JP2020142325A - Cutting tip and processed component manufacturing method - Google Patents

Abstract

To stabilize a shape of a cut chip which generates when cutting a work-piece and manufacturing a processed component.SOLUTION: A cutting tip 53 comprises an intermediate projection 97 which is adjacent to both breaker wall parts 89, 95 between a first breaker wall part 89 and a second breaker wall part 95. The intermediate projection 97 extends to a second cutting edge 91 side with respect to an adjacent part of both breaker wall parts 89, 95, and projects in a height direction. Therefore, a cut chip generating from a seating face 37 can be flown backward on a side opposite to a first cutting edge 85 side along a wall of the intermediate projection 97. Further, the cutting tip 53 has such a shape that an upper end part 97a in the height direction on the first cutting edge 85 side of the intermediate projection 97 and an upper end part 89a of the first breaker wall part 89 exist on a same straight line, and extend in parallel to the first cutting edge 85. Consequently, a diameter of the cut chip, which generates from a region at a portion of an outer peripheral surface 35 which is connected to the seating face 37, can be easily stabilized.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to a cutting tip that can be used when manufacturing a main metal fitting of a spark plug, for example, and a method of manufacturing a member to be processed that can manufacture a member to be processed such as a main metal fitting of a spark plug.

Conventionally, the main metal fitting of a spark plug (that is, a spark plug) is manufactured by cutting out each part of the main metal fitting from a forged body formed by forging (see Patent Document 1).

Since the contour line of the main metal fitting has many undulations, when the main metal fitting is manufactured by cutting, a cutting tip having a cutting edge formed along the contour line of the main metal fitting is used.
As the cutting tip, for example, as shown in FIG. 9A, a cutting tip having a first cutting edge (P1) and a second cutting edge (P2) that bends and extends from the first cutting edge is known. As shown in FIG. 9B, when the root (P4) of the small diameter portion in the upper part of the forged body (P3) is cut by the first cutting edge of the cutting tip, the second cutting edge is simultaneously cut. Therefore, a plane (P5) adjacent to the root and substantially perpendicular to the small diameter portion can be machined.

Japanese Patent No. 5526161

However, the forged body is cut using the above-mentioned conventional cutting tip to form the root (that is, the neck) of the small diameter portion on the tip side of the main metal fitting and the surface (that is, the seat surface) that is substantially perpendicular to the neck. In some cases, the shape of the generated cutting chips was not stable, and in some cases, the cutting chips were wrapped around the main metal fittings.

This is because the width of the cutting chips generated from the portion corresponding to the neck portion and the width of the cutting chips generated from the portion corresponding to the seat surface are different, and the directions in which the cutting chips flow can intersect. ..

The present disclosure has been made in view of these problems. For example, a cutting tip capable of stabilizing the shape of cutting chips generated when a member to be machined such as a main metal fitting is manufactured by cutting, and a member to be machined. It is an object of the present invention to provide the manufacturing method of.

(1) One aspect of the present disclosure relates to a cutting tip for manufacturing a workpiece having a first surface and a second surface substantially perpendicular to the first surface by cutting the material to be cut. It is a thing.
This cutting tip has a portion corresponding to the first surface of the member to be machined in the material to be machined, a first cutting portion for cutting, and a portion of the material to be machined corresponding to the second surface of the member to be machined. It is provided with a second cutting portion for cutting.

Further, this cutting tip has the following configuration in a plan view seen from the rake face direction.
The first cutting portion is a first cutting edge for cutting in contact with a portion corresponding to the first surface, and is a first cutting edge extending linearly and a first cutting edge side from the first cutting edge. A first rake surface extending rearward on the opposite side and a first breaker wall portion protruding rearward from the first rake surface at a predetermined height on the rear side of the first rake surface are provided.

The second cutting portion is a second cutting edge for cutting by contacting a portion corresponding to the second surface, and is connected to the end portion of the first cutting edge and is bent at the connecting portion to perform the first cutting. A second cutting edge extending to the side opposite to the blade side, a second rake surface extending from the second cutting edge to the rear opposite to the second cutting edge side, and a second rake surface on the rear side of the second rake surface. It is provided with a second breaker wall portion that protrudes from the surface at a predetermined height.

Further, the upper end portion in the height direction of the first breaker wall portion on the first cutting edge side has a shape extending in parallel with the first cutting edge.
Moreover, it is an intermediate protrusion between the first breaker wall portion and the second breaker wall portion and adjacent to the first breaker wall portion and the second breaker wall portion, and is the first breaker wall portion and the second breaker wall portion. It extends toward the second cutting edge side from the adjacent portion of the wall portion, and has an intermediate protruding portion that protrudes in the height direction.

