JP3495515B2 - Method for correcting balance of rotating shaft supported by hydrostatic bearing - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention, for example, in a polishing apparatus having a rotary shaft supported through a radial static pressure bearing, is supported by a static pressure bearing used when the grindstone is attached when exchanging the grindstone. The present invention relates to a method for correcting the balance of a rotating shaft.

[0002]

2. Description of the Related Art Conventionally, for example, in a polishing apparatus having a rotary shaft supported by a housing via radial static pressure bearings, when a grindstone is attached to the rotary shaft to correct the balance, as shown in FIG. , The displacement sensor 51 is installed toward the bearing center O, and the mark M that serves as a reference of the phase at the time of balance correction is attached to the rotary shaft 50, so that the runout E of the rotary shaft 50 and the phase of the mark M due to imbalance I was trying to detect.

The eccentric direction or the eccentric direction is 1
A known trial weight W is attached to an arbitrary position in the opposite direction of 80 ° to rotate the rotary shaft 50, and at this time, the displacement sensor 51
The runout E of the rotary shaft 50 detected by the above is compared with the runout E of the rotary shaft when the trial weight W is not attached,
I was trying to determine the mass of the modified weight.

[0004]

However, in the above-described conventional method for correcting the balance of the rotary shaft supported by the hydrostatic bearing, when the rotary shaft 50 is rotated, the dynamic pressure is added to the static bearing rigidity at rest. Bearing rigidity during rotation (Fig. 4
Since the hatched portion in (a) occurs, the rotating shaft 50 is eccentric to a phase having an angle Θ with the eccentric direction. Further, since the eccentricity angle Θ changes depending on the magnitude of the unbalance amount, it cannot be said that the eccentric direction is always accurate, and in addition, the trial weight W is used to obtain the unbalance amount of the rotating shaft 50. Therefore, even if the eccentric direction is determined, until the runout E of the rotary shaft 50 is almost eliminated,
The trial weight W must be repeatedly replaced in the eccentric direction or in the vicinity of the eccentric direction, and as a result, it is troublesome and difficult to correct the balance, and a lot of time is spent. Therefore, it has been a conventional problem to solve this problem.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art. It is possible to improve the workability of correction and to shorten the correction time, and also to perform precise balance correction of the rotary shaft. It is an object of the present invention to provide a method for correcting the balance of a rotary shaft supported by a hydrostatic bearing that is possible.

[0006]

When a rotating shaft supported by a radial hydrostatic bearing is rotated, as shown in FIG. 1, in addition to static bearing static pressure ks at static time, dynamic bearing causes rotary bearing as well. The rigidity Kd ′ and the bearing rigidity Kd due to the squeeze force are generated.

At this time, if the total bearing rigidity kd including the stationary bearing rigidity ks, the rotating bearing rigidity Kd ', and the bearing rigidity Kd due to the squeeze force can be measured in advance, the rotating shaft 1 during rotation shown in FIG. The centrifugal force F can be calculated based on F = e × kd (F: centrifugal force due to unbalance (unbalanced amount)) by measuring the deflection e of kd
′ Is generated in a direction delayed by an angle θ (eccentricity angle θ) from the eccentric direction, and depends on the magnitude of the centrifugal force F. Further, the bearing rigidity kd due to the squeeze force is the deflection (eccentricity amount) e and Since it depends on the rotation frequency, it is difficult to measure the total bearing stiffness kd in advance.

However, the static bearing stiffness k due to static pressure
If s does not depend on rotation, and the bearing rigidity kd ′ during rotation due to dynamic pressure and the bearing rigidity kd due to squeeze force are not affected by changes in supply pressure, in FIG. Stationary bearing stiffness ks1, total bearing stiffness kd1 and supply pressure P at pressure P1
When the static bearing rigidity ks2 at 2 is the total bearing rigidity kd2, kd2-ks2 = α2, kd1-ks1 = α1, α1≈
It is understood that the relationship of α2 (= α) is established, and therefore, the centrifugal force F can be calculated from the above F = e × kd by measuring the stationary bearing stiffnesses ks1 and ks2 and the deflection e that do not depend on rotation.

