KR101789722B1 - Rolling bearing having a cage having improved rotational stability - Google Patents

Rolling bearing having a cage having improved rotational stability Download PDF

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Publication number
KR101789722B1
KR101789722B1 KR1020150168371A KR20150168371A KR101789722B1 KR 101789722 B1 KR101789722 B1 KR 101789722B1 KR 1020150168371 A KR1020150168371 A KR 1020150168371A KR 20150168371 A KR20150168371 A KR 20150168371A KR 101789722 B1 KR101789722 B1 KR 101789722B1
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South Korea
Prior art keywords
cage
dynamic pressure
inner ring
ring
outer ring
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KR1020150168371A
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Korean (ko)
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KR20170062780A (en
Inventor
이용복
최복성
곽원일
이전국
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한국과학기술연구원
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/38—Ball cages
    • F16C33/3806—Details of interaction of cage and race, e.g. retention, centring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
    • F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
    • F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/38—Ball cages
    • F16C33/3837—Massive or moulded cages having cage pockets surrounding the balls, e.g. machined window cages
    • F16C33/3843—Massive or moulded cages having cage pockets surrounding the balls, e.g. machined window cages formed as one-piece cages, i.e. monoblock cages

Abstract

The rolling bearing includes a cage for holding an inner ring, an outer ring, and a plurality of rolling members rolling between the inner ring and the outer ring, wherein when the inner ring or the outer ring rotates, friction between the inner ring and the outer ring, And wherein the cage includes a cage outer surface adjacent the inner surface of the outer ring and an inner surface of the cage adjacent the outer surface of the inner ring, wherein at least one of the outer surface of the cage and the inner surface of the cage Is formed with a dynamic pressure generating surface for generating a dynamic pressure in accordance with a wedge effect in a clearance between an inner side surface of the outer ring and an outer side surface of the inner ring and the center axis of the cage is coincident with the center axis of the inner ring A force is generated.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a rolling bearing having a cage having improved rotational stability,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing, and more particularly, to a rolling bearing in which the rotation stability of a cage for maintaining a spacing of a plurality of rolling elements rolling between rolling the inner and outer rings is increased.

In recent years, rotating machines have been downsized and energy capacity is increasing. Therefore, the rotational speed of the main shaft for generating the rotational force is gradually increasing, and the importance of the bearing as the high-speed rotational element is increasing.

Various types of bearings have been applied to rotating machines, for example, rolling bearings that support loads by rolling contact of rolling elements such as balls or rollers are among the relatively widely used bearings.

1 is an exploded perspective view of a rolling bearing 1 according to the prior art.

1, the rolling bearing 1 includes an outer ring 2, an inner ring 4 disposed on the inner side of the outer ring 2, and an inner ring 4 disposed on the inner side of the cage 6 between the outer ring 2 and the inner ring 4, And a plurality of rolling elements 8 spaced apart by a predetermined distance. The rolling bearing 1 shown in Fig. 1 is a ball bearing using a ball as the rolling member 8.

The outer ring 2 and the inner ring 4 are provided with rolling element accommodating grooves 3 and 5 on their inner and outer sides respectively and the plurality of rolling elements 8 are provided between the outer ring 2 and the inner ring 4 The clouds move.

The cage 6 includes a body in the shape of a ring and a plurality of rolling elements pockets 7 formed around the body for accommodating the rolling elements 8.

Generally, the high-speed ball bearing rotates with a rotation shaft (not shown) in which the inner ring 4 rotates, and the outer ring 2 is fixed to a frame or the like.

When the inner ring 4 is rotated by the rotating shaft, the cage 6 also rotates at a constant speed ratio with respect to the speed of the inner ring 4 due to the friction torque of the other ball bearing elements.

Particularly, in the case of a high-speed rotating machine, the rotation speed of the cage generally has a number of DN 1,000,000 (rotation axis diameter * RPM) or more, so that the rotation speed of the cage is about DN 400,000 or more. Equation 1 below expresses the number of revolutions of the cage 6 according to the rotation of the inner ring 4 numerically.

