JP7545912B2 - Cutting tools, tool holders and machine tools - Google Patents

Description

The present invention relates to a cutting tool, a tool holder, and a machine tool.

Conventionally, there is known a machine tool in which a tool spindle is provided on a tool table, and cutting, drilling, or milling is performed with a tool attached to the tool spindle. When a cutting tool is attached to the tool spindle, it is necessary to restrict (lock) the rotation of the tool spindle. For example, a fixed position indexing device for a tool spindle for a turning center described in Patent Document 1 changes the engagement state of the first to third coupling parts by raising and lowering an annular piston using a hydraulic cylinder, thereby locking or unlocking the tool spindle. When the tool spindle is locked, the first to third coupling parts bear the processing load applied to the cutting tool.

Patent No. 4127737

In the configuration described in Patent Document 1, as shown in FIG. 11, the central axis J of the tool spindle 150 and the cutting direction K of the cutting tool 170 into the workpiece W are the same. In this case, the principal component force Fa of the cutting resistance applied to the cutting tool 170 and the tool spindle 150 acts in a direction perpendicular to the central axis J of the tool spindle 150. In order to receive the principal component force Fa of the cutting resistance, the tool spindle 150 needs to stabilize the cutting tool during cutting by fixing the cutting tool with a strong force via a complex configuration including the first to third coupling parts and hydraulic cylinders. Therefore, for example, in the case of a configuration in which the force fixing the cutting tool is weak, or in the case of heavy cutting in which the cutting pressure of the cutting tool on the workpiece is high, it is difficult to stabilize the cutting tool during cutting.

The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a cutting tool, a tool holder, and a machine tool that can stabilize the cutting tool during cutting.

In order to achieve the above object, a cutting tool according to a first aspect of the present invention is a cutting tool fixedly supported by a tool holder attached to a tool spindle unit , configured to be able to cut into a workpiece in a cutting direction intersecting a longitudinal direction of the cutting tool , and equipped with a machining point that receives a principal component of cutting resistance in the longitudinal direction of the cutting tool from the workpiece rotating on its axis , and the cutting tool is supported by the tool holder such that the longitudinal direction of the cutting tool is parallel to a central axis of the tool holder, whereby the principal component of cutting resistance becomes a force pressing the tool holder against the tool spindle unit.

In order to achieve the above object, in a tool holder for holding the cutting tool according to a second aspect of the present invention, the principal force acts on a central axis of the tool holder toward the tool holder .

In order to achieve the above object, a tool holder for holding a cutting tool according to a third aspect of the present invention comprises a tool accommodating recess for accommodating the cutting tool, a tool holding member for holding the cutting tool in the tool accommodating recess , and a first fixing member for fixing the tool holding member to the tool holder, wherein a tool recess having a first inclined surface is formed on a side surface of the cutting tool, the tool accommodating recess extends in the longitudinal direction of the cutting tool and is formed on a side surface of the tool holder, and comprises a positioning surface with which a base end of the cutting tool opposite to the machining point comes into contact, thereby positioning the cutting tool in the longitudinal direction, and the tool holding member has a pressing portion having a second inclined surface opposing the first inclined surface, and when fitted into the tool recess, the tool holding member is pressed against the cutting tool by the first fixing member, thereby pressing the base end of the cutting tool against the positioning surface via the pressing portion .

In order to achieve the above object, a tool holder according to a fourth aspect of the present invention comprises a second fixing member that fixes a cutting tool in a direction perpendicular to a central axis of the tool holder .

In order to achieve the above-mentioned object, a machine tool according to a fifth aspect of the present invention includes the cutting tool, the tool holder, a work rotation unit that rotates the workpiece to cut the workpiece with the cutting tool, and a moving mechanism that moves the cutting tool relative to the workpiece so that the cutting tool receives a principal component of cutting resistance in the longitudinal direction of the rotating workpiece .

The present invention allows the cutting tool to be stabilized during cutting.

1 is a front view of a machine tool according to an embodiment of the present invention; 1 is a plan view of a machine tool according to an embodiment of the present invention; 1 is a cross-sectional view of a tool spindle unit to which a fixed tool unit according to an embodiment of the present invention is attached. FIG. 1 is a partial cross-sectional view of a tool spindle unit to which a rotary tool unit according to an embodiment of the present invention is attached. FIG. FIG. 2 is a bottom view of the tool spindle unit according to the embodiment of the present invention. FIG. 2 is a side view of the fixed tool unit according to the embodiment of the present invention. 7 is a cross-sectional view taken along line AA in FIG. 6. FIG. 2 is a front view of the fixed tool unit according to the embodiment of the present invention. FIG. 2 is a side view of the fixed tool unit according to the embodiment of the present invention. FIG. 2 is a perspective view of a tool holder, a coupling portion, and a spindle according to an embodiment of the present invention. FIG. 1 is a schematic diagram showing a manner in which a workpiece is machined by a cutting tool attached to a tool spindle according to the background art;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A cutting tool, a tool holder, a tool spindle unit, and a machine tool according to an embodiment of the present invention will be described below with reference to the drawings.
As shown in Figures 1 and 2, machine tool 1, which is a turning center, comprises a bed S, which is a base for the entire machine tool 1, a first spindle unit 10 having a first spindle 11, a second spindle unit 20 having a second spindle 21, a second spindle moving mechanism 25, a tool moving mechanism 42, a B-axis rotation mechanism 45, a tool spindle unit 50, a tool magazine 60, and a control unit 300.
In the following, the axial direction along the rotation axis of the first main shaft 11 and the second main shaft 21 is defined as the Z-axis direction, the height direction perpendicular to the Z-axis direction is defined as the X-axis direction, and the direction perpendicular to the X-axis and Z-axis directions is defined as the Y-axis direction.

