Electromagnetic relay

Abstract

Electromagnetic relay comprising: a base (10); an electromagnet block (40) with a roller (41) in which a through-bore opening (45) is formed on a flange section (42, 43), the electromagnet block (40) being mounted on an upper surface of the base (10); a movable iron piece (60) configured to be rotatable based on excitation or non-excitation of the electromagnet block (40); a movable contact piece (80, 81) configured to be rotatable together with the movable iron piece (60); a movable contact (86a, 86b, 87a, 87b) attached to a free end of the movable contact piece (80, 81);and a fixed contact (21a, 22a, 23a, 24a) which is attached to a fixed contact terminal (21, 22, 23, 24) and which is arranged such that it is connected to or becomes separable from the movable contact upon rotation of the movable contact piece (80, 81), wherein an insulating rib (46, 72) is formed in such a prominent manner on at least one inwardly facing surface of a spacer (70) which is integrally formed with the movable iron piece (60), and an outwardly facing surface of the flange section (42, 43) such that the insulating rib (46) intersects a straight line which separates a magnetic pole section (53), which is an end section of an iron core (52) projecting from the through-hole (45), and the fixed contact (21a, 22b, 23c, 24d) or the fixed contact terminal (21, 22, 23, 24) connects each other in the shortest way.;

Description

TECHNICAL FIELDThe present invention relates to an electromagnetic relay, and more particularly, to an electromagnetic relay which is provided with an insulating structure and which has high insulating properties.PRIOR ARTConventionally, electromagnetic relays are known having a terminal connection structure of electrical components formed of: as an example thereof, an external terminal provided with an electrical connection part protruding from an upper surface of a socket; and a relay terminal formed by bending an elastic plate-like conductive body into an approximately U-shape, which is press-fitted into a recess portion of an internal abutting part mounted on the socket, which is electrically connected to the internal abutting part, and which clamps the electrical connection part of the external terminal with portions thereof facing each other on both sides.Specifically, the above electromagnetic relay has a terminal connection structure of electrical components characterized by: a fixing tab portion that brings the mutually facing sides on both sides of the relay terminal into pressure contact with inner surfaces of the recess portion of the internal abutting part; and a clamping tab part that is elastically deformed in a plate thickness direction regardless of the fixing tab portion and that clamps the electrical terminal portion of the external terminal (see Patent Literature PTL 1).Moreover, EP 2 639 804 B1 discloses a sealed contact device having a housing, a fixed contact and a movable contact. The fixed contact and the movable contact are disposed opposite to each other in the housing. Moreover, the sealed contact device includes permanent magnets that attract an arc between the fixed contact and the movable contact using a magnetic force, and an arc shielding member that is disposed at a location in the housing to which the arc is attracted by the current flowing between the fixed contact and the movable contact and by the magnetic force between the permanent magnets.Further prior art is formed by DE 699 31 586 T2 and DE 38 23 828 A1.CITATIONSPATENT LITERATUREPTL 1: JP-H06-9102 UPTL 2: EP 2 639 804 B1PTL 3: DE 699 31 586 T2PTL 4: DE 38 23 828 A1SUMMARY OF THE INVENTIONTECHNICAL TASKHowever, as shown in FIG. 5, in the above-described electromagnetic relay, an insulation distance between a magnetic pole portion of a stacked iron core 6 constituting an electromagnet block 10 and a fixed contact is short, causing a disadvantage that the electromagnetic relay has poor insulation properties.The present invention takes these disadvantages into account, and it is an object of the present invention to provide an electromagnetic relay having high insulating properties. This object is achieved by the subject matter according to claim 1. Preferred embodiments are the subject matter of the dependent claims. The invention is defined by the claims, aspects of the invention being set forth below.SOLUTION OF THE OBJECTAccording to one aspect of the invention, an