JPH0746410Y2 - Collet chuck device for lathe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a lathe collet chuck device incorporated in, for example, an ultra-precision lathe.

[Conventional technology]

Generally, parts used for OA equipment, optical parts, information equipment, etc. require ultra-precision due to the characteristics of the equipment itself, and when processing the parts, high accuracy is required even in the turning process. It is what is done. These parts are usually subjected to high-precision turning using an ultra-precision lathe.

Conventionally, as a work gripping device used for a lathe, as a general one, an actuator is provided at the rear end of the spindle,
There is a so-called power chuck, which holds a workpiece by opening and closing a chuck attached to a front end of a spindle via a draw bar provided in a through hole in the spindle.

When the rotation speed of the spindle required for turning the workpiece is high, a collet that is attached to the spindle and holds the workpiece may be used instead of the chuck.

Alternatively, especially for workpieces that require high precision,
A scroll chuck, which is an ultra-precision manual tightening method, is used.

[Problems to be solved by the device]

Although power chucks that are widely used are easy to obtain, they cannot hold workpieces with high precision, and are used for turning of parts used in OA equipment, optical parts, information equipment, etc. It cannot be used for high precision machining as required. On the other hand, in the case of the collet type gripping device, the rotation speed of the main shaft can be increased, but as a structural drawback of the collet itself, a radius that the collet can move when gripping a workpiece The amount of directional movement, i.e. the short radial stroke when clamping the workpiece, is raised. Therefore, each time the workpiece changes and the collet clamping diameter of the workpiece changes, a different collet must be replaced.

Moreover, the biggest problem with the chuck or collet is whether it is the power chuck method or the collet method.
An actuator, which is a power generation source for clamping and unclamping a workpiece, is attached to the rear end of the spindle from the viewpoint of space and structure, and a chuck or collet gripping device provided on the front end face of the spindle from the power generation source. In order to transmit the gripping force to the workpiece, it is done by the draw bar that passes through the through hole in the main shaft. For this reason, when the gripping device is operated, a compressive force by the draw bar acts on the main spindle, and if the main spindle cannot withstand the compressive force, buckling occurs on the main spindle, which results in machining of a workpiece. The accuracy will be adversely affected.

Therefore, in order to prevent buckling of the spindle, the spindle must be designed to have a rigidity that can withstand the compressive force. Therefore, a spindle that is larger than the size of the workpiece must be used. There is a problem that it must be. Also,
As the size of the main shaft increases, the inertial moment or vibration moment of the main shaft also increases, which is not preferable from the standpoint of starting, stopping, or balancing the rotation of the main shaft or rotating body.

On the other hand, although it is an ultra-precision hand-tightening type scroll chuck, although the above-mentioned buckling phenomenon does not occur, clamping or unclamping of the workpiece is a manual work and cannot be adopted in automation. Is.

The purpose of this invention is to solve the above-mentioned problems, and a double-acting cylinder is arranged at the front end of the spindle as a gripping force generation source for gripping a workpiece to bring it closer to the workpiece, and the response and gripping force. Of the collet system to obtain a high-speed spindle rotation speed required for turning a workpiece by eliminating the adverse effect of the gripping force on other parts, and to support automation. By adjusting the fluid pressure applied to the double-acting cylinder, the gripping force for grasping the work piece can be adjusted appropriately according to the work piece, and the headstock of the machine tool can be made smaller, resulting in the shape of the work piece. (EN) Provided is a collet chuck device for a lathe, which can easily carry out a corresponding setup change, that is, a work of replacing a collet, a claw, a reference gold and the like.

[Means for Solving the Problems]

The present invention is configured as follows to achieve the above object. That is, the invention is directed to a face plate fixed to the main shaft, a face plate boss portion fixed to a central hole formed in the face plate,
A fluid pressure can be supplied through a cylinder case attached to the face plate in an airtight state, a piston arranged in a hollow chamber formed by the cylinder case and the face plate boss portion, a fluid passage formed in the main shaft and the face plate boss portion. Chambers on both sides of the piston forming a double-acting cylinder, a piston rod exchangeably fixed to the piston rod portion of the piston, and an axial reciprocating movement of the piston rod exchangeably fixed to the cylinder case. Corresponding to the collet for displacing the end portion in the radial direction to clamp or release the workpiece, and a reference metal replaceably arranged between the workpiece and the face plate boss portion or the collet. Relates to a collet chuck device for a lathe.

