JP7637032B2 - Tool holders and machine tools - Google Patents

Description

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

For example, the tool spindle device with fixed position indexing function described in Patent Document 1 has multiple tools attached to a tool holder, and one of the multiple tools is indexed to a fixed position for use in machining.

JP 2000-126909 A

In the configuration described in Patent Document 1, when changing the tool to be used for machining among the multiple tools attached to the tool holder, it is necessary to rotate the tool holder and index the tool to be used to a fixed position.

The present invention was made in consideration of the above situation, and aims to provide a tool holder and machine tool that can change the cutting bit used for machining without the need for indexing.

In order to achieve the above-mentioned object, a tool holder according to a first aspect of the present invention is a tool holder mounted on a tool spindle unit, the tool holder comprising: a first tool holding part which holds a first cutting bit having a cutting edge facing in a facing direction to a workpiece held by the spindle and which has a first side surface positioned facing in the facing direction to a workpiece to be cut by the first cutting bit; and a second tool holding part which holds a second cutting bit having a cutting edge facing in the facing direction to a workpiece to be cut by the second cutting bit, the cutting edges of the first cutting bit and the second cutting bit being spaced apart in an axial direction along a central axis of the tool holder and being spaced apart in a direction perpendicular to the axial direction and parallel to the facing direction , the first side surface and the second side surface being aligned in the axial direction and formed at different heights from each other in the facing direction .

To achieve the above object, the machine tool according to the second aspect of the present invention comprises the tool holder, the tool spindle unit to which the tool holder is attached, the spindle, and a tool spindle movement mechanism that moves the tool spindle unit so that the cutting edge of the cutting bit cuts into a workpiece held by the spindle.

According to the present invention, the cutting bit used for processing can be changed without the need for indexing.

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 side view of a machine tool according to an embodiment of the present invention; FIG. 2 is a side view of a tool spindle unit according to an embodiment of the present invention. 1A is a front view of a fixed tool unit according to an embodiment of the present invention, FIG. 1B is a side view of the fixed tool unit, and FIG. FIG. 1 is a perspective view of a fixed tool unit according to an embodiment of the present invention. 1 is a cross-sectional view of a tool spindle unit to which a rotating tool unit according to an embodiment of the present invention is attached. FIG. 5A and 5B are front views of a fixed tool unit during machining according to an embodiment of the present invention. FIG. 2 is a perspective view of a tool holder and a body according to an embodiment of the present invention. FIG. 11 is a front view of a fixed tool unit according to a modified example of the present invention. 1A is a front view of a fixed tool unit according to a modified example of the present invention, FIG. 1B is a side view of the fixed tool unit, and FIG. 1C is a bottom view of the fixed tool unit.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A tool holder and a machine tool according to an embodiment of the present invention will now be described 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 fixed tool rest 30, a tool spindle unit 50, a tool spindle moving mechanism 42, a tool rotating mechanism 45, a support member 13, 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 depth direction perpendicular to the X-axis and Z-axis directions is defined as the Y-axis direction.

The first spindle unit 10 holds and rotates a 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 holds one end of the workpiece W. A workpiece rotating 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.
In this example, as shown in FIG. 3, the support member 13 is placed on the upper surface of the bed S and supports the first headstock 12 from the side so that the first spindle unit 10 is separated from the bed S in the X-axis direction.

As shown in Figures 1 and 2, 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 holds 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. 3, the tool spindle movement mechanism 42 includes a Y movement mechanism 42Y that moves the tool spindle unit 50 in the Y-axis direction (Y1-axis direction), an X movement mechanism 42X that moves the tool spindle unit 50 in the X-axis direction (X1-axis direction), and a Z movement mechanism 42Z that moves the tool spindle unit 50 in the Z-axis direction (Z1-axis direction).

The X-movement mechanism 25X, 42X, the Y-movement mechanism 25Y, 42Y, and the Z-movement 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 using the ball screw and the nut, thereby moving the corresponding second spindle unit 20 or tool spindle unit 50 linearly.

As shown in FIG. 1, the tool rotation mechanism 45 rotates the tool spindle unit 50 to rotate the tool units 70 and 80 attached to the tool spindle unit 50 in the B-axis direction. The B-axis direction is the direction of rotation about a rotation axis along the Y-axis direction.

