Patent Grant
10943753
The present invention relates to an electromagnetic relay, and especially to an electromagnetic relay capable of effectively extinguishing a generated arc.
As a conventional electromagnetic relay, for example, there has been disclosed an electromagnetic relay including: an armature which tilts by excitation and non-excitation of an electromagnetic block; a movable contact portion which has a movable contact, is mounted on the armature, and tilting together with tilting of the armature; and a fixed contact portion having a fixed contact with which the movable contact comes into or out of contact. In the electromagnetic relay, an arc extension space is formed to extend an arc that is generated when the movable contact comes into or out of contact with the fixed contact, and a magnetic field generation unit is provided to guide, to the arc extension space, an arc that is generated when the movable contact comes into or out of contact with the fixed contact (cf. PTL 1).
In the above electromagnetic relay, as shown in
PTL 1 Japanese Unexamined Patent Application Publication No. 2013-80692
However, in the above electromagnetic relay, the permanent magnet is disposed each between adjacent fixed contacts so as to extend the arc upward. Since the electromagnetic relay requires an arc extinguishing space having an equivalent size for each pair of the movable contact 21a and the fixed contact 22a, the apparatus is hard to be reduced in size and has little flexibility in designing, which has been problematic.
In view of the above problem, an object of the present invention is to provide an electromagnetic relay that is easily reduced in size and has great flexibility in designing.
An electromagnetic relay according to the present invention, comprises:
a first movable contact and a second movable contact which are disposed on a movable contact piece;
a first fixed contact and a second fixed contact which are disposed so as to contactably and separably face the first movable contact and the second movable contact; and
a magnetic field generation unit disposed so as to attract in a predetermined direction an arc generated between the first movable contact and the first fixed contact and an arc generated between the second movable contact and the second fixed contact,
wherein, when a predetermined time has passed after generation of an arc at least either between the first movable contact and the first fixed contact or between the second movable contact and the second fixed contact, an arc generated between the first movable contact and the first fixed contact is extended by the magnetic field generation unit to be longer than an arc generated between the second movable contact and the second fixed contact.
According to the present invention, when a predetermined time has passed after generation of the arc at least either between the first movable contact and the first fixed contact or between the second movable contact and the second fixed contact, the arc generated between the first movable contact and the first fixed contact is cut off by being extended by the magnetic field generation unit to be longer than the arc generated between the second movable contact and the second fixed contact. Hence, there is no need to provide an arc extinguishing space having an equivalent size for each pair of the movable contact and the fixed contact.
For example, the arc generated between the first movable contact and the first fixed contact can be cut off by being attracted and extended long by the magnetic field generation unit to the arc extinguishing space that is a dead space inside the electromagnetic relay. Hence, the arc extinguishing space for extinguishing the arc generated between the second movable contact and the second fixed contact does not need to have an equivalent size to that of the dead space. As a result, it is possible to obtain an electromagnetic relay that is not only easily reduced in size but also has great flexibility in designing.
Another electromagnetic relay according to the present invention, may comprise:
a first movable contact and a second movable contact which are disposed on a movable contact piece;
a first fixed contact and a second fixed contact which are disposed so as to contactably and separably face the first movable contact and the second movable contact; and
a magnetic field generation unit disposed so as to attract in a predetermined direction an arc generated between the first movable contact and the first fixed contact and an arc generated between the second movable contact and the second fixed contact,
wherein, a magnetic flux density of the magnetic field generation unit is set such that a magnetic flux density between the first movable contact and the first fixed contact is larger than a magnetic flux density between the second movable contact and the second fixed contact.
According to the present invention, when a predetermined time has passed after generation of the arc between the first movable contact and the first fixed contact, the arc generated between the first movable contact and the first fixed contact is cut off by being extended by the magnetic field generation unit to be longer than the arc generated between the second movable contact and the second fixed contact. Hence, the arc extinguishing space for extinguishing the arc generated between the second movable contact and the second fixed contact may be small. As a result, even when a resin mold is disposed in the vicinities of the second movable contact and the second fixed contact, the arc is hard to come into contact with the mold, and it is reliably possible to prevent generation of dust and an organic gas.
