JPH04371336A - Manufacture of metal parts comprising prinmarily spark plug - Google Patents

Abstract

PURPOSE:To provide the manufacture suitable for a mass production of metal parts comprising primarily spark plugs by the manufacture primarily of the heading of a well-formed product. CONSTITUTION:By heading a cylindrical material 1, forming an initial formed article 2, pressurizing the bottom face of a recessed part 22 on one end, and pushing out a head part and a connecting part 26 in the radial direction; a hexagonal pipe part 33, a leg part 35 with a small diameter, and a flange face 36 to connect both of them are formed; a hollow cylindrical head part 43 by forming the outer periphery on one end of the hexagonal pipe part into a cylinder with a small diameter, and a hexagonal body part 47 with a large diameter are formed; and also after a final heading article 6 is formed by punching through, by cutting, a neck part 11 with a small diameter between a head part 63 and the hexagonal body part 67, a thin calking part 12 at the end of the head part 63, and a thread part 13 on the outer periphery of the leg part are formed.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a spark plug main metal fitting having a cylindrical head and a hexagonal body having a diameter larger than the head.

0002

2. Description of the Related Art High-output engines that are used in severe situations such as automobile racing are provided with a cylindrical head and a large-diameter hexagonal body through a small-diameter neck, as shown in FIG. A spark plug P is used, which has a small-diameter leg extending from the body and a spark plug main metal fitting 100 in which a screw for attaching to the engine is formed on the outer periphery of the leg. This type of metal shell has conventionally been manufactured mainly by cutting, but in order to reduce manufacturing costs, it is desirable to simplify the cutting as much as possible and to manufacture by heading, which has excellent productivity.

0003

[Problems to be Solved by the Invention] When forming materials by heading, the pressing force necessary for the punch is required in order to improve productivity, extend the life of the die, and obtain a product with a high degree of shaping and strength. It is important that the amount of deformation of the material in the forging process is small, that the amount of deformation of the material during the forging process is not excessive, and that the deformation during molding is not unreasonable. An object of the present invention is to provide a method for manufacturing a spark plug main metal fitting that is suitable for mass production by a manufacturing method that mainly involves heading of a well-shaped product.

0004

[Means for Solving the Problems] The method for manufacturing a spark plug main metal fitting of the present invention involves forging a cylindrical material in a step-by-step manner in a plurality of forging stations constituted by punches and dies, and producing a final forged product. By cutting, one end side has a cylindrical head, the middle has a large diameter hexagonal body adjacent to the head via a small diameter neck, and the other end has a small diameter that is connected to the body through a flange surface. A method for manufacturing a cylindrical spark plug main metal fitting, which is a leg of a cylindrical spark plug, in which a cylindrical material is forged at a predetermined forging station, and one end is formed into a large-diameter metal fitting having a recess with a tapered portion on the end surface. An initial molded product with a head part, a small-diameter cylindrical leg part on the other end, and a connecting part between the two parts in the middle is forged, and at the next forging station,
By pressing the bottom of the recess on the one end side and pushing out the head and the connecting part in the radial direction of the shaft, a hexagonal part, a small diameter leg part, and a flange surface connecting the two are formed. At the forging station, the outer periphery of one end of the hexagonal part is formed into a cylinder with a small diameter to form a hollow cylindrical head and a hexagonal body having a larger diameter than the cylindrical head, and at the subsequent forging station, The bottom surface and the end surface of the other end of the recess are pressed to form a hollow part up to the middle of the leg, which is then penetrated by punching to form the final forged product.After that, the head and hexagonal body are cut by cutting. It is characterized by a small-diameter neck section, a thin caulked section at the end of the head, and a screw on the outer periphery of the leg.

[0005]

[Operations and Effects of the Invention] The method for manufacturing the spark plug main metal fitting of the present invention is to form a hexagonal cylindrical portion on one end side, and then extrude the outer periphery of the one end side of this hexagonal cylindrical portion so that the inner diameter is the same. Form the outer diameter into a cylinder with a small diameter while maintaining the
Since it has a cylindrical head and a hexagonal body with a larger diameter than the cylindrical head, the amount of displacement of the compressed material is small and the deformation is natural, making it possible to forge well-shaped products. It is suitable for mass production.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 schematically shows the construction of a multi-stage forging machine for carrying out the method of manufacturing a spark plug main metal fitting according to the present invention. The heading forming machine A has a die block D fixed at a predetermined position on the machine base, and a ram R that moves forward and backward toward the die block D (moves up and down in the figure). On the front surface of the die block D, a plurality of dies D1 to D8 are held by die holders and fixed in parallel. A plurality of punches P1 to P6 are respectively held by punch holders and fixed in parallel on the front surface of the ram R, facing the dies D1 to D8. Each of these opposing punches P
1 to P6 and dies D1 to D8 constitute a plurality of forging stations I to IV.

[0007] The metal shell 100 is subjected to a forging process in the following steps by the forging machine A described above. As shown in FIG. 1, a cylindrical material 1 that has been cut to a predetermined size and subjected to initial heading processing is sequentially headed at heading stations I to VI by a material transfer means (not shown), and sparks before cutting are sent to the final heading station VI. A heading product of the plug main metal fitting 100 is molded.