electromagnetic relay as defined by claim 1 comprises, among other things:a socket;an electromagnet block having a roller in which a through hole is formed at a flange portion, the electromagnet block being mounted on an upper surface of the base;a movable iron piece configured to be rotatable based on excitation or non-excitation of the electromagnet block;a movable contact piece configured to be rotatable together with the movable iron piece;a movable contact fixed to a free end of the movable contact piece; anda fixed contact which is fixed to a fixed contact terminal and which is arranged to be connected to or disconnected from the movable contact upon rotation of the movable contact piece, whereinan insulating rib is excellently formed on at least one of an inner facing surface of a spacer integrally formed with the movable iron piece and an outer facing surface of the flange portion such that the insulating rib intersects a straight line connecting a magnetic pole portion, which is an end portion of an iron core protruding from the through hole, and the fixed contact or the fixed contact terminal together in the shortest way.ADVANTAGEOUS EFFECTS OF THE INVENTIONAccording to the present invention, at least one insulating rib is disposed between the magnetic pole portion of the iron core and the fixed contact, so that an insulating distance becomes large, whereby an electromagnetic relay having preferable insulating properties can be obtained.As an embodiment of the present invention, an insulating rib mounted on the inward-facing surface of the spacer in a sideways protruding manner may be disposed in a direction toward the magnetic pole portion of the fixed contact.According to the embodiment, the insulating rib mounted on the inner-facing surface of the spacer in a sideways protruding manner is disposed between the magnetic core portion of the iron core and the fixed contact, so that an insulating distance becomes large, whereby an electromagnetic relay having preferable insulating properties can be obtained.As another embodiment of the invention, an insulating rib mounted on the outward facing surface of the flange portion in a sideways protruding manner may be disposed in a direction toward the magnetic pole portion from the fixed contact.According to the embodiment, the insulating rib mounted on the outward facing surface of the flange portion is disposed between the magnetic core portion of the iron core and the fixed contact in a laterally excellent manner, so that an insulating distance becomes large, whereby an electromagnetic relay having preferable insulating properties can be obtained.As another embodiment of the present invention, the insulating rib mounted on the outward facing surface of the flange portion in a sideways protruding manner may be disposed such that the insulating rib intersects a straight line connecting a distal end of the insulating rib mounted on the inward facing surface of the spacer in a sideways protruding manner and the magnetic pole portion to each other in the shortest way.The embodiment achieves an advantageous effect by forming a longer meandering space so that an insulation property becomes long, and an electromagnetic relay having other advantageous insulation properties can be obtained.BRIEF DESCRIPTION OF THE FIGURESFIG. 1A is a perspective view of an electromagnetic relay according to the present invention as viewed from obliquely above, and FIG. 1B is a perspective view of the electromagnetic relay as viewed from obliquely below. FIG. 2A is a perspective view of the electromagnetic relay according to the present invention as viewed from obliquely above when a cover is removed from the electromagnetic relay, and FIG. 2B is a perspective view of the electromagnetic relay as viewed from obliquely below when the cover is removed from the electromagnetic relay. FIG. 3 is an exploded view of the electromagnetic relay shown in FIG. 1A as viewed obliquely from above. FIG. 4 is an exploded view of the electromagnetic relay shown in FIG. 1A as viewed obliquely from below. FIGS. 5A and 5B show transverse cross-sectional views of the electromagnetic relay corresponding to different positions. FIGS. 6A and 6B show horizontal cross-sectional views of the electromagnetic relay corresponding to different positions. FIGS. 7A and 7B show longitudinal cross-sectional views of the electromagnetic relay corresponding to different positions. FIGS. 8A and 