JP6068292B2 - Manufacturing method of spark plug - Google Patents

Description

  The present invention relates to a method for manufacturing a spark plug.

  The spark plug includes a cylindrical insulator and a cylindrical metal shell disposed on the outer periphery of the insulator. A step portion is formed on the inner peripheral surface near the tip of the metal shell, and a step portion formed on the outer peripheral surface of the insulator is in contact with the step portion via an annular member called a plate packing ( For example, see Patent Document 1). The insulator and the metal shell are fixed by crimping the rear end of the metal shell. In the vicinity of the portion to be crimped, an annular member called tal packing and talc are arranged between the inner peripheral surface of the rear end portion of the metal shell and the outer peripheral surface of the insulator.

JP 2006-79954 A JP-A-10-32077

  Conventionally, the plate packing is placed in the metal shell by freely dropping the plate packing from the rear end side of the metal shell. In addition, the wire packing is also arranged by freely dropping the wire packing from the rear end side of the insulator before the caulking process. If the plate packing or wire packing is dropped freely, it may be caught by the terminal fittings located in the metal shell or at the rear end of the insulator during dropping, which may cause the spark plug manufacturing efficiency to decrease. there were. Therefore, there has been a demand for a technique capable of accurately arranging an annular member such as a plate packing or a wire packing at a predetermined portion of the spark plug.

The present invention has been made to solve the above-described problems, and can be realized as the following forms.
A first aspect of the present invention includes: a central electrode extending in the axial direction; a cylindrical insulator disposed on the outer periphery of the central electrode; a cylindrical metal shell disposed on the outer periphery of the insulator; A spark plug manufacturing method comprising: an annular member; and an annular member disposition portion formed between an outer peripheral surface of the insulator and an inner peripheral surface of the metal shell, wherein the annular member is disposed, A first step of disposing the annular member in the annular member arrangement portion along the axial direction using an insertion jig, wherein the annular member is caused by the weight of the insertion jig in the first step; Is arranged in the annular member arrangement portion. The present invention can also be realized as the following forms.

(1) According to one aspect of the present invention, a central electrode extending in the axial direction; a cylindrical insulator disposed on the outer periphery of the central electrode; and a cylindrical main body disposed on the outer periphery of the insulator Provided is a spark plug manufacturing method comprising: a metal fitting; an annular member; and an annular member arrangement portion formed between an outer peripheral surface of the insulator and an inner peripheral surface of the metal shell, and the annular member is arranged thereon. Is done. The manufacturing method includes a first step of arranging the annular member in the annular member arrangement portion along the axial direction using an insertion jig. According to the spark plug manufacturing method of this aspect, the annular member can be accurately arranged in the annular member arrangement portion by using the insertion jig.

(2) In the spark plug manufacturing method, in the first step, the annular member may be arranged in the annular member arrangement portion by the weight of the insertion jig. With such a spark plug manufacturing method, the annular member is disposed in the annular member placement portion by the weight of the insertion jig, and thus the annular member can be more accurately placed in the annular member placement portion. In addition, since the annular member is arranged by its own weight, even if the annular member is caught by the metal shell or the insulator for some reason, it is possible to suppress the insertion jig from biting into the annular member. it can.

(3) In the spark plug manufacturing method, the axial rear end side of the shutter is closed when the shutter disposed closer to the distal end side in the axial direction than the distal end of the insertion jig is closed prior to the first step. The annular member is disposed on the surface of the annular member, and the radial alignment between the annular member and the insertion jig is performed. In the first step, after the shutter is opened, the annular member is You may arrange | position at the said annular member arrangement | positioning part with an insertion jig. With such a spark plug manufacturing method, the annular member and the insertion jig can be reliably aligned on the surface on the rear end side in the axial direction of the shutter. It can arrange | position to an arrangement | positioning part.

(4) In the spark plug manufacturing method, the annular member disposition portion may be a portion surrounded by an outer peripheral surface of the insulator and an inner peripheral surface of a rear end portion of the metal shell. With such a method for manufacturing a spark plug, the annular member can be arranged in a portion closer to the tip side than a portion where the metal shell is caulked.

(5) In the spark plug manufacturing method, the annular member disposition portion includes a first step provided on an inner peripheral surface of the metal shell and an outer peripheral surface of the insulator, and the insulator is the main body. It may be a portion between the first step portion and the second step portion facing the first step portion when inserted into the metal fitting. With such a method for manufacturing a spark plug, the annular member can be accurately arranged in the portion of the metallic shell where the metallic shell and the insulator are in contact.

(6) In the spark plug manufacturing method, the spark plug has a terminal fitting electrically connected to the center electrode at an end portion of the insulator. You may arrange | position the said annular member in the said annular member arrangement | positioning part using the said insertion jig in the state which hold | suppressed the said terminal metal fitting along the said axial direction using the tool. With such a spark plug manufacturing method, the annular member is arranged in a state in which the terminal fitting is pressed using a holding jig, so that the radial position of the insulator can be fixed. Therefore, the annular member can be more accurately arranged in the annular member arrangement portion.

(7) In the spark plug manufacturing method, the insertion jig has a cylindrical shape, and a guide rod extending in the axial direction is provided in a portion surrounded by an inner peripheral surface of the insertion jig, In the step, the insertion jig may move along the guide rod to dispose the annular member. With such a spark plug manufacturing method, the insertion jig can be moved along the guide rod, so that the annular member can be more accurately arranged in the annular member arrangement portion.

