Contact material and relay using same

Abstract

The present invention provides: a contact material for a contact which has high inrush current resistance and can be stably opened and closed for a long period of time; and a relay which uses the contact material.　Provided is a contact material that has a material structure in which an oxide of a metal M is dispersed in a matrix that is formed of Ag or the like. The metal M includes Sn, the metal component of the contact material contains the metal M, the balance Ag and an inevitable impurity metal, and the content rate of the metal M relative to the total weight of all the metal components of the contact material is more than 8 wt% but not more than 20 wt%.

Description

Contact material and relay using the same

[0001] The present invention relates to a contact material and a relay using the same.

[0002] When power is applied to an electric circuit that operates an electric load such as a motor or a lamp load such as an incandescent lamp, an inrush current, which is a current much larger than the steady-state current, flows through the electric circuit. When the inrush current occurs, the arc heat from the arc discharge can cause welding and wear of the relay contacts, which can render the relay unusable. In particular, if the inrush current occurs during bouncing of the moving contacts, the welding and wear can be severe.

[0003] As a relay that prevents welding between contacts due to inrush current, for example, an electromagnetic relay with contacts described in Patent Document 1 has been proposed. The contacts include a current-carrying contact and an inrush-current-resistant contact that are different in shape and / or material, and a slit that partially separates the contacts. The contacts are said to reduce defects caused by contact welding by, for example, imparting flexibility to the spring material with the slit, and by designing the inrush-resistant contact to protrude further than the current-carrying contact, so that the inrush-resistant contact makes contact first and then the current-carrying contact.

[0004] Japanese Patent Application Laid-Open No. 2005-183097

[0005] In recent years, with the need for miniaturization of devices and high-density mounting of relays, there has been a demand for miniaturization of relays. However, the technology described in Patent Document 1 requires the slit as an essential component, which requires a sufficient gap between the contacts. As a result, the relay described in Patent Document 1 is inevitably larger than a normal relay and has a complex mechanism. In other words, there is a problem in that it is difficult to manufacture a compact relay using the contacts described in Patent Document 1. Under these circumstances, there is a demand for technology that provides inrush current resistance to the contacts of a compact relay, enabling stable contact opening and closing without welding between the contacts, even under conditions where an inrush current is repeatedly applied.

[0006] Therefore, an object of one aspect of the present invention is to provide a contact material that has high inrush current resistance and can provide contacts that can be stably opened and closed for a long period of time, and a relay that can be miniaturized and uses the contact material.

[0007] In order to solve the above problems, a contact material according to one aspect of the present invention has a material structure in which an oxide of a metal M is dispersed in a matrix made of Ag and / or an Ag alloy, wherein the metal M includes Sn, and the metal components of the contact material include the metal M with the remainder being Ag and unavoidable impurity metals, and the content of the metal M relative to the total weight of all the metal components of the contact material is more than 8 wt % and not more than 20 wt %.

[0008] According to the above configuration, Sn is converted into an oxide (SnO ２ ) provides the contact with wear resistance, adhesion resistance, etc., and since the content of the metal M is more than 8 wt %, sufficient wear resistance and adhesion resistance can be imparted to the contact. Furthermore, with the above-mentioned configuration, since the content is 20 wt % or less, it is easy to disperse oxides of the metal M in the matrix. Therefore, the contact has excellent mass productivity and can maintain low contact resistance.

[0009] In a contact material according to one aspect of the present invention, the metal M contains Te and / or Bi, and the content of Te and / or Bi relative to the total weight of all metal components of the contact material is 0.2 wt % or more and 1.0 wt % or less.

[0010] With this configuration, it is believed that the differences in melting and boiling points, as well as the differences in brittleness, between Ag and Te and / or Bi give the contacts resistance to inrush current, allowing the contacts to be separated with a weak separation force and reducing contact wear.

[0011] A relay according to one aspect of the present invention comprises: a fixed piece fixed to a base; a fixed contact provided on the fixed piece; a movable piece fixed at a fixed end to the base and including an elastically deformable portion; a movable contact provided on the movable piece and arranged opposite the fixed contact; a card that presses the movable piece so as to elastically deform, thereby connecting the movable contact to the fixed contact; and a drive unit that operates the card by controlling the flow of current to an electromagnet, wherein the movable piece has a contact portion that is convex in a direction facing the card, and the movable piece and the card contact each other at the contact portion, and the fixed contact and the movable contact contain the contact material according to claim 1 or 2.

[0012] According to the above configuration, a convex contact portion is provided on the movable piece. Therefore, while the movable piece is pressed against the card and elastically deforms, the position where the movable piece and the card come into contact is limited to the contact portion. In other words, while the movable piece is pressed against the card and elastically deforms, the pressing force is applied to approximately the same position on the movable piece, so the moment applied to the movable piece can be kept approximately constant. Therefore, welding caused by arcing that occurs when the fixed contact and the movable contact momentarily separate when the contact pressure between them is insufficient can be suppressed. Furthermore, since the fixed contact and the movable contact contain the contact material of the present invention, they have excellent resistance to inrush current and wear resistance.

[0013] In the relay according to one aspect of the present invention, the contact portion is provided on the movable piece at a position opposite the fixed end with respect to the movable contact.

[0014] With the above configuration, the movable piece is pressed at the free end side of the movable contact, so it is pressed with a larger moment than when it is pressed at the fixed end side of the movable contact, thereby making it possible to increase the contact pressure between the fixed contact and the movable contact.