The upper end portion of the intermediate protrusion on the first cutting edge side in the height direction and the upper end portion of the first breaker wall portion are on the same straight line and have a shape extending in parallel with the first cutting edge. ..
As described above, the cutting tip of one aspect of the present disclosure has an intermediate protrusion between the first breaker wall portion and the second breaker wall portion, which is adjacent to the first breaker wall portion and the second breaker wall portion. I have. Specifically, it is provided with an intermediate projecting portion that extends toward the second cutting edge side from the adjacent portions of the first breaker wall portion and the second breaker wall portion and protrudes in the height direction.

Therefore, due to the presence of this intermediate protrusion, when cutting a material to be machined (for example, a forged body) to be a member to be machined, cutting chips generated from the second surface are made to follow the wall of the intermediate protrusion. Therefore, it can be flowed to the rear on the side opposite to the first cutting edge side. That is, due to the presence of the intermediate protrusion, the cutting chips generated from the second surface flow backward along between the intermediate protrusion and the second surface, so that the cutting chips generated by the first cutting edge and the second surface The cutting chips generated by the cutting edge can be easily separated. As a result, there is an effect that the shape of the cutting chips generated from the first surface and the second surface is stabilized. Normally, the width of the cutting chips generated by the second cutting edge is narrower than that of the cutting chips generated by the first cutting edge.

Moreover, in this cutting tip, the upper end portion in the height direction of the intermediate protrusion on the first cutting edge side and the upper end portion of the first breaker wall portion are on the same straight line and parallel to the first cutting edge. It has an elongated shape.

Therefore, the diameter of the cutting chips generated from the first surface can be easily and stably generated, and the diameter of the cutting chips generated from the region of the first surface that is in contact with the second surface can also be easily stabilized.

As described above, since the cutting tip of one aspect of the present disclosure is provided with the intermediate protrusion as described above, when the first surface and the second surface of the member to be machined are formed by cutting, the cutting tip may be formed. It has a remarkable effect of stabilizing the shape of the cutting chips generated. Therefore, the diameter of the cutting chips becomes large, and it is possible to prevent the cutting chips from being wound around the main metal fitting, for example.

In addition, here, substantially vertical means that it is substantially vertical, and for example, a range of 90 degrees to 95 degrees can be adopted (the same applies hereinafter).
(2) In one aspect of the present disclosure, the first cutting edge and the upper end portion of the first breaker wall portion on the first cutting edge side in the height direction are the first in a plan view of the cutting tip viewed from the rake face direction. The height of the distance W1 and the second distance W2, which is the shortest distance between the second cutting edge and the upper end of the intermediate protrusion in the height direction, and the height of the second cutting edge and the second breaker wall on the second cutting edge side. The third distance W3 with the upper end portion in the direction may have a relationship of W2 <W1 and W2 <W3.

In this way, by "having a relationship of W2 <W1 and W2 <W3", a portion having a particularly small breaker width can be provided in a portion of the second cutting portion adjacent to the first cutting portion. By having a portion having a particularly small breaker width (that is, a portion where the distance from the cutting edge to the breaker wall is small), the cutting chips generated from the outer peripheral surface 35a and the cutting chips generated from the second surface can be more easily separated. be able to. Further, since the cutting chips generated from the second surface can be aligned with the wall of the intermediate protrusion, it is possible to generate cutting chips having a more stable shape.

Further, since the breaker width on the second cutting edge side can be sufficiently secured by "having the relationship of W2 <W3", there is an advantage that the cutting chips generated from the second cutting portion do not easily damage the second surface.

(3) In one aspect of the present disclosure, the first distance W1 and the third distance W3 may have a relationship of W1> W3.
The cutting resistance in the second cutting portion is smaller than the cutting resistance in the first cutting portion, and the cutting chips generated from the second cutting portion are usually smaller than the cutting chips generated from the first cutting portion. Therefore, by configuring so as to have a “W1> W3 relationship”, there is an advantage that the diameters of the cutting chips generated from the first cutting portion and the cutting chips generated from the second cutting portion are stable.

(4) In one aspect of the present disclosure, the cutting tip may be used for cutting the surface of a main metal fitting used for manufacturing a spark plug.
(5) Another aspect of the present disclosure is a method for manufacturing a member to be machined, which comprises manufacturing the member to be machined using the cutting tip described above.

In this method of manufacturing a member to be machined, the member to be machined has a cylindrical or cylindrical neck portion, and has a first surface which is an outer peripheral surface of the neck portion and a first surface which projects substantially perpendicularly outward from the first surface in the radial direction. It has two sides.

Then, in this method of manufacturing the member to be machined, the material to be machined is rotated about its own axis. At the same time, by moving the cutting tip arranged so that the first cutting edge faces the portion corresponding to the first surface toward the portion corresponding to the neck portion, the portion corresponding to the first surface is first cut. Along with cutting with a blade, the part corresponding to the second surface is cut with a second cutting edge.

