JP4027394B2 - Chuck mechanism, claw material, and lathe - Google Patents

Description

  The present invention relates to a claw material for gripping a workpiece, a chuck mechanism for fixing a gripped workpiece to a machine tool, and a lathe having the chuck mechanism.

When machining a workpiece (work) using a machine tool such as a lathe, the workpiece is fixed on a stage rotatably provided on the spindle and rotated at a high speed together with the spindle. . For example, when machining the outer peripheral surface of a cylindrical workpiece, the workpiece is fixed to the stage by grasping its inner wall surface. At this time, in order to machine the workpiece with high accuracy, it is necessary to perform centering with high accuracy and to hold the workpiece with sufficient strength so that the workpiece does not shake during machining. Further, when the shape and dimensions of the workpiece are different, a mechanism for fixing the workpiece to the stage, for example, a chuck device must be exchanged according to the dimension of the workpiece. For example, Patent Document 1 discloses a chuck body that fits inside a tire wheel and a tire as a chuck device for reducing the labor of such replacement and gripping workpieces having different dimensions with sufficient strength. A tire wheel machining chuck including a clamping claw for clamping an inner surface of a rim portion of a wheel is disclosed. In this tire wheel machining chuck, the clamp pawl is attached to the tip of a lever provided so as to be slidable in the radial direction of the chuck in a replaceable manner with a bolt. Therefore, tire wheels with different inner diameters can be gripped by the same chuck device by adjusting the position of the lever or replacing the clamp pawl according to the tire wheel.
JP 2002-144116 A

  If the workpiece is not fixed to the stage with sufficient strength, not only can the workpiece be machined with high precision, but the workpiece is not stably held during high-speed rotation. There is a possibility that a phenomenon of large vibration, so-called chattering, may occur, or the workpiece may come off the stage without resisting the centrifugal force due to high-speed rotation. Therefore, in order to clamp the workpiece with sufficient strength, a so-called clamping claw in a gripping mechanism such as a chuck device is generally manufactured according to the shape of the target workpiece. In this case, when the workpiece is a member having a small manufacturing tolerance such as the tire wheel, the clamp claws manufactured for the workpiece can be similarly applied to the same type of workpiece. However, for example, if the workpiece is a casting manufactured by casting, its manufacturing tolerance is large, so even if it is the same type of workpiece, the same clamping claw is used to provide sufficient strength. In some cases, it could not be gripped. In other words, if the manufacturing tolerance is large and the dimensions of each workpiece are slightly different, it may be necessary to process the clamp claws according to each workpiece. Furthermore, when the workpiece is cylindrical, the workpiece is gripped using a plurality of circumferentially arranged clamp claws, but each clamp is adjusted according to the subtle differences in the dimensions of each workpiece. In some cases, the balance of the tightening strength of the nails must be finely adjusted. For this reason, the work of fixing the workpiece to the gripping mechanism is a difficult work with many man-hours, and there is a problem that even a skilled worker needs a lot of time.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a chuck mechanism that can easily fix a workpiece with sufficient strength to a machine tool regardless of manufacturing tolerances of the workpiece, and a claw material that can be used for such a chuck mechanism. Is to provide.

  According to the first aspect of the present invention, there is provided a chuck mechanism for gripping a workpiece, a stage, a fixed claw having a base fixed to the stage and a fixed claw extending from the base, A movable claw provided between the workpiece and the fixed claw for gripping the workpiece, a support portion that contacts the fixed claw portion, and a first claw that contacts the first portion of the workpiece And a second claw that comes into contact with a second part different from the first part of the workpiece, and the support part exists between the first claw and the second claw in the extending direction of the fixed claw part. There is provided a chuck mechanism including a movable claw positioned so as to be capable of tilting to the base side with the movable claw being the center.

  According to the first aspect of the present invention, when the workpiece is fixed to the chuck mechanism, the movable claw can tilt to the base side (stage side) of the fixed claw with the support portion as the center. Therefore, for example, even when the inner surface of a cylindrical workpiece is gripped and the inner surface of the workpiece is uneven, the movable claw rotates about the support portion, and the movable claw The tips of the first and second claws can contact the inner surface of the workpiece. This is particularly advantageous when there are irregularities extending in the axial direction on the inner surface of a cylindrical or annular workpiece. In addition, as a result of the movable claw tilting about the support portion, the tip of the first claw and the second claw is tilted slightly toward the base with respect to the plane parallel to the base of the fixed claw. When abutting, the workpiece is fixed in a state of being pressed toward the base side of the fixing claw. Therefore, even if the workpiece is rotated at high speed, there is no possibility that the workpiece will jump out to the side opposite to the base portion of the fixed claw. Here, when the workpiece is gripped, either the inner or outer surface can be gripped.

  In the chuck mechanism of the present invention, a buffer member may be further provided between the movable claw and the base of the fixed claw, and a gap may be formed between the movable claw and the base of the fixed claw. In this case, the range in which the movable claw can be tilted can be adjusted by the size of the gap formed between the movable claw and the base of the fixed claw. That is, the gap between the movable claw and the base of the fixed claw can be adjusted so that the movable claw can be tilted to the base side until both the first claw and the second claw of the movable claw contact the workpiece. .

