JP2017180832A - Double-row self-aligning roller bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a double-row self-aligning roller bearing which is advantageously used for receiving different loads, axial load and radial load, on each of rollers of double rows aligned in an axial direction, and which can sufficiently maximize a load capacity of the rollers of the rows receiving the axial load by having a large contact angle between the rollers of both rows receiving the axial load.SOLUTION: A double-row self-aligning roller bearing 1 includes an inner ring 2 and an outer ring 3, and double-row rollers 4, 5 therebetween aligned in two rows in a bearing width direction. A raceway surface 3a of the outer ring 3 is in a spherical shape, and an outer surface of the double-row rollers 4, 5 forms a cross-sectional shape along the raceway surface 3a of the outer ring 3. The double-row rollers 4, 5 have different length L1, L2. A contact angle θ2 of the longer roller 5 is made larger than a contact angle θ1 of the smaller roller 4. A center position Q of a center rib 8 in a bearing width direction is shifted toward the longer roller 5 from a position on point P in a bearing width direction where action lines S1, S2 intersect to form contact angles θ1, θ2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a double-row self-aligning roller bearing applied to an application in which an uneven load is applied to two rows of rollers arranged in the bearing width direction, for example, a bearing that supports a main shaft of a wind power generator or an industrial machine. .

  In addition to the radial load caused by the weight of the blade and the rotor head, an axial load caused by wind force acts on the bearing that supports the main shaft of the wind power generator. When the main shaft supporting bearing is a double-row self-aligning roller bearing 41 as shown in FIG. 10, of the two rows of rollers 44 and 45 interposed between the inner ring 42 and the outer ring 43, the axial load Fa is mainly used. Only one row of rollers 45 on the rear side receives the axial load Fa. That is, one row of rollers 45 receives both a radial load and an axial load, while the other row of rollers 44 receives only a radial load. For this reason, the roller 45 in the row receiving the axial load has a larger contact surface pressure than the roller 44 in the row receiving only the radial load, and the surface damage and wear of the rolling surface of the roller 45 and the raceway surface 43a of the outer ring 43 are increased. Is likely to occur and the rolling life is short. Therefore, the actual life of the entire bearing is determined by the rolling life of the row of rollers 45 that receive the axial load.

  To solve the above problem, the lengths L1 and L2 of the two rows of rollers 54 and 55 interposed between the inner ring 52 and the outer ring 53 are made different from each other as in the double row self-aligning roller bearing 51 shown in FIG. Thus, it has been proposed that the load capacity of the rollers 55 in the row that receives the axial load be larger than the load capacity of the rollers 54 in the row that hardly receive the axial load (Patent Document 1). By setting the roller lengths L1 and L2 so that the load capacities of the rollers 54 and 55 in each row become appropriate, the rolling life of the rollers 54 and 55 in each row becomes substantially the same, and the actual bearing as a whole. Lifespan can be improved.

  Further, like the double-row self-aligning roller bearing 61 shown in FIG. 12, the contact angles θ1 and θ2 of the two rows of rollers 64 and 65 interposed between the inner ring 62 and the outer ring 63 are made different from each other, so that the contact angle θ2 A proposal has been made that a large axial load can be received by the roller 65 having a large diameter (Patent Document 2). By setting the contact angles θ1 and θ2 so that the load capacities of the rollers 64 and 65 in each row become appropriate, the rolling lives of the rollers 64 and 65 in each row become substantially the same, and the actual life of the entire bearing Can be improved.

International Publication No. 2005/050038 Pamphlet US 2014/0112607

  As described above, the contact angles θ1, θ2 of the two rows of rollers 64, 65 can be made different from each other by making the lengths L1, L2 of the two rows of rollers 54, 55 different from each other as shown in FIG. Also by making them different from each other, it is possible to increase the load capacity of the rollers 55 and 65 in the row receiving the axial load, thereby improving the actual life of the entire bearing. However, because there is a limitation on the dimensional standard (ISO standard; JIS B 1512) of the bearing, the load capacity of the rollers 55 and 65 of the row subjected to the axial load is adequate by using only one of the above two methods. It is difficult to increase to a reasonable value. That is, since the inner diameter, the outer diameter, and the bearing width are determined with respect to the nominal number according to the dimensional standard, if the length L2 of the roller 55 in the row receiving the axial load in FIG. The standard value is exceeded. If the contact angle θ2 of the roller 65 in the row receiving the axial load in FIG. 12 is excessively increased, the inner diameter d exceeds the standard value.

  Therefore, in order to equalize the contact surface pressure of the row receiving the axial load and the row receiving only the radial load without causing the dimensions of each part to deviate from the dimensional standard of the bearing, the method of making the lengths of the two rows of rollers different from each other An attempt was made to combine the contact angle of the two rows of rollers with different methods. In that case, it is important to increase the contact angle of the rollers in the row receiving the axial load, and to sufficiently increase the load capacity of the rollers.

  The object of the present invention is suitable for use in applications in which axial loads and radial loads are applied, and loads having different sizes act on two rows of rollers arranged in the axial direction. In order to make it sufficiently large, it is an object of the present invention to provide a double row self-aligning roller bearing capable of taking a large contact angle of a row roller subjected to an axial load.

The double-row self-aligning roller bearing according to the present invention has two rows of rollers arranged in the bearing width direction between the inner ring and the outer ring, the raceway surface of the outer ring is spherical, and the two-row roller Is a double row self-aligning roller bearing whose outer peripheral surface has a cross-sectional shape along the raceway surface of the outer ring,
The two rows of rollers have different lengths, and the contact angle of the long roller is greater than the contact angle of the short roller, and the portion between the two rows of rollers on the outer peripheral surface of the inner ring There is a middle brim, and the center position of the middle brim in the bearing width direction is closer to the longer roller side than the position in the bearing width direction at the point where the action lines forming the contact angles of both rows intersect each other. It is characterized by deviation.

  According to this configuration, by making the lengths of the two rows of rollers different from each other, a roller having a long length has a larger load capacity than a roller having a short length. Further, since the contact angle of the long roller is larger than that of the short roller, the long roller can bear a large axial load. By making the contact angle of the long roller larger than the contact angle of the short roller, the contact angle of the short roller is reduced and the radial load capacity of the short roller is reduced. improves.

  When this double row spherical roller bearing is used under conditions where axial load and radial load are applied, a roller with a long length and a large contact angle bears almost all of the axial load and part of the radial load. The remainder of the radial load is borne by rollers with short and small contact angles. By sharing the axial load and the radial load between the two rows of rollers at such a sharing ratio, the contact surface pressure of the rollers in both rows can be made uniform. As a result, a large load capacity can be ensured in the entire bearing, and the substantial life of the entire bearing can be improved.

  By shifting the center position in the bearing width direction of the middle collar toward the roller with a longer length than the position in the bearing width direction at the point where the lines of action forming the contact angles of both rows intersect each other, the length is shortened. The ratio of the contact angle of the long roller to the contact angle of the roller can be increased. Thereby, it becomes possible to bear a larger axial load with a roller having a long length and a large contact angle.

In the present invention, the ratio of the contact angle of the short roller to the contact angle of the long roller is preferably in the range of 1: 2 to 1: 4.
Expected when multiple double-row spherical roller bearings with different contact angle ratios for both rows of rollers are used, and each double-row spherical roller bearing is used as a spindle support bearing for a wind turbine generator. The contact surface pressure of the rollers in both rows at that time was analyzed with an axial load and a radial load. As a result, it was found that when the contact angle ratio is in the range of 1: 2 to 1: 4, the contact pressures of the rollers in both rows are sufficiently equalized. The optimum contact angle ratio is 1: 3.

This double row self-aligning roller bearing is suitable for supporting the main shaft of the wind power generator.
A radial load due to the weight of the blade and the rotor head and an axial load due to wind force are applied to the double row spherical roller bearing that supports the main shaft of the wind power generator. Of the two rows of rollers arranged in the bearing width direction, one roller row receives both a radial load and an axial load, and the other row roller receives almost only a radial load. In that case, the roller in the row receiving the axial load is a roller having a long length and a large contact angle, and the roller in a row receiving only the radial load is a roller having a short length and a small contact angle. The contact surface pressure of the rows of rollers can be made substantially uniform.