At heading station I, a cylindrical material is cut from steel, as shown in (■) in FIG.
Centering holes are formed at both ends using a punch P1 and a die D1, and a cylindrical shaping material 1 is pressed. At the heading station II, the cylindrical material 1 is processed by a punch P2 and a die D2 to form a large-diameter portion 23 having a recess 22 on one end side and a tapered surface 21 on the outer periphery, as shown in (■) in FIG.
An initial molded product 2 having a small diameter portion 25 having a recess 24 in the end face on the other end side and a connecting portion 26 in the middle is pressed.

[0009] At the heading station III, the initial molded product 2 is processed by a punch P3, a die D3, and a die D4.
Pressing the bottom surface of the recess 22 on the one end side, the connecting portion 2
6 on the annular plane flange surface 36, and
As shown, a hexagonal cylindrical portion 33 having a recess 32 with a circular diameter cross section reaching the flange surface 36, a cylindrical leg portion 35 with a small diameter,
and an intermediate molded product 3 having an intermediate flange surface 36 is forged.

At the forging station IV, the intermediate molded product 3 is reversed and inserted into the die D5, and the punch P is inserted into the die D5.
4 and die D5, the outer periphery of one end side portion of the hexagonal cylindrical portion 33 is extruded, and the outer periphery is formed into a cylinder with a small diameter. A hexagonal body portion 47 having a larger diameter than 43 is formed. As a result, it has a cylindrical recess 42 on one end side, as shown in (■) in FIG. An intermediate molded product 4 consisting of small-diameter cylindrical leg portions 45 connected together is forged.

At the forging station V, the intermediate molded product 4 is rotated back and supported by the dies D6 and D7, and the bottom surface of the recess 42 and the recess in the end surface of the leg portion 45 are punched with a small diameter punch P5. Press the bottom surface of 44. As a result, the recess 42 is deepened to the leg portion 45, forming a stepped recess 52, and having a deep recess 54 on the other end surface, the intermediate molded product 5 is forged as shown in (■) in FIG. . At the final station VI, supported by the die D8, the bottom surface of the recess 52 is pressed and penetrated by the punch P6, and the cylindrical head 6
3, a hexagonal body portion 67 having a larger diameter than the head portion, and a flange surface 6
6 and a leg portion 65 with a small diameter.

This final forged product 6 is provided with a small-diameter neck portion 11 on the outer periphery close to the body portion 67 by cutting, and the outer periphery of the rear end of the cylindrical head 63 is shaved to form a thin caulked portion 1.
2, and a screw 13 is further carved in the leg part 65, as shown in FIG.
A spark plug main metal fitting 100 shown in FIG. 1 is manufactured.

Next, another embodiment of the invention will be described. In the above-described heading station IV of FIG. 1, the intermediate molded product 3 is reversed, and the outer periphery of the one end side portion of the hexagonal cylinder portion 33 is shaped so that the inner diameter is the same as that of the cylindrical head 43 and the diameter is larger than the cylindrical head 43. However, this invention has a hexagonal body 47 as shown in FIG.
As shown in , by supporting the intermediate molded product 3 on the sleeves D10 and D11 and the die D9 without reversing it, and pressing the die D9 while holding the punch P7 in the recess 32,
The intermediate molded product 4 can be pressed in the same manner as described above. In this process, since there is no reverse action of the intermediate molded product 3, the molded product does not fly out, and there is an advantage that higher speed can be achieved.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view of a multi-stage forging machine used in the method of manufacturing a spark plug main metal fitting of the present invention.

FIG. 2 is a partial sectional view of a raw material, an intermediate molded product, and a final forged product in the forging process of the spark plug main metal fitting of the present invention.

FIG. 3 is a cross-sectional view of the spark plug.

FIG. 4 is a schematic cross-sectional view showing a method of manufacturing a spark plug main metal fitting according to another embodiment of the present invention.

[Explanation of symbols]

1 Material 2 Initial molded product 3 Intermediate molded product 4 Intermediate molded product 5 Intermediate molded product 6 Final heading product A Heading molding machine D Die block R Ram D1-D9 Die P1~P7 Punch D10, 11 Sleeve 100 Spark plug main metal fittings

Claims (1)

[Claims] Claim 1: A cylindrical material is forged in a step-by-step manner using a plurality of forging stations composed of punches and dies, and the final forged product is cut, so that one end has a cylindrical head and the middle has a diameter. Manufacture of a cylindrical spark plug main metal fitting, which has a large diameter hexagonal body adjacent to the head via a small neck, and a small diameter leg whose other end side is connected to the body via a flange surface. The method comprises: forging a cylindrical material at a predetermined forging station; one end having a large diameter head having a concavity having a tapered end; the other end having a small diameter cylindrical leg; The initial molded product with the intermediate portion as the connecting portion between the two is forged, and at the next forging station, the bottom of the recess on the one end side is pressed to push out the head and the connecting portion in the radial direction of the shaft, thereby forming a hexagonal shape. At the next forging station, the outer periphery of one end of the hexagonal part is formed into a cylinder with a small diameter to form a hollow cylindrical head and a flange surface connecting the two. A hexagonal body having a larger diameter than the cylindrical head is formed, and at a subsequent forging station, the bottom surface and the end surface of the other end of the recess are pressed to form the hollow part to the middle of the leg, and then by punching. The final forged product is formed by penetrating it, and then by cutting, a small diameter neck is formed between the head and the hexagonal body, a thin caulked part is formed at the end of the head, and a screw is formed on the outer periphery of the leg. A manufacturing method for the main metal fittings of spark plugs.