JP2007333161A - Manufacturing method of self-aligning roller bearing, and self-aligning roller bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method which acquires a structure for suppressing sufficiently friction and heat generation by skew of each spherical roller 3, 3. <P>SOLUTION: Processing conditions for forming an outer ring raceway 5 is determined as follows, and the outer ring raceway 5 is formed depending on the processing conditions. First of all, a range of a friction coefficient between the outer ring raceway 5 and the rolling face of each spherical roller 3, 3, capable of suppressing sufficiently friction and heat generation by skew is set. Then, a range of a load surface ratio at the height of an oil film thickness is set from the range of the friction coefficient and the oil film thickness anticipated from operation conditions. A processing condition for acquiring the surface shape having a three-dimensional load curve passing the set range is determined. Hereby, the friction coefficient of the outer ring raceway 5 is set surely within a desired range. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The self-aligning roller bearing according to the present invention is used in a state where it is incorporated in a rotation support portion of a roll or the like of various industrial machine devices such as a papermaking machine and a metal rolling mill in order to support a rotating shaft inside the housing, for example. To do.

  For example, in order to rotatably support a heavy shaft on the inside of a housing, a self-aligning roller bearing as described in, for example, Patent Documents 1 and 2 has been used. FIG. 1 shows an example of a conventional structure of such a self-aligning roller bearing. This self-aligning roller bearing is formed by rolling a plurality of spherical rollers 3 and 3 between an outer ring 1 and an inner ring 2 that are concentrically combined with each other. The pair of retainers 4 and 4 prevent separation of the plurality of spherical rollers 3 and 3. Each of these cages 4 and 4 is a so-called press cage formed by press-molding a metal plate.

  An outer ring raceway 5 that is a spherical concave surface having a single center is formed on the inner peripheral surface of the outer ring 1. Further, a pair of inner ring raceways 6 and 6 are formed on both sides of the outer peripheral surface of the inner ring 2 in the width direction (left and right direction in FIG. 1). The plurality of spherical rollers 3 and 3 have a symmetric shape (beer barrel shape) in which the maximum diameter portion is in the center portion of the axial length of each spherical roller 3 or 3, or the maximum diameter portion is pivoted from the center portion. Asymmetrically shifted in the direction, the outer ring raceway 5 and the pair of inner ring raceways 6 and 6 are divided into two rows, and a plurality of each row are provided to be freely rollable.

  For example, when the rotating shaft is supported inside the housing by the self-aligning roller bearing configured as described above, the outer ring 1 is fitted and fixed to the housing, and the inner ring 2 is fitted and fixed to the rotating shaft. When the inner ring 2 rotates together with the rotation shaft, the plurality of spherical rollers 3 and 3 roll to allow this rotation. When the shaft center of the housing and the shaft center of the rotating shaft do not match, the inner ring 2 is aligned inside the outer ring 1 (the center axis of the inner ring 2 is inclined with respect to the center axis of the outer ring 1). To compensate. In this case, since the outer ring raceway 5 is formed in a single spherical shape, the rolling of the plurality of spherical rollers 3 and 3 is smoothly performed even after the inconsistency compensation.

  In the case of the self-aligning roller bearing acting as described above, the width direction of each spherical roller 3, 3 between the outer ring raceway 5 and the rolling surface of each spherical roller 3, 3 during alignment (FIG. 1). Left and right). In the case of the above self-aligning roller bearing, the spherical rollers 3 and 3 are likely to be skewed. Therefore, in the case of the self-aligning roller bearing, heat generation and early separation are likely to occur at the contact portion between the outer ring raceway 5 and the spherical rollers 3 and 3. For this reason, as described in, for example, Patent Documents 3 to 6, techniques for suppressing heat generation and early separation that occur at the contact portion between the outer ring raceway 5 and the spherical rollers 3 and 3 have been conventionally known.