In this way, by using the cutting tip described above, the processed portion of the material to be cut, that is, the first surface (for example, the outer peripheral surface of the neck portion) and the second surface (for example, the seat surface) of the member to be processed (for example, the main metal fitting) When cutting the part corresponding to, the shape of the generated cutting chips is stable. Therefore, the diameter of the cutting chips becomes large, and it is possible to prevent the cutting chips from being wound around the main metal fitting, for example.

Therefore, there is an effect that work efficiency at the time of manufacturing a member to be processed such as a main metal fitting is improved.
(6) In another aspect of the present disclosure, the member to be processed may be a main metal fitting used for manufacturing a spark plug.

It is a partial sectional view which shows the spark plug of an embodiment. It is a process drawing which shows the manufacturing method of a spark plug. It is a process drawing which shows the manufacturing method of the main metal fitting. It is a side view which shows the shape of the forged body (material to be cut). It is explanatory drawing which shows the state which manufactures the main metal fitting by a cutting tool. It is a top view which shows the shape of a cutting tip. 7A is an enlarged plan view of a part of the cutting tip, FIG. 7B is a sectional view showing a section II of FIG. 7A, FIG. 7C is a sectional view showing a section II-II of FIG. 7A, and FIG. 7D is a sectional view of FIG. It is sectional drawing which shows the III-III cross section. It is explanatory drawing which shows the state which manufactures the main metal fitting by a cutting tip. It is explanatory drawing of the prior art.

Hereinafter, embodiments of a method for manufacturing a cutting chip and a member to be processed to which the present disclosure has been applied will be described with reference to the drawings.
[1. Embodiment]
[1-1. Spark plug]
First, a spark plug (that is, a spark plug) in which a main metal fitting which is a member to be processed is used will be described with reference to FIG.

As shown in FIG. 1, the spark plug 1 is a long member extending along the axis O, which is the axis. In the following description, the lower part of FIG. 1 is referred to as the "tip side" of the spark plug 1, and the upper part of FIG. 1 is referred to as the "rear end side" of the spark plug 1.

The spark plug 1 includes a center electrode 3, an insulating insulator 5, a main metal fitting 7, and a ground electrode 9. The axis O of the spark plug 1 is also the axis of each member of the center electrode 3, the insulating insulator 5, and the main metal fitting 7.

The center electrode 3 of the spark plug 1 is a rod-shaped electrode. The center electrode 3 is made of a nickel alloy containing nickel as a main component, including Inconel (registered trademark). The outer surface of the center electrode 3 is electrically insulated from the outside by an insulating insulator 5. The center electrode 3 may have a core portion having excellent thermal conductivity inside. For example, the core is mainly made of copper.

The tip end side of the center electrode 3 projects from the tip end side of the insulating insulator 5. The rear end side of the center electrode 3 is electrically connected to the rear end side of the insulating insulator 5. The rear end side of the center electrode 3 is electrically connected to the rear end side of the insulating insulator 5 via the seal body 11, the ceramic resistor 13, the seal body 15, and the terminal fitting 17.

The insulating insulator 5 is a tubular insulator. The insulating insulator 5 is made by firing an insulating ceramic material such as alumina. The insulating insulator 5 includes a shaft hole 19 which is a through hole along the axis O. The shaft hole 19 houses the center electrode 3, the seal body 11, the ceramic resistor 13, the seal body 15, and the terminal fitting 17.

The main metal fitting 7 is a tubular metal body. The main metal fitting 7 is a metal body made of nickel-plated low carbon steel. The main metal fitting 7 may be a metal body made of galvanized low carbon steel or a metal body made of an unplated (non-plated) nickel alloy.

The main metal fitting 7 is caulked and fixed to the outer surface of the insulating insulator 5 in a state of being electrically insulated from the center electrode 3. The main metal fitting 7 is formed with a front end surface 21, a tip portion 23, a body portion 25, a groove portion 27, a tool engaging portion 29, and a caulking portion 31 in this order from the front end side to the rear end side.

The tip surface 21 of the main metal fitting 7 is formed on the tip side of the main metal fitting 7. The tip surface 21 is a hollow circular surface, and a ground electrode 9 is joined to the tip surface 21. The insulating insulator 5 and the center electrode 3 project from the center of the tip surface 21.

The body portion 25 is a collar-shaped portion protruding in the outer peripheral direction from the groove portion 27. The body portion 25 compresses a gasket 33 arranged between the body portion 25 and the internal combustion engine 30.
The tip portion 23 is a tubular portion having a diameter smaller than that of the body portion 25 and projecting toward the tip end side of the body portion 25. A mounting screw portion 24 having a thread is provided on the outer peripheral surface of the tip portion 23. In the present embodiment, the spark plug 1 can be attached to the internal combustion engine 30 by screwing the mounting screw portion 24 of the main metal fitting 7 into the screw hole 30a of the internal combustion engine 30.