The first spindle unit 10 grips and rotates the workpiece W. Specifically, the first spindle unit 10 includes a first spindle 11 and a first spindle stock 12 that rotatably supports the first spindle 11. The first spindle 11 grips one end of the workpiece W. A workpiece rotation motor (not shown) that rotates the first spindle 11 is built into the first spindle stock 12. The first spindle unit 10 is configured to be immovable relative to the bed S.

The second spindle unit 20 is provided at a position facing the first spindle unit 10 in the Z-axis direction. The second spindle unit 20 includes a second spindle 21 that grips the other end of the workpiece W, and a second spindle stock 22 that rotatably supports the second spindle 21. A workpiece rotation motor (not shown) that rotates the second spindle 21 is built into the second spindle stock 22.

The second spindle movement mechanism 25 includes a Y movement mechanism 25Y that moves the second spindle unit 20 in the Y-axis direction (Y2-axis direction) as shown in FIG. 2, an X movement mechanism 25X that moves the second spindle unit 20 in the X-axis direction (X2-axis direction) as shown in FIG. 1, and a Z movement mechanism 25Z that moves the second spindle unit 20 in the Z-axis direction (Z2-axis direction).

As shown in FIG. 2, the tool moving mechanism 42 includes a Y moving mechanism 42Y that moves the tool spindle unit 50 in the Y axis direction (Y1 axis direction), as shown in FIG. 1, an X moving mechanism 42X that moves the tool spindle unit 50 in the X axis direction (X1 axis direction), and a Z moving mechanism 42Z that moves the tool spindle unit 50 in the Z axis direction (Z1 axis direction).
As shown in FIG. 2, the slide table 25S, which moves in the Z-axis direction of the Z movement mechanism 25Z, and the slide table 42S, which moves in the Z-axis direction of the Z movement mechanism 42Z, move along a common rail 29 extending in the Z-axis direction on the bed S.

The X-moving mechanism 25X, 42X, the Y-moving mechanism 25Y, 42Y and the Z-moving mechanism 25Z, 42Z each have a motor, a ball screw and a nut, and are configured to convert the rotational force of the motor into linear motion by the ball screw and the nut, thereby enabling the corresponding second spindle unit 20 or tool spindle unit 50 to move linearly.
The B-axis rotation mechanism 45 rotates the tool spindle unit 50 in the B-axis direction. The B-axis direction is a rotation direction centered on a rotation axis along the Y-axis direction.

The tool magazine 60 holds a plurality of different types of tool units (for example, a fixed tool unit 70 and a rotating tool unit 80 ) and transfers the tool units to and from the tool spindle unit 50 .
In detail, the tool magazine 60 includes a tool support portion 61 and a drive portion 62 .
The tool support part 61 has a substantially annular shape and is supported rotatably about a rotation axis extending along the Z-axis direction. The tool support part 61 is formed with U-shaped tool gripping grooves that are located on the outer periphery of the tool support part 61 and open toward the radially outer side of the tool support part 61 so as to be aligned in the rotation direction of the tool support part 61.
The drive unit 62 has, for example, a motor, and rotates the tool support unit 61 about a rotation axis.

As shown in FIGS. 3 and 4 , the tool spindle unit 50 is, for example, a tool spindle, and is configured so that either a rotating tool unit 80 or a fixed tool unit 70 can be selectively attached thereto.
As shown in FIG. 3 , the tool spindle unit 50 includes a body 51 , a plurality of bearings 55 , a spindle 52 , a motor 53 , and a clamp mechanism 54 .
The body 51 includes a main body portion 51a and a coupling portion 51b.
The body main portion 51a has a cylindrical shape extending in a direction along the central axis J of the spindle 52. The body main portion 51a supports the spindle 52 rotatably via a plurality of bearings 55 in an internal space of the body main portion 51a.

The spindle 52 has a generally cylindrical shape and extends along a central axis J.
10, the spindle 52 has a plurality of protrusions 52a formed on the tip surface of the spindle 52. The protrusions 52a are rectangular parallelepipeds that protrude toward the tip side of the spindle 52, and are located closer to the tip side than the coupling portion 51b.
As shown in FIG. 5, the plurality of protrusions 52a (two in this example) are disposed at equal angular intervals (180° intervals in this example) in the circumferential direction C centered on the central axis J.
3, the spindle 52 has a holder accommodating portion 52b formed on the inner peripheral surface of the tip side of the spindle 52. The holder accommodating portion 52b is a hole having an inclined surface whose diameter increases toward the tip side of the spindle 52. The holder accommodating portion 52b accommodates a tapered portion 72 of a tool holder 71 (to be described later) of the fixed tool unit 70 or a tapered portion 82 of a tool holder 81 (to be described later) of the rotating tool unit 80 (see FIG. 4).

