JP2009166196A - Rotation indexing unit for machine tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently drive a rotation indexing unit by decreasing a power loss accompanied by a sliding resistance, by further decreasing a size of a rotary joint included in the rotation indexing unit, and decreasing an area of a sliding face in the rotary joint. <P>SOLUTION: The rotation indexing unit (1) for a machining tool includes: a rotation shaft (6) rotatably provided in a frame (2), for supporting a rotary driven object (10); and rotary joints (15, 32) for supplying machining fluid to the rotary driven object (10), wherein a plurality of cables (27, 43) pulled out from the rotary driven object (10) are arranged in a state of inserting through the frame (2) in an axial direction of the rotation shaft (6). In this rotation indexing unit (1), at least one of the cables (27) is arranged outside of an outer peripheral surface of a hollow cylindrical part (17) of a member positioned radially outside of a distributor (16) and a shaft (21) constituting a sliding part of the rotary joint (15). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a rotary indexing device for a machine tool including a rotary joint that supplies electric power and fluid pressure to a rotationally driven object that rotates.

Patent Document 1 discloses a spindle head having a fork-shaped drive unit (A-axis drive unit) for supporting and rotating a spindle unit that rotates a spindle on which a tool is mounted in a machine tool such as a so-called machining center. is doing. In the spindle head, the A-axis drive unit is supported by a sleeve (36), and is rotationally driven around the C-axis by a motor rotor (70) of a DD motor attached to the sleeve (36). Both the A-axis drive unit and the part that rotationally drives the A-axis drive unit around the C-axis (C-axis drive unit) function as a rotary indexing device that indexes the rotation angle and stops at a predetermined position. . The A-axis drive unit includes a DD motor as a drive source, and although not shown, the spindle unit also includes a drive motor (spindle motor).

On the other hand, Patent Document 2 relates to an index table (rotary table device) as a rotary indexing device, and discloses that the rotary table device includes a rotary joint.

In the rotary indexing devices represented by these, as in the device described in Patent Document 1, the rotationally driven object that is rotationally driven often has an electrical drive unit. In this case, it is necessary to wire a power supply cable for supplying power to the drive unit.

This cable is wired in the state of the axis of the rotation shaft that supports the rotation drive object in the frame of the rotation indexing device in order to avoid the cable being swung around the rotation drive object. Is done. In general, it is common practice to wire the cable near the axis of the rotating shaft in order to suppress twisting of the cable in the frame. That is, in the rotary indexing device, a through hole is generally formed at the center of the rotating shaft, and the cable as described above is wired in the through hole.

When the rotary indexing device includes a rotary joint as described in Patent Document 2, for example, when the rotary joint is constituted by a cylindrical distributor and a shaft fitted to the distributor, the distributor A configuration is generally adopted in which a through hole is formed at the center of the cable and the cable is wired in the through hole.

However, in such a configuration, when the cable is thick and / or the number of the cables is large, there arises a problem that the sliding resistance of the rotary joint increases. Specifically, with the rotation of the rotary shaft of the rotary indexing device, the distributor and the shaft rotate relative to each other while their fitting surfaces slide. Further, since a seal member is interposed between the two, the sliding resistance is larger than that in the case of simply sliding. The sliding resistance between the two is proportional to the area of the sliding surface, and the area is proportional to the diameter of the sliding portion surface. Therefore, the sliding resistance increases as the diameter of the sliding surface increases. When the cables to be wired as described above are thick and / or the number of cables is large, the through holes for wiring the cables have to be large in diameter. As a result, the area of the sliding surface between the distributor and the shaft increases accordingly, and as a result, the sliding resistance associated with the relative rotation of both increases. If the sliding resistance between the distributor and the shaft in the rotary joint is large, the power loss increases accordingly.
US Patent 5,584,621 Specification JP 2002-36047 A

Accordingly, an object of the present invention is to reduce the power loss associated with the sliding resistance by making the rotary joint included in the rotary indexing device smaller in diameter and reducing the area of the sliding surface in the rotary joint. Thus, the rotational indexing device can be driven efficiently.

