JPH08155772A - NC machine tool - Google Patents

Abstract

(57) [Summary] [Purpose] In an NC machine tool, the inner surface of a workpiece is positioned and gripped by chuck jaws, and the outer surface of the workpiece is cut with high precision without rechucking. [Structure] A chuck claw 3 is inserted into a center hole 5 of a workpiece 4 and the workpiece 4 is loosely gripped by the chuck claw 3. Next, the reference gold 25 is placed on the rear side of the workpiece 4. Next, the pressing device 32 is operated to press the workpiece 4 toward the reference surface 26 in the longitudinal direction of the reference metal 25, and then the chuck claw 3 is further opened to fix the workpiece 4 to the chuck body 1. Since the workpiece 4 is correctly positioned at the machining reference position, the front end surface 1 of the workpiece 4 can be simply chucked once.
8. The rear end surface 19 and the spherical surface 20 can be continuously turned at once.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an NC machine tool capable of positioning a workpiece at a machining reference position and gripping the workpiece on a chuck body.

[0002]

2. Description of the Related Art In NC machine tools, for example, NC
In the case of a lathe, the position and movement amount of the cutting edge of the cutting tool are programmed using a standard coordinate system fixed to the workpiece, and NC control is performed. Also, in order to save material waste, a work piece is used which has a size such that the cutting amount is as small as possible. Therefore, when mounting the workpiece on the NC machine tool, it is necessary to accurately position and mount the workpiece at a predetermined position.

In a conventional NC machine tool, the following processing method has been used to manufacture a product by cutting the surface of a workpiece having holes. For example, a case of manufacturing a ball for a ball stopcock will be described as an example. FIG. 4, FIG. 5, FIG. 6 and FIG. 7 are explanatory views showing the process of cutting the ball for the ball stopcock. FIG. 4 is a cross-sectional view showing a state where the workpiece 4 is gripped by the chuck claws 38a and 38b of the chuck body (not shown). The workpiece 4, which is a ball, is a spherical body made of synthetic resin, has a groove 39 on its surface, and has a center hole 5 formed therethrough at its center.

To finish the work 4, the work 4 is first moved to the position of the chuck body by an autoloader or the like. At this time, the chuck claws 38a and 38b are expanded. Therefore, the chuck claw 38a is fixed by an autoloader or the like.
And the work piece 4 between the two and 38b, as shown in FIG.
The chuck claws 38a, 38b are reduced in diameter to grip the workpiece 4 from the outside by the chuck claws 38a, 38b. That is,
The protrusion 40 provided on the chuck claw 38a fits into the concave groove 39 of the workpiece 4, and the other chuck claw 38b grips the spherical surface 20 of the workpiece 4. Workpiece 4 is chucked with chuck jaws 38a, 38
The inner diameter surface 43 of the center hole 5 of the workpiece 4 in the state of being gripped by b.
And the front end face 18 is cut (hereinafter referred to as the first step). In FIG. 5, in the first step, the center hole 5 is attached to the workpiece 4.
A state in which the inner diameter surface 43 and the front end surface 18 are subjected to cutting is shown.

Next, the workpiece 4 is turned by an autoloader or the like so that the front and rear of the workpiece 4 are reversed, and the central hole 5 of the workpiece 4 is inserted into the chuck claw 41 whose diameter is reduced.
Next, the longitudinal reference surface 4 formed on the chuck claw 41.
2 presses the front end face 18 of the workpiece 4 and then
As shown in, the chuck claw 41 is expanded in diameter to firmly fix the workpiece 4 to the chuck body. FIG. 6 shows a state in which the workpiece 4 is attached to the chuck body. Next, the rear end surface 19 and the spherical surface 20 of the workpiece 4 are cut (hereinafter referred to as the second step). Thus, through the first step and the second step, the workpiece 4 as shown in FIG.
As a finished product, a spherical ball that can be slidably rotated in the ball stopcock body will be manufactured.