Further, in this lathe collet chuck device, the collet has an elastically deformable portion, and a taper surface is formed on the tip side of the elastically deformable portion, and the taper surface formed on the piston rod contacts the taper surface. The collet is displaced in the radial direction by sliding.

[Action]

The collet chuck device for a lathe according to the present invention is configured as described above and operates as follows. That is, in this collet chuck device for lathes, a face plate is fixed to an end portion of a spindle, and a double acting cylinder is formed by a face plate boss portion fixed to a central hole formed in the face plate and a cylinder case. Since the fluid passage for supplying or discharging the fluid pressure to each chamber of the cylinder is formed in the main shaft and the face plate boss portion, the workpiece can be easily clamped or released by supplying the fluid pressure to the double-acting cylinder through the fluid passage. It is possible to arrange the double-acting cylinder as a gripping force generation source as close as possible to the workpiece, improve the response and the gripping force, and eliminate the adverse effect of the gripping force on other parts, and the workpiece. It is possible to obtain the high-speed spindle rotation speed required for the turning process.

Further, since the end portion of the collet is displaced in the radial direction in response to the axial reciprocal movement of the piston rod connected to the piston of the double-acting cylinder, it is possible to set a large amount of displacement of the collet in the radial direction. It can be adapted to work pieces of different diameters. In addition, just by adjusting the supply of fluid pressure to the double-acting cylinder, the collet,
Easy setup change such as replacement of nails, standard gold, etc.
Automation of the device itself can be facilitated.

〔Example〕

An embodiment of a collet chuck device for a lathe according to the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of a collet chuck device for a lathe according to the present invention. This collet chuck device for a lathe mainly forms a double-acting cylinder by a face plate 2 attached to a front end portion of a main shaft 1, a cylinder case 3 attached to the face plate 2 and a piston 4 which reciprocates in the cylinder case 3, By operating the double-acting cylinder, the piston rod 5 attached to the piston 4 reciprocates to displace the end portion of the collet 7 attached to the cylinder case 3 in the radial direction, and the workpiece 10 is clamped by the displacement in the radial direction. It is to release it.

This lathe collet chuck device is configured such that the outer peripheral surface of a workpiece 10 is externally gripped by a plurality of claws 8 provided on a collet 7. An annular face plate 2 is removably fixed to a front end portion (front end surface 19 in the figure) of a main shaft 1 of a lathe by bolts 28. In the center hole formed in the center of the face plate 2, a cylindrical face plate boss portion 21 extending in the axial direction is fixed in an airtight state by a bolt 29 via a sealing material such as an O-ring.

The face plate boss portion 21 has two fluid passages such as an air passage described later.
Outer pipe 24, central pipe 2 to form 15,16
3. The inner pipes 22 are concentrically arranged in an airtight state with a sealing material such as an O-ring interposed therebetween. The fluid passages 15 and 16 formed by these pipes extend through the main shaft 1 to the rear end portion of the main spindle 1, and the fluid passages 15 and 16 formed by the pipes are compressed by air pressure (or hydraulic pressure in some cases). Etc.) to communicate with a fluid pressure generation source such as a compressor (in some cases, a hydraulic pump) that generates fluid pressure, a fluid pressure supply port, and the like.

A cylinder case 3 having a central hole at the front end of the face plate 2
Bolts 30 in an airtight state with a sealing material such as an O-ring interposed.
Attached, and therefore the face plate 2, the face plate boss portion 2
1, cylinder case 3, and piston rod portion 6 described later
This forms an annular, airtight hollow chamber. In the figure, a bolt 28 integrally fixes the assembly of the face plate 2 and the cylinder case 3 to the spindle 1.

