Electromagnet Relay With Specific Housing Structure

The present invention relates to an electromagnet relay, or more in particular to a small-sized or miniature electromagnet relay (hereinafter referred to as "relay") of a flat-type or the like which may be mounted direclty on a printed-circuit board.

The relay mounted on a printed-circuit board is required to be as compact and low in mounting height as possible in view of the positional relation with the other electronic parts including ICs.

An object of the present invention is to provide a relay which has been reduced in size by eliminating the useless space in the arrangement of the related members thereof.

Another object of the present invention is to provide a miniature relay which is low in height in the mounted condition, or particularly a miniature relay of which, when mounted with a socket, the height from the printed-circuit board is substantially the same as that of the relay proper, and which, when mounted directly on the printed-circuit board, is lower than the relay proper.

Still another object of the present invention is to provide a miniature relay which can be mounted on the printed-circuit board very easily in assembly work.

FIG. 1 is a perspective view from under a conventional relay.

FIGS. 2 and 3 are diagrams showing mounted conditions of the relay of FIG. 1.

FIG. 4 is an exploded perspective view showing an embodiment of the relay according to the present invention.

FIG. 5 is a longitudinal front view showing the assembled condition of the relay of FIG. 4.

FIG. 6 is a longitudinal side view of the relay shown in FIG. 5.

FIG. 7 is a longitudinal sectional view in the deassembled condition taken substantially at the central part of the relay of FIG. 6 and showing the electromagnet relay-contact assembly and the bottom part of the housing thereof.

FIG. 8 is a longitudinal sectional view showing an end of the electromagnet relay contact assembly.

FIG. 9 is a partial front view of the end shown in FIG. 8.

FIG. 10 is a longitudinal sectional view showing a dismantled relay armature and an actuator.

FIG. 11 is a perspective view showing the dismantled relay armature and actuator shown in FIG. 10.

FIG. 12 is a perspective view showing the underside of the relay of FIG. 5.

FIG. 13 is a partial perspective view showing another embodiment of the support for the relay armature.

FIG. 14 is a perspective view showing the underside of another embodiment of the relay according to the present invention.

FIG. 15 is a longitudinal sectional view showing the relay of FIG. 14.

FIG. 16 is a perspective view showing another embodiment of the housing according to the present invention.

FIG. 17 is a perspective view showing another embodiment of the contact block.

FIG. 18 is a perspective view of a socket for mounting the relay according to the present invention.

FIG. 19 is a longitudinal sectional view showing the condition in which the relay according to the present invention is mounted on the socket.

FIGS. 20 and 21 are longitudinal sectional views showing the relay according to the present invention directly mounted on the printed-circuit board.

Prior to explanation of preferred embodiments of the present invention, disadvantages of conventional relays will be described with reference to FIGS. 1 to 3 for facilitating the understanding of the present invention.

As shown in FIGS. 1 to 3, a conventional relay of this type has a substantially flat bottom wall b from which terminals a are protruded. The bottom wall surface b is usually covered with a resin material to seal the relay. When this relay is mounted directly on a printed-circuit board P, the very height of the relay T represents the mounting height (FIG. 3). In the case where the relay is mounted through a socket d, on the other hand, the relay height T plus the socket height t represents the mounting height. In relation with the other electronic parts such as ICs, it is required by users that the mounting height of the relay also be lowered. Being covered with resin at the whole bottom wall surface b, the conventional relay has such further drawbacks that the bottom surface is apt to become irregular, that a large amount of resin is requires, and that the resin portion does not dry easily because of its large amounts.