(8) In the spark plug manufacturing method, the position of the insertion jig in the axial direction is further detected by using a detector to determine whether or not the annular member is arranged in the annular member arrangement portion. You may provide the process to judge. With such a spark plug manufacturing method, it is possible to accurately determine whether or not the annular member is arranged in the annular member arrangement portion.

(9) In the spark plug manufacturing method, the annular member may be formed of a magnetic material, and the insertion jig may be formed of a nonmagnetic material or a material that can be demagnetized when magnetized. With such a spark plug manufacturing method, the annular member can be prevented from being magnetized by the insertion jig, so that the annular member can be stably disposed on the annular member placement portion.

(10) In the spark plug manufacturing method, the insertion jig may be formed of an austenitic stainless material. Since the austenitic stainless steel material is a non-magnetic material, it is possible to prevent the annular member from being magnetized by the insertion jig with such a spark plug manufacturing method. As a result, the annular member can be stably arranged on the annular member arrangement portion.

  The present invention is not limited to the above-described method for manufacturing a spark plug, and can be realized in various forms. For example, it can be realized in the form of a spark plug manufactured by the above-described manufacturing method or a vehicle including the spark plug.

It is a fragmentary sectional view of a spark plug. It is a flowchart of the manufacturing method of a spark plug. It is a figure which shows the method of arrange | positioning board packing to a front end side annular member arrangement | positioning part. It is a figure which shows the method of arrange | positioning line packing in a rear end side annular member arrangement | positioning part.

A. Spark plug configuration:
FIG. 1 is a partial cross-sectional view of a spark plug 100. In FIG. 1, the axial direction OD of the spark plug 100 will be described as the vertical direction in the drawing, the lower side will be described as the front end side, and the upper side will be described as the rear end side. In FIG. 1, the right side of the axis O indicated by a one-dot broken line indicates the appearance of the spark plug 100, and the left side of the axis O indicates a cross section passing through the central axis of the spark plug 100.

  The spark plug 100 includes an insulator 10 as an insulator, a metal shell 50, a center electrode 20, a ground electrode 30, and a terminal metal fitting 40. The metal shell 50 is formed with an insertion hole 501 penetrating in the axial direction OD. The insulator 10 is inserted and held in the insertion hole 501. The center electrode 20 is held in the axial hole 12 formed in the insulator 10 along the axial direction OD. The distal end portion of the center electrode 20 is exposed on the distal end side of the insulator 10. The ground electrode 30 is joined to the front end portion of the metal shell 50 (the lower end portion in FIG. 1). The terminal fitting 40 is provided on the rear end side (the upper end portion in FIG. 1) of the center electrode 20. The rear end portion of the terminal fitting 40 is exposed on the rear end side of the insulator 10.

  As is well known, the insulator 10 is formed by firing alumina or the like, and has a cylindrical shape in which an axial hole 12 extending in the axial direction OD is formed. A flange portion 19 having the largest outer diameter is formed substantially at the center in the axial direction OD, and a rear end side body portion 18 is formed on the rear end side (upper side in FIG. 1). A front end side body portion 17 having a smaller outer diameter than the rear end side body portion 18 is formed on the front end side from the flange portion 19 (lower side in FIG. 1). A leg length portion 13 having an outer diameter smaller than that of the distal end side body portion 17 is formed. The long leg portion 13 is reduced in diameter toward the distal end side, and is exposed to the combustion chamber when the spark plug 100 is attached to the engine head 200 of the internal combustion engine.

  The metal shell 50 is a substantially cylindrical metal fitting for fixing the spark plug 100 to the engine head 200 of the internal combustion engine. The metal shell 50 holds the insulator 10 so as to surround a portion from a part of the rear end side body part 18 to the leg long part 13. That is, the insulator 10 is inserted into the insertion hole 501 of the metal shell 50, and the front end and the rear end of the insulator 10 are exposed from the front end and the rear end of the metal shell 50, respectively. The metal shell 50 is made of a low carbon steel material, and is plated with nickel or zinc. A hexagonal column-shaped tool engaging portion 51 with which a spark plug wrench (not shown) is engaged is provided at the rear end portion of the metal shell 50. The metal shell 50 includes a mounting screw portion 52 formed with a screw thread that is screwed into a mounting screw hole 201 of the engine head 200 provided in the upper part of the internal combustion engine.

  Between the tool engaging portion 51 and the mounting screw portion 52 of the metal shell 50, a bowl-shaped seal portion 54 is formed. An annular gasket 5 formed by bending a plate is fitted into a screw neck 59 between the mounting screw portion 52 and the seal portion 54. When the spark plug 100 is attached to the engine head 200, the gasket 5 is crushed and deformed between the seat surface 55 of the seal portion 54 and the opening peripheral edge portion 205 of the attachment screw hole 201. Due to the deformation of the gasket 5, the space between the spark plug 100 and the engine head 200 is sealed, and airtight leakage in the internal combustion engine through the mounting screw hole 201 is prevented.

