JP6767779B2 - Chuck device and work chuck method - Google Patents

Description

The present invention relates to a chuck device including a first chuck mechanism located on the outside away from the rotation center of the spindle and a second chuck mechanism located on the inside near the rotation center of the spindle, and a work chuck method using the chuck device. Regarding.
Regarding.

In machine tools and the like, a chuck device is used as a configuration for setting a workpiece to be machined on a spindle. As for such a chuck device, for example, a floating chuck mechanism has been proposed as a means for absorbing the misalignment between the center of rotation of the spindle and the center of the clamped work. Patent Document 1 below proposes a configuration in which a chuck device can be slid in a direction orthogonal to the center line of the spindle by attaching a chuck device to the spindle via a floating member. According to this floating chuck mechanism, when the floating member is displaced, the chuck device is automatically centered and the deviation can be absorbed.

Japanese Unexamined Patent Publication No. 2008-2466332

However, in such a conventional spindle chuck structure, since the floating member is arranged so as to be sandwiched between the chuck device and the spindle, the power for clamping the work with respect to the chuck device is transmitted from the spindle side. The problem is how to configure the transmission mechanism of. Further, in a configuration in which the floating member is sandwiched between the chuck device and the spindle, the rigidity of the portion is lowered, and the machining accuracy may not be improved. Further, the addition of a new floating member may not only increase the number of parts and increase the cost, but also increase the burden of maintenance and replacement of parts due to life or damage.

Therefore, an object of the present invention is to provide a chuck device having a floating mechanism inside and a work chuck method using the chuck device in order to solve such a problem.

The chuck device according to the present invention includes a first chuck mechanism arranged on the outside away from the rotation center of the spindle and a second chuck mechanism arranged on the inside close to the rotation center of the spindle, with respect to the rotating spindle. The first chuck mechanism clamps the work in accordance with a reference position, and the second chuck mechanism is for a base member fixed to the rotation shaft side. Assembled in a floating state with a gap in the radial direction, the work is clamped according to the clamp position by the first chuck mechanism, and is connected to a drawbar and is a tubular collet member that can move in the axial direction. The collet member is provided with a guide member arranged outside the collet member and the tapered surfaces are in sliding contact with each other, and the work is clamped by the inward deformation of the collet member, and the guide member is attached to the base member. It is attached by a mounting member so as to create a radial gap .

According to the present invention, after the work is clamped to the reference position in the first chuck mechanism, the work is clamped at the position displaced according to the positioned work in the second chuck mechanism assembled in the floating state. be able to.

It is sectional drawing which showed the spindle device. It is sectional drawing which showed one Embodiment of a chuck device. It is a simplified view which showed the clamp state of a work from the front side. It is sectional drawing which showed the 1st chuck mechanism enlarged. It is a partially enlarged sectional view of the floating structure in the 2nd chuck mechanism. It is a partially enlarged sectional view of the floating structure in the 2nd chuck mechanism.

Next, an embodiment of the chuck device and the work chuck method according to the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing a spindle device. The spindle device 1 constitutes a spindle of a machine tool, and a chuck device 5 for clamping a work is provided at a tip portion thereof. In the spindle device 1, the spindle 12 is rotatably assembled in the cylindrical spindle base 11, and the chuck device 5 is attached to the tip of the spindle 12.

A pulley 13 is fixed to the spindle 12, and a belt 14 is hung between the pulley and a pulley fixed to a rotating shaft of a spindle motor (not shown). Further, the spindle 12 is provided with an encoder (not shown) for detecting the rotation speed, and a timing belt 16 is also hung between the pulley 15 fixed to the spindle 12 and the pulley on the encoder side. Has been done. Therefore, the rotation is transmitted from the rotation-controlled spindle motor to the chuck device 5 via the spindle 12, and the clamped workpiece is given rotation during machining.

Further, a tubular first draw bar 17 and a second draw bar 18 are inserted in a double manner inside the spindle 12, and a telescopic actuator for driving the chuck device 5 is provided for each of them. In the present embodiment, a hydraulic cylinder is used as the telescopic actuator, the piston of the first cylinder 21 is integrally formed on the first drawbar 17, and the piston of the second cylinder 22 is integrally formed on the second drawbar 18. There is. Therefore, due to the supply and drainage of the hydraulic oil performed via the inducer 23, the first cylinder 21 and the second cylinder 22 operate independently in the axial direction (XR direction and XL direction), and the first drawbar Output to the chuck device 5 is performed via the 17 and the second drawbar 18.