8B show longitudinal cross-sectional views of the electromagnetic relay and a partially enlarged cross-sectional view. FIGS. 9A and 9B show longitudinal cross-sectional views of the electromagnetic relay corresponding to different positions after an operation is ended. FIGS. 10A and 10B show a top view of the base and a bottom view of the base. FIGS. 11A and 11B are a perspective view and a right side view of a modification of an auxiliary yoke, and FIGS. 11C and 11D are a perspective view and a right side view of another modification of the auxiliary yoke. FIGS. 12A and 12B are a perspective view and a longitudinal cross-sectional view of an arc separating member, and FIGS. 12C and 12D are a perspective view and a longitudinal cross-sectional view of another arc separating member. FIGS. 13A and 13B show a schematic plan view and a schematic front view of a contact mechanism. FIGS. 14A and 14B are a plan view and a front view of magnetic force lines of the permanent magnet of the electromagnetic relay according to Embodiment 1 as vector lines. FIGS. 15A and 15B show a plan view and a front view of a magnetic flux density of the permanent magnet of the electromagnetic relay according to Embodiment 1 as a density. FIGS. 16A and 16B show a plan view and a front view of field lines of an electromagnetic relay according to an embodiment 2 as vector lines. FIGS. 17A and 17B show a plan view and a front view of a magnetic flux density of the permanent magnet of the electromagnetic relay according to Embodiment 2 as a density.DESCRIPTION OF THE EMBODIMENTSAn electromagnetic relay according to an embodiment of the present invention will be described with reference to the accompanying drawings and is shown in Figs. 1A to 13D.As shown in FIGS. 3 and 4, the electromagnetic relay according to this embodiment basically includes: a base 10; fixed contact terminals 21 to 24; an electromagnet block 40; a movable iron piece 60; movable contact pieces 80, 81; and a cover 90.As shown in Fig. 10A, on base 10, a pair of partition walls 12, 12 having L-shaped cross sections are formed in a projecting manner on left and right sides of a recessed portion 11 formed at the center of an upper surface of base 10. On the base 10, edge portions which are opposed to each other in the longitudinal direction are disposed with the recessed portion 11 interposed therebetween. A step portion 13 is formed on one edge portion, and an interference-fit bore 14 is formed in the other edge portion. Step portion 13 is provided for supporting a roller 41 of an electromagnet block 40 described below. press-fit bore 14 is provided for allowing press-fit of a lower end portion of lower end portion 57 aof yoke 55 of electromagnet block 40. Of the edge portions opposing each other on the upper surface of the base 10, terminal holes 15a to 15d are arranged on the same straight line along one edge portion, and terminal holes 16, 16 are formed along the other edge portion. Arc extinguishing regions 19, 19 are formed on the base 10 between the partitions 12, 12 and the terminal bores 15a, 15d. A pair of engaging claw portions 10a are formed on outer side surfaces of the socket 10 and face each other with the partition walls 12, 12 interposed therebetween.This embodiment has an advantageous effect that enlargement of the electromagnetic relay can be avoided by utilizing dead portions of the base 10 efficiently as the arc extinguishing portions 19.ViennaFIC. As shown in FIG. 10B, on a lower surface of socket 10, behind the terminal holes 15 a, 15 din which the fixed contact terminals 21, 24 are inserted (toward a side opposite to a mounting direction of movable contacts 86 a, 87 bdescribed later when viewed from the above terminal holes 15 a, 15 d), approximately L-shaped notch grooves 17, 17 that are recess portions are respectively disposed. A portion of notch groove 17 communicates with the outside of a side surface of base 10 such that a later-described first permanent magnet 30 and an later-described auxiliary yoke 31 can be accommodated in notch groove 17. The base 10 has a recessed portion 18 in which a second permanent magnet 32 described below is accommodated between the above-mentioned terminal holes 15 b, 15 c. A pair of ribs 10b, 10b are formed on a lower surface of the base 10 in a projecting manner to eliminate a tilt when the electromagnetic relay of the present invention is mounted on the surface of a substrate.As shown in