  A thin caulking portion 53 is provided on the rear end side of the metal fitting 50 from the tool engaging portion 51. In addition, a thin compression deformation portion 58 is provided between the seal portion 54 and the tool engagement portion 51 as in the caulking portion 53. Between the inner peripheral surface of the metal shell 50 from the tool engaging portion 51 to the caulking portion 53 and the outer peripheral surface of the rear end side body portion 18 of the insulator 10, the first wire packing 6 and the second wire The packing 7 is interposed. A talc (talc) 9 is filled between the first wire packing 6 and the second wire packing 7. Each of the first wire packing 6 and the second wire packing 7 corresponds to an “annular member” in the claims, and is formed by processing a circular wire-shaped metal member into an annular shape. Yes. Hereinafter, a portion where the first wire packing 6, the second wire packing 7, and the talc 9 are arranged is referred to as a rear end side annular member arrangement portion 62. The rear end side annular member arrangement portion 62 is formed between the outer peripheral surface of the insulator 10 and the inner peripheral surface of the metal shell 50. The rear end side annular member arrangement portion 62 corresponds to the “annular member arrangement portion” in claim 4 at the beginning of the application.

  At the time of manufacturing the spark plug 100, the compression deforming portion 58 is compressed and deformed by pressing the crimping portion 53 inward so as to be bent inward, and the compression deformation of the compression deforming portion 58 causes the second wire packing. 7, the talc 9, and the first wire packing 6, the insulator 10 is pressed toward the front end side in the metal shell 50. By this pressing, the second step portion 15 of the insulator 10 is pressed through the plate packing 8 to the first step portion 56 formed at the position of the mounting screw portion 52 on the inner periphery of the metal shell 50, The metal shell 50 and the insulator 10 are integrated. At this time, the airtightness between the metal shell 50 and the insulator 10 is maintained by the plate packing 8, and the outflow of combustion gas is prevented. Further, by this pressing, the talc 9 is compressed in the axial direction OD direction, and the airtightness in the metal shell 50 is enhanced. The plate packing 8 corresponds to the “annular member” in the claims together with the first wire packing 6 and the second wire packing 7. The plate packing 8 is formed by processing a plate-shaped metal member into an annular shape. Hereinafter, the portion where the plate packing 8 is disposed is referred to as a distal end side annular member disposing portion 61. The front end side annular member arrangement portion 61 is formed between the outer peripheral surface of the insulator 10 and the inner peripheral surface of the metal shell 50. This front end side annular member arrangement portion 61 corresponds to the “annular member arrangement portion” in claim 5 at the beginning of the application. In the following description, the first wire packing 6, the second wire packing 7, and the plate packing 8 are collectively referred to as “annular members”, and the front-end-side annular member placement portion 61 and the rear-end-side annular member placement. The portion 62 may be collectively referred to as “annular member arrangement portion”.

  The center electrode 20 is mainly made of copper or copper having higher thermal conductivity than the electrode base material 21 inside the electrode base material 21 made of nickel or an alloy containing nickel as a main component, such as Inconel (trade name) 600. It is a rod-shaped electrode having a structure in which a core material 25 made of an alloy as a component is embedded. The center electrode 20 is produced by filling a core material 25 inside an electrode base material 21 formed in a bottomed cylindrical shape, and performing extrusion molding from the bottom side and stretching. The core member 25 has a substantially constant outer diameter at the body portion, but is formed in a tapered shape at the distal end side. The tip portion of the center electrode 20 is formed in a tapered shape having a smaller diameter toward the tip. An electrode tip 90 is joined to the tip of the tapered portion. The electrode tip 90 is formed with a high melting point noble metal as a main component in order to improve spark wear resistance. The electrode tip 90 is made of, for example, iridium (Ir) or an Ir alloy containing Ir as a main component.

  The center electrode 20 extends in the shaft hole 12 toward the rear end side, and is electrically connected to the rear terminal fitting 40 via the seal body 4 and the ceramic resistor 3. A high voltage cable (not shown) is connected to the terminal fitting 40 via a plug cap (not shown), and a high voltage is applied.

  The ground electrode 30 is formed of a metal having high corrosion resistance, and a nickel alloy is used as an example. The proximal end of the ground electrode 30 is welded to the distal end surface of the metal shell 50. The tip of the ground electrode 30 is bent so as to face the electrode tip 90 of the center electrode 20 on the axis O. A spark gap is formed between the tip of the ground electrode 30 and the tip of the electrode tip 90.

B. Spark plug manufacturing method:
FIG. 2 is a flowchart of a method for manufacturing a spark plug as one embodiment of the present invention. In the present embodiment, first, a metal shell 50 to which the ground electrode 30 is bonded in advance is prepared, and the plate packing 8 is arranged on the distal end side annular member arrangement portion 61 in the metal shell 50 (step S100).

  FIG. 3 is a view showing a method of arranging the plate packing 8 in the distal end side annular member arrangement portion 61. In the present embodiment, the plate packing 8 is arranged on the distal end side annular member arrangement portion 61 using the plate packing arrangement device 300. The plate packing arrangement device 300 includes a shutter 301, an insertion jig 302, a guide bar 303, and a position detector 307.

  The shutter 301 is a device having a mechanism that opens and closes in a horizontal direction (a direction perpendicular to the axial direction OD). The plate packing 8 is supplied to the upper surface of the shutter 301 (the surface on the rear end side in the axial direction OD) one by one from the horizontal direction when the shutter 301 is closed. A recess 304 into which the plate packing 8 supplied from the horizontal direction is fitted is formed on the upper surface of the shutter 301. When the plate packing 8 is disposed in the recess 304 when the shutter 301 is closed, the plate packing 8 and the insertion jig 302 described later are aligned in the radial direction.