Of these, Patent Document 3 describes a technique for regulating the respective friction coefficients of the contact portions between the outer ring raceway or the inner ring raceway and the rolling surface of each spherical roller and suppressing the skew of each spherical roller. Yes. Further, Patent Document 4 describes a technique in which a mesh-like processed mesh that intersects the outer ring raceway is formed, and the surface roughness between the axial direction and the circumferential direction of the outer ring raceway is substantially constant. . Patent Document 5 describes a technique for regulating the center line roughness between the outer ring raceway and the inner ring raceway. Further, Patent Document 6 discloses an arithmetic average roughness (R _a1 , R _a2 ) between the axial direction and the circumferential direction of the outer ring raceway or the inner ring raceway, and a ratio (R _a1 / R _a2 ) between these arithmetic mean roughnesses. ) As well as the average depth (R _vk1 , R _vk2 ) of the projecting troughs of the surface roughness between the axial direction and the circumferential direction of the outer ring raceway or the inner ring raceway.

  Among the patent documents described above, the techniques described in Patent Documents 3 to 5 suppress the skew of each spherical roller, and generate heat at the contact portion between the outer ring raceway and the rolling surface of each spherical roller, or early. Reduces the occurrence of peeling. On the other hand, the technique described in Patent Document 6 described above restricts the surface properties of the outer ring raceway or the inner ring raceway so that a good oil reservoir exists on the surface, and these outer ring raceway or inner ring raceway and each spherical roller. The lubrication characteristics of the contact portion with the rolling surface of the roller are improved, and the occurrence of heat generation and early peeling at the contact portion is suppressed.

  In any of the above-described inventions, two-dimensional parameters are considered in order to regulate the surface properties of the raceway surface. In addition, among the above patent documents, the inventions described in Patent Documents 3 to 5 are intended to suppress friction and heat generation due to skew of each spherical roller. It is necessary to consider the coefficient of friction between the rolling surfaces of the rollers. In particular, as described in Patent Document 3, the friction coefficient between the outer ring raceway and the rolling surface of each spherical roller is determined from the friction coefficient between the inner ring raceway and the rolling surface of each spherical roller. Increasing the length is also important for preventing the skew of these spherical rollers. However, the friction coefficient needs to be a value at which the heat generated between the raceway surface and the rolling surface of each spherical roller does not exceed the allowable value. As described above, the friction coefficient that has an important influence on the skew of each spherical roller depends on the three-dimensional properties such as the height of the mountain existing on the surface of the raceway surface and the ratio of the mountain. In other words, the three-dimensional contact state between the raceway surface and the rolling surface of each spherical roller greatly affects the friction coefficient. For this reason, in the case of a structure in which the surface properties of the raceway surface are evaluated with two-dimensional parameters as in the inventions described in the above Patent Documents 3 to 5, the friction coefficient cannot always be controlled within a predetermined range. Absent.

JP-A-5-157116 Japanese Patent No. 3529191 Japanese Patent Publication No.57-61933 JP-A-2005-90615 JP 2005-30425 A JP 2004-353743 A

  The present invention has been invented to realize a manufacturing method capable of obtaining a structure capable of sufficiently suppressing friction and heat generation due to skew of each spherical roller in view of the circumstances as described above.

The self-aligning roller bearing that is the subject of the present invention includes an outer ring, an inner ring, and a plurality of spherical rollers, similarly to the conventional self-aligning roller bearing shown in FIG.
Among these, the outer ring forms an outer ring raceway having a spherical concave surface on the inner peripheral surface thereof.
Further, the inner ring forms a pair of inner ring raceways opposed to the outer ring raceway on the outer peripheral surface thereof.
Each of the spherical rollers is provided in two rows between the outer ring raceway and the inner ring raceways so as to be freely rotatable in each row.

In particular, in the manufacturing method of the self-aligning roller bearing of the present invention, the processing conditions for forming the outer ring raceway are determined in the following order, and the outer ring raceway is formed under the processing conditions.
(1) The lower limit of the friction coefficient between the outer ring raceway and the rolling surface of each spherical roller is set to a value larger than the friction coefficient between the inner ring raceway and the rolling surface of each spherical roller. The upper limit value is set to a value at which the heat generated between the outer ring raceway and the rolling surface of each spherical roller does not exceed the allowable value. Note that the “value at which the heat generation does not exceed the allowable value” is set so that seizure does not occur at an early stage in consideration of, for example, the operating conditions of the rotary support portion incorporating the self-aligning roller bearing.
(2) From the lower limit value and upper limit value of the friction coefficient, and the oil film thickness between the outer ring raceway and the rolling surface of each spherical roller predicted from the operating conditions, Set the range of the load area ratio. The “operating conditions” include, for example, the operating speed of a rotating support portion incorporating a self-aligning roller bearing, the load acting on the rotating support portion, the type of lubricating oil, the supply method and the supply amount.
(3) Determine the processing conditions for obtaining a surface texture that has a three-dimensional load curve that passes through the set range.