[0015] In the relay according to one aspect of the present invention, the movable piece and the card come into contact only at the contact portion throughout the entire movable range in which the card presses the movable piece.

[0016] According to the above-mentioned configuration, the card and the movable piece do not come into contact with each other at any part other than the contact portion, so that it is possible to prevent wear from occurring at any part other than the contact portion.

[0017] In the relay according to one aspect of the present invention, the convex shape of the contact portion is a curved surface.

[0018] According to the above configuration, the curved surface of the contact portion comes into contact with the card, so that wear due to contact can be reduced.

[0019] In one aspect of the relay of the present invention, when the card presses the movable piece to the farthest extent within the movable range in which the card presses the movable piece, a plane that passes through the contact point where the contact portion and the card are in contact and is parallel to the surface of the movable piece at the portion of the movable piece that extends from the movable contact toward the base of the contact portion does not pass through the area occupied by the material that makes up the movable contact.

[0020] Assume that the relay is installed so that the normal direction to the surface of the movable piece is horizontal, in other words, so that the contact portion is located above the movable contact. In this case, with the above configuration, when the card is fully pressed into the movable piece, the contact point where the contact portion and the card are in contact will not be above the area occupied by the components that make up the movable contact. Therefore, even when the relay is installed as described above, it is possible to prevent wear powder generated at the contact point from falling onto the movable contact, thereby preventing contact failure due to wear powder.

[0021] In one embodiment of the relay of the present invention, the cross section of the contact portion taken along a plane including the main axis direction from the fixed end to the contact portion and the direction in which the contact portion moves when pressed is convex, the cross section taken along a plane having the main axis direction as its normal direction is linear, and the width of the opposing surface facing the contact portion on the card in a direction perpendicular to the main axis direction is shorter than the width of the contact portion in a direction perpendicular to the main axis direction.

[0022] According to the above configuration, the end of the contact portion in the direction perpendicular to the main axis direction does not come into contact with the opposing surface of the card, thereby preventing wear and damage to the opposing surface of the contact portion.

[0023] In one embodiment of the relay of the present invention, the contact portion has a convex cross section along a plane including the main axis direction from the fixed end to the contact portion and the direction in which the contact portion moves when pressed, and a linear cross section along a plane normal to the main axis direction, and both ends of the opposing surface facing the contact portion on the card in a direction perpendicular to the main axis direction are chamfered.

[0024] According to the above configuration, the end of the contact portion in the direction perpendicular to the main axis direction does not come into contact with the opposing surface of the card, thereby preventing wear and damage to the opposing surface of the contact portion.

[0025] In one aspect of the relay of the present invention, when the movable contact and the fixed contact are in contact within the movable range in which the card presses against the movable piece, the direction of the force applied by the card to the contact portion is directed toward the fixed end rather than the direction in which the contact portion moves due to the pressure.

[0026] With the above configuration, it is possible to more effectively prevent the fixed contact from being momentarily separated from the movable contact when the movable piece is pressed all the way in by the card, thereby preventing welding caused by arcing that occurs when the fixed contact is momentarily separated from the movable contact.

[0027] According to one aspect of the present invention, it is possible to provide a contact material that has high inrush current resistance and can provide contacts that can be stably opened and closed for a long period of time, and a relay that can be made compact using the contact material.

[0028] 1 is a plan view of a state in which the opposing surface 41 of the card 4 and the contact portion 32 of the movable piece 3 are in contact with each other, as viewed from above in FIG. 1 ; and FIG. 2 is a side view of a relay according to the present embodiment, showing a state in which the opposing surface 41 and the contact portion 32 of the movable piece 3 are in contact with each other, when the movable contact 31 and the fixed contact 21 are in contact with each other.

[0029] An embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described below with reference to the drawings. The present invention is not limited to the configurations described below, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0030] [1. Contact Material] (1-1. Composition, etc. of Contact Material) The contact material according to this embodiment (hereinafter also referred to as "the contact material of the present invention") is a contact material having a material structure in which an oxide of a metal M is dispersed in a matrix made of Ag and / or an Ag alloy, wherein the metal M includes Sn, the metal components of the contact material include the metal M with the remainder being Ag and unavoidable impurity metals, and the content of the metal M relative to the total weight of all the metal components of the contact material is more than 8 wt % and not more than 20 wt %.

[0031] In small relays, the contact force and opening force between the contacts are set low due to their small size. Therefore, if the contacts are welded by an inrush current, it is difficult to open the contacts by increasing these forces. Therefore, the inventors investigated ways to give the contact material inrush current resistance by devising the composition of the contact material.

[0032] Typically, low-resistance Ag or Ag alloy is used as the matrix contact material to provide relays with current-carrying properties. However, Ag has a relatively low melting point of 961°C and boiling point of 2155°C, so it melts when an arc occurs due to an inrush current, causing the contacts to fuse together. Furthermore, once the Ag has fused with the contacts, it is not easy to separate them. While it is conceivable to apply a strong opening force by using a large electromagnet to separate the fused Ag, this method is not compatible with the miniaturization of relays and therefore cannot be adopted.

[0033] Therefore, the inventors have dispersed an oxide of metal M in a matrix made of Ag or an Ag alloy, and set the content of metal M to more than 8 wt % and not more than 20 wt % relative to the total weight of all metal components of the contact material. Metal M includes Sn.