Under the above-mentioned problems, the invention according to claim 1 supports the rotationally driven object (10) via a rotating body (3) provided rotatably at the end of the frame (2). A rotary joint (15, 32) provided concentrically with the rotary shaft (6) and the rotary shaft (6) with respect to the axis of the rotary shaft (6) for processing the rotary drive object (10) And a plurality of cables (27, 43) drawn from the rotationally driven object (10) are inserted in the axial direction of the rotary shaft (6). In the rotary indexing device (1) for machine tools wired in the state where it is wired, the rotary joints (15, 32) are provided so as not to rotate relative to the frame (2) (16, 33). ) And before It comprises shafts (21, 38) fitted so as to be rotatable relative to the distributors (16, 33). One of the distributors (16, 33) and the shafts (21, 38) is the rotating body (3 ) Has a shaft portion (22, 34) arranged with its axis aligned with the center of rotation, and the other has a hollow cylindrical portion (17, 39) fitted to the shaft portion (22, 34). At least one of the cables (27, 43) is connected to the distributor (16, 33) of the rotary joint (15, 32) and the hollow cylindrical portion (17, 39) on the other side of the shaft (21, 38). ) Is wired outside the outer peripheral surface.

In Claim 2 dependent on Claim 1, the shaft (22, 34) of one of the distributor (33) and the shaft (21) is formed solid, and the cables (27, 43) are: All of them are wired outside the outer peripheral surface of the hollow cylindrical portion (17, 39).

According to the first aspect of the present invention, the rotary shaft (6) which is rotatably provided in the frame (2) and supports the rotationally driven object (10) via the rotary body (3) provided at the end. A rotary joint (15, 32) for supplying a working fluid to the rotational drive object (10), and a plurality of cables (27, 43) drawn from the rotational drive object (10) In the rotary indexing device (1) for machine tools wired in a state of being inserted through the frame (2) in the axial direction of the rotary shaft (6), a sliding portion of the rotary joint (15, 32) is configured. Among the distributors (16, 33) and the shafts (21, 38), a small number of the cables (27, 43) are arranged outside the outer peripheral surface of the hollow cylindrical portion (17, 39) of the member located on the radially outer side. Also from wire the one can be a number of conventional rotary joint internal cables are wired in less or eliminated. As a result, the rotary joint can be made smaller in diameter, the area of the sliding surface between the rotary joint distributor and the shaft can be reduced, and the power loss associated with the sliding resistance generated on the sliding surface can be reduced to reduce the rotational split. The dispensing device can be driven efficiently.

Moreover, even when a through hole is formed in the shaft core portion of the rotary joint and the cable is wired, the diameter of the through hole is smaller than when all of the plurality of cables are wired in the through hole. can do. As a result, the area of the sliding surface between the distributor and the shaft can be reduced, the sliding resistance can be reduced, and the power loss can be reduced.

According to the second aspect of the invention, in the first aspect of the invention, of the distributors (16, 33) and the shafts (21, 38) of the rotary joints (15, 32), the shafts of members located radially inward Since the parts (22, 34) are solid, and the cables (27, 43) are all wired outside the outer peripheral surface of the hollow cylindrical part (17, 39), the shaft of the rotary joint The diameter of the shaft portion (22, 34) of the rotary joint (15, 32) can be significantly reduced as compared with the case where the cable is routed by forming a through hole in the core portion. Can be further increased.

The rotary indexing device that is the subject of the present invention includes, in addition to the rotary indexing table of the embodiment described below, for example, a part that drives the spindle unit to rotate around the A axis in the spindle head of a 5-axis machine (A (Axis drive unit) and a portion (C axis drive unit) that rotationally drives the A axis drive unit around an axis line (C axis) parallel to the Z axis of the machine tool. That is, the rotational indexing device is a concept that widely includes devices that rotationally drive a rotational drive target that supports a workpiece, a tool, and the like and bring (rotate) the rotational drive target to a predetermined rotational position (angular position). Hereinafter, an example in which the present invention is applied to a rotary indexing table will be described.

FIG. 1 shows a rotary indexing table 1 as an example of a rotary indexing apparatus to which the present invention is applied. In general, the rotary indexing table 1 is a device in which a rotating shaft 6 that supports a circular table 3 as a rotating body is rotatably attached to a frame 2 serving as a base, and includes a rotating table device, an index table, and a rotary table. It is also called.

