JP2005294126A - Dc relay - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC relay using a Cd-free contact material without causing a problem of toxicity, and capable of securing stability of a brazing property and abrasion resistance. <P>SOLUTION: This DC relay has a contact pair having contact touching parts opening and closing with respect to each other. Each contact touching part contains 1-9 mass% of Sn and is formed of an Ag alloy where Cd as an impurity is less than 1 mass%. The average hardness at least on a surface of the contact touching part is 150 mHv or higher according to micro Vickers standard regulated by JIS. When the contact contacting part having this chemical constituents is used, it does not substantially contain Cd, whereby the problem of toxicity can be avoided, and its property is stabilized by restricting the average hardness on its surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a direct current relay. In particular, the present invention relates to a DC relay using a contact material that can secure brazing properties and stability of wear characteristics.

  In recent years, high voltage (about 300V) vehicles such as hybrid vehicles and fuel cell vehicles have been developed due to environmental problems. These automobiles are provided with a control circuit comprising a high-voltage main battery and a high-voltage circuit. In addition, since the main battery is a DC high voltage, it is necessary to disconnect the battery from the control circuit in the event of an accident, and a DC relay with a mechanical contact is provided between the battery and the control circuit.

  These relays have a very large arc generated when the DC high voltage is cut off, so the breaking speed is very slow and it is very difficult to cut off in a short time. Therefore, conventionally, there is a structure (see, for example, Patent Document 1) in which a magnet is installed in the arc generating portion and the arc is stretched by Lorentz force.

  The DC relay of Patent Document 1 includes two contact pairs, and a pair of magnets is arranged so as to sandwich the contact pairs with respect to each contact pair so as to be orthogonal to a line connecting the contact pairs. In the relay of Patent Document 1, the pair of magnets are arranged so that the facing magnetic pole faces are different. Furthermore, in Patent Document 1, these contact pairs are provided with contacts so that a current flows in series when connected.

  Therefore, in Patent Document 1, when each contact pair is in a non-contact state, an arc generated between the contacts is on a line connecting the two contact pairs and opposite to the adjacent contact pair (outside). It is designed to be distorted.

  On the other hand, as an electrical contact material such as a breaker, an Ag alloy in which an oxide such as Cd, Sn, or In is dispersed, or a Cd-free Ag alloy in which an oxide such as Sn or In is dispersed is used.

Japanese Patent No. 3321963

  However, in the relay shown in the conventional patent document 1, a pair of magnets are installed in each contact pair, and the arc is extended to the outside of the contact pair on the line connecting the two contact pairs by the action of the magnetic field. Therefore, a space for securing the amount of arc extension necessary for immediate interruption of the relay is required.

  In addition, since a pair of magnets having a magnetic force corresponding to the amount of arc stretching is provided for each contact pair, the number of magnets increases. As a result, there is a problem that the entire relay becomes large.

  Furthermore, since a pair of magnets is provided for each contact pair, the number of magnets increases and the assembly process takes time, resulting in high costs.

  In addition, since a hybrid vehicle or the like employs a system that converts kinetic energy into electric energy and charges a battery during deceleration, a reverse current (regenerative current) may be generated in the relay. Therefore, it is necessary to cut off the relay even when excessive reverse current flows.

  However, in the relay structure of Patent Document 1, when the relay is cut off when a reverse current is generated, the arc generated between the contacts is distorted between the two contact pairs by the Lorentz force of the magnet. In this case, each arc is stretched toward the adjacent contact pair, and the arcs are connected to each other, resulting in a problem that immediate interruption is not possible.

  Furthermore, regarding contact materials, Ag alloys containing Cd compounds have optimal properties for electrical contacts, but Cd compounds contained in contact materials have a toxicity problem. On the other hand, although Cd-free Ag alloys do not contain Cd, there is no problem of toxicity, but they have very low properties compared to materials containing Cd. For example, there is a drawback in that contact stability tends to progress because the stability of the brazing property is low and the contact resistance itself is poor.

  Accordingly, a main object of the present invention is to provide a direct current relay that uses a Cd-free contact material that is free from toxicity problems and that is secured in terms of brazing stability and wear resistance.

  Another object of the present invention is to provide a direct current relay capable of interrupting a direct current high voltage in a short time even at a reverse current while minimizing the number of magnets as much as possible and reducing the size with a simple structure.

  The present invention achieves the above object by defining the average hardness of contact surfaces that are in contact with each other.

  The DC relay of the present invention is a DC relay including a contact pair having contact contact portions that open and close each other. The contact point contact portion is made of an Ag alloy containing 1 to 9% by mass of Sn and having Cd as an impurity of less than 1% by mass. And at least the average hardness at the surface of the contact portion is 150 mHv or more based on the micro Vickers standard defined in JIS.

  If the contact contact portion having the above chemical component is used, the problem of toxicity can be avoided because Cd is not substantially contained. Further, by using the chemical component as a contact contact portion and limiting the average hardness on the surface thereof, the physical properties can be stabilized, and the above-described joining properties and the like can be improved and stabilized.

(Contact material and configuration)
The chemical composition of the contact portion used in the relay of the present invention is made of an Ag alloy containing 1 to 9% by mass of Sn. The Sn content of 1 to 9% by mass is less than 1% by mass, resulting in large variations in insulation characteristics and other characteristics, and other characteristics that should basically be provided as Cd-free contact points. It is because it deteriorates. On the other hand, when the content exceeds 9% by mass, it becomes difficult to manufacture the contact. The Sn content is preferably 2 to 7% by mass. In addition, from the viewpoint of Cd-free, the Cd content is preferably less than 0.01% by mass, and may not substantially contain Cd.