[0006]

By the way, the ball for the ball stopcock needs only to be processed with high precision even on the outer surface if the function as a waterstop is simply considered, that is, with respect to the spherical accuracy of the outer shape. The surface roughness and the dimensional accuracy formed by the front end surface 18 and the rear end surface 19 may be taken into consideration.
It is not necessary to cut with high precision. That is, as a product, since the inner diameter surface 43 of the center hole 5 of the ball functions sufficiently even when the base material is left as it is, it is useless to cut the inner diameter surface 43. However, in the conventional ball cutting, there is a reason that the inner diameter surface 43 of the central hole 5 must be cut. That is, when the outer surface of the workpiece 4 is cut, it is impossible to grasp the outer surface of the workpiece 4 as shown in FIG. I have no choice but to hold it. Therefore, when the inner diameter surface 43 of the center hole 5 of the workpiece 4 is left as it is, the parallelism between the longitudinal reference surface 42 formed on the chuck claw 41 and the front end surface 18 of the workpiece 4 may be lost. ,
This will adversely affect the processing accuracy.

Further, in the conventional NC machine tool, the workpiece 4 has two steps, the first step performed in the gripping state shown in FIG. 4 and the second step performed in the gripping state shown in FIG. Is cut. Therefore, conventionally, chucking has been required twice, so that not only the machining accuracy is adversely affected by holding the workpiece, but also the machining efficiency is reduced. Moreover, two types of chuck claws are required.

[0008] Therefore, in order to solve these problems, even if the inner diameter surface of the workpiece is left as the base material, the inner diameter surface can be grasped by chuck claws and the workpiece can be accurately positioned. It is necessary to solve the problem of doing.

An object of the present invention is to solve the above problems of the conventional NC machine tool, to accurately and accurately position the workpiece on the chuck claw, and to grip the inner diameter surface of the workpiece with the chuck claw. Provided is an NC machine tool capable of continuously cutting the front end surface, the rear end surface and the spherical surface, which are the outer surface of the workpiece, with various cutting tools without re-chucking the workpiece with a chuck claw. That is.

[0010]

In order to achieve the above object, the present invention is configured as follows. That is, the present invention relates to a chuck main body having a chuck claw for gripping a workpiece and fixed to a main shaft, a tool rest movably arranged with respect to the chuck main body and capable of mounting various cutting tools, A base to which a table is attached and movable relative to the chuck body, a positioning setting device attached to the base, and insertable between the front surface of the chuck body and the workpiece mounted on the chuck body And a reference gold attached to the positioning setting device having a plane orthogonal to the rotation axis of the main shaft, and the base for pressing the workpiece on the chuck claw toward the reference plane in the longitudinal direction of the reference gold. And a pressing device attached to the NC machine tool.

Further, in this NC machine tool, in the pressing device, the pusher presses the workpiece toward the reference gold while buffering it by supplying compressed air, and returns to the original position by discharging compressed air. It is a thing.

Further, in this NC machine tool, a front end surface cutting tool, a rear end surface cutting tool, an outer part roughing tool and an outer part finishing tool can be attached to the respective tool rests. Has been done.

[0013]

The NC machine tool according to the present invention is constructed as described above and operates as follows. That is, according to this NC machine tool, the chuck claw provided on the chuck body is inserted into the hole formed in the workpiece, the chuck claw is slightly expanded in diameter, and the workpiece is loosely gripped. Then, the base on which the positioning setting device is placed is moved to place the reference gold on the rear side of the workpiece. Further, the pressing device is operated to press the workpiece toward the reference plane in the longitudinal direction of the reference metal, and in this state, the diameter of the chuck claw is further expanded to fix the workpiece to the chuck body. As a result, the workpiece is positioned at the machining reference position. Next, the positioning setting device is retracted from the workpiece, and the tool rest is moved closer to the chuck body. Since the positioning setting device is installed on the same base on which various tool rests are installed, it is all controlled by a series of programs incorporated in the NC device for cutting the workpiece. A device for independently controlling the operation of the positioning setting device is not required. Then, while rotating the main shaft to which the chuck body is attached, the workpiece can be gradually cut with various cutting tools attached to the tool rest. Since the workpiece is correctly positioned at the machining reference position and the inner diameter surface is gripped by the chuck claws, the workpiece only needs to be chucked once at a time without re-chucking the outer surface of the workpiece. It can be cut.

