Patent Grant
6903639
1. Field of the Invention
This invention relates to an electromagnetic relay.
2. Description of the Related Art
A known electromagnetic relay employs a construction in which a coil block produced by winding a coil on a core through a spool and connecting the coil to coil terminals disposed at flanges of the spool is mounted to a base and a through-hole formed in the base is sealed under the state where each coil terminal protrudes from the through-hole (refer to patent reference 1, for example).
Patent Reference 1:
Microfilm of Japanese Utility Model Application No. 119979/1984 (Japanese Utility Model Laid-Open No. 35349/1986)
In the electromagnetic relay of the prior art described above, however, a space is defined between the coil block and the base and one of the ends of a moving iron plate is attracted to and departed from an attraction surface of the core exposed into this space. Therefore, a sealant entering through the through-hole is likely to reach the space and to invite an operation defect.
It is therefore an object of the invention to provide an electromagnetic relay capable of appropriately preventing invasion of a sealant.
To accomplish this object, the invention provides an electromagnetic relay in which a coil block formed by winding a coil on a core through a spool and connecting the coil to coil terminals disposed at flanges of the spool is mounted to a base and a through-hole formed in the base is sealed under the state where each coil terminal protrudes from the through-hole, wherein an attraction surface of the core is positioned on the side of the base so that a moving iron plate can be attracted and operated between the coil block and the base; and an increased thickness portion into which the coil terminal can be pushed is disposed in the flange of the spool, and a recess for storing a sealant entering through the through-hole is formed around the coil terminal in the increased thickness portion.
According to this construction, even when the sealant in an amount capable of sufficiently sealing the gap between the through-hole and the coil terminal is filled, the sealant is stored in the recess formed in the increased thickness portion of the spool and does not any more enter the inside.
The recess is preferably formed in such a fashion that its depth progressively increases in a direction of an outer diameter. For, the support state of the coil terminal at the increased thickness portion can be stabilized and invasion of the sealant can be more readily prevented.
A partition wall for preventing expansion of the sealant entering from the through-hole is preferably formed on the upper surface of the base because invasion of the sealant can be more readily prevented.
Ribs continuing the sidewall portions of the base are preferably used to constitute the partition wall because invasion of the sealant can be prevented while the flow of a resin for molding can be kept under a satisfactory state even when the base is formed to a reduced thickness.
When a taper surface is formed on the increased thickness portion of the spool and on the partition wall, the base and the coil block come into mutual surface contact with each other when the coil block is put on the base. According to this construction, positioning of the coil block becomes easier and invasion of the sealant can be prevented more reliably and desirably.
The recess described above is preferably formed in such a fashion that its capacity on the side opposite to the moving iron plate becomes greater. According to this construction, the flowing direction of the invading sealant becomes opposite to the moving plate.
FIG. 3(a) is a perspective view of a first fixed contact plate;
FIG. 3(b) is a perspective view of a moving contact plate;
FIG. 3(c) is a perspective view of a second fixed contact plate;
Preferred embodiments of the invention will be hereinafter explained with reference to the accompanying drawings.
An insulating wall 5 divides the base 1 into a coil block-fitting portion 6 and a contact switch mechanism-fitting portion 7 as shown in
The insulating wall 5 has a partition portion 8 and both side portions 9. Protuberance portions 10 are so formed at the center of the partition portion 8 as to extend in a vertical direction with a predetermined gap between them. The protuberance portions 10 reinforce the partition portion 8 and guide with their upper edge protuberance portions 10a a card 100 that will be later described. An auxiliary insulating wall 11 is formed at a lower part of each protuberance portion 10 in such a fashion as to define a recess in cooperation with the insulating wall 5. A guide groove 11a extending in the vertical direction is formed at the center of the inner surface of the auxiliary insulating wall 11. On the other hand, groove portions 9a and 9b extending in the vertical direction while their positions are deviated from each other are formed on the inner and outer surfaces of both side portions 9, respectively. The inner surface groove portion 9a guides a yoke 30 to be later described. The outer surface groove portion 9b is a recession for molding the base 1.
As particularly shown in
Incidentally, reference numeral 1a denotes a standoff. The standoff 1a forms a clearance with the bottom surface of the base when the electromagnetic relay is mounted to a printed board and eliminates influences of a solder at the time of soldering.
The contact switch mechanism-fitting portion 7 has contact plate push-in portions 18a, 18b and 18c at three positions as shown in FIG. 8.
The contact switch mechanism 2 includes a first fixed contact plate 19, a moving contact plate 20 and a second fixed contact plate 21 that are serially pushed into the contact plate push-in portions 18a, 18b and 18c from one of the ends 18a of these contact plate push-in portions 18a, 18b and 18c.
The first fixed contact plate 19 is substantially flat as shown in FIG. 3(c) and has at its upper end the first fixed contact 22 and at its lower end a protuberance 19a to be pushed into the contact plate push-in portion 18. Terminal portions 19b and 19c extend downward from both sides of the first fixed contact plate 19.
