Tool rest and machine tool

Abstract

To provide a machine tool, which can prevent a tool from being rattled due to backlash, without complicating a structure thereof, when mounting a tool, which does not rotate, on a tool rest that can rotate a tool thorough a wheel row having backlash and then stopping the tool for use.SOLUTION: The machine tool is provided with: a spindle 33 that attachably and detachably holds a cutting tool 85 in an axis C3-direction; a gear wheel row 33 that transmits rotation to the held cutting tool 85; a draw bar 34 that moves the cutting tool 85 in the axis C3-direction; and a piston 36 provided to be movable in the axis C3-direction between a rearmost position and a frontmost position. Couplings (uneven shapes 36c and 34c) that integrally rotate while contacting each other are formed on the piston 36 and the draw bar 34. The piston 36 is stopped at an intermediate position between the rearmost position and the frontmost position.SELECTED DRAWING: Figure 4A

Description

Technical Field

[0001] The present invention relates to a tool table and a machine tool equipped with this tool table.

Background Art

[0002] There is known a tool table that rotatably holds a rotary tool that detachable holds a workpiece to be machined by rotation, and performs machining of a predetermined workpiece with the rotary tool by rotationally driving the tool holder on which the rotary tool is mounted, and a machine tool equipped with this tool table.

[0003] This machine tool is provided on the tool table with a drawbar that is integrally rotatable and axially movable in the rotational direction with respect to the tool holder as a means for attaching and detaching the rotary tool, and is provided with a piston as an operation driving means for driving the drawbar to advance and retreat. By pressing and moving the drawbar with the piston, the rotary tool can be removed from the tool holder, and the tool can be exchanged (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In this machine tool, it may be necessary to restrict the rotation of the tool holder and fix the rotational direction position of the tool in the tool mounting portion. For example, instead of the rotary tool, a fixed tool such as a tool bit is mounted on the tool holder, and the outer shape or counterboring of the rotating workpiece is performed with the fixed tool without rotating the fixed tool. In this case, it is conceivable to hold the rotary tool while maintaining the phase. However, there is a problem that it is not easy to fix the position of the tool in the rotational direction of the tool mounting portion.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to provide a tool stand that can prevent displacement of a tool held by a tool holding portion in the rotational direction with a simple structure, and a machine tool including the tool stand.

Means for Solving the Problems

[0007] A first aspect of the present invention is a tool stand that detachably holds a tool for machining a workpiece, a tool holding portion that is rotatable about the axis of the tool, and, with respect to the tool holding portion, is integral in the rotational direction about the axis and is provided so as to be able to advance and retreat in the axial direction of the tool. The tool stand includes a detaching and attaching operation means for the tool, and an operation driving means for performing the advancing and retreating drive of the detaching and attaching operation means. By rotationally driving the tool holding portion on which the tool is mounted, the workpiece is machined by the tool, and by pressing the detaching and attaching operation means by the operation driving means and moving it in the axial direction, the tool can be removed from the tool holding portion. In the tool stand, a position is provided in the movement range of the operation driving means where the operation driving means abuts against the detaching and attaching operation means and restricts the rotation of the detaching and attaching operation means.

[0008] A second aspect of the present invention is a machine tool including a spindle for gripping a workpiece, a tool stand according to the present invention, and a control unit for controlling each operation of the spindle and the tool stand. The control unit stops the operation driving means at a position away from the detaching and attaching operation means, a position where the detaching and attaching operation means enables the tool to be detached and attached, and a position where the operation driving means abuts against the detaching and attaching operation means and restricts the rotation of the detaching and attaching operation means.