Another electromagnetic relay according to the present invention, may comprise:
a first movable contact and a second movable contact which are disposed on a movable contact piece;
a first fixed contact and a second fixed contact which are disposed so as to contactably and separably face the first movable contact and the second movable contact; and
a magnetic field generation unit disposed so as to attract in a predetermined direction an arc generated between the first movable contact and the first fixed contact and an arc generated between the second movable contact and the second fixed contact,
wherein, a contact-to-contact distance between the first movable contact and the first fixed contact at time of contact separation is made larger than a contact-to-contact distance between the second movable contact and the second fixed contact at time of contact separation.
According to the present invention, the first movable contact and the first fixed contact are separated from each other earlier than the second movable contact and the second fixed contact.
That is, the arc between the first movable contact and the first fixed contact is generated earlier than the arc between the second movable contact and the second fixed contact. For this reason, by adjusting a distance between the contacts at the time of separation thereof, the arc generated between the first movable contact and the first fixed contact is extended long and cut off earlier than the arc generated between the second movable contact and the second fixed contact. As a result, the arc extinguishing space for extinguishing the arc generated between the second movable contact and the second fixed contact may be made small. Accordingly, even when the resin mold is disposed in the vicinities of the second movable contact and the second fixed contact, the arc is hard to come into contact with the mold, and it is reliably possible to prevent generation of dust and an organic gas.
As an embodiment of the present invention, a shape of the movable contact piece may be set such that a distance from the movable contact piece to the first fixed contact is larger than a distance from the movable contact piece to the second fixed contact.
According to the present embodiment, the distance between the contacts is adjusted by the shape of the movable contact piece, to enable adjustment of the arc generation time.
As a different embodiment of the present invention, a height dimension of the first fixed contact may be made smaller than a height dimension of the second fixed contact.
According to the present embodiment, the distance between the contacts is adjusted using fixed contacts with different height dimensions, to enable adjustment of the arc generation time.
As a new embodiment of the present invention, a height dimension of the first movable contact may be made smaller than a height dimension of the second movable contact.
According to the present embodiment, the distance between the contacts is adjusted using movable contacts with different height dimensions, to enable adjustment of the arc generation time.
As another embodiment of the present invention, the arc generated between the first movable contact and the first fixed contact may be attracted and extended to an arc extinguishing space that is disposed in a direction that, as seen from the first movable contact or the first fixed contact, is opposite to the facing first fixed contact or the facing first movable contact.
According to the present embodiment, the arc can be extended to a sufficient length by attracting the arc to the arc extinguishing space, thus exerting the effect of reliably cutting off the arc.
An electromagnetic relay according to the present invention is described in accordance with attached drawings of
An electromagnetic relay according to the first embodiment (
As shown in
According to the present embodiment, there is an advantage that an increase in size of the electromagnetic relay can be avoided by effectively using the dead space of the base 10 as the arc extinguishing space 19.
In the lower surface of the base 10, as shown in
As shown in
As shown in
As shown in
Directions of magnetic poles of the first permanent magnet 30 and the second permanent magnet 32 are set corresponding to a direction of a current that flows between the fixed contacts 21a to 24a and the movable contacts 86a, 86b, 87a, 87b when fixed contact terminals 22, 23 are electrically connected. Hence, the first permanent magnet 30, the auxiliary yoke 31, and the second permanent magnet 32 can attract arcs respectively generated between the fixed contacts 21a, 22a, 23a, 24a and the movable contacts 86a, 86b, 87a, 87b in predetermined directions to extend and extinguish the arcs.
In particular, by adjusting the shape or the position of the auxiliary yoke 31, magnetic force lines of the first permanent magnet 30 can be changed in desired directions. It is thus possible to prevent leakage of a magnetic flux of the first permanent magnet 30 in the first permanent magnet 30 while adjusting the arc attracting direction, thereby to enhance the magnetic efficiency.
That is, as shown in
Further, the first permanent magnet 30 and the auxiliary yoke 31 are disposed so as to generate magnetic force lines that can attract the arc generated between the fixed contact 24a and the movable contact 87b in the direction opposite to the movable contact 87b as seen from the fixed contact 24a.
The second permanent magnet 32 is disposed so as to generate magnetic force lines that can attract the arc generated between the fixed contact 22a and the movable contact 86b so as to move to the upper surface of the base 10.