Further, the base of the tip portion 23 is a cylindrical neck portion 35 having no thread formed. The gasket 33 is fitted on the neck portion 35. Further, a seat surface (second surface) 37 on which the gasket 33 is seated is formed at the tip of the body portion 25. The angle θ1 (see FIG. 5) formed by the outer peripheral surface (first surface) 35a of the neck portion 35 and the seat surface 37 connected to the outer peripheral surface 35a is substantially vertical (for example, in the range of 90 degrees to 95 degrees). ing.

The groove portion 27 is formed between the body portion 25 and the tool engaging portion 29. The groove portion 27 is a portion that bulges in the outer peripheral direction when the main metal fitting 7 is caulked and fixed to the insulating insulator 5.
The tool engaging portion 29 is a collar-shaped portion protruding in the outer peripheral direction from the groove portion 27. The tool engaging portion 29 has a shape that engages a tool (not shown) for attaching the ignition plug 1 to the internal combustion engine 30.

The caulking portion 31 is a portion that has been plastically processed so as to be in close contact with the insulating insulator 5 when the main metal fitting 7 is caulked and fixed to the insulating insulator 5. In the present embodiment, powdered talc (talc) is sealed in the region between the crimped portion 31 of the main metal fitting 7 and the insulating insulator 5.

[1-2. How to manufacture spark plugs]
Next, the outline of the manufacturing method of the spark plug 1 will be described.
As shown in FIG. 2, when manufacturing the spark plug 1, a step of manufacturing the center electrode 3 (step S100), a step of manufacturing the insulating insulator 5 (step S110), and a step of manufacturing the main metal fitting 7 (step). By performing S120) respectively, the center electrode 3, the insulating insulator 5, and the main metal fitting 7 are prepared respectively. The details of the method for manufacturing the main metal fitting 7 will be described later.

Then, after preparing the center electrode 3, the insulating insulator 5, and the main metal fitting 7, the spark plug 1 is completed through a step (step S130) of assembling these parts to manufacture the spark plug 1.

Specifically, in the step of assembling the parts of the spark plug 1 (step S130), the center electrode 3 is inserted into the insulating insulator 5, and the insulating insulator 5 is further inserted into the main metal fitting 7. After that, the main metal fitting 7 is caulked and fixed to the insulating insulator 5, and the ground electrode 9 joined to the main metal fitting 7 is bent to complete the spark plug 1.

[1-3. Main metal fitting manufacturing method]
Next, a method of manufacturing the main metal fitting 7 will be described.
As shown in FIG. 3, when manufacturing the main metal fitting 7, first, forging processing (step S200) is performed. Specifically, using a cold forging machine, a columnar low-carbon steel material (for example, JIS standard S10C, S15C, etc.) which is the material of the main metal fitting 7 is pressed in a plurality of times, and the main metal fitting 7 is pressed. A forged body (that is, a material to be cut) 41 (see FIG. 4) molded into the original shape is created.

The outer shape of the forged body 41 is the outer diameter G1 of the tip portion 41c corresponding to the tip end side (that is, the tip portion 23) of the main metal fitting 7, and the outer diameter G2 of the rear end portion 41b on the opposite side of the tip portion 41a. The outer diameter G3 of the intermediate portion 41c between the front end portion 41a and the rear end portion 41b is a different cylinder. In addition, G3> G2> G1.

After the forging process, a cutting process (step S210) is performed. Specifically, the shape of each part of the main metal fitting 7 (that is, the member to be machined) is carved out by cutting the outer circumference and the inner circumference of the forged body 41 created by the forging process with a lathe (not shown). The details of this cutting process will be described later.

After the cutting process, the ground electrode 9 is welded to the main metal fitting 7 (step S220). In the present embodiment, unlike the finished product, the ground electrode 9 for welding to the main metal fitting 7 is a straight wire rod.

After welding the ground electrode 9 to the main metal fitting 7, thread cutting is performed (step S230) to form a screw thread on the tip portion 23 of the main metal fitting 7. After that, the main metal fitting 7 is completed by plating the main metal fitting 7 (step S240).

[1-4. Cutting tools]
Next, the overall configuration of the cutting tool used when performing the above-mentioned cutting process will be described.
As shown in FIG. 5, when the main metal fitting 7 is manufactured by cutting, a cutting tool (that is, a cutting tool) 43 for cutting the forged body 41 is used. Note that FIG. 5 shows a state immediately after cutting.

The cutting tool 43 includes three holdings (ie, shanks) 45, 47, 49 and four cutting tips 51, 53, 55, 57. The number of holding portions 45 to 49 and cutting tips 51 to 57 is not particularly limited.

Each of the cutting tips 51 to 57 is provided with holding holes 61, 63, 65, 67 that penetrate the cutting tips 51 to 57 in the thickness direction at substantially the center, and the holding holes 61, 63, 65, 67 are provided. It is fixed to each holding portion 45 to 49 by screwing each fixing screw (not shown). The cutting tip 51 is fixed to the holding portion 45, the cutting tip 53 is fixed to the holding portion 47, and the cutting tips 55 and 57 are fixed to the holding portion 49.

