The present invention relates to an electromagnetic relay, and more particularly to an assembled structure of a permanent magnet which induces an arc.
Conventionally, with respect to an electromagnetic relay, and more particularly, with respect to an electromagnetic relay which extinguishes a generated arc by inducing the arc by making use of a magnetic force of a permanent magnet, there has been known an electromagnetic relay which includes: an armature which tilts in response to excitation or non-excitation of an electromagnetic block; a movable contact portion which has a movable contact, is mounted on the armature and tilts along with tilting of the armature; and a fixed contact portion having a fixed contact with which the movable contact is separably contacted. The electromagnetic relay has an arc extending space therein where an arc generated when the movable contact and the fixed contact are brought into contact with each other or are separated from each other is extended, and the electromagnetic relay includes a magnetic field generating unit which introduces the arc generated when the movable contact and the fixed contact are brought into contact with each other or are separated from each other in the arc extending space (see patent literature 1).
PTL 1: JP-A-2013-80692
However, as shown in FIG. 5 of JP-A-2013-80692, in the above-mentioned electromagnetic relay, a plurality of permanent magnets 50 are mounted in an erected manner on an upper surface of a base 30. Accordingly, the permanent magnets 50 are liable to be deteriorated due to a generated arc. Further, in the electromagnetic relay, the permanent magnets 50 are mounted on the upper surface of the base 30 and hence, a thickness of the base cannot be effectively utilized thus giving rise to a drawback that an electromagnetic relay having a low height cannot be obtained.
The present invention has been made in view of the above-mentioned drawbacks, and it is an object of the present invention to provide an electromagnetic relay having a low height which can minimize the deterioration of permanent magnets.
An electromagnetic relay according to the present invention, includes:
a base;
an electromagnet block mounted on an upper surface of the base;
a movable iron piece configured to be rotatable based on excitation and non-excitation of the electromagnet block;
a movable contact piece configured to be rotatable integrally with the movable iron piece;
a movable contact fixed to a free end portion of the movable contact piece; and
a fixed contact fixed to a fixed contact terminal, and disposed so as to be brought into contact with or separated from the movable contact along with rotation of the movable contact piece, wherein
a permanent magnet configured to induce an arc generated between the movable contact and the fixed contact in a predetermined direction is housed in a recessed portion formed on a lower surface of the base in a direction toward a side opposite to the movable contact as viewed from the fixed contact terminal.
According to the present invention, the permanent magnet is housed in the recessed portion formed on the lower surface of the base and hence, there is no possibility that the permanent magnet is deteriorated by the generated arc and hence, it is possible to provide an electromagnetic relay having a long life.
The permanent magnet is housed from the lower surface of the base and hence, it is possible to provide an electromagnetic relay having a low height by effectively making use of a thickness of the base.
As an embodiment of the present invention, the recessed portion may be a notched groove having an approximately L shape and capable of housing the permanent magnet and an auxiliary yoke disposed adjacently to the permanent magnet therein.
According to the embodiment, it is possible to provide an electromagnetic relay which enables assembling of the auxiliary yoke on the permanent magnet with high positional accuracy and has a favorable operational characteristic.
Lines of magnetic force of the permanent magnet can be changed to a desired direction by way of the auxiliary yoke and hence, the arc can be induced in a desired direction.
It is possible to provide an electromagnetic relay having a favorable magnetic efficiency where a leakage of a magnetic flux can be reduced by providing the auxiliary yoke.
As another embodiment of the present invention, a part of the notched groove is configured to communicate with an outside thereof from a side surface of the base.
The embodiment can acquire advantageous effects that the notched grooves can be easily formed on the base, and undesired walls are eliminated so that it is possible to provide an electromagnetic relay having a small floor area.
An electromagnetic relay according to an embodiment of the present invention is described with reference to attached drawings shown in
As shown in
On the base 10, as shown in
This embodiment has an advantageous effect that large-sizing of the electromagnetic relay can be avoided by effectively making use of dead spaces of the base 10 as the arc extinguishing spaces 19.
As shown in
As shown in
The coil terminal 25 has a bent connecting portion 25a on an upper end portion thereof, and has a terminal portion 25b on a lower end portion thereof. By press-fitting the terminal portions 25b into the terminal holes 16 formed in the base 10, the coil terminals 25, 25 are aligned on the same straight line.
The direction of an electric current which flows between the fixed contacts 21a to 24a and the movable contacts 86a, 86b, 87a, 87b and the directions of a magnetic pole of the first permanent magnet 30 and a magnetic pole of the second magnet 32 are determined. Accordingly, the first permanent magnet 30, the auxiliary yoke 31, and the second permanent magnet 32 induce, extend, and extinguish arcs which are generated between the fixed contacts 21a, 22a, 23a, 24a and the movable contacts 86a, 86b, 87a, 87b in a predetermined direction respectively. Particularly, the auxiliary yoke 31 is provided for changing lines of a magnetic force of the first magnet 30 to a desired direction so as to adjust an arc inducing direction, for eliminating leakage of a magnetic flux of the first permanent magnet 30, and for increasing magnetic efficiency.
That is, as shown in
An arc generated between the fixed contact 24a and the movable contact 87b is induced in the direction toward a side opposite to the movable contact 87b as viewed from the fixed contact 24a.
An arc generated between the fixed contact 22a and the movable contact 86b is induced toward the upper surface of the base 10.
An arc generated between the fixed contact 23a and the movable contact 87a is 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 22a and the movable contact 86b which face each other and an arc generated between the fixed contact 23a and the movable contact 87a which face each other can be induced in the predetermined directions by three permanent magnets. Accordingly, the electromagnetic relay according to this embodiment has an advantage that the number of parts can be reduced compared to the prior art.
By inserting the first permanent magnet 30 and the auxiliary yoke 31 into the notched grooves 17 formed on the base respectively, the auxiliary yoke 31 is positioned so as to be disposed adjacently to the first permanent magnet 30. The second permanent magnet 32 is housed in the recessed portion 18 formed on the base.
According to this embodiment, the first and second permanent magnets 30, 32 and the auxiliary yokes 31 are assembled from the lower surface of the base 10 and hence, it is possible to prevent the deterioration of the first and second permanent magnets 30, 32 and the auxiliary yoke 31 caused by a generated arc. Further, a thickness of the base 10 can be effectively utilized and hence, it is possible to provide a space saving electromagnetic relay.
It is not always necessary to assemble all of the first permanent magnets 30, the auxiliary yokes 31, and the second permanent magnet 32 from the lower surface of the base 10. These parts may be assembled from the upper surface of the base 10 when necessary.
The permanent magnets or, the permanent magnet and the auxiliary yokes may be disposed behind the fixed contacts 21a to 24a.
The above-mentioned auxiliary yoke 31 may not be limited to a rectangular plate-like magnetic member. For example, the auxiliary yoke 31 may have an approximately L shape as viewed in a front view (
The above-mentioned auxiliary yoke 31 may be formed of a rectangular plate-like magnetic member where corner portions are chamfered (
In the arc extinguishing space 19, for efficiently extinguishing a generated arc by rapid cooling, for example, an arc cut-off member 100 shown in
The arc cut-off member 100 is formed by bending a strip-shaped metal plate into an approximately J-shape in cross section. On a front surface of the arc cut-off member 100, a plurality of projections 101 having an approximately triangular shape are formed in a projecting manner. The projections 101 are formed so as to increase a rapid cooling effect by increasing a contact area with an arc. Ribs 102 are bent and raised from both side edge portions at the front surface of the arc cut-off member 100 such that the ribs 102 face each other, and ribs 103 are also bent and raised from both side edge portions at a bottom surface of the arc cut-off member 100 such that the ribs 103 face each other. The ribs 102, 103 are provided for preventing a generated arc from leaking out from the arc extinguishing space 19.