[Equation 1]

Figure 112015116576714-pat00001

Where rpm is the rotational speed of the rotating shaft, D is the diameter of the ball, dm is the average orbital diameter, and a is the contact angle.

Therefore, in the high-speed ball bearing, not only the dynamic relationship between the inner and outer rings and the ball but also the rotation stability of the cage plays a large role in the stability of the bearing.

A rolling bearing (1) Ideally, the center axis of the outer ring (O o), the center axis of the cage (O c) and the center axis of the inner ring (O c) the central axis (rotation axis) of the rotation axis (O) consistent with the And the most stable rotation stability is obtained when one state is maintained.

Fig. 2 shows the rotation state of the cage with respect to the rotational center axis O in the rolling bearing according to the prior art. This is analyzed because the cage 6 intermittently has an abnormal whirling motion and whirling rotation speed for various reasons such as intermittent collision of the cage and rolling elements.

As described above, although the cage plays an important role for the stable driving of the rolling bearings, the research and development on the structure of the cage which can directly cope with it is insufficient.

According to the prior art, a method of more flexible design of the cage pocket design itself is mainly used to improve the stability of the rotation stability of the cage, but this is a method of controlling the rigidity of the cage structure rather than using the rotational force.

Therefore, there is a high possibility that the cage will be damaged due to a decrease in the self-strength of the cage, and since the shape of the cage is complicated, the manufacturing cost may increase due to the difficulty of manufacture.

U.S. Patent No. 8,104,971

SUMMARY OF THE INVENTION It is an object of the present invention to provide a rolling bearing capable of increasing the stability of a cage by providing stiffness and damping in rotation of the cage using the rotational force of the cage.

According to an aspect of the present invention, there is provided a rolling bearing including an inner ring, an outer ring, and a cage for maintaining a gap between a plurality of rolling elements rolling between the inner ring and the outer ring, The rotation of the cage occurs due to the friction between the inner ring and the outer ring and the rolling member, and the cage is formed on the outer side of the cage adjacent to the inner side of the outer ring and the inner side of the cage Wherein at least one of the outer side surface of the cage and the inner side surface of the cage is provided with a dynamic pressure generating surface for generating a dynamic pressure in accordance with the wedge effect in a gap between the inner side surface of the outer ring and the outer side surface of the inner ring, A rolling bearing is provided in which a force is generated in a direction in which the center axis of the cage coincides with the center axis of the inner ring.

According to one embodiment, the dynamic pressure generating surface is formed by a curve connecting a circle point that is the farthest from the center axis of the cage and a proximal point closest to the radial distance from the center axis of the cage.

According to one embodiment, the cage of the rolling bearing includes a plurality of dynamic pressure generating surfaces, and the plurality of dynamic pressure generating surfaces are equally spaced radially about the central axis of the cage.

According to one embodiment, at least one of the outer side surface of the cage and the inner side surface of the cage is composed of a plurality of dynamic pressure generating surfaces smoothly connected to each other over the entire circumferential direction of the cage.

According to one embodiment, the cage is an outer ring closely-fitted cage having a distance from the outer ring to a distance from the inner ring, the dynamic pressure generating surface is formed on the outer surface of the cage, A force is generated in a direction of pushing out from the inner side surface of the frame.

According to one embodiment, the cage is an inner ring closely-fitted type cage having a distance from the inner ring to a distance from the inner ring, the dynamic pressure generating surface is formed on the inner side surface of the cage, A force is generated in a direction of pushing out from the outer side surface.

According to one embodiment, the inner side surface of the cage and the outer side surface of the cage extend in a direction parallel to the central axis of the cage.