The second drawbar 18 penetrates the second cylinder 22 in the axial direction and extends to the inducer 24 on the rear side (XL side) of the spindle device 1. An air pipe 19 is inserted inside the second drawbar 18, compressed air is supplied into the air pipe 19 from the first port 241 of the inducer 24, and a cylinder between the second drawbar 18 and the air pipe 19 is provided. The coolant liquid is supplied to the space from the second port 242. Therefore, the compressed air and the coolant liquid are sent to the chuck device 5 through the flow path of the axial center portion, respectively.

Next, FIG. 2 is a cross-sectional view showing the chuck device of the present embodiment. Further, FIG. 3 is a simplified view showing the clamped state of the work from the front side (right side of FIG. 2). The chuck device 5 includes a first chuck mechanism 7 that executes clamping by the output of the first cylinder 21 and a second chuck mechanism 8 that executes clamping by the output of the second cylinder 22 for one work W. are doing. Note that FIG. 3 shows the first chuck mechanism 7.

In the chuck device 5, the base member 31 is fixed to the spindle 12, and the first chuck mechanism 7 and the second chuck mechanism 8 are integrally assembled with the rotating base member 31. In the first chuck mechanism 7, a cylindrical first transmission member 32 is fixed to the first drawbar 17 by screwing a screw portion, penetrates a bearing member 33 fixed to the spindle 12, and is slidably supported. ing. An arm member 34 is connected to the first transmission member 32, and an operation shaft 35 is connected to the tip end portion thereof. As shown in FIG. 3, in the first chuck mechanism 7, three top jaws 40 serve as clamp claws to face-clamp the work W. Therefore, the arm member 34 has three operating shafts 35, respectively. It is connected to the position.

A rotating shaft 36 is connected to the operating shaft 35. On the other hand, the support member 41 is fixed to the base member 31, and the case member 38 that holds the rotating shaft 36 is fixed to the support member 41. The rotary shaft 36 slidably inserted into the insertion hole of the case member 38 has one end side formed in a tubular shape, and the operation shaft 35 is inserted therein so that the two shafts are coaxially overlapped. Then, the pin 37 penetrates the overlapping portion in the radial direction to connect the operation shaft 35 and the rotation shaft 36, but a lead groove 361 cut diagonally with respect to the axis is formed on the rotation shaft 36 side. When the operating shaft 35 is displaced in the axial direction, the pin 37 fixed to the operating shaft 35 side moves in the lead groove 361.

Further, a spring 39 is inserted inside the rotating shaft 36, and an elastic force acts in the axial direction between the rotating shaft 36 and the operating shaft 35. A top jaw 40 for clamping the work W is fixed to the end of the rotating shaft 36. Therefore, in the first chuck mechanism 7, the operating shaft 35 moves in the axial direction (XR direction and XL direction), so that the rotating shaft 36 rotates so as to be pushed by the pin 37 moving in the lead groove 361. Then, the top jaw 40 is given a turn as shown in FIG. 3 as it moves in the axial direction. As a result, the work W is clamped and unclamped by the top jaw 40 applied from the front side (right side in the drawing).

In the present embodiment, since the top jaw 40 is pressed against the work W from the front side, the winning amount 43 is arranged on the back side thereof. A positioning pin 44 is formed on the winning amount 43. As shown in FIG. 3, since the work W has a complicated shape, a positioning hole Wh for assembly is formed as a reference position when assembling as a component. Therefore, even during machining in a machine tool, the positioning hole Wh is used as a reference position at the time of clamping, and the positioning pin 44 formed in the money 43 is inserted into the positioning hole Wh. Therefore, the clamp of the work W by the first chuck mechanism 7 determines the reference position of the work W at the time of machining.

In addition to the first chuck mechanism 7, the chuck device 5 is provided with a second chuck mechanism 8 that clamps the work W inside near the center of rotation of the spindle in order to eliminate chattering and the like generated during machining and stabilize the work W. Has been done. However, if the respective clamps performed by the two chuck mechanisms are misaligned, the force applied by both clamps may deform the work W and reduce the machining accuracy. Therefore, in the present embodiment, the work is positioned at the reference position by the first chuck mechanism 7, and the second chuck mechanism 8 is configured to follow the positioning.

