Method for machining dovetail groove, machine tool, and tool bit

Abstract

This method for machining a dovetail groove comprises: a step for causing a tool bit to enter the dovetail groove in a rough machining state; a step for cutting a portion of the groove bottom of the dovetail groove by moving the tool bit along the extension direction of the dovetail groove in a state in which the tool bit has entered the dovetail groove; a step for changing the position of the tool bit in the width direction of the dovetail groove; and a step for cutting another portion of the groove bottom by moving the tool bit along the extension direction of the dovetail groove in a state in which the tool bit has entered the dovetail groove after the position of the tool bit in the width direction of the dovetail groove has been changed. The tool bit has a blade part in which the blade width increases from a root part toward a tip edge part. The dovetail groove has an opening width through which the tip edge part can pass.

Description

Dovetail groove machining method, machine tool, and tool bit

[0001] The present invention relates to a dovetail groove machining method, a machine tool, and a tool bit.

[0002] Techniques for forming dovetail grooves are known.

[0003] As a related technique, Patent Document 1 discloses a dovetail groove machining device. The dovetail groove machining device described in Patent Document 1 includes a cutter having a cutting edge surface provided on a conical surface. The cutter is fed in the forward direction, then fed in the left-right direction, and further fed in the rearward direction thereafter.

[0004] Japanese Unexamined Patent Publication No. 56-34407

[0005] An object of the present invention is to provide a dovetail groove machining method, a machine tool, and a tool bit capable of suitably cutting the groove bottom of a dovetail groove.

[0006] Embodiments of the present invention relate to the dovetail groove machining method, machine tool, and tool bit described below.

[0007] (1) A method for machining a dovetail groove, comprising the steps of: inserting a tool bit into a rough-machined dovetail groove; moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove to cut a portion of the groove bottom of the dovetail groove; changing the position of the tool bit in the width direction of the dovetail groove; and, after the position of the tool bit has been changed in the width direction of the dovetail groove, moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove to cut another portion of the groove bottom, wherein the tool bit has a cutting edge whose cutting width increases from the root to the tip edge, and the dovetail groove has an opening width through which the tip edge can pass. (2) A machine tool comprising: a machining head that holds a tool holder to which a tool bit having a cutting edge that widens from the base to the tip edge is attached; a work support device that supports a workpiece; a moving device that moves the machining head relative to the work support device; and a control device that controls the moving device, wherein the control device is capable of performing the following processes: inserting the tool bit into a rough-machined dovetail groove formed in the workpiece; cutting a portion of the groove bottom of the dovetail groove by moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove; changing the position of the tool bit in the width direction of the dovetail groove; and cutting another portion of the groove bottom by moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove after the position of the tool bit has been changed in the width direction of the dovetail groove. (3) A tool bit comprising a blade portion whose blade width increases from the base to the tip edge, and a shaft that supports the blade portion, wherein the tip edge of the blade portion has a plurality of apex portions that contact the bottom of the groove of the dovetail groove.

[0008] The present invention provides a method for machining dovetail grooves, a machine tool, and a tool bit that can suitably cut the groove bottom of the dovetail groove.

[0009] Figure 1 is a schematic perspective view illustrating an example of a workpiece. Figure 2 is a schematic cross-sectional view illustrating an example of a workpiece. Figure 3 is a schematic cross-sectional view illustrating the entry process. Figure 4 is a schematic cross-sectional view illustrating the entry process. Figure 5 is a schematic perspective view illustrating the machining of a portion of the groove bottom of a dovetail groove. Figure 6 is a schematic perspective view illustrating the machining of a portion of the groove bottom of a dovetail groove. Figure 7 is a schematic perspective view illustrating the machining of the outside region of the groove bottom of a dovetail groove. Figure 8 is a schematic cross-sectional view illustrating the change in the position of the tool bit in the width direction of the dovetail groove. Figure 9 is a schematic cross-sectional view illustrating the change in the position of the tool bit in the width direction of the dovetail groove. Figure 10 is a schematic perspective view illustrating the machining of another portion of the groove bottom of the dovetail groove after the position of the tool bit has been changed in the width direction of the dovetail groove. Figure 11 is a schematic front view illustrating an example of a tool bit. Figure 12 is an enlarged view of a portion of Figure 11. Figure 13 is a schematic plan view illustrating how multiple grooves are formed at the bottom of the groove along the direction of extension of the dovetail groove. Figure 14 is a schematic diagram illustrating how the tool bit is attached to the spindle via a tool holder. Figure 15 is a schematic perspective view illustrating another example of the workpiece. Figure 16 is a schematic front view illustrating the tool bit in the first modification. Figure 17 is a schematic front view illustrating the tool bit in the second modification. Figure 18 is a schematic front view illustrating the tool bit in the third modification. Figure 19 is a schematic perspective view of the tool bit viewed from diagonally below. Figure 20 is a schematic side view illustrating a part of the tool bit. Figure 21 is a schematic bottom view illustrating an example of the tool bit. Figure 22 is a schematic cross-sectional view illustrating the entry process. Figure 23 is a schematic perspective view illustrating the entry process. Figure 24 is a schematic perspective view illustrating how the orientation of the cutting edge of the tool bit is changed after the entry process is performed. Figure 25 is a schematic cross-sectional view illustrating how the position of the tool bit changes in the width direction of the dovetail groove. Figure 26 is a schematic cross-sectional view illustrating the state after the first machining cycle has been performed three times. Figure 27 is a schematic perspective view illustrating how the orientation of the cutting edge changes around the first axis.Figure 28 is a schematic perspective view illustrating the machining of the inside region at the bottom of a dovetail groove. Figure 29 is a schematic cross-sectional view illustrating the state after the second machining cycle has been performed twice. Figure 30 is a schematic cross-sectional view illustrating the placement of a seal ring in a dovetail groove. Figure 31 is a schematic cross-sectional view illustrating an example of a lid with a dovetail groove formed therein. Figure 32 is a schematic cross-sectional view illustrating an example of a rough machining process. Figure 33 is a schematic cross-sectional view illustrating another example of a rough machining process. Figure 34 is a flowchart illustrating an example of a dovetail groove machining method in the first embodiment. Figure 35 is a flowchart illustrating another example of a dovetail groove machining method in the first embodiment. Figure 36 is a schematic perspective view illustrating a machine tool in the second embodiment. Figure 37 is a schematic front view illustrating the execution of a tool change process. Figure 38 is a schematic diagram illustrating how a control device can control multiple controllable devices. Figure 39 is a schematic front view illustrating a part of a machine tool in the second embodiment. Figure 40 is a schematic front view illustrating a portion of the machine tool in the second embodiment. Figure 41 is a schematic front view illustrating a portion of the machine tool in the second embodiment.

[0010] The following description of the embodiment will explain the method for machining the dovetail groove, the machine tool 1, and the tool bit 8 with reference to the drawings. In the following description of the embodiment, parts and components having the same function will be denoted by the same reference numerals, and repeated explanations of parts and components denoted by the same reference numerals will be omitted.

[0011] (First Embodiment) A method for machining a dovetail groove in the first embodiment will be described with reference to Figures 1 to 35. Figure 1 is a schematic perspective view showing an example of a workpiece 9. Figure 2 is a schematic cross-sectional view showing an example of a workpiece 9. Figures 3 and 4 are schematic cross-sectional views showing the entry process. Figures 5 and 6 are schematic perspective views showing how a part of the groove bottom 91 of the dovetail groove 90 is machined. Figure 7 is a schematic perspective view showing how the outside region of the groove bottom 91 of the dovetail groove 90 is machined. Figures 8 and 9 are schematic cross-sectional views showing how the position of the tool bit 8 is changed in the width direction of the dovetail groove 90. Figure 10 is a schematic perspective view showing how another part of the groove bottom 91 of the dovetail groove 90 is machined after the position of the tool bit 8 has been changed in the width direction of the dovetail groove 90. Figure 11 is a schematic front view showing an example of a tool bit 8. Figure 12 is an enlarged view of a part of Figure 11. Figure 13 is a schematic plan view illustrating how multiple grooves 91v are formed in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. Figure 14 is a schematic diagram illustrating how the tool bit 8 is attached to the spindle 21 via the tool holder HD. Figure 15 is a schematic perspective view illustrating another example of the workpiece 9. Figure 16 is a schematic front view illustrating the tool bit 8 in the first modification. Figure 17 is a schematic front view illustrating the tool bit 8 in the second modification. Figure 18 is a schematic front view illustrating the tool bit 8 in the third modification. Figure 19 is a schematic perspective view of the tool bit 8 viewed from diagonally below. Figure 20 is a schematic side view illustrating a part of the tool bit 8. Figure 21 is a schematic bottom view illustrating an example of the tool bit 8. Figure 22 is a schematic cross-sectional view illustrating the entry process. Figure 23 is a schematic perspective view illustrating the entry process. Figure 24 is a schematic perspective view illustrating how the orientation of the cutting edge of the tool bit 8 changes after the entry process is performed. Figure 25 is a schematic cross-sectional view illustrating how the position of the tool bit 8 changes in the width direction of the dovetail groove 90. Figure 26 is a schematic cross-sectional view illustrating the state after the first machining cycle has been performed three times. Figure 27 is a schematic perspective view illustrating how the orientation of the cutting edge 81 changes around the first axis AX1.Figure 28 is a schematic perspective view showing the machining of the inside region of the groove bottom 91 of the dovetail groove 90. Figure 29 is a schematic cross-sectional view showing the state after the second machining cycle has been performed twice. Figure 30 is a schematic cross-sectional view showing the seal ring SR positioned in the dovetail groove 90. Figure 31 is a schematic cross-sectional view showing an example in which the dovetail groove 90 is formed in the lid 9b. Figure 32 is a schematic cross-sectional view showing an example of a rough machining process. Figure 33 is a schematic cross-sectional view showing another example of a rough machining process. Figure 34 is a flowchart showing an example of a method for machining a dovetail groove in the first embodiment. Figure 35 is a flowchart showing another example of a method for machining a dovetail groove in the first embodiment.