FIGS. 3 and 4, fixed contacts 21 ato 24 aare fixed to upper end portions of the fixed contact terminals 21 to 24, and terminal portions 21 bto 24 bare formed on lower end portions of the fixed contact terminals 21 to 24. By inserting the terminal portions 21b to 24b into the terminal holes 15a to 15d of the socket 10, the fixed contacts 21a to 24a are aligned on the same straight line. The reason for arranging four fixed contacts 21 ato 24 aas described above is that load voltages individually applied to the fixed contacts 21 ato 24 aare lowered when a DC power source circuit is turned on or off, so that generation of an arc can be suppressed.Coil terminal 25 has a connection bent portion 25 adisposed on an upper end portion thereof, and further has a terminal portion 25 bdisposed on a lower end portion thereof. By press-fitting the terminal portions 25b into the terminal holes 16 formed in the socket 10, coil terminals 25, 25 are aligned along the same straight line.The direction of an electric current flowing between the fixed contacts 21 ato 24 aand the movable contacts 86 a, 86 b, 87 a, 87 band the direction of a magnetic pole of the first permanent magnet 30 and a magnetic pole of the second magnet 32 are fixed. Thus, the first permanent magnet 30, the auxiliary yoke 31, and the second permanent magnet 32 induce, propagate, and quench arc generated between the fixed contacts 21 a, 22 a, 23 a, 24 aand the movable contacts 86 a, 86 b, 87 a, 87 b, respectively, in a predetermined direction. Specifically, auxiliary yoke 31 is provided for changing magnetic field lines of first magnet 30 in a desired direction such that an arc inducing direction is adjusted to eliminate loss of magnetic flux of first permanent magnet 30 and to increase magnetic efficiency.That is, as shown in FIG. 6, an arc generated between the fixed contact 21 aand the movable contact 86 ais induced toward a side opposite to a side opposite to the movable contact 86 bwhen viewed from the fixed contact 21 atoward.An arc generated between the fixed contact 24 aand the movable contact 87 bis induced in the direction that is toward a side opposite to the movable contact 87 bas viewed from the direction of the fixed contact 24 a.An electric current is induced between the fixed contact 22a and the movable contact 86b toward the upper surface of the base 10.An arc generated between the fixed contact 23 aand the movable contact 87 ais induced in a direction toward a side opposite to the upper surface of the base 10.Although the electromagnetic relay according to this embodiment has four poles, an arc generated between the fixed contact 22 aand the movable contact 86 bfacing each other and an arc generated between the fixed contact 23 aand the movable contact 87 afacing each other may be induced in predetermined directions by three permanent magnets. Thus, the electromagnetic relay according to this embodiment has an advantage that the number of parts can be reduced as compared with the related art.By respectively inserting the first permanent magnet 30 and the auxiliary yoke 31 into the notch grooves 17 formed on the base 10, the auxiliary yoke 31 is positioned so as to be adjacent to the first permanent magnet 30. The second permanent magnet 32 is accommodated in the recess portion 18 formed on the base.According to this embodiment, the first and second permanent magnets 30, 32 and the auxiliary yokes 31 are mounted from the lower surface of the base 10, so that it becomes possible to avoid deterioration of the first and second permanent magnets 30, 32 and the auxiliary yoke 31 caused by arc generation. Further, a thickness of the base 10 can be used effectively, and thus it is possible to provide a space saving electromagnetic relay.It is not always necessary to mount all of the first permanent magnet 30, the auxiliary yoke 31, and the second permanent magnet 32 from the lower surface of the base 10. These parts may be mounted from the top surface of base 10 if necessary.The permanent magnets or the permanent magnet and the auxiliary yoke may be disposed behind the fixed contacts 21a to 24a.The above auxiliary yoke 31 is not limited to a rectangular plate-like magnetic member. For example, auxiliary yoke 31 may take an approximately L-shape in a front view (FIG. 12A ). According to such a modification, an inducing direction of an arc can be changed to a desired direction by changing the direction of lines of magnetic force of