JP2002206739A - Ceramic glow plug and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce cost by improving assemblage of a self-control type ceramic glow plug 1. SOLUTION: A coiled electric heater 64 made of high melting metal is connected, at an end portion 6d of a ceramics heater 6, to a control coil 13 having a positive temperature coefficient of resistance which is larger than that of the electric heater 64 through a lead wire 11. The other end 13b of the coil 13 is connected to a metal fixture 12 for drawing an electrode. The heater 6 is joined by brazing to the inside of a small diameter portion 8f of a metal outer cylinder 8. The coil 13 and parts 12a, 13b for connecting the coil 13 and the fixture 12, are accommodated in a large diameter portion 8g of the cylinder 8. A space 15 of the portion 8g is filled with a heat resistant insulating powder 14, and an opening portion 4d is fitted with a sealing member 16, followed by riveting an end portion 8e to undergo swaging process. The fixture 12 is then welded to an external joining terminal 18, and the thus obtained assembly is incorporated into a housing 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a glow plug used for assisting starting of a diesel engine.
In particular, a control coil (brake coil) for self-temperature control
The present invention relates to a ceramic glow plug of a self-control type provided with a ceramic glow plug and a ceramic glow plug capable of easily correcting a resistance deviation of a ceramic heater.

[0002]

2. Description of the Related Art Insulating ceramics include a coil made of a high melting point metal (for example, tungsten or the like) or a heating element such as conductive ceramics, or a part of the heating element made of conductive ceramics exposed. A ceramic heater formed by combining ceramics and an inorganic conductor as a heating element is fixed by brazing in a metal outer cylinder, and a lead wire on the negative electrode side of the heating element is taken out from a side surface of the insulating ceramic. While electrically connected to the inner surface of the metal outer cylinder, the positive electrode side lead wire is connected to one end of an electrode extraction metal fitting on the end surface side opposite to the position where the heating element of insulating ceramic is embedded, and further, Conventionally, a ceramic glow plug configured to connect an external connection terminal to the other end of the electrode take-out is known.

A self-temperature-controlling ceramic glow plug in which a control coil (a coil made of a high melting point metal) having a larger positive temperature coefficient of resistance than the heating element of the ceramic glow plug is arranged in series has been widely used. Used. In this self-control type ceramic glow plug, a heating element is arranged at the tip of the glow plug, and a control coil is arranged behind the heating element.

In the self-control type ceramic glow plug, when the temperature is low, both the heating element and the control coil have small resistance values, so that a large current flows through the heating element and the control coil, and the temperature rises rapidly. Then, as the temperature rises, the resistance value of the control coil rapidly increases, so that the current flowing through the heating element decreases, and further temperature rise is suppressed. Since the temperature is controlled by itself, an expensive controller for the temperature control is not required, and the cost is low.

Various types of conventional self-control type ceramic glow plugs are known. For example, Japanese Patent Application Laid-Open No. Sho 59-170620 discloses a ceramic heater having a heating element (heating coil) embedded therein. It is fixed to the internal hole of the housing (engine mounting bracket) via a metal outer cylinder, and the control coil (brake coil) and the external connection terminal are connected to the ceramic heater via an electrode extraction bracket and the like, and the internal hole of the housing is connected. In addition, a configuration is described in which a heat-resistant insulating filler (glass) is filled in a metal outer cylinder to fix the control coil and the like.

Japanese Patent Application Laid-Open No. 60-196164 discloses a control heater in which a ceramic heater in which a heating element (heating coil) is embedded is fixed to one end of an inner hole of a housing via a metal outer cylinder. And a sheath in which the tip of the external connection terminal is embedded is fixed to the other end of the internal hole of the housing,
A configuration in which these are fixed by connection leads is described.

Japanese Patent Application Laid-Open No. 4-257615 discloses a ceramic heater in which a heating element made of conductive ceramics and a control coil are connected in series and buried in insulating ceramics via a metal outer cylinder. Is described.

In Japanese Patent Application Laid-Open No. 61-217623, a heating section and a control section of conductive ceramics are arranged in series, and an external connection terminal is inserted into a hole formed at the center thereof via an insulating member. The configuration described above is connected to the heating section.

[0009]

The first and second publications (JP-A-59-170620, JP-A-60-19)
No. 6164), when the ceramic heater and the control coil are separated from each other, it is difficult to position the control coil and the external connection terminals when the ceramic heater and the control coil are separated from each other. ,
In addition, it is difficult to reliably connect them. In addition, since the number of components to be incorporated into the housing at the time of assembling is large, there is a problem in assemblability and reliability, and the cost is increased.

Further, the third and fourth publications (JP-A-4-257615, JP-A-61-217623)
When the heating element (heating coil) and the control unit (control coil) are both arranged inside the ceramic heater as in the self-control type ceramic glow plug described in, the distance between the heating unit and the control unit Satisfactorily, the self-temperature controllability is poor, and the structure of the ceramic heater is complicated and the molding process becomes complicated. Furthermore, there are various problems in terms of productivity, strength, cost, and the like, such as the length of the ceramic heater being increased by the amount corresponding to the arrangement of the control coil, and the mechanical strength of the ceramic heater being reduced. .

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. By integrally connecting a control coil to a ceramics heater, the present invention has an excellent assemblability and reliability, and is capable of reducing costs. It is an object of the present invention to provide a control type ceramic glow plug. Another object of the present invention is to provide a self-controllable ceramic glow plug which has a simple ceramic heater and can be reduced in length, thereby reducing manufacturing costs and having high productivity and excellent strength. It is assumed that.

In the ceramic glow plug, in order to control the temperature of the ceramic heater and control the maximum attainable temperature, it is very important to regulate the resistance of the heating element within a required range. Ceramic heaters adjust the resistance value by mixing an inorganic conductor and an inorganic insulator. It is very difficult to obtain a predetermined resistance value due to factors such as imbalance during sintering.

These circumstances are not problems unique to the ceramic glow plug, but are common to the entire ceramic heater. Particularly, in the ceramic glow plug, the temperature conditions to be used are severe, and furthermore, the ceramic glow plug is supplied from the vehicle. Since the voltage is about 12 V and the required shape is small and the degree of freedom is low, it is difficult to design a resistor, and it is very difficult to suppress a change in the resistance value resulting from these variations. There's a problem.

Therefore, a special sintering method called a hot press method has conventionally been employed in ceramic glow plugs. In the hot press method, since sintering proceeds with the help of external force, many of these variation factors can be reduced. That is, it is possible to greatly reduce the variation in the sintering density and the unbalance during sintering, and suppress the variation in the resistance value to a range that does not hinder practical use. However, the hot press method is not a preferable method from the viewpoint of mass productivity because the equipment itself is very expensive, the near net shape processing is difficult, and the grinding cost is high. This has been a major factor in that ceramic glow plugs are more expensive than metal glow plugs.
Further, even when the hot press method is adopted, very strict quality control is required to obtain a predetermined resistance value, which further increases the cost.

Therefore, another invention has been made in order to solve the above-mentioned problem, and it is possible to adjust the variation of the resistance value of the ceramic heater, thereby realizing practical use without using an expensive method called hot pressing. It is an object of the present invention to provide a ceramic glow plug having heat generation characteristics without any problem and capable of being produced at low cost.

