JP2009000752A - Chucking device of machine tool and method for processing inner/outer diameters of workpiece using the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chucking device for processing inner/outer diameters of an eccentric workpiece in a machine tool comprising a self-aligning mechanism, with a simple structure and capable of automatically conforming a processing center of the eccentric workpiece having an arbitrary shape to a rotation center of a spindle without any specific operation, and its processing method. <P>SOLUTION: The device comprises a retractable chuck operation member 30 on an axial line of the spindle 100 by a propulsion force generator through a penetration hole formed at the center of a chuck body 10 fixed to a front part of the spindle 100. Two or more movable members 60 moves to and away from each other in a radial direction orthogonal to the spindle based on the retractable movements of the chuck operation member. A first end part is put in resilient-contact with an outer end part of the respective movable members. Two or more clampers having chuck claws are provided at a second end part on the opposite side of the first end part. An intermediate member 40 is provided on a front end of the chuck operation member and between facing surfaces of the movable members. The intermediate member 40 itself is also capable of freely and independently moving from the axial line of the spindle to the radial direction. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention provides chucking in a machine tool capable of automatically and reliably gripping the workpiece center as a gripping center without requiring a special operation even when the workpiece center is offset from the gripping center. The present invention relates to an inner and outer diameter machining method of a workpiece using the apparatus and its chucking apparatus.

  Conventionally, when machining the inner and outer diameters of a workpiece whose machining center is offset from the gripping center with a lathe or milling machine, the workpiece peripheral surface is first gripped by multiple chuck claws so that the machining center of the workpiece is the center of rotation of the spindle. Then, rotate the spindle of the actual machine to perform trial cutting, and if there is a deviation, manually adjust the gripping position of the chuck claw and perform trial cutting again, and repeat this to match the machining center with the spindle center To determine the gripping position of the workpiece. This chuck claw positioning operation takes a long time even by skilled workers.

  In addition to these operations, for example, for a rectangular plate-shaped workpiece whose machining center is deviated from the workpiece center, one side of the side surface (grip side surface) in which the machining center position is shifted from the workpiece center position is first selected. The first gripping reference surface is cut and finished, and the point that is the design center of processing from the first gripping reference surface is determined as the center point, and the accurate gripping position of the other side surface (other gripping surface) from the center point And the excess side surface portion on the other side surface is cut to form the second gripping reference surface. Next, the chuck positioning is performed by manually adjusting the chuck claw position according to the positions of the first and second gripping reference surfaces.

  However, the adjustment of the chuck claw position by the above-described manual operation is not only complicated, but also requires a very long time. Therefore, an invention for automatically matching the gripping center with the processing center for a workpiece having a deviation between the processing center (main spindle center) and the gripping center is disclosed in, for example, Japanese Patent Laid-Open No. 64-11702 (Patent Document 1). Japanese Patent Publication No. 1-50522 (Patent Document 2), Japanese Patent Application Laid-Open No. 2005-95996 (Patent Document 3), and the like.

  In the automatic eccentric chuck disclosed in Patent Document 1, a chuck body is fixed to the front part of a spindle provided in a head stock of a lathe, and a sliding member is freely moved in the diameter direction on the front part of the chuck body. Installing as you get. A stopper for moving the sliding member to a predetermined position and stopping and a fixing means for fixing the sliding member at the stop position are provided, and an openable / closable chuck claw for gripping a workpiece on the front part of the sliding member. A chuck mechanism is provided. The chuck body is provided with operating means for moving the sliding member in the diameter direction. With such a configuration, eccentric processing at two locations can be performed in one step.

  The eccentric chuck device for a crankshaft disclosed in Patent Document 2 is a contact that is indexed in accordance with the pin stroke of the crankshaft to be machined by moving the slider and the gripping portion in the diameter direction of the main shaft by a driving device. The crankshaft is positioned and held by coming into contact with the projection, and simultaneously with this movement, the balance weight is moved and positioned in the opposite direction to the slider and the gripper via the interlocking device. It is configured so that the balance collapse according to the eccentric distance from the spindle axis of the center of gravity of the eccentric chuck device due to the movement of the slider and the gripping part in the diameter direction is not canceled and increased by the movement of the balance weight. ing.

The chuck device disclosed in Patent Literature 3 presses a plurality of chuck claw rods respectively linked to a plurality of chuck claws with a pressing member, and moves the plurality of chuck claws in the radial direction, thereby clamping a workpiece. Is configured to grip. Further, a spherical bearing is installed in the central area of the pressing member, and the pressing member is supported to be tiltable with respect to the chuck claw driving body via the spherical bearing. By supporting the pressing member in such a manner that the pressing member can be tilted, the tilting angle of the pressing member with respect to the chuck claw driving body can be made larger than that of the conventional chuck device, and thus the chuck depends on the inclination of the pressing member. The alignment amount of the device, that is, the dimensional difference from the center reference on the outer peripheral surface of the workpiece that can be gripped by a plurality of chuck claws can be greatly increased compared to the conventional chuck device. is there.
JP-A 64-11702 Japanese Patent Publication No. 1-50522 JP 2005-95996 A

  By the way, in the chuck device disclosed in Patent Document 1, since the stopper position is not fixed, the stop fixing position of the sliding member is limited to two, and the workpiece processing is limited to processing with the same eccentric amount. It will be. Moreover, each time a workpiece with a different size is required, a chuck mechanism corresponding to the workpiece size must be mounted on the sliding member.

