NC rotary table device

Abstract

This NC circular table that has a reduced dimension in the machine width direction comprises: a spindle which is rotatably supported by a front-side bearing and a rear-side bearing and which has a rotary table fixed to the front-side end thereof; a servomotor which is disposed rearward of the rear-side bearing and which has a rotary shaft positioned parallel to the centerline of the spindle; and a rotation transmission mechanism which is disposed between the rotary shaft of the servomotor and the spindle. The front-side bearing, for example, comprises two single-row tapered roller bearings that are disposed to face each other across a prescribed distance therebetween.

Description

[Technical Field]

[0001] The present invention relates to an NC rotary table device with a reduced width dimension. [Background technology]

[0002] An NC rotary table device is mounted on an NC machine tool and rotates or phases a workpiece held by a chuck or the like. Patent Document 1 listed below discloses a conventional NC rotary table device mounted on a machine tool. A slide block is movably mounted on the table of the machine tool, and the NC rotary table device is mounted on the slide block. A column is erected next to the NC rotary table device, and tools and the like are mounted on it to process the workpiece held by the NC rotary table device.

[0003] An NC rotary table unit is configured so that a rotary table is integrally formed with a spindle whose centerline is the slide direction, and rotation is transmitted to the spindle, to which a worm wheel is fixed, via a worm shaft. This rotating structure is incorporated into the table body, and a servo motor is incorporated in a motor housing box fixed to its side. The servo motor's drive control then imparts rotation to the worm shaft, and the worm wheel controls the rotation of the spindle and rotary table. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-44614 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional NC rotary table devices are Rotating StructureThe spindle is covered by the table body, and a motor housing box containing a built-in servo motor is integrally formed next to it. Therefore, although the axial dimension of the spindle is short, the width perpendicular to the axial direction is large, making it unsuitable for machine tools with limited machine width. In other words, while the width dimension is not an issue with the machine tool of Patent Document 1, it does not meet the requirements of machine tools designed for compactness or machine tools with limited internal space. Furthermore, in conventional NC rotary table devices, the servo motor is located close to the rotary table, making it susceptible to the effects of coolant forcefully sprayed inside the machine tool and chips generated during workpiece machining.

[0006] Therefore, in order to solve the above problem, an object of the present invention is to provide an NC rotary table device having a reduced dimension in the width direction of the machine body. [Means for solving the problem]

[0007] The NC rotary table device according to one aspect of the present invention comprises a spindle rotatably supported by a front bearing and a rear bearing and having a rotary table fixed to its front end, a servo motor whose rotation axis is parallel to the center line of the spindle and is disposed behind the rear bearing, and a servo motor incorporating the spindle. Roughly rectangular parallelepiped a main body block; and a rotation transmission mechanism disposed in the main body block and provided between the rotation shaft of the servo motor and the spindle; The servo motor is disposed parallel to a rotary joint provided at the rear end of the spindle within a width dimension of the main body block in a direction perpendicular to the center line of the spindle. . [Effects of the Invention]

[0008] According to the above configuration, the spindle to which the rotary table is fixed and the rotation axis of the servo motor are arranged parallel to each other, and the servo motor is positioned behind the spindle, resulting in an NC rotary table with a reduced width dimension. [Brief explanation of the drawings]

[0009] [Figure 1]FIG. 1 is a perspective view showing the internal structure of a machining center equipped with an NC rotary table device. [Figure 2] FIG. 1 is a plan view showing an embodiment of an NC rotary table device. [Figure 3] 3 is a cross-sectional view of the NC rotary table device shown in FIG. 2 taken along the line AA. [Figure 4] FIG. 4 is a cross-sectional view of the NC rotary table device shown in FIG. 3 taken along the arrow BB. [Figure 5] FIG. 4 is a cross-sectional view of the NC rotary table device shown in FIG. 3 taken along the arrow CC. [Figure 6] FIG. 4 is a cross-sectional view corresponding to FIG. 3, showing an NC rotary table device according to a second embodiment that can be used as a spindle device. [Figure 7] FIG. 1 is a front view showing a processing machine line made up of a plurality of modularized working machines. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of an NC rotary table device according to the present invention will be described below with reference to the drawings. Fig. 1 is a perspective view showing the internal structure of a machining center equipped with an NC rotary table device. The machining center 1 is entirely covered by a machine body cover (not shown), and inside is a machining chamber 4, shown by a dashed line, where workpiece machining takes place. The machining center 1 is mounted on a movable bed 11 and is structured so as to be movable in the front-rear direction on a base 2.