An annular piston 4 is arranged in the annular hollow chamber, and annular chambers 13 and 14 that are airtight to each other are formed on both sides of the piston 4, respectively. The piston 4 is provided with a cylindrical piston rod portion 6 as an integral structure. Moreover, the piston rod portion 6 has a seal material such as an O ring interposed between it and the cylinder case 3, and a seal material such as an O ring is interposed between the piston rod portion 6 and the cylinder plate 3 and the face plate boss portion. It projects from 21 to the outside.

Moreover, the piston 4 is a face plate boss portion fixed to the face plate 2.
A sealing material such as an O-ring is interposed between the outer peripheral surface of 21 and the inner peripheral surface of cylinder case 3 so as to be slidable in the axial direction in an airtight state, but relative to face plate 2 and cylinder case 3. A guide pin 20 is fitted in the face plate 2 and the piston 4 so as to prevent the proper rotation.

The guide pin 20 is provided with a fluid passage hole 38 communicating with the chamber 14 and the end face, and the pin hole provided in the tip end face of the guide pin 20 and the piston 4 is provided.
The bottom of 37 is configured to allow a fluid such as air to flow in to prevent sticking between the piston 4 and the guide pin 20 and to make the fluid pressure acting on the piston 4 uniform over the entire surface. The pressure is equalized to allow smooth reciprocating motion. Although not shown, it goes without saying that the guide pin may be fitted and provided in the cylinder case 3 and the piston 4.

These chambers 13 and 14 communicate with fluid passages 15 and 16 formed by the outer pipe 24, the central pipe 23, and the inner pipe 22 through fluid passages 17 and 18 formed in the face plate boss portion 21, respectively. The outer pipe 24, the central pipe 23, and the inner pipe 22 pass through the through holes of the main shaft 1 and supply or discharge operating pressure to / from each port from a rotary joint (not shown) fixed to the rear end of the main shaft 1. It is configured to be.

Further, the fluid passage 39 formed by the inner pipe 22 is
It may be used for a spare passage. For example, it can be used for supplying cutting oil to the turning portion during turning of the workpiece 10, or for blowing air for cleaning after turning of the workpiece 10. Further, a small cylinder is inserted into the fluid passage 39 and connected to the reference gold 9,
It may be used as an inspection hole for confirming the position setting of 10 and used as a passage for exhaust pressure for confirmation.

Therefore, the collet chuck device for the lathe is
A double-acting cylinder comprising a face plate boss portion 21, a cylinder case 3, and a piston 4 having a cylindrical piston rod portion 6,
To provide an actuator which is arranged at the front end of the spindle 1 and in which the double-acting cylinder is actuated by fluid pressure such as air pressure, and the double-acting cylinder is actuated to grip the workpiece 10. become.

A cylindrical piston rod portion 6 is formed integrally with the piston 4, and the piston rod portion 6 projects axially forward from the cylinder case 3. A cylindrical piston rod 5 having a flange portion 31 serving as a locking portion with the collet 7 at a tip end thereof can be attached to and detached from a threaded portion formed on the hollow inner peripheral surface of the piston rod portion 6, in other words, It is replaceably screwed and fixed.

The engaging portion formed on the piston rod 5 is composed of an annular groove 25 formed by undercutting a flange portion 31 provided at the end of the piston rod 5, and the outer surface of the annular groove 25 has a radial direction. The taper surface 11 is formed so as to be expanded.

A cylindrical collet 7 is replaceably attached to the front end surface of the cylinder case 3 by a bolt 32.
At the front end of the collet 7, a plurality of claws 8 (for example, three-point support in the case of three pieces, only one piece is shown in the figure) for holding the workpiece 10 are replaceably attached by bolts 34. ing. Further, the collet 7 is elastically deformable so that the collet 7 itself expands in the radial direction,
An elastically deformable portion 36 is formed by forming a slotted portion 35 at an intermediate portion. Further, an annular groove 26 cut in the circumferential direction is formed on the inner peripheral portion of the end of the collet 7, and a tapered surface 12 is formed on the inner side surface of the annular groove 26.