The motor 53 is provided on the outer periphery of the spindle 52 in the internal space of the body main portion 51a, and rotates the spindle 52 about the central axis J.
The coupling part 51b is fixed to the tip of the body main part 51a so as to close an opening on the tip side of the body main part 51a. The coupling part 51b is in the shape of a ring with a central axis J as its center.
10, a through hole 51h is formed in the center of the coupling portion 51b, extending along the central axis J. The tip of the spindle 52 passes through the through hole 51h.
The coupling portion 51b has a distal end surface formed with an annular protrusion 51c. The annular protrusion 51c is formed to surround the through hole 51h. The annular protrusion 51c has a plurality of fitting recesses 51d formed therein, into which fitting protrusions 74b (described later) of the fixed tool unit 70 are fitted.

Each fitting recess 51d has inclined surfaces 51f which are side surfaces on both sides in the circumferential direction C. The two inclined surfaces 51f of one fitting recess 51d are inclined such that the distance between the two inclined surfaces 51f becomes smaller as the fitting recess 51d approaches the bottom surface of the fitting recess 51d, i.e., as the fitting recess 51d approaches the coupling portion 51b.
5, the multiple fitting recesses 51d (four in this example) are disposed at equal angular intervals (90° intervals in this example) in the circumferential direction C centered on the central axis J. Each fitting recess 51d extends along the circumferential direction C.

As shown in FIGS. 3 and 4, the clamp mechanism 54 pulls the clamp portions 76, 86 into the spindle 52 to clamp it.
The clamp mechanism 54 includes a draw bar 54a, a piston 54b, a first spring 54d, a receiving portion 54e, a second spring 54f, a plurality of balls 54g, and an air supply portion 54h.

The drawbar 54a is cylindrical and extends along the central axis J, and is provided within the spindle 52 so as to be movable in a direction along the central axis J. A number of balls 54g are fitted into the tip of the drawbar 54a so as to be movable in the radial direction of the drawbar 54a. The balls 54g grip (clamp) or release (unclamp) the clamping portions 76, 86 depending on the position of the drawbar 54a.

The receiving portion 54 e is fixed to the rear end of the drawbar 54 a and protrudes rearward beyond the rear end of the spindle 52 .
The second spring 54f is provided on the outer periphery of the drawbar 54a within the spindle 52. The second spring 54f biases the receiving portion 54e together with the drawbar 54a toward the rear end side.
The piston 54b is located at the rear end side of the receiving portion 54e and is biased in a direction away from the receiving portion 54e by the elastic force of the first spring 54d. The air supply unit 54h supplies air to the air supply space 54m under the control of the control unit 300. As a result, when the pressure in the air supply space 54m increases, the piston 54b approaches the receiving portion 54e against the elastic force of the second spring 54f and presses the receiving portion 54e. Then, the receiving portion 54e moves to the tip side of the draw bar 54a together with the draw bar 54a and the ball 54g against the biasing force of the second spring 54f. Therefore, the ball 54g reaches the recess 52c formed on the inner peripheral surface at the tip side of the spindle 52. As a result, the force of the ball 54g pressing the clamping portions 76, 86 is released, and the fixed tool unit 70 or the rotating tool unit 80 is in an unclamped state in which it can be removed from the tool spindle unit 50.
When the air supply from the air supply unit 54h to the air supply space 54m is stopped, the piston 54b receives the biasing force from the first spring 54d and moves away from the receiving portion 54e. In this state, the draw bar 54a and the balls 54g are positioned at the rear end side by the biasing force of the second spring 54f. Therefore, the balls 54g sandwich the clamping portions 76, 86, and the fixed tool unit 70 or the rotating tool unit 80 is fixed to the tool spindle unit 50 in a clamped state.

Next, the fixed tool unit 70 will be described.
As shown in Fig. 3, the fixed tool unit 70 is fixedly supported by the tool spindle unit 50 so as not to rotate about its axis. The fixed tool unit 70 is, for example, a tool unit that performs cutting processing. As shown in Fig. 9, the tool spindle unit 50 is configured to be able to cut through the fixed tool unit 70 in a cutting direction K that is perpendicular to the central axis J of the fixed tool unit 70.

6 , the fixed tool unit 70 includes a cutting tool 73 that cuts a workpiece, and a tool holder 71 that holds the cutting tool 73. The cutting tool 73 is, for example, a cutting tool, and is configured to be detachable from the tool holder 71.
The cutting tool 73 includes a tool body 73a and a machining tip 73b attached to the tool body 73a.
The tool body 73 a has a prismatic shape extending along the central axis J of the fixed tool unit 70 .
7, the tool body 73a is formed with a tool recess 73c into which a tool holding member 79 (described later) fits. The tool recess 73c is located at an upper portion of a side surface extending along the central axis J of the tool body 73a, and extends along the width direction (Y-axis direction) of the tool body 73a perpendicular to the central axis J.