[0016]

According to a first aspect of the present invention, there is provided a self-control type ceramic glow plug, comprising a ceramic heater formed of insulating ceramics and an inorganic conductor, and the ceramic heater fixed in one end. And a metal outer cylinder having the other end fixed to the inner hole of the housing, and a control coil having a larger positive resistance temperature coefficient than the heating element connected to one pole of the heating element, An electrode take-out fitting connected to the other end of the control coil, and in particular, the electrode take-out fitting is formed of a rigid body, and the control coil and a connection portion between the control coil and the electrode take-out fitting are provided. Are housed in the metal outer cylinder, and the control coil and the electrode take-out fitting are fixed to the metal outer cylinder via an insulator.

Further, the invention according to claim 2 is characterized in that the insulator is a heat-resistant insulating powder filled in a metal outer cylinder and densified by swaging. is there.

Further, the invention according to claim 3 is characterized in that the metal outer cylinder has a stepped shape having a small diameter portion to which the ceramic heater is fixed and a large diameter portion fixed to the housing. The control coil is arranged in the large diameter portion.

Further, the invention according to claim 4 is characterized in that the control coil is disposed inside a front end of the housing.

The invention according to claim 5 is characterized in that one pole of the ceramic heater and the control coil are connected via a lead wire.

According to a sixth aspect of the present invention, an insertion hole is formed in the end surface of the electrode take-out fitting.
One end of the control coil is inserted into the insertion hole and connected.

According to a seventh aspect of the present invention, the insertion hole is a through-hole passing through the electrode take-out in the axial direction. The connection with the control coil is performed by plastically deforming the outer periphery.

The invention according to claim 8 is characterized in that the side surface of the distal end portion of the control coil is connected to the side surface of the distal end portion of the electrode take-out fitting.

According to a ninth aspect of the present invention, the distal end of the control coil is formed in a coil shape, and the distal end of the electrode extraction fitting is inserted and connected to the coil-shaped portion. Things.

Further, the invention according to claim 10 is a ceramic heater formed of insulating ceramics and an inorganic conductive material as a heating element, wherein the ceramic heater is fixed in one end and the other end is a housing. A ceramic glow plug including a metal outer cylinder fixed to an internal hole, a resistor connected to one pole of the heating element, and an electrode extraction metal fitting connected to the other end of the resistor. Depending on the resistance of the ceramic heater,
By combining resistors having different resistance values and connecting them in series, the resistance value of the ceramic heater is corrected to make the overall heat generation characteristics substantially the same.

[0026] According to a further aspect of the present invention, there is provided a ceramics heater formed of insulating ceramics and an inorganic conductive material as a heating element, wherein the ceramics heater is fixed in one end and the other end is a housing. A ceramic glow plug including a metal outer cylinder fixed to an internal hole, a resistor connected to one pole of the heating element, and an electrode extraction metal fitting connected to the other end of the resistor. The electrode extraction metal fitting side of the resistor is formed in a coil shape, a screw portion is formed at the tip of the electrode extraction metal fitting, and the screw portion is screwed into the coil-shaped portion to connect the resistor with the electrode extraction metal fitting. And, and configured to adjust the screwing position of the electrode extraction metal fittings, measure the resistance value of the ceramic heater and resistor connected in series, By adjusting the screwed position of the electrode fitting in accordance with the measurements, and is characterized in that it has substantially the same heat generation characteristic of the entire by correcting the resistance value of the ceramic heater.

According to a twelfth aspect of the present invention, in the ceramic glow plug according to the tenth or eleventh aspect, the electrode take-out fitting is formed of a rigid body, and the resistor and the resistor and the electrode take-out are formed. The connection portion with the metal fitting was accommodated in the metal metal cylinder, and the resistor and the electrode take-out metal were fixed to the metal metal cylinder via heat-resistant insulating powder densified by swaging. It is characterized by the following.

According to a thirteenth aspect of the present invention, there is provided a method of manufacturing the self-control type ceramic glow plug according to any one of the first to ninth aspects, wherein one end of the control coil is a rigid body. Connecting the other end of the control coil to one pole of the ceramic heater, fixing the ceramic heater in the metal outer cylinder, and connecting the other end of the control coil to the one end of the metal heater. A step of filling a heat-resistant insulating powder from an opening of the outer cylinder, and a swaging process on an outer peripheral portion of the outer cylinder made of metal in which a connection portion between the control coil and the electrode extraction metal fitting is housed. By reducing the diameter,
And a step of fixing the control coil and the electrode take-out fitting to a metal outer cylinder.

A manufacturing method according to a fourteenth aspect of the present invention relates to a method of connecting the one end of the control coil to one pole of a ceramic heater and fixing the ceramic heater to one end of a metal outer cylinder. Connecting the other end of the control coil to one end of the electrode take-out fitting, filling the heat-resistant insulating powder from the opening of the metal outer cylinder, and forming the control coil and the electrode take-out fitting inside. A step of fixing the control coil and the electrode extraction metal fitting to the metal outer cylinder by sequentially reducing the outer peripheral portion of the metal outer cylinder in which the connection portion is accommodated by swaging. Is what you do.

According to a fifteenth aspect of the present invention, in the method of the first aspect, the metal outer cylinder has a small diameter at a portion where the ceramic heater is fixed, and a control coil and a connection between the control coil and an electrode extraction metal fitting. The portion into which the portion is inserted has a large diameter, and the large diameter portion is reduced in size by swaging.

[0031]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to an embodiment shown in the drawings. FIG. 1 is a vertical cross-sectional view of a ceramic heater type glow plug according to an embodiment of the present invention (the whole is indicated by reference numeral 1), and FIG. 2 is an enlarged view of a main part thereof. The housing 2 of the ceramic glow plug 1 is substantially cylindrical, and has a stepped axial hole 4 formed therein. The central portion 4b of the internal hole 4 of the housing 2
Has a small diameter, and a middle diameter portion 4a slightly larger in inner diameter than the small diameter portion 4b is formed on the left side of the figure for fixing a ceramic heater described later. Opening 4 located to the left of medium diameter portion 4a to which the ceramic heater is fixed
“e” has a slightly larger inner diameter than the ceramic heater fixing portion (medium diameter portion) 4a. The right side in FIG. 1 for fixing the external connection terminal and the insulating member is a large diameter portion 4c.

In a middle diameter portion 4a of the internal hole 4 (stepped axial hole) of the housing 2, a metal outer cylinder 8 to which a ceramics heater 6 is joined by brazing (silver brazing).
The rear end 8c side is press-fitted or inserted and fixed by brazing or the like.

The ceramic heater 6 has a heating wire (heating element) 64 in which a high-melting metal (for example, tungsten (W) or the like) is coiled and embedded in a ceramic insulator 62 constituting a main body thereof. The heat-generating portion 6a protrudes outward from the distal end 8b of the metal outer tube 8, and the rear side of the heat-generating portion 6a is inserted into the metal outer tube 8, The end face 6b is located inside the metal outer cylinder 8. In this embodiment, the heating element 64 is made of a high melting point metal. However, the heating element 64 may be made of conductive ceramics or a sheet-like heating element, and a part of the heating element of the conductive ceramic is exposed from the insulating ceramic. For example, the ceramics heater 6 may be any as long as it is formed by combining insulating ceramics and an inorganic conductor as a heating element.

