JP2008240778A - Automatic-aligning roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent occurrence of a rotational asynchronous component of vibration during rotation of a bearing so as to improve an accuracy of rotation without deteriorating the workability or increasing the assembling cost of bearing parts. <P>SOLUTION: A plurality of oil holes 22 are formed at a substantially axially central portion of an outer ring 20 of the automatic-aligning roller bearing 10. The oil holes 22 are disposed at regular intervals in the circumferential direction of the outer ring 20 and formed to extend in the radial direction. The number of rollers 50 in each row is a number obtained by multiplying the number of the oil holes 22 of the outer ring 20 by a natural number. That is, when the number of the rollers in each row, the number of the oil holes and the natural number are indicated by Z, OH, n, respectively, the relation between the number of the rollers in each row and the number of the oil holes is expressed by the following formula: Z=n×OH. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a self-aligning roller bearing in which a plurality of rolling elements held by a cage in a freely rotatable manner are provided in double rows between outer races and inner races at predetermined intervals in the circumferential direction. More particularly, the present invention relates to a structure for improving the accuracy of rotation.

  In general, in a self-aligning roller bearing that is operated under severe conditions such as high-speed rotation, a circulating oil supply method is employed. The circulating oil supply method is a method in which oil holes along the radial direction are formed at a plurality of locations in the circumferential direction at approximately the center in the axial direction of the outer ring of the self-aligning roller bearing, and oil supply is performed through the oil holes.

Conventionally, a self-aligning roller bearing employing a circulating oil supply method is known (see, for example, Patent Document 1).
FIG. 5 is a cross-sectional view of an essential part showing a self-aligning roller bearing disclosed in Patent Document 1. As shown in FIG.

  Referring to FIG. 5, the self-aligning roller bearing 100 includes two rows of spherical rollers 104 and 105 held by cages 106 and 107 between an outer ring 102 and an inner ring 103 fixed to the housing 101. Become.

At the center of the outer ring 102 in the axial direction, a lubricating oil supply hole 102a is formed along a radial direction at a predetermined location in the circumferential direction. The housing 101 has a lubricating oil supply hole 101a formed at a position facing the hole 102a, and the hole 101a communicates with an oil supply source.
The hole 102a increases the flow rate of the lubricating oil supplied through the corresponding hole 101a of the housing 101, and resists the lubricating oil against the effect of shaking off the bearing rotation, so that the bearing is interposed between the cage central portions 106c and 107c. Reach inside.

  In the conventional self-aligning roller bearing 100 shown in FIG. 5, the lubricating oil can reach the inside of the bearing even under severe use conditions such as high-speed rotation. Here, especially at the time of high-speed rotation, in order to suppress bearing vibration, the self-aligning roller bearing 100 is required to have high rotational accuracy. Therefore, it is necessary to reduce the raceway surface of the inner and outer rings 102 and 103, the shape error of the spherical rollers 104 and 105, and the dimensional difference between the spherical rollers 104 and 105.

  However, there is a limit in terms of processing cost in order to increase the rotational accuracy by reducing the shape error of the raceway surfaces of the inner and outer rings 102 and 103, the spherical rollers 104 and 105, and the dimensional difference between the spherical rollers 104 and 105. It has been difficult to reduce the rotation asynchronous component NRRO (Non Repeatable Run-Out).

  That is, in the outer ring 102, due to the drilling process of the lubricating oil supply hole 102a along the radial direction, the shape error crest of the raceway surface of the outer ring 102 is generated by the number of the holes 102a. For this reason, depending on the number of spherical rollers, a radial runout rotation asynchronous component NRRO appears. Therefore, in particular, in the self-aligning roller bearing used for high-speed rotation, it is required to process the lubricating oil supply hole 102a so as not to affect the shape error of the raceway surface of the outer ring 102.

Therefore, Patent Document 2 discloses a bearing spindle in which the rotation asynchronous component NRRO hardly appears even if there is a shape error on the raceway surface.
FIG. 6 is a cross-sectional view of a main part showing a bearing spindle disclosed in Patent Document 2. As shown in FIG.

  Referring to FIG. 6, the bearing spindle is a combination of a rolling bearing 110 having a number of divisors of 3 or more and the number of rolling elements, and a rolling bearing 111 having a number of rolling elements of 11 or more and not having a divisor. Become.

When the number of rolling elements of the rolling bearing 110 is a number having a divisor of 3 or more, the rotational asynchronous component NRRO of radial shake is suppressed. Further, when the number of rolling elements of the rolling bearing 111 is a prime number of 11 or more that does not have a divisor, the rotational asynchronous component NRRO of the axial shake is suppressed.
Japanese Patent Laid-Open No. 11-141543 (pages 2 and 3, FIG. 2) JP 2000-74048 A (page 4, FIG. 3)

  As shown in FIG. 5 described above, the lubricating oil supply hole 102a is formed in the outer ring of the self-aligning roller bearing along the radial direction at a predetermined position in the circumferential direction. Even if a shape error corresponding to the number of holes 102a occurs on the raceway surface of the outer ring 102 due to the installation process, it is required to suppress the rotational asynchronous component NRRO of radial runout.

  In the self-aligning roller bearing of FIG. 5, the rolling element is not a ball but a spherical roller as in the bearing spindle shown in FIG. 6, and lubricating oil is supplied from a lubricating oil supply hole 102a provided in the bearing outer ring. For this reason, the workability and the assemblability are restricted by the bearing spindle shown in FIG.

  The present invention is a self-aligning roller capable of suppressing the generation of a rotationally asynchronous component of vibration during rotation of the bearing and increasing the accuracy of rotation without increasing the workability and assembly cost of the bearing component. It aims to provide a bearing.

  The above object of the present invention is achieved by the following configurations.

(1) an outer ring having a raceway surface which is a spherical concave surface on the inner peripheral surface;
An inner ring having a double-row raceway surface on the outer peripheral surface;
In a self-aligning roller bearing provided with a plurality of rolling elements which are provided in a plurality of rows at predetermined intervals in the circumferential direction between the raceways of the outer ring and the inner ring, and which are rotatably held by a cage,
A plurality of oil holes are formed in a substantially central position in the axial direction of the outer ring at predetermined positions that are equally distributed in the circumferential direction, respectively, along the radial direction, and
A self-aligning roller bearing, wherein the number of rolling elements in each row is a natural number times the number of oil holes in the outer ring.

(2) an outer ring having a raceway surface which is a spherical concave surface on the inner peripheral surface;
An inner ring having a double-row raceway surface on the outer peripheral surface;
In a self-aligning roller bearing comprising a plurality of rolling elements which are provided in a plurality of rows at predetermined intervals in the circumferential direction between the raceways of the outer ring and the inner ring and which are rotatably held by a cage,
A plurality of oil holes are formed in a substantially central position in the axial direction of the outer ring at predetermined positions that are equally distributed in the circumferential direction, respectively, along the radial direction, and
A self-aligning roller bearing, wherein the number of rolling elements in each row is a number having a divisor of 3 or more.

  In the self-aligning roller bearing described in the above (1), the rotation asynchronous component of the vibration does not appear when the bearing is rotated, and the rotation is highly accurate. Thereby, bearing vibration is suppressed. The vibration suppression effect is noticeable when the bearing rotates at high speed.

  In the self-aligning roller bearing described in the above (2), the rotation asynchronous component of the vibration does not appear when the bearing is rotated, so that the rotation is highly accurate. Thereby, bearing vibration is suppressed. The vibration suppression effect is noticeable when the bearing rotates at high speed.

According to the self-aligning roller bearing of the present invention, it is possible to suppress the generation of a rotational asynchronous component of the vibration during rotation of the bearing without increasing the workability and assembly cost of the bearing parts, thereby improving the accuracy of the rotation. Can be planned.
The self-aligning roller bearing obtained by the present invention is suitably used when low vibration and high durability are required under severe use conditions such as high-speed rotation.

Embodiments of the present invention will be described below with reference to the accompanying drawings.
FIG. 1 is a cross-sectional view of a main part showing a self-aligning roller bearing according to a first embodiment of the present invention, and FIG. 2 shows the number of raceway shape error crests and oil of the outer ring of the self-aligning roller bearing of FIG. It is the schematic which shows the relationship of a hole position.

  Referring to FIGS. 1 and 2, a self-aligning roller bearing 10 according to a first embodiment includes an outer ring 20 having a raceway surface 21 having a spherical concave surface having a single center on an inner peripheral surface, and double rows on the outer periphery. A plurality of inner rings 30 having raceway surfaces 31 and raceways 21 and 31 of the outer ring 20 and the inner ring 30 are provided in two rows at predetermined intervals in the circumferential direction, and are held by the cage 40 so as to be freely rollable. The rolling element (spherical roller) 50 is provided.

  A raceway surface 21 having a single center of the outer ring 20 is formed on the inner peripheral surface of the outer ring 20 in a circular arc shape in cross section. The double-row raceway surfaces 31 of the inner ring 30 are formed of a pair of arcuate raceway surfaces that face the raceway surface 21 of the outer ring 20 and that are continuous in the axial direction (left-right direction in FIG. 1). Furthermore, the rolling elements 50 are held so as to be freely rollable by the retainers 40 for each row.

