JPS6128442B2 - - Google Patents

Description

[Detailed Description of the Invention] It has a plurality of spindles, and the workpiece is attached to the spindles via chucks to increase machining efficiency and to aim for high productivity, which is generally popular especially in the industrial field for mass production. By the way. The machine tool of the embodiment to which the present invention is applied is constructed in view of the above situation, and in particular, the chuck attached to the main spindle can be automatically replaced with another chuck, has a conveying function, and is particularly designed for two-axis This machine tool is equipped with an automatic chuck changer and has a main spindle.

Conventionally, production systems for turning for mass production have included methods such as arranging multiple single-function machines as a line, or arranging a dedicated machine tool for special machining of workpieces. In addition to disadvantages such as the required floor space of the machine becoming larger and the setup work becoming longer, especially when multiple machines are arranged, the workpiece must be removed from the chuck each time to move it to the next process. I had to check again. Therefore, there have been disadvantages such as difficulty in grasping particularly complex-shaped parts and thin-walled workpieces, and difficulty in maintaining high-precision machining. In addition, in this type of machine, if the operation of attaching and detaching the workpiece to and from the chuck is automatic, it is generally carried out by a dedicated autoloader provided independently from the machine body maintenance.

This caused problems in terms of maintenance, such as the line configuration becoming complex and the number of maintenance points increasing. Furthermore, equipment such as dedicated machine tools is generally expensive and has the disadvantage of lacking in versatility.

The present invention is applied to a machine shogi machine that eliminates the above-mentioned conventional drawbacks, and is configured for the following purposes.

That is, its purpose is to provide a fastening rod that is removably provided at the tip of the spindle and engages with a fastened body (chuck) and is movable in the axial direction of the spindle, and a fastening rod that is provided at the rear of the spindle to be rotatable together with the spindle. The first
a cylinder, a first piston located in the first cylinder and connected to the fastening rod so as to be slidable in the axial direction of the main shaft; and an outer periphery of the fastening rod that is biased in the axial direction by a spring. a cylindrical body provided with
between the cylindrical body and the first piston;
an engagement piece whose axial movement is restricted so as to press against the cylindrical body and move the fastening rod in the axial direction to overcome the biasing force of the spring and prompt the fastening operation; a second cylinder disposed concentrically with the first cylinder and rotatable together with the main shaft; and a second cylinder disposed within the second cylinder so as to be slidable in the axial direction of the main shaft.
The first piston is operated to perform an attachment/detachment stroke for the object to be fastened, and the second piston is operated to perform a fastening operation for the object to be fastened. Therefore, it is an object of the present invention to provide a fastening device for a machine tool that is capable of increasing the fastening force and is safe and prevents objects to be fastened from falling off even in the event of an unexpected accident such as a power outage.

Next, an example in which the present invention is applied to a machine tool having an embodiment thereof will be described in detail with reference to the drawings, including the configuration of the machine tool. 1 and 2 show the overall configuration of a machine tool to which this embodiment is applied. A headstock 2 is placed on the bed 1 and is firmly fixed to the bed 1. In the headstock 2, a second main shaft 4 is rotatably supported parallel to a first main shaft 3.
A chuck fastened body (described later) is attached to the end of each of the main shafts 3, 4 via a joint.

The first spindle 3 driving motor 5 and the second
Motors 6 for driving the main shaft 4 are arranged at the front and rear of the bed 1 (FIG. 1). Each of the main shafts 3 and 4 is connected to each transmission mechanism 7 by a respective motor 5 and 6.
8 and up to the main shaft are driven via a belt 9. The transmission mechanisms 7 and 8 are symmetrically mounted on the bed, and motors 5 and 6 are fixed to the end faces of the boxes. A box 10 is placed on the headstock 2.
An automatic chuck exchange device 11 is provided in the box 10 so as to be rotatable with respect to the box 10.
The rotating member of the automatic chuck changing device 11 has a face plate 12 and a holding portion 14 for holding a chuck 13 on the face plate 12.

