JP2020197353A - Heater device - Google Patents

Abstract

To provide a heater device that has water tightness secured between a sheath pipe and a housing.SOLUTION: A heater device 10 according to the present invention comprises: a cylindrical sheath pipe 810; a heating element 820 which is arranged in the sheath pipe 810, and is powered to generate heat; a cylindrical housing 500; and a press-in part 552 which consists of overlapping parts of a cylindrical first peripheral wall part 815 on a rear end side of the sheath pipe 810 and a cylindrical second peripheral wall part 550 on a front end side of the housing 500 as the first peripheral wall part 815 is pressed into the second peripheral wall part 550. The sheath pipe 810 and the housing 500 are formed of an alloy which includes 0-0.08 mass% of carbon (C), 1.0-2.0 mass% of manganese (Mn), 0-0.01 mass% of sulfur (S), and iron (Fe) as a principal ingredient, and the press-in part 552 comprises a molting part 560 which is formed by welding a part of the first peripheral wall part 815 and a part of the second peripheral wall part 550 to each other.SELECTED DRAWING: Figure 4

Description

The present invention relates to a heater device.

A general glow plug is used as an auxiliary heat source in a compression ignition type internal combustion engine (for example, a diesel engine). This glow plug usually includes a bottomed tubular sheath tube whose tip is closed and whose rear end is open, and a heating element which is arranged inside the sheath tube and generates heat when energized. Further, the glow plug includes a tubular housing (so-called main metal fitting) that inserts and holds the rear end side of the sheath tube into its own tubular hole while projecting the tip end side of the sheath tube.

By the way, in recent years, it is known that glow plugs are used not only as an auxiliary heat source for internal combustion engines but also as a heating source for liquids. In the following, the glow plug used as a heating source for the liquid will be referred to as a heater device. For example, by exposing the sheath tube of the heater device to a liquid such as oil or washer fluid used in an internal combustion engine, the heat generated by the heating element is conducted to the liquid through the sheath tube to heat the liquid. Can be done.

When the heater device is used as a heating source for the liquid, the watertightness between the sheath tube and the housing is important in order to prevent the liquid from entering the housing. Therefore, it is known that the sheath tube and the housing are laser welded in the circumferential direction (see Patent Document 1).

Special Table 2012-509452

As described above, when the sheath tube and the housing are laser welded in the circumferential direction, cracks may occur in the formed molten portion. As a result, the watertightness between the sheath tube and the housing is reduced.

Such laser welding is performed at a portion (press-fitted portion) in which the sheath tube is press-fitted into the housing. Therefore, the press-fitting stress between the housing and the sheath pipe is released at the welded portion, and a tensile stress is further generated at the welded portion. In such a press-fitted portion, it has been difficult and problematic to weld the sheath tube and the housing while ensuring watertightness.

An object of the present invention is to provide a heater device in which watertightness between a sheath tube and a housing (main metal fitting) is ensured.

The means for solving the above problems are as follows. That is,
<1> A tubular sheath tube whose tip is closed and whose rear end is open and which extends in the axial direction, a heating element which is arranged in the sheath tube and generates heat by energization, and a tubular shape whose tip and rear end are both open. The housing and the tubular first peripheral wall portion on the rear end side of the sheath tube are press-fitted into the inside of the tubular second peripheral wall portion on the distal end side of the housing to form the first peripheral wall portion. A heater device including a press-fitting portion formed of a portion in which the second peripheral wall portion overlaps with each other, wherein the sheath tube and the housing contain 0% by mass or more and 0.08% by mass or less of carbon (C) and manganese. (Mn) is 1.0% by mass or more and 2.0% by mass or less, sulfur (S) is 0% by mass or more and 0.01% by mass or less, and is formed from an alloy containing iron (Fe) as a main component. A heater device including a molten portion formed by welding a part of the first peripheral wall portion and a part of the second peripheral wall portion to each other.

<2> The housing has a tubular main body portion and a tubular thin-walled portion which is arranged on the tip end side of the main body portion, forms the second peripheral wall portion, and is thinner than the thickness of the main body portion. The heater device according to <1>, wherein the thickness of the thin-walled portion is thinner than the thickness of the first peripheral wall portion.

<3> The press-fitting portion is adjacent to the tip side of the sheath pipe with respect to the melted portion, and is not welded to the front side non-welded portion, and to the molten portion, the rear portion of the sheath pipe. The heater device according to <1> or <2>, wherein the heater device is adjacent to the end side and has an unwelded rear non-welded portion.