One end (negative electrode side end) 6 of the coil-shaped heating wire 64 embedded in the ceramic heater 6
4 a is a ceramic insulator 6 inside the metal outer cylinder 8.
2 and is electrically connected to the inner surface of the metal outer cylinder 8 by brazing. On the other hand, the coil-shaped heating wire 6
The positive electrode side end portion 64b of the fourth extends toward the rear end surface 6b of the ceramic heater 6, and is connected to one end 11a of the positive electrode lead wire 11 inside the ceramic heater 6. The positive electrode side lead wire 11 is made of a Ni wire or a Ni-plated mild steel wire.

When one end 11a of the positive electrode lead wire 11 is connected to the positive electrode end 64b of the coiled heating wire 64 of the ceramic heater 6, a lead wire mounting hole is formed in the rear end 6d of the ceramic heater 6. 6c is formed, and the side surface of the end 64b of the coiled heating wire 64 is exposed in the lead wire mounting hole 6c. The leading end 11a of the positive electrode side lead wire 11 is inserted into the lead wire mounting hole 6c.
Is inserted and brazed (silver brazed), thereby electrically connecting the end 64b of the coiled heating wire 64 and the positive lead 11.

The other end 11b of the positive lead 11 taken out from the end face 6b of the ceramic heater 6 is connected to one end 13a of the control coil 13. The control coil 13 is formed by winding a metal wire having a relatively high temperature coefficient of resistance into a coil shape, and one end 13a thereof is joined to the positive electrode lead wire 11 by welding (spot welding) or the like as described above. At the same time, the side surface of the other end 13b is joined by spot welding or the like to the side surface of the one end portion 12a of the electrode extraction fitting 12 made of a rigid body. The control coil 13
And the positive electrode side lead wire 11 may be integrally formed.

The metal outer cylinder 8 has a stepped shape having a small diameter portion 8f on the front side to which the ceramic heater 6 is fixed and a large diameter portion 8g on the rear side. A rear end 8 c of 8 g is fixed in the internal hole 4 of the housing 2. The ceramic heater 6 is fixed in the small-diameter portion 8f of the metal outer cylinder 8 as described above, and in the large-diameter portion 8g, the control coil 13 and a connection portion between the control coil 13 and the electrode extraction metal fitting 12 are provided. 12a, 13b
Is housed. The control coil 13 in the metal outer cylinder 8
Around the portion in which the electrode fittings 12 are accommodated, an insulator 14 made of heat-resistant insulating powder and densified by swaging is filled.
The control coil 13 and the electrode take-out fitting 12 are fixed to the metal outer cylinder 8 via the. Further, a seal member 16 is fitted between the inner surface of the opening of the metal outer cylinder 8 and the outer surface of the electrode extraction fitting 12.

The control coil 13 is located near the small diameter portion 8f within the large diameter portion 8g of the metal outer cylinder 8 (the ceramic heater 6).
Side), and when the metal outer cylinder 8 is fixed to the housing 2, the metal outer cylinder 8 is located inside the vicinity of the distal end 2 a of the housing 2.

The other end 12b of the electrode take-out fitting 12 whose one end 12a is fixed to the positive electrode lead wire 11 in the metal outer cylinder 8 projects outside from the metal outer cylinder 8.
The end 18b of the external connection terminal 18 is connected to the end 12b by butt welding or the like.

As described above, the ceramic heater 6 and the metal outer cylinder 8 are fixed to the housing 2. In this state, the screw portion 18b at the end (the right end in FIG. 1) of the external connection terminal 18 is removed from the housing 2. A sealing member (O-ring) 20 and a cylindrical insulating bush 22 are fitted from the threaded portion 18 b side projecting toward the outside, and are inserted into the large-diameter portion 4 c of the internal hole 4 of the housing 2. Further, a washer-shaped insulating member 24 is fitted from the outside, and the insulating bush 22 is fixed by tightening an aluminum nut 26. Large-diameter portion 4 of internal hole 4 of housing 2
As for c, the small diameter portion 4b side has a tapered surface 4f, and the inside of the housing 2 is kept airtight by pressing the seal member 20 between the tapered surface 4f and the insulating bush 22. The seal member 20 and the insulating bush 2
2 can be fixed by caulking the end of the housing 2, but fixing with the aluminum nut 26 does not require a caulking step, and is advantageous in cost.

However, the fixing structure of the external connection terminal 18 is not limited to the above-mentioned structure, but may be fixed by another method. For example, as described in Japanese Patent Application No. 2000-084659 or the like, an insulating fixing member is provided between the inner surface of the housing 2 and the outer surface of the external connecting terminal 18, and tightening acting on the external connecting terminal 18 by the insulating fixing member. Torque can also be applied.

In the self-control type ceramic glow plug 1 having the above-described structure, the positive lead wire 11 and the control coil 13 and the control coil 13 and the electrode extraction metal fitting 12 taken out of the ceramic heater 6 are made of metal. The control coil 13 and the electrode take-out fitting 12 are connected inside the tube 8, and are fixed to the metal outer tube 8 by an insulator 14 filled in the metal outer tube 8. Thus, the control coil 13 is connected to the ceramic heater 6.
Are integrated, the assembly of the glow plug 1 is very easy, and the number of components to be assembled in the housing 2 is small, so that workability is good and cost can be reduced.

Although the ceramic heater 6 and the control coil 13 are integrated, unlike the conventional structure in which the control coil 13 is incorporated inside the ceramic heater 6,
Since the necessary distance between the heating element 64 and the control coil 13 can be ensured, the temperature controllability is excellent. In addition, since the ceramic heater 6 can be shortened, the overall cost can be reduced.

Further, since the structure is similar to that of a conventional self-control type metal glow plug in which a heat generating coil and a control coil are fixed by filling a metal sheath with heat-resistant insulating powder and performing swaging processing, The equipment for press-fitting the metal outer cylinder 8 into the housing 2 can be shared. Further, since the control coil 13 is fixed in the insulator 14 in which the heat-resistant insulating powder is densified by swaging, it is easy to keep the control coil portion airtight.

Next, the procedure for assembling the self-controlling ceramic glow plug 1 having the above-described structure will be described with reference to FIGS. 1, 2, and 3 to 5. First, the positive electrode lead wire 11 (Ni wire or N wire) welded (spot welded) to one end 13a of the control coil 13 is inserted into the positive electrode lead wire mounting hole 6c formed on the end face 6b of the ceramic heater 6.
One end 11a of an i-plated mild steel wire) is inserted and brazed with silver, and a rigid electrode extraction metal fitting 12 is welded to the other end 13b of the control coil 13 to form an assembly (see FIG. 3A). In this embodiment, the end 13 of the control coil 13
The side surface of b is brought into contact with the side surface of the tip portion 12a of the electrode take-out fitting 12, and is fixed by spot welding.

The ceramic heater 6 as the assembly
In a state where the heat generating portion 6a is exposed to the outside.
And fixed to the metal outer cylinder 8 by silver brazing. In a state where the ceramic heater 6 and the metal outer cylinder 8 are joined by silver brazing, as shown in FIG. 3B, the control coil 13 is close to the small-diameter portion 8f in the large-diameter portion 8g of the metal outer cylinder 8. And connection portions 12a and 13b between the control coil 13 and the electrode extraction fitting 12.
Is also located in the metal outer cylinder 8.