The tool magazine 60 accommodates a plurality of tool units 70, 80 of different types, and delivers the tool units 70, 80 to and from the tool spindle unit 50. The tool magazine 60 is located above the first headstock 12. The tool magazine 60 is supported by a support member 13.
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 C extending along the Z-axis direction. As shown in Fig. 3, the tool support part 61 includes a plurality of tool gripping parts 61a. The plurality of tool gripping parts 61a are located on the outer periphery of the tool support part 61 and are arranged to line up in the rotation direction of the tool support part 61. Each tool gripping part 61a has a U-shaped groove that opens toward the radial outside of the tool support part 61, and holds the tool units 70, 80 by fitting the tool units 70, 80 into the groove. The tool gripping part 61a holds the tool units 70, 80 in an orientation along the Z-axis direction.
The driving unit 62 has, for example, a motor, and rotates the tool support unit 61 about the rotation axis C. The driving unit 62 is fixed to the support member 13.

1 and 2, the fixed tool rest 30 is configured to be able to mount a plurality of tools 35 for machining the workpiece W held by the second spindle 21. The plurality of tools 35 can be attached to the fixed tool rest 30 so as to be aligned in the X-axis direction and the Y-axis direction, respectively. The fixed tool rest 30 is installed on the upper surface of the bed S, and is provided at a height that allows the second spindle unit 20 to pass above.
The multiple tools 35 include rotating tools such as drills or end mills that rotate to machine the workpiece W, and fixed tools. The tools 35 are attached to the fixed tool rest 30 in a state of extending along the Z-axis direction. The fixed tool rest 30 includes a drive unit 31 (see FIG. 2 ) and a gear train (not shown) that transmits the driving force of the drive unit 31 as a rotational force to the tools 35 (rotating tools).
A workpiece discharge section (not shown), such as a workpiece conveyor, an unloader, or a chute box, is provided near the fixed tool rest 30 .

1, the tool spindle unit 50 is, for example, a tool spindle, and is configured to be able to mount a fixed tool unit 70 or a rotating tool unit 80. The tool spindle unit 50 fixedly supports the fixed tool unit 70 so that it cannot rotate about its axis, and supports the rotating tool unit 80 so that it can rotate about its axis. The fixed tool unit 70 is, for example, a turning tool, and the rotating tool unit 80 is, for example, a milling tool.
The tool spindle unit 50 machines the workpiece W held by the first spindle 11 or the workpiece W held by the second spindle 21 using the attached fixed tool unit 70 or rotary tool unit 80 .

As shown in FIG. 7 , the tool spindle unit 50 includes a body 51 , a spindle 52 , and a clamp mechanism 54 .
The body 51 is box-shaped and rotatably supports the spindle 52 in an internal space with the tip of the spindle 52 exposed to the outside.
The spindle 52 is cylindrical and axially rotatable by a motor (not shown). Tapered portions 72, 82 (described later) of the tool units 70, 80 can be attached to the tip of the spindle 52. The inner peripheral surface of the tip of the spindle 52 is formed as a tapered surface so as to fit along the outer peripheral surfaces of the tapered portions 72, 82 of the tool units 70, 80.
The clamp mechanism 54 pulls in clamp portions 76, 86 of the tool units 70, 80 (described later) into the spindle 52 to clamp them. The clamp mechanism 54 includes a draw bar 54a and a plurality of balls 54b. The draw bar 54a is cylindrical and located inside the spindle 52, and is configured to be movable forward and backward in a direction along the central axis I of the tool units 70, 80 by a driving unit such as an air cylinder. The plurality of balls 54b are fitted into the draw bar 54a so as to move together with the draw bar 54a. When the draw bar 54a is in the forward position, the balls 54b are located in recesses 52b on the inner peripheral surface of the spindle 52, and the clamp portions 76, 86 are released from the clamp mechanism 54 (unclamped state). When the drawbar 54a moves from the forward position to the backward position, the ball 54b gets caught by the spherical portions 76a, 86a located at the rear ends of the clamp portions 76, 86, and pulls in the clamp portions 76, 86. This causes the ball 54b to move out of the recess 52b. Then, the ball 54b is pressed toward the clamp portions 76, 86 by the inner peripheral surface of the spindle 52, and the clamp portions 76, 86 are gripped by the clamp mechanism 54 (clamped state).
As described above, the clamp mechanism 54 is capable of switching the states of the clamp portions 76, 86 between the unclamped state and the clamped state.

Next, the fixed tool unit 70 will be described with reference to Figures 5(a), 5(b), 5(c) and 6. In the following, the axial direction along the central axis I of the fixed tool unit 70 is defined as a first direction N1, and directions perpendicular to the first direction N1 are defined as a second direction N2 and a third direction N3. The second direction N2 and the third direction N3 are perpendicular to each other.
The fixed tool unit 70 is arranged so that the cutting bits 73a to 73d are oriented in the same direction and the cutting edges 73a1 to 73d1 are spaced apart from each other in the first direction N1, the second direction N2, and the third direction N3, so that the cutting bits to be used for machining can be changed among the cutting bits 73a to 73d without being rotated when attached to the tool spindle unit 50.
In detail, the fixed tool unit 70 includes a plurality of cutting bits 73 a to 73 d for machining the workpiece W, a tool holder 71 for holding the plurality of cutting bits 73 a to 73 d, and a plurality of set screws 78 .