In this cutting process, the member serving as the main metal fitting 7 (specifically, the forged body 41 before the cutting process) is fixed so that the axis O of the forged body 41 coincides with the rotation axis of the lathe. Then, while rotating the forged body 41 by rotating the rotation axis of the lathe, the shape of each part of the main metal fitting 7 is carved out by pressing the cutting tool 43 against the forged body 41 from the direction orthogonal to the rotation axis.

Specifically, the cutting tip 51 cuts out the shape of the end portion of the main metal fitting 7 on the tip end side (upper side of FIG. 5).
The cutting tip 53 cuts out the shapes of the outer peripheral surface (first surface) 35a and the seat surface (second surface) 37 of the neck portion 35 of the main metal fitting 7.

The cutting tip 55 cuts out the shapes of the front end side and the rear end side of the body portion 25.
The cutting tip 57 cuts out the shape of the end portion on the rear end side (lower side of FIG. 5) of the main metal fitting 7.

[1-5. Cutting tip]
Next, among the cutting tips 51 to 57, the cutting tip 53 that cuts the portion of the forged body 41 that becomes the neck portion 35 and the seat surface 37 will be described.

As shown in FIGS. 6 and 7, the cutting tip 53 has a plate shape and has a substantially polygonal shape in a plan view when viewed from the thickness direction. Here, the plan view is a Cartesian coordinate system of XYZ, and is viewed from the Z-axis direction perpendicular to the XY plane (direction perpendicular to the paper surface). In other words, it is viewed from the side on which the first rake face 87 and the second rake face 93, which will be described later, are formed (that is, a plan view seen on the rake face side).

The cutting tip 53 includes a pair of cutting portions 80L and 80R in the left-right direction of FIG. 6 as a portion for cutting the forged body 41. Since the pair of cutting portions 80L and 80R have the same configuration provided point-symmetrically with the holding hole 63 interposed therebetween, one of them (the cutting portion 80L on the left side of FIG. 6) is taken as an example below. explain.

The cutting portion 80L cuts the forged body 41 to form a first cutting portion 81 that forms an outer peripheral surface (first surface) 35a of the neck portion 35 of the main metal fitting 7, and a seat surface (second surface) 37. A second cutting portion 83 is provided.

Further, the cutting tip 53 has the following configuration in a plan view seen from the rake face direction (that is, the Z-axis direction).
The first cutting portion 81 is a first cutting edge 85 for cutting in contact with a portion (that is, a part of the forged body 41) corresponding to the outer peripheral surface 35a of the main metal fitting 7 in the forged body 41, and is linear. It is provided with a first cutting edge 85 extending to. Here, the first cutting edge 85 is a straight line in a plan view.

Further, the first cutting portion 81 has a first rake face 87 extending from the first cutting edge 85 to the rear side (right side in FIG. 6) opposite to the first cutting edge 85 side, and the rear side of the first rake face 87. A first breaker wall portion 89 projecting from the first rake face 87 to the front side (see FIG. 6) in the Z-axis direction at a predetermined height is provided.

As shown in FIG. 7B, the first breaker wall portion 89 rises upward (specifically, diagonally backward) from the first rake face 87 in the Z-axis direction. The height of the first breaker wall portion 89 (that is, the height from the lowest portion of the first rake face 87) is, for example, 0.84 mm in the range of 0.77 to 0.92 mm.

The second cutting portion 83 includes a second cutting edge 91 for cutting in contact with a portion (that is, a part of the forged body 41) corresponding to the seat surface 37 of the main metal fitting 7 in the forged body 41. That is, the second cutting edge 85 is connected to the end portion (lower end portion in FIG. 6) and is bent at the connecting portion and extends to the side opposite to the first cutting edge 85 side (right side in FIG. 6). It has a cutting edge 91. In a plan view, the angle θ2 formed by the first cutting edge 85 and the second cutting edge 91 is substantially vertical (for example, 90 degrees to 95 degrees).

Further, the second cutting portion 83 has a second rake face 93 extending from the second cutting edge 91 to the rear side (upper side of FIG. 6) opposite to the second cutting edge 91 side, and the rear side of the second rake face 93. On the side, a second breaker wall portion 95 that protrudes toward the front side in the Z-axis direction at a predetermined height from the second rake face 93 is provided.

As shown in FIG. 7D, the second breaker wall portion 95 rises upward (specifically, diagonally backward) from the second rake face 93 in the Z-axis direction. The height of the second breaker wall portion 95 (that is, the height from the lowest portion of the second rake face 93) is, for example, 0.75 mm in the range of 0.68 to 0.83 mm.