[0012] Figure 1 shows a workpiece 9 with a roughly machined dovetail groove 90 formed therein. In the example shown in Figure 1, no approach hole with a diameter larger than the opening width W1 of the dovetail groove 90 is formed. In this case, it is difficult to bring the cutting edge of the tool bit to approach the portion indicated by the dashed arrow AR1 in Figure 2. Therefore, in the method for machining the dovetail groove in the first embodiment, a tool bit 8 having a cutting edge portion 81 (see Figure 11) whose cutting edge width increases from the root portion 82 to the tip edge portion 83 is used, and as illustrated in Figure 3, the dovetail groove 90 has an opening width W1 through which the tip edge portion 83 of the cutting edge portion 81 can pass.

[0013] As illustrated in Figures 3 and 4, in the first step ST1, the tool bit 8 is inserted into the rough-machined dovetail groove 90. The first step ST1 is an insertion step. In the example shown in Figures 3 and 4, the insertion step (first step ST1) includes inserting the tool bit 8 into the dovetail groove 90 from outside the dovetail groove 90 of the workpiece 9, through the groove opening OP of the dovetail groove 90.

[0014] As illustrated in Figures 5 to 10, in the second step ST2, the groove bottom 91 of the dovetail groove 90 is cut by the tool bit 8. The second step ST2 is a machining process. Figures 5 to 10 show an example in which the groove bottom 91 of the dovetail groove 90 formed in the workpiece 9 is finished using the tool bit 8.

[0015] As illustrated in Figures 5 to 10, the machining process includes: (1) a step of cutting a portion of the groove bottom 91 of the dovetail groove 90 by moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is entered into the dovetail groove 90 (see Figures 5 and 6); (2) a step of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90 (see Figures 8 and 9); and (3) a step of cutting another portion of the groove bottom 91 by moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is entered into the dovetail groove 90 after the position of the tool bit 8 has been changed in the width direction MR2 of the dovetail groove 90 (see Figure 10).

[0016] In the method for machining the dovetail groove in the first embodiment, the groove bottom 91 of the dovetail groove 90 is suitably cut.

[0017] The dovetail groove machining method in the first embodiment includes a step of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90. Therefore, the groove bottom 91 of the dovetail groove 90 can be suitably cut using a tip edge 83 that has a width smaller than the width of the groove bottom 91 of the dovetail groove 90. Also, as illustrated in Figure 11, the tool bit 8 has a blade portion 81 whose blade width increases from the root portion 82 to the tip edge portion 83. When the blade portion 81 has a flared shape, one end 831 of the tip edge portion 83 of the blade portion 81 in the blade width direction can be easily brought into contact with the depth in the width direction of the dovetail groove 90 (see dashed arrow AR1 in Figure 2). Furthermore, when the width of the tip edge portion 83 is large, the number of times the position of the tool bit 8 needs to be changed in the width direction MR2 of the dovetail groove 90 is reduced.

[0018] In addition, since the dovetail groove 90 has an opening width W1 through which the tip edge 83 of the blade portion 81 can pass, it is not necessary to provide an approach hole in the workpiece 9 with a diameter larger than the opening width W1 of the dovetail groove 90 (see Figure 1).

[0019] (Optional Additional Configurations) Next, with reference to Figures 1 to 35, optional additional configurations that can be adopted in the dovetail groove machining method of the first embodiment will be described.

[0020] (Top portion 84) In the example shown in Figure 12, the tip edge 83 of the blade portion 81 has at least one top portion 84 that contacts the groove bottom 91 of the dovetail groove 90. As illustrated in Figure 13, at least one top portion 84 may form a plurality of grooves 91v (for example, a plurality of microgrooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. In Figure 13, the plurality of grooves 91v are indicated by dashed lines. The grooves 91v may be grooves that can be directly seen by the user, or they may be grooves that cannot be confirmed without using a microscope.

[0021] In the example shown in Figure 12, the tip edge 83 of the blade portion 81 has a plurality of vertices 84 that contact the groove bottom 91 of the dovetail groove 90. More specifically, the tip edge 83 of the blade portion 81 has a plurality of vertices 84 that contact the groove bottom 91 of the dovetail groove 90 along the blade width direction.

[0022] In this case, the multiple tops 84 form multiple grooves 91v (for example, multiple micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. More specifically, the multiple tops 84 move along the extending direction MR1 of the dovetail groove 90, thereby forming multiple grooves 91v (for example, multiple micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90.

[0023] Alternatively, the tip edge 83 of the blade portion 81 may have only one apex 84 that contacts the groove bottom 91 of the dovetail groove 90. In this case, the single apex 84 forms multiple grooves 91v (e.g., multiple micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90. More specifically, the single apex 84 moves along the extending direction MR1 of the dovetail groove 90, then the single apex 84 is repositioned in the width direction MR2 of the dovetail groove 90, and then the single apex 84 moves along the extending direction MR1 of the dovetail groove 90, thereby forming multiple grooves 91v (e.g., multiple micro-grooves) in the groove bottom 91 along the extending direction MR1 of the dovetail groove 90.

[0024] In the example shown in Figure 12, the tip edge 83 of the blade portion 81 has a plurality of peaks 84 and a plurality of valleys 85 that are recessed toward the base portion 82. Each of the plurality of peaks 84 may be made up of a curved edge. Each of the plurality of valleys 85 may be made up of a curved edge. The tip edge 83 of the blade portion 81 may have a wave shape SH having a plurality of peaks 84 and a plurality of valleys 85.

[0025] As illustrated in Figure 12, the width W4 of each peak 84 may be smaller than the width W5 of each valley 85. In the direction of the blade thickness, the line segment 86 connecting the peak 84 and the valley 85 may be inclined with respect to the central axis AT1 of the shaft 87 that supports the blade portion 81. In the example shown in Figure 12, the tip edge 83 has three peaks 84. Alternatively, the tip edge 83 may have four or more peaks 84.

[0026] (Spindle 21) As illustrated in Figure 14, the cutting process (second step ST2) may be performed with the tool bit 8 mounted on a spindle 21 that is rotatable around the first axis AX1 via a tool holder HD. In other words, cutting of the groove bottom 91 may be performed with the tool bit 8 mounted on a spindle 21 that is rotatable around the first axis AX1 via a tool holder HD. In this case, as illustrated in Figure 6, the orientation of the cutting edge 81 can be changed while moving the tool bit 8 along the curved portion 90c of the dovetail groove 90. As illustrated in Figure 14, with the tool bit 8 mounted on the spindle 21 via a tool holder HD, the first axis AX1 may be substantially coaxial with the central axis AT1 of the tool bit 8.

[0027] As illustrated in Figure 6, we assume that the dovetail groove 90 has a curved portion 90c that extends along the curve. In this case, the cutting process (more specifically, cutting the groove bottom 91) includes changing the orientation of the cutting edge 81 while moving the tool bit 8 along the curve by rotating the spindle 21 in accordance with the change in the tangential direction of the curve. More specifically, the cutting process (more specifically, cutting the groove bottom 91) includes substantially maintaining the angle between the cutting edge width direction of the cutting edge 81 and the tangential direction of the curve at a predetermined angle (for example, 90 degrees) while moving the tool bit 8 along the curve.