  In the chuck mechanism of the present invention, the first claw is located closer to the base in the extending direction of the fixed claw than the second claw, and the distance between the support and the tip of the first claw is You may be longer than the distance between the said support part and the front-end | tip of a 2nd nail | claw. At this time, when the tips of the first and second claws turn toward the base side of the fixed claw, the tips of the second claws can be pressed against the inner surface of the workpiece with a strong force. Here, since the support portion, the first claw, and the second claw serve as a fulcrum, a force point, and an action point, respectively, the length of the support portion and the first claw is determined by the lever principle. The longer the length is, the more the tip of the second claw is pressed against the workpiece with a strong force.

  In the chuck mechanism of the present invention, the support portion may be located on a side closer to the second claw in the extending direction of the fixed claw portion. With respect to the extending direction of the fixed claw portion, the angle between the extending direction of the fixed claw portion and the direction from the support portion toward the first claw becomes smaller as the support portion is positioned closer to the second claw. Therefore, it is possible to increase the force component that tries to rotate the movable claw toward the base side of the fixed claw with respect to the force acting on the tip of the first claw. Furthermore, when the support portion is located on the side close to the second claw in the extending direction of the fixed claw portion, the support portion is easily slid on the fixed claw portion to the side opposite to the base portion of the fixed claw. At that time, the first claw and the second claw can be inclined to the base side of the fixed claw at a larger angle. In such a case, the force for pressing the workpiece against the base side of the fixed claw is increased.

  In the chuck mechanism of the present invention, a groove may be formed at the tip of one of the first claw and the second claw. Further, the groove may extend in a direction in which the fixed claw portion extends. In these cases, the tip of the first claw and / or the second claw is not in contact with the workpiece in the grooved region. The mechanism can be gripped appropriately avoiding unevenness. In particular, when the groove extends in the extending direction of the fixed claw portion, for example, in a cylindrical workpiece, it is effective when there is an unevenness extending in the axial direction. In the chuck mechanism of the present invention, the movable claw may be a plate-like member having a bent portion, and the support portion may be a ridge line of the bent portion. In this case, the movable claw can tilt about the ridgeline.

  In the chuck mechanism of the present invention, the movable claw may be attached to the base portion of the fixed claw so as to be movable in the surface direction of the base portion, and the movable claw is attached to the base portion of the fixed claw. On the other hand, it may be rotatably attached in the plane of the base. In such a case, the movable claw can be finely moved in any direction in the surface direction of the base of the fixed claw according to the shape of the workpiece to be gripped, or in a plane parallel to the base of the fixed claw. Therefore, even a workpiece with a large manufacturing tolerance can be gripped appropriately. For example, when gripping the inner surface of a cylindrical or annular workpiece, even if the inner surface has irregularities along the circumferential direction, the movable claw can finely move according to the irregularities. The inner surface of the can be properly gripped.

  In the chuck mechanism of the present invention, when the fixed claw is urged against the workpiece, the movable claw may rotate about the ridge line toward the base side of the fixed claw. In this case, when the fixed claw is urged against the workpiece, the movable claw rotates toward the base side of the fixed claw, so that the movable claw presses the workpiece toward the base side of the fixed claw. And you can fix the workpiece. Therefore, for example, even when a cylindrical workpiece is rotated at a high speed with the central axis as a rotation axis, there is no possibility that the workpiece will jump out to the side opposite to the base.

  In the chuck mechanism of the present invention, the fixed claw may be constituted by a plurality of fixed claws, and a plurality of movable claws may be attached to each fixed claw. In this case, each of the plurality of movable claws attached to the plurality of fixed claws can finely move. Therefore, since the degree of freedom of movement of the chuck mechanism in accordance with the shape of the workpiece is increased, even a workpiece having a large manufacturing tolerance can be easily gripped.

  In the chuck mechanism of the present invention, each of the plurality of fixed claws may have an arch shape and be arranged in a circumferential shape. In this case, for example, a cylindrical or annular workpiece can be easily and sufficiently gripped.

  According to the second aspect of the present invention, a machine tool including the chuck mechanism of the present invention is provided. If the movable claw is in contact with the workpiece while tilting toward the base of the fixed claw, for example, even if the workpiece is rotated at a high speed to process the workpiece, the workpiece will move to the stage side. Since it receives the force to be pressed, there is no risk of the workpiece popping out on the opposite side of the stage. Moreover, the machine tool provided with the chuck mechanism of the present invention may be a kind selected from the group consisting of a lathe, a milling machine, and a machining center. In this case, either a machine tool that processes while moving the workpiece at a high speed while the workpiece is fixed to the chuck mechanism, or a machine tool that processes a workpiece by moving a cutting part such as a blade at high speed. Even in this case, the chuck mechanism of the present invention can be used. In any case, since the workpiece receives a force that is pressed to the stage side of the chuck mechanism, there is no possibility of the workpiece jumping out to the opposite side of the stage.

