JP2003065339A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling bearing which suitably restrict the skew of roller and lengthens the useful life by reducing the maximum mutual difference ratio for the dimensional precision of rollers produced, especially for all rollers used, and the maximum roundness ratio for all rollers used. SOLUTION: The rolling bearing is equipped with an inner ring 2, an outer ring 1, a plurality of rollers 3 which are arranged between the inner ring 2 and the outer ring 1. For roller diameters for all rollers used, the maximum mutual difference ratio M which is defined by the following formula (1) is less than 1.0, and the maximum roundness ratio P which is defined by the following formula (2) is less than 0.3.

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing, and more particularly to a rolling bearing such as a self-aligning roller bearing which has a long life by suppressing skew of a roller. 2. Description of the Related Art Generally, a self-aligning roller bearing including a double-row self-aligning roller bearing has a self-aligning property, so that even if an outer ring or an inner ring inclines due to a mounting error or an impact load. The state of contact of the rollers with the inner and outer rings does not change, so that the occurrence of an abnormal load can be prevented and the radial load capacity can be increased. For this reason, self-aligning roller bearings are widely used as various industrial bearings such as roll neck bearings for various types of papermaking machines and vehicle bearings. [0003] However, in this self-aligning roller bearing, since the rollers have a large contact angle, the rolling speed at both ends of the rollers differs during the operation of the bearing.
Rollers are likely to roll (skew in the rollers) with slanting and sliding. This skew generates heat and promotes wear and fatigue of the bearing. Therefore, if such a state continues, the life may be significantly reduced. As a method for suppressing skew at this time, for example, Japanese Patent Publication No. 57-61933 and Japanese Patent Publication No.
The technique disclosed in JP-A-8-34686 is known. Among them, the technology disclosed in Japanese Patent Publication No. 57-61933 relates to a self-aligning roller bearing, in which the sliding friction coefficient of the contact portion between the inner ring and the outer ring is determined. Under normal load conditions, the skew moment due to the frictional force against the outer ring rollers is controlled to be smaller than or equal to the skew moment due to the frictional force against the inner ring rollers under normal load conditions. Is set to zero or a small positive skew angle. The technique disclosed in Japanese Patent Publication No. 58-34686 relates to a self-aligning roller bearing having skew controllability. The radius of curvature of the part is larger than the radius of curvature of the inner track, the radius of curvature of the contour is constant and the radius of curvature of the center part of the roller is greater than the radius of curvature of the outer track, and the radius of curvature of the contour is constant and the roller Are smaller than the radius of curvature of the contour of the central portion of the image. However, these conventional methods for suppressing skew have the following problems. That is, JP-B-57-61933 and JP-B-58-34686 do not consider the influence of the processing accuracy on the skew of rollers used in a plurality of bearings. In some cases, the skew cannot be controlled properly depending on the variation in the skew. SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above-mentioned problems, and has as its object the dimensional accuracy of manufactured rollers, in particular, the maximum mutual accuracy with respect to the roller diameters of all rollers used. An object of the present invention is to provide a rolling bearing that appropriately suppresses roller skew by reducing the difference ratio and the maximum roundness ratio for all the rollers used, thereby extending the life. In order to solve the above-mentioned problems, a rolling bearing according to a first aspect of the present invention comprises an inner ring, an outer ring, and a plurality of rollers arranged between the inner ring and the outer ring. In a rolling bearing provided with a roller and a cage for holding the roller, the maximum mutual difference ratio M defined by the following equation (1) is 1.0 or less for all the roller diameters of the rollers used. And the maximum roundness ratio P defined by the following equation (2) is 0.3 or less for all the rollers used. [0009] Here, D _MAX : the maximum value among all the used roller diameters D _MIN : the minimum value among all the used roller diameters D _AVE : all the used roller diameters Roller average diameter [0011] Here, F _MAX : the maximum value of the roundness of all the rollers used D _AVE : the average diameter of all the rollers used According to this rolling bearing, Dimensional accuracy,
In particular, the maximum mutual difference rate for all roller diameters used and the maximum roundness rate for all rollers used are reduced, and skew is appropriately suppressed to extend the life. Can be planned. Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing an embodiment of a double-row spherical roller bearing as a rolling bearing according to the present invention. In FIG. 1, the double row spherical roller bearing includes an outer ring 1
, An inner ring 2, a plurality of rows of rollers 3 arranged between the outer ring 1 and the inner ring 2, and a retainer 4 for holding these rollers 3. Here, in this double row self-aligning roller bearing, since the roller 3 has a large contact angle α, the rolling speed at both ends of the roller 3 differs during the operation of the bearing. The present inventors installed a non-contact type sensor 5 on the end face of the roller 3 of the double-row self-aligning roller bearing since the state in which the roller rolls with a slanted sliding (roller skew) is likely to occur. Then, the movement of the roller 3 was measured by the sensor 5, and the skew situation was confirmed under various conditions depending on the difference in machining accuracy of the bearing. As a result, the present inventors have confirmed that the contact angle α, the roughness of the inner ring 2 and the outer ring 1, the lubrication conditions, and the like affect the skew situation. It has been discovered that the skew situation changes due to the difference in the dimensional accuracy of No. 3 and the bearing life differs. That is, as shown in FIG. 2, the roller 3 is a symmetric roller in which the center line CL of the rolling surface 3a is symmetrical.