When replacing the chuck, the face plate 12 of the automatic chuck changing device 11 holds the chuck 13 in the holding part 14, and when it rotates in a direction perpendicular to the spindle axis and is indexed to a predetermined position, it can be replaced with another chuck. In this state, the chuck is tied to the main shafts 3 and 4.

On the other hand, the chuck indexed outside the processing area (located above the main spindle) is engaged with the chuck pull-out device 15 provided in the box 10 and positioned.

Subsequently, the chuck engaged with the chuck pull-out device is pulled out forward, ie, to the position indicated by the dashed double-dashed line 17 in the right direction in FIG. The workpiece is removed or inserted into the chuck pulled out to this position. Pulling the chuck forward means moving closer to the operator, so workpiece attachment/detachment operations can be performed extremely efficiently and easily.

A tightening/loosening device 18 for closing the jaws of the chuck and gripping the workpiece is attached to the end face of the box 10 provided on the headstock 2. A driver 19 is inserted into the fastening device 18 and is rotatable and can be freely moved in and out, and is provided facing the outer peripheral surface of the chuck. The chuck used in this embodiment is a scroll chuck, and a device for tightening and loosening the scroll chuck has already been described in detail in Japanese Patent Publication No. 39-3747. Since the tightening/loosening device 18 is provided outside the machining area, even when a workpiece is being machined, another workpiece can be inserted into the chuck and the workpiece can be held in the chuck by the operation of the driver 19 and then stand by. Is possible. Therefore, when the automatic chuck change is carried out again, it can immediately be inserted into the machining area as a new workpiece to be machined. Furthermore, if a workpiece that has been processed is also indexed out of the processing area, it can be removed even if other workpieces are being processed.

As mentioned above, the chuck is a scroll-shaped chuck, and the opening/closing operation of the claws of the chuck is performed by rotating a bevel gear inserted into a hole provided on the outer periphery of the chuck with the driver 19, and thus interlocking with the bevel gear. By rotating the scroll, the pawl engaged with the scroll is moved in and out of the center of rotation.

The structure of this scroll-shaped chuck is based on known chucks in common use.

Next, in the upper part of the bed 1, a guide part 1c having two sliding surfaces 1a and 1b corresponding to the above-mentioned 3 is provided. The sliding surfaces 1a, 1b are provided parallel to the spindle axis, and a saddle 2 is placed on the sliding surfaces 1a, 1b.
0 is placed across the sliding indicator. The saddle 20 is provided with a sliding surface 20a that is perpendicular to the main shaft axis and has an inclined surface (downward to the right) that descends toward the main shaft with respect to the horizontal plane as shown in FIG. A cross slide 21 is slidably mounted on the sliding surface 20a perpendicular to the axis of the main shaft. Here, the cross slide 21 is driven by a servo motor 22 via a feed gear box 23 and a ball screw.

The saddle 20 is also driven in the same manner as the cross slide 24 by a servo motor and a feed gearbox/ball screw provided at the rear of the headstock (left side in FIG. 1). The configuration of this drive system is based on a known method commonly used in commonly seen NC lathes.

A tool rest 24 is mounted on the cross slide 21, and a plurality of tools 25 (an outer diameter cutting tool and an inner diameter cutting tool) attached to a turret are arranged radially on the tool rest 24. This tool 25 is configured to be arbitrarily selected and indexed to a machining position. The details of the construction of the tool rest 24 are explained in detail in Japanese Patent Application No. 51-158646 by the same applicant, and will therefore be omitted here. The configuration explained above is the second
Although the sliding body and the turret 24 on the left side of the figure have been described, the structure and operation of the sliding body and the turret 24' on the right side are basically opposite to those on the left side.

That is, a guide portion 1c' having two sliding surfaces 1a' and 1b' is provided in the upper part of the bed 1 in correspondence with the main shaft 4, and the sliding surfaces 1a' and 1b' are provided parallel to the main shaft axis. A saddle 20' is slidably placed on the upper surface of the saddle 20'. The saddle 20' has a sliding surface 20a' that is perpendicular to the main shaft axis and has an inclined surface (downward to the left) toward the main shaft with respect to the horizontal plane as shown in FIG. cross slide 2
1' is slidably mounted perpendicular to the spindle axis.