As shown in Figures 5(a), (b), and (c), the tool holder 71 includes a tapered portion 72, a rotation regulating portion 74, tool holding portions 75a, 75b, a holding end portion 75c, a clamp portion 76, and a held groove portion 79.
The held groove portion 79 is located between the tool holding portions 75a, 75b and the rotation restricting portion 74 in the first direction N1, and has a disk shape with a groove formed around the entire outer circumferential surface. The held groove portion 79 fits into the tool gripping portion 61a of the tool magazine 60 (see FIG. 3).

The rotation restricting portion 74 is located between the tapered portion 72 and the held groove portion 79 in the first direction N1. As shown in Fig. 9, the rotation restricting portion 74 is formed to engage with the body 51 so as to cause the body 51 to receive a machining load applied to the fixed tool unit 70 while restricting the rotation of the fixed tool unit 70. In detail, the rotation restricting portion 74 includes a disk portion 74a, a plurality of engaging protrusions 74b, and a plurality of grooves 74c.
The disk portion 74a is formed in a disk shape with the central axis I as its center.
The grooves 74c are formed in a concave shape on the outer periphery of the disk portion 74a. The grooves 74c open radially outward of the disk portion 74a. The protrusion 52a on the tip side of the spindle 52 fits into the grooves 74c.
The multiple fitting protrusions 74 b fit into the multiple fitting recesses 51 d of the coupling portion 51 b of the body 51 .

As shown in Figures 5(a), (b), (c) and 6, the cutting bits 73a to 73d have a machining chip and a rectangular chip holder that holds the machining chip. The cutting bits 73a to 73d are held in the tool holder 71 in the same orientation. The length of the cutting bits 73a and 73b in the second direction N2 is longer than the length of the cutting bits 73c and 73d in the second direction N2.

The cutting bits 73a to 73d have cutting edges 73a1 to 73d1, respectively. The cutting edge 73a1 of the cutting bit 73a and the cutting edge 73b1 of the cutting bit 73b are spaced apart from each other in the third direction N3. The cutting edge 73c1 of the cutting bit 73c and the cutting edge 73d1 of the cutting bit 73d are spaced apart from each other in the third direction N3.
The cutting edges 73a1 and 73b1 are located farther from the central axis I in the second direction N2 than the cutting edges 73c1 and 73d1. The cutting edge 73a1 is aligned with the cutting edge 73c1 in the first direction N1, and the cutting edge 73b1 is aligned with the cutting edge 73d1 in the first direction N1.
The cutting bits 73a and 73c are used when cutting the workpiece W held by the first spindle 11. The cutting bits 73b and 73d are used when cutting the workpiece W held by the second spindle 21.

As shown in FIGS. 5(a), 5(b), 5(c) and 6, the tool holder 75a holds the cutting bits 73a and 73b, and the tool holder 75b holds the cutting bits 73c and 73d.
The tool holding portions 75a, 75b each have a T-shape when viewed from the second direction N2, and are arranged so as to be connected to each other in the first direction N1. The tool holding portion 75a is located closer to the rotation restricting portion 74 than the tool holding portion 75b, and is formed to be taller in the second direction N2 than the tool holding portion 75b.
The tool holding portion 75a has a first side surface 75a1 that faces the workpiece W when the workpiece W is machined by the cutting bits 73a and 73b. The tool holding portion 75b has a second side surface 75b1 that faces the workpiece W when the workpiece W is machined by the cutting bits 73c and 73d. The first side surface 75a1 and the second side surface 75b1 are formed as planes along the first direction N1 and the third direction N3, respectively. The first side surface 75a1 is formed higher than the second side surface 75b1 in the second direction N2. A step is formed between the first side surface 75a1 and the second side surface 75b1. The surfaces of the tool holding portions 75a and 75b opposite to the first side surface 75a1 and the second side surface 75b1 are formed in the same plane.

6, the tool holding portion 75a has accommodation recesses 75d, 75e for accommodating the cutting bits 73a, 73b between the tool holding portion 75b and the tool holding portion 75a. The accommodation recesses 75d, 75e are located on both sides of the tool holding portion 75a in the third direction N3, extend along the second direction N2, and are formed in a concave shape that opens toward both outsides in the third direction N3.
The tool holding portion 75b has accommodation recesses 75f, 75g for accommodating the cutting bits 73c, 73d between the tool holding portion 75b and the holding end portion 75c. The accommodation recesses 75f, 75g are located on both sides of the tool holding portion 75b in the third direction N3, extend along the second direction N2, and are formed in a concave shape that opens toward both outsides in the third direction N3.