The moving contact plate 20 has on both surfaces of its upper end a moving contact 23 having a contact surface with respect to the fixed contacts 22 and 26 as shown in FIG. 3(b). Card acceptance portions 24a and 24b extending obliquely vertically are formed at the upper edge of the moving contact plate 20. A protruding distance of the card acceptance portions 24a and 24b is set to a value at which the card 100 to be later described does not fall off even when the moving contact plate 20 undergoes elastic deformation. The intermediate part of each card acceptance portion 24a, 24b constitutes an escape portion 25 lest it becomes an obstacle when the second fixed contact plate 21 is inserted from above. Push-in protuberance portions 20a are formed at the lower end of the moving contact plate 20 in the same way as the first fixed contact plate 19. Terminal portions 20b and 20c extend from both sides of the moving contact plate 20. The center portion is bent into a crank shape and a slit 20d is formed at the center so that the moving contact plate 20 can easily undergo elastic deformation.
The second fixed contact 26 is fitted and fixed to the upper end of the second fixed contact plate 21. The second fixed contact plate 21 is bent into a crank shape from its part in the proximity of the second fixed contact 26. Push-in protuberance portions 21a are formed at the lower end of the second fixed contact plate 21 in the same way as both contact plates 19 and 20. The lower portion of the second fixed contact plate 21 below the push-in protuberance portions 21a is bent substantially at right angles in the horizontal direction and terminal portions 21b and 21c extend downward from both ends of the bent portion. The second fixed contact plate 21 is fitted to the base 1 under the state where it is guided by the guide groove 11a of the auxiliary insulating wall 11. The auxiliary insulating wall 11 secures desired insulating performance (creep distance) with the moving contact plate 20 when the moving contact 23 is spaced apart from the second fixed contact 26.
The coil block 3 is obtained by winding a coil 29 onto a core 27 through a spool 28 as shown in
A yoke 30 is fixed to the upper end of the core 27. A flange-like lower end of the core 27 operates as an attraction surface 27a. The yoke 30 is constituted by a substantially L-shaped magnetic material and has an opening 30a into which the core 27 is fitted and fixed by inserting therein, at the center of one of its ends. An anchor acceptance portion 30b for fitting a hinge spring 31 is formed at a side edge of the other end of the yoke 30. The other end of the yoke 30 operates as a support point for rotation. A substantially L-shaped moving iron plate 32 is supported under the state where it is held by the hinge spring 31 in such a fashion that a bent portion 33 can freely rock. One of the ends of the moving iron plate 32 is an attracted portion 34 that is attracted to the attraction surface 27a of the core 27, and an anchor portion 35a is formed at the upper end of a reduced width portion 35 at the other end of the moving iron plate 32. The hinge spring 31 includes an anchor portion 31a anchored to the anchor acceptance portion 30b of the yoke 30 described above and a rectangular pressure contact portion 31b into which the reduced width portion 35 of the moving iron plate 32 is fitted and which comes into pressure contact with the bent portion 33. The rectangular pressure contact portion 31b comes into pressure contact with a step portion 32a and a curved surface 32b of the bent portion 33 of the moving iron plate 32 and urges the moving iron plate 32 counter-clockwise in
The card 100 is interposed between the anchor portion 35a of the moving iron plate 32 and the card acceptance portion 24 of the moving contact plate 20. As shown in
As shown in
Preferably, the ring-like recess 43 is formed in such a fashion that its depth progressively increases towards the outer diameter side. In this way, the length of the terminal hole 41a can be sufficiently secured, the push-in margin of the coil terminal 42 can be secured and the push-in state can be stabilized. Alternatively, the ring-like recess 43 may be constituted in such a fashion that it is deeper or broader on the side opposite to the region in which the moving iron plate 32 rotates. According to this construction, the fluidization direction of the inflowing sealant can be directed to the side opposite to the region described above. Even when the sealant fluidizes beyond the ring-like recess 43, for example, adverse influences are not exerted on the operation of the moving iron plate 32.
The increased thickness portion 41 preferably has a construction capable of coming into surface contact on its slope with the partition wall 12. In other words, a slope that progressively inclines inwards towards the bottom surface is formed in the increased thickness portion 41. On the other hand, a slope is formed on the partition wall 12 in such a fashion as to gradually expand the open area of the push-in acceptance portion 17. In consequence, when the increased thickness portion 41 is pushed into the push-in acceptance portion 17, this arrangement prevents their mutual interference and makes it possible to smoothly conduct the push-in operation. It becomes also possible to reliably prevent the inflow of the sealant by bringing the slope surfaces into mutual surface contact without much improving dimensional accuracy.
The coil 29 is wound on a drum portion of the spool 28 and both of its ends are wound on the coil terminal 42, respectively.
Referring to
An assembling method of the electromagnetic relay described above will be subsequently explained.