[0011] The machining center 1 is one of the work machines 85 that make up the processing machine line 80 shown in Figure 7. In the processing machine line 80, a plurality of work machines 85, such as the machining center 1, machine tools such as lathes, and inspection devices, are lined up close together in the width direction. In particular, the work machines 85 that make up the processing machine line 80 are modularized and configured compactly with a fixed width dimension. In the case of the processing machine line 80, two of each work machine 85 are mounted on one base 2 (see Figure 1).

[0012] The machining center 1 is configured so that a spindle head 12 for holding tools is provided at the front, and is equipped with a spindle chuck 13 to which a tool such as a drill can be attached or detached, and the attached tool is rotated by a spindle motor 14. The spindle head 12 is mounted on a processing drive device 3 so that it can move in three axes for processing, part replacement, etc. The processing drive device 3 is equipped with an X-axis slide 16 that moves in the width direction of the machine body relative to a Y-axis slide 15 that moves in the front-to-rear direction of the machine body, and a Z-axis slide 17 that moves in the up-and-down direction of the machine body relative to the X-axis slide 16. The movement of each slide is configured so that the rotational output of a servo motor is converted into linear motion by a ball screw mechanism.

[0013] Below the spindle head 12, which is moved by the machining drive device 3, there are provided an NC rotary table device 18 equipped with a chuck device 75 for gripping a workpiece, and a tool magazine 19 located above it. The tool magazine 19 stores a plurality of tools between the NC rotary table device 18 and the spindle head 12, and an automatic tool changer is installed inside the door that opens and closes. The machining center 1 is equipped with a control device 5 at the rear of the machine body for controlling the drive of the spindle head 12, NC rotary table device 18, machining drive device 3, tool magazine 19, etc.

[0014] The machining center 1 of the processing machine line 80 is configured such that the Y-axis slide 15, X-axis slide 16, and Z-axis slide 17 of the processing drive device 3 are arranged in the longitudinal direction of the machine body to minimize the width, and an NC rotary table unit 18 and a tool magazine 19 are stacked underneath. Each device is configured to minimize the width. FIG. 2 is a plan view showing the NC rotary table unit 18. FIG. 3 is a cross-sectional view of the NC rotary table unit 18 shown in FIG. 2, taken along the line AA. FIG. 4 is a cross-sectional view of the NC rotary table unit 18 shown in FIG. 3, taken along the line BB. FIG. 5 is a cross-sectional view of the NC rotary table unit 18 shown in FIG. 3, taken along the line CC.

[0015] The NC rotary table device 18 is a so-called B-axis table that is placed horizontally with its center of rotation horizontal, and is incorporated into a main body block 21. A cylindrical support member 22 is fixed inside the main body block 21, and a spindle 23, which is a hollow rotary shaft, is rotatably incorporated within it via bearings. The spindle 23 protrudes forward from the main body block 21, and an annular rotary table 25 is fixed to it. The spindle 23 is longer in the axial direction than conventional examples, and extends from the machining chamber 4 to the rear of the machine body (in the Y-axis direction shown in Figure 1).

[0016] On the other hand, the NC rotary table device 18 has a reduced width D shown in Fig. 2. For example, the modularized work machine 85 shown in Fig. 7 has a machine body width of 450 mm excluding the hobbing machine 85n, and the NC rotary table device 18 incorporated in the machining center 1 has a width D of 420 mm. Therefore, the servo motor 31 of the NC rotary table device 18 is disposed rearward of the machine body relative to the position of the spindle 23, and is connected via a rotation transmission mechanism.

[0017] The spindle 23 is rotatably supported by a front bearing 27 and a rear bearing 28. In particular, the front bearing 27 is configured with increased rigidity to support the load during workpiece machining. A jig 70, such as a chuck device 75 shown in FIG. 1, is detachably attached to the rotary table 25 of the NC rotary table unit 18 at the position indicated by the dashed line. A workpiece is held by the jig 70, which is fixed so as to protrude forward of the NC rotary table unit 18, and machining is performed by applying a tool to the workpiece in a direction perpendicular to the rotation axis. Therefore, a load is applied to the spindle 23 of the NC rotary table unit 18 during machining from a direction perpendicular to the rotation axis, with the workpiece in an overhanging state.

[0018] In the conventional NC rotary table devices mentioned above, the axial dimension of the spindle is short and the bearing rigidity is low, which causes a problem of reduced machining accuracy due to the effect of the load generated during machining. In contrast, the NC rotary table device 18 has a long axial dimension spindle 23 supported by a front bearing 27 and a rear bearing 28. Furthermore, the front bearing 27 uses two single-row tapered roller bearings that are spaced a predetermined distance apart and face each other, thereby increasing rigidity. The rear bearing 28 is a double-row cylindrical roller bearing and is located near the rotation transmission mechanism that transmits rotation from the servo motor 31.