The holding end 75c is plate-shaped and extends along the third direction N3, and is located at the end of the tool holding portion 75b opposite the tool holding portion 75a. The holding end 75c is formed to be lower in height in the second direction N2 than the tool holding portion 75b. The tool holder 71 is formed in a three-step staircase shape consisting of the tool holding portion 75a, the tool holding portion 75b, and the holding end 75c.

5(a) and 5(b), the plurality of set screws 78 fix the cutting bits 73a to 73d in the accommodation recesses 75d to 75g. The set screws 78 are, for example, flat-tip set screws. Two set screws 78 are provided for each of the plurality of cutting bits 73a to 73d, and the two set screws 78 are aligned in the longitudinal direction of each of the cutting bits 73a to 73d, i.e., in the second direction N2.
The tool holding portion 75b is formed with screw holes 75i into which a plurality of set screws 78 are screwed. The screw holes 75i are formed to penetrate a base portion of the tool holding portion 75b extending along the second direction N2 and the third direction N3, and are formed to communicate between the accommodating recesses 75d and 75f and between the accommodating recesses 75e and 75g.
The holding end 75c is formed with screw holes 75h into which a plurality of set screws 78 are screwed, and screw passing holes 75k through which the set screws 78 can pass. The screw holes 75h penetrate the holding end 75c in the thickness direction. The screw passing hole 75k is formed between the two screw holes 75h and at a position facing the screw holes 75i of the tool holding portion 75b in the first direction N1. The screw passing hole 75k is formed so that the set screws 78 and the tool can pass through when the set screws 78 are screwed into the screw holes 75i.

Next, a description will be given of an operation for attaching the cutting tools 73a to 73d to the tool holder 71. This operation is performed, for example, by an operator.
First, with none of the cutting bits 73a to 73d attached to the tool holder 71, the cutting bits 73a and 73b are accommodated in the accommodation recesses 75d and 75e of the tool holder 71. At this time, the cutting edges 73a1 and 73b1 of the cutting bits 73a and 73b are caused to protrude beyond the first side surface 75a1 of the tool holding portion 75a. Then, the set screws 78 are screwed into the respective screw holes 75i from within the accommodation recesses 75f and 75g, so that the tip portions of the set screws 78 are pressed against the side surfaces of the cutting bits 73a and 73b. This fixes the cutting bits 73a and 73b in the accommodation recesses 75d and 75e.
Next, the cutting bits 73c, 73d are accommodated in the accommodation recesses 75f, 75g of the tool holder 71. At this time, the cutting edges 73c1, 73d1 of the cutting bits 73c, 73d are caused to protrude beyond the second side surface 75b1 of the tool holding portion 75b. Then, the set screws 78 are screwed into the respective screw holes 75h from the outside of the holding end portion 75c, so that the tip portions of the set screws 78 are pressed against the side surfaces of the cutting bits 73c, 73d. This fixes the cutting bits 73c, 73d in the accommodation recesses 75f, 75g.
With the above, the operation of attaching the cutting tools 73a to 73d to the tool holder 71 is completed.
The cutting bits 73a to 73d can be removed from the tool holder 71 by reversing the procedure for attaching the cutting bits 73a to 73d to the tool holder 71. When the tip at the tip of the cutting bits 73a to 73d is broken or worn out, only the tip is replaced. The type of cutting bit can be changed by removing the cutting bit and then attaching a new cutting bit.

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 fixed tool rest 30, the tool spindle unit 50, the tool spindle movement mechanism 42, the tool rotation mechanism 45, and the tool magazine 60. The control unit 300 includes, for example, a processing unit such as a CPU (Central Processing Unit) (not shown), and a memory such as a ROM (Read Only Memory) that stores a program that defines the processing procedures to be performed by this processing unit.

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 (Numerical Control) program created in advance.
As shown in FIG. 1, the control unit 300 supplies a workpiece W from the rear of the first spindle unit 10 using a workpiece supply unit (not shown).
Then, the control unit 300 performs a first machining process on the workpiece W held by the first spindle 11 using the fixed tool unit 70 or the rotating tool unit 80 attached to the tool spindle unit 50.

