JP2004036864A - Spindle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spindle that can set practical machining depth to 3mm or more even in a drill with a diameter of 0.1mm, for instance. <P>SOLUTION: The length M in the direction of an axis O of a portion for enclosing a flange part 21 of a hole 24 for enclosing a rotor 21 is made longer than the sum of the thickness and moving distance L of the flange part 21b. The pressure of a fluid supplied to fluid bearings 27, 28 arranged on both sides of the flange part 21b is changed by a control device 52 to position the rotor 21 in an optional position in the direction of the axis O of rotation in a range of the distance L. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a spindle that supports a rotor holding a tool in a radial direction (radial direction) and an axial direction of rotation (thrust direction) by a fluid bearing and rotates at 100,000 revolutions per minute or more.
[0002]
[Prior art]
FIG. 3 is a perspective view of a first conventional printed circuit board boring machine, and FIG. 4 is a front sectional view of a spindle holding portion.
[0003]
In FIG. 3, a table 1 is supported by an X-axis direction drive system 2 and is movable on a bed 3 in an arrow X direction. The column 4 is fixed to the bed 3 so as to straddle the table 1. The cross slide 5 is supported by a Y-axis direction drive system 6 and is movable on the column 4 in the arrow Y direction. The housing 7 is supported by a guide 8 arranged on the cross slide 5, and is movable in the direction of arrow Z. The motor 9 moves the housing 7 through the ball screw 10 in the Z-axis direction. The spindle 20 is supported by the housing 7.
[0004]
The CNC device 11 controls the X, Y, and Z axes. The cooling device 12 cools the spindle 20. A printed board 13 is mounted on the upper surface of the table 1.
[0005]
As shown in FIG. 4, the spindle 20 includes a rotor 21 and a body 22 that rotatably supports the rotor 21.
[0006]
The rotor 21 has a flange portion 21b. Hereinafter, a portion other than the flange portion 21b of the rotor 21 is referred to as a trunk portion 21a. In the vicinity of the center of the body 21a in the direction of the axis O, a rotor 23 formed of a copper material in an end ring shape is disposed.
[0007]
Inside the body 22, a hole 24 having a gap of about several μm with the outer periphery of the rotor 21 is formed. Air radial bearings 25 and 26 are arranged at positions of the hole 24 facing the body 21a. A plurality of compressed air outlets constituting the air radial bearings 25 and 26 are arranged in a plane parallel to the axis O. Air thrust bearings 27 and 28 are arranged on both sides of the flange 21b in the direction of the axis O. A plurality of compressed air outlets constituting the air thrust bearings 27 and 28 are arranged in a plane perpendicular to the axis O. The length of the hole 24 at the portion where the flange portion 21b is fitted in the direction of the axis O is K. The air radial bearings 25 and 26 and the air thrust bearings 27 and 28 are respectively connected to a compressed air source (not shown).
[0008]
A coil (stator) 29 is arranged at a position facing the rotor 23 of the body 22. The coil 29 is connected to an inverter power supply not shown. A drill 31 is held at the tip of the rotor 21.
[0009]
Next, the operation of the conventional printed board drilling machine will be described.
[0010]
The air radial bearings 25 and 26 and the air thrust bearings 27 and 28 are operated, that is, compressed air is supplied to the air radial bearings 25 and 26 and the air thrust bearings 27 and 28 to support the rotor 21 in the radial direction and the axis O direction. I do. Next, a current is supplied to the coil 29 to rotate the rotor 21 around the axis O. In this state, the axis O is positioned at the processing position by moving the table 1 and the cross slide 5 in the X and Y directions, respectively. Thereafter, the motor 9 is operated to lower the drill 31 to a predetermined height, and a hole is formed in the printed circuit board 13.
[0011]
Since the rotor 21 is supported by the air radial bearings 25 and 26 and the air thrust bearings 27 and 28, the rotor 21 can rotate at high speed, and a hole having a diameter of about 0.2 mm can be machined at high speed and with high accuracy. Was.
