| 摘要 |
[Objective] To provide a glow plug having a combustion pressure sensor whose accuracy in sensing combustion pressure is improved through mitigation of an action that a tubular seal member (holding member) disposed between the outer circumferential surface of a heater and the inner circumferential surface of a portion of a housing located toward the forward end of the housing presses the heater forward as a result of its instantaneous thermal expansion which arises instantaneously, since it is thin-walled and thus instantaneously assumes high temperature. [Means for Solution] A seal member 60 has a dual-tube structure consisting of an outer tubular seal member 160a and an inner tubular seal member 160b; the outer tubular seal member 160a is welded, at its rear end portion, to the inner circumferential surface of a forward-end housing 131, thereby forming a housing-side joint W2; the inner tubular seal member 160b is welded, at its forward end portion, to a forward end portion of the outer tubular seal member 160a, thereby forming an inter-tubular-seal-member joint W3; and the inner tubular seal member 160b is welded, at its portion located rearward of the joint W3, to the outer circumferential surface of the heater 10, thereby forming a heater-side joint W1. An action of pressing the heater forward is effected on the basis of an axial dimension L1 between the joints W2 and W1 shorter than an axial dimension between the joints W2 and W3 and is, therefore, mitigated. |