The cross slide 21' is driven by a servo motor 2.
2' via a feed gearbox 23' and a ball screw. Further, the saddle 20' is also driven by an independently provided drive system as in the case of the saddle 20 described above.

Further, the structure of the tool rest 24' is also opposite to the above-mentioned tool rest 24, and operates in the same manner.

Due to the above configuration, each of the tool movements 24 and 24' can operate independently, and can cope with mutually different cycle operations, and the tool post's mechanical correction can also be performed independently. The configuration is such that it can be performed.

Next, the main shaft structure of a machine tool to which the present invention is applied will be explained with reference to FIG.

Main shafts 3 and 4 are supported by bearings 26 and 27 and are rotatably built into the headstock 2. As shown in FIG. The outer race of the bearing 26 is held by a snap spring 28 and a retainer 29, and is attached to the head stock 2.
is fixed. Further, the inner race of the bearing 26 is held between a collar 30 and a collar 31 and fixed to the main shaft 3. Further, the collar 31 is fixed by a nut 32 screwed onto the main shaft 3 in the axial direction of the main shaft, which is keyed together with a gear 33 that rotationally drives the main shaft 3. A joint 34 having a plurality of teeth in the circumferential direction of the end surface is bolted to the end surface of the main shaft 3.

On the other hand, the joint 3 on the main shaft 3 side is also connected to the end face of the chuck 13.
A joint 35 having teeth on the end face is bolted to engage with the chuck 4, and when the chuck 13 is pulled toward the main shaft, the meshing relationship is maintained and the main shaft 3 and the chuck 13 are connected to each other.
I am trying to become one with them. Each of the joints 34 and 35 has a toothed portion having peaks and valleys on the end face, and the peaks and valleys face each other and engage with each other, so that the joints 34 and 35 are firmly connected to the main shaft 3 without shifting in the circumferential direction. The chuck 13 is fastened. The meshing relationship between the two joints has a correlation depending on the number of teeth, and is configured to allow angular positioning within a determined range. Further, the chuck-side joint 35 is provided at exactly the same position with respect to other chucks to be replaced, and is compatible with the main shaft 3 and other chucks so that they can be easily attached and detached. A thin sleeve 36 is fitted and fixed on the outer periphery of the joint 35.

The sleeve 36 also covers the outer periphery of the chuck 13, and the sleeve 36 is adapted to fit into a grip hole 37 in the face plate 12 of the chuck exchanger when the chuck 13 moves away from the main shaft side and enters a conveyance operation. . Further, the end surface of the sleeve 36 on the working area side forms a labyrinth structure between the chuck 13 and the chuck exchanger when the chuck 13 is fastened to the main shaft 3 to prevent external chips, coolant, etc. from entering the inside. Next, a hook member 38 is attached to the end surface of the chuck 13.
is attached, and the engaging member 39 is screwed and fixed to the shaft 40 by engaging with a T-groove provided at the tip of the hook member 38.

The engaging member 39 engages with the hook member 38 and is movable in and out of the shaft 40 in the direction of the main shaft axis. The shaft 40 is guided inside the main shaft 3 by a sleeve 42 which is axially clamped and fixed inside the main shaft 3 by a snap spring 41, and a cylinder 44 is attached to the rear of the shaft 40 and biased by a disc spring 43. ing. The cylindrical body 44 has a small diameter on the main shaft side, and a large diameter part on the rear part, into which the disc spring 43 is inserted so as to straddle the shaft 40. An inclined surface is formed between the small diameter portion and the large diameter portion, and a plurality of balls 45 come into contact therewith. A plurality of disc springs 43 inserted into the cylindrical body 44 have one end in contact with the stepped surface of the cylindrical body 44, and the other end in contact with the stepped surface of the shaft 4.
The shaft 46 is pressed against the end surface of a shaft 46 which is threadedly connected to the tip of the shaft 46. Therefore, the tube supports 4, 4 are normally biased by the disk spring 43 to come into contact with the stepped shoulder surface of the shaft 40. On the other hand, an adapter 47 is keyed to the rear end of the main shaft 3.
Furthermore, it is fixed in the axial direction with a nut 48.