  Further, in the chuck device disclosed in Patent Document 2, the eccentricity adjustment mechanism of the chuck device is complicated, the number of parts is large, and it must be extremely expensive. Further, in this chuck device, since the moving distance (eccentricity) of the slider is determined by the protruding lengths of a plurality of abutting protrusions protruding from the stopper mounted on the chuck body, the same as in Patent Document 1 above. The machining target and the eccentric amount are limited, and it is impossible to position the machining center with respect to different types of workpieces having an arbitrary eccentric amount.

  According to the chuck device with an alignment mechanism disclosed in Patent Document 3, each of the pressing members that has a chuck claw and presses a plurality of chuck claw rods that move the chuck claw in the contact and separation direction at the time of chucking the workpiece. By providing a spherical bearing in the center area, compared to a conventional chuck device with a centering mechanism that has a radial thrust bearing on the main shaft side of the pressing member, only a large centering amount, that is, centering for a large deviation is possible. Instead, the alignment mechanism can be made compact. However, the chuck device disclosed in Patent Document 3 has an alignment amount that is still small, and can reliably adjust a workpiece having a larger alignment amount without requiring a special operation. Realization of a chuck device that can reliably hold the core and the grip is strongly desired.

  The present invention has been made in view of such circumstances, and an alignment mechanism with a simple structure capable of automatically matching the machining center of an eccentric workpiece having an arbitrary outer shape with the rotation center of the main spindle without any special operation. It is an object of the present invention to provide a chucking device for machining the inner and outer diameters of an eccentric workpiece in a machine tool having a machining method and a machining method therefor.

  The above object is a basic structure of the present invention, which is inserted into a chuck body fixed to the front part of the spindle and a through hole formed in the center of the chuck body, and is advanced and retracted on the axis of the spindle by a propulsion generator. A possible chuck operating member, two or more moving members that are separated from each other in a radial direction perpendicular to the main axis based on the advancing and retreating operation of the chuck operating member, and positions corresponding to the moving members of the chuck body, respectively Intermediate portions of the movable members are pivotally supported, and their first ends are in contact with the outer end portions of the respective moving members so as to rotate around the intermediate portion of the first end portions, and are opposite to the first end portions. Two or more clampers each having a chuck claw at the second end on the side, and between the front end of the chuck actuating member and the opposing surface of each moving member, and in the propulsion direction of the chuck actuating member Advances in response to the pressing force, An intermediate member configured to convert the force into a pressing force of the moving motion of the moving member in the radial direction and transmit the force, and to be movable independently from the axis of the main shaft in the radial direction. Effectively achieved by the chucking device of the machine tool.

  According to a preferred aspect of the present invention, the moving members are slidable in a radial direction perpendicular to the main axis on the chuck body, and are urged toward each other in the approaching direction. It is preferable that the contact end surface with the intermediate member is formed on an inclined surface where the facing distance between the moving members gradually decreases in the propelling direction of the chuck actuating member. Further, it is desirable that a contact surface of the first end portion of the clamper with the moving member is formed as a curved surface protruding in the facing direction.

  The intermediate member is preferably a sphere, or the intermediate member is formed of a truncated cone or truncated pyramid, and a center hole is formed from the center of the bottom surface to the center of the top surface, and the chuck A support pin extending along the main axis from the distal end of the actuating member may be loosely inserted into the center hole, and the intermediate member may be supported by the support pin so as to be freely movable in the radial direction.

  Furthermore, the present invention includes an inner / outer diameter machining method characterized in that the inner / outer diameter machining of an eccentric workpiece having a machining center biased is performed using the chucking device described above. That is, the inner and outer diameter machining methods include positioning and fixing the machining center of the workpiece at a machining position on the main axis in the machine tool, propelling the chuck operating member of the chucking device having the above configuration, and gripping the workpiece. And machining the inner and / or outer diameter of the workpiece.

Effects of the invention

  In the present invention, when the chuck operating member is propelled, the intermediate member is also pushed forward by the chuck operating member. Due to the pressing force at this time, the opposite end surface of each moving member that contacts a part of the peripheral surface of the intermediate member is in the radial direction perpendicular to the main axis with respect to the moving direction of the intermediate member, that is, each moving member is in the separating direction. It is pushed out. When each moving member moves in the separating direction, each clamper whose intermediate portion is pivotally supported by the chuck body rotates about the intermediate portion, and is inserted between chuck claws attached to the second end portion thereof. Is gripped by two or more chuck claws.

  Here, if the work center of the workpiece is the center of the spindle, the gripping center between the chuck claws is the same, and the amount of movement of the pair of moving members moved by the intermediate member is not different. The reaction force of the moving member is applied equally to the intermediate member. As a result, the moving direction of the intermediate member maintains a linear movement in the same manner as the moving direction of the chuck actuating member. Therefore, when the workpiece processing center coincides with the spindle center, the intermediate member can move freely in the radial direction with respect to the axis of the spindle, but the position of the intermediate member at the completion of gripping the workpiece is The intermediate member stops on the main axis, and the intermediate member securely holds the workpiece at an accurate position without moving in the radial direction orthogonal to the main axis. This aspect is most suitable for outer diameter machining of a workpiece, for example.

