Patent Application
20130241679
The present invention relates to an electromagnetic relay.
Conventionally, as an electromagnetic relay, there is known an electromagnetic relay having a configuration in which a fixed terminal is latched and attached to each spool of each electromagnet block in a press-fitted manner and each flange is connected in parallel to each other so that the electromagnet blocks may be integrally combined (see, for example, Japanese Unexamined Patent Publication No. 2000-315448).
However, in such a conventional electromagnetic relay, when the electromagnetic relay is miniaturized, a movable contact piece needs to be reduced in width dimension because of its structural characteristic. This also brings about the reduction in size of the electromagnet. Accordingly, in order to secure the same magnitude of attracting force with the electromagnet of the reduced size, it is necessary to increase the energizing amount flowing to a coil. For this reason, the calorific value from the coil increases. In this case, when the movable contact piece is decreased in the width and the surface area as described above, the heat generated from the coil may not be sufficiently discharged to the outside. As a result, it is difficult to secure the desired attracting force of the electromagnet, which makes it difficult to miniaturize the conventional electromagnetic relay.
The present invention has been devised to solve the problems described above, and an object thereof is to provide an electromagnetic relay which can sufficiently dissipate the heat generated from a coil to secure desired attracting force even when the electromagnetic relay is miniaturized.
In accordance with one aspect of the invention, in order to achieve the above object, there is provided an electromagnetic relay including: a plurality of electromagnet blocks, each block including an electromagnet configured by winding a coil around an iron core via a spool, a yoke having a to-be-connected portion which is to be connected to a connection portion of one end of the iron core and a rising portion extending laterally from a magnetic pole portion of the iron core, a movable iron piece turnably supported by a distal end of the rising portion of the yoke and attracted to the magnetic pole portion of the iron core by magnetization of the electromagnet; and a contact switching mechanism including a movable contact piece attached to the movable iron piece and provided with a movable contact, and a fixed terminal attached to the spool to integrally combine the plurality of electromagnet blocks and provided with a fixed contact arranged to be brought into contact with and move away from the movable contact, wherein the movable contact piece includes a contact attaching portion to which the movable contact is attached and a first fixed portion that is attached to the movable iron piece, and the first fixed portion is brought into surface contact with the movable iron piece and is substantially equal in width dimension to the movable iron piece.
With this configuration, the surface area of the movable contact piece may be increased in the portion where the movable iron piece is in surface contact with the movable iron piece. Therefore, the heat generated due to the energizing of the coil may be sufficiently dissipated via a portion ranging from the movable iron piece to the first fixed portion of the movable contact piece.
In accordance with another aspect of the invention, in order to achieve the above object, there is provided an electromagnetic relay including: a plurality of electromagnet blocks, each block including an electromagnet configured by winding a coil around an iron core via a spool, a yoke having a to-be-connected portion which is to be connected to a connection portion of one end of the iron core and a rising portion extending laterally from a magnetic pole portion of the iron core, a movable iron piece turnably supported by a distal end of the rising portion of the yoke and attracted to the magnetic pole portion of the iron core by magnetization of the electromagnet; and a contact switching mechanism including a movable contact piece attached to the movable iron piece and provided with a movable contact, and a fixed terminal attached to the spool to integrally combine the plurality of electromagnet blocks and provided with a fixed contact arranged to be brought into contact with and move away from the movable contact, wherein the movable contact piece includes a contact attaching portion to which the movable contact is attached and a second fixed portion that is attached to the rising portion of the yoke, and the second fixed portion is brought into surface contact with the yoke and is substantially equal in width dimension to the yoke.
With this configuration, the surface area of the movable contact piece may be increased in the portion where the movable iron piece is in surface contact with the yoke. Therefore, the heat generated due to the energizing of the coil may be sufficiently dissipated via a portion ranging from the yoke to the second fixed portion of the movable contact piece.
Preferably, the respective spools are provided side by side at a position near the other end of the iron core where the magnetic pole portion is arranged, each of the flanges has a press-fitting recess at one side thereof in a direction of parallel arrangement, the fixed terminal has a plurality of press-fitted portions to be press-fitted into the press-fitting recesses of the respective spools, and the press-fitted portions are formed by cutting and raising portions of the fixed terminals in the direction of parallel arrangement.
With this configuration, the range, where the movable contact piece is arranged, in the flange may be provided so as to avoid only the press-fitting recess formed at one side in the direction of the parallel arrangement. Therefore, the range occupied by the movable contact piece may be increased. In addition, since the press-fitted portion formed in the fixed terminal is formed by cutting and raising, material punching can be performed without waste of material so that an increase in cost can be suppressed.
Preferably, the movable contact piece is made of an elastic material with a high thermal conductivity compared with the movable iron piece and the yoke.
With this configuration, the heat generated due to the energizing of the coil may be more efficiently dissipated via the movable contact piece.
According to the present invention, since the surface area of the movable contact piece where the movable contact piece is in surface contact with a component which constitutes the electromagnet block may be increased, the heat generated due to the energizing of the coil may be effectively dissipated. As a result, it becomes possible to prevent the deterioration of the operating characteristic attributable to the increase in temperature.