The rotation index table 1 will be described in more detail. The circular table 3 is fixed to one end of a rotary shaft 6 that is rotatably provided in the frame 2, and is supported rotatably with respect to the frame 2 by a bearing 8 fixed to the frame 2. The rotary shaft 6 includes a rotary sleeve 7 that constitutes an outer shell of the rotary shaft 6, a bearing retainer 9 that is fixed to the rotary sleeve 7 with screws and sandwiches the inner ring of the bearing 8 together with the rotary sleeve 7, and a shaft 21 of a rotary joint 15 described later. It consists of and. The circular table 3 is fixed to the bearing retainer 9 with screws, whereby the circular table 3 rotates integrally with the rotary shaft 6. In this example, the rotary table 3 as a rotating body is formed separately from the rotating shaft 6, but the rotating body may be a portion formed integrally with the rotating shaft 6.

The circular table 3 is formed with a through hole 4 used for wiring or the like, and a part of the inner peripheral surface of the through hole 4 (a rotary joint 15 side described later) projects inward in the radial direction. Part 5 is formed. The stepped portion 5 also protrudes toward the rotary joint 15 in the axial direction of the rotating shaft 6 and is fitted into the bearing retainer 9 by a so-called inlay type. Further, the circular table 3 is fitted into the inner peripheral surface of a clamp sleeve 48 whose outer peripheral surface is fixed to the frame 2. The clamp sleeve 48 has a diameter contracted by hydraulic pressure, and clamps the rotary table 3 in a non-rotatable manner.

On the other hand, on the circular table 3, for example, a jig device (device for holding a workpiece) is mounted as the rotational drive target 10. In addition to the jig device, various objects can be conceived as the rotationally driven object 10 depending on the mode of use of the rotary indexing table 1. For example, another rotary indexing table may be mounted on the circular table 3 of the rotary indexing table 1, and in this case, another rotary indexing table on the circular table 3 becomes the rotation drive target 10. .

The rotary indexing table 1 also has a DD motor 11 (direct (direct drive type) drive motor) that directly drives the rotary shaft 6 without using a drive transmission mechanism such as a gear as a drive means for the rotary shaft 6. Built-in. The DD motor 11 includes a motor rotor 12 and a motor stator 13. The motor rotor 12 is fixed to the rotating sleeve 7 of the rotating shaft 6, and the motor stator 13 is unrotatable to the stator sleeve 14 fixed to the frame 2. It is inserted. In this example, a DD motor is adopted as the driving means for the rotating shaft 6. However, instead of the DD motor, for example, a worm gear that drives a worm wheel fixed to the rotating shaft 6 by a worm connected to the driving motor. A mechanism may be adopted.

Next, the rotary joint 15 built in the rotary indexing table 1 will be described. In general, the rotary joint 15 is for supplying a working fluid from the main body side of the rotary indexing table 1 to the rotating target 10 to be rotated, and is fixed to the non-rotating member, that is, the frame 2. And a shaft 21 that rotates together with the rotary member, that is, the rotary table 3 and the rotary shaft 6. The machining fluid here is, for example, a working fluid for a clamping device that clamps a workpiece when the rotationally driven object 10 is the jig device described above. Further, when the rotary indexing device is the above-described spindle head, cooling coolant liquid or water supplied to the spindle unit, air for removing chips generated during processing, and the like can be used.

The rotary joint 15 will be described in detail. The rotary joint 15 is provided concentrically with respect to the axis of the rotary shaft 6, is provided so as not to rotate relative to the frame 2, and receives a processing fluid supplied from the outside of the apparatus. 16 and a shaft 21 which is fitted so as to be relatively rotatable with respect to the distributor 16 and receives supply of a processing fluid from the distributor 16. In general, there are two possible radial positional relationships between the distributor and the shaft: passing the shaft inside the distributor and fitting the shaft outside the distributor, but here the shaft is placed inside the distributor. The case where the shaft is fitted to the outside of the distributor in Example 2 (FIG. 3) described later will be described.

