JP2022191885A - ball bearing - Google Patents

Abstract

To provide a rolling bearing which can suppress shortage of oil on a rolling surface and can suppress seizure or abrasion even at high-speed rotation.SOLUTION: A ball bearing 20 includes an outer ring 21 having an outside raceway 21a formed on a radial inside surface, an inner ring 22 having an inside raceway 22a formed on a radial outside surface, a plurality of balls 23 disposed between the outside raceway 21a and the inside raceway 22a, and an annular retainer 25 having a plurality of pockets 24 for retaining the balls 23 so as to be rolled at intervals in a circumferential direction. The outer ring 21 and the inner ring 22 are relatively rotatable around a central axis. A protrusion 26 protruding in a radial direction is formed on at least one of an outer peripheral surface and an inner peripheral surface of the retainer 25, and the protrusion 26 guides oil to a rolling surface of the ball 23 by rotation of the retainer 25.SELECTED DRAWING: Figure 1

Description

The present invention relates to ball bearings.

In Patent Document 1, a retainer that retains the rolling elements of a rolling bearing so as to be able to roll is formed of a resin composition, and dimples are formed scatteredly on the sliding contact surface of the retainer with which the rolling elements are in sliding contact. An oily ball bearing is disclosed.

JP 2008-144777 A

Japanese Patent Laid-Open No. 2004-100000 proposes a measure for improving oil retention by providing an oil reservoir with dimples on the sliding contact surface of a retainer on which the rolling elements are in sliding contact, thereby suppressing oil film depletion during high-speed rotation. However, by rotating the bearing at high speed in the first place, if the amount of oil flowing into the rolling contact surface where the rolling elements roll and contact the raceway surfaces of the outer ring and the inner ring becomes extremely small, the measures proposed in Patent Document 1 can be used to retain the oil. Even if the oil retaining property of the sliding contact surface of the container is improved, it may not be possible to suppress the shortage of oil on the rolling surface.

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. 11 and 12. FIG. 12 is a cross-sectional view taken along the line AA in FIG. 11. FIG. As shown in FIGS. 11 and 12, 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. 13, 14 and 15. FIG. 14 is a sectional view taken along line BB in FIG. 13, and FIG. 15 is a sectional view taken along line CC in FIG. In order to clearly show the shape of the cage 5, only the cross section of the cage 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. 16 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.

17 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. An area surrounded by a dashed line in FIG. 13 is an observation area of the camera 12. In FIG. 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.

18 and 19 schematically show the observation results of the oil amount distribution around the rolling surface. FIG. 18 shows the observation results when the shaft rotation speed is about 2000 rpm (strictly 1910 rpm), and FIG. 19 shows the observation results when the shaft rotation speed is about 20000 rpm (strictly 20200 rpm). 18 and 19, 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. 18 and 19. FIG. The refueling nozzle 14 is also depicted in FIGS. 18 and 19 . In FIGS. 18 and 19, areas where a large amount of oil is present are shown in darker gray, and white areas indicate that almost no oil was present.

As shown in FIG. 18, under low rotation conditions where the shaft rotation speed is about 2000 rpm, oil was generally filled except for the vicinity of the outlet side of the steel balls 4 (the left side of the steel balls 4 in FIG. 18). On the exit side of the steel ball 4, there is a region where the oil is scarce.

As shown in FIG. 19, under high rotation conditions of about 20000 rpm, the revolution raceway of the steel balls 4 and the cage 5 is not filled with oil, and the oil is not filled with oil on the outside of the revolution raceway in the axial direction. 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. 19). On the inlet side of the steel ball 4 (on the right side of the steel ball 4 in FIG. 19), 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 of a ball bearing rotating at high speed over a long period of time, it is necessary to promote the inflow of oil to the inlet side of the steel balls 4 .

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a ball 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 ball bearing according to the present invention is arranged between an outer ring having an outer raceway formed on a radially inner surface, an inner ring having an inner raceway formed on a radially outer surface, and the outer raceway and the inner raceway. and an annular retainer formed with a plurality of pockets for rotatably retaining the balls at intervals in the circumferential direction, the outer ring and the inner ring centering on a central axis. is relatively rotatable, wherein at least one of the outer peripheral surface and the inner peripheral surface of the retainer is provided with radially protruding protrusions or radially recessed grooves, and the holding It is characterized in that the protrusion or the groove guides the oil to the rolling surface of the ball as the device rotates.

