JPH04300110A - Chuck - Google Patents

Abstract

PURPOSE:To drive a work holding claw in the work holding or work releasing direction under work pressure of fluid. CONSTITUTION:A piston 8 driven by means of a fluid, for example, air pressure, is stored and arranged in a piston storing space of a base 1 and base cover 2 arranged detachably on a spindle, etc., of a machine tool. The outer portion of a work disk 16 on which work holding claws 17 and 18 are provided is fixed to the base cover 2, and the center portion of the work disk 16 is connected to the piston 8. A preliminary compressive force is given to the work disk 16 in radial inner direction, and the disk bent in either one of the two directions is considered to be stabilized. The bent direction of the work disk 16 is transformed by driving the piston 8. When the work disk 16 is driven from a condition in which the disk is bent in one direction to a neutral condition, i.e., to a degree that the disk in flat condition is bent slightly toward the other side, it is bent to the other side by its own elasticity.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chuck used in machining.

0002

[Prior Art] A tube for pumping air is attached to a base that is removably attached to the spindle of a machine tool or a base that is attached to a fixed bed, and a passage that is open to the outside of the base on the side opposite to the side where the spindle is attached is attached. The edge of a diaphragm, which has a thick edge and a plurality of work gripping claws integrally protruding from the outer surface of the thin wall, is fixed to the edge of the outer surface of the base, and is connected to the inner surface of the thin wall of the diaphragm. A workpiece gripping jig for machining, that is, an air chuck, in which the passage faces the sealed space between the outer surfaces of the base, is disclosed in Utility Model Application Publication No. 2-53313 and Japanese Patent Application Publication No. 2-269513.
It is disclosed in the publication No.

0003

[Problems to be Solved by the Invention] The above-mentioned air chuck pressurizes a plate-shaped diaphragm with air, deforms the diaphragm in a curved direction by the pressure of this air, and drives the workpiece gripping claw in the direction of gripping or releasing the workpiece. are doing.

[0004] Therefore, a large air pressure is required to deform the diaphragm, and a large air pressure feeding device or a pressure increase valve is required, resulting in an increase in the size and cost of the device. The present invention aims to eliminate the above-mentioned defects.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a base 1 which is detachably attached to a spindle of a machine tool and has a cylinder wall 1a formed on the inner diameter thereof, and a base 1 which is fixed to the base 1. a base cover 2 forming a fluid space between it and the base 1; and a piston 8 slidably fitted to the cylinder wall 1a and disposed within the fluid space.
and a fluid tube 4 attached to the base 1 that pumps fluid to both sides of the piston 8, and a fluid tube 4 which is precompressed in the diametrical direction and curved so as to have a stable state in two directions, and whose outer diameter part is The actuating plate 16 is fixed to the base cover 2 and has a central portion connected to the piston 8, and workpiece gripping claws 17, 18 provided on the actuating plate 16.

[0006]

[Operation] The force for gripping the workpiece is determined by the elasticity of the actuating plate 16 itself in the direction of curvature. When the actuating plate 16 is deformed in the workpiece gripping direction or the workpiece gripping direction, the piston 28 is driven by fluid pressure, and the actuating plate 16 is deformed from the one-sided bent state to the neutral state. The actuating plate 16 is
If you cross this neutral state even slightly,
The work gripping claw 1 bends to the other side due to its own elasticity.
7 and 18 are displaced in the direction of gripping or releasing the workpiece.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be explained in detail below with reference to embodiments shown in the accompanying drawings. Reference numeral 1 denotes a base that is detachably attached to the end face of the main shaft of a machine tool, and a cylinder wall 1a is formed in the cylindrical portion of this base. At the end of the cylindrical part of the base 1, there is a disc-shaped base cover 2 with a hole formed in the center.
is fixed. A piston storage space is formed between the base 1 and the base cover 2.

Reference numeral 3 denotes a cylindrical body whose flange is fixed to the base 1 with screws, and is loosely fitted into a hole formed in the center of the base 1 and the base cover 2. The cylinder body 3
A small diameter portion 3 a is formed on one side of the base cover 2 , and the small diameter portion 3 a projects laterally of the base cover 2 .

