A tool bit of a tool bit replaceable cutting tool

Abstract

This invention provides a tool head for a replaceable cutting tool. The tool head's construction is based on a novel concept that enables easy external measurement while maintaining cutting performance. A tool head 20 is an approximately cylindrical tool head for a replaceable cutting tool. A cutting insert 30 is detachably mounted on a insert mounting seat of the tool head 20, and the tool head 20 can be securely fastened to a tool holder held on a machine tool. The tool head 20 has points, lines, or surfaces defining reference surfaces 22 (22A, 22B, 22C), said reference surfaces 22 being a predetermined length from a predetermined position of the cutting edge 31 of the cutting insert 30.

Description

Technical Field

[0001] This invention relates to a tool head for a replaceable cutting tool. Background Technology

[0002] In cutting tools installed on machine tools used for turning (machining using machine tools such as lathes), a near-cylindrical tool holder (also referred to as a "circular tool holder" in this specification) is sometimes used. The circular tool holder has a plane (reference plane) formed by cutting off a portion of its outer surface. The circumferential (rotational) orientation of the circular tool holder is determined by pressing this plane (reference plane) with screws or the like when the circular tool holder is mounted on the machine tool. When performing machining operations such as boring, external turning, and end-face machining using the circular tool holder, machining preparation (also called "preparation") is required. This "preparation" generally includes the following operations: (1) mounting the circular tool holder cutting tool on the machine tool; and (2) measuring the cutting edge position in this state. Machining can only proceed after these preparatory operations are completed. Therefore, if this preparation takes time, the time the machine tool cannot operate (also called "downtime") increases, and production efficiency actually decreases.

[0003] To reduce the aforementioned downtime, one method proposed in the prior art is to use a tool-changeable cutting tool. This utilizes a tool-changeable cutting tool (where the tool head with a cutting edge (cutting) holder and the tool holder with a retained part on the machine tool are separate components, and the tool head can be removed while the tool holder is on the machine tool) (see, for example, Patent Documents 1, 2, etc.). By adding a preparation stage, operations can be performed outside the machine tool, thereby shortening downtime. For example, the operation is performed according to the following procedure: (1') with the tool holder mounted on the machine tool, the tool head is removed from the tool holder, and the cutting edge position is measured outside the machine tool (referred to as "outside-machine tool measurement"); (2') the tool head is mounted on the tool holder. In fact, from the perspective of simplifying installation, this method saves time. From this perspective, a mechanism for easily and accurately securing the tool head to the tool holder has been proposed in the prior art. Using this mechanism, the cutting tool can be disassembled (i.e., the tool head can be removed from the tool holder), and after external measurement is performed on the machine tool, the tool head can be easily installed on the tool holder, thereby reducing downtime.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Publication No. 2012-522651

[0007] Patent Document 2: Japanese Patent Publication No. 2014-524357

[0008] Technical issues

[0009] While existing technologies have proposed methods as described above—namely, disassembling traditional cutting tools and enabling external measurement by easily and precisely securing the tool head to the tool holder—no proposals or technologies have been made from the perspective of easily performing external measurements. In particular, there are currently no proposals or technologies that allow for easy external measurements while maintaining or achieving equivalent cutting performance of the tool head.

[0010] Therefore, the object of the present invention is to provide a tool head for a replaceable cutting tool, the tool head being constructed based on a novel concept that enables easy external measurement while maintaining cutting performance. Summary of the Invention

[0011] One embodiment of the present invention provides a tool head, which is an approximately cylindrical tool head of a tool head replaceable cutting tool, wherein the cutting insert is detachably mounted on the tool head's insert mounting seat, and the tool head can be fastened to a tool holder held on a machine tool, wherein the tool head forms points, lines or surfaces defining a reference surface, the reference surface being a predetermined length from a predetermined position of the cutting edge of the cutting insert.

[0012] In other words, in the prior art, cutting tools have a reference surface set on the tool holder. It can be said that the prior art only improves upon this premise. In response to this, the tool head provided in this disclosure is based on the following novel concept: the reference surface, which was previously only located on the approximately cylindrical tool holder, is located on the side of the tool head. This new structure of the tool head makes it possible to perform external measurements using only the tool head. Performing external measurements using only the tool head means that it is not necessary to prepare a separate tool holder with a reference surface outside the machine tool beforehand, as is the case with the prior art.