According to the present invention, since the protrusions or grooves guide the oil to the rolling surfaces of the balls as the cage rotates, the lack of oil on the rolling surfaces is suppressed even when the cage rotates at high speeds, preventing seizure and wear. can be suppressed.

In one aspect of the ball bearing according to the present invention, the retainer has a side surface perpendicular to the central axis at one end in the direction of the central axis, and the side surface is opposite to the side surface in the direction of the central axis. The pocket is formed in the outer peripheral surface and the inner peripheral surface of the retainer, and the protrusion extending from the one end in a direction obliquely crossing the direction of the central axis at a predetermined angle with respect to the direction of the central axis may be provided.

According to this aspect, due to the rotation of the cage, the projections extending in the direction obliquely crossing the direction of the central axis are formed near the side surfaces of the cage as shown in FIG. Therefore, since the oil is guided to the rolling surface of the ball, even if the ball rotates at high speed, the shortage of oil on the rolling surface can be suppressed, and seizure and wear can be suppressed.

In one aspect of the ball bearing according to the present invention, a plurality of the protrusions extending in parallel are provided between the pockets adjacent in the circumferential direction, and the predetermined angle is 10 degrees or more and 70 degrees or less. The height at which the protrusions protrude in the radial direction is 0.5 mm or more and 5 mm or less, the thickness of the protrusions in the circumferential direction is 1 mm or more and 5 mm or less, and the pockets are adjacent to each other between the pockets. A circumferential interval between the protrusions may be 1 mm or more and 20 mm or less.

According to this aspect, it is possible to suppress the shortage of the amount of oil on the rolling surface even when rotating at a high speed while suppressing the agitation resistance of the oil, thereby suppressing the occurrence of seizure and wear.

In one aspect of the ball bearing according to the present invention, the retainer has a side surface perpendicular to the central axis at one end in the direction of the central axis, and the side surface is opposite to the side surface in the direction of the central axis. The grooves extending from the one end in a direction obliquely intersecting the direction of the central axis at a predetermined angle are formed in the outer peripheral surface and the inner peripheral surface of the retainer. may be provided.

According to this aspect, due to the rotation of the cage, the grooves extending in the direction obliquely crossing the direction of the central axis are formed from the regions of high oil concentration formed near the side surfaces of the cage as shown in FIG. Since the oil is guided to the rolling surface of the ball, even if the ball rotates at high speed, it is possible to suppress the shortage of oil on the rolling surface and suppress the occurrence of seizure and wear.

In one aspect of the ball bearing according to the present invention, a plurality of the grooves extending in parallel are provided between the pockets adjacent in the circumferential direction, and the predetermined angle is 10 degrees or more and 70 degrees or less. , the depth of the recess in the radial direction of the groove is 0.5 mm or more and 5 mm or less, the width of the groove in the circumferential direction is 1 mm or more and 5 mm or less, and the grooves adjacent to each other between the pockets in the circumferential direction may be 1 mm or more and 20 mm or less.

According to this aspect, it is possible to suppress the shortage of the amount of oil on the rolling surface even when rotating at a high speed while suppressing the agitation resistance of the oil, thereby suppressing the occurrence of seizure and wear.

In one aspect of the ball bearing according to the present invention, the protrusions are provided on the outer peripheral surface and the inner peripheral surface of the retainer, and the direction in which the retainer rotates is the front side in the circumferential direction, and the opposite direction is the circumferential direction. As the rear side in the circumferential direction, the protruding portion may be arranged at a position along the hemispherical portion on the rear side in the circumferential direction of the ball, and may have a plate shape curved with a curvature along the hemispherical portion.

According to this aspect, due to the centrifugal force associated with the rotation of the cage, the plate-shaped protrusion curved along the rear hemispherical portion of the ball in the circumferential direction is brought into rolling contact with the outer raceway from the radially inner side of the cage. Since the oil is guided to the rolling contact surface, it is possible to suppress the shortage of the oil amount on the rolling contact surface and suppress the occurrence of seizure and wear even if the rolling contact surface rotates at high speed.

