JP2003239986A - Ball bearing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a ball bearing in which noise of a cage, vibration, and torque are reduced, and acoustic durability is improved. <P>SOLUTION: This ball bearing is provided with an outer ring having an outer ring track on an inner peripheral face, an inner ring having an inner ring track on an outer peripheral face, a plurality of balls provided between the outer ring track and the inner ring track so as to roll freely, and the cage retaining a plurality of balls so as to roll freely. Grease is filled into a space between the outer ring track and the inner ring track. An inner peripheral face of a pocket of the cage is constituted by a spherical face part composed of a spherical recessed face having radius of curvature slightly larger than radius of curvature of a ball and a curved face part which has radius of curvature larger than the spherical face part and is smoothly continuous toward an end fringe on an opening side of each pocket from an end fringe of the spherical face part. Radius of curvature of a cross sectional shape of the inner ring track and radius of curvature of a cross sectional shape of the outer ring track are less than 51.0 to 60.0% of an outside diameter of a rolling element. Radius of curvature of the cross sectional shape of the outer ring track is not less than radius of curvature of the cross sectional shape of the inner ring track. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ball bearing for various motors used in general industry, and more particularly to a ball bearing designed to reduce cage noise, lower vibration, lower torque, and improve acoustic durability. Regarding

[0002]

2. Description of the Related Art For general industrial use, for example, a drive motor device for an air conditioner (hereinafter referred to as "air conditioner") can be mentioned. In recent years, this air conditioner has advanced in performance and has become multifunctional. For example, by inverter control, after rapidly cooling by high-speed operation and lowering the room temperature in a short time, the room temperature is kept constant by low-speed operation. Is being done. Along with this, at low speed operation, there is a demand for low noise operation in which air blowout noise, motor rotation noise, etc. are suppressed. However, during low-speed operation, the cooling efficiency inside the device decreases and the temperature of the rolling bearing incorporated in the motor may rise to around 100 to 120 ° C, and it becomes difficult to secure the oil film thickness by lubrication, and it is enclosed in the bearing. The grease that has formed is likely to deteriorate. Then, as the deterioration progresses, noise is generated.

In an outdoor unit used for an air conditioner, the bearing initial sound (retainer sound) at the time of starting operation in a low temperature environment such as winter may be a problem.

On the other hand, in consideration of environmental regulations as well as the above-mentioned high performance and multi-functionality, miniaturization and low output have been promoted in order to suppress heat generation from the motor. For this reason,
In rolling bearings used for these purposes, torque characteristics are required as an important function. The dynamic friction torque of the rolling bearing is generated due to the friction due to minute slip on the rolling contact surface, the sliding friction at the sliding contact portion in the bearing, and the viscous resistance of grease. It is known that the viscosity resistance of grease is influenced by the kinematic viscosity of the base oil and the consistency of the grease. Therefore, since the kinematic viscosity of the base oil depends on the shearing resistance of the oil when the fluid lubricating film is formed, the reduction of this kinematic viscosity is a great solution for reducing the dynamic friction torque of the rolling bearing. Further, since the consistency of grease is related to the channeling property when the bearing is sheared inside the bearing during rotation, it is also effective to reduce the consistency.

However, if the kinematic viscosity of the base oil is reduced, as described above, the motor of the air conditioner may be operated at a relatively low speed due to the inverter control, which makes it difficult to secure the oil film thickness. In addition, oils having a low kinematic viscosity generally have low heat resistance, which causes a problem in acoustic durability. On the other hand, reducing the consistency of grease leads to an increase in the amount of the thickener compounded, so the amount of base oil in the grease is relatively small, and the mechanical shear resistance of the grease increases, As a result, the amount of base oil supplied to the bearing lubricated surface is reduced, and it becomes impossible to maintain the lubricity stably for a long period of time.

As described above, there is a limit to the reduction of the base oil kinematic viscosity and the grease consistency, and in the rolling bearing for the above-mentioned use, the base oil kinematic viscosity at 40 ° C. is 10 to 500 mm ² /
s, grease having a consistency of NLGI No. 2 to 3 grade, or a grease having a thickening agent content of 5 to 20% by mass is suitable. Further, particularly in a motor that requires low noise characteristics, that is, acoustic durability, a polar group-containing lubricating oil or a mixed oil of this polar group-containing lubricating oil and a non-polar lubricating oil is used as a base oil, and a fatty acid is used as the base oil. A grease containing a lithium salt as a thickener is used. As the polar group-containing lubricating oil, ester oil or ether oil is generally used. Ester oils and ether oils have higher heat resistance than non-polar lubricating oils (for example, mineral oils) and have polar groups in their molecular structure. These polar groups increase the adsorptivity to the metal surface and cause wear. It has the effect of improving the characteristics and improving the acoustic durability.

