JP6066864B2 - 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 (see, for example, Patent Document 1). The insulator and the metal shell are fixed by crimping the rear end of the metal shell. An annular member called wire packing is disposed between the inner peripheral surface of the rear end portion of the metal shell and the outer peripheral surface of the insulator on the front end side of the portion to be crimped. Hereinafter, the portion where the wire packing is arranged in this way is referred to as “annular member arrangement portion”.

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

  Conventionally, the arrangement of the line packing in the annular member arrangement portion has been performed by allowing the line packing to fall freely from the rear end side of the insulator before the caulking process. If the wire packing is freely dropped, the wire packing may be caught by the corrugated corrugations formed on the insulator during the fall, which may cause a reduction in the manufacturing efficiency of the spark plug. Therefore, a technique that can accurately supply an annular member such as a wire packing to a predetermined portion of the spark plug has been demanded.

The present invention has been made to solve the above-described problems, and can be realized as the following forms.
The first aspect of the present invention is:
A central electrode extending in the axial direction;
A cylindrical insulator disposed on the outer periphery of the center electrode and having an uneven corrugation formed on the outer periphery on the rear end side;
A cylindrical metal shell disposed on the outer periphery of the insulator;
An annular member having a diameter larger than the maximum diameter of the insulator in the portion where the corrugation is formed;
An annular member disposition portion that is disposed on the front end side relative to the corrugation and is surrounded by an inner peripheral surface of a rear end portion of the metal shell and an outer peripheral surface of the insulator,
A spark plug manufacturing method comprising:
The annular member is allowed to pass through a portion where the corrugation is formed from the rear end side of the insulator while the annular member is in contact with a supply device for supplying the annular member to the annular member arrangement portion. The first step;
After the first step, the second step of releasing the contact between the supply device and the annular member and supplying the annular member to the annular member arrangement portion;
Have
In the second step, by releasing the contact between the supply device and the annular member, the annular member and the insertion jig disposed on the rear end side of the annular member are dropped, and the insertion jig The annular member is supplied to the annular member arrangement portion by its own weight. 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 having an uneven corrugation formed on the outer periphery on the rear end side; A cylindrical metal shell disposed on the outer periphery of the insulator; an annular member having a diameter larger than the maximum diameter of the insulator in a portion where the corrugation is formed; and disposed on the tip side of the corrugation And a spark plug manufacturing method comprising: an annular member arrangement portion surrounded by an inner peripheral surface of a rear end portion of the metal shell and an outer peripheral surface of the insulator. In this manufacturing method, the corrugation is formed from the rear end side of the insulator while the annular member is in contact with a supply device for supplying the annular member to the annular member arrangement portion. A first step of passing a portion that is present; and a second step of releasing the contact between the supply device and the annular member and supplying the annular member to the annular member arrangement portion after the first step. It is characterized by having. According to the spark plug manufacturing method of this aspect, the annular member passes through the portion where the corrugation is formed from the rear end side of the insulator while being in contact with the supply device, and then the contact with the supply device is released. And supplied to the annular member arrangement portion. Therefore, when supplying an annular member to an annular member arrangement part, it is controlled that an annular member gets caught in the back end part of an insulator, and corrugation. As a result, the annular member can be accurately arranged in the annular member arrangement portion.

(2) In the spark plug manufacturing method, the supply device has a mechanism for chucking the annular member. In the second step, after the first step, the supply device is chucked with the annular member. By releasing the contact, the contact between the supply device and the annular member may be released. With such a spark plug manufacturing method, the supply device can control the contact state with the annular member by opening and closing the chuck.

(3) In the spark plug manufacturing method, the supply device has a mechanism for adsorbing the annular member by sucking air, and in the second step, the supply device is provided with the supply device after the first step. The contact between the supply device and the annular member may be released by stopping the suction of air. With such a spark plug manufacturing method, the supply device can control the contact state with the annular member in accordance with whether or not air is sucked.

(4) In the spark plug manufacturing method, the supply device has a mechanism for adsorbing the annular member by magnetic force, and in the second step, the magnetic force is released to the supply device after the first step. By doing so, the contact between the supply device and the annular member may be released. With such a spark plug manufacturing method, the supply device can control the contact state with the annular member in accordance with whether or not the magnetic force is applied.

(5) In the spark plug manufacturing method, in the second step, after the contact between the supply device and the annular member is released, the annular member is placed on the annular member arrangement portion using an insertion jig. You may supply. If it is such a manufacturing method of a spark plug, an annular member can be accurately supplied to an annular member arrangement part by using an insertion jig.