If the eccentric angles + θ and -θ are symmetrical in the rotational direction when the rotary shaft 1 is rotated in the forward and reverse directions, the eccentric angles + θ and -θ are intermediate. It can be seen that the position is in the eccentric direction.

A balance correction method for a rotary shaft supported by a hydrostatic bearing according to the present invention is based on the above-mentioned point of view, and the balance correction for a rotary shaft supported by the hydrostatic bearing according to claim 1 is performed. According to the method, when correcting the balance of the rotary shaft supported by the radial static pressure bearing, the stationary bearing rigidity ks1 and the supply pressure P2 at the supply pressure P1 to the radial static pressure bearing in the state where the rotary shaft is stationary.
Bearing static rigidity ks2 at rest, and then while rotating the rotating shaft, the runout ed1 of the rotating shaft at the supply pressure P1 and the runout ed2 of the rotating shaft at the supply pressure P2 with respect to the radial hydrostatic bearing are measured. After that, the total bearing rigidity obtained by adding the stationary bearing rigidity ks1 to the rotating bearing rigidity and the bearing rigidity due to the squeeze force is set to kd1, and the stationary bearing rigidity ks2 is the rotating bearing rigidity and the bearing rigidity due to the squeeze force. When the added total bearing rigidity is kd2, it is established that the bearing rigidity during rotation and the bearing rigidity due to the squeeze force are not affected by changes in the supply pressure. Kd2-ks2 = α2, kd1-ks1 = α1, α1 ≒
An expression ed1 × kd1 for obtaining a centrifugal force F due to imbalance generated when kd1 = α + ks1 and kd2 = α + ks2 obtained from the relationship of α2 (= α) are respectively rotated under the supply pressure P1 and the supply pressure P2. = F, ed2 × kd2 = F, respectively, and the expression ed1 × ed2 × (ks2-ks1) / (ed1-ed obtained by eliminating α)
2) The centrifugal force F is calculated on the basis of = F 2, and the mass m of the modified weight to be attached on the circumference of the radius r preset on the rotation axis is defined by the radius r, the angular velocity ω and the centrifugal force F.
F = mrω ² is determined, and the intermediate position of each eccentric angle measured by rotating the rotating shaft forward and backward is determined as the eccentric direction.
The structure of the method for correcting the balance of the rotary shaft supported by the hydrostatic bearing is used as means for solving the conventional problems.

Further, as an embodiment of the method for correcting the balance of the rotary shaft supported by the hydrostatic bearing according to the present invention, in claim 2, a plurality of correction weight mounting portions are provided on the circumference of the radius r. Is characterized by.

A balance correction method for a rotary shaft supported by a static pressure bearing according to the present invention is a balance correction for a rotary shaft supported by a radial static pressure bearing using hydraulic pressure, and a so-called static pressure gas using air pressure. It can be used for any of the balance correction of the rotating shaft supported by the bearing,
Since the rotation resistance is low and the bearing rigidity is low, it is desirable to apply it to the balance correction of the rotary shaft supported by the hydrostatic gas bearing, which can measure a minute displacement of the rotary shaft.

[0013]

The method for correcting the balance of the rotary shaft supported by the hydrostatic bearing according to claim 1 of the present invention has the above-described structure, and therefore, the balance of the rotary shaft supported by the radial hydrostatic bearing is corrected. , The stationary bearing rigidity ks1 at the supply pressure P1 and the stationary bearing rigidity ks at the supply pressure P2 for the radial hydrostatic bearing with the rotating shaft stationary.
2 is measured, and then, while rotating the rotating shaft, the runout of the rotating shaft at the supply pressure P1 to the radial hydrostatic bearing is ed1.
If the runout ed2 of the rotating shaft at the supply pressure P2 is measured, the centrifugal force F generated by the imbalance is obtained, and each eccentric angle when the rotating shaft is normally rotated and reversely rotated is measured. In that case, the intermediate position is required as the eccentric direction, so it is not necessary to replace the trial weight, which improves the workability of the correction and shortens the correction time, and also enables precise balance correction of the rotary shaft. Will be done.

