Cutting tool

Abstract

Provided is a cutting tool that can easily form a flow path leading to a cutting edge. The cutting tool (10) includes a gripped portion (100) and a cutting portion (200). A flow path is formed inside the gripped portion (100) and the cutting portion (200), and this flow path is for guiding a fluid supplied from the outside to a flow outlet (221). The above-mentioned flow path includes: a first flow path (310) that extends in a straight line parallel to the rotation center axis (AX) from an end portion of the gripped portion (100) on the side opposite to the cutting portion (200); a second flow path (320) that extends in a straight line from the first flow path (310) toward the cutting edge of the cutting blade (30). The first flow path (310) is formed at an eccentric position such that its central axis does not coincide with the rotation center axis (AX).

Description

Technical Field

[0001] The present invention relates to a cutting tool. Background Art

[0002] Cutting tools for machining metals and the like include: a gripped portion that is gripped by a machine tool such as a milling machine; and a cutting portion that is provided with a cutting edge. While gripping the gripped portion, the machine tool rotates the entire cutting tool and presses the cutting edge of the cutting portion against a workpiece such as metal to machine the workpiece.

[0003] At this time, a fluid is generally supplied to the point (cutting point) where the cutting edge contacts the workpiece or its vicinity. The purpose of supplying such a fluid is, for example, to discharge chips, cool the cutting tool, cool and lubricate the workpiece, and prevent rust. It should be noted that the fluid is mostly a liquid, and sometimes a gas is also used. The fluid is sometimes supplied by an external nozzle provided around the cutting tool, but as described in Patent Document 1 below, it is sometimes supplied through a flow path formed inside the cutting tool.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2016-68172 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] The fluid is supplied to the cutting tool by the machine tool from the surface on the rear end side in the gripped portion. Therefore, the flow path formed inside the cutting tool can be considered to be separately formed with: a first flow path that linearly extends from the rear end face along the rotation center axis; and a plurality of second flow paths that linearly extend from the first flow path to the cutting edge on the outer peripheral side.

[0009] However, in such a structure, it becomes difficult for the fluid passing through the linearly extending second flow path to directly contact the cutting edge located inside the chip groove. Therefore, in the cutting tool described in Patent Document 1 above, the flow path for guiding the fluid from the central first flow path to the cutting edge on the outer peripheral side is formed as a flow path (second flow path and third flow path) that bends midway, so that the fluid directly contacts the cutting edge.

[0010] However, in such a structure, since the process for forming the bent flow path is complicated, the manufacturing cost may increase.

[0011] An object of the present invention is to provide a cutting tool in which a flow path leading to the cutting edge can be easily formed.

[0012] Technical solution for solving the problem

[0013] A cutting tool according to an aspect of the present invention includes: a gripped portion which is a cylindrical portion gripped by a machine tool and whose central axis coincides with the rotation center axis; a cutting portion on which a concave chip groove is formed; and a plurality of cutting edges arranged circumferentially on the inner surface of the chip groove. A flow path is formed inside the gripped portion and the cutting portion, and this flow path is used to guide the fluid supplied from the outside to an outlet formed around the cutting edge. The flow path includes: a first flow path which extends linearly parallel to the rotation center axis from the end portion of the gripped portion on the side opposite to the cutting portion; and a second flow path which extends linearly from the first flow path toward the cutting edge, and the first flow path is formed at an eccentric position such that its central axis does not coincide with the rotation center axis.

[0014] In the cutting tool having the above structure, since the first flow path is formed at an eccentric position in a manner that does not coincide with the rotation center axis, even if the entire second flow path on the downstream side of the first flow path is a linear flow path, the fluid passing through the second flow path can flow toward the cutting edge. Moreover, since it is not necessary to bend the second flow path midway, a flow path leading to the cutting edge can be easily formed.

[0015] As a more preferable aspect, a plurality of first flow paths can be formed.

[0016] As a more preferable aspect, the number of the first flow paths can be less than the number of the cutting edges arranged circumferentially.

[0017] As a more preferable aspect, one first flow path can be connected to a plurality of second flow paths so that the fluid passing through one first flow path is supplied to a plurality of cutting edges respectively.

