JP2002254202A - Apparatus for holding rotating workpiece - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress a deflection phenomenon, a rope skipping phenomenon, and a chatter phenomenon by performing turning of a workpiece pulled by a tensile force. SOLUTION: A turning operation for the workpiece is performed by gripping the workpiece using a chuck attached to a rotating workpiece holding apparatus mounted on a tailstock spindle, and by applying a tensile force to the workpiece by turning a handle of a tailstock. By this constitution, the deflection phenomenon, rope skipping phenomenon, and chatter phenomenon of the workpiece can be suppressed. Therefore, an excellent turning operation can be preformed without using a steady rest and a follow rest.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to a method for turning a work with a lathe and an apparatus for holding the work by mounting it on a tailstock of the lathe. 2. Description of the Related Art Conventionally, when turning a bar or pipe work with a lathe, the work 11 is gripped by a chuck 3 and the other end surface of the work 11 is mounted on a tailstock shaft 6.
The workpiece 11 is rotated by the rotation of the main shaft 2 while being pressed and fixed at 0, and the turning is performed by the cutting tool 9. [0003] However, in the conventional turning, in the case of a work having a diameter smaller than the length of a work such as a bar or a pipe, the rotation center 4 mounted on the tailstock shaft 6 is used.
0 was pressed against the end face of the work 11 to fix the work 11 and perform turning. Deflection phenomenon of work due to pressing force,
Due to the centrifugal force due to the rotation and the cutting resistance of the blade, the work caused a jump rope phenomenon and a chatter phenomenon, and high-precision machining was not possible. If the length of the work exceeds about 10 times the diameter, a bending phenomenon, a jumping phenomenon, and a chattering phenomenon are likely to occur.
The fixed steady rest 41 is mounted between the rotary center 40 and the turning center 40 for turning, and the movable steady rest 41 which moves simultaneously with the blade 9 in the immediate vicinity of the blade 9 is mounted on the carriage 7 to improve the processing accuracy in the turning. I had it. However, the work efficiency at the time of machining has been remarkably reduced by mounting the fixed steady rest 41 and the movable steady rest 42. Also, many years of experience and skill were required to make full use of the steady rest and the like. [0006] The rotary work holding apparatus 20 of the present invention comprises a shaft 21 and a case 22, a radial bearing 23, a thrust bearing 24, and a bearing retainer 2.
5, a lid 26, a mechanism for preventing falling off, and the like. By inserting the thrust bearing 24 between the shaft 21 and the case 22, the work 11 can rotate freely even when a tensile force is applied to the work 11, which is a feature of the present invention. [0008] By inserting the radial bearing 23 between the shaft 21 and the case 22, the bending phenomenon and the centrifugal force applied to the work 11 can be suppressed. Turning can also be performed with a structure in which the radial bearing 23 is not inserted between the shaft 21 and the case 22. The falling of the rotary work holding device 20 caused by the pulling force at the tapered fitting portion 40 is performed by using a female screw formed on the end surface of the tightening ring 27 and the tailstock shaft 6 with a bolt 28.
To secure it to prevent it. By turning the above-described tightening ring 27, the distance between the end surface of the tailstock shaft 6 and the tightening ring 27 can be adjusted. The detachment of the rotary work holding device 20 caused by the pulling force at the tapered fitting portion 40 can be prevented by inserting the cotter pin 51 into the cotter hole formed in the tapered fitting portion 40 and lining the cotter pin 51. To remove the rotary work holding device 20 caused by the pulling force at the taper fitting portion 40, the screw rod 52 of the tailstock 5 is made hollow, and a pull screw 53 is inserted into the hollow portion. The pull screw 53 is inserted into the screw portion 29 of the rotating work holding device 20. This can be prevented by fixing with the lock nut 54. In the conventional turning process, the turning center 40 is applied to the end face of the work 11, the handle 10 of the tailstock 5 is turned, a pressing force is applied to the work 11, and the work is fixed and the turning process is performed. The present invention relates to a rotating work holding device 20.
The work 11 is gripped by the chuck 30 attached to the work, and the handle 10 of the tailstock 5 is turned to apply a tensile force to the work.