  On the other hand, even when there is a deviation (eccentricity) between the machining center of the workpiece and the center of the spindle, the intermediate member moves on the spindle along with the propulsion of the chuck operating member. By the movement, the inclined surface of the moving member receives a radial force perpendicular to the main axis from the intermediate member, and the moving body moves in the radial direction with respect to the main axis. The force in the moving direction due to the movement of the moving body acts on the first end portions of the two or more clampers to rotate each clamper equally in the gripping direction around each intermediate portion. In the middle of this rotation, a chuck claw that grips the gripping surface at the position farthest from the processing center first comes into contact with the gripping surface. Even after one of the chuck claws abuts on the gripping surface that is farthest from the processing center, the turning force by the moving member acts on the chuck claw, but the processing center of the workpiece is fixed and fixed in advance. Therefore, the moving member stops and becomes immobile, and further rotation of the clamper is prevented.

  Even in this state, the other chuck claws that grip the gripping surface that is closer to the gripping surface that is farthest from the processing center still need to move in the gripping direction. In order to move other chuck claws, the chuck actuating member continues to move in the propulsion direction. If the movement of the chuck actuating member is continued, the intermediate member attempts to move the two or more moving members in a separating direction. However, the clamper having the chuck pawl that is in contact with the workpiece is in an immobile state despite the movement of the chuck operating member. At this time, the reaction force of the moving member that is in contact with the first end portion of the clamper that is stationary is acting on the intermediate member.

  In the present invention, since the intermediate member can independently and independently move in the radial direction orthogonal to the main axis, the clamper having the chuck claw in contact with the workpiece is still in a stationary state. Then, the other moving member is moved further away through the intermediate member. That is, the intermediate member is moved in the propulsion direction along the main axis while keeping the contact position between the intermediate member and the moving member that is in contact with the clamper having the chuck claw in contact with the workpiece, The movement in the radial direction perpendicular to the main axis is performed simultaneously, and in response to the oblique movement of the intermediate member with respect to the propulsion direction at that time, the other moving member is moved away from the previous moving member in the stationary state. Move. Due to the movement of the moving member, the clamper in contact with the moving member continues to rotate, and finally the chuck claw of the clamper comes into contact with the corresponding gripping surface of the workpiece.

  These operations are sequentially performed on each eccentric gripping surface, and all the gripping surfaces are securely gripped by the corresponding chuck claws with the gripping center being decentered from the spindle center (processing center). Complete gripping. That is, even an eccentric workpiece can be automatically and accurately gripped simply by propelling the chuck operating member. This aspect is suitable for inner diameter machining in which the machining center is eccentric with respect to the gripping center of the workpiece.

  When the urging force in the direction in which the moving members approach each other is applied, the chuck claw is normally maintained with the maximum workpiece gripping interval, and various types of outer diameters and outer peripheral shapes are different. Even a workpiece has the automatic alignment function as described above, so that it can be easily carried between the chuck claws. In addition, by configuring the moving member as a sliding body that slides on the chuck body, the moving body can be stably moved. Furthermore, since the contact end surface of each moving member with the intermediate member is formed as the inclined surface as described above, as the intermediate member is propelled, the distance between the moving members is surely gradually increased at the same rate. Can do. Further, when the contact surface of the first end portion of the clamper with the moving member is formed as a curved surface protruding outward, the contact portion of the moving member by the rotation of the clamper whose intermediate portion is pivotally supported by the chuck body It changes following the rotation to make the clamper rotate smoothly.

  As a preferable aspect of the intermediate member, a spherical sphere, or a truncated cone or truncated pyramid having a truncated cone shape or a truncated pyramid shape that is loosely supported by a support pin extending in the center line direction is adopted. As the chuck actuating member is moved in the workpiece gripping direction, that is, the propulsion direction, the intermediate member is also pushed out in the same propulsion direction as the chuck actuating member. At this time, the inclined surfaces of the plurality of moving members are in contact with a part of the peripheral surface of the intermediate member, and the distance between the inclined surfaces of the moving members gradually increases due to the propulsion operation of the intermediate member. The moving member is spaced apart in the radial direction about the main axis, and the chuck claw of the first rod-like crumbler contacts the workpiece. The spherical body, the truncated cone, or the truncated pyramid is configured to be freely movable in the radial direction perpendicular to the main axis, so that two or more chuck claws simultaneously work on the workpiece gripping surface (main axis center and machining). In the case of a workpiece with the same center.) Grasp or automatically grip the eccentric gripping surface of the workpiece in order of increasing eccentric distance.

  When using the chucking device of the present invention having the above-described configuration, for example, when machining the inner diameter of a workpiece using a lathe, first, the workpiece is loaded into the machining position, and the machining center of the workpiece is positioned at the machining center of the lathe. Temporarily fix the workpiece. For this temporary fixation, an external device such as a collet may be used. In the present invention, as described above, even when the machining center (main spindle center) coincides with the gripping center or when the machining center and the gripping center are deviated from each other, the chuck operating member is automatically operated. Thus, the work center of the work is accurately matched with the center of the spindle, and the work is gripped reliably and automatically. Therefore, both the outer diameter machining and the inner diameter machining can be performed quickly and accurately by the same operation.

Hereinafter, the best embodiment of the present invention will be specifically described with reference to the drawings.
FIG. 1 shows a part of an NC lathe of a machine tool showing the arrangement of a chucking device and a main shaft, which is a typical embodiment of the present invention, applied to the inner diameter machining of a workpiece made of a rectangular plate. 2 is a longitudinal sectional view showing the chucking device, and FIG. 3 is a sectional view taken along the line III-III in FIG. 4 is a cross-sectional view taken along the line IV-IV in FIG. FIG. 5 is a cross-sectional view taken along the line V-V in FIG. As is apparent from these drawings, in this embodiment, the workpiece is gripped by a pair of chuck claws. However, the workpiece is not necessarily limited to a pair. For example, the workpiece is gripped by three or four chuck claws. You may do it. Thus, the present invention is not limited to the embodiment shown in the drawings, and various modifications can be made without departing from the scope of the claims.