[0028] Since the tool bit 8 is a non-rotating cutting tool, it does not rotate when it moves along the straight portion 90s of the dovetail groove 90 (see Figure 5). On the other hand, when the tool bit 8 moves along the curved portion 90c of the dovetail groove 90, it is preferable that the orientation of the cutting edge 81 is changed while the tool bit 8 moves along the curved portion 90c (see Figure 6).

[0029] (Groove opening OP) In the example shown in Figure 6, the groove opening OP of the dovetail groove 90 has a constant width Wc along the extending direction MR1 of the dovetail groove 90. Furthermore, the groove opening OP with a constant width Wc itself is used as the opening OP1 for approaching the tool bit 8 (see Figure 3).

[0030] As illustrated in Figure 3, in this specification, the direction from the groove opening OP of the dovetail groove 90 toward the groove bottom 91 of the dovetail groove 90 is defined as the first direction DR1. In the example shown in Figure 3, the first direction DR1 is perpendicular to the plane along the groove opening OP and is the direction toward the groove bottom 91 from the groove opening OP.

[0031] As illustrated in Figure 1, the dovetail groove 90 may have a closed shape when viewed in the first direction DR1. In the dovetail groove machining method of the first embodiment, even when the dovetail groove 90 has a closed shape, the tool bit 8 can be suitably inserted into the dovetail groove 90 through the groove opening OP of the dovetail groove 90.

[0032] As illustrated in Figure 1, the dovetail groove 90 may have a substantially rectangular shape when viewed in the first direction DR1. In other words, the closed shape described above may be substantially rectangular. As illustrated in Figure 1, the substantially rectangular shape may be a rounded rectangular shape. Alternatively, as illustrated in Figure 15, the dovetail groove 90 may have a substantially circular shape when viewed in the first direction DR1. In other words, the closed shape described above may be substantially circular.

[0033] As illustrated in Figure 7, if the dovetail groove 90 has a closed shape (for example, a roughly rectangular shape or a roughly circular shape, etc.) when viewed in the first direction DR1, the above-described machining process (for example, the process of cutting a part of the groove bottom 91 of the dovetail groove 90) may include rotating the blade portion 81 along the extending direction MR1 of the dovetail groove 90 while the blade portion 81 is in contact with the groove bottom 91. More specifically, the above-described machining process (for example, the process of cutting a part of the groove bottom 91 of the dovetail groove 90) may include rotating the blade portion 81 at least once around the region 92 surrounded by the dovetail groove 90 while the blade portion 81 is in contact with the groove bottom 91. As illustrated in Figure 6, rotating the blade portion 81 may include changing the orientation of the blade portion 81 while moving the tool bit 8 along the curved portion 90c of the dovetail groove 90.

[0034] (Blade portion 81) In the example shown in Figure 11, when viewed from the tip 8d of the tool bit 8 toward the base 8p of the tool bit 8, the center of the tip edge 83 of the blade portion 81 is offset from the center of the root portion 82 of the blade portion 81. Also, when viewed in the blade thickness direction, the half-line LN extending from the center of the root portion 82 through the center of the tip edge 83 is inclined with respect to the direction from the base of the tool bit 8 toward the tip of the tool bit 8 (more specifically, when viewed in the blade thickness direction, the half-line LN is inclined with respect to the central axis AT1 of the shaft 87). In this case, as illustrated in Figure 8, one end 831 of the tip edge 83 in the blade width direction can easily approach the widthwise depth of the dovetail groove 90. Also, the amount of lateral protrusion of the other end 832 of the tip edge 83 in the blade width direction is reduced. For this reason, it is easy to enter the dovetail groove 90 through the groove opening OP of the dovetail groove 90. In this specification, the direction parallel to the width direction of the blade portion 81 and extending from one end 831 in the width direction of the tip edge portion 83 to the other end 832 in the width direction of the tip edge portion 83 is defined as the second direction DR2. In this specification, the blade thickness direction (more specifically, the direction perpendicular to the width direction of the blade and opposite to the direction in which the blade portion 81 moves during cutting) is defined as the third direction DR3.

[0035] In the example shown in Figure 11, the blade portion 81 has a flared shape where the blade width increases towards the cutting edge when viewed in the third direction DR3. As illustrated in Figure 11, the blade portion 81 may have a flared shape on one side where the blade width increases from the root portion 82 towards the tip edge portion 83 when viewed in the third direction DR3 (more specifically, a flared shape on one side where the blade width increases towards the cutting edge). When the blade portion 81 has a flared shape on one side, the tip edge portion 83 is easily inserted into the dovetail groove 90 through the groove opening OP of the dovetail groove 90. Alternatively, as illustrated in Figure 16, the blade portion 81 may have a flared shape on both sides where the blade width increases from the root portion 82 towards the tip edge portion 83 when viewed in the third direction DR3 (more specifically, a flared shape on both sides where the blade width increases towards the cutting edge).

[0036] In the examples shown in Figures 12 and 16, the tip edge 83 of the blade portion 81 has a corrugated shape SH having a plurality of peaks 84 and a plurality of valleys 85. Alternatively, as illustrated in Figures 17 and 18, the tip edge of the blade portion 81 may be straight.

[0037] As illustrated in Figure 19, the tip edge 83 of the blade portion 81 may have a plurality of grooves 83v extending in the third direction DR3. In the example shown in Figure 19, the tip edge 83 of the blade portion 81 has a plurality of vertices 84 extending in the third direction DR3 and a plurality of valleys 85 extending in the third direction DR3, and each of the plurality of valleys 85 extending in the third direction DR3 constitutes a groove 83v extending in the third direction DR3. In addition, each of the plurality of vertices 84 extending in the third direction DR3 constitutes a ridge 83r extending in the third direction DR3.

[0038] (Shaft 87) In the examples shown in Figures 11, 16, 17, and 18, the tool bit 8 has a shaft 87 that supports the cutting edge 81.

[0039] In the examples shown in Figures 11 and 17, the center of the tip edge 83 of the blade portion 81 is located away from the central axis AT1 of the shaft 87 when viewed in the blade thickness direction (more specifically, in the third direction DR3). In this case, as illustrated in Figure 8, one end 831 of the tip edge 83 in the blade width direction can easily approach the depth of the dovetail groove 90 in the width direction. Also, the amount of protrusion of the other end 832 of the tip edge 83 of the blade portion 81 from the central axis AT1 of the shaft 87 is small, making it easier for the tip edge 83 to enter the dovetail groove 90 through the groove opening OP of the dovetail groove 90.

[0040] In this specification, the distance between one end 831 of the tip edge 83 of the blade portion 81 in the blade width direction and the central axis AT1 of the shaft 87 is defined as the first distance L1 (see Figure 11), and the distance between the other end 832 of the tip edge 83 of the blade portion 81 in the blade width direction and the central axis AT1 of the shaft 87 is defined as the second distance. In the example shown in Figure 11, the first distance L1 is greater than the second distance (in the example shown in Figure 11, the second distance is zero, but the second distance does not have to be zero). When the first distance L1 is large, one end 831 of the tip edge 83 can easily approach the depth of the dovetail groove 90 in the width direction. Also, when the second distance is small, the tip edge 83 can easily enter the dovetail groove 90 through the groove opening OP of the dovetail groove 90.

[0041] In the examples shown in Figures 11 and 17, the entire tip edge 83 of the blade portion 81 is positioned on one side of the central axis AT1 of the shaft 87, when viewed in the blade thickness direction (more specifically, when viewed in the third direction DR3). Alternatively, a large portion of the tip edge 83 of the blade portion 81 (for example, 3 / 4 or more of the total volume of the tip edge 83 of the blade portion 81) may be positioned on one side of the central axis AT1 of the shaft 87, when viewed in the blade thickness direction (more specifically, when viewed in the third direction DR3). By positioning the entire or a large portion of the tip edge 83 of the blade portion 81 on one side of the central axis AT1 of the shaft 87, the tip edge 83 is made more easily accessible to enter the dovetail groove 90 through the groove opening OP of the dovetail groove 90.

[0042] As illustrated in Figure 20, when viewed in the width direction of the blade portion 81 (more specifically, in the second direction DR2), most of the tip edge portion 83 of the blade portion 81 (for example, 3 / 4 or more of the total volume of the tip edge portion 83 of the blade portion 81) may be positioned on one side of the central axis AT1 of the shaft 87. Alternatively, when viewed in the width direction of the blade portion 81 (more specifically, in the second direction DR2), the entire blade portion 81 may be positioned on one side of the central axis AT1 of the shaft 87.

[0043] As illustrated in Figure 20, the ridge portion 83r of the distal edge portion 83 may be inclined so as to approach the root portion 82 of the blade portion 81 as it extends in the third direction DR3 (more specifically, the direction perpendicular to the blade width direction and opposite to the moving direction of the blade portion 81 during cutting).

[0044] As illustrated in Figure 21, when viewed in the direction along the central axis AT1 of the shaft 87, the entire distal edge portion 83 may be located inside the outer edge 87e of the shaft 87. Alternatively, when viewed in the direction along the central axis AT1 of the shaft 87, one end 831 of the distal edge portion 83 in the blade width direction may be located outside the outer edge 87e of the shaft 87, and the other end 832 of the distal edge portion 83 in the blade width direction may be located inside the outer edge 87e of the shaft 87.

[0045] As illustrated in Figure 21, when viewed in the direction along the central axis AT1 of the shaft 87, the entire distal edge portion 83 may be located within two quadrants centered on the central axis AT1 (or within one quadrant centered on the central axis AT1). Alternatively, when viewed in the direction along the central axis AT1 of the shaft 87, the majority of the distal edge portion 83 (for example, 3 / 4 or more of the total volume of the distal edge portion 83 of the blade portion 81) may be located within two quadrants centered on the central axis AT1 (or within one quadrant centered on the central axis AT1).

[0046] (Entry Process) In the example shown in Figure 22, the entry process (first step ST1) is performed with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) positioned substantially parallel to the width direction of the dovetail groove 90. More specifically, the entry process (first step ST1) includes inserting the tool bit 8 into the dovetail groove 90 through the groove opening OP of the dovetail groove 90 with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) positioned substantially parallel to the width direction of the dovetail groove 90. In the example shown in Figure 22, the width W2 of the tip edge portion 83 (more specifically, the width of the tip edge portion 83 in the direction along the second direction DR2, and more specifically, the distance between one end 831 of the tip edge portion 83 in the blade width direction and the other end 832 of the tip edge portion 83 in the blade width direction) is smaller than the opening width W1 of the dovetail groove 90 (more specifically, the constant width Wc of the groove opening OP). Because the width W2 of the tip edge 83 of the blade portion 81 is smaller than the opening width W1 of the dovetail groove 90, the tip edge 83 can easily enter the dovetail groove 90. Furthermore, even if the blade portion 81 has a flared shape, the entire tip edge 83 of the blade portion 81 can easily enter the dovetail groove 90.

[0047] Alternatively, the entry step (first step ST1) may include inserting the tool bit 8 into the dovetail groove 90 through the groove opening OP of the dovetail groove 90, with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) perpendicular or inclined with respect to the width direction of the dovetail groove 90 (see dashed arrow AR2 in Figure 23). In this case, after the tool bit 8 has entered the dovetail groove 90, before performing the step of cutting a portion of the groove bottom 91 of the dovetail groove 90, the tool bit 8 is rotated around the first axis AX1 so that the blade width direction of the blade portion 81 (more specifically, the second direction DR2) is substantially parallel to the width direction of the dovetail groove 90 (see dashed arrow AR3 in Figure 24).

[0048] In the examples illustrated in FIG. 22 and FIG. 23, the entry step (first step ST1) includes causing the leading edge portion 83 of the blade portion 81 to enter the dovetail groove 90 in a state where the entire blade portion 81 as viewed in the first direction DR1 is positioned inside both side edges of the groove opening OP. The entry step (first step ST1) may include causing the tool bit 8 to enter the dovetail groove 90 by moving the tool bit 8 in a direction substantially parallel to the first direction DR1.

[0049] (Machining Step) In the present specification, a cycle including the step of moving the blade portion 81 along the extending direction MR1 of the dovetail groove 90 in a state where the leading edge portion 83 of the blade portion 81 is in contact with the groove bottom 91 of the dovetail groove 90, and the step of changing the position of the blade portion 81 in the width direction MR2 of the dovetail groove 90, is defined as a first machining cycle.

[0050] As illustrated in FIG. 1 and FIG. 15, a case is assumed where the dovetail groove 90 has a closed shape (e.g., a substantially rectangular shape, a substantially circular shape, etc.). More specifically, a case is assumed where the dovetail groove 90 has a closed loop shape. In this case, the step of moving the blade portion 81 along the extending direction MR1 of the dovetail groove 90 in the first machining cycle may include orbiting the blade portion 81 along the extending direction MR1 of the dovetail groove 90 (more specifically, causing the blade portion 81 to make at least one full revolution around the periphery of the region 92 enclosed by the dovetail groove 90).

[0051] As indicated by the dashed arrow AR4 in FIG. 25, the step of changing the position of the blade portion 81 in the width direction MR2 of the dovetail groove 90 may include executing the following in sequence: (1) separating the blade portion 81 from the groove bottom 91, (2) moving the blade portion 81 in the blade width direction (more specifically, the second direction DR2 or the direction opposite to the second direction DR2), and (3) bringing the blade portion 81 into contact with the groove bottom 91.

[0052] The machining step (second step ST2) may include repeatedly executing the above-described first machining cycle. For example, the machining step (second step ST2) may include shifting the blade portion 81 by a predetermined distance in the blade width direction every time the blade portion 81 makes one full revolution along the dovetail groove 90 while in contact with the groove bottom 91.

[0053] The processing step (second step ST2) may include repeating the above-described first processing cycle two or more times, three or more times, four or more times, or five or more times.

[0054] Figure 26 shows the state after the first processing cycle described above has been performed three times.

[0055] The machining process (second step ST2) may include a step of changing the orientation of the cutting edge 81 around the first axis AX1 after the first machining cycle has been performed two or more times. More specifically, the machining process (second step ST2) may include a step of changing the orientation of the cutting edge 81 around the first axis AX1 by a predetermined angle (for example, 180 degrees) after the first machining cycle has been performed two or more times. Figure 27 shows the process of changing the orientation of the cutting edge 81 in progress.

[0056] The step of changing the orientation of the blade portion 81 (more specifically, the step of changing the orientation of the blade portion 81 by a predetermined angle (for example, 180 degrees)) is preferably performed when the entire tool bit 8 is located outside the dovetail groove 90. In this case, the machining step (second step ST2) may include performing, in this order: (1) after the first machining cycle has been performed two or more times, moving the entire tool bit 8 outside the dovetail groove 90; (2) changing the orientation of the blade portion 81 around the first axis AX1 (more specifically, changing the orientation of the blade portion 81 around the first axis AX1 by a predetermined angle (for example, 180 degrees)); and (3) re-entering the tool bit 8 into the dovetail groove 90.

[0057] Alternatively, if the size of the dovetail groove 90 is sufficiently large, the step of changing the orientation of the blade portion 81 (more specifically, the step of changing the orientation of the blade portion 81 by a predetermined angle (e.g., 180 degrees)) may be performed while the tool bit 8 is entered into the dovetail groove 90.

[0058] In the example shown in Figure 27, if the tool bit 8 retracts from the top of the first side wall 99-1 of the workpiece 9 outside the dovetail groove 90, and then the tool bit 8 re-enters the dovetail groove 90 at the top of the second side wall 99-2 opposite the first side wall 99-1, the step of changing the orientation of the cutting edge 81 around the first axis AX1 may be omitted. In other words, the step of changing the orientation of the cutting edge 81 (more specifically, the step of changing the orientation of the cutting edge 81 by a predetermined angle) is not essential.

[0059] In this specification, in the first machining cycle, the direction in which the cutting edge 81 moves along the extending direction MR1 of the dovetail groove 90 is defined as the first movement direction MD1 (see Figure 10), and the direction opposite to the first movement direction MD1 is defined as the second movement direction MD2 (see Figure 28). Furthermore, in this specification, a cycle including the steps of moving the cutting edge 81 in the second movement direction MD2 while the tip edge 83 of the cutting edge 81 is in contact with the groove bottom 91 of the dovetail groove 90, and changing the position of the cutting edge 81 in the width direction MR2 of the dovetail groove 90 is defined as the second machining cycle.

[0060] As illustrated in Figures 1 and 15, we assume that the dovetail groove 90 has a closed shape (for example, a roughly rectangular shape, a roughly circular shape, etc.). More specifically, we assume that the dovetail groove 90 has a closed loop shape. In this case, as illustrated in Figure 28, the step of moving the cutting edge 81 in the second movement direction MD2 of the second machining cycle may include rotating the cutting edge 81 along the extending direction of the dovetail groove 90 (more specifically, the cutting edge 81 making at least one rotation around the region 92 surrounded by the dovetail groove 90).

[0061] The machining process (second step ST2) may include repeatedly executing the second machining cycle described above. For example, the machining process (second step ST2) may include shifting the blade portion 81 in the blade width direction by a predetermined distance each time the blade portion 81 completes one revolution along the dovetail groove 90 in the second movement direction MD2 while in contact with the groove bottom 91.