Here, a brief description will be given of an assembling procedure when the ceramic heater 6 is fixed in the metal outer cylinder 8 by brazing. First, the metal outer cylinder 8 is set on the brazing jig. A plurality of metal outer cylinders 8 and ceramic heater assemblies are set and brazed simultaneously. Next, the wire material was wound in a coil shape on the end face 6b of the assembly of the ceramic heater 6 (the state shown in FIG. 3A) in which the positive electrode side lead wire 11, the control coil 13, and the electrode extraction metal fitting 12 were connected. A brazing material (silver brazing material) is set, and it is fitted and set in the metal outer cylinder 8. Thus, the metal outer cylinder 8 and the ceramic heater 6 are positioned. Then, the brazing material is melted by heating, and the ceramic heater 6 and the metal outer cylinder 8 are brazed.

As described above, the stepped metal outer cylinder 8
After the ceramic heater 6 is fixed therein by silver brazing, the opening 15d on the large-diameter portion 8g side of the metal outer cylinder 8 is inserted into the space 15 in which the control coil 13 and one end of the electrode extraction metal fitting 12 are accommodated. A heat-resistant insulating powder 14 (for example, magnesia (MgO) or the like) is filled (see FIG. 3C).
After filling with the heat-resistant insulating powder 14, the powder near the opening 8d of the metal outer cylinder 8 is removed to secure a space 17 into which the sealing member 16 is inserted (see FIG. 3D).

Next, a rubber seal member 16 (silicone rubber, fluorine rubber, or the like) is inserted into a space 17 in the opening 8d of the metal outer cylinder 8 (see FIG. 4A). By inserting the sealing member 16 into the opening 8d of the metal outer cylinder 8, it is possible to prevent the heat-resistant insulating powder 14 from spilling when swaging is performed in a later step. Further, it is possible to prevent the electrode fitting 12 from contacting the inner surface of the metal outer cylinder 8. Thereafter, the end of the metal outer cylinder 8 is swaged (see reference numeral 8e in FIG. 4B) so that the sealing member 16 does not fall off.

As shown in FIG. 4 (b), after filling the heat-resistant insulating powder 14 into the metal outer cylinder 8, inserting the sealing member 16 and caulking the end 8 e of the metal outer cylinder 8. , Control coil 13 and control coil 13 and electrode take-out fitting 12
By swaging the large-diameter portion 8g of the metal outer cylinder 8 in which the connection portions 12a and 13b are accommodated,
Small diameter portion 8f to which the ceramic heater 6 is fixed
The diameter is reduced to a slightly larger diameter. By reducing the outer diameter of the large-diameter portion 8g of the metal outer cylinder 8 by swaging as described above, the heat-resistant insulating powder 14 is densified, and the control coil 13 and the electrode extraction metal fitting 12 are made of metal. It is fixed in the outer cylinder 8 (see FIG. 4C). The outer diameter of the reduced diameter portion may be substantially the same as the outer diameter of the portion where the ceramic heater 6 is fixed (small diameter portion 8f).

One end 18a of the external connection terminal 18 is fixed to the outer end 12b of the metal fitting 12 fixed to the metal outer cylinder 8 by swaging as described above by butt welding or the like (see FIG. 5). ). The sub-assemblies shown in FIG. 5 (the ceramic heater 6, the metal outer cylinder 8, the control coil 13, the electrode extraction fitting 12, the external connection terminal 18)
) Is connected to the battery connection screw portion 1 of the external connection terminal 18.
With the 8b side first, the housing 2 is inserted into the inner hole 4 from the ceramic heater fixed side end (left end in FIG. 1), and is fixed by press-fitting or brazing (silver brazing) or the like.

When the sub-assembly is fixed to the housing 2, the terminal thread 18 b of the external connection terminal 18
Project out of the housing 2. This screw part 1
As described above, a seal member (O-ring)
20 and the cylindrical insulating bush 22 are fitted together, inserted into the large-diameter portion 4c of the internal hole 4 of the housing 2, further fitted with a washer-shaped insulating member 24 from the outside, and an aluminum nut 26 is attached. By tightening and fixing, the self-control ceramic glow plug 1 shown in FIG. 1 is assembled.

As described above, by performing swaging in a state where the control coil 13 is accommodated inside the metal outer cylinder 8, the ceramic heater 6 and the control coil 13 can be easily integrated. Since the integrated ceramic heater 6, control coil 13 and electrode take-out fitting 12 are assembled into the housing 2, the workability is extremely good, and the number of components incorporated in the housing 2 is small, and the assemblability and reliability are excellent. In addition, the cost can be reduced.

FIGS. 6 to 8 are views showing the procedure for assembling the self-control type ceramic glow plug 1 according to the second embodiment. In this embodiment, first, the ceramic heater 6 and the metal external After the tube 8 and the positive electrode side 64b of the coil-shaped heating wire 64 of the ceramic heater 6 and the end 13a of the control coil 13 are simultaneously brazed and integrated, the electrode extraction fitting 1 is attached to the other end 13c of the control coil 13.
2 is connected, and then swaging is performed to make a fixed and electrical connection. In this embodiment, the end 13 on the fixed side of the control coil 13 to the ceramic heater 6 is provided.
The control coil 13 is directly connected to the positive electrode side 64b of the coil-shaped heating element 64 of the ceramics heater 6, omitting the positive electrode side lead wire 11 of the first embodiment.

When brazing the ceramic heater 6, the control coil 13 and the metal outer cylinder 8, a large diameter portion 8g is formed on the outer periphery of the ceramic heater 6 on the side fixed to the housing 2 (upper part in FIG. 6). With the lower portion (small-diameter portion 8f) of the metal outer cylinder 8 set in the fitted state, it is set on a brazing jig (not shown), and the wire is wound in a coil shape on the end surface 6b of the ceramic heater 6. Set the brazing material that has
b into the mounting hole 6c where the positive electrode side 64b of the coil-shaped heating wire 64 formed at the end 13b of the control coil 13 is exposed.
a, and heated to a predetermined temperature (for example, 900 degrees)
Melt the silver brazing material. The melted silver brazing material flows into the gap between the inner surface of the metal outer cylinder 8 and the outer surface of the ceramic heater 6 and the gap between the inner surface of the mounting hole of the ceramic heater 6 and the outer surface of the control coil 13 and is simultaneously brazed. (See FIG. 6A).

Further, in this embodiment, FIG.
As shown in FIG. 6, the distal end (the lower end in FIG. 6) 12c of the electrode take-out fitting 12 has a small diameter and the control coil 13
The other end 13c (upper end in FIG. 6) of the control coil 1 is wound into a small-diameter coil having an inner diameter substantially equal to the outer diameter of the tip small-diameter portion 12c of the electrode extraction fitting 12.
The small-diameter portion 12c at the tip of the electrode take-out fitting 12 is inserted into the small-diameter coil-shaped portion 13c.

Subsequently, the same steps as in the first embodiment are performed. That is, the heat-resistant insulating powder 14 is placed in the upper space 15 (see FIG. 6B) on the large-diameter portion 8g side of the metal outer cylinder 8.
(See FIG. 6C), and the opening 8 of the metal outer cylinder 8 is filled.
The heat-resistant insulating powder 14 near the entrance of d is removed and the space 1 is removed.
7 (see FIG. 6D). Next, the metal outer cylinder 8
After the sealing member 16 is inserted into the opening 8d of FIG.
(See (a)), the end portion 8e of the metal outer cylinder 8 is caulked to prevent the sealing member 16 from falling off (see FIG. 7B). Thereafter, the large diameter portion 8g of the metal outer cylinder 8 is swaged to reduce the diameter to be slightly larger than the small diameter portion 8f to which the ceramic heater 6 is fixed (FIG. 7 (c)). reference).

