JP2020176787A - Ceramic heater type glow plug and its manufacturing method - Google Patents

Abstract

To provide a ceramic heater type glow plug which can obtain a holding structure for holding a lead wire withdrawn from an end face of a ceramic heater and a housing of an electrode withdrawal metal fitting connected to the lead wire by a simple structure and at a low cost.SOLUTION: A ceramic heater type glow plug comprises: a ceramic heater 6; a metal-made outer cylinder 8 in which the ceramic heater 6 is fixed into one end part 8a, and the other end part 8b or its vicinity is fixed into an internal hole 4 of a housing 2; an electrode withdrawal metal fitting 12 whose one end part 12a is connected to an end part of a lead wire 10 protruding from an end face 6b of the ceramic heater 6 located in the metal-made outer cylinder 8, and which is formed of a rod-shaped rigid body; and an insulator 14 located at a connecting part between the electrode withdrawal metal fitting 12 and the lead wire 10, having a penetration hole which the lead wire 10 penetrates, and at least partially fitting to the other end part 8b of the metal-made outer cylinder 8. A manufacturing method of the ceramic heater type glow plug is also provided.SELECTED DRAWING: Figure 1

Description

The present invention relates to a ceramic heater type glow plug for assisting in starting a diesel engine and a method for manufacturing the same, using a ceramic heater as a heating element.

As a ceramic heater, a coil of a refractory metal (for example, tungsten, etc.), a heating element of conductive ceramics, or a film-shaped heating element is embedded in insulating ceramics, or a part of the heating element of conductive ceramics is embedded. After exposing, the lead wire on the negative electrode side of the heating element is taken out from the side surface of the insulating ceramics and connected to the metal outer cylinder, and the lead wire on the positive electrode side is taken out from the end face on the side far from the heating element of the insulating ceramics. , A structure is conventionally known in which one end of the electrode take-out metal fitting is connected and an external connection terminal is connected to the other end of the electrode take-out metal fitting.

In recent years, in order to comply with exhaust gas regulations, the direct injection type of diesel engines has been attempted, and in order to comply with this, it is required to reduce the diameter and length of the glow plug. In order to meet such demands, when assembling, the diameter of the member passing through the housing is reduced to reduce the diameter of the housing while ensuring the strength of the housing, and when connecting the battery terminal to the external connection terminal. It is desired to secure the tightening torque and the strength to withstand the vibration of the engine.

In the case of a sheath type heater that has been widely used as a heating element for glow plugs for diesel engines, the electrode take-out bracket is fixed in the sheath by aging processing, so this electrode take-out bracket can be used to connect to the external connection terminal. The strength against tightening torque and engine vibration is ensured. On the other hand, in the ceramic heater, there is a problem that it is difficult to secure the strength because the lead wire taken out from the end face thereof is thin.

A technique for solving this problem is disclosed in Patent Document 1. That is, the technique described in Patent Document 1 is a metal outer cylinder in which a lead wire taken out from the end face of a ceramic heater and a holding structure for a housing of an electrode take-out metal fitting connected to the lead wire are housed. The space is filled with heat-resistant insulating powder such as magnesium oxide powder, the opening of the metal outer cylinder is sealed with a rubber sealing member, and then the outer diameter of the metal outer cylinder where these are housed. It is realized by performing aging processing to reduce the diameter. According to the technique described in Patent Document 1, sufficient strength can be ensured against tightening torque for external connection terminals and engine vibration.

However, in the technique described in Patent Document 1, the work process is complicated and the maintenance cost is high due to the fixing of the connection lead from the ceramic heater and the electrode take-out metal fitting to the housing with the heat-resistant insulating powder and the aging process. Invited to change.

JP-A-2002-195559

Therefore, the present invention has been made in view of the above problems, and one of the purposes thereof is to hold the lead wire taken out from the end face of the ceramic heater and the housing of the electrode take-out metal fitting connected to the lead wire. The purpose is to provide a ceramic heater type glow plug that can be realized with a simple structure and at low cost. Another object of the present invention is to provide a method for manufacturing a ceramic heater type glow plug that can be manufactured by a simple process.

The above problem is solved by the following invention. That is, the ceramic heater type glow plug of the present invention includes a heating element made of an inorganic conductor and a ceramic heater made of insulating ceramics.
A metal outer cylinder in which the ceramic heater is fixed in one end and the other end or its vicinity is fixed in the inner hole of the housing.
An electrode taken out of a rod-shaped rigid body, one end of which is connected to the end of a lead wire connected to the heating element, which protrudes from the end face of the ceramic heater located in the metal outer cylinder. With metal fittings
An insulator located at a connection portion between the electrode take-out metal fitting and the lead wire, having a through hole through which the lead wire penetrates, and at least partially fitting into the other end of the metal outer cylinder.
It is characterized by being equipped with.

In the present invention, it is preferable that a recess in which the one end of the electrode take-out metal fitting is fitted is formed on the side of the insulator opposite to the side where the metal outer cylinder is fitted.
In this case, it is preferable that the tip of the one end of the electrode take-out metal fitting is in contact with the bottom of the recess in the recess to be fitted.

Further, in the present invention, between the small diameter portion in which the insulator fits into the other end of the metal outer cylinder, the large diameter portion having a larger diameter than the small diameter portion, and the large diameter portion and the small diameter portion. It is preferable to have a step portion that connects the metal outer cylinders and abuts the opening end at the other end portion of the metal outer cylinder.
In this case, the small diameter portion is provided with a rib having an inclined portion whose height gradually increases from the tip end side of the small diameter portion toward the step portion over the entire area in the fitting direction or a part thereof. It is preferable to have.

Further, in the present invention, an insertion hole is formed in the end surface of the one end of the electrode take-out metal fitting.
It is preferable that the electrode take-out metal fitting and the lead wire are connected by inserting the end portion of the lead wire into the insertion hole.

In this case, the insertion hole extends in the axial direction of the electrode take-out metal fitting.
At the axial position where the lead wire inserted into the insertion hole exists, and at the axial position where the insulator does not exist, the outer circumference of the electrode take-out fitting may have a reduced diameter portion. preferable.

On the other hand, the first manufacturing method of the ceramic heater type glow plug of the present invention is the manufacturing method for manufacturing the ceramic heater type glow plug of the present invention.
A metal outer cylinder mounting step of inserting and fixing the ceramic heater into the metal outer cylinder so that the end portion from which the lead wire protrudes is located inside and the lead wire penetrates and is exposed.
An insulator mounting step in which at least a part of the insulator is fitted into the other end of the metal outer cylinder while the lead wire is passed through the through hole.
An electrode take-out metal fitting attachment step of connecting the one end of the electrode take-out metal fitting and the end of the lead wire to position the insulator at the connection part.
A housing mounting step of fixing the other end of the metal outer cylinder to the end opening of the internal hole so that the connection portion is located in the internal hole of the housing.
Is characterized in this order.