FIG. 4 is an enlarged cross-sectional view showing a portion of the second chuck mechanism 8. In the second chuck mechanism 8, a cylindrical second transmission member 51 is connected to the second drawbar 18, and the second transmission member 51 is slidably supported through the central portion of the second support member 41. Has been done. A collet member 55 is attached to the second transmission member 51 by a connecting member 56. The connecting member 56 is fastened to the second transmission member 51 by a screw portion, and the inner flange of the collet member 55 is sandwiched in the annular groove formed between the connecting member 56 and the second transmission member 51. It is assembled in this way. Therefore, the collet member 55 is configured to move in the axial direction according to the second draw bar-18.

The collet member 55 has a guide member 53 on the outer side in the radial direction and a clamp member 57 on the inner side. Since the collet member 55 and the guide member 53 are in contact with each other via a tapered surface, the collet member 55 is pulled in the XL direction, so that the collet member 55 is bent toward the center of rotation, that is, inward in the radial direction. .. Then, the inner clamp member 57 is pushed by the bent collet member 55, and the clamp that grips the work W so as to wrap it is performed. On the other hand, when the collet member 55 is pushed in the XR direction, unclamping is performed to release the work W from the clamp member 57.

A base member 52 is fixed to the support member 41 by fastening bolts, a stripper bolt 61 is fastened to the base member 52, and a guide member 53 is attached to the base member 52 by the stripper bolt 61. The mounting hole 531 of the guide member 53 is formed so as to form a gap between the guide member 53 and the stripper bolt 61. Further, the guide member 53 is fitted in the recess 521 of the base member 52, but since there is a gap here as well, the guide member 53 is attached in a state where it can be displaced with respect to the base member 52. That is, the guide member 53 is assembled to the base member 52 in a floating state.

A clamp member 57 is fastened to the guide member 53 by bolts 62 to be integrated. A collet member 55 is arranged and integrally formed between the guide member 53 and the clamp member 57, but a slidable bush 63 is fitted in a through hole through which the bolt 62 passes, and the collet member 55 is formed. , The structure is such that the guide member 53 and the clamp member 57 can be displaced in the axial direction. Therefore, the collet member 55 is displaced in the axial direction with respect to the clamp member 57 that does not change in the axial direction, so that the above-mentioned work W is clamped and unclamped.

The clamp member 57 is also fitted into the connecting member 56 to form an integral structure. Further, a support member 58 for positioning the work W is screwed to the inner side of the cylindrical clamp member 57. The support member 58 holds the unstable work W in the previous stage of being clamped by the clamp member 57 and the first chuck mechanism 7 in the chuck device 5. Inside the cylindrical support member 58, a coolant flow path 65 composed of a second transmission member 51, a connecting member 56, a clamp member 57, and a through hole formed in the support member 58 is configured. A coolant flow path 66 is also formed on the first chuck mechanism 7 side. Therefore, the coolant liquid sent through the second drawbar 18 is sprayed onto the work W through the coolant flow paths 65 and 66.

Subsequently, the work W is clamped and unclamped in the chuck device 5 as follows. First, the work W is positioned so that the protrusion Wa is inserted into the support member 58 at the center of rotation of the spindle and the position determination pin 44 is inserted into the position determination hole Wh so that the work W is applied to the deposit 43. Will be Then, when the work W is chucked, the clamping in the first chuck mechanism 7 is performed first, and then the clamping in the second chuck mechanism 8 is performed.

In the clamp of the first chuck mechanism 7, the first drawbar 17 moves in the XL direction by the operation of the first cylinder 21, and the first transmission member 32, the arm member 34, and the operation shaft 35 are pulled in the same direction in conjunction with the movement. Displace in this way. The normal top jaw 40 is at the position shown by the alternate long and short dash line in FIG. 3, but when the operation shaft 35 moves in the XL direction, the pin 37 moves in the lead groove 361, so that the rotation shaft 36 rotates and the top The jaw 40 turns to the position shown by the solid line in FIG. The tip of the top jaw 40 is located at the edge of the work W, and the top jaw 40 is displaced in the XL direction via the rotation shaft 36 to clamp the work W by pressing it from the front side.