[0034] The oxide of metal M is used to impart wear resistance and adhesion resistance to the contact. In the contact material of the present invention, Sn is present in the form of an oxide (SnO ２ ) provides the contact with resistance to wear and adhesion, and the content of the metal M is more than 8 wt %, so that the contact can be provided with sufficient resistance to wear and adhesion.

[0035] On the other hand, if the content exceeds 20% by weight, it becomes difficult to disperse the oxide of metal M in the matrix made of Ag and / or Ag alloy, which is undesirable because it causes inconvenience in mass production of contacts and also leads to an increase in contact resistance. In the contact material of the present invention, the content is 20% by weight or less, so that the oxide of metal M can be easily dispersed in the matrix. Therefore, the contact material is excellent in mass productivity and can maintain low contact resistance.

[0036] From the viewpoint of imparting wear resistance and welding resistance to the contacts and ensuring mass production of the contacts, the content of the metal M is preferably 10% by weight or more and 18% by weight or less, and more preferably 12% by weight or more and 15% by weight or less.

[0037] The matrix is ​​a non-oxide material capable of dispersing an oxide of metal M, and is made of Ag and / or an Ag alloy. The Ag refers to pure Ag. The Ag alloy is an alloy of Ag and metal M, or an alloy of Ag and unavoidable impurity metals. The Ag alloy does not have to be an alloy having a single composition. For example, it may be made of multiple Ag alloys with different amounts of metal M or unavoidable impurity metals dissolved therein. The concentration of metal M or unavoidable impurity metals in the matrix is ​​preferably 4 wt% or less, more preferably 2 wt% or less, and even more preferably 0 wt%.

[0038] The metal M is dispersed in the matrix as an oxide, and in the contact material of the present invention, the oxide content is specified based on the content of the metal M, which is a metal other than Ag. The content of the metal M is specified based on the total weight of all metal components in the contact material. Since Te and / or Bi, which will be described later, are also contained in the contact material as oxides, in this specification the content of Te and / or Bi oxides is specified as the content of Te and / or Bi relative to the total weight of all metal components in the contact material.

[0039] Sn is SnO ２ The Sn content of the contact material relative to the total weight of all metal components is preferably 7% by weight or more and 18% by weight or less, more preferably 7% by weight or more and 15% by weight or less, even more preferably 10% by weight or more and 15% by weight or less, and particularly preferably 12% by weight or more and 15% by weight or less, from the viewpoint of improving the welding resistance of the contact.

[0040] The metal M may further contain, in addition to Sn, other metals such as In, Ni, Te and / or Bi, which will be described later. ２ O ３ The other metals may be one type or two or more types.

[0041] The In content of the contact material relative to the total weight of all metal components is preferably 2% by weight to 10% by weight, and more preferably 4% by weight to 8% by weight, from the viewpoint of improving the welding resistance of the contacts. Also, the Ni content of the contact material relative to the total weight of all metal components is preferably 0.1% by weight to 4% by weight, and more preferably 0.05% by weight to 2% by weight, from the viewpoint of improving the welding resistance of the contacts.

[0042] The remaining Ag is Ag that constitutes the matrix made of Ag and / or Ag alloy. Examples of the unavoidable impurity metals include Li, Na, Mg, Al, Si, K, Ca, Ti, Cr, Mn, Fe, Co, Cu, Zn, Ge, Y, Zr, Nb, Mo, Pd, Cd, Ta, W, Pb, and La. The content of each of the unavoidable impurity metals is preferably 0% by weight or more and 1% by weight or less, and more preferably 0.05% by weight or more and 1% by weight or less, based on the total weight of all metal components of the contact material.

[0043] The contact material of the present invention may contain, in addition to the matrix and the oxide of the metal M, oxygen and non-metals as unavoidable impurity elements. Examples of the non-metals include C, S, and P. The oxygen content of the contact material of the present invention is preferably 0.025% by weight or more and 2% by weight or less, when the weight of the entire contact material is taken as 100% by weight. The content of each of the non-metals in the contact material of the present invention is preferably 0% by weight or more and 0.1% by weight or less, when the weight of the entire contact material is taken as 100% by weight.

[0044] In the contact material of the present invention, it is preferable that the metal M contains Te and / or Bi, and that the content of Te and / or Bi relative to the total weight of all metal components of the contact material is 0.2 wt % or more and 1.0 wt % or less.

[0045] Te and Bi have lower melting and boiling points than Ag and are brittle materials. A brittle material is one that breaks when cracks propagate within the material with almost no plastic deformation when a force is applied. The inventors discovered that higher inrush current resistance can be achieved when the content of Te and / or Bi is 0.2 wt % or more and 1.0 wt % or less relative to the total weight of all metal components of the contact material.

[0046] According to the above-mentioned configuration, the difference in melting point and boiling point between Ag and Te and / or Bi, as well as the difference in brittleness, weakens the weldability between the contacts, allowing the contacts to be opened with a weak opening force. Therefore, the above-mentioned configuration provides the contacts with high inrush current resistance. Furthermore, since this eliminates the need for a large electromagnet that generates a strong opening force, the relay equipped with the above-mentioned contacts can be made smaller.

[0047] In this embodiment, the metal M contains Sn and Te and / or Bi. As described above, Te and / or Bi impart adhesion resistance to the contact due to differences in melting point and boiling point and brittleness compared to Ag. This adhesion resistance is stronger than that of Sn, and as shown in the examples described below, it is possible to impart stronger adhesion resistance to the contact than when only oxides not containing Te and / or Bi are dispersed in the matrix.