In one aspect of the ball bearing according to the present invention, the protrusion is curved with a curvature that secures a gap of 0.1 mm or more and 2 mm or less with the hemispherical portion when the protrusion is stopped. The radial length to the radial center position of the retainer is 1/5 or more and 1/3 or less of the diameter of the ball, and the width of the protrusion in the direction of the central axis is The thickness of the protrusion may be 1 mm or more and 5 mm or less, and may be 1/4 or more and 1/2 or less of the diameter of the ball.

According to this aspect, it is possible to suppress the shortage of the amount of oil on the rolling surface even when rotating at a high speed while suppressing the agitation resistance of the oil, thereby suppressing the occurrence of seizure and wear.

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.

It is the figure which expanded and showed a part of side surface of the ball bearing of 1st Embodiment. FIG. 2 is a cross-sectional view taken along line DD in FIG. 1; It is a figure which shows the shape which looked at the area|region drawn in FIG. 1 of the retainer from the radial outside. It is the figure which expanded and showed a part of side surface of the ball bearing of 2nd Embodiment. FIG. 5 is a cross-sectional view taken along line EE in FIG. 4; FIG. 5 is a view showing the shape of the area of the retainer depicted in FIG. 4 viewed from the outside in the radial direction; It is the figure which expanded and showed a part of side surface of the ball bearing of 3rd Embodiment. FIG. 8 is a cross-sectional view taken along line FF in FIG. 7; FIG. 8 is a view showing the shape of the area of the retainer depicted in FIG. 7 viewed from the outside in the radial direction; FIG. 10 is a cross-sectional view taken along line GG in FIG. 9; FIG. 3 is a side view of a ball bearing used in an evaluation test for observing the internal lubrication state; FIG. 12 is a sectional view taken along line AA in FIG. 11; It is the figure which expanded and showed a part of side surface of the ball bearing used for the evaluation test. FIG. 14 is a view showing a BB line cross section in FIG. 13 of the retainer; 14 is a cross-sectional view taken along the line CC in FIG. 13; FIG. It is a figure which shows the outline of the testing machine used for the evaluation test which observes the lubricating state inside a ball bearing. It is a figure which shows the observation area|region in the evaluation test which observes the lubricating state inside a ball bearing. 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.

<First Embodiment>
The ball bearing 20 of the first embodiment will be described below with reference to the drawings. FIG. 1 is an enlarged view showing a part of the side surface of the ball bearing 20, and FIG. 2 is a sectional view taken along line DD in FIG. As shown in FIGS. 1 and 2, the ball bearing 20 includes an outer ring 21, an inner ring 22, balls 23 and a retainer 25. As shown in FIG. The outer ring 21 and the inner ring 22 are annular members. An outer raceway 21a is formed on the inner peripheral surface of the outer ring 21 so as to follow the surfaces of the balls 23, which are rolling elements. An inner raceway 22 a is formed on the outer peripheral surface of the inner ring 22 so as to follow the surface of the ball 23 . The outer raceway 21a of the outer ring 21 and the inner raceway 22a of the inner ring 22 are provided at predetermined intervals along the circumferential direction of the annular ball bearing 20 . Ball 23 is held in a space formed by outer raceway 21a of outer ring 21 and inner raceway 22a of inner ring 22 in a rollable state. Moreover, the retainer 25 is arranged between the outer ring 21 and the inner ring 22, and holds the plurality of balls 23 at predetermined intervals in the circumferential direction so that they can roll. The ball bearing 20 rotates between the outer ring 21 and the inner ring 22 with the central axes of the outer ring 21 and the inner ring 22 as rotation axes (hereinafter simply referred to as axes) by rolling the balls 23 between the outer ring 21 and the inner ring 22 . are relatively rotatable.

FIG. 3 shows the shape of the area of the retainer 25 depicted in FIG. 1 viewed from the outside in the radial direction. Note that FIG. 3 also illustrates the balls 23 held by the retainer 25 . As shown in FIG. 3, one axial end of the retainer 25 is formed with a side surface 25a perpendicular to the axis, and a ball 23 is formed on the opposite side of the side surface 25a in the axial direction. A retaining pocket 24 is formed.