  Each retainer 40 includes a flange portion 41 extending radially inward at the axially outer end portion and a central portion 42 extending radially outward at the axially inner end portion. Each of the cages 40 is interposed between the inner and outer rings 20 and 30 with the central portion 42 in a back-to-back state.

Near the center of the outer ring 20 in the axial direction, a plurality (six in FIG. 2) of oil holes 22 are arranged along the radial direction at predetermined positions (at 60 ° in FIG. 2) that are equally distributed in the circumferential direction. Is formed.
Further, the number of rolling elements 50 in each row is a natural number times the number of oil holes 22 in the outer ring 20. That is, when the number of rolling elements in each row is Z, the number of oil holes is OH, and the natural number is n, Z = n × OH.

In the self-aligning roller bearing of the second embodiment (not shown), the number of rolling elements in each row is a number having 3 or more divisors of 2 to 10.
Other configurations and operations are the same as those in the first embodiment.

FIG. 3 is a schematic diagram schematically showing the force acting on the inner ring when the number of rolling elements Z is a natural number n times the number B of shape errors, and FIG. It is a graph which shows the relationship between the number of shape error crests contained in the outer ring raceway surface and the amplitude in the case.
Also, Table 1 shows the radial bearing runout by changing the outer ring shape error peak component and the number of rolling elements, using the inner and outer ring raceway surface shape error, rolling element shape error, rolling element size difference, etc. of the rolling bearing as input parameters at the same time. It is a table | surface which shows the result of having calculated | required the maximum value of a rotation asynchronous component.

  A theoretical calculation formula that theoretically calculates the radial motion of the shaft center associated with the rotation angle of the rolling bearing from the balance of internal forces using the inner and outer ring raceway surface shape errors and the number of rolling elements of the rolling bearing as parameters is known. (Ono Ukyo et al., THEORETICAL ANALYSIS OF SHAFT VIBRATION SUPPORTED BY A BALL BEARING WITH SMALL SINUSOIDAL WAVINESS, IEEE TRANSACTION ON MAGNETICS, Vol.1, No.3, MAY 1996, p1709-1714).

Based on this theoretical calculation formula, using an analysis program with the inner and outer ring raceway surface shape error, rolling element shape error, rolling element size difference, etc. as input parameters at the same time, outer ring shape error peak component (2-10 peaks) and rolling element By changing the number (7 to 20), the maximum value of the rotational asynchronous component of the radial runout was obtained. That is, the maximum value of the rotation asynchronous component was calculated as 256 points per round, 50 rounds, the total amplitude of the shape error was 2 μm, the shape error of the rolling element, and no dimensional difference.
The results are shown in Table 1.

  Here, since the limit of the resolution of the sensor used for shake measurement is 0.001 μm, the value less than 0.001 μm is set to 0 in consideration of the verification of the calculated value. The shape error given to the outer ring raceway surface was an ideal sine wave represented by A · sinBθ (A: half amplitude (1 μm) of shape error, B: number of error peaks). Even when a shape error is given to the inner ring, the same result as in Table 1 can be obtained.

From Table 1, the following can be understood with respect to the relationship between the number of rolling elements Z and the shape error crest B of the inner and outer ring raceway surfaces.
As shown in FIG. 3, when the number of rolling elements Z is a multiple (natural number n times) of the shape error mountain number B (Z = nB), that is, the low frequency mountain component of the raceway surface shape error of the inner and outer rings is If the shape error crest B is a divisor, a force acts on the inner ring as shown in FIG. 3 when the bearing rotates, and as shown by the thick frame in Table 1, the rotational asynchronous component NRRO of radial runout Does not appear.

  Therefore, in the self-aligning roller bearing 10 of the first embodiment, the number of rolling elements Z in each row is a natural number multiple of the number of oil holes OH in the outer ring 20, so that the rotation asynchronous component NRRO does not appear when the bearing rotates. In particular, bearing vibration during high-speed rotation is suppressed.

In addition, from Table 1, the following (1) and (2) are also understood.
(1) When the number of rolling elements is an odd number such as 7, 9, 11, 13, and the divisor is small, a rotationally asynchronous component NRRO of radial shake appears with an error number other than the number of shape peaks that is a divisor.
(2) When the number of rolling elements is 12, 18, that is, when the number of rolling elements is equal to the number having many divisors, the rotationally asynchronous component NRRO of radial shake does not appear up to the shape error crest of 10 crests.
In other words, the more divisors, the more often the rotationally asynchronous component NRRO of radial shake does not appear even when the number of shape error peaks is not a divisor.