<4> With respect to the length (L) of the press-fitting portion in the axial direction, the width (d1) of the front non-welded portion in the axial direction and the width (d2) of the rear non-welded portion in the axial direction. The heater device according to <3>, wherein the ratio ((d1 + d2) / L) of the total width (d1 + d2) including the above is 0.6 or more.

According to the present invention, it is possible to provide a heater device in which watertightness between the sheath tube and the housing (main metal fitting) is ensured.

Explanatory drawing which shows the state which arranged the heater device which concerns on Embodiment 1 in a container Semi-sectional view of the heater device Sectional drawing which shows the detailed structure of a sheath heater Cross-sectional view near the second peripheral wall of the main metal fitting Cross-sectional view of the vicinity of the fused portion provided in the press-fitted portion

<Embodiment 1>
Hereinafter, Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 5. FIG. 1 is an explanatory diagram showing a state in which the heater device 10 according to the first embodiment is arranged in the container 1. As shown in FIG. 1, a liquid (for example, oil, washer liquid, etc.) 2 is contained in the box-shaped container 1. A mounting portion 3 for mounting the heater device 10 is formed on the upper portion of the container 1. The mounting portion 3 is provided with a mounting hole 4 through which the heater device 10 is inserted, and the inner surface of the mounting portion 3 facing the mounting hole 4 is screwed with a male screw portion 540 (described later) of the heater device 10. A female screw portion 5 is provided. When the heater device 10 is attached to the attachment portion 3, the tip end side of the heater device 10 protrudes into the container 1 and is exposed to the liquid 2.

FIG. 2 is a half cross-sectional view of the heater device 10. As shown in FIG. 2, the heater device 10 mainly includes a sheath heater 800, a center pole 200, and a main metal fitting (housing) 500. The members constituting these heater devices 10 are assembled along the direction of the axis O of the heater device 10 (hereinafter, the axial direction OD). In FIG. 2, the appearance configuration is shown on the right side of the paper surface from the axis O, and the cross-sectional configuration is shown on the left side of the paper surface from the axis O. In the present specification, the sheath heater 800 side of the heater device 10 is referred to as "tip side", and the engaging member 100 side on the opposite side is referred to as "rear end side".

The main metal fitting (housing) 500 is a tubular member having both a front end and a rear end open. In the main metal fitting 500, carbon (C) is 0% by mass or more and 0.08% by mass or less, manganese (Mn) is 1.0% by mass or more and 2.0% by mass or less, and sulfur (S) is 0% by mass or more and 0% by mass. It is formed from an alloy containing 01% by mass or less and containing iron (Fe) as a main component.

The main metal fitting 500 holds the sheath heater 800 at the end on the tip side. Further, the main metal fitting 500 holds the center pole 200 at the rear end side via the insulating member 410 and the O-ring 460. The insulating member 410 is fixed to the main metal fitting 500 by crimping the ring 300 in contact with the rear end to the center pole 200. Further, in the shaft hole 510 of the main metal fitting 500, a center pole 200 extending from the insulating member 410 to the sheath heater 800 is arranged. The shaft hole 510 is a through hole formed along the axis O and has a diameter larger than that of the center pole 200. With the center pole 200 positioned in the shaft hole 510, a gap is formed between the shaft hole 510 and the center pole 200 to electrically insulate them. Further, the main metal fitting 500 includes a main body portion 530 and a thin-walled portion 550 having a thickness thinner than the thickness of the main body portion 530. The main body portion 530 is provided with a tool engaging portion 520 and a male screw portion 540.

The tool engaging portion 520 of the main metal fitting 500 engages with a tool (not shown) used for attaching and detaching the heater device 10. The male screw portion 540 fits into the female screw portion 5 formed in the container 1. Further, a tubular second peripheral wall portion (thin wall portion) 550 is provided on the tip side of the main body portion 530, and the sheath heater 800 is placed inside the second peripheral wall portion (thin wall portion) 550 (shaft hole 510). In the press-fitted state, it is laser welded to the thin-walled portion 550. The structure of the sheath heater 800 and the second peripheral wall portion 550 will be described later.