Hereinafter, as the first machining, a case where turning is performed in sequence by the two cutting bits 73a, 73c of the fixed tool unit 70 attached to the tool spindle unit 50 will be described.
First, as shown in Fig. 4, the control unit 300 rotates the tool spindle unit 50 in the B-axis direction via the tool turning mechanism 45 so that the central axis I of the fixed tool unit 70 is aligned with the X-axis direction. Then, as shown in Fig. 8(a), the control unit 300 feeds the cutting bit 73a in the Z-axis direction together with the tool spindle unit 50 while rotating the first spindle 11 together with the workpiece W at a position where the cutting edge 73a1 of the cutting bit 73a of the fixed tool unit 70 cuts into the outer circumferential surface of the workpiece W held by the first spindle 11 via the tool spindle moving mechanism 42. As a result, the workpiece W is cut by the cutting bit 73a. The machining width of the workpiece W in the Z-axis direction by the cutting bit 73a is set to be smaller than the distance between the two cutting edges 73a1 and 73b1 (see Fig. 6). When this cutting is completed, the control unit 300 moves the tool spindle unit 50 via the tool spindle moving mechanism 42 to a position where the cutting edge 73c1 of the cutting bit 73c can cut into the outer circumferential surface of the workpiece W, as shown in Fig. 8(b). Then, while rotating the first spindle 11 together with the workpiece W, the cutting bit 73c is fed in the Z-axis direction together with the tool spindle unit 50 via the tool spindle moving mechanism 42. This causes the cutting of the workpiece W by the cutting bit 73c. The machining width of the workpiece W in the Z-axis direction by the cutting bit 73c is set to be smaller than the distance between the two cutting edges 73c1, 73d1 (see Fig. 6).
In this way, when switching the tool used for machining between the cutting bits 73 a, 73 c, it is sufficient to move the tool spindle unit 50 linearly; there is no need for the tool spindle unit 50 to set the rotational position of the fixed tool unit 70, i.e., there is no need to index the tool spindle unit 50.
The order of machining by the cutting tools 73a and 73c may be reversed.

In addition, in this first machining, for example, if a rotating tool unit 80 is attached to the tool spindle unit 50, milling may be performed by rotating the cutting edge 81 (see FIG. 7) of the rotating tool unit 80 and bringing it into contact with the workpiece W.

Next, as shown in Figures 1 and 2, when the first machining is completed, the control unit 300 moves the second spindle 21 via the second spindle moving mechanism 25 to a position opposite the first spindle 11, and transfers the workpiece W from the first spindle 11 to the second spindle 21.
Then, the control unit 300 performs a second machining process on the workpiece W held by the second spindle 21 using the tool 35 attached to the fixed tool rest 30 or the tool units 70 , 80 attached to the tool spindle unit 50 .
In this second machining, similar to the first machining described above, turning or milling is performed on the workpiece W held by the second spindle 21 using the fixed tool unit 70 or the rotating tool unit 80 attached to the tool spindle unit 50.
As in the above-described first machining using the cutting bits 73a and 73b, the second machining uses the cutting bits 73b and 73d of the tool spindle unit 50 to perform turning in sequence. That is, when cutting of the workpiece W using the cutting bit 73b is completed, the tool spindle unit 50 is moved linearly and cutting of the workpiece W using the cutting bit 73d is performed. The order of machining using the cutting bits 73b and 73d may be reversed.

Then, when the second machining is completed, the control unit 300 moves the workpiece W that has undergone the second machining to the workpiece discharge position Po (see Figure 2) via the second spindle moving mechanism 25, and discharges it to the outside in cooperation with a workpiece discharge unit not shown.
This completes the machining process. This machining process is repeated every time a workpiece W is supplied.
In addition, in the first processing or the second processing, the control unit 300 may perform only one of the turning processing and the milling processing, or may perform both the turning processing and the milling processing in a predetermined order.

Next, a description will be given of a tool changing process for changing the type of the tool units 70, 80 attached to the tool spindle unit 50. This tool changing process may be performed during the machining process, or may be performed after the machining process is completed, or before the machining process is started.
In the following, an example in which the tool attached to the tool spindle unit 50 is replaced from the rotating tool unit 80 to the fixed tool unit 70 will be described.

