COMPACT DESIGN RELAY

Abstract: In a compact design relay, in which gaps between a base member (2) and a case member (3) covering the base member and between the base member (2) and terminal pins (1) mounted on the base member are sealed by filing the gaps with an adhesive (4) which is thermally hardened thereafter, a small air vent hole (5) is formed in part of the case member (3) and/or base member (2) free from the adhesive (4) and is sealed with a further adhesive (8) after the thermal hardening treatment of the first-mentioned adhesive (4).

Description: COMPACT DESIGN RELAY This invention relates to miniature or compact design relays and, more particulaly, to compact design relays having a sealed construction. Usually, a compact design relay of this type is manufactured by covering a base member provided with necessary terminal pins with a case open at the bottom and a resin adhesive which is applied to portions of the base in engagement with the open end of the cover and those receiving the terminal pins and then thermally hardened. With this construction, however, at the time of the thermal treatment of the resin adhesive the air pressure in the interior of the case is so increased that the inside air leaks to the outside through the adhesive before the adhesive is completely hardened, resultinq in such disadvantages that very small air passages may be formed in the adhesive material and that gases produced from the adhesive during the thermal treatment thereof is filled in the interior of the case. An object of the invention is to remove the drawbacks discussed above. To achieve the above object, according to the invention there is provided a compact design relay, in which a gap between a base member provided with terminal pins and a case coverinq the base is sealed by fillinq the qap with an adhesive and thermally hardening the adhesive, and in which a vent hole is formed in a portion of the case and/or the base free from the adhesive and is sealed with a further adhesive after the thermal treatment of the first-mentioned adhesive. Fig. 1 is a sectional view showinq an example of the conventional compact design relay. Fiq. 2 is a perspective view showing an embodiment of the invention. Fiq. 3 is a sectional view of the embodiment of Fiq. 2. Fiq. 4 is a perspective view showing another embodiment of the invention. Fig. 5 is a sectional view of the embodiment of Fig. 4. Fig. 6 is a perspective view showing a further embodiment of the invention. Fig. 7 is a sectional view of the embodiment of Fig. 6. Fig. 8 is a perspective view showing a still further embodiment of the invention. Fig. 9 is a sectional view of the embodiment of Fig. 8. For the better understanding of the invention, an example of the conventional compact desiqn relay, shown in Fiq. 1, will first be described. This compact design relay is manufactured by covering a base member 2 provided with terminal pins 1 with a case 3 open at the bottom and sealinq the assembly with a resin adhesive 4 which is applied to portions of the base in enqagement with the open end of the cover and those receivinq the terminal pins and then thermally hardened. In this case, the adhesive 4 may extend over the while area of the lower end opening of the case 4 and this construction has the drawbacks as discussed previously. Fiqs. 2 and 3 show a preferred embodiment in which the invention is applied to such a compact desiqn relay as disclosed in the United States Patent No. 4,227,162 assiqned to the same assiqnee of this invention. In this preferred embodiment a base 2 has a portion 6 which expands outwardly downwardly and extends alonq the lonqitudinal center axis of the base 2. A small hol 5 is formed in a recess 7 provided at a qiven portion of the expanded base portion 6 and a plurality of terminal pins 1 are arranqed parallelly alonq the opposite sides of the expanded portion 6. In this embodiment the inflated air due to the inner pressure produced when thermally hardeninq the adhesive 4 filinq the qap between the case 3 and base 2 and also gases produced from the adhesive at this time may be exhausted throuqh the hole 5 to the outside, so that there is no possibility of the formation of small air passaqes in the hardened adhesive and also a cloud of qases produced from the adhesive. After the hardeninq of the adhesive 4, the small hole 5 is sealed with a small quantity of adhesive 8 in the last step. At this time, only a very small quantity of adhesive 8 is required for sealing the small hole 5, so that there is no possibility of increasinq the internal pressure, and the reliability of sealinq can be increased. With this construction with the base 2 having such an expanded portion 6, the molding can be provided over a reduced area, and the quantity of the necessary resin can be reduced. Further, when the relay is mounted on a printed -circuit board P for use, improved ventilation can be obtained since a gap is formed between the portion of the relay base at which the terminal pins are mounted the surface portion of the printed-circuit board. Further, since the expanded portion 6 is provided on the underside of the base, the small hole 5 for sealing can be provided in the expanded portion 6 without sacrifice in appearance in use at all. Further, if the interior of the expanded portion 6 of the base 2 is utilized for accommodating a relay coil section, the height of the relay from the printed-circuit board in the mounted state can be reduced to obtain a more compact construction as a whole. While in the illustrated embodiment a recess 7 is formed so that adhesive may spread over the portion of the recess 7 around the small hole 5, it is only necessary for the adhesive to close the small hole 5 which is very small, and it is not necessary to fill the entire recess 7 with the adhesive. Further, while in the above embodiment the small hole 5 is provided at the center of the expanded portion 6 of the base 2 in the longitudinal direction thereof, this position of the small hole 5 is by no means limitative. Further, the recess for receiving the adhesive is not always necessary. For example, as shown in Figs. 4 and 5, a ridge 9 provided on the expanded portion 6 to surround the small hall 5 may prevent the adhesive 8 from spreadinq widely over the surface of the expanded portion 6 in case an excessive quantity of adhesive is applied to the hole 5. In this case, however, since only the lower surface of the ridge 9 comes into abutment contact with the upper surface of a printed-circuit board when the relay is mounted on the board in use, it is preferable to povided another ridge 10 which is arranged substantially symmetrically with respect to the ridqe 9 in order to assure the steady mountinq of the relay. Further, while in the above embodiment the base 2 is provided with the expanded portion 6, it is also possible to make the lower surface of the base 2 flat, as shown in Fiqs. 6 and 7, with qrooves 11 formed in the terminal pin mountinq portions of the base 2 so that the terminal pins 1 are mounted in these qrooves 11 and the qrooves 11 are filled with the adhesive 4, provided that there is no problem in ventilation of the underside of the relay. In this case, the small hole 5 may be provided in any suitable portion other than the qrooves. The ridge 9 surrounding the small hole 5 and the ridge 10 for the purpose of steadiness may be provided also in this embodiment in the same manner as in the embodiment of Figs. 4 and 5. However, such a sinqle bar-like ridge 12 may be substituted for the surroundinq ridqe 10, as shown in Fiq. 6. Further, in the case there is no problem with respect to the heat dissipation or the whole heiqht of the relay when it is mounted on a board, such an embodiment as shown in Fiqs. 8 and 9 may be utilized. In this embodiment, no grooves are not provided in the base 2 and the adhesive 4 is applied to whole the bottom surfaces of the base 2 except for the areas surrounded by the ridge 9 surrounding the small hole 5 and the ridqe 10 for the purpose of steadiness. In this embodiment, the adhesive is unavoidably increased in its quantity. However, the increase in the quantity of adhesive may be considerably reduced by wideninq the areas surrounded by the ridqes 9 and 10. Further, from the standpoint of the function of the small hole 5 alone, the small hole 5 may be provided in the case 3 or to penetrate both the case 3 and base 2. From the standpoint of appearance, howevere, it is of course better to provide the small hole 5 in the underside of the base 2.