  This contact portion is selected from the group consisting of In, Sb, Ca, Bi, Ni, Co, Zn, Te, Cr and Pb for the purpose of improving various performances in addition to the basic components Ag and Sn. And at least one element. In particular, when In is contained in an amount of 1 to 9% by mass, the contact contact portion can be easily produced. The In content is preferably 3 to 8% by mass. These component elements such as Sn and In, including the component elements described later, are usually dispersed as compounds in the Ag matrix, particularly in the form of oxides.

  Other additive components and their desirable contents are in mass% units, Sb is 0.05-2%, Ca is 0.03-0.3%, Bi is 0.01-1%, Ni is 0.02-1.5%, Co is 0.02-0.5% , Zn is 0.02 to 8.5%, and Pb, Te and Cr are all 0.05 to 5%. When these component elements are included, if the content is out of the above range, the welding resistance and temperature characteristics may be lowered, and if the upper limit of the above range is exceeded, productivity may be lowered.

Even elements other than those described above can be included in minute amounts within the scope of the object of the present invention. As such elements, for example, Ce, Li, Cr, Sr, Ti, Te, Mn, AlF ₃ , CrF ₃ , and CaF ₂ are all 5% or less, and Ge and Ga are 3% or less in the same mass% unit. , Si can be included in a range of 0.5% or less, and Fe and Mg can be included in a range of 0.1% or less, respectively.

  By using the contact contact portion having the above chemical composition and setting the average hardness of the surface to 150 mHv or more on the basis of micro Vickers, it is possible to improve insulation characteristics and variation characteristics. Insulation properties are a frequent problem with Cd-containing contact materials, and even Cd-free contact materials tend to be slightly better than Cd-containing contact materials. By setting the average surface hardness to 150 mHv or more according to the present invention, it is possible to improve the problem relating to the insulation characteristics of the Cd-free contact material. In addition, Cd-free contact materials are often poorly consumable, which has been a major impediment to practical use. However, this consumptiveness can also be solved by increasing the average hardness of the contact surface. Can do.

  In general, Cd-free contact materials have a large variation in physical properties, so that, for example, the bonding conditions are not stable even in the bonding process, and the bonding strength with the base metal made of Cu or its alloy is not stable. There was a problem of drop-off between the contacts and the Cu base metal. In some cases, the variation in the bonding strength also causes the variation in the wear characteristics. In addition, when the wear characteristics are poor, the contact components scatter to the periphery due to a large current load, which causes the insulation characteristics to deteriorate.

  In the relay of the present invention, physical properties are stabilized by using a contact point contact portion having an average surface hardness of 150 mHv or more, and the above-described bonding property is improved and stabilized. As a result, the characteristics of the contacts are stabilized, and there is an advantage that products with abnormally low brazing strength are hardly generated. As described above, in order to improve not only the insulating properties and consumability but also the bonding properties and other characteristics, the higher the average hardness of the surface, the better, preferably 160 mHv or more, more preferably 180 mHv or more, and even more preferably. Is over 190mHv. In particular, when it exceeds 220 mHv, there is virtually no variation in characteristics. The micro Vickers hardness is desirably measured with a load of 10 g or 25 g.

  In the contact contact portion used in the relay of the present invention, the average hardness of the surface may be 150 mHv or more. Therefore, this includes not only the case where the average hardness of the surface is 150 or more and the internal average hardness of less than 150 mHv, but also the case where the surface has the same hardness over the entire area in the inner direction of the contact point. Further, the surface hardness may be distributed. That is, a part of the surface, for example, a central part may have an unintentionally low content of a dispersion component such as Sn, that is, a part with low hardness, but even in such a case, the average hardness of the surface It should be 150mHv or more. The “average hardness” is an arithmetic average obtained by measuring the micro Vickers hardness specified in JIS at an arbitrary point on the surface of the contact. The number of measurement points is desirably 30 or more.

  Further, a desirable form of the contact point contact portion includes a two-layer structure including a surface layer having an average hardness of 150 mHv or more and an inner layer having a hardness lower than that of the surface layer. In this case, the thickness of the surface layer is preferably 10 μm or more, and more preferably in the range of 20 to 120 μm. If the thickness of the surface layer is less than 10 μm, it is difficult to obtain the above-described improvements in various characteristics, and an excessively thick layer is not preferable in terms of manufacturing cost. The thickness of the surface layer is a value obtained by arithmetically averaging the thickness of the surface layer by checking the thickness of the surface layer at five points in a direction parallel to the contact surface with an optical microscope on a cross section perpendicular to the contact surface. Note that the internal hardness of an Ag alloy in which Sn oxides obtained by a normal manufacturing method are dispersed is 145 mHv at the highest.

  As a method of controlling the hardness of the surface layer and the inner layer, there is a method of changing the chemical composition of both. For example, by increasing the Sn content in the surface layer as compared with the inner layer, the hardness of the surface layer can be reliably increased as compared with the inner layer. However, in the present invention, the case where the chemical composition of the surface layer and the inner layer is the same and the hardness of the surface layer is higher than that of the inner layer is also included. As described above, the reason why the hardness levels are different while the chemical composition of the surface layer and the inner layer is the same is that each microstructure is controlled. A method for controlling the hardness by controlling such a fine structure will be described in detail in connection with a method for manufacturing a contact contact portion described later. Of course, for example, those having a lower Sn concentration in the surface layer are also included in the contact contact portion used in the relay of the present invention.

  The contact contact portion described above needs to be connected to another member such as a base metal in order to be incorporated into a breaker, for example, depending on the application. In that case, in order to facilitate connection with other members such as a base metal, a thin connection layer made of metal such as pure Ag or brazing material is provided on the back surface opposite to the surface of the contact contact portion. Can do. This connection layer may be in the same form as a metal layer usually provided for this type of purpose. In addition, joining of the contact contact portion and other members such as a base metal is usually performed through the connection layer as described above, but the Ag alloy to be the contact contact portion is directly generated on the base metal or the like, Alternatively, it can be molded integrally with the base metal.