Further, the second permanent magnet 32 is disposed so as to generate magnetic force lines that can attract the arc generated between the fixed contact 23a and the movable contact 87a in the direction opposite to the upper surface of the base 10.
Note that the electromagnetic relay according to the present embodiment has four poles. However, in the present embodiment, the arc generated between the facing fixed contact 22a and movable contact 86b and the arc generated between the facing fixed contact 23a and movable contact 87a can be attracted by three permanent magnets in predetermined directions. Hence, there is an advantage that the number of components is smaller than in the conventional case.
In the present embodiment, the description has been given of the configuration where, as shown in
The first permanent magnet 30 and the auxiliary yoke 31 are inserted into the notched groove 17 (
According to the present embodiment, the first and second permanent magnets 30, 32 and the auxiliary yoke 31 are assembled from the lower surface of the base 10. Hence, it is possible to prevent deterioration in the first and second permanent magnets 30, 32 and the auxiliary yoke 31 caused by the generated arc. Further, since the thickness dimension of the base 10 is effectively usable, it is possible to obtain a space-saving electromagnetic relay.
Note that all of the first permanent magnet 30, the auxiliary yoke 31, and the second permanent magnet 32 are not necessarily required to be assembled from the lower surface of the base 10, but may be assembled from the upper surface of the base 10 as needed.
Further, the permanent magnet, or the permanent magnet and the auxiliary yoke, may be disposed behind each of the fixed contacts 21a to 24a.
The foregoing auxiliary yoke 31 is not restricted to the rectangular-shaped platy magnetic member, but may, for example, have a substantially L-shape in front view (
Further, the foregoing auxiliary yoke 31 may be a rectangular platy magnetic member with chamfered corners (
In the arc extinguishing space 19, for example, an arc cut-off member 100 as shown in
The arc cut-off member 100 is formed by bending a strip metal plate to have a substantially J-shape in cross section. A plurality of projections 101 being substantially triangular in cross section are provided to project from the front surface of arc cut-off member 100. The projections 101 is for expanding a contacting area with the arc to enhance the rapid cooling efficiency. At both-side edges of the front surface of the arc cut-off member 100, ribs 102 are bent and raised so as to face each other. Further, at both-side edges of the bottom surface of the arc cut-off member 100, ribs 103 are bent and raised so as to face each other. The ribs 102, 103 are for preventing leakage of the generated arc from the arc extinguishing space 19.
As another arc cut-off member 100, for example as shown in
As shown in
In the spool 41, a through hole 45 being rectangular in cross section is provided in a trunk portion 44 having flange portions 42, 43 at both ends, and an insulating rib 46 is provided to laterally project from the outward surface of one flange portion 42. Further, the removal of the spool 41 is prevented by engaging relay clips 50 into engaging holes 47 provided at both-side edges of the other flange portion 43 (
As shown in
As shown in
The yoke 55 is made of a magnetic plate that is bent to have a substantially L-shape in cross section. In the yoke 55, an engaging projection 56a is bent and raised at the center of a horizontal portion 56, and supporting projections 56b are cut and raised at both-side edges of the tip of the horizontal portion 56. Further, the yoke 55 is formed in such a shape that the lower end 57a of the vertical portion 57 can be press-fitted into the press-fitting hole 14 of the base 10.
The movable iron piece 60 is made of a platy magnetic member. As shown in
In the movable iron piece 60, the notched portion 62 is engaged to the supporting projections 56b of the yoke 55. Further, the movable iron piece 60 is rotatably supported by coupling the engaging projection 61 to the engaging projection 56a of the yoke 55 via a restoring spring 63.
The movable contact pieces 80, 81 each have a substantially T-shape in front view, and the movable contacts 86a, 86b, 87a, 87b are fixed at both ends of large width portions 82, 83 of the movable contact pieces 80, 81 via conductive lining members 84, 85. The lining members 84, 85 substantially increase sectional areas of the large width portions 82, 83 to reduce electric resistance and suppress heat generation. Further, as described above, the arc is attracted so as to move obliquely upward in the direction opposite to the movable contact 86a and the movable contact 87b, as seen from the fixed contacts 21a, 24a. Accordingly, the generated arc is hard to come into contact with the movable contact pieces 80, 81 themselves, and it is thus possible to prevent deterioration in the movable contact pieces 80, 81 caused by the arc.