The dimensional accuracy of the R shape of the rolling surface 3a shown in the middle, the dimensional accuracy of the shape of the chamfered 3b shown in the
In addition to the surface roughness of a, the dimensional accuracy of the length of the roller 3 indicated by, the roundness of the roller 3 indicated by, and the dimensional accuracy of the roller diameter of the largest diameter portion of the roller 3 indicated by, etc. exist. I do. The present inventors deliberately change the manufactured roller 3 with respect to the dimensional accuracy described above by adjusting the processing, thereby changing the skew situation and causing a difference in the bearing life. Was confirmed to occur.
However, even if the dimensional accuracy of these conditions was processed under the same conditions, it was found that there was variation in the skew situation, and further investigation of the cause revealed that there was a difference in the dimensional accuracy described above. . That is, with respect to the above dimensional accuracy, since the high processing accuracy is maintained due to the recent improvement of the performance and accuracy of the machine tool, a level that does not greatly change the skew state unless intentionally changed. Met.
On the other hand, with respect to the dimensional accuracy described above, a change in the skew state was confirmed by a dimensional error of a few μm in the investigation by the present inventors. Accordingly, the present inventors have determined that the maximum mutual difference ratio M (in the maximum diameter portion) defined by the following equation (1) for all the roller diameters of the rollers 3 used in regard to the above dimensional accuracy. The roller diameter (D in FIG. 3) is measured for all the rollers 3 used in the bearing, and the difference between the maximum roller diameter D _{MAX and} the minimum roller diameter D _MIN is divided by the average roller diameter D _AVE to obtain 1000. The maximum roundness ratio P (roundness of the roller 3 is used for bearings) defined by the following equation (2) for all the rollers 3 used is 1.0 or less. The roller 3 is processed so that the maximum value of the roundness F _MAX divided by the roller average diameter D _AVE and multiplied by 1000) is 0.3 or less, and the skew is suppressed. The service life was extended. To satisfy such conditions,
In order to machine the roller 3, it is necessary to perform ultra-precision machining using the current state-of-the-art processing technology, and to measure the dimensions of the roller 3, it is necessary to perform the current state-of-the-art ultra-precision measurement. [Equation 5] Here, D _MAX : the maximum value among all the rollers 3 used D _MIN : the minimum value among all the rollers 3 used D _AVE : used Average diameter of all rollers [0021] Here, F _MAX : the maximum value among the roundnesses of all the rollers 3 used D _AVE : the average diameter of the rollers of all the rollers 3 to be used The reason for limiting the numerical value of the maximum roundness ratio P to 1.0 or less and 0.3 or less will be described. The maximum mutual difference ratio M: 1.0 or less The inventors of the present invention have proposed a spherical roller bearing in which the roundness of the roller 3 is equal to or less than a predetermined level.
Was changed to change the skew situation, and the extent to which the maximum mutual difference ratio M affects the life of the bearing was investigated.
FIG. 4 shows the results of the investigation. Referring to FIG. 4, the maximum mutual difference ratio M is 1.
Exceeds 0, skew of the roller is increased, L ₁₀ life ratio (test life / rated fatigue life) It is understood that reduced. Here, L is a fatigue life of 90% reliability.
