Ngk Spark Plug Company, Limited

Yoshihiro Nakamura

Shunsuke Maeda

Masayoshi Matsui

Tadashi Watanabe

Kenjiro Nishiyuki

Masahiro Kawakatsu

Hiroyuki Suzuki

Tomonari Hatta

Tadasi Watanabe

A glow plug () includes: a housing () having a metal shell () and a cap unit (); and a heater unit (). A coupling member () is joined with the housing () and is also joined with the heater unit () at its edge portion (), so as to enable the heater unit () to move along an axis line O and couple the heater unit () with the housing (). When the edge portionof the coupling memberis irradiated with a laser, at least part of the edge portion () melted by laser welding fills a gap () between the coupling member () and the heater unit () to form a welded part (). As a result, even when there is a gap prior to welding, the weld strength between the coupling member () and the heater unit () can be maintained.

Glow plug with pressure sensor

A glow plug including a substantially cylindrical housing extending in an axial direction; a rod-shaped heater unit having a front end protruding from the front end of the housing and movable in the axial direction; a connecting member connecting the heater unit to the housing within the housing and allowing the heater unit to move in the axial direction; and a pressure sensor that detects pressure received by the heater unit. The heater unit has a large-diameter portion at the rear end thereof and a small-diameter portion frontward of the large-diameter portion and having a diameter smaller than the diameter of the large-diameter portion. The connecting member connects the small-diameter portion of the heater unit to the housing within the housing.

Glow plug with combustion pressure sensor

A glow plug wherein a combustion gas prevention wall () extends radially outward on the outer circumferential surface of heater () such that when the heater () is viewed rearward from its forward end () along the axial direction, the combustion gas prevention wall () closes an annular gap Kat a position forward of annular membrane portion () of seal member (). The combustion gas prevention wall () has an outer diameter Dgreater than the inner diameter Dof forward end () of the housing.

A combustion pressure sensor having a tubular housing extending in an axial direction DX, a displacement member disposed within the housing, and a tubular connection member which elastically connects the displacement member to the housing. The combustion pressure sensor has a housing weld Wthat connects the housing and the connection member At least a circumferential portion of the housing weld is a bulge housing weld RWwhich bulges in a radial direction DR.

Combustion pressure sensor and method of manufacturing the same

A combustion pressure sensor () includes a housing () having an axial hole (), a flexible member () fixed at one end to the housing () and being displaceable along the direction of axis (CL), a pressure transmission body () whose outer circumferential surface is fixed to the other end of the flexible member (), and a sensor element () fixed to the housing () and outputting a signal on the basis of a pressure applied thereto from the pressure transmission body (). The housing () includes a main body portion () having a screw portion (), and a cap member () having a press contact portion () which is pressed against the internal combustion engine when the screw portion () is screwed into the mounting hole of an internal combustion engine. The one end of the flexible member () is fixed to the main body portion ().

Combustion pressure sensor

A glow plug with a pressure sensor including a heater member () having a heating element () disposed therein and projecting from a forward end of a metallic shell (), a center rod () having, at its forward end, a connection portion (A) to which a rear end portion of the heating element () is connected, and an annular clearance CR formed between the metallic shell and the heater member in a region located on the forward end side of a junction portion (A) of a deformable member () joined to the heater member. A portion of the heating element located on the forward end side relative to the forward end of the connection portion is at least partially located on the radially inner side of the clearance CR, and the forward end of the connection portion is located on the forward end side relative to the forward end of the junction portion.

A glow plug in which a convex portion () is formed in an outer peripheral surface () of a heater () in a part facing an inner peripheral surface () of a leading end part () of a housing () and interposed in a leading end side annular gap K, so as to maintain a gap with the inner peripheral surface (). A decline in detection accuracy can be prevented to the extent that combustion gas can be received by the leading end () of the convex portion () even if soot clogging should occur.

Glow plug fitted with combustion pressure detection sensor

A seal member () has a dual-tube structure consisting of an outer tubular seal member () and an inner tubular seal member (); the outer tubular seal member () is welded, at its rear end portion, to the inner circumferential surface of a forward-end housing (), thereby forming a housing-side joint W; the inner tubular seal member () is welded, at its forward end portion, to a forward end portion of the outer tubular seal member (), thereby forming an inter-tubular-seal-member joint W; and the inner tubular seal member () is welded, at its portion located rearward of the joint W, to the outer circumferential surface of the heater (), thereby forming a heater-side joint W. An action of pressing the heater forward is effected on the basis of an axial dimension Lbetween the joints Wand Wshorter than an axial dimension between the joints Wand Wand is, therefore, mitigated.

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Iwakura, Japan

Yoshihiro Nakamura