[0048] When the content of Te and / or Bi relative to the total weight of all metal components of the contact material is 0.2 wt % or more, the contacts can be provided with long-term welding resistance. On the other hand, when the content exceeds 1.0 wt %, the contacts tend to wear out quickly. Since the contact material of the present invention has a content of less than 1.0 wt %, it has little effect on contact wear. Therefore, contact wear can be reduced.

[0049] From this viewpoint, the content is more preferably 0.4% by weight or more and 0.8% by weight or more, and even more preferably 0.6% by weight or more and 0.8% by weight or more. When Te and Bi are used, the ratio of their contents is not particularly limited, as long as the total content of Te and Bi is 0.2% by weight or more and 1.0% by weight or less. The "total weight of all metal components in the contact material" refers to the sum of the weights of Ag and / or Ag alloys constituting the matrix, metal M contained in the oxide of metal M, and unavoidable metal impurities.

[0050] (1-2. Manufacturing Method of Contact Material) The contact material of the present invention described above can be manufactured by, for example, the internal oxidation method or the powder metallurgy method. In the internal oxidation method, for example, Ag and / or Ag alloy and metal M are first melted in a high-frequency melting furnace to cast an ingot. Next, the ingot is cut into individual pieces with sides of 3 mm or less and then internally oxidized to manufacture the contact material. The conditions for internal oxidation are preferably an oxygen partial pressure of 0.9 MPa or less (above atmospheric pressure), a temperature of 300°C to 900°C, and a treatment time of 24 hours or more.

[0051] In the powder metallurgy method, for example, a contact material is produced by mixing powder of Ag and / or Ag alloy with powder of oxide of metal M (both of which have an average particle size of 0.5 to 100 μm) and compressing the mixture.

[0052] (1-3. Manufacturing Method of Contacts) The fixed contacts and movable contacts used in the relays described below can be manufactured, for example, by the following method. First, a contact material obtained by internal oxidation or powder metallurgy is compression molded to form a billet with a diameter of 50 mm. Next, this billet is hot extruded and then drawn into a wire with a diameter of 2.3 mm, which is then processed by a header machine to produce a rivet-type contact material.

[0053] [2. Relay] A relay according to this embodiment comprises: a fixed piece fixed to a base; a fixed contact provided on the fixed piece; a movable piece fixed at a fixed end to the base and including an elastically deformable portion; a movable contact provided on the movable piece and arranged opposite the fixed contact; a card that presses the movable piece so as to elastically deform, thereby connecting the movable contact to the fixed contact; and a drive unit that operates the card by controlling the flow of electricity to an electromagnet, wherein the movable piece has a contact portion that is convex in a direction facing the card, and the movable piece and the card are in contact at the contact portion, and the fixed contact and the movable contact contain the contact material of the present invention.

[0054] An embodiment of the present invention will be described in detail below. Fig. 1 is a side cross-sectional view of a relay 1 according to this embodiment. As shown in the figure, the relay 1 includes a fixed piece 2, a movable piece 3, a card 4, a base 5, an armature 6, and a drive unit 7. In practice, the above components of the relay 1 are disposed inside a case (not shown).

[0055] The fixed piece 2 is fixed to the base 5, with one end protruding into the case and the other end protruding outside as an external connection terminal. The fixed piece 2 is made of a conductive material, such as Cu. A fixed contact 21 is provided near the end of the part of the fixed piece 2 that protrudes inside. The fixed contact 21 is made of a conductive material, such as Cu, and is electrically connected to the fixed piece 2.

[0056] The movable piece 3 is fixed to the base 5 at its fixed end 33, with one end protruding into the case and the other end protruding externally as an external connection terminal. The movable piece 3 is made of a conductive material, such as Cu. A movable contact 31 is provided on the portion of the movable piece 3 that protrudes inward. The movable contact 31 is made of a conductive material, such as Cu, and is electrically connected to the movable piece 3. In this embodiment, the entire movable piece 3 is made of an elastic metal, but this is not limited thereto. It is sufficient that at least a portion between the fixed end 33 and the movable contact 31 is provided that is elastically deformable. The movable contact 31 is disposed opposite the fixed contact 21, and is switchable between a state of contact with the fixed contact 21 and a state of not contacting the fixed contact 21 by elastic deformation of the movable piece 3.

[0057] A contact portion 32 is provided on the free end side of the portion of the movable piece 3 that protrudes into the case. The contact portion 32 comes into contact with the opposing surface 41 of the card 4, and thereby a pressing force from the card 4 is applied to the movable piece 3.

[0058] In the example shown in Figure 1, the direction in which the movable piece 3 extends from the base 4 into the case is vertically upward, but the arrangement direction of the relay 1 is not limited to this, and for example, the direction in which the movable piece 3 extends from the base 4 into the case may be horizontal.

[0059] The card 4 is disposed between the drive unit 7 and the movable piece 3, and transmits the pressing force from the armature 6, which is rotated by the drive unit 7, to the movable piece 3. The card 4 is made of, for example, resin, but is not limited to this.

[0060] The card 4 has a base formed of a plate-like member extending in the vertical direction, and one end (the lower end in FIG. 1 ) of the card 4, which is a card fixing end 42, is rotatably held relative to the base 5. A protrusion is provided on the card 4 toward the armature 6, and a pressing force from the armature 6 is applied to the card 4 when the armature 6 abuts against the protrusion.