Each of the rows of rollers is provided with a cage, and each cage has an annular ring portion that guides an axially inner end face of each row of rollers, an axially extending from the annular portion, and a circular shape. A plurality of pillars provided at intervals defined along the circumferential direction, pockets for holding the rollers are provided between the pillars, and one of the cages for holding the long rollers is The outer diameter surface of the column part has an inclination angle inclined inward in the radial direction from the base end side toward the tip end side,
Each of the rollers has a DLC film on the roller rolling surface, and a crowning at an end of the roller rolling surface,
The inner ring is provided between the two rows of rollers on the outer peripheral surface of the inner ring and guides the two rows of rollers, and the end surface on the outer side in the axial direction of each row of rollers provided on both ends of the outer peripheral surface. The inner ring may be provided with a slot into which the long roller is inserted into the bearing in the small brim facing the axially outer end surface of the long roller. .
The predetermined interval is an interval arbitrarily determined by design or the like, and is determined by determining an appropriate interval by, for example, one or both of testing and simulation.
The DLC is an abbreviation for Diamond-like Carbon.

According to this structure, since each roller has a DLC film on the roller rolling surface, it is possible to improve wear resistance. As a result, the roller rolling surfaces and the inner and outer raceways are less likely to be worn than those without the DLC coating. Further, since the crowning is provided at the end of the roller rolling surface, the edge stress can be reduced.
One cage that holds the long roller has an inclination angle in which the outer diameter surface of the column portion inclines radially inward from the proximal end side toward the distal end side, so that the pocket surface of the cage has the maximum diameter of the roller. Can hold a position. Thereby, the posture stability of the long roller is not impaired, and the long roller can be easily assembled. The inner ring is provided with a slot for inserting the long roller into the bearing in the small collar facing the axially outer end face of the long roller among the individual collars, so that it is possible to further improve the ease of assembling the long roller. .

  The double-row self-aligning roller bearing according to the present invention has two rows of rollers arranged in the bearing width direction between the inner ring and the outer ring, the raceway surface of the outer ring is spherical, and the two-row roller Is a cross-sectional shape in which the outer peripheral surface is along the raceway surface of the outer ring, and the two rows of rollers are different in length from each other, and the contact angle of the longer roller is longer than the contact angle of the shorter roller The middle collar is present at the portion between the two rows of rollers on the outer peripheral surface of the inner ring, and the center position of the middle collar in the bearing width direction is such that the lines of action forming the contact angles of both rows intersect each other. Because it is shifted to the longer roller side than the position in the bearing width direction, it receives an axial load and a radial load, and loads with different sizes act on two rows of rollers arranged in the axial direction. Suitable for use, sufficient load capacity of row rollers subjected to axial load To listen, it is possible to increase the contact angle of the rollers of the column for receiving an axial load.

It is sectional drawing of the double row self-aligning roller bearing concerning one Embodiment of this invention. It is explanatory drawing of an asymmetrical roller. It is a graph which shows the distribution analysis result of the contact surface pressure of the roller of the front side when the combined load of an axial load and a radial load is applied to the same double row spherical roller bearing and the conventional double row spherical roller bearing, respectively. . It is a graph which shows the distribution analysis result of the contact surface pressure of the roller of the rear side when the combined load of an axial load and a radial load is applied to the same double row spherical roller bearing and the conventional double row spherical roller bearing, respectively. . Fig. 4 shows the distribution analysis results of the contact pressure of the roller on the front side when a composite load of axial load and radial load is applied to multiple types of double row spherical roller bearings with different contact angle ratios for both rows of rollers. It is a graph. Fig. 5 shows the distribution analysis results of the contact pressure of the roller on the rear side when a composite load of axial load and radial load is applied to multiple types of double row spherical roller bearings with different contact angle ratios for both rows of rollers. It is a graph. It is the figure which illustrated the ratio of the roller length with respect to a bearing width on the same drawing about several conventional double row self-aligning roller bearings. It is the perspective view which notched and represented a part of example of the spindle support apparatus of the wind power generator. It is a fracture side view of the spindle support device. It is sectional drawing of the conventional common double row self-aligning roller bearing. It is sectional drawing of the double row self-aligning roller bearing of the 1st proposal example. It is sectional drawing of the double row self-aligning roller bearing of the 2nd proposal example. It is sectional drawing of the double row self-aligning roller bearing which concerns on other embodiment of this invention. It is an expanded sectional view which expands and shows a part of the same double row self-aligning roller bearing. It is an expanded sectional view which shows the DLC film etc. of the roller of the same double row self-aligning roller bearing. It is an expanded sectional view which shows the insertion groove | channel etc. of the inner ring | wheel of the double row self-aligning roller bearing. It is the end elevation which looked at the slot of the inner ring from the axial direction. It is sectional drawing of the double row self-aligning roller bearing which concerns on other embodiment of this invention.