According to the method for correcting the balance of the rotary shaft supported by the hydrostatic bearing according to the second aspect of the present invention, since the above-mentioned configuration is adopted, the correction weight can be easily attached, and the correction workability is further improved. Will be improved and the correction time will be significantly shortened.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view of a balance correcting method of a rotary shaft supported by a hydrostatic bearing according to the present invention, and FIGS. 2 and 3 are rotations supported by a hydrostatic bearing according to an embodiment of the present invention. 4 illustrates a main shaft portion of a polishing apparatus to which a shaft balance correction method is applied.

As shown in FIG. 2, the main shaft portion 10 of this polishing apparatus is housed in a housing 11 and one end portion (the end portion on the right side in the drawing) of the main shaft portion 10 is connected to a polishing apparatus driving portion (not shown). And a radial static pressure bearing 12 for supporting the rotating shaft 1 to which a grindstone T as a tool is attached at the other end (the end on the left side in the drawing), and the small diameter parts 1a provided at both ends of the rotating shaft 1, 12, an oil feed pump 13 for sending oil under pressure to the radial static pressure bearing 12 via the oil feed passage 13a, an air source 14 communicating with the oil feed passage 13a and the air supply passage 14a, and an air feed passage 14a. The check valve 15 provided, the displacement meter 16 attached to the housing 11 so as to face the small diameter portion 1a located on one end side of the rotary shaft 1, and the housing 1
1 is provided with a rotation detector 17 attached so as to face the small diameter portion 1a located on the other end side of the rotary shaft 1, and a displacement meter 16 for measuring the shake of the rotary shaft 1 and a rotation for measuring the phase of the shake The detector 17 is connected to the arithmetic unit 18.

In the main shaft portion 10 of the polishing apparatus, during the polishing process, the oil feed pump 13 is operated to feed the oil having a pressure higher than that of the compressed air sent from the air source 14 to the radial static pressure bearings 12 and 12 for hydraulic pressure. Supports the rotating shaft 1 by
On the other hand, during the balance correction, the oil feed pump 13 is stopped to send compressed air to the radial static pressure bearings 12 and 12 to support the rotary shaft 1 by air pressure.

Further, in the main shaft portion 10 of this polishing apparatus, the grindstone T is held between the plate 20 fixed to the center of the other end surface of the rotary shaft 1 by a bolt (not shown) and the other end surface of the rotary shaft 1. In this case, as shown in FIG. 3, the plate 20 is provided with a plurality of screw holes (correction weight attaching portions) 20a located on the circumference of the radius r at substantially equal intervals.

In the main shaft portion 10 of this polishing apparatus, when correcting the balance of the rotary shaft 1 with the grindstone T attached, first, the oil feed pump 13 is stopped and the rotary shafts of the radial static pressure bearings 12 and 12 are rotated. So that 1 is pneumatically supported.

Next, in a state where the rotary shaft 1 is stationary, a predetermined load is applied to the grindstone T as the supply pressure P1 to the radial static pressure bearings 12, 12, and the stationary bearing rigidity ks at this time is obtained.
1 is measured by the displacement meter 16, a predetermined load is also applied to the grindstone T as the supply pressure P2, and the stationary bearing rigidity ks2 at this time is measured by the displacement meter 16.

Subsequently, while rotating the rotary shaft 1, the rotary shaft runout ed1 at the supply pressure P1 and the rotary shaft runout ed at the supply pressure P2 are applied to the radial static pressure bearings 12, 12.
2 is measured by the displacement gauge 16.

Here, the stationary bearing rigidity ks1 is added to the rotating bearing rigidity Kd 'and the bearing rigidity Kd due to the squeeze force to obtain the total bearing rigidity kd1, and the stationary bearing rigidity k is obtained.
If the bearing rigidity Kd 'during rotation and the bearing rigidity Kd due to the squeeze force are added to s2 to obtain the total bearing rigidity kd2, the bearing rigidity Kd' during rotation and the bearing rigidity Kd due to the squeeze force are not affected by changes in the supply pressure. , As shown in FIG. 1, kd2-ks2 = α2, kd1-ks1 = α1, α1≈
The relationship of α2 (= α) is established.

