Abstract: A glow plug includes a housing having an axial hold and provided with a screw portion, and a heater member inserted into the axial hole. The housing includes a front-end-side body portion extending to the front end side from a front end of the screw portion, and a gasket portion lying adjacent to a front end side of the front-end-side body portion and bent at a bent portion provided at a rear end thereof so that at least a rear end portion thereof extends in a direction intersecting a direction of an axis. The gasket portion includes a pressure contact portion in which a surface thereof located at an outer circumferential side is brought into pressure contact with a seat surface of an internal combustion engine when the screw portion is screwed into a mounting hole in the internal combustion engine.

Abstract: A glow plug includes a cylindrical housing having an axial hole which extends in the direction of an axis and provided with, on an outer circumferential surface thereof, a screw portion for being screwed into a mounting hole of an internal combustion engine, and a heater member inserted into the axial hole in a state where at least front end portion thereof projects from a front end of the housing. The housing includes a tool engagement portion which is provided at a rear end side than the screw portion and to which a tool is engaged when the being mounted to the internal combustion engine. An inner circumference of the tool engagement portion has a shape which follows an outer circumferential shape of the tool engagement portion.

Abstract: A glow plug (1) has a housing (2) and a heater (3). The housing (2) includes a thread portion (5), a tool engagement portion (6), a press contact portion (7) brought into press contact with a plug seat surface of an engine upon screwing the thread portion (5) into a mounting hole of the engine, a front body portion (9) located between the press contact portion (7) and the thread portion (5) and a rear body portion (8) located between the tool engagement portion (6) and the thread portion (5). At least one of the front body portion (9) and the rear body portion (8) has a thickness smaller than or equal to a predetermined value and includes a plurality of reinforcing parts (9A, 8A) provided intermittently in a circumferential direction of the housing (2) in the form of protrusions or recesses extending in the direction of an axis CL1.

Abstract: A glow plug includes a cylindrical housing having an axial hole which extends in the direction of an axis and provided with, on an outer circumferential surface thereof, a screw portion for being screwed into a mounting hole of an internal combustion engine, and a heater member inserted into the axial hole in a state where at least front end portion thereof projects from a front end of the housing. The housing includes a tool engagement portion which is provided at a rear end side than the screw portion and to which a tool is engaged when the being mounted to the internal combustion engine. An inner circumference of the tool engagement portion has a shape which follows an outer circumferential shape of the tool engagement portion.

Abstract: A glow plug includes a housing having an axial hold and provided with a screw portion, and a heater member inserted into the axial hole. The housing includes a front-end-side body portion extending to the front end side from a front end of the screw portion, and a gasket portion lying adjacent to a front end side of the front-end-side body portion and bent at a bent portion provided at a rear end thereof so that at least a rear end portion thereof extends in a direction intersecting a direction of an axis. The gasket portion includes a pressure contact portion in which a surface thereof located at an outer circumferential side is brought into pressure contact with a seat surface of an internal combustion engine when the screw portion is screwed into a mounting hole in the internal combustion engine.

Abstract: A glow plug includes a cylindrical housing having an axial hole and provided with a screw portion, and a heater member which is inserted into the axial hole in a state where at least a front end portion thereof projects from a front end of the housing. The housing includes a pressure contact portion brought into pressure contact with a seat surface of an internal combustion engine when the screw portion is screwed into a mounting hole of the internal combustion engine, and a cylindrical front-end-side body portion provided between the pressure contact portion and the screw portion. The front-end-side body portion includes a holding portion which holds the heater member directly or indirectly at an inner circumference thereof, and the holding portion has a smallest outer diameter in the front-end-side body portion.

Abstract: A glow plug (1) has a housing (2) and a heater (3). The housing (2) includes a thread portion (5), a tool engagement portion (6), a press contact portion (7) brought into press contact with a plug seat surface of an engine upon screwing the thread portion (5) into a mounting hole of the engine, a front body portion (9) located between the press contact portion (7) and the thread portion (5) and a rear body portion (8) located between the tool engagement portion (6) and the thread portion (5). At least one of the front body portion (9) and the rear body portion (8) has a thickness smaller than or equal to a predetermined value and includes a plurality of reinforcing parts (9A, 8A) provided intermittently in a circumferential direction of the housing (2) in the form of protrusions or recesses extending in the direction of an axis CL1.

Abstract: A sheath heater for a glow plug comprises a sheath tube having a closed front end portion, and an open rear end portion. An insulating powder is charged into a gap between the sheath tube and a heat-generating resistor disposed within the sheath tube. A seal member includes an expanded portion extending radially outwardly from an outer circumference of the seal member, and a non-expanded portion of a smaller outside diameter than the expanded portion and formed on the outer circumference of the seal member at least at a leading end of the seal member. The seal member is fitted into the open rear end portion of the sheath tube such that the leading end enters the sheath tube first. The sheath tube is deformed radially inwardly around the seal member for sealing the heat-generating resistor and the insulating powder contained in the sheath tube.

Abstract: A first center pole (8) is prepared in which an inserting portion (8c) capable of being inserted into an insertion receiving portion (5b) of a heating coil (5) has been formed at its distal end. In a first step, the inserting portion 8c of the first center pole (8) is inserted into the insertion receiving portion (5b) of the heating coil (5) to form an overlapping portion (10a), thereby obtaining a first glow plug intermediate body (10). Then, in a second step, as a current is applied across electrodes (81) and (82) while sandwiching the overlapping portion (10a) by the electrodes (81) and (82), the inserting portion (8c) of the first center pole (8) and the insertion receiving portion (5b) of the heating coil (5) are welded together so as to form a weld portion (10b).

Abstract: A sheath heater for a glow plug comprises a sheath tube having a closed front end portion, and an open rear end portion. An insulating powder is charged into a gap between the sheath tube and a heat-generating resistor disposed within the sheath tube. A seal member includes an expanded portion extending radially outwardly from an outer circumference of the seal member, and a non-expanded portion of a smaller outside diameter than the expanded portion and formed on the outer circumference of the seal member at least at a leading end of the seal member. The seal member is fitted into the open rear end portion of the sheath tube such that the leading end enters the sheath tube first. The sheath tube is deformed radially inwardly around the seal member for sealing the heat-generating resistor and the insulating powder contained in the sheath tube.