_The test life is defined as ₁₀ life, and the rated fatigue life of the rolling bearing specified in JIS B1518 is defined as the rated fatigue life.
Therefore, the maximum mutual difference ratio M is set to 1.0 or less. In order to obtain a more stable bearing life, the maximum mutual difference ratio M is desirably 0.5 or less. The maximum roundness ratio P: 0.3 or less The present inventors have developed a maximum sphericality ratio P in a self-aligning roller bearing in which the roller diameter difference of the rollers 3 used is adjusted to a certain level or less. Was changed to change the skew situation, and it was investigated how much the maximum roundness factor P affects the life of the bearing. FIG. 5 shows the results of the investigation. Referring to FIG. 5, when the maximum roundness ratio P is 0.
Exceeds 3, the skew of the roller is increased, L ₁₀ life ratio is understood that reduced. Therefore, the maximum roundness ratio P is set to 0.3 or less. In order to obtain a more stable bearing life, the maximum roundness ratio P is desirably 0.2 or less. The embodiment of the present invention has been described above, but the present invention is not limited to this, and various modifications can be made. For example, the rolling bearing to which the present invention is applied is not limited to a double-row self-aligning roller bearing, but may be a single-row self-aligning roller bearing. EXAMPLE A life test of a self-aligning roller bearing lubricated in a clean environment was performed under the following conditions 1 and 2, and the relationship between the life of the bearing and the maximum mutual difference ratio M and the life of the bearing were obtained. And the maximum roundness ratio P was confirmed. The sizes of the spherical roller bearings are different between the condition 1 and the condition 2. Life test condition 1: Nominal number: Spherical roller bearing 22211 Test machine name: NSK (Nippon Seiko Co., Ltd.), Spherical roller bearing life tester Test load: Radial load = 45000N (Pr / Cr =
0.38) Here, Pr: equivalent radial load, here equivalent to radial load Cr: Radial basic dynamic rated load Bearing rotation speed: 1500 rpm Lubricating oil: RO type, ISO VG68 Lubricating oil filter: 10 μm + 3 μm Life test condition 2 No .: Spherical roller bearing 22216 Test machine name: NSK (Nippon Seiko Co., Ltd.), Spherical roller bearing life tester Test load: Radial load = 45000N (Pr / Cr =
0.38) Bearing rotation speed: 1500 rpm Lubricating oil: RO type, ISO VG68 Lubricating oil filter: 10 μm + 3 μm As a life test method, ten co-specimen bearings were prepared under conditions 1 and 2 and each bearing was provided. A life test was performed. To determine the life, the test was interrupted when the vibration value of the bearing became twice the initial vibration value, and the presence or absence of flaking on the raceway surface was confirmed. Then, according to the Weibull function distribution, 10% of the ten co-sample
The bearing total rotation time to chestnut and problems occur: seeking (L ₁₀ life of 90% reliability fatigue life), which was used as a test life. In this life test, life tests of bearings having different sizes under the conditions 1 and 2 are performed, and even if the sizes are different, the maximum mutual difference ratio M and the maximum roundness ratio P indicate the life. It was confirmed that there was a correlation. Therefore, the result of the life test, divided by the nominal fatigue life of the rolling bearing shown the above-mentioned test lifetime JIS B1518, are indicated by L ₁₀ life ratio. The relationships and L ₁₀ life ratio and maximum relationship between circularity ratio P of the L ₁₀ life ratio and the maximum relative difference ratio M is a life test results of the self-aligning roller bearing 22211 conditions 1, Table 1 6 and 7 in which the results of Table 1 are plotted. [Table 1] Referring to Table 1, FIG. 6, and FIG. 7, Examples 1 to 9 in which the maximum mutual difference ratio M is 1.0 or less and the maximum roundness ratio P is 0.3 or less. in, L ₁₀ life ratio There are 11.6 at a minimum, it is understood that the life of the bearing becomes good. On the other hand, in Comparative Examples 1 and 2, the maximum roundness ratio P is 0.3 or less, but the maximum mutual difference ratio M is 1.