The movable contact pieces 80, 81 are integrally formed by insert-molding of the top ends thereof with a movable stage 74. Then, as shown in
Then, the electromagnetic block 40 mounted with the movable contact pieces 80, 81 is housed into the base 10, and a flange portion 42 of the spool 41 is placed on the stepped portion 13 (
Specifically, at least either the insulating rib 46 or 72 is disposed so as to cut off the shortest-distance straight line connecting between each of the fixed contacts 22a, 23a (or the fixed contact terminals 22, 23) and the magnetic pole portion 53. This leads to an increase in spatial distance from the magnetic pole portion 53 of the iron core 52 to each of the fixed contacts 22a, 23a, and high insulating properties can thus be obtained.
Further, the insulating rib 72 may be disposed so as to cut off the shortest-distance straight line connecting between the tip edge of the insulating rib 46 and the magnetic pole portion 53. This can lead to an increase in spatial distance from the magnetic pole portion 53 of the iron core 52 to each of the fixed contacts 22a, 23a, and higher insulating properties can thus be obtained.
Note that a length dimension of the insulating rib 46 projecting from the outward surface of the flange portion 42 is preferably a length dimension that is smaller than a distance from the outward surface of the flange portion 42 to the tip of each of the fixed contacts 22a, 23a. This is because, if the length dimension of the insulating rib 46 is a length dimension that is larger than the distance from the outward surface of the flange portion to the tip of each of the fixed contacts 22a, 23a, operation of the movable contact pieces 80, 81 might be hindered. As another reason, the arcs respectively generated between the fixed contacts 22a, 23a and the movable contacts 86b, 87a are more likely to hit against the insulating rib 72, causing the insulating rib 72 to easily deteriorate. Accordingly, a more preferable length dimension of the insulating rib 46 is a length dimension from the outward surface of the flange portion 42 to the outward surface of each of the fixed contact terminals 22, 23.
As shown in
Thus, when the cover 90 is fitted to the base 10 with the electromagnetic block 40 assembled therein, the engagement receiving portion 92 of the cover 90 is engaged and fixed to the engaging claw portion 10a of the base 10. The position regulation ribs 93 then come into contact with the horizontal portion 56 of the yoke 55 to regulate lifting of the electromagnetic block 40 (
In the present embodiment, the sealing material is injected to enable the first and second permanent magnets 30, 32 and the auxiliary yoke 31 to be fixed onto the base 10, while simultaneously sealing a gap between the base 10 and the cover 90. Thus, according to the present embodiment, it is possible to obtain an electromagnetic relay taking a small number of operation steps and having high productivity.
Next, the operation of the above embodiment is described.
When the electromagnetic block 40 is not excited, as shown in
When a voltage is applied to the coil 51 for excitation, the movable iron piece 60 is attracted to the magnetic pole portion 53 of the iron core 52, and the movable iron piece 60 rotates clockwise against the spring force of the restoring spring 63. For this reason, the movable contact pieces 80, 81 rotate together with the movable iron piece 60, and the movable contacts 86a, 86b, 87a, 87b respectively come into contact with the fixed contacts 21a, 22a, 23a, 24a. Thereafter, the movable iron piece 60 is attracted to the magnetic pole portion 53 of the iron core 52 (
Subsequently, when the application of the voltage to the coil 51 is stopped, the movable iron piece 60 rotates clockwise by the spring force of the restoring spring 63, and the movable iron piece 60 is separated from the magnetic pole portion 53 of the iron core 52. Thereafter, the movable contacts 86a, 86b, 87a, 87b are respectively separated from the fixed contacts 21a, 22a, 23a, 24a to return to the original state.
According to the present embodiment, as shown in
According to the present embodiment, the arc 110 can be attracted to the oblique backward of the fixed contacts 21a, 24a and extinguished only by the first permanent magnet 30. The oblique backward of the fixed contacts 21a, 24a here means a direction that, as seen from the fixed contacts 21a, 24a, is opposite to the facing movable contacts 86a, 87b, and in the direction opposite to the base.