Further, the upper end portion 89a in the height direction of the first breaker wall portion 89 on the first cutting edge 85 side has a shape extending in parallel with the first cutting edge 85 in the Y-axis direction. Here, the upper end portion 89a of the first breaker wall portion 89 is a straight line in a plan view.

Further, between the first breaker wall portion 89 and the second breaker wall portion 95, an intermediate protrusion 97 adjacent to the first breaker wall portion 89 and the second breaker wall portion 95 is provided. The intermediate protruding portion 97 extends toward the second cutting edge 91 side from the adjacent portions of the first breaker wall portion 89 and the second breaker wall portion 95, and protrudes in the height direction.

That is, the width (that is, the dimension in the X direction) of the intermediate protrusion 97 becomes narrower from between the first breaker wall portion 89 and the second breaker wall portion 95 toward the lower part of FIG. Protruding like. The height of the intermediate protrusion 97 is the same as the height of the first breaker wall portion 89 and the second breaker wall portion 95.

Specifically, on the right side of FIG. 7A from the intermediate protrusion 97, the distance between the second breaker wall portion 95 and the second cutting edge 91 (that is, the width: depth of the second rake face 93) is almost constant, and the second breaker The wall portion 95 is smoothly curved, but at the connection portion of the second breaker wall portion 95 with the intermediate protrusion 97 at the left end, the intermediate protrusion 97 has a steep angle toward the lower left of FIG. 7A (for example, the same). It is bent in a straight line at an angle of about 45 degrees with respect to the vertical direction in the figure. The right side (bent portion, etc.) of the intermediate portion protruding portion 97 in the figure is a straight line.

Moreover, the upper end portion 97a in the height direction of the intermediate protrusion 97 on the first cutting edge 85 side and the upper end portion 89a of the first breaker wall portion 89 are on the same straight line and parallel to the first cutting edge 85. Extends along the Y-axis direction.

Although the first breaker wall portion 89 and the intermediate protrusion portion 97 are continuous, the first breaker wall portion 89 and the intermediate protrusion portion 97 are connected portions between the second breaker wall portion 95 and the intermediate protrusion portion 97. Can be classified at the same position as (the same position in the vertical direction of FIG. 7A). That is, the first breaker wall portion 89 and the intermediate protrusion portion 97 can be separated by a normal line passing through the connecting portion among the normal lines for the first cutting edge 85 (that is, the same straight line).

Further, the second breaker wall portion 95 and the intermediate protrusion portion 97 can be separated from each other at a portion where the intermediate protrusion portion 97 is bent and the width of the second rake face 93 is narrowed. That is, since the right side portion of FIG. 7A of the intermediate protrusion 97 is bent from the second breaker wall portion 95, the second breaker wall portion 95 and the intermediate protrusion 97 can be separated by the bent portion. it can. The bent portion (that is, the connecting portion) is located at the upper end of the second rake face 93 in FIG. 7A.

Further, in the present embodiment, in the plan view, the first distance W1 between the first cutting edge 85 and the upper end portion 89a in the height direction on the first cutting edge 85 side of the first breaker wall portion 89a and the second The second distance W2, which is the shortest distance between the cutting edge 91 and the upper end portion 97a in the height direction of the intermediate protruding portion 97, and the height of the second cutting edge 91 and the second breaker wall portion 95 on the second cutting edge 91 side. The third distance W3 with the upper end portion 95a in the direction has a relationship of W2 <W1 and W2 <W3.

The third distance W3 is the distance between the second cutting edge 91 and the upper end portion 95a of the second breaker wall portion 95, but when the third distance W3 differs depending on the position, the average of the maximum distances is adopted. To do. Further, the third distance W3 is a distance in the normal direction perpendicular to the tangent line of the second cutting edge 91 in a plan view.

Further, the first distance W1 and the third distance W3 have a relationship of W1> W3.
Here, as the first distance W1, for example, 1.5 mm in the range of 1.4 to 1.6 mm can be adopted. As the second distance W2, for example, 0.5 mm in the range of 0.4 to 0.6 mm can be adopted. As the third distance W3, for example, 1.0 mm in the range of 0.9 to 1.1 mm can be adopted.

Then, when the main metal fitting 7 is manufactured by cutting the forged body 41 as described above using the cutting tip 53 having such a configuration, (the main metal fitting 7 is formed) as shown in FIG. ) Attach the forged body 41 to the lathe, rotate the forged body 41 around its own axis O, and move the cutting tool 43 toward the portion corresponding to the neck 35 (of the main metal fitting 7) of the forged body 41. ..

Specifically, the cutting tip 53 in which the first cutting edge 85 is arranged so as to face the portion corresponding to the outer peripheral surface 35a of the neck portion 35 is moved toward the portion of the forged body 41 that forms the neck portion 35. As a result, the portion corresponding to the outer peripheral surface 35a is cut by the first cutting edge 85 to form the outer peripheral surface 35a, and the portion corresponding to the seat surface 37 is cut by the second cutting edge 91 to form the seat. The surface 37 is formed.