Further, the second manufacturing method of the ceramic heater type glow plug of the present invention is the manufacturing method for manufacturing the ceramic heater type glow plug of the present invention.
A metal outer cylinder mounting step of inserting and fixing the ceramic heater into the metal outer cylinder so that the end portion from which the lead wire protrudes is located inside and the lead wire penetrates and is exposed.
An insulator temporary fixing step of temporarily fixing the side of the insulator opposite to the side to be fitted into the metal outer cylinder to the one end of the electrode take-out metal fitting.
The other end of the metal outer cylinder to which the ceramic heater is fixed is brought closer to the side of the insulator temporarily fixed to the electrode take-out metal fitting to be fitted into the metal outer cylinder, and the lead is inserted into the through hole. While penetrating the wire, at least a part of the metal outer cylinder is fitted into the other end, and at the same time, the one end of the electrode take-out metal fitting and the end of the lead wire are connected to each other. A four-component integration process that positions the insulator in the unit,
A housing mounting step of fixing the other end of the metal outer cylinder to the end opening of the internal hole so that the connection portion is located in the internal hole of the housing.
The feature is that the steps are performed in this order after the four-part integration process.

In either of the first manufacturing method and the second manufacturing method, an insertion hole is opened in the end face of the one end of the electrode take-out metal fitting and extends in the axial direction of the electrode take-out metal fitting. Is formed,
The connection between the electrode take-out metal fitting and the lead wire is made by inserting the end portion of the lead wire into the insertion hole.
Prior to the housing mounting step, the outer circumference of the electrode take-out metal fitting is reduced in diameter at the axial position where the lead wire inserted into the insertion hole exists and at the axial position where the insulator does not exist. It is preferable to have a lead wire binding step for binding the electrode take-out metal fitting and the lead wire.

According to the present invention relating to the ceramic heater type glow plug, the lead wire taken out from the end face of the ceramic heater and the holding structure for the housing of the electrode take-out metal fitting connected to the lead wire can be held by a simple structure and at low cost. Can be realized with.
Further, according to the present invention relating to the method for manufacturing a ceramic heater type glow plug, the ceramic heater type glow plug can be manufactured by a simple process.

It is a vertical sectional view of the ceramic heater type glow plug which concerns on embodiment which is an exemplary aspect of this invention. FIG. 5 is an enlarged cross-sectional view showing an enlarged view of a connection portion between a lead wire and an electrode take-out metal fitting in the ceramic heater type glow plug shown in FIG. 1 and its periphery. It is an enlarged perspective view which looked at the insulator in the ceramic heater type glow plug shown in FIG. 1 from a certain direction. It is an enlarged perspective view which looked at the insulator in the ceramic heater type glow plug shown in FIG. 1 from the direction different from FIG. It is a schematic cross-sectional view which shows the manufacturing process in the order of (a)-(e) when each step in the manufacturing method of the ceramic heater type glow plug of this invention is performed in order. It is a schematic cross-sectional view which shows the manufacturing process in the order of (a)-(e) when the operation is performed in order following each step in the other manufacturing method of the ceramic heater type glow plug of this invention.

[Ceramic heater type glow plug]
Hereinafter, embodiments of the ceramic heater type glow plug of the present invention will be described with reference to the drawings. FIG. 1 is a vertical sectional view of a ceramic heater type glow plug according to an embodiment which is an exemplary embodiment of the present invention. Further, FIG. 2 shows a connection portion between the lead wire 10 protruding from the end face of the heating element in the ceramic heater and the electrode take-out metal fitting 12 of the ceramic heater type glow plug according to the embodiment according to the embodiment of the present invention. It is an enlarged cross-sectional view which shows the periphery enlarged.

The housing 2 of this ceramic heater type glow plug (hereinafter, may be simply referred to as “glow plug”) has a cylindrical shape, and the hole (internal hole 4) inside the housing 2 is fixed to the ceramic heater on the right side of the drawing. The side is the large diameter portion 4a, and the side fixed to the external connection terminal on the left side of the figure is the small diameter portion 4b, which is a stepped hole extending in the axial direction.

A metal outer cylinder 8 to which the ceramic heater 6 is joined by press fitting or brazing is inserted into the large diameter portion 4a of the inner hole 4 of the housing 2, and a part of the outer peripheral surface of the metal outer cylinder 8 is formed. It is fixed to the end opening 2a of the housing 2 by press fitting or brazing. That is, the ceramic heater 6 is fixed in the tip (one end) 8a of the metal outer cylinder 8, and the vicinity of the rear end (other end) 8b is in the end opening 2a of the internal hole 4 of the housing 2. It is fixed.

The ceramic heater 6 has a conventionally known configuration, and although the illustration and detailed description of the inside are omitted, a refractory metal (for example, tungsten (W)) is coiled inside the ceramic insulator constituting the main body thereof. It has a heat generating portion 6a in which a shaped heating wire (heating body) is embedded, and the heating portion 6a protrudes from the tip (one end) 8a of the metal outer cylinder 8 and the heat generating portion 6a. The end surface 6b on the side far from the metal outer cylinder 8 is located inside the metal outer cylinder 8.

In this embodiment, the heating element is a refractory metal, but it may be a conductive ceramic or a sheet-shaped heating element, and a part of the heating element of the conductive ceramic is exposed from the insulating ceramic. As the ceramic heater 6, a ceramic heater 6 formed by combining an insulating ceramic and an inorganic conductor as a heating element is used.

A lead wire on the negative electrode side is connected to one end of a coiled heating wire embedded inside the ceramic heater 6, and a lead wire on the positive electrode side is connected to the other end. The lead wire on the negative electrode side is exposed on the outer surface of the ceramic insulator on the inner side of the metal outer cylinder 8 and is electrically connected to the inner surface of the metal outer cylinder 8 by brazing or the like.

The metal outer cylinder 8 is formed of a conductive metal material, for example, a material of stainless steel (SUS430 or the like). The outer peripheral surface of the metal outer cylinder 8 is formed in a stepped cylindrical shape. In particular, in the present embodiment, as will be described later, it is not necessary to perform special processing for holding the insulator 14 on the inner peripheral surface, and a tube shape having only a cylindrical inner peripheral surface is sufficient. It can be easily produced by the stretching method. Therefore, the metal outer cylinder 8 in the present embodiment can be formed at low cost.