(6) In the spark plug manufacturing method, the spark plug has a terminal fitting electrically connected to the center electrode at an end of the insulator, and in the second step, a holding jig is used. The annular member may be supplied to the annular member disposition portion in a state where the terminal fitting is pressed along the axial direction using the. With such a spark plug manufacturing method, the annular member is supplied 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 annular member may be formed of a magnetic material, and the supply device may be formed of a nonmagnetic material or a material that can be demagnetized when magnetized. If it is such a manufacturing method of a spark plug, since it can suppress that an annular member is magnetized by a supply device, an annular member can be arranged in an annular member arrangement part stably.

(8) In the spark plug manufacturing method, the supply device may be formed of an austenitic stainless material. Since the austenitic stainless steel material is a non-magnetic material, it is possible to suppress the annular member from being magnetized by the supply device 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 wire packing to an annular member arrangement | positioning part. It is a figure which shows the method of arrange | positioning wire packing to an 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. An uneven corrugation 11 is formed on the outer periphery of the rear end side body portion 18.

  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 crimping portion 53 and the outer peripheral surface of the rear end side body portion 18 of the insulator 10, the annular first wire packing 6 and the second wire packing 6 are provided. The wire packing 7 is interposed. A talc (talc) 9 is filled between the first wire packing 6 and the second wire packing 7. Both the first wire packing 6 and the second wire packing 7 correspond to “annular members” in the claims. The 1st wire packing 6 and the 2nd wire packing 7 are formed by processing a circular wire-shaped metal member cyclically | annularly. The diameters of the first wire packing 6 and the second wire packing 7 are larger than the maximum diameter of the portion where the corrugation 11 is formed. Hereinafter, a portion where the first wire packing 6, the second wire packing 7, and the talc 9 are arranged is referred to as an annular member arrangement portion 62. The 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.

  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 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, 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 via the plate packing 8. Is inserted from the side (step S100).

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

  3 and 4 are diagrams showing a method of arranging the first wire packing 6 in the annular member arrangement portion 62. FIG. In the present embodiment, the first wire packing 6 is arranged on the annular member arrangement portion 62 using the wire packing supply device 400. The wire packing supply device 400 includes a chuck mechanism 401, an insertion jig 402, and a holding jig 403.

  The chuck mechanism 401 is a device that can be opened and closed in a horizontal direction (a direction perpendicular to the axial direction OD), and holds (chucks) the first wire packing 6 from its side surface. A recess 404 into which the first wire packing 6 supplied from the horizontal direction is fitted is formed on the upper surface of the chuck mechanism 401 (the surface on the rear end side in the axial direction OD). When the first wire packing 6 is supplied to the recess 404 from the horizontal direction, the first wire packing 6 is held and held by the chuck mechanism 401. The first wire packing 6 is disposed in the recess 404 and is held by the chuck mechanism 401, whereby the radial alignment between the first wire packing 6 and an insertion jig 402 described later is performed.

  The insertion jig 402 is a cylindrical member disposed on the rear end side in the axial direction OD of the chuck mechanism 401 when the first wire packing 6 is supplied to the upper surface of the chuck mechanism 401. When the first wire packing 6 is supplied to the upper surface of the chuck mechanism 401, a gap is secured between the insertion jig 402 and the chuck mechanism 401 so that only one first wire packing 6 is fitted. Yes. When the above-described chuck mechanism 401 opens in the horizontal direction, the first wire packing 6 supplied to the chuck mechanism 401 and the insertion jig 402 arranged vertically above (in the direction of the rear end side in the axial direction OD) are arranged. It falls freely by its own weight vertically 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 chuck mechanism 401, and the pressing jig 403 can move along the axial direction OD through the opening 406 even when the chuck mechanism 401 is closed.

  In the present embodiment, at least the chuck mechanism 401 and the insertion jig 402 in the wire packing supply device 400 are 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.