The relationship between the friction coefficient and the load area ratio (= load support ratio due to metal contact) at the height of the oil film thickness is estimated as follows.
Friction coefficient = (Load support ratio by metal contact) x (Friction coefficient of metal contact)
+ (Load support ratio by fluid lubrication) x (Friction coefficient of fluid lubrication) --- (A)
In addition, the relationship between "load support ratio due to metal contact" and "load support ratio due to fluid lubrication" is
(Load support ratio by fluid lubrication) = 100− (Load support ratio by metal contact) (%)
――― (B) Therefore, if the lower limit value and the upper limit value of the friction coefficient are set, and the values of “friction coefficient of metal contact” and “friction coefficient of fluid lubrication” are known, both of the above formulas (A) and (B) It is possible to derive the range of the “load support ratio by metal contact” (that is, the load area ratio at the height of the oil film thickness).

The three-dimensional load curve is defined as follows because there is no clear definition in Japanese Industrial Standard (JIS). FIG. 2 shows a two-dimensional load curve based on a cross-sectional curve described in International Standard: ISO 13565-2. This two-dimensional load curve is expanded to three dimensions by the following method.
First, the height z (x _i , y _j ) at each point (x _i , y _j ) on the measurement surface is obtained, and the load curve of the entire measurement surface is obtained. The three-dimensional load curve thus obtained is shown in FIG. Then, based on the three-dimensional load curve shown in FIG. 3, S _r1 , S _r , S _r1 , S _r , M _r1 , M _r2 (load length ratio of the core part), etc. of the two-dimensional load curve defined in ISO 13565 Calculate _r2 etc. X _i is the i-th X-direction coordinate, and y _j is the j-th y-direction coordinate. The meanings of the symbols shown in FIG. 3 are as follows.
S _k : Level difference of the core part S _pk : Height of the protruding peak part S _vk : Depth of the protruding valley part S _r1 : Load area ratio of the core part on the peak part side S _r2 : Load on the core part on the valley part side Area ratio The above-mentioned parameters can be automatically calculated by analysis software “Tarimap” manufactured by Taylor Hobson.

Further, when the present invention is implemented, preferably, as described in claim 2, the load area ratio at the intersection of the three-dimensional load curve and the height of the oil film thickness is set to the peak side of the three-dimensional load curve. It is assumed that the load area ratio (S _r1 ) or less of the core portion is less.
In order to obtain an outer ring raceway having the above-described properties, preferably, as described in claim 3, the outer ring raceway is processed by super finishing after grinding.
Further, as specific numerical values of the present invention, for example, as described in claim 4, the oil film thickness between the outer ring raceway and the rolling surface of each spherical roller predicted from the operating conditions is 0.5 μm. The range of the load area ratio at the height of the oil film thickness is set to 11.8 to 21.7%.
Further, in the self-aligning roller bearing manufactured by the above-described manufacturing methods, as described in claim 5, the surface roughness in the axial direction of the outer ring raceway and the surface roughness in the circumferential direction should be substantially the same. Is preferred.

In the case of the present invention configured as described above, the friction coefficient between the outer ring raceway and the rolling surface of each spherical roller is regulated in consideration of the three-dimensional properties. Friction and heat generation due to the skew can be sufficiently suppressed.
That is, in the case of the present invention, as apparent from the equation (A), the range of the load support ratio by the metal contact is determined so that the friction coefficient is within a predetermined range, and the outer ring raceway is set within this range. The surface texture has a three-dimensional load curve that passes through. For this reason, the friction coefficient can be reliably regulated within a predetermined range, and friction and heat generation due to skew of the spherical rollers can be sufficiently suppressed. As a result, the life of the self-aligning roller bearing can be extended.