  7 to 9 show typical examples of contact contact portions used in the relay of the present invention. The contact contact portion in FIG. 7 is a typical example including an inner layer 110 and a surface layer 120 formed only on the front surface side, and a connection layer 130 is provided on the back surface side of the inner layer 110. In the contact contact portion of FIG. 8, the surface layer 120 is provided so as to surround all of the front surface side, the back surface side, and the side surface of the inner layer 110. Further, in the contact contact portion of FIG. 9, the surface layer 120 is provided so as to surround the surface side and the side surface of the inner layer 110. 7 to 9, a connection layer 130 is provided on the back surface of the contact.

  Next, the manufacturing method of the contact contact part used with this invention relay is demonstrated. Contact contacts with a hard surface can be made by powder metallurgy. For example, fine oxides or other compounds such as Sn and In, or Sn and In compounds that become oxides or other new compounds by heating, and Ag powder are mixed and mixed in a predetermined composition. Then, if necessary, heat treatment is performed. In the same manner, mixed powders having different chemical compositions, that is, mixing ratios, are prepared, and then these two types of mixed powders are laminated, formed into a preform, and then sintered. As the post-sintering processing, various plastic processing such as hot extrusion, hot or cold roll rolling, hot forging, and the like can be applied. If necessary, a heat treatment, a step of adjusting the shape, and the like can be appropriately performed after rolling. A contact having a hard surface layer can be obtained by devising the composition and fineness of the raw material powder, post-sintering processing and heat treatment conditions, and various characteristics of the contact can be controlled.

  In addition, after the inner layer of the contact contact portion as the base is made by powder metallurgy or melting method, the surface layer is sprayed on it, thick film deposition (CVD etc.), metallurgical various such as thick film printing / baking It can also be formed by various means. Furthermore, a surface layer and an inner layer separately prepared in advance can be bonded. In this case, various means such as diffusion bonding by hot isostatic pressing and hot extrusion can be applied. Furthermore, it is also possible to intentionally control the microstructure of each layer by applying a heat treatment, and to change it to a desired hardness.

  Further, when the contact contact portion used in the relay of the present invention is manufactured by a melting method, for example, after first melting and casting so as to have the chemical composition of the surface layer and the inner layer, and roughly rolling the obtained ingot , Two kinds of rolled materials are bonded together by hot pressing. At that time or after that, if necessary, a thin connection layer such as the above pure Ag is pressure-bonded. This is further rolled to form a hoop of a predetermined thickness, and then the hoop is punched (or further shaped) to form an Ag alloy composite material having a size close to the final shape, and this material is internally oxidized to produce Sn, In Convert metal components such as to oxides. Prior to melting and casting, compounds other than the oxides of the component elements can be included.

  As a method other than laminating as described above, even if one kind of rolled material is used, the microstructure is consciously controlled by adding a heat treatment and a step of adjusting the shape appropriately after rolling, and the surface layer The hardness can be increased, and the material properties and levels of each layer can be changed. Also, as part of the heat treatment, one of the methods is to set the oxidation temperature at the initial stage of oxidation to a low temperature of about 600 ° C., hold it at that low temperature, for example, for 2 hours, and then oxidize at a high temperature of 750 ° C. Of course, in order to obtain a hard alloy, it may be held at a lower temperature for a longer time, or in some cases until oxidation is completed.

  In addition to the above, the means for controlling the hardness of the contact point contact portion includes, for example, the following method. A method of preparing a composite contact by the above-mentioned method, rapidly heating / cooling only the surface layer, and making the residual stress of the surface layer larger than that of the inner layer, or a method of performing work hardening by applying shot blasting to the surface There is. Moreover, after performing hot rolling and cold rolling in addition to heat treatment and so-called thermomechanical processing (thermal processing treatment) on the Ag alloy plate, the temperature is controlled and internal oxidation is performed, and the surface layer is formed from the internal layer. There is also a method of increasing the hardness of the surface by precipitating fine oxide particles.

  Further, in the method of laminating the surface layer and the inner layer, and if necessary, the bonding layer by the rolling process described above, the surface layer and the inner layer have the same chemical composition, and the forging ratio of the surface layer and the inner layer is made different. There is a method in which both layers have the same chemical composition and different hardness. The above hardness control means is effective particularly when the surface layer and the inner layer have the same chemical composition.

(Relay structure)
The above contact contact portions are arranged in the vicinity of the contact surface of the contact pair that opens and closes. The structure of the DC relay to which the contact contact portion is applied is not particularly limited as long as it has a contact pair that can be cut off and conducted by opening and closing. The number of contact pairs may be at least a pair, and a plurality of pairs may be used.

  Examples of suitable DC relay configurations include the following. That is, at least one is a movable contact, and a plurality of contact pairs that open and close each other are provided. Each contact pair has a pair of contact contact portions. And while arrange | positioning a some magnet on one straight line, the said contact pair is arrange | positioned between these magnets so that it may be on the same line. The magnets are arranged so that the opposing magnetic pole surfaces are all different magnetic poles. By arranging the magnets in this way, the arc generated between the contacts when the relay is interrupted can be distorted in the direction intersecting the straight line.

  The DC relay can have two or more contact pairs. For example, when two contact pairs are provided and the contact pairs can be connected in series, one side of the contact pair opening / closing direction is an input contact and an output contact, and the other side of the contact pair opening / closing direction is conductive, A connection contact that connects the input contact and output contact in series.

