JP3161422U - Grinding tool - Google Patents

Abstract

An object of the present invention is to provide a grinding tool capable of grinding a cemented carbide workpiece and finishing the corners of the workpiece without leaving an unground portion. A columnar base metal, a columnar portion 13 joined to the tip of the base metal, and a plurality of grinding portions 15 provided on a tip surface 14 of the columnar portion 13 are provided. The grinding part 15 is a grinding tool composed of an integral polycrystalline sintered diamond layer 16, and the grinding part 15 includes a belt-like part 18 extending radially from the center 17 of the tip surface 14 of the cylindrical part, and the belt-like part. The blade portion 20 extends from the portion 18 and protrudes from the outer peripheral surface 19 of the cylindrical portion. [Effects] The corners of the cemented carbide material can be finished without leaving unground parts, and the chip discharge efficiency can be increased. [Selection] Figure 2

Description

  The present invention relates to an improvement of a grinding tool.

  Conventionally, as a fine grinding tool, a grinding tool having a grinding portion made of a cBN (cubic boron nitride) sintered body has been widely used. Although this cBN sintered body is suitable for grinding a high hardness steel, there is a problem in that it is worn away immediately when the work material is a cemented carbide. However, in recent years, there has been an increasing demand for grinding cemented carbide, and a grinding tool that can meet this demand has been proposed (see, for example, Patent Document 1 (FIG. 3)).

Patent document 1 is demonstrated based on the following figure.
FIG. 9 is a diagram for explaining the basic configuration of the prior art, and the tip of the grinding tool is composed of a polycrystalline diamond layer 100. The polycrystalline sintered diamond layer 100 includes a cylindrical portion 101 and a belt-like or columnar grinding portion 102 provided on the tip surface (lower surface in the drawing) of the cylindrical portion 101.

  However, when the flat surface 104 of the work material 103 is ground, there is a disadvantage that the flat surface 104 cannot be completely ground at the corner portion 106 with the vertical surface 105 rising vertically from the flat surface 104. That is, since the outer peripheral surface 107 of the polycrystalline diamond layer 100 interferes with the vertical surface 105 and the grinding portion 103 cannot be brought close to the vertical surface 105 (the grinding portion 102 cannot be cut into the corner portion 106), An unground portion 108 remains (at the left end in the figure).

  Therefore, a grinding technique that does not leave an unground portion at the corner of the work material is desired.

JP 2009-262286 A

  This invention makes it a subject to provide the grinding tool which can finish the corner | angular part of a workpiece, without leaving an unground part.

The invention according to claim 1 includes a columnar base metal, a cylindrical part joined to the tip of the base metal, and a plurality of grinding parts provided on a tip surface of the cylindrical part, and the cylindrical part And the grinding part, in a grinding tool composed of an integral polycrystalline sintered diamond layer,
The grinding part is a band-like part extending in the radial direction from the center of the tip surface of the cylindrical part,
The blade portion extends from the belt-like portion and protrudes from the outer peripheral surface of the cylindrical portion.

  The device according to claim 2 is characterized in that the belt-like portion has an arc shape.

In the invention according to claim 1, the grinding part constituting the polycrystalline sintered diamond layer includes a belt-like part extending in a radial direction from the center of the front end face of the cylindrical part, and a projection extending from the outer peripheral surface of the cylindrical part extending from the belt-like part. And a blade portion to be made.
Since the belt-like part and the blade part constituting the grinding part are polycrystalline sintered diamond layers, the cemented carbide can be ground.

  Moreover, since the blade part protrudes from the outer peripheral surface of the cylindrical part, even if the blade part is cut into the corner part when grinding the flat surface of the work material, it is constant between the outer peripheral surface and the vertical surface of the cylindrical part. Therefore, the outer peripheral surface of the cylindrical portion does not interfere with the vertical surface. Since the cylindrical portion does not interfere with the vertical surface, it can be ground to the end of the plane with the blade portion. Therefore, an unground portion does not remain at the corner of the work material.

  Thus, according to the present invention, it is possible to grind cemented carbide and finish the corner of the work material without leaving an unground part.

