JP3857912B2 - Diaphragm air chuck - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a diaphragm type air chuck for small-diameter workpieces.
[0002]
[Prior art]
Conventionally, in a diaphragm type air chuck, as shown in Japanese Patent No. 3023769 and Japanese Patent Application Laid-Open No. 5-345207, etc., a plurality of gripping claws are projected from a diaphragm, a piston is connected to the diaphragm, and the piston is air-operated. By driving, the diaphragm is bent, the gripping claw is opened and closed by this bending, and the workpiece is grasped or released by the gripping claw.
Conventionally, in a collet chuck, as shown in Japanese Patent Application Laid-Open No. 2000-33503, etc., it has been widely performed to clamp a work using a pull bar.
[0003]
[Problems to be solved by the invention]
Compared to the collet chuck, the diaphragm type air chuck is superior in gripping the workpiece at high speed. Therefore, a diaphragm type air chuck is used when a workpiece is rotated at high speed to perform precise machining.
However, in the diaphragm type air chuck, when clamping a small-diameter workpiece with the small-diameter gripping part of the claw with an open inner diameter, the gripping force at the tip of the elongated small-diameter gripping part is reduced due to insufficient rigidity of the claw itself. It becomes insufficient compared with grasping power. For this reason, when a small-diameter workpiece is clamped with a claw with an inner diameter opening, a sufficient uniform gripping force cannot be obtained over the entire length of the small-diameter gripping part, so that the chuck rotation speed cannot be increased sufficiently. It was.
The present invention aims to solve the above problems.
[0004]
[Means for Solving the Problems]
In order to achieve the above-mentioned problems, the present invention is a diaphragm type air chuck for detachably attaching to a spindle or the like of a machine tool, the main body 2 having a piston arrangement space portion 8 formed in an inner diameter portion, A pulling piston 10 slidably arranged in the axial direction in the piston arrangement space 8, chuck opening / closing pistons 12, 14 arranged slidable in the axial direction in the piston arrangement space 8, and an outer diameter portion A diaphragm 4 fixed to the main body 2 and having a central portion connected to the chuck opening / closing pistons 12 and 14, a plurality of gripping claws 28 a are arranged in a ring shape, and an outer diameter portion of each gripping claw 28 a is connected to the diaphragm 4. A formed claw 28 which is attached to the center and has an elongated small-diameter gripping portion 30 for gripping a small-diameter workpiece formed in a predetermined length, and is formed at the center of the molding claw 28. A rod insertion hole 32 having an end opened on the rear surface of the forming claw 28 and the other end opened on the front end surface of the small-diameter gripping portion 30 and an engagement receiving portion 32a formed in the opening, and a rear portion for the pulling An engagement portion 24a is connected to the central portion of the pistons 12 and 14 and the distal end portion and the vicinity thereof are slidably inserted into the rod insertion hole 32 of the forming claw 28 and formed at the distal end portion. A pulling rod 24 that engages with the portion 32a, and an air passage 34 that is connected to an air pressure feeding device and that feeds air into the piston arrangement space 8 to drive the pulling piston 10 and the chuck opening and closing pistons 12 and 14. , 36.
In the present invention, the engaging portion (24a) at the tip of the pulling rod (24) and the engaging receiving portion (32a) of the rod insertion hole (32) are tapered surfaces.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
Reference numeral 2 denotes a chuck body that is detachably attached to an end face of a rotating spindle (spindle) of a machine tool, and is composed of a cylindrical housing 2a and a disk-like base 2b fixed integrally therewith. ing.
[0006]
The outer diameter portion of the diaphragm 4 is fixed to one end face of the housing 2 a, and the outer diameter portion of the stopper plate 6 is fixed to the diaphragm 4. A piston arrangement space portion 8 is formed on the inner diameter side of the housing 2a, and a pulling piston 10, a first chuck opening / closing piston 12, and a second chuck opening / closing piston 14 are arranged in this space portion. Yes. The tubular inner diameter portions of the pistons 12 and 14 and the diaphragm 4 are connected to each other by bolts 16.