On the other hand, when the first chuck mechanism 7 unclamps the work W, the first drawbar 17 moves in the XR direction by the operation of the first cylinder 21, and in conjunction with this, the first transmission member 32 and the arm member 34 are moved. The operation shaft 35 is displaced so as to be pushed in the same direction. Then, the pin 37 moves in the lead groove 361, and the rotation shaft 36 rotates to rotate the top jaw 40, so that the tip of the top jaw 40 moves from the position shown by the solid line in FIG. 3 to the position shown by the alternate long and short dash line. Move while moving away from work W.

Next, after the first clamp of the first chuck mechanism 7 described above, the second clamp by the second chuck mechanism 8 is performed. At that time, the centering of the second chuck mechanism 8 is performed before the clamping operation. In the centering step, rotation is given to the chuck device 5. Specifically, the spindle motor gives the spindle 12 a predetermined number of rotations for a predetermined time, and the entire chuck device 5 rotates via the base member 31 integrated with the spindle 12.

Therefore, a centrifugal force acts on the chuck device 5, and in the second chuck mechanism 8, the guide member 53, the collet member 55, the clamp member 57, and the support member 58 having a floating structure are radially inside the base member 52. It will be displaced. Therefore, even if the center position of the second chuck mechanism 8 is displaced from the center position of the protruding portion Wa of the work W in the first clamp state, the clamp member 57 and the guide member 53 that directly grip the work W However, the centering is performed so as to be displaced in the radial direction according to the position of the work W (protruding portion Wa). Then, after the centering, the second clamp is performed.

In the second clamp of the second chuck mechanism 8, the second drawbar 18 moves in the XL direction due to the operation of the second cylinder 22, and the second transmission member 51 and the collet member 55 are pulled in the same direction in conjunction with the movement. Displace. Then, the collet member 55 slides on the tapered surface in contact with the guide member 53 and is bent inward, whereby the clamp member 57 is pushed and a second clamp for gripping the work W (protruding portion Wa) is performed. .. On the other hand, when the work W is unclamped, the second drawbar 18 moves in the XR direction due to the operation of the second cylinder 22, and the second transmission member 51 and the collet member 55 are pushed in the same direction in conjunction with the movement. Displace. Then, the collet member 55 is bent back by the tapered surface in contact with the guide member 53, and the pressing of the work W by the clamp member 57 is released.

By the way, in the floating structure of the second chuck mechanism 8, the guide member 53 is attached to the base member 52 by a stripper bolt 61. In this case, the guide member 53 is provided with a gap in the radial direction, which is the centering direction, with respect to the stripper bolt 61 and the base member 52, but is in contact with the base member 52 in the axial direction. Since the centering is performed by the centrifugal force that rotates the chuck device 5, if the contact resistance between the guide member 53 and the base member 52 is large, the centering operation is hindered. Therefore, in order to reduce the contact resistance, the following configuration is effective as the second chuck mechanism 8.

5 and 6 are enlarged views of the arrow P shown in FIG. First, the first plan shown in FIG. 5 will be described. The guide member 53 is inserted into the recess 521 of the base member 52, and the end faces 533 and the bottom surface 523 facing each other in the axial direction come into contact with each other to generate contact resistance. Therefore, it is assumed that the end surface 533 of the guide member 53 has a convex portion 535 having a trapezoidal cross section formed in an annular shape along the outer edge. By reducing the contact area of the base member 52 with the bottom surface 523 in this way, the contact resistance to centrifugal force is reduced, and the guide member 53 and the like can be smoothly displaced. The convex portion 535 is not limited to the position along the outer edge of the end face 523, and may be formed on the center side.

Next, the second plan shown in FIG. 6 will be described. Here, a convex portion 537 having a trapezoidal cross section is formed in an annular shape on the end surface 533 of the guide member 53, and an annular concave portion 525 is formed on the bottom surface 523 of the base member 52 according to the position thereof. Ball 68 is inserted. Therefore, when viewed in the axial direction, the guide member 53 and the base member 52 are arranged with the end surface 533 and the bottom surface 523 via the balls 68 without being in direct contact with each other, so that the guide member 53 that moves in the radial direction can be used. Supported by the ball 68, the contact resistance becomes smaller and the centering by the centrifugal force is smoothly performed.