The tool recess 73c has a bottom surface 73c1, an orthogonal surface 73c2, and an inclined surface 73c3. The bottom surface 73c1 extends along the width direction of the tool body 73a. The orthogonal surface 73c2 is located at the end of the bottom surface 73c1 close to the machining tip 73b (see FIG. 6) and extends in a direction perpendicular to the bottom surface 73c1. The inclined surface 73c3 is located at the end of the bottom surface 73c1 far from the machining tip 73b and is inclined with respect to the bottom surface 73c1 so as to move away from the orthogonal surface 73c2 as it moves away from the bottom surface 73c1. The inclined surface 73c3 is formed so that the cutting tool 73 is pressed against the positioning surface 75b by the tool holding member 79 described later.

As shown in FIG. 6, the machining tip 73b is detachable from the tool body 73a and is used to cut the workpiece W. The machining tip 73b has a machining point 73d that cuts the workpiece W and is located in a direction perpendicular to the central axis J of the machining tip 73b. The machining point 73d is located on the central axis J of the fixed tool unit 70. The machining tip 73b is shaped like a diamond plate and is fixed to the tip surface of the tool body 73a.

As shown in FIG. 6, the tool holder 71 includes a tapered portion 72, a rotation regulating portion 74, a tool mounting portion 75, a clamp portion 76, a retained groove portion 78, a tool retaining member 79, and a plurality of first fixing members 77a. As shown in FIG. 8, the tool holder 71 includes a plurality of second fixing members 77b.
6, a base end portion of the cutting tool 73 opposite to the working tip 73b is attached to the tool attachment portion 75. The tool attachment portion 75 has a substantially semi-cylindrical shape extending along the central axis J.
The tool mounting portion 75 is formed with a tool accommodating recess 75a into which the base end of the cutting tool 73 fits and a holding member accommodating recess 75d into which the tool holding member 79 fits. The tool accommodating recess 75a and the holding member accommodating recess 75d are formed on a flat side surface 75F extending along the central axis J of the tool mounting portion 75.
As shown in Fig. 6 and Fig. 8, the second fixing members 77b are members for positioning the cutting tool 73 in the tool accommodating recess 75a in a direction perpendicular to the central axis J. The second fixing members 77b are bolts, and are arranged in a direction along the central axis J. Each second fixing member 77b extends along the cutting direction K while being screwed into a screw hole (not shown) formed in the tool mounting portion 75. The tip of the second fixing member 77b is configured to press the side surface of the cutting tool 73, as shown typically by the broken line in Fig. 6. Although not shown, a gap may be provided between the side surface of the cutting tool 73 pressed by the second fixing member 77b and the side surface of the tool accommodating recess 75a on which the screw hole is formed.

As shown in Fig. 8, the tool accommodating recess 75a is formed as a groove extending along the central axis J. The tip of the tool accommodating recess 75a is formed to the tip surface of the tool mounting portion 75. The tool accommodating recess 75a includes a positioning surface 75b located on the base end side of the tool accommodating recess 75a. The positioning surface 75b extends in a direction intersecting with the central axis J, in this example, in a direction perpendicular to the central axis J, and positions the cutting tool 73 in a direction along the central axis J by contacting the base end surface of the tool main body portion 73a. Although not shown, the width of the tool accommodating recess 75a in the short direction is formed to be larger than the width of the cutting tool 73 in the short direction.
The holding member accommodating recess 75d is formed so as to pass through the middle portion of the tool accommodating recess 75a and intersect with the tool accommodating recess 75a. The holding member accommodating recess 75d is formed as a groove that is shallower than the tool accommodating recess 75a.

As shown in FIG. 6, the tool mounting portion 75 has an inclined surface 75c formed so as to escape from the workpiece W gripped by the first spindle 11 (see FIG. 1). The inclined surface 75c is formed on the opposite side of the tool storage recess 75a with respect to the central axis J. The inclined surface 75c is located above the workpiece W being machined by the fixed tool unit 70. The inclined surface 75c inclines so as to move away from the workpiece W in the X-axis direction as it moves away from the cutting tool 73 in the Y-axis direction (cutting direction K).

The tool holding member 79 is a member that holds the cutting tool 73 in the tool accommodating recess 75a, and is fixed to the tool mounting portion 75 by the first fixing member 77a. The tool holding member 79 is housed in the holding member accommodating recess 75d when the cutting tool 73 is housed in the tool accommodating recess 75a. The tool holding member 79 is shaped like a rectangular column that extends along the width direction of the cutting tool 73 so as to cross and straddle the cutting tool 73 housed in the tool accommodating recess 75a.

7, the tool holding member 79 includes a pressing portion 79a which is an inclined surface facing the inclined surface 73c3 of the tool recess 73c. The pressing portion 79a of the tool holding member 79 is formed to cooperate with the inclined surface 73c3 of the tool recess 73c to press the tool body portion 73a against the positioning surface 75b.
6, the multiple first fixing members 77a are members that fix the tool holding member 79 to the tool mounting portion 75. The multiple first fixing members 77a are each a bolt, and are located at both longitudinal ends of the tool holding member 79. Each first fixing member 77a extends in a direction perpendicular to both the extension direction of the tool holding member 79 and the extension direction of the cutting tool 73.

The retained groove portion 78 is located between the tool mounting portion 75 and the rotation restricting portion 74 along the central axis J of the fixed tool unit 70, and is a disk shape with a groove formed around the entire outer periphery. The tool mounting portion 75 fits into the tool gripping groove of the tool support portion 61 (see FIG. 1) described above.

The rotation restricting portion 74 is fitted into the body 51 (see FIG. 3 ) so that the body 51 receives the machining load applied to the fixed tool unit 70 while restricting the rotation of the fixed tool unit 70. The rotation restricting portion 74 is located between the tapered portion 72 and the held groove portion 78 along the central axis J of the fixed tool unit 70.
As shown in FIG. 6, the rotation restricting portion 74 includes a disk portion 74a, a plurality of fitting protrusions 74b, and a plurality of grooves 74c.
The disk portion 74a is formed in a disk shape with the central axis J as its center.
10, the grooves 74c are formed in a concave shape on the outer circumferential side of the disk portion 74a. The grooves 74c open toward the outside in the radial direction of the disk portion 74a.
The plurality of grooves 74c (two in this example) are disposed at equal angular intervals, in this example at 180° intervals, in the circumferential direction C centered on the central axis J. The protrusion 52a of the spindle 52 fits into the grooves 74c.

As shown in FIG. 10, the multiple mating convex portions 74b fit into the multiple mating concave portions 51d of the coupling portion 51b, thereby enabling the body 51 to bear the machining load applied to the fixed tool unit 70 while restricting rotation of the fixed tool unit 70 relative to the coupling portion 51b.
The multiple fitting protrusions 74b are each located on the outer circumferential side of the rear surface of the disk portion 74a, extend in a direction along the central axis J and in the circumferential direction C, and are arranged along the circumferential direction C. The multiple fitting protrusions 74b, four in this example, are arranged at equal angular intervals, in this example, at 90° intervals.
Each fitting protrusion 74b has inclined surfaces 74b1 which are side surfaces located on both sides in the circumferential direction C. The two inclined surfaces 74b1 of one fitting protrusion 74b are inclined so as to approach each other as they move away from the disk portion 74a in the direction along the central axis J. In other words, the fitting protrusion 74b has a trapezoidal shape when viewed from a direction perpendicular to the central axis J.
The inclined surface 74b1 comes into surface contact in the circumferential direction C with the inclined surface 51f of the fitting recess 51d of the coupling portion 51b.

As shown in FIG. 6, the tapered portion 72 is located on the rear surface of the disk portion 74a, extends along the central axis J, and is formed as a truncated cone whose diameter decreases toward the rear end side.
As shown in Fig. 3, the tapered portion 72 is accommodated in the holder accommodation portion 52b of the spindle 52. A gap is formed between the outer peripheral surface of the tapered portion 72 and the inner peripheral surface of the holder accommodation portion 52b. Therefore, the tapered portion 72 of the fixed tool unit 70 and the holder accommodation portion 52b of the spindle 52 are not in contact with each other. In other words, as shown in Fig. 10, the fitting convex portion 74b and the fitting concave portion 51d are fitted together so as to form a gap.
6, the clamp portion 76 is fixed to the rear end surface of the tapered portion 72. The clamp portion 76 is columnar and extends along the central axis J. The clamp portion 76 is provided with a spherical portion 76a that is located at the rear end of the clamp portion 76 and on which the balls 54g are caught in the clamped state.

Next, the rotating tool unit 80 will be described.
As shown in FIG. 4 , the rotating tool unit 80 is supported by the tool spindle unit 50 so as to be rotatable together with the spindle 52 .
The rotating tool unit 80 includes a tool part 83 that processes a workpiece, and a tool holder 81 that holds the tool part 83. The tool part 83 is a rotating tool such as a drill.
The tool holder 81 comprises a tapered portion 82 similar to the tapered portion 72 described above, a tool mounting portion 85 similar to the tool mounting portion 75 described above, a clamp portion 86 similar to the clamp portion 76 described above, and a held groove portion 88 similar to the held groove portion 78 described above.
The rotating tool unit 80 will be described below, focusing on the differences from the fixed tool unit 70.
The tool holder 81 of the rotating tool unit 80 has a groove similar to the groove 74c into which the protrusion 52a of the spindle 52 fits, but does not have the fitting protrusion 74b, unlike the fixed tool unit 70. The protrusion 52a of the spindle 52 fits into the groove of the tool holder 81 of the rotating tool unit 80, whereby the rotation of the spindle 52 is transmitted to the rotating tool unit 80. In addition, with the tool holder 81 of the rotating tool unit 80 fitted onto the tip of the spindle 52, the outer peripheral surface of the tapered portion 82 of the rotating tool unit 80 and the inner peripheral surface of the holder accommodating portion 52b are in surface contact with each other.