Since a front end surface cutting bite, a rear end surface cutting bite, a rough outer shape part cutting tool and a outer shape part finishing bite are respectively mounted on the base via the tool post, for example, for a ball stopcock. When cutting the workpiece such as the ball, first, the front end face of the workpiece is cut using the front end face cutting bite, and then the rear end face cutting bite is used. The rear end surface of the work piece is cut, then the outer surface of the work piece is roughly spherically cut by using the outer shape part rough cutting tool, and finally, the outer shape part finishing tool is used by the outer shape part finishing tool. By subjecting the outer surface to a spherical surface, the balls of the workpiece can be continuously and accurately turned.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENT An NC according to the present invention will now be described with reference to the drawings.
An embodiment of the machine tool will be described. 1 is a plan view showing a base on a tool rest side of an embodiment of an NC machine tool according to the present invention, FIG. 2 is a plan view showing a chuck body of an embodiment of the NC machine tool of FIG. 1, and FIG. FIG. 2 is a side view of the reference gold attached to the positioning setting device, as viewed from the direction of arrow A in FIG.

The chuck body 1 is attached to a spindle 2 rotatably provided on a headstock (not shown), and the chuck body 1 rotates together with the rotation of the spindle 2. The chuck body 1 has three chuck claws 3 on its front surface, and the workpiece 4 is gripped by the chuck claws 3. In the illustrated example, the work piece 4 is a spherical body formed of synthetic resin, and has a central hole 5 penetrating the center thereof. By cutting the workpiece 4, a ball for a ball stopcock is manufactured. The workpiece 4 is gripped by the chuck body 1 by inserting three chuck claws 3 into the center hole 5 and expanding the diameters of the chuck claws 3 so as to separate them from each other in the radial direction.

The base 6 is arranged so as to face the chuck body 1, and is arranged so as to be movable in the horizontal directions of the X axis and the Z axis. The base 6 is controlled by NC control on the horizontal plane in the direction of the rotation axis of the main shaft 2 (Z axis direction) and the rotation axis C
It is movable in a direction (X-axis direction) orthogonal to. On the upper surface of the base 6, there are two long grooves 7 having a T-shaped cross section (groove shape).
Are formed. The tool rest 8 has a slide holder 9 which is positioned and fixed at an appropriate position on the base 6. The slide holder 9 is configured to be slidable with respect to the long groove 7 and fixed on the base 6 by tightening a bolt 10. A shank holder 11 is fixed to the slide holder 9 by a bolt 13 via a pressing plate 12. Various cutting tools 14, 15, 16, 17 are fixed to the tip of the shank holder 11. In this embodiment, in FIG. 1, from the left, the outer shape part finishing tool 14,
A rear end surface cutting tool 15, a front end surface cutting tool 16 and an outer rough cutting tool 17 are provided.

In this NC machine tool, the front end surface cutting tool 16 is a tool for cutting the front end surface 18 of the workpiece 4, and the rear end surface cutting tool 15 is the rear end surface 19 of the workpiece 4.
It is a cutting tool for cutting,
Is a cutting tool for roughly cutting the spherical surface 20 of the workpiece 4, and the outer shape finishing tool 14 is a cutting tool for finishing the spherical surface 20 of the roughly cut workpiece 4. External finishing bit 1
For 4, a diamond cutter 21 having a semicircular tip is used.