Further, as described in claim 2, the load area ratio at the intersection of the three-dimensional load curve and the height of the oil film thickness is defined as the load area ratio (S _r1 of the core portion on the mountain side of the three-dimensional load curve. ) If it is as follows, the friction coefficient is less likely to change even if the oil film thickness varies. That is, the three-dimensional load curve is generally (for example, in the case of a ground surface or a superfinished surface), as apparent from FIG. 3 described above, in the region where the load area ratio is closer to 0 than S _r1 , It is known that the rate of change in height with respect to the change in the load area ratio is larger than (the load area ratio is S _{r1 to} S _r2 ). Therefore, in a region where the load area ratio is closer to 0 than S _r1 , even if the height of the oil film thickness changes greatly, it is difficult to deviate from the predetermined load area ratio range. That is, the coefficient of friction is difficult to change. For this reason, in the case of the invention described in claim 2, friction and heat generation due to skew can be suppressed even under operating conditions in which the oil film thickness tends to fluctuate.

  Furthermore, in the self-aligning roller bearing manufactured by the above-described manufacturing methods, as described in claim 5, if the surface roughness in the axial direction of the outer ring raceway and the surface roughness in the circumferential direction are substantially the same, Thus, the effect of suppressing skew can be enhanced, and the life of the self-aligning roller bearing can be further extended.

[First example of embodiment]
A first example of an embodiment of the present invention corresponding to claim 1 will be described with reference to FIGS. Note that FIG. 4 and FIGS. 5 to 7 described later show a part corresponding to a part (upper left) of the three-dimensional load curve shown in FIG. 3 described above. In addition, the feature of the present invention is that the surface property of the outer ring raceway 5 is three-dimensionally so as to surely regulate the friction coefficient between the outer ring raceway 5 and the rolling surfaces of the spherical rollers 3 and 3 within a predetermined range. In consideration, the outer ring raceway 5 is processed. Since the structure and operation of the self-aligning roller bearing itself are the same as those of the conventional structure shown in FIG. 1 described above, the overlapping description will be omitted or simplified, and the following description will focus on the features of this example.

In the case of this example, the processing conditions for forming the outer ring raceway 5 are determined in the following order, and the outer ring raceway 5 is formed under the processing conditions.
(1) The lower limit of the friction coefficient between the outer ring raceway 5 and the rolling surfaces of the spherical rollers 3 and 3 is defined as the friction between the inner ring raceway 6 and the rolling surfaces of the spherical rollers 3 and 3. The upper limit value is set to a value larger than the coefficient so that the heat generated between the outer ring raceway 5 and the rolling surfaces of the spherical rollers 3 and 3 does not exceed the allowable value.
(2) From the lower limit value and the upper limit value of the friction coefficient, and the oil film thickness between the outer ring raceway 5 and the rolling surfaces of the spherical rollers 3 and 3 predicted from the operating conditions, The range (S _{rmin to} S _rmax ) of the load area ratio at the height (broken line in FIG. 4) is set.
(3) As shown in FIG. 4, the processing conditions for obtaining a surface property having a three-dimensional load curve passing through the set range are determined.

  That is, in the case of this example, first, a target friction coefficient range is determined, and a three-dimensional load curve indicated by a solid line in FIG. 4 that satisfies this friction coefficient range is obtained. Then, processing conditions that satisfy this three-dimensional load curve are determined by experiments or the like. For example, the processing of the outer ring raceway 5 is preferably performed by superfinishing after grinding. However, the shape and grain size of the abrasive grains, the rotational speed of the outer ring, and the grindstone are obtained so as to obtain the surface properties having the three-dimensional load curve. Adjust the machining conditions such as the rocking speed. For example, as a super-finishing grindstone, a CBN abrasive grain using a vitrified binder is used, and the rotational speed of the outer ring at the time of super-finishing is lower than the rotational speed at the time of roughing. When the machining conditions are determined, the friction coefficient between the outer ring raceway 5 and the rolling surfaces of the spherical rollers 3 and 3 is set to the above target range, that is, “inner ring raceway 6 and each spherical surface. "Friction coefficient between the rolling surfaces of the rollers 3 and 3" is larger than "a value at which the heat generated between the outer ring raceway 5 and the rolling surfaces of the spherical rollers 3 and 3 does not exceed the allowable value". Can be reliably regulated to the range. As a result, friction and heat generation due to skew can be suppressed. If the surface roughness in the axial direction of the outer ring raceway 5 and the surface roughness in the circumferential direction are substantially the same when processing under the above-described processing conditions, the effect of suppressing skew can be enhanced, and automatic adjustment is performed. Longer life of the core roller bearing can be achieved.