A second adapter 49 is further attached to the adapter 47, and the second adapter 49
A second cylinder 50 is attached to the. A second piston 51 is fitted into the cylinder 50 so as to be slidable in the axial direction, and the piston 51 is fitted into and slid into the small diameter portion of the second adapter 49. Further, the adapter 49 has a plurality of holes drilled in the radial direction, into which balls 45 are inserted. As described above, the ball 45 contacts the cylindrical body 44 along the inclined surface and also contacts the inner wall surface 52 of the hole of the second piston 51, and the ball 45 moves in and out in the radial direction according to the sliding movement of the piston 51. It is becoming possible to do so. Said second cylinder 50
A cover 53 is attached to the end face of. Therefore, a second piston 51 is disposed within the cylinder 50.
The oil chambers 54 and 55 are sandwiched between the two. A third adapter 56 is attached to the cover 53, and a first cylinder 57 is attached to the adapter 56. A first piston 58 is inserted into the cylinder 57 and is slidably guided in the axial direction across the adapter 57 and the adapter 56 . Further, the piston 58 is fitted into the shaft 46 and has one end attached to the shaft 46.
It is fixed by a nut 59 screwed into.
Oil chambers 60 and 61 are formed in the first cylinder 57, sandwiching the first piston 58 therebetween.
Further, a bracket 6 is provided on the outer periphery of the cylinder 57.
2 is inserted, and the bracket 62 is supported on the fixed side. The cylinder 57 is rotatably inserted into and supported by the bracket 6. That is, an oil passage is provided from a hydraulic power source installed on the stationary side, through this bracket 62, and further to the cylinder 57, so that pressure oil is guided to the oil chamber 54 or the oil chamber 55.

On the other hand, a disc-shaped plate 63 is fixed on the main shaft near the rear wall of the headstock. The plate 63 is for positioning the main shaft 3 at a fixed angle, and has a groove 64 cut out at one place on the circumference, and the roller 65 engages with this groove 64 when a cylinder device attached to the side wall of the headstock 2 is inserted or removed. It's starting to match. The cylinder device has a cylinder 66 fixed to the side wall and a piston 6 inside.
7 is inserted to form oil chambers 69 and 70 in the front and back in the direction of movement. Rod portion 68 of the piston 67
The roller 65 is provided through a pin.

Therefore, if pressure oil enters the oil chamber 6, the piston 6
7 moves forward with respect to the plate 63, and the roller 65 is pressed onto the circumference of the plate 63. When the main shaft 3 rotates at a low speed and the groove 64 on the plate 63 coincides with the roller position, the roller 65 engages with the groove 64 and receives a signal from this movement to stop the rotation of the main shaft 3. . Also, 70 of the oil chamber
Pressure oil is sent to the roller 65, thereby separating the roller 65 from the groove 64 of the plate 63 and allowing the main shaft 3 to start rotating again.

The spindle structure of the machine tool to which this embodiment is applied is constructed as described above and operates as follows.

When the chuck is replaced after machining of the workpiece is completed, first, the spindle 3 is indexed to a fixed position by the operation of the cylinder 66, and then pressure oil is supplied to the oil chamber 54. That is, the second piston 51 is moved to the right and the cylindrical body 4
The ball 45 engaged with the inclined surface 4 is released to the outside to release the locked state. Therefore, the cylindrical body 44
Since the second piston 58 is disengaged from the adapter 49, pressurized oil is subsequently supplied to the oil chamber 61 and the second piston 58 is moved to the left. That is, the engagement member 39
performs the forward movement while being engaged with the hook member 38 fixed to the chuck 13. At the forward end of the chuck 13, the large diameter portion of a sleeve 36 attached over the outer periphery of the chuck fits into the grip hole 37 of the face plate 12 of the chuck exchanger.