  Furthermore, since the chips ground by the blade portion are discharged from between the blade portion and the blade portion, they do not accumulate near the tip surface of the cylindrical portion, and the workability of grinding is improved.

In the device according to claim 2, the belt-like portion has an arc shape.
The blade receives resistance from the work material during grinding. This resistance force is transmitted from the blade portion to the strip portion. When this resistance force is transmitted to the belt-like portion, if the belt-like portion has an arc shape, the length of the belt-like portion can be secured longer than the case where the belt-like portion is linear (the joining of the belt-like portion and the cylindrical portion). Therefore, the strength of the belt-shaped portion against the resistance force from the work material is increased.

  Further, during grinding, the chips accumulated between the plurality of strip portions are blown away by receiving centrifugal force due to rotation of the cylindrical portion, and are discharged to the outside from between the blade portions. At this time, in addition to the centrifugal force directed in the radial direction of the cylindrical portion, the chip also receives a frictional force in the circumferential direction due to the rotation of the cylindrical portion.

  Accordingly, since the chip draws an arc-shaped trajectory relative to the tip surface of the cylindrical portion, the chip jumps along the band-shaped portion by forming the strip-shaped portion into an arc shape along the trajectory. It will be discharged smoothly. Therefore, the chip discharge efficiency can be further increased.

1 is a perspective view of a grinding tool according to the present invention. FIG. 2 is a view taken in the direction of arrow 2 in FIG. 1. FIG. 3 is a view taken in the direction of arrow 3 in FIG. 1. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. It is a perspective view explaining the formation method of a grinding part. It is principal part sectional drawing of FIG. It is a figure explaining the effect | action of a grinding part. It is a figure which shows the example of a change of FIG. It is a figure explaining the conventional polycrystalline sintered diamond layer.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The drawings are viewed in the direction of the reference numerals.

An embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the grinding tool 10 is used as an end mill, and includes a cylindrical shank 11, a cylindrical base metal 12 joined to the tip of the shank 11, and the base metal 12. It consists of the cylindrical part 13 joined previously, and the some grinding part 15 provided in the front end surface 14 of this cylindrical part. The cylindrical portion 13 and the grinding portion 15 are constituted by an integral polycrystalline sintered diamond layer 16.

  For example, the overall length L of the grinding tool 10 is 20 to 60 mm, the outer diameter D of the shank 11 is 2 to 6 mm, and the outer diameter d of the base metal 12 and the polycrystalline sintered diamond layer 16 is 0.1 to 8.0 mm. It is.

  The polycrystalline sintered diamond layer 16 is formed by mixing fine diamond particles with Ni, Co, etc., and sintering at high temperature and high pressure, and is generally called PCD (Polycrystalline Diamond). Compared with the single crystal diamond layer, since the diamond powder is inexpensive, the polycrystalline sintered diamond layer 16 can be manufactured at low cost.

  As shown in FIG. 2, the grinding part 15 includes a band-like part 18 extending radially from the center 17 of the tip surface 14 of the cylindrical part, and a blade part extending from the belt-like part 18 and projecting from the outer peripheral surface 19 of the cylindrical part. 20. The number of the plurality of grinding parts 15 (12 twisted blades in FIG. 2) is arbitrary as long as it is two or more, but it is preferable to arrange them at equal intervals in the circumferential direction.

  The strip-shaped portion 18 has an arc shape. Specifically, the belt-like portion 18 extends from the proximal end located on the center 17 side of the distal end surface while being slightly bent in the tool rotation direction (arrow (2)) rather than the radial direction (arrow (1)). Reaches the outer peripheral surface 19 of the cylindrical portion.

  The blade portion 20 is a portion obtained by further extending the belt-like portion 18 outward from the outer peripheral surface 19, and the tip of the blade portion 20 protrudes from the outer peripheral surface 19 by a distance L <b> 1. A cutting edge 21 for grinding the work material in the direction of rotation of the tool (arrow (2)) is formed on the side of the blade section 20.

  As shown in FIG. 3, one side of the cutting edge 21 is formed as a rake face 22 that scoops chips when grinding, and the other side of the cutting edge 21 extends from the work material to the blade portion. It is formed as a main flank 23 that allows 20 to escape.

