is used as a multi-contact member for sufficiently maintaining the contact state between the connector portion and the terminal (see, for example, Patent Document 1). The slant winding spring is a tilt coil spring whose pitch angle changes periodically. The spring with this structure applies a load to the peripheral surface and compresses each coil as it tilts with respect to the coil axis. Thus, for example, it functions as a contact. By interposing this slanted winding spring between the connector part and the terminal and applying a spring load (spring biasing force) to both the connector part and the terminal, the contact state between the connector part and the terminal is sufficient. Can be maintained.

  The contact member is desired to have high conductivity. Therefore, copper is conventionally used as a material for the above-described oblique winding spring as described in Patent Document 1.

  However, since copper has low strength, copper slant winding springs tend to sag by repeated insertion / removal operations of terminals (easily plastically deformed). For this reason, with a copper diagonal spring, the spring load required for the displacement (increase) of the spring height when the spring is compressed in a direction perpendicular to the axial direction cannot be obtained, and the diagonal winding A non-linear region of spring load, which is a characteristic of the spring, cannot be obtained. The non-linear region refers to a displacement region where the spring load is constant and sufficiently large regardless of the amount of displacement. Accordingly, beryllium copper having high strength and high electrical conductivity is used as the material of the above-described oblique winding spring when it is desired that the spring characteristics (load, nonlinearity) are also excellent.

JP 2008-176965 A

  However, beryllium (Be) is harmful to the human body and it is desirable to reduce its use. Therefore, it is desired to develop an obliquely wound spring having a conductivity equivalent to or equal to or equal to that of beryllium copper and having excellent spring characteristics without using beryllium copper as a material, and its material.

  Then, one of the objectives of this invention is providing the wire for diagonal winding springs from which the diagonal winding spring excellent in a spring characteristic and electroconductivity is obtained. Another object of the present invention is to provide a diagonally wound spring having excellent spring characteristics and conductivity.

  The inventors of the present invention have two characteristics required for an oblique winding spring used for a contact member, that is, excellent conductivity and difficult to sag (typically a large spring load and a large non-linear region). We studied various configurations that satisfy these two characteristics. As a result, since it is difficult to improve the spring characteristics when the constituent material of the slant winding spring is made of a single material, it has been considered to configure it with a plurality of different materials. Specifically, a composite wire comprising a core wire and an outer layer covering the outer periphery of the core wire using a material having high conductivity and a high-strength material was examined. And in the slant winding spring used for the contact member for connector connection, (1) the outer layer is made of a material having excellent conductivity, and (2) the hardness difference between the core wire and the outer layer is sufficiently large. And obtained the knowledge that it is preferable.

  Based on the above findings, the present invention defines that the constituent materials of the core wire and the outer layer satisfy a specific hardness difference, and that the outer layer is made of a material having excellent conductivity.

  The wire for an oblique winding spring of the present invention is a wire used as a material for an oblique winding spring, and is composed of a composite wire comprising a core wire and an outer layer provided on the outer periphery of the core wire. The core wire is made of austenitic stainless steel, and the outer layer is made of one kind of metal selected from copper, copper alloy, aluminum, and aluminum alloy. The difference in Vickers hardness Hv between the core wire and the outer layer is 350 or more.

  By using the wire for an oblique winding spring of the present invention, the oblique winding spring of the present invention can be manufactured. The diagonally wound spring of the present invention is composed of a composite wire comprising a core wire and an outer layer provided on the outer periphery of the core wire. The core wire is made of austenitic stainless steel, and the outer layer is made of one kind of metal selected from copper, copper alloy, aluminum, and aluminum alloy. The difference in Vickers hardness Hv between the core wire and the outer layer is 350 or more.

  When the slant winding spring of the present invention is used as a contact member for connector connection, the outer layer made of a material having excellent conductivity is in direct contact with both the connector portion and the terminal, so that sufficient conduction can be ensured. That is, the oblique winding spring of the present invention can reduce the contact resistance when used as the contact member as compared with the case where the outer layer is made of stainless steel having a lower conductivity than copper or the like. Moreover, the diagonally wound spring of the present invention is easily deformed because the hardness difference between the core wire and the outer layer is sufficiently large and the outer layer has a relatively low hardness. Therefore, when the diagonally wound spring of the present invention is used as a contact member, the outer layer can be sufficiently deformed and can sufficiently contact both the connector portion and the terminal by deformation. Since contact resistance can be reduced also from this point, the slant winding spring of this invention is excellent in electroconductivity by reduction of contact resistance.

  And the diagonal winding spring of this invention can achieve the high intensity | strength of the whole spring because a core wire is comparatively enough high hardness. Therefore, the diagonally wound spring of the present invention can obtain a sufficient spring load, has a large non-linear region, and is excellent in non-linearity. For this reason, when the diagonally wound spring of the present invention is used for a contact member, it is difficult to sag even if the terminal is repeatedly inserted and removed, and the reliability of the contact member can be improved. In addition, due to the excellent non-linearity, the slant winding spring of the present invention has variations in spring dimensions due to manufacturing errors, and when used as a contact member, it varies in the height of the spring compressed in the direction perpendicular to the axial direction of the spring. Even if there is, there is a large non-linear region, so that a predetermined spring load can be applied to both the connector part and the terminal regardless of the height of the spring. That is, the slant winding spring of the present invention can absorb manufacturing errors, and the reliability of the contact member can be improved even when the spring height does not change due to repeated insertion and removal of the terminals.

  The wire for an oblique winding spring of the present invention can provide an oblique winding spring that is excellent in conductivity and excellent in non-linearity.