4 is a fluid tube, and an outer cylindrical portion 4a
It has a triple structure of a middle cylindrical part 4b and an inner cylindrical part 4c,
A threaded portion formed on the outer peripheral surface of the outer cylindrical portion 4a is tightly screwed into a threaded portion formed on the inner diameter portion of the cylindrical body 3.

[0010] The inner cylindrical portion 4c is connected to the cylindrical portion 4a,
The outer peripheral surface of the tip of the cylindrical portion 4c protrudes from the cylindrical portion 4b and is fitted into the inner diameter portion of the cylindrical body 3 in a sealed manner. A space between the inner circumferential surface of the outer cylindrical portion 4a and the outer circumferential surface of the middle cylindrical portion 4b constitutes a first fluid pressure passage 5, and
A second fluid pressure passage 6 is formed between the inner circumferential surface of the inner cylindrical portion 4c and the outer circumferential surface of the inner cylindrical portion 4c. The fluid pressure feeding paths 5 and 6 communicate with a fluid pressure feeding device (not shown) consisting of an air pressure feeding device. An oil passage is formed inside the inner cylindrical portion 4c.

Reference numeral 7 denotes a work stopper, the tubular portion of which is screwed into the small diameter portion 3a of the cylindrical body 3, and the tubular portion communicates with the inside of the inner cylindrical portion 4c. Reference numeral 8 denotes a piston, the outer peripheral surface of which is slidably fitted in a sealing manner to the cylinder wall 1a of the cylindrical portion of the base 1. The space in contact with one surface of the piston 8 includes a through hole 9 provided in the cylindrical portion 8a of the piston 8, a through hole 10 provided in the peripheral wall of the cylindrical body 3, and a through hole provided in the outer cylindrical portion 4a. It communicates with the first fluid pressure feeding path 5 through a through hole 11 .

The space in contact with the other surface of the piston 8 is connected to the second surface through a through hole 12 provided in the cylindrical portion 8a of the piston 8 and a through hole 13 provided in the cylindrical body 3. It communicates with the fluid pressure feed path 6 of. The peripheral wall of the cylindrical portion 8a integrally formed with the piston 8 is sealed in ring-shaped guide holes 14 and 15 formed between the base 1 and the cylindrical body 3 and between the base cover 2 and the cylindrical body 3, respectively. They are fitted so that they can slide freely along the axial direction.

Reference numeral 16 denotes a disc-shaped operating plate made of a stainless steel plate or other elastic and strong thin metal plate, and a plurality of workpiece gripping claws 17 and 18 are integrally provided on this operating plate. A hole is formed in the center of the actuating plate 16, and a thick portion is formed near the hole. The central part of the actuating plate 16 is slidably fitted into the small diameter part 3a of the cylinder 3, and the thick part is connected to the cylinder part 8a of the piston 8 by means of screws 19 and 20.
is fixed to the end face of the

Reference numeral 19 denotes a mounting ring, and a fitting recess 19a is formed in the inner diameter portion of the mounting ring over the entire circumference. The diameter of the circumferential surface of the fitting recess 19a is set to be smaller than the outer diameter of the actuating plate 16. In this embodiment, the fitting recess 1
The diameter of the circumferential surface of 9a is 78 mm, and the outer diameter of the actuating plate 16 is set to 78.1 mm.

The outer peripheral end of the actuating plate 16 is press-fitted into the fitting recess 19a of the mounting ring 19, and in this state, the mounting ring 19 is fixed to the outer surface of the base cover 2 with bolts. . When the mounting ring 19 is fixed to the base cover 2, the fixing force of the mounting ring 19 to the base cover 2 causes the outer diameter portion of the actuating plate 16 to align with the surface 1 perpendicular to the axial direction of the mounting ring 19.
9b and the end surface of the tubular portion of the base cover 2, and the outer diameter portion of the actuating plate 16 is fixed to the end surface of the tubular portion 2a of the base cover 2 by this clamping pressure.

