JP2005249072A - Self-aligning type bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a self-aligning type double-row bearing, stably used as a free side bearing of a rotating shaft for a long time. <P>SOLUTION: A lubricating hole 9 allowing grease in the interior of the bearing to leaking out with the rotation of an inner ring 4 and an annular lubricating groove 10 connected to the outlet of the lubricating hole 9 are provided in the central part in the axial direction of the outer ring 2, and an inlet part 9a of the lubricating hole 9 is formed tapered so that as it approaches the inside diameter surface of an outer ring 2, it becomes wider, whereby the grease is made to more easily flow from the interior of the bearing toward a clearance gap between the outside diameter surface of the outer ring 2 and the inner surface of the housing A to keep the slidability in a space up to the housing A favorable over a long period of time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a double row self-aligning bearing that supports the free side of a rotating shaft.

  Self-aligning bearings are widely used to support rotating shafts of general industrial machines because they can absorb inclinations due to shaft mounting errors and deflections and have a large load capacity. However, since the bearing clearance in the axial direction is extremely small due to the structure, especially when the rotating shaft is a long shaft, the axial expansion and contraction due to temperature changes of the rotating shaft cannot be sufficiently absorbed in the bearing, and the thrust force is received. There are easy difficulties.

  For this reason, when using a self-aligning bearing as the free-side bearing of the rotating shaft, generally, the bearing slides with the housing incorporating the bearing by applying a lubricant to the outer surface of the bearing outer ring. To absorb the expansion and contraction of the rotating shaft.

  However, with this method, the lubricant applied to the bearing gradually disperses around the outer surface of the outer ring with the passage of time from the start of use of the bearing, and the slidability between the bearing and the housing decreases. Resulting in. For this reason, the bearing is subject to excessive thrust force due to a squeezing or tensioning with the housing, and the performance is likely to be reduced due to the temperature rise, resulting in a short life.

  On the other hand, when the self-aligning bearing is a double row type, a lubrication hole through which the lubricant such as grease inside the bearing leaks with the rotation of the inner ring at the center in the axial direction of the outer ring, and the outlet of this lubrication hole It has also been conventionally considered to provide a continuous lubricating groove to the outer ring outer diameter surface by providing a continuous annular lubricating groove.

However, in the shape of the lubrication hole 53 and the lubrication groove 54 of the outer ring 52 of the conventional self-aligning bearing (spherical roller bearing) 51 shown in FIG. It was difficult to flow into the gap between the surface and the inner surface of the housing A, and sufficient slidability was not obtained.
“Sealed spherical roller bearings WA type”, NTN Corporation, catalog, CAT.No. 3702-II / J, 2000

  An object of the present invention is to provide a double-row type self-aligning bearing that can be stably used for a long time as a free-side bearing of a rotating shaft.

  In order to solve the above-described problems, the present invention provides a lubrication hole through which the lubricant inside the bearing leaks as the inner ring rotates, and an annular lubrication groove that continues to the outlet of the lubrication hole. In the double-row type self-aligning bearing provided with the above, the shape of the lubricating hole or groove is improved so that the lubricant can easily flow from the inside of the bearing toward the gap between the outer ring outer diameter surface and the housing inner surface. It is. As a result, a sufficient amount of lubricant can be continuously supplied between the bearing and the housing to maintain good slidability over a long period of time, so that the bearing always slides smoothly even when the rotating shaft expands and contracts. It will be able to absorb the expansion and contraction of the rotating shaft with certainty.

  The shape of the specific lubrication hole that facilitates the inflow of the lubricant into the gap between the outer ring and the housing includes a tapered shape whose inlet portion becomes wider as it approaches the inner diameter surface of the outer ring, and a cross-sectional shape of the outer ring. An elliptical shape that is long in the axial direction can be adopted.

  On the other hand, as the specific shape of the lubricating groove, it is possible to adopt a chamfered boundary portion between the groove side surface and the outer ring outer diameter surface or a groove depth of 1 to 3% of the groove width dimension. it can. The groove depth is made shallower than the conventional one (3-5% of the groove width dimension) in a range where no clogging of the lubricant occurs, so that the retention of the lubricant in the groove is reduced. The lubricant can easily flow into the gap.

  Further, even if a groove extending in the axial direction of the outer ring is provided from the lubricating groove and the lubricant flows into the gap between the outer ring and the housing also from the axial groove, the slidability can be kept good.

  As the type of the self-aligning bearing, any of a self-aligning roller bearing and a self-aligning ball bearing can be adopted.