  In step S110, first, as shown in FIG. 3A, one first wire packing 6 is supplied to the depression 404 formed on the upper surface of the chuck mechanism 401. Then, the first wire packing 6 is held by the chuck mechanism 401 of the wire packing supply device 400, and the wire packing supply device 400 and the first wire packing 6 are in contact with each other. When the first wire packing 6 is supplied to the chuck mechanism 401, the wire packing supply device 400 vertically moves the holding jig 403 through the opening 406 of the chuck mechanism 401 as shown in FIG. Move downward (direction on the tip side of the axial direction OD). Then, the terminal fitting 40 is pressed by the recess 408 at the tip of the holding jig 403, and the radial position of the insulator 10 is fixed. The metal shell 50 in which the insulator 10 is inserted 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 supply device 400 holds the first wire packing 6 with the chuck mechanism 401 as shown in FIG. 1 wire packing 6 is moved along the holding jig 403 toward the tip end side in the axial direction OD. By doing so, the wire packing supply device 400 allows the first wire packing 6 to pass through the portion where the corrugation 11 is formed from the rear end side of the insulator 10. The process shown in FIG. 4A, that is, the process of passing the first wire packing 6 through the corrugation 11 portion while the wire packing supply device 400 and the first wire packing 6 are in contact with each other is claimed. This corresponds to the “first step” in the range. When the first wire packing 6 is moved along the holding jig 403 toward the distal end side in the axial direction OD, the insertion jig 402 is also moved along the holding jig 403 toward the distal end side in the axial direction OD.

  When the first wire packing 6 passes through the portion where the corrugation 11 is formed, the wire packing supply device 400 opens the chuck mechanism 401 as shown in FIG. The contact between the device 400 and the first wire packing 6 is released. Then, the first wire packing 6 and the insertion jig 402 freely fall along a portion on the tip side of the portion where the corrugation 11 of the insulator 10 is formed. Thus, when the first wire packing 6 and the insertion jig 402 are freely dropped, the first wire packing 6 is pushed into the annular member placement portion 62 by the dead weight of the insertion jig 402. The process shown in FIG. 4B, that is, the process of releasing the contact between the wire packing supply device 400 and the first wire packing 6 and supplying the first wire packing 6 to the annular member arrangement portion 62, This corresponds to the “second step” in the claims.

  When the first wire packing 6 is arranged in the annular member arrangement part 62 as described above, talc is subsequently filled in the annular member arrangement part 62 (step S120 in FIG. 2). When the annular member placement portion 62 is filled with talc, the second wire packing 7 is placed in the annular member placement portion 62 (step S130). The 2nd wire packing 7 is arrange | positioned in the annular member arrangement | positioning part 62 by the method and apparatus similar to the method shown to FIG. 3 and FIG. When the second wire packing 7 is arranged in the annular member arrangement portion 62, the rear end of the metal shell 50 is subjected to crimping (step S140), and the gasket 5 is further attached (step S150). ). 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 corrugations 11 are formed from the rear end side of the insulator 10 while the wire packings 6 and 7 are in contact with the chuck mechanism 401 of the wire packing supply device 400. After that, the contact with the chuck mechanism 401 is released and supplied to the annular member arrangement portion 62. Therefore, when the wire packings 6 and 7 are arranged in the annular member arrangement portion 62, the wire packings 6 and 7 are prevented from being caught by the corrugation 11 of the insulator 10, the constriction 65 (see FIG. 1) of the terminal fitting 40, or the like. Is done. As a result, the wire packings 6 and 7 can be accurately placed on the annular member placement portion 62.

  Further, in this embodiment, after the contact between the wire packings 6 and 7 and the chuck mechanism 401 is released, the wire packings 6 and 7 are supplied by being pushed into the annular member arrangement portion 62 by the weight of the insertion jig 402. Is done. Therefore, the wire packings 6 and 7 are stably supplied to the annular member arrangement portion 62 without being caught between the outer peripheral surface of the insulator 10 and the inner peripheral surface of the metal shell 50.

  In the present embodiment, the wire packings 6 and 7 are supplied to the annular member arrangement portion 62 in a state where the terminal fitting 40 is pressed along the axial direction OD using the holding jig 403. Therefore, it can suppress that the insulator 10 inclines and that the wire packings 6 and 7 are caught by the rear-end surface of the terminal metal fitting 40. FIG. Therefore, the wire packings 6 and 7 can be more accurately arranged on the annular member arrangement portion 62.

  In the present embodiment, at least the chuck mechanism 401 and the insertion jig 402 of the wire packing supply device 400 are formed of an austenitic stainless material. Since the austenitic stainless material is a non-magnetic material, the wire packings 6 and 7 can be prevented from being magnetized by the chuck mechanism 401 and the insertion jig 402. Therefore, the wire packings 6 and 7 are suppressed from being attracted to the chuck mechanism 401 and the insertion jig 402 by a magnetic force, and the wire packings 6 and 7 can be stably arranged on the annular member arrangement portion 62. Note that at least the chuck mechanism 401 and the insertion jig 402 in the wire packing supply device 400 are not limited to austenitic stainless materials, but other nonmagnetic materials, or materials that can be demagnetized when magnetized (for example, SK3). Or carbon tool steel).