[0061] The other end (the upper end in FIG. 1 ) of the card 4 is provided with an opposing surface 41. When a pressing force from the armature 6 is applied to the protrusion, the card 4 rotates around the fixed end 42, causing the opposing surface 41 to come into contact with the contact portion 32 of the movable piece 3, and the pressing force is applied to the movable piece 3.

[0062] The drive unit 7 generates an electromagnetic force for operating the card 4. The drive unit 7 is composed of a coil, a bobbin, an iron core, a yoke, etc., and the electromagnetic force is switched on and off by external current control. The armature 6 is rotatably supported on the upper end of the yoke of the drive unit 7. The armature 6 rotates due to the electromagnetic force generated by the coil of the drive unit 7, and presses against the card 4.

[0063] 2 is a perspective view showing the appearance of the movable piece 3. As shown in the figure, the movable piece 3 is formed by bending a molded plate-shaped metal member. As described above, the contact portion 32 is provided on the free end side of the movable piece 3.

[0064] More specifically, the contact portion 32 is provided on the movable piece 3 at a position opposite the fixed end 33 with respect to the movable contact 31. With this configuration, the movable piece 3 is pressed on the free end side of the movable contact 31, and therefore is pressed with a larger moment compared to when the movable piece 3 is pressed on the fixed end 33 side of the movable contact 31. Therefore, the contact pressure between the fixed contact 21 and the movable contact 31 can be increased.

[0065] The contact portion 32 is made of a member that has a convex shape in the direction facing the facing surface 41 of the card 4. The convex shape of the contact portion 32 is also curved. As a result, the curved surface of the contact portion 32 comes into contact with the facing surface 41 of the card 4, thereby reducing wear on the card 4 due to contact.

[0066] Furthermore, in the contact portion 32, a cross section taken along a plane P1 including the main axis direction AX from the fixed end 33 to the contact portion 32 and the direction D1 in which the contact portion 32 moves when pressed has a convex shape that is convex toward the opposing surface 41, and a cross section taken along a plane P2 having the main axis direction AX as its normal direction has a linear shape. That is, the contact portion 32 has a curved surface that extends linearly in a direction perpendicular to the main axis direction AX.

[0067] 2, the convex shape of the contact portion 32 is formed by bending the plate-like metal that constitutes the movable piece 3, but this is not limiting. For example, the convex shape may be formed by increasing the thickness of the contact portion 32. Furthermore, the contact portion 32 may be formed of a material different from the material that constitutes the movable piece 3. In this case, the contact portion 32 may be made of resin.

[0068] 2, a slit is provided in the region between the fixed end 33 and the movable contact 31, but this is not limiting and the slit may not be provided. Also, a structure in which the movable contacts 31 are provided on both sides of the slit, i.e., a structure in which two movable contacts 31 are provided, may be used.

[0069] Next, the operation when the card 4 pushes the movable piece 3 will be described. FIG. 3 shows, as a comparative example, the operation of a configuration in which a protrusion 410 is provided on the card 40 side and no protrusion is provided on the movable piece 30 side. 301 shows the state at the time when the protrusion 410 of the card 40 comes into contact with the movable piece 30. The distance between the center of the movable contact 310 and the contact point P10 between the protrusion 410 and the movable piece 30 in this state is defined as L10. Also, 302 shows the state in which the movable piece 30 is elastically deformed by the pressure of the card 40, and the movable contact 310 comes into contact with the fixed contact 210 on the fixed piece 20. The distance between the center of the movable contact 310 and the contact point P10 between the protrusion 410 and the movable piece 30 in this state is defined as L20.

[0070] While the free end of the movable piece 30 is being pressed by the card 40, it moves in a generally arcuate shape around the fixed end of the movable piece 30. The protrusion 410 of the card 40 also moves in a generally arcuate shape around the fixed end of the card 40. Therefore, when the arrangement shown in FIG. 3 changes from the state shown in 301 to the state shown in 302, the distance L20 becomes shorter than the distance L10. That is, the contact point P10 between the protrusion 410 and the movable piece 30 moves closer to the movable contact 310. In this case, the position where the pressing force is applied to the movable piece 30 changes, and the moment applied to the movable piece 30 decreases. Therefore, if the contact pressure between the fixed contact and the movable contact is insufficient, the fixed contact and the movable contact momentarily separate, which increases the possibility of welding due to an arc.

[0071] 4 shows the operation of the relay 1 according to this embodiment. 401 shows the state at the time when the facing surface 41 of the card 4 comes into contact with the contact portion 32 of the movable piece 3. In this state, the distance between the center of the movable contact 31 and the contact point P11 between the facing surface 41 and the contact portion 32 is designated as L1. 402 also shows the state in which the movable piece 3 is elastically deformed by the pressure of the card 4, and the movable contact 31 comes into contact with the fixed contact 21 of the fixed piece 2. In this state, the distance between the center of the movable contact 31 and the contact point P11 between the facing surface 41 and the contact portion 32 is designated as L2.

[0072] In the configuration of the relay 1 according to this embodiment, a convex contact portion 32 is provided on the side of the movable piece 3. Therefore, while the movable piece 3 is pressed by the card 4 and elastically deformed, the position where the movable piece 3 and the card 4 come into contact is limited to the contact portion 32. In other words, the distance L1 and the distance L2 are approximately equal.