The lead wire on the positive electrode side of the heating wire inside the ceramic heater 6 extends to the end surface 6b side of the ceramic heater 6, and is connected to the lead wire 10 for taking out the electrode in the ceramic heater 6. The lead wire 10 for taking out the electrode is a wire rod having a small diameter. The lead wire 10 for taking out the electrode protrudes from the end surface 6b side of the ceramic heater 6 and further extends, and the end portion 10a protrudes from the rear end (other end portion) 8b of the metal outer cylinder 8.

The structure in which the lead wire 10 for taking out the electrode is connected to the lead wire on the positive electrode side inside the ceramic insulator and taken out to the outside of the ceramic heater is described in JP-A-2000-121055, JP-A-2001-324141 and the like. The method given, or any other method, can be applied.

The lead wire 10 for taking out the electrode taken out from the end surface 6b of the ceramic heater 6 extends through the through hole 14a provided in the center of the insulator 14. FIG. 3 shows an enlarged perspective view of the insulator 14 viewed from a certain direction, and FIG. 4 shows an enlarged perspective view of the insulator 14 viewed from another direction.

The insulator 14 includes a small diameter portion 14b that fits into the rear end (other end) 8b of the metal outer cylinder 8, a large diameter portion 14c that has a larger diameter than the small diameter portion 14b, and a large diameter portion 14c and a small diameter portion 14b. It has a step portion 14d and a step portion 14d for connecting the spaces. The step portion 14d is an annular portion having the same outer diameter as the large diameter portion 14c and the inner diameter portion 14b.

The small diameter portion 14b has a height (in the present invention, ribs) in a part of the fitting direction (arrow A direction in FIG. 3) from the tip end side (arrow A direction side) of the small diameter portion 14b toward the step portion 14d. The height of the small diameter portion 14b refers to the height from the peripheral surface of the small diameter portion 14b), and the rib 14f having the inclined portion 14e is provided. In the rib 14f, the step portion 14d side following the inclined portion 14e has an equal height portion 14g having a constant height.

In the present invention, when the rib (14f) is provided on the small diameter portion 14b of the insulator 14, the length of the rib (14f) itself is from the tip side (arrow A direction side) in the fitting direction (arrow A direction). It may cover the entire area of the step portion 14d, or it may start from the middle as in the present embodiment. Further, the rib (14f) does not have to reach the step portion 14d. The width (peripheral length of the small diameter portion 14b) and the number of ribs are not particularly limited and may be appropriately designed.

Further, the length of the inclined portion 14e may extend from the tip end side (arrow A direction side) in the fitting direction (arrow A direction) to the entire length of the rib (14f) of the step portion 14d, as in the present embodiment. It may be a part of the rib (14f). By providing the rib (14f), press fitting into the metal outer cylinder 8 described later may be preferably performed.

A recess 14h into which the tip end portion (one end portion) 12a of the electrode extraction metal fitting 12 is fitted is formed on the side of the insulator 14 opposite to the side to be fitted into the metal outer cylinder 8 (the side opposite to the direction of arrow A). Has been done. Further, the insulator 14 is formed with a through hole 14a that is parallel to the central axis that penetrates the insulator 14 in the fitting direction (arrow A direction) and includes the insulator 14.

The through hole 14a is a hole that extends so as to coincide with the central axis of the metal outer cylinder 8 and penetrates between the side of the insulator 14 that fits into the metal outer cylinder 8 and the opposite side. .. The lead wire 10 is supported at the position of the central axis of the metal outer cylinder 8 by being held through the through hole 14a.

The insulator 14 is located at a connection portion between the electrode take-out metal fitting 12 and the lead wire 10, and a small diameter portion 14b, which is a part thereof, is fitted into the rear end 8b of the metal outer cylinder 8. Then, the lead wire 10 penetrates through the through hole 14a, and the small diameter portion 14b is fitted into the rear end 8b of the metal outer cylinder 8. In this state, the step portion 14d is in contact with the opening end 8c at the rear end 8b of the metal outer cylinder 8. Since the step portion 14d is in contact with the opening end 8c of the rear end 8b, positioning is performed between the insulator 14 and the metal outer cylinder 8, and the positional relationship between the two becomes stable.

The material of the insulator 14 is not particularly limited, but is preferably made of resin because it has a shape suitable for resin molding and can be molded at low cost. The insulator 14 having the shape shown in the present embodiment can be easily molded by a known resin molding method. Further, since the metal outer cylinder 8 is interposed and separated to some extent without being in direct contact with the ceramic heater 6, and the required heat resistance is not so high, there are relatively few restrictions on the resins that can be selected. .. Specific examples of the selectable resin include fluororesin, polyamide resin (nylon), polyetheretherketone (PEEK) resin, and the like.

The tip portion 12a of the electrode take-out metal fitting 12 is fitted in the recess 14h of the insulator 14. The end surface 12b of the tip portion 12a of the electrode take-out metal fitting 12 is in contact with the bottom 14i of the recess 14h to be fitted. Since the end surface 12b is in contact with the bottom 14i, positioning is performed between the electrode take-out metal fitting 12 and the insulator 14, and further between the metal outer cylinder 8 into which a part of the insulator 14 is fitted. , The positional relationship between the three parties becomes stable.

The electrode take-out metal fitting 12 is formed of a rod-shaped rigid body, and an insertion hole 12f is formed in the end surface 12b of the tip portion 12a thereof so as to open toward the end face 12b and extend in the axial direction of the electrode take-out metal fitting 12. Has been done. Then, by inserting the end portion 10a of the lead wire 10 into the insertion hole 12f, the electrode take-out metal fitting 12 and the lead wire 10 are electrically connected.

The connection between the electrode take-out metal fitting 12 and the lead wire 10 is generally made by press-fitting or brazing the end portion 10a of the lead wire 10 into the insertion hole 12f, or by crimping the tip end portion 12a of the electrode take-out metal fitting 12. Allows for certainty. However, in the present embodiment, the outer circumference of the electrode take-out metal fitting 12 at the axial position where the lead wire 10 exists and at the axial position where the insulator 14 does not exist is reduced in diameter to become the reduced diameter portion 12c. The electrode take-out metal fitting 12 and the lead wire 10 are tightly connected at each location.