[Second Example of Embodiment]
A second example of an embodiment of the present invention corresponding to claim 2 will be described with reference to FIGS. In the case of this example, in addition to the conditions of the first example described above, the load area ratio S _ra at the intersection point a between the three-dimensional load curve and the height of the oil film thickness (broken line in FIG. 5) is _expressed as the three-dimensional load. The load area ratio (S _r1 ) or less of the core portion on the peak portion side of the curve is set. That is, in the case of this example, the S _ra is the outer ring raceway predicted from the lower and upper limits of the friction coefficient between the outer ring raceway 5 and the rolling surfaces of the spherical rollers 3 and 3, and the operating conditions. 5 and within the range (S _{rmin to} S _rmax ) of the load area ratio at the height of the oil film thickness set from the oil film thickness between the spherical rollers 3 and the rolling surfaces of the spherical rollers 3 and 3 It is smaller than S _r1 . If the outer ring raceway 5 is processed into a surface texture having a three-dimensional load curve that satisfies such conditions, friction and heat generation due to skew can be suppressed even under operating conditions in which the oil film thickness is likely to vary.

That is, the three-dimensional load curve of the present embodiment, as apparent from FIG. 5, the load area ratio is closer to 0 than S _r1 area equivalent area (load area ratio S _r1 to S _r2: see FIG. 3) The change rate (slope) of the height with respect to the change of the load area ratio is larger. Therefore, by making the load area ratio S _ra at the intersection point a in a region closer to 0 than S _r1 having a large slope, the intersection point a is within the range of S _{rmin to} S _rmax as shown in FIG. It is possible to change relatively large up and down. For this reason, even if the height of the oil film thickness (intersection point a) changes greatly, it is difficult to deviate from the predetermined load area ratio range (S _{rmin to} S _rmax ) (that is, the friction coefficient is difficult to change). For this reason, in this example, friction and heat generation due to skew can be suppressed even under operating conditions in which the oil film thickness is likely to vary.
Other structures and operations are the same as those of the first example of the above-described embodiment.

An embodiment corresponding to claim 1 will be described.
In the case of this embodiment, first, the friction coefficient of metal contact between the raceway surface and each spherical roller is set to 0.1, and the friction coefficient of fluid lubrication is set to 0.049. The coefficient of friction between the inner ring raceway and the rolling surface of each spherical roller is set to 0.054 or less. Furthermore, the value of the friction coefficient that does not exceed the allowable value of heat generation between the outer ring raceway and the rolling surfaces of these spherical rollers is set to 0.06. For this reason, in the case of a present Example, the friction coefficient between the target outer ring track and the rolling surface of each spherical roller shall be 0.055-0.06. In the case of this embodiment, the oil film thickness expected from the operating conditions is 0.5 μm.

By substituting the above values into the following equation, the load area ratio at the height of the oil film thickness, that is, the range of the load support ratio x due to metal contact is obtained.
Friction coefficient = (Load support ratio by metal contact) x (Friction coefficient of metal contact)
+ (Load support ratio by fluid lubrication) × (Friction coefficient of fluid lubrication) −−− (A) 0.055−0.06 = x × 0.1 + (1−x) × 0.049 {(B) From the expression}
x = 0.118 to 0.217 = 11.8 to 21.7%
As a result, S _rmin is 11.8% and S _rmax is 21.7%.
As a three-dimensional load curve that satisfies such a range, for example, a three-dimensional load curve as shown in FIG. 6 is obtained.
The outer ring raceway has a three-dimensional load curve obtained as described above (that is, a three-dimensional load curve having a height of 0.5 μm and a load area ratio ranging from 11.8 to 21.7%). For example, after grinding and finishing by superfinishing, the friction coefficient between the outer ring raceway and the rolling surface of each spherical roller is within the range of 0.055 to 0.06, which is the above target value. It can be regulated reliably.