  Each of the input contact and the output contact has a contact contact portion, and an external terminal is connected to these contacts. The connecting contact can be formed in, for example, a U shape, a] shape, or a flat plate shape. In the case of a U-shape or] shape, the projecting end faces become contact portions that come into contact with the input contact or the output contact. In the case of a flat plate shape, the input contact and the output contact are brought into contact with the flat surface of the flat plate.

  In this case, a pair of contact pairs is constituted by the contact portion of the input contact and one contact portion of the connection contact, and a pair of contact pairs is constituted by the contact portion of the output contact and the other contact portion of the connection contact.

  The connection contact connects the input contact and the output contact with the connection contact at the time of contact (conduction), so that the input contact, the connection contact, and the output contact are connected in series at the time of connection.

  Further, three magnets are arranged on the line connecting the input contact and the output contact so as to sandwich the input contact and the output contact. These magnets are arranged so that the opposing magnetic pole surfaces are different magnetic poles.

  When the contact pairs can be connected in series, when each contact is in contact, when current flows from the input contact, current flows to the output contact via the connection contact. And when each contact is separated, all the contacts are in a non-contact state, and an arc is generated between the contacts facing each other, but since each contact is connected in series, the breaking voltage is divided, The arc can be extinguished.

  Moreover, in the present invention, when the contact is interrupted, the arc generated between the contacts by the magnetic field of the magnet is blown away so as to be distorted in the direction intersecting the line. At this time, for example, as shown in FIG. 1, when the respective contacts can be connected in series, the current flows as shown in FIG. And a magnetic force line always arises in the same direction. As a result, according to Fleming's left-hand rule, the arc is distorted by the Lorentz force so as to extend in a direction perpendicular to the line connecting the contact pair and the magnet, as shown in FIG.

  By providing a magnet in this way, it is possible to divide the breaking voltage and to increase the arc voltage in a shorter time by blowing off the arc by the magnet and to cut off the relay in a shorter time.

  In addition, since the arc energy is consumed by extending the arc by the magnet while performing the voltage interruption by the multi-contact, in the present invention, it is not necessary to secure the predetermined arc extension amount necessary for voltage interruption as in the prior art. The magnetic force of the magnet used can be made smaller than before, and the magnet can be made smaller.

  Furthermore, in the present invention, since the arc stretching direction intersects the straight line connecting the contact pairs, even if a reverse current such as regenerative energy occurs, the arcs are not connected, and the reverse current It can respond enough.

  In addition, since a contact pair is provided between a plurality of magnets, it is not necessary to provide a pair of magnets for one contact pair, so that the number of magnets to be used can be reduced compared to the conventional Patent Document 1. This can reduce the cost.

  The DC relay of the present invention may be configured such that the contact pairs can be connected in series, or the contact pairs may be connected in parallel.

  When the contact pair is configured to be connectable in series, the voltage can be interrupted in a shorter time by dividing the voltage between the contacts at the time of disconnection. As a result, it is possible to suppress contact damage due to arc current by reducing the voltage applied between the contacts.

  Further, when the contact pairs are configured to be connectable in parallel, current can be shunted, and damage to the contact due to arc current can be suppressed by reducing the current flowing through one contact.

  Furthermore, in the present invention, it is preferable that the surface of the contact point contact portion is formed such that the length in the linear direction is shorter than the length in the direction orthogonal to the straight line.

  For example, as described above, the input contact and the output contact are arranged on the same straight line, and the connection contact is arranged on this line so as to overlap the input contact and the output contact so as to be on the same line in plan view. To.

  At this time, a contact contact portion is formed on each contact to be brought into contact with the other contact, and the length of the surface of the contact portion in the linear direction connecting each contact is shorter than the length in the direction perpendicular to the linear direction. To form.

  When the length of the surface of the contact portion is shorter than the length in the direction perpendicular to the linear direction, the shape of the surface is formed into a flat shape such as an ellipse, an ellipse, or a rectangle. , That the minor axis direction of the surface is the linear direction.

  When arranging a plurality of contact pairs on the same line, if the number of contacts increases, the entire relay may become larger in the linear direction. In particular, in a DC relay, a solenoid is often used to move the movable contact, and the size of the solenoid is determined when an off-the-shelf product is used. It is preferable not to protrude from the cross-sectional area.

  Therefore, by forming the shape of the surface of the contact point contact portion so that the length in the linear direction is shorter than the length in the direction orthogonal to the linear direction, while ensuring the size of the surface of the contact point contact portion sufficiently An increase in length in the linear direction, that is, in the contact arrangement direction of the relays can be minimized.

  When a solenoid is used in a state where a plurality of contact pairs are arranged in a line, an effective space is generated in the area of the cross section of the solenoid in a direction orthogonal to the linear direction. In the present invention, the volume of the entire relay can be reduced by extending the contact surface toward the effective space and shortening the length in the arrangement direction.

  Furthermore, when a solenoid is used for the relay, for example, an effective space is generated in the direction orthogonal to the linear direction as described above. Therefore, this effective space can be used as an arc stretching space. Need not be secured separately.

  Here, various driving sources can be used to open and close the contacts. A motor can be used for the rotary drive source, and a solenoid or cylinder can be used for the linear drive source. In the case of using a rotary drive source, the contact is driven via a conversion mechanism that converts rotational motion into reciprocating motion. When a linear drive source is used, the contact is driven by connecting the linear drive source to the contact.

  In the present invention, one of the contact pairs to be opened and closed may be a movable contact, the other may be a fixed contact, or both may be opened and closed as a movable contact.

  As described above, according to the DC relay of the present invention, the following effects can be obtained.