An embodiment of the present invention will be described with reference to FIG.
This double-row self-aligning roller bearing 1 has two rows of left and right rollers 4 and 5 arranged in the bearing width direction between an inner ring 2 and an outer ring 3. The raceway surface 3 a of the outer ring 3 has a spherical shape, and the rollers 4 and 5 in each of the left and right rows have a cross-sectional shape along the raceway surface 3 a of the outer ring 3. In other words, the outer peripheral surfaces of the rollers 4 and 5 are rotating curved surfaces obtained by rotating an arc along the raceway surface 3a of the outer ring 3 around the center lines C1 and C2. The inner ring 2 is formed with double-row raceway surfaces 2a and 2b having a cross-sectional shape along the outer peripheral surfaces of the rollers 4 and 5 in the left and right rows. At both ends of the outer peripheral surface of the inner ring 2, collars (small collars) 6 and 7 are provided, respectively. An intermediate collar 8 is provided at the center of the outer peripheral surface of the inner ring 2, that is, between the left row roller 4 and the right row roller 5.

As shown exaggeratedly in FIG. 2, the left and right rollers 4 and 5 are asymmetrical rollers in which the positions of the maximum diameters D1 _max and D2 _max deviate from the center A1 and A2 of the roller length. The position of the maximum diameter D1 _max of the roller 4 in the left row is on the right side of the center A1 of the roller length, and the position of the maximum diameter D2 _max of the roller 5 in the right row is on the left side of the center A2 of the roller length. Induced thrust loads are generated in the rollers 4 and 5 in the left and right rows of such asymmetric rollers. In order to receive this induced thrust load, the middle collar 8 of the inner ring 2 is provided. The combination of the asymmetrical rollers 4 and 5 and the middle collar 8 guides the rollers 4 and 5 at the three locations of the inner ring 2, the outer ring 3 and the middle collar 8, so that the guidance accuracy is good.

As shown in FIG. 1, the roller 4 in the left row and the roller 5 in the right row have the same maximum diameters D1 _max and D2 _{max and} different lengths L1 and L2 along the center lines C1 and C2. . The length L2 of the long roller 5 is 39% or more of the bearing width B.

  Further, the contact angle θ2 of the roller 5 having a long length is larger than the contact angle θ1 of the roller 4 having a short length. The ratio of the contact angle θ1 of the short roller 4 to the contact angle θ2 of the long roller 5 is set in the range of 1: 2 to 1: 4. The most preferable ratio of the contact angles θ1 and θ2 is 1: 3. The reason will be described later. Specifically, the range of the contact angle θ1 is, for example, 5 ° to 7 °, and the range of the contact angle θ2 is, for example, 14 ° to 16 °.

  The position in the bearing width direction at the point P where the action lines S1 and S2 forming the contact angles θ1 and θ2 of both rows intersect with each other is closer to the side of the roller 4 that is shorter than the center position Q in the bearing width direction of the middle collar 8. Is shifted by a distance K. Thereby, the contact angle θ2 of the long roller 5 can be increased without making the long roller 5 longer than necessary. The action lines S1 and S2 are lines on which a combined force of forces acting on the contact portions between the rollers 4 and 5 and the inner ring 2 and the outer ring 3 acts. A point P where the action lines S1 and S2 intersect with each other is located on the bearing center axis O.

  The rollers 4 and 5 in the left and right rows are respectively held by cages 10L and 10R. In the left row retainer 10 </ b> L, a plurality of column portions 12 extend to the left side from the annular portion 11, and the left row rollers 4 are held in pockets between these column portions 12. In the right row retainer 10 </ b> R, a plurality of column portions 12 extend to the right side from the annular portion 11, and the right row rollers 5 are held in pockets between the column portions 12.