Effects of the Invention

[0009] In the tool rest and the machine tool equipped with the tool rest according to the present invention, by setting the position of the operation drive means to contact the attachment / detachment operation means so as to position the attachment / detachment operation means at a position where the holding of the tool is maintained, it is possible to easily restrict the rotation of the tool mounting portion and fix the tool mounting portion without complicating the structure. Therefore, for example, when the tool is stopped to machine the workpiece, it is possible to prevent the positional deviation of the tool in the rotation direction and prevent a decrease in machining accuracy, etc. In addition, it is possible to maintain and hold the phase in the rotation direction of the tool that rotates and machines as needed.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4A

Figure 4B

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8

Figure 9A

Figure 9B

Embodiments for Carrying Out the Invention

[0011] The automatic lathe 100 shown in Fig. 1 is an embodiment of a machine tool according to the present invention. The automatic lathe 100 includes, inside a cover, as shown in Fig. 2, a main shaft 10, a comb-tooth blade tool rest 20, and a tool spindle 30 which is an example of a tool rest according to the present invention.

[0012] Based on the operation of the operation panel 90, in the automatic lathe 100, a control unit 80 housed inside the cover below the operation panel 90 controls the operations of the main shaft 10, the comb-tooth blade tool rest 20, and the tool spindle 30.

[0013] The main shaft 10 is supported so as to be movable in the z-axis direction parallel to the axis and is rotationally driven around the axis C1.

[0014] A guide bush 55 is provided on a guide bush support base 51 arranged in front of the main shaft 10, and the tip side of the workpiece held by the main shaft 10 protrudes into the machining chamber 50 from the guide bush 55.

[0015] The comb-tooth blade tool rest 20 and the tool spindle 30 are arranged inside the machining chamber 50. The comb-tooth blade tool rest 20 supports a plurality of tools 21, 22, …, 25.

[0016] By moving the comb-tooth blade tool rest 20 along the y-axis orthogonal to the z-axis, the automatic lathe 100 selects one of the tools 21, …, 25 used for machining. By moving the comb-tooth blade tool rest 20 along the x-axis orthogonal to the z-axis and the y-axis respectively, the selected tools 21, …, 25 machine the workpiece.

[0017] As shown in FIG. 3A, a rotary tool 86 and a cutting tool 85 integrally mounted on a holder are mounted on a tool spindle 30. The rotary tool 86 is detachably inserted into a tool drive shaft rotatably supported by the main body of the tool spindle 30. The cutting tool 85 is detachably mounted on a spindle 33 rotatably supported about an axis C3 below the tool drive shaft.

[0018] By moving the tool spindle 30 along the x-axis, the cutting tool 85 or the rotary tool 86 can be selected as the tool used for machining the workpiece. By moving the tool spindle 30 along the y-axis, the workpiece can be machined by the selected cutting tool 85 or rotary tool 86.

[0019] The tool spindle 30 is rotatable about an axis C2 parallel to the x-axis, and the cutting tool 85 or the rotary tool 86 can be tilted with respect to the y-axis to machine the workpiece.

[0020] The movement of the tool spindle 30 along the x-axis, the movement along the y-axis, the rotation about the axis C2, and the rotation of the cutting tool 85 and the rotary tool 86 about the axis C3 are controlled by a control unit 80.

[0021] As shown in FIGS. 3A, 4A, and 5A, a rotational driving force is input to a gear 32a through a bevel gear 32a1 that meshes with a drive gear (not shown) inserted into the upper end opening 31 of the tool spindle 30, and the gear 32b is rotationally driven through a spur gear 32a2. The gear 32b meshes with a gear 32c provided integrally with the tool drive shaft, and the gear 32c meshes with a gear 32e through a gear (not shown), and the rotational driving of the gear 32b is sequentially transmitted from the gear 32c to the gear 32e.

[0022] The tool drive shaft is rotated by the rotational driving force transmitted to the gear 32c, and the rotary tool 86 is rotationally driven. The gear 32e is integrally mounted on a spindle 33 (an example of a tool holding portion).

[0023] The spindle 33 is a tool holder that detachably holds the cutting tool 85 along the axis C3 direction and rotatably holds the cutting tool 85 around the axis C3. The cutting tool 85 is configured such that the tool body 85a is integrally gripped by a collet chuck to the holder 85b. A pull stud 85d is integrally provided on the holder 85b, and the pull stud 85d protrudes to the opposite side of the tool body 85a.

