JPH0333444B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a chuck for gripping a workpiece such as a crankshaft, which has an axial center portion and an eccentric portion. This invention relates to a chuck for holding an eccentric portion of a workpiece at an eccentric position deviated from the rotational center of the main body so as to position the eccentric portion of the workpiece at the rotational center of the chuck main body.

BACKGROUND TECHNOLOGY In general, this type of chuck has a grasping mechanism for grasping the axial center of the workpiece at a position offset from the rotation center of the chuck body, and a gripping mechanism for grasping the axial center of the workpiece at a position offset from the rotational center of the chuck body, and a gripping mechanism for grasping the axial center of the workpiece at a position offset from the rotation center of the chuck body. It is equipped with a phase determining mechanism for positioning the angular phase. The phase determining mechanism is conventionally disclosed in Japanese Utility Model Publication No. 56-49707, in which a pair of pawls for determining the angular phase of the workpiece are pivotally attached to the chuck body. A cylinder for operation is provided in the chuck body, and a piston of the cylinder slides to bring a pair of claws into contact with the eccentric part of the workpiece (hereinafter referred to as the former), and JP-A-59-59305
As disclosed in the publication, a fixed pawl and a movable pawl are provided on the front surface of the chuck body, a cylinder for operating the movable pawl is provided inside the chuck body in the direction of the center of rotation, and the piston of the cylinder A plurality of drawbars are connected to a plate that is operated by a drawbar, and movement of the drawbars in the axial direction moves the movable pawl to bring it into contact with the eccentric part of the workpiece (hereinafter the latter). ) is known.

Problems to be Solved by the Invention Regarding the former of the above conventional chucks,
Since each pawl is operated by an individual cylinder, there is a mutual difference in the movement of each pawl, resulting in poor phasing accuracy, and it is necessary to provide as many cylinders as there are pawls, making the structure complicated. Moreover, since the cylinders are disposed on both sides of the eccentric portion of the workpiece, there is a problem that the rotational balance is poor when the chuck body is rotated, making it difficult to increase the speed. In addition, in the case of the latter, since the cylinder for operating the jaws is arranged in the direction of the rotation center line, the length of the chuck body in the axial direction becomes long, resulting in poor rotation accuracy of the eccentric part of the workpiece. Moreover, since the cylinder is offset from the center of rotation of the chuck body to the same side as the gripping side of the eccentric portion, the rotational balance becomes poor when rotating the chuck body, making it difficult to increase the speed.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention integrally provides a mounting part located on the opposite side of the eccentric position to the chuck main body, and a piston is installed in the mounting part. is provided with a cylinder that can slide in the radial direction of the chuck body, and on the other hand, a phasing pawl is provided on the front surface of the chuck body, which comes into contact with the side surface of the eccentric part to determine the angular phase of the eccentric part with respect to the axial center part. The phasing claw is provided so as to be centrifugally movable toward the side surface of the eccentric portion, and by sliding the locating claw and the piston of the cylinder in the outward radial direction of the piston, the phasing claw approaches the side surface of the eccentric portion, and the phasing claw is moved toward the radial center of the piston. It is characterized by being connected by a connecting means that moves the phase determining pawl away from the side surface of the eccentric part by sliding on the eccentric part.

Function The above structure positions the axial center of the workpiece at the eccentric position of the chuck body, turns the eccentric part toward the rotation center of the chuck body, and then moves the piston of the cylinder to the outer peripheral end of the chuck body. When it is slid, the phasing claw moves toward the side surface of the eccentric portion and comes into contact with the side surface of the eccentric portion, positions the angular phase of the eccentric portion with respect to the axial portion, and grips the axial portion in this state. . Next, when the chuck main body is rotated to process the eccentric portion of the workpiece, centrifugal force acts on the piston, and the centrifugal force causes the phasing pawl to strongly press and hold the side surface of the eccentric portion. Further, when the chuck body is rotated, since the cylinder is provided at a position opposite to the deflection side of the part that grips the axial center of the workpiece, the rotational balance of the chuck as a whole is improved.