The base 6 has a positioning setting device 2
2 are installed. The positioning setting device 22 has a slide holder 23 similar to the tool rest 8, the slide holder 23 is configured to be slidable with respect to the long groove 7, and is positioned at an appropriate position on the base 6 by tightening bolts. Fixed. A reference arm 24 is tightened and fixed to the slide holder 23 with a bolt 13 via a pressing plate 12. A reference gold 25 is attached to the tip of the reference arm 24. The reference gold 25 is attached to the tip end of the reference arm 24 with a bolt 27 so that the longitudinal reference surface 26 on the front surface thereof coincides with the plane orthogonal to the rotation axis C of the main shaft 2. The coordinates of NC control are set by the longitudinal reference plane 26 and the rotation axis C of the spindle 2. The reference gold 25 is U on one side of the rectangular plate.
The forked arm 28 is formed by cutting it into a letter shape. An inclined surface 30 is formed in a U-shaped portion on the back surface 29 of the reference gold 25.

By moving the base 6 in the X-axis direction and the Z-axis direction, that is, on the horizontal plane, the longitudinal reference metal 25 is provided between the front surface of the chuck body 1 and the work 4, that is, on the rear side of the work 4. It is possible to insert the reference gold 25 and arrange so that the chuck claw 3 is sandwiched by the forked arms 28. Further, the U-shaped inclined surface 30 is formed to avoid interference with the inclined surface 31 formed on the base of the chuck claw 3.

A pressing device 32 is attached near the positioning setting device 22. The pressing device 32 includes a pusher body 34 fixed to the slide holder 23 with a bolt 33.
And a pusher 35 attached to the tip of the pusher body 34. Pusher 35 is standard gold 25
Are located opposite to. Also, the pusher body 34
An air hose 36 is connected to the pusher 35, and the pusher 35 is pushed toward the reference metal 25 by supplying air, and is returned to the original position by the spring force of a spring (not shown) by removing the air. Pusher 35
Is absorbed by the spring force of the spring 37 when it is pressed against the workpiece 4, so that no unreasonable force is applied to the workpiece 4.

Positioning setting device 22 and various bytes 14,
The reference numerals 25, 16 and 17 are fixed to the base 6 so that they can move integrally on a horizontal plane.
When placed between and, the bytes 14, 15, 1
It is not possible to cut the work piece 4 with 6,17. In order to cut the workpiece 4, the base 6 is moved to move the reference gold 2
After completely retracting 5 from work 4,
It is necessary to bring 15, 16, 17 close to the workpiece 4.

Next, the operation of this NC machine tool will be described. When cutting the workpiece 4 with an NC machine tool, the workpiece 4 is first attached to the chuck body 1. The attachment operation of the workpiece 4 to the chuck body 1 will be described.

By operating an autoloader (not shown), for example, a grasping claw (not shown) of the autoloader is inserted into the center hole 5 of the workpiece 4 molded of synthetic resin to grasp one end of the workpiece 4. Therefore, the autoloader moves right above the spindle rotation axis C while keeping the axis of the center hole 5 of the workpiece 4 and the spindle rotation axis C parallel to each other. Next, the autoloader descends and stops when it descends to a position where the main shaft rotation axis C and the center hole axis substantially match. On the other hand, the chuck body 1 has 3
The individual chuck claws 3 are on standby in a state in which they are brought close to each other and have their diameters reduced. Then, the once stopped autoloader then advances in the Z-axis direction toward the chuck body 1 on the spindle 2 side, and the reduced diameter chuck jaws 3 are inserted into the center hole 5 of the workpiece 4. The advancing of the work piece 4 stops almost at the gripping position.

Next, the diameter of the chuck claws 3 is expanded, and the workpiece 4 is loosely gripped by each chuck claw 3. As a result, the workpiece 4 is temporarily fixed by each chuck claw 3 of the chuck body 1. The autoloader removes the gripped workpiece 4, retracts from the spindle 2 side in the Z-axis direction, then ascends, moves above the spindle rotation axis C, and waits.