[0024] The holder 85b is formed in a conical shape. The spindle 33 forms a tapered hole on the inside. When the holder 85b is inserted into the hole of the spindle 33, the inclined surface 85c of the holder 85b comes into contact with and adheres closely to the inner peripheral surface 33a of the hole, and the cutting tool 85 is mounted on the spindle 33.

[0025] The hole of the spindle 33 is formed with a concave groove 33b having an inner diameter larger than the minimum inner diameter portion of the taper over the entire circumference at the back of the inner peripheral surface 33a with the taper formed. The hole of the spindle 33 has a ball pressing portion 33c formed as an inner peripheral surface having an inner diameter smaller than the inner diameter of the concave groove 33b on the further back side than this concave groove 33b.

[0026] The drawbar 34 (an example of the detaching and attaching operation means) is disposed inside the spindle 33 so as to be movable (retractable and extendable) along the axis C3. The front end of the drawbar 34 is provided with a plurality of balls 34a that engage with the pull stud 85d provided on the holder 85b from the outside. A coil spring 35 is provided outside the drawbar 34.

[0027] The coil spring 35 is provided between a stopper integrally provided at the rear end of the drawbar 34 and a stepped portion formed in the hole of the spindle 33. The drawbar 34 is biased rearward by the coil spring 35. The drawbar 34 is restricted from moving rearward by more than a certain length by hitting against a stopper 33d formed on the spindle 33.

[0028] When the drawbar 34 resists the biasing force of the coil spring 35 and the ball 34a is in a position facing the concave groove 33b of the spindle 33 as shown in FIG. 3A, the ball 34a escapes from the inner side of the front end of the drawbar 34 to the radially outer concave groove 33b, allowing the attachment and detachment of the pull stud 85d inside the inner side of the front end of the drawbar 34.

[0029] When the holder 85b is inserted into the hole of the spindle 33 and the cutting tool 85 is attached to the spindle 33 with the ball 34a escaping from the inner side of the front end of the drawbar 34 to the radially outer concave groove 33b, the pull stud 85d is inserted inside the inner side of the front end of the drawbar 34.

[0030] When the cutting tool 85 is attached to the spindle 33 and the drawbar 34 is moved rearward by the biasing of the coil spring 35, the ball 34a of the drawbar 34 moves from the position facing the concave groove 33b to the position facing the ball pressing portion 33c. The ball 34a pressed radially inward from the ball pressing portion 33c protrudes partially inside the inner side of the front end of the drawbar 34, engages with the pull stud 85d, the holder 85b of the cutting tool 85 is integrally held by the spindle 33, and the cutting tool 85 can rotate integrally with the spindle 33.

[0031] As shown in FIG. 6, the drawbar 34 and the spindle 33 are engaged with each other by the spline 34s of the drawbar 34 and the spline 34s on the inner peripheral surface of the spindle 33, and the drawbar 34 is movable along the axis C3 with respect to the spindle 33 while rotation about the axis C3 is restricted.

[0032] A cylinder 38 is formed on the outer peripheral side behind the spindle 33 on the main body of the tool spindle 30. A piston 36 (an example of operating drive means) is provided in the cylinder 38 so as to be able to advance and retreat along the axis C3. The piston 36 has a rod portion 36b protruding rearward, which passes through a through hole formed in the seal receiving member 37 of the main body of the tool spindle 30 and advances (moves forward) and retreats (moves backward) along the axis C3. The piston 36 drives the drawbar 34 to advance and retreat.

[0033] As shown in FIG. 7, the rod portion 36b has an outer peripheral surface 36s formed in a hexagonal cross-sectional contour shape, and the through-hole of the seal receiving member 37 is formed as a hexagonal hole having an inner peripheral surface 37s with a hexagonal cross-sectional contour shape corresponding to the hexagonal cross-sectional contour shape of the rod portion 36b. The rod portion 36b is movable along the axis C3 with respect to the seal receiving member 37 and is restricted from rotating around the axis C3. The movement of the piston 36 is performed with rotation around the axis C3 restricted.

[0034] By supplying an operating fluid such as air under the control of the control unit 80 to the section on the left side of the piston 36 in the cylinder 38 in the drawing, the piston 36 can be advanced, and by supplying an operating fluid such as air under the control of the control unit 80 to the section on the right side of the piston 36 in the cylinder 38 in the drawing, the piston 36 can be retracted.

[0035] The piston 36 is movable within a range between the most retracted rearmost position shown in FIGS. 5A and 5B and the most advanced foremost position shown in FIGS. 3A and 3B under the control of the control unit 80 described above. Further, the piston 36 is controlled by the control unit 80 to stop at a predetermined intermediate position (position) shown in FIGS. 4A and 4B within the movement range between the rearmost position and the foremost position.

[0036] With the piston 36 disposed at the rearmost position, the front surface 36a is separated rearward from the rear end surface 34b of the drawbar 34. At the rearmost position of the piston 36, the cutting tool 85 is held by the drawbar 34 on the spindle 33, and the spindle 33 can rotate or stop the cutting tool 85.

[0037] As shown in FIG. 8, on the front surface 36a of the piston 36 facing the rear end surface 34b of the drawbar 34, a concave portion and a convex portion each extend radially about the axis C3, and these concave and convex portions are alternately repeated at equal intervals along the circumferential direction around the axis C3 to form an uneven shape 36c. As shown in FIGS. 9A and 9B, an uneven shape 34c corresponding to the uneven shape 36c is formed on the rear end surface 34b of the drawbar 34 facing the front surface 36a of the piston 36.

[0038] The uneven shape 36c of the piston 36 and the uneven shape 34c of the drawbar 34 can engage with each other.

[0039] When the piston 36 moves forward from the rearmost position shown in FIGS. 5A and 5B to the intermediate position shown in FIGS. 4A and 4B, the front surface 36a of the piston 36 and the rear end surface 34b of the drawbar 34 come into contact, and the uneven shape 36c and the uneven shape 34c shown in FIG. 9B are in a combined state.

[0040] By engaging the uneven shape 36c and the uneven shape 34c of the drawbar 34 with each other, the piston 36 and the drawbar 34 become integral around the axis C3. At the intermediate position, the piston 36 does not press the drawbar 34 to move it in the direction of the axis C3, and the drawbar 34 stops without moving forward or backward with respect to the spindle 33. The spindle 33 maintains the holding of the cutting tool 85, and the rotational position of the cutting tool 85 is maintained.

[0041] Note that at the intermediate position, the piston 36 may press and move the drawbar 34 within the range where the spindle 33 maintains the holding of the cutting tool 85.

[0042] The control unit 80 controls the piston 36 to move forward and stop at the foremost position, presses the drawbar 34 by the piston 36, and moves the drawbar 34 to a position where the attachment and detachment of the pull stud 85d are allowed, thereby attaching and detaching the holder 85b to and from the spindle 33 and detaching and attaching the cutting tool 85.

[0043] Further, when the automatic lathe 100 processes a workpiece rotating around the axis C1 with the cutting tool 85 stopped without rotating, the control unit 80 stops a drive source such as a motor that rotationally drives the gear train 32, or prevents rotation from being transmitted to a drive gear (not shown) connected to the gear train 32.

[0044] Even when the transmission of the driving force to the drive gear is stopped so as to stop the rotational drive of the spindle 33, the positional deviation in the rotational direction that may occur due to backlash or the like between the connected gears 32a, 32b, 32c, 32e is prevented by moving the piston 36 to the intermediate position, and the cutting tool 85 is fixed with the positional deviation in the rotational direction being prevented.

[0045] For example, as the tool body 85a of the cutting tool 85, a fixed tool such as a tool bit that processes a workpiece without rotating is attached. When processing a workpiece rotating around the axis C1, the cutting edge of the tool body 85a is prevented from deviating from a preset position due to friction with the rotating workpiece or from generating so-called chatter vibration due to fluctuations in friction, and it is possible to prevent a decrease in machining accuracy in operations such as boring the workpiece and machining the outer shape of the outer peripheral surface of the workpiece.

[0046] As described in detail above, the automatic lathe 100 of the present embodiment has a simple structure in which the front surface 36a of the piston 36 and the rear end surface 34b of the tool carrier 34 are brought into contact when a fixed tool is attached to the tool spindle 30 as the tool body 85a and the spindle 33 is stopped for use. Also, by a simple control in which the control unit 80 stops the piston 36 at a predetermined position (intermediate position) set within the range between the rearmost position and the foremost position, it is possible to prevent positional deviation in the rotational direction of the tool body 85a and prevent the cutting edge of the tool body 85a from moving.

[0047] On the front surface 36a of the piston 36 and the rear end surface 34b of the drawbar 34, uneven shapes 36c and 34c serving as couplings are formed, and by engaging the uneven shapes 36c and 34c, the front surface 36a of the piston 36 and the rear end surface 34b of the drawbar 34 can be brought into contact with each other.

[0048] Instead of forming the uneven shapes 36c and 34c on the front surface 36a of the piston 36 and the rear end surface 34b of the drawbar 34 respectively, the front surface 36a of the piston 36 and the rear end surface 34b of the drawbar 34 can be formed in a state with a high coefficient of friction or provided with members having a high coefficient of friction, and the front surface 36a of the piston 36 and the rear end surface 34b of the drawbar 34 can be brought into contact with each other in a high-friction state.

Explanation of Signs

[0049] 33 Spindle (an example of a tool holding part) 34 Drawbar (an example of a detaching and attaching operation means) 36 Piston (an example of an operation driving means) 30 Tool spindle (an example of a tool table) 100 Automatic lathe (an example of a machine tool)

Claims

1. A tool holding part that rotatably holds a tool for machining a workpiece around the axis of the tool in a detachable manner, A tool attaching / detaching operation means that is integrally provided in the rotational direction around the axis with respect to the tool holding part and is movable forward and backward in the axial direction of the tool, An operation driving means for driving the forward and backward movement of the attaching / detaching operation means, and comprising, By rotationally driving the tool holding part on which the tool is mounted, the workpiece is machined by the tool, and by pressing the attaching / detaching operation means by the operation driving means and moving it in the axial direction, in a tool rest capable of removing the tool from the tool holding part, A tool rest provided with a position in the movement range of the operation driving means where the operation driving means abuts against the attaching / detaching operation means and restricts the rotation of the attaching / detaching operation means.

2. The tool rest according to claim 1, wherein concavo-convex shapes that mesh with each other in a state where the operation driving means and the attaching / detaching operation means are in contact with each other are formed on the surfaces where the operation driving means and the attaching / detaching operation means abut against each other.

3. The tool rest according to claim 2, wherein the concavo-convex shape is such that the concave part and the convex part each extend radially around the axes of the operation driving means and the attaching / detaching operation means, and the concave part and the convex part are alternately repeated at equal intervals along the circumferential direction around the axis.

4. The tool rest according to claim 1, wherein the cross-sectional contour shape of the outer peripheral surface of the rod part of the operation driving means and the cross-sectional contour shape of the inner peripheral surface of the seal receiving member through which the rod part passes are formed in a shape that allows the operation driving means to move along the axial direction and prevents the operation driving means from rotating around the axis.

5. A spindle for gripping a workpiece, The tool rest according to any one of claims 1 to 4, And a control unit for controlling each operation of the spindle and the tool rest. The control unit stops the operation driving means at a position away from the attachment / detachment operation means, a position where the attachment / detachment operation means can attach / detach the tool, and a position where the operation driving means abuts against the attachment / detachment operation means to restrict the rotation of the attachment / detachment operation means, a machine tool.

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