The center pole 200 is a member formed of a conductive material in a columnar shape (rod shape). The center pole 200 is assembled along the axial direction OD in a state of being inserted into the shaft hole 510 of the main metal fitting 500. The center pole 200 includes a tip portion 210 formed on the front end side and a male screw portion 290 provided on the rear end side. The tip 210 is inserted inside the sheath heater 800. The male screw portion 290 protrudes from the main metal fitting 500 toward the rear end side. The engaging member 100 fits into the male screw portion 290.

FIG. 3 is a cross-sectional view showing a detailed configuration of the sheath heater 800. The sheath heater 800 is press-fitted into the shaft hole 510 of the main metal fitting 500 with the tip portion 210 of the center pole 200 inserted inside the sheath heater 800. The sheath heater 800 mainly includes a sheath tube 810, a heating coil (heating element) 820, and an insulator 870.

As a whole, the sheath tube 810 is a tubular member whose tip is closed and whose rear end is open and extends in the axial direction OD. Such a sheath tube 810 includes a heating coil 820 and an insulator 870. The sheath tube 810 is connected to a tubular side surface portion 814 extending along the axial direction OD and the tip end side of the side surface portion 814, and is formed in a round shape toward the outside, and is opposite to the tip portion 811. It is provided with a rear end portion 819 which is an end portion opened to the side. The tip 210 of the center pole 200 is inserted into the sheath tube 810 from the rear end 819. The sheath tube 810 is electrically insulated from the center pole 200 by the packing 600 and the insulator 870. On the other hand, the sheath tube 810 is in contact with the main metal fitting 500 and is electrically connected. The portion of the tubular side surface portion 814 that is press-fitted into the second peripheral wall portion 550 of the main metal fitting 500 is particularly referred to as the “first peripheral wall portion 815”.

The sheath tube 810 is made of the same material as the main metal fitting 500 described above. Specifically, the sheath tube 810 has carbon (C) of 0% by mass or more and 0.08% by mass or less, manganese (Mn) of 1.0% by mass or more and 2.0% by mass or less, and sulfur (S) of 0. It is formed from an alloy containing mass% or more and 0.01% by mass or less and containing iron (Fe) as a main component. The sheath tube 810 and the main metal fitting 500 do not have to be made of the same material, and may be different from each other as long as the object of the present invention is not impaired.

The insulator 870 is formed of a powder of an insulating material having an electrically insulating property. As the insulator 870, for example, magnesium oxide (MgO) powder is used. In the insulator 870, the sheath tube 810 is filled (arranged) in the gap formed in the sheath tube 810 by including the center pole 200 and the heating coil 820, and the gap is electrically insulated.

The heat generating coil 820 is arranged inside the sheath tube 810 along the axial direction OD, and generates heat when energized. The heating coil 820 has a tip portion 822 which is a coil end portion on the tip end side, a rear end portion 829 which is a coil end portion on the rear end side, and a spiral portion 823 which connects the tip end portion 822 and the rear end portion 829. Be prepared. The tip portion 822 is connected to the tip portion 811 of the sheath tube 810 and is electrically connected to the sheath tube 810. The rear end portion 829 is electrically connected to the center pole 200 by being joined to the tip end portion 210 of the center pole 200. The heat generating coil 820 is made of Fe—Cr—Al alloy, Ni—Cr alloy, Co—Ni alloy, Ni or the like.

FIG. 4 is a cross-sectional view of the main metal fitting 500 in the vicinity of the second peripheral wall portion 550. The cross section of FIG. 4 is a cross section of the sheath tube 810 and the main metal fitting 500 cut at a position passing through the axis O. The center pole 200 is shown in a perspective view for simplification. As shown in FIG. 4, the main metal fitting 500 includes a main body portion 530 and a second peripheral wall portion 550. The second peripheral wall portion 550 is connected to the tip end side of the main body portion 530, and the thickness of the second peripheral wall portion 550 is formed to be thinner than the thickness of the main body portion 530.

The sheath tube 810 is inserted inside the main body portion 530 and the second peripheral wall portion 550 (shaft hole 510). At this time, the first peripheral wall portion 815 of the sheath tube 810 is press-fitted into the second peripheral wall portion 550 of the main metal fitting 500. A press-fitting portion 552 is formed by a portion where the first peripheral wall portion 815 of the sheath tube 810 and the second peripheral wall portion 550 of the main metal fitting 500 overlap each other.