The coil block 3 is formed in a separate step. In other words, the coil 29 is wound on the core 27 through the spool 28 as shown in FIG. 4 and both ends of the coil 29 are wound on the coil terminals 42 pushed into and fixed to the increased thickness portion 41, respectively. One of the ends of the yoke 30 is fixed to the upper end of the core 27 and the moving iron plate 32 is arranged at the other end of the yoke 30 in such a fashion as to be capable of rocking. The moving iron plate 32 is fitted to the yoke 30 through the hinge spring 31 and is urged to come away from the attraction surface 27a of the core 27. The coil block 3 shown in
The moving contact plate 20 and the first and second fixed contact plates 19 and 21 are pushed into and fixed to the base 1 as shown in FIG. 9 and the completed coil block 3 is assembled to the base 1 as shown in
After the push-in and fixing operation of the coil block 3 and each contact plate 19, 20, 21 to the base 1 is completed, the anchor holding portion 36 of the card 100 is anchored to the anchor portion 35a of the moving iron plate 32 as shown in FIG. 12. In other words, when the anchor holding portion 36 is pushed from the side of the anchor portion 35a, the flexible holding plate 39 undergoes elastic deformation and then returns to its original shape. In consequence, the flexible holding plate 39 and the contact plate 38 hold the anchor portion 35a. After the moving contact plate 20 is allowed to undergo elastic deformation and then to return to its original shape, the reduced thickness portion 37a of the card 100 is positioned between the upper and lower card acceptance portions 24 formed at the upper end of the moving contact plate 20. As shown in
After fitting of the card 100 is completed, power is applied to the coil 29 through the coil terminals 42 and the coil block 3 is magnetized and demagnetized to thereby rotate the moving iron plate 32. Whether or not the moving iron plate 32 is appropriately attracted to the attraction surface 27a of the core 27 is confirmed with eye or by use of laser through the notch portion 14 formed in the base 1. Whether or not switching of the contacts is appropriately conducted is also confirmed at this time to inspect the absence/existence of an operation defect. When any operation defect exists, the shape of the moving contact plate 20 is deformed for adjustment, for example.
When the operation is satisfactory, the case 4 is fitted to the base 1 as shown in
The electromagnetic relay is completed in the manner described above. However, the gas vent hole 44 formed in the case 4 may well be used while left open or under the sealed state after it is thermally sealed depending on the environment of use. Even when impact force acts on the internal constituent components due to fall, or the like, no problem occurs because each component is firmly fixed to the base 1. The card 100, in particular, has the simple construction in which the moving iron plate 32 and the moving contact plate 20 are merely interconnected. One of the ends of the card is interconnected to the moving iron plate 32 through the anchor holding portion 36 and the other end guides the reduced thickness portion 37a of the push-in portion 37 within the range in which the moving contact plate 20 can undergo deformation. The upper end protuberance portion 10a formed on the insulating wall 5 of the base 1 is positioned between the contact plate 38 and the flexible holding plate 39 constituting the anchor holding portion 36 and the second protuberance portion 46 formed on the case 4 is positioned above the card 100. Therefore, even when any impact force operates, the card 100 does not fall off.
Next, the operation of the electromagnetic relay described above will be explained.
While power is not applied to the coil 29 and the coil block 3 is demagnetized, the moving iron plate 32 rotates counter-clockwise in
When power is applied to the coil 29 and the coil block 3 is excited, one of the ends of the moving iron plate 32 is attracted to the attraction surface 27a of the core 27 and the moving iron plate 32 rotates clockwise in
In the embodiment described above, the fixed contact plates 19 and 20 are disposed on both sides of the moving contact plate 20, but they may be disposed on only one side. In other words, it is possible to employ a construction in which only the second fixed contact plate 21 is not disposed but the rest of the constituent components are as such used as shown in FIG. 16.
In the embodiment described above, the guide plate 37b of the card 100 is disposed separately from the card reinforcement ribs 40. However, it is also possible to employ a construction in which the card reinforcement ribs 40 operate also as the guide plate 37b. In other words, the card reinforcement ribs 40 positioned on both sides guide both sides 9 of the upper card acceptance portion 24. At least one each card acceptance portion 24 of the moving contact plate 20 may well exist at the upper and lower positions. In the construction in which the second fixed contact plate 21 is not disposed, the card acceptance portion 24 may well be formed at the center.
As is obvious from the explanation given above, the recess is formed in the increased thickness portion of the spool in the invention. Therefore, the sealant entering from the through-hole of the base does not enter the inside beyond the recess, and does not exert adverse influences on the operation portion even in the construction in which the moving iron plate is operated inside the space defined between the coil block and the base.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2002-325242 | Nov 2002 | JP | national |
| Number | Name | Date | Kind |
|---|---|---|---|
| 5021760 | Krubsack et al. | Jun 1991 | A |
| 5696475 | Yoshitani et al. | Dec 1997 | A |
| 20040084649 | Yoshimura et al. | May 2004 | A1 |
| Number | Date | Country | |
|---|---|---|---|
| 20040130419 A1 | Jul 2004 | US |