  The chucking device 1 according to the present embodiment is fixed to a tip end portion of a main shaft 100 in an NC lathe via a chuck body 10. The chuck body 10 is formed of a hollow cylindrical body having a canopy portion 11 and a bottom portion 12. The canopy 11 is formed with two rectangular through holes 13 into which a pair of clampers 20 are inserted. Each rectangular through hole 13 is supported by a pin 14 so that an intermediate portion of the clamper 20 can freely rotate in a direction perpendicular to the main axis. A grease nipple 15 is provided at the center of the canopy 11.

  A small-diameter hole portion 12a and a large-diameter hole portion 12b communicating with the hollow space are formed in the center portion of the bottom portion 12 of the chuck body 10 via a step surface 12c. A bush 16 having the same inner diameter as the inner diameter of the large-diameter hole 12b that protrudes integrally to the outside is provided on the outer peripheral edge of the large-diameter hole 12b. The bush 16 is fitted into the cylindrical main shaft 100, while the chuck body 10 is fastened and fixed to the front end surface of the main shaft 100 with six tightening bolts 17 with a phase difference of 60 °. A piston rod 101 is liquid-tightly inserted into the hollow portion of the main shaft 100. A stepped columnar chuck actuating member 30 in which a large-diameter portion 31 and a small-diameter portion 32 are integrally formed via a step surface 33 is fixedly provided at the tip of the piston rod 101. As shown in FIG. 1, a key groove 31a extending in the axial direction is formed on the peripheral surface of the large-diameter portion 31 of the chuck operating member 30, and the key 16a attached to the bush 16 is fitted into the key groove 31a. The chuck operating member 30 is guided in the axial direction on the inner surface of the bush 16, and the chuck operating member 30 is prevented from rotating about the axis. When the piston rod 101 is at the non-operating limit position shown in FIG. 2, a step surface 12c that connects the small diameter hole portion 12a and the large diameter hole portion 12b, and a step that connects the large diameter portion 31 and the small diameter portion 32. An operation space S is formed between the surface 33 and when the piston rod 101 is operated, the stepped surfaces 12c and 33 come into contact with each other to stop further operation of the piston rod 101.

  A steel sphere 40 having a diameter slightly smaller than the diameter of the small-diameter hole 12a formed in the chuck body 10 is supported at the tip of the chuck operating member 30 so as to be freely movable. In this embodiment, when the piston rod 101 is in the non-operating limit position, as shown in FIG. 2, more than half of the spherical body 40 enters the internal space of the chuck body 10 from the small diameter hole 12a. Is in a state. On the other hand, a rectangular movable body guide block 50 is disposed in the central region of the internal space of the chuck body 10. As shown in FIGS. 2, 3, and 5, the moving body guide block 50 includes a pair of first side surfaces 51 that extend between the insides of the pair of rectangular through holes 13 formed in the canopy portion 11 of the chuck body 10. And a pair of second side surfaces 52 extending along the respective rectangular through holes 13, and a third side surface 53 in contact with the bottom portion 12 of the chuck body 10. The moving body guide block 50 is fixed to the canopy 11 with a bolt (see FIG. 5).

  Between the first side surfaces 51 of the movable body guide block 50, as shown in FIG. 5, a movable body guide through hole 55 is formed at the center thereof. Further, the canopy 11 and the third side surface 53 of the moving body guide block 50 have four corresponding screw holes, as shown in FIG. The guide block 50 is integrally fixed to the canopy 11 with a bolt 56. On the other hand, the movable body guide block 50 has a fourth side surface (see FIG. 5) on the front side and the rear side in FIG. 1, and the central portion of the fourth side surface 54 faces the third side surface 53. A chevron-shaped recess 58 parallel to the first side surface 51 with the interval gradually reduced is formed so as to penetrate between the second side surfaces 52. A pair of moving bodies 60 according to the present invention is slidably inserted into the moving body guide through hole 55. Further, a pair of spring insertion holes 57 penetrating between the first side surfaces 51 parallel to the movable body guide through-holes 55 are provided at the second side surface side end portions of the pair of first side surfaces 51 of the movable body guide block 50. A spring spring 22 to be described later that elastically supports the first end portion (lower end portion in FIG. 2) 21 of the clamper 20 is inserted into the spring insertion hole 57 formed.

  The canopy portion 11 is unitized with the clamper 20 attached, and is configured to be separable / assembleable so as to be exchangeable from other portions of the chuck body 10. Reference numerals 11a and 11b in FIG. 5 denote positioning pins and positioning bolts, and pin insertion holes 11c and positioning bolt screw holes are provided at positions partially opposed to the canopy 11 and the close contact end surface of the cylindrical portion to which the canopy 11 is assembled. Is formed.

  As shown in FIGS. 2 and 3, the pair of moving bodies 60 have a shape in which one end of a cylindrical body is formed on an inclined surface 61, and a mountain-shaped space is formed between the inclined surfaces 61. The movable body guide through hole 55 is inserted so as to face each other. The movable body guide block 50 having the above-described configuration is disposed in the internal space of the chuck body 10, and the movable body 60 is slidably inserted into the movable body guide through hole 55 of the movable body guide block 50. Accordingly, as shown in FIG. 2, the spherical body 40 serving as an intermediate member includes a tip end surface of the chuck actuating member 30, a mountain-shaped depression 58 of the moving body guide block 50, and an inclined surface 61 of the moving body 60. It will be arranged so as to be sandwiched between.