Further, a part of the press-fitting portion 552 is laser-welded over the entire circumference, and the melting portion 560 is provided in the circumferential direction. That is, the molten portion 560 is formed by laser welding a part of the second peripheral wall portion 550 and a part of the first peripheral wall portion 815 to each other in the press-fitting portion 552. Such a melting portion 560 is provided so as to overlap the press-fitting portion 552. That is, the press-fitting portion 552 includes a melting portion 560 that connects a part of the first peripheral wall portion 815 and a part of the second peripheral wall portion 550. For laser welding, for example, a YAG laser or the like is used.

FIG. 5 is a cross-sectional view of the vicinity of the melting portion 560 provided in the press-fitting portion 552. In FIG. 5, the molten portion 560 on the left side in FIG. 4 is enlarged. As shown in FIG. 5, the melting portion 560 straddles the virtual boundary line X1 formed between the outer surface 815a of the first peripheral wall portion 815 and the inner surface 550a of the second peripheral wall portion 550. , The shape extends from the second peripheral wall portion 550 (main metal fitting 500) side to the first peripheral wall portion 815 (sheath tube 810) side.

Subsequently, a method of manufacturing the heater device 10 will be described. In the manufacture of the heater device 10, the heating coil 820 and the center pole 200 are first welded.

Next, the tip portion 822 of the heat generating coil 820 and the tip portion 811 of the sheath tube 810 are welded. After that, the sheath tube 810 is filled with the insulator 870. The insulator 870 is filled in the gap formed in the sheath tube 810 by including the heating coil 820 and the center pole 200, and the assembly of the sheath heater 800 is completed.

When the sheath heater 800 is assembled, the sheath heater 800 is subjected to a swaging process. The swaging process is a process of applying a striking force to the sheath heater 800 to reduce the diameter of the sheath heater 800 and densify the insulator 870 filled in the sheath tube 810. When a striking force is applied to the sheath heater 800 during the swaging process, the striking force is transmitted to the inside of the sheath heater 800, so that the insulator 870 is densified.

The sheath heater 800 after the swaging process is press-fitted into the main metal fitting 500. When the sheath heater 800 is inserted from the tip end side of the main metal fitting 500, a press-fitting portion 552 in which the second peripheral wall portion 550 and the first peripheral wall portion 815 overlap each other is formed.

After that, the second peripheral wall portion 550 of the main metal fitting 500 and the first peripheral wall portion 815 of the sheath heater 800 are laser welded over the entire circumference to form a molten portion 560 in a part of the press-fitting portion 552.

After the molten portion 560 is formed, the O-ring 460 and the insulating member 410 are fitted into the center pole 200 at the rear end portion of the main metal fitting 500, and the engaging member 100 is further provided at the rear end of the main metal fitting 500. It is tightened to the male screw portion 290 of 200. By going through such a process, the heater device 10 is manufactured.

In the heater device 10 of the present embodiment configured as described above, watertightness between the sheath tube 810 and the main metal fitting (housing) 500 is ensured. In the molten portion 560, the press-fitting stress in the press-fitting portion 552 is released during laser welding, and a tensile stress is further generated in the molten portion 560. However, in the present embodiment, since the first peripheral wall portion 815 and the second peripheral wall portion 550 constituting the press-fitting portion 552 are formed from the specific alloy as described above, the tensile stress as described above is generated. Even under the circumstances, the molten portion 560 having a stable shape is formed while suppressing the occurrence of cracks.

In the case of the present embodiment, even if a crack may occur in a part of the molten portion 560, the watertightness between the first peripheral wall portion 815 of the sheath pipe 810 and the second peripheral wall portion 550 of the main metal fitting 500 The occurrence of cracks to the extent that the properties are impaired is suppressed.

Further, in the present embodiment, as shown in FIG. 4, the press-fitting portion 552 is adjacent to the tip side (tip side of the sheath pipe 810) with respect to the molten portion 560, and is not laser-welded. It is provided with a welded portion 561 and a rear non-welded portion 562 adjacent to the rear end side (rear end side of the sheath pipe 810) with respect to the molten portion 560 and not laser-welded. As described above, in the press-fitting portion 552, the front non-welded portion 561 and the rear non-welded portion 562, which are not laser-welded, are provided after the fusion portion 560, respectively, so that heat drawing during laser welding is satisfactorily performed. Will be done. That is, the heat generated during laser welding moves to the front non-welded portion 561 and the rear non-welded portion 562 and is dissipated. As a result, since the molten portion 560 having a stable shape is obtained, the occurrence of cracks and the like is further suppressed.