As shown in FIGS. 1, 2 and 3, projections 26 projecting in the radial direction are provided on the outer and inner peripheral surfaces of the retainer 25 . The projecting portion 26 extends in a direction that obliquely intersects the axial direction at a predetermined angle θ, and the angle θ is preferably 10 degrees or more and 70 degrees or less. A plurality of protrusions 26 extending in parallel are provided between the pockets 24 adjacent in the circumferential direction. The height H1 at which the protrusion 26 protrudes in the radial direction is preferably 0.5 mm or more and 5 mm or less. It is preferable that the thickness T1 of the protrusion 26 in the circumferential direction is 1 mm or more and 5 mm or less. A circumferential interval I1 between the adjacent protrusions 26 between the pockets 24 is preferably 1 mm or more and 20 mm or less.

The ball bearing 20 is used in applications where the rotation direction is mainly determined in one direction, such as a driving system unit for automobiles and machine tools. When the outer ring 21 is fixed and the inner ring 22 is rotated in the rotation direction mainly used, the balls 23 revolve toward the right side in FIG. to rotate. Hereinafter, by rotating the inner ring 22 in the direction of rotation mainly used in the ball bearing 20, the direction in which the retainer 25 rotates is defined as the front side in the circumferential direction (right side in FIG. 3), and the opposite direction is the rear side in the circumferential direction. (left side of FIG. 3).

As already described with reference to FIG. 19, if the projections 26 are not provided on the outer and inner peripheral surfaces of the retainer 25, when the inner ring 22 is rotated at a high speed, the oil will flow in the revolving raceway of the balls 23. It does not fill up, and a region of high oil concentration is formed near the side surface 25a of the retainer 25. As shown in FIG. However, in the ball bearing 20 in which the protrusions 26 are provided on the outer and inner peripheral surfaces of the retainer 25, when the retainer 25 rotates forward in the circumferential direction, the protrusions extending in the direction obliquely crossing the axial direction The portion 26 guides the oil from the area near the side surface 25 a where the oil concentration is high to the front side in the circumferential direction of the ball 23 , so that the oil is supplied to the rolling surface of the ball 23 . Therefore, even if the ball bearing 20 rotates at high speed, it is possible to suppress the shortage of the amount of oil on the rolling contact surface, and to suppress the occurrence of seizure and wear.

In order for the protrusion 26 to guide the oil in this manner, the height H1 of the protrusion 26 protruding in the radial direction must be of a certain size. increase. By setting the radial height H1 of the protrusion 26 to 0.5 mm or more and 5 mm or less as described above, the ball bearing 20 suppresses oil agitation resistance while allowing the protrusion 26 to move from the vicinity of the side surface 25 a to the ball 23 . It is possible to ensure the effect of guiding the oil to the rolling surface of the

In the ball bearing 20 of the present embodiment, both the outer peripheral surface and the inner peripheral surface of the retainer 25 are provided with the protrusions 26, but the protrusions 26 are provided on at least one of the outer peripheral surface and the inner peripheral surface. By providing it, at least one of the outer peripheral surface and the inner peripheral surface can enjoy the same effect as the ball bearing 20 .

<Second embodiment>
Next, the ball bearing 30 of 2nd Embodiment is demonstrated, referring drawings. The ball bearing 30 has the same configuration as the ball bearing 20 of the first embodiment, except that the grooves 36 are formed on the outer and inner peripheral surfaces of the retainer 35 instead of the protrusions 26. doing. Therefore, the same reference numerals are given to the same configurations as those of the ball bearing 20 of the first embodiment, and the description thereof is omitted.

4 is an enlarged view showing a part of the side surface of the ball bearing 30, and FIG. 5 is a cross-sectional view taken along line EE in FIG. As shown in FIGS. 4 and 5, the ball bearing 30 includes an outer ring 21, an inner ring 22, balls 23 and a retainer 35. As shown in FIG. FIG. 6 shows the shape of the area of the retainer 35 depicted in FIG. 4 viewed from the outside in the radial direction. Note that FIG. 6 also illustrates the balls 23 held by the retainer 35 . As shown in FIG. 6, a side surface 25a perpendicular to the axis is formed at one axial end of the retainer 35, and a ball 23 is formed on the opposite side of the axial direction from the side surface 25a. A retaining pocket 24 is formed.