[0013] When forming a reference surface on the tool tip itself, it is advisable to remove a portion of the outer periphery of the tool tip to form a flat surface. In the tool tip with the above-described structure provided in this disclosure, even if a portion is removed in this manner, the cutting performance will not be significantly affected. That is, in the structure of the prior art, for example, a reference surface is formed by removing a portion of the outer surface of an approximately cylindrical tool holder (round tool holder). The removed portion has a significant impact on the rigidity and deflection of the tool holder. In view of this, in the structure of this disclosure, a fastening mechanism is used to fasten the tool tip to the front end of the tool holder, and the aforementioned impact is relatively small.

[0014] In the tool head of the embodiment described above, a tool holder reference surface is formed on the outer periphery of the tool holder by cutting off a portion of the outer periphery of the tool holder. The reference surface of the tool head can be formed parallel to or perpendicular to the tool holder reference surface.

[0015] In the tool head of the embodiment described above, the reference surface may be formed on the back side of the blade mounting seat in the tool head.

[0016] In the tool head of the embodiment described above, the reference surface may be formed on the side opposite to the predetermined position of the cutting edge relative to the central axis of the tool head.

[0017] In the tool head of the embodiment described above, a first reference surface can be formed on the back side of the blade mounting seat in the tool head as a reference surface, and a second reference surface can be formed on the side opposite to the predetermined position of the cutting edge relative to the central axis of the tool head.

[0018] In the tool head of the embodiment described above, the central axis is located between the first reference plane and the third reference plane, and the third reference plane, which is parallel to the first reference plane, is formed on the opposite side of the first reference plane.

[0019] In the tool head of the embodiment described above, the predetermined position can be the cutting edge of the cutting edge.

[0020] The tool head of the embodiment described above also includes a fastening mechanism for securing to the tool holder, the size of which, when viewed along the central axis of the tool head from the front end side having the blade seat, is such that it is not located outside the reference plane.

[0021] In the tool head of the embodiment described above, the reference surface can be formed as a plane.

[0022] In the tool head of the embodiment described above, the reference surface can be formed to allow the tool head to stand upright on a flat placement surface. Attached Figure Description

[0023] Figure 1 Example diagram of the tool holder and tool head of a tool with interchangeable tool heads.

[0024] Figure 2A This is a perspective view of a tool tip according to one embodiment of the present invention.

[0025] Figure 2B This is a top view (viewed from the third reference plane) of a tool tip according to one embodiment of the present invention.

[0026] Figure 2C This is a side view of the tool tip in one embodiment of the present invention (viewed from the second reference plane).

[0027] Figure 3A This is a schematic diagram of a tool head viewed from the front end along the central axis in one embodiment of the present invention.

[0028] Figure 3B This is a schematic diagram of a tool head viewed from the end side along the central axis in one embodiment of the present invention.

[0029] Figure 4 This is a perspective view illustrating the position measurement of the cutting edge of a tool head along its width direction from a reference plane in that direction.

[0030] Figure 5 This is a perspective view illustrating the position measurement of the cutting edge of a tool head along the height direction from a reference plane in the height direction.

[0031] Figure 6 This diagram illustrates a series of operations from removing the tool head from the tool holder to measuring the cutting edge position using the tool head alone, in comparison with existing technologies.

[0032] Explanation of main component symbols

[0033] Replaceable cutting tool 2

[0034] Handle 10

[0035] Tool holder reference surface 12

[0036] Fastening mechanism 16

[0037] Fastening hole 17

[0038] Screw hole 18

[0039] Tool tip 20

[0040] Central axis 20a

[0041] 20P slot

[0042] Blade mount 21

[0043] Reference plane 22

[0044] Reference plane parallel to the tool holder reference plane (first reference plane) 22A

[0045] Reference plane perpendicular to the tool holder reference plane (second reference plane) 22B

[0046] The reference plane parallel to the tool holder reference plane (third reference plane) 22C

[0047] Fastening mechanism 26

[0048] Cutting insert 30

[0049] Cutting edge 31

[0050] The cutting edge (the predetermined position of the cutting edge) 31t

[0051] 32 rake face

[0052] 35° peripheral side surface

[0053] Intersecting edges (edges) 36

[0054] upper surface 37

[0055] Corner 38

[0056] Blade retaining screw 39

[0057] Fastening screw 40

[0058] Flat surface 60

[0059] Scale 70

[0060] Width direction X

[0061] height direction Y Detailed Implementation

[0062] The preferred embodiments of the tool head provided by the present invention will now be described in detail with reference to the accompanying drawings (see attached figures). Figure 1 (etc.). The tool tip 20 can be fastened to the tool holder 10 of a cutting tool mounted on a machine tool (not shown), forming a reference surface 22 in a predetermined position.

[0063] A machine tool is a cutting device used to perform machining operations such as boring, external turning, and end-face machining on a workpiece. In this embodiment, the machine tool is equipped with a tool-changeable cutting tool 2 (see reference 10), consisting of a tool holder 10, a tool head 20, and cutting inserts 30. Figure 1 , Figure 6 wait).

[0064] The tool holder 10 includes a tool holder reference surface 12, a fastening mechanism 16, a screw hole 18, etc. In this embodiment, the tool holder 10 is approximately cylindrical and is also referred to as a round tool holder (see reference). Figure 1 (etc.). The tool holder reference surface 12 is a plane formed by removing a portion of the outer peripheral surface of the tool holder 10 (see reference). Figure 1 (etc.). The tool holder reference surface 12 serves as a positioning reference when mounting the tool holder 10 of the tool head changeable cutting tool 2 onto the machine tool. The front end of the tool holder 10 is provided with a fastening mechanism 16 for fastening the tool head 20 (see reference). Figure 1 (etc.). The fastening mechanism 16 consists of a fastening hole 17, a screw hole 18, and a fastening screw 40. The fastening hole 17 is provided at the front end of the tool holder 10 as a hole for mounting and dismounting the tool tip 20. The screw hole 18 is provided on the outer surface of the tool holder 10 as a hole for screwing in the fastening screw 40. The screw hole 18 may also be provided on the aforementioned tool holder reference surface 12 (see reference). Figure 1 wait).

[0065] The tool head 20 is a component that holds the cutting insert 30 while being fastened to the tool holder 10. In this embodiment, the tool head 20 is detachably mounted on the tool holder 10 with its central axis 20a aligned with the central axis of the tool holder 10. The tool head 20 includes an insert mounting base 21, a reference surface 22, a fastening mechanism 26, etc., and is generally approximately cylindrical (see reference). Figure 1 wait).

[0066] The cutting insert 30 is detachably mounted on the insert mount 21 (see reference). Figure 3A (etc.). The cutting insert 30 is mounted on the insert mounting base 21 with its rake face 32 facing a predetermined direction using the insert retaining screw 39 (see reference). Figure 1 , Figure 3A wait).

[0067] The cutting insert 30 performs various cutting operations on the workpiece, such as boring. In this embodiment, the cutting insert 30 has a cutting edge 31 (see reference) formed on the intersecting edge (edge ​​portion) 36 between its outer peripheral surface 35 and upper surface 37. This cutting edge 31 consists of a main cutting edge and a corner cutting edge. Figure 4 (etc.). The corner cutting edge is formed at the corner 38, and the main cutting edge is formed to be connected to the corner cutting edge (refer to...). Figure 2B , Figure 4 wait).

[0068] The reference surface 22 is formed as a reference portion for measuring the length of the cutting edge 31 of the cutting insert 30 mounted on the insert mount 21 of the tool head 20 from a predetermined position. With the tool head 20 removed from the tool holder 10 (i.e., the tool head alone), this reference surface 22 can measure various predetermined dimensions from the reference surface 22 to the cutting edge 31t of the cutting edge 31 (see reference). Figure 4 , 5 (etc.). The specific position of the cutting edge 31t of the cutting edge 31 described here can vary depending on the object being measured and the condition. This will be discussed in detail later.

[0069] On the tool tip 20, one or more reference surfaces 22 may be formed. Regardless of whether one or more are formed, it is preferable that the reference surfaces 22 of the tool tip 20 are parallel or perpendicular to the tool holder reference surface 12. In this embodiment, the tool tip 20 has three reference surfaces, namely the first reference surface 22A, the second reference surface 22B, and the third reference surface 22C. When viewed from the front (or rear) end along the central axis 20a of the tool tip 20, there are three straight sections on the outline of the tool tip 20. The two ends of these straight sections are connected to arcs on the outline, making the tool tip 20 approximately cylindrical (see reference). Figure 3A , 3B wait).

[0070] The first reference surface 22A is a reference surface formed in the tool head 20 that forms the back side portion of the blade mounting seat 21 (see reference). Figure 3A (etc.). The first reference surface 22A is formed parallel to the tool holder reference surface 12 when the tool tip 20 is mounted on the tool holder 10. Furthermore, for ease of representation in this specification, the direction perpendicular to the first reference surface 22A will be referred to as (etc.). Figure 3A , 3B The vertical direction in the diagram is called the "height direction" and is represented by the symbol Y. The direction parallel to the first reference plane 22A ( Figure 3A , 3B The left-right direction in the diagram is called the "width direction" and is represented by the symbol X. Using the first reference surface 22A as described above, the length (height) of the distance from the cutting edge 31 of the cutting insert 30 to a predetermined position (e.g., the cutting edge 31t) in the height direction Y (which is slightly inclined relative to the direction viewed towards the rake face 32 of the cutting insert 30) can be measured. Specifically, by placing the tool head 20 on the flat surface 60 with the first reference surface 22A facing down, and placing the scale (height gauge) 70 close to the predetermined position (e.g., the cutting edge 31t) from above, the length (height) from the first reference surface 22A to the predetermined position (the cutting edge 31t in this embodiment) can be measured (see reference 22A). Figure 5 ).

[0071] A typical example of the predetermined position described herein is the cutting edge 31t of the cutting edge 31 (more specifically, the cutting edge of the corner cutting edge 38 in the corner portion of the cutting edge 31). This is only one example of the predetermined position of the cutting edge 31, and other positions of the cutting edge 31 can also be used as measurement positions.

[0072] Relative to the central axis 20a of the tool head 20, the second reference surface 22B is formed at the front end of the extension of the virtual line connecting the predetermined position (e.g., cutting edge 31t) of the cutting edge 31 of the cutting insert 30 to the central axis 20a. In other words, it is formed on the side opposite to the cutting insert 30 and the insert mount 21 in the width direction X (see reference). Figure 3A The second reference surface 22B is formed perpendicular to the tool holder reference surface 12 and the first reference surface 22A. Using this second reference surface 22B, the length in the width direction X from a predetermined position (e.g., cutting edge 31t) of the cutting edge 31 of the cutting insert 30 can be measured. Specifically, by placing the tool head 20 on a flat surface 60 with the second reference surface 22B facing downwards, and placing a scale (height gauge) 70 tightly against the predetermined position (e.g., cutting edge 31t) from above, the length in the width direction X from the second reference surface 22B to the predetermined position (cutting edge 31t in this embodiment) can be measured (see reference). Figure 4 ).

[0073] The central axis 20a is located between the third reference plane 22C and the first reference plane 22A, and the third reference plane 22C is formed on the opposite side of the first reference plane 22A (see reference). Figure 2A (etc.). The third reference plane 22C is formed to be parallel to the first reference plane 22A and the tool holder reference plane 12 (see reference). Figure 3A (etc.). Such a third reference surface 22C can, for example, be used as the zero-point adjustment surface of the scale 70. That is, when using the scale 70 to measure the length (height) of the first reference surface 22A from a predetermined position (the cutting edge 31t in this embodiment), the zero point of the scale 70 can be pre-adjusted using the third reference surface 22C. Alternatively, when it is desired to compare the cutting edge position of the cutting insert 30 before and after use, the third reference surface 22C can be used as a reference surface that does not change before and after use.

[0074] The fastening mechanism 26 is used to fasten the tool tip 20 to the fastening mechanism 16 of the tool holder 10. The structure of the fastening mechanism 26 in this embodiment is the same as that of the fastening mechanism in the prior art, and it has a stepped cylindrical protrusion that can be attached to and detached from the fastening hole 17 of the tool holder 10 (see reference). Figure 2A (etc.). When viewed along the central axis 20a of the tool head 20 from the front end side with the blade holder, the size of the fastening mechanism 26 is such that it is not located outside the reference surfaces 22 (first reference surface 22A, second reference surface 22B, and third reference surface 22C); in other words, the size of the fastening mechanism 26 is contained within the contour of the tool head 20 (see reference). Figure 2C , Figure 3B Therefore, when the tool tip 20 is placed on the flat surface 60 with the first reference surface 22A or the second reference surface 22B facing downwards, the situation where the fastening mechanism 26 abuts against the flat surface 60 and makes measurement difficult will not occur (see reference). Figure 4 , Figure 5 wait).

[0075] The tool head 20 includes a reference surface 22 formed by a first reference surface 22A, a second reference surface 22B, and / or a third reference surface 22C. As described above, with such a tool head 20, measurements can be performed outside the machine tool using only the tool head. That is, historically, especially with boring tools, or external turning tools that can be used as boring tools, if the tool head is approximately cylindrical, it has been very difficult to measure the cutting edge position outside the machine tool using only the tool head. Therefore, with a reference surface provided on the tool holder 10, the cutting edge position can only be measured when the tool head 20 is mounted on another tool holder 10'. To address this, the tool head 20 provided in this embodiment, by providing a reference surface that was previously only provided on the tool holder on the tool head itself, allows for the measurement of the cutting edge position change that occurs when changing the cutting insert 30 outside the machine tool using only the tool head itself (see reference). Figure 6 Therefore, when using the tool head 20 described in this embodiment to perform external machine tool measurements each time the cutting insert 30 is replaced, it is not necessary to install the tool head 20 on other tool holders 10' and remove it from other tool holders 10', and even the other tool holders 10' used for external machine tool measurements are no longer needed.

[0076] Furthermore, when the reference surface 22 is formed on the tool head 20 itself, the impact on cutting performance can be minimized by using the tool head 20 with the above-described structure. That is, in the prior art structure, for example, a reference surface is formed by cutting off a portion of the outer surface of the round tool holder. Cutting off a portion reduces the volume of the round tool holder, which in turn has a significant impact on its rigidity, deflection, and even cutting performance. In this embodiment, the tool head 20 is fastened to the fastening hole 17 at the front end of the tool holder 10 by fastening mechanisms 16 and 26. Even if a portion of the tool head 20 is cut off to form the reference surface 22, the impact on the rigidity of the fastening mechanisms 16 and 26 is minimal. Therefore, the operation of cutting off a portion of the tool head 20 itself has a minimal impact on the overall rigidity of the component and on cutting performance. In other words, when the cutting head and shank are integrated, the cross-sectional area is directly related to rigidity. In the case of a replaceable cutting head, rigidity is almost entirely determined by the fastening mechanism 26 of the cutting head 20. Even if the cross-sectional area of ​​the cutting head 20 is increased unnecessarily, the rigidity of the fastening mechanism will not increase. Conversely, as long as it does not reduce the rigidity of the fastening mechanism 26, even if the cross-sectional area of ​​the cutting head 20 is reduced, the impact is very small. In this embodiment, from the perspective of improving chip removal capacity and weight reduction, by fully utilizing the above-mentioned structural characteristics, the portion around the insert mounting base 21 called the groove (…) can be further planed… Figure 2A (Used as 20P in the diagram) to form a deeper shape.

[0077] Furthermore, in this embodiment, the first reference surface 22A, the second reference surface 22B, and the third reference surface 22C, which are formed by cutting off a portion, have been illustrated, but these are only preferred examples of the reference surface 22. In addition, for example, the reference surface 22 can be formed as a curved surface, etc. In short, the reference surface 22 only needs to include three tangent points that uniquely define the posture (position, tilt, etc.) of the tool tip 20. As long as these three tangent points are included, a predetermined reference surface 22 can be defined by one tangent point and one tangent line. For example, the reference surface 22 can be defined using the two side edges of a curved concave surface.