Further, by disposing the auxiliary yoke 31, the arc 110 can be attracted in a right and left direction, to adjust the attracting direction. The right and left direction of the arc 110 means a direction vertical to a direction in which the fixed contacts 21a, 24a and the movable contacts 86a, 87b face each other, as well as a direction parallel to the upper surface of the base.
Thus, according to the present embodiment, the generated arc 110 does not come into contact with the inner surface of the cover 90 and the electromagnetic block 40, to thereby be extended obliquely backward in an appropriate direction. This enables more effective extinguish of the arc 110.
According to the present embodiment, there is an advantage that an increase in size of the apparatus can be avoided since the dead space located behind each of the fixed contacts 21a, 24a is effectively used as the arc extinguishing space 19.
Needless to say, the shapes, sizes, materials, disposition, and the like of the first and second permanent magnets 30, 32 and the auxiliary yoke 31 are not restricted to those described above, but can be changed as necessary.
A working example 1 is an analysis of directions and strength of the magnetic force lines in the case of combining the first and second permanent magnets 30, 32 with the auxiliary yoke 31.
As an analysis result, the directions of the magnetic force lines are shown by vector lines (
A working example 2 is an analysis of directions and strength of the magnetic force lines in the case of disposing the components in the same manner as in the working example 1 described above except for not providing the auxiliary yoke 31.
As an analysis result, the directions of the magnetic force lines are shown by vector lines (
It could be confirmed from
Further, it could be confirmed, by comparing the results described in
As shown in
The same portions are provided with the same numerals and descriptions thereof are omitted.
In the present embodiment, for example, as shown in
In short, the time taken for the arc 111 to be extended to a predetermined length is shorter than that for the arc 112.
Accordingly, in the same time period, the arc 111 generated between the fixed contact 24a and the movable contact 87b can be extended longer than the arc 112 generated between the fixed contact 23a and the movable contact 87a. When the arc 111 is attracted by the first permanent magnet 30 to the arc extinguishing space 19 and cut off, the arc 112 is simultaneously cut off since the movable contact 87a and the movable contact 87b are electrically connected with each other. Accordingly, the arc 112 can be cut off before being extended long.
When the arc 111 is extended to a sufficient length and can be cut off early, it is possible to reduce insulation deterioration in the spaces between the fixed contacts 24a, 23a and the movable contacts 87b, 87a due to heat generation of the arcs 111, 112. It is thereby possible to prevent regeneration of the arcs 111, 112.
According to the present embodiment, the arc 111 can be extended longer than the arc 112 within the same time period. For this reason, when the generated arc 111 is extended to the sufficient strength and can be cut off before extension of the arc 112, the arc 112 is simultaneously cut off and thus need not be extended long. As a result, a large space is not needed for extinguishing the arc 112. Further, the arc 112 does not come into contact with a resin mold, not causing the problem of insulation deterioration due to generation of dust and an organic gas.
Thus, according to the present embodiment, it is possible to obtain a small-sized electromagnetic relay where the problem of insulation deterioration caused by an arc does not occur even when a large current is allowed to flow.
As shown in
Thus, for example as shown in
That is, before generation of the arc 112 or at the time of generation of the arc 112, the arc 111 is in the state of having already been extended long by the first permanent magnet 30. When the arc 111 is extended to the sufficient length by use of the arc extinguishing space 19 and cut off, the arc 112 is simultaneously cut off since the movable contact 87a and the movable contact 87b are electrically connected with each other. Accordingly, the arc 112 can be cut off before being extended long.
When the arc 111 is extended to the sufficient length and cut off, it is possible to reduce insulation deterioration in the spaces between the fixed contacts 24a, 23a and the movable contacts 87b, 87a due to heat generation of the arcs 111, 112. It is thereby possible to prevent regeneration of the arcs 111, 112.
According to the present embodiment, the distance between contacts can be adjusted only by providing the movable contacts 86a, 86b, 87a, 87b on the movable contact pieces 80, 81 with a stepped portion provided therebetween. This enables simple adjustment of the timing for generation of the arc 111 and the arc 112.