  In the present embodiment, a sliding guide groove 62 extending in the longitudinal direction is formed in a part of the peripheral surface of the moving body 60 (upper end surface in FIG. 2), and the movement is made in the sliding guide groove 62. A moving body guide pin 55 a protruding from the corresponding inner surface of the body guiding through hole 55 is fitted, so that the moving body 60 is smoothly slid and guided inside the moving body guiding through hole 55. The sliding guide groove 62 is replenished with grease supplied from a grease nipple 15 disposed at the center of the canopy 11 of the chuck body 10 through a grease passage 11d. Further, a dust-proof cover 19 is attached between the canopy 11 and the clamper 20 to block the rectangular through-hole 13 formed in the canopy 11 and prevent entry of a facet or the like. . The dust cover 19 is preferably elastic and flexible so as not to hinder the rotation operation of the clamper 20, and a rubber material is employed in this embodiment.

  As shown in FIGS. 2 and 3, the pair of clampers 20 includes a rod portion 20a having a rectangular cross section, and a pivoting portion 20b that protrudes at right angles from an intermediate portion of the rod portion 20a. A spring support pin 23 is attached to each first end portion 21 in parallel to the first side surface 51 of the movable body guide block 50, and the two tension springs 22 are attached to both ends of each spring support pin 23. Are attached to both ends. The pivoting portions 20b of the clamper 20 inserted into the two rectangular through holes 13 of the canopy portion 11 are supported by the support pins 14 respectively attached to the rectangular through holes 13 so as to freely rotate (swing). The

  On the other hand, at the second end 24 opposite to the first end 21 of each clamper 20, a bolt-shaped gripping member 25, which is a chuck claw, is formed on the second end 24 with the heads 25 a facing each other. Screwed into the screw hole. A nut 25b is attached to the screw end of the head of the bolt-shaped gripping member 25. By operating the nut 25b according to the gripping interval of the workpiece W, the nut 25b is orthogonal to the second end 24 of the clamper 20. The amount of protrusion of the head 25a that protrudes is adjusted. In the present embodiment, of the pair of clampers 20, the second end portion 24 of one of the clampers 20 is formed in a T shape in the left and right side view of FIG. A gripping member 25 is attached. This is for the purpose of strengthening the gripping of the eccentric work 1 because the clamper 20 is a pair in the present embodiment. For example, when three or more clampers 20 are arranged, the second end 24 is provided. There is no need to form a T-shape.

  When the chucking device 1 according to the present embodiment having the above configuration is mounted on an NC lathe, the operation procedure until the eccentric workpiece W having a rectangular plate shape is gripped is simplified for the chucking device 10. This will be specifically described with reference to FIGS. Note that the chucking device according to the present invention can also be applied to a workpiece rotating machine tool other than an NC lathe. In these drawings, members corresponding to the respective members of the chucking device 1 according to the embodiment are given the same reference numerals. However, the tension spring is replaced with a compression spring for convenience of illustration. Therefore, the compression spring is also given the same reference numeral 22 as that of the tension spring.

  In the present embodiment, first, the chucking device 1 according to the present invention is mounted on a spindle 100 (not shown) of an NC lathe. At this time, as shown in FIG. 6, a centering member C made of a collet, a knocking rod or the like of an external device for centering is inserted into a centering hole Wa previously opened at the processing center position of the rectangular plate-shaped eccentric work W. Insert tightly and center. Here, as shown in FIG. 6, the eccentric workpiece W has a rectangular plate shape, the dimension between the processing center O and one long side portion is L1, and between the processing center O and another long portion. The dimension is L2, and L1> L2. On the other hand, the dimension between the machining center O of the eccentric workpiece W and the distance between the opposing short sides is the same dimension L3.

  After the centering by the external device for centering is completed, the eccentric work W is moved between a pair of bolt-shaped gripping members 25 attached to the second end portion 24 of the clamper 20, as shown in FIG. Let it fix. At this time, the machining center of the eccentric workpiece W is on the main axis, and according to the chucking device 1 of the present invention, the eccentric workpiece W can be chucked in this state. Processing can be started immediately without performing centering, automatic centering, etc.

  Here, for example, a chucking member 30 completes centering by operating a propulsive force generator (not shown) such as a hydraulic cylinder and extending the piston rod 101 along the main axis that is inserted into the main axis 100. It pushes toward the eccentric work W. As the chuck actuating member 30 is propelled, the sphere 40 supported on the end surface of the small diameter portion of the chuck actuating member 30 also advances in the propelling direction. Due to the forward movement of the spherical body 40, a part of the spherical surface of the spherical body 40 comes into contact with each inclined surface 61 of the pair of moving bodies 60, and the pressing force along the main axis line by the spherical body 40 causes the inclined surface 61 of the moving body 60. And the pressing force is converted into a radial pressing force perpendicular to the main axis with respect to the moving body 60, and the pair of moving bodies 60 are moved in a direction away from each other.

  When the movable body 60 moves, the pair of clampers 20 rotate in a direction in which the bolt-shaped gripping members 25 attached to the second end portions 22 approach each other. At the time of this rotation, first, the head 25a of the bolt-shaped gripping member 25 attached to the second end 24 of one rod-shaped clamper 20 has a larger eccentric dimension as shown in FIG. Abuts on the gripping side surface of the eccentric workpiece W. After the head portion 25a of one bolt-shaped gripping member 25 is brought into contact with the side surface of the eccentric work W having the larger eccentric dimension in this way, the eccentric work W is fixed at the centering position and placed in an immobile state. Therefore, the moving body 60 that presses the first end portion 21 of the one clamper 20 that is in contact with the gripping side surface of the eccentric workpiece W cannot move any further and stops in place.