the first permanent magnet 30 to another direction.The above auxiliary yoke 31 may be formed of a rectangular plate-like magnetic member with corner portions chamfered (FIG. 12B ). According to such a modification, the corner portions are chamfered, and thus auxiliary yoke 31 can be inserted into auxiliary groove 17 in a single manner, thereby providing an advantage of improving assembly performance.In the arc extinguishing portion 19, for example, an arc separating member 100 shown in FIGS. 12A and 12B may be disposed to effectively extinguish a generated arc by rapid cooling.Arc separator 100 is formed by bending a strip-shaped metal plate into an approximately J-shape in cross-sectional view. On a front side of arc separation member 100, a plurality of protrusions 101 having an approximate circular shape are formed in a protruding manner. Protrusions 101 are formed to enhance a rapid cooling effect by enlarging a contact area with an arc. Ribs 102 are bent and raised from both side edge portions on the front side of arc separating member 100 such that ribs 102 face each other, and ribs 103 are also bent and raised from both side edge portions on a lower surface of arc separating member 100 such that ribs 103 face each other. Ribs 102, 103 are provided to prevent a generated arc from coming out of the arc extinguishing portion 19.As another arc separating member 100, for example, as shown in FIGS. 12C and 12D, a plurality of tongue members 104 may be formed by cutting and raising on a front surface of arc separating member 100. Other arrangements of the other arc separating member 100 are the same as the corresponding arrangements of the above-mentioned arc separating member 100, so that like reference numerals are assigned to identical parts, and description of the other arrangements is omitted.As shown in FIGS. 3 and 4, the electromagnet block 40 is constituted by the roller 41, the coil 51, the iron core 52, and the yoke 55.Roller 41 is constructed such that a through hole 45 having a rectangular cross section is formed in a body portion 44 having flange portions 42, 43 at both ends thereof, and an insulating rib 46 is formed on an outward facing surface of a flange portion 42 such that insulating rib 46 protrudes sideways. Engaging holes 47 are formed in both side edge portions of the other flange portion 43 of roller 41, and relay terminals 50 respectively engage with the engaging holes 47, thus preventing removal of roller 41 (FIG. 7B ).Coil 51 is wound around trunk portion 44, solder lines of coil 51 are bonded to bonding portions 50 a(FIG. 6A ) extending from relay terminals 50 and soldered to bonding portions 50 a.Iron core 52 is formed by stacking a plurality of plate-like magnetic members having an approximately planar T-shape. Iron core 52 is provided to fit through through hole 45 formed in roller 41, one end portion of iron core 52 protruding from through hole 45 forms magnetic pole portion 53, and the other end portion 54 of iron core 52 protruding from through hole 45 is press-fixed to vertical portion 57 of yoke 55 having an L-shaped cross section described later.Yoke 55 is formed of a magnetic plate bent in a cross section approximately in an L shape. An engaging protrusion 56 ais formed by bending and raising at the center of a horizontal portion horizontal portion 56, and supporting protrusions 56 bare formed by cutting at both side edge portions of a distal end of horizontal portion 56. Yoke 55 is formed in a shape that allows a lower end portion 57 aof vertical portion 57 to be press-fitted into press-fitting bore 14 formed in base 10.As shown in FIGS. 3 and 4, the movable iron piece 60 is constituted by a plate-like magnetic member. An engaging protrusion 61 is formed on an upper side edge portion of the movable iron piece 60 in an excellent manner, and notch portions 62, 62 are formed on both side edge portions of the movable iron piece 60.By providing engagement of the notch portions 62 with the support projections 56 bof yoke 55, and by connecting engagement projection 61 with engagement projection 56 aof yoke 55 with a return spring 63, the movable iron piece 60 is rotatably supported by yoke 55.The movable contact pieces 80, 81 have an approximately T-shape in a front view. The movable contacts 86a, 86b, 87a, 87b are fixed to both ends of large width portions 82, 83 of the movable contact pieces 80, 81 by conductive fitting members 84, 85. By significantly