As shown in FIG. 4, the width (d1) of the front non-welded portion 561 in the axial direction OD and the rear non-welded portion 562 in the axial direction OD with respect to the length (L) of the press-fitting portion 552 in the axial direction OD. The ratio ((d1 + d2) / L) of the total width (d1 + d2) including the width (d2) of is preferably 0.6 or more. When the ratio is such a value, heat drawing at the time of laser welding can be performed more reliably, and a molten portion 560 having a stable shape can be reliably obtained.

Further, in the present embodiment, the thickness T2 of the second peripheral wall portion (thin wall portion) 550 is thinner (smaller) than the thickness T1 of the first peripheral wall portion 815 of the sheath tube 810. In the present embodiment, the thickness of the entire portion of the second peripheral wall portion 550 is made thinner than the thickness T1 of the first peripheral wall portion 815 of the sheath tube 810. The thickness T2 of the second peripheral wall portion 550 is the second peripheral wall at the boundary S1 (rear end side boundary S1) of the outer surface of the second peripheral wall portion 550 between the rear non-welded portion 562 adjacent to the molten portion 560 and the fused portion 560. It is specified that the thickness of the portion 550 is T2. This is because the shape of the molten portion 560 changes due to welding, so that the thickness of the second peripheral wall portion 550 may not be specified in the fused portion 560, whereas the boundary between the rear non-welded portion 562 and the fused portion 560. This is because if S1 is the starting point, the thickness T2 of the second peripheral wall portion 550 can be easily specified. According to the heater device 10 configured in this way, the thickness T2 of the second peripheral wall portion 550 is thinner than the thickness T1 of the first peripheral wall portion 815 of the sheath tube 810. Thereby, the appropriate size of the molten portion 560 provided in the sheath tube 810 can be adjusted. Moreover, since the thickness T2 of the second peripheral wall portion 550 is thinner (smaller) than the thickness T1 of the first peripheral wall portion 815, the tensile stress generated for the molten portion 560 is, for example, the thickness of the second peripheral wall portion 550. Compared with the case where T2 is the same as the thickness T1 of the first peripheral wall portion 815, it becomes smaller and it becomes easier to obtain a molten portion 560 having a stable shape. As a result, the watertightness of the sheath tube 810 and the main metal fitting 500 can be further ensured. Further, it is possible to suppress that the sheath tube 810 penetrates and the heating coil 820 is oxidatively consumed. In the present embodiment, the thickness T2 of the second peripheral wall portion 550 at the rear end side boundary S1 and the thickness T1 of the first peripheral wall portion 815 of the sheath tube are compared, but in other embodiments, the thickness T1 at the front end side boundary S2. The thickness of the second peripheral wall portion 550 may be compared with the thickness T1 of the first peripheral wall portion 815 of the sheath tube 810.

Hereinafter, the present invention will be described in more detail based on Examples. The present invention is not limited to these examples.

[Example 1]
The heater device of Example 1 having the same structure as the heater device 10 described above was manufactured based on the following manufacturing conditions.

The outer diameter of the sheath tube is 6.20 mm, and the outer diameter of the main metal fitting is 6.94 mm. The target position for welding was a position 2 mm from the tip of the second peripheral wall portion of the main metal fitting. The width (d1) of the front non-welded portion 561 in the axial direction OD is 1.20 mm, and the width (d2) of the rear non-welded portion 562 in the axial direction OD is 1.50 mm. The length (L) of the second peripheral wall portion is 4.00 mm, the thickness of the second peripheral wall portion (thin wall portion) is 0.4 mm, and the thickness of the sheath tube (first peripheral wall portion) is 0. It is 7 mm. Welding was performed using a YAG laser welder under the condition of melting to about half the thickness of the sheath tube. The width of the molten portion (length in the axial direction) is 1.30 mm. Further, (d1 + d2) / L = 0.675.

Further, in the sheath tube and the main metal fitting, carbon (C) is 0.08% by mass, silicon (Si) is 1.00% by mass, manganese (Mn) is 1.00% by mass, and phosphorus (P) is 0, respectively. It was formed from an alloy containing 0.03% by mass, 0.010% by mass of sulfur (S), 10% by mass of nickel (Ni), 18% by mass of chromium (Cr), and iron (Fe) as the balance.