  According to the third aspect of the present invention, there is provided a claw material used in a chuck mechanism for gripping a workpiece, which has a base and a fixed claw extending from the base, and the workpiece and the fixed claw. A support claw that contacts the fixed claw, a first claw that contacts the first part of the workpiece, and a second part different from the first part of the workpiece. A movable claw having a second claw in contact with the movable claw, wherein the movable claw is positioned such that the support portion exists between the first claw and the second claw in the extending direction of the fixed claw portion, A nail material that can be tilted to the base side around the support portion is provided. Further, the fixed claw and the support portion may be arched, and the workpiece may be a cylindrical or annular workpiece.

  According to the 3rd aspect of this invention, a workpiece can be hold | gripped with sufficient intensity | strength by using this nail | claw material. Further, even when the manufacturing tolerance of the workpiece is large, the workpiece can be easily gripped with sufficient strength without producing a claw material for each workpiece.

  Even a member having a large manufacturing tolerance, such as a workpiece manufactured by casting, can fix the workpiece to the chuck mechanism without manufacturing a claw material for each workpiece.

  Hereinafter, the chuck mechanism of the present invention will be described with reference to the drawings. A lathe 100 shown in FIG. 1 includes a chuck mechanism 1 for gripping a workpiece (workpiece) to be processed, a motor (drive source) 101 for rotationally driving the chuck mechanism 1, and a rotation shaft of the motor 101. In conjunction, a shaft (spindle) 102 that transmits the rotational power generated by the motor 101 to the chuck mechanism 1 and a control unit 103 for controlling the operation of the motor 101 are provided. Based on the command from the control unit 103, the rotation direction and the rotation speed of the motor 103 are adjusted.

  As shown in FIGS. 1 and 2 (a) and 2 (b), the chuck mechanism 1 includes a stage 12 provided rotatably with respect to the shaft 102, a fixed claw 11 provided at the tip of the stage 12, A movable claw 10 is provided on the fixed claw 11 so as to be swingable.

  The stage 12 includes a substantially cylindrical fixed stage 13 and three movable stages 14 provided on the fixed stage. The central axis X of the fixed stage 13 coincides with the direction in which the shaft 102 extends, and the fixed stage 13 is fixed to the shaft 102 so as to be rotatable. That is, the center axis X of the stage 12 coincides with the rotation axes of the shaft 102 and the fixed stage 13. Three movable stages 14 are provided on the end surface 13 a of the fixed stage 13 opposite to the shaft 102 so as to be movable in the radial direction of the fixed stage 13. Each movable stage 14 has a substantially arched shape with a central angle of about 120 °, that is, a shape obtained by dividing a donut-shaped disk having a hollowed center portion into approximately three equal parts. Are provided at substantially equal intervals in a circumferential shape centered on the central axis X. These movable stages 14 are driven in the radial direction of the fixed stage 13 by a drive mechanism (not shown). The end surface 14a opposite to the fixed stage 13 of each movable stage 14 is formed as a flat surface. Bolt holes (not shown) for attaching the fixed claws 11 are provided on the end surface 14 a, and one fixed claw 11 is attached to each movable stage 14.

  Each fixed claw 11 extends in the circumferential direction at a base portion 11a that is a flat plate having a substantially arch shape with a central angle of about 120 °, and a substantially central portion in the radial direction of the base portion 11a, and the base portion 11a. And a claw portion (fixed claw portion) 11b erected perpendicular to the surface. The fixed claw 11 is fixed to the fixed stage 12 using bolts, and is provided to be rotatable integrally with the fixed stage 12 with respect to the shaft 102. Although not shown in FIGS. 1 and 2 (b), the fixed claw 11 includes a hole 11d in which a bolt 40 for fixing the movable claw, which will be described later, engages, and the movable claw and the fixed claw. Four holes 11c are provided for providing a buffer member 41 interposed therebetween.

  As shown in FIG. 3, the movable claw 10 includes a base portion 10g that is a bent plate material with a ridge line (support portion) 10a as a peak, and a first claw 10b that protrudes upward from one end of the base portion 10g in FIG. And the 2nd nail | claw 10c which protrudes toward the same direction as the 1st nail | claw 10b from the other end of the base 10g is provided. The base 10g is curved in an arc shape along the direction of the ridge line 10a, and the tips of the first claw 10b and the second claw 10c are also formed in an arc shape in the same direction. Further, the ridge line 10a is also curved in an arc shape. Moreover, the 1st nail | claw 10b is formed longer than the 2nd nail | claw 10c. That is, the distance L1 between the ridge line 10a and the tip of the first claw 10b is longer than the distance L2 between the ridge line 10a and the second claw 10c. In addition, a plurality of grooves 10d that are arranged at intervals along the circumferential direction and extend in the thickness direction of the first claw 10b are formed at the tip of the first claw 10b. Furthermore, the surface (back surface 10f) on the opposite side to the second claw 10c of the first claw 10b is formed flat. Further, a through hole 10e penetrating from the surface side where the first claw 10b is formed to the back surface 10f side is formed at a substantially central portion of the base portion 10g. A bolt 40 described later is inserted into the through hole 10e (see FIG. 4), but the inner diameter of the through hole 10e is slightly larger than the diameter of the bolt 40.