  As mentioned above, it is a composite wire rod with a specific stacking order, and the inner and outer materials are specified materials, ensuring good conductivity by reducing contact resistance, and ensuring good spring characteristics by having a high-strength material. To achieve both, it can be said that the difference in hardness between the inside and outside of the composite wire can be used as an index. Therefore, in the present invention, the difference in Vickers hardness Hv is defined.

  As an embodiment of the present invention, the austenitic stainless steel may include an embodiment satisfying at least one of C: 0.05% to 0.1% and N: 0.1% to 0.3% by mass%.

  The stainless steel is excellent in strength because it contains a large amount of carbon (C) and nitrogen (N). Moreover, since the core wire is made of high-strength stainless steel, for example, the core wire can be made thin, that is, the proportion of the outer layer can be relatively increased. From these facts, the above-described form including the core wire made of stainless steel provides an oblique winding spring that is excellent in both spring characteristics and conductivity. Alternatively, the slanted winding spring can be reduced in size (thinner diameter) by making the core wire thinner.

  As one form of this invention, the form whose area ratio of the outer side layer with respect to the cross section of the said composite wire is 30% or more and 90% or less is mentioned.

  In the above aspect, the ratio of the outer layer is sufficiently high, the conductivity is excellent, and the high-strength core wire is also sufficiently present, so that an oblique spring having both excellent spring characteristics and conductivity can be obtained.

  As one form of this invention, the form whose difference of the Vickers hardness Hv of the said core wire and the said outer layer is 400 or more is mentioned.

  In the above-mentioned form, the core wire has a higher hardness and the outer layer is made of a material having a relatively low hardness, for example, a material having a high conductivity such as annealed copper. A superior oblique winding spring is obtained.

  As an embodiment of the present invention, the austenitic stainless steel satisfies at least one of C: 0.05% to 0.1% and N: 0.1% to 0.3% by mass%, and Si: 0.3% to 2.0%. , Mn: 0.5% or more and 4.0% or less, Cr: 16% or more and 20% or less, Ni: 6.0% or more and 14.0% or less, with the balance being Fe and inevitable impurities.

  The stainless steel has high strength as described above due to the high concentration of carbon (C) and nitrogen (N). Moreover, since the core wire can be thinned by increasing the strength of the core wire as described above, the outer layer can be increased. From these things, the said form can obtain the diagonal winding spring which is excellent in both a spring characteristic and electroconductivity. Alternatively, the slanted winding spring can be reduced in size (thinner diameter) by making the core wire thinner.

  As the austenitic stainless steel, one or two kinds selected from Mo: 0.1% to 4.0%, Nb: 0.1% to 2.0%, and Ti: 0.1% to 2.0% in mass%. The form containing an element is mentioned.

  The stainless steel has higher strength by adding Mo, Nb, and Ti. Moreover, since the core wire can be thinned by increasing the strength of the core wire as described above, the outer layer can be increased. From these things, the said form can obtain the diagonally wound spring which is more excellent in both spring characteristics and conductivity. Alternatively, the slanted winding spring can be reduced in size (thinner diameter) by making the core wire thinner.

  The diagonally wound spring of the present invention is excellent in both spring characteristics and conductivity. The wire for oblique winding springs of the present invention provides an oblique winding spring that is excellent in both spring characteristics and conductivity.

FIG. 1 (A) is a cross-sectional view of the wire for an oblique winding spring according to the embodiment, and FIG. 1 (B) is a front view and a side view of the oblique winding spring according to the embodiment. FIG. 2 is an explanatory diagram for explaining a method for measuring the nonlinearity of the obliquely wound spring. FIG. 3 is a graph showing the relationship between the displacement of the spring height and the spring load. FIG. 4 is an explanatory diagram for explaining a method of measuring the electrical resistivity of the oblique winding spring. FIG. 5 is an explanatory diagram for explaining a method of measuring electrical resistivity assuming a case where an oblique winding spring is used as a contact member, FIG. 5 (A) is a side view, and FIG. 5 (B) is a front view. . FIG. 6 is a graph showing the relationship between the energization time and the temperature rise when energizing the oblique winding spring produced in Test Example 1. FIG. 7 is a graph showing the relationship between the energization time and the temperature rise when energizing the oblique winding spring produced in Test Example 2. FIG. 8 is a graph showing the relationship between the energization time and the temperature rise when energizing the slant winding spring produced in Test Example 3. FIG. 9 is a graph showing the relationship between the energization time and the temperature rise when energizing the slant winding spring produced in Test Example 4. FIG. 10 is a schematic explanatory view showing an example of use in which a diagonally wound spring is used as a contact member.

The present invention will be described in detail below.
In the following description, the contents of “composition” are all “mass%”.

[Composite wire]
(Core wire)
The core wire mainly contributes to ensuring the spring characteristics of the composite wire. The constituent material of this core wire is an iron-based alloy containing carbon (C), that is, steel, further containing chromium (Cr) and nickel (Ni), and stainless steel having an austenitic structure (γ structure). . Typically, it is a stainless steel containing C, Cr, Ni, manganese (Mn), silicon (Si), the balance being Fe and inevitable impurities, for example, 18Cr-8Ni stainless steel. In particular, in the present invention, this γ-based stainless steel has a composition satisfying a Vickers hardness Hv difference of 350 or more with an outer layer described later. As such a composition, for example, a general-purpose steel type: SUS304 can be used.