As another arc cut-off member 100, for example, as shown in
As shown in
The spool 41 is configured such that a through hole having a rectangular cross section is formed in a trunk portion 44 having flange portions 42, 43 on both ends thereof, and an insulation rib 46 is formed on an outward facing surface of one flange portion 42 such that the insulation rib 46 projects sideward. Engaging holes 47 are formed in both side edge portions of the other flange portion 43 of the spool 41, and relay clips 50 engage with the engaging holes 47 respectively thus preventing the removal of the spool 41 (
The coil 51 is wound around the trunk portion 44, and lead lines of the coil 51 are bound to binding portions 50a (
The iron core 52 is formed by stacking a plurality of plate-like magnetic members having an approximately planar T-shape. The iron core 52 is made to pass through the through hole 45 formed in the spool 41, one end portion of the iron core 52 projecting from the through hole 45 forms a magnetic pole portion 53, and the other end portion 54 of the iron core 52 projecting from the through hole 45 is fixed by swaging to a vertical portion 57 of the yoke 55 having an approximately L shaped cross section described later.
The yoke 55 is formed of a magnetic plate bent in an approximately L-shape in cross section. An engaging projection 56a is formed at the center of a horizontal portion 56 by bending and raising, and support projections 56b are formed on both side edge portions of a distal end of the horizontal portion 56 by cutting. The yoke 55 is formed into a shape which allows press-fitting of a lower end portion 57a of the vertical portion 57 into the press-fitting hole 14 formed in the base 10.
As shown in
By making the notched portions 62 engage with the support projections 56b of the yoke 55 and by connecting the engaging projection 61 to the engaging projection 56a of the yoke 55 by way of a restoring spring 63, the movable iron piece 60 is rotatably supported by the yoke 55.
Movable contact pieces 80, 81 have an approximately T shape as viewed 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 way of lining members 84, 85 having conductivity. By substantially increasing cross-sectional areas of the large width portions 82, 83, the lining members 84, 85 can reduce electric resistance thus suppressing the 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
The electromagnet block 40 on which the movable contact pieces 80, 81 are mounted is housed in the base 10, and the flange portion 42 of the spool 41 is placed on the stepped portion 13 of the base 10. The lower end portion 57a of the yoke 55 is press-fitted into the press fitting hole 14 formed in the base 10 thus positioning the yoke 55. Accordingly, the relay clips 50 of the electromagnet block 40 clamp the connecting portion 25a of the coil terminal 25 (
To be more specific, at least either one of the insulation ribs 46, 72 is disposed such that the insulation ribs 46, 72 intercept a straight line which connects the fixed contact 22a, 23a or the fixed contact terminal 22, 23 with the magnetic pole portion 53 with a shortest distance. Accordingly, a clearance distance from the magnetic pole portion 53 of the iron core 52 to the fixing contact 22a, 23a becomes long so that high insulating property can be acquired.
Further, the insulation rib 46 may be disposed such that the insulation rib 46 intercepts a straight line which connects the fixed contact 22a, 23a or the fixed contact terminal 22, 23 with the magnetic pole portion 53 with a shortest distance, and the insulation rib 72 may be disposed such that the insulation rib 72 intercepts a straight line which connects a distal edge portion of the insulation rib 46 and the magnetic pole portion 53 with a shortest distance. With such an arrangement, a spatial distance from the magnetic pole portion 53 of the iron core 52 to the fixed contact 22a, 23a can be increased so that higher insulating property can be acquired.
It is preferable that a length of the insulation rib 46 which projects from the outward facing surface of the flange portion 42 be shorter than a distance from the outward facing surface of the flange portion 42 to the distal end of the fixed contact 22a, 23a. This is because when a length of the insulation rib 46 is longer than a distance from the outward facing surface of the flange portion 42 to the distal end of the fixed contact 22a, 23a, there is a possibility that an operation of the movable contact piece 80, 81 is obstructed. Another reason is that arcs which are respectively generated between the fixed contacts 22a, 23a and the movable contacts 86b, 87a are liable to impinge on the insulation rib 46 so that the insulation rib 46 is liable to be deteriorated. Accordingly, the more preferred length of the insulation rib 46 is the length from the outward facing surface of the flange portion 42 to the outward facing surface of the fixed contact terminal 22, 23.