  Next, the arrangement of the movable claw 10 will be described. As shown in FIG. 2A, four movable claws 10 are attached along the circumferential direction on the outer peripheral side of the claw portion 11 b of each fixed claw 11. Here, as shown in FIG. 4, each movable claw 10 is attached in contact with the base 11 a and the claw 11 b of the fixed claw 11 with the first claw 10 b facing the base 11 a of the fixed claw 11. . That is, the base portion 11 a of the fixed claw 11 is in contact with the back surface 10 f of the movable claw 10, and the claw portion 11 b of the fixed claw 11 is disposed in contact with the ridge line 10 a of the movable claw 10. Four holes 11c for providing a buffer member 41 to be described later are formed at the four corners of the area of the base 11a of the fixed claw 11 in contact with the back surface 10f of the movable claw 10. Further, as will be described later, a predetermined bolt 40 is inserted into the through hole 10e of the movable claw 10 so that the movable claw 10 is tiltably or slidably fixed with respect to the base 11a of the fixed claw 11. .

  Next, the workpiece 20 that is a workpiece attached to the chuck mechanism 1 will be described with reference to FIGS. The illustrated workpiece 20 is an iron / molybdenum alloy cylindrical member manufactured integrally by casting, and includes a cylindrical portion (side portion) 21 and one end side of the cylindrical portion 21 in the central axis O direction (FIG. 5). And a bottom plate portion 22 extending in the axis O direction from the lower side in (b). Further, since the end portion (end surface) 22a of the bottom plate portion 22 does not reach the axis O, a circular through hole is defined by the end portion 22a. Further, the inner surface 20 a of the workpiece 20 is formed as a curved surface that smoothly connects from the inner surface of the cylindrical portion 21 to the end surface 22 a of the bottom plate portion 22. As will be described later, with the workpiece 20 attached to the chuck mechanism 1, the upper surface 21 a, the side surface 21 b, the bottom surface 22 b of the bottom plate portion 22, and the like can be cut.

  Next, a procedure for attaching the fixed claw 11 and the movable claw 10 in the chuck mechanism 1 will be described. First, the three fixed claws 11 are bolted and attached to the movable stage 14 of the chuck mechanism 1 in the arrangement as shown in FIG. Next, as shown in FIG. 4, buffer members 41 such as springs are inserted into the four holes 11 c of each fixing claw 11. A part of the buffer member 41 protrudes from the opening of the hole 11c in a state of being inserted into the hole 11c.

  After the buffer member 41 is inserted into the hole 11c of the fixed claw 11, a predetermined bolt 40 is inserted into the through hole 10e of the movable claw 10, and the movable claw 10 is urged toward the base 11a of the fixed claw 11 by bolting. (See FIG. 4). The bolt 40 does not completely tighten the movable claw 10 with respect to the base 11 a of the fixed claw 11. At this time, the buffer member 41 is inserted into the hole 11 c of the fixed claw 11, and the portion protruding from the hole 11 c of the buffer member 41 abuts on the back surface 10 f of the movable claw 10 to urge the movable claw 11. . In this state, there is a slight gap (gap) G1 between the back surface 10f of the movable claw 10 and the base portion 11a, and the urging force of the movable claw 10 on the fixed claw 11 by the bolt 40 and the buffer member 41. The urging force against the movable claw 10 is balanced.

  Next, a procedure for attaching the workpiece 20 to the chuck mechanism 1 will be described. First, as shown in FIG. 6A, the center axis X of the workpiece 20 and the chuck mechanism 1 is aligned with the inner surface 20c of the workpiece 20 facing the fixed claw 11 and the movable claw 10 of the chuck mechanism 1. Then, the workpiece 20 is fitted to the chuck mechanism 1. At this time, each movable stage is arranged such that the first claw 10b of the movable claw 10 contacts the inner surface 20a of the workpiece 20 and the second claw 10c of the movable claw 10 contacts the end surface 22a of the bottom plate portion 22 of the workpiece 20. The position of 14 is adjusted. At this time, the inner diameter of the inner surface 20 a of the workpiece 20 is slightly larger than the outer diameter of the first claw 10 b of the movable claw 10. The inner diameter of the hole defined in the bottom plate portion 22 of the workpiece 20 is substantially the same as the outer diameter of the circle formed by the second claws 10 c of the twelve movable claws 10 incorporated in the three fixed claws 11. Therefore, the workpiece 20 is temporarily fixed to the chuck mechanism 1 by fitting the workpiece 20 to the chuck mechanism 1.

  Next, each movable stage 14 is pressed radially outward (workpiece 20 side) using a drive mechanism (not shown). Thereby, the work 20 is fixed to the chuck mechanism 1 in a state where the first claw 10b and the second claw 10c of the movable claw 10 are tightly fitted to the inner surface 20a of the work 20 and the end surface 22a of the bottom plate part 22, respectively. The At this time, as shown in FIG. 6B, a rod-shaped stopper 30 is disposed between the end surface 13 a of the fixed stage 13 and the inner surface 20 c of the workpiece 20, and the workpiece 20 is placed on the stage 12 side of the chuck mechanism 1. It is also possible to limit the amount of movement.