An embodiment corresponding to claim 2 will be described.
In the case of the present embodiment, in addition to the conditions of the first embodiment described above, as shown in FIG. 7, the load area ratio S _ra at the intersection point a between the three-dimensional load curve and the height of the oil film thickness is represented by this three-dimensional The load area ratio S _r1 or less of the core portion on the peak side of the load curve is set. The three-dimensional load curve thus obtained (that is, the height is 0.5 μm, the load area ratio passes through the range of 11.8 to 21.7%, and the three-dimensional load curve and the height of the oil film thickness are If the outer ring raceway is finished by, for example, superfinishing after grinding, the outer ring raceway and each spherical roller have a three-dimensional load curve that is equal to or less than the load area ratio of the core portion on the mountain side. The coefficient of friction with the rolling surface can be reliably regulated within the range of 0.055 to 0.06, which is the above target value. Further, even under operating conditions in which the oil film thickness is likely to fluctuate, friction and heat generation due to skew can be suppressed.

FIG. 2 is a half sectional view showing an example of a self-aligning roller bearing that is a subject of the present invention. The figure which shows the two-dimensional load curve by the cross-sectional curve of ISO 13565-2 description. The figure which shows what expanded the two-dimensional load curve to three dimensions. The figure which shows a part of three-dimensional load curve which satisfy | fills the requirements of Claim 1. The figure which shows a part of three-dimensional load curve which satisfy | fills the requirements of Claim 2. The figure which shows a part of three-dimensional load curve of Example 1 corresponding to Claim 1. The figure which shows a part of three-dimensional load curve of Example 2 corresponding to Claim 2.

Explanation of symbols

1 Outer ring 2 Inner ring 3 Spherical roller 4 Cage 5 Outer ring raceway 6 Inner ring raceway

Claims (5)

An outer ring raceway which is a spherical concave surface, an outer ring formed on the inner peripheral surface thereof, a pair of inner ring races opposed to the outer ring raceway, an inner ring formed on the outer peripheral surface thereof, and between the outer ring raceway and the inner ring raceway. A method of manufacturing a self-aligning roller bearing having spherical rollers provided so as to be capable of rolling plurally in two rows in two rows, wherein the processing conditions for forming the outer ring raceway are as follows: A method of manufacturing a self-aligning roller bearing in which the outer ring raceway is formed under the processing conditions determined in the following order.
(1) The lower limit of the friction coefficient between the outer ring raceway and the rolling surface of each spherical roller is set to a value larger than the friction coefficient between the inner ring raceway and the rolling surface of each spherical roller. The upper limit value is set to a value at which the heat generated between the outer ring raceway and the rolling surface of each spherical roller does not exceed the allowable value.
(2) From the lower limit value and upper limit value of the friction coefficient, and the oil film thickness between the outer ring raceway and the rolling surface of each spherical roller predicted from the operating conditions, Set the range of the load area ratio.
(3) Determine the processing conditions for obtaining a surface texture that has a three-dimensional load curve that passes through this set range.   The self-aligning roller according to claim 1, wherein the load area ratio at the intersection of the three-dimensional load curve and the height of the oil film thickness is equal to or less than the load area ratio of the core portion on the mountain side of the three-dimensional load curve. Manufacturing method of bearing.   The method for manufacturing a self-aligning roller bearing according to claim 1 or 2, wherein the outer ring raceway is processed by superfinishing after grinding.   The oil film thickness between the outer ring raceway and the rolling surface of each spherical roller predicted from the operating conditions is 0.5 μm, and the range of the load area ratio at the height of this oil film thickness is 11.8 to 21.21. The manufacturing method of the self-aligning roller bearing described in any one of Claims 1-3 set to 7%. A self-aligning roller bearing manufactured by the method of manufacturing a self-aligning roller bearing according to any one of claims 1 to 4, wherein the surface roughness in the axial direction of the outer ring raceway and the surface in the circumferential direction are obtained. Spherical roller bearings with almost the same roughness.

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