increasing cross-sectional areas of the large width portions 82, 83, fitting members 84, 85 can reduce the electric resistance and thus suppress generation of heat.Upper end portions of the movable contact pieces 80, 81 are integrally formed with a movable base 74 by insert molding. As shown in FIG. 7B, the movable base 74 is integrally formed with a spacer 70 and the movable iron piece 60 by a rivet 64. An insulating rib 72 is formed on a lower side edge portion of the inner-facing surface of spacer 70, and an insulating rib 73 (FIG. 3 ) partitioning the movable contact pieces 80, 81 is formed on a lower side edge portion of an outer-facing surface of spacer 70 such that insulating rib 73 protrudes to the side.Electromagnet block 40 on which movable contact pieces 80, 81 are mounted is housed in base 10, and flange portion 42 of roller 41 is disposed on step portion 13 of base 10. The lower end portion 57 aof yoke 55 is press-fitted into press-fitting bore 14 formed in base 10 so as to position yoke 55. Accordingly, the relay terminals 50 of the electromagnet block 40 clamp the connection portion 25 aof the coil terminal 25 (FIG. 7A ). The movable contacts 86a, 86b, 87a, 87b face the fixed contacts 21a to 24a in a contactable and separable manner. As shown in FIG. 8, insulating rib 72 of spacer 70 is disposed in the vicinity of an area above insulating rib 46 of roller 41. However, insulating rib 72 may be disposed in the vicinity of a surface under insulating rib 46.Specifically, at least one of the insulating ribs 46, 72 is disposed such that the insulating ribs 46, 72 intersect a straight line connecting the fixed contact 22 a, 23 aor the fixed contact terminal 22, 23 to the magnetic pole portion 53 with the shortest distance. Accordingly, a distance between the magnetic pole portion 53 of the iron core 52 and the fixed contact 22 a, 23 abecomes so large that high insulation properties can be obtained.Further, insulating rib 46 may be disposed such that insulating rib 46 intersects a straight line connecting fixed contact 22 a, 23 aor fixed contact terminal 22, 23 to magnetic pole portion 53 with a shortest distance, and insulating rib 72 may be disposed such that insulating rib 72 intersects a straight line connecting a distal edge portion of insulating rib 46 and magnetic pole portion 53 with a shortest distance. With such an arrangement, a spatial distance of magnetic pole portion 53 of iron core 52 from fixed contact 22 a, 23 acan be increased, so that higher insulation properties can be achieved.Preferably, a length of insulation rib 46 protruding from the outward facing surface of flange portion 42 is shorter than a distance from the outward facing surface of flange portion 42 to the distal end of fixed contact 22 a, 23 a. This is because when a length of insulating rib 46 is greater than a distance from the outward facing surface of flange portion 42 to the distal end of fixed contact 22 a, 23 a, there is a possibility that operation of movable contact piece 80, 81 is blocked.Another reason is that arcs generated between the fixed contacts 22 a, 23 aand the movable contacts 86 b, 87 a, respectively, tend to collide with the insulating rib 46, so that the insulating rib 46 is liable to deteriorate. Thus, the preferred length of insulating rib 46 is the length from the outward facing surface of flange portion 42 to the outward facing surface of fixed contact terminal 22, 23.As shown in FIGS. 3 and 4, cover 90 has a box shape so that cover 90 can be fitted on base 10 on which the above-mentioned electromagnet block 40 is mounted. A pair of gas discharge holes 91, 91 are formed in a ceiling surface of cover 90. Engagement receiving portions 92 engaged with the engagement claw portions 10 aof socket 10 are formed on inner surfaces of cover 90 facing each other, and position limiting ribs 93 are formed on an inner surface of the ceiling of cover 90 in a projecting manner.With such an arrangement, when the cover 90 is fitted on the socket 10, the engagement receiving portions 92 of the cover 90 engage with the engagement claw portions 10 aof the socket 10 is mounted on the electromagnet block 40, so that the cover 90 is fixed to the socket 10. Then, the position limiting ribs 93 are brought into contact with the horizontal portion 56 of the yoke 55 so that raising of the electromagnet block 40 can be limited. In a next step, an assembly process is completed by hermetically sealing