[0012]
FIG. 5 is a perspective view of a second conventional printed circuit board boring machine, and FIG. 6 is a front sectional view of a spindle holding portion. The same reference numerals as those in FIGS. Description is omitted.
[0013]
In the case of the second conventional printed circuit board boring machine, the flange 21 b is arranged at the end of the rotor 21. The flange portion 21b is held by a case 40 having the air thrust bearings 27 and 28. The case 40 is supported by an output shaft of a linear motor such as a linear motor, and is movable in the Z direction.
[0014]
In the case of this printed circuit board boring machine, it is only necessary to move the case 40 having a smaller mass than the body 22 when the drill 31 is moved up and down. In addition to reducing the capacity of No. 9, the processing speed could be improved.
[0015]
[Problems to be solved by the invention]
However, since the case 40 and the body 22 are separately configured, the overall length and mass of the rotor 21 are increased. For this reason, if the rotation speed is increased, the rotor 21 is likely to generate vibration, and the rotation speed cannot be improved. Therefore, for example, when drilling a hole with a drill 31 having a diameter of 0.1 mm, the practical working depth was about 2 mm.
[0016]
An object of the present invention is to solve the above-mentioned problems in the prior art, and to provide a spindle that can achieve a practical working depth of 3 mm or more even with a drill having a diameter of 0.1 mm, for example.
[0017]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a rotor having a body portion with a flange portion having a larger diameter than the body portion, and a hole for accommodating the flange portion and a part of the body portion with a small gap therebetween. A radial fluid bearing disposed at a position facing the radial direction of the body portion of the hole, and a fluid bearing disposed on both sides in the axial direction of rotation of the flange portion, and the rotor is radially and axially rotated. And a body configured to support the flange portion, the length of the hole accommodating the flange portion in the axial direction of the rotation is longer than the sum of the thickness of the flange portion and the distance L, and A control device is provided for controlling the pressure of the fluid supplied to the axial fluid bearing, and the control device changes the pressure of the fluid supplied to the fluid bearing in the axial direction of the rotation so as to move the rotor by the distance L. Example In wherein the positioning in the axial direction of the rotation.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on the illustrated embodiments.
[0019]
FIG. 1 is a front sectional view of a spindle according to the present invention, and FIG. 2 is a perspective view of a printed circuit board drilling machine to which the spindle according to the present invention is applied. The description is omitted by attaching the reference numerals.
[0020]
The length M of the hole 24 in the portion where the flange portion 21b fits in the axis O direction is the length K of the hole 24 in the axis O direction in FIG. 4 (the thickness of the flange portion 21b and the air thrust bearings 27 and 28 form). (The sum with the air gap).
[0021]
The air thrust bearing 27 is connected to the port 50, the air thrust bearing 28 is connected to the port 51, and the ports 50 and 51 are connected to the control device 52. The control device 52 controls the pressure of the compressed air supplied to the air thrust bearings 27 and 28.
[0022]
An annular groove 60 is formed at the center in the thickness direction of the flange portion 21b. The plurality of holes 61 communicate the groove 60 and the surface of the flange portion 21b. Hereinafter, a lower portion of the flange portion 21b of the hole 24 is referred to as a hole 24d, and an upper portion thereof is referred to as a hole 24u. The holes 61 are arranged at equal intervals in the circumferential direction.
[0023]
A sensor (not shown) is arranged between the rotor 21 and the body 22 so that the position of the rotor 21 in the Z direction can be confirmed.
[0024]
Next, the operation of this embodiment will be described. Here, the area above the flange 21b is Su, the area below the flange 21b is Sd (a value obtained by subtracting the cross-sectional area of the body 21a from the area Su), and the weight of the rotor 21 is as follows. ignore.