[0073] Therefore, while the movable piece 3 is pressed by the card 4 and elastically deformed, the pressing force is applied to approximately the same position on the movable piece 3, so it is possible to maintain a substantially constant moment applied to the movable piece 3. Therefore, when the contact pressure between the fixed contact 21 and the movable contact 31 is insufficient, it is possible to suppress the occurrence of welding caused by an arc that occurs when the fixed contact 21 and the movable contact 31 momentarily separate.

[0074] Furthermore, since the fixed contact 21 and the movable contact 31 are made of the contact material of the present invention, they are also excellent in terms of welding resistance from the viewpoint of material. Therefore, it can be said that the relay 1 has a configuration that provides sufficient resistance to inrush currents from the viewpoint of both structure and material, and that allows for miniaturization.

[0075] In other words, the above configuration makes it possible to provide a miniaturizable relay with excellent inrush current resistance, which has not existed in the past. Therefore, the relay 1 can be widely used in, but not limited to, smart meters where miniaturization is strongly required, and lighting applications such as LEDs.

[0076] 4, throughout the entire movable range in which the card 4 presses against the movable piece 3, the movable piece 3 and the card 4 come into contact only at the contact portion 32. In other words, the card 4 and the movable piece 3 do not come into contact at any portion other than the contact portion 32, so that wear at any portion other than the contact portion 32 can be prevented.

[0077] 4 indicates a state in which the card 4 has pressed the movable piece 3 to the greatest extent within the movable range in which the card 4 presses the movable piece 3. In this state, a surface S2 that passes through a contact point P11 where the contact portion 32 and the card 4 are in contact, and is parallel to the movable piece surface 34 of the portion of the movable piece 3 that extends from the movable contact 31 toward the base of the contact portion 32, does not pass through the area occupied by the member that constitutes the movable contact 31.

[0078] 4 shows a state in which the relay 1 is installed so that the normal direction of the movable piece surface 34 is horizontal, in other words, so that the contact portion 32 is located above the movable contact 31. In this case, when the card 4 presses the movable piece 3 all the way in, the contact point P11 where the contact portion 32 and the card 4 are in contact is not located above the area occupied by the members that make up the movable contact 31. This prevents wear powder generated at the contact point P11 from falling onto the movable contact 31, thereby preventing contact failures caused by wear powder.

[0079] 5 is a plan view of the state in which the facing surface 41 of the card 4 and the contact portion 32 of the movable piece 3 are in contact, as viewed from above in FIG. 1. As shown in the figure, the width of the facing surface 41 of the card 4 in a direction perpendicular to the main axis direction AX, i.e., in the horizontal direction (up and down direction in FIG. 5), is shorter than the width of the contact portion 32 in a direction perpendicular to the main axis direction AX, i.e., in the horizontal direction (up and down direction in FIG. 5). With this configuration, the end of the contact portion 32 in the direction perpendicular to the main axis direction AX does not come into contact with the facing surface 41 of the card 4, thereby preventing wear and damage to the facing surface 41.

[0080] In addition, chamfering 411 is applied to both ends of the facing surface 41 of the card 4 in a direction perpendicular to the main axis direction AX, i.e., in the horizontal direction (up and down direction in FIG. 5 ). This configuration prevents the ends of the contact portions 32 in the direction perpendicular to the main axis direction AX from coming into contact with the facing surface 41 of the card 4, thereby preventing wear and damage to the facing surface 41.

[0081] In the example shown in FIG. 5, the chamfering 411 is an arc-shaped R-chamfer, but this is not limited to this and may be, for example, a C-chamfer, which is a linear chamfer at a 45-degree angle.

[0082] Furthermore, when the opposing surface 41 is subjected to the chamfering 411 as described above, the width of the portion of the opposing surface 41 that is inside the chamfering 411 may be shorter than the width of the contact portion 32 in the direction perpendicular to the main axis direction AX.

[0083] Furthermore, the contact portion 32 may be chamfered in a direction perpendicular to the main axis direction AX, i.e., at both ends in the horizontal direction (the up-down direction in FIG. 5 ). If this chamfering is an R-chamfer, the width of the opposing surface 41 in the direction perpendicular to the main axis direction AX may be longer than the width of the contact portion 32 in the direction perpendicular to the main axis direction AX.

[0084] 5, the opposing surface 41 is a gently curved surface when viewed from above, but it may be a completely flat surface. Also, the contact portion 32 is a completely flat surface when viewed from above, but it may be a gently curved surface.

[0085] 6 is a side view showing a state in which the opposing surface 41 and the contact portion 32 of the movable piece 3 are in contact with each other when the movable contact 31 and the fixed contact 21 are in contact. As shown in the figure, within the movable range in which the card 4 presses the movable piece 3, when the movable contact 31 and the fixed contact 21 are in contact, the direction D2 of the force applied by the card 4 to the contact portion 32 is directed toward the fixed end 33 rather than the direction D1 in which the contact portion 32 moves due to the pressing force. This configuration more effectively prevents the fixed contact 21 and the movable contact 31 from momentarily separating when the movable piece 3 is pressed to the fullest extent by the card 4. This prevents welding caused by an arc that occurs when the fixed contact 21 and the movable contact 31 momentarily separate.