The outer end 12b of the electrode fitting 12 fixed in the metal outer cylinder 8 by swaging.
Then, one end 18a of the external connection terminal 18 is fixed by butt welding or the like (see FIG. 8). The subassembly (the ceramic heater 6, the metal outer cylinder 8,
The self-control ceramic glow plug 1 is formed by inserting and fixing the control coil 13, the electrode extraction fitting 12, the external connection terminal 18 and the like into the housing 2 as described above.
Assemble. The self-control type ceramic glow plug 1 according to this embodiment can also provide the same effect as the glow plug of the first embodiment. The control coil 1 is attached to the small-diameter portion 12 d of the tip of the electrode fitting 12.
A stepped portion may be provided so as not to easily come out after being inserted into the small-diameter coil-shaped portion 13c of No.3. In this way, it is possible to prevent the tip small diameter portion 12d of the electrode take-out fitting 12 from coming out of the small diameter coil-shaped portion 13c of the control coil 13 in a subsequent step.

Further, in the assembling procedure of this embodiment, the merit in manufacturing is greater than that of the first embodiment.
In the above-described embodiment, the electrode heater 12 is connected to the control coil 13 fixed to the ceramic heater 6 first, and then the ceramic heater 6 is brazed to the metal outer cylinder 8. In addition, the entire length of the ceramic heater assembly is long, so that it is difficult to perform a large number of brazing operations at one time, and the control coil 13 is bent due to the weight of the electrode take-out fitting 12 during brazing, and correction is required. May be. Further, there is a problem that it is difficult to set the coil-shaped brazing material because the electrode take-out fitting 12 is in the way or that the electrode take-out fitting 12 cannot be set if its outer diameter is larger than the inner diameter of the metal outer cylinder 8. Moreover, the ceramic heater 6 and the control coil 13
Since the brazing to the positive electrode lead wire 11 connected to the control coil 13 and the brazing to the ceramic heater 6 and the metal outer cylinder 8 are performed separately, two brazing steps are required. It is.

On the other hand, in this embodiment, the ceramic heater 6 and the metal outer cylinder 8, the ceramic heater 6
And brazing of the control coil 13 in one process,
Since the electrode extraction fitting 12 is connected (or may be provisionally connected) to perform the swaging process, all the problems in the assembling procedure as described above are eliminated.

FIG. 9 shows the structure of a main part of a self-control type ceramic glow plug 1 according to a third embodiment and a procedure for assembling the same. In this embodiment, a tip 12d of an electrode take-out fitting 12 is shown. As well as
The end 13 d of the control coil 13 is attached to the small-diameter tip 12 d.
An insertion hole 12e for inserting the b is provided (see FIG. 9B). Note that portions not shown are the same as those in the above embodiments, and therefore the same reference numerals are used for the description.

In this embodiment, the positive electrode side lead wire 11 is welded to one end 13a of the control coil 13 in advance, the ceramic heater 6 is fitted into the small diameter portion 8f of the metal outer cylinder 8, and End 11a of side lead wire 11
Are inserted into the mounting holes 6c of the ceramic heater 6, and the ceramic heater 6, the metal outer cylinder 8, and the ceramic heater 6 and the control coil 13 (the positive lead 11 of the control coil 13) are simultaneously brazed.

Next, the control coil 1 is inserted into an insertion hole 12e formed in the small-diameter portion 12d at the distal end of the electrode extraction fitting 12.
3 is inserted, and then the heat-resistant insulating powder 14 is filled and the heat-resistant insulating powder 14 in the vicinity of the opening 8d of the metal outer cylinder 8 is removed by the same procedure as in each of the above embodiments. , Insertion of the seal member 16, caulking of the end 8e of the metal outer cylinder 8, and swaging. By reducing the diameter of the large-diameter portion 8g of the metal outer cylinder 8 by swaging, the small-diameter portion 1 at the tip of the electrode fitting 12 is reduced.
2d is deformed and firmly fixed to the control coil 13, so that electrical connection is reliably performed. In this embodiment, the same effects as those of the above embodiments can be obtained.

FIG. 10 shows a configuration of a main part of a self-control type ceramic glow plug 1 according to a fourth embodiment and an assembling procedure thereof.
Connection side 13 of control coil 13 to electrode extraction fitting 12
In the state where the other end portion 13a (the lower end portion in FIG. 10) of the control coil 13 is connected to the coil-shaped heating wire 64 of the ceramic heater 6 via the positive lead wire 11, The outer cylinder 8 extends outward from the opening 8d (see FIG. 10A).

In this embodiment, one end 13a of the control coil 13 is also mounted at the time of assembly, as in the third embodiment.
The positive electrode side lead wire 11 is welded in advance, the ceramic heater 6 is fitted into the small diameter portion 8f of the metal outer cylinder 8, and the end 11a of the positive electrode side lead wire 11 is attached to the mounting hole of the ceramic heater 6. 6c, and the ceramic heater 6 and the metal outer cylinder 8 and the ceramic heater 6 and the control coil 13 are simultaneously brazed.

Further, a through hole 12f in the axial direction is formed in the electrode take-out fitting 12, and the extended end 13d of the control coil 13 is inserted into the through-hole 12f of the electrode take-out fitting 12, and swaged. The electrode take-out fitting 12 and the control coil 13 are fixed and electrically connected by, for example, the above.

As described above, one end 13a is connected to the ceramics heater 6 and the other end 13d is extended to the outside of the metal outer cylinder 8 at the end 13d of the control coil 13 extending to the outside. After connecting the take-out fitting 8, the heat-resistant insulating powder 14 is filled in the space 15 on the large-diameter portion 8 g side of the metal outer cylinder 8, and the opening The heat-resistant insulating powder 14 near the portion 8d is removed, the sealing member 16 is inserted into the vacant space 17, the end 8e of the metal outer cylinder 8 is swaged, and then swaging is performed. This swaging process also forges the electrode take-out fitting 12, so that the electrical connection between the control coil 13 and the electrode take-out fitting 12 is ensured. Therefore,
The electrical connection between the control coil 13 and the electrode take-out fitting 12 before the swaging process may be temporarily fixed. Also,
The electrical connection between the control coil 13 and the electrode take-out fitting 12 may be performed only by caulking the outer periphery of the electrode take-out fitting 12 before or after the swaging process. Thereafter, a portion of the control coil 13 protruding from the electrode take-out fitting 12 is cut.

Next, the end portion 12g of the electrode take-out fitting 12
Then, the end 18a of the external connection terminal 18 is connected by butt welding, and this subassembly is inserted into the housing 2 and fixed to assemble the self-controlling ceramic glow plug 1.

The assembling procedure of this embodiment is as follows. The electrode extraction lead wire 1 is inserted into the through hole 12f of the electrode extraction fitting 12.
Third Embodiment (FIG. 9) in that 0 is inserted and fixed.
However, in the third embodiment, since the operation of inserting the end portion 13b of the control coil 13 into the insertion hole 12e of the electrode extraction fitting 12 inside the metal outer cylinder 8 is performed, the control coil 13 Is difficult to insert, and it is also difficult to confirm whether or not the insertion has been successful. Therefore, there is a possibility that a connection error may occur. Since the electrode is inserted into the through-hole 12f of the metal fitting 12 outside the tube 8, the insertion operation is easy and it can be confirmed that the insertion has been performed securely. Therefore, there is no possibility that a connection error occurs, which is advantageous in quality control.

