Abstract: To provide a method for producing a ceramic porous material which has a high strength, though it has a high porosity, and which is excellent in permeability without dust generation. In a ceramic porous material having a three-dimensional mesh-like skeleton structure with a large number of substantially spherical adjacent cells communicating with each other via communication holes, the crystal particle size at the rim of each communication hole in the skeleton structure is provided substantially equal to the crystal particle size in the other parts.

Abstract: A stick-type ignition coil have a central core, a cylindrical member, primary spool, primary coil, secondary spool, secondary coil, outer core and a resin insulator. The two longitudinal end corners and faces of the core are covered by respective buffer members. The inner circumferential corners of the outer core is supported by ring members. Some of the members disposed radially inside and other members disposed radially outside of the inside members are held slidably to each other in the ignition coil. The spools are made of resin containing a rubber in excess of 5 weight percent and reinforcing materials. The resin insulator contains a flexible material.

Abstract: A stick-type ignition coil have a central core, a cylindrical member, primary spool, primary coil, secondary spool, secondary coil, outer core and a resin insulator. The two longitudinal end corners and faces of the core are covered by respective buffer members. The inner circumferential corners of the outer core is supported by ring members. Some of the members disposed radially inside and other members disposed radially outside of the inside members are held slidably to each other in the ignition coil. The spools are made of resin containing a rubber in excess of 5 weight percent and reinforcing materials. The resin insulator contains a flexible material.

Abstract: An ignition coil assembly includes a base member formed with collars having corrugated faces at the bottom ends thereof. Corresponding bosses are formed on the engine head cover, which also have corrugated faces conforming to those of the collars. When the base member is mounted on the engine, the ribs of one of the corrugated faces are fitted in the ridges of a corresponding corrugated face. When removing the ignition coil assembly from the engine, the relative positions of these corrugated faces are changed so that the ribs of one of the corrugated faces ride up onto the ribs of the other one, whereby the base member is lifted up.

Abstract: The ceramic member of this invention is formed on the surfaces of crystal grains with a plurality of protrusions having smaller diameter than that of the crystal grain, said crystal grain composing at least the surface or its vicinity of a dense ceramic base material of purity being 95 wt % or higher. Such ceramic members may be produced by performing the surface of a dense ceramic base material with a corrosion treatment in an acid etchant, the dense ceramic base material having purity of 95 wt % or higher and exceeding 90% of a theoretical density, whereby ceramic grains existing on the surface or its vicinity of the base material are formed on the surface thereof with a plurality of protrusions.

Abstract: An ignition coil (1) having a case (2), a core (22) installed in the case, a primary spool (25) disposed substantially coaxially around an outer circumference of the core within the case, a primary coil (26) comprising a wire wound around the primary spool, a secondary spool (23) disposed substantially coaxially around the outer circumference of the core within the case, a secondary coil (24) comprising a wire wound around the secondary spool and a resin insulating material (5) filled within the case, the ignition coil being characterized in that the spool of the primary and the secondary spools which is disposed between the secondary coil and the core and/or which is disposed between the secondary coil and the primary coil comprises a base resin having an adhesive strength to the resin insulating material which is less than that provided by polybutylene terephthalate and an insulation breakdown voltage which exceeds that provided by polyphenylene sulfide.

Abstract: Plural ignition coils are inserted into corresponding plug holes. Each coil-head of the ignition coil is received by a holder. The coil-head is pressed by a base plate toward the engine. The holder has hooking claws. The base plate has hooking slots to movably engage with the hooking claws, so that relative position between the ignition coils and the plug holes can be adjusted. In case one ignition coil fails, the disabled ignition coil can be replaced individually. A first connector is formed on the coil-head, and a second connector is formed on the holder. The second connector is connected with the first connector when the holder is engaged with the ignition coil at one time. Thus, assembly work process can be reduced.

Abstract: In a stick coil, there is disclosed an ignition coil for an internal combustion engine which can prevent a crack (a collar leak) from being generated due to a thermal stress. In this ignition coil, the structure is made such that a size (L) of a portion which is in parallel to an axial direction of a primary spool (121) in a projection portion (121b) is larger than a size (T) of a portion which is in parallel to an orthogonal direction to the axial direction of the primary spool (121). Accordingly, a frontal projected area of the projection portion (121b) as seen from a flowing direction of a resin becomes small, a resin flow is hard to get out of order at a time when the resin flows through a portion corresponding to the projection portion (121b) at the forming time, and a convoluted void and a weld are hard to be generated.

Abstract: An ignition coil device is mounted in a plug hole member forming a plug hole with forming internal space with the plug hole member. The ignition coil device includes a primary spool, a primary coil wire that is wound around an outer surface of the primary spool. At least a given portion of the outer surface of the primary spool is formed of crystalline resin. Here, the given portion fluidly communicates with the internal space of the plug hole.

Abstract: An ignition coil device has a secondary spool, a secondary coil wound around the secondary spool, an insulating resin material that is filled into spaces between the secondary windings, a primary spool, a primary coil wound around the primary spool, a connector that is arranged on one end side in an axial direction of these parts and has a connector terminal electrically connected to the primary coil and the secondary coil, and a resin insulting material for connector that is filled into the connector. The base material of the coil insulating resin material is the same as or different from the base material of the connector insulating resin material.

Abstract: An ignition coil device has a secondary spool, a secondary coil wound around the secondary spool, a coil insulating resin material that is impregnated into and cured in spaces between the windings of the secondary coil, a primary spool arranged on the secondary coil, a primary coil wound around the primary spool, and a high voltage tower that is arranged on one end side in the axial direction of these parts and is mounted with an ignition plug. At least one of two parts of the primary spool and the high voltage tower and the coil insulating resin material are integrally molded out of the same resin.