In the above structure, the tapered surface 12 formed on the collet 7 and the tapered surface 11 formed on the piston rod 5 are configured to be slidable in contact with each other by the axial movement of the piston rod 5. Therefore, the end of the collet 7 can be displaced from the slot 35 in the radial direction in response to the axial reciprocating motion of the piston rod 5.
Further, in order to set the workpiece 10 at a predetermined position, the reference gold 9 is detachably attached and screwed into the central hole 33 of the face plate boss portion 21 and fixed. The reference gold 9 can be replaced depending on the type of the workpiece 10 or the turning location of the workpiece 10, and the mounting location is not limited. In the figure, the workpiece 10 is set such that the tip surface 27 of the reference gold 9 is in contact with the surface of the workpiece 10.

Since this collet chuck device for lathe is configured as described above as an example, it can be operated as follows.

FIG. 1 shows a state in which the double-acting cylinder in this lathe collet chuck device is operated and the workpiece 10 is gripped by the claw 8. The state of gripping the workpiece 10 is achieved as follows. Compressor on lathe,
When a fluid such as air is supplied from a fluid pressure generation source such as compressed air supply means to the chamber 13 through the fluid passages 15 and 17, the piston 4 is guided by the guide pin 20 and moves to the face plate 2 side. The fluid present in chamber 14 is discharged through fluid passageways 18 and 16. Therefore, the piston rod 5 attached to the piston rod portion 6 of the piston 4 retracts.

When the piston rod 5 retracts, the outer peripheral portion of the flange 31 is fitted into the annular groove 26 formed in the collet 7, and the tapered surface 12 formed in the annular groove 26 of the collet 7 is formed in the annular groove 25 of the piston rod 5. Since the tapered surface 11 makes contact and slides, and the collet 7 is fixed to the cylinder case 3, it is displaced radially inward from the elastically deforming portion 36 of the collet 7, and the tip of the collet 7 is gradually reduced in diameter. To do. Therefore,
The plurality of claws 8 attached to the tip of the collet 7 move inward in the radial direction and contact the outer peripheral surface of the workpiece 10 to
You will be holding 10.

Conversely, releasing the workpiece 10 from the gripped state is accomplished as follows. Fluid such as air from a fluid pressure source such as a compressor in a lathe or compressed air supply means
When air is supplied to the chamber 14 through the fluid passages 16 and 18, the piston 4 moves to the side away from the face plate 2, and the fluid existing in the chamber 13 is discharged through the fluid passages 17 and 15. Therefore, the piston rod 5 fixed to the piston rod portion 6 of the piston 4 comes to project forward from the main shaft 1.

As shown by the dotted line in the figure, when the piston rod 5 advances, the outer peripheral portion of the flange portion 31 moves in a direction away from the annular groove 26 formed in the collet 7, and the tapered surface 12 formed in the annular groove 26 of the collet 7 Is the annular groove of the piston rod 5.
The taper surface 11 formed on 25 is slid in contact and advances forward, and since the collet 7 is fixed to the cylinder case 3, it is displaced outward in the radial direction from the elastically deforming portion 36 of the collet 7,
The tip of the collet 7 gradually expands. Therefore, the plurality of claws 8 attached to the tip end of the collet 7 move outward in the radial direction, move away from the outer peripheral surface of the workpiece 10, and the workpiece 10 is released.

Next, another embodiment of the collet chuck device for a lathe according to the present invention will be described with reference to FIG.

In the lathe collet chuck device shown in FIG. 2, the lathe collet chuck device described with reference to FIG.
While the outer peripheral surface of 10 is an external grip type with a plurality of claws 8 provided on the collet 7, a collet 47 is provided in the fitting hole 49 of the workpiece 40.
It is configured as an inner lining type in which is fitted and gripped by the expanding force. Regarding the difference in structure between the two embodiments, the collet chuck device for lathe shown in FIG.
Compared with the collet chuck device for a lathe described with reference to the drawings, the parts other than the piston rod 45 fixed to the piston rod portion 6 of the piston 4, the collet 47, and the reference gold 42 have the same configuration and function. Therefore, parts having the same configuration and function are designated by the same reference numerals, and overlapping description will be omitted.