  In the above-described embodiment, the wire packing supply device 400 holds the wire packings 6 and 7 by the chuck mechanism 401. On the other hand, for example, in another embodiment, a mechanism for adsorbing the wire packings 6 and 7 by sucking air may be employed. In this case, the wire packing supply device 400 stops the suction of the air, thereby releasing the contact between the wire packings 6 and 7 and the wire packing supply device 400, so that the wire packings 6 and 7 are connected to the annular member arranging portion 62. To supply. In still another embodiment, a mechanism for adsorbing the wire packings 6 and 7 by magnetic force may be employed. In this case, the wire packing supply device 400 releases the magnetic force, thereby releasing the contact between the wire packings 6 and 7 and the wire packing supply device 400, and supplies the wire packings 6 and 7 to the annular member arrangement portion 62. To do.

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 chuck release time:
Table 1 shows that the contact between the chuck mechanism 401 and the first wire packing 6 is released before the first wire packing 6 passes through the corrugation 11 of the insulator 10, and the first wire packing 6 is disposed in an annular member. The test results supplied to the unit 62 and the contact between the chuck mechanism 401 and the first wire packing 6 after the first wire packing 6 passes through the corrugation 11 of the insulator 10, and the first wire packing 6 The test result supplied to the annular member arrangement | positioning part 62 is shown. In this test, after releasing the contact between the chuck mechanism 401 and the first wire packing 6, the first wire packing 6 was inserted into the annular member placement portion 62 by the weight of the insertion jig 402. In this test, a chuck mechanism 401 and an insertion jig 402 made of an austenitic stainless material, which is a nonmagnetic material, were used.

  Table 1 shows the result of evaluating whether or not 10,000 spark plugs 100 were produced and whether or not the first wire packing 6 was caught in 20 or more spark plugs 100 at that time. As shown in Table 1, according to this test, the contact between the chuck mechanism 401 and the first wire packing 6 was released before the first wire packing 6 passed the corrugation 11 of the insulator 10. In some cases, the first wire packing 6 was caught by 20 or more spark plugs 100. On the other hand, when the contact between the chuck mechanism 401 and the first wire packing 6 is released after the first wire packing 6 passes through the corrugation 11 of the insulator 10, the first wire packing 6 is caught. Was less than 20. Therefore, rather than releasing the contact between the chuck mechanism 401 and the first wire packing 6 before the first wire packing 6 passes through the corrugation 11 of the insulator 10, the first wire packing 6 It has been confirmed that the first wire packing 6 can be accurately placed on the annular member placement portion 62 by releasing the contact between the chuck mechanism 401 and the first wire packing 6 after passing through the corrugation 11.

  In addition, since the 2nd wire packing 7 is also arrange | positioned in the annular member arrangement | positioning part 62 by the method similar to the 1st wire packing 6, the 2nd wire packing 7 also passed the corrugation 11 of the insulator 10. The later release of the contact between the chuck mechanism 401 and the second wire packing 7 can be accurately arranged in the annular member arrangement portion 62.

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 annular member arrangement portion 62 without holding the terminal fitting 40 by the holding jig 403, and a state in which 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 annular member arrangement | positioning part 62 is shown. In this test, after the first wire packing 6 passes through the corrugation 11 of the insulator 10, the contact between the chuck mechanism 401 and the first wire packing 6 is released, and the first wire packing 6 is moved to the annular member arrangement portion. 62. After the contact between the chuck mechanism 401 and the first wire packing 6 was released, the first wire packing 6 was supplied to the annular member arrangement portion 62 by the weight of the insertion jig 402. In this test, a chuck mechanism 401 and an insertion jig 402 made of an austenitic stainless material, which is a nonmagnetic material, were used.

  Table 2 shows the results of evaluating whether or not 10,000 spark plugs 100 were produced, and whether or not the first wire packing 6 was caught during the production of 20 or more spark plugs 100. Yes. As shown in Table 2, according to this test, 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, When the terminal fitting 40 was pressed by the holding jig 403, the hooks of the first wire packing 6 were less than 20. Therefore, rather than not using the holding jig 403, the first wire packing 6 can be accurately arranged on the annular member arrangement portion 62 by holding the terminal fitting 40 in the axial direction OD using the holding jig 403. confirmed.

  In addition, since the 2nd wire packing 7 is also arrange | positioned in the annular member arrangement | positioning part 62 by the method similar to the 1st wire packing 6, also about the 2nd wire packing 7, by using the holding jig 403, It can arrange | position to the annular member arrangement | positioning part 62 exactly.

C-3. Evaluation test according to the material of the insertion jig:
Table 3 shows results of preparing insertion jigs 402 made of various materials and arranging the first wire packing 6 in the 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 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 each part of the wire packing supply device 400 including the insertion jig 402 is preferably formed of a non-magnetic material.