By narrowing the outer circumference of the electrode take-out metal fitting 12 so as to tighten it from the radial direction, the diameter-reduced portion 12c can be formed. When the electrode take-out metal fitting is plastically deformed from the outside of the metal outer cylinder via the heat-resistant insulating powder to be fixed in the sheath and at the same time the lead wire is connected as in the aging process described in Patent Document 1. Since the pressure is indirectly applied, the effect of improving the connection strength between the electrode take-out metal fitting and the lead wire is not so high, but in the present embodiment, the outer circumference of the electrode take-out metal fitting 12 is directly squeezed, so that it is a simple method. However, the connection between the electrode take-out metal fitting 12 and the lead wire 10 can be made extremely strong.

The electrode take-out metal fitting 12 extends coaxially within the small diameter portion 4b of the internal hole 4 of the housing 2, and the rear end portion 12d, which is the end opposite to the front end portion 12a, protrudes to the outside of the housing 2. .. An insulator 12g different from the insulator 14 is attached to a portion of the electrode take-out metal fitting 12 in the small diameter portion 4b near the rear end portion 12d.

The insulator 12g is interposed between the inner peripheral surface of the internal hole 4 of the housing 2 and the electrode take-out metal fitting 12, and functions as an insulating spacer between the two, and also functions as a support member for the electrode take-out metal fitting 12. The electrode take-out metal fitting 12 is supported by the insulator 12g on the rear end 12d side, and is supported by the insulator 14 (further, the metal outer cylinder 8) on the tip 12a side as described above, and is an internal hole of the housing 2. Within 4, the distance from the inner peripheral surface thereof is maintained, and the insulation between the two is ensured.

A seal member (O-ring) 20 is inserted into the rear end portion 12d of the electrode take-out metal fitting 12, and the end opening 2a of the small diameter portion 4b of the internal hole 4 of the housing 2 is fitted. The end opening 2a is an annular portion formed with a taper, and a seal member 20 having a corresponding shape is brought into contact with the seal member 20 to be fitted.

A knurled portion 12e having a knurled peripheral surface is formed in the vicinity of the rear end portion 12d protruding from the housing 2 of the electrode take-out metal fitting 12. The knurled portion 12e is fitted into the hole of the insulating and annular insulator 26. Then, the rear end portion 12d of the electrode take-out metal fitting 12 is fitted into the hole of the round pin 18, and the outer circumference of the round pin 18 is reduced in diameter at the position where the knurled portion 12e is formed. It is fixed to 18, and the electrode take-out metal fitting 12 is fixed to the housing 2 with the insulator 26 and the seal member 20 interposed therebetween.

According to the ceramic heater type glow plug of the present embodiment as described above, the lead wire 10 taken out from the end surface 6b of the ceramic heater 6 and the electrode take-out metal fitting 12 connected to the lead wire 10 can be easily molded. With a simple structure that uses only one insulator 14, it can be held against the housing 2, and cost reduction can be realized. Other manufacturing merits will be described in <Ceramics heater type glow plug manufacturing method> described below.

[Manufacturing method of ceramic heater type glow plug]
The ceramic heater type glow plug of the present invention can be suitably manufactured by the two types of manufacturing methods of the ceramic heater type glow plug of the present invention described below. Hereinafter, these two types will be referred to as "first manufacturing method" and "second manufacturing method", respectively. )

<First manufacturing method>
The first manufacturing method is a manufacturing method in which a metal outer cylinder mounting process, an insulator mounting process, an electrode taking-out metal fitting mounting process, and a housing mounting process are performed in this order, and the electrode taking-out metal fitting mounting process and housing mounting are performed in this order. If necessary, a lead wire binding step is included between the steps.
Hereinafter, each step will be described step by step with reference to FIG. Note that FIG. 5 is a schematic cross-sectional view showing the manufacturing process in the order of (a) to (e) when the operations are performed in order following each step in the first manufacturing method.

(Metal outer cylinder mounting process)
In the first manufacturing method, in the metal outer cylinder mounting step, as shown in FIG. 5A, the end face 6b from which the lead wire 10 protrudes is located inside the ceramic heater 6, and the lead wire 10 penetrates the ceramic heater 6. This is a step of fixing the metal outer cylinder 8 to the ceramic heater 6 by performing an operation of inserting the metal outer cylinder 8 so as to be exposed.

At this time, as shown in FIG. 5A, while holding the ceramic heater 6 vertically, the ceramic heater 6 is lowered from above so as to be inserted into the metal outer cylinder 8, and the ceramics are inserted into the metal outer cylinder 8. Insert the heater 6. The ceramic heater 6 is held vertically in all subsequent steps.

The ceramic heater 6 and the metal outer cylinder 8 may be fixed by press fitting, but as described above, the lead wire on the negative electrode side is exposed on the outer surface of the ceramic heater 6 on the inner side of the metal outer cylinder 8. Therefore, it is preferable to perform brazing with silver wax in order to ensure continuity. The electrical connection between the two can be realized by various other known methods. For example, the metallizing process described in Japanese Patent Application Laid-Open No. 2001-43960 is performed to ensure the continuity between the metallized layer and the silver wax. It is also possible to adopt a smoothing method.

(Insulator mounting process)
In the first manufacturing method, in the insulator mounting step, as shown in FIG. 5B, the insulator 14 is moved from above to below (in the direction of arrow B), and the lead wire 10 is inserted into the through hole 14a. In the step of inserting at least a part (in this example, a small diameter portion 14b corresponding to a part of the insulator 14) into the rear end (the other end) 8b of the metal outer cylinder 8 while penetrating this. is there.

That is, in this step, the small diameter portion 14b of the insulator 14 is fitted into the rear end 8b located above the metal outer cylinder 8 attached to the upper part of the ceramic heater 6 in the previous step. At this time, the tip of the lead wire 10 inserted into the through hole 14a is in a state of protruding from above.
The lead wire 10 penetrates through the through hole 14a whose axis coincides with the central axis of the metal outer cylinder 8 and is held so as to be supported at the position of the central axis of the metal outer cylinder 8. ..

As described above, the small diameter portion 14b of the insulator 14 is provided with the rib 14f, so that the small diameter portion 14b is lightly press-fitted into the opening of the rear end 8b of the metal outer cylinder 8. Therefore, it is smoothly press-fitted, and after fitting, it becomes a stable temporary fixing state. The relationship between the opening (inner diameter) of the rear end 8b of the metal outer cylinder 8 and the small diameter portion 14b of the insulator 14 (outer diameter including the overhang of the rib 14f) is such that light press fitting is performed as in the present embodiment. Suitable. However, in the first manufacturing method, the relationship between the two is not completely fitted, and the small diameter portion 14b is smaller than the opening of the rear end 8b and has some margin, and is compared to the opening of the rear end 8b. The small diameter portion 14b may be large and may not be fitted unless it is press-fitted strongly to some extent.