  At this time, the other moving body 60 still has a gap between the gripping side surface of the eccentric workpiece W on the side where the eccentric dimension is small and the head portion 25a attached to the second end 24 of the other clamper 20. Since it is open, the movement according to the advance of the sphere 40 continues. During this time, as shown in FIG. 10, the other clamper 20 is continuously rotated from the position indicated by the phantom line to the position indicated by the solid line toward the eccentric workpiece W by the moving body 60, and finally the head of the other clamper 20 As shown by the solid line in FIG. 10, the workpiece 25a is strongly pressed against the gripping side surface of the eccentric workpiece W on the smaller eccentric dimension side, without changing the processing center (center of the spindle) of the eccentric workpiece W. W is gripped strongly by the chucking device 1. Here, since the spherical body 40 which is an intermediate member in the present invention can freely move in the radial direction, the spherical body 40 is advanced by receiving a propulsive force on the main axis by the chuck operating member 30, and at the same time, the movement It moves against the elastic force of the compression spring 22 by a force in a direction perpendicular to the main axis that also acts on the inclined surface 61 of the body 60. That is, the movement of the sphere takes a diagonally forward movement away from the main axis from the position of the phantom line shown in FIG. 10 to the position of the solid line. This is realized for the first time because the spherical body 40, which is an intermediate member in the present invention, can move in both directions of a straight movement on the main axis and a floating movement in a direction perpendicular to the main axis.

  As described above, according to the chucking device 1 according to the present embodiment, when the inner diameter machining of the eccentric workpiece W is to be performed, the machining center position of the eccentric machining is centered on the main axis in advance, and the propulsive force is simply set. By simply operating the generator and propelling the chuck actuating member 30 along the main axis, the gripping center of the eccentric workpiece is matched with the processing center (main shaft center) to strongly grip the eccentric workpiece W. Is possible. This applies not only to the eccentric workpiece but also to a normal workpiece whose machining center and gripping center coincide with each other. In this case, the intermediate member moves in the radial direction perpendicular to the main shaft 100. Even if it is possible, since the force received by the pair of moving bodies 60 is uniform, it does not move in the radial direction, and the gripping center and the spindle center inevitably coincide with each other. Therefore, the chucking device according to the present invention can be used as it is when machining the outer diameter of the eccentric workpiece in which the machining center at the time of machining the inner diameter is deviated from the center of the spindle.

  After the eccentric work W has been gripped, as shown in FIG. 11, after removing the centering member C inserted in the centering hole in the center of processing of the eccentric work W in a close-fitting state, In this state, the cutting tool (not shown) is inserted into the centering hole to start the inner diameter machining. In the present embodiment, the grip end surface position of the eccentric work W before the centering member C is extracted is measured using a measuring instrument, and the grip end surface position of the eccentric work W when the centering member C is extracted is determined. When measured again, it was confirmed that there was no change in the positions of both end faces.

  Next, the gripping force of the eccentric workpiece W by the chucking device 1 according to the embodiment when the moving body is locked, that is, when the gripping is completed, is concretely described with reference to FIGS. Explained. 12 and 13 further schematically show the chucking device 1 in the above embodiment. However, these drawings show the gripping state of the eccentric workpiece W during outer diameter processing. Even if it is a non-eccentric workpiece or a deformed workpiece by the same operation by the chucking device 1 according to the above embodiment, the machining center can be automatically matched with the spindle center, Since the workpiece can be gripped accurately and reliably at the same time, it is possible to perform various inner diameter processing and / or outer diameter processing of the workpiece.

As shown in FIG. 12, when the thrust force N is applied to the sphere 40 by the thrust generator, the sphere pressing force F perpendicular to the inclined surface 61 of the moving body 60 works, and the pair of moving bodies 60 are The shaft pressing force XF is applied to slide in the moving body guide through hole 55 of the moving body guide block 50 in the left-right separated direction in FIG. At this time, a Y-axis pressing force YF acts on the sliding surface, and a frictional force μ1 × YF having a friction coefficient μ1 acts. In the figure, the symbol θ indicates the inclination angle of the inclined surface of the moving body 60.
The spherical body pressing force F with respect to the inclined surface 61 of the moving body 60 by the spherical body 40 is represented by N cos θ (0 ° <θ <90 °). Further, the X-axis pressing force XF is expressed by F · sin θ, and the Y-axis pressing force YF is expressed by F · cos θ.

Further, in the chucking device 1 according to the present invention, as shown in FIG. 13, the clamper 20 is a link type, so that the force that the moving body 60 pushes the clamper 20 is the gripping force M by the bolt-shaped gripping member 25. It becomes.
Now, when the friction coefficient of the link portion is μ2, the gripping force M with respect to the workpiece W works from the left and right directions, and the reaction forces YF · μ1 and XF · μ2 due to friction in the Y-axis direction and the X-axis direction are Considering that it works
Formula: M = (XF-.mu.1.YF-.mu.2.XF) .times.2 = 2N cos .theta. (Sin .theta .-. Mu.1.cos .theta .-. Mu.2.multidot.sin .theta.). Here, 0 ° <θ <90 °.