  As shown in the various test results shown above, according to the spark plug 100 manufacturing method of the present embodiment, the wire packings 6 and 7 can be accurately placed on the annular member placement portion 62 of the spark plug 100. It is.

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

  In the above embodiment, when filling the talc into the annular member arrangement part 62, solid talc called a talc ring is arranged in the annular member arrangement part 62 in the same manner as the wire packings 6 and 7. Also good. The talc ring is crushed into powder when the metal shell 50 is crimped.

  In the above embodiment, the wire packings 6 and 7 are supplied while holding the terminal fitting 40 using the holding jig 403. However, the wire packings 6 and 7 may be supplied without using the holding jig 403.

  In the above embodiment, the wire packings 6 and 7 are inserted into the annular member arrangement portion 62 by the weight of the insertion jig 402. On the other hand, a load may be applied to the insertion jig 402 to the extent that the wire packings 6 and 7 are not deformed, and the wire packings 6 and 7 may be pushed into the annular member placement portion 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 11 ... Corrugation 12 ... Shaft hole 13 ... Leg long part 15 ... 1st 2 stepped portion 17 ... front end side barrel portion 18 ... rear end side barrel portion 19 ... collar portion 20 ... center electrode 21 ... electrode base material 25 ... core material 30 ... ground electrode 40 ... terminal fitting 50 ... main fitting 51 ... tool clerk Joint portion 52 ... Mounting screw portion 53 ... Caulking portion 54 ... Seal portion 55 ... Seat surface 56 ... First step portion 58 ... Compression deformation portion 59 ... Screw neck 62 ... Annular member placement portion 65 ... Constriction 90 ... Electrode tip 100 DESCRIPTION OF SYMBOLS ... Spark plug 200 ... Engine head 201 ... Mounting screw hole 205 ... Opening peripheral part 400 ... Line packing supply apparatus 401 ... Chuck mechanism 402 ... Inserting jig 403 ... Holding jig 404 ... Depression 40 ... opening 408 ... recess 501 ... insertion hole O ... axis OD ... axial

Claims (7)

A central electrode extending in the axial direction;
A cylindrical insulator disposed on the outer periphery of the center electrode and having an uneven corrugation formed on the outer periphery on the rear end side;
A cylindrical metal shell disposed on the outer periphery of the insulator;
An annular member having a diameter larger than the maximum diameter of the insulator in the portion where the corrugation is formed;
An annular member disposition portion that is disposed on the front end side relative to the corrugation and is surrounded by an inner peripheral surface of a rear end portion of the metal shell and an outer peripheral surface of the insulator,
A spark plug manufacturing method comprising:
The annular member is allowed to pass through a portion where the corrugation is formed from the rear end side of the insulator while the annular member is in contact with a supply device for supplying the annular member to the annular member arrangement portion. The first step;
After the first step, the second step of releasing the contact between the supply device and the annular member and supplying the annular member to the annular member arrangement portion;
I have a,
In the second step, by releasing the contact between the supply device and the annular member, the annular member and the insertion jig disposed on the rear end side of the annular member are dropped, and the insertion jig A method for manufacturing a spark plug, characterized in that the annular member is supplied to the annular member arrangement portion by its own weight . It is a manufacturing method of the spark plug according to claim 1,
The supply device has a mechanism for chucking the annular member,
In the second step, after the first step, the contact between the supply device and the annular member is released by causing the supply device to release the chuck of the annular member. Method. It is a manufacturing method of the spark plug according to claim 1,
The supply device has a mechanism for adsorbing the annular member by sucking air;
In the second step, after the first step, the supply device stops suction of air, thereby releasing the contact between the supply device and the annular member. It is a manufacturing method of the spark plug according to claim 1,
The supply device has a mechanism for adsorbing the annular member by magnetic force,
In the second step, after the first step, the supply device releases the magnetic force to release the contact between the supply device and the annular member. It is a manufacturing method of the spark plug as described in any one of Claim 1- Claim 4 , Comprising:
The spark plug has a terminal fitting electrically connected to the center electrode at an end of the insulator,
In the second step, the annular member is supplied to the annular member placement portion in a state where the terminal fitting is pressed along the axial direction using a holding jig. A method for producing a spark plug according to any one of claims 1 to 5 ,
The annular member is made of a magnetic material,
The method of manufacturing a spark plug, wherein the supply device 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 5 ,
The method of manufacturing a spark plug, wherein the supply device is formed of an austenitic stainless material.

Images