In the fourth embodiment, the end 13d of the control coil 13 is extended to the outside of the metal outer cylinder 8, but instead of extending the control coil 13 itself, Another lead wire may be welded to the end of the control coil 13.

FIG. 11 is a longitudinal sectional view showing the entire structure of a self-control type ceramic glow plug 1 according to a fifth embodiment. The metal outer cylinder 8 of the first embodiment is connected to a housing 2. Control coil 1
3 is located inside the housing 2.

In this embodiment, a middle diameter portion 4a for fixing the metal outer cylinder 8 of the inner hole 4 of the housing 2 is provided near the center of the housing 2, and the metal outer cylinder 8 is greatly extended.
The end 8c of the large diameter portion 8g is press-fitted or inserted into the middle diameter portion 8a and fixed. And control coil 1
3, one end 13a of the long positive lead 11
1b is fixed by welding or the like, and the other end 11a of the positive electrode side lead wire 11 is connected to the coil-shaped heating element 64 of the ceramic heater 6. Therefore, the control coil 13 is located inside the housing 2. Other configurations and assembling procedures are the same as those in the first embodiment.

In the first embodiment, the control coil 1
3 is located on the distal end portion 2a side of the housing 2 and the length of the metal outer cylinder 8 can be shortened, so that workability such as swaging is good. Since the temperature is close to 6a, even a slight change in temperature of the heat generating portion 6a is picked up, and the temperature controllability, that is, the stability of the temperature control may be deteriorated. On the other hand, in the configuration of the fifth embodiment, the metal outer cylinder 8
, The workability of swaging or the like is not very good, but since the control coil 13 can be separated from the heat generating portion 6a of the ceramic heater 6, the effect of improving the temperature controllability can be obtained. Further, in the fifth embodiment, it is possible to prevent the heat generated by the control coil 13 from affecting the brazing portion between the ceramic heater 6 and the metal outer cylinder 8, and the brazing portion becomes high in temperature and mechanically. It is possible to prevent the strength and airtightness from being reduced.

FIG. 12 is a view for explaining the structure of a main part of a ceramic glow plug 1 according to a sixth embodiment. Although not shown, the first embodiment shown in FIGS. It has almost the same configuration as that of the embodiment.
Therefore, parts that are not shown in the drawings will be described with reference numerals corresponding to those of the first embodiment. In each of the above embodiments, the heating element 6 of the ceramic heater 6 is used.
The self-temperature control is performed by interposing a control coil 13 between one electrode (positive electrode) 4 and the electrode take-out fitting 12. In this embodiment, the control coil 13 is connected in series between the ceramic heater 6 and the electrode take-out fitting 12, and the structure of each of the above-mentioned embodiments fixed inside the metal outer cylinder 8 by swaging is used as it is. Thus, even when the resistance values of the individual ceramic heaters 6 are different, variations in the heat generation characteristics due to the resistance deviation can be reduced.

In this embodiment, as shown in the upper part of FIG. 12, different resistance values (R'1, R'2, R ') are previously determined.
.., R′n) are prepared in advance, and the resistance values (R1, R2, R
3,... Rn), a resistor 113 having an appropriate resistance value is selected from the plurality of resistors 113, and these resistors are connected in series.
13, the variation of the heat generation characteristics as a whole is made as small as possible. In this embodiment, the resistor 113 has a coil shape, and at one end, a connecting portion 113a to the positive electrode side of the heating element of the ceramic heater 6 is provided.
At the other end, a connection portion 113b for connecting to the electrode extraction fitting 12 is formed.

The ceramic heater 6 and the resistor 113
The ceramic glow plug 1 having the above structure can be assembled by the same process as that of the ceramic glow plug 1 of the first embodiment or by another process. For example, first, according to the resistance values (R1, R2, R3,..., Rn) of the ceramic heater 6, the ceramic heaters 6 have optimum resistance values (R′1, R′2, R′3,. The resistor 113 is selected, and one end 113a of the resistor 113 is selected.
Into the mounting hole 6c of the ceramic heater 6,
The heating element (not shown in FIG. 12) of the ceramic heater 6 is connected to the positive electrode by silver brazing, and the other end 113 b of the resistor 113 is welded to the rigid electrode extraction fitting 12 to form an assembly. The ceramic heater 6 as this assembly is inserted into the metal outer cylinder 8 and fixed by silver brazing.

Thereafter, the inside of the metal outer cylinder 8 is filled with the heat-resistant insulating powder 14, the sealing member 16 is inserted into the opening of the metal outer cylinder 8, and swaging is performed. The diameter of the heat-resistant insulating powder 14 is increased by reducing the outer diameter of 8, and the resistor 113 and the electrode extraction metal fitting 12 are fixed in the metal outer cylinder 8. Further, an external connection terminal 18 is fixed to an outer end 12b of the electrode extraction fitting 12. The subassembly including the ceramic heater 6, the metal outer cylinder 8, the resistor 113, the external connection terminal 18, and the like is fixed to the internal hole 4 of the housing 2.

As described above, the resistance values (R′1, R′2, R′3, R′3, R′3, R′3,
... By selecting one resistor 113 from among the resistors 113 having R′n) and connecting the resistor 113 in series with the ceramic heater 6, the variation in the heat generation characteristics due to the resistance deviation of the ceramic heater 6 is reduced. Can be. Therefore, the resistance values (R1, R2, R
3. In order to suppress the variation of Rn), conventionally, it was necessary to manufacture the ceramic heater 6 by a hot press method, but at a lower cost than the hot press method,
The ceramic heater 6 can be manufactured by a simple method.

In the case where the ceramic heater 6 is manufactured by the hot press method, the above-mentioned structure can reduce the cost by improving the yield of products and reducing the number of management items. In addition, the resistor 113 is connected in series between the positive electrode side of the ceramic heater 6 and the electrode take-out fitting 12 inside the metal outer cylinder 8, and these are simply integrated by swaging. The cost increase for the construction is very small.

FIG. 13 shows a part of an assembling process of the ceramic glow plug 1 according to the seventh embodiment. In the embodiment shown in FIG.
1, R'2, R'3,..., R'n) are prepared in advance, and a plurality of coiled resistors 113 are prepared. Although the selected resistors 113 are combined and connected in series, in this embodiment, a single resistor (control coil) 213 is used, and the connection position of the electrode extraction metal fitting 212 connected to the resistor 213 is used. Is adjusted to optimize the external resistance value.

The resistor 213 used in the ceramic glow plug 1 of this embodiment has a coiled portion 213e.
A heating element of ceramic heater 6 (not shown)
Has a connection end 213a connected to the positive electrode side of
The connection side to the other electrode extraction metal fitting 212 remains the coil-shaped portion 213e. On the other hand, a screw portion 212a is formed on the connection side of the electrode extraction metal fitting 212 to the resistor 213, and the screw portion 212a is screwed into the coil-shaped portion 213e of the resistor 213, thereby forming the resistor 2a.
13 and the electrode extraction fitting 212 are connected and electrically connected.