FIG. 4 shows this relationship. The hook member 38 has a T-shaped groove at its tip, and the engaging member 39 engages with the groove. Further, the engaging member 3
9 also engages with a guide piece 71 fixed to the main shaft 3, and maintains the position of the engaging member 39 so as not to shift in the rotational direction with respect to the main shaft 3.

The engagement member 39 always maintains an engagement relationship with the guide piece 71, and holds the chuck always in the same direction when the engagement member 39 is moved in and out. As described above, the chuck fitted into the gripping hole 37 of the chuck exchanging device is rotated, and another chuck is replaced and positioned at the position of the main shaft 3.

During the rotation, the hook member 38 attached to the end of the chuck moves in the rotational direction along the engagement member 39 and leaves the engagement member 39, and the hook member 38 attached to the headstock 2 and the box 10 moves in the rotational direction. Guided by rail 72. The direction of the hook member 38 is regulated and the hook member 38 is attached to the guide rail 72.
The direction of the chuck always remains constant.

A hook member fixed to the end face of another chuck rotated by the chuck exchanger with respect to the main shaft 3 engages with the engaging member 39 on the main shaft 3 side and is positioned. Next, when pressure oil is sent to the oil chamber 60, the first piston 58 moves to the right, and the engaging member 39 is drawn together with the chuck toward the main shaft, and the chuck and the main shaft are integrated through the joint. Ru. Subsequently, when pressure oil is sent to the oil chamber 55, the second piston 51 moves to the left, and the ball 45 is pressed inward along the inclined surface, and the cylindrical member 44 engaged with the ball 45 is pressed against the ball 45. The chuck is pushed to the right by overcoming the restoring force of the disc spring 43, and the chuck is strongly fastened to the main shaft. Therefore, even if pressure oil is not normally supplied due to an unexpected accident, the structure is designed with safety in mind so that the fastened state will not be released and the chuck will not separate from the main shaft.

Next, FIG. 5 is a view showing the relationship between the main shaft and the inner rail from the working area side, and shows the arrangement of the shafts 3, 4 and pull-out devices 15, 15' (described later) for chuck exchange. Further, the chuck exchanger and the rotating shaft 73 are rotated between each of the main shafts and each of the drawer devices. Also, along this rotation direction, each main shaft 3, 4 and each puller device 1
5 and 15' is an arcuate guide rail 72.
A, 72B, 72C, and 72D are arranged.

Therefore, the chuck is held by the chuck exchanger and moved around the guide rail 72 about the rotation shaft 73.
It is rotated while maintaining a constant orientation along the When the chuck leaves the main shafts 3 and 4, the pull-out devices 15 and 15'
A drive device 16 is provided above the rotation shaft 73 for pulling out the chuck toward the operator when the chuck is indexed to the position. FIG. 6 is a developed cross-sectional view of FIG. 5 showing details of the rotating part of the chuck exchanger and the drawer.