Embodiment FIGS. 1 to 3 show a first embodiment, in which a crank arm portion 1b that grips a crank journal portion 1a that is an axial center portion of a crankshaft 1 illustrated as a workpiece and is an eccentric portion. The angle phase of the crank pin 1c with respect to the crank journal portion 1a is determined, and the crank pin 1c is positioned at the center of rotation of the chuck. In the drawings, reference numeral 2 denotes a chuck body which can be fixed to the spindle of a machine tool, and is constructed by integrally joining a front member 3 and a rear member 4. The front member 3 has a substantially rectangular recess 5 on its front surface, which is offset to one side (downward in FIG. 1) with respect to the rotation center of the chuck body 2, and the recess 5 is offset. There is a receiving part 3a on the position side,
Mounting portions 3b are provided on the opposite side of the recessed portion 5 from the deflection side. A receiver fitting groove 6 is formed on the recess 5 side of the receiving part 3a, and the receiver fitting groove 6
A receiver 7 is fitted into the holder 7. This receiver 7 has mounting flanges 7a on both sides of its front end, and the mounting flanges 7a are screwed to the front surface of the front member 3.
Further, the receiver 7 has a block fitting groove 7b formed on the side of the recess 5, and two V blocks 8 and 9 for receiving the crank journal portion 1a of the crankshaft 1 are fitted into the block fitting groove 7b. It is removably screwed to the receiver 7. These V-blocks 8, 9 can be replaced with different V-blocks when the shape, size, etc. of the crankshaft 1 is changed. A stopper 10 for determining the axial position of the crankshaft 1 is removably screwed onto the front surface of the receiver 7. Next, on the front surface of the front member 3, a pair of pawl fitting grooves 11 are formed in a substantially radial direction toward the space in which the crank journal portion 1a supported on the V blocks 8, 9 is placed. Claws 12 are slidably fitted into the grooves 11, respectively. This claw 12 is composed of a main claw 13, a claw support 14 removably fixed to the inner end surface of the main claw 13, and a gripping claw 15 pivotally attached to the claw support 14. is fitted into the pawl fitting groove 11.
The gripping claw 15 has gripping portions 15a and 15b facing the V blocks 8 and 9, as shown in FIG.
The crank journal portion 1a can be gripped between the V blocks 8 and 9. An engagement hole 16 is formed on the rear surface of the parent claw 13, and a wedge surface 16a is formed on the inner surface of the engagement hole 16 on the tip side of the parent claw. A sliding hole 17 is formed in the center of the chuck body 2, and a storage space 18 is formed in the chuck body 2, with the sliding hole 17 at the center. The slide hole 17 has a draw screw 19.
is fitted so as to be slidable in the axial direction. This draw screw 19 is connected to a draw bar that is moved by a rotating cylinder or the like, so that it can be moved in the axial direction. A central portion of a plate-shaped spider 20 located within the storage space 18 is fixed to the draw screw 19. In addition, the front member 3 is formed with axial insertion holes 21 at positions facing the engagement holes 16 of the master claws 13, and the actuating bars 22 are slidable in the axial direction into these insertion holes 21. It is inserted. The above operating bar 22
The rear end surface is connected to the front surface of the spider 20 by a connecting nut 23 and a disc spring 23a, and the tip of the actuation bar 22 is inserted into the engagement hole 16, and the wedge surface formed at the tip of the actuation bar 22 is inserted into the engagement hole 16. 22a is engaged with the wedge surface 16a of the master claw 13.