1 is an exploded perspective view of a conventional ball bearing.
2 shows a rotation state of the cage with respect to the rotation center axis in the rolling bearing according to the prior art.
3 is a plan view of a rolling bearing according to an embodiment of the present invention.
Figure 4 is a perspective view of the cage of the rolling bearing of Figure 3;
5 is a plan view of a rolling bearing that exaggerates the cage of the rolling bearing of FIG.
Fig. 6 is a view for explaining the dynamic pressure acting on the rolling bearing of Fig. 3;
7 is a graph comparing the dynamic pressures of a cage according to an embodiment of the present invention and a conventional cage.
8 is a plan view of a rolling bearing according to another embodiment of the present invention.
9 is a plan view of a rolling bearing in which the cage of the rolling bearing of FIG. 8 is exaggerated.
Fig. 10 is a view for explaining the dynamic pressure acting on the rolling bearing of Fig. 8; Fig.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Although the present invention has been described with reference to the embodiments shown in the drawings, it is to be understood that the technical idea of the present invention and its essential structure and action are not limited by this embodiment.

3 is a plan view of a rolling bearing 10 according to an embodiment of the present invention. The rolling bearing 10 according to the present embodiment is a ball bearing using the ball 40 as a rolling body.

3, the rolling bearing 10 includes an inner ring 30, an outer ring 20, and a plurality of balls 40 rolling between the inner ring 30 and the outer ring 20, Cage < / RTI >

The inner side surface 32 and the outer side surface 31 of the inner ring 30 are both circular and the inner side surface 22 and the outer side surface 32 of the outer ring 20 are both circular.

The outer ring 20 and the inner ring 30 are each provided with a rolling member receiving groove on the inner and outer surfaces thereof so that the balls 40 roll between the outer ring 20 and the inner ring 30.

4 is a perspective view of the cage 100 of the rolling bearing 10 according to the present embodiment.

4, the cage 100 includes a cage outer side surface 110 adjacent to the inner side surface 22 of the outer ring 20 and a cage inner side surface 116 adjacent to the outer side surface 31 of the inner ring 30. [ And includes a side surface 120. Between the cage outer surface 110 and the inner side surface 120 of the cage is formed a cage upper surface 140 and a cage upper surface 150 which extend in the radial direction of the cage 10. [

According to the present embodiment, the inner side surface, the outer side surface, the upper surface and the lower surface forming the outer surface of the cage 100 are all formed in a flat shape. In the cage 100, a plurality of rolling element pockets 160 are formed along the circumference of the body to receive the balls 40.

The cage according to the embodiments of the present invention may employ a lobe structure on the inner side and / or outer side for dynamic pressure formation and augmentation as described later, . Therefore, the rigidity of the cage can be maintained as it is compared with the conventional technique such as changing the shape of the pocket.

Referring again to FIG. 3, the cage outer surface 110 of the cage 100 and the inner surface 22 of the outer ring 20 are spaced apart from each other by a predetermined distance, and an outer gap 11 is formed therebetween. The inner side surface 120 of the cage 100 and the outer side surface 31 of the inner ring 30 are spaced apart from each other by a predetermined distance and an inner gap 12 is formed therebetween.

The cage 100 according to the present embodiment has a smaller distance from the outer ring 20 than the inner ring 30 (i.e., the width of the inner gap 12) (i.e., the width of the outer gap 11) It is an outer ring close type cage.

The inner ring 30 and the outer ring 20 each have a center axis corresponding to the center of gravity (or center of rotation) of the cage 100 and the cage 100 has a center axis (or center of rotation) O c ) (see FIG. 4).

The center of the case that the rotating force exerted on the bearing 10 the inner ring 30, the central axis (O i), the outer ring 20, a center axis, and the cage 100 in the center axis (O c), all bearing 10 of the Is formed so as to coincide with the axis (O).

According to the present embodiment, the bearing 10 rotates with a rotation shaft (not shown) in which the inner ring 30 rotates, and the outer ring 20 is fixed to a frame or the like. It should be understood, however, that the bearing may operate in a form in which the inner ring 30 is fixed and the outer ring 20 is rotated in rare cases, and that the technical idea of the present invention can be applied to a configuration in which the outer ring 20 rotates .