Claims: WHAT IS CLAIMED IS: 1. A compact design relay comprising: a base member (2) provided with a relay mechanism and terminal pins (1) connected to said relay mechanism; a case member (3) covering said base member; a first adhesive (4) applied to gaps formed between said base member and said case member and between said base member and said terminal pins and thermally hardened so as to air-trigh±ly seal said gaps; a small air vent hole (5) formed in at least one of a part of said case member and a part of said base member free from said first adhesive; and a second adhesive (8) applied to said small air vent hole after the hardening treatment of said first adhesive. 2. A compact design relay according to claim 1, wherein said base member (2) has a portion (6) which expands outsardly downwardly and which extends along a longitudinal center axis of said base member said terminal pins (1) being mounted at portions of said base member along the opposite sides of said expanded portion so that a gap may be provided between the terminal pin mounting portions of said base member and a relay mounting member (P) when the relay is mounted for use on said relay mounting member. 3. A compact design relay according to claim 2, wherein said small air vent hole (5) is formed in a portion of said expanded base portion (6). 4. A compact design relay according to claim 1, 2 or 3, wherein said base member (2) is provided with grooves (11) communicating with said gaps, and said grooves are filled with said first adhesive(4). 5. A compact design relay according to claim 4, wherein siad base member (2) is provided with a recessed portion (7) and said small air vent hole (5) is formed within said recessed portion. 6. A compact design relay according to claim 4, wherein said base member (2) is provided with a first ridge (9) surrounding said small air vent hole (5). 7. A compact design relay according to claim 6, wherein said base member (2) is provided with a second ridge (10, 12) for stabilizing the mounting state of said relay on a relay mounting member (P) in use, in cooperation with said first ridge (9).

Inventors: TEIZO, FUJITA
Applicants: IZUMI DENKI CORPORATION
Application year: 1981
Main classification: H01H50
IPC codes: H01H45, H01H50, G06Q50