On the other hand, a ball bearing as shown in FIG. 1, for example, is known as a rolling bearing used for the above-mentioned purpose.
In this ball bearing, an inner ring 2 having an inner ring raceway 1 on the outer peripheral surface and an outer ring 4 having an outer ring raceway 3 on the inner peripheral surface are concentrically arranged, and a plurality of ball races are provided between the inner ring raceway 1 and the outer ring raceway 3. 5 and 5 are provided so that they can roll freely. In the case of the illustrated example, both the inner ring raceway 1 and the outer ring raceway 3 are deep groove type. Also, balls 5, 5
Are rotatably held in pockets 7, 7 provided in the cage 6.

The cage 6 is called a corrugated press cage, and is formed by combining a pair of corrugated and annularly formed elements 8, 8 each of which is formed by press-molding a metal plate material. Become. These two elements 8 and 8 have recesses 9 and 9 of substantially semi-cylindrical shape for forming the pockets 7 and 7 at a plurality of positions in the circumferential direction.
Then, the pair of elements 8, 8 are connected to each of the recesses 9,
9 are abutted with each other, and these parts are joined and fixed by a plurality of rivets 10 to form an annular cage 6 having pockets 7, 7 at a plurality of circumferential positions.
In addition, the inner surface middle portion of each recess 9, 9 is a spherical concave surface having an arc-shaped cross section having a radius of curvature slightly larger than the radius of curvature of the outer surface of each ball 5, 5. Therefore, the pair of elements 8,
When 8 is abutted, the recesses 9 and 9 are combined to form pockets 7 and 7.

When the ball bearing is used, relative rotation between the inner ring 2 and the outer ring 4 is allowed as the balls 5 and 5 roll. At that time, the balls 5 and 5 revolve around the inner ring 2 while rotating. The cage 6 rotates around the inner ring 2 at the same speed as the revolution speed of each ball 5, 5.

A lubricant such as grease or other lubricating oil is filled or continuously supplied to a portion between the outer peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 4 to smoothly perform the above relative rotation. Is done. In addition, vibration and noise are prevented from occurring in the ball bearing, and trouble such as seizure is prevented. In a ball bearing for an air conditioner, a sealing member such as a seal plate or a shield plate closes both end openings of the space between the outer peripheral surface of the inner ring 2 and the inner peripheral surface of the outer ring 4, and the lubricant leaks from this space. In some cases, foreign matter such as dust may be prevented from entering the space. However, FIG. 1 shows a ball bearing without such a sealing member.

[0011]

By the way, in the case of the above-mentioned ball bearing, even if a necessary amount of lubricant is filled or supplied, vibration is induced in the cage 6 and the ball bearing has a noise called cage noise. Or vibration may occur. Such a vibration of the cage 6 occurs due to a large amount of movement of the cage 6 with respect to the balls 5 and 5, based on sliding friction between the balls 5 and 5 and the cage 6. Therefore, conventionally, by reducing the gap between the inner surfaces of the pockets 7, 7 and the rolling surfaces of the balls 5, 5 to reduce the movement amount of the cage 6 with respect to the balls 5, 5, the cage noise is reduced. Occurrence is suppressed.

However, even if the amount of movement of the cage 6 with respect to the balls 5 and 5 is simply reduced, when the operating conditions are severe, such as when the supply of the lubricant is insufficient, the pockets 7 of the cage 6 are Cage noise may occur due to the shape of the inner peripheral surface of No. 7. That is, in the conventional cage 6 shown in FIG.
Since the inner peripheral surfaces of the pockets 7, 7 can come into sliding contact with the rolling surfaces of the balls 5, 5 over substantially the entire width thereof, the frictional force acting between these inner peripheral surfaces and the rolling surfaces becomes large. . This point will be described in more detail with reference to FIGS. 7 and 8.