Next, mounting boards 24 are removably screwed onto the front surface of the chuck main body 2 at positions covering the main claws 13, and both ends of a pivot frame 25 are fixed to these mounting boards 24, respectively. There is. Support grooves 26 are formed near both ends on the rear surface of the pivot frame 25, and phase determining pawls 27 are formed in these support grooves 26.
The bases of the phasing claws 2 are fitted into each other, and their phasing claws 2
7 is pivotally connected to the pivot frame 25 by an axial pin 28. Both phase determining claws 27 are
The crank journal portion 1a is connected to the V block 8,
9 and directs the crank pin 1c toward the rotation center of the chuck body 1, the crank arm 1b
It has abutting parts 27a that can be moved near and far toward the sides of the storage space, and these abutting parts 27a abut on both sides of the crank arm part 1b, respectively, and sandwich the crank arm part 1b from both sides. Yotsute crank pin 1
The angular phase of c with respect to the crank journal portion 1a is determined. Also, in the mounting portion 3b of the chuck body 1, there is a pneumatically or hydraulically operated cylinder 2 for operating both the phase determining pawls 27.
9 is provided. This cylinder 29 has a cylinder hole 30 having an axis in the radial direction of the chuck body 2 on the outer periphery of the mounting portion 3b, a piston 31 is slidably fitted into the cylinder hole 30, and the cylinder hole 30 is connected to the cover plate 32. It is constructed by twisting and closing it. The axis of the cylinder 29 is set to coincide with an extension of a line connecting the center of rotation of the chuck body 2 and the space in which the crank journal portion 1a is placed when viewed from the front. The piston 31 of the cylinder 29 is connected to a pressure fluid such as compressed air or pressure oil supplied and discharged from a supply and discharge passage 33 provided in the chuck body 2 and the draw screw 19 and a supply and discharge passage 34 provided in the chuck body 2. It is designed to be twisted and slid. A piston 31 of the cylinder 29 is connected to a connecting means 35 to the phase determining pawl 27.
The abutting portion 27 of the phasing pawl 27 is
a towards the side of the space where the crank arm 1b of the crankshaft 1 supported by the V-blocks 8 and 9 is moved, and by sliding in the radial center direction of the piston 31, the phasing pawl 27 is moved toward the crank arm. It is configured to be kept away from the side of the storage space of 1b. In the connecting means 35, 36 is an arm integrally provided at the base of the phasing claw 27 so as to protrude to the side opposite to the tip side of the phasing claw 27, the tip of which is attached to the wedge surface of the movable body to be described later. They are urged by a spring 37 to come into contact. Although this spring 37 is constituted by a torsion spring supported by a pin 38 on the mounting board 24, it may also be constituted by a coil spring stretched between the two arms 36. Reference numeral 39 denotes a notched window formed on the front surface of the chuck body 2 so as to face the side surface of the piston 31, and the movable body 40 is fixed to the side surface of the piston 31 through this notched window 39. This movable body 40 has wedge surfaces 40a formed on both sides. The pair of wedge surfaces 40a and the pair of phase determining claws 27 are connected to the chuck body 2.
It is formed symmetrically with respect to the axis of the cylinder 29 when viewed from the front, and the pair of phase determining pawls 27 are rotated symmetrically as the piston 31 slides. Note that 41 is a closing plate attached to the movable body 40, and 42 is a closing plate that closes the sliding hole 17.

In the case of the above structure, when gripping the crank journal portion 1a of the crankshaft 1 and machining the crank pin portion 1c, first the V blocks 8, 9, the stopper 10, the gripping claw 15, and the phase determining claw 27 are attached to the crankshaft 1. It is replaced with one corresponding to the shape and size of the crankshaft 1. In this case, the V-blocks 8 and 9 are aligned with the axis of the crank pin portion 1c when the crank arm portion 1b is accurately directed toward the rotation center of the chuck body 2 while receiving the crank journal portion 1a of the crankshaft 1. is replaced with one designed to coincide with the rotation center of the chuck body 2. In addition, the stopper 10 is replaced with one designed so that when the crank arm 1b is received, the axial position of the crank pin 1c is within a preferable machining range. Furthermore, the gripping claw 15 is replaced with one designed to be able to grip the crank journal portion 1a between the V-blocks 8 and 9. This gripping claw 15 can be replaced by removing the claw support 14 from the main claw 13.
Do this together with 4. Further, when the phase determining pawls 27 are moved close to each other by the movable body 40 and grip the crank arm portion 1b from both sides, the crank pin portion 1c
It is replaced with one designed to be accurately directed toward the rotation center of the chuck body 2. This replacement of the phase determining claws 27 is carried out together with the mounting boards 24 after the mounting boards 24 are removed.

Next, insert the crank journal portion 1a of the crankshaft 1 into the recess 5 from the front of the chuck body 2.
The crank journal portion 1a is placed on the receiving surfaces of the V blocks 8 and 9 and supported. Next, pressurized fluid is supplied from the supply/discharge path 33 to cause the piston 31 of the cylinder 29 to slide radially outward of the chuck body 2, and the piston 31 moves toward the movable body 40.
integrally move radially outward. This movement of the movable body 40 causes the wedge surfaces 4 on both sides of the movable body 40 to
0a rotates the pair of arms 36 symmetrically against the spring 37, thereby rotating the pair of phasing claws 27.
are rotated about the pin 28 in a direction toward each other, and the abutting portions 27 of these phasing claws 27
a is the crank arm portion 1b of the crankshaft 1;
The crank arm 1b is held between the two sides by abutting on both sides of the crank arm 1b. Therefore, crankshaft 1
The angular phase of the crank arm portion 1b is accurately positioned, whereby the crank pin portion 1c is accurately directed toward the rotation center of the chuck body 2, and its axis coincides with the rotation center of the chuck body 2. Thereafter, the rotary cylinder is actuated to slide the draw screw 19 forward and move the spider 20 forward. This forward movement of the spider 20 causes the two drawbars 22 to slide forward, and the wedge surfaces 22a of the drawbars 22 press the master claw 13 toward the radial center. As these master claws 13 move, the contact portion 15a of the gripping claw 15 contacts the crank journal portion 1a on the V blocks 8, 9, and the crank journal portion 1a is securely gripped between the V blocks 8, 9. do.