[1-6. effect]
According to the present embodiment described in detail above, the following effects can be obtained.
(1a) The cutting tip 53 of the present embodiment has an intermediate protrusion between the first breaker wall portion 89 and the second breaker wall portion 95 adjacent to the first breaker wall portion 89 and the second breaker wall portion 95. The portion 97 includes an intermediate protruding portion 97 that extends toward the second cutting edge 91 side from the adjacent portions of the first breaker wall portion 89 and the second breaker wall portion 95 and protrudes in the height direction.

Therefore, when the forged body 41 to be the main metal fitting 7 is cut by the intermediate protrusion 97, the cutting chips generated from the seat surface 37 are made to follow the wall of the intermediate protrusion 97 so that the first cutting edge is cut. It can flow to the rear on the opposite side to the 85 side. That is, due to the presence of the intermediate protrusion 97, the cutting chips generated from the seat surface 37 flow backward along between the intermediate protrusion 97 and the seat surface 37, so that the cutting chips generated by the first cutting edge 85 and the cutting chips are generated. , The cutting chips generated by the second cutting edge 91 can be easily separated. As a result, there is an effect that the shape of the cutting chips generated from the outer peripheral surface 35a and the seat surface 37 is stabilized.

Further, in the cutting tip 53, the upper end portion 97a in the height direction of the intermediate protruding portion 97 on the first cutting edge 85 side and the upper end portion 89a of the first breaker wall portion 89 are on the same straight line, and the first 1 It has a shape extending parallel to the cutting edge 85. Therefore, the diameter of the cutting chips generated from the outer peripheral surface 35a can be easily and stably generated, and the diameter of the cutting chips generated from the region of the outer peripheral surface 35a in contact with the seat surface 37 can be easily and stably generated.

On the other hand, if the upper end portion 97a in the height direction of the intermediate protrusion 97 on the first cutting edge 85 side and the upper end portion 89a of the first breaker wall portion 89 are not on the same straight line, the following points are I am concerned.

When the upper end portion 97a in the height direction of the intermediate protruding portion 97 on the first cutting edge 85 side extends toward the first cutting edge 85 side, the cutting resistance in the region of the outer peripheral surface 35a that is in contact with the seat surface 37. And the diameter of the cutting chips generated from the area may not be stable. Further, when the upper end portion 97a in the height direction of the intermediate protruding portion 97 on the first cutting edge 85 side extends rearward on the side opposite to the first cutting edge 85, the cutting chips generated from the seat surface 37 are intermediately projected. It may be difficult to flow the first cutting edge to the rear side opposite to the 85 side so as to follow the wall of the portion 97.

As described above, the cutting tip 53 of the present embodiment is used to generate cutting chips when cutting a portion of the forged body 41 corresponding to the outer peripheral surface 35a and the seat surface 37 of the neck portion 35 of the main metal fitting 7. It has a remarkable effect of stabilizing the shape. Therefore, the diameter of the cutting chips becomes large, and it is possible to prevent the cutting chips from being wrapped around the body fitting 7.

Therefore, there is an effect that the work efficiency when manufacturing the main metal fitting 7 is improved.
(1b) In the present embodiment, the first distance W1, the second distance W2, and the third distance W3 have a relationship of W2 <W1 and W2 <W3, so that the second cutting portion 83 A portion having a particularly small breaker width can be provided in a portion adjacent to the first cutting portion 81.

Since there is a portion having a particularly small breaker width, the cutting chips generated from the outer peripheral surface 25a and the cutting chips generated from the bearing surface 37 can be more easily separated. Further, since the cutting chips generated from the seat surface 37 can be aligned with the wall of the intermediate protrusion 97, it is possible to generate cutting chips having a more stable shape.

Further, since the breaker width on the second breaker wall portion 95 side can be sufficiently secured by having the relationship of W2 <W3, there is an advantage that the cutting chips generated from the second cutting portion 83 do not easily damage the seat surface 37. ..

(1c) In the present embodiment, the first distance W1 and the third distance W3 have a relationship of W1> W3. As a result, the diameters of the cutting chips generated from the first cutting portion 81 and the cutting chips generated from the second cutting portion 83 (that is, the cutting chips narrower than the cutting chips generated from the first cutting portion 81) are stabilized. There are advantages.

[1-7. Correspondence of wording]
Here, the correspondence between words will be described.
Main metal fitting 7, outer peripheral surface 35a, seat surface 37, forged body 41, cutting tip 53, first cutting portion 81, second cutting portion 83, first cutting edge 85, first rake surface 87, first 1 The breaker wall portion 89, the second cutting edge 91, the second rake surface 93, the second breaker wall portion 95, and the intermediate projecting portion 97 are the members to be machined, the first surface, the second surface, and the machine to be cut, respectively. Material, cutting tip, 1st cutting part, 2nd cutting part, 1st cutting edge, 1st rake surface, 1st breaker wall part, 2nd cutting edge, 2nd rake surface, 2nd breaker wall part, intermediate protrusion Corresponds to one example.