  As shown in FIG. 4, when the blade part 20 is moved in the axial direction of the tool (arrow (3)) and is ground, a secondary flank 24 is formed to allow the blade part 20 to escape from the grinding object.

Next, an example of a method for forming the cylindrical portion 13, the belt-like portion 18, and the blade portion 20 described above will be described.
As shown in FIG. 5, first, from a cylindrical shank 11, a base metal 12 joined to the tip of the shank 11, and a polycrystalline sintered diamond layer 16 joined to the tip of the base metal 12. An intermediate product 30 is prepared. The polycrystalline sintered diamond layer 16 here is not provided with a grinding part (FIG. 2, reference numeral 15), and the outer diameter of the polycrystalline sintered diamond layer 16 is a cylindrical part (FIG. 2, reference numeral Larger than 13).

  This intermediate product 30 is placed on a V block 31 and lightly held by a roller 32. The number of V blocks 31 may be one. Next, the collet chuck 33 is connected to the shank 11. The collet chuck 33 is rotated by a servo motor 36 via a rotating shaft 34 and a flexible coupling 35. The flexible coupling 35 has an effect of transmitting a rotational force and has a role of preventing the vibration of the motor shaft of the servo motor 36 from being transmitted to the rotating shaft 34.

For electric discharge machining, a first discharge electrode 37A that faces the outer peripheral surface of the polycrystalline sintered diamond layer 16 and a second discharge electrode 37B that faces the tip surface of the polycrystalline sintered diamond layer 16 are prepared.
Then, the first discharge electrode 37A is faced to the polycrystalline sintered diamond layer 16, and the outer peripheral surface of the polycrystalline sintered diamond layer 16 is subjected to electric discharge machining while being rotated by the servo motor 36, so that the blade portion (FIG. 2, In addition to projecting the reference numeral 20), the outer peripheral surface of the polycrystalline sintered diamond layer 16 is cut to form a cylindrical portion (FIG. 2, reference numeral 13) with a predetermined outer dimension.

  Alternatively, the second discharge electrode 37B faces the front end surface of the polycrystalline sintered diamond layer 16 in a stationary state, and the front end surface of the polycrystalline sintered diamond layer 16 has a band-like portion (FIG. 2, reference numeral 18) and a blade portion (FIG. 2, sharpen so that 20) remains.

  By the way, the collet chuck 33 grips the shank 11 by bringing the divided pieces to the center. There is inevitably a slight misalignment between the divided pieces. As a result, the shank 11 swings during rotation. As it is, the finishing accuracy of the outer peripheral surface of the cylindrical portion (FIG. 2, reference numeral 19) and the blade portion (FIG. 2, reference numeral 20) is affected. The countermeasure will be described next.

  As shown in FIG. 6, since the shank 11 is positioned by the V block 31, there is no fear that the intermediate product 30 swings in the direction perpendicular to the axis. Since it is conceivable that the shank 11 is lifted from the V block 31 when the shank 11 is rotated, the roller 32 prevents the lift. Thus, the shank 11 can be rotated without shaking. As a result, the outer peripheral surface (FIG. 2, reference numeral 19) and the blade part (FIG. 2, reference numeral 20) of the cylindrical portion can be determined accurately.

The operation of the grinding tool described above will be described next.
Since the belt-like portion 18 and the blade portion 20 constituting the grinding portion 15 are the polycrystalline sintered diamond layer 16, it is possible to grind the cemented carbide work material.

  As shown in FIG. 7A, the blade portion 20 protrudes from the outer peripheral surface 19 of the cylindrical portion, and when the flat surface 41 of the work material 40 is ground, the outer peripheral surface 19 of the cylindrical portion and the blade portion 20 A distance L1 is ensured between the tip. Since the distance L1 is ensured, the outer peripheral surface 19 of the cylindrical portion does not interfere with the vertical surface 42 even if it is cut into the corner 43 of the vertical surface 42. Therefore, since it can grind to the edge (left edge in a figure) of the plane 41 with the blade part 20, an unground part does not remain in the corner | angular part 43. FIG.