Abstract: In a stick coil, there is disclosed an ignition coil for an internal combustion engine which can prevent a crack (a collar leak) from being generated due to a thermal stress. In this ignition coil, the structure is made such that a size (L) of a portion which is in parallel to an axial direction of a primary spool (121) in a projection portion (121b) is larger than a size (T) of a portion which is in parallel to an orthogonal direction to the axial direction of the primary spool (121). Accordingly, a frontal projected area of the projection portion (121b) as seen from a flowing direction of a resin becomes small, a resin flow is hard to get out of order at a time when the resin flows through a portion corresponding to the projection portion (121b) at the forming time, and a convoluted void and a weld are hard to be generated.

Abstract: Plural ignition coils are inserted into corresponding plug holes. Each coil-head of the ignition coil is received by a holder. The coil-head is pressed by a base plate toward the engine. The holder has hooking claws. The base plate has hooking slots to movably engage with the hooking claws, so that relative position between the ignition coils and the plug holes can be adjusted. In case one ignition coil fails, the disabled ignition coil can be replaced individually. A first connector is formed on the coil-head, and a second connector is formed on the holder. The second connector is connected with the first connector when the holder is engaged with the ignition coil at one time. Thus, assembly work process can be reduced.

Abstract: An ignition coil assembly includes a base member formed with collars having corrugated faces at the bottom ends thereof. Corresponding bosses are formed on the engine head cover, which also have corrugated faces conforming to those of the collars. When the base member is mounted on the engine, the ribs of one of the corrugated faces are fitted in the ridges of a corresponding corrugated face. When removing the ignition coil assembly from the engine, the relative positions of these corrugated faces are changed so that the ribs of one of the corrugated faces ride up onto the ribs of the other one, whereby the base member is lifted up.

Abstract: An ignition coil (1) having a case (2), a core (22) installed in the case, a primary spool (25) disposed substantially coaxially around an outer circumference of the core within the case, a primary coil (26) comprising a wire wound around the primary spool, a secondary spool (23) disposed substantially coaxially around the outer circumference of the core within the case, a secondary coil (24) comprising a wire wound around the secondary spool and a resin insulating material (5) filled within the case, the ignition coil being characterized in that the spool of the primary and the secondary spools which is disposed between the secondary coil and the core and/or which is disposed between the secondary coil and the primary coil comprises a base resin having an adhesive strength to the resin insulating material which is less than that provided by polybutylene terephthalate and an insulation breakdown voltage which exceeds that provided by polyphenylene sulfide.

Abstract: In order to prevent a crack of plastic parts caused by a shrinkage force of a resin filler filled in an ignition coil casing, a cylindrical coil casing houses a primary coil and a secondary coil concentrically, and the resin filler such as epoxy resin is filled in the coil casing to insulate between the parts in the coil casing and to fix the parts. A ring-shaped partition member is provided at the upper portion in the coil casing to separate the resin filler locating above the primary coil and the secondary coil inside and outside. The partition member is made of a resin whose adhesive strength against the resin filler is weak, such as polypropylene (PP). The partition member reduces the shrinkage force between the outside resin filler and the inside resin filler, and prevents a crack of plastic parts, such as the secondary spool.

Abstract: To provide a method for producing a ceramic porous material which has a high strength, though it has a high porosity, and which is excellent in permeability without dust generation. In a ceramic porous material having a three-dimensional mesh-like skeleton structure with a large number of substantially spherical adjacent cells communicating with each other via communication holes, the crystal particle size at the rim of each communication hole in the skeleton structure is provided substantially equal to the crystal particle size in the other parts.

Abstract: The ceramic member of this invention is formed on the surfaces of crystal grains with a plurality of protrusions having smaller diameter than that of the crystal grain, said crystal grain composing at least the surface or its vicinity of a dense ceramic base material of purity being 95 wt % or higher. Such ceramic members may be produced by performing the surface of a dense ceramic base material with a corrosion treatment in an acid etchant, the dense ceramic base material having purity of 95 wt % or higher and exceeding 90% of a theoretical density, whereby ceramic grains existing on the surface or its vicinity of the base material are formed on the surface thereof with a plurality of protrusions.

Abstract: In a stick coil, there is disclosed an ignition coil for an internal combustion engine which can prevent a crack (a collar leak) from being generated due to a thermal stress. In this ignition coil, the structure is made such that a size (L) of a portion which is in parallel to an axial direction of a primary spool (121) in a projection portion (121b) is larger than a size (T) of a portion which is in parallel to an orthogonal direction to the axial direction of the primary spool (121). Accordingly, a frontal projected area of the projection portion (121b) as seen from a flowing direction of a resin becomes small, a resin flow is hard to get out of order at a time when the resin flows through a portion corresponding to the projection portion (121b) at the forming time, and a convoluted void and a weld are hard to be generated.

Abstract: In order to prevent a crack of plastic parts caused by a shrinkage force of a resin filler filled in an ignition coil casing, a cylindrical coil casing houses a primary coil and a secondary coil concentrically, and the resin filler such as epoxy resin is filled in the coil casing to insulate between the parts in the coil casing and to fix the parts. A ring-shaped partition member is provided at the upper portion in the coil casing to separate the resin filler locating above the primary coil and the secondary coil inside and outside. The partition member is made of a resin whose adhesive strength against the resin filler is weak, such as polypropylene (PP). The partition member reduces the shrinkage force between the outside resin filler and the inside resin filler, and prevents a crack of plastic parts, such as the secondary spool.