  The insertion jig 302 is a cylindrical member disposed on the rear end side in the axial direction OD of the shutter 301 when the plate packing 8 is supplied to the upper surface of the shutter 301. When the plate packing 8 is supplied to the upper surface of the shutter 301, a gap is secured between the insertion jig 302 and the shutter 301 so that only one plate packing 8 is fitted. In the present embodiment, the insertion jig 302 is made of an austenitic stainless material. Since the austenitic stainless steel material is a non-magnetic material, the plate packing 8 formed of a magnetic material (for example, SWMGS-2 material) can be prevented from being magnetized. When the shutter 301 is opened in the horizontal direction, the plate packing 8 supplied onto the shutter 301 and the insertion jig 302 disposed vertically above (in the direction of the rear end side of the axial direction OD) are vertically downward (axis line). It falls freely by its own weight on the tip side in the direction OD.

  The guide rod 303 is a member disposed in a portion surrounded by the inner peripheral surface of the cylindrical insertion jig 302, and is a rod-like member extending in the axial direction OD. The guide bar 303 can move in the vertical direction along the axial direction OD. An opening 306 is provided at the center of the shutter 301, and the guide rod 303 can move along the axial direction OD through the opening 306 even when the shutter 301 is closed.

  The position detector 307 is a device that detects the position where the plate packing 8 is disposed by detecting the position of the insertion jig 302 in the axial direction OD. The position detector 307 may be constituted by a contact-type displacement sensor or a contact-type displacement sensor.

  In step S100, first, as shown in FIG. 3A, one plate packing 8 is supplied to the recess 304 formed in the upper surface of the shutter 301 of the plate packing arrangement device 300. By supplying the plate packing 8 to the recess 304 of the shutter 301, the radial alignment between the plate packing 8 and the insertion jig 302 is performed. When the plate packing 8 is supplied to the recess 304 of the shutter 301, the plate packing placement device 300 moves the guide rod 303 vertically downward (axis line) through the opening 306 of the shutter 301, as shown in FIG. The guide rod 303 is made to reach the vicinity of the front end side annular member arrangement portion 61 in the metal shell 50. The metal shell 50 is positioned in advance so that the central axis thereof coincides with the central axis of the guide rod 303. When the guide rod 303 reaches the vicinity of the distal end side annular member arrangement portion 61, the plate packing arrangement device 300 opens the shutter 301, as shown in FIG. Then, the plate packing 8 and the insertion jig 302 are freely dropped along the guide bar 303. Thus, when the plate packing 8 and the insertion jig 302 are freely dropped, the plate packing 8 is pushed into the distal end side annular member arrangement portion 61 by the weight of the insertion jig 302 and arranged. The step shown in FIG. 3C, that is, the step of arranging the plate packing 8 along the axial direction OD on the distal end side annular member arrangement portion 61 by using the insertion jig 302, This corresponds to the “first step” in the range.

  When the plate packing 8 is arranged in the distal end side annular member arrangement portion 61 as described above, the plate packing arrangement device 300 detects the position where the plate packing 8 is arranged using the position detector 307 (FIG. 2). Step S110). If the detected position is not the position of the predetermined front end side annular member arrangement portion 61 (step S120: NG), the plate packing arrangement device 300 determines that the spark plug 100 being manufactured is a manufacturing defect, and Production of the plug 100 is stopped. On the other hand, if the detected position is the position of the predetermined front end side annular member placement portion 61 (step S120: OK), the plate packing 8 is accurately placed on the front end side annular member placement portion 61. Will be. Therefore, subsequently, the insulator 10 in which the terminal fitting 40, the ceramic resistor 3, the seal body 4, and the center electrode 20 are assembled is inserted into the insertion hole 501 of the metal shell 50 from the rear end side (step S130). . Then, the plate packing 8 disposed in the distal end side annular member disposing portion 61 in step S100 is interposed between the second step portion 15 of the insulator 10 and the first step portion 56 of the metal shell 50. become.

  When the insulator 10 is inserted into the metal shell 50, the first wire packing 6 is subsequently placed on the rear end side annular member placement portion 62 (step S140).

  FIG. 4 is a view showing a method of arranging the first wire packing 6 in the rear end side annular member arrangement portion 62. In the present embodiment, the first wire packing 6 is placed on the rear end side annular member placement portion 62 using the wire packing placement device 400. The line packing arrangement device 400 includes a shutter 401, an insertion jig 402, a holding jig 403, and a position detector 407.

  The shutter 401 is a device having a mechanism that opens and closes in a horizontal direction (a direction perpendicular to the axial direction OD). The first wire packing 6 is supplied to the upper surface of the shutter 401 (the surface on the rear end side in the axial direction OD) one by one from the horizontal direction when the shutter 401 is closed. On the upper surface of the shutter 401, a recess 404 into which the first wire packing 6 supplied from the horizontal direction is fitted is formed. When the shutter 401 is closed, the first wire packing 6 is disposed in the depression 404, so that the first wire packing 6 and an insertion jig 402 described later are aligned in the radial direction.

  The insertion jig 402 is a cylindrical member disposed on the rear end side in the axial direction OD of the shutter 401 when the first wire packing 6 is supplied to the upper surface of the shutter 401. When the first wire packing 6 is supplied to the upper surface of the shutter 401, a gap is secured between the insertion jig 402 and the shutter 401 so that only one first wire packing 6 is fitted. In the present embodiment, the insertion jig 402 is formed of an austenitic stainless material. Since the austenitic stainless material is a non-magnetic material, the first wire packing 6 formed of a magnetic material (for example, SWMGS-2 material) can be prevented from being magnetized. When the shutter 401 is opened in the horizontal direction, the first wire packing 6 supplied on the shutter 401 and the insertion jig 402 disposed vertically above (in the direction of the rear end side in the axial direction OD) are vertically aligned. It falls freely by its own weight downward (direction on the tip side of the axial direction OD).