That is, when the distance between contacts is adjusted to an appropriate size, the arc 111 can be extended to the sufficient length by the second permanent magnet 32 before generation of the arc 112. Thus, when the arc 111 is extended to the sufficient length by the first permanent magnet 30 and attracted to the arc extinguishing space 19 and cut off, the arc 112 is simultaneously cut off since the movable contact 87a and the movable contact 87b are electrically connected with each other. Accordingly, the arc 112 can be cut off before being extended long. As a result, a large space is not needed for extinguishing the arc 112. Further, the arc 112 does not come into contact with the resin mold, not causing the problem of insulation deterioration due to generation of dust and an organic gas.
Thus, according to the present embodiment, it is possible to obtain a small-sized electromagnetic relay where the problem of insulation deterioration caused by an arc is prevented from occurring only by forming a simple structure of adjusting a distance between the contacts even when a large current is allowed to flow.
As shown in
Hence, the contact-to-contact distance between the fixed contact 21a and the movable contact 86a is larger than the contact-to-contact distance between the fixed contact 22a and the movable contact 86b. Similarly, the contact-to-contact distance between the fixed contact 24a and the movable contact 87b is larger than the contact-to-contact distance between the fixed contact 23a and the movable contact 87a.
In the present embodiment, as shown in FIG. 24, at the time of rotating and returning the movable contact piece 81 in the operating state, before separation of the movable contact 87a from the fixed contact 23a, namely before generation of the arc 112, the movable contact 87b is separated from the fixed contact 24a and the arc 111 is generated. Thus, before generation of the arc 112 or at the time of generation of the arc 112, the arc 111 is in the state of having already been extended long by the first permanent magnet 30. As a result, when the arc 111 is extended to the sufficient length by use of the arc extinguishing space 19 and cut off, the arc 112 is simultaneously cut off since the movable contact 87a and the movable contact 87b are electrically connected with each other. Accordingly, the arc 112 can be cut off before being extended long.
When the arc 111 is extended to the sufficient length and cut off, it is possible to reduce insulation deterioration in the spaces between the fixed contacts 24a, 23a and the movable contacts 87b, 87a due to heat generation of the arcs 111, 112. It is thereby possible to prevent regeneration of the arcs 111, 112.
According to the present embodiment, it is possible to adjust the distance between the contacts only by reducing the height dimensions of the fixed contacts 21a, 24a. This enables simple adjustment of the timing for generation of the arc 111 and the arc 112.
That is, when the distance between contacts is adjusted to an appropriate value, the arc 111 can be extended to the sufficient length by the second permanent magnet 32 before generation of the arc 112 or at the time of generation of the arc 112. Thus, when the arc 111 is extended to the sufficient length by the first permanent magnet 30 and attracted to the arc extinguishing space 19 and cut off, the arc 112 is simultaneously cut off since the movable contact 87a and the movable contact 87b are electrically connected with each other. Accordingly, the arc 112 can be cut off before being extended long.
Needless to say, the distance between the contacts may be adjusted by making the height dimensions different between the pair of adjacent movable contacts 86a, 86b or the pair of adjacent movable contacts 87a, 87b.
In a fifth embodiment, as shown in
In the present embodiment, as shown in
When the arc 111 is extended to the sufficient length and cut off, it is possible to reduce insulation deterioration in the spaces between the fixed contacts 24a, 23a and the movable contacts 87b, 87a due to heat generation of the arcs 111, 112. It is thereby possible to prevent regeneration of the arcs 111, 112.
According to the present embodiment, only by performing torsion processing on the movable contact pieces 80, 81 which are existing components, it is possible to incline the movable contact pieces 80, 81. There is thus an advantage that installation of a new manufacturing facilities can be reduced to prevent a cost increase.
The generation status of arcs in the case of applying a high load to the electromagnetic relay according to the above embodiment was measured as follows:
In a working example 3, measurement was performed on the electromagnetic relay according to the second embodiment (
A magnetic flux density in the vicinities of the contacts at the time of contacting between the fixed contacts 21a, 24a and the movable contacts 86a, 87b by the first permanent magnet 30 was set to 46 mT. A magnetic flux density in the vicinities of the contacts at the time of contacting between the fixed contacts 22a, 23a and the movable contacts 86b, 87a by the second permanent magnet 32 was set to 24 mT.
The fixed contact terminal 22 and the fixed contact terminal 23 were connected with each other via a resistor, not shown, and the generation status of arcs was measured in the case of applying a voltage of 1000V between the fixed contact terminal 21 and the fixed contact terminal 24. Note that a value of the resistor has been set such that a current of 15A flows in a state where each of the fixed contacts 21a, 22a, 23a, 24a and the movable contacts 86a, 86b, 87a, 87b come into contact. A graph of
In
In the graph of
Further, it could thus be confirmed that the arc continuation time “t1+t2” for each of arcs between the fixed contacts 21a, 22a, 23a, 24a and the movable contacts 86a, 86b, 87a, 87b was short.
Further, according to the graph of
In particular, the numbers of vibrations in contact-to-contact voltages “V2”, “V3” between the fixed contacts 22a, 23a and the movable contacts 86b, 87a, disposed in the vicinity of the resin mold, were small. It was thus found possible to reliably extinguish the arc and reduce generation of dust and an organic gas caused by generation of the arc, and thereby to reliably prevent insulation deterioration.
In a working example 4, measurement was performed on the electromagnetic relay according to the fifth embodiment (
A magnetic flux density in the vicinities of the contacts at the time of contacting between the fixed contacts 21a, 22a, 23a, 24a and the movable contacts 86a, 86b, 87a, 87b by the first and second permanent magnets 30, 32 was set to 24 mT. The fixed contact terminal 22 and the fixed contact terminal 23 were connected with each other via a resistor, not shown, and a voltage of 1000V was applied between the fixed contact terminal 21 and the fixed contact terminal 24, to measure the generation status of arcs. A graph of
According to the graph of
Further, according to the graph of
In particular, the numbers of vibrations in contact-to-contact voltages “V2”, “V3” between the fixed contacts 22a, 23a and the movable contacts 86b, 87a, disposed in the vicinity of the resin mold, were small. It was thus found possible to reliably extinguish the arc and reduce generation of dust and an organic gas caused by generation of the arc, and thereby to reliably prevent insulation deterioration.
In the comparative example 1, the generation status of arcs were measured on similar conditions to those in the working example 3 described above except that the magnetic flux density in the vicinities of the contacts at the time of contacting between the fixed contacts 21a, 22a, 23a, 24a and the movable contacts 86a, 86b, 87a, 87b by the first and second permanent magnets 30, 32 was set to 24 mT. A graph of
According to the graph of
Further, the number of vibrations in voltage waveform showing the generation, extension, and cut-off of the arc during the time “t2” was larger than the number of vibrations in working examples 3, 4. In particular, the numbers of vibrations in contact-to-contact voltages “V2”, “V3” between the fixed contact 22a and the fixed contact 23a, disposed in the vicinity of the resin mold, were greatly larger than the number of vibrations in working examples 3, 4. It was found from this fact that the arc is repeatedly generated, extended, and cut-off a number of times.
The fixed contact terminal 22 and the fixed contact terminal 23 of the electromagnetic relay in the second embodiment (
More specifically, a voltage between the contacts was measured by an oscilloscope to obtain a waveform showing a change in voltage between the contacts. Further, the generated arc was photographed by a high-speed camera, and the photographed image of the arc was subjected to image processing to measure a length of the arc. The arc length is then plotted on a waveform of the voltage between the contacts to obtain a graph (
It could be confirmed from
Describing it in more detail, when a high voltage is applied, the arc 111A is generated between the fixed contact 21a and the movable contact 86a at the moment of separation of the movable contact 86a from the fixed contact 21a. In an initial stage of the separating operation, as the distance between the contacts increases, the arc 111A extends in proportion to this increase, and the arc 111A reaches an arc length almost equivalent to the distance between the contacts (about 3 mm).
Subsequently, the arc 111A is extended by the magnetic force of the first permanent magnet 30, and extended longer than the contact-to-contact distance between the facing fixed contact 21a and movable contact 86a, to become the arc 111B. When insulation resistance in the space where the arc 111B is present becomes larger than insulation resistance in the space located between the facing fixed contact 21a and the movable contact 86a, the new arc 111A is generated between the fixed contact 21a and the movable contact 86a. Simultaneously with this, the extended arc 111B is cut off. The generated new arc 111A is then extended by the magnetic force of the first permanent magnet 30 in the same manner as described above. Thereafter, a phenomenon of generation of the arc 111A and cut-off of the extended arc 111B is repeated in a similar cycle to the above.