  By using a contact portion made of a Cd-free Ag alloy, the toxicity problem can be avoided. Further, by specifying the surface hardness of the contact surface portion with the material of this chemical component, it is possible to provide a direct current relay in which the physical properties are stabilized and the insulating characteristics and the bonding properties are stabilized.

  Since the arc generated between the contacts of the contact pair at the time of interruption is distorted in the direction intersecting the straight line that is the direction of arrangement of the magnet and contact pair, voltage interruption of multiple contacts by multiple contact pairs and blowing off of the arc by the magnet The relay can be cut off in a short time. Moreover, since the arc extending direction intersects the straight line that is the contact arrangement direction, even if a reverse current such as regenerative energy is generated, the arcs are not connected to each other, and the reverse current is sufficiently supported. be able to.

  Furthermore, when the surface of the contact contact portion is formed so that the length in the contact arrangement direction (linear direction) is shorter than the length in the direction perpendicular to the linear direction, the size of the surface of the contact contact portion is large. The increase in the length of the relays in the contact arrangement direction can be suppressed to a minimum while ensuring sufficient.

  In addition, when the contact pairs can be connected in series when energized, the voltage between the contacts is divided to suppress the generation of arc and to realize the interruption in a short time.

  In addition, when the contact pairs can be connected in parallel when energized, the current can be shunted, and the contact current can be prevented from being damaged by reducing the current flowing through one contact.

  In particular, when the relay of the present invention is used as a relay for turning on / off a high voltage circuit in a high voltage (about 300 V) vehicle such as a hybrid vehicle, the relay of the present invention is compact, so that it has a limited space. Can be used effectively.

  Embodiments of the present invention will be described below.

  1 and 2 are schematic configuration diagrams showing a basic configuration of the relay according to the first embodiment of the present invention. FIG. 1 shows a contact state in contact, and FIG. 2 shows a contact non-contact state. Show. 3 and 4 are diagrams showing a specific configuration of the relay according to the first embodiment. FIG. 3 is a longitudinal sectional view, and FIG. 4 is a transverse sectional view.

  5 and 6 are schematic configuration diagrams showing a basic configuration of the relay according to the second embodiment of the present invention. FIG. 5 shows a contact state in contact, and FIG. 6 shows a contact in a non-contact state. Indicates the state.

(First embodiment)
As shown in FIG. 3, the DC relay according to the first embodiment includes an input contact 21 and an output contact 22 as fixed contacts, a connection contact 3 as a movable contact, and a contact drive mechanism 4 in a casing 1. Yeah.

  The input contact 21 and the output contact 22 include contact portions 21a and 22a that are brought into contact with the connection contact 3, and terminal connection portions 21b and 22b, and external terminals are connected to the terminal connection portions 21b and 22b.

  The connection contact 3 has a U-shaped cross section, and the flat portions at both ends of the U-shape serve as contact portions 31. The contact portion 31 of the connection contact 3 is brought into contact with the contact portion 21a of the input contact 21 and the contact portion 22a of the output contact 22.

  In the present embodiment, the contact portion 21a of the input contact 21 and one contact portion 31 of the connection contact 3 form one contact pair, and the contact portion 22a of the output contact 22 and the other contact portion 31 of the connection contact 3 Is another contact pair. Each of these contact portions 21a, 22a, 31 is made of an Ag alloy containing 1 to 9% by mass of Sn and having Cd as an impurity of less than 1% by mass, and the above-described configuration shown in FIGS. , A structure having a surface layer and a connection layer (not shown in FIG. 3). Moreover, the average hardness of the surface of this contact part is 150 mHv or more on a micro Vickers basis.

  Then, the input contact 21, the connection contact 3, and the output contact 22 are arranged so as to be positioned on the same straight line. Specifically, the contact portion 21a of the input contact 21 is brought into contact with one contact portion 31 of the connection contact 3, and the contact portion 22a of the output contact 22 is brought into contact with the other contact portion 31b of the connection contact 3. When in a state, the contact pairs in the contact state are arranged on the same straight line.

  As shown in FIG. 1, each contact is arranged in this way and brought into contact with the contact portion of each contact so that each contact is connected in series from the input contact 21 to the output contact 22 via the connecting contact 31. Is done.

  Moreover, as shown in FIGS. 1 and 2, the contact portion 21a of the input contact 21 and the contact portion 22a of the output contact 22 are formed in the shape of an ellipse as the contact surface to be brought into contact with the contact portion of the connecting contact 3. ing. The contact portions 21a and 22a are provided so that the minor axis direction of the ellipse of the contact surface is the arrangement direction of the contact points (the linear direction). The input contact 21 and the output contact 22 use cylindrical metal blocks having contact surfaces of the contact portions 21a and 22a having an oval shape.

  As shown in FIG. 3, the connecting contact 31 is reciprocated in the contact opening / closing direction by the contact driving mechanism 4. The contact drive mechanism 4 opens and closes the contacts, and the connection contact 31 is brought into contact or non-contact with the input contact 21 and the output contact 22.

  The contact drive mechanism 4 will be specifically described. The contact drive mechanism 4 includes a spring 41 and a solenoid 42. The spring 41 is disposed between the connection contact 3 and the solenoid 42. Then, the spring 41 is inserted into the drive shaft 43 of the solenoid 42. The spring 41 biases the connecting contact 3 in a direction away from the input contact 21 and the output contact 22, that is, in a contact opening direction.

  The solenoid 42 reciprocates the connection contact 3 in the contact opening / closing direction, and includes a drive shaft 43 whose one end is fixed to the connection contact 3 and a shaft operating unit 44 that reciprocates the drive shaft 43 in the contact opening / closing direction. Have. One end side of the drive shaft 43 is fixed at an intermediate position of the connecting contact 3, and the other end side is inserted into an insertion hole (not shown) provided in the shaft operating portion 44.