[0018] As a more preferable aspect, at the end portion of the gripped portion on the side opposite to the cutting portion, a single concave portion is formed in a manner of retreating toward the cutting portion side, and an inlet for the fluid flowing into the first flow path can be formed at a position where at least a part of it coincides with the concave portion.

[0019] As a more preferable aspect, the concave portion can be formed within the range including the rotation center axis.

[0020] As a more preferable aspect, in the cutting portion, a plurality of cutting edges arranged circumferentially can be provided at a plurality of step positions arranged in the direction along the rotation center axis respectively.

[0021] As a more preferable aspect, one first flow path can be connected to a plurality of second flow paths so that the fluid passing through one first flow path is supplied to each of the cutting edges located at a plurality of step positions.

[0022] As a more preferred aspect, the cutting edge may be a part of a cutting blade mounted on the inner surface of the chip groove.

[0023] As a more preferred aspect, the outlet port, which is the outlet of the fluid passing through the second flow path, is formed on the inner surface of the chip groove, and the position of the outlet port in the direction of the rotation center axis may be a position that coincides with the range where the cutting blade is provided in the same direction.

[0024] Advantages of the Invention

[0025] According to the present invention, there is provided a cutting tool capable of easily forming a flow path leading to the cutting edge. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 FIG. is a perspective view showing the structure of the cutting tool of the first embodiment;

[0027] Figure 2 FIG. is a view depicting the cutting tool of the first embodiment as observed from the front end side;

[0028] Figure 3 FIG. is a view depicting the cutting tool of the first embodiment as observed from the side;

[0029] Figure 4 FIG. is a perspective view showing the structure of the cutting tool of the first embodiment;

[0030] Figure 5 FIG. is a view showing the flow path formed in the cutting tool of the first embodiment;

[0031] Figure 6 FIG. is a view showing the flow path formed in the cutting tool of the first embodiment;

[0032] Figure 7 FIG. is a view showing the structure of the cutting tool of the first embodiment;

[0033] Figure 8 FIG. is a view showing the structure of the cutting tool of the comparative example;

[0034] Figure 9 FIG. is a view showing the structure of the cutting tool of the comparative example;

[0035] Figure 10 FIG. is a view showing the structure of the cutting tool of the comparative example;

[0036] Figure 11 FIG. is a view showing the structure of the cutting tool of the first embodiment;

[0037] Figure 12 FIG. is a view for explaining the positional relationship between the outlet port and the cutting blade of the cutting tool of the first embodiment;

[0038] Figure 13 This is a view showing the structure of the cutting tool according to the second embodiment.

[0039] Explanation of reference numerals

[0040] 10: Cutting tool;

[0041] 30: Cutting insert;

[0042] 100: Held portion;

[0043] 200: Cutting portion;

[0044] 210: Chip groove;

[0045] 310: First flow path;

[0046] 320: Second flow path;

[0047] AX: Rotation center axis. Detailed description of the embodiment

[0048] Hereinafter, this embodiment will be described with reference to the accompanying drawings. For ease of understanding, in each of the drawings, the same reference numerals are given to the same components as much as possible, and repeated descriptions are omitted.

[0049] The structure of the cutting tool 10 according to the first embodiment will be described. The cutting tool 10 according to this embodiment is used by being mounted on a machine tool (not shown) such as a milling machine, and is configured as a roughing end mill. As Figure 1 shown, the cutting tool 10 includes a held portion 100 and a cutting portion 200.

[0050] The held portion 100 is a portion that can also be referred to as a "shank", and is a cylindrical portion that is held by a machine tool (not shown). The central axis of the held portion 100 coincides with the rotation center axis AX when the cutting tool 10 rotates. The held portion 100 is a portion on one side of the cutting tool 10 along the rotation center axis AX ( Figure 1 the right side portion in ). In addition, the cutting portion 200 described below is a portion on the other side of the cutting tool 10 along the rotation center axis AX ( Figure 1 the left side portion in ). Hereinafter, the direction along the rotation center axis AX toward the held portion 100 will be referred to as the "rear end side". In addition, hereinafter, the direction along the rotation center axis AX toward the cutting portion 200 will be referred to as the "front end side".