[Examples 2 to 4 and Comparative Examples 1 to 6]
The heater devices of Examples 2 to 4 and Comparative Examples 1 to 6 were produced in the same manner as in Example 1 except that the alloys constituting the sheath tube and the main metal fitting were changed to the alloys having the formulations shown in Table 1. did.

[Airtightness test]
The airtightness test (alternative test of the watertightness test) was performed on the heater devices of each Example and each Comparative Example by the method shown below. Whether or not there is an air leak for 1 minute from the welded part (melting part) between the sheath tube and the main metal fitting by supplying air whose air pressure is adjusted to 1.5 MPa into the main metal fitting of the heater device. It was confirmed. If there was no air leak for 1 minute, it was judged that there was airtightness (watertightness), and if there was an air leak for 1 minute, it was judged that there was no airtightness (watertightness). The results are shown in Table 1. In Table 1, the case where there is airtightness is indicated by “◯”, and the case where there is no airtightness is indicated by “x”.

As shown in Table 1, it was confirmed that the heater devices of Examples 1 to 4 ensured airtightness at the welded portion (melted portion) between the sheath tube and the main metal fitting. That is, it was confirmed that the heater devices of Examples 1 to 4 also have watertightness.

Comparative Example 1 is a case where a large amount of carbon is contained in the alloy constituting the sheath tube and the main metal fitting. In such Comparative Example 1, it is presumed that airtightness cannot be obtained because cracks are likely to occur in the molten portion when the molten portion cools and hardens.

Comparative Examples 2 to 4 are cases where a large amount of sulfur (S) is contained in the alloy constituting the sheath tube and the main metal fitting. In such Comparative Examples 2 to 4, it was confirmed that cracks were generated in the molten portion and airtightness could not be obtained.

Comparative Example 5 is a case where the amount of manganese (Mn) in the alloy constituting the sheath tube and the main metal fitting is too small. In Comparative Example 5 as described above, it was confirmed that cracks were generated in the molten portion and airtightness could not be obtained.

Comparative Example 6 is a case where the manganese (Mn) in the alloy constituting the sheath tube and the main metal fitting is too large. In Comparative Example 6 like this, it was confirmed that cracks were generated in the molten portion and airtightness could not be obtained.

10 ... Heater device, 500 ... Main metal fitting (housing), 530 ... Main body, 550 ... Second peripheral wall, 552 ... Press-fitting part, 560 ... Melted part, 561 ... Front non-welded part, 562 ... Rear non-welded part , 810 ... sheath pipe, 815 ... first peripheral wall portion, 820 ... heating element (heating coil), d1 ... width of front non-welded portion, d2 ... width of rear non-welded portion, O ... axis, OD ... axial direction , L ... Length of press-fitting part

Claims (4)

A tubular sheath tube with a closed tip and an open rear end extending in the axial direction,
A heating element that is placed in the sheath tube and generates heat when energized,
A tubular housing with both front and rear ends open,
The tubular first peripheral wall portion on the rear end side of the sheath tube is press-fitted into the tubular second peripheral wall portion on the distal end side of the housing, whereby the first peripheral wall portion and the second peripheral wall portion are press-fitted. A heater device including a press-fitting portion including a portion in which the portions overlap each other.
In the sheath tube and the housing, carbon (C) is 0% by mass or more and 0.08% by mass or less, manganese (Mn) is 1.0% by mass or more and 2.0% by mass or less, and sulfur (S) is 0% by mass. It contains more than 0.01% by mass and is formed from an alloy containing iron (Fe) as the main component.
A heater device including a molten portion formed by welding a part of the first peripheral wall portion and a part of the second peripheral wall portion to each other in the press-fitting portion. The housing has a tubular main body portion, a tubular thin-walled portion arranged on the tip end side of the main body portion, forming the second peripheral wall portion, and thinner than the thickness of the main body portion.
The heater device according to claim 1, wherein the thickness of the thin portion is thinner than the thickness of the first peripheral wall portion. The press-fitting portion is adjacent to the tip side of the sheath pipe with respect to the melted portion, and is not welded to the front end side non-welded portion and to the melted portion on the rear end side of the sheath pipe. The heater device according to claim 1 or 2, which has an adjacent non-welded rear portion. The width (d1) of the front non-welded portion in the axial direction and the width (d2) of the rear non-welded portion in the axial direction are combined with respect to the length (L) of the press-fit portion in the axial direction. The heater device according to claim 3, wherein the ratio ((d1 + d2) / L) of the total width (d1 + d2) is 0.6 or more.

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