When assembling the ceramic glow plug 1, first, one end 213a of the resistor 213 is connected
Mounting hole 6c formed on the end face of ceramic heater 6
When the resistor 213 is connected to the positive electrode side of the heating element of the ceramics heater 6 by inserting the ceramic heater 6 into the small diameter portion 8f of the metal outer cylinder 8 and brazing it. At the same time, ceramic heater 6
And the metal outer cylinder 8 are joined. In this state, the resistance values of the ceramic heater 6 and the resistor 213 are measured (FIG. 13).
(A)).

Next, the screw 212a side of the electrode extraction fitting 212 is inserted through the opening of the metal outer cylinder 8 (FIG. 13).
(See the arrow in (b)).
3 is screwed into the coiled portion 213e. The external resistance value is optimized by adjusting the screwing position of the electrode extraction fitting 212 into the resistor 213 in accordance with the measured resistance value in FIG. 13A (see FIGS. 13C and 13D). After adjusting the screwing position of the electrode take-out fitting 212, the heat-resistant insulating powder 14 is filled through the opening of the metal outer cylinder 8, and the sealing member 16 is inserted into the opening (see FIG. 13 (e)). Swaging is performed (see FIG. 13 (f)). By reducing the diameter of the large-diameter portion 8g of the metal outer cylinder 8 by swaging, the heat-resistant insulating powder 14 is densified and the resistor 2
13 and the electrode extraction fitting 212 are fixed inside the metal outer cylinder 8.

Also in this embodiment, when the resistance values of the individual ceramic heaters 8 vary, the external resistance value can be optimized by adjusting the screwing position of the electrode extraction metal fitting 212. Unlike the conventional configuration, the ceramic heater 6 can be manufactured at a lower cost and by a simple method without using the hot press method. Also, when the ceramic heater 6 is manufactured by hot pressing, the above-described structure makes it possible to improve the yield of products and reduce costs by reducing management items. Moreover, in the metal outer cylinder 8, a resistor 21 is connected in series between the positive electrode side of the ceramic heater 6 and the electrode extraction metal fitting 212.
3, the cost increase for the structure of this embodiment is extremely small.

Further, since the electrode take-out fitting 212 is screwed into the coil portion 213e of the resistor 213 connected to the ceramic heater 6, they are connected to each other, so that the entire construction method can be automated. In addition, since the electrode extraction fitting 212 and the resistor 213 are connected inside the metal outer cylinder 8 by the insulator 14 which has been densified by swaging, the joining of these two 212 and 213 can be performed at an arbitrary position. Can be performed reliably. In the configuration of the first to fifth embodiments, the control coil is a self-control type ceramic glow plug, and has a larger positive temperature coefficient of resistance than the heating element of the ceramic heater.
It is connected between the ceramic heater and the electrode takeout. On the other hand, in the configurations of the sixth and seventh embodiments, when the manufactured ceramic heaters have different resistance values, another resistor is connected in series to connect these ceramic heaters. The purpose of the present invention is to adjust the variation of the resistance value of each ceramic heater so that the resistance value as a whole with the resistor is substantially the same, and satisfy the requirements as the control coil. No need.

[0086]

As described above, according to the first aspect of the present invention, a ceramics heater formed of insulating ceramics and an inorganic conductor, and the ceramics heater is fixed in one end portion and the other end portion. A metal outer cylinder whose side is fixed to the internal hole of the housing, a control coil connected to one pole of the heating element and having a larger positive temperature coefficient of resistance than the heating element, and the other end of the control coil. In a self-control type ceramic glow plug including a connected electrode extraction metal fitting, the electrode extraction metal fitting is formed of a rigid body, and the control coil and a connecting portion between the control coil and the electrode extraction metal fitting are formed of the metal outer cylinder. The control coil is housed in a metal outer cylinder, and the control coil is fixed to the metal outer cylinder via an insulator. Since it integrated with mix heater, the assembly is easy, the cost can be reduced. Further, since the structure is similar to that of the conventional self-control type metal glow plug, the assembly equipment can be shared.

According to the second aspect of the present invention, the insulator is a heat-resistant insulating powder filled in a metal outer cylinder and densified by swaging. Since the control coil is fixed in the metal outer cylinder via the heat-resistant insulating powder thus obtained, the durability of the control coil can be improved. Further, it is easy to keep the control coil portion airtight.

According to the fourth aspect of the present invention, since the control coil is disposed inside the front end of the housing, the size of the ceramic heater can be reduced, and the overall cost can be reduced. be able to. Further, since the distance between the heating element of the ceramic heater and the control coil can be increased, the temperature controllability can be improved.

According to the fifth to ninth aspects of the present invention, the electrical connection between the control coil and the electrode fitting can be easily ensured.

Further, according to the tenth aspect of the present invention, a ceramics heater formed of insulating ceramics and an inorganic conductor as a heating element, the ceramics heater is fixed in one end, and the other end is A ceramic glow plug including a metal outer cylinder fixed to an inner hole of a housing, a resistor connected to one pole of the heating element, and an electrode extraction fitting connected to the other end of the resistor. According to the resistance value of the ceramic heater, by combining resistors having different resistance values and connecting them in series, the resistance value of the ceramic heater is corrected to make the overall heat generation characteristics substantially the same. Variations in heat generation characteristics due to individual resistance deviations of heaters can be reduced. It is possible to produce Kkusuhita, also in the case of hot pressing, the like to improve the yield of the product, reduce management items,
Cost reduction becomes possible.

According to the eleventh aspect of the present invention, the electrode extraction metal fitting side of the resistor is formed in a coil shape, and a screw portion is formed at the tip of the electrode extraction metal fitting. By screwing into the shaped part, the resistor and the electrode extraction metal fitting are connected, and
The screwing position of the electrode extraction bracket is configured to be adjustable,
The resistance value of the ceramic heater is corrected by measuring the resistance value of the ceramic heater and the resistor connected in series and adjusting the screwing position of the electrode take-out fitting in accordance with the measured value. Are substantially the same, the same effects as those of the invention described in claim 10 can be obtained, and the entire construction method can be automated.

According to the manufacturing method according to the thirteenth to fifteenth aspects of the present invention, the self-control type ceramic glow plug can be easily manufactured.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a self-control ceramic glow plug according to an embodiment of the present invention.

FIG. 2 is an enlarged longitudinal sectional view showing a main part of the self-control type ceramic glow plug.

FIG. 3 is a view showing a procedure for assembling the self-control type ceramic glow plug, showing a first half thereof.

FIG. 4 is a view showing a procedure for assembling the self-control type ceramic glow plug, showing a latter half thereof.

FIG. 5 is a view showing a procedure for assembling the self-control type ceramic glow plug, and shows a sub-assembly in the middle of the assembly.

FIG. 6 is a view showing an assembling procedure of the self-control type ceramic glow plug according to the second embodiment, showing a first half thereof.

FIG. 7 is a view showing an assembling procedure of the self-control ceramic glow plug according to the second embodiment, and shows a latter half thereof.

FIG. 8 is a view showing a procedure for assembling the self-control type ceramic glow plug, showing a sub-assembly in the middle of the assembly.

FIG. 9 is a view showing an assembling procedure of the self-control type ceramic glow plug according to the third embodiment, and shows a first half thereof.

FIG. 10 is a view showing a procedure for assembling a self-controlling ceramic glow plug according to a fourth embodiment, showing a first half thereof.

