JP2022163432A - rolling bearing - Google Patents

Abstract

To provide a rolling bearing which can inhibit a shortage in the amount of oil on a rolling surface to inhibit occurrence of seizure and wear even when rotating at high speed.SOLUTION: A rolling bearing includes: an outer ring 21 in which an outside raceway 21b is formed on an inner peripheral surface 21a; an inner ring 22 in which an inside raceway 22b is formed on an outer peripheral surface 22a; and a plurality of rolling elements 23 disposed between the outside raceway 21b and the inside raceway 22b. In the rolling bearing, the outer ring 21 and the inner ring 22 may rotate around a rotation axis relative to each other. An end as seen in the rotation axis direction of one of the outer ring 21 and the inner ring 22 includes a fixed plate 26 which prevents flow of oil flowing from a space between the outer ring 21 and the inner ring 22 to the outside. The fixed plate 26 is formed with an oil suction port 26a penetrating therethrough in the rotation axis direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to rolling bearings.

Patent Literature 1 discloses a method in which a nozzle for injecting air oil is installed in a rolling bearing to supply oil to the rolling elements in the bearing, thereby supplying lubricating oil to the inside of the bearing during high-speed rotation with a small amount of lubricating oil. disclosed.

JP-A-2002-54643

In the lubricating oil supply method disclosed in Patent Document 1, the rolling bearing used is a dedicated product having slopes on the inner and outer cotton for air oil lubrication, and the slopes for injecting air oil are provided on the slopes to rotate with the injection nozzle parts. There is a gap to avoid contact with the inner ring. As a result, the supplied air-oil does not enter the rotating body and leaks out through the gap, possibly causing lubrication failure. Furthermore, by rotating the rolling bearing at a high speed, if the amount of oil flowing into the rolling surfaces, which are in contact with the raceway surfaces of the outer and inner rings while the rolling elements are rolling, becomes extremely small, the lack of oil on the rolling surfaces can be prevented. It may become uncontrollable.

Therefore, we created a tester that can visualize the state of lubrication inside a ball bearing that rotates at high speed, and observed the state of lubrication inside the ball bearing when rotating a conventional ball bearing at high speed. The ball bearing 1 used in the evaluation test has a shape corresponding to type 6808, and is a visualization bearing in which only the outer ring 2 is made of quartz. The overall structure of the ball bearing 1 is shown in FIGS. 3 and 4. FIG. As shown in FIGS. 3 and 4, the ball bearing 1 includes an outer ring 2 made of transparent quartz, an inner ring 3 made of steel, steel balls 4 as rolling elements, and the steel balls 4 spaced apart in the circumferential direction. and a retainer 5 that holds it so that it can roll.

The shape of the retainer 5 is shown in FIGS. 5, 6 and 7. FIG. In order to clarify the shape of the retainer 5, only the cross section of the retainer 5 and the steel balls 4 are shown in FIG. The retainer 5 has a pocket 6 formed on one side in the axial direction for holding the steel ball 4 in a rollable manner, and the pocket 6 is open on one side. A side surface 7 on the other side in the axial direction of the retainer 5 is flat. In addition, an oil passage hole penetrating in the axial direction is not formed in the side surface 7 of the retainer.

FIG. 8 shows an outline of the testing machine used for the evaluation test. A horizontally extending rotary shaft 8 is rotatably supported by two shaft support bearings 9 and rotated by a motor 10 . The rotating shaft 8 is inserted and fixed inside the inner ring 3 of the ball bearing 1 , and the inner ring 3 rotates together with the rotating shaft 8 . The outer ring 2 of the ball bearing 1 is fixed inside the housing 11 . A camera 12 is arranged above the ball bearing 1, and an observation hole 13 is formed in the housing 11 above the ball bearing 1, so that the camera 12 can photograph the top of the outer ring 2 from above. .

An oil supply nozzle 14 supplies oil between the top portion of the outer ring 2 and the inner ring 3, and the oil accumulated in the housing 11 below the ball bearing 1 is recovered by an oil pump 15 and circulated. Toyota Auto Fluid WS, which is commercially available ATF (Automatic Transmission Fluid), mixed with coumarin-6, which is a fluorescent agent, was used as the oil, and the oil amount distribution was observed by a fluorescence method. An LED flash illumination with a wavelength of 405 nm was used as excitation light.