[0062] The machining process (second step ST2) may include a step of changing the orientation of the blade portion 81 (more specifically, a step of changing the orientation of the blade portion 81 by a predetermined angle (for example, 180 degrees) around the first axis AX1), followed by repeatedly executing the second machining cycle described above. The machining process (second step ST2) may also include repeatedly executing the second machining cycle described above two or more times, three or more times, four or more times, or five or more times.

[0063] Figure 29 shows the state after the second processing cycle described above has been performed twice.

[0064] It is preferable that the machining process (second step ST2) is performed such that substantially the entire groove bottom 91 of the dovetail groove 90 is cut by the tip edge 83 of the cutting edge 81. More specifically, it is preferable that the first machining cycle described above is performed multiple times, and the second machining cycle described above is performed multiple times, so that substantially the entire groove bottom 91 of the dovetail groove 90 is cut by the tip edge 83 of the cutting edge 81. In the examples shown in Figures 7 and 10, performing the first machining cycle multiple times includes cutting one side of the groove bottom 91 of the dovetail groove 90, RG1 (e.g., the outside region of the groove bottom 91), by the tip edge 83 of the cutting edge 81. In the example shown in Figure 28, performing the second machining cycle multiple times includes cutting the other side of the groove bottom 91 of the dovetail groove 90, RG2 (e.g., the inside region of the groove bottom 91), by the tip edge 83 of the cutting edge 81.

[0065] (Seal ring SR) As illustrated in Figure 30, the dovetail groove 90 may be a seal ring receiving groove 90a. In the first embodiment, the groove bottom 91 of the dovetail groove 90 is cut by the tip edge 83 of the cutting edge 81 (more specifically, the groove bottom 91 of the dovetail groove 90 is finished by the tool bit 8). Thus, a smooth surface suitable for sealing is obtained by the seal ring SR.

[0066] (Workpiece 9) Workpiece 9 may be a case 9a (see Figure 1), or it may be a fluid flange. In the example shown in Figure 1, the dovetail groove 90 (more specifically, the seal ring receiving groove 90a) is formed in the case 9a. As illustrated in Figure 2, the dovetail groove 90 may be formed on the top surface 99s of the side wall 99 of the case 9a.

[0067] Alternatively, as illustrated in Figure 31, the workpiece 9 may be a lid 9b. In this case, the dovetail groove 90 (more specifically, the seal ring receiving groove 90a) is formed in the lid 9b. As illustrated in Figure 31, the dovetail groove 90 (more specifically, the seal ring receiving groove 90a) may be formed on the back surface 98s of the lid 9b.

[0068] In the example shown in Figure 8, the workpiece 9 has multiple surfaces that define the dovetail groove 90. More specifically, the workpiece 9 has a first surface 97a that defines the first side of the dovetail groove 90, a second surface 97b that defines the second side of the dovetail groove 90, and a third surface 97c that defines the groove bottom 91 of the dovetail groove 90. Cutting the groove bottom 91 is equivalent to cutting the third surface 97c.

[0069] The dovetail groove 90 is defined by the first surface 97a, the second surface 97b, and the third surface 97c. In the example shown in Figure 3, the second surface 97b is positioned inward from the first surface 97a. More specifically, the second surface 97b is the inner circumferential surface of the dovetail groove 90, and the first surface 97a is the outer circumferential surface of the dovetail groove 90.

[0070] The angle between the first surface 97a and the third surface 97c is, for example, less than 80 degrees or less than 70 degrees. The angle between the second surface 97b and the third surface 97c is, for example, less than 80 degrees or less than 70 degrees. A curve may be formed between the first surface 97a and the third surface 97c. A curve may be formed between the second surface 97b and the third surface 97c.

[0071] (Rough machining process) The method for machining the dovetail groove in the first embodiment may include a rough machining process. The rough machining process is performed before the entry process (first step ST1).

[0072] More specifically, the method for machining the dovetail groove in the first embodiment (more specifically, the rough machining step) includes forming a first surface 97a defining the first side portion of the dovetail groove 90 and a second surface 97b defining the second side portion of the dovetail groove 90 using at least one cutting tool.

[0073] In the example shown in Figure 32, the method for machining the dovetail groove in the first embodiment (more specifically, the rough machining step) includes using a milling tool T1 to form a first surface 97a defining the first side portion of the dovetail groove 90 and a second surface 97b defining the second side portion of the dovetail groove 90.

[0074] Alternatively, the method for machining the dovetail groove in the first embodiment (more specifically, the rough machining step) may include forming a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90 using at least one non-rotating tool (for example, the tool bit 8 described above, or another tool bit T2 for rough machining), as illustrated in Figure 33.

[0075] The rough machining process for rough machining the dovetail groove is not limited to the examples shown in Figures 32 and 33. The rough machining process for rough machining the dovetail groove can be carried out using any known method.

[0076] The machining method for the dovetail groove 90 in the first embodiment may include (1) a step of forming a roughly machined dovetail groove 90 using a rough machining tool T (for example, a milling tool T1) held on the spindle 21, and a step of replacing the rough machining tool T (for example, a milling tool T1) held on the spindle 21 with a tool holder HD to which a tool bit 8 is attached, using a tool changer 6 (see Figure 37). The step of forming a roughly machined dovetail groove 90 may include forming a first surface 97a defining the first side portion of the dovetail groove 90 and a second surface 97b defining the second side portion of the dovetail groove 90 using a rough machining tool T (for example, a milling tool T1) held on the spindle 21. The step of forming a roughly machined dovetail groove 90 may also include forming a rough groove bottom 91. After performing the step of replacing the roughing tool T held on the spindle 21 with a tool holder HD to which the tool bit 8 is attached, the entry step (first step ST1) described above may be performed.

[0077] When the roughing tool T (for example, a milling tool T1) and the tool bit 8 are exchanged using a tool changer 6, both roughing and finishing of the dovetail groove can be efficiently performed using a single machine tool 1.

[0078] Referring to Figure 35, an example of a method for machining a dovetail groove in the first embodiment will be described. In the example shown in Figure 35, the method for machining a dovetail groove comprises (1) a step of forming a roughly machined dovetail groove 90 using a roughing tool T (for example, a milling tool T1) (see Figure 32 or Figure 33), and (2) a step of replacing the roughing tool T (for example, a milling tool T1) held on the spindle 21 with a tool bit 8 (more specifically, a tool holder HD to which the tool bit 8 is attached). After the replacement step, the entry step (first step ST1) and the machining step (second step ST2) described above are performed.

[0079] The machining process described above (second step ST2) includes machining one side of the groove bottom 91 of the dovetail groove 90 (for example, one of the outside region and the inside region of the groove bottom 91) with the tool bit 8. Machining one side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include performing the above-described first machining cycle multiple times. More specifically, machining one side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include rotating the tool bit 8 in a first movement direction MD1 along the extending direction MR1 of the dovetail groove 90 while the tip edge 83 of the tool bit 8 is in contact with the groove bottom 91, and shifting the tool bit 8 by a predetermined distance in the groove width direction with each rotation.

[0080] In the example shown in Figure 35, the method for machining the dovetail groove includes machining one side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8, then retracting the tool bit 8 outside the dovetail groove 90, and rotating the spindle 21 around the first axis AX1 by a predetermined angle (for example, 180 degrees) while the tool bit 8 is retracted outside the dovetail groove 90. This rotation changes the orientation of the cutting edge 81 by a predetermined angle (for example, 180 degrees) around the first axis AX1.

[0081] In the example shown in Figure 35, the method for machining the dovetail groove includes changing the orientation of the cutting edge 81 by a predetermined angle (for example, 180 degrees) around the first axis AX1, and then re-entering the tool bit 8 into the dovetail groove 90. However, if the tool bit 8 retracts from the top of the first side wall 99-1 of the workpiece 9 outside the dovetail groove 90 (see Figure 27), and then the tool bit 8 re-enters the dovetail groove 90 at the top of the second side wall 99-2 opposite the first side wall 99-1, the step of changing the orientation of the cutting edge 81 around the first axis AX1 may be omitted.

[0082] In the example shown in Figure 35, the method for machining the dovetail groove includes, after the tool bit 8 re-enters the dovetail groove 90, machining the other side of the groove bottom 91 of the dovetail groove 90 (for example, the other of the outside and inside regions of the groove bottom 91) with the tool bit 8. Machining the other side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include performing the above-described second machining cycle multiple times. More specifically, machining the other side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8 may include rotating the tool bit 8 in a second movement direction MD2 opposite to the first movement direction MD1 along the extending direction of the dovetail groove 90, with the tip edge 83 of the tool bit 8 in contact with the groove bottom 91, and shifting the tool bit 8 by a predetermined distance in the groove width direction with each rotation.

[0083] In the example shown in Figure 35, the method for machining the dovetail groove includes machining the other side of the groove bottom 91 of the dovetail groove 90 with the tool bit 8, and then retracting the tool bit 8 outside the dovetail groove 90.

[0084] (Second Embodiment) The machine tool 1 in the second embodiment will be described with reference to Figures 1 to 41. Figure 36 is a schematic perspective view showing the machine tool 1 in the second embodiment. Figure 37 is a schematic front view showing the tool change process M2 being executed. Figure 38 is a schematic diagram showing how the control device 5 can control multiple control target devices. Figures 39 to 41 are schematic front views showing a part of the machine tool 1 in the second embodiment.

[0085] The second embodiment will be described primarily in terms of its differences from the first embodiment. On the other hand, in the second embodiment, repetitive explanations of matters already explained in the first embodiment will be omitted. Therefore, it goes without saying that even if not explicitly explained in the second embodiment, matters already explained in the first embodiment can be applied to the second embodiment. Furthermore, matters explained in the second embodiment can also be adopted in the first embodiment.

[0086] As illustrated in Figure 36, the machine tool 1 in the second embodiment comprises a machining head 2, a workpiece support device 3, a moving device 4, and a control device 5.

[0087] The machining head 2 holds the tool holder HD to which the tool bit 8 is attached. As illustrated in Figures 11, 16, 17, and 18, the tool bit 8 has a cutting edge 81 whose cutting edge width increases from the root 82 to the tip edge 83.

[0088] The workpiece support device 3 supports the workpiece 9.

[0089] The moving device 4 moves the machining head 2 relative to the workpiece support device 3.

[0090] The control device 5 controls the moving device 4. The control device 5 can perform the machining process M3 (see, for example, Figures 3 to 6).

[0091] The machining process M3 includes: (1) process M3-1 (see Figures 3 and 4) of inserting the tool bit 8 into the roughly machined dovetail groove 90 formed in the workpiece 9; (2) process M3-2 (see, for example, Figures 5 and 6) of cutting a portion of the groove bottom 91 of the dovetail groove 90 by moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is inserted into the dovetail groove 90; (3) process M3-3 (see, for example, Figures 8 and 9) of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90; and (4) process M3-4 (see, for example, Figure 10) of cutting another portion of the groove bottom 91 by moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 after the position of the tool bit 8 has been changed in the width direction MR2 of the dovetail groove 90 while the tool bit 8 is inserted into the dovetail groove 90.

[0092] In the second embodiment, the machine tool 1 can suitably cut the groove bottom 91 of the dovetail groove 90 using the tool bit 8.

[0093] In the second embodiment, the control device 5 can perform the process of changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90, so that the groove bottom 91 of the dovetail groove 90 can be suitably cut using the tip edge 83 which has a width smaller than the width of the groove bottom 91 of the dovetail groove 90. Also, as illustrated in Figure 8, the tool bit 8 has a blade portion 81 whose blade width increases from the root portion 82 to the tip edge portion 83. When the blade portion 81 has a flared shape, one end 831 of the tip edge portion 83 of the blade portion 81 in the blade width direction can be easily brought into contact with the depth of the dovetail groove 90 in the width direction. Also, when the width of the tip edge portion 83 is large, the number of times the position of the tool bit 8 needs to be changed in the width direction MR2 of the dovetail groove 90 is reduced.

[0094] (Optional Additional Configurations) Next, with reference to Figures 1 to 41, optional additional configurations that can be adopted in the machine tool 1 in the second embodiment will be described.

[0095] (Machining head 2) As illustrated in Figure 14, the machining head 2 comprises a spindle 21 and a support 23 that rotatably supports the spindle 21 around the first axis AX1. The spindle 21 is capable of holding a tool holder HD to which a tool bit 8 is attached.

[0096] The machine tool 1 (more specifically, the machining head 2) includes a rotary drive device 11 that rotates the spindle 21 around the first axis AX1. The rotary drive device 11 may include a motor 11m that rotates the spindle 21 around the first axis AX1.

[0097] In the example shown in Figure 36, machine tool 1 is a vertical machining center. Alternatively, machine tool 1 may be a horizontal machining center or a multi-tasking machine.

[0098] (Work support device 3) In the example shown in Figure 36, the work support device 3 includes a table 31 for supporting the workpiece 9. The work support device 3 may also include a table rotation device 35 for rotating the table 31, and / or a tilting device for tilting the table 31. Alternatively or additionally, the work support device 3 may include a chuck for gripping the workpiece 9.

[0099] (Moving device 4) The moving device 4 moves the machining head 2 relative to the workpiece support device 3. The moving device 4 moves the machining head 2. Alternatively, or additionally, the moving device 4 may move the table 31 (or the chuck that grips the workpiece 9) that supports the workpiece 9.

[0100] The moving device 4 may include a first moving device 41 that moves the machining head 2 in a direction along the Z-axis perpendicular to the horizontal plane. The first moving device 41 may include, for example, a Z-axis motor that moves the machining head 2 in a direction along the Z-axis.

[0101] The moving device 4 may include a second moving device 42 that moves the machining head 2 in a direction along the X-axis parallel to the horizontal plane. The second moving device 42 may include, for example, an X-axis motor that moves the machining head 2 in a direction along the X-axis.

[0102] The moving device 4 may include a third moving device 43 that moves the machining head 2 in a direction along the Y-axis parallel to the horizontal plane. The third moving device 43 may include, for example, a Y-axis motor that moves the machining head 2 in a direction along the Y-axis. In the example shown in Figure 36, the Y-axis is perpendicular to both the X-axis and the Z-axis.

[0103] In the example shown in Figure 36, the moving device 4 is capable of moving the machining head 2 in three dimensions. Alternatively, the moving device 4 may be a device that moves the machining head 2 in two dimensions or one dimension. Alternatively, or additionally, the moving device 4 may be capable of moving the table 31 in one dimension, two dimensions, or three dimensions.

[0104] (Tool changing device 6) The machine tool 1 may be equipped with a tool changing device 6. As illustrated in Figure 37, the tool changing device 6 can replace a roughing tool T (for example, a milling tool T1) held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) with a tool holder HD to which a tool bit 8 is attached. The tool changing device 6 can also replace the tool holder HD held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) with another tool holder to which another tool is attached.

[0105] The tool changing device 6 may include a tool changing arm 61, an arm rotating device 63 for rotating the tool changing arm 61, and an arm moving device 65 for moving the tool changing arm 61 linearly. The arm rotating device 63 rotates the tool changing arm 61 around the second axis AX2. The arm moving device 65 moves the tool changing arm 61 in a direction parallel to the second axis AX2.

[0106] (Control device 5) The control device 5 controls the moving devices 4 (for example, the first moving device 41, the second moving device 42, and / or the third moving device 43). Additionally, the control device 5 may control the rotary drive device 11. Additionally, the control device 5 may control the tool changer 6 and / or the table rotation device 35.

[0107] An example of the control device 5 will be described with reference to Figure 38. In the example shown in Figure 38, the control device 5 comprises an arithmetic unit 50, a memory 52, and a communication circuit 54. The control device 5 may also include an input device 56 and / or a display 57. In the example shown in Figure 38, the arithmetic unit 50, the memory 52, the communication circuit 54, the input device 56, and the display 57 are connected to each other via a bus 58.

[0108] The memory 52 is a storage medium readable by the arithmetic unit 50. The memory 52 may be, for example, a non-volatile or volatile semiconductor memory such as RAM, ROM, or flash memory, or it may be a magnetic disk or other type of memory.

[0109] Memory 52 stores the processing program PM and various data. Memory 52 may be distributed across multiple locations. Memory 52 may include cloud storage accessible via a network.

[0110] The arithmetic unit 50 includes at least one hardware processor 50a (for example, at least one CPU). The control device 5 (more specifically, the arithmetic unit 50) generates a plurality of control commands by executing a machining program PM stored in the memory 52. ​​In this specification, the execution of the machining program PM by the control device 5 (more specifically, the arithmetic unit 50) includes the execution of the machining program PM by the control device 5 (more specifically, the arithmetic unit 50) via an arithmetic program. In other words, the machining program PM may be processed (in other words, interpreted) by the control device 5 by executing an arithmetic program.

[0111] In the example shown in Figure 38, the input device 56 includes a touch panel 56a on the display 57. In other words, the display 57 is a display with a touch panel. Note that the input device 56 is not limited to the touch panel 56a on the display 57. For example, the input device 56 may include a button 56b, a switch, a lever, a pointing device such as a mouse, and / or a keyboard.

[0112] The communication circuit 54 transmits multiple control commands generated by the execution of the processing program PM to multiple controlled devices (for example, the moving device 4 and the rotary drive device 11).

[0113] The control device 5 is capable of executing machining process M3. Machining process M3 is, for example, a finishing process. In the example shown in Figure 40, machining process M3 includes transmitting a plurality of control commands SB to at least the moving device 4 so that the groove bottom 91 of the dovetail groove 90 is cut by the tool bit 8. More specifically, machining process M3 includes (1) process M3-1 (see Figures 3 and 4) which involves moving the tool bit 8 into the dovetail groove 90 through the groove opening OP of the dovetail groove 90 in a rough state, (2) process M3-2 (see Figures 5 and 6) which involves moving the tool bit 8 along the extending direction MR1 of the dovetail groove 90 while the tool bit 8 is inside the dovetail groove 90, thereby cutting a portion of the groove bottom 91 of the dovetail groove 90, and (3) moving the tool bit in the width direction MR2 of the dovetail groove 90. The process includes transmitting at least a plurality of control commands SB to the moving device 4 so that the following are executed in this order: (4) after the position of the tool bit 8 has been changed in the width direction MR2 of the dovetail groove 90, the tool bit 8 is moved along the extending direction MR1 of the dovetail groove 90, thereby cutting another part of the groove bottom 91 (see Figure 10).

[0114] As illustrated in Figure 22, the process M3-1 for inserting the tool bit 8 into the dovetail groove 90 may include transmitting a plurality of control commands SB (e.g., a first group of control commands) to the moving device 4 so that the tool bit 8 enters the dovetail groove 90 with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) positioned substantially parallel to the width direction of the dovetail groove 90. In this case, the moving device 4, which receives a plurality of control commands SB (e.g., a first group of control commands) from the control device 5, moves the machining head 2 relative to the workpiece support device 3 so that the tool bit 8 enters the dovetail groove 90 with the blade width direction of the blade portion 81 positioned substantially parallel to the width direction of the dovetail groove 90.

[0115] Alternatively, as illustrated in Figure 23, the process M3-1 for inserting the tool bit 8 into the dovetail groove 90 may include transmitting a plurality of control commands SB to the moving device 4 so that the tool bit 8 enters the dovetail groove 90 with the blade width direction of the blade portion 81 (more specifically, the second direction DR2) perpendicular or inclined with respect to the width direction of the dovetail groove 90. In this case, after the tool bit 8 enters the dovetail groove 90, the control device 5 performs a process to rotate the tool bit 8 around the first axis AX1 so that the blade width direction of the blade portion 81 (more specifically, the second direction DR2) is substantially parallel to the width direction of the dovetail groove 90 (see dashed arrow AR3 in Figure 24).

[0116] The process M3-2 (see Figure 6) for cutting a portion of the groove bottom 91 of the dovetail groove 90 may include transmitting a plurality of control commands SB to the moving device 4 and the rotary drive device 11 so that the orientation of the blade portion 81 is changed as the tool bit 8 moves along the curved portion 90c (see Figure 6) of the dovetail groove 90 while the blade portion 81 is in contact with the groove bottom 91. In this case, the moving device 4 and the rotary drive device 11, which receive the plurality of control commands SB from the control device 5, may rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 so that the angle between the direction of movement of the blade portion 81 and the width direction of the blade portion 81 is substantially maintained at a predetermined angle (for example, 90 degrees).

[0117] The process M3-2 (see Figure 7) for cutting a portion of the groove bottom 91 of the dovetail groove 90 may include transmitting a plurality of control commands SB to the moving device 4 and the rotary drive device 11 so that the blade portion 81 rotates at least once around the region 92 surrounded by the dovetail groove 90 while the blade portion 81 is in contact with the groove bottom 91. In this case, the moving device 4 and the rotary drive device 11, which receive the plurality of control commands SB from the control device 5, may rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 so that the angle between the direction of movement of the blade portion 81 and the width direction of the blade portion 81 is substantially maintained at a predetermined angle (for example, 90 degrees) while the blade portion 81 rotates at least once around the region 92 surrounded by the dovetail groove 90.

[0118] The process M3-3 (see Figures 8 and 9) for changing the position of the tool bit 8 in the width direction MR2 of the dovetail groove 90 may include sending a plurality of control commands SB to the moving device 4 so that the tool bit 8 moves in the width direction MR2 of the dovetail groove 90. In this case, the moving device 4, which receives the plurality of control commands SB from the control device 5, moves the machining head 2 relative to the workpiece support device 3 so that the position of the tool bit 8 is changed in the width direction MR2 of the dovetail groove 90.

[0119] The process M3-4 (see Figure 10) for cutting another portion of the groove bottom 91 of the dovetail groove 90 may include sending a plurality of control commands SB to the moving device 4 and the rotary drive device 11 so that, after the process M3-3 for changing the position of the tool bit 8 is performed, the cutting edge 81 is in contact with the groove bottom 91 and the cutting edge 81 rotates at least once around the region 92 surrounded by the dovetail groove 90. In this case, the moving device 4 and the rotary drive device 11, which receive the plurality of control commands SB from the control device 5, may rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 so that the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees) and the cutting edge 81 rotates at least once around the region 92 surrounded by the dovetail groove 90.

[0120] The machining process M3 may include transmitting a plurality of control commands SB (e.g., a second group of control commands) to the moving device 4 and the rotary drive device 11 so that the first machining cycle described above is executed multiple times. The first machining cycle may be performed while the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees).

[0121] The machining process M3 may include transmitting a plurality of control commands SB (e.g., a third group of control commands) to the moving device 4 and the rotary drive device 11 so that the orientation of the cutting edge 81 is changed by a predetermined angle (e.g., 180 degrees) around the first axis AX1 after the first machining cycle described above has been performed multiple times. More specifically, the machining process M3 may include transmitting a plurality of control commands SB (e.g., a third group of control commands) to the moving device 4 and the rotary drive device 11 so that the following are performed in this order after the first machining cycle described above has been performed multiple times: retracting the tool bit 8 out of the dovetail groove 90, rotating the tool bit 8 by a predetermined angle (e.g., 180 degrees) around the first axis AX1 so that the orientation of the cutting edge 81 is changed by a predetermined angle (e.g., 180 degrees), and re-entering the tool bit 8 into the dovetail groove 90.

[0122] The machining process M3 may include transmitting a plurality of control commands SB (e.g., a fourth group of control commands) to the moving device 4 and the rotary drive device 11 so that the second machining cycle described above is executed multiple times. The second machining cycle may be performed while the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 is substantially maintained at a predetermined angle (e.g., 90 degrees).

[0123] The machining process M3 may include transmitting a plurality of control commands SB to the moving device 4 and the rotary drive device 11 such that the first machining cycle described above is executed multiple times, thereafter the orientation of the cutting edge 81 is changed around the first axis AX1, and thereafter the second machining cycle described above is executed multiple times. Each of the first and second machining cycles may be performed while substantially maintaining the angle between the direction of movement of the cutting edge 81 and the width direction of the cutting edge 81 at a predetermined angle (for example, 90 degrees). The first machining cycle may include cutting one of the outside and inside regions of the groove bottom 91 of the dovetail groove 90 with the tip edge 83 of the cutting edge 81, and the second machining cycle may include cutting the other of the outside and inside regions of the groove bottom 91 of the dovetail groove 90 with the tip edge 83 of the cutting edge 81.

[0124] The control device 5 may be capable of performing a rough machining process M1. In the example shown in Figure 41, the rough machining process M1 includes transmitting a plurality of control commands SC (e.g., a fifth group of control commands) to the moving device 4 and the rotary drive device 11 so that a rough machining tool T (e.g., a milling tool T1) forms a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90. More specifically, the rough machining process M1 includes (1) transmitting a plurality of control commands SC (e.g., a fifth group of control commands) to the moving device 4 and the rotary drive device 11 so that a milling tool T1 rotating around the first axis AX1 forms a first surface 97a defining the first side of the dovetail groove 90 (see Figure 32) and a second surface 97b defining the second side of the dovetail groove 90 (see Figure 32).

[0125] The moving device 4 and the rotary drive device 11, which receive multiple control commands SC (for example, control commands of the fifth group), rotate the spindle 21 around the first axis AX1 while moving the machining head 2 relative to the workpiece support device 3 so that a first surface 97a defining the first side of the dovetail groove 90 and a second surface 97b defining the second side of the dovetail groove 90 are formed.

[0126] The control device 5 may be capable of performing a tool change operation M2. In the example shown in Figure 37, the tool change operation M2 includes transmitting a plurality of control commands SD (e.g., a sixth group of control commands) to the transfer device 4 and the tool change device 6 so that a roughing tool T (e.g., a milling tool T1) held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) is replaced with a tool holder HD to which a tool bit 8 is attached.

[0127] The moving device 4 and the tool changing device 6, which receive multiple control commands SD (for example, control commands of the sixth group), replace the roughing tool T (for example, a milling tool T1) held on the machining head 2 (more specifically, the spindle 21 of the machining head 2) with a tool holder HD to which a tool bit 8 is attached.