Next, the chuck body 2 is rotated to perform cutting work on the crank pin portion 1c. In this case, when the chuck main body 2 is rotated, centrifugal force acts on the piston 31 of the cylinder 29, strongly pressing the abutment part 27a of the phasing pawl 27 against the side surface of the crank arm 1b. Ensures angular phase is held in place. In addition, when processing the crank pin portion 1c by rotating the chuck body 2 as described above, the crank journal portion 1a is attached to the chuck body 2.
The mounting portion 3b is located on the opposite side of the deviation side of the remaining position.
Since the cylinder 29 is provided in the mounting portion 3b, the overall rotational balance between the chuck and the crankshaft 1 is improved, and it is possible to increase the rotational speed and improve the machining accuracy. Further, since the cylinder 29 is provided in the mounting portion 3b in the radial direction of the chuck body 2, the axial dimension of the chuck body 2 can be reduced, and the rotation of the crank pin portion 1c can be stabilized. crankshaft 1
To remove the chuck, slide the draw screw 19 backward to open the gripping claw 15, and supply pressurized fluid from the supply/discharge path 34 to slide the piston 31 toward the center of the chuck to open the phasing claw 27. open.

4 and 5 show the second embodiment of the present application,
Claws 45 are used instead of the V blocks 8 and 9 in the above embodiment.
is provided so as to be slidable in the radial direction, and is configured to be slidable in the radial direction in the same manner as the pawl 12e. The stopper 10e is removably fixed to the front surface of the chuck body 2e. Further, instead of one of the phase determining pawls 27 of the above embodiment, a fixed pawl 46 is removably fixed to the front surface of the chuck main body 2e, and the fixed pawl 46 and the phase determining pawl 27e are connected to the crank arm portion 1.
The angular phase of the crank arm 1be is determined by sandwiching be. In addition, the connecting means 3
5e is configured by providing an oblique elongated hole 47 at the tip of the arm 36e, providing an engaging convex portion 48 on the movable body 40e, and engaging the engaging convex portion 48 with the oblique elongated hole 47. The phase determining pawl 27 can be rotated by sliding the piston 31e of the piston 29e. Note that the oblique elongated hole 47 may be provided on the movable body 40e, and the engaging convex portion 48 may be provided on the arm 36e. In this embodiment, the angular phase of the crank arm 1be is determined with the crank journal part 1ae placed on the receiving part 10ae of the stopper 10e, and then the crank journal part 1ae is gripped by the three claws 12e and 45. In this case, the crank arm 1be is slightly moved toward the center of rotation by sliding on the portion gripped by the phase determining pawl 27e. It should be noted that the same or equivalent constituent parts as in the first embodiment are given the same reference numerals as the corresponding parts with an alphanumeric letter "e" to omit redundant explanations, and in the following third embodiment, the alphabetic letters "e" are also used in the same manner. The redundant explanation will be omitted by adding f.

FIG. 6 shows a third embodiment of the present application, in which a movable body 40f is provided with an inclined groove 49, an arm 36f is provided with an engaging convex portion 50, and the engaging convex portion 50 is provided with an inclined groove 49.
The connecting means 35f is configured by engaging with the connecting member 9. Note that the inclined groove 49f may be provided on the arm 36f, and the engagement convex portion 50 may be provided on the movable body 40f, respectively.

In each of the above embodiments, the phasing pawl is rotatably mounted on the front surface of the chuck body, and the angular phase of the workpiece is determined by rotating the phasing pawl with the movement of the piston. , the phase determining pawl can be smoothly rotated by a simple connecting means. In addition, since the phase determining pawl is removably attached to the front of the chuck body, the degree of freedom in designing the chuck as a whole is increased, making it easier to downsize, and making setup changes easier and faster. It has the advantage of being suitable for low-volume production.