The distributor 16 has a hollow cylindrical portion 17 fitted to a shaft portion 22 (described later) of the shaft 21 and a flange portion 18 fixed to the frame 2 and formed integrally with the hollow cylindrical portion 17. . Inside the hollow cylindrical portion 17 and the flange portion 18, a plurality of fluid flow paths 19 that are supplied with processing fluid from the outside of the rotary indexing table 1 are formed at different positions in the circumferential direction. The passage 19 communicates with a plurality of annular grooves 20 formed on the inner peripheral surface of the hollow cylindrical portion 17.

On the other hand, the shaft 21 is disposed with its axis aligned with the rotation center of the circular table 3, and a shaft portion 22 that fits into the hollow cylindrical portion 17 of the distributor 16, and a flange that is fixed to the circular table 3 and the bearing retainer 9. Part 23. A plurality of annular grooves 24 are formed on the outer peripheral surface of the shaft portion 22 at positions corresponding to the annular grooves 20 of the hollow cylindrical portion 17 of the distributor 16. The plurality of annular grooves 24 are respectively formed on the shaft portion 22 and the flange portion. A plurality of fluid flow paths 25 are formed in the inside of the pipe 23 while being displaced in the circumferential direction. As described above, the shaft 21 is fixed to the rotary sleeve 7 that is a part of the rotary table 3 and the rotary shaft 6 by the flange portion 23, and rotates integrally with the rotary table 3 and the rotary sleeve 7. Therefore, the shaft 21 corresponds to a part of the rotary shaft 15 as well as a part of the rotary shaft 6.

Even when the rotary shaft 6, that is, the shaft 21 is rotated, the state where the fluid flow path 19 on the distributor 16 side and the fluid flow path 25 on the shaft 21 side are connected is maintained by the rotary joint 15 configured as described above. The processing fluid supplied from the outside of the apparatus is supplied to the rotationally driven object 10 through the fluid channel 19, the fluid channel 25, and the fluid channel 26 formed inside the circular table 3.

On the other hand, a plurality of power supply cables 27 that supply power to the rotational drive target 10 are drawn out from the rotational drive target 10. As a specific example of the cable 27, when the rotational drive target 10 has an electrical drive unit, for example, when another rotary indexing table is mounted on the circular table 3 of the rotary indexing table 1 described above. Is a power supply cable (power cable) for supplying power to a drive motor or the like of another rotary indexing table. In addition, the signal line etc. which were connected to the sensors (rotation detector etc.) with which the rotation drive object 10 was equipped are also contained.

The cable 27 drawn from the rotational drive object 10 passes through the through hole 4 from the circular table 3 side and is drawn into the rotary indexing table 1, and is formed in each member inside the rotary indexing table 1. 28, 29, 30 are routed, inserted in the axial direction of the rotary shaft 6, penetrated through the rotary indexing table 1, and provided on the end surface of the anti-circular table 3 side in the axial direction of the flange portion 18 of the distributor 16. It is held by the cable guide 31 and is further wired toward a power circuit (not shown) on the machine tool side. The cable 27 is twisted in the frame 2 as the rotational drive object 10, the rotary table 3, and the rotary shaft 6 are rotated. However, when the workpiece is processed, the rotary table 3 is rotated once or more in the same direction. Since the cable 27 is rarely rotated, twisting of the cable 27 is not particularly problematic if the cable 27 is wired with a certain margin in the frame 2.

The notches 28, 29, and 30 are formed in the step portion 5 of the circular table 3, the flange portion 23 of the shaft 21, and the flange portion 18 of the distributor 16, respectively. These notches 28, 29, and 30 are formed in a sector shape over a predetermined range in the circumferential direction of the above-described member (a range that allows the movement of the cable 27 accompanying the rotation of the circular table 3) (FIG. 2). ).

In this way, the notches 28, 29, and 30 for passing the cable 27 are formed in the step portion 5 of the circular table 3, the flange portion 23 of the shaft 21, and the flange portion 18 of the distributor 16, so that the rotary joint 15 (the flange portion 18) is formed. It is possible to pass the cable 27 outside the flange portion 23).

