JPS60114631A - Ceramic glow plug - Google Patents

Abstract

PURPOSE:To prevent a leakage of solder material and to get a quite superior soldering characteristic by a method wherein a connector fitting having a continuous or discontinuous grooves in a substantial circumferential direction and a lead part connected to an inner shaft is fitted to the rear end of the ceramic heater in the inner cavity of the fitting. CONSTITUTION:A connector fitting 11 is formed as a tubular form having a winding clearance 11c by loasely winding or closely a heat-resistive metallic line 11a in a helical form, its one end is pulled out to make a lead part 11b connected to the inner shaft. At the rear end of the ceramic heater 1 is arranged a melting glass material 1a at its outer circumference, one end 2a of the heater 2 is exposed, and directly contacted with the metallic line 11a of the connector fitting 11, thereby the fitting 11 is fitted and connected by a soldering operation. When soldered, the solder material is accumulated in the winding clearance 11c of the metallic wires of the connector fitting 11 and its leakage toward the outside of the unit is prevented, resulting in that a superior soldering is assured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention mainly relates to a glow plug that is installed in a diesel engine and preheats the sub-combustion chamber of the engine head.

Diesel engines generally have poor starting performance, especially at low temperatures, so a glow plug is attached to the auxiliary combustion chamber installed in the engine head, and when electricity is applied to the glow plug, it becomes red hot and some of the fuel injected into the cabin is heated. The method of preheating by combustion is used, and recently there has been a tendency to use it for a long time as an afterglow to stabilize combustion even after starting, and its durability is becoming more and more improved. It is becoming desired.

As this type of glow plug, a ceramic globe 2g is known, which uses a ceramic heater as a heating element, which is made by embedding a heating wire of a high-melting point metal in a ceramic sintered body.
The conventional example has a structure as shown in the vertical sectional view of FIG.

That is, in the figure, the ceramic heater 1 serving as the heating element is
The heating wire 2 is embedded in the upper 2-mick sintered body and soldered to the inner cavity of the multimetallic outer cylinder 3, and one end 2a of the heating wire 2 is electrically connected, and the metal outer cylinder 3 is connected to the mounting bracket. The other end 2b of the heating wire 2 is electrically connected to the metal cap 5 fitted and bonded to the rear end of the ceramic heater 1. and is connected to the tip of the center shaft 7 via a lead electrode shaft 6 welded thereto.

The molten glass material 8 is inserted into the lumen of the mounting bracket 4 so as to embed the above-mentioned components in the lumen as necessary.
The center shaft 1 is configured such that an insulator 9 is interposed between the inner shaft 1 and the mounting bracket 4, and the inner shaft 1 is tightened with a round nut 10 and fixed to the open end of the mounting bracket 4 to serve as an O electrode terminal. be.

By the way, the connection between the rear end of the ceramic heater 1 and the metal cap 5 in the conventional example shown in FIG.
a is exposed, a glass material is interposed on the end face and outer circumferential face except for this part, and the end face 2a of the heating wire is electrically connected to the cap 5. Mug wax, Ou wax, etc. used for soldering are easy to flow because the inner surface of the metal cap 5 has good wettability (during the soldering process, the brazing filler metal escapes outside the soldering area, There is a problem in that it takes time and effort to obtain a good bond, which hinders mass productivity.

The present invention has been made to solve the above problems, and instead of the cap 5 and the lead electrode shaft 6 at the rear end of the ceramic heater 1 shown in FIG. By using a connecting fitting comprising a tubular part that fits into the fitting part and has a continuous or discontinuous groove part formed in the substantially circumferential direction of the fitting part, and a lead part that joins to the center shaft T. Another object of the present invention is to provide a two-mic glow plug that has improved brazing workability and bonding strength and is easy to manufacture.

FIG. 2 shows the above-mentioned connecting fitting according to the present invention. The connecting fitting 11 shown in the same fastening is made by coarsely or tightly wound a heat-resistant metal wire 11L, such as nickel or nickel alloy, in a helical shape. This embodiment is formed into a tubular shape with a winding gap 110, and one end of which is pulled out to form a lead portion 11b that connects to the center shaft. From heat-resistant metal plates,
This is another embodiment in which a slot 11'a is bored and a lead portion 11'b is punched out into a predetermined shape, and then bent into a cylindrical shape.