Friction occurs between the inner ring 30 and the outer ring 20 and the ball 40 when the inner ring 30 is rotated by the rotating shaft and the cage 100 is moved in the same direction as the inner ring 30 So that it rotates at a constant speed. This also applies to the case where the outer ring 20 rotates.

Ideally, the central axis (O c) is and kept at the same position as the central axis (O i) (i.e., the central axis (O) of the bearing) of the inner ring 30, a cage 100, a rotation of the cage 100 The rotation stability is good. However, as described above, during the rotation process, the cage 100 can intermittently perform an unusual whirling motion.

According to the present embodiment, in order to prevent the vortical motion and ensure the stability of rotation, the cage 100 applies a dynamic pressure to the clearance 11 of the inner side surface 22 of the outer ring 20 having a relatively smaller gap Pressure generating surface 130 for generating a pressure.

5 is a plan view of the cage 100 according to the present embodiment. It should be understood that the shape of the cage 100 is shown exaggerated in FIG. 5 to illustrate the dynamic pressure generating surface 130.

5, the dynamic pressure generating surface 130 is formed on the cage outer surface 110 of the cage 100. As shown in Fig.

The cage outer surface 110 is not in the form of a circle having the center axis O c of the cage 100 as its origin but has a radius r 1 that is the longest distance from the center axis O c And three lobe shapes in which three circle points 131 exist. The radial distances r 1 from the center to the respective origin points 131 are the same so that the three origin points 131 are located on the distal circle 140 with the center axis O c of the cage 100 as the origin It is a point.

Between two adjacent origin points 131, a proximal point 132 having a radius (r 2 ) of the shortest distance relative to the other portion is formed. The proximal point 132 is disposed inside the distal circle 140.

The dynamic pressure generating surface 130 is formed by a curve smoothly connecting the distal point 131 and the proximal point 132. The curvature of the curve forming the dynamic pressure generating surface 130 can be appropriately adjusted in consideration of the number of revolutions and the size of the bearing.

The cage outer surface 110 according to this embodiment has a shape in which the radial distance is different for each part by the dynamic pressure generating surface 130, but the extending direction thereof is parallel to the central axis O c of the cage. That is, the width of the clearance 11 in the longitudinal direction of the cage does not become narrow or wide. The cage inner side surface 110 also extends parallel to the center axis O c of the cage and the upper surface 140 and the lower surface 150 of the cage are formed parallel to each other. The outer surfaces of the cages facing each other are formed parallel to each other so that the smooth flow of the working fluid such as lubricant passing through the bearing 10 is prevented by the lobe type cage.

According to the present embodiment, the three origin points 131 and the three proximal points 132 are equally spaced radially with the same angular difference with respect to the central axis O c of the cage 100.

A plurality of dynamic pressure generating surfaces 130 connecting these points are formed and the plurality of dynamic pressure generating surfaces are radially and equally spaced about the center axis O c of the cage 100.

According to the present embodiment, the cage outer surface 110 is formed by connecting a plurality of the dynamic pressure generating surfaces 130 to each other and smoothly connecting the plurality of dynamic pressure generating surfaces 130 to each other in the circumferential direction of the cage 100 Thereby forming a cage outer surface 110 of a smooth curve. The curve formed by the dynamic pressure generating surface 130 has no inflection point between the proximal point 132 and the distal point 131. [ Accordingly, as shown in Fig. 5, the cage outer surface 110 is curved in a generally convex shape radially outwardly of the cage, without a radially inwardly depressed portion of the cage.

The lobe-shaped cage outer surface 110 maximizes a so-called "wedge effect " in which a fluid such as air or lubricant is drawn into a small gap 11 with the inner surface 22 of the outer ring 20 to form an oil film, This wedge effect of the oil film generates dynamic pressure in the gap (11).