  The double-row self-aligning roller bearing 1 having this configuration is used as a main shaft support bearing of a wind power generator, for example, receiving an axial load and a radial load, and loads having different sizes acting on the left and right roller rows. In that case, the double row self-aligning roller bearing 1 is installed so that the left row roller 4 is located on the side closer to the swirl blade (front side) and the right row roller 5 is located on the far side (rear side). To do. Accordingly, the roller 5 in the right row having a long length L2 and a large contact angle θ2 bears almost all of the axial load and a part of the radial load, and the left row has a short length L1 and a small contact angle θ1. Roller 4 bears the remainder of the radial load.

  By appropriately setting the lengths L1 and L2 and the contact angles θ1 and θ2 of the rollers 4 and 5, it is possible to share the load at a ratio corresponding to the load capacity of the rollers 4 and 5 in the left and right rows. As a result, the surface pressures of the rollers 4 and 5 in the left and right rows are equalized. As a result, a large load capacity can be ensured in the entire bearing, and the substantial life of the entire bearing can be improved.

  An axial load assumed when the conventional double-row spherical roller bearing 41 shown in FIG. 10 and the double-row spherical roller bearing 1 of the present invention shown in FIG. 1 are used as main shaft support bearings of a wind turbine generator. The contact surface pressure of the left and right rows of rollers at that time was analyzed using a combined load of the load and radial load. 3 shows the contact surface pressure distribution of the rollers 44, 4 in the front side, that is, the left row, and FIG. 4 shows the analysis result of the contact surface pressure distribution of the rollers 45, 5 in the rear side, that is, the right row.

  The following can be understood from FIGS. The conventional product shown in FIG. 10 has a small contact surface pressure on the front side and a large contact surface pressure on the rear side, and the load load is not uniform between the front side and the rear side. On the other hand, in the contact angle change product of FIG. 1, the contact surface pressure is generated on the entire roller on the front side, so that the maximum value of the contact surface pressure on the rear side is lowered and the contact surface pressure difference between both rows is small. Are equalized.

  Also, three types of double-row self-aligning roller bearings having different ratios of the contact angle θ1 of the left row roller 4 and the contact angle θ2 of the right row roller 5 are prepared. The contact surface pressure was analyzed. FIG. 5 shows a contact surface pressure distribution analysis result of the roller 4 in the front side, that is, the left row, and FIG. 6 shows a contact surface pressure distribution analysis result of the roller 5 in the rear side, that is, the right row. A contact angle ratio of 1: 1 is a conventional product, and contact angle ratios of 1: 2 and 1: 3 are contact angle change products of the present invention.

  The following can be understood from FIGS. Comparing the contact surface pressure distribution analysis results for each contact angle ratio, the contact surface pressure ratio is 1: 3, and the contact surface pressure is most even on the front side and the rear side. The contact angle ratio of 1: 2 is not equalized compared to the contact angle ratio of 1: 3, but it is sufficiently equalized compared to the contact angle ratio of 1: 1. Has been. As can be seen from FIG. 1, when the contact angle θ <b> 2 of the roller 5 increases, the inner ring 2 becomes too thin due to dimensional constraints, making it difficult to place the roller 5 having a long length. For these reasons, the contact angle ratio is desirably 1: 2 or more and 1: 4 or less.

  The assumed axial load and radial load refer to the axial load and radial load when the average wind power generator is operating most normally in consideration of various conditions such as power generation capacity and installation location. . Therefore, in a double row self-aligning roller bearing used in a wind power generator having different conditions as compared with an average wind power generator, the optimal contact angle ratio may not be 1: 3. However, even in that case, the optimum contact angle ratio falls within the range of 1: 2 to 1: 4.

  Further, by adding a condition that the length L2 of the roller 5 having a long length is 39% or more of the bearing width B, the ratio of the contact angles of the rollers in both rows is made appropriate within the range of the dimensional standard. Double row spherical roller bearings can be obtained. In addition, about the conventional double row self-aligning roller bearing, the ratio of the length L2 of the roller 5 to the bearing width B was investigated. As a result, as shown in FIG. 7, the ratio was found to be 39% or more. The dimensional standard is a standard that defines an inner diameter, an outer diameter, and a bearing width.