[0051] The cutting part 200 is the part where a plurality of cutting blades 30 are installed, and it is the part that processes the material to be cut by the cutting blades 30. The cutting blade 30 is a replaceable cutting edge fastened to the cutting part 200. The edge part formed at the front end of the cutting blade 30 is used as the "cutting edge" for cutting the material to be cut. It should be noted that as shown in this embodiment, the edge part that becomes the cutting edge in the cutting blade 30 can be the front end of the cutting blade 30, or the entire edge of the cutting blade 30 (that is, the range covering the entire circumference of the polygon). There is no particular limitation on which part of the cutting blade 30 is used as the cutting edge.

[0052] A concave chip groove 210 is formed in the cutting part 200. The chip groove 210 is formed as a space for receiving the chips generated during cutting and discharging the chips to the outside. A plurality of concave blade seats (not shown) are arranged along the circumferential direction on the inner surface of the chip groove 210, and the cutting blades 30 are fastened to each blade seat. As a result, the cutting edges of a plurality of cutting blades 30 are arranged along the circumferential direction.

[0053] In this embodiment, the chip groove 210 is formed according to the number of each cutting blade 30. That is, similar to the cutting blade 30, a plurality of chip grooves 210 are also arranged along the circumferential direction. Among them, the chip groove 210 provided with one cutting blade 30 and the chip groove 210 provided with another cutting blade 30 can be connected to each other.

[0054] Figure 2 The appearance of the cutting part 200 when viewed from the front end side along the rotation center axis AX is shown. As shown in this figure, five chip grooves 210 arranged at equal intervals along the circumferential direction are formed on the front end side of the cutting part 200, and a cutting blade 30 is fixed on the inner surface of each chip groove 210. The arrow shown in this figure indicates the rotation direction of the cutting tool 10 during use. The cutting blade 30 is fixed on the surface of the end part on the rearmost side in the rotation direction in the inner surface of the chip groove 210.

[0055] The chip groove 210 and the cutting blade 30 are not only provided on the front end side of the cutting part 200, but also a plurality of them are provided on the side part of the cutting part 200. The specific configuration will be described in combination with Figure 3 for explanation. Figure 3 The appearance of the cutting tool 10 when viewed from a direction perpendicular to the rotation center axis AX is shown. As shown in this figure, in the cutting part 200, a plurality of chip grooves 210 arranged along the circumferential direction are respectively formed at a plurality of step positions arranged along the direction of the rotation center axis AX, and a cutting blade 30 is fixed in each chip groove 210. The number of chip grooves 210 formed at each step position can be different from the number of cutting blades 30 at that step position.

[0056] Hereinafter, at a step position, the number of a plurality of cutting blades 30 arranged circumferentially (5 in this embodiment) is referred to as the "number of cutting edges". The total number of the cutting blades 30 provided in the cutting portion 200 is the step position × the number of cutting edges. It should be noted that the number of cutting edges may be different at each step position.

[0057] Figure 3 Among them, the cutting blades 30 marked with the reference numeral "31" are 5 cutting blades 30 arranged circumferentially at the step position on the foremost end side. The cutting blades 30 marked with the reference numeral "32" are 5 cutting blades 30 arranged circumferentially at the second step position starting from the front end side. The cutting blades 30 marked with the reference numeral "33" are 5 cutting blades 30 arranged circumferentially at the third step position starting from the front end side. The cutting blades 30 marked with the reference numeral "34" are 5 cutting blades 30 arranged circumferentially at the fourth step position starting from the front end side, that is, the step position on the rearmost end side. Hereinafter, the cutting blades 30 located at each step position are referred to as "cutting blade 31" or "cutting blade 32".

[0058] In addition, hereinafter, the step position on the foremost end side is referred to as the "first step", and hereinafter, the second step position starting from the front end side is referred to as the "second step". Similarly, hereinafter, the third step position starting from the front end side is referred to as the "third step", and hereinafter, the fourth step position starting from the front end side is referred to as the "fourth step".

[0059] As Figure 1 and Figure 3 shown, etc., an outflow port 221 is formed at a position on the inner surface of each chip groove 210 that is around the cutting blade 30. The outflow port 221 is an opening provided for supplying fluid to the cutting blade 30. As will be described later, a flow path for guiding the fluid supplied from the outside to the outflow port 221 is formed inside the cutting tool 10, and the outflow port 221 is the end portion on the most downstream side of this flow path.