When the small diameter portion 14b of the insulator 14 is lightly press-fitted into the rear end 8b of the metal outer cylinder 8, the step portion 14d of the insulator 14 comes into contact with the opening end 8c of the rear end 8b of the metal outer cylinder 8. When the step portion 14d comes into contact with the opening end 8c of the rear end 8b, positioning (temporary fixing) is performed between the insulator 14 and the metal outer cylinder 8, and the positional relationship between the two becomes stable.

(Electrode extraction bracket mounting process)
In the first manufacturing method, in the electrode take-out metal fitting mounting step, an operation of connecting the tip end portion (one end portion) 12a of the electrode take-out metal fitting 12 and the end portion 10a of the lead wire 10 is performed, and the insulator 14 is connected to the connection portion. Is the process of positioning. By this step, an assembly including a ceramic heater 6, a metal outer cylinder 8, an insulator 14, and an electrode take-out metal fitting 12 can be assembled.

More specifically, the electrode take-out metal fitting 12 is moved from the upper side to the lower side (in the direction of arrow B shown in FIG. 5 (b)), and as shown in FIG. 5 (c), the electrode take-out metal fitting 12 is moved above the insulator 14. To install. At this time, an electrical connection and a physical connection are made between the electrode take-out metal fitting 12 and the lead wire 10.

That is, first, the end portion 10a of the lead wire 10 is inserted into the insertion hole 12f formed in the end surface 12b of the electrode take-out metal fitting 12, and then directed toward the insulator 14 attached to the upper portion of the metal outer cylinder 8 in the previous step. Then, the electrode take-out metal fitting 12 is moved. Since the through hole 14a of the insulator 14 coincides with the central axis of the metal outer cylinder 8, the end portion 10a of the lead wire 10
Can be easily inserted into the insertion hole 12f.

Then, the tip portion 12a of the electrode take-out metal fitting 12 is fitted into the recess 14h located above the insulator 14. Also at this time, since the through hole 14a of the insulator 14 coincides with the central axis of the metal outer cylinder 8, the end portion 12a can be easily fitted into the recess 14h without precise alignment. it can.

An insulator 12g is fixed and attached in advance to a position of the electrode take-out metal fitting 12 near the rear end portion 12d by a method such as insert molding or press-fitting.
The tip portion 12a of the electrode take-out metal fitting 12 is lightly press-fitted into the recess 14h of the insulator 14. Therefore, it is smoothly press-fitted, and after fitting, it becomes a stable temporary fixing state. Although not provided in this embodiment so that light press-fitting between the two can be preferably realized, a rib such as a rib 14f provided in the small diameter portion 14b of the insulator 14 may be provided on the inner peripheral wall of the recess 14h. I do not care.

It should be noted that the inner diameter of the recess 14h in the insulator 14 (in the case where the rib is provided, the inner diameter including the overhang thereof. Hereinafter, both are collectively referred to as simply “inner diameter”) and the tip portion 12a of the electrode take-out metal fitting 12 ( The outer diameter) is preferably lightly press-fitted as in the present embodiment. However, in the first manufacturing method, the relationship between the two is not completely fitted, and the outer diameter of the tip portion 12a is smaller than the inner diameter of the recess 14h, and the outer diameter of the tip portion 12a is changed to the inner diameter of the recess 14h. As long as the outer diameter of the tip portion 12a is larger than that of the tip portion 12a, the tip portion 12a may not be fitted unless it is press-fitted strongly to some extent.

When the tip portion 12a of the electrode take-out metal fitting 12 is lightly press-fitted into the recess 14h of the insulator 14, the end surface 12b of the tip portion 12a of the electrode take-out metal fitting 12 comes into contact with the bottom 14i of the recess 14h. When the end surface 12b comes into contact with the bottom 14i, positioning (temporary fixing) is performed between the electrode take-out metal fitting 12 and the insulator 14, and the positional relationship between the two becomes stable.

Further, in the previous step, the step portion 14d and the opening end 8c are in contact with each other, and the positional relationship between the insulator 14 and the metal outer cylinder 8 is stable, and in this step, the end face 12b and the bottom 14i Is in contact with each other, and the positional relationship between the electrode take-out metal fitting 12 and the insulator 14 is in a stable state.

That is, the relationship between the electrode take-out metal fitting 12 and the metal outer cylinder 8 is in a stable state via the insulator 14. Therefore, the positional relationship between these members can be stably maintained in the middle stage of assembling the ceramic heater 6, the metal outer cylinder 8, the insulator 14, and the electrode take-out metal fitting 12 in order. Further, even in the assembled state in which the electrode take-out metal fittings 12 are assembled, the positional relationship of each member can be stably maintained.

By holding each of these stable members, the operation up to this step can be performed easily and surely, and in the subsequent steps (lead wire tying step, housing mounting step, etc.), all the assembled parts are assembled. Since the positional relationship of the members is stable, the operation can be performed easily and reliably.

(Lead wire binding process)
Next, in the present embodiment, the operation of the lead wire binding step is performed. In the first manufacturing method, in the lead wire binding step, as shown in FIG. 5 (d), the axial direction in which the lead wire 10 inserted in the insertion hole 12f is present (the direction of the double-headed arrow D in FIGS. 1 and 2). In the step of binding the electrode take-out metal fitting 12 and the lead wire 10 by the operation of reducing the diameter of the outer periphery of the electrode take-out metal fitting 12 at the axial direction (double-headed arrow D direction) position where the insulator 14 does not exist. is there.

The electrode take-out metal fitting 12 and the lead wire 10 can be connected by press-fitting the end portion 10a of the lead wire 10 into the insertion hole 12f, but the two can be firmly tied together through this step. .. In particular, in the present embodiment, since the fixing point between the electrode take-out metal fitting 12 and the lead wire 10 is on the outside of the metal outer cylinder 8, the process of binding by reducing the diameter can be easily carried out, and the quality of binding can be improved. Can be done.

The diameter reduction operation may be performed so as to narrow down the electrode take-out metal fitting 12 from the outside as shown by the arrow E in FIG. 5 (d). Specifically, for example, a method of reducing the diameter by tightening with a jig composed of two semi-annular and small-diameter members can be mentioned. By the operation of this step, the outer diameter of the electrode take-out metal fitting 12 of the diameter-reduced portion 12c in FIG. 5 (d) is reduced, and the electrode take-out metal fitting 12 and the lead wire 10 can be firmly tied together.