A plate 76 is attached to the tip of the piston rod 75 of the drive device 16, ie, the cylinder device 74, for drawing out the chuck. One end of the plate 76 is fixed to the rear end of the cylindrical bar 77 of the chuck extractor 15, 15'. The other end of the plate 76 engages with a shifter rod 78 for engaging and unlatching the rotating portion of the chuck exchanger. The shifter rod 78
is provided to be able to be taken in and out of the box 10, and a shifter fork 79 is attached to one end inside the box 10. The shifter fork 79 is inserted into a groove 81 formed in a ring shape along the circumference of a pinion gear 80 that is slidably fitted into the spline portion 73' of the rotation shaft 73 of the chuck exchanger. ing. The cylindrical bar 77 of the drawer device 15 is connected to the box 10.
A bracket 82 is attached to one end of the bar 77 on the working area side. The bracket 82 is provided with a stepped hole into which the hook member 38 can be inserted, and a locking piece 83 is attached to the end surface of the hole to prevent the hook member 38 from turning when inserted. Two metals 84 are provided within the cylinder cleaning bar 77, and a rod 85 is supported by the metals 84 and is provided so as to be freely movable in and out in the axial direction. A locking member 39 is attached to one end of the rod 85, and a collar 86 is attached to the other end, and a plurality of disc springs 87 are inserted between the collar and the plate 76. Further, a stopper 88 is provided on the fixed side behind the rod 85 so as to allow free axial adjustment. The drawer device is constructed as described above,
It works like this: That is, when replacing the chuck, the bar 77 is retracted to the rear, but in this case the plate 76 is moved to the rear of the main shaft by the operation of the cylinder 74. Since the plate 76 and the bar 77 are integrated, the bar 77 is retracted to a predetermined position. During this operation, the rod 85
The bar 77 comes into contact with the stopper 88 and stops the backward movement in the axial direction, but the bar 77 and the plate 76 overcome the restoring force of the disc spring 87 and still move backward, causing the bracket 82 to separate from the hook member 39 and the chuck to rotate. positioned in a movable position.
When the chuck is indexed and positioned in engagement with the bracket 82 of the extractor 15, the extractor holds the chuck by the action of the cylinder 74 and draws it forward (leftward) to the workpiece loading/unloading position. This operation occurs because first, as the plate 76 moves forward, the rod 85 is urged outwardly with respect to the plate 76 by the disc spring 7, so as the bar 77 moves forward, the racket 82 first becomes attached to the chuck hook member. 3. The hook member 39 and the bracket 82 are engaged and prevented from rotating, and continue to move forward and are positioned at a predetermined position. When the attachment/detachment operation of the workpiece is completed, the bar 77 performs the opposite operation to that described above, and maintains the state shown in FIG. 6 during chuck exchange.

Next, the rotation device of the chuck exchanger will be explained. The rotating shaft 73 is rotatably supported by the box 10, and has a spline 73' in the center.

A face plate 12 is fixed to the working area of the rotation shaft 73. The face plate 12 has four grips 37 through which chucks can be inserted and removed as described above. In addition, the spratton portion 73' of the rotation shaft 73
A sleeve-shaped pinion gear 80 is fitted into the shaft so as to be movable in the axial direction. The pinion gear 80 is in a meshing relationship with a rack 89, and is engaged and removed by the operation of the shifter fork 79. This meshing operation is performed as follows. When the pinion 80 is released from the rack 89 from the engaged state as shown in FIG.
The plate 76 moves forward until it comes into contact with the stepped portion 78' of the shifter rod 78. Subsequently, when the chuck, in which the plate 76 is maintained in contact with the stepped portion 78' and the shifter rod 78 is also advanced together, is positioned at the workpiece attachment/detachment setting position, the pinion gear 80 is brought into contact with the rack 89. This means that the mesh is out of alignment.

Chuck forward stroke and pinion gear 8
The configuration has different strokes for engagement and disengagement, and each stroke is limited to the required stroke.

The structure and operation of the rack 89 are as follows.

A piston 91 fitted into a cylinder 90 is provided at both ends of a clamping body 92, and the central part of the clamping body 92 constitutes the rack 89, and the stepped portion 92
A' and 92B are provided. Also, the cylinder 9
A cover 93 is attached to one end of the 0, and a stopper 94 is attached to the cover 93 in an adjustable manner so as to come into contact with the protrusion 92C of the clamping body 92. On the other hand, a locking body 95 is attached to the side wall of the cylinder 90 so as to be able to engage with and disengage from the stepped portions 92A and 92B. The state shown in FIG. 7 shows the state in which the rack 89 is disengaged from the pinion gear 80 while the pull-out device 15 is loading and unloading the workpiece, and the chuck changing device has returned to the position where it can be indexed by 90 degrees. There is. Therefore, the cylinder 74 operates again and the drawing device 15
When the retraction chuck is inserted into the hole 37 of the face plate 12, the pinion gear 80 is also engaged with the rack 89 again by the shifter fork 81, and when the replacement device is indexed 90 degrees next time, pressure oil is sent to the oil chamber 96. The rack 89 is moved rightward until the protrusion 92C of the clamping body 92 comes into contact with the stopper 94. When the rack 91 is to be returned, when the pinion gear 80 is disengaged from the rack 89, pressurized oil is supplied to the oil chamber 97 and the rack 89 is moved until the stepped portion 92A comes into contact with the engaging body 95. The rotating operation of the chuck exchanger may be repeated as described above. Further, when performing a 180 degree indexing operation, the engaging body 95 may be retracted so as to come into contact with the stepped portion 92B.

