JPS60127683A - Ignition plug - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a spark plug used in an internal combustion engine.

Conventionally, small plugs have not been able to create a wide gap, and when the gap widens, the distance between the end face of the metal shell and the insulator becomes smaller, causing sideways discharge and adversely affecting ignitability. In the case of the type in which the insulator protruded from the end surface of the tubular metal shell, there was a risk of sideways discharge as well as penetration of the insulator in the portion facing the end surface of the metal shell due to the discharge.

This invention was made in view of the above problems, and
The aim is to improve ignition performance and prevent penetration by specifying the relationship between the metal shell, insulator, center constant, and outer electrode.

The structure of this invention will be described in detail below with respect to an embodiment shown in the drawings. In the first embodiment shown in FIG. 1, (1) is a center electrode, (2) is an insulator, and 3) is a metal shell. A three-pole outer electrode (5) is bent and provided on the end face (4), and the center electrode (1) and the insulator (2) are connected to the firing leg (
2a) is made to protrude above the end surface (4) of the metal shell (3), and the discharge is made to pass through the air discharge and the creeping surface of the tip of the insulator (2), and the gap between the air discharge at that time is Outside 1
Assuming that the distance between the tip (6) of the tlI electrode (5) and the creeping surface of the tip of the insulator (2) is 0, the distance between the inner wall (3a) of the end surface of the metal shell (3) and the insulator (2) is The relationship for a certain GB is limited to G·a > GA + 0.4.

For example, in a plug of 1 (1'), Gn is approximately 1 gate, G
/1 is set to 05, the creepage of the insulator (2) is 1.
1 fRll, so the discharge gap length is 1.6 M
becomes.

With this configuration, the inner wall (3) of the end face of the metal shell (3)
Since the distance Go between a) and the insulator (2) is sufficiently larger than the air discharge gap GA, it is possible to ensure discharge with a regular gap and prevent penetration of the insulator (2). .

Next, in the second embodiment shown in Fig. 2, 0]) is the central electrode, ni) is the insulator, and α) is the metal shell, and its end surface α→
A three-pole outer electrode α→ is provided at G, A, which is the gap for air discharge, and the inner wall of the end face of the metal shell α1 (
The relationship between GB, which is the distance between 13a) and the insulator α, is the first
Similar to the example, but further in this example:
Inside the tip of the outer electrode 0υ (1111 (insulator protruding from tfG), the relationship for one height 1 is 0<, 6<1.
0.

With this configuration, due to the relationship p < 1.0, the discharge bf of the normal gap will not pass through the side surface of the insulator 02, but will pass through the tip surface, thereby preventing the occurrence of penetration of the insulator 02. be able to. Due to the close relationship, the discharge follows the tip of the air cap and the insulator, so the radiation voltage does not become too high, and the discharge gap length between the air and the creeping surface can be ensured to ensure ignition. You can increase your sexuality.

As described in detail, the opening of this invention:, the main metal fitting,
By setting the relationship between the outer electrode, the insulator, and the center electrode under specific conditions, even though it is a C1 regular gap spark plug, it has improved inertness, excellent durability, and prevents penetration of the insulator. It produces various effects such as being able to prevent the occurrence of such diseases.

[Brief explanation of drawings]

FIG. 1 is a side view of the crest of the first embodiment of the present invention, and FIG. 2 is a longitudinal sectional side view of the second embodiment. (1+, (11)-...center 11<<Ii, f2
1, (1'J...insulator, (2a)t(12a
)... Ignition leg, (31, αj... Metal shell, (5
), 6 o'clock...outer electrode. Patent applicant Representative patent attorney Miyuki Fujiki Figure 1 Figure 2

Claims (2)

[Claims] (1) The firing leg of the center electrode and the insulator holding the center electrode should protrude from the end face of the metal shell, and the distance between the metal shell and the insulator should also be the same as the air discharge gap between the center electrode and the center electrode. A spark plug characterized by a sufficiently short length. (2) The firing leg of the center electrode and the insulator holding the center electrode protrudes beyond the end face of the metal shell, and the air discharge gap between the center electrode and the center electrode is greater than the distance between the metal shell and the insulator. A spark plug characterized in that the length of the insulator is sufficiently short, and the protrusion length of the insulator is set so that the outer electrode protruding from the metal shell can discharge into the creeping air at the tip of the insulator of the center electrode. .