[2. Other embodiments]
Although the embodiments of the present disclosure have been described above, it goes without saying that the present disclosure is not limited to the above-described embodiments, and various forms can be adopted.

(2a) For example, within the scope of the present disclosure, the shape of the cutting tip can be appropriately changed.
(2b) Further, the material to be cut does not have to be a forged body. That is, a material having a shape that does not require forging may be prepared and used as the material to be cut.

(2c) The functions of one component in the above embodiment may be dispersed as a plurality of components, or the functions of the plurality of components may be integrated into one component. Further, a part of the configuration of the above embodiment may be omitted. Further, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other embodiment. It should be noted that all aspects included in the technical idea specified from the wording described in the claims are embodiments of the present disclosure.

1 ... Spark plug 7 ... Main metal fitting 35 ... Neck 35a ... Outer surface (first surface)
37 ... Seat surface (second surface)
41 ... Forged body 53 ... Cutting tip 81 ... 1st cutting part 83 ... 2nd cutting part 85 ... 1st cutting edge 87 ... 1st rake face 89 ... 1st breaker wall part 91 ... 2nd cutting edge 93 ... 2nd rake Surface 95 ... Second breaker wall 97 ... Intermediate protrusion

Claims (6)

A cutting tip for manufacturing a member to be machined having a first surface and a second surface substantially perpendicular to the first surface by cutting the material to be machined.
A first cutting portion for cutting a portion of the material to be machined corresponding to the first surface of the member to be machined.
A second cutting portion for cutting a portion of the material to be machined corresponding to the second surface of the member to be machined.
Is equipped with
In a plan view of the cutting tip from the rake face direction,
The first cutting portion is
A first cutting edge for cutting in contact with a portion corresponding to the first surface, the first cutting edge extending linearly, and
A first rake face extending rearward from the first cutting edge on the side opposite to the first cutting edge side,
On the rear side of the first rake surface, a first breaker wall portion protruding from the first rake surface at a predetermined height, and
With
The second cutting portion is
A second cutting edge for cutting in contact with a portion corresponding to the second surface, which is connected to the end of the first cutting edge and is bent at the connecting portion to the side of the first cutting edge. With the second cutting edge extending to the opposite side,
A second rake face extending rearward from the second cutting edge on the side opposite to the second cutting edge side,
On the rear side of the second rake surface, a second breaker wall portion protruding from the second rake surface at a predetermined height, and
With
The upper end portion of the first breaker wall portion on the first cutting edge side in the height direction has a shape extending in parallel with the first cutting edge.
An intermediate protrusion between the first breaker wall portion and the second breaker wall portion, which is adjacent to the first breaker wall portion and the second breaker wall portion, and is the first breaker wall portion and the first breaker wall portion. It is provided with an intermediate protruding portion that extends toward the second cutting edge side from the adjacent portion of the second breaker wall portion and protrudes in the height direction.
The upper end portion of the intermediate protrusion on the first cutting edge side in the height direction and the upper end portion of the first breaker wall portion are on the same straight line and extend in parallel with the first cutting edge. Has a shape that
Cutting tip. In a plan view of the cutting tip from the rake face direction,
The first distance W1 between the first cutting edge and the upper end portion in the height direction on the first cutting edge side of the first breaker wall portion, and the height of the second cutting edge and the intermediate protruding portion. The second distance W2, which is the shortest distance from the upper end portion in the direction, and the third distance W3 between the second cutting edge and the upper end portion in the height direction on the second cutting edge side of the second breaker wall portion. Has a relationship of W2 <W1 and W2 <W3.
The cutting tip according to claim 1. The first distance W1 and the third distance W3 have a relationship of W1> W3.
The cutting tip according to claim 2. The cutting tip is for cutting the surface of a main metal fitting used for manufacturing an ignition plug.
The cutting tip according to any one of claims 1 to 3. A method for manufacturing a member to be machined, wherein the member to be machined is manufactured by using the cutting tip according to any one of claims 1 to 3.
The member to be processed has a cylindrical or columnar neck portion, and has a first surface which is an outer peripheral surface of the neck portion and a second surface which projects substantially perpendicularly outward in the radial direction from the first surface. Is equipped with
The material to be cut is rotated about its own axis, and the cutting tip, in which the first cutting edge is arranged so as to face the portion corresponding to the first surface, is directed toward the portion corresponding to the neck portion. By moving the portion corresponding to the first surface, the portion corresponding to the first surface is cut by the first cutting edge, and the portion corresponding to the second surface is cut by the second cutting edge.
Manufacturing method of the member to be processed. The member to be processed is a main metal fitting used for manufacturing a spark plug.
The method for manufacturing a member to be processed according to claim 5.

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