  The shaft actuating unit 44 is configured to move the drive shaft 43 in a direction of pushing out from the insertion hole (contact opening direction) when an electric current flows and is in an ON state. That is, when the shaft actuating portion 44 is in the ON state, the drive shaft 43 is moved against the spring force of the spring 41 in the direction in which the connection contact 3 is brought into contact with the input contact 21 and the output contact 22 (contact closing direction).

  When the shaft operating portion 44 is turned off, the extended spring 41 returns, and the drive shaft 43 moves in a direction away from the input contact 21 and the output contact 22 (contact opening direction) by the spring force of the spring 41. .

  Then, the connecting contact 3 reciprocates as the drive shaft 43 of the solenoid 42 moves. When the connection contact 3 moves in the contact closing direction, the contact portion 31 of the connection contact 3 simultaneously contacts the input contact 21 and the contact portions 21a and 22a of the output contact 22.

  When the connection contact 3 moves in the contact opening direction, the contact portion 31 of the connection contact 3 is simultaneously separated from the contact portions 21a and 22a of the input contact 21 and the output contact 22. Thus, the contact driving mechanism 4 opens and closes the connection contact 3 with respect to the input contact 21 and the output contact 22.

  Then, a DC power supply is connected to the terminal connection portion 21b of the input contact 21 via a terminal (not shown), and energization / interruption is performed by the contact / contact of each contact.

  In the present embodiment, three plate-like permanent magnets 5 are provided in the casing 1. The permanent magnet 5 is disposed between the input contact 21 and the output contact 22 and outside the input contact 21 and the output contact 22.

  Further, as shown in FIGS. 1 and 2, the permanent magnet 5 is arranged on the same straight line as the line on which the contact pair is arranged so that one pole (for example, N pole) is located on the same side. These permanent magnets 5 apply a magnetic field between the contact portion 21a of the input contact 21 and one contact portion 31 of the connection contact 3, and between the contact portion 22a of the output contact 22 and the other contact portion 31 of the connection contact 3. I have to. Due to the magnetic field of the permanent magnet 5, when the contacts are interrupted, the arc 100 generated between the contacts is stretched and distorted by the Lorentz force.

  In this embodiment, during contact energization, current flows from the input contact 21, and current flows in series to the connection contact 31 and the output contact 22. And in the state shown in FIG. 2, the permanent magnet 5 is arrange | positioned so that a magnetic force line may go from left to right. Therefore, according to Fleming's left-hand rule, the Lorentz force is generated alternately in the forward direction and in the backward direction in FIG. 2, and the arc 100 generated when the contact is interrupted is alternately distorted back and forth.

  Next, energization / interruption of the contacts will be described. When energizing with the contacts closed, the connecting contact 3 is closed and the connecting contact 3 is brought into contact with the input contact 21 and the output contact 22 to establish conduction (state shown in FIG. 1).

  Further, when the two contacts are opened to be interrupted, the connecting contact 3 is opened and the connecting contact 3 is separated from the input contact 21 and the output contact 22 to be interrupted (state shown in FIG. 2).

  At the time of this interruption, an arc 100 is generated between the contacts, but the arc 100 is distorted in the above-described direction by the magnetic field of the permanent magnet 5.

  In the embodiment, since the two contact pairs are connected in series, the arc can be extinguished by dividing the breaking voltage, and the arc can be extinguished by extending the arc 100 by the magnetic field. Therefore, the voltage can be cut off in a short time. In addition, a very compact DC relay can be realized. Further, since the contact points are arranged in series to divide the cut-off voltage, the durability of the contact points can be improved.

  In addition, since the extending direction of the arc is alternately different along the arrangement direction of the contacts and the magnets, even if a reverse current such as regenerative energy is generated, the arcs are not connected to each other, and the reverse current is sufficiently supported. be able to.

(Second embodiment)
In the first embodiment, a DC relay that can connect contact pairs in series when energized has been described. In the present embodiment, the contact pairs can be connected in parallel when energized.

  As shown in FIGS. 5 and 6, the DC relay according to the second embodiment includes an input contact 6 serving as a fixed contact and an output contact 7 serving as a movable contact. Both the input contact 6 and the output contact 7 have a substantially U-shaped cross section, and the flat portions at both ends of the U-shape are the contact portions 61 and 71. Since these contact points have two contact portions 61 and 71, the two contact portions 61 of the input contact 6 are brought into contact with the two contact portions 71 of the output contact 7 facing each other. The contact portions 61 and 71 also have the same composition and structure as in the first embodiment.

  In the present embodiment, one contact portion 61 of the input contact 6 and one contact portion 71 of the output contact 7 form one contact pair, and the other contact portion 61 of the input contact 6 and the other contact portion of the output contact 7 71 is another contact pair.

  Then, the input contact 6 and the output contact 7 are arranged so that the respective contact portions 61 and 71 are located on the same straight line in the contact state. As shown in FIG. 5, each contact pair is connected in parallel from the input contact 6 to the output contact 7 by arranging the respective contacts as described above and bringing the contact portions of the respective contacts into contact with each other.

  Moreover, also in the second embodiment, the shape of the contact surface of each contact portion 61 of the input contact 6 is formed in an oval shape. Each contact portion 61 is provided such that the minor axis direction of the ellipse of the contact surface is the arrangement direction of the contact points (the linear direction).

  Also in this embodiment, three permanent magnets 5 are disposed between the contact portions 61 of the input contact 6 and outside the two contact portions 61. As shown in FIGS. 5 and 6, the permanent magnet 5 is arranged on the same straight line so that one pole (for example, N pole) is located on the same side. These permanent magnets 5 apply a magnetic field between the contact portion 61 of the input contact 6 and the contact portion 71 of the output contact 7. Due to the magnetic field of the permanent magnet 5, when the contacts are interrupted, the arc 100 generated between the contacts is stretched and distorted by the Lorentz force.