[0086] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

[0087] [Summary] The present invention includes the following aspects. <1> A contact material having a material structure in which an oxide of a metal M is dispersed in a matrix made of Ag and / or an Ag alloy, wherein the metal M contains Sn, the metal components of the contact material contain the metal M with the remainder being Ag and unavoidable impurity metals, and the content of the metal M relative to the total weight of all metal components of the contact material is more than 8 wt % and not more than 20 wt %. <2> The contact material according to <1>, wherein the metal M contains Te and / or Bi, and the content of the Te and / or Bi relative to the total weight of all metal components of the contact material is 0.2 wt % or more and 1.0 wt % or less. <3> A relay comprising: a fixed piece fixed to a base; a fixed contact provided on the fixed piece; a movable piece fixed at a fixed end to the base and including an elastically deformable portion; a movable contact provided on the movable piece and arranged opposite the fixed contact; a card that presses the movable piece to elastically deform, connecting the movable contact to the fixed contact; and a drive unit that operates the card by controlling the supply of current to an electromagnet, wherein the movable piece has a contact portion that is convex in a direction facing the card, and the movable piece and the card contact each other at the contact portion, and the fixed contact and the movable contact contain the contact material according to <1> or <2>. <4> The relay according to <3>, wherein the contact portion is provided on the movable piece at a position opposite the fixed end with respect to the movable contact. <5> The relay according to <3> or <4>, wherein the movable piece and the card contact each other only at the contact portion throughout the entire movable range in which the card presses the movable piece. <6> The relay according to any one of <3> to <5>, wherein the convex shape of the contact portion is a curved surface.<7> The relay according to any one of <3> to <6>, wherein, in a movable range in which the card presses the movable piece, when the card presses the movable piece to the fullest extent, a plane that passes through a contact point where the contact portion and the card are in contact and is parallel to a movable piece surface at a portion of the movable piece that extends from the movable contact toward a base of the contact portion does not pass through an area occupied by a member that constitutes the movable contact.<8> The relay according to any one of <3> to <7>, wherein the contact portion has a convex cross section taken along a plane including a main axis direction from the fixed end to the contact portion and a direction in which the contact portion moves when pressed, and a linear cross section taken along a plane normal to the main axis direction, and wherein the width of an opposing surface of the card that faces the contact portion in a direction perpendicular to the main axis direction is shorter than the width of the contact portion in the direction perpendicular to the main axis direction. <9> The relay according to any one of <3> to <8>, wherein the contact portion has a convex cross section taken along a plane including a main axis direction from the fixed end to the contact portion and a direction in which the contact portion moves when pressed, and a linear cross section taken along a plane normal to the main axis direction, and wherein both ends of the opposing surface of the card that faces the contact portion in a direction perpendicular to the main axis direction are chamfered. <10> A relay described in any one of <3> to <9>, wherein, within the movable range in which the card presses against the movable piece, when the movable contact and the fixed contact are in contact, the direction of the force applied by the card to the contact portion is directed toward the fixed end rather than the direction in which the contact portion moves due to the pressing.

[0088] The present invention will be specifically explained below with reference to examples, but the present invention is not limited to these examples.

[0089] Example 1 (Preparation of Contact Material and Manufacturing of Contacts Using the Same) A contact material was prepared containing, as metal M, Sn, In and Bi, or Sn, In and Te, in a matrix of Ag, in the contents shown in Table 1. The contact material was prepared by the internal oxidation method. That is, first, Ag and the metal M shown in Table 1 were melted in a high-frequency melting furnace to produce an ingot. Next, the ingot was cut into individual pieces with sides of 3 mm or less, and then internally oxidized to produce the contact material.

[0090] The internally oxidized pieces were collected and compression molded to form a billet with a diameter of 50 mm. This billet was then hot extruded and subsequently drawn into a wire with a diameter of 1.8 mm, which was then processed using a header machine to produce a rivet-type contact material. In this example, both the movable contact and the fixed contact were rivet contacts with head dimensions of 2.3 mm diameter x 0.4 mm height.

[0091] The contacts thus obtained were incorporated into the relay 1 shown in FIG. 1 as the fixed contact 21 and the movable contact 31, respectively, and their resistance to inrush current was evaluated.

[0092] (Evaluation of resistance to inrush current) TV8 (inrush current 117 A), TV5 (inrush current 78 A), and E-ballast 3 (inrush current 258 A) were selected as ratings for evaluating resistance to inrush current. A tungsten lamp was used as the load. Relays 1 (11 units in total) each incorporating contacts made of the contact materials shown in Table 1 as the fixed contacts 21 and the movable contacts 31 were incorporated into the tungsten lamp and subjected to an electrical endurance life test. The external size of the relay 1 was 5000 mm ３ Therefore, the relay 1 corresponds to a so-called small relay.

[0093] The electrical durability test was conducted as follows: The relay was mounted on a test circuit capable of loading inrush current, and the test conditions were AC 250V, with an opening / closing cycle of 1 second (ON) / 9 seconds (OFF), and various inrush current loads (TV3, TV8, E-ballast 3) were applied to measure the number of openings and closings until failure occurred.

[0094] The contact pressure between the fixed contact 21 and the movable contact 31 was set to 0.4 N or less, and the attraction force of the coil of the driving unit 7 was set to 1.5 N or less.

[0095] The results are shown in Table 1. For TV5 and TV8, a passing rating is given when the number of opening and closing cycles is 25,000 or more. For E-ballast 3, a passing rating is given when the number of opening and closing cycles is 6,000 or more.

[0096]

[0097] The numerical values ​​shown in the composition column in the table represent the content of all metal components in the contact material relative to the total weight, and "%" stands for weight %.

[0098] The contact materials used in Examples 21 to 24 contained more than 8.0 wt. % and 20 wt. % or less of Sn and In as the metal M, and correspond to the contact materials of the present invention. They did not contain Te or Bi. These contact materials exhibited inrush current resistance that passed all of the TV5, TV8, and E ballast tests.