That is, kd1 = α + ks1, kd2 =
An expression for determining a centrifugal force F due to imbalance that occurs when the rotating shaft 1 is rotated under the supply pressure P1 and the supply pressure P2 with α + ks2 ed1 × kd1 = F, ed2 × kd
2 = F, respectively, and ed1 × ed2 × (ks2-ks1) / (ed1-ed obtained by eliminating α)
2) = F 2, the centrifugal force F is calculated using the stationary bearing rigidity ks1 at the supply pressure P1, the rotational shaft runout ed1 and the stationary bearing rigidity ks2 at the supply pressure P2, the rotational shaft runout ed2.

Next, the mass m of the screw (correction weight) w attached to the plurality of screw holes 20a provided on the circumference of the plate 20 having the radius r is defined by the radius r, the angular velocity ω, and the centrifugal force F and F. = Mrω ² .

After that, the rotary shaft 1 is rotated in the forward and reverse directions, and the phase of the deflection e of the rotary shaft 1 detected by the displacement gauge 16 and the rotation pulse obtained from the rotation detector 17 are calculated each time. The eccentric angle + θ, -θ is measured and the intermediate position between the eccentric angles + θ, -θ is determined as the eccentric direction z. The direction is 180 ° opposite to the eccentric direction z and the radius r The screw w determined as described above is attached to the screw hole 20a located on the circumference of.

Therefore, in the method of correcting the balance of the rotary shaft supported by the hydrostatic bearing, the static bearing rigidity ks1 at the supply pressure P1 and the static bearing rigidity ks2 at the supply pressure P2 which can be accurately measured in advance, and the rotation Runout ed1 of the rotating shaft at the supply pressure P1 that can be measured by rotating the shaft 1.
And the runout ed2 of the rotating shaft at the supply pressure P2, the centrifugal force F generated by the imbalance is obtained, and the eccentric angles + θ, − measured each time by rotating the rotating shaft 1 in the forward and reverse directions. Since the eccentric direction is obtained by using θ, precise balance correction of the rotary shaft 1 is performed, and in addition, since it is not necessary to replace the trial weight, which has been conventionally performed, the correction workability is improved. Improve and
The correction time can be shortened.

Further, since the plate 20 for mounting the grindstone 4 on the rotary shaft 1 is provided with a plurality of screw holes 20a located on the circumference of the radius r thereof at substantially equal intervals, the screw w as a correction weight is The installation becomes simple, and as a result, the workability of the correction is further improved and the correction time is greatly shortened.

In the above-described embodiment, the method of correcting the balance of the rotating shaft according to the present invention is applied to the main shaft portion 10 of the polishing apparatus, but the present invention is not limited to this.

The detailed construction of the method for correcting the balance of the rotary shaft according to the present invention is not limited to the above-mentioned embodiment.

[0031]

As described above, according to the first aspect of the present invention.
In the method for correcting the balance of the rotary shaft according to the present invention, since the configuration is as described above, when the balance of the rotary shaft supported by the radial static pressure bearing is corrected, the supply pressure P1 to the radial static pressure bearing is kept stationary while the rotary shaft is stationary. The static bearing rigidity ks1 at static pressure and the static bearing rigidity ks2 at supply pressure P2 were measured, and then the runout e of the rotating shaft at the supply pressure P1 against the radial static pressure bearing while rotating the rotating shaft was measured.
The centrifugal force F generated by the imbalance can be obtained only by measuring the runout ed2 of the rotating shaft at d1 and the supply pressure P2. In addition, the eccentricity when the rotating shaft is rotated forward and backward By just measuring each angle, the intermediate position can be obtained as the eccentric direction, and as a result, the balance adjustment of the rotating shaft can be performed extremely precisely. In addition, the trial weight replacement work that has been done conventionally Since it is not necessary to perform the above, it is possible to achieve a very excellent effect that it is possible to improve the workability of correction and shorten the correction time.