On the other hand, when harmonic analysis (harmonic analysis) is performed on the shape error data obtained by measuring the roundness of the inner and outer ring raceway surfaces, the result shown in FIG. 4 is obtained. In FIG. 4, as in the case of Table 1, the value less than 0.001 μm is set to 0 in consideration of the verification of the calculated value.
As can be understood from FIG. 4, the main low-frequency peak components of the shape error of the inner and outer ring raceway surfaces are generally mainly the shape error peak components of 2 to 10 peaks.

  From the above, it is generally understood that a number having a large number of integers from 2 to 10 as divisors may be set as the number of rolling elements. If the number of rolling elements is set to 12 or 18, the maximum rotational asynchronous component value in the radial direction is 0 regardless of the number of shape error peaks of 2 to 10 peaks. 12 and 18 each have four divisors from 2 to 10. That is, in 12, the divisors from 2 to 10 are 2, 3, 4, 6, and in 18, the divisors from 2 to 10 are 4, 3, 6, and 9.

  Therefore, it is understood that if the number of rolling elements has four or more divisors of the main low frequency peak components of the shape error of the inner and outer ring raceway surfaces, it is effective in reducing the rotational asynchronous component of radial runout. Is done. Further, even when 16 having 3 of the divisors 2, 4 and 8 from 2 to 10 is set as the number of rolling elements, the maximum rotational asynchronous component value except for 5 peaks is 0, and the rotational asynchronous component of radial runout NRRO can be reduced.

  That is, in the self-aligning roller bearing of the second embodiment, since the number of rolling elements in each row is a number having a divisor of 2 to 10 or more, the rotation asynchronous component NRRO does not appear when the bearing rotates, In particular, bearing vibration during high-speed rotation is suppressed.

  As described above, according to each embodiment described above, the number of rolling elements 50 in each row is a natural number multiple of the number of oil holes 22 of the outer ring 20 (first embodiment), or a divisor from 2 to 10. It is a number (second embodiment) having 3 or more.

  Therefore, without increasing the workability and assembly cost of the bearing parts, it is possible to suppress the generation of the rotational asynchronous component NRRO of the radial runout during the rotation of the bearing, and to improve the accuracy of the rotation. Thereby, especially the bearing vibration at the time of high speed rotation can be reduced, and the reliability and durability of the self-aligning roller bearing 10 can be improved.

It is principal part sectional drawing which shows the self-aligning roller bearing which is 1st Embodiment of this invention. FIG. 2 is a schematic diagram showing the relationship between the number of raceway surface shape errors of the outer ring of the self-aligning roller bearing of FIG. 1 and the oil hole position. It is the schematic which shows typically the force which acts on an inner ring | wheel, when the number of rolling elements Z is the natural number n times the number B of shape errors. It is a graph which shows the relationship between the number of shape error crests contained in the outer ring raceway surface and the amplitude when the number of oil holes is six. FIG. 3 is a cross-sectional view of a main part showing a self-aligning roller bearing disclosed in Patent Document 1. FIG. 10 is a cross-sectional view of a main part showing a bearing spindle disclosed in Patent Document 2.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Self-aligning roller bearing 20 Outer ring 21 Single row raceway surface 22 Oil hole 30 Inner ring 31 Double row raceway surface 40 Cage 50 Rolling element (spherical roller)

Claims (2)

An outer ring having a raceway surface which is a spherical concave surface on the inner peripheral surface;
An inner ring having a double-row raceway surface on the outer peripheral surface;
In a self-aligning roller bearing provided with a plurality of rolling elements which are provided in a plurality of rows at predetermined intervals in the circumferential direction between the raceways of the outer ring and the inner ring, and which are rotatably held by a cage,
A plurality of oil holes are formed in a substantially central position in the axial direction of the outer ring at predetermined positions that are equally distributed in the circumferential direction, respectively, along the radial direction, and
A self-aligning roller bearing, wherein the number of rolling elements in each row is a natural number times the number of oil holes in the outer ring. An outer ring having a raceway surface which is a spherical concave surface on the inner peripheral surface;
An inner ring having a double-row raceway surface on the outer peripheral surface;
In a self-aligning roller bearing provided with a plurality of rolling elements which are provided in a plurality of rows at predetermined intervals in the circumferential direction between the raceways of the outer ring and the inner ring, and which are rotatably held by a cage,
A plurality of oil holes are formed in a substantially central position in the axial direction of the outer ring at predetermined positions that are equally distributed in the circumferential direction, respectively, along the radial direction, and
A self-aligning roller bearing, wherein the number of rolling elements in each row is a number having a divisor of 3 or more.

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