To the piston rod portion 6 of the piston 4, a piston rod 45 having a locking portion 46 for engaging with a collet 47 is attached to the tip end portion so as to be attachable / detachable, that is, replaceable. Regarding the locking portion 46 formed on the piston rod 45, a taper surface 43 is formed on the outer peripheral surface of the flange portion provided at the end portion of the piston rod 45.

In addition, the front end surface of the cylinder case 3 has a cylindrical collet.
47 are replaceably attached by bolts 32.
A plurality of grips 41 for gripping the workpiece 10 are provided at the front end of the collet 47. Further, the collet 47 is provided with an elastically deforming portion 36 in which a slitting portion 35 is formed at an intermediate portion so that the collet 47 itself can be elastically deformed so as to expand in the radial direction. Further, a tapered surface 44 is formed on the inner peripheral surface of the end of the collet 47.

In the above configuration, the tapered surface 44 formed on the collet 47 and the tapered surface 43 formed on the piston rod 45 are configured to be capable of sliding contact with each other by the axial movement of the piston rod 45. Therefore, the end of the collet 47 corresponds to the axial reciprocating movement of the piston rod 45, and
It will be possible to displace radially from 35.

Furthermore, in order to set the workpiece 40 in place, the reference gold
42 is fixed to the cylinder case 3 by bolts 32 so as to be attachable and detachable. In the figure, the bolt 32 has a function of fixing the collet 47 and the reference gold 42 to the cylinder case 3 at the same time. The reference gold 42 can be replaced depending on the type of the work piece 40 or the turning location of the work piece 40, and the mounting location is not limited. In the figure, the workpiece 40 is set such that the surface of the workpiece 40 is in contact with the tip surface of the reference gold 42.

Next, since this lathe collet chuck device is configured as described above as an example, it can be operated as follows.

FIG. 2 shows a state in which the double-acting cylinder in this lathe collet chuck device is actuated and the outer peripheral surface 48 of the collet 47 is expanded to grip the workpiece 40. The state of gripping the workpiece 40 is achieved as follows. Since the forward / backward movement of the piston rod 45 is the same as the operation described with reference to FIG. 1, the description of the forward / backward movement of the piston rod 45 will be omitted.

When the piston rod 45 fixed to the piston rod portion 6 of the piston 4 extends forward, the taper surface 43 formed on the outer peripheral surface of the engagement portion 46 of the flange portion at the end portion of the piston rod 45 forms the inner peripheral surface of the collet 47. Since the collet 47 is fixed to the cylinder case 3 by sliding in contact with the tapered surface 44 formed in the above, the collet 47 is displaced outward in the radial direction from the elastically deforming portion 36 of the collet 47, and the tip of the collet 47 is gradually moved. Expand to.
Therefore, the tip of the collet 47 moves outward in the radial direction, and the engaging surface 48, which is the outer peripheral surface of the tip, abuts the fitting hole 49 of the workpiece 40, as shown by the solid line in FIG. To the workpiece
You will be gripping 40.

Conversely, releasing the work piece 40 from the gripped state is accomplished as follows. When the piston rod 45 fixed to the piston rod portion 6 of the piston 4 retracts toward the main shaft 1 side as shown by the dotted line in FIG. 2, the taper surface 43 of the outer peripheral surface of the flange portion 46 of the piston rod 45 becomes the collet 47. It moves away from the formed tapered surface 44, the tapered surface 43 of the piston rod 45 retracts away from the tapered surface 44 of the collet 47, and since the collet 47 is fixed to the cylinder case 3, the elasticity of the collet 47 is reduced. The collet 47 is displaced inward in the radial direction from the deformed portion 36, and the tip portion of the collet 47 is gradually reduced in diameter. Therefore, the engagement surface 48 provided at the tip of the collet 47 moves inward in the radial direction, away from the inner peripheral surface of the workpiece 40,
The workpiece 40 will be released.