As shown in
With such a configuration, when the cover 90 is fitted on the base 10 to which the electromagnet block 40 is assembled, the engagement receiving portions 92 of the cover 90 engage with the engaging claw portions 10a of the base 10 so that the cover 90 is fixed to the base 10. Then, the position restricting ribs 93 are brought into contact with the horizontal portion 56 of the yoke 55 so that lifting of the electromagnet block 40 can be restricted. Next, by hermetically sealing the base 10 and the electromagnet block 40 by injecting and solidifying a sealing material (not shown in the drawing) on a lower surface of the base 10, an assembling operation is completed.
According to this embodiment, simultaneously with sealing of 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 and hence, the number of operation man-hours can be reduced whereby an electromagnetic relay can be obtained with high productivity.
Next, operation of the above-mentioned electromagnetic relay according to this embodiment is described.
When the electromagnet block 40 is not excited, as shown in
Then, when the coil 51 is excited due to applying of a voltage to the coil 51, the movable iron piece 60 is attracted to the magnetic pole portion 53 of the iron core 52 so that the movable iron piece 60 is rotated against a spring force of the restoring spring 63. Accordingly, the movable contact pieces 80, 81 are integrally rotated with the movable iron piece 60, the movable contacts 86a, 86b, 87a, 87b are brought into contact with the fixed contacts 21a to 24a and, thereafter, the movable iron piece 60 is attracted to the magnetic pole portion 53 of the iron core 52 (
Next, when applying of a voltage to the coil 51 is stopped, the movable iron piece 60 is rotated in a clockwise direction due to a spring force of the restoring spring 63, the movable iron piece 60 is separated from the magnetic pole portion 53 of the iron core 52 and, thereafter, the movable contacts 86a, 86b, 87a, 87b are separated from the fixed contacts 21a to 24a and are restored to an original state.
According to this embodiment, as shown in
According to this embodiment, only with the use of the first permanent magnet 30, the generated arc 110 can be induced to an area behind the fixed contact 21a, 24a and can be extinguished. However, by disposing the auxiliary yoke 31, the arc 110 can be induced to an area just behind the fixed contact 21a, 24a. Accordingly, the generated arc is extended to the area just behind the fixed contact 21a, 24a without being brought into contact with the inner surface of the cover 90 and hence, the arc 110 can be extinguished more efficiently.
Further, according to this embodiment, a dead space located behind the fixed contacts 21a, 24a is effectively used as the arc extinguishing space 19 and hence, the electromagnetic relay according to this embodiment has an advantage that large sizing of the device can be avoided.
It is needless to say that the shapes, the sizes, the materials, the arrangement, and the like of the first and second permanent magnets 30, 32 and the auxiliary yoke 31 are not limited to the above-mentioned values, and can be changed when necessary.
In the working example 1, an analysis is made on the directions and magnitudes of lines of a magnetic force when the first and second permanent magnets 30, 32 and the auxiliary yoke 31 are combined with each other.
As a result of the analysis, the directions of the lines of a magnetic force are described by vector lines (
In the working example 2, an analysis is made on the directions and the magnitudes of lines of a magnetic force when the first and second permanent magnets 30, 32 are disposed in the same manner as the above-mentioned working example 1 except for that the working example 2 is not provided with the auxiliary yoke 31.
As a result of the analysis, the directions of the lines of a magnetic force are described by vector lines (
By comparing the result of analysis described in
It is also confirmed how and to what extent lines of magnetic forces 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 analysis shown in
The present invention is not limited to a DC electromagnetic relay and may be applied to an AC electromagnetic relay.
In this embodiment, the case where the present invention is applied to the electromagnetic relay having four poles has been described. However, the present invention is not limited to such a case, and the present invention may be applied to an electromagnetic relay having at least one pole.
The present invention is not limited to an electromagnetic relay, and may be applied to a switch.
Number | Date | Country | Kind |
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2014-247347 | Dec 2014 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2015/080389 | 10/28/2015 | WO | 00 |