  Further, as shown in FIG. 7 (b), the distance L1 is ensured between the outer peripheral surface 19 of the cylindrical portion and the tip of the blade portion 20, whereby the vertical surface 42 is moved in the axial direction of the tool (arrow (3)). ) Can be ground along. After the plane (FIG. 7 (a) reference numeral 41) is cut to the end, the vertical surface 42 is ground along the axial direction of the tool (arrow (3)), thereby making the corner of the work material 40 more perpendicular. Can be finished.

  In this way, it is possible to grind the cemented carbide and finish the corner of the work material without leaving an unground part.

  Further, as shown in FIG. 2, the chips ground by the blade portion 20 are discharged from between the two adjacent blade portions 20 to the outer peripheral surface 19 side of the column portion, so that the column portion 13. Therefore, the workability of grinding is improved.

In addition, since the belt-like portion 18 has an arc shape, the following effects are exhibited.
The blade 20 receives a resistance force from the work material during grinding. This resistance force is transmitted from the blade portion 20 to the belt-like portion 18. When this resistance force is transmitted to the belt-like portion 18, if the belt-like portion 18 has an arc shape, the length of the belt-like portion 18 can be secured longer than the case where the belt-like portion 18 is linear (the belt-like portion 18 and the belt-like portion 18). Therefore, the strength of the band-shaped portion 18 against the resistance force from the work material is increased.

  In addition, during the grinding, chips accumulated between the plurality of belt-like portions 18 are blown away by the centrifugal force generated by the rotation of the cylindrical portion 13 and discharged from between the blade portions 20. At this time, in addition to the centrifugal force directed in the radial direction (arrow (1)) of the cylindrical portion 13, the chips are simultaneously subjected to the frictional force in the circumferential direction (arrow (2)) due to the rotation of the cylindrical portion 13.

  Therefore, since the chip draws an arc-shaped trajectory (indicated by a white arrow in FIG. 2) relative to the rotating front end surface 14, the belt-shaped portion 18 is arc-shaped along the trajectory. Thus, the chips fly along the strip 18 and are smoothly discharged. Therefore, the chip discharge efficiency can be further increased.

Next, a modified example of the embodiment will be described with reference to the drawings.
FIG. 8 is a diagram showing a modified example of FIG. The difference from FIG. 2 is that the strip 18B and the blade 20B extending in the radial direction are formed in a straight line. The rest of the configuration is the same as that in FIG. 2, and the detailed description is omitted by using the reference numerals in FIG. 2.

  Since the belt-like portion 18B and the blade portion 20B are linear, electric discharge machining by the second discharge electrode is facilitated, and the machining cost can be reduced.

  In addition, although this invention was applied to the grinding tool for grinding a cemented carbide in embodiment, it is applicable also to the grinding tool for grinding high-hardness steel, and is applied to a general fine grinding tool. There is no problem.

  The grinding tool of the present invention is suitable for a fine grinding tool for grinding cemented carbide.

  DESCRIPTION OF SYMBOLS 10 ... Grinding tool, 12 ... Base metal, 13 ... Cylindrical part, 14 ... End face of cylindrical part, 15 ... Grinding part, 16 ... Polycrystalline sintered diamond layer, 17 ... Center of front end face, 18 ... Strip-like part, 19 ... the outer peripheral surface of the column part, 20 ... the blade part.

Claims (2)

A cylindrical base metal (12), a cylindrical part (13) joined to the tip of the base metal (12), and a plurality of grinding parts (14) provided on the tip surface (14) of the cylindrical part (13) 15), and the cylindrical part (13) and the grinding part (15) are a grinding tool (10) composed of an integral polycrystalline sintered diamond layer (16).
The grinding part (15) includes a band-like part (18) extending in a radial direction from the center (17) of the tip surface (14) of the cylindrical part (13),
A grinding tool comprising: a blade portion (20) extending from the strip portion (18) and projecting from the outer peripheral surface (19) of the cylindrical portion (13).   The grinding tool according to claim 1, wherein the belt-like portion has an arc shape.

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