FIG. 9 is a top view of the ball bearing 1. FIG. Since the outer ring 2 is made of transparent quartz, when the ball bearing 1 is viewed from above, the raceway surface 3a of the inner ring 3 and the positions of the steel balls 4 can also be confirmed. The area surrounded by broken lines in FIG. 9 is the observation area of the camera 12 . The observation area has a field of view of 23.6 mm×17.7 mm. The oil distribution inside the rotating ball bearing 1 was observed by setting the time per light emission of the LED flash illumination to 3 μsec and irradiating the light emission in accordance with the frame note of 40 fps of the camera 12 . The amount of oil supplied to the ball bearing 1 was constant at 100 ml/min, the radial load applied to the ball bearing 1 from above was also constant at 300 N, and the shaft rotation speed was changed between about 2000 rpm and about 20000 rpm for observation.

10 and 11 schematically show the observation results of the oil amount distribution around the rolling surface. FIG. 10 shows the observation results when the shaft rotation speed is about 2000 rpm (strictly 1910 rpm), and FIG. 11 shows the observation results when the shaft rotation speed is about 20000 rpm (strictly 20200 rpm). 10 and 11, the positions of the steel balls 4 are indicated by solid lines, the center lines of the steel balls 4 by one-dot chain lines, and the positions of the retainer 5 by two-dot chain lines. The steel ball 4 revolves toward the right side in FIGS. 10 and 11 . The refueling nozzle 14 is also depicted in FIGS. 10 and 11 . In FIG. 10 and FIG. 11 , areas where more oil is present are shown in darker gray, and white areas indicate that almost no oil was present.

As shown in FIG. 10, under the low rotation condition of about 2000 rpm shaft rotation speed, oil was generally filled except for the vicinity of the exit side of the steel ball 4 (the left side of the steel ball 4 in FIG. 10). On the exit side of the steel ball 4, there is a region where the oil is scarce.

As shown in FIG. 11, under high rotation conditions of about 20,000 rpm, the revolution raceway of the steel balls 4 and the cage 5 is not filled with oil, and the oil is distributed axially outside the revolution raceway. distributed near the boundary. This is because, at high speeds, the speed at which the oil is removed due to the revolution of the steel balls 4 and the rotation of the cage 5 is excessively increased relative to the inflow speed of the oil, and the increase in the revolution speed of the steel balls 4 , and the expansion of the cavitation region on the exit side of the steel ball 4 (left side of the steel ball 4 in FIG. 11). On the inlet side of the steel ball 4 (on the right side of the steel ball 4 in FIG. 11), there was a triangular portion with a large amount of oil. It is considered that this is because the oil is supplied from the inner ring 3 side to the opening of the U-shaped pocket 6 of the retainer 5 . However, in any case, compared to the low speed condition, the oil at the inlet side of the steel ball 4 and the top portion of the steel ball 4, which is the rolling surface with the outer ring 2, is less under the high speed condition. It is determined that there is an oil shortage. From the viewpoint of friction torque reduction, the smaller the amount of oil on the rolling surface, the better the tendency. However, from the viewpoint of preventing wear and seizure, it is necessary to suppress an excessive shortage of oil.

Thus, as a result of observing the oil amount distribution inside the ball bearing 1, during high-speed rotation, the oil is pushed aside by the steel balls 4 and the cage 5 rotating at high speed, and the amount of oil flowing into the orbital portion thereof is small. It turned out to be very few. In this case, even if seizure and wear can be suppressed by improving the oil retention property according to the measures disclosed in Patent Document 1 in short-time use, seizure and wear will occur in long-term use conditions because the oil will eventually be depleted. is considered to be uncontrollable. Therefore, in order to suppress seizure and wear over a long period of time in a ball bearing that rotates at high speed, it is necessary to promote the inflow of oil into the raceways of the outer ring 2 and the inner ring 3. is difficult to deal with only by giving

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a rolling bearing capable of suppressing insufficient amount of oil on the rolling surface and suppressing the occurrence of seizure and wear even when rotating at high speed.

A rolling bearing according to the present invention comprises an outer ring having an outer raceway formed on its inner peripheral surface, an inner ring having an inner raceway formed on its outer peripheral surface, and rolling elements arranged between the outer raceway and the inner raceway. , wherein the outer ring and the inner ring are relatively rotatable about a rotation axis, wherein the outer ring and the A fixed plate is provided to prevent the flow of oil flowing out from between the inner ring and the fixed plate, and the fixed plate is formed with an oil suction port penetrating in the direction of the rotation axis.

According to the present invention, the oil supplied between the outer ring and the inner ring is sucked from the oil suction port and flowed toward the oil suction port, thereby promoting the inflow of the oil to the rolling surface. Even so, it is possible to provide a ball bearing that can suppress the shortage of the amount of oil on the rolling surface and suppress the occurrence of seizure and wear.

In one aspect of the rolling bearing according to the present invention, the oil is supplied between the outer ring and the inner ring from the opposite side of the fixed plate in the direction of the rotating shaft, and the oil suction port is provided with respect to the outer ring. Assuming that the direction in which the inner ring rotates and advances is the front side in the circumferential direction, the oil supply position may be arranged within a range of 45 degrees to the front side in the circumferential direction.

According to this aspect, the oil can flow efficiently so as not to hinder the oil flow during high-speed rotation.

In one aspect of the rolling bearing according to the present invention, the fixed plate may be provided so as to be substantially perpendicular to the rotating shaft.

INDUSTRIAL APPLICABILITY The present invention can provide a rolling bearing capable of suppressing insufficient amount of oil on the rolling surface and suppressing the occurrence of seizure and wear even when rotating at high speed.

1 is a side view of a rolling bearing of an embodiment of the present disclosure; FIG. FIG. 2 is a cross-sectional view taken along line DD in FIG. 1; FIG. 3 is a side view of a ball bearing used in an evaluation test for observing the lubrication state between the raceway surface of an outer ring and the rolling surface of a rolling element; FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3; It is the figure which expanded and showed a part of side view of the ball bearing used for the evaluation test. FIG. 6 is a cross-sectional view taken along the line BB in FIG. 5; FIG. 6 is a sectional view taken along line CC in FIG. 5; It is a figure which shows the outline of the tester used for the evaluation test which observes the lubricating state between the raceway surface of an outer ring, and the rolling surface of a rolling element. FIG. 4 is a diagram showing an observation area in an evaluation test for observing the lubrication state between the raceway surface of the outer ring and the rolling surface of the rolling element; FIG. 5 is a diagram schematically showing observation results of the oil amount distribution around the rolling surface when the shaft rotation speed is about 2000 rpm. FIG. 4 is a diagram schematically showing observation results of the oil amount distribution around the rolling surface when the shaft rotation speed is about 20000 rpm.

Hereinafter, a rolling bearing 20 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 and 2. FIG. FIG. 2 is a cross-sectional view taken along line DD in FIG. As shown in FIGS. 1 and 2, the rolling bearing 20 is a ball bearing including an outer ring 21, an inner ring 22, rolling elements 23 and a cage 25. As shown in FIG. An outer raceway 21b is formed on the inner peripheral surface 21a of the outer ring 21 so as to follow the surface of the spherical rolling element 23 . An inner raceway 22b is formed on the outer peripheral surface 22a of the inner ring 22 so as to follow the surfaces of the rolling elements 23 . The outer raceway 21b of the outer ring 21 and the inner raceway 22b of the inner ring 22 are provided at predetermined intervals along the circumferential direction of the annular rolling bearing 20 . The rolling elements 23 are held in a space formed by the outer raceway 21b of the outer ring 21 and the inner raceway 22b of the inner ring 22 in a rollable state. Moreover, the retainer 25 is arranged between the outer ring 21 and the inner ring 22, and retains the plurality of rolling elements 23 so that they can roll at predetermined intervals in the circumferential direction. The rolling bearing 20 has a configuration in which the outer ring 21 and the inner ring 22 can rotate relative to each other about the central axis of the outer ring 21 and the inner ring 22 as the rolling element 23 rolls between the outer ring 21 and the inner ring 22. It is said that

The rolling bearing 20 is used, for example, in applications where the direction of rotation is mainly determined in one direction, such as drive system units for automobiles and machine tools. When the inner ring 22 is rotated in the direction of rotation mainly used in the rolling bearing 20, the inner ring 22 rotates counterclockwise as indicated by the arrow in FIG. The rolling elements 23 also revolve in the same rotational direction as the inner ring 22 , and the retainer 25 also rotates in the same rotational direction as the inner ring 22 . Hereinafter, the direction in which the inner ring 22 rotates with respect to the outer ring 21 due to this rotation is defined as the front side in the circumferential direction.

The rolling bearing 20 comprises a fixed plate 26 for blocking oil flow. The fixed plate 26 is a plate-like member arranged between the inner peripheral surface 21 a of the outer ring 21 and the outer peripheral surface 22 a of the inner ring 22 from the end of the rolling bearing 20 in the rotation axis direction. The fixed plate 26 is arranged at a position that blocks the flow of oil flowing out from between the outer ring 21 and the inner ring 22 . It is preferable that the fixed plate 26 be an annular member and arranged so as to be substantially perpendicular to the rotation axis of the rolling bearing 20 . When the outer ring 21 is fixed and the inner ring 22 is rotated with respect to the outer ring 21, the fixing plate 26 is preferably fixed to the end portion of the outer ring 21 in the rotation axis direction. In this case, it is preferable that the fixed plate 26 does not come into contact with the inner ring 22 and a gap is provided between the fixed plate 26 and the outer peripheral surface 22a of the inner ring 22 . When the inner ring 22 is fixed and the outer ring 21 is rotated with respect to the inner ring 22 , the fixing plate 26 is preferably fixed to the end portion of the inner ring 22 in the rotation axis direction. In this case, it is preferable that the fixed plate 26 does not come into contact with the outer ring 21 and that a gap is provided between the fixed plate 26 and the inner peripheral surface 21 a of the outer ring 21 . An oil suction port 26a is formed through the fixed plate 26 in the direction of the rotation axis.

An oil supply nozzle 27 is arranged on the opposite side of the fixed plate 26 of the rolling bearing 20 in the rotation axis direction. Oil supply nozzle 27 is used to supply oil between inner peripheral surface 21 a of outer ring 21 and inner peripheral surface 21 a of inner ring 22 .

A suction pipe 28 is inserted into the oil suction port 26 a of the fixed plate 26 . The suction pipe 28 is connected to an oil pump (not shown). The oil supplied from the oil supply nozzle 27 is sucked by the oil pump from the oil suction port 26a. Therefore, the oil supplied from the oil nozzle 27 flows between the inner peripheral surface 21a of the outer ring 21 and the outer peripheral surface 22a of the inner ring 22 from the oil nozzle 27 toward the suction pipe 28 (left side in FIG. 2). At this time, since the fixing plate 26 is provided, the oil can be effectively sucked when the oil is sucked from the oil suction port 26a by the oil pump. Therefore, the flow rate of oil between the inner peripheral surface 21a of the outer ring 21 and the outer peripheral surface 22a of the inner ring 22 can be increased.

The oil supplied between the outer raceway 21b and the inner raceway 22b passes between the outer raceway 21b and the rolling elements 23, between the inner raceway 22b and the rolling elements 23, and between the rolling elements 23 adjacent in the circumferential direction. Therefore, by increasing the flow rate of oil between the inner peripheral surface 21a of the outer ring 21 and the outer peripheral surface 22a of the inner ring 22, the oil between the outer raceway 21b and the rolling elements 23 and between the inner raceway 22b and the rolling elements 23 is increased. The flow rate of the oil is also increased, and the oil can be effectively supplied between the outer raceway 21b and the rolling elements 23 and between the inner raceway 22b and the rolling elements 23. In this manner, the rolling bearing 20 can effectively supply oil to the rolling surface, so that it is possible to suppress the shortage of oil on the rolling surface during high-speed rotation, thereby suppressing the occurrence of seizure and wear. can.

As shown in FIG. 1, the oil suction port 26a is preferably provided at an angle .theta. The angle θ is preferably within 45 degrees. By providing the oil suction port 26a on the front side in the circumferential direction relative to the oil supply nozzle 27 in this manner, the oil can flow efficiently without hindering the flow of the oil when the rolling bearing 20 rotates at high speed.

The present invention is not limited to the forms described above, and can be implemented in various forms within the scope of the gist of the present invention. For example, the configuration of the present invention can be applied to roller bearings instead of ball bearings.

REFERENCE SIGNS LIST 1 ball bearing 2 outer ring 3 inner ring 3a raceway surface 4 steel ball 5 retainer 6 pocket 7 side surface 8 rotating shaft 9 shaft support bearing 10 motor 11 housing 12 camera 13 observation hole , 14 oil supply nozzle, 15 oil pump, 20 rolling bearing, 21 outer ring, 21a inner peripheral surface, 21b outer raceway, 22 inner ring, 22a outer peripheral surface, 22b inner raceway, 23 rolling element, 25 retainer, 26 fixed plate, 26a oil Suction port, 27 lubricating nozzle, 28 suction pipe.

Claims (3)

An outer ring having an outer raceway formed on its inner peripheral surface, an inner ring having an inner raceway formed on its outer peripheral surface, and rolling elements disposed between the outer raceway and the inner raceway; A rolling bearing in which the outer ring and the inner ring are relatively rotatable,
A fixing plate is provided at the rotational axis direction end of either the outer ring or the inner ring to prevent the flow of oil flowing out from between the outer ring and the inner ring,
A rolling bearing, wherein the fixed plate is formed with an oil suction port penetrating in the direction of the rotation axis. A rolling bearing according to claim 1,
the oil is supplied between the outer ring and the inner ring from the opposite side of the fixed plate in the direction of the rotation axis;
The oil suction port is arranged within a range of 45 degrees or less to the front side in the circumferential direction from the oil supply position, with the direction in which the inner ring rotates relative to the outer ring as the front side in the circumferential direction. rolling bearing. A rolling bearing according to claim 1 or 2,
A rolling bearing, wherein the fixed plate is provided so as to be substantially perpendicular to the rotating shaft.

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