  In this embodiment, a current flows in parallel from the input contact 6 to the output contact 7 through the two contact portions when the contact is energized. And in the state shown in FIG. 6, the permanent magnet 5 is arrange | positioned so that a magnetic force line may go from left to right. Therefore, according to Fleming's left-hand rule, the Lorentz force has a forward force in FIG. 6, and all of the arc 100 generated when the contact is interrupted is distorted in the forward direction.

  Even when the contact pairs can be connected in parallel, the arcs do not interfere with each other when energized, and no arc interference occurs when a reverse current flows.

(Test example)
Next, in order to investigate the characteristics of the contact contact portion used in the relay, a contact contact portion described below was produced. First, two types of Ag alloys having chemical compositions as the surface layer and inner layer shown in Table 1 were respectively melted and cast to prepare ingots. Each of these was roughly processed, and then the ingot of the surface layer and the inner layer was superposed and joined by a hot roll at 850 ° C. in an argon atmosphere to produce a composite material composed of two layers of Ag alloy. After preheating all the obtained composite materials under the same conditions, a thin pure Ag plate is placed on the inside opposite to the surface layer so that the final thickness becomes 1/10 of the total thickness. Hot pressing was performed on the back side of the layer.

  After that, cold rolled into a hoop-like material, punched out, and shaped A with width 7.5mm, length 8mm, thickness 2mm, and shape B with width and length 5mm, thickness 1.5mm A composite contact tip having a shape was produced. Each of the obtained chips was held at 750 ° C. for 210 hours in an oxygen atmosphere of 15 atm to prepare each contact of Samples 1 to 34 shown in Table 1. Table 1 below shows the average hardness of the surface layer and the thickness of the surface layer according to the micro Vickers standard for the contact points of the obtained samples. Although the hardness of the inner layer is not shown in Table 1, the hardness of the inner layer is lower than that of the surface layer except for the sample 27 having the same hardness as a whole and the sample 33 having a higher hardness in the inner layer.

  The average hardness is measured on a cross-section in the direction perpendicular to the surface of the contact point of each sample within the area of each surface layer and inner layer, and 5 points including the vicinity of the upper and lower ends of each layer in the thickness direction. The hardness was measured, and this operation was performed at six locations near the center of the sample. The arithmetic average value of these 30 measured values was defined as the average hardness of each layer. When the thickness of the surface layer was narrow, 30 points were measured in a direction parallel to the contact contact surface. Further, in the vicinity of the center on the same cross section, the thickness of the surface layer was measured at five points in the direction parallel to the chip surface, and the arithmetic average value of the measured values at these five points was used as the thickness of the surface layer.

  In the composition of each sample shown in Table 1, the amounts of the other components Sb, Ni, Bi of Samples 11 to 18 are all 0.2% by mass. In addition, the surface layer and the inner layer of Samples 19 to 32 have the same chemical composition. The other components and amounts of both layers of Samples 19 to 27 are 0.05% by mass for Sb, Co, and Zn, and 0.2% by mass for Ni. The other components and amounts of both layers of sample 29 are 0.1% by mass for Sb, Pb, Ni, Bi, Co, and Zn, and 0.2% by mass for Ca. The other components and amounts of both layers of the sample 29 are 0.1% by mass for Sb, Ni, Ca, Bi, Co, and Zn, and 0.5% by mass for Pb. Furthermore, as for the other components and the amount of both layers of Samples 30 to 32, both Ni and Zn are 0.2% by mass.

  Samples 1 to 10 are a sample group in which the amount of Sn and In is changed to control the hardness of each layer, Samples 11 to 18 are a sample group in which the amount of Sn and In is changed and other components are further added, and Samples 19 to 27 Is a sample group in which the thickness of the surface layer is changed. In Sample 27, since the entire contact has the same hardness, the thickness of the surface layer is expressed as the contact thickness. In Samples 19 to 30, the surface layer and the inner layer have the same chemical composition, and in the manufacturing process of the surface layer and the inner layer other than sample 27, the rolling ratio of the surface layer is increased by 50% of the inner layer. Along with the rolling process, the surface is prepared by annealing the material for a short time at a relatively low temperature of 450 ° C. × 30 minutes in a vacuum, and by performing a shot process after oxidation so as to further increase the hardness. It is a sample group in which the hardness of the layer is controlled. Sample 31 is an example having a hardness of 140 mHv or less, and sample 32 is an example not containing In.

Sample 33 was prepared based on the description in JP-A-61-114417, and Sample 34 was prepared based on the description in JP-A-58-189913. That is, the contact portion of the sample 33 was prepared by melting and casting each Ag alloy of the surface layer and the inner layer having the composition shown in Table 1, hot pressing and rolling, and then punching the material. Oxidized by holding at 780 ° C. for 210 hours in an atmosphere. The contact contact part of Sample 34 is obtained by melting and casting each Ag alloy of the surface layer and the inner layer, forming unevenness with a depth of 0.5 mm at a pitch of 1 mm in the horizontal direction on the mating surfaces of each other, The parts are in mesh with each other, heated to 400 ° C while being pressed at ² ton / cm ² and hot-pressed, then cold-rolled and further oxidized at 650 ° C in an oxygen atmosphere of 1 atm. .