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Note that in the description below, terms that refer to specific directions and positions (for example, terms including “upper”, “lower”, “side”, and “end”) are used if necessary. The purpose of using those terms is to help one better understand the present invention referring to the drawings, but the technical scope of the present invention should not be limited by meanings of those terms. The description made hereinbelow represents just an essential example of the present invention and is not intended to limit the present invention, applications of the present invention, and uses of the present invention.
As illustrated in
The iron core 4 is formed in a bar shape made of a magnetic material and includes a trunk portion 9 having a rectangular cross-section, a flange-shaped magnetic pole portion 10 formed at an upper end portion of the trunk portion 9, and a connection portion 11 that is formed at a lower end of the trunk portion 9 and has a small cross-sectional area compared with the trunk portion 9. The magnetic pole portion 10 attracts the movable iron piece 8. The connection portion 11 is fitted into a connection hole 32 formed in the yoke 7 described below so as to be integrally combined.
The spool 5 is a component obtained by performing a molding process with a synthetic resin material and is configured such that flanges 13 and 20 which are substantially rectangular in a plan view are respectively provided at upper and lower end portions of a cylindrical portion 12. A central hole of the cylindrical portion 12 is formed to have an internal surface formed along the trunk portion 9 of the iron core 4.
A recess 14 in which the magnetic pole portion 10 of the iron core 4 is to be arranged is formed in the upper surface of the upper end-side flange 13 of the spool 5 so as to surround an opening of the central hole. There are four protrusions 15 on the bottom surface of the recess 14, especially around the opening of the central hole. The lower surface of the magnetic pole portion 10 is in contact with these protrusions 15 so that the position of the magnetic pole portion 10 in the vertical direction may be determined. Both ends of a first side of the upper end-side flange 13 (one side in the longitudinal direction) project outward, and the yoke 7 is arranged between the projected end portions. A step portion 16 is provided in the middle portion of a second side of the upper end-side flange 13 (the opposite side in the longitudinal direction), and a notch 17 is formed therein. A portion (contact stand) of a second fixed terminal 35 described below is located in the step portion 16, and a second fixed contact 53 described below is located in the notch 17. One flank portion of the second side of the upper end-side flange 13 is relatively thick, and a groove-shaped engagement socket 18 is formed in the middle portion in the vertical direction. A distal end portion of the first fixed terminal 34 is press-fitted into the engagement socket 18. The other flank portion of the second side of the upper end-side flange 13 projects upward, and a press-fitting recess 19 is formed in the upper surface thereof. The press-fitting recess 19 is substantially rectangular in a plan view, and a first press-fitted portion 47 of the first fixed terminal 34 is press-fitted into the press-fitting recess 19.
The flange 20 provided at the lower end of the spool 5 protrudes from the upper end-side flange 13 toward the second side. Terminal attaching portions 21, each formed of a rectangular hole passing through the upper and lower surfaces and a notch, are formed at both sides of the projected portion, respectively. Formed between these terminal attaching portions 21 are an insulating wall portion 22 projecting upward and an engagement groove 23 which starts from one end of a lower end-side groove and extends toward the insulating wall portion 22. An engagement recess 24 is formed in the end face of the insulating wall portion 22 which is near the engagement groove. As illustrated in
The coil 6 is wound around the trunk portion 9 of the spool 5, and extension lines of the coil 6 are wound around and attached to a pair of coil terminals 27, which are respectively press-fitted and fixed to the lower end-side flange 20 of the spool 5. Each of the coil terminals 27 includes a winding portion 28 around which the extension line of the coil 6 is wound, and a terminal portion 29. A base portion of the winding portion 28 is press-fitted into and fixed by a rectangular hole of the terminal attaching portion 21 and an upper portion of the terminal portion 29 is press-fitted into and fixed by the notch.
The yoke 7 is obtained by bending a plate member of a magnetic material into an approximately L shape formed of the to-be-connected portion 30 and a rising portion 31. The to-be-connected portion 30 is provided with a connection hole 32 to which the connection portion 11 of the iron core 4 is connected. The rising portion 31 is provided with riveting projections 31a formed at a predetermined interval in a widthwise direction.
The movable iron piece 8 is a plate member of a magnetic material which is chamfered at corners of the distal end thereof so that the distal end of the movable iron piece 8 has a narrower width than the other portion. Supporting pieces 8a project from both ends of the rear end face of the movable iron piece 8, respectively, and a slot 8b extending from the upper surface to the lower surface is provided between the supporting pieces 8a. Riveting projections 8c are formed at a predetermined interval on the upper surface of the movable iron piece 8. The movable iron piece 8 is turnably supported by the upper end of the rising portion 31 of the yoke 7 so as to turn about the position (the upper end corner of the rising portion 31 of the yoke 7) where the lower surface of the movable iron piece 8 and the supporting piece 8a cross each other. In addition, a magnetic closed loop is formed by the iron core 4, the yoke 7, and the movable iron piece 8 so that the leakage of magnetic flux may be controlled.
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Next, a method of assembling the magnetic relay will be described.