As shown in FIGS. 4, 5 and 6, grooves 36 recessed in the radial direction are provided on the outer and inner peripheral surfaces of the retainer 35 . The groove 36 extends in a direction that obliquely crosses the axial direction at a predetermined angle φ, and the angle φ is preferably 10 degrees or more and 70 degrees or less. A plurality of grooves 36 extending in parallel are provided between the pockets 24 adjacent in the circumferential direction. The depth D2 of the recessed groove 36 in the radial direction is preferably 0.5 mm or more and 5 mm or less. The width W2 of the groove 36 in the circumferential direction is preferably 1 mm or more and 5 mm or less. A circumferential interval I2 between adjacent grooves 36 between pockets 24 is preferably 1 mm or more and 20 mm or less.

Like the ball bearing 20, the ball bearing 30 is also used in applications where the rotational direction is mainly determined in one direction, such as a driving system unit for automobiles and machine tools. When the outer ring 21 is fixed and the inner ring 22 is rotated in the rotation direction mainly used, the balls 23 revolve toward the right side in FIG. to rotate. Hereinafter, by rotating the inner ring 22 in the direction of rotation mainly used in the ball bearing 30, the direction in which the retainer 35 rotates is defined as the front side in the circumferential direction (right side in FIG. 6), and the opposite direction is the rear side in the circumferential direction. (left side of FIG. 6).

As already described with reference to FIG. 19, if the grooves 36 are not formed on the outer and inner peripheral surfaces of the retainer 35, when the inner ring 22 is rotated at high speed, the orbital portions of the balls 23 are filled with oil. Instead, a region of high oil concentration is formed near the side surface 25a of the retainer 35 . However, in the ball bearing 30 in which the grooves 36 are provided on the outer and inner peripheral surfaces of the retainer 35, when the retainer 35 rotates forward in the circumferential direction, the grooves 36 extending in the direction obliquely intersecting the axial direction are displaced. However, the oil is guided to the front side in the circumferential direction of the ball 23 from the area near the side surface 25 a where the oil concentration is high, and the oil is supplied to the rolling surface of the ball 23 . Therefore, even if the ball bearing 30 rotates at high speed, it is possible to suppress the shortage of the amount of oil on the rolling contact surface, and to suppress the occurrence of seizure and wear.

Further, in order for the grooves 36 to guide the oil in this way, the depth D2 of the grooves 36 in the radial direction needs to have a certain size. put away. By setting the depth D2 of the grooves 36 to 0.5 mm or more and 5 mm or less as described above, the ball bearing 30 suppresses the stirring resistance of the oil and allows the grooves 36 to extend from the vicinity of the side surfaces 25a to the rolling surfaces of the balls 23. The effect of inducing oil can be ensured.

In the ball bearing 30 of the present embodiment, the grooves 36 are provided on both the outer peripheral surface and the inner peripheral surface of the retainer 35, but the grooves 36 may be provided on at least one of the outer peripheral surface and the inner peripheral surface. Therefore, at least one of the outer peripheral surface and the inner peripheral surface can enjoy the same effect as the ball bearing 30 .

<Third Embodiment>
Next, the ball bearing 40 of 3rd Embodiment is demonstrated, referring drawings. The ball bearing 40 has the same configuration as the ball bearing 20 of the first embodiment, except that the guide plates 46 provided as protrusions on the outer and inner peripheral surfaces of the retainer 45 are different in number and shape. doing. Therefore, the same reference numerals are given to the same configurations as those of the ball bearing 20 of the first embodiment, and the description thereof is omitted.

