JPH06126589A - Spindle of machine tool and its rotational balance regulating method - Google Patents

Abstract

PURPOSE:To regulate the balance of the central part of a main spindle to facili tate the regulation of unbalance occurring at the central part of the spindle at the time of high speed revolution by inserting a balance regulating member into the axial center part of the spindle of a machine tool. CONSTITUTION:A plurality of balance regulating screw holes 1a, 9a are formed at the tip of a main spindle 1 and a nut 9. In addition, a balance regulating ring 10 is attached to a draw bar 7 located between coned disc springs 6. Next after the spindle 1 is assembled in a spindle head 3, a weight regulated in its weight is prepared so as to be inserted into the screw hols 1a, 9a, and after the rotational balance at the central part is previously regulated under a condition where the other parts are assembled on the spindle 1, the rotational balance of the whole of the spindle is regulated. Thus the vibration of the main spindle at the time of high speed revolution can be reduced.

Description

Detailed Description of the Invention

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle of a machine tool and a rotation balance adjusting method thereof, and particularly to a spindle which is rotated at a high speed, and a spindle of a machine tool suitable for adjusting the rotation balance and the rotation balance thereof. It relates to the adjustment method.

2. Description of the Related Art A spindle head of a machine tool such as a machining center is constructed as shown in FIG. Spindle 1 is
It is rotatably supported by the housing 3 via the rolling bearing 2. The stator 4 that constitutes the motor is fixed to the housing 3, and the rotor 5 is fixed to the main shaft 1. The disc spring 6 is attached to the draw bar 7 and inserted into the main shaft 1. A drawbar 8 is attached to one end of the drawbar 7, and a nut 9 is screwed onto the drawbar 7. The rotational balance of the spindle 1 is adjusted in the state of the spindle 1 alone before the spindle head is assembled. To adjust the rotation balance of the spindle 1, the spindle 1 is placed on a balancing device, and while measuring the rotation balance of the spindle 1, as shown in FIG. 5, a hole 1b is bored or ground at a required position of the spindle 1. While adjusting.

In such an adjusting method, in adjusting the rotation balance of the main spindle alone, the rotation balance of the main spindle can be adjusted with high accuracy, but unbalance of other parts incorporated in the main spindle can be prevented. Since it cannot be adjusted, the vibration of the spindle becomes large in the high-speed rotation region exceeding 10,000 revolutions per minute due to the imbalance of other components incorporated in the spindle. Especially, in the case of a spindle whose length is longer than its diameter, vibrations due to imbalance in the central part of the spindle appear at both ends, so even if the spindle is balanced alone, large vibrations appear at both ends of the spindle during high-speed rotation. There was a phenomenon. In view of the above circumstances, an object of the present invention is to provide a method for adjusting the rotational balance of the spindle of a machine tool that enables high-speed rotation.

In order to achieve the above object, in the present invention, a balance adjusting member is inserted into the axial center portion of the main shaft of the machine tool. Also, after forming a plurality of screw holes at both ends of the main shaft and incorporating a drawbar, disc spring, and motor rotor, attach a test weight to the main shaft and rotate it to measure the rotation angle and vibration amplitude of the main shaft. Based on the measurement results, after adjusting the balance of the central portion of the spindle in the axial direction, the spindle is rotated again, the rotation angle and vibration amplitude of the spindle are measured, and based on this measurement result, the weight of the screw hole is Insert the adjusted screw.