First, as shown in FIG. 1, the control unit 300 rotates the tool support part 61 via the drive unit 62 to move the tool gripping part 61a of the tool support part 61, to which the tool units 70, 80 are not attached, to the tool changing position Pc.
Next, the control unit 300 rotates the rotating tool unit 80 attached to the tool spindle unit 50 in the B-axis direction via the tool turning mechanism 45, and faces the tip side of the tool spindle unit 50 toward the tool magazine 60. Then, the control unit 300 moves the rotating tool unit 80 attached to the tool spindle unit 50 to the radially outer side of the tool support unit 61 with respect to the tool changing position Pc, that is, to the lower side in this example, via the tool spindle moving mechanism 42. Then, the control unit 300 moves the rotating tool unit 80 attached to the tool spindle unit 50 to the radially inner side of the tool support unit 61 with respect to the tool changing position Pc, that is, to the upper side in this example, via the tool spindle moving mechanism 42, and grips the rotating tool unit 80 with the tool gripping portion 61a of the tool support unit 61. Then, after releasing the state in which the tool spindle unit 50 clamps the rotating tool unit 80, the control unit 300 moves the tool spindle unit 50 away from the tool support unit 61 in the Z-axis direction via the tool spindle moving mechanism 42. As a result, the rotating tool unit 80 moves away from the tool spindle unit 50 and is accommodated in the tool gripping portion 61 a of the tool support portion 61 .

Next, the control unit 300 rotates the tool support portion 61 via the drive portion 62 to move the fixed tool unit 70 supported by the tool support portion 61 to the tool changing position Pc.
Then, the control unit 300 moves the tool spindle unit 50, via the tool spindle moving mechanism 42, closer to the fixed tool unit 70 supported by the tool magazine 60 in the Z-axis direction, and attaches the fixed tool unit 70 to the tool spindle unit 50. At this time, the tool spindle unit 50 clamps the fixed tool unit 70.
Then, the control unit 300 moves the tool spindle unit 50 radially outward from the tool support part 61, downward in this example, via the tool spindle moving mechanism 42 to remove the fixed tool unit 70 from the tool support part 61. Then, the tool spindle unit 50 is retracted to the tooling zone side. Finally, as shown in Fig. 4, the tool spindle unit 50 is rotated in the B-axis direction so that the central axis I of the fixed tool unit 70 is aligned along the X-axis direction. This completes the tool replacement process.

(effect)
According to the embodiment described above, the following effects are achieved.
(1) The tool holder 71 attached to the tool spindle unit 50 includes tool holding portions 75a, 75b that hold a plurality of cutting bits 73a to 73d that cut the workpiece W. Cutting edges 73a1 to 73d1 of the plurality of cutting bits 73a to 73d held by the tool holding portions 75a, 75b are positioned apart from one another in a first direction N1, which is an example of an axial direction along the central axis I of the tool holder 71, and in a second direction N2 and a third direction N3, which are examples of intersecting directions intersecting the first direction N1, and are positioned opposite the workpiece W held by the first spindle 11 or the second spindle 21, which is an example of a spindle.
According to this configuration, when changing the cutting bit used for machining the workpiece W among the multiple cutting bits 73a to 73d held by the tool holding portions 75a, 75b, it is only necessary to move the tool spindle unit 50 linearly relative to the workpiece W. This makes it possible to change the cutting bit used for machining without the need to index the tool spindle unit 50. This makes it possible to save the indexing time. In addition, since one tool holder 71 holds multiple cutting bits 73a to 73d, it is possible to reduce the number of times the tool unit attached to the tool spindle unit 50 needs to be replaced. This makes it possible to shorten the cycle time, which is the time required to machine one workpiece W.
In addition, since the multiple cutting bits 73a to 73d can be consolidated into one tool holder 71, compared to a configuration in which one tool holder holds one cutting bit, it is easier to create space in the tool gripping portion 61a of the tool magazine 60. Therefore, the number of tool units 70, 80 housed in the tool magazine 60 can be increased.
Furthermore, the indexing mechanism and locking mechanism of the tool spindle unit 50 are not required, and a simple configuration can be realized.

(2) Cutting edges 73a1, 73b1 of the cutting bit 73a, which is an example of a first cutting bit, and the cutting bit 73b, which is an example of a second cutting bit, held by the tool holding portions 75a, 75b are positioned apart in the third direction N3. The cutting bit 73a cuts the workpiece W held by the first spindle 11. The cutting bit 73b cuts the workpiece W held by the second spindle 21.
According to this configuration, one tool holder 71 attached to the tool spindle unit 50 can machine both the workpiece W held by the first spindle 11 and the workpiece W held by the second spindle 21 through the cutting bits 73a, 73b it holds. As a result, after the cutting bit 73a held in the tool holder 71 machines the workpiece W held by the first spindle 11, the cutting bit 73b held in the tool holder 71 can immediately machine the workpiece W held by the second spindle 21 without replacing the tool holder 71. This makes it possible to shorten the cycle time.