[0019] The NC rotary table device 18 of the machining center 1 not only has limited space in the width direction of the machine body, but also has the movable bed 11 located directly below and the tool magazine 19 located above. Therefore, the servo motor 31 is located behind the spindle 23 and is arranged so as to fit within the width dimension of the main body block 21. The servo motor 31 is arranged so that its rotation axis 310 is parallel to the center line O of the spindle 23, and between them are provided a first transmission shaft 33 and a second transmission shaft 34 that are orthogonal to each other as shown in Figure 5, which form a rotation transmission mechanism that transmits rotation at a reduced speed.

[0020] The servo motor 31 has a first transmission shaft 33 coaxially connected to a rotary shaft 310 by a shaft coupling 35. The first transmission shaft 33, which is rotatably supported by a holder portion 36 via a bearing, has a small bevel gear 37 fixed to the opposite end of the shaft coupling 35, and is in mesh with a large bevel gear 38 fixed to one end of a second transmission shaft 34 that is perpendicular to the spindle 23. An orthogonal reducer is configured between the second transmission shaft 34, which is rotatably supported by the bearing, and the spindle 23. The orthogonal reducer is a Roller Drive (registered trademark), and a roller gear cam 41, shown without the screw, is formed on the second transmission shaft 34 on the input side, and a turret 42, with a plurality of roller followers provided on the outer periphery, is formed on the spindle 23 on the output side.

[0021] When a workpiece is machined in the machining center 1, the NC rotary table device 18 holds the workpiece in a jig 70 fixed to the rotary table 25, and the phase of the workpiece is aligned by drive control of the servo motor 31. The rotation of the servo motor 31 rotates the first transmission shaft 33, which is then transmitted at a reduced speed to the orthogonal second transmission shaft 34 via the small bevel gear 37 and large bevel gear 38. The rotation of the second transmission shaft 34 is further transmitted at a reduced speed to the turret 42 via the roller gear cam 41, causing the spindle 23 to rotate.

[0022] In the NC rotary table device 18 of this embodiment, the spindle 23 to which the rotary table 25 is fixed and the rotation axis of the servo motor 31 are arranged parallel to each other, and the servo motor 31 is located behind the spindle 23, thereby reducing the width dimension. The NC rotary table device 18 has a front bearing 27 that receives a large load during workpiece machining, and the front bearing 27 is configured with two single-row tapered roller bearings spaced a predetermined distance apart to increase rigidity, thereby achieving stable machining and improving machining accuracy. Furthermore, because the servo motor 31 is located far from the rotary table 25, the NC rotary table device 18 is less susceptible to the effects of the coolant used during workpiece machining and chips generated during machining.

[0023] Incidentally, the work machines 85 that make up the processing machine line 80 include lathes and other machine tools in addition to the machining center 1. A chuck device is also attached to the spindle of the lathe. However, some lathe spindle devices are configured to open and close the chuck using the output of a hydraulic cylinder. Therefore, in the following second embodiment, an improved version of the NC rotary table device 18 of the first embodiment will be described, which can be used as the spindle device of a lathe.

[0024] First, the NC rotary table device 18 is provided with a rotary joint 45 behind the spindle 23. The rotary joint 45 has a hollow rotating shaft 46 coaxially fixed to the end of the spindle 23 via a spacer 47, and the rotating shaft 46 is inserted into a non-rotating joint block 48 via a bearing. The rotating shaft 46 has multiple annular grooves, each of which has a continuous flow path that runs axially through the spindle. The joint block 48 is also formed with multiple ports that correspond to the annular grooves of the rotating shaft 46, allowing for the supply and discharge of hydraulic oil.

[0025] The NC rotary table device 18 is capable of operating a jig fixed to the rotary table 25 using hydraulic oil via this rotary joint 45. In contrast, the spindle device of a lathe is configured to use a hydraulic cylinder to open and close the chuck. Figure 6 is a cross-sectional view corresponding to Figure 3, showing an NC rotary table device of a second embodiment that can be used as such a spindle device. The same components as those of the NC rotary table device 18 of the first embodiment are designated by the same reference numerals, and detailed explanations will be omitted.

[0026] In the NC rotary table device 50 of the second embodiment, a spindle 23 is rotatably mounted in a main body block 21 via two front bearings 27, which are single-row tapered roller bearings, and a rotary table 25 is fixed to its front end. A servo motor 31 parallel to the spindle 23 is connected to a first transmission shaft 33 and a second transmission shaft 34 that are perpendicular to each other via bevel gears 37 and 38, and the second transmission shaft 34 and the spindle 23 are connected by a RollerDrive® system in which a roller gear cam 41 meshes with a turret 42. The rotary joint 45 of the NC rotary table device 18 has been replaced with a cylinder-equipped rotary joint 52 equipped with a hydraulic cylinder 51.

