JP2002292534A - Spindle unit and method for centering the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily achieve required concentricity between a front bearing and a rear bearing. SOLUTION: In a process for assembling a spindle head, a front bearing housing 13 is fitted and fixed into a bore at a front end of a spindle head body 12, a rear bearing housing 18 is temporarily assembled on a mounting plate 17, and a main spindle 11 is assembled into a front bearing 16 and a rear bearing 19. And then, a displacement gauge 20 is fixed to a rear end of the main spindle 11 and run-out of an inner surface (a surface for mounting a bearing) of the rear bearing housing 18 is measured using the displacement gauge 20. And then, the mounting position of the rear bearing housing 18 is adjusted by adjusting four adjust bolts 22 (upper, lower, right, and left) so as to minimize the measured run-out. After that, the rear bearing housing 18 is firmly fixed to the mounting plate 17. By such a procedure, required concentricity between the front bearing 14 and the rear bearing 19 can easily be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spindle unit having first and second bearings respectively attached to a front end and a rear end of a head main body and rotatably supporting both ends of a spindle. The present invention relates to a spindle unit for aligning the axis with first and second bearings and a method for centering the spindle unit.

[0002]

2. Description of the Related Art Conventionally, a spindle unit of a machine tool is provided with a front bearing box and a rear bearing box each having a bearing for rotatably supporting the spindle. The front bearing box is fitted and fixed in a hole at the front end of the head body, and the rear bearing box is fitted and fixed in a hole at the rear end of the head body. By specifying the concentricity of the inner peripheral surface, which is the bearing mounting surface of the front bearing housing, and the inner peripheral surface, which is the bearing mounting surface of the rear bearing housing, the concentricity of the front bearing and the rear bearing is the same. Had a core.

[0003]

However, in the conventional spindle unit, when a machining error occurs in actual machining, the front bearing box and the rear bearing box are fitted into holes at the front end and the rear end of the head body, respectively. Since the bearings are attached and fixed, the processing errors of the two bearing boxes are added together, and the concentricity of the front bearing and the rear bearing is lost in practice. Also, assembling the spindle unit in this state has been one of the causes of vibration of the spindle. Further, since there is no mechanism for adjusting and aligning the axes of the front bearing and the rear bearing, it has been troublesome and costly to disassemble and rework the spindle unit once.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a spindle unit and a centering method for easily aligning the concentricity of a front bearing and a rear bearing.

[0005]

In order to achieve the above object, the present invention has first and second bearings respectively attached to a front end and a rear end of a head body and rotatably supporting both ends of a main shaft. In the spindle unit, a first bearing box fitted and fixed in a hole at a front end of the head body, and attached to the first bearing, and attached to a rear end face of the head body perpendicular to the spindle. A second bearing box to which the second bearing is mounted; and an adjusting mechanism for adjusting a mounting position of the second bearing box in the rear end face.

[0006] With this configuration, the first bearing housing and the main shaft are assembled to the head body, and
Temporarily assembling the second bearing box on the rear end face of the head body, attaching a measuring means to the rear end of the main shaft, rotating the main shaft, and mounting the second bearing on the second bearing box. By measuring the amount of runout of the bearing mounting surface, based on the measurement result, by using the adjustment mechanism to adjust the mounting position of the second bearing box in the rear end surface so as to minimize the amount of runout. Concentricity of the front bearing and the rear bearing can be easily obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view showing an embodiment of a spindle unit of the present invention, and FIG. 2 is a right side view of FIG. Reference numeral 12 denotes a head body, and a front bearing box 13 as a first bearing box is fitted and fixed to an inner peripheral surface of a hole 12A at a front end of the head body 12. On the inner peripheral surface of the front bearing box 13, two front bearings 16, 16 are fitted as first bearings that rotatably support the main shaft 11. In addition, 14 is an inner ring spacer, and 15 is an outer ring spacer.