[0060] It should be noted that the above-mentioned "fluid" is a fluid supplied from the outside for discharging chips, cooling the cutting tool, and cooling, lubricating the material to be cut, and preventing rust, etc., such as a fluid called "coolant" or "lubricant", etc. The purpose of supplying the fluid is not particularly limited. In addition, the fluid may be a liquid or a gas.

[0061] As Figure 4As shown, three inlets 121 are formed at the end of the gripped portion 100 on the side opposite to the cutting portion 200, i.e., the end on the rearmost side. The inlet 121 is an opening provided as an inlet for the above-mentioned fluid supplied from the outside. That is, each inlet 121 is the end on the most upstream side of the above-mentioned flow path. The fluid flows into the flow path inside the cutting tool 10 through the inlet 121, and after passing through this flow path, it is discharged from the aforementioned outlet 221 and supplied to the cutting edges of the respective cutting inserts 30.

[0062] The specific shape of the above-mentioned flow path formed inside the cutting tool 10 will be described. Figure 5 For observing the shape of the flow path formed inside the cutting tool 10 from the Figure 3 same perspective, a diagram is depicted. Figure 6 For observing the shape of the flow path formed inside the cutting tool 10 from the Figure 2 same perspective, a diagram is depicted. As Figure 5 and Figure 6 shown, the above-mentioned flow path includes a first flow path 310 and a second flow path 320.

[0063] The first flow path 310 is formed in a straight line extending parallel to the rotation center axis AX from the rear end portion of the gripped portion 100 on the side opposite to the cutting portion 200. The opening formed at the end on the most upstream side in the first flow path 310 is the Figure 4 shown inlet 121. The first flow path 310 penetrates the entire gripped portion 100 along the rotation center axis AX from the inlet 121 and further extends to a position in the middle of the cutting portion 200.

[0064] As Figure 6 shown, three first flow paths 310 are formed. Each first flow path 310 is formed at an eccentric position such that its central axis does not coincide with the rotation center axis AX, and is formed in such a way as to surround the periphery of the rotation center axis AX at the same angular interval. That is, in the present embodiment, the three first flow paths 310 are provided at different positions at intervals of 120 degrees in the circumferential direction.

[0065] The second flow path 320 extends linearly from a position in the middle of the first flow path 310 toward each cutting insert 30. The end on the downstream side of each second flow path 320 is the aforementioned outlet 221, which is an opening formed on the inner surface of each chip groove 210. One or two outlets 221 are formed on the inner surface of each chip groove 210, and the second flow path 320 is formed to extend from each outlet 221 toward any one of the first flow paths 310.

[0066] In the present embodiment, both the first flow path 310 and the second flow path 320 are formed as linear flow paths having a circular cross-section. Therefore, each flow path can be easily formed by drilling. The inner diameter of the second flow path 320 is smaller than the inner diameter of the first flow path 310.

[0067] In Figure 5 , the second flow path 320 marked with the reference numeral "321" is the second flow path 320 formed so as to extend toward the cutting blade 31 of the first step. In Figure 5 , the second flow path 320 marked with the reference numeral "322" is the second flow path 320 formed so as to extend toward the cutting blade 32 of the second step. In Figure 5 , the second flow path 320 marked with the reference numeral "323" is the second flow path 320 formed so as to extend toward the cutting blade 33 of the third step. In Figure 5 , the second flow path 320 marked with the reference numeral "324" is the second flow path 320 formed so as to extend toward the cutting blade 34 of the fourth step. These flow paths are all connected to the common first flow path 310 (the first flow path 310 marked with the reference numeral "311" in Figure 5 ). The other first flow paths 310 are the same as above and are connected to the respective second flow paths 320 leading to the cutting blades 30 located at each step position.

[0068] Thus, in the cutting tool 10 of the present embodiment, a plurality of second flow paths 320 are connected to one first flow path 310 so that the fluid passing through one first flow path 310 is supplied to the respective cutting blades 30 located at a plurality of step positions. In such a structure, since there is no need to increase the number of first flow paths 310 according to the number of step positions, the inner diameter of the first flow path 310 can be sufficiently ensured, and the flow path resistance in the first flow path 310 can be reduced.