In FIG. 2, all twelve cables 27 are wired outside the main body of the rotary joint 15, that is, outside the outer peripheral surface of the hollow cylindrical portion 17 of the distributor 16 in this example. Thereby, the diameter of a rotary joint can be made small compared with the case where a through-hole is formed in the axial part of a rotary joint and a cable is wired. As a result, the area of the sliding surface between the distributor and the shaft can be reduced, the sliding resistance can be reduced, and the power loss can be reduced.

In this example, in order to maximize the effects of the present invention, the shaft portion 22 of the shaft 21 is formed in a solid rod shape so that the diameter of the rotary joint is as small as possible, and the cable is passed through the rotary joint body. However, all of the plurality of cables are wired outside the rotary joint body, but a through hole is formed in the shaft portion 22 of the shaft 21, and one or several of the plurality of cables are Even in the case of wiring in the through hole, the diameter of the through hole can be made smaller than in the case where all of the plurality of cables are wired in the through hole. As a result, the area of the sliding surface between the distributor and the shaft can be reduced, the sliding resistance can be reduced, and the power loss can be reduced.

FIG. 3 shows an example in which the radial positional relationship between the distributor of the rotary joint and the shaft is opposite to that in the first embodiment. That is, in this example, the rotary joint 32 has a configuration in which the shaft 38 is fitted to the outside of the distributor 33.

The rotary joint 32 is provided concentrically with respect to the axis of the rotary shaft 6, is provided so as not to rotate relative to the frame 2, and receives a supply of machining fluid from the outside of the apparatus, and is relative to the distributor 33. The shaft 38 is rotatably fitted and receives a processing fluid from the distributor 33.

The distributor 33 includes a shaft portion 34 that is fitted into a hollow cylindrical portion 39 (described later) of the shaft 38, and a flange that is integrally formed with the shaft portion 34 and that is not rotatable relative to the frame 2 by a rotation stopper 44. Part 35. Inside the shaft portion 34 and the flange portion 35, a plurality of fluid flow paths 36 that receive supply of a machining fluid from the outside of the indexing circular table 1 are formed at different positions in the circumferential direction. The path 36 communicates with a plurality of annular grooves 37 formed on the outer peripheral surface of the shaft portion 34.

On the other hand, the shaft 38 is arranged with its axis aligned with the rotation center of the circular table 3, and is formed integrally with the hollow cylindrical portion 39 and the hollow cylindrical portion 39 that fits with the shaft portion 34 of the distributor 33. And a flange portion 40 fixed to the table 3 and the bearing retainer 9. A plurality of annular grooves 41 are formed on the inner peripheral surface of the hollow cylindrical portion 39 at positions corresponding to the annular grooves 37 of the shaft portion 34 of the distributor 33. A plurality of fluid flow paths 42 are formed in the flange portion 40 at different positions in the circumferential direction.

Similarly to the first embodiment, a plurality of power supply cables 43 that supply power to the rotational drive target 10 are drawn out from the rotational drive target 10. The cable 43 passes through the through hole 4 from the circular table 3 side and is drawn into the rotary indexing table 1, and passes through the notches 45 and 46 formed in the step portion 5 of the table 3 and the flange portion 40 of the shaft 38. An anti-circular table on the inner peripheral surface of the rotary sleeve 7 (fixed to the circular table 3) that is wired so as to pass through, is inserted in the axial direction of the rotary shaft 6 and penetrates the rotary index table 1 and surrounds the rotary joint 32. It is held by a cable guide 47 formed by projecting inward in the radial direction at the side end, and further wired toward a power supply circuit (not shown) of the machine tool. The rotary sleeve 7 in which the cable guide 47 is formed rotates integrally with the rotary shaft 6 (shaft 38) and the rotary table 3, and the cable 43 held by the cable guide 47 on the rotary sleeve 7 is also in the frame 2. The cable 43 is not twisted in the frame 2 because it rotates together. Therefore, in this example, it is not necessary to consider the movement of the cable 43 in forming the notches 45 and 46 (there is enough space to pass the cable 43).