The actuating plate 16 is bent in either the left or right direction as shown in FIG. 3 by the pressure in the diameter reduction direction from the fitting recess 19a of the mounting ring 19, with the left and right bent state being in a stable state. In this embodiment, the amount of curvature is 0,
It is 7 mm. When the actuating plate 16 is bent to the left as shown by the solid line in FIG. 3 and is in a stable state, when pressure is applied to its center in the right direction, the actuating plate 16 will exhibit its own elasticity at the boundary point, that is, the flat plate shape, without being affected by external pressure. As a result, it curves sharply to the right as shown by the dotted line in Figure 3, and becomes stable. The same applies to the case where the stable state of rightward bending is changed to the stable state of leftward bending.

Next, the operation of this embodiment will be explained. In FIG. 2, when the actuation plate 16 is bent to the left, the workpiece gripping claws 17 and 18 are expanded, and when the actuation plate 16 is bent to the right, the workpiece gripping claws 17 and 18 are expanded.
18 will shrink. Expansion of the work gripping claws 17, 18,
Due to the reduction, the workpiece gripping claws 17 and 18 strongly grip or release the workpiece (not shown). When it is desired to bend the actuating plate 16 leftward from the state in which it is bent rightward in FIG. At the same time, air is removed from the space in contact with the left side surface of the piston 8, and the air pressure moves the piston 8 to the left in FIG.
Drive until it is locked.

As the piston 8 moves to the left, the central portion of the actuating plate 16, which is interlocked with the piston 8, is pushed leftward by the piston 8. When the actuating plate 16 reaches the flat plate shape shown in FIG. 1, that is, the neutral state in which it does not curve in either direction,
When pushed further to the left by the piston 8, the direction of curvature changes, and the actuating plate 16 bends to the left by its own elasticity as shown in FIG. 2. Therefore, the pressure of the air in the piston storage space may be of a magnitude that displaces the actuating plate 16 from its rightward bent state to a substantially neutral state, and the actuating plate 16 is bent leftward from its neutral state by: This is not the pressure of the air in the piston storage space, but the biasing force of the actuating plate 16 itself based on the diameter reduction pre-compression state of the actuating plate 16.

In order to bend the actuating plate 16 from the leftward bent state to the right direction in FIG. , the air in the air chamber in contact with the right side surface of the piston 8 is removed, and the piston 8 is driven by the air pressure in the right direction until it collides with the stopper surface 1b of the base 1. The actuating plate 16 is displaced by the rightward driving force from the piston 8 from the leftward bending stable state to the neutral state shown in FIG. The actuating plate 16 bends to the right due to its own elasticity and becomes stable.

[0020]

[Effects] Since the present invention is constructed as described above, there is an effect that the actuating plate can be driven with a small fluid pressure and that the workpiece can be strongly gripped.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing one preferred embodiment of the present invention.

FIG. 2 is an explanatory diagram of the present invention.

FIG. 3 is an explanatory diagram of the operation of the actuating plate.

[Explanation on code] 1 Base 1a Cylinder wall 2 Base cover 3 Cylindrical body 4 Fluid tube 5 Fluid pressure feed path 6 Fluid pressure feed path 7 Work stopper 8 Piston 8a Piston cylinder part 9 Through hole 10 Through hole 11 Through hole 12 Through hole 13 Through hole 14 Guide hole 15 Guide hole 16 Actuation plate 17 Work gripping claw 18 Work gripping claw 19 Mounting ring 19a Fitting recess

Claims (2)

[Claims] Claim 1: A base 1 that is detachably attached to a spindle of a machine tool or the like and has a cylinder wall 1a formed on its inner diameter.
a base cover 2 fixed to the base 1 and forming a fluid space between the base cover 2 and the base 1; a piston 8 slidably fitted to the cylinder wall 1a and disposed within the fluid space; A fluid tube 4 attached to the base 1 that pumps fluid to both sides of the piston 8, and a base cover whose outer diameter portion is precompressed in the diametrical direction and curved so as to have a stable state in two directions. 2. A chuck comprising: an actuating plate 16 which is fixed to the piston 2 and whose central portion is connected to the piston 8; and workpiece gripping claws 17, 18 provided on the actuating plate 16. 2. The chuck according to claim 1, wherein air is used as the pumping medium of the fluid tube 4, and the piston 8 is driven by the pressure of the air.