An attachment plate 17 is attached to the rear end of the head body 12 by bolts or the like. A rear end face 17A of the mounting plate 17 is formed in a plane perpendicular to the main shaft 11, and the rear end face 17A has a rear bearing box 1 as a second bearing box.
8 are attached. A rear bearing 19 as a second bearing is fitted on the inner peripheral surface (bearing mounting surface) of the rear bearing box 18.

An adjusting means comprising an adjusting bolt 21 and a block 22 is attached to the rear end of the mounting plate 17 so as to correspond to the outer periphery of the rear bearing box 18, and four positions of upper, lower, left and right. By adjusting the position of 21, the position of the rear bearing box 18 is adjusted.

A rotor 23, which is a rotating portion of the motor, is fixed to the outer periphery of the central portion of the main shaft 11, and a columnar stator 24 having a coil is provided on the head body 12, and the rotor 23 and the stator 24 Spindle 11
Is designed to rotate.

Next, a centering method using the present apparatus will be described. In the spindle head assembling process, the front bearing box 13 is fitted and fixed to the inner peripheral surface of the front end of the head body 12, and the rear bearing box 1 is fixed.
8 is temporarily assembled to the mounting plate 17, and the main shaft 11 is assembled to the front bearing 16 and the rear bearing 19. Thereafter, a displacement gauge 20 as a measuring means such as a small dial gauge is attached to the main shaft 11.
The main shaft 11 is manually rotated by an operator after being attached to the rear end, and the displacement of the inner peripheral surface (bearing mounting surface) of the rear bearing box 18 is measured by the displacement meter 20. By measuring the amount of the shake, it is possible to measure in which direction of up, down, left, and right the misalignment has occurred. The mounting position of the rear bearing box 18 is adjusted by adjusting the upper, lower, left, and right adjustment bolts 22 so as to minimize the runout. By doing so, the concentricity of the front bearing 16 and the rear bearing 19 is provided, and the rear bearing box 18 is fixed to the mounting plate 17.

[0012]

As described above, the spindle unit and the centering method of the present invention can easily align the front bearing and the rear bearing with each other. The precision machining step of the fitting portion with the main body can be omitted, and the number of assembling steps in assembling the spindle unit can be reduced. With the main shaft assembled in this way, the front and rear bearings are concentric, so that no excessive force is applied to the main shaft itself, and the bearing life is prolonged due to low vibration and low heat generation. Can be.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a spindle unit of the present invention.

FIG. 2 is a right side view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Main shaft 12 Head main body 13 Front bearing box 14 Inner ring spacer 15 Outer ring spacer 16 Front bearing 17 Mounting plate 18 Rear bearing box 19 Rear bearing 20 Displacement gauge 21 Adjustment bolt 22 Block 23 Rotor 24 Stator

Continued on the front page F term (reference) 3C029 AA02 3C030 CA01 3C045 FD12 3C048 BB16 BB20 BC04 CC04 DD11 EE10

Claims (2)

[Claims] 1. A spindle unit having first and second bearings respectively attached to a front end and a rear end of a head main body and rotatably supporting both ends of the main shaft, wherein the main unit is fitted and fixed in a hole at a front end of the head main body. A first bearing box to which the first bearing is attached; a second bearing box to which the second bearing is attached, which is attached to a rear end face of the head main body perpendicular to the main shaft; An adjusting mechanism for adjusting a mounting position of the second bearing housing in the rear end surface thereof. 2. The centering method of the first and second bearings of the spindle unit according to claim 1, wherein the first bearing housing and the spindle are assembled to the head main body, and Temporarily mounting the bearing box on the rear end surface of the head main body, and attaching a measuring means to the rear end of the main shaft, rotating the main shaft, and mounting the second bearing on the second bearing box. Measuring the amount of runout of the bearing mounting surface, and adjusting the mounting position of the second bearing box in the rear end surface using the adjusting mechanism so as to minimize the amount of runout based on the measurement result. A method of centering a spindle unit, comprising: