Tool bit and cutting tool

Abstract

The present invention provides a cutting head capable of preventing chip clogging during machining, and a cutting tool having the same. The cutting head 30 includes a first surface 310 which is a portion that comes into contact with a main body 20 when the cutting head 30 is provided on the main body 20 of a cutting tool 10, a second surface 320 which is located on the opposite side of the first surface 310, a front end portion 330 which connects the first surface 310 and the second surface 320 and is provided with a cutting edge 331, and a rear end portion 340 which is located on the opposite side of the front end portion 330. A recessed portion 321 which is recessed toward the first surface 310 is formed in a portion of the second surface 320 on the side of the rear end portion 340.

Description

Technical Field

[0001] This invention relates to a cutting head and a cutting tool having the cutting head. Background Technology

[0002] A machining method called "BTA" (Boring & Trepanning Association, internal chip removal deep hole drilling) is known for forming deep holes in the workpiece. As described in Patent Document 1 below, in BTA, fluid flowing towards the cutting edge is supplied through the gap between the inner circumferential surface of the hole and the outer circumferential surface of the cutting tool. This fluid, along with the chips generated during machining, is discharged to the outside through a discharge hole formed inside the cutting tool.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-276056 (JP2007276056A)

[0006] Technical issues

[0007] In BTA cutting tools, a cutting edge is typically located near the inlet of the discharge port. Therefore, the inlet of the discharge port is narrowed by the cutting edge, making it difficult for the fluid containing chips to flow into the discharge port. In some cases, chips may clog the inlet of the discharge port.

[0008] The purpose of this invention is to provide a cutting head that can prevent chip clogging during machining, and a cutting tool having the cutting head. Summary of the Invention

[0009] The present invention provides a cutting head for a cutting tool, comprising: a first surface, which is a portion that abuts against the main body when the cutting head is mounted on the main body of the cutting tool; a second surface, located on the opposite side of the first surface; a front end portion, which connects the first surface and the second surface and is provided with a cutting edge; and a rear end portion, located on the opposite side of the front end portion, wherein a recess is formed on the rear end portion side of the second surface that is recessed toward the first surface.

[0010] When a cutting head with this structure is mounted on a cutting tool, the cross-sectional area of ​​the flow channel through which the fluid containing chips flows is correspondingly increased due to the recess. The cutting head does not narrow the inlet of the discharge port; a portion of the fluid is smoothly guided to the discharge port through the recess. Therefore, chip blockage near the discharge port inlet is prevented.

[0011] More preferably, when the width direction is perpendicular to the direction from the front end to the rear end and parallel to the first surface, the recess is provided in the second surface in the range other than the two ends in the width direction.

[0012] More preferably, the recess approaches the first surface side as it moves toward the rear end side.

[0013] The cutting tool provided by the present invention includes a body and a cutting head disposed on the body. The body has a discharge hole extending along the rotation center axis for discharging fluid. The cutting head includes a first surface abutting the body, a second surface located on the opposite side of the first surface, a front end portion connecting the first surface and the second surface and provided with a cutting edge, and a rear end portion located on the opposite side of the front end portion. A recess is formed on one side of the rear end portion of the second surface, which is recessed toward the first surface.

[0014] In cutting tools with this structure, the cross-sectional area of ​​the flow channel through which the chip-containing fluid flows is correspondingly increased due to the recess. The tool tip does not narrow the inlet of the discharge port, and a portion of the fluid is smoothly guided to the discharge port through the recess. Therefore, chip blockage near the discharge port inlet is prevented.

[0015] More preferably, there is no height difference between the inner surface of the recess and the inner surface of the discharge hole when they are connected at the junction.

[0016] More preferably, the inner surface of the recess and the inner surface of the discharge hole are smoothly connected at the junction.

[0017] The present invention provides a cutting head that can prevent chip clogging during machining, and a cutting tool equipped with the cutting head. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall structure of the cutting tool provided in this embodiment.

[0019] Figure 2 A schematic diagram depicting the cutting tool provided in this embodiment as viewed from the front end along the rotation center axis.

[0020] Figure 3 This is a schematic diagram of the cutting head of the cutting tool provided in this embodiment.

[0021] Figure 4 for Figure 1 A partial cross-sectional diagram of section IV-IV.

[0022] Explanation of main component symbols

[0023] Cutting tools 10

[0024] Main body 20

[0025] 30 blades

[0026] Page 1, 310

[0027] Page 2, 320

[0028] Recess 321

[0029] Front end 330

[0030] Rear end 340 Detailed Implementation

[0031] The following description of this embodiment will be based on the accompanying drawings. To facilitate understanding, identical components in each figure will be labeled with the same symbols as much as possible, and repeated descriptions will be omitted.

[0032] In this embodiment, the cutting tool 10 is a BTA machining cutting tool used for deep hole machining. For example... Figure 1 As shown, the cutting tool 10 includes a body 20, a cutting head 30, and a guide block 40.

[0033] The main body 20 almost constitutes the entirety of the cutting tool 10 and is made of steel. The main body 20 consists of two parts: the drill bit 21 and the drill tube 22.

[0034] The drill bit 21 is a component located at the front end of the main body 20, and is equipped with the cutting head 30 described below. The drill bit 21 is approximately cylindrical, as shown below. Figure 1 As shown, a portion of its side has a notch. A mounting base 210 for mounting the drill bit 30 is provided at the notch. The drill bit 21 is screwed into the front end of the drill tube 22, thus becoming integral with the drill tube 22.

[0035] The drill pipe 22 is a component located at the rear end of the main body 20. Like the drill bit 21, the drill pipe 22 is approximately cylindrical. The side of the drill pipe 22 opposite to the drill bit 21 (i.e., the rear end) is held by a machine tool (not shown) and driven by the machine tool to rotate about the rotation axis AX during machining. Furthermore, the rotation axis AX coincides with the central axis of both the approximately cylindrical drill bit 21 and the drill pipe 22. The drill bit 21 and the drill pipe 22 are arranged along the rotation axis AX. Figure 1 and Figure 2 The arrows indicate the direction of rotation of the main body 20 during the processing.

[0036] A discharge hole 23 is formed on the body 20. The discharge hole 23 is a hole for guiding and discharging coolant supplied along the outer peripheral surface of the body 20, along with chips, to the outside. The discharge hole 23 extends along the rotation central axis AX and is formed to penetrate the entire body 20. The discharge hole 23 is approximately cylindrical, and its central axis is substantially aligned with the rotation central axis AX. However, in the portion near the cutter head 30, the central axis of the discharge hole 23 is inclined relative to the rotation central axis AX. Specifically, as it approaches the side where the cutter head 30 is located, the inner surface of the discharge hole 23 is inclined toward the rotation central axis AX.

[0037] The cutting head 30 is a component with a cutting edge 331 formed thereon. In this embodiment, the cutting head 30 is entirely formed of cemented carbide. The material of at least the cutting edge 331 portion of the cutting head 30 may include any of the following: for example, hard materials containing cermet, ceramic, and cubic boron nitride sintered bodies (with a coating layer formed by PVD (physical vapor deposition) or CVD (chemical vapor deposition) on the surface of these hard materials), or sintered bodies containing single-crystal diamond or diamond, etc. As mentioned above, the cutting head 30 is disposed on the mounting base 210 of the body 20. In this embodiment, the cutting head 30 is brazed to the mounting base 210. Alternatively, the cutting head 30 may be fastened to the mounting base 210 by screws or the like, and may be removed and replaced from the mounting base 210. That is, the cutting head 30 may be designed as a so-called "cutting insert".

[0038] The guide block 40 is a component that suppresses deformation of the main body 20 by abutting against the inner surface of the hole during machining. Hereinafter, the hole formed in the workpiece material when the cutting tool 10 rotates is referred to as a "machining hole". In this embodiment, two guide blocks 40 are provided. Because of the guide blocks 40, machining can be performed while maintaining the straightness and roundness of the machining hole.

[0039] When performing BTA machining on the workpiece using cutting tool 10, fluid coolant is supplied from the outside through the gap between the inner circumferential surface of the machining hole and the outer circumferential surface of the body 20. After reaching the cutting edge 331 on the front end side, the coolant flows into the discharge hole 23 of the body 20 along with the chips generated during machining. After flowing through the discharge hole 23 to the rear end side, the coolant is discharged to the outside.