  The holding jig 403 is a member disposed in a portion surrounded by the inner peripheral surface of the cylindrical insertion jig 402, and is a rod-like member extending in the axial direction OD. The holding jig 403 can move in the vertical direction along the axial direction OD. A recess 408 is formed at the tip of the holding jig 403. The concave portion 408 contacts the rear end of the terminal fitting 40 when the holding jig 403 moves vertically downward. An opening 406 is provided at the center of the shutter 401. Even when the shutter 401 is closed, the holding jig 403 can freely move along the axial direction OD through the opening 406.

  The position detector 407 is a device that detects the position where the first wire packing 6 (or the second wire packing 7) is arranged by detecting the position of the insertion jig 402 in the axial direction OD. The position detector 407 may be constituted by a contact-type displacement sensor or a contact-type displacement sensor.

  In step S140, first, as shown in FIG. 4A, one first wire packing 6 is supplied to the depression 404 formed on the upper surface of the shutter 401. By supplying the first wire packing 6 to the recess 404 of the shutter 401, the radial alignment between the first wire packing 6 and the insertion jig 402 is performed. When the first wire packing 6 is supplied to the recess 404 of the shutter 401, the wire packing placement device 400 moves the holding jig 403 through the opening 406 of the shutter 401 as shown in FIG. The rear end of the terminal fitting 40 is pressed by the concave portion 408 at the front end of the holding jig 403. By doing so, the radial position of the insulator 10 is fixed. At this time, the metal shell 50 is positioned in advance so that the central axis thereof coincides with the central axis of the holding jig 403. When the insulator 10 is fixed by the holding jig 403, the wire packing placement device 400 opens the shutter 401 as shown in FIG. Then, the first wire packing 6 and the insertion jig 402 freely fall along the holding jig 403 and the insulator 10. Thus, when the first wire packing 6 and the insertion jig 402 are freely dropped, the first wire packing 6 is pushed into the rear end side annular member arrangement portion 62 by the weight of the insertion jig 402 and arranged. . The process shown in FIG. 4C, that is, the process in which the first wire packing 6 is arranged in the rear end side annular member arrangement portion 62 along the axial direction OD by using the insertion jig 402 is as follows. Similarly to the process shown in FIG. 3C, this corresponds to the “first process” in the claims.

  When the first line packing 6 is arranged in the rear end side annular member arrangement portion 62 as described above, the line packing arrangement apparatus 400 uses the position detector 407 to arrange the first line packing 6. The position is detected (step S150 in FIG. 2). If the detected position is not a position in the predetermined rear end side annular member arrangement portion 62 (step S160: NG), the line packing arrangement device 400 determines that the spark plug 100 being manufactured is a manufacturing defect. The production of the spark plug 100 is stopped. On the other hand, if the detected position is a position within the predetermined rear end side annular member arrangement portion 62 (step S160: OK), the first wire packing 6 is accurately positioned at the front end side annular member. It will be arranged in the part 61. Therefore, subsequently, talc is filled in the rear end side annular member arrangement portion 62 (step S170).

  When talc is filled in the rear end side annular member arrangement part 62, the second wire packing 7 is arranged in the rear end side annular member arrangement part 62 (step S180). The 2nd wire packing 7 is arrange | positioned in the rear end side annular member arrangement | positioning part 62 by the method and apparatus similar to the method shown in FIG. When the second line packing 7 is arranged in the rear end side annular member arrangement portion 62, the position where the second line packing 7 is arranged is detected by the position detector 407 (step S190). If the detected position is not a position in the predetermined rear end side annular member arrangement portion 62 (step S200: NG), it is determined that the spark plug 100 being manufactured is defective in manufacture, and the spark plug 100 is manufactured. Stopped. On the other hand, if the detected position is a position within the predetermined rear end side annular member arrangement portion 62 (step S200: OK), the second wire packing 7 is accurately positioned at the rear end side annular member. It is arranged in the arrangement part 62. Then, the caulking process is subsequently performed on the rear end of the metal shell 50 (step S210), and the gasket 5 is attached (step S220). The spark plug 100 is completed through the series of manufacturing steps described above.

  In the manufacturing method of the spark plug 100 of the present embodiment described above, the annular members 6, 7, and 8 (the first wire packing 6, the second wire packing 7, and the plate packing 8) are annular member arrangement portions. 61 and 62 (the front end side annular member arrangement portion 61 and the rear end side annular member arrangement portion 62) are inserted along the axial direction OD by the insertion jigs 302 and 304. Therefore, the annular members 6, 7, and 8 are suppressed from being caught by the insulator 10, the metal shell 50, or the terminal metal fitting 40. As a result, the annular members 6, 7, and 8 can be accurately arranged on the annular member arrangement portions 61 and 62.