  8 and 9 show an example of the spindle support device of the wind power generator. A casing 23a of the nacelle 23 is installed on the support base 21 via a swivel bearing 22 (FIG. 9) so as to be horizontally swivelable. In the casing 23 a of the nacelle 23, a main shaft 26 is rotatably installed via a main shaft support bearing 25 installed in the bearing housing 24, and a blade 27 serving as a swirl wing is formed on a portion protruding from the casing 23 a of the main shaft 26. Is attached. The other end of the main shaft 26 is connected to the speed increaser 28, and the output shaft of the speed increaser 28 is coupled to the rotor shaft of the generator 29. The nacelle 23 is turned at an arbitrary angle by the turning motor 30 via the speed reducer 31. In the illustrated example, two main shaft support bearings 25 are arranged side by side, but may be one.

Another embodiment will be described.
In the following description, the same reference numerals are given to portions corresponding to the matters described in advance in the respective embodiments, and overlapping descriptions are omitted. When only a part of the configuration is described, the other parts of the configuration are the same as those described in advance unless otherwise specified. The same effect is obtained from the same configuration. Not only the combination of the parts specifically described in each embodiment, but also the embodiments can be partially combined as long as the combination does not hinder.

A double-row self-aligning roller bearing according to another embodiment will be described with reference to FIGS.
As shown in FIG. 13, this double row spherical roller bearing 1A includes (1) a cage 10RA with an inclination angle, (2) a crowning 13, (3) a DLC film 14, and (4) a slot 15. I have.

<(1) About a cage with an inclination angle>
One cage 10RA for the right row shown in FIG. 13 is a cage that holds the rollers 5 having a long axial length. The retainer 10RA has an inclination angle β that is inclined inward in the radial direction as the outer diameter surface 12Aa of the column portion 12A moves from the proximal end side toward the distal end side. This inclination angle β is an angle with respect to the bearing center axis O. The inclination angle β of the outer diameter surface 12Aa of the cage 10RA is set to a range (0 <β ≦ α2) that is larger than zero and not more than the maximum diameter angle α2 of the rollers 5 in the right row. The maximum diameter angle α2 is an inclination angle of the position of the maximum diameter D2 _max of the roller 5 in the right row with respect to a plane perpendicular to the bearing center axis O.

  The inner diameter surface of the column portion 12A in the cage 10RA for the right row in this example has an inclined surface portion 12Ab and a flat surface portion 12Ac connected to the inclined surface portion 12Ab. The inclined surface portion 12Ab extends from the base end side of the inner diameter surface of the column portion 12A to the vicinity of the middle in the axial direction of the inner diameter surface, and has an inclination angle γ that inclines radially inward from the base end side toward the vicinity of the middle in the axial direction. . The inclination angle γ is also an angle with respect to the bearing center axis O, and the inclination angle γ is set to be equal to or larger than the inclination angle β (γ ≧ β). In this example, the inclination angle γ is set to be several degrees larger than the inclination angle β. However, it is not limited to this relationship (γ ≧ β). The flat surface portion 12Ac is a flat surface parallel to the bearing center axis O extending in the axial direction from the tip edge of the inclined surface portion 12Ab. In the other cage 10L for the left row, the outer diameter surface and the inner diameter surface of the column portion 12 do not have an inclination angle, in other words, are parallel to the bearing center axis O.

<(2) About Crowning 13>
14 is an enlarged cross-sectional view showing a part (XIV part) of FIG. 13 in an enlarged manner. As shown in FIGS. 13 and 14, the left and right rows of rollers 4 and 5 each have a crowning 13 at the end of the roller rolling surface. The roller rolling surface in this example has a logarithmic crowning shape expressed by a logarithmic curve. However, the crowning 13 is not limited to a logarithmic crowning shape. For example, the roller rolling surface may be a composite R crowning shape. By making the R dimension of the crowning portion smaller than the reference R of the roller rolling surface, the composite R crowning shape that increases the drop amount can be formed.

<(3) DLC film 14>
As shown in FIG. 15, each of the rollers 4 and 5 has a DLC film 14 on the roller rolling surface. The DLC film 14 in this example employs a multilayer structure having high adhesion to the rollers 4 and 5 as the base material. The DLC film 14 has a surface layer 16, an intermediate layer 17, and a stress relaxation layer 18. The surface layer 16 is a film mainly composed of DLC in which only a solid target graphite is used as a carbon supply source and the amount of hydrogen contamination is suppressed. The intermediate layer 16 is a layer mainly composed of at least Cr or W formed between the surface layer 16 and the base material. The stress relaxation layer 18 is formed between the intermediate layer 17 and the surface layer 16.