  At this time, as shown in FIG. 4, each movable claw 10 is fastened to the fixed claw 11 with only one bolt 40. At this time, the through-hole 10e into which the bolt 40 is inserted of the movable claw 10 is formed to have a diameter slightly larger than the diameter of the bolt 40, so that each movable claw 10 is in the direction in which the bolt 40 extends. Can move in any direction within a vertical plane. For example, the bolt 40 can be slightly rotated about the rotation axis, and the movable stage 14 can be slightly moved in the radial direction and the circumferential direction. Further, since the buffer member 41 is inserted into the hole 11c formed in the base portion 11a of the fixed claw 11, a gap G1 is formed between the base portion 11a and the back surface 10f of the movable claw 10. Therefore, the movable claw 10 can be slightly rotated in the directions of arrows R1 and R2 in FIG. 4 with the ridge line 10a as a rotation axis. Furthermore, the movable claw 10 can be finely moved in the direction in which the claw portion 11b of the fixed claw 11 extends. At this time, the base 11a of the fixed claw 11 and the back surface 10f of the movable claw 10 can be swung so that they are not parallel to each other. Further, since the gap between the ridge line 10a of the movable claw 10 and the claw part 11b of the fixed claw 11 is not fixed, the ridge line 10a of the movable claw 10 is the tip side of the claw part 11b of the fixed claw 11 (left side in FIG. 4). It is possible that the movable claw 10 may rotate in the direction of the arrow R1 while sliding toward the front. Thus, the movable nail | claw 10 has the freedom degree which can be moved finely in various directions. Therefore, even when the manufacturing tolerance of the workpiece 20 is large, the manufacturing tolerance of the workpiece 20 can be absorbed by the movable claw 10 slightly moving in the above-described direction. Further, a groove 10d is formed at the tip of the first claw 10b of the movable claw 10, and the tip of the first claw 10b of the movable claw 10 and the inner surface 20a of the workpiece 20 except for the portion where the groove 10d is formed. Touching. That is, the tip of the first claw 10b of the movable claw 10 and the inner surface 20a of the workpiece 20 are in point contact. Therefore, for example, even if the inner surface 20a of the workpiece 20 has irregularities such as small protrusions and depressions, the groove 10d is formed at the tip of the first claw 10b. It can contact the inner surface 20a of the workpiece 20 while avoiding irregularities.

  Next, the movement of the movable claw 10 when the workpiece 20 is fixed to the chuck mechanism 1 will be described in more detail. In the state in which the workpiece 20 is temporarily fixed to the chuck mechanism 1, as shown in FIG. 7, the tip of the first claw 10b and the tip of the second claw 10c of the movable claw 10 are the inner surface 20a of the workpiece 20 and the workpiece 20 respectively. The ridge line 10 a of the movable claw 10 abuts on the base 11 a of the fixed claw 11. At this time, the first claw 10 b and the second claw 10 c of the movable claw 10 are substantially parallel to the base 11 a of the fixed claw 11. Further, a gap G <b> 1 is formed between the back surface of the movable claw 10 and the base portion 11 a of the fixed claw 11 by the buffer member 41.

  Here, as shown in FIG. 7, the pressing force F <b> 3 by the first claw 10 b of the movable claw 10 acts on the inner surface 20 a of the work 20, and the second claw 10 c of the movable claw 10 acts on the end surface 22 a of the work 20. The pressing force F4 works. The directions of these pressing forces F3 and F4 are both directed toward the outside of the workpiece 20 in the radial direction.

  As shown in FIG. 8, reaction forces F1 and F2 of the pressing forces F3 and F4 act on the tips of the first claw 10b and the second claw 10c of the movable claw 10. The reaction forces F1 and F2 are forces of the same magnitude in the opposite directions to the pressing forces F3 and F4, respectively. Here, FIG. 8 is a diagram schematically showing the force applied to the movable claw 10, and the shapes of the movable claw 10 and the fixed claw 11 are omitted for easy understanding of the drawing. As shown in FIG. 8, the reaction force F1 includes a component F1b from the tip of the first claw 10b toward the support portion 10a and a component F1a perpendicular thereto. Similarly, the reaction force F2 includes a component F2b from the tip of the second claw 10c toward the support portion 10a and a component F2a perpendicular thereto. At this time, the magnitude of the force moment (clockwise moment) for rotating the movable claw 10 in the direction of the arrow R1 around the ridge line 10a is the product of the magnitude of the force F1a and the distance L1. The magnitude of the force moment (counterclockwise moment) for rotating the movable claw 10 in the direction of the arrow R2 is the product of the magnitude of the force F2a and the distance L2. In the present embodiment, since the distance L1 is longer than the distance L2, the clockwise moment is larger than the counterclockwise moment. Therefore, the movable claw 10 rotates in the direction of the arrow R1 with the ridge line 10a as the central axis.

  When the movable claw 10 is slightly rotated in the direction of the arrow R <b> 1 with the ridge line 10 a as the rotation axis, the tip of the second claw 10 c is slightly moved outward in the radial direction of the chuck mechanism 1. In this case, the 2nd nail | claw 10c presses the end surface 22a of the base 22 of the workpiece | work 20 still more strongly. In this way, the chuck mechanism 1 and the workpiece 20 are fitted with sufficient strength.

  Here, the distance L1 between the ridge line of the movable claw and the first claw is longer than the distance L2 between the ridge line of the movable claw and the second claw. When the movable claw 10 rotates in the direction of the arrow R1 with the ridge line 10a as the rotation axis, the larger the value of L1 / L2 by the lever principle, the larger the component of the force that presses the second claw against the work, so the stronger It is advantageous in that the workpiece can be fixed to the chuck mechanism by force. Further, the longer the length of L1, the smaller the angle between the direction in which the claw portion 11b of the fixed claw 11 extends and the direction from the support portion 10a of the movable claw 10 toward the tip of the first claw 10b. However, it is advantageous that the moment of the force for rotating the movable claw 10 to the base 11a side of the fixed claw 11 is increased.

  So far, the case where the ridge line 10a of the movable claw 10 and the claw portion 11b of the fixed claw 11 are in contact at the same position has been described. However, as described above, the gap between the ridge line 10a of the movable claw 10 and the claw portion 11b of the fixed claw 11 is not fixed. Therefore, when the force pressing the movable stage 14 toward the workpiece 20 is sufficiently strong, the ridge line 10a of the movable claw 10 slides toward the tip side (left side in FIG. 7) of the claw portion 11b of the fixed claw 11. However, the movable claw 10 may rotate in the direction of the arrow R1. In any case, when the chuck mechanism 1 and the workpiece 20 are fitted with sufficient strength, the movable claw 10 contacts the workpiece 20 in the state shown in FIG. That is, as a result of the movable claw 10 being slightly rotated in the direction of the arrow 20 with the ridge line 10 a as the central axis, the first claw 10 b and the second claw 10 c of the movable claw 10 are slightly tilted toward the base 11 a of the fixed claw 11. In contact with the workpiece 20 in the state where

  In this way, after the workpiece 20 is fitted to the chuck mechanism 1 with sufficient strength, the workpiece 20 can be rotated at a high speed while being fixed to the chuck mechanism 1, and desired processing can be applied to the workpiece 20. . In the case of the present embodiment, since the workpiece 20 is gripped from the inside, the top surface 21a, the side surface 21b, the bottom surface 22b of the bottom plate portion 22, The end face 22a can be cut.

  Next, the force working between the workpiece 20 and the chuck mechanism 1 in a state where the workpiece 20 is fitted to the chuck mechanism 1 will be described with reference to FIG. The first claw 10b and the second claw 10c of the movable claw 10 are in contact with the workpiece 20 while being slightly inclined toward the base 11a of the fixed claw 11. At this time, the force that the first claw 10b of the movable claw 10 presses the inner surface 20a of the workpiece 20 is a force f1, and the force that the second claw 10c of the movable claw 10 presses the end surface 22a of the workpiece 20 is a force f2. To do. Here, the directions of the forces f1 and f2 are directed from the movable claw 10 toward the fixed claw 11 (rightward in FIG. 9) with respect to the surface direction of the base 11a of the fixed claw 11 (for example, the vertical direction in FIG. 9). Tilted. Accordingly, the forces f1 and f2 respectively include force components f1a and f2a that work in the direction of pulling the workpiece 20 toward the chuck mechanism 1, and force components f1b and f2b that are directed radially outward of the workpiece 20.

  Here, the magnitudes of the force components f1b and f2b are determined by the frictional force between the first claw 10b of the movable claw 10 and the inner surface 20a of the work 20, and the second claw 10c of the movable claw 10 and the end face 22a of the work 20, respectively. Contributes to the magnitude of the frictional force between. These frictional forces all serve to prevent the workpiece 20 from coming off the chuck mechanism 1 and jumping forward (leftward in FIG. 9) when the workpiece 20 is rotated at a high speed while being fixed to the chuck mechanism 1. Fulfill. In a normal chuck mechanism, a workpiece is pressed toward the outer side in the radial direction against a substantially cylindrical workpiece. The pressing force in this case corresponds to the force components f1b and f2b in the present embodiment. In the present embodiment, in addition to these force components f1b and f2b, force components f1a and f2a exist. Since these force components f1a and f2a act in a direction to press the workpiece 20 against the chuck mechanism 1, the workpiece 20 is detached from the chuck mechanism 1 and moves forward (leftward in FIG. 8) in the same manner as the frictional force described above. Plays the role of preventing jumping out.

  In general, when the workpiece is rotated at a high speed while the workpiece is fixed to the chuck mechanism, a large centrifugal force acts on the workpiece. Since this centrifugal force works in the direction of increasing the inner diameter of the workpiece, the magnitude of the force with which the movable claw pushes the inner surface of the workpiece toward the outer peripheral side is larger than that when the workpiece is stationary. It becomes relatively small in the state of high-speed rotation. The magnitude of the frictional force between the workpiece and the movable claw is proportional to the force with which the movable claw pushes the inner surface of the workpiece toward the outer circumference, so that the workpiece and the movable claw move as the workpiece rotation speed increases. The frictional force between the nails is small. Therefore, the workpiece is easily detached from the chuck mechanism as the workpiece rotation speed increases.

  On the other hand, in the present embodiment, not only the frictional force but also force components f1a and f2a acting in the direction of pressing the workpiece 20 against the chuck mechanism side exist between the workpiece 20 and the movable claw 10. Therefore, when the workpiece 20 is rotated at a high speed, the magnitude of the force components f1a and f2a does not change even if the frictional force between the workpiece 20 and the movable claw 10 is reduced. 1 is prevented from jumping forward (leftward in FIG. 9). Furthermore, once the movable claw 10 is tilted to the base 11a side of the fixed claw 11 and is fixed in contact with the workpiece 20, there is no possibility that the movable claw 10 is tilted to the side opposite to the base 10a. This is because, in order to tilt the movable claw 10 tilted to the base 11a side of the fixed claw 11 to the side opposite to the base 11a, the portion of the workpiece 20 in contact with the first claw 10b of the movable claw 10 Since the diameter has to be increased, the movable claw 10 does not tilt to the side opposite to the base portion 10a.

  In the above embodiment, the movable claw 10 having a specific shape is used. However, the shape of the movable claw is not limited to this, and can be changed according to the shape of the workpiece. For example, for a substantially cylindrical workpiece 120 as shown in FIG. 10, a movable claw 110 having a first claw 110b and a second claw 110c formed at substantially the same height from the ridge line 110a can be used. Also in this case, when the chuck mechanism 1 is pressed against the workpiece 120, a frictional force is generated between the first claw 110b and the inner surface 120a of the workpiece 120 and between the second claw 110c and the inner surface 120a of the workpiece 120, respectively. work. Therefore, the movable claw 110 is fixed in a state where it is slightly rotated in the clockwise direction in FIG. 9 with the ridge line 110a as an axis. Accordingly, as in the above embodiment, the first claw 110b and the second claw 110c of the movable claw 110 respectively press the work 120 against the inner surface 120a of the work 120 toward the outer side in the radial direction of the work 120. It also presses in the direction of pressing toward the chuck mechanism along the axial direction.

  In addition, as shown in FIG. 11A, the shape of the movable claw 220 may be a substantially V-shaped shape obtained by bending a plate material at the ridgeline 220a in accordance with the shape of the workpiece. At this time, the length of the 1st nail | claw 220b and the 2nd nail | claw 220c may be the same, and one side may be long. Further, as shown in FIG. 11B, the shape of the movable claw 320 is a substantially Y-shaped shape having a support portion 320a extending on the other surface side at the center of the plate member whose both ends are bent to one surface side. Also good. Also at this time, the length of the 1st nail | claw 320b and the 2nd nail | claw 320c may be the same, or either one may be long. The shapes of these movable claws are examples, and other shapes may be used. Furthermore, the number of claws formed on the movable claws is not limited to two, and may include three or more claws. In the above embodiment, a groove is formed at the tip of the first claw of the movable claw, but this groove may not be formed, and a groove may be formed at the tip of the second claw. Good. Also, as shown in FIG. 12, a groove 420d may be formed at the tip of the first claw 420b and the second claw 420c of the movable claw 420 along a direction orthogonal to the thickness direction thereof. Alternatively, the extending direction of the groove is not limited to these and can be formed in any direction. Further, the extending directions of the grooves formed at the tips of the first and second claws may be the same or different. Further, the number of grooves to be formed is arbitrary. Furthermore, the support portion of the movable claw is not limited to the case where the movable claw includes a plate-like member bent as shown in the present embodiment, and the support portion is formed as a ridge line of the bent portion. As shown in FIG. 11 (b), it can have any shape.

  In the above embodiment, the size, material, shape, and arrangement of the fixed claws can be arbitrarily set in accordance with the shape and material of the workpiece. For example, even when the workpiece is not a substantially cylindrical or annular shape but a polygonal column shape, the nail material of the present invention can be used by adapting the shape of the fixed claw to the shape of the workpiece. Furthermore, although the case where the workpiece is gripped from the inside has been described as an example in the above embodiment, the movable claw 10 and the fixed claw 11 are also used when gripping the workpiece 520 from the outside, for example, as shown in FIG. The chuck mechanism of the present invention having the following can be used. Furthermore, in the present embodiment, the base portion of the fixed claw extends to the back surface of the movable claw, but it does not necessarily have to extend to the back surface of the movable claw, and has an arbitrary shape according to the shape of the workpiece. obtain.

  In the above embodiment, the chuck mechanism is attached to a lathe as a machine tool, but the machine tool including the chuck mechanism of the present invention is not limited to a lathe. In the lathe of the above embodiment, the workpiece is processed while rotating the workpiece fixed to the chuck mechanism at a high speed. However, the chuck mechanism of the present invention can also be used in a machine tool that processes a workpiece using a blade portion that moves at high speed in a state where the workpiece is fixed to the chuck mechanism, such as a milling machine and a machining center. Alternatively, the chuck mechanism of the present invention can be used for a machine tool including a lathe, a milling machine, or a machining center. In either case, since the work is fixed while being pressed against the stage side of the chuck mechanism, there is no possibility of the work jumping out to the opposite side of the stage during processing.