  Next, a fixed-side and movable-side copper base metal having the shape shown in FIG. 10 is prepared, and as shown in FIG. 10 (A), the contact tip 11 is fixed to the fixed side base metal 13, and as shown in FIG. 10 (B). In addition, the contact tip 10 was brazed to the movable base 12 with copper brazing. Then, it fixed to the earth leakage breaker (henceforth a breaker) of rated AC30-50A flame | frame. Three such breaker assemblies were prepared for each sample contact pair. Using all the assemblies of Samples 1 to 34, the insulation characteristics are confirmed by performing an interruption test at 220V load, with a breaking current of 1.5KA for the 30A frame and a breaking current of 5KA for the 50A frame. did. For the insulation characteristics, the resistance value between power loads was measured, and the minimum value is shown in Table 2 below. In addition, we compared the wear state of the original contact and the contact after the interruption test, and evaluated the variation of the contact wear state on a 10-point scale.

  Similarly, the variation characteristic of the contact consumption state was also confirmed for the electromagnetic switch. In other words, a 4000A breaking test was performed with a 400AF rated electromagnetic switch using each contact of Samples 1 to 34, and the switching was performed 100,000 times by closing at 2400A or opening at 400A. In the comparison before and after each test, the degree of variation in the amount of contact consumption was visually confirmed, and the size of the variation in the consumption state was evaluated on a 10-point scale. In addition, at the stage of making each of these samples, the contactability of the contact when joining the contact to the base metal, the low flow state, the presence or absence of abnormalities such as cracks occurring on the contact surface, Depending on the occurrence situation, it was evaluated with a maximum of 10 points. The above evaluation results are shown in Table 2 below.

  From the above results, the following can be understood. (1) The Sn concentration of the surface layer is controlled within the range of 1 to 9% by mass, the JIS-defined micro Vickers standard hardness is 150 mHv or more in terms of the average value of the surface layer, and more preferably the surface layer thickness is 10 μm The breaker and electromagnetic switch using the contact contact portion controlled as described above are in a sufficiently practical range in the comprehensive evaluation. On the other hand, breakers and electromagnetic switches using contacts of comparative examples outside the above range have not reached the practical level in comprehensive evaluation. (2) The same can be said even when a small amount of other components are contained in addition to Sn and In. (3) Since each contact contact portion produced on the basis of the descriptions in JP-A-61-114417 and JP-A-58-189913 has not been subjected to any special treatment for controlling the hardness, the surface hardness level is It was outside the specified range of the invention, and in general, practical level performance was not obtained. Therefore, from these results, it is expected that the contact point contact portion can be suitably used in a DC relay.

  The direct current relay of the present invention can be suitably used in fields where space-saving requirements are severe, such as electric vehicles and hybrid vehicles as well as ordinary vehicles using engines.

The schematic block diagram which shows 1st Embodiment of this invention relay shows the state at the time of the electricity supply which the contact is contacting. The schematic block diagram which shows 1st Embodiment of this invention relay shows the state at the time of the interruption | blocking when a contact is non-contact. It is a figure which shows the specific structure which concerns on 1st Embodiment of this invention relay, Comprising: A longitudinal cross-sectional view is shown. It is a figure which shows the specific structure which concerns on 1st Embodiment of this invention relay, Comprising: A cross-sectional view is shown. The schematic block diagram which shows 2nd Embodiment of this invention relay shows the state at the time of the electricity supply which the contact is contacting. It is a schematic block diagram which shows 2nd Embodiment of this invention relay, and the state at the time of interruption | blocking when a contact is non-contact is shown. It is a schematic sectional drawing which shows a specific example of the contact contact part used for this invention relay. It is a schematic sectional drawing which shows the other specific example of the contact contact part used for this invention relay. It is a schematic sectional drawing which shows the other specific example of the contact contact part used for this invention relay. It is a schematic perspective view which shows the state which attached the contact contact part used for this invention relay to a base metal, (A) shows a movable side and (B) shows a fixed side.

Explanation of symbols

1 Casing
21,6 Input contact
21a, 61 Contact part
22,7 Output contact
22a, 71 Contact part
3 Linked contacts
31 Contact area
4 Contact drive mechanism
41 Spring
42 Solenoid
43 Drive shaft
44 Shaft actuator
5 Permanent magnet
110 Inner layer
120 surface layer
130 connection layer
10, 11 Contact tip
12 Movable base metal
13 Fixed side base metal

Claims (8)

A DC relay comprising a contact pair having contact contact portions that open and close each other,
The contact point contact portion is made of an Ag alloy containing 1 to 9% by mass of Sn and having Cd as an impurity of less than 1% by mass,
A direct current relay characterized in that the average hardness on the surface of the contact point is 150 mHv or more based on the micro Vickers standard defined by JIS. A plurality of the contact pairs are provided, and further have a plurality of magnets,
These multiple magnets are arranged on a single straight line, and a contact pair is arranged between these magnets so that they are on the same line,
2. The direct current relay according to claim 1, wherein the magnet is provided so as to distort an arc generated between the contact points when the relay is interrupted in a direction intersecting the line. 3. The DC relay according to claim 2, wherein the surface of the contact point contact portion is formed such that a length in the linear direction is shorter than a length in a direction orthogonal to the straight line. 4. The DC relay according to claim 2, wherein each of the contact pairs is configured to be connectable in series. 4. The DC relay according to claim 2, wherein each of the contact pairs is configured to be connectable in parallel. The contact contact portion has a two-layer structure of a surface layer having an average surface hardness of 150 mHv or more and an inner layer having a lower hardness than the surface layer, and the thickness of the surface layer is 10 μm or more. The DC relay according to claim 1 or 2. 7. The DC relay according to claim 6, wherein the Sn content in the surface layer is equal to or greater than the Sn content in the inner layer. The additive component other than Sn includes at least one element selected from the group consisting of In, Sb, Ca, Bi, Ni, Co, Zn, Te, Cr, and Pb. DC relay described in 1.

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