  In the present embodiment, the annular members 6, 7, 8 are inserted into the annular member placement portions 61, 62 by the weight of the insertion jigs 302, 402. Therefore, even if the annular members 6, 7, 8 are caught on the metal shell 50, the insulator 10, or the terminal fitting 40 for some reason, the insertion jigs 302, 402 bite into the annular members 6, 7, 8. Can be suppressed. As a result, for example, cracking of the insulator 10 and deformation of the annular members 6, 7, and 8 can be suppressed.

  In the present embodiment, before the annular members 6, 7, 8 are actually arranged with respect to the annular member arrangement portions 61, 62, the surfaces of the shutters 301, 401 on the rear end side of the axial direction OD are arranged. By supplying the annular members 6, 7, 8 to the formed depressions 304, 404, the radial alignment between the annular members 6, 7, 8 and the insertion jigs 302, 402 is performed. Therefore, the annular members 6, 7, and 8 can be more accurately arranged in the annular member arrangement portions 61 and 62.

  Further, in the present embodiment, when the first wire packing 6 and the second wire packing 7 are arranged with respect to the rear end side annular member arrangement portion 62, the holding jig 403 is used along the axial direction OD. With the terminal fitting 40 held, the first wire packing 6 and the second wire packing 7 are inserted into the rear end side annular member arrangement portion 62. Therefore, it can suppress that the insulator 10 inclines and that the 1st wire packing 6 and the 2nd wire packing 7 are caught in the rear-end surface of the terminal metal fitting 40. FIG. Therefore, the first wire packing 6 and the second wire packing 7 can be more accurately arranged in the rear end side annular member arrangement portion 62.

  Further, in the present embodiment, when the plate packing 8 is disposed with respect to the distal end side annular member placement portion 61, the guide rod 303 is moved to the vicinity of the distal end side annular member placement portion 61 in the metal shell 50. Since the plate packing 8 is inserted, the plate packing 8 is prevented from being caught on the side wall in the metal shell 50. Therefore, the plate packing 8 can be more accurately arranged at the distal end side annular member arrangement portion 61.

  In the present embodiment, the positions of the annular members 6, 7, 8 are detected by detecting the positions of the insertion jigs 302, 402 using the position detectors 307, 407. Therefore, it is possible to accurately detect whether or not the annular members 6, 7, and 8 are arranged in the annular member arrangement portions 61 and 62.

  In the present embodiment, the insertion jigs 302 and 402 are made of an austenitic stainless material. Since the austenitic stainless material is a nonmagnetic material, the annular members 6, 7, 8 can be prevented from being magnetized by the insertion jigs 302, 402. Therefore, the annular members 6, 7, 8 are suppressed from being attracted to the insertion jigs 302, 402 by magnetic force, and the annular members 6, 7, 8 can be stably disposed on the annular member arrangement portions 61, 62. . The insertion jigs 302 and 402 are not limited to an austenitic stainless material, but are formed of other nonmagnetic materials or materials that can be demagnetized when magnetized (for example, carbon tool steel such as SK3). Also good.

C. Test results:
Various tests were performed on the manufacturing method of the spark plug 100 in the above-described embodiment. The results of these tests are shown below.

C-1. Wire packing placement test according to the presence or absence of an insertion jig:
Table 1 shows the result of the test in which the first wire packing 6 is simply dropped on the rear end side annular member placement portion 62 and the first wire packing 6 is freely dropped and the weight of the insertion jig 402 is The test result which inserted the 1st wire packing 6 in the rear end side annular member arrangement | positioning part 62 is shown. As the insertion jig 402, a jig formed of an austenitic stainless material, which is a nonmagnetic material, was used.

  In this test, 10,000 spark plugs 100 were manufactured, and it was evaluated whether or not the first wire packing 6 was caught in 20 or more spark plugs 100 at that time. As a result, when the first wire packing 6 is disposed in the rear end side annular member disposing portion 62 only by free fall, the first wire packing 6 is caught by the 20 or more spark plugs 100, and insertion treatment is performed. When the tool 402 was used, the catch of the first wire packing 6 was less than 20. Therefore, the first wire packing 6 is placed on the rear end side annular member placement portion 62 by using the insertion jig 402 rather than the first wire packing 6 placed on the rear end side annular member placement portion 62 only by free fall. It has been confirmed that the first wire packing 6 can be accurately placed on the rear end side annular member placement portion 62 when placed.

  In addition, since the 2nd wire packing 7 is also arrange | positioned in the rear end side annular member arrangement | positioning part 62 by the method similar to the 1st wire packing 6, the insertion jig | tool 402 is used also about the 2nd wire packing 7. FIG. Thereby, it can arrange | position to the rear end side annular member arrangement | positioning part 62 exactly. Further, since the plate packing 8 is also arranged in the distal end side annular member arrangement portion 61 by the same method as the first wire packing 6, the plate packing 8 is also used by using the insertion jig 302, so It is possible to accurately arrange the annular member arrangement portion 61.

C-2. Wire packing placement test according to the presence or absence of a holding jig:
Table 2 shows a test result in which the first wire packing 6 is arranged in the rear end side annular member arranging portion 62 without holding the terminal fitting 40 by the holding jig 403, and the terminal fitting 40 is held by the holding jig 403. The test result which has arrange | positioned the 1st wire packing 6 in the rear end side annular member arrangement | positioning part 62 in the state which showed is shown. In this test, the first wire packing 6 was placed on the rear end side annular member placement portion 62 using the insertion jig 402. Moreover, as the insertion jig 402, the thing formed with the austenitic stainless material which is a nonmagnetic material was used.

