Machine tool provided with clamping jig for rotationally-symmetrical body

Abstract

Provided is a machine tool which performs a cutting work on a workpiece, in which holes are provided at three or more points in a circumferential direction of a jig in the vicinity of a point at which the jig comes into contact with the workpiece when the workpiece is placed on the jig, and the workpiece is moved toward a rotation center of the jig by blowing air from an air supply unit toward the workpiece through the holes.

Claims

1. A machine tool, comprising: a jig configured to fix a workpiece to perform a cutting work on the workpiece; an arm configured to press the workpiece against the jig; a rotating table configured to rotate the workpiece; and an air supply unit configured to supply air, wherein the arm includes holes at three or more points on a circumference in the vicinity of a point at which the arm comes into contact with the workpiece when the workpiece is fixed to the jig, the air supply unit is configured to supply the air through the holes, wherein the arm includes an arm protrusion configured to be inserted into a center hole of the workpiece wherein the arm protrusion projects into only a part of the center hole of the workpiece, the holes are provided in the arm protrusion, the machine tool further comprises a pressure adjusting unit configured to control a pressure of the air which is discharged from each of the holes and is blown toward the workpiece placed on the jig, the holes are disposed at intervals which are not equal to each other, and the pressure adjusting unit is configured to control the pressure of the air from the holes which are closer to each other to be lower than the pressure of the air from the holes which are farther from each other.

2. The machine tool according to claim 1, wherein the arm has a width and a length greater than the width, the length of the arm is oriented in a radial direction of the rotating table, and the arm protrusion extends from an end of the arm downwardly, along a rotational axis of the rotating table, toward the jig.

3. A machine tool, comprising: a jig configured to fix a workpiece to perform a cutting work on the workpiece; an arm configured to press the workpiece against the jig; a rotating table configured to rotate the workpiece; and an air supply unit configured to supply air, wherein the arm includes holes at three or more points on a circumference in the vicinity of a point at which the arm comes into contact with the workpiece when the workpiece is fixed to the jig, the air supply unit is configured to supply the air through the holes, the arm includes an arm center hole portion into which a protrusion of the workpiece is to be inserted, the holes are provided in the arm center hole portion, a pressure adjusting unit configured to control a pressure of the air which is discharged from each of the holes and is blown toward the workpiece placed on the jig, the holes are disposed at intervals which are not equal to each other, and the pressure adjusting unit is configured to control the pressure of the air from the holes which are closer to each other to be lower than the pressure of the air from the holes which are farther from each other.

4. A machine tool, comprising: a jig configured to fix a workpiece to perform a cutting work on the workpiece; an arm configured to press the workpiece against the jig; a rotating table configured to rotate the workpiece; and an air supply unit configured to supply air, wherein the arm includes holes at three or more points on a circumference in the vicinity of a point at which the arm comes into contact with the workpiece when the workpiece is fixed to the jig, the air supply unit is configured to supply the air through the holes, the arm includes an arm center hole portion into which a protrusion of the workpiece is to be inserted, the holes are provided in the arm center hole portion, the arm has a width and a length greater than the width, the length of the arm is oriented in a radial direction of the rotating table, the arm protrusion extends from an end of the arm downwardly, along a rotational axis of the rotating table, toward the jig, and the holes are oriented radially inwardly toward an interior of the arm center hole portion, and are configured to blow the air supplied from the air supply unit radially inwardly toward the protrusion of the workpiece.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above and other objects and features of the invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings in which:

(2) FIG. 1 is a schematic view of a machine tool according to the invention;

(3) FIG. 2 is a view (side sectional view) illustrating the relationship between a workpiece and a jig in a first embodiment of the machine tool according to the invention;

(4) FIG. 3 is a view of the jig of FIG. 2 in a state where the workpiece is removed when viewed from above;

(5) FIG. 4 is a view (side sectional view) illustrating the relationship between a workpiece and a jig in a second embodiment of the machine tool according to the invention;