Normally, in an electromagnetic relay (
However, in the electromagnetic relay according to the second embodiment, the arc 112 easily comes into contact with the resin mold disposed in the vicinity of the fixed contacts 22a (23a), and dust or an organic gas is thus easily generated. If the dust or the organic gas is generated by the arc 112 coming into contact with the resin mold, insulation deterioration occurs in the internal space to cause a decrease in insulation resistance. Accordingly, for example between the movable contacts 86b (87a) and the fixed contacts 22a (23a), the arc 112 is more easily generated. As a result, even after complete return of the movable contacts 86a, 86b, the arcs 111, 112 are repeatedly generated, extended, and cut off, and the time for completely cutting off the arcs 111, 112 thus becomes long. This causes a vicious cycle of bringing the repeatedly generated arc into contact with the resin mold, generating dust or an organic gas, and shortening the lifetime of the contact.
Accordingly, based on the foregoing knowledge, the present inventors preferentially attracted the arc 111 generated between the movable contacts 86a (87b) and the fixed contacts 21a (24a), in the vicinities of which the resin mold is not disposed, by the magnetic force of the first permanent magnet 30 to extend and early cut off the arc. Accordingly, even when the arc 112 is generated between the movable contacts 86b (87a) and the fixed contacts 22a (23a), in the vicinities of which the resin mold is disposed, the arc 112 can be cut off simultaneously with the arc 111 before extension of the arc 112. Consequently, the present inventors confirmed that the problem caused by generation of the arc 112 can be solved, and completed the present invention.
The present invention is not restricted to the DC electromagnetic relay, but may be applied to an AC electromagnetic relay.
Although the cases of applying the present invention to the electromagnetic relay with the four poles have been described in the above embodiments, this is not restrictive, and it may be applied to an electromagnetic relay with at least one pole.
Needless to say, the present invention is applicable to an electromagnetic relay with two or more poles where two or more movable contacts are provided on one movable contact piece.
Further, the present invention is not restricted to the electromagnetic relay, but may be applied to a switch.
10: base
10
a: engaging claw portion
11: recessed portion
12: partition wall
13: stepped portion
14: press-fitting hole
15
a, 15b, 15c, 15d: terminal hole
16
a, 16b: terminal hole
17: notched groove
18: recessed portion
19: arc extinguishing space
21-24: fixed contact terminal
21
a-24a: fixed contact
25: coil terminal
25
a: connection portion
25
b: terminal portion
30: first permanent magnet
31: auxiliary yoke
32: second permanent magnet
35: magnetic field generation unit
40: electromagnetic block
41: spool
42,43: flange portion
44: trunk portion
45: through hole
46: insulating rib
47: engaging hole
50: relay clip
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 stage
80: movable contact piece
81: movable contact piece
82: large width portion
83: large width portion
84: lining member
85: lining member
86
a,86b: movable contact
87
a,87b: movable contact
90: cover
91: gas releasing hole
92: engagement receiving portion
93: position regulation rib
100: arc cut-off member
101: projection
102: rib
103: rib
104: tongue member
110: arc
111: arc
111A: arc
111B: arc
112: arc
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2014-247345 | Dec 2014 | JP | national |
This application is a continuation of U.S. patent application Ser. No. 15/509,914, filed on Mar. 9, 2017, which is a National Stage Application under 35 USC § 371 of PCT International Application No. PCT/JP2015/071275, which based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2014-247345, filed on Dec. 5, 2014, the entire contents of all of which are incorporated herein by reference.
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| Entry |
|---|
| The Office Action dated Dec. 12, 2018 in a counterpart Chinese Patent application. |
| The Office Action dated Jul. 28, 2020 in a counterpart German patent application. |
| Number | Date | Country | |
|---|---|---|---|
| 20190096616 A1 | Mar 2019 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 15509914 | US | |
| Child | 16204082 | US |