The coil 6 is wound around the spool 5, the pair of coil terminals 27 are press-fitted into and attached to the respective terminal attaching portions 21 of the lower end-side flange 20, and the extension lines of the coil 6 are wound and attached thereto, respectively. The to-be-connected portion 30 of the yoke 7 is inserted into the relief recess 25 in a lateral direction via the opening formed in the lower end-side flange 20 of the spool 5, and the rising portion 31 of the yoke 7 is positioned at the side of the wound coil 6. In addition, the iron core 4 is inserted into the central hole of the spool 5 from above, and the connection portion 11 at the distal end of the iron core 4 is fitted into the connection hole 32 of the yoke 7. The movable contact piece 33 is riveted and fixed to the movable iron piece 8, and the movable contact piece 33 is also riveted and fixed to the yoke 7 so that the electromagnet block 1 is completed. In this state, the movable iron piece 8 is kept away from the magnetic pole portion 10 of the iron core 4 due to the spring force of the movable contact piece 33.
Thus, two completed electromagnet blocks 1 are installed side by side, and both are integrally combined by the second fixed terminal 35. That is, the second fixed terminal 35 is assembled from the side of the pair of electromagnet blocks 1 arranged side by side. At this time, the upper-side second press-fitted portion 54 of the second fixed terminal 35 is press-fitted into the engagement socket 18 formed in the upper end-side flange 13 of the spool 5, and the lower-side second press-fitted portion 55 is press-fitted into the engagement recess 24 via the engagement groove 23 formed in the lower end-side flange 20.
In this state, the intermediate portion 56 of the second fixed terminal 35 is positioned in the recess 26a formed in the lower end-side flange 20 of one of the electromagnet blocks 1, and the intermediate portion 56 is not projected from the side of the spool 5.
Moreover, the connection of the electromagnet blocks 1 becomes stronger by the first fixed terminal 34. That is, the first fixed terminal 34 is assembled to the electromagnet blocks 1 integrally combined, from above. At this time, the first press-fitted portion 47 is press-fitted into the press-fitting recess 19 formed in the upper end-side flange 13 of the spool 5. In this state, the intermediate portion 48 of the first fixed terminal 34 is positioned in the recess 26b formed in the lower end-side flange 20 of the other one of the electromagnet blocks 1, and the intermediate portion 48 is not projected from the side of the spool 5.
In this way, since the pair of electromagnet blocks 1 is integrally combined not only by the second fixed terminal 35 assembled from the side but also by the first fixed terminal 34 assembled from above, the combined state is stable. Thereafter, the case 3 is put on the combined electromagnet blocks 1, and as a result, the electromagnetic relay is completed.
Next, the operation of the magnetic relay will be described. Under a condition in which the coil 6 is not energized and the electromagnet blocks 1 are not yet magnetized, the movable iron piece 8 is turned about the upper end corner of the yoke 7 due to the spring force of the movable contact piece 33 such that the movable iron piece 8 moves away from the magnetic pole portion 10 of the iron core 4. Next, the movable contact 40 is brought into contact with the first fixed contact 46.
Here, when the coil 6 is energized and the electromagnet block 1 is magnetized, the movable iron piece 8 is attracted to the magnetic pole portion 10 of the iron core 4 and is turned against the spring force of the movable contact piece 33. Therefore, the movable contact 40 moves away from the first fixed contact 46, and comes into contact with the second fixed contact 53.
Incidentally, when the coil 6 is energized and thus the electromagnet blocks 1 are magnetized, there is a concern that heat is generated from the coil 6 and the operating characteristic be deteriorate due to the rise in temperature in some cases. In this case, in the electromagnetic relay having the above-described configuration, the surface area of the movable contact piece 33 is increased to the extent that approximates almost the maximum area at two places of the attaching portion of the movable iron piece 8 and the attaching portion of the yoke 7. For this reason, the heat generated from the coil 6 is transferred through the movable iron piece 8 and the yoke 7 so that it is sufficiently dissipated from the movable contact piece 33. Therefore, the electromagnet blocks 1 are not overheated and deteriorated in the operating characteristic.
The present invention is not limited to the configuration described in the preferred embodiment and can be modified in various ways.
For example, although two electromagnet blocks 1 are provided side by side in the above-described embodiment, three or more electromagnet blocks may be also provided. In this case, the first fixed terminal 34 and the second fixed terminal 35 may be further extended, and the contact stands and the press-fitted portions are increased in number so as to correspond to the increased number of the electromagnet blocks 1.
There has thus been shown and described an electromagnetic relay using the same which fulfills all the objects and advantages sought therefore. Many changes, modifications, variations and other uses and applications of the subject invention will, however, become apparent to those skilled in the art after considering this specification and the accompanying drawings which disclose the preferred embodiments thereof. All such changes, modifications, variations and other uses and applications which do not depart from the spirit and scope of the invention are deemed to be covered by the invention, which is to be limited only by the claims which follow.
Although the invention has been described in detail for the purpose of illustration based on what is currently considered to be the most practical and preferred embodiments, it is to be understood that such detail is solely for that purpose and that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. For example, it is to be understood that the present invention contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2012-059052 | Mar 2012 | JP | national |