(6) FIG. 5 is a view of the jig of FIG. 4 in a state where the workpiece is removed when viewed from above;

(7) FIG. 6 is a view (side sectional view) illustrating the relationship between a workpiece and a jig in a third embodiment of the machine tool according to the invention;

(8) FIG. 7 is a view of an arm and a protrusion of FIG. 6 in a state where the jig and the workpiece are removed when viewed from below;

(9) FIG. 8 is a view (side sectional view) illustrating the relationship between a workpiece and a jig in a fourth embodiment of the machine tool according to the invention;

(10) FIG. 9 is a view (side sectional view) illustrating the relationship between a workpiece and a jig in a fifth embodiment of the machine tool according to the invention;

(11) FIG. 10 is a view (side sectional view) illustrating the relationship between a workpiece and a jig in a sixth embodiment of the machine tool according to the invention; and

(12) FIG. 11 is a view (side sectional view) illustrating the relationship between a workpiece and a jig in a seventh embodiment of the machine tool according to the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(13) A machine tool according to the invention includes a rotating table 10 as illustrated in FIG. 1. A jig 12 is provided on the rotating table 10, and a workpiece 14 having the shape of a rotationally-symmetrical body is fixed onto the jig 12. The workpiece 14 is fixed to the jig 12 by being pressed against the jig 12 by an arm 16 provided above the workpiece 14 (as described later, there may be cases where the workpiece 14 is fixed to the jig 12 without the use of the arm 16 depending on circumstances). The workpiece 14 fixed to the jig 12 is rotated by the rotating table 10 and is machined by a tool 18.

(14) First, a first embodiment of the machine tool according to the invention will be described with reference to FIGS. 2 and 3.

(15) Air supply holes 52 (52a, 52b, and 52c) are provided in the upper surface of the jig 12 is provided with in the vicinity of a location where the jig 12 comes into contact with the workpiece 14 when the workpiece 14 is placed on the jig 12. As illustrated in FIG. 3, the air supply holes 52a, 52b, and 52c are provided at three points in the upper surface of the jig 12 at equal distances from the rotation center C and at equal angles (120 degrees therebetween). In addition, the three air supply holes 52a, 52b, and 52c are connected to an air supply unit 100 and are configured such that air supplied from the air supply unit 100 is blown from each of the air supply holes 52a, 52b, and 52c toward the workpiece 14.

(16) It is preferable to align the rotation center of the workpiece with the rotation center C of the jig. However, in an initial stage in which the workpiece 14 is mounted on the jig 12, the rotation center C of the jig 12 and the rotation center of the workpiece 14 are not aligned with each other during the mounting. In this case, in this embodiment, air is blown toward the air supply holes 52a, 52b, and 52c at the three points from the air supply unit 100 at the same degree of pressure.

(17) As an example, in FIG. 2, it is assumed that the workpiece 14 is mounted in a state of being slightly biased toward the left with respect to the rotation center C of the jig 12. In this case, the gap between the workpiece 14 and the jig 12 is narrow on the left side and is wide on the right side. When air is blown from the air supply holes 52 in this state, the pressure in the gap between the jig 12 and the workpiece 14 on the left side with a narrower gap is higher than that on the right side. Therefore, a force to move the workpiece 14 from the left toward the right is exerted. As a result, the workpiece 14 is moved from the left side toward the right side in such a direction in which the rotation center thereof is aligned with the rotation center C of the jig 12. In this manner, the rotation center of the workpiece 14 is centered to be aligned with the rotation center of the jig 12 by blowing air from the air supply holes 52. After the rotation center of the workpiece 14 is aligned with the rotation center of the jig 12, the workpiece 14 is clamped by the jig 12 and may be machined.