[0128] After the tool change process M2 is executed, the control device 5 executes the machining process M3 described above.

[0129] (Tool bit 8) In the examples shown in Figures 11 and 16, the tool bit 8 comprises (1) a blade portion 81 whose blade width increases from the base portion 82 to the tip edge portion 83, and (2) a shaft 87 that supports the blade portion 81.

[0130] In the examples shown in Figures 12 and 16, the tip edge 83 of the blade portion 81 has a plurality of tops 84 that are in contact with the groove bottom 91 of the dovetail groove 90.

[0131] Since the tool bit 8 has already been described in the first embodiment, a repeated explanation of the tool bit 8 will be omitted.

[0132] The present invention is not limited to the embodiments or modifications described above, and it is clear that each embodiment or modification can be appropriately modified or changed within the scope of the technical concept of the present invention. Furthermore, the various technologies used in each embodiment or modification can be applied to other embodiments or other modifications, as long as no technical inconsistencies arise. In addition, any optional additional configurations in each embodiment or modification can be omitted as appropriate.

[0133] 1...Machine tool, 2...Machining head, 3...Workpiece support device, 4...Moving device, 5...Control device, 6...Tool changer, 8...Tool bit, 8d...Tip, 8p...Base, 9...Workpiece, 9a...Case, 9b...Lid, 11...Rotary drive device, 11m...Motor, 21...Spindle, 23...Support, 31...Table, 35...Table rotation device, 41...First moving device, 42...Second moving device, 43...Third moving device, 50...Calculation unit, 50a...Hardware processor, 52...Memory, 54...Communication circuit, 56...Input device, 56a...Touch Panel, 56b...button, 57...display, 58...bus, 61...tool change arm, 63...arm rotation device, 65...arm movement device, 81...blade part, 82...root part, 83...tip edge part, 83r...ridge part, 83v...groove part, 84...top part, 85...valley part, 86...line segment, 87...shaft, 87e...outer edge, 90...dovetail groove, 90a...seal ring receiving groove, 90c...curved part, 90s...straight part, 91...groove bottom, 91v...groove, 92...area surrounded by dovetail groove, 97a...first surface, 97b...second surface, 97c...third surface, 98s...back surface, 99 ...side wall, 99-1...first side wall, 99-2...second side wall, 99s...top surface, 831...one end, 832...other end, AT1...central axis, AX1...first axis, AX2...second axis, DR1...first direction, DR2...second direction, DR3...third direction, HD...tool holder, L1...first distance, LN...half-line, M1...rough machining process, M2...tool change process, M3...machining process, M3-1...process of inserting the tool bit into the dovetail groove, M3-2...process of cutting a part of the groove bottom of the dovetail groove, M3-3...process of changing the position of the tool bit 8 in the width direction of the dovetail groove, M 3-4...Process for cutting another part of the groove bottom, MD1...First movement direction, MD2...Second movement direction, MR1...Extension direction of the dovetail groove, MR2...Width direction of the dovetail groove, OP...Groove opening, OP1...Approach opening, PM...Machining program, RG1...One side of the groove bottom of the dovetail groove, RG2...The other side of the groove bottom of the dovetail groove, SB, SC, SD...Control command, SH...Wave shape, SR...Seal ring, ST1...First step, ST2...Second step, T...Roughing tool, T1...Milling tool, T2...Tool bit, W1...Opening width, Wc...Constant width

Claims

1. A method for machining a dovetail groove, comprising the steps of: inserting a tool bit into a roughly machined dovetail groove; moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove to cut a portion of the groove bottom of the dovetail groove; changing the position of the tool bit in the width direction of the dovetail groove; and, after the position of the tool bit has been changed in the width direction of the dovetail groove, moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove to cut another portion of the groove bottom, wherein the tool bit has a cutting edge whose cutting width increases from the root to the tip edge, and the dovetail groove has an opening width through which the tip edge can pass.

2. The method for machining a dovetail groove according to claim 1, wherein the tip edge of the blade portion has a plurality of vertices that contact the bottom of the groove, and the plurality of vertices form a plurality of grooves in the bottom of the groove along the extending direction of the dovetail groove.

3. The method for machining a dovetail groove according to claim 1, wherein the tip edge of the blade portion has a single apex that contacts the bottom of the groove, and the single apex forms a plurality of grooves in the bottom of the groove along the extending direction of the dovetail groove.

4. The method for machining a dovetail groove according to any one of claims 1 to 3, wherein the cutting of the groove bottom is performed with the tool bit mounted on a spindle rotatable around a first axis via a tool holder.

5. The method for machining a dovetail groove according to any one of claims 1 to 4, wherein the groove opening of the dovetail groove has a constant width along the extending direction of the dovetail groove, and the groove opening having a constant width itself is used as an approach opening for the tool bit.

6. The method for machining a dovetail groove according to any one of claims 1 to 4, wherein the direction from the groove opening of the dovetail groove toward the groove bottom is defined as the first direction, and the dovetail groove has a closed shape when viewed in the first direction.

7. The method for machining a dovetail groove according to claim 6, wherein the step of cutting a portion of the groove bottom of the dovetail groove includes rotating the cutting blade along the extending direction of the dovetail groove while the cutting blade is in contact with the groove bottom.

8. The method for machining a dovetail groove according to claim 4, wherein the step of inserting the tool bit into the rough-machined dovetail groove includes inserting the tool bit into the dovetail groove with the blade width direction of the blade portion perpendicular or inclined with respect to the width direction of the dovetail groove, and after the tool bit has entered the dovetail groove, before performing the step of cutting a portion of the groove bottom of the dovetail groove, the tool bit is rotated around the first axis so that the blade width direction of the blade portion is substantially parallel to the width direction of the dovetail groove.

9. The method for machining a dovetail groove according to any one of claims 1 to 7, wherein the tool bit has a shaft that supports the cutting edge, and the distance between one end of the tip edge in the cutting width direction and the central axis of the shaft when viewed in the cutting thickness direction is greater than the distance between the other end of the tip edge in the cutting width direction and the central axis when viewed in the cutting thickness direction.

10. A method for machining a dovetail groove according to any one of claims 1 to 9, wherein a cycle comprising the steps of moving the blade along the extending direction of the dovetail groove while the tip edge is in contact with the bottom of the groove, and changing the position of the blade in the width direction of the dovetail groove, is defined as a first machining cycle, the direction in which the blade moves along the extending direction of the dovetail groove in the first machining cycle is defined as a first movement direction, the direction opposite to the first movement direction is defined as a second movement direction, and a cycle comprising the steps of moving the blade in the second movement direction while the tip edge is in contact with the bottom of the groove, and changing the position of the blade in the width direction of the dovetail groove, wherein each of the first machining cycle and the second machining cycle is performed multiple times.

11. A method for machining a dovetail groove according to claim 4, further comprising the steps of: forming the dovetail groove in a rough state using a roughing tool held on the spindle; and replacing the roughing tool held on the spindle with the tool holder to which the tool bit is attached using a tool changing device, wherein after the step of replacing the roughing tool held on the spindle with the tool holder to which the tool bit is attached, the step of inserting the tool bit into the dovetail groove in a rough state is performed.

12. The method for machining a dovetail groove according to claim 1, wherein the blade portion has a shape that widens on one side from the base portion toward the tip edge portion, and the tip edge portion of the blade portion has a wave shape having a plurality of peaks and a plurality of valleys.

13. A machine tool comprising: a machining head that holds a tool holder to which a tool bit having a cutting edge that widens from the base to the tip edge is attached; a workpiece support device that supports a workpiece; a moving device that moves the machining head relative to the workpiece support device; and a control device that controls the moving device, wherein the control device is capable of performing the following processes: inserting the tool bit into a rough-machined dovetail groove formed in the workpiece; cutting a portion of the groove bottom of the dovetail groove by moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove; changing the position of the tool bit in the width direction of the dovetail groove; and cutting another portion of the groove bottom by moving the tool bit along the extending direction of the dovetail groove while the tool bit is inserted into the dovetail groove after the position of the tool bit has been changed in the width direction of the dovetail groove.

14. A tool bit comprising a blade portion whose blade width increases from the base to the tip edge, and a shaft that supports the blade portion, wherein the tip edge of the blade portion has a plurality of apex portions that contact the bottom of the groove of a dovetail groove.

15. The tool bit according to claim 14, wherein the distance between one end of the tip edge in the blade width direction and the central axis of the shaft, when viewed in the blade thickness direction, is greater than the distance between the other end of the tip edge in the blade width direction and the central axis, when viewed in the blade thickness direction.

Images