[0007]
The outer peripheral surfaces of the pistons 10, 12, and 14 are slidably fitted into the cylinder wall of the housing 2a so as to be slidable. The columnar shaft portion 18a of the cradle 18 having the same diameter as that of the shaft portion 10a is coaxially fixed to the end surface of the columnar shaft portion 10a of the pulling piston 10. The shaft portion 10a of the pulling piston 10 and the shaft portion 18a of the cradle 18 constitute a cylindrical piston guide, and the inner diameter portions of the chuck opening / closing pistons 12 and 14 and the diaphragm 4 are sealed. It is slidably fitted to.
[0008]
The housing 2a is formed with a disk-shaped partition wall 2c integrally therewith, and the outer peripheral surface of the tubular inner diameter portion of the chuck opening / closing piston 14 is slidably fitted in a sealing manner on the inner peripheral surface of the partition wall 2c. Match. Reference numeral 20 denotes a shift liner, the outer peripheral portion of which is fixed to the inner peripheral surface of the outer diameter portion of the diaphragm 4, and the inner diameter portion of the shift liner is fitted slidably and slidably into the outer peripheral surface of the tubular inner diameter portion of the diaphragm 4. . An attachment hole 22 is formed in the center of the cradle 18 in the axial direction, and the other end of the pull bar 24 having an engagement portion 2a formed of a tapered portion at the tip is inserted into the attachment hole 22, and the pull The rear part of the rod 24 is fixed to the cradle 18 by a set screw 26.
[0009]
Reference numeral 28 denotes a formed claw composed of a plurality of gripping claws 28a, and each gripping claw 28a is fixed separately so that a hole is formed inside in a state of being connected in a ring shape by a connecting body. The small-diameter gripping portion 30 for small-diameter workpieces of the formed pawl 28 constituted by the elongated projections of the plurality of gripping claws 28a is configured in an elongated shape as a whole. A rod insertion hole 32 is formed at the center of the molding claw 28, one end of the rod insertion hole 32 is opened at the rear surface of the molding claw 28, and the other end is opened at the tip of the small diameter gripping portion 30. Yes. An engagement receiving portion 32a is formed at the tip of the rod insertion hole 32. The engagement receiving portion 32a is formed of a taper portion having the same shape as the taper portion of the engagement portion 24a at the tip of the pull rod.
[0010]
The pulling rod 24 protruding from the cradle 18 is slidably inserted into the rod body insertion hole 32 so that the engaging portion 24a and the engaging receiving portion 32a are brought into contact with each other. Air passages 34 and 36 are formed in the chuck body 2, the air passage 34 communicates with the cylinder chambers 38 and 40, and the air passage 36 communicates with the cylinder chambers 42, 44 and 46. The air passages 34 and 36 communicate with an air pressure feeding device (not shown).
[0011]
Next, the operation of this embodiment will be described.
In FIG. 1, in a state where the inner diameter portion of the diaphragm 4 is pushed rightward by the pistons 12, 14, the forming claw 28 is expanded, and the inner diameter portion of the diaphragm 4 is pushed leftward by the pistons 12, 14. In this state, the forming claw 28 is closed. The small-diameter gripping portion 30 of the forming claw 28 is fitted with a small-diameter hole portion of a work (not shown) corresponding to the diameter of the forming claw 28. When the forming claw 28 is opened, the work is clamped to the forming claw 28. When 28 is closed, the clamped state with the forming claw 28 is released.
[0012]
When the work is clamped on the forming claw 28, air is pumped into the cylinder chambers 38 and 40, and the pistons 12 and 14 are driven rightward in the drawing. When the pistons 12 and 14 are driven in the right direction, the inner diameter portion of the diaphragm 4 connected to the pistons 12 and 14 moves in the right direction, and the molding claws 28 are opened. Simultaneously with the opening of the forming claw 28, the pulling piston 10 is driven leftward in the figure by the air pressure in the cylinder chamber 40, and the pulling rod 24 is pulled leftward in the figure. As a result, the taper surface of the engagement portion 24a of the tension bar 24 strongly presses against the taper surface of the engagement receiving portion 32a of the rod insertion hole 32 of the forming claw 28, and the small diameter gripping portion 30 of the forming claw 28 is pressed. A further opening force is applied to the tip from the engaging portion 24a of the pull bar 24.