base 10 and electromagnet block 40 by injecting and curing a sealing material (not shown in the figure) on a lower surface of base 10.According to this embodiment, simultaneously with sealing a gap between the base 10 and the cover 90 by injecting the sealing material, the first and second permanent magnets 30, 32 and the auxiliary yokes 31 can be fixed to the base 10, so that the number of man-hours for operation can be reduced, thereby obtaining an electromagnetic relay with high productivity.Next, the operation of the above-described electromagnetic relay according to this embodiment will be described.When the electromagnet block 40 is not energized, as shown in FIGS. 7 and 8, the movable iron piece 60 is biased counterclockwise by a spring force of the return spring 63.Then, when coil 51 is excited by applying a voltage to coil 51, movable iron piece 60 is attracted to magnetic pole portion 53 of iron core 52, so that movable iron piece 60 is rotated against a spring force of return spring 63. Accordingly, the movable contact pieces 80, 81 are rotated together with the movable iron piece 60, the movable contacts 86 a, 86 b, 87 a, 87 bare brought into contact with the fixed contacts 21 ato 24 a, and thereafter the movable iron piece 60 is drawn toward the magnetic pole portion 53 of the iron core 52 (FIG. 9 ).In the next step, when the application of a voltage to coil 51 is stopped, movable iron piece 60 is rotated clockwise due to a spring force of return spring 63, movable iron piece 60 is separated from magnetic pole portion 53 of iron core 52, and thereafter movable contacts 86 a, 86 b, 87 a, 87 bare separated from fixed contacts 21 ato 24 aand returned to an initial state.According to this embodiment, as shown in FIGS. 6 and 7, even when an arc 110 is generated when the movable contact 86 a, 87 bis separated from the fixed contacts 21 a, 24 a, magnetic field lines of the first permanent magnet 30 act on the arc through auxiliary yoke 31. Thus, the generated arc 110 is induced in accordance with the Fleming's left-hand rule in arc extinguishing region 19 of base 10 by a Lorentz force, and is stretched and extinguished.According to this embodiment, only by using the first permanent magnet 30, the generated arc 110 can be induced and extinguished in a region behind the fixed contact 21 a, 24 a. However, by disposing auxiliary yoke 31, arc 110 can be induced in an area just behind fixed contact 21 a, 24 a. Accordingly, the arc generated is extended into the area just behind the fixed contact 21a, 24a without being brought into contact with the inner surface of the cover 90, so that the arc 110 can be extinguished more efficiently.Further, according to this embodiment, a dead area behind the fixed contacts 21a, 24a is effectively used as the arc extinguishing area 19, so that the electromagnetic relay according to this embodiment has an advantage that enlargement of the apparatus can be avoided.It goes without saying that the shapes, sizes, materials, arrangements, and the like of the first and second permanent magnets 30, 32 and the auxiliary yoke 31 are not limited to the above-described values, and may be changed as necessary.EMBODIMENT 1In Embodiment 1, an analysis of the directions and amounts of magnetic force lines is performed when the first and second permanent magnets 30, 32 and auxiliary yoke 31 are combined with each other.As a result of the analysis, the directions of the magnetic force field lines are described by vector lines (FIGS. 14A and 14B ) and the amounts of the magnetic force field lines are described in terms of density (FIGS. 15A and 15B ).EMBODIMENT 2In Embodiment 2, when the first and second permanent magnets 30, 32 are arranged in the same manner as in the above-mentioned Embodiment 1, analysis of the directions and amounts of magnetic force lines is performed, except that Embodiment 2 is not provided with the auxiliary yoke 31.As a result of the analysis, the directions of the magnetic force field lines are described by vector lines (FIGS. 16A and 16B ) and the amounts of the magnetic force field lines are described in terms of density (FIGS. 17A and 17B ).By comparing the result of the analysis described in FIGS. 14A and 14B and FIGS. 15A and 15B with the result of the analysis described in FIGS. 16A and 16B and FIGS. 17A and 17B, it is confirmed that by providing auxiliary yokes 31, the directions of the field lines of a magnetic force of the permanent