6 is a view for explaining the dynamic pressure acting on the bearing 10 according to the present embodiment.

If, the inner ring 20 is rotated at a high speed with the center axis (O i) in one direction relative to (that is, the central axis of the bearing) (R) of the inner ring 20 by the rotation of the rotating shaft 6, the The cage 100 also rotates in the same direction at a constant speed. At this time, it is ideal in terms of rotation stability that the center axis O c of the cage 100 rotates in the state of coinciding with the center axis O i of the inner ring 20.

The wedge effect is maximized by the action of the tilted surface of the dynamic pressure generating surface 130 leading from the origin point 131 to the proximal point 132 and an oil film is formed in the gap 11 to generate the dynamic pressure P do.

The dynamic pressure P is distributed and distributed along the dynamic pressure generating surface 130 from the maximum dynamic pressure point at which the force F is maximum and the cage 100 is moved by the dynamic pressure P to the inside surface of the outer ring 20 A force is generated in a direction of pushing out from the base 22.

7 is a graph comparing the dynamic pressure of the cage 100 according to the present embodiment and the cage according to the prior art. In Fig. 7, the dotted line indicates the case of the cage according to the present embodiment, and the solid line indicates the case of using the cage according to the prior art.

Referring to FIG. 7, it can be seen that a predetermined dynamic pressure is generated as the number of revolutions increases, even if a circular cage according to the related art is used. However, the dynamic pressure is very small and increases in proportion to the number of revolutions There is practically no width. Therefore, it can be seen that almost no dynamic pressure is generated for ensuring the stability of rotation.

On the other hand, according to the cage 100 of the lobe structure according to the present embodiment, a large dynamic pressure is generated even when the number of revolutions is low, and the magnitude of the dynamic pressure is greatly increased as the number of revolutions increases.

6, the maximum dynamic pressure point at which the dynamic pressure P becomes maximum is slightly shifted to the side of the rotational direction R of the bearing at the position of the circle 131 at which the size of the gap 11 is minimum. And the magnitude of the dynamic pressure P becomes smaller toward the proximal point 132. [

As shown in FIG. 6, the dynamic pressure P occurs over the entire circumferential direction of the cage outer surface 110 in consideration of the positions of the three origin points 131.

When the center axis O c of the cage 100 coincides with the center axis O i of the inner ring due to the structural symmetry of the cage 100, the dynamic pressure P Have substantially the same size and distribution.

The rotation of the cage 100 occurs due to the intermittent collision of the cage 100 and the rolling member during rotation so that the center axis O c of the cage 100 is positioned at the position of the center axis O i of the inner ring 100 . At this time, the magnitude of the dynamic pressure distributed at the position of the gap 11 reduced by the center movement of the cage 100 increases, and the cage 100 is pushed out from the inner side surface 22 of the outer ring 20 The force increases in the direction. On the other hand, since the gap is increased on the opposite side, the pushing force decreases as the dynamic pressure decreases. The change in the magnitude and distribution of the dynamic pressure causes a force in the direction of aligning the center axis O c of the cage 100 with the center axis O i of the inner ring, c is returned to coincide with the center axis O i of the inner ring.

Such a dynamic pressure action provides a damping effect that allows the geometric center of the cage 100 to be the same as the center of the bearing and the stable whirling without bias.

The cage 100 according to the present embodiment has a rigidity that restores the center of mass of the cage to the center of the bearing by using the rotational force, unlike the prior art in which the stability of rotation of the cage is secured by utilizing the structural stiffness of the cage, Since damping is provided, the rotation stability of the cage can be maximized.

8 is a plan view of a rolling bearing 10 'according to another embodiment of the present invention.

8, the rolling bearing 10 'maintains the spacing of the rolling balls 40 between the inner ring 30, the outer ring 20, and the inner ring 30 and the outer ring 20 (Not shown).