FIG. 3 (the same parts as in FIGS. 1 and 2 are indicated by the same reference numerals) shows the state of connection of the rear end of the ceramic heater 1 using the spiral connecting fitting 11 shown in the second fastening. In the longitudinal sectional view of the main parts shown, at the rear end of the ceramic heater 1,
A molten glass material 1a is interposed on the outer periphery, and one end 2a of the heat generating 2
is exposed and brought into direct contact with the metal wire lla of the connecting fitting 11, and the fitting 11 is fitted and joined by soldering.

In the connection part at the rear end of the ceramic heater 1 constructed in this way, during soldering with the connection fitting 11, brazing material accumulates in the winding gap 110 of the metal wire of the connection fitting 11 and escapes to the outside. A good soldered joint can be obtained because the protrusion is suppressed), and also when the above-mentioned connecting fitting is a connecting fitting 11' formed from a plate material as shown in Fig. 2 (b). The same effect will not be produced in the case of wax entertainment if wax particles accumulate in the slot 11'a formed on the outer periphery of the cylindrical part.

A strong bond can be obtained.

As can be understood from the above description, the ceramic glow plug of the present invention has a continuous or discontinuous groove-like portion in the circumferential direction at the rear end of the ceramic heater in the inner cavity of the mounting fitting, and a groove-like portion that is continuous or discontinuous in the central shaft. Because it is used by fitting a connecting fitting with a connecting lead part.

During soldering, the brazing material accumulates in the groove-like portion and can be prevented from escaping to the outside, resulting in an extremely good soldered joint.

This ceramic blur plug can be provided as a ceramic blur plug that solves the problems of the conventional technology and is easy to connect and has improved durability.

In addition, the connection structure between the rear end of the ceramic heater and the center shaft using the connecting fitting shown in the embodiment shown in Fig. 2 is such that one end of the heating wire of the heater is electrically connected to the mounting fitting through the metal outer cylinder and grounded. The application is not limited to single-wire glow plugs having a structure as shown in the conventional example in Fig. 1, in which one end is connected to the center shaft, the other end is the side electrode, and the other end is connected to the center shaft, which is the side electrode. It is also possible to use a two-wire glow plug having an electrode structure in which each electrode is insulated and led out from the rear end side of the mounting bracket.

[Brief explanation of drawings]

Fig. 1 is a longitudinal sectional view showing a conventional example of a ceramic glow plug, and Fig. 2 is an example of a connecting fitting according to the present invention.
0 is a front view of a connecting fitting formed by spirally winding metal wire; It is a longitudinal cross-sectional view of the main part showing the connection state using the connection fitting shown in the second lashing. 1: Ceramic heater, 2: Heat generating wire, 2a. 2b End part of the second heat generating wire S3: Metal outer cylinder, 4 2 mounting brackets, 5
: Cap, 6: Lead electrode shaft, T: Center shaft, 11.11
': Connection fitting, 11a two-metal wire, 11b. 11'i): Lead part, 110: Winding gap, 11'a
: #1 hole. Agent Patent Attorney Mamoru Takeuchi

Claims (3)

[Claims] (1) A ceramic heater is made by embedding a heating wire of a high-melting point metal in ceramic powder and sintering it, with a part of the heater protruding from the tip surface of a metal outer cylinder and soldered into the inner cavity. In a ceramic glow plug in which the metal outer cylinder is joined to the tip inner cavity of the mounting bracket. At the connection point between the rear end of the Senmic heater and the center shaft that protrudes from the rear end of the mounting bracket and becomes the terminal electrode. , a connecting fitting comprising a tubular part that fits into the rear end of the ceramic heater and has a continuous or discontinuous groove in the circumferential direction, and a lead part that is joined to the center shaft. A ceramic glow plug characterized by the fact that the mating part is soldered. (2) The connecting fitting is formed by winding a heat-resistant metal wire loosely or tightly spirally to form a tubular part, and one end of which is pulled out to form a lead part. Ceramic gloves 2g. (3) The ceramic glow plug according to claim 1, wherein the connecting fitting is formed into a cylindrical body with a protruding V-shaped portion by punching and bending a heat-resistant metal plate material. .