As shown in FIG. 1, the control unit 300 controls the first spindle unit 10, the second spindle unit 20, the second spindle movement mechanism 25, the tool movement mechanism 42, the B-axis rotation mechanism 45, the tool spindle unit 50, and the tool magazine 60. The control unit 300 includes, for example, a CPU (Central Processing Unit) (not shown) and a ROM (Read Only Memory) that stores a program that defines the procedure of processing by the CPU.

Next, a description will be given of the machining process executed by the control unit 300. The control unit 300 executes this machining process in accordance with an NC program created in advance.
As shown in FIG. 1, the control unit 300 machines the workpiece W gripped by the first spindle 11 with the fixed tool unit 70 or the rotating tool unit 80 attached to the tool spindle unit 50. For example, when the fixed tool unit 70 is attached to the tool spindle unit 50, the control unit 300 cuts the outer peripheral surface of the workpiece W by feeding the cutting tool 73 of the fixed tool unit 70 in the Z-axis direction while cutting into the workpiece W via the tool moving mechanism 42, while rotating the first spindle 11 together with the workpiece W. At this time, as shown in FIG. 9, the cutting direction K of the cutting tool 73 is set in the Y-axis direction perpendicular to the central axis J of the fixed tool unit 70, and the principal component force Fa of the cutting resistance generated in the cutting tool 73 during cutting acts in the direction along the central axis J. In this example, the rotation axis of the workpiece W is located in the cutting direction K of the processing point 73d. In addition, since the processing point 73d of the processing tip 73b is provided on the central axis J, the principal component force Fa of the cutting resistance is located on the central axis J. This suppresses the generation of a rotational moment in the fixed tool unit 70 due to the principal component force Fa of the cutting resistance. The principal component force Fa of the cutting resistance serves as a force pressing the cutting tool 73 against the tool mounting portion 75 of the tool holder 71, and also serves as a force pressing the fitting convex portion 74b of the rotation restricting portion 74 of the tool holder 71 against the fitting concave portion 51d (see FIG. 10 ) of the coupling portion 51b of the tool spindle unit 50. As described above, regardless of the magnitude of the force clamping the fixed tool unit 70 by the tool spindle unit 50, it is possible to suppress the positional deviation of the machining point 73d due to the cutting resistance, thereby realizing stable heavy cutting and improving the machining quality of the workpiece W.

After the control unit 300 has completed machining of the workpiece W held by the first spindle 11, it moves the second spindle 21 to a position opposite the first spindle 11 via the second spindle moving mechanism 25, and transfers the workpiece W from the first spindle 11 to the second spindle 21. Then, the control unit 300 machines the workpiece W held by the second spindle 21 with a tool attached to a tool rest (not shown), and ejects the machined workpiece W to the outside. This completes the machining process.

Next, a description will be given of a method for mounting the cutting tool 73 to the tool holder 71. This mounting operation is performed, for example, by an operator.
First, as shown in Figs. 6 and 7, the cutting tool 73 is inserted into the tool housing recess 75a. Then, the second fixing members 77b are screwed into threaded holes (not shown) formed in the tool mounting portion 75, and the cutting tool 73 is lightly pressed toward the inner side surface of the tool housing recess 75a with the tip of each second fixing member 77b, thereby temporarily fixing the cutting tool 73. In this temporarily fixed state, the side surface of the cutting tool 73 is in contact with the inner side surface of the tool housing recess 75a. Next, the tool holding member 79 is inserted into the holding member housing recess 75d. Then, the threaded shaft portion of each first fixing member 77a is passed through a shaft through hole (not shown) formed in the tool holding member 79, and screwed into a threaded hole (not shown) formed in the bottom surface of the tool housing recess 75a. As a result, the head of each first fixing member 77a presses the tool holding member 79 toward the cutting tool 73 from the surface of the tool holding member 79 (the surface opposite to the surface facing the cutting tool 73). At this time, the tool holding member 79 is pressed toward the bottom surface 73c1 of the tool recess 73c by the first fixing members 77a, as shown by arrow F1 in Fig. 7. As a result, the pressing portion 79a of the tool holding member 79 slides against the inclined surface 73c3 of the tool recess 73c, and presses the tool body portion 73a toward the positioning surface 75b of the tool accommodating recess 75a, as shown by arrow F2 in Fig. 7. At this time, the cutting tool 73 is temporarily fixed by the second fixing members 77b, and is therefore movable toward the positioning surface 75b.
Finally, the second fixing members 77b are firmly tightened to bring the side surface of the cutting tool 73 into intimate contact with the inner surface of the tool accommodating recess 75a.
With the above, the mounting of the cutting tool 73 to the tool holder 71 is completed.