[0069] It should be noted that the cutting tool 10 of the present embodiment is configured such that two second flow paths 320 lead to the cutting blades 31 of each first step, and is also configured such that one second flow path 320 leads to the respective cutting blades 32 after the second step, etc. The reason for increasing the number of second flow paths 320 leading to the cutting blades 31 of the first step is that the machining load borne by the cutting blades 31 of the first step is greater than the machining load borne by the other cutting blades 32, etc. The number of second flow paths 320 leading to the cutting blades 30 at each step position can be appropriately changed.

[0070] Figure 7 Same as Figure 2 , it is also a view drawn by observing the cutting portion 200 from the front end side along the rotation center axis AX. Figure 7The first flow path 310 and the second flow path 320 leading to the cutting blade 31 of the first step are depicted. The illustration of the other second flow paths 320 is omitted. In addition, Figure 7 A simplified view schematically depicting a part of the inner surface of the chip groove 210 is shown. As Figure 7 shown, focusing on the five cutting blades 31 located at the step position on the foremost end side, second flow paths 320 are respectively formed to supply fluid from one first flow path 310 to one or two cutting blades 31. That is, a plurality of second flow paths 320 are connected to one first flow path 310 so that the fluid passing through one first flow path 310 is supplied to the plurality of cutting blades 31 respectively.

[0071] Therefore, at the same step position, the number of the first flow paths 310 (3) is less than the number of the cutting blades 31 arranged circumferentially, that is, the number of cutting edges (5), but fluid can be supplied to all the cutting blades 31. The structures of the cutting blades 32 etc. located at other step positions are also the same.

[0072] In such a structure, compared with the case where the number of the first flow paths 310 is the same as the number of the cutting blades 31, since the inner diameter of the first flow path 310 can be increased, the flow path resistance in the first flow path 310 can be reduced.

[0073] As described above, each first flow path 310 is formed at an eccentric position such that its central axis does not coincide with the rotation center axis AX, and is formed so as to surround the periphery of the rotation center axis AX at the same angular interval. To explain the advantages of such a structure, the structure of the cutting tool 10A of the comparative example will be described below. Figure 8 In, the appearance of the cutting tool 10A is depicted from the Figure 3 same perspective. Figure 9 In, the appearance of the cutting tool 10A is depicted from the Figure 2 same perspective.

[0074] The cutting tool 10A is configured as a precision machining end mill having cutting blades 30 only on the first step on the front end side. In this comparative example, a first flow path 310 and a second flow path 320 are also formed inside the cutting tool 10A.

[0075] However, the first flow path 310 in this comparative example is not formed at an eccentric position as in the present embodiment, but is formed at a position where its central axis coincides with the rotation center axis AX, that is, at a position passing through the center of the gripped portion 100. As Figure 9 shown, each second flow path 320 is formed to extend linearly from the first flow path 310 located at the center to the outside chip groove 210.

[0076] In such a structure, if the fluid outlet 221 is provided near the cutting blade 30 (for example, at a position circumferentially adjacent to the cutting blade 30), the direction in which the fluid is discharged from the second flow path 320 is a direction deviating from the cutting blade 30. Since the fluid discharged from the second flow path 320 does not directly contact the vicinity of the cutting edge of the cutting blade 30, in particular, problems such as the function of the fluid not being fully exerted and the life of the cutting blade 30 being reduced will occur.

[0077] To solve such problems, for example, as Figure 10 shown in the example, the second flow path 320 is bent in the middle, and the downstream portion is formed to face the cutting blade 30. However, in such a structure, the shape of the second flow path 320 is complex, and multiple drilling operations are required, which may result in an increase in manufacturing cost. In addition, in this case, since the opening is formed in a portion different from the inlet or outlet of the fluid, it is necessary to supplement the opening, thereby further increasing the manufacturing cost. Moreover, in a structure in which the second flow path 320 is bent significantly, there is also a problem of increased flow path resistance.

[0078] In contrast, in Figure 7 the cutting tool 10 of the present embodiment shown, each second flow path 320 is formed to extend toward the cutting blade 30, and a first flow path 310 is formed at the upstream end of the second flow path 320. As a result, each first flow path 310 is provided at an eccentric position deviated from the rotation center axis AX.