The cage outer surface 210 of the cage 200 and the inner surface 22 of the outer ring 20 are spaced apart from each other by a predetermined distance and an outer gap 11 is formed therebetween. The inner side surface 220 of the cage 200 and the outer side surface 31 of the inner ring 30 are spaced apart from each other by a predetermined distance and an inner gap 12 is formed therebetween.

The cage 200 according to the present embodiment is configured such that the distance from the inner ring 30 (i.e., the width of the outer gap 12) is shorter than the distance from the outer ring 20 (i.e., the width of the outer gap 11) It is an inner ring close type cage.

The inner ring 30 and the outer ring 20 each have a central axis corresponding to the center of gravity (or center of rotation) of the cage 200 and the cage 200 has a center axis (or center of rotation) O c ).

Friction between the inner ring 30 and the outer ring 20 and the ball 40 occurs when the inner ring 30 is rotated by the rotary shaft and the cage 200 is caused to rotate in the same direction as the inner ring 30 So that it rotates at a constant speed. This also applies to the case where the outer ring 20 rotates.

According to the present embodiment, the cage 200 includes a dynamic pressure generating surface 230 that generates dynamic pressure in the gap 12 with the outer surface 31 of the inner ring 30 having a relatively smaller gap.

9 is a plan view of the bearing 10 'according to the present embodiment. It should be understood that the shape of the cage 200 is shown exaggerated in FIG. 9 to illustrate the dynamic pressure generating surface 230.

9, a dynamic pressure generating surface 230 is formed in the cage inner surface 220 of the cage 200. As shown in Fig.

The cage inner side surface 220 is not in the form of a circle with the origin O c of the cage 200 but has a radius r 1 that is the longest distance from the center axis O c And three lobe shapes in which three circle points 231 exist.

Between two adjacent origin points 231, a proximal point 232 having a radius (r 2 ) of the shortest distance relative to the other portion is formed. The radial distance r 2 from the center to each proximal point 232 is the same so that the three proximal points 232 are located on one of the proximal circles 240 originating at the center axis O c of the cage 200 It is a point. The origin point 231 is disposed outside the proximal circle 240.

The dynamic pressure generating surface 230 is formed by a curve smoothly connecting the distal point 231 and the proximal point 232. The curvature of the curve forming the dynamic pressure generating surface 230 can be appropriately adjusted in consideration of the number of revolutions and the size of the bearing.

According to the present embodiment, three distal points 231 and three proximal points 232 are equally spaced radially with the same angular difference with respect to the central axis O c of the cage 200.

A plurality of dynamic pressure generating surfaces 230 are formed so as to connect these points and the plurality of dynamic pressure generating surfaces are radially and equally spaced about the central axis O c of the cage 200.

According to the present embodiment, when the inner side surface 220 of the cage is formed by connecting the plurality of the dynamic pressure generating surfaces 230, the plurality of dynamic pressure generating surfaces 230 smoothly spread along the entire circumferential direction of the cage 200, Thereby forming a curved inner side surface 210 of the cage.

This lobe-shaped cage inner surface 220 maximizes the wedge effect with a small gap 12 with the outer surface 31 of the inner ring 30 to generate dynamic pressure in the gap 12.

10 is a view for explaining the dynamic pressure acting on the bearing 10 'according to the present embodiment.

If, the inner ring 20 is rotated at a high speed with the center axis (O i) in one direction relative to (that is, the central axis of the bearing) (R) of the inner ring 20 by the rotation of the rotary shaft 10, the The cage 200 also rotates in the same direction at a constant speed. At this time, it is ideal in terms of rotation stability that the center axis O c of the cage 200 rotates in the state of being coincident with the center axis O i of the inner ring 20.

The wedge effect is maximized by the action of the tilted surface of the dynamic pressure generating surface 130 leading from the origin point 231 to the proximal point 232 and an oil film is formed in the gap 12 to generate a dynamic pressure P .