Preferred embodiments of the present invention will be now described in detail below with reference to FIGS. 4 to 21. In FIGS. 4 to 12, reference numeral 1 shows a core, numeral 2 an electromagnetic coil wound around a bobbin 3, numeral 4 a yoke bent in the shape of . An end 1a of the core 1 inserted into the central hole 3a of the bobbin 3 is secured to the vertical portion 4a of the yoke 4, so that the yoke 4, the bobbin 3 and the core 1 are integrated, thus constituting an electromagnet block A. The horizontal portion 4b of the yoke 4 is extended in parallel to the core 1 and has an end 4c thereof positioned correspondingly to the other end 1b of the core 1. Numerals 5, 6 show insulating mounts made of a resin material, on which coil terminals 7, 8, contact common terminals 9, 10, normally-closed contact terminals 11, 12 and normally-open contact terminals 13, 14 are molded respectively integrally in parallel thereby to constitute contact blocks B and C respectively. The contact blocks B and C are arranged on the respective sides of the electromagnet block A, so that the coil terminals 7 and 8, the contact common terminals 9 and 10, the normally-closed contact terminals 11 and 12, and the normally-open contact terminals 13 and 14 are respectively positioned in opposed relation to each other. The normally-closed contact terminals 11, 12 and the normally-open contact terminals 13, 14 have stationary contacts 11a, 12a and 13a, 14a respectively formed at the upper ends thereof bent toward each other. The normally-closed stationary contacts 11a, 12a and the normally-open stationary contacts 13a, 14a are positioned at different heights. In other words, the normally-closed contacts 11a, 12a are different in height from the normally-open contacts 13a, 14a. Numerals 15, 16 show movable contact members of an elastic conductive material including lower ends 15a and 16a respectively secured by spot welding or like means to the upper end bent portions 9a and 10a of the common terminals 9 and 10 respectively, and free-end contacts 15b and 16b interposed between the normally-closed contacts 11a, 12a and the normally-open contacts 13a, 14a respectively. The free-end contacts 15b and 16b are normally in contact with the normally-closed contacts 11a and 12a respectively. The upper ends of the coil terminals 7 and 8 are connected to the coil ends of the electromagnetic coil 2 respectively. The contact blocks B and C thus constructed are mounted on the sides of the electromagnet block A. For the purpose of mounting of the contact blocks B and C, longitudinal slots 5a and 6a are formed in the inner upper end parts of the insulating mounts 5 and 6, and tongues 5c and 6c having protrusions 5b and 6b respectively underside are protruded from the part substantially above the central part of the slots 5a and 6a. The yoke 4 has holes 4d and 4e formed in the vicinity of the side edges of the horizontal part 4b thereof. With the side edges of the horizontal part 4b of the yoke 4 fitted into the slots 5a and 6a of the insulating mounts 5 and 6 respectively and with the inner surfaces of the ends of the insulating mounts 5 and 6 kept in contact with the side edges of the flanges 3b and 3c of the bobbin 3 respectively, the protrusions 5b and 6b of the tongues 5c and 6c are fitted into engagement with the holes 4d and 4e of the horizontal part 4b of the yoke 4 (FIG. 7). In the condition where the contact blocks B and C are mounted on the electromagnet block A as mentioned above (FIG. 7), the insulating mounts 5 and 6 of the contact blocks B and C are positioned as close to the electromagnetic coil 2 as possible in the space above the plane contaning the longitudinal axis of the coil 2, in such a manner that the terminals 7, 9, 11, 13 and 8, 10, 12, 14 protruded downward from the insulating mounts 5 and 6 respectively are arranged in spaced relation with the electromagnetic coil 2 and the bobbin flanges 3b, 3c. In other words, the terminals 7, 9, 11, 13 and 8, 10, 12, 14 are positioned in the space formed between the lower part of the insulating mounts 5, 6 and the electromagnetic coil 2 and the bobbin flanges 3b, 3c. The electromagnetic coil 2 is wound in circles in section, and the lower part of the bobbin flanges 3b and 3c are formed in semicircular (not shown) or inverted trapezoidal shape in conformity with the outline of the electromagnetic coil 2, thereby maximizing the above-mentioned space. Numeral 17 shows a relay armature bent in the shape of , which is supported on the end 4c of the horizontal part 4b of the yoke 4 at the corner portion thereof. In the assembling process, the corner portion of the relay armature 17 is fitted into the recess between the protrusions 4f, 4f formed at the corners of the end 4c, thereby preventing the relay armature 17 from being displaced laterally.

The method for preventing the lateral displacement of the relay armature 17 in the supported condition thereof is not necessarily limited to the one mentioned above. As an alternative, for instance, an inwardly-bent protrusion 17g is formed at the corner portion of the relay armature 17 as shown in FIG. 13, and a recess 4g adapted for mating the protrusion 17g is formed at the end 4c of the yoke 4.