[0079] Figure 11 A part of the cross section when cutting the cutting portion 200 perpendicular to the rotation center axis AX is schematically depicted in Figure 11 The dashed line DL shown in

[0080] Figure 12 is drawn by extending the straight-line extension direction of the second flow path 320 outward, and shows the direction in which the fluid passing through the second flow path 320 is ejected from the fluid outlet 221. As shown in this figure, the second flow path 320 is preferably formed such that a part of the cutting blade 30 is located inside the range shown by the dashed line DL. In other words, the second flow path 320 is preferably formed such that at least a part of the ejected fluid directly contacts a part of the cutting blade 30. The above-mentioned "part of the cutting blade 30" is more preferably the cutting edge part of the cutting blade 30. Figure 3 is an enlarged view of the cutting portion 200 part in Figure 12 Here, the cutting blade 30 marked with the reference numeral "30" and the fluid outlet 221 marked with the reference numeral "221" in this figure are mainly described. These cutting blades 30 and fluid outlets 221 are provided in the same chip groove 210.

[0081] Figure 12 The shown range A1 represents the range where the cutting blade 30 is provided in the direction along the rotation center axis AX. Figure 12 The shown range A2 represents the range where the fluid outlet 221 is formed in the direction along the rotation center axis AX. In the present embodiment, the entire range A2 is included in the range A1. That is, the position of the fluid outlet 221 in the direction along the rotation center axis AX is the position that coincides with the range A1 where the cutting blade 30 is provided in the same direction.

[0082] Assume that the fluid outlet 221 is provided at a position more toward the rear end side than the range A1 where the cutting blade 30 is provided. Then, the fluid is ejected from the fluid outlet 221 in a state where the velocity component toward the front end side is large and is supplied to the cutting blade 30 on the front end side. In this case, since the flow direction of the fluid is opposite to the chip discharge direction, the discharge of the chips will be hindered by the fluid flow, and problems such as chip jamming may occur.

[0083] In contrast, in the present embodiment, as described above, since the fluid outlet 221 is provided at a position that coincides with the range A1, the fluid is ejected from the fluid outlet 221 in a state where the velocity component toward the front end side is small and is supplied to the cutting blade 30 on the front end side. Therefore, it is not easy for the discharge of the chips to be hindered by the fluid flow. It should be noted that, as described in the present embodiment, the fluid outlet 221 can be formed at a position entirely inside the range A1 or at a position where only a part of it is inside the range A1.

[0084] The positional relationship between all the other fluid outlets 221 and the cutting blade 30 is the same as the positional relationship between the fluid outlet 221 and the cutting blade 30 described above.

[0085] Hereinafter, other structures will be described. As Figure 4 shown, at the end portion on the rearmost side of the gripped portion 100, a single recess 110 is formed so as to retreat toward the cutting portion 200 side, and the aforementioned three fluid inlets 121 are formed inside the recess 110.

[0086] Most machine tools that can supply fluid to the internal flow path of the cutting tool are configured to supply fluid from the center of the cutting tool. Therefore, as described in the present embodiment, when the first flow path 310 is formed at an eccentric position deviating from the rotation center axis AX, since the position where the fluid is supplied by the machine tool and the position of the first flow path 310 do not match each other, it may cause the fluid to not flow smoothly into the fluid inlet 121.

[0087] Therefore, in the cutting tool 10 of the present embodiment, the recess 110 is provided as described above. In such a structure, the fluid supplied by the machine tool along the rotation center axis AX first flows into the inside of the recess 110, and then is smoothly distributed to the first flow path 310 through each inflow port 121. Therefore, the above problems caused by the formation of the first flow path 310 at an eccentric position will not occur.

[0088] The range where the recess 110 is formed only needs to be a range that at least includes the rotation center axis AX inside it. In addition, as described in the present embodiment, the inflow ports 121 may be formed entirely within the range that coincides with the recess 110, or only a part of them may be formed at positions that coincide with the recess 110. Moreover, there may also be inflow ports 121 that are entirely formed within the range that coincides with the recess 110 and inflow ports 121 where only a part of them is formed at positions that coincide with the recess 110.

[0089] The second embodiment will be described. Hereinafter, mainly the differences between the second embodiment and the first embodiment will be described, and the common points with the first embodiment will be appropriately omitted.