The dynamic pressure P is distributed and distributed along the dynamic pressure generating surface 230 from the maximum dynamic pressure point at which the force F is maximized and the cage 200 is fixed to the outer surface of the inner ring 30 A force is generated in a direction of pushing out from the base 31.

The maximum dynamic pressure point at which the dynamic pressure P is maximized is formed at a position shifted slightly laterally along the rotational direction R of the bearing at a position 231 at which the size of the gap 12 is minimum, P becomes smaller toward the proximal point 232.

The dynamic pressure P is generated in the entire circumferential direction of the inner side surface 220 of the cage in consideration of the positions of the three circle points 231. [

The rotation of the cage 200 occurs due to the intermittent collision of the cage 200 and the rolling member during rotation so that the center axis O c of the cage 200 is located at the position of the center axis O i of the inner ring The size of the dynamic pressure distributed at the position of the gap 12 reduced by the center movement of the cage 200 is increased so that the cage 200 is pushed from the outer side surface 31 of the inner ring 30 at the corresponding portion The force increases in the direction of release. On the other hand, since the gap is increased on the opposite side, the pushing force decreases as the dynamic pressure decreases. This change in the magnitude and distribution of the dynamic pressure causes a force in the direction of aligning the center axis O c of the cage 200 with the center axis O i of the inner ring, c is returned to coincide with the center axis O i of the inner ring.

This dynamic pressure action provides a damping effect that allows the geometric center of the cage 200 to be the same as the center of the bearing and the stable whirling without bias.

Claims (7)

A rolling bearing comprising an inner ring, an outer ring, and a cage for maintaining a spacing of a plurality of rolling elements rolling between the inner ring and the outer ring,
When the inner ring or the outer ring rotates, rotation of the cage occurs due to friction between the inner ring and the outer ring and the rolling member,
Wherein the cage includes a cage outer surface adjacent to the inner surface of the outer ring and an inner surface of the cage adjacent to the outer surface of the inner ring,
Wherein at least one of the outer surface of the cage and the inner surface of the cage is provided with a dynamic pressure generating surface for generating a dynamic pressure in accordance with a wedge effect in a gap between an inner surface of the outer ring and an outer surface of the inner ring, A force is generated in a direction in which the central axis coincides with the central axis of the inner ring,
Wherein the dynamic pressure generating surface is formed by a curve connecting a circle point which is the farthest from the center axis of the cage in the radial direction and a proximal point closest to the radial distance from the center axis of the cage,
Wherein at least one of the outer side surface of the cage and the inner side surface of the cage is provided with a plurality of dynamic pressure generating surfaces smoothly extending along the entire circumferential direction of the cage,
Wherein the curve forming the dynamic pressure generating surface has no inflection point between the proximal point and the origin point. delete The method according to claim 1,
Wherein the plurality of dynamic pressure generating surfaces are equidistantly disposed radially about a center axis of the cage. delete The method according to claim 1,
Wherein the cage is an outer ring closely fitted type cage having a distance from the outer ring to a distance from the inner ring,
Wherein the dynamic pressure generating surface is formed on the outer surface of the cage,
And a force is generated in the direction pushing the cage from the inner side of the outer ring by the dynamic pressure. The method according to claim 1,
Wherein the cage is an inner ring closely-fitted type cage having a distance from the inner ring to the outer ring,
Wherein the dynamic pressure generating surface is formed on an inner side surface of the cage,
And a force is generated in the direction pushing the cage from the outer side surface of the inner ring by the dynamic pressure. The method according to claim 1,
Wherein the inner side surface of the cage and the outer side surface of the cage extend in a direction parallel to the central axis of the cage.
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Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2014095442A (en) * 2012-11-09 2014-05-22 Seiko Instruments Inc Retainer, rolling bearing, and dental handpiece

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JP2014095442A (en) * 2012-11-09 2014-05-22 Seiko Instruments Inc Retainer, rolling bearing, and dental handpiece

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