  In particular, γ-based stainless steel having a high content of C and nitrogen (N) tends to have a large Vickers hardness (absolute value), and the hardness difference can be sufficiently large. Specifically, it is preferable to satisfy at least one of C: 0.05% or more and N: 0.1% or more, and it is more preferable to satisfy both.

  C is a strong austenite-forming element, and can be strengthened by introducing strain and strengthening by fixing dislocations. Moreover, hardness and intensity | strength can further be improved by heat processing. As the amount of C increases, the hardness and strength can be increased. However, when the amount is too large, Cr carbide is easily generated, and the lack of Cr causes a decrease in toughness and a decrease in corrosion resistance. Accordingly, the C content is preferably 0.1% or less, more preferably 0.06% or more and 0.08% or less.

  N is also a strong austenite-forming element and has a dislocation fixing effect. The more N, the higher the hardness and strength. However, if N is too much, it causes blowholes during melting and casting, so 0.3% or less is preferable. A more preferable content of N is 0.15% or more and 0.25% or less.

  As a more specific composition, for example, at least one of C: 0.05% to 0.1% and N: 0.1% to 0.3% is satisfied, Si: 0.3% to 2.0%, Mn: 0.5% to 4.0%, Cr: 16% -20%, Ni: 6.0% to 14.0%, with the balance being Fe and inevitable impurities. Furthermore, the form containing 1 type or 2 types of elements selected from Mo: 0.1% -4.0%, Nb: 0.1% -2.0%, and Ti: 0.1% -2.0% is mentioned.

  Cr is a main constituent element of γ stainless steel and contributes to heat resistance, oxidation resistance, and the like. Considering the stability of the γ phase, it is preferably 16% or more, and considering the deterioration of toughness, it is preferably 20% or less. A more preferable content of Cr is 17.0% or more and 19.0% or less.

  Ni is an element that is effective in stabilizing the γ phase. Considering the stability of the γ phase, it is preferably 6.0% or more, and if a relatively large amount of N is included, blow holes are likely to occur. Therefore, 14.0% or less is preferable. A more preferable content of Ni is 8.0% or more and 11.0% or less.

  Si acts as a deoxidizer during melting and refining. In order to obtain the effect as a deoxidizer, the Si content is preferably 0.3% or more. The more Si, the better the strength and corrosion resistance can be expected, but there is concern about the deterioration of toughness. Considering toughness deterioration, 2.0% or less is preferable. A more preferable content of Si is 0.4% or more and 1.2% or less.

  Mn is used as a deoxidizing agent during melting and refining in the same way as Si. Mn also contributes to the stabilization of the γ phase, so 0.5% or more is preferable, and 4.0% or less is preferable in consideration of oxidation resistance at high temperatures. A more preferable content of Mn is 1.0% or more and 3.0% or less.

  Any of Mo, Nb, and Ti can be contained in the specific range, so that they can be dissolved in the γ phase to improve the mechanical properties. More preferable contents of each element are Mo: 0.5% to 3.0%, Nb: 0.8% to 1.5%, and Ti: 0.4% to 1.0%.

(Outer layer)
The constituent material of the outer layer is one selected from copper, copper alloy, aluminum, and aluminum alloy, and the Vickers hardness Hv is 350 or less smaller than the above-described γ-based stainless steel constituting the core wire. Since these metals have higher conductivity than the above-described γ-based stainless steel, the outer layer mainly contributes to ensuring the conductivity of the composite wire. Moreover, since these metals are relatively softer than the above-mentioned γ-type stainless steel, they can sufficiently follow the deformation of the raw material wires of the core wire during the production of the composite wire. Furthermore, these metals are relatively soft and can be easily deformed. Therefore, when the slant winding spring manufactured from the wire for slant winding spring of the present invention is used as a contact member, these metals constituting the outer layer are sufficiently deformed by the pressing force at the time of inserting the terminal, and the connector portion And a sufficient contact area with both terminals can be secured. Therefore, such an outer layer effectively reduces the contact resistance with the connector portion and the terminal, and an oblique winding spring having excellent conductivity can be obtained.

  The copper includes so-called pure copper having a Cu content of 99.9% or more, typically soft copper (conductivity: 100% IACS). Copper alloys include, for example, phosphor bronze (for example, Sn: 5.5% to 7.0%, P: 0.03% to 0.35%, specifically JIS C5191, etc.), brass (for example, Zn: 38%) One containing ˜41% (specifically, C2801 of JIS standard). Copper and copper alloys have high electrical conductivity and also have a small difference in thermal expansion coefficient and corrosion potential from stainless steel, and are suitable as a constituent material for composite wires with stainless steel. Even when beryllium copper is used as the constituent material of the outer layer, the present invention includes a core wire. Therefore, compared to the case where the whole of the slant winding spring and the slant winding spring wire is made of beryllium copper, beryllium copper. Can be reduced. Therefore, beryllium copper can be used as the copper alloy, but it is preferable not to use it.

  Aluminum is a so-called pure aluminum (JIS standard 1000 series, for example, A1050, A1070, A1085, A1100, etc.) with an Al content of 99.0% or more, and aluminum alloy is, for example, an Al-Cu alloy (JIS standard 2000 series). For example, A2017 etc.), Al-Mg alloys (JIS standard 5000 series, such as A5052, A5083 etc.), Al-Zn-Mg alloys (JIS standard 7000 series, eg A7075 etc.), etc. . Aluminum and aluminum alloys are lightweight, and the weight of the composite wire can be reduced.