  Even when the workpiece gripped by the chuck mechanism of the present invention is rotating at a high speed, a force is applied to the stage side (rear) of the chuck mechanism. Therefore, even when the end surface on the stage side of the workpiece is cut, there is no possibility that the workpiece jumps forward. Therefore, it is possible to omit the step of changing the orientation of the workpiece when machining the back surface of the workpiece.

1 is a schematic view of a lathe according to an embodiment of the present invention. FIG. 2A is a front view of the chuck mechanism of the present invention, and FIG. 2B is a cross-sectional view taken along a broken line in FIG. FIG. 3 is a perspective view of the movable claw. FIG. 4 is a schematic diagram illustrating a state in which the movable claw is fixed to the fixed claw. Fig.5 (a) is a front view of the workpiece | work of this embodiment, FIG.5 (b) is a broken-line sectional view of Fig.5 (a). FIG. 6A is a schematic diagram showing a state in which the workpiece is temporarily fixed to the chuck mechanism, and FIG. 6B is a schematic diagram showing a state in which a stopper is used when pressing the chuck mechanism against the workpiece. It is. FIG. 7 is an enlarged schematic view of FIG. FIG. 8 is a schematic diagram showing the force acting on the movable claw in the state of FIG. FIG. 9 is a schematic view showing a state in which the workpiece is fixed to the chuck mechanism. FIG. 10 is a schematic diagram showing a movable claw adapted to a cylindrical workpiece. FIG. 11A is a schematic diagram illustrating a substantially V-shaped movable claw, and FIG. 11B is a schematic diagram illustrating a substantially Y-shaped movable claw. FIG. 12 is a perspective view showing a movable claw in which grooves extending in the thickness direction are formed in the first claw and the second claw. FIG. 13 is a schematic diagram illustrating a case where the chuck mechanism grips the workpiece from the outside.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Chuck mechanism 10 Movable claw 11 Fixed claw 12 Stage 13 Fixed stage 14 Movable stage 20 Work 41 Buffer member

Claims (15)

A chuck mechanism for gripping a workpiece,
Stage,
A fixed claw having a base fixed to the stage and a fixed claw extending from the base;
A movable claw provided between the workpiece and the fixed claw for gripping the workpiece, wherein the support claw is in contact with the fixed claw portion, the first claw is in contact with the first portion of the workpiece, and A second claw that comes into contact with a second part different from the first part of the workpiece, and the support part exists between the first claw and the second claw in the extending direction of the fixed claw part; With movable claws located,
The movable claw can be tilted toward the base side with the support portion as a center ,
The first claw is positioned closer to the base in the extending direction of the fixed claw than the second claw, and the distance between the support and the tip of the first claw is determined by the support and the second claw. The chuck mechanism is longer than the distance between the tip . The chuck mechanism according to claim 1, further comprising a buffer member between the movable claw and the base of the fixed claw, wherein a gap is formed between the movable claw and the base of the fixed claw. The chuck mechanism according to claim 1, wherein the support portion is located on a side closer to the second claw with respect to an extending direction of the fixed claw portion. The chuck mechanism according to any one of claims 1 to 3, wherein a groove is formed at a tip of one of the first claw and the second claw. The chuck mechanism according to claim 4, wherein the groove extends in a direction in which the fixed claw portion extends. The chuck mechanism according to claim 1, wherein the support portion is formed as a ridge line. The chuck mechanism according to claim 1, wherein the movable claw is attached to the base portion of the fixed claw so as to be movable in a surface direction of the base portion. The chuck mechanism according to claim 7, wherein the movable claw is rotatably attached to the base portion of the fixed claw in a plane parallel to the base portion. The said movable claw rotates centering | focusing on the said ridgeline to the said base side of the said fixed claw when the said fixed claw is urged | biased with respect to the said workpiece. Chuck mechanism. The chuck mechanism according to any one of claims 1 to 9, wherein the fixed claw includes a plurality of fixed claws, and a plurality of movable claws are attached to each fixed claw. The chuck mechanism according to claim 10, wherein each of the plurality of fixing claws has an arch shape and is arranged in a circumferential shape. A machine tool comprising the chuck mechanism according to any one of claims 1 to 11. The machine tool according to claim 12, wherein the machine tool includes any one of a lathe, a milling machine, and a machining center. A nail material used for a chuck mechanism for gripping a workpiece,
  A fixed claw having a base and a fixed claw extending from the base; and
  A movable claw provided between the workpiece and the fixed claw, a support portion that comes into contact with the fixed claw portion, a first claw that comes into contact with a first portion of the workpiece, and a first portion of the workpiece A second claw that abuts against a second portion different from the movable claw, wherein the movable claw is positioned such that the support portion exists between the first claw and the second claw in the extending direction of the fixed claw portion. Prepared,
The movable claw can tilt to the base side around the support part,
  The first claw is positioned closer to the base in the extending direction of the fixed claw than the second claw, and the distance between the support and the tip of the first claw is determined by the support and the second claw. Nail material longer than the distance between the tip of the. The claw material according to claim 14, wherein the fixed claw and the support portion are arched, and the workpiece is a cylindrical or annular workpiece.

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