  In this test, 10,000 spark plugs 100 were manufactured, and at that time, it was evaluated whether or not the first wire packing 6 was caught when 20 or more spark plugs 100 were manufactured. As a result, when the terminal fitting 40 is not pressed by the holding jig 403, the first wire packing 6 is caught by 20 or more spark plugs 100, and when the terminal fitting 40 is pressed by the holding jig 403. The number of hooks of the first wire packing 6 was less than 20. Therefore, rather than not using the holding jig 403, the first wire packing 6 is more accurately attached to the rear end side annular member arrangement portion 62 when the terminal fitting 40 is pressed in the axial direction OD using the holding jig 403. It was confirmed that it could be placed.

  Since the second wire packing 7 is also arranged in the rear end side annular member arrangement portion 62 by the same method as the first wire packing 6, the holding jig 403 is also used for the second wire packing 7. Thereby, it can arrange | position to the rear end side annular member arrangement | positioning part 62 exactly.

C-3. Wire packing placement test according to the operation of the insertion jig:
Table 3 shows a test result in which the first wire packing 6 is arranged on the rear end side annular member arrangement portion 62 by its own weight (100 gf) of the insertion jig 402, and a predetermined load (1 kgf) is applied to the insertion jig 402. The test result which has arrange | positioned the annular member 6 in the rear end side annular member arrangement | positioning part 62 is shown by forcibly moving.

  In this test, the insertion jig 402 was moved in the axial direction OD direction in a state where the first wire packing 6 was hooked in advance on a constriction 65 (see FIG. 1) formed on the side surface of the terminal fitting 40. As a result, when the insertion jig 402 was moved (dropped) by its own weight, the insertion jig 402 did not bite into the first wire packing 6. On the other hand, when the insertion jig 402 is forcibly moved, the insertion jig 402 bites into the first wire packing 6. Thus, if the insertion jig 402 bites into the first wire packing 6, it causes a problem such as cracking of the insulator 10 and deformation of the wire packings 6 and 7. For this reason, it has been confirmed that the insertion jig 402 can suppress the inconvenience when it is freely dropped by its own weight rather than forcibly moving it.

C-4. Evaluation test according to the material of the insertion jig:
Table 4 shows the results of preparing insertion jigs 402 of various materials and arranging the first wire packing 6 in the rear end side annular member arrangement portion 62 using the insertion jigs 402.

  In this test, 10,000 spark plugs 100 were manufactured, and at that time, it was evaluated whether or not the first wire packing 6 could be accurately placed on the rear end side annular member placement portion 62. As a result, when the insertion jig 402 formed using austenitic stainless steel SUS304, which is a non-magnetic material, is used, the first wire packing 6 is accurately supplied to 5000 or more spark plugs 100. I was able to. In contrast, it is made of a material such as SUS410, which is a martensitic stainless material, which is a magnetic material (ferromagnetic material), SUS630, S45C (carbon steel for machine structural use), or SKS3 (alloy tool steel), which is a precipitation hardening stainless material. When the inserted jig 402 was used, the number of spark plugs 100 that could accurately supply the first wire packing 6 was less than 5000. This is presumably because the insertion jig 402 formed of a magnetic material is magnetized by the movement of the insertion jig 402 and the first wire packing 6 is magnetically attracted to the insertion jig 402. Therefore, it was confirmed that the insertion jig 402 is preferably made of a non-magnetic material. Note that the insertion jig 302 is also preferably made of a non-magnetic material for the same reason.

C-5. Plate packing placement test:
Table 5 shows the presence or absence of the insertion jig 302 and the guide rod 303 for the insertion jig 302 formed of a magnetic body (S45C) and the insertion jig 302 formed of a non-magnetic body (SUS304). The test result which evaluated the supply property of the board packing 8 by changing the presence or absence of this is shown.

  In this test, when 1000 spark plugs 100 were manufactured, it was evaluated whether or not the plate packing 8 could be accurately placed on the distal end side annular member placement portion 61. As a result, for any of the insertion jigs 302 formed of a magnetic material and a non-magnetic material, the plate packing 8 is attached to the distal end side annular member placement portion 61 by using the insertion jig 302 rather than merely dropping the plate packing 8 freely. It was confirmed that the inserted plate can arrange the plate packing 8 accurately. Further, not only using the insertion jig 302, but also dropping the plate packing 8 and the insertion jig 302 along the guide bar 303 more accurately causes the tip of the plate packing 8 to be used than when the guide bar 303 is not used. It was confirmed that it can be arranged in the side annular member arrangement part 61. Further, it was confirmed that the material of the insertion jig 302 can be more accurately placed on the distal end side annular member placement portion 61 when a non-magnetic material is used than a magnetic material.

  As shown in the various test results shown above, according to the method for manufacturing the spark plug 100 of the present embodiment, an annular member such as the wire packings 6 and 7 and the plate packing 8 is replaced with a predetermined portion (annular member) of the spark plug 100. It is possible to accurately arrange in the arrangement portions 61 and 62).

D. Variations:
In the above embodiment, the annular members 6, 7, and 8 may not be completely formed as “rings”. For example, a part of the annular members 6, 7, 8 may be cut.

  In the above embodiment, when talc is filled in the rear end side annular member arrangement portion 62, solid talc called a talc ring is rear end side annular by the same method as the annular members 6, 7, and 8. You may arrange | position to the member arrangement | positioning part 62. FIG. The talc ring is crushed into powder when the metal shell 50 is crimped.