(Ratio between core wire and outer layer)
The higher the area ratio of the outer layer in the cross section of the composite wire, the better the conductivity. The higher the area ratio of the core wire, the higher the strength. When the diagonally wound spring manufactured from the diagonally wound spring wire of the present invention is used as a contact member, the area ratio of the outer layer is preferably 30% or more in order to obtain sufficient conductivity. The greater the difference in Vickers hardness Hv between the core wire and the outer layer, the higher the hardness and strength of the core wire, so even if the core wire is thin, sufficient strength can be maintained, so the area ratio of the outer layer Can be increased. However, if the area ratio of the outer layer is too large, the drawability and the spring characteristics of the slant winding spring are deteriorated during the production of the composite wire. Therefore, the area ratio of the outer layer is preferably 90% or less. A more preferable range of the area ratio of the outer layer is 30% or more and 60% or less.

(Wire diameter)
For the composite wire, various wire diameters can be selected so that a desired oblique winding spring can be obtained. In the case of using the material of the slant winding spring used for the contact member for connector connection, the wire diameter is 0.2 mm to 1.2 mm.

(Mechanical properties)
In the present invention, the core wire is characterized in that the Vickers hardness Hv is higher than that of the outer layer, and the difference is 350 or more. As the hardness difference is higher, the absolute value of the Vickers hardness of the core wire is relatively increased and the strength is increased, and a diagonally wound spring having a large non-linear region and excellent conductivity is obtained. Therefore, the hardness difference is preferably as high as possible, and is preferably 380 or more, more preferably 400 or more, and there is no particular upper limit. The absolute value of the Vickers hardness Hv of the core wire is preferably 600 or more, more preferably 650 or more.

(Electrical characteristics)
The wire for an oblique winding spring of the present invention has a high electrical conductivity and can be configured to satisfy 20% IACS or more, depending on the area ratio of the outer layer. The higher the area ratio of the outer layer is, the higher the conductivity is, and it is possible to obtain a form satisfying 50% IACS or more.

[Slant winding spring]
In the composite wire constituting the oblique winding spring of the present invention, the difference in Vickers hardness Hv between the core wire and the outer layer satisfies 350 or more. Therefore, the oblique winding spring of the present invention can be increased in strength compared to the beryllium copper oblique winding spring having the same specifications, so that the spring load is increased, the nonlinear region is increased, Or low resistance. Moreover, as shown in the test example mentioned later, it can be set as a spring with a still larger hardness difference by heat-processing after a spring process.

  The axial length, the major axis, the minor axis, the number of windings, and the like of the oblique winding spring of the present invention can be appropriately selected. The oblique winding spring of the present invention substantially maintains the hardness difference in the wire used for the material (typically, the wire for the oblique winding spring of the present invention) or has a larger hardness difference. Further, the composition of the composite wire constituting the slant winding spring of the present invention, the area ratio of the outer layer, the wire diameter, and the conductivity are the composition of the wire used for the material (typically, the wire of the present invention), the area of the outer layer. The ratio, wire diameter, and conductivity are substantially maintained.

[Production method]
The wire for an oblique winding spring of the present invention is a so-called clad wire manufacturing method, that is, preparation of a raw material wire to be a core wire, preparation of a raw material member to be an outer layer → manufacturing an integrated material of raw material wire and raw material member → integration It can be manufactured through a process of drawing a chemical compound. For the production of raw material wire, a known method of manufacturing a γ-based stainless steel wire can be used. Typically, the raw material wire is manufactured through the steps of melting, hot forging, hot rolling, and wire drawing. can do. A pipe material, a strip-shaped material, or a plate-shaped material can be used for the raw material member of the outer layer. The integrated product can be manufactured, for example, by inserting a raw material wire into a pipe material, wrapping a strip-shaped material around the outer periphery of the raw material wire, or wrapping with a plate-shaped material. A known copper pipe or copper plate, aluminum pipe or aluminum plate manufacturing method can be used for the production of the pipe material, strip material or plate material. The pipe material is typically manufactured through a process of melting → casting → hot extrusion → cold rolling → drawing (drawing, stretching), and plate material is manufactured through a process of melting → casting → hot rolling → cold rolling. be able to. The final wire diameter and strength of the composite wire and the area ratio of the outer layer are the desired values for the wire diameter of the raw material wire, the thickness (outer diameter) of the pipe material, plate-like material, and strip-like material, and the degree of wire drawing It can select suitably so that it may become.

  The raw material wire and the raw material member have a sufficient hardness difference. Therefore, at the time of wire drawing for the above-mentioned compounding, the stress applied by wire drawing hardly occurs at the boundary portion between the raw material wire and the raw material member, and the raw material member is sufficient to follow the raw material wire. Transforms into Therefore, the boundary portion between the core wire and the outer layer does not substantially become a mechanical weak point in the obtained composite wire, and the oblique winding spring of the present invention manufactured using this composite wire is excellent in non-linearity.

  You may heat-process after the wire drawing for the said composite. By performing the heat treatment, the hardness of the γ-based stainless steel containing a large amount of C, N, etc. can be increased, and the hardness difference between the core wire and the outer layer can be further increased. Although depending on the material of the core wire, for example, the hardness difference can be set to 400 or more, further 450 or more, particularly 500 or more, and an oblique winding spring having further excellent spring characteristics can be obtained. On the other hand, since the outer layer is in a state of being subjected to aging treatment by this heat treatment, the conductivity can be further increased. The temperature of this heat treatment is, for example, 400 ° C. or higher and 500 ° C. or lower.