Next, the base 6 to which the positioning setting device 22 is attached advances in the Z-axis direction toward the workpiece 4 temporarily fixed to the chuck claw 3 on the spindle 2 side, and then advances in the X-axis direction. Thus, as shown by the chain line in FIG. 2, the reference gold 25 is inserted between the front surface of the chuck body 1 and the workpiece 4 temporarily fixed to the chuck claw 3. Next, the standard gold 2
5 approaches the rear end surface 19 of the workpiece 4 and slightly retracts in the Z-axis direction to stop. This position becomes the machining reference position in the longitudinal direction with respect to the workpiece 4. Then, the pusher 35 of the pressing device 32 arranged so as to face the reference gold 25 advances,
The workpiece 4 is pressed from the front end surface 18 side to press the rear end surface 19 of the workpiece 4 against the longitudinal reference surface 26 of the reference metal 25. Therefore, the chuck claw 3 that was loosely gripping the workpiece 4 is further expanded in diameter to be in a regular gripping state of the workpiece 4, and
Is positioned and firmly fixed to the chuck claw 3. Then, the compressed air is discharged from the pusher 35, and the pusher 35 retracts and returns to the base 6 side by the return spring, and the reference gold 25 retracts from the workpiece 4 following the above movement. As a result, the workpiece 4 is correctly set to the machining reference position with respect to the chuck body 1.

By the above operation, the attachment of the workpiece 4 to the chuck body 1 is completed, and then the cutting process for the workpiece 4 is started. The cutting process for the workpiece 4 will be described later. When the cutting of the workpiece 4 is completed, the workpiece 4 is removed from the chuck body 1. The operation of removing the workpiece 4 from the chuck body 1 will be described below.

First, the autoloader advances right above the main shaft rotation axis C. After confirming that the base 6 has retracted outside the operating area of the autoloader,
When the center axis of the gripping claws of the autoloader almost coincides with the main shaft rotation axis C by descending from directly above, the descent of the autoloader is stopped. Next, the autoloader advances in the Z-axis direction toward the workpiece 4 on the spindle 2 side, and the gripping claws of the autoloader are inserted into the center hole 5 of the workpiece 4. The gripping claw of the autoloader expands and grips the workpiece 4. Therefore, the diameter of the chuck claw 3 provided on the chuck body 1 is reduced to loosen the grip of the workpiece 4. While holding the workpiece 4, the autoloader moves backward from the workpiece 4 on the spindle 2 in the Z-axis direction and rises right above the spindle rotation axis C. Next, the autoloader moves to a predetermined position, and the ball-shaped workpiece 4 that has been subjected to the cutting process.
Are recovered. Then, the autoloader grips the workpiece 4 to be processed next, and the above cutting process is repeated.

Next, the process of cutting the workpiece 4 into balls for a ball stopcock will be described. While rotating the workpiece 4, the NC controller moves the base 6 in the X-axis direction and the Z-axis direction, and the cutting tool is pressed against the workpiece 4 for cutting. First, the front end surface cutting tool 16 is used to machine the front end surface 18 of the workpiece 4, and then the rear end surface cutting tool 15 is used to machine the rear end surface 19 of the workpiece 4, and then A ball is manufactured by roughly cutting the spherical surface 20 of the workpiece 4 by using the outer shape roughing tool 17, and finally by finishing the outer surface of the workpiece 4 on the spherical surface 20 by using the outer shape finishing tool 14. be able to.

[0030]

Since the NC machine tool according to the present invention is constructed as described above, it has the following effects. That is, according to this NC machine tool, the chuck claw provided on the chuck body is inserted into the center hole of the workpiece, the diameter of the chuck claw is expanded, and the workpiece is gripped by the chuck claw. The base to which the positioning setting device is attached is moved relative to the chuck body, and the reference gold attached to the positioning setting device is inserted between the front surface of the chuck body and the workpiece. When the pressing device is actuated to press the workpiece toward the reference plane in the longitudinal direction of the reference gold, the rear side of the workpiece is pressed against the front surface of the reference gold, and the workpiece is installed at the machining reference position. To be done.