(18) In addition, in this embodiment, an example in which the air supply holes 52 are provided at the three points (52a, 52b, and 52c) is used for the description. However, even in a case where the air supply holes 52 are provided at four or more points, the same effect is obtained. In addition, in this embodiment, the air supply holes 52 positioned at the three points are provided with equal intervals therebetween. However, the air supply holes 52 may also be disposed with intervals therebetween which are not equal to each other and the pressure of the air blown from each of the air supply holes 52 is adjusted by a pressure adjusting unit (not illustrated) such that the pressure of the air from the air supply holes 52 which are close to each other is set to be low and the pressure of the air from the air supply holes 52 which are far from each other is set to be high. Accordingly, the rotation center of the workpiece 14 can be centered to be aligned with the rotation center of the jig 12 by blowing the air from the air supply holes 52. The same is applied to the other embodiments as follows.

(19) Next, a second embodiment of the machine tool according to the invention will be described with reference to FIGS. 4 and 5.

(20) In this embodiment, the jig 12 has a protrusion 24 in the vicinity of the rotation center C thereof, and the protrusion 24 is configured to be fitted into the center hole 22 provided in the workpiece 14.

(21) In this embodiment, air supply holes 54 are provided in the upper surface of the protrusion 24 of the jig 12 in the vicinity of a location where the protrusion 24 comes into contact with the workpiece 14 when the workpiece 14 is placed on the jig 12. As illustrated in FIG. 5, the air supply holes 54 are provided at three points (air supply holes 54a, 54b, and 54c), and as illustrated in FIG. 5, the air supply holes 54a, 54b, and 54c are provided at the three points in the upper surface of the jig 12 at equal distances from the rotation center C and at equal angles (120 degrees therebetween). In addition, the three air supply holes 54a, 54b, and 54c are connected to an air supply unit (not illustrated) and are configured such that air supplied from the air supply unit is blown from each of the air supply holes 54a, 54b, and 54c toward the workpiece 14. The supply of the air from the air supply unit toward the air supply holes 54 and a mechanism for moving the workpiece 14 toward the direction of the rotation center C of the jig 12 by supplying the air are the same as those of the first embodiment described above.

(22) Next, a third embodiment of the machine tool according to the invention will be described with reference to FIGS. 6 and 7.

(23) In this embodiment, the arm 16 has a protrusion 26 in the vicinity of a site through which the rotation center C of the jig 12 passes, and the protrusion 26 is configured to be fitted into a center hole 28 provided in the workpiece 14.

(24) In this embodiment, air supply holes 56 are provided in the lower surface of the protrusion 26 of the arm 16 in the vicinity of a location where the protrusion 26 comes into contact with the workpiece 14 when the workpiece 14 is placed on the jig 12. As illustrated in FIG. 7, the air supply holes 56 are provided at three points (air supply holes 56a, 56b, and 56c), and as illustrated in FIG. 7, the air supply holes 56a, 56b, and 56c are provided at the three points in the lower surface of the protrusion 26 of the arm 16 at equal distances from the rotation center C and at equal angles (120 degrees therebetween). In addition, the three air supply holes 56a, 56b, and 56c are connected to an air supply unit (not illustrated) and are configured such that air supplied from the air supply unit is blown from each of the air supply holes 56a, 56b, and 56c toward the workpiece 14. The supply of the air from the air supply unit toward the air supply holes 56 and a mechanism for moving the workpiece 14 toward the direction of the rotation center C of the jig 12 by supplying the air are the same as those of the first embodiment described above.

(25) Next, a fourth embodiment of the machine tool according to the invention will be described with reference to FIG. 8.

(26) In this embodiment, the workpiece 14 is provided with a protrusion 30, and the protrusion 30 of the workpiece 14 is configured to be inserted into a center hole provided in the arm 16.

(27) In this embodiment, air supply holes 58 are provided in the lower surface of the arm 16 in the vicinity of a location where the arm 16 comes into contact with the workpiece 14 when the workpiece 14 is placed on the jig 12. The air supply holes 58 are provided at three points, and the air supply holes 58 are provided at the three points in the lower surface of the arm 16 at equal distances from the site through which the rotation center C passes and at equal angles (120 degrees therebetween). In addition, the air supply holes 58 provided at the three points are connected to an air supply unit (not illustrated) such that air supplied from the air supply unit is blown. In addition, the three air supply holes 58 are connected to an air supply unit (not illustrated) and are configured such that the air supplied from the air supply unit is blown from each of the air supply holes 58 toward the workpiece 14. The supply of the air from the air supply unit toward the air supply holes 58 and a mechanism for moving the workpiece 14 toward the direction of the rotation center C of the jig 12 by supplying the air are the same as those of the first embodiment described above.