  The diagonal winding spring of the present invention can be manufactured by winding the wire for the diagonal winding spring of the present invention spirally. A known method can be used as the winding method. When heat treatment for the purpose of strain removal is performed after spring processing, it can be made more difficult to sag. The temperature of this heat treatment is, for example, 200 ° C. or higher and 300 ° C. or lower. In addition, when the temperature of this heat treatment is increased as described above, the difference in Vickers hardness Hv can be increased as described above, and in addition to increasing the strength by removing strain, the spring characteristics and conductivity are further improved. Can also be planned.

  Hereinafter, a test example is given and the characteristic of the wire material for diagonal winding springs of this invention and the diagonal winding spring of this invention is demonstrated. Table 1 shows the materials of the materials used in the following test examples (content of each element: mass%). Steel type 1 is a SUS304 equivalent material, steel type 3 is a SUS316 equivalent material, Al (1) is an A1050 equivalent material, and Al (2) is an A2017 equivalent material.

[Test Example 1]
Steel 1 material strands shown in Table 1, and pipe materials made of annealed copper, pipe materials made of aluminum, and pipe materials made of aluminum alloy as raw material members, and an integrated product with raw material wires inserted into each pipe material The wire was subjected to wire drawing to produce a clad wire (composite wire) having a wire diameter of φ0.6 mm (Sample Nos. 1-1, 1-2, 1-3). The raw material wires and pipe materials were produced under known production conditions. For wire drawing for compounding, a manufacturing facility used for manufacturing copper wire or the like can be used. In this test, a composite wire was manufactured by adjusting the die angle and the degree of processing so that the inside of the composite wire was uniformly processed using the above manufacturing equipment. The composite wire 1 of the obtained sample Nos. 1-1, 1-2, 1-3 covers the entire circumference of the core wire 11 and the core wire 11 made of γ-based stainless steel, as shown in FIG. And an outer layer 12 made of annealed copper, aluminum, or an aluminum alloy. The thickness of the outer layer 12 is uniform over the entire circumference of the core wire 11.

  As a comparative material, a raw material wire made of annealed copper and a pipe material made of steel type 1 were prepared, and a clad wire with a wire diameter of φ0.6 mm was prepared (Sample No. 100). The raw material wires and pipe materials were produced under known production conditions. Compounding was performed using the same production equipment as Sample No. 1-1. As another comparative material, a wire material made of beryllium copper (Be: 0.15 mass% to 2.00 mass%) and having a wire diameter of φ0.6 mm was prepared (Sample No. 200).

  The prepared wire was spirally wound to produce a diagonally wound spring 2 (FIG. 1 (B)). The specifications of the spring are: major axis l (mm): 5.4 mm × minor axis b (mm): ellipse end face of 5.0 mm, spring length L: 45 mm, total number of turns: 50 (number of turns in FIG. 1 (B), spring The angle of inclination of the coil with respect to the axial direction is an example.

  The cross section of the wire which comprises the produced diagonal winding spring was taken, and the area ratio of the outer layer in the said cross section was investigated. The results are shown in Table 2. Moreover, the Vickers hardness Hv of a core wire and an outer side layer was measured using this cross section. The results are shown in Table 2. The Vickers hardness Hv is measured by pressing an indenter at the center position of the core wire and at the center position in the thickness direction of the outer layer in the cross section. In addition, the prepared wire can also take the cross section, and can measure the Vickers hardness Hv of a core wire and an outer layer similarly to the above.

  The non-linearity of the manufactured oblique winding spring was examined. The results are shown in Table 2. Here, assuming that the slant winding spring is used as a contact member and is pressed against the connector portion and the terminal, the slant winding spring 2 can be compressed in a direction perpendicular to its axial direction as shown in FIG. Is sandwiched between a pair of clamping members 50. In this state, the load when the displacement amount (spring pressing amount = displacement amount of the spring height (direction perpendicular to the axial direction of the slant winding spring)) is increased is examined. If the load hardly increases even if the amount of displacement is increased, or if the increase is small, it can be said that the oblique winding spring has a large region where a constant spring load can be obtained regardless of the amount of displacement. Therefore, here, the maximum value of the displacement amount at which the load change is within 20 N is defined as the length of the nonlinear region. It can be said that the longer this nonlinear region, the better the nonlinearity.

  The conductivity of the manufactured oblique winding spring was examined. The electrical conductivity was obtained by bringing a terminal member into contact with both ends of the slant winding spring. The results are shown in Table 2.

  The electrical resistivity of the manufactured oblique winding spring was examined. Here, two methods were used. As shown in FIG. 4, one end is sandwiched between a pair of terminal members 51 (here, Ag-plated brass plates) and measured by a four-terminal method (spring resistance value = total resistance). -(Resistance of one terminal member + resistance of the other terminal member)). The results are shown in Table 2 ("Both ends" in Table 2).

  As another example, assuming that the slant winding spring is used as a contact member and is sandwiched between the connector portion and the terminal, the slant winding spring 2 is placed in a direction perpendicular to its axial direction as shown in FIG. A pair of terminal members 52 (here, Ag-plated brass plates) were arranged so as to be sandwiched, and measurement was performed by a four-terminal method. The results are shown in Table 2 ("in use" in Table 2).

  The manufactured oblique winding spring was energized to investigate the degree of temperature rise. The energization condition is a current value of 100 A, and the temperature change from the start of energization is shown in FIG. Further, (temperature after the start of energization for a predetermined time (800 sec)) − temperature before energization is defined as an elevated temperature, and the elevated temperature is shown in Table 2.