Therefore, in the present embodiment, after the work W is clamped by the first chuck mechanism 7, the second chuck mechanism 8 having a floating structure performs centering, so that the reference position in the clamp of the first chuck mechanism 7 is relative to the reference position. The clamp position of the second chuck mechanism 8 can be adjusted. Even if the two sets of chuck mechanisms are displaced from the reference position, the second chuck mechanism 8 side absorbs the deviation, so that the work W can be clamped and processed without applying a load. Moreover, since the chuck device 5 has a built-in floating structure, it does not increase the number of parts as a separate member as in the conventional example, and does not cause a decrease in rigidity or a structural defect of the transmission mechanism.

Further, in the floating structure of the present embodiment, the guide member 53 is attached by the stripper bolt 61 fastened to the base member 52, and a gap is provided between the stripper bolt 61 and the guide member 53. The structure is simple, and there is no need to make major design changes to the conventional chuck device. Further, since the second chuck mechanism 8 is centered by the centrifugal force that rotates the chuck device 5, no manual work is required, and only one step is added at the time of processing, and the core does not take a long time. Can be put out. Further, by adding a configuration for reducing the contact resistance as shown in FIGS. 5 and 6, the centering in the second chuck mechanism 8 can be performed more accurately.

Although one embodiment of the chuck device and the work chuck method of the present invention has been described above, the present invention is not limited to this, and various modifications can be made without departing from the gist thereof.
For example, the first chuck mechanism 7 of the embodiment comprises a face clamp chuck with a top jaw 40, but the work W is not limited to that of the embodiment, so that the first chuck mechanism is also various. A clamp structure that can be used for various workpieces is available.

Further, in the above-described embodiment, the stopper bolt 61 is used as the mounting member, and the guide member 53 is mounted on the base member 52 so as to generate a gap in the radial direction. For example, other configurations may be used.
Further, for example, the convex portions 535 and 537 shown in FIGS. 5 and 6 and the annular concave portion 525 containing the plurality of balls 68 may be configured in the opposite direction to the guide member 53 and the base member 52. ..

1 ... Spindle device 5 ... Chuck device 12 ... Spindle 17 ... 1st drawbar 18 ... 2nd drawbar 18 21 ... 1st cylinder 22 ... 2nd cylinder 35 ... Operation shaft 36 ... Rotating shaft 40 ... Top jaw 43 ... Money 44 ... Positioning pin 52 ... Base member 53 ... Guide member 55 ... Collet member 57 ... Clamp member W ... Work

Claims (5)

A chuck having a first chuck mechanism arranged on the outside away from the rotation center of the spindle and a second chuck mechanism arranged on the inside near the rotation center of the spindle to hold a work with respect to the rotating spindle. In the device
The first chuck mechanism clamps the work in accordance with the reference position.
The second chuck mechanism is assembled in a floating state with a radial gap with respect to a base member fixed to the rotating shaft side, and clamps the work in accordance with the clamping position by the first chuck mechanism. A tubular collet member that is connected to a drawbar and can move in the axial direction, and a guide member that is arranged outside the collet member and has tapered surfaces in sliding contact with each other, and is provided inside the collet member. A chuck device in which a work is clamped by deformation of the work, and the guide member is attached by an attachment member so as to form a radial gap with respect to the base member . The chuck device according to claim 1 , wherein the second chuck mechanism has a protrusion formed on one of the base member and the guide member which are in contact with each other in the axial direction. The chuck device according to claim 1 , wherein the second chuck mechanism is one in which a plurality of balls are held by one of the guide member and the base member facing in the axial direction. A deposit for arranging the work in alignment with the reference position is fixed to the base member.
The chuck according to any one of claims 1 to 3 , wherein the first chuck mechanism includes a clamping means for sandwiching and clamping a work in the axial direction with the current. apparatus. A chuck device having a first chuck mechanism arranged on the outside away from the rotation center of the spindle and a second chuck mechanism arranged on the inside near the rotation center of the spindle to hold a work with respect to the rotating spindle. It is a work chuck method,
The first clamping step of clamping the work according to the reference position by the first chuck mechanism, and
The second chuck mechanism in a floating state having a radial gap with respect to the base member assembled together with the first chuck mechanism is in an unclamped state together with the base member fixed to the rotating shaft of the spindle. A centering step in which the second chuck mechanism is rotated and a centrifugal force is applied to the second chuck mechanism.
A work chuck method comprising a second clamping step of clamping a work by the second chuck mechanism.

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