Next, a description will be given of a process executed by the control unit 300 when changing the type of the tool unit attached to the tool spindle unit 50. In the following, an example will be described in which the rotating tool unit 80 attached to the tool spindle unit 50 is changed to the fixed tool unit 70.
The control unit 300 moves the tool spindle unit 50 via the tool moving mechanism 42 and the B-axis rotating mechanism 45 so that the rotating tool unit 80 mounted on the tool spindle unit 50 fits into the tool gripping groove of the tool magazine 60. Then, the control unit 300 switches the clamping mechanism 54 from the clamped state to the unclamped state, and moves the tool spindle unit 50 in the Z-axis direction away from the tool magazine 60 via the tool moving mechanism 42, thereby removing the rotating tool unit 80 from the tool spindle unit 50. Next, the control unit 300 rotates the tool magazine 60 to perform an indexing operation of the fixed tool unit 70 supported by the tool magazine 60, thereby causing the tool spindle unit 50 to face the fixed tool unit 70 in the Z-axis direction, and inserts the clamping portion 76 of the fixed tool unit 70 into the tip side of the draw bar 54a. Then, the control unit 300 switches the clamping mechanism 54 from the unclamped state to the clamped state. This completes the mounting of the fixed tool unit 70 to the tool spindle unit 50. Thereafter, as described above, the workpiece W is machined by the fixed tool unit 70 attached to the tool spindle unit 50 .

(effect)
According to the embodiment described above, the following effects are achieved.
(1) The cutting tool 73 is fixedly supported by the tool holder 71. The cutting tool 73 includes a processing point 73d configured to be able to cut into the workpiece W in a cutting direction K that intersects with the longitudinal direction of the cutting tool 73 (the direction along the central axis J).
According to this configuration, the principal component force Fa of the cutting resistance applied to the cutting tool 73 during cutting acts in a direction along the central axis J, so that the cutting tool 73 can be stabilized during cutting.
Furthermore, in the above configuration, even if the tool spindle unit 50 has a simple configuration in which the force for fixing the tool holder 71 is weak, the cutting tool 73 can be stabilized during cutting.
Furthermore, even in the case of heavy cutting, the cutting tool 73 can be stabilized during cutting.

(2) The tool holder 71 that holds the cutting tool 73 has the tool accommodating recess 75 a, which is an example of a tool accommodating portion that accommodates the cutting tool 73 so that the machining point 73 d is positioned on the central axis J of the tool holder 71.
According to this configuration, the generation of a rotational moment in the tool holder 71 due to the principal component force Fa of the cutting resistance is suppressed, and the cutting tool 73 can be stabilized during cutting.

(3) The tool holder 71 that holds the cutting tool 73 includes a tool accommodating recess 75a that accommodates the cutting tool 73, and a tool holding member 79 that holds the cutting tool 73 in the tool accommodating recess 75a. The tool accommodating recess 75a includes a positioning surface 75b that positions the cutting tool 73 in a direction along the central axis J by contacting a base end of the cutting tool 73 on the side opposite to the machining point 73d. The tool holding member 79 includes a pressing portion 79a that presses the base end of the cutting tool 73 against the positioning surface 75b.
According to this configuration, the cutting tool 73 is positioned in a direction along the central axis J, so that cutting of the workpiece W can be performed with higher precision.

(4) The tool spindle unit 50 can selectively mount either the fixed tool unit 70 having the cutting tool 73 and the tool holder 71 or the rotating tool unit 80, supports the rotating tool unit 80 rotatably about the central axis J, and fixedly supports the fixed tool unit 70.
According to this configuration, with the fixed tool unit 70 attached, the tool spindle unit 50 can stabilize the cutting tool 73 during cutting, as described above.

(5) The machine tool 1 includes a cutting tool 73, a tool holder 71, a first spindle 11 which is an example of a work rotation part that rotates the workpiece W to cut the workpiece W with the cutting tool 73, and a tool moving mechanism 42 which is an example of a moving mechanism that moves a machining point 73d relative to the workpiece W in a cutting direction K along the radial direction of the workpiece W supported by the first spindle 11.
According to this configuration, in the machine tool 1, the cutting tool 73 can be stabilized during cutting, as described above.

Note that this disclosure is not limited to the above-described embodiments and drawings. Modifications (including the deletion of components) may be made as appropriate within the scope of the present disclosure without changing its gist. An example of a modification is described below.

(Modification)
In the above embodiment, the tool spindle unit 50 is applied to a turning center, but it is not limited to a turning center as long as it is a machine tool, and may be applied to, for example, a machining center. This machining center machines a workpiece by rotating a table to which the workpiece is fixed, with the fixed tool unit 70 attached to the tool spindle unit 50.

In the above embodiment, the machine tool 1 is provided with the first spindle unit 10 and the second spindle unit 20, but either one of the first spindle unit 10 and the second spindle unit 20 may be omitted.
The configuration in which the tool spindle unit 50 restricts the rotation of the fixed tool unit 70 in the above embodiment is not limited to the engagement between the mating convex portion and the mating concave portion, and can be modified as appropriate.

The movement directions of the first spindle unit 10, the second spindle unit 20, and the tool spindle unit 50 in the above embodiment can be changed as appropriate. For example, the first spindle unit 10 may be configured to be movable in the Z-axis direction.

In the above embodiment, the motor 53 , which is an example of a drive source, is provided inside the body 51 , but this is not limiting and the motor 53 may be provided outside the body 51 .
The pressing portion 79a of the tool holding member 79 and the inclined surface 73c3 of the tool recess 73c may be omitted.
In the above embodiment, the principal component force Fa of the cutting resistance is located on the central axis J of the tool spindle unit 50. However, it may be located away from the central axis J.
In the above embodiment, the cutting direction K is perpendicular to the central axis J. However, the cutting direction K is not limited to being perpendicular, and may be any direction as long as it intersects with the central axis J.
In the above embodiment, the processed tip 73b has a rhombic plate shape, but this is not limited thereto and may have another shape, for example, a triangular plate shape.