  As shown in Table 2, sample Nos. 1-1, 1-2, and 1-3 are slantedly wound with a composite wire consisting of a core wire made of γ stainless steel and an outer layer made of copper, aluminum, or an aluminum alloy. The spring satisfies a Vickers hardness Hv difference of 350 or more. And the oblique winding spring of this sample No. 1-1, 1-2, 1-3 has a larger non-linear region than the oblique winding spring made of beryllium copper and the oblique winding spring whose outer layer is made of γ series stainless steel, It can be seen that the spring characteristics are excellent. The composite wire before the spring processing also has a Vickers hardness Hv difference of 350 or more, similar to the diagonal winding spring, and the diagonal winding spring substantially maintains the hardness difference of the composite wire used for the material. Yes.

  In particular, the diagonally wound spring of Sample No. 1-1 using soft copper for the outer layer has an electric resistance value of 0.12 m · Ω or less in a state assumed to be used in a contact member, and has a very low resistance. I understand that. Therefore, it can be said that this slant winding spring is excellent in conductivity. The reason for this result is that the outer layer is made of copper, which is very excellent in electrical conductivity, so that the contact resistance can be reduced, and the outer layer is made of a material with relatively low hardness. This is probably because the outer layer was deformed to increase the contact area and reduce the contact resistance. Further, it can be seen that the diagonally wound spring of Sample No. 1-1 has a high conductivity itself and a low resistance due to its low resistance. When an oblique winding spring is used as a contact member, if the resistance of the oblique winding spring is large, the amount of heat generation increases, and stress relaxation (sagging) may occur in the oblique winding spring due to a temperature rise accompanying heat generation. Depending on the magnitude of the stress relaxation, a predetermined spring load cannot be obtained. It can be said that the slant winding spring having a small electrical resistance as in sample No. 1-1 is less likely to cause stress relaxation due to temperature rise and can obtain a predetermined spring load satisfactorily. That is, it can be said that an oblique winding spring such as Sample No. 1-1 having high conductivity and low resistance when used as a contact member can be suitably used for the contact member.

  The diagonally wound springs of Samples Nos. 1-2 and 1-3 that use aluminum or an aluminum alloy for the outer layer also have a low resistance in the state assumed to be used for contact members, as with Sample No. 1-1. I understand that Therefore, it can be said that these slant winding springs can also be reduced in contact resistance due to deformation of the outer layer and are excellent in conductivity. In addition, the slant winding springs of Sample Nos. 1-2 and 1-3 can be reduced in weight by using aluminum or an aluminum alloy.

  From the above, it can be said that the outer layer of the diagonally wound spring used for the contact member is preferably made of a material having higher conductivity and relatively low hardness than γ-based stainless steel.

[Test Example 2]
Prepare the raw material strand of steel type 1 shown in Table 1 and a pipe material made of annealed copper as a material member, as in Sample No. 1-1 of Test Example 1, core wire: γ-based stainless steel, outer layer: annealed copper, A clad wire (composite wire) having a wire diameter of φ0.6 mm was produced. In this test, raw material wires and pipe materials of various sizes were prepared, and composite wires having different area ratios of the outer layers were produced.

  The obtained composite wire was made in the same manner as in Test Example 1 to produce an oblique winding spring (major axis l: 5.4 mm x minor axis b: 5.0 mm, spring length L: 45 mm, total number of windings: 50) with the same specifications. In the same manner as in Test Example 1, the area ratio of the outer layer, the nonlinearity of the spring, the electrical conductivity of the spring, and the electrical resistance of the spring (both ends, in use) were examined. The results are shown in Table 3. Moreover, it energized the produced diagonal winding spring and investigated the temperature rise degree. The energization condition is a current value of 100 A, and the temperature change from the start of energization is shown in FIG. Further, as in Test Example 1, the temperature rise after a lapse of a predetermined time is also shown in Table 3.

  As shown in Table 3, when the constituent materials of the composite wire of the oblique winding spring are the same, the higher the area ratio of the outer layer, the higher the conductivity and the lower resistance, and the lower the area ratio, the larger the nonlinear region I understand that. Further, when the core wire is γ-type stainless steel, even if the area ratio of the core wire is small (even if the area ratio of the outer layer is large), the outer layer is γ-type stainless steel (Sample No. in Test Example 1). It can be seen that the spring characteristics are superior to 100). Therefore, when the core wire is γ stainless steel, the ratio of the outer layer can be increased, so that the conductivity can be improved. It can also be seen that the temperature rise is small by increasing the proportion of the outer layer having a relatively lower resistance than the core wire. Conversely, when the area ratio of the outer layer is low, it can be said that the spring characteristics are further improved and a light spring can be obtained. Thus, it can be said that the oblique winding spring which is a composite wire having a specific stacking order and is composed of a material whose hardness difference between the inside and outside satisfies a specific range is excellent in both spring characteristics and conductivity. In addition, a composite wire that is a composite wire in a specific stacking order and that is composed of a material that satisfies a specific range in hardness difference between the inside and outside, an oblique winding spring that is excellent in both spring characteristics and conductivity is obtained. It can be said. Furthermore, from this test, when the length of the non-linear region and the conductivity during use are equal to or greater than the spring made of beryllium copper (Sample No. 200 of Test Example 1), the area ratio of the outer layer is 30% to 90% is preferable.

  In this test, it has been confirmed that the composition and hardness difference of the wire constituting the oblique winding spring, the area ratio of the outer layer, etc. substantially maintain the value of the composite wire before the spring processing.

[Test Example 3]
Prepare a raw material wire of each steel type shown in Table 1 and a pipe material made of soft copper as a raw material member, as in Sample No. 1-1 of Test Example 1, core wire: γ-based stainless steel, outer layer: soft copper, A clad wire (composite wire) having a wire diameter of φ0.6 mm was produced. In this test, composite wires having different core wire compositions were produced.

  The obtained composite wire was made in the same manner as in Test Example 1 to produce an oblique winding spring (major axis l: 5.4 mm x minor axis b: 5.0 mm, spring length L: 45 mm, total number of windings: 50) with the same specifications. In the same manner as in Test Example 1, the Vickers hardness Hv of the core wire and the outer layer, the area ratio of the outer layer, the non-linearity of the spring, the conductivity of the spring, and the electrical resistance of the spring (both ends, in use) were examined. The results are shown in Table 4. Moreover, it energized the produced diagonal winding spring and investigated the temperature rise degree. The energization condition is a current value of 100 A, and the temperature change from the start of energization is shown in FIG. Further, similarly to Test Example 1, the temperature rise after a predetermined time is also shown in Table 4.

  As shown in Table 4, compared to sample No. 3-1 (same composition as sample No. 1-1), sample No. 3-2 rich in nitrogen, sample No. 3- containing Nb and Ti 3 and 3-4 show a large difference in Vickers hardness Hv. For this reason, Sample Nos. 3-2 to 3-4 maintain a conductivity comparable to that of Sample No. 3-1, while having a larger non-linear region and better spring characteristics. It can also be seen that sample Nos. 3-1 to 3-4 have a small temperature rise.

  As shown in Table 4, when γ-type stainless steel with a high Ni equivalent such as SUS316 is used for the core wire, the hardness difference may not be sufficiently obtained. In this case, for example, it is conceivable to increase the hardness difference by increasing the degree of processing (area reduction) during wire drawing to increase the strength of the core wire. However, since γ-type stainless steel having a high Ni equivalent has a high stacking fault energy, work hardening is often insufficient even when the degree of work is increased as described above. Thus, it can be said that adjusting the composition of the γ-based stainless steel can be used as one of the methods for increasing the difference in the Vickers hardness Hv because the composition of the stainless steel has a great influence on the strength.

[Test Example 4]
Prepare a raw material strand of steel type 1 or steel type 2 shown in Table 1 and a pipe material made of annealed copper as a raw material member, and in the same manner as Sample No. 1-1 in Test Example 1, core wire: γ-based stainless steel, outer layer : Clad wire (composite wire) with mild copper and wire diameter: φ0.6 mm was prepared.

  The obtained composite wire was made in the same manner as in Test Example 1 to produce an oblique winding spring (major axis l: 5.4 mm × minor axis b: 5.0 mm, spring length L: 45 mm, total number of windings: 50) having the same specifications. . The springs of Sample Nos. 4-2, 4-4, and 4-5 were heat treated after the spring processing (Sample No. 4-2: 350 ° C, Sample No. 4-4: 400 ° C, No. 4-5: 450 ° C, retention time: 30 minutes for all). For the obtained spring, the non-linearity of the spring, the conductivity of the spring, and the electrical resistance of the spring (both ends, in use) were examined in the same manner as in Test Example 1. The springs No. 4-2, 4-4, and 4-5 that were heat-treated after spring processing were examined for the above characteristics after the heat treatment. The results are shown in Table 5. Further, the cross section of the wire constituting the obtained spring was taken, and the area ratio of the outer layer, the core wire, and the Vickers hardness Hv of the outer layer were examined in the same manner as in Test Example 1. The results are shown in Table 5. Furthermore, the degree of the temperature rise was examined by energizing the manufactured oblique winding spring. The energization condition is a current value of 100 A, and the temperature change from the start of energization is shown in FIG. In addition, as in Test Example 1, the temperature rise after a predetermined time has also been shown in Table 5.

  As shown in Table 5, it can be seen that the difference in the Vickers hardness Hv can be further increased by performing the heat treatment even if the constituent materials of the composite wire constituting the oblique spring are the same. In particular, it can be seen that the Vickers hardness difference can be further increased by heat treatment by containing a large amount of C and N that can easily form a Cottrell atmosphere. Samples 4-2, 4-4, and 4-5 that have been heat-treated have lower resistance during use than the samples No. 4-1 and 4-3 that have not been heat-treated, and have a non-linear region. Larger and better in spring characteristics. In addition, sample Nos. 4-2, 4-4, and 4-5 that have undergone heat treatment have a lower resistance than sample Nos. 4-1 and 4-3 that have not undergone heat treatment, resulting in a small increase in temperature. I understand that. It can be seen that even when heat treatment is performed in this manner, the difference in the Vickers hardness Hv can be easily increased, and an obliquely wound spring having lower resistance, excellent conductivity, and superior spring characteristics can be obtained. The reason for this is that the heat treatment increases the hardness and strength of the γ-based stainless steel that constitutes the core wire, and the copper that constitutes the outer layer precipitates and separates the Fe component that has dissolved and diffused from the core wire during wire drawing. This is considered to be because the conductivity was increased and the film was softened and easily deformed, and a sufficient contact area with the terminal member could be secured.

[Example of use]
Diagonal winding made of a composite wire made in Test Example 1 to Test Example 4 described above, made of a material having excellent conductivity such as γ stainless steel and outer layer made of copper, and having a Vickers hardness Hv difference of 350 or more. The spring can be suitably used as a contact member for connector connection.