FIG. 7 is an enlarged view showing a part of the side surface of the ball bearing 40, and FIG. 8 is a sectional view taken along line FF in FIG. As shown in FIGS. 7 and 8, the ball bearing 40 includes an outer ring 21, an inner ring 22, balls 23 and a retainer 45. As shown in FIG. FIG. 9 shows the shape of the area of the retainer 45 depicted in FIG. 7 viewed from the outside in the radial direction. Note that FIG. 9 also illustrates the balls 23 held by the retainer 45 . As shown in FIG. 9, a side surface 25a perpendicular to the axis is formed at one axial end of the retainer 45, and a ball 23 is formed on the opposite side of the axial direction from the side surface 25a. A retaining pocket 24 is formed. 10 is a cross-sectional view taken along the line GG in FIG. 9. FIG.

Like the ball bearing 20, the ball bearing 40 is also used in applications where the rotational direction is mainly determined in one direction, such as a driving system unit for automobiles and machine tools. When the outer ring 21 is fixed and the inner ring 22 is rotated in the rotation direction mainly used, the balls 23 revolve toward the right side in FIG. to rotate. Hereinafter, by rotating the inner ring 22 in the direction of rotation mainly used in the ball bearing 40, the direction in which the retainer 45 rotates is defined as the front side in the circumferential direction (right side in FIG. 9), and the opposite direction is the rear side in the circumferential direction. (left side of FIG. 9).

As shown in FIGS. 7, 8, 9 and 10, guide plates 46 are provided as protrusions radially protruding from the outer and inner peripheral surfaces of the retainer 45 . The guiding plate 46 is arranged at a position along the hemispherical portion 23a on the rear side in the circumferential direction of the ball 23, and has a plate shape curved with a curvature along the hemispherical portion 23a. As shown in FIG. 10, the guide plate 46 is preferably curved with a curvature that ensures a gap G3 of 0.1 mm or more and 2 mm or less between the guide plate 46 and the hemispherical portion 23a when the ball bearing 40 is stopped. A radial length L3 from the projecting tip of the guide plate 46 to the radial center position of the retainer 45 is preferably one-fifth or more and one-third or less of the diameter of the balls 23 . The width W3 of the guide plate 46 in the axial direction is preferably 1/4 or more and 1/2 or less of the diameter of the ball 23 . The thickness T3 of the guide plate 46 is preferably 1 mm or more and 5 mm or less.

When the outer ring 21 is fixed and the inner ring 22 is rotated forward in the circumferential direction, the balls 23 revolve forward in the circumferential direction, and the balls 23 push the cage 45 forward in the circumferential direction in the pockets 24. Therefore, the retainer 45 also rotates forward in the circumferential direction. As a result, contact between the wall surface of the pocket 24 and the ball 23 is greater between the wall surface on the rear side in the circumferential direction of the pocket 24 and the ball 23 than between the wall surface on the front side in the circumferential direction of the pocket 24 and the ball 23 . It becomes looser and the gap between the wall surface of the pocket 24 and the ball 23 becomes larger. Since a gap is formed between the wall surface of the pocket 24 on the rear side in the circumferential direction and the ball 23, a gap is also formed between the guide plate 46 and the ball 23. As shown in FIG. As a result, when the cage 45 rotates toward the front side in the circumferential direction in this way, the oil that has entered the gap between the guide plate 46 and the balls 23 on the radially inner side of the cage 45 will flow into the rotation of the cage 45 . The accompanying centrifugal force causes the balls 23 to move through the gaps between the balls 23 and the wall surface on the rear side in the circumferential direction of the pockets 24 and the gaps between the balls 23 and the guide plate 46 on the radially outer side of the retainer 45 . 23 is guided to the rolling surface in rolling contact with the outer raceway 21a.

Since the balls 23 are pressed toward the outer raceway 21a by the centrifugal force generated by the revolution, the radially outer rolling surface of the balls 23 is preferably arranged so that the oil is not depleted more than the radially inner rolling surface. need to be As described above, the guide plate 46 guides the oil to the radially outer rolling surface due to the centrifugal force associated with the rotation of the cage 45. Insufficient amount of oil on the moving surface can be suppressed, and the occurrence of seizure and wear can be suppressed.