Turn. By turning the work by applying a tensile force to the work, which is a feature of the present invention, the bending phenomenon, the skipping phenomenon and the chatter phenomenon of the work are suppressed. Turning can also be performed by applying a tensile force to the work using air pressure or hydraulic pressure. By mounting the rotating work holding device of the present invention on a cylindrical grinder, it is possible to suppress the bending and chattering of the work during the grinding. By mounting the rotary work holding device of the present invention on a milling machine, it is possible to suppress the bending and chattering of the work during milling. EXAMPLE The work 11 is gripped by the chuck 3 of the lathe 1 and the length and diameter required for the chuck 30 to grip the tip are turned. The chuck 3 is loosened and the work 11 is pulled out by a length necessary for the turning process. The portion processed in the preceding paragraph is gripped by the chuck 30 mounted on the rotary work holding device 20, and then the work 11 is gripped by the chuck 3. Carry. After the tailstock 5 is fixed on the bed 12 of the lathe, the handle 10 of the tailstock 5 is turned to apply a tensile force to the work 11. When the main shaft 2 is driven to rotate, the work 11 rotates and is turned by the cutting tool 9. In the case of a rod-shaped work, the work 1 is
The female screw 1 is gripped and a female screw parallel to the center line of the spindle 2 and the tailstock 5 is formed in the center of the end face, and the male screw 35 is inserted into the female screw. After the male screw 35 is gripped by the chuck 30 mounted on the rotary work holding device, the handle 10 of the tailstock 5 is turned to perform turning work on the work 11 in the same manner as described above. In the case of a tubular work, the work 11 is gripped by the chuck 3, the other end is lined with the claws 31 of the chuck 30 mounted on the rotary work holding device 20, and the work 11 is gripped. Is turned to apply a tensile force to the work 11 to perform turning in the same manner as described above. In the grinding, when a bar-shaped or tubular workpiece is machined, if the workpiece is subjected to grinding by applying a tensile force to the workpiece with a chuck attached to a rotating workpiece holding device, the bending and chattering phenomena of the workpiece can be suppressed, and the precision can be reduced. Good processing is possible. In milling, when a rod-like or tubular workpiece is machined, a chuck attached to a rotating workpiece holding device applies a tensile force to the workpiece to suppress bending and chattering phenomena of the workpiece to be milled. Can be processed. [0027] Table 1 shows the results of pressing force turning and tensile force turning under the same working conditions as working example 1, material S45C, turning length 300mm, diameter 10mm. In machining example 2, small-diameter turning was performed by changing the axial load with an allowable value until the bulge at the center of the work increased by 0.03 mm from the diameter at both ends of the material S45C and the turning length was 50 mm. Table 2 shows the results. As described above, the bending phenomenon, the jump rope phenomenon, and the vibbling phenomenon can be suppressed by performing the turning process by applying the tensile force to the work. With the conventional method of fixing a workpiece by pressing at a rotating center, it was possible to accurately process an area where turning was difficult without using a steady rest or a movable steady rest. In addition, the present invention could be easily processed with relatively little experience because of the simple device.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing an entire lathe according to the present invention. FIG. 2 is a sectional view of a rotary work holding device. FIG. 3 is a drawing showing a state in which a male screw is inserted into an end face of a work and the work is gripped by a claw of a chuck. FIG. FIG. 4 is a drawing in which a tubular work is lined and held by a chuck. FIG. 5 is a sectional view showing a mechanism for preventing a tapered portion from dropping off. FIG. 6 is a side view showing the entire lathe with fixed steady rests and movable steady rests. [Description of Signs] 1 lathe 3 chuck 5 tailstock 7 carriage 8 turret 11 work 20 rotating work holding device 30 chuck 40 rotation center 41 fixed steady rest 42 moving steady rest

Claims (1)

Claims: 1. A method of turning a rod-shaped or tubular work with a lathe, wherein the other end of the work held by a spindle-side chuck is fixed by a rotation center or the like mounted on a tailstock. A rotating work holding device characterized by preventing a bending, a jumping rope, and a chattering phenomenon of a work, which occur at the time of turning. 2. The rotating work holding apparatus according to claim 1, wherein after the work is gripped by the chuck, a turning force is applied to the work by applying a tensile force to the work. 3. A rotary center for fixing a work by pressing an end face of the work with a conventional lathe.
Rotary work holding device. 4. The rotating work holding device according to claim 1, further comprising a tightening ring for preventing the tapered fitting portion from falling off due to a tensile force. 5. A tailstock having a hole for a cotter pin for preventing a tapered fitting portion from falling off caused by a tensile force, and a rotary work holding device according to claim 1. 5. A tailstock having a pull screw for preventing a taper fitting portion from falling off due to a tensile force, and a rotating work holding device according to claim 1. 7. A lathe having the features of claim 1 and claim 2 and all or one of claims 4 to 6. 8. A rotating work holding device having a feature that can be applied not only to turning but also to grinding and milling. 9. A grinding machine having the features of claim 1 and claim 2, and having all or one of claims 4 to 6. 10. It has the features of claim 1 and claim 2,
A milling machine provided with all or one of claims 4 to 6.