  For example, as shown in FIG. 10 (A), when the connector connection is made by inserting the male terminal 61A into the insertion hole 62 of the female connector part 60A, the insertion hole 62 of the female connector part 60A is linear. There is a structure in which the mounting groove 63 is provided, and the oblique winding spring 2 is disposed in the longitudinal direction of the mounting groove 63. This structure is used, for example, for an electrical device having an energization current value of 300 A or less, such as a storage battery or a power generation device. When the male terminal 61A is fitted into the female connector part 60A, the female connector part 60A and the male terminal 61A are held in a pressed state by the biasing force of the oblique winding spring 2, and the biasing force The mating state is fixed. In particular, since the non-linear region is large by using the slant winding spring of the present invention, a constant spring load can be applied to the female connector portion 60A and the male terminal 61A regardless of the displacement of the spring.

  Alternatively, for example, as shown in FIG. 10 (B), the insertion hole 62 of the female connector portion 60B is provided with an annular mounting groove 63 along its circumferential direction, and the oblique winding spring 2 is arranged in an annular shape. Is mentioned. In this structure, the entire circumference of the male terminal 61B can contact the slant winding spring 2, and both the connector portion and the terminal can sufficiently receive the spring load. Note that the female connector portion 60B shown in FIG. 10 (B) has a plurality (three in this case, possibly two or more) of insertion holes 62, and a structure in which a plurality of male terminals 61B are fitted. It is. This structure is used for a device having an energization current value of about 100 amperes to about 200 amperes, such as an in-vehicle device such as a hybrid vehicle or an electric vehicle.

  Alternatively, for example, as shown in FIG. 10C, there is no mounting groove in the insertion hole 62 of the female connector portion 60C, and an annular mounting groove 64 is provided in the circumferential direction of the male terminal 61C. A structure in which the winding spring 2 is arranged in an annular shape is mentioned. In this way, the oblique winding spring serving as the contact member can be disposed on either the female member or the male member used for connector connection.

  Note that the present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the gist of the present invention. For example, the oblique winding spring of the present invention can be used for a contact member for connector connection by a male connector portion and a female terminal.

  The diagonally wound spring of the present invention can be suitably used for a contact member in connector connection between various electric devices such as a storage battery, a power generation device, and an in-vehicle component and an electric wire. The steel wire for an oblique winding spring of the present invention can be suitably used as a material for the oblique winding spring of the present invention.

1 Composite wire (obliquely wound spring wire) 11 Core wire 12 Outer layer
50 Holding member 51,52 Terminal member
60A, 60B, 60C Female connector 61A, 61B, 61C Male terminal 62 Insertion hole 63, 64 Mounting groove

Claims (10)

A wire for an oblique winding spring used as a material for an oblique winding spring that is compressed in a direction perpendicular to the axial direction of the spring,
Consists of a composite wire comprising a core wire composed of austenitic stainless steel and an outer layer provided on the outer periphery of the core wire,
The outer layer is composed of one kind of metal selected from copper, copper alloy, aluminum, and aluminum alloy,
The difference is 400 or more der Ru swash Me wound spring wire of Vickers hardness Hv of the outer layer and the core wire. An oblique winding spring that is compressed in a direction perpendicular to the axial direction of the spring,
Constructed by spirally winding a composite wire comprising a core wire composed of austenitic stainless steel and an outer layer provided on the outer periphery of the core wire,
The outer layer is composed of one kind of metal selected from copper, copper alloy, aluminum, and aluminum alloy,
The core wire and the outer layer and the Vickers hardness Hv difference over 400 der Ru swash Me coil spring of. The austenitic stainless steel is
By mass%, C: 0.05% to 0.1% or less, and N: obliquely wound spring wire according to at least 0.1% 0.3% 請 Motomeko 1 that meet at least one. The composite wire obliquely wound spring wire according to 請 Motomeko 1 or claim 3 area ratio Ru der 30% or more than 90% of the outer layer to the cross section of the. The austenitic stainless steel is
Satisfies at least one of C: 0.05% to 0.1% and N: 0.1% to 0.3% by mass%, Si: 0.3% to 2.0%, Mn: 0.5% to 4.0%, Cr: 16% more than 20% or less, Ni: contained 6.0% or more 14.0% or less, 請 Motomeko 1 balance ing Fe and inevitable impurities, claim 3, and the oblique winding according to any one of claims 4 Spring wire. Furthermore, by mass%, Mo: 0.1% to 4.0% or less, Nb: 0.1% or more and 2.0% or less, and Ti: billed you containing one or two elements selected from 0.1% to 2.0% or less Item 6. A wire for an obliquely wound spring according to Item 5 . The austenitic stainless steel is
By mass%, C: 0.05% to 0.1% or less, and N: oblique coil spring according to 請 Motomeko 2 that meet at least one of 0.1% to 0.3% or less. Oblique winding spring according to 請 Motomeko 2 or claim 7 area ratio of the outer layer is Ru der 90% or less than 30% of the cross-section of the composite wire. The austenitic stainless steel is
Satisfies at least one of C: 0.05% to 0.1% and N: 0.1% to 0.3% by mass%, Si: 0.3% to 2.0%, Mn: 0.5% to 4.0%, Cr: 16% more than 20% or less, Ni: contained 6.0% or more 14.0% or less, 請 Motomeko 2 balance ing Fe and inevitable impurities, oblique winding according to any one of claims 7, and claim 8 Spring. Furthermore, by mass%, Mo: 0.1% to 4.0% or less, Nb: 0.1% or more and 2.0% or less, and Ti: billed you containing one or two elements selected from 0.1% to 2.0% or less Item 10. The oblique winding spring according to Item 9 .

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