  In the above embodiment, the annular members 6, 7, and 8 are arranged using the guide rod 303 and the holding jig 403. However, the annular members 6, 7, and 8 may be arranged without using the guide rod 303 or the holding jig 403.

  In the above embodiment, the annular members 6, 7, and 8 are inserted into the annular member placement portions 61 and 62 by the weight of the insertion jigs 302 and 402. On the other hand, a load may be applied to the insertion jigs 302 and 402 to the extent that the annular members 6, 7, and 8 are not deformed, and the annular members 6, 7, and 8 may be pushed into the annular member placement portions 61 and 62.

  The present invention is not limited to the above-described embodiments, examples, and modifications, and can be realized with various configurations without departing from the spirit thereof. For example, the technical features in the embodiments, examples, and modifications corresponding to the technical features in each embodiment described in the summary section of the invention are to solve some or all of the above-described problems, or In order to achieve part or all of the above effects, replacement or combination can be performed as appropriate. Further, if the technical feature is not described as essential in the present specification, it can be deleted as appropriate.

DESCRIPTION OF SYMBOLS 3 ... Ceramic resistance 4 ... Sealing body 5 ... Gasket 6 ... 1st wire packing 7 ... 2nd wire packing 8 ... Plate packing 9 ... Talc 10 ... Insulator 12 ... Shaft hole 13 ... Leg long part 15 ... 2nd step Part 17: Front end side body part 18 ... Rear end side body part 19 ... Gutter part 20 ... Center electrode 21 ... Electrode base material 25 ... Core material 30 ... Ground electrode 40 ... Terminal metal fitting 50 ... Main metal fitting 51 ... Tool engagement part 52 ... Mounting screw part 53 ... Clamping part 54 ... Sealing part 55 ... Seat surface 56 ... First step part 58 ... Compression deformation part 59 ... Screw neck 61 ... Front end side annular member arrangement part 62 ... Rear end side annular member arrangement part 65 ... Constriction 90 ... Electrode tip 100 ... Spark plug 200 ... Engine head 201 ... Mounting screw hole 205 ... Opening peripheral edge 300 ... Plate packing arrangement device 301 ... Shutter 302 ... Inserting jig 303 ... Guide rod 304 ... Indentation 306 ... Opening 307 ... Position detector 400 ... Line packing placement device 401 ... Shutter 402 ... Insertion jig 403 ... Pressing jig 404 ... Dimple 406 ... Opening 407 ... Position detector 408 ... Recess 501 ... Insertion hole O ... Axis OD ... Axial direction

Claims (9)

A central electrode extending in the axial direction;
A cylindrical insulator disposed on the outer periphery of the center electrode;
A cylindrical metal shell disposed on the outer periphery of the insulator;
An annular member;
An annular member disposition portion formed between the outer peripheral surface of the insulator and the inner peripheral surface of the metal shell, and the annular member is disposed;
A spark plug manufacturing method comprising:
A first step of arranging the annular member in the annular member arrangement portion along the axial direction using an insertion jig ;
In the first step, the annular member is arranged in the annular member arrangement portion by the weight of the insertion jig . It is a manufacturing method of the spark plug according to claim 1 ,
Prior to the first step, when the shutter disposed closer to the distal end side in the axial direction than the distal end of the insertion jig is closed, the annular member is disposed on the surface on the rear end side in the axial direction of the shutter. , Radial alignment of the annular member and the insertion jig is performed,
In the first step, after the shutter is opened, the annular member is arranged on the annular member arrangement portion by the insertion jig. A method of manufacturing a spark plug according to claim 1 or claim 2 ,
The said annular member arrangement | positioning part is a part enclosed with the outer peripheral surface of the said insulator, and the inner peripheral surface of the rear-end part of the said main metal fitting, The manufacturing method of the spark plug characterized by the above-mentioned. A method of manufacturing a spark plug according to claim 1 or claim 2 ,
The annular member placement portion is provided on a first step provided on an inner peripheral surface of the metal shell and on an outer peripheral surface of the insulator, and the first member is inserted when the insulator is inserted into the metal shell. A method for manufacturing a spark plug, wherein the step is a portion between a second step portion and the second step portion. It is a manufacturing method of the spark plug according to claim 3 ,
The spark plug has a terminal fitting electrically connected to the center electrode at an end of the insulator,
In the first step, the annular member is arranged in the annular member arrangement portion using the insertion jig in a state where the terminal fitting is held along the axial direction using a holding jig. A method for manufacturing a spark plug. It is a manufacturing method of the spark plug according to claim 4 ,
The insertion jig is cylindrical, and a guide bar extending in the axial direction is provided in a portion surrounded by an inner peripheral surface of the insertion jig,
In the first step, the insertion jig is moved along the guide rod to dispose the annular member. A method for manufacturing a spark plug according to any one of claims 1 to 6 , further comprising:
A spark plug comprising: a step of determining whether or not the annular member is arranged in the annular member arrangement portion by detecting a position of the insertion jig in the axial direction using a detector. Production method. A method for producing a spark plug according to any one of claims 1 to 7 ,
The annular member is made of a magnetic material,
The method of manufacturing a spark plug, wherein the insertion jig is made of a nonmagnetic material or a material that can be demagnetized when magnetized. A method for producing a spark plug according to any one of claims 1 to 7 ,
The method for producing a spark plug, wherein the insertion jig is formed of an austenitic stainless material.

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