With the balance adjusting member, the rotation balance of the central portion of the spindle is adjusted to facilitate the adjustment of the rotation balance of the entire spindle. In addition, screw holes are formed at both ends of the main shaft, and a weight whose weight is adjusted is inserted into these screw holes. By adjusting the rotation balance of the entire main spindle after adjusting the above, it is possible to provide a spindle with high precision balance adjustment and high-speed rotation.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 and 2, the same elements as those in FIG. 4 are denoted by the same reference numerals. A plurality of screw holes 1a for balance adjustment are formed at a predetermined interval at the tip of the main shaft 1. On the end surface of the nut 9, a plurality of screw holes 9a for balance adjustment are formed at predetermined intervals.
The drawbar 7 has a pair of grooves 7 from the rear end to the center.
a is formed. Reference numeral 10 is a balance adjusting ring, which has screw holes 10a formed therein and is attached to the draw bar 7 so as to be positioned between the disc springs 6. 11 is a screw,
The ring 10 is screwed into a screw hole 10a formed in the ring 10, and one end thereof is movably inserted into the groove 7a. A vibration pickup 12 is attached to both ends of the spindle head 3. 13 is a rotation detector equipped with a light emitting element and a light receiving element,
It is attached to the spindle head 3 so as to face one end of the spindle 1. With such a configuration, after incorporating the spindle 1 into the spindle head 3 as shown in the figure, the alignment mark is attached to the spindle 1 and the draw bar 7 with quick-drying ink or the like. In this state, the spindle 1 is rotated. Then, the vibration pickup 12 outputs the vibration of the main shaft 1 due to the rotation. On the other hand, the rotation detector 1
From 3, a pulse signal is output for each revolution of the main shaft 1. Therefore, by superimposing the output of the rotation detector 13 and the output of the vibration pickup 12, it is possible to measure the unbalanced phase and the vibration amount of the spindle 1. Next, a test weight whose weight is known is attached to an arbitrary position of the screw hole 1a for balance adjustment, the main shaft 1 is rotated, and the vibration of the main shaft 1 is measured as described above. ◆ Screw hole 1 for balance adjustment
Remove the trial weight of “a” and attach the trial weight to the screw hole 9a to attach the spindle 1
Is rotated and the vibration of the main shaft 1 is measured in the same manner as described above. The imbalance amount in the central portion of the spindle 1 is estimated based on the above-mentioned three measurements. Then, the drawbar 7 is taken out from the main spindle 1, the part 10b of the ring 10 is ground, and the balance of the central portion of the main spindle 1 after assembly is adjusted. Again, after aligning the alignment marks and assembling the spindle 1, the spindle 1 is rotated,
Measure vibration. ◆ Next, balance adjustment screw hole 1
A test weight whose weight is known is attached to an arbitrary position of a to rotate the spindle 1, and the vibration of the spindle 1 is measured in the same manner as described above. ◆ Remove the trial weight of the screw hole 1a for balance adjustment, attach the trial weight to the screw hole 9a, rotate the spindle 1, and measure the vibration of the spindle 1 in the same manner as described above. Then, based on these measurement results, the unbalance amount and phase of the spindle 1 are determined, and the weights whose weights have been adjusted in advance are placed in the screw holes 1a and 9a. By dividing the rotation speed of the main spindle 1 into several stages from low speed rotation to high speed rotation and repeating the above adjustment work, as shown in FIG. 3, the rotation balance of the main spindle 1 can be adjusted with high accuracy, It is possible to provide the spindle 1 that can rotate at high speed. The balance adjustment of the central portion of the main shaft 1 may be performed only once.

As described above, according to the present invention, since the balance adjusting member is inserted in the shaft center portion of the spindle of the machine tool, the balance of the central portion of the spindle can be adjusted, and the central portion of the spindle generated at high speed rotation can be adjusted. The unbalance of the parts can be adjusted. Also, after forming a plurality of screw holes at both ends of the main shaft and incorporating a drawbar, disc spring, and motor rotor, attach a test weight to the main shaft and rotate it to measure the rotation angle and vibration amplitude of the main shaft. After adjusting the balance of the axial center of the spindle based on the measurement results, rotate the spindle again, measure the rotation angle and vibration amplitude of the spindle, and adjust the weight of the screw hole based on the results. By virtue of the inserted weight, it is possible to reduce vibration of the spindle during high-speed rotation, and it is possible to provide a spindle capable of high-speed rotation.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an assembled state of a spindle of a machine tool according to the present invention.

FIG. 2 is a perspective view showing an assembled state of a draw bar, a disc spring and a ring in FIG.

FIG. 3 is a characteristic diagram showing a balance adjustment result according to the present invention.

FIG. 4 is a side sectional view showing an assembled state of a spindle of a conventional machine tool.

FIG. 5 is a perspective view showing a balance adjusting method for a single spindle.

[Explanation of symbols]

 1 Spindle 1a, 9a Screw hole 5 Motor rotor 6 Disc spring 7 Drawbar 10 Ring

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Tanaka 2100 Kamiimaizumi, Ebina City, Kanagawa Prefecture Hitachi Seiko Co., Ltd.

Claims (2)

[Claims] 1. A spindle of a machine tool, wherein a balance adjusting member is inserted between the shaft center portions of the spindle of the machine tool. 2. A main shaft is provided with a plurality of screw holes at both ends thereof, a draw bar, a disc spring and a motor rotor are incorporated therein, and a test weight is attached to the main shaft to rotate the main shaft to measure a rotation angle and a vibration amplitude of the main shaft. Then, based on this measurement result, after adjusting the balance of the central portion of the spindle in the axial direction, the spindle is rotated again, and the rotation angle and vibration amplitude of the spindle are measured. A rotation balance adjusting method for a spindle of a machine tool, characterized in that a weight having an adjusted height is inserted.