Also, although not shown, limit switches and the like are arranged to confirm the positioning of each operation and exchange signals.

A machine tool to which the present invention is applied is constructed as described above, and by utilizing the present invention in the machine tool, the chuck can be attached to and detached from the main shaft, and the fastening operation can be performed, so that the chuck can be attached to the main shaft. However, it can be fastened strongly and reliably. Due to the above-mentioned configuration of the fastening device, even if an unexpected accident such as a power outage occurs, there is no risk of the chuck falling off from the main shaft, and the fastening device has been designed with safety in mind. The present invention is applicable not only to the machine tools of the embodiments but also to the spindles of machine tools such as machining centers.

As described above, the present invention is not limited to the configurations shown in the embodiments, and modifications are expected without departing from the technical idea of the present invention as described in the claims.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the overall configuration of a machine tool to which the present invention is applied, FIG. 2 is a side view similarly showing the overall configuration, and FIG. Figure 4 is a partial view of the main shaft configuration showing where the chuck has moved relative to Figure 3;
The figure is a partial diagram showing the relationship between the main shaft and the pull-out device.
FIG. 6 is a sectional view showing a drawing device, and FIG. 7 is a sectional view showing a chuck rotation drive device for a machine tool to which the present invention is applied. In the figure, 1... bed, 2... head stock, 3, 4... main shaft, 11... automatic chuck exchange device, 13... chuck, 15... chuck drawer device, 20, 20'... saddle, 21, 2
1'...Cross slide, 24, 24'...Turret, 34, 35...Joint, 45...Ball, 50
... second cylinder, 51 ... second piston, 57 ... first cylinder, 58 ... first piston, 73 ... rotating shaft, 92 ... cylinder.

Claims (1)

[Claims] 1. In a machine tool having a bed, a headstock placed on the bed, and a spindle rotatably incorporated in the headstock, a fastened body detachably provided at the tip of the spindle, and the fastened body a fastening rod extending in the axial direction of the main shaft so as to be engaged with the main shaft and movable in the axial direction of the main shaft; a first cylinder provided at the rear of the main shaft so as to be rotatable together with the main shaft;
The fastening rod is integrally connected within the first cylinder and can be stroked in the direction of the main shaft axis between two positions: a fastening position at the tip of the main shaft of the fastened body and a replacement position in front of the main shaft of the fastened body. A second cylinder, which is provided within the second cylinder and is slidable in the axial direction of the main shaft, includes a first piston provided therein, and a second cylinder that is arranged concentrically with the first cylinder and rotatable together with the main shaft. a cylindrical body provided on the outer periphery of the fastening rod and having an inclined surface; a spring that is interposed between the cylindrical body and the fastening rod and biases the cylindrical body in the axial direction of the main axis of the cylinder; between the second pistons, the movement of the second piston in the direction of the main shaft axis presses the fastening rod against the inclined surface of the cylindrical body, and the fastening rod is moved in the direction of the main shaft axis, overcoming the biasing force of the spring and performing a retightening fastening operation; The movement of the first piston is the movement of the first piston, and the movement of the second piston is the movement of the second piston. A fastening device for a machine tool characterized by performing an integrated action of retightening and fastening the body.