[0090] Figure 13 In, the appearance of the cutting tool 10 of the present embodiment is depicted from the same perspective. As Figure 3 shown, similar to the comparative example of Figure 13 , the cutting tool 10 of the present embodiment is configured as a precision end mill having a cutting blade 30 provided only on the first step on the front end side. Figure 8 Similar to the first embodiment, three first flow paths 310 are formed linearly in the present embodiment. Each first flow path 310 is formed at an eccentric position such that its central axis does not coincide with the rotation center axis AX. In addition, in the present embodiment, a second flow path 320 is linearly formed so as to extend from the first flow path 310 toward the cutting blade 30. The specific shapes and configurations of the first flow path 310 and the second flow path 320 are the same as the shapes and configurations shown in

[0091] . Thus, the structures such as the first flow path 310 described in the first embodiment can also be applied to various cutting tools other than the rough machining type, and the same effects as those of the first embodiment can be obtained. Figure 7 shown.

[0092] As described above, an example in which the cutting edge of the cutting tool 10 is provided on the cutting blade 30 and has a structure with a replaceable cutting edge has been described. However, for a cutting tool in which, for example, the cutting edge is brazed to the cutting tool 10 and has a structure with a non-replaceable cutting edge, the above-described flow path and other structures can also be applied.

[0093] As described above, the present embodiment has been described with reference to specific examples. However, the present disclosure is not limited to these specific examples. Appropriate design changes made by those skilled in the art to these specific examples are included in the scope of the present disclosure as long as they have the features of the present disclosure. The various elements, their configurations, conditions, shapes, etc. possessed by the foregoing specific examples are not limited to the above examples and can be appropriately changed. As long as there is no technical conflict among the various elements possessed by the foregoing specific examples, their combinations can be appropriately changed.

Claims

1. A cutting tool, characterized in that, Comprising: A gripped portion, which is a cylindrical portion gripped by a machine tool, and whose central axis coincides with the rotation center axis; A cutting portion, formed with a concave chip groove; And Cutting edges, which are arranged circumferentially on the inner surface of the chip groove, with a plurality of them; A flow path is formed inside the gripped portion and the cutting portion, and the flow path is used to guide the fluid supplied from the outside to the outlet formed around the cutting edges; The flow path includes: A first flow path, which extends linearly from the end of the gripped portion on the side opposite to the cutting portion, in a direction parallel to the rotation center axis; and A second flow path, which extends linearly from the first flow path towards the cutting edges; The first flow path is formed at an eccentric position in such a way that its central axis does not coincide with the rotation center axis, where A plurality of the first flow paths are formed, where The number of the first flow paths is less than the number of the cutting edges arranged circumferentially; and Wherein, a plurality of the second flow paths are connected to one of the first flow paths, so that the fluid passing through one of the first flow paths is supplied to the plurality of cutting edges respectively; Each of the plurality of the second flow paths is connected to a different position of one of the first flow paths.

2. The cutting tool according to claim 1, characterized in that, At the end of the gripped portion on the side opposite to the cutting portion, a single concave portion is formed in a manner of retreating towards the cutting portion side, An inlet is formed at a position where at least a part of it coincides with the concave portion as the inlet of the fluid flowing into the first flow path.

3. The cutting tool according to claim 2, characterized in that, The concave portion is formed within the range including the rotation center axis.

4. The cutting tool according to claim 1, characterized in that, In the cutting portion, A plurality of cutting edges arranged circumferentially are respectively provided at a plurality of stepped positions arranged in the direction of the rotation center axis.

5. The cutting tool according to claim 4, characterized in that, A plurality of the second flow paths are connected to one of the first flow paths, so that the fluid passing through one of the first flow paths is supplied to each of the cutting edges located at the plurality of stepped positions.

6. The cutting tool according to claim 1, characterized in that, The cutting edges are a part of the cutting inserts mounted on the inner surface of the chip groove.

7. The cutting tool according to claim 6, characterized in that, The outlet is formed on the inner surface of the chip groove as the outlet of the fluid passing through the second flow path, The position of the outlet in the direction of the rotation center axis is a position that coincides with the range where the cutting inserts are provided in the same direction.

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