[0027] In the cylinder-equipped rotary joint 52, a rotating cylinder 53 is fixed coaxially to the end of the spindle 23, and the rotating cylinder 53 is inserted into a non-rotating joint block 54 via a bearing. A piston 55 is built into the rotating cylinder 53, and a piston rod 56 protrudes in the axial direction. The rotating cylinder 53 also has multiple annular grooves, and each annular groove has a continuous flow path that runs axially through the spindle 23.

[0028] Meanwhile, joint block 54 has a plurality of ports formed therein, which are connected to the annular groove of rotary cylinder 53 and to the front and rear pressurizing chambers that pressurize piston 55. An inductor 58 is fixed to piston rod 56 that protrudes rearward from piston 55. Piston 55 and piston rod 56 are hollow, and a pipe-shaped draw bar 61 is fixed to piston rod 56 and inserted into hollow spindle 23. An air pipe 62 connected to inductor 58 is inserted into draw bar 61.

[0029] In the NC rotary table device 50, when a workpiece is gripped via a chuck 77 fixed to the rotary table 25, hydraulic oil is supplied and discharged via the cylinder-equipped rotary joint 52, and the displacement of the piston 55 operates a draw bar 61 that passes through the spindle 23, opening and closing the chuck jaws. Once the workpiece is gripped by the chuck 77, seating of the workpiece is detected by air supplied through the inductor 58. Then, the rotation is transmitted to the spindle 23 by the drive control of the servo motor 31, and cutting or other processing is performed on the workpiece by the rotation of the chuck 77.

[0030] The NC rotary table device 50 of this embodiment has a reduced width dimension, similar to the first embodiment, and can therefore be used as a spindle device for a modularized lathe that constitutes the same machining machine line 80. The NC rotary table device 50 has the same main configuration as the first embodiment, and the front bearing 27 is composed of two single-row tapered roller bearings, providing sufficient rigidity to improve machining accuracy. Furthermore, the servo motor 31 of the NC rotary table device 50 is located far from the rotary table 25, making it less susceptible to the effects of the coolant used during workpiece machining and chips generated during machining.

[0031] Although one embodiment of the present invention has been described, the present invention is not limited to this embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above embodiment, a modularized machining center 1 or lathe with a reduced width has been used as an example, but the NC rotary table of the present invention is also effective for machines with narrow installation spaces in the machine. In addition to the width dimension, it is also effective to use the NC rotary table in order to ensure rigidity against loads during workpiece machining and to protect the servo motor from coolant, etc. Also, for example, a worm gear may be used in the rotation transmission structure that transmits rotation from the second transmission shaft 34 to the spindle 23. [Explanation of symbols]

[0032] 1...Machining center 3...Processing drive device 18...NC rotary table device 21...Main block 23...Spindle 25...Rotary table 27...Front bearing 28...Rear bearing 31...Servo motor 33...First transmission shaft 34...Second transmission shaft 37...Small bevel gear 38...Large bevel gear 41...Roller gear cam 42...Turret 45...Rotary joint 52...Rotary joint with cylinder 80...Processing machine line

Claims

1. a spindle rotatably supported by a front bearing and a rear bearing, the spindle having a rotary table fixed to its front end; a servo motor whose rotation axis is parallel to the center line of the spindle and is disposed rearward of the rear bearing; a substantially rectangular parallelepiped main body block incorporating the spindle; a rotation transmission mechanism disposed in the main body block and provided between the rotation shaft of the servo motor and the spindle; and The servo motor is arranged in parallel with a rotary joint provided at the rear end of the spindle within a width dimension of the main body block in a direction perpendicular to the center line of the spindle.

2. 2. The NC rotary table apparatus according to claim 1, wherein the front bearing comprises two single-row tapered roller bearings arranged facing each other at a predetermined distance.

3. 3. The NC rotary table apparatus according to claim 1, wherein the rotation transmission mechanism comprises: a first transmission shaft connected to the servo motor; a second transmission shaft perpendicular to the spindle; a bevel gear that transmits rotation between the first transmission shaft and the second transmission shaft; and an orthogonal reducer consisting of a roller gear cam formed on the second transmission shaft and a turret formed on the spindle.

4. 4. The NC rotary table device according to claim 1, wherein the spindle is a hollow shaft, and the rotary joint provided at the rear end of the spindle is replaceable with a rotary joint with a cylinder that has a built-in hydraulic cylinder that operates a drawbar that passes through the hollow shaft.

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