  As described above, the double-row self-aligning bearing of the present invention is sufficiently supplied with lubricant from the inside of the bearing to the gap between the outer ring and the housing as the inner ring rotates, and is slidable between the housing and the housing. Therefore, even when the free side of the rotating shaft is supported, it can be used stably over a long period of time without causing twisting or stretching.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. As shown in FIG. 1, the self-aligning bearing 1 is a double row self-aligning roller bearing that is slidably fitted into the inner surface of the housing A and supports the free side of the rotating shaft B. Two rows of spherical rollers 7 held by a cage 6 are incorporated between the spherical track 3 on the side and the two spherical tracks 5 on the outer diameter side of the inner ring 4. In addition, the bearing internal space surrounded by the two race rings 2 and 4 and the seal member 8 that closes both side ends of the gap is filled with grease as a lubricant.

  In the central portion of the outer ring 2 in the axial direction, circular lubrication holes 9 are provided at four locations in the circumferential direction to allow grease inside the bearing to leak as the inner ring 4 rotates, and continuous to the outlets of these lubrication holes 9. Thus, an annular lubricating groove 10 is provided. The inlet 9a of the lubrication hole 9 is formed in a tapered shape that becomes wider as it approaches the inner surface of the outer ring 2. Further, the width of the lubricating groove 10 also becomes wider as it approaches the outer diameter surface of the outer ring 2 from the groove bottom side.

  This bearing 1 has the above-described configuration, and since the lubricating hole inlet 9a is tapered and the resistance to the flow of grease is small, the grease is directed from the inside of the bearing to the gap between the outer diameter surface of the outer ring 2 and the inner surface of the housing A as compared with the prior art. The slidability with the housing A is kept good for a long period of time. Therefore, even if the rotating shaft B expands and contracts due to a temperature change, the rotating shaft B always slides smoothly with respect to the housing A, and the expansion and contraction of the rotating shaft B can be reliably absorbed.

  2 to 5 show examples of the outer ring 2 in which the shape of the lubrication hole 9 or the lubrication groove 10 is different from the example of FIG. In the outer ring 2 shown in FIG. 2, the cross-sectional shape of the lubrication hole 9 is an ellipse that is long in the direction of the outer ring 2 axis. In the outer ring 2 of FIG. 3, the boundary 11 between the side surface of the lubrication groove 10 and the outer diameter surface of the outer ring 2 is chamfered. Thus, the resistance to the flow of grease is reduced.

  Further, in the outer ring 2 shown in FIG. 4, the depth of the lubricating groove 10 is made shallower than the conventional one to 1 to 3% of the groove width dimension, so that the grease in the groove 10 is within a range where no grease clogging occurs. , So that the grease can easily flow into the gap between the outer ring 2 and the housing A.

  On the other hand, the outer ring 2 shown in FIG. 5 is provided with a groove 10a extending in the axial direction of the outer ring 2 from the lubricating groove 10, and grease also flows into the gap between the outer ring 2 and the housing A from this axial groove 10a. The slidability between them is kept good.

  In order to confirm the sliding performance of the bearing of the above-described embodiment, an experiment using the testing machine shown in FIG. 6 was performed. In this testing machine, a rotating shaft B is supported by a self-aligning roller bearing 1 and a cylindrical roller bearing 13 incorporated on both left and right sides of a testing machine main body 12 via a housing A, and a radial load (see FIG. The rotating shaft B is rotated while applying a white arrow), and the self-aligning roller bearing 1 is pushed and slid with the housing A by turning the handle 14 attached to one end of the testing machine body 12. It is like that. The axial displacement of the rotary shaft B that moves integrally with the bearing 1 is absorbed by the gap of the coupling 15 provided on the other end side of the tester main body 12.

  In the experiment, as a test bearing of the self-aligning roller bearing 1 incorporated in the testing machine of FIG. 6, those corresponding to the examples of FIGS. The outer ring outer diameter surface with grease applied (Comparative Example 1) and the outer ring and the housing without lubrication (Comparative Example 2) were prepared. Then, in the test machine, the test bearing incorporated was slid in a state where the rotating shaft B was rotated under the conditions of radial load: 9.8 kN and rotational speed: 2000 rpm, and the load cell 16 applied the force required at this time. The friction force between the test bearing and the housing A was measured. The measurement of the frictional force was performed immediately after the rotation of the rotating shaft B was started and after 20 hours had elapsed. The result of comparing the frictional force of each test bearing is shown in FIG.

  7 (a) and 7 (b), the bearing of each example has a frictional force of about 40 to 60% of that of Comparative Example 2 without lubrication regardless of the measurement timing, and slidability with the housing A. As can be seen from the above, the free side bearing can be used stably for a long period of time. On the other hand, in Comparative Example 1, after 20 hours from the start of rotation, the frictional force increases to about 70% of Comparative Example 2, and the effect of applying grease to the outer ring outer diameter surface may decrease with time. confirmed.

  The present invention can be applied to a self-aligning ball bearing of a double row type in addition to the self-aligning roller bearing as in the embodiment described above. FIG. 8 shows an embodiment in which the present invention is applied to a self-aligning ball bearing. This bearing 17 has the same configuration as the bearing 1 shown in FIG. 1 except that the rolling elements incorporated between the outer ring 2 and the inner ring 4 are balls 18. Accordingly, like the bearing 1 of FIG. 1, the inlet 9a of the lubrication hole 9 of the outer ring 2 is tapered, so that the lubricant is sufficiently supplied from the inside of the bearing 17 to the gap between the outer ring 2 and the housing A. Can be used stably for a long time as a free side bearing.

  The shape of the lubrication hole 9 or the lubrication groove 10 of the outer ring 2 of the self-aligning ball bearing 17 can be changed as in the examples shown in FIGS.

Front sectional view of self-aligning type bearing (self-aligning roller bearing) of the embodiment Front sectional view of outer ring showing examples of different lubricating hole shapes Front sectional view of outer ring showing examples of different lubricating groove shapes Front sectional view of the outer ring showing another example with different lubricating groove shape Front sectional view of the outer ring showing an example in which an axial groove is provided from the lubricating groove Front sectional view of the testing machine used in the experiment to confirm the sliding performance a and b are graphs showing the results of confirmation experiments of sliding performance, respectively. Front sectional view of a self-aligning bearing (self-aligning ball bearing) of another embodiment Front sectional view showing an example of a conventional self-aligning bearing (self-aligning roller bearing)

Explanation of symbols

1 Self-aligning bearings (Spherical roller bearings)
2 Outer ring 4 Inner ring 7 Spherical roller 8 Seal member 9 Lubrication hole 9a Inlet part 10 Lubrication groove 10a Axial groove 11 Boundary part 17 Self-aligning bearing (self-aligning ball bearing)
18 Ball A Housing B Rotating shaft

Claims (7)

  A double-row self-aligning type that has a lubrication hole through which the lubricant inside the bearing leaks as the inner ring rotates, and an annular lubrication groove that continues to the outlet of the lubrication hole at the axial center of the outer ring 2. A self-aligning bearing according to claim 1, wherein an inlet portion of the lubricating hole is formed in a tapered shape that becomes wider as it approaches the inner surface of the outer ring.   A double-row self-aligning type that has a lubrication hole through which the lubricant inside the bearing leaks as the inner ring rotates, and an annular lubrication groove that continues to the outlet of the lubrication hole at the axial center of the outer ring 2. A self-aligning bearing according to claim 1, wherein a cross-sectional shape of the lubricating hole is an ellipse that is long in the axial direction of the outer ring.   A double-row self-aligning type that has a lubrication hole through which the lubricant inside the bearing leaks as the inner ring rotates, and an annular lubrication groove that continues to the outlet of the lubrication hole at the axial center of the outer ring 2. A self-aligning bearing according to claim 1, wherein a boundary portion between the side surface of the lubricating groove and the outer ring outer diameter surface is chamfered.   A double-row self-aligning type that has a lubrication hole through which the lubricant inside the bearing leaks as the inner ring rotates, and an annular lubrication groove that continues to the outlet of the lubrication hole at the axial center of the outer ring The self-aligning bearing according to claim 1, wherein a depth of the lubricating groove is 1 to 3% of a groove width dimension.   A double-row self-aligning type that has a lubrication hole through which the lubricant inside the bearing leaks as the inner ring rotates, and an annular lubrication groove that continues to the outlet of the lubrication hole at the axial center of the outer ring A self-aligning bearing characterized in that a groove extending in the axial direction of the outer ring from the lubricating groove is provided in the bearing.   The self-aligning bearing according to any one of claims 1 to 5, wherein the type of the self-aligning bearing is a self-aligning roller bearing.   6. The self-aligning bearing according to claim 1, wherein the self-aligning bearing is a self-aligning ball bearing.

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