  The intermediate layer 17 has a structure including a plurality of layers having different compositions, and FIG. 15 illustrates a three-layer structure of 17a to 17c. For example, the layer 17c mainly composed of Cr is formed on the surface of the substrate, the layer 17b mainly composed of W is formed thereon, and the layer 17a mainly composed of W and C is formed thereon. Although the three-layer structure is illustrated in FIG. 15, the intermediate layer 17 may include a number of layers equal to or less than this, if necessary.

  The layer 17a adjacent to the stress relaxation layer 18 can improve the adhesion between the intermediate layer 17 and the stress relaxation layer 18 by mainly including the metal that is the main component of the adjacent layer 17b and carbon. For example, when the layer 17a is mainly composed of W and C, the W content is decreased from the intermediate layer 17b side mainly composed of W toward the stress relaxation layer 18 side mainly composed of C. By increasing the content of (composition gradient), the adhesion can be further improved.

The stress relaxation layer 18 is an inclined layer whose main component is C and whose hardness increases continuously or stepwise from the intermediate layer 17 side to the surface layer 16 side. Specifically, it is a DLC gradient layer obtained by forming a film by using a graphite target in the UBMS method and increasing the bias voltage with respect to the substrate continuously or stepwise. The reason why the hardness increases continuously or stepwise is that the constituent ratio of the graphite structure (SP ² ) and the diamond structure (SP ³ ) in the DLC structure is biased toward the latter as the bias voltage increases.

  The surface layer 16 is a film mainly composed of DLC formed by extension of the stress relaxation layer 18, and in particular, a DLC film with a reduced hydrogen content in the structure. Abrasion resistance is improved by reducing the hydrogen content. In order to form such a DLC film, for example, a method in which hydrogen and a compound containing hydrogen are not mixed into a raw material used for the sputtering process and a sputtering gas by using the UBMS method is used.

The case of using the UBMS method has been exemplified for the method of forming the stress relaxation layer 18 and the surface layer 16, but any other known film forming method may be used as long as the hardness can be changed continuously or stepwise. Can be adopted. The total thickness of the multilayer including the intermediate layer 17, the stress relaxation layer 18, and the surface layer 16 is preferably 0.5 μm to 3.0 μm. If the total film thickness is less than 0.5 μm, the abrasion resistance and mechanical strength are inferior, and if the total film thickness exceeds 3.0 μm, peeling tends to occur.
In this example, the DLC film 14 is provided only on the outer peripheral surfaces of the rollers 4 and 5, but the DLC film 14 may be provided on both end faces of the rollers 4 and 5. In particular, when the DLC film 14 is provided on one end face of each roller 4, 5 guided to the middle collar 8 (FIG. 13), the one end face of each roller 4, 5 becomes difficult to wear, and the rollers 4, 5 Abrasion resistance can be further increased.

<(4) Groove insertion>
As shown in FIG. 16, the inner ring 2 is inserted into the small collar 7 facing the axially outer end surface of the long roller 5 among the small collars 6 and 7 (FIG. 13). A groove 15 is provided. As shown in FIG. 17, an arc-shaped insertion groove 15 is provided at one place in the circumferential direction of the small brim 7 of the inner ring 2. The radius of curvature of the arc 15a of the insertion groove 15 is appropriately set according to the maximum diameter of the roller 5 to be inserted (FIG. 16).
In addition, the same configuration as the above-described embodiment is provided.

<About the effects>
According to the double-row self-aligning roller bearing 1A according to another embodiment, since each of the rollers 4 and 5 has the DLC film 14 on the roller rolling surface, it is possible to improve wear resistance. As a result, the roller rolling surfaces and the raceways 2a, 2b, and 3a of the outer ring 3 are less likely to be worn than those without the DLC film. Further, since the crowning 13 is provided at the end of the roller rolling surface, the edge stress can be relaxed.

  One retainer 10RA that retains the long roller 5 has an inclination angle β in which the outer diameter surface 12Aa of the column portion 12A is inclined radially inward from the proximal end side toward the distal end side. The Pt surface can hold the maximum diameter position of the roller 5. In other words, since one of the cages 10RA has the inclination angle β as described above, the pocket Pt surface of the cage 10RA is maintained near the pitch circle diameter of the rollers 5, and the pocket Pt surface of the cage 10RA during the bearing operation. However, the maximum diameter position of the rollers 5 can be held smoothly. Thereby, the posture stability of the long roller 5 is not impaired, and the long roller 5 can be easily assembled. The inner ring 2 is provided with an insertion groove 15 for inserting the long roller 5 into the bearing in the small brim 7 facing the axially outer end surface of the long roller 5 among the small collars 6, 7. Can be further improved.