In order to realize the operation of this step, in the axial direction (double-headed arrow D direction), there is a position where the lead wire 10 inserted in the insertion hole 12f exists and the position where the insulator 14 does not exist. There must be. Therefore, it is desirable that the depth of the recess 14h in the insulator 14 is not too large (not too deep). On the other hand, if the depth of the recess 14h is too small (shallow), the positioning (temporary fixing) between the electrode take-out metal fitting 12 and the insulator 14 becomes unstable. Therefore, in the axial direction (double-headed arrow D direction), the depth of the recess 14h is set to the electrode at the position where the lead wire 10 inserted in the insertion hole 12f exists and the position where the insulator 14 does not exist occurs. It is desirable that the size (depth) is suitable for positioning (temporary fixing) between the take-out metal fitting 12 and the insulator 14.

(Housing mounting process)
In the first manufacturing method, in the housing mounting step, the rear end (the other end) of the metal outer cylinder 8 is arranged so that the connection portion between the electrode extraction metal fitting 12 and the insulator 14 is located in the internal hole 4 of the housing 2. ) 8b is a step of fixing the end opening 2a of the internal hole 4.

Specifically, in this step, first, an assembly composed of a ceramic heater 6, a metal outer cylinder 8, an insulator 14, and an electrode take-out metal fitting 12 is inserted into the other end opening 2b of the housing 2 from the ceramic heater 6 side. .. Then, as shown in FIG. 5 (e), the housing 2 is moved in the direction of the arrow F, and at a predetermined position, the rear end (other end) side of the metal outer cylinder 8 8b and the internal hole 4 of the housing 2 Fix the end opening 2a. The rear end (other end) 8b side of the metal outer cylinder 8 and the end opening 2a of the internal hole 4 of the housing 2 are fixed by press fitting or brazing.

As shown in FIG. 2, there is a slight gap between the inner peripheral surface of the large diameter portion 4a of the internal hole 4 of the housing 2 and the outer peripheral surface of the large diameter portion 14c of the insulator 14. On the other hand, the outer diameter of the metal outer cylinder 8 is substantially the same as the large diameter portion 14c of the insulator 14 at the rear end (other end) 8b, but the diameter is increased toward the tip (one end) 8a. There is no gap between the large diameter portion 4a and the inner peripheral surface, and it is in a state where it cannot enter unless it is press-fitted.

Therefore, it is preferable to apply a lubricant to the inner peripheral surface of the large diameter portion 4a of the internal hole 4 of the housing 2. By applying a lubricant to the inner peripheral surface of the housing 2, when the assembly is inserted into the inner hole 4 of the housing 2, the lubricant is leveled on the outer peripheral surface of the insulator 14 which is very close to the housing 2. Lubricability can be imparted to the inner peripheral surface of the housing.

When the assembly is inserted into the inner peripheral surface of the housing 2, the inner peripheral surface of the inner hole 4 whose lubricity is improved on the outer peripheral surface of the insulator 14 is immediately press-fitted with the inner peripheral surface of the housing 2. However, due to the improved lubricity effect, it can be easily press-fitted. As the lubricant that can be used on the inner peripheral surface of the inner hole 4 of the housing 2, a powdery lubricant or a liquid lubricant may be used, and conventionally known lubricants can be used.

The outer diameter of the insulator 12g attached to the electrode take-out metal fitting 12 at a position closer to the rear end portion 12d is designed to be slightly smaller than the inner diameter of the small diameter portion 14b of the internal hole 4 of the housing 2. Therefore, when the assembly is inserted into the internal hole 4 of the housing 2, the portion where the insulator 12g is attached advances to a predetermined position of the small diameter portion 14b.

If the difference between the outer diameter of the insulator 12g and the inner diameter of the small diameter portion 14b is small, it can function as a support member for the electrode take-out metal fitting 12, but in order to realize more stable support of the electrode take-out metal fitting 12. It is desirable to bond the outer peripheral surface of the insulator 12g and the inner peripheral surface of the inner hole 4 of the housing 2.

To bond the outer peripheral surface of the insulator 12g to the inner peripheral surface of the inner hole 4 of the housing 2, the insulator 12g is placed at a predetermined position shown in FIG. 5 (e) after the assembly has been inserted into the inner hole 4 of the housing 2. Do it after arranging. The method of adhering the two is not particularly limited, and examples thereof include a method of injecting an adhesive into the gap between the two and performing a predetermined curing treatment (heating, ultraviolet irradiation, leaving, etc.). Further, after arranging the insulator 12g at a predetermined position shown in FIG. 5E, the outer circumference of the housing 2 at the position where the insulator 12g is located may be fixed by reducing the diameter.

The vicinity of the rear end portion 12d of the electrode take-out metal fitting 12 projects from the other end opening 2b of the housing 2. Then, although not shown in FIG. 5 (e), the seal member 20 is inserted from the rear end portion 12d of the electrode take-out metal fitting 12 and fitted into the end opening 2a of the small diameter portion 4b of the internal hole 4 of the housing 2. , Fixed by an insulating nut 26.

As described above, the ceramic heater type glow plug of the present embodiment described above can be manufactured by the first manufacturing method. A round pin 18 is connected to the rear end portion 12d of the manufactured glow plug electrode take-out metal fitting 12 that penetrates the nut 26 and is used (see FIG. 1).

<Second manufacturing method>
The second manufacturing method is a manufacturing method in which a metal outer cylinder mounting process, an insulator temporary fixing process, a four-part integration process, and a housing mounting process are performed in this order after the four-part integration process. (4) A lead wire tying step is included as necessary between the component integration step and the housing mounting step.
Hereinafter, each step will be described step by step with reference to FIG. Note that FIG. 6 is a schematic cross-sectional view showing the manufacturing process in the order of (a) to (e) when the operations are performed in order following each step in the second manufacturing method.

(Metal outer cylinder mounting process)
In the second manufacturing method, in the metal outer cylinder mounting step, as shown in FIG. 6A, the end face 6b from which the lead wire 10 protrudes is located inside the ceramic heater 6, and the lead wire 10 penetrates the ceramic heater 6. This is a step of fixing the metal outer cylinder 8 to the ceramic heater 6 by performing an operation of inserting the metal outer cylinder 8 so as to be exposed. Since the metal outer cylinder mounting step in the second manufacturing method is the same step as the metal outer cylinder mounting step in the first manufacturing method, detailed description thereof will be omitted.