  14A and 14B show a modification of the intermediate member in the present invention. That is, according to this modification, instead of the sphere 40, intermediate members 41 and 42 having a truncated cone shape or a polygonal truncated cone shape are employed as the intermediate member. However, these intermediate members 41 and 42 have pin holes 41a and 42a each having a bottom portion from the center of the lower base toward the center of the upper base. On the other hand, the chuck actuating member 30 has a pin 34 erected along the axis from the center of the upper surface of the small diameter portion 32. Although the diameter d1 of the pin holes 41a and 42a varies depending on the radial travel distance of the intermediate members 41 and 42 having a truncated cone shape or a polygonal truncated pyramid shape, the clearance distance is secured more than the diameter d2 of the pin 34. Set as large as possible.

  Next, a procedure for gripping the eccentric work W by the chucking device according to the present invention when the intermediate members 41 and 42 according to the modified example are employed will be specifically described with reference to FIG. FIG. 15 schematically shows the front chucking device.

  The machining center at the eccentric position of the eccentric workpiece W is positioned on the main axis by a centering external device (not shown) and fixed in advance. In this state, the eccentric work is moved to the gripping space of the chucking device 1 to fix the position. Next, a thrust generating device such as a hydraulic cylinder (not shown) is operated to propel the chuck operating member 30 indicated by a solid line in FIG. 15 forward. During the propulsion, a part of the peripheral surface of the intermediate member 41, 42 in which the pin 34 protruding from the tip surface of the chuck actuating member 30 is loosely inserted into the pin hole 41a, 42a is inclined surfaces 61 of the left and right moving members 60. Since the diameters of the intermediate members 41 and 42 gradually increase as the propulsion position changes, the facing distance between the pair of left and right moving members 60 gradually opens, and the pair of left and right moving members 60 are moved in the separating direction.

  By the movement of the moving member 60 in the separating direction, the moving direction end of the moving member 60 pushes the first end 21 of the clamper 20, and the pair of left and right clampers 20 are moved in the direction in which the second ends 24 approach each other. Rotate. In the middle of this rotation, the bolt-shaped gripping member 25 attached to the second end 24 of the clamper 20 on the left side of the drawing with a large deviation from the processing center is shown in FIG. It contacts the side surface (grip surface) on the side with a large deviation. At this time, as shown by the solid line b in FIG. 10, the bolt-shaped gripping member 25 of the clamper 20 on the right side of the drawing is spaced apart from the side surface (grip surface) on the side where the offset of the eccentric work W is small. Is open.

  Until this time, since the load from the outside is not applied to the second end portions 24 of the left and right clampers 20, the forces are balanced and the left and right moving bodies 60 move left and right with the same movement. However, as described above, when the bolt-shaped gripping member 25 of the left clamper 20 comes into contact with the side surface of the eccentric workpiece W, the clamper 20 is further prevented from rotating, and the moving member 60 also stops moving. On the other hand, since the clamper 20 on the right side of the drawing still has a gap between the bolt-shaped gripping member 25 and the gripping side surface, the clamper 20 continues to rotate as the moving member 60 moves.

  At this time, there is a required gap between the inner peripheral surface of the pin holes 41a and 42a of the intermediate members 41 and 42 and the outer peripheral surface of the pin 34 of the chuck operating member 30, and the intermediate members 41 and 42 are in the radial direction. Therefore, the intermediate members 41 and 42 continue to move in the propulsion direction while receiving the reaction force of the left moving member 60 that has stopped moving while moving in the propulsion direction. The direction also moves to the right, that is, moves diagonally forward in the propulsion direction. In response to the pressing force due to the movement of the moving member 60, the right clamper 20 continues to rotate, and finally reaches the position indicated by the solid line c in FIG. 10, and the bolt-shaped gripping member 25 of the clamper 20 is biased. The abutting side of the core work W with the smaller eccentricity is brought into contact with the gripper side, and the further rotation of the left and right clampers 20 is stopped. Here, the gripping of the eccentric workpiece by the chucking device is completed, and at this time, the machining center of the eccentric workpiece W is on the main axis. When this gripping is completed, as shown in FIG. 11, after the centering member C inserted and fixed in the centering hole formed in advance in the center of machining of the eccentric workpiece is removed from the centering hole, it is not shown. Insert a bite and process the inside diameter in the usual way.

  FIG. 16 shows a modification of the moving member in the present invention. According to this modification, the moving member 60 according to the above embodiment is configured such that one end of the cylindrical body is an inclined surface and the other end is a circular end surface. While being an inclined surface, the elastic contact end surface of the moving member 60 with the first end portion 21 of the clamper 20 is formed in a curved shape protruding toward the elastic contact surface of the first end portion. If formed in such a curved shape, even if the contact position of the elastic contact end surface with respect to the moving body 60 that moves linearly by the rotation of the clamper 20 moves when the clamper 20 rotates, the contact position of the moving body 60 also follows. Thus, the point contact (spherical curved surface) or line contact (arc curved surface) is always maintained, and the clamper 20 is pressed with an equal force. In FIG. 15, the shape of the contact surface of the movable body 60 with the first end of the clamper 20 is described. Conversely, the shape of the contact surface of the first end 21 of the clamper 20 with respect to the movable body 60 is directed toward the movable body 60. The same function can be achieved as a protruding curved shape.