[0013]
As a result, a uniform strong spreading force is generated in the small diameter gripping portion 30 from the root 30a to the tip 30b with respect to the inner diameter portion of the workpiece, and the work is firmly clamped on the small diameter gripping portion 30. The When releasing the clamped state of the workpiece, air is pumped from the air passage 36 to the cylinder chambers 42, 44, 46, the inner diameter portion of the diaphragm 4 is driven leftward in the figure, and the pulling piston 10 is moved rightward. To drive. As a result, the forming claw 28 is closed, and at the same time, the tension bar 24 protrudes and moves in the right direction, so that the engagement portion 24a of the tension bar 24 moves from the engagement receiving portion 32a of the rod body insertion hole 32 of the molding claw 28. The workpiece is unclamped.
[0014]
【The invention's effect】
In the present invention, as described above, the engaging portion of the pulling rod is engaged with the tip of the elongated small-diameter gripping portion of the formed claw that opens and closes by the deformation of the diaphragm driven by air pressure, and the pulling rod engages the small-diameter gripping portion. Since the tip is pressurized in the spreading direction, the spreading force at the tip of the small diameter gripping part is increased, and a uniform and powerful workpiece gripping force is applied over the entire length from the root of the small diameter gripping part to the tip. The inner diameter portion of the small-diameter workpiece can be reliably grasped.
[Brief description of the drawings]
FIG. 1 is a sectional view of a diaphragm type air chuck according to the present invention.
FIG. 2 is a front view of a forming nail.
[Explanation of symbols]
2 Chuck body 2a Housing 2b Base 2c Bulkhead 4 Diaphragm 6 Stopper plate 8 Piston arrangement space 10 Pulling piston 10a Shaft 12 Chuck opening / closing piston 14 Chuck opening / closing piston 16 Bolt 18 Receptacle 18a Shaft 20 Shift liner 22 Mounting hole 24 Pulling rod 24a engaging portion 26 set screw 28 molding claw 28a gripping claw 30 small diameter gripping portion 32 rod body insertion hole 32a engagement receiving portion 34 air passage 36 air passage 38 cylinder chamber 40 cylinder chamber 42 cylinder chamber 44 cylinder chamber 46 cylinder chamber

Claims (2)

A diaphragm type air chuck for detachably attaching to a spindle or the like of a machine tool, wherein a main body (2) having a piston arrangement space portion (8) formed in an inner diameter portion, and the piston arrangement space portion (8) A pulling piston (10) slidably disposed in the axial direction, a chuck opening / closing piston (12) (14) slidably disposed in the axial direction in the piston arrangement space (8), and an outer diameter portion Is fixed to the main body (2), and a diaphragm (4) whose central portion is connected to the chuck opening / closing piston (12) (14) and a plurality of gripping claws (28a) are arranged in a ring shape, and each gripping claw (28a) an outer diameter portion attached to the diaphragm (4), and a formed claw (28) in which an elongated small-diameter gripping portion (30) for gripping a small-diameter workpiece is formed at a central portion at a predetermined length; One end is formed in the center of the claw (28) and opened at the rear surface of the molded claw (28), the other end is opened at the front end surface of the small diameter gripping portion (30), and an engagement receiving portion (32a) is formed in the opening. The formed rod body insertion hole (32) and the rear part are connected to the central part of the pulling piston (12) (14), and the tip part and the vicinity thereof are the rod body insertion hole (32) of the forming claw (28). ) Is slidably inserted into the engagement portion (24a) formed at the distal end portion, and is connected to the pulling rod (24) engaged with the engagement receiving portion (32a) and the air pressure feeder, and the piston arrangement An air passage (34) (36) for driving the tension piston (10) and the chuck opening / closing pistons (12) (14) by pumping air into the space (8) is provided. Diaphragm air chuck. The engagement portion (24a) at the distal end of the pull rod (24) and the engagement receiving portion (32a) of the rod body insertion hole (32) are tapered surfaces. Diamond air chuck.

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