(Insulator temporary fixing process)
In the second manufacturing method, in the temporary fixing step of the insulator, as shown in FIG. 6B, the side of the insulator 14 opposite to the side to be fitted into the metal outer cylinder 8 is the tip portion of the electrode take-out metal fitting 12 ( This is a step of performing an operation of temporarily fixing to one end) 12a.

Specifically, as shown in FIG. 6B, the insulator 14 is moved toward the tip portion 12a of the electrode take-out metal fitting 12 (in the direction of arrow G), and the electrode take-out metal fitting 12 is placed in the recess 14h of the insulator 14. The tip portion 12a is fitted. The tip portion 12a of the electrode take-out metal fitting 12 is lightly press-fitted into the recess 14h of the insulator 14.

In the unit Y obtained by the operation of this step, as shown in FIG. 6B, both the through hole 14a of the insulator 14 and the insertion hole 12f of the electrode take-out metal fitting 12 are located on the central axis. It communicates in a straight line from the top, making it look like a single communication hole.

The relationship between the inner diameter of the recess 14h in the insulator 14 and the tip portion 12a (outer diameter) of the electrode take-out metal fitting 12 and other configurations relating to the connection between the two are the same as those described in the electrode take-out metal fitting mounting step in the first manufacturing method. Since the same is true, the detailed description thereof will be omitted.

The metal outer cylinder mounting step and the insulator temporary fixing step described so far are separate and independent steps, and either of them may be performed first or may be performed at the same time. Further, each unit may be manufactured by performing the operation of each step at another place, and the obtained two types of units may be used for the operation of the subsequent steps described below.

(Four parts integration process)
In the second manufacturing method, the four-part integration step is obtained by operating the unit X consisting of the two parts shown in FIG. 6A obtained by operating the metal outer cylinder mounting step and the insulator temporary fixing step. This is a step of uniting and integrating the unit Y composed of the two parts shown in FIG. 6B.

More specifically, as shown in FIG. 6C, the metal in the insulator 14 temporarily fixed to the electrode take-out metal fitting 12 at the rear end (the other end) 8b of the metal outer cylinder 8 to which the ceramic heater 6 is fixed. The side to be fitted into the outer cylinder 8 (large diameter portion 4a side) is brought closer. Then, while passing the lead wire 10 through the through hole 14a, at least a part (in this example, a small diameter portion 14b corresponding to a part of the insulator 14) is provided at the rear end (other end) 8b of the metal outer cylinder 8. Make it fit. At this time, at the same time, the tip end portion (one end portion) 12a of the electrode take-out metal fitting 12 and the end portion 10a of the lead wire 10 are connected. The four-component integration step is a step of locating the insulator 14 at the connecting portion between the tip end portion (one end portion) 12a of the electrode take-out metal fitting 12 and the end portion 10a of the lead wire 10 by the above operation.

More specifically, first, the unit X is fixed vertically, and the unit Y is moved downward to unite and integrate the two. The unit X is held in a state where the rear end 8b of the metal outer cylinder 8 attached to the upper part of the ceramic heater 6 is located above. The unit Y is lowered with the insulator 14 side downward, and the rear end 8b and the insulator 14 are brought closer to each other.

Then, the lead wire 10 is inserted into the through hole 14a and further lowered as it is, and at least a part (in this example, a part of the insulator 14) corresponds to the rear end (the other end) 8b of the metal outer cylinder 8. The small diameter portion 14b) to be fitted is fitted. At this time, the lead wire 10 penetrates the through hole 14a, and the tip thereof reaches the insertion hole 12f of the communicating electrode take-out metal fitting 12 (see FIG. 6C). ..

As described above, the assembly shown in FIG. 6 (c) including the ceramic heater 6, the metal outer cylinder 8, the insulator 14, and the electrode take-out metal fitting 12 is assembled by the operation of this step.
The relationship between the opening (inner diameter) of the rear end 8b of the metal outer cylinder 8 and the small diameter portion 14b of the insulator 14, and other configurations relating to the connection between the two are the same as those described in the insulator mounting step in the first manufacturing method. Therefore, the detailed description thereof will be omitted.

Further, the assembly assembled by the operation of this step is the same as the assembly shown in FIG. 5C assembled by the operation of the electrode take-out metal fitting mounting step in the first manufacturing method, and will be described in the electrode take-out metal fitting mounting step. Since it is the same as the contents described above, detailed description thereof will be omitted.

(Lead wire binding process)
Next, in the present embodiment, the operation of the lead wire binding step is performed. In the second manufacturing method, as shown in FIG. 6D, the lead wire tying step is performed in the axial direction (the double-headed arrow D direction of FIGS. 1 and 2) in which the lead wire 10 inserted in the insertion hole 12f is present. In the step of binding the electrode take-out metal fitting 12 and the lead wire 10 by the operation of reducing the diameter of the outer periphery of the electrode take-out metal fitting 12 at the axial direction (double-headed arrow D direction) position where the insulator 14 does not exist. is there.
Since this step is the same as the lead wire binding step in the first manufacturing method and has already been described in detail in the first manufacturing method, the detailed description thereof will be omitted.

(Housing mounting process)
In the second manufacturing method, in the housing mounting step, the rear end (the other end) of the metal outer cylinder 8 is arranged so that the connection portion between the electrode extraction metal fitting 12 and the insulator 14 is located in the internal hole 4 of the housing 2. ) 8b is a step of fixing the end opening 2a of the internal hole 4 (see FIG. 6E).
Since this step is also the same as the housing mounting step in the first manufacturing method and has already been described in detail in the first manufacturing method, the detailed description thereof will be omitted.

As described above, the ceramic heater type glow plug of the present embodiment described above can be manufactured by the second manufacturing method. A round pin 18 is connected to the rear end portion 12d of the manufactured glow plug electrode take-out metal fitting 12 that penetrates the nut 26 and is used (see FIG. 1).

As described above, in the first manufacturing method, the ceramic heater 6 is held in a vertical state, and the other members are sequentially assembled in the vertical direction to easily and accurately obtain the ceramic heater type glow plug of the present embodiment. Can be manufactured. On the other hand, in the second manufacturing method, the ceramic heater type glow plug of the present embodiment can be manufactured by assembling the unit X and the unit Y separately and integrating them into one, and the division of labor of the assembly. Suitable for ceramics.
That is, the ceramic heater type glow plug of the present embodiment has a high degree of freedom in the manufacturing method because it can be manufactured easily, at low cost, and in a simple process by simply preparing one insulator 14 having a simple configuration. It has the merit such as.