[0040] The specific structure of the cutter head 30 is described below. For example... Figure 3 As shown, the cutter head 30 includes a first surface 310, a second surface 320, a front end portion 330, and a rear end portion 340.

[0041] The first surface 310 is the rearward side facing the direction of rotation when the cutter head 30 is mounted on the main body 20, and it is the portion that abuts against and is restricted by the mounting base 210 of the main body 20. In this embodiment, almost the entire first surface 310 is brazed to the mounting base 210. In addition to the first surface 310, other surfaces of the cutter head 30 (e.g., the inner and rearward side surfaces) may also be brazed to the main body 20.

[0042] The second surface 320 is the front side facing the direction of rotation when the cutter head 30 is mounted on the main body 20. That is, the second surface 320 is located on the opposite side of the first surface 310. For example... Figure 2 As shown, the second surface 320 is a surface that is mostly parallel to the first surface 310. The second surface 320 can also be a surface located on the side of the direction of travel when the main body 20 rotates around the rotation center axis AX.

[0043] The front end portion 330 connects the first surface 310 and the second surface 320, and is located at the foremost end when the cutter head 30 is mounted on the main body 20. The front end portion 330 is provided with a cutting edge 331 for machining the workpiece. For example... Figure 1 and Figure 3 As shown, the front end portion 330 is not a single plane, but rather a multi-step structure, with a cutting edge 331 on each step. The shape of the front end portion 330 and the shape of the cutting edge 331 may differ from those described herein.

[0044] The rear end portion 340 is the part connecting the first surface 310 and the second surface 320, and is located on the opposite side of the front end portion 330 along the rotation center axis AX. The rear end portion 340 is substantially perpendicular to the first surface 310 and has a flat surface.

[0045] A recess 321 is formed on the second surface 320 of the cutter head 30, which is recessed toward the first surface 310. The recess 321 is formed on the rear end portion 340 side of the second surface 320. Specifically, the recess 321 extends from the middle position of the second surface 320 to the end position on the rear end portion 340 side along the rotation center axis AX.

[0046] Here, Figure 3 The direction indicated by the middle arrow AR is defined as the "width direction" of the cutter head 30. The width direction is perpendicular to the direction from the front end 330 towards the rear end 340 (also referred to as the direction along the rotation center axis AX) and parallel to the first face 310. For example... Figure 3 As shown, the recess 321 is provided in the second surface 320 in the area excluding the two ends in the width direction. Therefore, in this embodiment, the recess 321 is formed as a groove extending toward the rear end 340.

[0047] Figure 4 It shows Figure 1 A partial cross-section of the cutter head 30 and the main body 20 (drill bit 21) in section IV-IV. For example... Figure 4 As shown, the inner surface of the recess 321 approaches the first surface 310 towards the rear end 340 side, forming a surface inclined relative to the rotation center axis AX.

[0048] exist Figure 4 In the diagram, "BD" marks the boundary between the inner surface of the recess 321 and the inner surface of the discharge hole 23. This portion will also be referred to as "the boundary portion BD" below. The boundary portion BD can also be the boundary between the recess 321 and the rear end 340, or it can be the downstream end of the recess 321 in the direction of coolant flow.

[0049] like Figure 4As shown, there is no height difference between the inner surface of the recess 321 and the inner surface of the discharge hole 23 when they connect at the junction BD. "No height difference" means that, in Figure 4 In the cross-section, the coordinates of the inner surface of the recess 321 and the coordinates of the inner surface of the discharge hole 23 are approximately or completely consistent at the junction BD. The deviation between these coordinates is preferably controlled to be less than 0.1 mm. "Coordinates" refers to, for example, in... Figure 4 In the cross-section, the distance between the point and the arbitrarily set origin. Further, in this embodiment, the inner surface of the recess 321 and the inner surface of the discharge hole 23 are smoothly connected at the junction portion BD. "Smooth connection" means that in... Figure 4 In the cross-section, the inclination of the inner surface of the recess 321 and the inclination of the inner surface of the discharge hole 23 are consistent at the junction BD. It should be noted that, strictly speaking, at the junction BD, the inner surfaces of the recess 321 and the discharge hole 23 may have a small chamfer, etc., but ignoring the shape of such chamfer, etc., the meaning of each term is defined as described above.