In the method for correcting the balance of the rotary shaft supported by the hydrostatic bearing according to the second aspect of the present invention, since the above-mentioned configuration is adopted, the correction weight can be easily attached,
Therefore, a very excellent effect that the correction workability is further improved and the correction time is greatly shortened is brought about.

[Brief description of drawings]

FIG. 1 is a graph (a) showing the relationship between bearing rigidity and supply pressure for explaining the method for correcting the balance of a rotating shaft according to the present invention.
FIG. 8B is an explanatory diagram (b) of an eccentricity state when the rotation shaft is rotating.

FIG. 2 is a cross-sectional explanatory view showing a main shaft portion of a polishing apparatus to which a method for correcting balance of a rotary shaft according to the present invention is applied.

3 is a front explanatory view of a plate fixed to a main shaft portion of the polishing apparatus in FIG.

4A and 4B are explanatory views of an eccentricity condition when a rotating shaft is rotating, showing a conventional method of correcting the balance of the rotating shaft; and FIG. 4A is an explanatory diagram of a phase in which a shake of the rotating shaft and a rotating pulse are overlapped with each other. b).

[Explanation of symbols]

1 rotation axis 12 radial hydrostatic bearings 20a Screw hole (correction weight mounting part) w screw (correction weight)

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yu Owada 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Manabu Wakuda 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Inventor Riichi Otani No. 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Minoru Ota No. 2, Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72 ) Inventor Katsutoshi Miyahara 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd. (56) Reference JP 63-96532 (JP, A) JP 2-224944 (JP, A) Special Kaihei 5-65942 (JP, A) JP-A-58-42944 (JP, A) Actual Kaihei 4-63316 (JP, U) Actual Kaihei 4-63340 (JP, U) (58) Field (Int.Cl. ^7, DB name) B23Q 11/00 F16F 15/32 F16C 32/06

Claims (2)

(57) [Claims] 1. When correcting the balance of a rotary shaft supported by a radial static pressure bearing, the static bearing rigidity ks1 and the supply pressure at a supply pressure P1 to the radial static pressure bearing in a state where the rotary shaft is stationary. The static bearing rigidity ks2 at P2 is measured, and subsequently, while rotating the rotary shaft, the runout ed1 of the rotary shaft at the supply pressure P1 and the runout ed2 of the rotary shaft at the supply pressure P2 with respect to the radial hydrostatic bearing are measured. After the measurement, the total bearing rigidity obtained by adding the bearing rigidity during rotation ks1 to the bearing rigidity during rotation and the bearing rigidity due to the squeeze force is kd1, and the stationary bearing rigidity ks2 is the bearing rigidity during rotation and the bearing rigidity due to the squeeze force. When the total bearing rigidity including the above is set to kd2, the bearing rigidity during rotation and the bearing rigidity due to the squeeze force are affected by changes in the supply pressure. Established by the absence kd2-ks2 = α2, kd1-ks1 = α1, α1 ≒
An expression ed1 × kd1 for obtaining a centrifugal force F due to imbalance generated when kd1 = α + ks1 and kd2 = α + ks2 obtained from the relationship of α2 (= α) are respectively rotated under the supply pressure P1 and the supply pressure P2. = F, ed2 × kd2 = F, respectively, and the expression ed1 × ed2 × (ks2-ks1) / (ed1-ed obtained by eliminating α)
2) The centrifugal force F is calculated on the basis of = F 2, and the mass m of the modified weight to be attached on the circumference of the radius r preset on the rotation axis is defined by the radius r, the angular velocity ω and the centrifugal force F.
The bearing is supported by a hydrostatic bearing characterized by determining from F = mrω ² and determining the intermediate position of each eccentric angle measured by rotating the rotating shaft in the forward and reverse directions as the eccentric direction. Rotation axis balance correction method. 2. A method for correcting balance of a rotary shaft supported by a hydrostatic bearing according to claim 1, wherein a plurality of correction weight mounting portions are provided on a circumference of a radius r of the rotary shaft.