Although the ceramic heater type glow plug of the present invention and the method for manufacturing the same have been described above with reference to preferred embodiments, the ceramic heater type glow plug of the present invention and the method for manufacturing the same are limited to the configuration of the above embodiment. is not. For example, in the above embodiment, as a method of connecting the electrode take-out metal fitting 12 and the lead wire 10, the end portion 10a of the lead wire 10 is press-fitted into the insertion hole 12f, and the diameter is reduced by the reduced diameter portion 12c. Although the characteristic method of binding the two is given as an example, the tightening due to the reduced diameter may be omitted, and the insertion of the end portion 10a of the lead wire 10 into the insertion hole 12f is not press-fitted. It doesn't matter. In the present invention, the connection may be made by a method completely different from that of the present embodiment.

In addition, those skilled in the art can appropriately modify the ceramic heater type glow plug of the present invention and the method for producing the same according to conventionally known knowledge. As long as the modification still has the structure of the present invention, it is, of course, included in the category of the present invention.

2: Housing, 2a: End opening, 2b: End opening, 4: Internal hole, 4a: Large diameter part, 4b: Small diameter part, 6: Ceramic heater, 6a: Heat generating part, 6b: End face, 8: Metal Outer cylinder, 8a: tip (one end), 8b: rear end (other end), 8c: open end, 10: lead wire, 10a: end, 12: electrode take-out bracket, 12a: tip (one) (End), 12b: End face, 12c: Reduced diameter, 12d: Rear end, 12e: Knurled, 12f: Insert hole, 12g: Insulator, 14: Insulator, 14a: Through hole, 14b: Small diameter, 14c: Large diameter part, 14d: Step part, 14e: Inclined part, 14f: Rib, 14g: Equal height part, 14h: Recessed part, 14i: Bottom, 18: Round pin, 20: Seal member (O-ring), 26: Insulator, X: unit, Y: unit

Claims (10)

A heating element made of an inorganic conductor and a ceramic heater made of insulating ceramics,
A metal outer cylinder in which the ceramic heater is fixed in one end and the other end is fixed in the inner hole of the housing.
An electrode taken out of a rod-shaped rigid body, one end of which is connected to the end of a lead wire connected to the heating element, which protrudes from the end face of the ceramic heater located in the metal outer cylinder. With metal fittings
An insulator located at a connection portion between the electrode take-out metal fitting and the lead wire, having a through hole through which the lead wire penetrates, and at least partially fitting into the other end of the metal outer cylinder.
Ceramic heater type glow plug equipped with. The ceramic heater according to claim 1, wherein a recess in the insulator into which one end of the electrode extraction fitting is fitted is formed on a side opposite to the side of the insulator that fits into the metal outer cylinder. Type glow plug. The ceramic heater type glow plug according to claim 2, wherein the tip end of the one end of the electrode take-out metal fitting is in contact with the bottom of the recess in the recess to be fitted. The metal outer cylinder is connected by a small diameter portion fitted into the other end of the metal outer cylinder, a large diameter portion having a diameter larger than the small diameter portion, and the large diameter portion and the small diameter portion. The ceramic heater type glow plug according to any one of claims 1 to 3, further comprising a step portion in contact with the open end at the other end of the above. The small-diameter portion is provided with a rib having an inclined portion whose height gradually increases from the tip end side of the small-diameter portion toward the step portion over the entire area in the fitting direction or a part thereof. The ceramic heater type glow plug according to claim 4. An insertion hole is formed in the end face of the one end of the electrode take-out metal fitting.
The ceramic according to any one of claims 1 to 5, wherein the electrode take-out metal fitting and the lead wire are connected by inserting the end portion of the lead wire into the insertion hole. Heater type glow plug. The insertion hole extends in the axial direction of the electrode take-out metal fitting.
The axial position where the lead wire inserted into the insertion hole exists, and the axial position where the insulator does not exist, has a reduced diameter portion in which the outer circumference of the electrode extraction metal fitting is reduced in diameter. The ceramic heater type glow plug according to claim 6, which is characterized. A manufacturing method for manufacturing a ceramic heater type glow plug according to any one of claims 1 to 7.
A metal outer cylinder mounting step of inserting and fixing the ceramic heater into the metal outer cylinder so that the end portion from which the lead wire protrudes is located inside and the lead wire penetrates and is exposed.
An insulator mounting step in which at least a part of the insulator is fitted into the other end of the metal outer cylinder while the lead wire is passed through the through hole.
An electrode take-out metal fitting attachment step of connecting the one end of the electrode take-out metal fitting and the end of the lead wire to position the insulator at the connection part.
A housing mounting step of fixing the other end of the metal outer cylinder to the end opening of the internal hole so that the connection portion is located in the internal hole of the housing.
A method for manufacturing a ceramic heater type glow plug, which comprises performing the above in this order. A manufacturing method for manufacturing a ceramic heater type glow plug according to any one of claims 1 to 7.
A metal outer cylinder mounting step of inserting and fixing the ceramic heater into the metal outer cylinder so that the end portion from which the lead wire protrudes is located inside and the lead wire penetrates and is exposed.
An insulator temporary fixing step of temporarily fixing the side of the insulator opposite to the side to be fitted into the metal outer cylinder to the one end of the electrode take-out metal fitting.
The other end of the metal outer cylinder to which the ceramic heater is fixed is brought closer to the side of the insulator temporarily fixed to the electrode take-out metal fitting to be fitted into the metal outer cylinder, and the lead is inserted into the through hole. While penetrating the wire, at least a part of the metal outer cylinder is fitted into the other end, and at the same time, the one end of the electrode take-out metal fitting and the end of the lead wire are connected to each other. A four-component integration process that positions the insulator in the unit,
A housing mounting step of fixing the other end of the metal outer cylinder to the end opening of the internal hole so that the connection portion is located in the internal hole of the housing.
A method for manufacturing ceramic heater type glow plugs, which is characterized in that the steps are performed in this order after the four-part integration process. An insertion hole is formed in the end surface of the one end of the electrode take-out metal fitting and extends in the axial direction of the electrode take-out metal fitting.
The connection between the electrode take-out metal fitting and the lead wire is made by inserting the end portion of the lead wire into the insertion hole.
Prior to the housing mounting step, the outer diameter of the electrode extraction fitting is reduced at the axial position where the lead wire inserted into the insertion hole exists and at the axial position where the insulator does not exist. The method for manufacturing a ceramic heater type glow plug according to claim 8 or 9, wherein the lead wire binding step for binding the electrode take-out metal fitting and the lead wire is provided.

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