[0050] The effects of the aforementioned structure on the cutting head 30 will now be explained. Generally, in cutting tools used for BTA machining, as in this embodiment, the cutting head is often positioned near the inlet of the discharge port. Therefore, due to the narrowing of the cutting head, the inlet of the discharge port may be difficult for the molten metal containing chips to flow into it. In some cases, chips may become trapped at the inlet of the discharge port.

[0051] Therefore, in the cutting tool 10 of this embodiment, by forming a recess 321 on the second surface 320 of the cutting head 30, a wider path for the coolant to flow into the discharge hole 23 is ensured. Since the inlet of the discharge hole 23 is not narrowed by a part of the cutting head 30, chip blockage during machining can be prevented.

[0052] The inner surface of the recess 321 is a smooth bevel with no height difference in the middle. Furthermore, the inner surface of the recess 321 and the inner surface of the discharge hole 23 are smoothly connected at the junction BD without any height difference. This structure prevents coolant and chips guided by the recess 321 from accumulating in the middle of the recess 321 or at the junction BD. Therefore, chip clogging can be prevented more reliably.

[0053] Furthermore, provided that the flow of coolant and chips can be sufficiently ensured, i.e., without the aforementioned problems such as stagnation, there can be a height difference at the junction BD, and the inclination of the inner surface can vary along the junction BD. Additionally, the inner surface of the recess 321... Figure 4 The cross-section may not be straight as in this embodiment; part or all of the inner surface may be curved, or there may be a height difference in the middle of the inner surface.

[0054] As previously described, the recess 321 is provided in the second surface 320, excluding the two ends in the width direction. Therefore, at the aforementioned "two ends," there is no height difference between the cutter head 30 and the body 20, and they are smoothly connected. Consequently, the formation of the recess 321 does not increase the height difference in the coolant flow path.

[0055] The embodiments described above with reference to specific examples are as follows. However, this disclosure is not limited to these specific examples. Any appropriate design modifications made to these specific examples by those skilled in the art, provided they possess the features of this disclosure, should be included within the scope of this disclosure. The various components, their configurations, conditions, shapes, etc., of the foregoing specific examples can be appropriately modified and are not limited to the examples shown. The various elements of the foregoing specific examples can be appropriately combined without causing technical inconsistencies.

Claims

1. A cutting head for a cutting tool, comprising: The first side is the portion that abuts against the main body when the cutting head is mounted on the main body of the cutting tool; The second surface is located on the opposite side of the first surface; the front end connects the first surface and the second surface and is provided with a cutting edge; the rear end is located on the opposite side of the front end, and a recess is formed on the rear end side of the second surface that is recessed toward the first surface. Wherein, when the width direction is perpendicular to the direction from the front end to the rear end and parallel to the first surface, on the second surface, inclined surfaces are provided on both sides of the recess in the width direction, and the inclined surfaces gradually approach the first surface towards the rear end.

2. The cutting head according to claim 1, wherein, The recess is located in the second surface, excluding the two ends in the width direction.

3. The cutting head according to claim 1, wherein, The recess approaches the first surface side as it moves toward the rear end side.

4. A cutting tool, comprising a body and a cutting head disposed on the body, wherein the body has a discharge hole extending along a rotational central axis for discharging fluid, the cutting head comprising a first surface abutting the body, a second surface located on the opposite side of the first surface, a front end portion connecting the first surface and the second surface and provided with a cutting edge, and a rear end portion located on the opposite side of the front end portion, wherein a recess is formed on one side of the rear end portion in the second surface, recessed toward the first surface; in, When the width direction is perpendicular to the direction from the front end to the rear end and parallel to the first surface, on the second surface, inclined surfaces are provided on both sides of the recess in the width direction, and the inclined surfaces gradually approach the first surface towards the rear end.

5. The cutting tool according to claim 4, wherein, There is no height difference between the inner surface of the recess and the inner surface of the discharge hole when they are connected at the junction.

6. The cutting tool according to claim 5, wherein, The inner surface of the recess and the inner surface of the discharge hole are smoothly connected at the junction.

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