[0025]
The control device 52 controls the pressure of the air supplied to the port 50 to always be a predetermined value P0. Then, the differential pressure ΔP is controlled by setting the pressure P1 of the air supplied to the port 51 to a value determined by Expression 1.
[0026]
P1 = P0 · Sd / Su + ΔP (Equation 1)
That is, when stopping the rotor 21 at the current position, ΔP is maintained at ΔP = 0, and when lowering the rotor 21 to a desired position, ΔP is kept positive until the rotor 21 moves to a desired height. Keep at the value. When the rotor 21 is raised to a desired height, ΔP is maintained at a negative value until the rotor 21 moves to the desired height.
[0027]
Next, the operation of the groove 60 and the hole 61 will be described.
[0028]
When there is a difference between the pressure inside the hole 24d and the pressure inside the hole 24u, the air moves from the high pressure side to the low pressure side through the groove 60 and the hole 61, and the air flow at this time becomes a radial fluid bearing. Is composed. As a result, the axis O hardly tilts.
[0029]
In addition, although the case where the compressed air is used as the fluid has been described above, water, oil, or the like may be used.
[0030]
Further, according to the present invention, since the overall length of the rotor can be shortened, the outer diameter can be made smaller than that of a conventional rotor. When the outer diameter of the rotor is reduced, the mass of the rotor is reduced, so that the rotation speed of the rotor can be further increased and the moving speed of the rotation of the rotor in the axial direction can be improved.
[0031]
Further, the present invention can be applied to a boring machine other than the printed board boring machine.
[0032]
【The invention's effect】
As described above, according to the present invention, there is provided a spindle in which a rotor provided with a flange portion having a larger diameter than the body portion is supported in a radial direction and a rotation axis direction by a fluid bearing. The axial length of rotation of the hole accommodating the portion is made longer than the sum of the thickness of the flange portion and the distance L, and the pressure of the fluid supplied to the thrust bearings disposed on both sides of the flange portion is controlled. A control device is provided to control the pressure of the fluid supplied to the fluid bearing in the thrust direction to position the rotor in the axial direction of rotation within the range of the distance L. It can be made smaller than. As a result, the number of revolutions of the rotor, that is, the tool, can be increased, and the machining speed can be improved. Further, by providing the means for supporting the flange portion in the radial direction, the deflection of the axis of rotation can be suppressed, and as a result, the processing quality can be improved.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a spindle according to the present invention.
FIG. 2 is a perspective view of a drilling machine to which the spindle according to the present invention is applied.
FIG. 3 is a perspective view of a conventional printed circuit board boring machine.
FIG. 4 is a front sectional view of a spindle holding unit of a conventional printed circuit board boring machine.
FIG. 5 is a perspective view of a conventional printed circuit board boring machine.
FIG. 6 is a front sectional view of a spindle holder of a conventional printed circuit board boring machine.
[Explanation of symbols]
21 Rotor 21b Flange 24 Hole 27 Fluid Bearing 28 Fluid Bearing 52 Controller M Length of Hole 24 for Housing Flange 21b O Axis of Rotation L Travel Distance

Claims (2)

A rotor provided with a flange portion having a larger diameter than the body portion,
A hole for accommodating a part of the flange portion and the body portion with a small gap therebetween is provided, and a radial fluid bearing and a rotation of the flange portion arranged at a position of the hole facing the radial direction of the body portion are provided. A body for supporting the rotor in the radial direction and the axial direction of rotation by fluid bearings arranged on both sides in the axial direction,
The length of the hole accommodating the flange portion in the axial direction of rotation is longer than the sum of the thickness of the flange portion and the distance L, and the pressure of the fluid supplied to the fluid bearing in the axial direction of rotation is reduced. Provide a control device to control,
A spindle, wherein the control device changes the pressure of a fluid supplied to a fluid bearing in the axial direction of the rotation to position the rotor in the axial direction of the rotation within the range of the distance L. The spindle according to claim 1, wherein a means for radially positioning the flange is provided on the flange.

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