JPH01274374A - Drawing-in gap type ignitor plug - Google Patents

Abstract

PURPOSE:To suppress the consumption of a grounding electrode and to improve the durability by fixing an insulator in which a center electrode is inserted in a cylindrical main body metal fitting through a ring-form precious metal plate which is welded to the gearing surface at the inner peripheral surface of the tip of the main body metal fitting. CONSTITUTION:An ignitor T is formed of a cylindrical main body metal fitting 1 whose inner periphery of the tip 11 is made smaller in diameter through a ring-form gearing surface 12, a ring-form precious metal plate 4, a cylindrical insulator 3, and a center conductor 2 inserted to the inside of the cylindrical insulator 3. The above ring-from precious metal plate 4 has a cylinder 42 of the size to insert a flange 41 in the form responding to the gearing surface 12 and its outer diameter to insert to the inner surface of the tip 11, and welded to the gearing surface 12 and the inner surface of the tip 11. Moreover, the cylindrical insulator 3 has a tip surface 32 to contact with the gearing surface 12 through the precious metal plate 4, and fixed in the metal fitting 1. And an ignitor 5 is formed including a discharge gap 31 along the surface between the center electrode 2 and the precious metal plate 4. The inner peripheral surface of the tip 11 forms a grounding electrode, and the gearing surface 12 forms a tapered surface.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to igniter plugs used in gas turbine engines, day-to-day engines, gas/oil burner igniters, etc. Concerning countermeasures against plug electrode consumption and extension of life.

[Prior Art] A conventional high-pressure retraction gear type igniter plug will be explained with reference to FIGS. 4 and 5. This igniter brake is
A cylindrical metal shell 100 is formed of a heat-resistant metal such as stainless steel or Inconel (trademark) and has an annular locking surface 101 on the inner periphery of a tip 102. Tip surface 3 engaged with locking surface 101
01 is fitted and fixed. The center electrode 200 is fitted and fixed in the insulator 300, with the tip 201 retracted from the tip surface 301. In this Igna-Ita glove, the inner peripheral surface of the tip 102 of the metal shell 100 is a ground electrode 110.
The firing part 4 is located between the tip 201 of the center electrode and the tip 201 of the center electrode.
00 is formed.

Also, JP-A-5G-67187 and JP-A-63
Publication No. 66879 discloses that a ring-shaped noble metal plate 500 is attached to the locking surface 101 as a countermeasure against wear of the ground ′:rj and pole 110.
An igniter plug R has been proposed in which the igniter plug is welded. In this igniter plug R, the spark discharge surface of the ground electrode 110 is made of an annular noble metal plate 500 to improve heat resistance and durability. This annular noble metal plate 500 is
The heat received by the metal shell 100 is transferred to the metal shell 100 via the welding surface 103.
It was dissipated into

Problem 1 to be Solved by the Invention However, the ignition part 400 of this igniter plug R has the following problems:
High temperature (700℃・-800℃) and electrical energy (1
4 joules), the ground electrode 1
The inner circumferential surface 501 of No. 10 is gradually worn out as time passes. This inventor believes that the wear of the ground electrode 110 occurs slightly earlier than the wear of the ring-shaped noble metal plate 500 in the vicinity of the ground electrode 110 of the annular noble metal plate 500, and that when the igniter plug R is used for a long time, the ground chamber &110 It has been found that a spark consumption portion 104 is generated on the inner periphery of the spark.

An object of the present invention is to provide an igniter plug that can suppress the preceding wear of the ground electrode and significantly increase durability based on the above findings.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a cylindrical main metal fitting whose inner periphery of the tip portion is reduced in diameter through an annular stop surface, and a metal shell that corresponds to the locking surface. an annular noble metal plate having a flange portion and a cylindrical portion having an outer diameter large enough to be fitted into the inner circumferential surface of the tip portion, and brazed to the locking surface and the inner circumferential surface of the tip portion;
Adopts a configuration including a cylindrical insulator having a distal end surface in contact with the locking surface via the annular precious metal plate and fixed within the metal shell, and a center electrode fitted into the insulator. did.

[Functions and Effects of the Invention] The retractable gear type igniter plaque of the present invention produces the following functions and effects.

■The annular precious metal plate has a flange part shaped to correspond to the engagement surface and a cylindrical part whose outer shape is large enough to be fitted into the inner circumference of the tip, and is soldered to the engagement surface and the inner circumference of the tip. .

For this reason, the main surface of the ground electrode at the tip of the metal shell, which contributes to spark discharge, is almost entirely covered with a ring-shaped precious metal plate.
Avoid direct exposure to high temperatures and electrical energy. Therefore, the wear does not precede the annular precious metal plate, and the life of the igniter plug is extended by about 30% compared to the conventional one.

■The amount of precious metal used in the ring-shaped precious metal plate does not increase significantly compared to conventional ones, so the manufacturing cost does not increase significantly.

[Example] Next, a first example of the present invention is shown in FIGS. 1 and 2.

The retractable gear type igniter plug T of the present invention includes a cylindrical metal shell 1 whose inner periphery is reduced in diameter through an annular locking surface 12, and a flange having a shape corresponding to the locking surface 12. An annular noble metal plate 4 having a cylindrical portion 42 having a size such that a portion 41 and an outer diameter are fitted into the inner circumferential surface of the tip portion 11 and brazed to the locking surface 12 and the inner circumferential surface of the tip portion 11; A cylindrical insulator 3 having a distal end surface 32 in contact with the locking surface 12 via an annular noble metal plate 4 and fixed within the metal shell 1.
and a center electrode 2 fitted into the insulator 3. Further, the ignition part 5 is formed including a creeping discharge gap 31 between the center electrode 2 and the annular noble metal plate 4.

The metal shell 1 is made of a cylindrical heat-resistant stainless steel (SUS304) that also serves as a housing for the igniter plug T, the inner peripheral surface of the tip 11 serves as a ground electrode 13, and the locking surface 12 is a tapered surface. ing. In addition, a communication hole 14 is provided in the middle part, and a mounting screw 1 is provided on the outer periphery of the rear end part.
5 is formed. The communication hole 14 is an annular space 16 provided in the axial direction between the metal shell 1 and the insulator 3.
A communication hole 1 provided in the tip portion 11 of the metal shell 1 through the
7 to form a cooling air flow path.

The center electrode 2 is made of a nickel alloy, a tungsten alloy, or the like, and its tip surface 21 is recessed from the tip surface 32 of the insulator 3 by several mm. Further, the rear end surface 22 is connected to a high voltage power source (not shown).

The insulator 3 is made of a sintered body of alumina (A!J203), and the tip surface 32 of the insulator 3 is an inclined surface having a taper angle equivalent to the taper of the locking surface 12. The concave portion 33 has a conical shape.

The firing part 5 includes the tip surface 21 of the center electrode 2 and the insulator 3.
It is constituted by a space with an opening at one end formed between a concave portion 33 at the center of the tip of the annular noble metal plate 4 and the ground electrode 13 including the inner circumferential surface of the annular noble metal plate 4. The spark is in the creeping discharge gap 3 of the insulator 3
1, the air in that space expands explosively, and sparks are emitted from the opening 18 in the form of plasma.

The annular noble metal plate 4 is composed of platinum (Pt) and iridium (Ir).
It is an alloy made by adding 10 to 30% by weight of "C" and has a thickness of 0.
．． It is a thin plate of 2 mm to 0.4 mm, and has a flange part 41 and a cylinder upper part 42, and has a locking surface 12 and a tip part 11, respectively.
It is brazed in contact with the inner peripheral surface. In the figure, a
=1. o~2.0mm, D=1.3d"-1.8dmm
It is.

The brazing was performed using Nicrobraz having the composition and physical properties shown in Table 2 to form layer 6. This Nicrobraz is a nickel brazing material for heat-resistant alloys, which is oxidation and corrosion resistant and does not peel off even at high temperatures of 1100°C. This brazing is performed between the annular precious metal plate 4 and the metal shell 1 in a hydrogen gas atmosphere. Resistance brazing is performed using the Joule heat generated when electric current is passed.

Here, the annular precious metal plate 4 and the locking surface 12 of the metal shell 1
Since the connection with the metal shell 1 is done by brazing,
There is little thermal deformation, and joining requires no effort.

Since the brazing layer 6 has high thermal conductivity, the heat received after mounting is conducted to the metal shell 1 and released, thereby suppressing the wear of the electrodes of the annular noble metal plate 4.

The present invention includes the following embodiments in addition to the above embodiments.

a. The metal shell 1 is made of 72Ni-15Cr-8FeO,5
Inconel 600 with a composition of Cu or Ni
It may also be an alloy such as monic 75 series.

b. For the annular noble metal plate 4, ■Platinum■Iridium may be used alone.

C1 The present invention may be applied to a plug having a structure including an annular space 16 and communication holes 14 and 17 without an air flow path.

d. For brazing, the brazing material used for layer 6 is ■P d -C
u-Ag type palladium solder, (1) JIS Z3261 AgCu type silver solder (BAg-8) having the composition and physical properties shown in Tables 1 and 2, and (2) Cu-Au type gold solder may be used. Here, the silver solder (2) does not contain tin (Sn), zinc (Zn), or cadmium (Cd) so as not to lower the melting temperature.

e. For brazing, gas brazing, furnace brazing, high frequency induction brazing, immersion brazing, carbon rod arc brazing, etc. may be used.

f. As shown in FIG. 3, the metal shell 1 is separated into the metal shell main body IB and the annular electrode tip IA, and the annular noble metal plate 4 is brazed to the annular electrode tip IA in advance and then attached to the metal shell main body IB. It may be fitted and welded, which makes brazing easier.

g. The locking surface 12 is a flat surface and has a good temperature at °C.

Table 1 Table 2

[Brief explanation of the drawing]

11m to 2 show a first embodiment of the retractable gear/tub type igniter plug of the present invention. FIG. 1 is a sectional view of a main part thereof, and FIG. 2 is a sectional view of its entirety. FIG. 3 shows a cross-sectional view of another embodiment. 4 and 5 show cross-sectional views of a conventional igniter plug, FIG. 4 is a cross-sectional view of the main part thereof, and FIG. 5 is a cross-sectional view of the main part of the plug in which the spark consumption part has occurred. In the figure 1... Metal shell 2... Center electrode 3...
Cylindrical insulator 4... Annular noble metal plate 11... Tip portion 12... Locking rlO32... Tip surface 41...
Flange part 42...Cylindrical part T...Retractable gear knob type igniter plug

Claims (1)

[Scope of Claims] 1) A cylindrical metal shell whose diameter is reduced through an annular locking surface on the inner periphery of the tip, a flange portion having a shape corresponding to the locking surface, and an outer diameter of which is inside the tip. It has a cylindrical part large enough to be fitted into the peripheral surface,
A cylindrical insulator having a ring-shaped noble metal plate brazed to a locking surface and an inner circumferential surface of the tip end, and a tip surface abutting the locking surface via the ring-shaped precious metal plate, and fixed within the metal shell. and a center electrode fitted within the insulator.