Effects of the Invention As described above, in the present invention, a phase determining pawl is movably provided on the front surface of the chuck body, and the phase determining pawl is moved by a cylinder to abut against the side surface of the eccentric part of the workpiece. Since the angular phase of the eccentric part with respect to the axis can be determined, the eccentric part of the workpiece can be accurately positioned at the rotation center of the chuck body, and the eccentric part can be machined well. Can be done. In addition, the chuck body is provided with a mounting part located on the opposite side of the eccentric position that holds the axial center of the workpiece, and the above-mentioned cylinder is provided in the mounting part, so that the workpiece can be gripped. When rotating the chuck, the overall rotational balance between the chuck and the workpiece can be improved, and the chuck has the advantage of being able to easily speed up and stabilize the rotation. Also, since the cylinder is installed in the mounting part so that the piston slides in the radial direction of the chuck body,
The thickness of the chuck body in the axial direction can be reduced, thereby increasing the speed of rotation of the chuck and significantly improving productivity. Moreover, as mentioned above, the cylinder is provided in the radial direction, and the phasing claw is moved toward the side surface of the eccentric part of the workpiece by sliding the piston in the radial direction, so that the rotation of the chuck body is The accompanying centrifugal force of the piston allows the phasing pawl to strongly contact the side surface of the eccentric portion, which has the effect of reliably determining the angular phase of the eccentric portion.

[Brief explanation of the drawing]

The drawings show an embodiment of the present application, and FIG. 1 is a front view, FIG. 2 is a partially cutaway sectional view taken along the line 1, FIG. 3 is a partially cutaway sectional view of the main part, and FIG. FIG. 4 is a front view showing the second embodiment, FIG. 5 is a partially cutaway cross-sectional view taken along the - line, and FIG. 6 is a partial view showing the third embodiment. 1... Crankshaft (workpiece), 1a
...Crank journal part (shaft center part), 1b...
Crank arm (eccentric part), 2...chuck body,
3b... Mounting part, 29... Cylinder, 27...
Phasing claw, 31...piston, 35...coupling means.

Claims (1)

[Scope of Claims] 1. In order to position the eccentric part of a workpiece having an axial center part and an eccentric part at the rotation center of the chuck body, an eccentricity in which the axial center part of the workpiece is deviated from the rotation center. In the chuck which can be held in position, the chuck body is integrally provided with a mounting part located on the opposite side of the eccentric position, and the piston is mounted in the mounting part in the radial direction of the chuck body. A slidable cylinder is provided, and a phasing pawl is provided on the front side of the chuck body, and a phasing pawl that comes into contact with the side surface of the eccentric portion to determine the angular phase of the eccentric portion with respect to the axial center portion is oriented toward the side surface of the eccentric portion. The phasing claw is provided so as to be movable near and far, and the phasing claw is brought into contact with the side surface of the eccentric portion by sliding the phasing claw and the piston of the cylinder in the radial direction of the piston, and the phasing claw is brought into contact with the side surface of the eccentric part, and the phasing claw is slid in the radial center direction of the piston. A chuck characterized in that the chuck is connected by a connecting means which moves the phase determining pawl away from the side surface of the eccentric part. 2. A pair of phase determining pawls are rotatably mounted on the front surface of the chuck body, and the phase determining pawls contact both sides of the eccentric portion to determine the angular phase of the eccentric portion. A chuck according to claim 1, characterized in that: 3 One phase determining pawl is rotatably pivotally mounted on the front surface of the chuck body, and the phase determining pawl contacts one side of the eccentric part and the other side of the eccentric part is connected to a fixed pawl provided on the chuck body. 2. The chuck according to claim 1, wherein the chuck is configured to determine the angular phase of the eccentric portion by bringing the chuck into contact with the chuck. 4 An arm is integrally provided at the pivot point of the phase determining claw,
A movable body that is integrally moved by a piston of a cylinder is arranged on the front of the chuck body, and the tip of the arm is connected by a spring in contact with a wedge surface formed on the side of the movable body. The chuck according to claim 2 or 3, characterized in that it constitutes means. 5 An arm is integrally provided at the pivot point of the phase determining claw,
A movable plate that is integrally moved by a piston of a cylinder is disposed on the front surface of the chuck body, and an inclined groove or oblong hole is formed in either one of the movable body and the tip of the arm, and the other is engaged with the movable plate. The chuck according to claim 2 or 3, characterized in that the connecting means is constructed by providing a convex portion and engaging the engaging convex portion with the inclined groove or the oblique elongated hole. 6. The chuck according to claim 2 or 3, wherein the phase determining pawl and the movable body are each removably provided on the chuck main body, so that different phase determining pawls and movable body can be replaced.