FIG. 4 is a schematic view of a spindle head to which the present invention can be applied. The spindle head refers to a device that is used in a machine tool such as a 5-axis machine and supports a spindle unit that rotationally drives a spindle on which a tool is mounted to drive the spindle. When the spindle head shown here is mounted on a 5-axis machine, the entire spindle head moves in the XYZ direction of the machine tool, and the spindle unit supported by the spindle head has an axis parallel to the XY plane ( Rotate around the A axis) and around the axis parallel to the Z axis (C axis). The A-axis drive unit and the spindle unit that are rotationally driven by the C-axis drive unit incorporate a drive motor, a fluid pressure clamp, and the like. The C-axis drive unit and the A-axis drive unit supply power to the drive motor and the like. A cable to be supplied is inserted, and a rotary joint for supplying a working fluid is incorporated.

Now, paying attention to the A-axis drive unit, the rotator referred to in the present invention is a joint part provided on a support shaft (rotary shaft) that supports the spindle unit and to which the spindle unit is attached. Is a unit. If attention is paid to the C-axis drive unit, the rotating body referred to in the present invention is a joint part to which the A-axis drive unit is attached, and the rotation drive target is the A-axis drive unit.

Thus, the present invention is not limited to the rotary indexing tables of the first and second embodiments, but can be applied to a spindle head for driving the spindle unit shown in FIG. The spindle head is not limited to the fork type shown in FIG. 4 (supporting the spindle unit on both sides), but cantilevered as shown in JP-A-3-178709. Also good.

The present invention can be widely applied to an apparatus including a rotary joint that rotationally drives a rotating object and supplies fluid and electric power to the rotating object that is rotating.

It is sectional drawing of the rotation index table 1. FIG. It is a top view of the rotation index table 1. FIG. It is sectional drawing of the rotation index table 1. FIG. It is a schematic diagram of the spindle head of a 5-axis processing machine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotary indexing table as a rotary indexing device for machine tools 2 Frame 3 Circular table 4 as a rotating body 4 Through hole 5 Step part 6 Rotating shaft 7 Rotating sleeve 8 Bearing 9 Bearing holder 10 Rotation drive object 11 DD motor 12 Motor rotor 13 Motor stator 14 Stator sleeve 15 Rotary joint 16 Distributor 17 Hollow cylindrical part 18 Flange part 19 Fluid flow path 20 Annular groove 21 Shaft 22 Shaft part 23 Flange part 24 Annular groove 25 Fluid flow path 26 Fluid flow path 27 Cable 28 Notch 29 Notch 30 Notch 31 Cable guide 32 Rotary joint 33 Distributor 34 Shaft 35 Flange 36 Fluid channel 37 Annular groove 38 Shaft 39 Hollow cylindrical part 40 Flange 41 Annular groove 42 Fluid channel 43 Cable 44 Anti-rotation 45 Notch Part 46 notch 47 cable guide 48 clamp sleeve

Claims (2)

A rotating shaft (6) that is rotatably provided in the frame (2) and supports a rotationally driven object (10) via a rotating body (3) provided at an end, and an axis of the rotating shaft (6) A rotary joint (15, 32) provided concentrically with the rotating shaft (6), and a rotary joint (15, 32) for supplying a working fluid to the rotationally driven object (10). Indexing for machine tools, in which a plurality of cables (27, 43) drawn from the rotational drive object (10) are wired in the axial direction of the rotating shaft (6) In device (1):
The rotary joints (15, 32) include a distributor (16, 33) provided so as not to rotate relative to the frame (2) and a shaft fitted so as to be rotatable relative to the distributor (16, 33). 21 and 38), one of the distributor (16, 33) and the shaft (21, 38) is arranged with the shaft portion (22, 34), and the other has a hollow cylindrical portion (17, 39) fitted to the shaft portion (22, 34),
At least one of the cables (27, 43) is connected to the distributor (16, 33) of the rotary joint (15, 32) and the hollow cylindrical portion (17, 39) on the other side of the shaft (21, 38). A rotary indexing device (1) for a machine tool, characterized in that it is wired outside the outer peripheral surface. One of the shaft portions (22, 34) of the distributor (16, 33) and the shaft (21, 38) is solid, and the cables (27, 43) are all formed in the hollow cylindrical portion. The rotary indexing device (1) for machine tools according to claim 1, characterized in that wiring is provided outside the outer peripheral surface of (17, 39).

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