Therefore, even if the inner diameter surface of the center hole of the workpiece is not accurately machined or is not machined at all, the workpiece is simply chucked once by the chuck claws to perform the machining. The workpiece is placed at the processing reference position in a state where the surface to be cut is cut by the cutting tool, and there is no need to change the workpiece with the chuck claws. The surface can be continuously and gradually cut.
Therefore, in this NC machine tool, it is not necessary to re-chuck the work piece as in the conventional case, and it is not necessary to cut the inner diameter surface of the center hole of the work piece. Since only one chucking is required, it is possible to significantly improve the cutting accuracy for the workpiece and significantly improve the efficiency of cutting the workpiece.

Further, since this NC machine tool can perform continuous cutting of the outer surface of the workpiece all at once by simply gripping the inner diameter surface of the workpiece, there are two types of chuck claws as in the conventional case. Need not be prepared, and only one type of chuck claw is required. Since the positioning setting device for the workpiece and the tool rest to which the cutting tool is attached are mounted on the same base, the positional relationship between the reference gold and the cutting tool does not change, and the workpiece The processing accuracy can be improved.

Further, since the positioning setting device and various kinds of the cutting tool are fixed to the base, and the two are integrally movable on a horizontal plane,
When the reference gold is arranged between the front surface of the chuck body and the workpiece, the cutting tool cannot cut the workpiece. To cut the work piece, the base must be moved to completely retract the reference gold from the work piece before the bite is brought closer to the work piece. Therefore, it is possible to avoid a situation where the bite and the reference gold interfere with each other and the reference gold is damaged.

[Brief description of drawings]

FIG. 1 is a plan view showing a tool post side of an embodiment of an NC machine tool according to the present invention.

2 is a plan view showing a chuck body of an embodiment of the NC machine tool of FIG. 1. FIG.

FIG. 3 is a side view of the reference gold attached to the positioning setting device, as viewed from the direction of arrow A in FIG.

FIG. 4 is a cross-sectional view showing a state in which a workpiece is gripped by a chuck claw of a chuck body in a conventional NC machine tool.

5 is a cross-sectional view of the workpiece when the center hole and the front end face are cut in the gripping state shown in FIG.

FIG. 6 is a cross-sectional view showing a state when the workpiece shown in FIG. 5 is changed in direction and gripped by the chuck claws of the chuck body.

FIG. 7 is a cross-sectional view of a ball as a finished product in which the rear end surface and the outer surface of the workpiece are cut in the gripping state shown in FIG. 6;

[Explanation of symbols]

 1 Chuck Main Body 2 Spindle 3 Chuck Claw 4 Workpiece 6 Base 8 Turret 14 14 External Finishing Bit 15 Rear End Cutting Bit 16 Front End Cutting Bit 17 External Roughing Bit 22 Positioning Setting Device 25 Reference Gold 26 Longitudinal Reference Surface 32 Pressing device 35 pusher

Claims (3)

[Claims] 1. A chuck main body having a chuck claw for gripping a workpiece and fixed to a main shaft, a tool rest movably arranged with respect to the chuck main body and to which various cutting tools can be attached, respectively. A base to which is attached and is movable relative to the chuck body,
Positioning setting device attached to the base, the positioning setting device having a plane insertable between the front surface of the chuck body and the workpiece mounted on the chuck body and having a plane orthogonal to the rotation axis of the spindle. And a pressing device attached to the base for pressing the workpiece on the chuck jaws toward the reference plane in the longitudinal direction of the reference metal.
C machine tool. 2. The pressing device is characterized in that a pusher presses the workpiece toward the reference gold while buffering the work by supplying compressed air, and returns to the original position by discharging the compressed air. The NC machine tool according to Item 1. 3. A front end surface cutting tool, a rear end surface cutting tool, an outer part roughing tool and an outer part finishing tool can be attached to each of the turrets, respectively. The NC according to claim 1.
Machine Tools.