FIG. 11 is a longitudinal sectional view showing the overall configuration of a self-controlling ceramic glow plug according to a fifth embodiment.

FIG. 12 is a diagram illustrating a combination of a ceramics heater and a resistor of a ceramics glow plug according to a sixth embodiment.

FIG. 13 is a view showing a procedure for assembling the ceramic glow plug according to the seventh embodiment, showing a first half thereof.

[Explanation of symbols]

 2 Housing 2a Housing tip 4 Housing inner hole 6 Ceramic heater 8 Metal outer cylinder 8f Small diameter section of metal outer cylinder 8g Large diameter section of metal outer cylinder 11 Lead wire (positive electrode lead wire) 12 Electrode extraction fitting 13 Control Coil 14 Insulator (Heat-Resistant Insulating Powder) 62 Insulating Ceramics 64 Heating Element (Coiled Heating Wire)

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Aota 3--13-26 Yayumicho, Higashimatsuyama-shi, Saitama Prefecture Bosch Automotive System Higashimatsuyama Factory (72) Inventor Zhao Zhao Zhao 3-chome, Yayumicho, Higashimatsuyama-shi, Saitama 13-26 Bosch Automotive System Co., Ltd. Higashi-Matsuyama Plant (72) Inventor Shunji Miura 3-13-26 Yaumicho, Higashi-Matsuyama City, Saitama Prefecture Bosch Automotive System Higashi-Matsuyama Plant

Claims (15)

[Claims] 1. A ceramic heater formed of insulative ceramics and an inorganic conductor as a heating element, and a metal heater having the ceramic heater fixed in one end and the other end fixed to an internal hole of a housing. Self-control comprising a cylinder, a control coil connected to one pole of the heating element and having a larger positive temperature coefficient of resistance than the heating element, and an electrode extraction metal fitting connected to the other end of the control coil. In the ceramic glow plug of the type, while forming the electrode take-out fitting with a rigid body,
The control coil and a connecting portion between the control coil and the electrode take-out fitting are accommodated in the metal outer cylinder, and the control coil and the electrode take-out fitting are fixed to the metal outer casing through an insulator. Self-control type ceramic glow plug. 2. The self-controlling ceramic glow plug according to claim 1, wherein the insulator is a heat-resistant insulating powder filled in a metal outer cylinder and densified by swaging. A self-controlling ceramic glow plug characterized by the following characteristics: 3. The self-controlling ceramic glow plug according to claim 1, wherein the metal outer cylinder is connected to a small-diameter portion to which the ceramic heater is fixed and a large-diameter portion to be fixed to the housing. A self-control type ceramic glow plug, wherein the control coil is disposed in a large diameter portion. 4. The self-control type ceramic glow plug according to claim 1, wherein said control coil is disposed inside a front end portion of said housing. Ceramic glow plug. 5. The self-control type ceramic glow plug according to claim 1, wherein one of the poles of the ceramic heater and a control coil are connected via a lead wire. Self-control type ceramic glow plug. 6. The self-controlling ceramic glow plug according to claim 1, wherein an insertion hole is formed in the electrode extraction metal fitting at an end face thereof, and the electrode extraction metal fitting has an opening formed in the insertion hole. A self-control type ceramic glow plug, wherein one end of a control coil is inserted and connected. 7. The self-controlling ceramic glow plug according to claim 6, wherein the insertion hole is a through hole that penetrates the electrode fitting in the axial direction, and the control coil is inserted through the through hole. A self-control type ceramic glow plug, wherein the connection with the control coil is performed by plastically deforming the outer periphery of the electrode extraction metal fitting. 8. The self-control type ceramic glow plug according to claim 1, wherein a tip side face of said control coil is in contact with a tip side face of said electrode takeout fitting. Self-controlling ceramic glow plug characterized by: 9. The self-control type ceramic glow plug according to claim 1, wherein a tip portion of said control coil is formed in a coil shape, and said coil-shaped portion is provided with said electrode extraction fitting. A self-controlling ceramic glow plug characterized in that the tip is inserted and connected. 10. A ceramic heater formed of insulating ceramics and an inorganic conductor as a heating element, and a metal heater having the ceramic heater fixed in one end and the other end fixed to an internal hole of the housing. A tube,
In a ceramic glow plug including a resistor connected to one pole of the heating element and an electrode extraction fitting connected to the other end of the resistor, different resistance values are provided according to the resistance value of the ceramic heater. A ceramic glow plug characterized in that the resistance value of a ceramic heater is corrected by combining resistors in series and connected in series to make the overall heat generation characteristics substantially the same. 11. A ceramic heater formed of insulative ceramics and an inorganic conductor as a heating element, and a metal heater having the ceramic heater fixed in one end and the other end fixed to an internal hole of the housing. A tube,
In a ceramic glow plug including a resistor connected to one pole of the heating element and an electrode extraction fitting connected to the other end of the resistor, the electrode extraction fitting side of the resistor is formed in a coil shape. At the same time, a screw portion is formed at the tip of the electrode extraction metal fitting, and the screw portion is screwed into the coil-shaped portion, thereby connecting the resistor and the electrode extraction metal fitting, and adjusting the screwing position of the electrode extraction metal fitting. The resistance value of the ceramic heater is corrected by measuring the resistance value of the ceramic heater and the resistor connected in series and adjusting the screwing position of the electrode extraction metal fitting according to the measured value. A ceramic glow plug characterized by having substantially the same overall heat generation characteristics. 12. The ceramic glow plug according to claim 10 or 11, wherein the metal fitting is formed of a rigid body.
The resistor and the connection portion between the resistor and the electrode take-out fitting are accommodated in the metal outer cylinder, and these resistors and the electrode take-out fitting are made of heat-resistant insulating powder that has been densified by swaging. A ceramic glow plug fixed to the metal outer cylinder via 13. A method for manufacturing a self-control type ceramic glow plug according to claim 1, wherein one end of said control coil is connected to one end of an electrode extraction fitting made of a rigid body. Connecting the other end of the control coil to one pole of the ceramic heater, fixing the ceramic heater in the metal outer cylinder, and connecting the heat-resistant insulating powder through an opening of the metal outer cylinder. Step of filling the body, by reducing the outer peripheral portion of the metal outer cylinder in which the connection portion of the control coil and the electrode extraction fitting is housed by swaging,
Fixing the control coil and the electrode take-out fitting to the metal outer cylinder in this order. 14. The method for manufacturing a ceramic glow plug according to claim 1, wherein one end of the control coil is connected to one pole of a ceramic heater, and the ceramic heater is connected to a metal. A step of fixing to one end of the outer cylinder made of metal; a step of connecting the other end of the control coil to one end of the electrode extraction metal fitting; a step of filling a heat-resistant insulating powder from an opening of the outer cylinder made of metal; The outer peripheral portion of the metal outer cylinder, in which the connection portion between the control coil and the electrode extraction metal fitting is accommodated, is reduced in diameter by swaging to fix the control coil and the electrode extraction metal fitting to the metal outer cylinder. And a step of sequentially performing the steps. 15. The method for manufacturing a ceramic glow plug according to claim 13, wherein the metal outer cylinder has a small diameter at a portion to which the ceramic heater is fixed, and a control coil and the control coil and an electrode. A method for producing a self-controlling ceramic glow plug, characterized in that a portion where a connection portion with a take-out fitting is inserted has a large diameter, and the large diameter portion is reduced in diameter by swaging.