In the above embodiment, the cutting tool 73 is fixedly supported by the tool spindle unit 50 via the tool holder 71, but this is not limited thereto, and the tool spindle unit 50 may be omitted and the tool holder 71 may be fixed to the slide table of the tool movement mechanism 42. In this case, the tool holder 71 may be, for example, a comb tool rest that holds multiple cutting tools 73. Also, this is not limited thereto, and the cutting tool 73 or the tool holder 71 may be configured to be held on a turret tool rest. Even in these modified examples, the cutting tool 73 is configured to be able to cut into the workpiece W in the cutting direction K that intersects with its longitudinal direction, so that the cutting tool 73 can be stabilized during cutting as described above.

1...machine tool, 10...first spindle unit, 11...first spindle, 12...first spindle stock, 20...second spindle unit, 21...second spindle, 22...second spindle stock, 25...second spindle movement mechanism, 25S, 42S...slide table, 25X, 42X...X movement mechanism, 25Y, 42Y...Y movement mechanism, 25Z, 42Z...Z movement mechanism, 29...rail, 42...tool movement mechanism, 45...B-axis rotation mechanism, 50...tool spindle unit, 51...body, 51a...body main Body portion, 51b...coupling portion, 51c...annular convex portion, 51d...fitting concave portion, 51f, 73c3, 74b1, 75c...inclined surface, 51h...through hole, 52...spindle, 52a...convex portion, 52b...holder accommodating portion, 52c...concave portion, 53...motor, 54...clamp mechanism, 54a...draw bar, 54b...piston, 54d...first spring, 54f...second spring, 54e...receiving portion, 54g...ball, 54h...air supply portion, 54m...air supply space, 55...bearing, 60...tool magazine, 61...tool support portion, 62...drive portion, 70...fixed tool unit, 71, 81...tool holder, 72, 82...tapered portion, 73, 170...cutting tool, 73a...tool body portion, 73b...machining tip, 73c...tool recess, 73c1...bottom surface, 73d...machining point, 73c2...orthogonal surface, 74...rotation restriction portion, 74a...disk portion, 74b...fitting convex portion, 74c...groove portion, 75, 85...tool mounting portion, 75F...flat side surface, 75a...tool accommodating recess, 75b...positioning surface, 75d...holding member accommodating recess, 76, 86...clamping portion, 76a...spherical portion, 77a...first fixing member, 77b...second fixing member, 78, 88...held groove portion, 79...tool holding member, 79a...pressing portion, 80...rotating tool unit, 83...tool portion, 150...tool spindle, 300...control portion, C...circumferential direction, J...center axis, K...cutting direction, S...bed, W...workpiece, Fa...principal force

Claims (5)

A cutting tool fixedly supported by a tool holder attached to a tool spindle unit ,
The cutting tool is configured to be able to cut into a workpiece in a cutting direction intersecting a longitudinal direction of the cutting tool, and includes a processing point that receives a principal component force of cutting resistance from the workpiece rotating around an axis in the longitudinal direction of the cutting tool ,
the cutting tool is supported by the tool holder such that a longitudinal direction of the cutting tool is parallel to a direction of a central axis of the tool holder, and thereby a principal component force of cutting resistance becomes a force pressing the tool holder against the tool spindle unit.
Cutting tools. A tool holder for holding the cutting tool according to claim 1,
the principal force acts on a central axis of the tool holder toward the tool holder ;
Tool holder. A tool holder for holding the cutting tool according to claim 1,
a tool accommodating recess that accommodates the cutting tool;
a tool holding member that holds the cutting tool in the tool accommodating recess ;
a first fixing member that fixes the tool holding member to the tool holder,
A tool recess having a first inclined surface is formed on a side surface of the cutting tool,
The tool accommodating recess is
a positioning surface extending in a longitudinal direction of the cutting tool, formed on a side surface of the tool holder, and contacting a base end of the cutting tool on an opposite side to the machining point to position the cutting tool in the longitudinal direction;
The tool holding member is
a pressing portion having a second inclined surface opposed to the first inclined surface, and the pressing portion is pressed against the cutting tool by the first fixing member in a state where the cutting tool is fitted into the tool recess, thereby pressing the base end of the cutting tool against the positioning surface via the pressing portion ;
Tool holder. The tool holder according to claim 3 further includes a second fixing member that fixes a cutting tool in a direction perpendicular to a central axis of the tool holder .
Tool holder . A cutting tool according to claim 1 ;
The tool holder;
a workpiece rotating unit that rotates the workpiece in order to cut the workpiece with the cutting tool;
a moving mechanism for moving the cutting tool relative to the workpiece so that the cutting tool receives a principal component force of cutting resistance from the rotating workpiece in a longitudinal direction of the cutting tool ,
Machine tools.

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