(3) The tool holder 71 includes a tool holding portion 75a, which is an example of a first tool holding portion, and holds a cutting bit 73a, which is an example of a third cutting bit, and a tool holding portion 75b, which is an example of a second tool holding portion, and holds a cutting bit 73c, which is an example of a fourth cutting bit. The tool holding portion 75a includes a first side surface 75a1 that faces the workpiece W cut by the cutting bit 73a in the facing direction (second direction N2). The second tool holding portion 75b includes a second side surface 75b1 that faces the workpiece W cut by the cutting bit 73c in the second direction N2. The first side surface 75a1 and the second side surface 75b1 are arranged in the first direction N1 and are formed at different heights in the second direction N2.
According to this configuration, a step is formed between the first side surface 75a1 and the second side surface 75b1, so that a space is formed below the cutting edge 73a1. This space makes it easy to discharge chips of the workpiece W generated during cutting to the outside.

(4) The machine tool 1 includes a tool holder 71, a tool spindle unit 50 to which the tool holder 71 is attached, a first spindle 11 or a second spindle 21 that holds a workpiece W, and a tool spindle moving mechanism 42 that moves the tool spindle unit 50 so that cutting edges 73a1 to 73d1 of the cutting bits 73a to 73d cut into the outer peripheral surface of the workpiece W.
According to this configuration, in the machine tool 1, it is possible to change the cutting bit to be used without the need to index the tool spindle unit 50.

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 holder 71 has two tool holding parts 75a and 75b that hold two sets of cutting bits, 73a and 73b and 73c and 73d, at different heights, but the number of tool holding parts is not limited to two, and may have three or more tool holding parts that hold three or more sets of cutting bits at different heights. For example, as shown in FIG. 10, the tool holder 71 may have three tool holding parts 75a, 75b, and 75j. The tool holding part 75j is formed in a T-shape similar to the tool holding parts 75a and 75b, is lower in height than the tool holding part 75b, and holds two cutting bits 73e. In this way, by increasing the number of tool holding parts, the number of mounting cutting bits can be increased within the range allowed by the movement stroke of the second spindle 21 and the tool spindle unit 50, etc., and the space allowance of the tool magazine 60.
Further, in the above embodiment, each tool holding portion 75a, 75b is configured to be able to hold two cutting bits, but it may be configured to be able to hold one or three or more cutting bits.

In the above embodiment, the cutting edges 73c1 and 73d1 of the cutting tools 73c and 73d are located at the same height, but this is not limited thereto and they may be located at different heights. Also, the cutting edges 73a1 and 73b1 may be located at different heights.
For example, by changing the height of the cutting bits 73b and 73d relative to the cutting bits 73a and 73c so that the workpiece W and the cutting bits 73a and 73c do not interfere with each other when machining the workpiece W, the cutting bits 73b and 73d can be used to machine the workpiece W held by the first spindle 11. Similarly, the cutting bits 73a and 73c can be used to machine the workpiece W held by the second spindle 21.
Furthermore, the tool holder 75a may hold the cutting bits 73a and 73b at positions shifted in the first direction N1. Similarly, the tool holder 75b may hold the cutting bits 73c and 73d at positions shifted in the first direction N1.
In addition, in the above embodiment, the cutting bits 73a to 73d were held in the tool holder 71 so as to be parallel to each other, but as long as the cutting edges 73a1 to 73d1 are positioned opposite the workpiece W held by the first spindle 11 or the second spindle 21, they do not have to be parallel to each other, and any of the cutting bits 73a to 73d may be held at an angle to the second direction N2.

In the above embodiment, the tool holder 71 holds the cutting bits 73a to 73d in a position along the second direction N2, but the tool holder 71 may hold the cutting bits 73a to 73d in a position along a direction other than the second direction N2. For example, as shown in Figures 11(a), (b), and (c), the tool holder 71A may hold the cutting bits 73a to 73d in a position along the first direction N1. In detail, the tool holder 71A according to this modification includes tool holding parts 95a, 95b and a holding end 95c arranged in the second direction N2, instead of the tool holding parts 75a, 75b and the holding end 75c arranged in the first direction N1 in the above embodiment.
As shown in FIG. 11C, the tool holding portions 95a and 95b each have a T-shape when viewed from the first direction N1. The tool holding portion 95a holds the cutting bits 73a and 73b on both sides in the third direction N3. The tool holding portion 95b holds the cutting bits 73c and 73d on both sides in the third direction N3. The holding end portion 95c is positioned so as to sandwich the cutting bits 73c and 73d between the tool holding portion 95b and the holding end portion 95c. The second end surface 95b1, which is the lower end surface of the tool holding portion 95b, is formed higher toward the cutting edges 73a1 to 73d1 than the first end surface 95a1, which is the lower end surface of the tool holding portion 95a. The lower end surface of the holding end portion 95c is formed higher toward the cutting edges 73c1 and 73d1 than the second end surface 95b1. The tool holder 71A according to this modification, while holding the cutting bits 73a to 73d, can move in the first direction N1 toward the workpiece W while being attached to the tool spindle unit 50 (see FIG. 1), thereby allowing any of the cutting edges 73a1 to 73d1 to cut into the workpiece W. This modification can also provide the same effects as the above embodiment.