In the double row self-aligning roller bearing 1B shown in FIG. 18, the inclination angle β of the outer diameter surface 12Ba of the column portion 12B in one cage 10RB is larger than zero, and the maximum diameter angle α2 of the roller 5 in the right row. The inclination angle γ of the inner diameter surface of the column portion 12B is set to be equal to the inclination angle β of the outer diameter surface. The inclination angle β in this example is set to an angle that is equal to or less than the maximum diameter angle α2 and is substantially close to the maximum diameter angle α2. Further, the inner diameter surface of the column portion 12B is composed only of the inclined surface portion, and the above-described flat surface portion is not provided.
According to the configuration of FIG. 18, since the cage 10RB has the inclination angle β as described above, the pocket Pt surface of the cage 10RB is more reliably maintained in the vicinity of the pitch circle diameter of the roller 5, and is retained during bearing operation. The pocket Pt surface of the container 10RB can hold the maximum diameter position of the roller 5 smoothly and reliably. In addition, the long roller 5 can be easily assembled.

  As mentioned above, although the form for implementing this invention based on the Example was demonstrated, embodiment disclosed here is an illustration and restrictive at no points. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1, 1A, 1B ... Double-row self-aligning roller bearing 2 ... Inner ring 3 ... Outer ring 3a ... Raceway surface 4, 5 ... Roller 6, 7 ... Small collar 8 ... Middle collar 10L, 10R, 10RA, 10RB ... Retainer 11, 11A ... annular portion 12, 12A, 12B ... pillar part 13 ... crowning 14 ... central _D1 max, D2 _{max ...} maximum diameter L1, L2 ... the length of the DLC coating 15 ... grooving 26 ... main shaft A1, A2 ... roller length P ... Point where the lines of action intersect with each other Q ... Center positions S1, S2 of the middle collar in the bearing width direction ... Lines of action θ1, θ2 ... Contact angle

Claims (4)

Between the inner ring and the outer ring, rollers are arranged in two rows in the bearing width direction, the raceway surface of the outer ring is spherical, and the outer surface of the two rows of rollers is a cross section along the raceway surface of the outer ring. A double row spherical roller bearing having a shape,
The two rows of rollers have different lengths, and the contact angle of the long roller is greater than the contact angle of the short roller, and the portion between the two rows of rollers on the outer peripheral surface of the inner ring There is a middle brim, and the center position of the middle brim in the bearing width direction is closer to the longer roller side than the position in the bearing width direction at the point where the action lines forming the contact angles of both rows intersect each other. Double-row self-aligning roller bearing characterized by being displaced.   2. The double row self-aligning roller bearing according to claim 1, wherein the ratio of the contact angle of the short roller and the contact angle of the long roller is in the range of 1: 2 to 1: 4. Spherical roller bearing.   The double row spherical roller bearing according to claim 1 or 2, wherein the double row spherical roller bearing is used for supporting a main shaft of a wind power generator. In the double row spherical roller bearing according to any one of claims 1 to 3,
Each of the rows of rollers is provided with a cage, and each cage has an annular ring portion that guides an axially inner end face of each row of rollers, an axially extending from the annular portion, and a circular shape. A plurality of pillars provided at intervals defined along the circumferential direction, pockets for holding the rollers are provided between the pillars, and one of the cages for holding the long rollers is The outer diameter surface of the column part has an inclination angle inclined inward in the radial direction from the base end side toward the tip end side,
Each of the rollers has a DLC film on the roller rolling surface, and a crowning at an end of the roller rolling surface,
The inner ring is provided between the two rows of rollers on the outer peripheral surface of the inner ring and guides the two rows of rollers, and the end surface on the outer side in the axial direction of each row of rollers provided on both ends of the outer peripheral surface. The inner ring has a double row provided with a slot into which the long roller is inserted into the bearing in a small brim that faces the axially outer end surface of the long roller. Spherical roller bearing.

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