[0099] The contact materials used in Examples 25 to 31 contained, as the metal M, Sn and In, and Te or Bi in a total amount of more than 8.0 wt % and not more than 20 wt %, and correspond to the contact materials of the present invention. The content of Te or Bi was 0.1 wt % or 1.1 wt %. These contact materials did not meet the pass criteria for TV8 and E-ballast, but showed pass-level inrush current resistance for TV5.

[0100] The contact materials used in Examples 1 to 20 contained, as the metal M, Sn and In, and Te or Bi, in a total amount of more than 8.0 wt % and not more than 20 wt %, and correspond to the contact materials of the present invention. The Te or Bi content was 0.2 wt %, 0.5 wt %, or 1 wt %. These contact materials exhibited inrush current resistance that was acceptable for all of TV5, TV8, and E-Ballast, and the results for TV8 and E-Ballast 3 were significantly better than those of Examples 21 to 24, which had the same total content of metal M.

[0101] Comparing the results of Examples 1 to 20 with the results of Examples 25 to 31, it can be seen that when the condition that the Te or Bi content is 0.2 wt % or more and 1.0 wt % or less is met, the inrush current resistance is significantly improved for all of TV5, TV8 and E ballast 3 compared to when this condition is not met.

[0102] The contact materials used in Comparative Examples 1 to 3 had a metal M content of 21 wt %, and do not fall under the category of contact materials of the present invention. Furthermore, the contact materials used in Comparative Examples 4 to 6 had a metal M content of 8 wt % or less, and do not fall under the category of contact materials of the present invention. The results of Comparative Examples 1 to 3, 5, and 6 show that when the requirement that the metal M content be more than 8 wt % and not more than 20 wt % is not met, resistance to inrush current is insufficient even if the Te or Bi content is 0.2 wt % or more and 1.0 wt % or less.

[0103] The present invention can be utilized in the manufacture of a relay that has excellent inrush current resistance and can be made smaller.

[0104] DESCRIPTION OF SYMBOLS 1 Relay 2 Fixed piece 3 Movable piece 4 Card 5 Base 6 Armature 7 Drive unit 21 Fixed contact 31 Movable contact 32 Contact part of movable piece 33 Fixed end of movable piece 34 Movable piece surface at part where movable piece extends from movable contact towards base of contact part 41 Opposing surface of card with respect to contact part 42 Fixed end of card S2 Surface parallel to movable piece surface at part where movable piece extends from movable contact towards base of contact part

Claims

1. A contact material having a material structure in which an oxide of metal M is dispersed in a matrix made of Ag and / or an Ag alloy, said metal M including Sn, said metal components of said contact material including metal M with the remainder being Ag and unavoidable impurity metals, and the content of said metal M relative to the total weight of all metal components of said contact material is more than 8 wt% and not more than 20 wt%.

2. The contact material according to claim 1, wherein the metal M includes Te and / or Bi, and the content of Te and / or Bi relative to the total weight of all metal components of the contact material is 0.2% by weight or more and 1.0% by weight or less.

3. A relay comprising: a fixed piece fixed to a base; a fixed contact provided on said fixed piece; a movable piece fixed at a fixed end to said base and including an elastically deformable portion; a movable contact provided on said movable piece and arranged opposite said fixed contact; a card that presses said movable piece so as to elastically deform, thereby connecting said movable contact to said fixed contact; and a drive unit that operates said card by controlling the flow of electricity to an electromagnet, wherein said movable piece has a contact portion that is convex in a direction facing said card, and said movable piece and said card contact each other at said contact portion, and said fixed contact and said movable contact contain the contact material according to claim 1 or 2.

4. The relay according to claim 3, wherein the contact portion is provided on the movable piece at a position opposite the fixed end with respect to the movable contact.

5. The relay according to claim 3, wherein the movable piece and the card are in contact only at the contact portion throughout the entire movable range in which the card presses against the movable piece.

6. The relay according to claim 3, wherein the convex shape of the contact portion is a curved surface.

7. A relay as described in claim 3, wherein, within the movable range in which the card presses against the movable piece, when the card presses the movable piece to the farthest extent, a plane that passes through the contact point where the contact portion and the card are in contact and is parallel to the surface of the movable piece at the portion of the movable piece that extends from the movable contact toward the base of the contact portion does not pass through the area occupied by the member that constitutes the movable contact.

8. A relay as described in claim 3, wherein the cross section of the contact portion taken along a plane including the main axis direction from the fixed end to the contact portion and the direction in which the contact portion moves when pressed is convex, and the cross section taken along a plane having the main axis direction as its normal direction is linear, and the width of the opposing surface of the card that faces the contact portion in the direction perpendicular to the main axis direction is shorter than the width of the contact portion in the direction perpendicular to the main axis direction.

9. A relay as claimed in claim 3, wherein the contact portion has a convex cross section along a plane including the direction of the main axis from the fixed end to the contact portion and the direction in which the contact portion moves when pressed, a linear cross section along a plane normal to the main axis direction, and both ends of the opposing surface of the card that faces the contact portion in a direction perpendicular to the main axis direction are chamfered.

10. A relay as described in claim 3, wherein, within the movable range in which the card presses against the movable piece, when the movable contact and the fixed contact are in contact, the direction of the force applied by the card to the contact portion is directed toward the fixed end rather than the direction in which the contact portion moves due to the pressure.

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