In the above embodiment, a step is formed between the first side surface 75a1 and the second side surface 75b1, but the step may be omitted. In this case, the tool holding portions 75a, 75b and the holding end portion 75c may be formed at the same height.

In the above embodiment, the workpiece W is formed of a bar material, but is not limited to this and may be of other shapes such as a disk shape.
In the above embodiment, the fixed tool unit 70 may be used to machine the workpiece W in a state in which at least one of the cutting bits 73a to 73d held by the tool holder 71 is omitted. For example, by omitting the cutting bits so that a plurality of cutting bits are not lined up in the third direction N3, the above-mentioned limitation on the machining width of the workpiece W in the Z-axis direction can be eliminated.

In the above embodiment, the tool spindle unit 50 directly exchanges the tool units 70, 80 with the tool magazine 60, but this is not limited thereto. An ATC (Automatic Tool Changer) may also exchange the tool units 70, 80 between the tool spindle unit 50 and the tool magazine 60.

1...machine tool, 10...first spindle unit, 11...first spindle, 12...first spindle stock, 13...support member, 20...second spindle unit, 21...second spindle, 22...second spindle stock, 25...second spindle movement mechanism, 25X, 42X...X movement mechanism, 25Y, 42Y...Y movement mechanism, 25Z, 42Z...Z movement mechanism, 30...fixed tool rest, 31, 62...drive unit, 35...tool, 42...tool spindle transfer mechanism moving mechanism, 45... tool turning mechanism, 50... tool spindle unit, 51... body, 51b... coupling portion, 51d... fitting recess, 52... spindle, 52a... convex portion, 52b... recess, 54... clamp mechanism, 54a... draw bar, 54b... ball, 60... tool magazine, 61... tool support portion, 61a... tool gripping portion, 70... fixed tool unit, 71, 71A... tool holder, 7 2, 82...tapered portion, 73a to 73e...cutting tool, 73a1 to 73d1...cutting edge, 74...rotation restriction portion, 74a...disk portion, 74b...fitting protrusion, 74c...groove portion, 75a, 75b, 75j, 95a, 95b...tool holding portion, 95a1...first end face, 95b1...second end face, 75a1...first side face, 75b1...second side face, 75c, 95c...holding end portion, 75d to 75g...accommodation recess part, 75h, 75i...screw hole, 75k...screw passage hole, 76, 86...clamp part, 76a, 86a...spherical part, 78...set screw, 79...retained groove part, 80...rotary tool unit, 81...tip, 300...control part, C...rotary axis, I...center axis, N1...first direction, N2...second direction, N3...third direction, S...bed, W...work, Pc...tool exchange position, Po...work ejection position

Claims (3)

A tool holder to be attached to a tool spindle unit,
a first tool holding portion that holds a first cutting bit with a cutting edge facing a workpiece held by a spindle in a facing direction to cut the workpiece, and that has a first side surface that is positioned facing a workpiece to be cut by the first cutting bit in the facing direction ;
a second tool holding portion that holds a second cutting bit with a cutting edge facing the facing direction to cut the workpiece held by the spindle, and that has a second side surface that faces the facing direction to the workpiece to be cut by the second cutting bit ,
cutting edges of the first cutting bit and the second cutting bit are spaced apart in an axial direction along a central axis of the tool holder and are spaced apart in a direction perpendicular to the axial direction and parallel to the facing direction;
The first side surface and the second side surface are aligned in the axial direction and are formed at different heights in the opposing direction.
Tool holder. the first tool holding portion holds a third cutting bit such that a cutting edge of the third cutting bit is positioned away from a cutting edge of the first cutting bit in a direction perpendicular to the axial direction and the facing direction;
the second tool holding portion holds a fourth cutting bit such that a cutting edge of the fourth cutting bit is positioned away from a cutting edge of the second cutting bit in a direction perpendicular to the axial direction and the facing direction;
The first cutting bit and the second cutting bit cut a workpiece held by a first spindle which is the spindle,
The third cutting bit and the fourth cutting bit cut a workpiece held by a second spindle which is a spindle different from the first spindle.
The tool holder of claim 1. A tool holder according to claim 1 or 2 ;
the tool spindle unit to which the tool holder is attached; and
The main shaft;
and a tool spindle moving mechanism that moves the tool spindle unit so that a cutting edge of a cutting bit used for processing cuts into a workpiece held by the spindle.
Machine tools.