magnet and the distribution of intensities of the field lines of the magnetic force change.It is also confirmed how and to what extent the magnetic force lines of the first and second permanent magnets 30, 32 are applied between the fixed contacts 21a to 24a and the movable contacts 86a, 86b, 87a, 87b, from the results of the analysis shown in Figs. 14A and 14B and Figs. 15A and 15B.INDUSTRIAL APPLICABILITYThe present invention is not limited to a DC electromagnetic relay, and can be applied to a Dc electromagnetic relay.In the present embodiment, a case where the present invention is applied to a four-pole electromagnetic relay has been described. However, the present invention is not limited to such a case, and may also be applied to electromagnetic relays having at least one pole.The present invention is not limited to an electromagnetic relay, and can be applied to a switch.LIST OF REFERENCE CHARACTERS10 Base 10 aengagement claw portion 11 Recessed portion 12 Partition wall 13 Step portion 14 Press-fit hole 15 a, 15 b, 15 c, 15 dConnect hole 16 a, 16 bConnect hole 17 Notch groove 18 Recessed portion 19 Arc extinguishing region 21 to 24 Fixed contact terminal 21 ato 24 aFixed contact 25 Coil terminal 25 aConnection portion 25 bConnection portion 30 First permanent magnet 31 Auxiliary yoke 32 Second permanent magnet 40 Electromagnet block 41 Roller 42, 43 Flange portion 44 Trunk portion 45 Through hole 46 Insulating rib 47 Engaging hole 50 Relay terminal 51 Coil 52 Iron core 53 Magnetic pole portion 55 Yoke 60 Movable iron piece 70 Spacer 71 Recessed portion 72 Insulating rib 73 Insulating rib 74 Movable base 80 Movable contact piece 81 Movable contact piece 82 Large width portion 83 Large width portion 84 Fitting member 85 Fitting member 86 a, 86b movable contact 87a, 87b movable contact 90 cover 91 gas outlet bore 92 engagement receiving portion 93 position limiting rib 100 arc separating member 101 protrusion 102 rib 103 rib 104 tongue member 110 arc

Claims

An electromagnetic relay comprising: a base (10); an electromagnet block (40) having a roller (41) in which a through hole (45) is formed at a flange portion (42, 43), the electromagnet block (40) being mounted on an upper surface of the base (10); a movable iron piece (60) configured to be rotatable based on excitation or non-excitation of the electromagnet block (40); a movable contact piece (80, 81) configured to be rotatable together with the movable iron piece (60); a movable contact (86a, 86b, 87a, 87b) fixed to a free end of the movable contact piece (80, 81); and a fixed contact (21a, 22a, 23a, 24a) fixed to a fixed contact terminal (21, 22, 23, 24), and which is arranged to be connected to or disconnected from the movable contact upon the rotation of the movable contact piece (80, 81), wherein an insulating rib (46, 72) is formed excellent on at least an inner facing surface of a spacer (70) integrally formed with the movable iron piece (60) and an outer facing surface of the flange portion (42, 43) such that the insulating rib (46) intersects a straight line connecting a magnetic pole portion (53), which is an end portion of an iron core (52) protruding from the through hole (45), and the fixed contact (21a, 22b, 23c, 24d) or the fixed contact terminal (21, 22, 23, 24) to each other in the shortest path.The electromagnetic relay according to claim 1, characterized in that an insulating rib (72) mounted on the inner facing surface of the spacer (70) in a sideways protruding manner is disposed in a direction toward the magnetic pole portion (53) of the fixed contact (21a, 22b, 23c, 24d).The electromagnetic relay according to claim 1 or 2, characterized in that an insulating rib (46) mounted on the outward facing surface of the flange portion (42) in a sideways protruding manner is disposed in a direction toward the magnetic pole portion (53) of the fixed contact (21a, 22b, 23c, 24d).The electromagnetic relay according to any one of claims 1 to 3, characterized in that the insulating rib (46) mounted on the outward facing surface of the flange portion (42) in a sideways protruding manner is disposed such that the insulating rib (46) intersects a straight line connecting a distal end of the insulating rib (72) mounted on the inward facing surface of the spacer (70) in a sideways protruding manner and the magnetic pole portion (53) to each other in the shortest way.

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