In order for the guide plate 46 to guide the oil to the radially outer rolling surface in this way, the radial length L3 from the protruding tip of the guide plate 46 to the radial center position of the retainer 45, , the width W3 of the guide plate 46 in the axial direction needs to be large to some extent, but if it is too large, the oil agitation resistance increases. In the ball bearing 40, as described above, the length L3 is set to 1/5 or more and 1/3 or less of the diameter of the ball 23, and the width W3 is set to 1/4 or more and 1/2 or less of the diameter of the ball 23. As a result, the guide plate 46 can ensure the effect of guiding the oil to the radially outer rolling surface while suppressing the agitation resistance of the oil.

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 lubrication nozzle, 15 oil pump, 20, 30, 40 ball bearing, 21 outer ring, 21a outer raceway, 22 inner ring, 22a inner raceway, 23 ball, 23a semispherical portion, 24 pocket, 25, 35, 45 retainer, 25a side surface, 26 protrusion, 36 groove, 46 guide plate.

Claims (7)

an outer ring having an outer raceway formed on its radially inner surface; an inner ring having an inner raceway formed on its radially outer surface; a plurality of balls arranged between the outer raceway and the inner raceway; and an annular retainer formed with a plurality of pockets for holding the balls so that they can roll at intervals in the circumferential direction, wherein the outer ring and the inner ring are relatively rotatable about a central axis. a bearing,
At least one of the outer peripheral surface and the inner peripheral surface of the retainer is provided with radially projecting projections or radially recessed grooves,
A ball bearing, wherein the protrusions or the grooves guide oil to the rolling surfaces of the balls as the retainer rotates. A ball bearing according to claim 1,
The retainer has a side surface perpendicular to the central axis at one end in the direction of the central axis, and the pocket is formed on the opposite side of the side surface in the direction of the central axis,
The outer peripheral surface and the inner peripheral surface of the retainer are provided with the protrusion extending from the one end in a direction obliquely crossing the direction of the central axis at a predetermined angle. ball bearings. A ball bearing according to claim 2,
A plurality of the protrusions extending in parallel are provided between the pockets adjacent in the circumferential direction,
The predetermined angle is 10 degrees or more and 70 degrees or less,
The height at which the protrusion protrudes in the radial direction is 0.5 mm or more and 5 mm or less,
The thickness of the protrusion in the circumferential direction is 1 mm or more and 5 mm or less,
A ball bearing, wherein a circumferential interval between the adjacent protrusions between the pockets is 1 mm or more and 20 mm or less. A ball bearing according to claim 1,
The retainer has a side surface perpendicular to the central axis at one end in the direction of the central axis, and the pocket is formed on the opposite side of the side surface in the direction of the central axis,
The outer peripheral surface and the inner peripheral surface of the retainer are provided with the groove extending from the one end in a direction obliquely crossing the direction of the central axis at a predetermined angle. ball bearings. A ball bearing according to claim 4,
A plurality of the grooves extending in parallel are provided between the pockets adjacent in the circumferential direction,
The predetermined angle is 10 degrees or more and 70 degrees or less,
The depth of the recessed groove in the radial direction is 0.5 mm or more and 5 mm or less,
The width of the groove in the circumferential direction is 1 mm or more and 5 mm or less,
A ball bearing, wherein a circumferential interval between the grooves adjacent to each other between the pockets is 1 mm or more and 20 mm or less. A ball bearing according to claim 1,
The protrusions are provided on the outer peripheral surface and the inner peripheral surface of the retainer,
With the direction in which the retainer rotates and advances as the front side in the circumferential direction and the opposite direction as the rear side in the circumferential direction,
A ball bearing according to claim 1, wherein the protruding portion is arranged at a position along the hemispherical portion on the rear side in the circumferential direction of the ball, and has a plate shape curved with a curvature along the hemispherical portion. A ball bearing according to claim 6,
The protrusion is curved with a curvature that ensures a gap of 0.1 mm or more and 2 mm or less with the hemispherical portion when stopped,
The radial length from the projecting tip of the protrusion to the radial center position of the retainer is 1/5 or more and 1/3 or less of the diameter of the ball,
The width of the protrusion in the direction of the central axis is 1/4 or more and 1/2 or less of the diameter of the ball,
A ball bearing, wherein the projection has a thickness of 1 mm or more and 5 mm or less.

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