[0078] Furthermore, in this embodiment, the positions, shapes, and sizes of the first reference surface 22A, the second reference surface 22B, and the third reference surface 22C are configured to allow the tool tip 20 to stand upright on the flat surface 60 (see reference). Figure 3A These are merely preferred examples of the reference surface 22. For instance, when the tool head 20 is placed on the flat surface 60 with the reference surface 22 facing downwards, even if the tool head 20 cannot be erected, it can be fixed with a clamp or held by hand while performing external measurements, but this only adds the inconvenience of holding it by hand. Furthermore, whether the tool head 20 can be erected depends on whether the torque calculated based on the shape of the tool head 20 (especially the cross-sectional shape), the position of the center of gravity in that shape, and the position and length of the reference surface 22 relative to the center of gravity is balanced.

[0079] Furthermore, the above embodiment is an example of a preferred embodiment of the present invention, and the present invention is not limited thereto. Various modifications can be made as long as they do not depart from the spirit and scope of the present invention. For example, in the above embodiment, the length of the distance from the predetermined position of the cutting edge 31 is taken as the object of measurement outside the machine tool. In this example, the cutting edge 31t of the cutting edge 31 is described, but it is only an example. That is to say, a typical example of the predetermined position mentioned here is the cutting edge 31t of the cutting edge 31 (more specifically, the cutting edge of the corner cutting edge in the corner portion 38 of the cutting edge 31). It is only an example of the predetermined position of the cutting edge 31, and other positions of the cutting edge 31 can also be used as measurement positions. For example, the measurement position can be the front end (corner portion 38) in the top view, or a part of the cutting edge 31 (the intersection line 36 of the rake face 32 and the flank face) on any cross section perpendicular to the central axis 20a.

[0080] Furthermore, the aforementioned tool head 20 can also be applied to rotary cutting tools, etc., that have a cutting edge (e.g., a single-edged edge) in one direction.

[0081] Industrial availability

[0082] This invention is preferably applied to the tool head of a replaceable cutting tool.

Claims

1. A tool head, which is an approximately cylindrical tool head for a tool head replacement type cutting tool, wherein a cutting insert is detachably mounted on an insert mount of the tool head, and the tool head is securely fastened to the tool holder along the central axis of the tool holder, the tool holder being held on a machine tool, wherein, On the outer periphery of the tool head in a direction perpendicular to the central axis of the tool head, the tool head has three points, or one point and a line, or a plane that define a reference surface, the reference surface being a predetermined length from a predetermined position of the cutting edge of the cutting insert; A tool holder reference surface is formed on the periphery of the tool holder by cutting off a portion of the periphery of the tool holder, and the reference surface of the tool tip is formed to be parallel or perpendicular to the tool holder reference surface; The reference surface is formed on the back side of the blade mounting portion in the tool head; and / or, the reference surface is formed on the side opposite to the predetermined position of the cutting edge relative to the central axis of the tool head.

2. The tool bit of claim 1 wherein, As the reference surface, a first reference surface is formed on the back side of the blade mounting seat in the tool head, and a second reference surface is formed on the side opposite to the predetermined position of the cutting edge relative to the central axis of the tool head.

3. The tool bit of claim 2 wherein, The central axis is located between the first reference plane and the third reference plane, and the third reference plane, which is parallel to the first reference plane, is formed on the opposite side of the first reference plane.

4. The tool bit of claim 1 wherein, The predetermined position is the cutting edge of the cutting edge.

5. The tool bit of claim 1 wherein, The tool head also includes a fastening mechanism for securing to the shank, the size of which, when viewed along the central axis of the tool head from the front end side having the blade mount, is such that it is not located outside the reference plane.

6. The tool tip according to claim 1, wherein, The reference plane is formed as a plane.

7. The tool tip according to claim 1, wherein, The reference surface is formed to allow the tool tip to stand upright on a flat placement surface.

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