Although the embodiment of the lathe collet chuck device according to the present invention has been described above, the lathe collet chuck device is not necessarily limited to the above embodiment. For example, the grasped portion of the workpiece is not limited to a circular shape, and may have any shape such as a polygonal shape or a curved shape. In addition, the collet, the claw, and the reference metal are mounted so that they can be replaced according to various conditions such as the shape and type of the workpiece. It is possible to use shapes, sizes, and special jigs that are suitable for circles, polygons, special shapes, and the like.

[Effect of device]

The collet chuck device for a lathe according to the present invention is configured as described above and has the following effects. That is, this collet chuck device for a lathe has a face plate fixed to the end of the main shaft, a cylinder case attached to the face plate in an airtight state and forming a hollow chamber between the face plate, the main shaft and the face plate boss portion. Chambers on both sides of the piston constituting a double-acting cylinder capable of supplying fluid pressure through the formed fluid passage, piston rods exchangeably fixed to piston rod portions of the pistons, exchangeably fixed to the cylinder case, and A collet for displacing the end of the piston rod in the radial direction corresponding to the axial reciprocating movement of the piston rod to clamp or release the workpiece, and replaceable between the workpiece and the face plate boss portion or the collet. Since it is composed of the reference gold arranged in the position, the double-acting cylinder or actuator, which is the power source for gripping the workpiece, is located at the position closest to the workpiece, that is, the actuator. It is possible to place it closer to the front end of the spindle, and the external force such as the compression force by the actuator and the mounting compression force does not act on the spindle itself, buckling phenomenon does not occur on the spindle, and the headstock and spindle of the lathe are small. Can be converted.

In particular, it is possible to improve the response of attachment / detachment of the workpiece and the gripping force, eliminate the adverse effect of the gripping force on other parts, and obtain the high-speed spindle rotation speed required for turning of the workpiece. It is possible to improve the processing accuracy of turning for a workpiece. Further, the workpiece can be easily gripped or released by supplying the fluid pressure to the actuator, that is, the double-acting cylinder, through the fluid passage.

In addition, simply by adjusting the supply of fluid pressure to the double-acting cylinder, a gripping force corresponding to the shape of the workpiece can be obtained, and moreover, setup changes such as collet, claw, and reference gold replacement work can be performed easily. , The automation of the device itself can be promoted.

[Brief description of drawings]

1 is a sectional view showing an embodiment of a lathe collet chuck device according to the present invention, and FIG. 2 is a sectional view showing another embodiment of a lathe collet chuck device according to the present invention. 1 ... Spindle, 2 ... Face plate, 3 ... Cylinder case, 4 ...
… Piston, 5,45 …… Piston rod, 7,47 …… Collet, 8 …… Claw, 9,42 …… Reference gold, 10,40 …… Workpiece, 11,
12,43,44 …… Tapered surface, 13,14 …… Room, 15,16,17,18…
… Fluid passage, 21 …… Face plate boss, 36 …… Elastic deformation.

Claims (2)

[Scope of utility model registration request] 1. A face plate fixed to a main shaft, a face plate boss portion fixed to a central hole formed in the face plate, a cylinder case airtightly attached to the face plate, and a cylinder case and the face plate boss portion. A piston arranged in a hollow chamber, chambers on both sides of the piston forming a double-acting cylinder capable of supplying a fluid pressure through a fluid passage formed in the main shaft and the face plate boss portion, and a piston rod portion of the piston can be replaced. A fixed piston rod, a collet that is replaceably fixed to the cylinder case, and has an end portion radially displaced corresponding to axial reciprocating movement of the piston rod to clamp or release a workpiece; and A collet chuck device for a lathe, comprising a reference metal that is replaceably arranged between a workpiece and the face plate boss portion or the collet. 2. The collet has an elastically deformable portion, and a taper surface is formed on the tip side of the elastically deformable portion,
The collet chuck device for a lathe according to claim 1, wherein the collet is displaced in the radial direction by the sliding contact of the tapered surface formed on the piston rod with the tapered surface.