  In the present invention, if the galling between the intermediate member and the moving body 60 can be ignored, a bottomed hollow cylindrical body or a bottomed hollow rectangular cylinder (not shown) can be employed as the intermediate member. . The inner diameter of the hollow portion of the bottomed hollow cylinder or the bottomed hollow rectangular tube may be determined in the same manner as the diameter d1 of the pin holes 41a and 42a, and is a relative value with the diameter d2 of the pin 34. In order to avoid galling the inclined surface 61 of the movable body 60 of the bottomed hollow cylindrical body or the bottomed hollow rectangular cylindrical body, the contact edge of the bottomed hollow cylindrical body or the bottomed hollow rectangular cylindrical body with the inclined surface 61 Chamfering is also a solution. As can be understood from the above description, the present invention is not limited to the above-described embodiments and modifications, and various modifications can be made.

It is a longitudinal cross-sectional view along the main axis of the main-axis part of the NC lathe to which the chucking apparatus which is embodiment of this invention is applied. It is a longitudinal cross-sectional view of the same chucking apparatus. FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 2. It is arrow sectional drawing along the VV line of FIG. It is a shape figure explaining the shape of the eccentric workpiece | work in this embodiment. It is sectional drawing which shows the state at the time of the centering by the centering member of the eccentric work. It is a schematic diagram which shows the relationship between each member at the time of starting of an intermediate member. It is a schematic diagram which shows the one side holding | grip state of the eccentric workpiece | work by the clamper accompanying the movement of the propulsion direction of an intermediate member. It is a schematic diagram explaining the state until it grips an eccentric workpiece | work completely. It is a schematic diagram explaining the state when the centering member after completion | finish of gripping is extracted from the workpiece | work. It is explanatory drawing which shows the relationship of the pressing force with respect to the moving member by the intermediate member at the time of locking of a moving member. It is a schematic diagram for demonstrating the holding | grip force of the workpiece | work by a clamper. It is a perspective view which shows typically the modification of the intermediate member in this invention. It is a schematic diagram for demonstrating the holding | grip procedure when the intermediate member which concerns on the said modification is used. It is a partial schematic diagram which shows the modification of the moving member in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chucking apparatus 10 Chucking main body 11 Canopy part 11a Positioning pin 11b Positioning bolt 11c Positioning hole 11d Grease passage 12 Bottom part 12a Small diameter hole part 12b Large diameter hole part 12c Step surface 13 Rectangular through hole 14 Pin 15 Grease nipple 16 Bush 16a Key 17 Tightening bolt 19 Dust-proof cover 20 Clamper 20a Rod part 20b Pivoting part 21 First end 22 Tension spring (compression spring)
23 Spring Support Pin 24 Second End 25 Bolt-shaped Holding Member 25a Head 25b Nut 30 Chuck Actuating Member 31 Large Diameter 31a Keyway 32 Small Diameter 33 Stepped Surface 40 Sphere (Intermediate Member)
41 Intermediate member (bottomed hollow truncated cone shape)
41a Intermediate member pin hole (bottom truncated cone shape)
42 Intermediate member (bottomed polygonal frustum shape)
42a Intermediate member pin hole (bottom polygonal frustum shape)
DESCRIPTION OF SYMBOLS 50 Mobile body guide block 51 1st side surface 52 2nd side surface 53 3rd side surface 55 Mobile body guide through-hole 55a Mobile body guide pin 56 Bolt 57 Spring insertion hole 58 Angle-shaped hollow 60 Mobile body (sliding body)
61 Inclined surface 62 Sliding guide groove 100 Main shaft 101 Piston rod S Working space C Centering member W Eccentric work Wa Centering hole

Claims (6)

A chuck body fixed to the front of the spindle,
A chuck actuating member that is inserted into a through-hole formed in the center of the chuck body and can be advanced and retracted on the axis of the main shaft by a propulsive force generator;
Two or more moving members that are separated from each other in a radial direction perpendicular to the main axis based on the advancing and retreating operation of the chuck actuating member;
Each intermediate portion is pivotally supported at a position corresponding to each moving member of the chuck body, and the first end of each intermediate member rotates and the first end rotates around the intermediate portion. Two or more clampers having a chuck claw at the second end opposite to each first end,
The chuck actuating member is disposed between the front end of the chuck actuating member and the opposed surfaces of the moving members, and advances by receiving a pushing force in the propulsion direction of the chuck actuating member, and the pushing force is moved in the radial direction of the moving member. An intermediate member that is converted into a pushing force of a moving operation and transmits the intermediate force, and is movable freely in the radial direction from the axis of the main shaft,
A machine tool chucking device comprising: Each moving member is urged in the approaching direction, and comprises a sliding body that can slide on the chuck body in a radial direction perpendicular to the main axis,
The contact end surface of each moving member with the intermediate member is formed as an inclined surface in which the interval between the moving members gradually decreases in the propelling direction of the chuck actuating member.
The chucking device according to claim 1.   The chucking device according to claim 1 or 2, wherein a contact surface of one of the first end portion of the clamper and the moving member is formed as a curved surface protruding in a facing direction.   The chucking device according to claim 1, wherein the intermediate member is a sphere.   The intermediate member is formed of a truncated cone or truncated pyramid, a center hole is formed from the center of the bottom surface toward the center of the top surface, and extends from the tip of the chuck actuating member along the main axis. The chucking device according to any one of claims 1 to 3, wherein a support pin is loosely inserted into the center hole, and the intermediate member is supported by the support pin so as to be freely movable in a radial direction. Positioning and fixing the machining center of the workpiece at the machining position on the main axis of the machine tool;
Holding the workpiece by propelling the chuck actuating member of the chucking device according to any one of claims 1 to 5, and
Machining the inner and / or outer diameter of the workpiece,
An inner / outer diameter machining method in a machine tool comprising:

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