Greater than 0, the skew violently L ₁₀ life ratio becomes smaller, respectively 1.5,1.2. Comparative Example 3
Or in 5, the maximum relative difference ratio M is either 1.0, greater than 0.3 both maximum roundness factor P is, skew violently L ₁₀ life ratio respectively 2.1,
1.3 and 0.8 are small. As shown in FIGS. 6 and 7, in order to obtain a more stable bearing life, the maximum mutual difference ratio M is 0.5 or less and the maximum roundness ratio P is 0.2 or less. It is understood that it is desirable. Further, the self-aligning roller bearing 2221 under the condition 2 is used.
8 6 the relationship between the relationship and L ₁₀ life ratio and the maximum roundness ratio P of the L ₁₀ life ratio and the maximum relative difference ratio M is a life test results, obtained by plotting the results in Table 2 and Table 2, As shown in FIG. [Table 2] Referring to Table 2, FIG. 8, and FIG. 9, Examples 10 to 18 in which the maximum mutual difference ratio M is 1.0 or less and the maximum roundness ratio P is 0.3 or less. in, L ₁₀ life ratio There are 10.1 at a minimum, it is understood that the life of the bearing becomes good. On the other hand, in Comparative Examples 6 and 7, the maximum roundness factor P is either 0.3 or less, greater than 1.0 both maximum mutual difference ratio M, skew vigorously L ₁₀ life The ratios are as small as 1.4 and 1.2, respectively. In Comparative Examples 8 to 10, the maximum mutual difference ratio M was 1.0 or less, but the maximum roundness ratio P was 0.3 or less.
Greater than the skew violently L ₁₀ life ratio becomes smaller, respectively 2.1,1.1,0.7. As shown in FIGS. 8 and 9, in order to obtain a more stable bearing life, the maximum mutual difference ratio M is 0.5 or less and the maximum roundness ratio P is 0.2 or less. It is understood that it is desirable. As described above, according to the rolling bearing according to the first aspect of the present invention, the maximum mutual difference ratio M is 1.0 for all the roller diameters used. Below and for all the rollers used, the maximum roundness factor P
Is 0.3 or less, the dimensional accuracy of the manufactured roller,
In particular, the maximum mutual difference rate for all roller diameters used and the maximum roundness rate for all rollers used are reduced, thereby appropriately suppressing skew and extending service life. Can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view showing an embodiment of a double-row spherical roller bearing as a rolling bearing according to the present invention. FIG. 2 is a front view of a roller used in the double row spherical roller bearing of FIG. 1; FIG. 3 is a front view of rollers used in the double-row spherical roller bearing of FIG. 1; [4] In the self-aligning roller bearings aligned below a certain level the roundness of the roller to be used is a graph showing the relationship between L ₁₀ life ratio and the maximum relative difference ratio. [5] of the rollers used in self-aligning roller bearings aligned below a certain level the roller diameter relative difference is a graph showing the relationship between L ₁₀ life ratio and the maximum roundness factor. 6 is a graph showing the relationship between the life test results of the self-aligning roller bearing 22211 is L ₁₀ life ratio of condition 1 and the maximum relative difference ratio. 7 is a graph showing the relationship between L ₁₀ life ratio is life test results of the self-aligning roller bearing 22211 conditions 1 and maximum roundness factor. 8 is a graph showing the relationship between L ₁₀ life ratio is life test results of the self-aligning roller bearing 22216 Condition 2 and the maximum relative difference ratio. 9 is a graph showing the relationship between L ₁₀ life ratio is life test results of the self-aligning roller bearing 22216 conditions 2 and maximum roundness factor. [Description of Signs] 1 Outer ring 2 Inner ring 3 Roller 3a Rolling surface 3b Chamfer 4 Cage 5 Sensor

Claims (1)

Claims: 1. A rolling bearing comprising an inner ring, an outer ring, a plurality of rollers disposed between the inner ring and the outer ring, and a retainer for holding the rollers. The following (1) for all roller diameters
The maximum mutual difference ratio M defined by the equation is 1.0 or less, and
A rolling bearing, wherein the maximum roundness ratio P defined by the following equation (2) is 0.3 or less for all the rollers used. (Equation 1) Here, D _MAX : the maximum value among all the used roller diameters D _MIN : the minimum value among all the used roller diameters D _AVE : all the used roller diameters Average diameter [Equation 2] Here, F _MAX : the maximum value of the roundness of all the rollers used D _AVE : the average diameter of the rollers of all the rollers used