Abstract: An object of the present invention is to provide an ignition coil for use in an internal combustion engine, offering improved water drainage performance, while achieving high waterproof performance with controlled entry of water in a plug hole. A high-voltage generating section 3 that generates a high voltage is housed inside a coil case 4. A plug hole seal 5 closes an opening in a plug hole 2 in which an ignition plug 21 is mounted. The ignition coil further includes a space portion 6 placed on an outer side portion of the high-voltage generating section 3 and an air path 9 for venting air between the space portion 6 and the plug hole 2. The space portion 9 has an open lower surface (an entirely open surface facilitates demolding).

Abstract: An auxiliary core portion and a main core portion, including a magnet if the magnet is attached, are covered by a resin film or an elastomer film and fixed as a single assembly. In this state, a coil is attached to the assembly and a side core portion is assembled to the assembly. The auxiliary core portion and the main core portion, including the magnet if it is attached, can be supplied, as the single assembly, to an automated assembly line for ignition coils. It is not necessary to position such components on the assembly line. Thus, the workability of the automated assembly can be enhanced.

Abstract: An object of the present invention is to provide an ignition coil for use in an internal combustion engine, offering improved water drainage performance, while achieving high waterproof performance with controlled entry of water in a plug hole. A high-voltage generating section 3 that generates a high voltage is housed inside a coil case 4. A plug hole seal 5 closes an opening in a plug hole 2 in which an ignition plug 21 is mounted. The ignition coil further includes a space portion 6 placed on an outer side portion of the high-voltage generating section 3 and an air path 9 for venting air between the space portion 6 and the plug hole 2. The space portion 9 has an open lower surface (an entirely open surface facilitates demolding).

Abstract: An auxiliary core portion and a main core portion, including a magnet if the magnet is attached, are covered by a resin film or an elastomer film and fixed as a single assembly. In this state, a coil is attached to the assembly and a side core portion is assembled to the assembly. The auxiliary core portion and the main core portion, including the magnet if it is attached, can be supplied, as the single assembly, to an automated assembly line for ignition coils. It is not necessary to position such components on the assembly line. Thus, the workability of the automated assembly can be enhanced.

Abstract: An internal combustion engine ignition coil device has an annular seal rubber at its lower side coil. An annular projection is provided on a part of the seal rubber and is pressed against the inner diameter surface of a plug hole. An air path is formed in part of a coil case by mounting the seal rubber into a groove, enabling inside and outside portions of the plug hole to communicate. A gas-permeable thin film resin member is bonded to an inlet of the air path.

Abstract: An internal combustion engine ignition coil device has an annular seal rubber at its lower side coil. An annular projection is provided on a part of the seal rubber and is pressed against the inner diameter surface of a plug hole. An air path is formed in part of a coil case by mounting the seal rubber into a groove, enabling inside and outside portions of the plug hole to communicate. A gas-permeable thin film resin member is bonded to an inlet of the air path.

Abstract: An internal combustion engine ignition coil device has an annular seal rubber at its lower side coil. An annular projection is provided on a part of the seal rubber and is pressed against the inner diameter surface of a plug hole. An air path is formed in part of a coil case by mounting the seal rubber into a groove, enabling inside and outside portions of the plug hole to communicate. A gas-permeable thin film resin member is bonded to an inlet of the air path.

Abstract: An internal combustion engine ignition coil device has an annular seal rubber at its lower side coil. An annular projection is provided on a part of the seal rubber and is pressed against the inner diameter surface of a plug hole. An air path is formed in part of a coil case by mounting the seal rubber into a groove, enabling inside and outside portions of the plug hole to communicate. A gas-permeable thin film resin member is bonded to an inlet of the air path.

Abstract: An internal combustion engine ignition coil device has an annular seal rubber at its lower side coil. An annular projection is provided on a part of the seal rubber and is pressed against the inner diameter surface of a plug hole. An air path is formed in part of a coil case by mounting the seal rubber into a groove, enabling inside and outside portions of the plug hole to communicate. A gas-permeable thin film resin member is bonded to an inlet of the air path.

Abstract: An ignition coil device for an internal combustion engine, which has a superior waterproof property and can be reduced in size and easily produced. An annular seal rubber (2) is mounted to the lower side of an ignition coil device (1). An annular projection (2a) is provided on a part of the seal rubber and is pressed against the inner diameter surface of a plug hole. A substantially L-shaped groove for forming an air path (4) is formed in a part of a coil case (1a). The air path (4) is formed by mounting the seal rubber (2) into the groove, enabling the inside and the outside of the plug hole to communicate with each other. A thin film resin member (3) with a porous structure being permeable to gas but not to liquid is fixedly bonded to an inlet (4a) of the air path (4) to prevent water from entering the plug hole. Those features realize the ignition coil device for the internal combustion engine, which has a superior waterproof property and can be reduced in size and easily produced.

Abstract: High purity synthetic quartz glass particles are derived from alkali metal silicate and have a total amount of metal impurities content of at least 1 &mgr;g/g and, in particular, have oxygen-deficient defects. The high-purity synthetic quartz glass particles having high viscosity similar to natural quartz and high-purity similar to known synthetic quartz can be provided at a low cost.

Abstract: An expansion joint for use in constructing concrete material structures of the present invention has a plurality of sandwich type composite plates each comprising a sheet-like elastic body sandwiched by a pair of hard plates with a rib at both surfaces thereof are connected with each other through a water-swelling rubber.