(28) Next, a fifth embodiment of the machine tool according to the invention will be described with reference to FIG. 9.

(29) In this embodiment, a drawing bar 34 is mounted on the jig 12 and is configured such that the drawing bar 34 is fitted into a center hole 32 provided in the workpiece 14 and the workpiece 14 is drawn in the jig 12 via the drawing bar 34 fitted into the workpiece 14.

(30) In this embodiment, three points of the outer periphery of the drawing bar 34 are provided with air supply holes 60 at equal intervals therebetween (120 degrees therebetween). The air supply holes 60 are connected to a conduit having the same axis as the center axis of the drawing bar 34 and to an air supply unit (not illustrated) which is connected to the conduit such that the air supplied from the air supply unit is blown from the air supply holes 60 of the drawing bar 34. The supply of the air from the air supply unit toward the air supply holes 60 and a mechanism for moving the workpiece 14 toward the direction of the rotation center C of the jig 12 by supplying the air are the same as those of the first embodiment described above.

(31) Next, a sixth embodiment of the machine tool according to the invention will be described with reference to FIG. 10.

(32) Even in this embodiment, as in the fifth embodiment described above, the drawing bar 34 is mounted on the jig 12, and the drawing bar 34 is fitted into a center hole 36 provided in the workpiece 14. A difference from the fifth embodiment is that the center hole 36 of the workpiece 14 does not penetrate through the workpiece 14 to the top and is provided to reach an intermediate position of the workpiece 14.

(33) In this embodiment, three points of the outer periphery of the drawing bar 34 are provided with air supply holes 62 at equal intervals therebetween (120 degrees therebetween). The air supply holes 62 are connected to a conduit having the same axis as the center axis of the drawing bar 34 and to an air supply unit (not illustrated) which is connected to the conduit such that the air supplied from the air supply unit is blown from the air supply holes 62 of the drawing bar 34. The supply of the air from the air supply unit toward the air supply holes 62 and a mechanism for moving the workpiece 14 toward the direction of the rotation center C of the jig 12 by supplying the air are the same as those of the first embodiment described above.

(34) Next, a seventh embodiment of the machine tool according to the invention will be described with reference to FIG. 11.

(35) In this embodiment, the workpiece 14 is provided with a protrusions 38, and the protrusions 38 is configured to be inserted into a jig center hole 40 provided in the jig 12.

(36) In this embodiment, air supply holes 64 are provided in the jig 12 such that the supply holes 64 may be blocked by the protrusion 38 of the workpiece 14 when the protrusion 38 of the workpiece 14 is inserted into the center hole 40 of the jig 12. Three air supply holes 64 are provided on the circumference in the jig center hole 40 about the rotation center C of the jig 12 with equal intervals therebetween (at an angle of 120 degrees therebetween). The three air supply holes 64 are connected to an air supply unit (not illustrated) and are configured such that air supplied from the air supply unit is blown from each of the air supply holes 64 toward the workpiece 14. The supply of the air from the air supply unit toward the air supply holes 64 and a mechanism for moving the workpiece 14 toward the direction of the rotation center C of the jig 12 by supplying the air are the same as those of the first embodiment described above.

(37) In addition, the invention can be appropriately modified to, in addition to the above-described embodiments, a configuration in which air supply holes are provided in the jig 12 and the peripheral members thereof or in the arm 16 and the peripheral members thereof and air is blown from the air supply holes. The number of air supply holes may be four or more, and a plurality of air supply holes may not necessarily be disposed with equal intervals therebetween.