The relay armature 7 is arranged in such a manner that the vertical portion 17a thereof is opposed to the core end 1b. The free end of the horizontal portion 17b of the relay armature 17 is fitted with an actuator 18. The respective ends 18a and 18b of the actuator 18 are situated below the movable contact members 15 and 16 of the contact blocks B and C, so that at the time of attraction of the vertical portion 17a to the core end 1b, the ends 18a and 18b of the actuator 18 press the movable contact members 15 and 16 upward simultaneously into contact with the normally-open contacts 13a and 14a respectively. When the electromagnet block A is de-energized, the relay armature 17 is of course restored to the original condition thereof by the restoration power of the movable contact members 15 and 16, so that the movable contact members 15 and 16 are brought into contact with the normally-closed contacts 11a and 12a at the same time. The actuator 18, as shown in FIGS. 10 and 11, has a section formed into the shape of , and a protrusion 18d is formed on the lower side of the upper portion 18c thereof. On the other hand, the free end part of the relay armature 17 has a hole 17c. The free end of the relay armature 17 is held between the upper and lower portions 18c and 18e of the actuator 18 with the protrusion 18d fittingly engaged with the hole 17c, thereby securing the actuator 18 to the relay armature 17. Numeral 19 shows a tension plate of a thin material bent in the form of , which is secured to the ends of the contact blocks B and C at the vertical portion 19a thereof. A protrusion 17d formed on the upper surface of the end portion of the horizontal portion of the relay armature 17 is fitted into a through hole 19c of the horizontal portion 19b of the tension plate 19, thus preventing the removal of the relay armature 17. The tension plate 19 has a vertical portion 19a with the central part thereof cut to form two outwardly elastic legs 19d, 19d. Also, engaging steps 19e, 19e are formed on the lower outer sides of the legs 19d, 19d, that is, recesses 19g, 19g are formed in the same sides. Vertical slots 5d and 6d are formed in the opposed inner sides of one end part of each of the insulating mounts 5 and 6 of the contact blocks B and C respectively. The vertical slots 5d and 6d have engaging steps 5e and 6e respectively at the lower part thereof, that is, protrusions 5g and 6g to be fitted into the recesses 19g. (FIG. 8) The side edges of the legs 19d, 19d of the tension plate 19 are fitted into the vertical slots 5d, 6d from the top thereof, so that the engaging steps 19e, 19e of the legs 19d, 19d are engaged with the engaging steps 5d, 6e of the vertical slots 5d, 6d by utilization of the elasticity of the legs 19d, 19d. The side ends of the vertical portion 19a of the tension plate 19 have bent parts 19f, 19f, which are also fitted into the vertical slots 5d, 6d, thus eliminating the loosened condition which otherwise might occur in the state where the side edges of the legs 19d, 19d are fitted into the vertical slots 5d, 6d.

As mentioned above, according to the present invention, the electromagnet block A, contact blocks B and C, and the relay armature 17 are coupled with each other to construct the electromagnet relay-contact assembly D having the functions of a relay as an integral block.

Next, the electromagnet relay-contact assembly D is contained in a space defined by the upper wall, side walls and bottom wall of the housing E, thus completing a miniature relay. The housing E includes a base portion 20 having a bottom wall and part of side walls, and a cover portion 21 having the remainder of the side walls and an upper wall which is covered over the base portions 20. Though the cover portion 21 may be opaque, it is preferable to make the cover portion 21 transparent so as to enable external inspection of the operating conditions of the inner relay contacts. Protrusions 5f and 6f are formed on the outer sides of the insulating members 5 and 6 of the contact blocks B and C and engaged with the recesses 20a, 20a formed in the opposed side surfaces of the base portion 20, thus fittingly mounting the assembly in the base portion 20. According to the present invention, the base portion 20 has steps 20b, 20b on the opposed inner sides thereof, on which the lower ends of the insulating member 5 and 6 rest respectively when the electromagnet contact-relay assembly D is placed in the housing E. An inverted trapezoidal space 20c is formed adjacent to and between the steps 20b, 20b for containing the lower halves of the flanges 3b, 3b of the bobbin 3 and the electromagnetic coil 2. In this way, the inside of the base portion 20 is formed to conform to the outline of the electromagnet relay-contact assembly D in such a manner as to eliminate any useless space other than the minimum required for containing the assembly D. The outside of the bottom wall of the base portion 20 is formed similarly to the steps 20b, 20b and the inverted trapezoidal space 20c inside of the base portion 20. In other words, it comprises first flat bottom surfaces 20d, 20d and an inverted trapezoidal expansion 20e connected with the first flat bottom surfaces 20d, 20 d. The bottom surface of the expansion 20e is called the second flat bottom surface 20f. Holes 20g and 20h for accomodating terminals are bored through the bottom wall at the inner steps 20b, 20b and the corresponding first flat bottom surfaces 20d, 20d of the base portion 20 respectively. When the electromagnet relay-contact assembly D is contained in the base portion 20, the electromagnet relay-contact assembly D is positioned along the inner contour of the base portion 20 with the result that the terminals 7, 9, 11, 13 and 8, 10, 12, 14 of the contact blocks B and C are protruded downward from the bottom surfaces 20d, 20d via the through holes 20g and 20h respectively.

It will be seen from the foregoing description that according to the present invention the terminals 7, 9, 11, 13 and 8, 10, 12, 14 are arranged in parallel to each other in the spaces 20i, 20i partially defined by the first flat bottom surfaces 20d, 20d and the expansion 20e, at the sides of the expansion 20e of the bottom wall of the base portion 20.

Further, in the base portion 20 according to the present invention, ribs 20j, 20j are formed along the periphery of the first flat bottom surfaces 20d, 20d, thereby forming longitudinal recesses 20k, 20k between the sides of the expansion 20e and the ribs 20j, 20j. By filling a resin material into the recesses 20k, 20k, the through holes 20g, 20h for accomodating the terminals are hermetically sealed.

FIGS. 14 and 15 show another embodiment of the present invention, in which a pair of electromagnet relay-contact assemblies D and D' are contained in a single base portion 201. In this case, two expansions 201a and 201b are formed correspondingly to the electromagnet relay-contact assemblies D and D' respectively, so that the terminals 7, 9, 11, 13 and 8, 10, 12, 14 of the electromagnet relay-contact assembly D and the terminals 7', 9', 11', 13' and 8', 10', 12', 14' are arranged in parallel to each other at the sides of the expansions 201a and 201b respectively.

According to the related regulations on standards, adjacent terminal groups, for instance, the terminal group of the electromagnet relay-contact assembly D including 8, 10, 12 14 and the terminals 5 group of the electromagnet relay-contact assembly D' including 7', 9', 11', 13' are required to be spaced by a predetermined distance from each other. As a result, a space S is provided between the contact block C of the electromagnet relay-contact assembly D and the contact block B' of the electromagnet relay-contact assembly D' as shown in FIG. 15. This space S may be used to arrange indication means such as illumination means including light-emitting diodes (not shown) for indicating the operating conditions of the electromagnet relay-contact assemblies D and D'. In this case, the cover portion of the housing E is of course made transparent.

The present invention may be embodied with equal effect in an arrangement in which three or more electromagnet relay-contact assemblies are contained in a single space.

The base portion according to the present invention is alternatively constructed as shown in FIG. 16. In this embodiment, the base portion 202 has only the bottom wall of the housing, for containing the part of the electromagnet relay-contact assembly D lower than the lower end surfaces of the insulating mounts 5 and 6, while the remaining part is contained in the cover portion 211 including the side and upper walls. The lower ends of the insulating mounts 5 and 6 of the electromagnet relay-contact assembly D are rested on the side rims 202a, 202a of the base portion 202. The inside surface of the cover portion 211 is provided with engaging recesses 211a, 211a, with which the protrusions 5f, 6f on the sides of the insulating mounts 5 and 6 are engaged fixedly.

Instead of provision of the ribs 20j (FIG. 7) in the preceding embodiments, whether in the case where only one electromagnet relay-contact assembly is provided in the housing E or in the case where two or more than two electromagnet relay-contact assemblies are accomodated in the housing E, the longitudinal side wall of the cover portion of the housing E may be extended downwardly so as to form recesses 20k', 20k' in cooperation with the side wall of the expansion 20e, as shown in FIG. 15, in which a resin material may be filled to seal the relay in the same manner as already described with respect to the recesses 20k, 20k.

As another alternative not shown, each of the longitudinal ends of the base portion 20 forming the housing E has an opening which is closed by the side walls of the cover portion 21.

Further, the expansion 20e formed in the bottom wall of the base portion 20 may be rectangular or semicircular instead of inverted trapezoidal in shape.

Although the embodiment mentioned above is of what is called double-pole type in which the electromagnet relay-contact assembly includes two contact blocks B and C, it may alternatively be constructed as a single pole type in which the electromagnet relay-contact assembly includes one of the contact blocks B and C and the other block is replaced by a dummy block having only coil terminals. As another alternative, the common terminals 9, 10, the normally-closed contact terminals 11, 12, and the normally open contact terminals 13, 14 may be connected to each other respectively at the upper end bent portions thereof as shown in FIG. 17, thus constituting a single pole type of assembly with double current capacity.

The miniature relay according to the invention constructed as mentioned above may also include a socket 22 having a central aperture 22a and plug-receiving terminals 23 and 24 parallelly provided on both sides opposedly to each other as shown in FIG. 18. In the case where the assembly is mounted on this socket 22 as shown in FIG. 19, the expansion 20e is fitted into the aperture 22a and the terminals 7, 9, 11, 13 and 8, 10, 12, 14 are inserted into the plug-receiving terminals 23 and 24 respectively. As a result, the first flat bottom surfaces 20d, 20d of the base portion 20 are mounted on the upper surface of the socket 22. In other words, by rendering the height t of the socket 22 substantially equal to the vertical distance between the first bottom surfaces 20d, 20d and the second bottom surface 20f, it is possible to render the height T of the relay from the second bottom surface 20f to the upper surface thereof equal to the mounting height conveniently without being affected in mounting height by the socket 22.

Numeral 30 shows elastic arms rising from the upper surface of the socket 22 and having a horizontal protrusion. The relay is mounted in the socket 22 against the elasticity of the arms 30, and after it is mounted in the socket, the protrusions 30a function as a locking means.

FIG. 20 shows another method of mounting the relay according to the present invention directly on the printed-circuit board P. In this case, the printed-circuit board P is formed with an aperture P1 adapted to be fitted with the expansion 20e, and a plurality of terminal-receiving holes along the opposed two sides of the apertures P1. The expansion 20e is fitted into the aperture P1 so that the first flat bottom surfaces 20d, 20d are rested on the upper surface of the board P at the sides of the aperture P1. Thus the mounting height from the upper surface of the printed-circuit board P may be only about one half that of the relay proper.

The relay according to the present invention may be mounted with the second bottom 20f rested on the printed-circuit board P as shown in FIG. 21, in which case, the advantage in respect of the mounting height is not attained like in the conventional relay-mounting methods. In this mounting method, however, the first flat bottom surfaces 20d, 20d from which the terminals are protruded are positioned over the printed-circuit board P in spaced relation therewith, resulting in the advantage of eliminating the effect of the penetration of solder flux between the relay bottom and the printed-circuit board or soldering heat on the internal parts which otherwise might occur in soldering the terminals. In using this method of mounting, the terminals are of course extended further downwardly of the second flat bottom surface 20f.

In asembly work of the relay according to the present invention, the electromagnet block A, the contact blocks B and C are prepared beforehand by the part-manufacturing processes therefor. In the final process, the electromagnet block A, the contact blocks B, C and the relay armature 17 are coupled with each other by simple pressure fitting, thereby completing the electromagnet relay-contact assembly, which is then contained in the housing E. In this way, the assembly work is very simple on the one hand, and blocks are used commonly to relays of different ratings, thus leading to the advantage in stock control on the other hand. Also, the construction according to the present invention totally eliminates wasteful space, thus greatly contributing to the reduced size of the relay. Still another advantage of the present invention lies in that regardless of whether the relay proper is mounted on the printed-circuit board directly or through a socket, the mounting height is greatly reduced. Especially when using the socket, the height thereof is capable of being ignored entirely to a very great practical advantage.

Although the above-mentioend embodiments are explained with reference to a relay with contacts, the essential parts of the present invention may of course be applied with equal effect to a reed relay and a contactless relay.