First, in the case of the conventional structure shown in FIG. 1, as for the inner peripheral surface of the pockets 7, 7, as shown by the slanted lattices in FIGS. 7 and 8, most of the concave portions 9, 9 are in the entire width thereof. Well, ball 5,
5 (FIGS. 1 and 10) are spherical portions 15, 15 functioning as holding guide surfaces having a radius of curvature slightly larger than the radius of curvature of the rolling surface of FIG. In this way, pockets 7, 7
If the inner peripheral surface of each of the pockets 15 is a spherical portion 15 that functions as a holding guide surface over its entire width, the friction area between the inner peripheral surface of each pocket 7, 7 and the rolling surface of each ball 5, 5 is Becomes wider,
The frictional vibration generated at the sliding contact portion between the cage 6 and the balls 5 and 5 becomes large, and induces vibration and noise. When the pockets 7, 7 are spherical portions 15, 15 that are single spherical surfaces over the entire width thereof, the center O ₁₅ (FIG. 10) of the spherical portions 15, 15 of these pockets is , the center O ₅ (FIG. 10 of balls 5 held in each pocket 7, 7, 1
In the case of deviation from 1), the lubricant adhering to the rolling surfaces of the balls 5 and 5 is scraped off, and the vibration and noise become remarkable.
This point will be described in detail with reference to FIGS. 9 to 11 using the corrugated press holder as shown in FIG. 1 as an example.

In the conventional cage 6, as shown in FIG. 9, the radius of curvature R ₁₅ of the spherical portion 15 forming each pocket 7, 7 is slightly larger than the radius of curvature R ₅ of the ball 5 (R ₁₅ >. R
₅ ) It was a single spherical surface. Moreover, one half of the inner dimension of the cage 6 the width direction for each pocket 7, 7, these depth D ₇ of each pocket 7, 7, as shown in exaggerated in Figure 10, the spherical portion 15 It was slightly smaller than the radius of curvature R _{15 of} .

In a ball bearing incorporating such a retainer 6, the rolling surface of each ball 5 and the inner peripheral surface of each pocket 7 provided in the retainer 6 abut each other during operation, and each of these balls 5 is While rotating, it revolves at the same speed as the cage 6. However, each ball 5 has a shape error of the inner ring raceway 1 and the outer ring raceway 3 (FIG. 1),
Or, the revolution speeds of all the balls 5 do not completely match due to the mutual difference of the balls 5 themselves and the inclination of the ball bearings (deviation of the central axes of the inner ring 2 and the outer ring 4), and each ball 5 has a very small revolution speed. It causes delays and advances. As a result, between each ball 5 and the cage 6, there are a case where the ball 5 pushes the cage 6 in the revolving direction and a case where the cage 6 pushes the ball 5 conversely. In each case, ball 5
The rolling surface of is in contact with the spherical surface portion 15 forming the inner peripheral surface of the pocket 7. That is, the radius of curvature R of each of these spherical surfaces 15
₁₅ is greater than the radius of curvature R ₅ of each ball 5, the retainer 6, as shown in FIG. 10, these curvature radii R _15, R ₅
It is displaced in the radial direction by the gap based on the difference of. Then, in this state, the rolling surface of each ball 5 and the spherical surface portion 15 forming each pocket 7 are in sliding contact with each other. That is, in this state, as shown in FIGS. 10 and 11, the spherical surface portion 15 and the rolling surface of the ball 5 which form each pocket 7 are arranged in the width direction of the cage 6 (vertical direction in FIG. 10, FIG. 11). On both sides (in the left-right direction), sliding contact is made at two points P ₁ and P ₂ that are displaced from the central portion in the circumferential direction of the pocket 7 toward the end portion in the circumferential direction.

Based on the gap resulting from the difference between the radii of curvature R ₁₅ and R ₅ , the center O ₇ of the pocket 7 of the retainer 6 is
As shown in 1, when shifted to the inner diameter side from the center O ₅ of the ball 5, of the rolling surface of the balls 5, constituting an outer径寄Ri portion of the retainer 6, the inner peripheral surface of the pocket 7 The portion of the spherical surface portion 15 that is in contact with the outer diameter portion of the cage 6 slides. Therefore, the lubricant such as grease or oil that is supplied to lubricate the ball bearings and adheres to the rolling surface of each ball 5 is scraped off at the edge of the spherical surface portion 15, and this lubricant is stored in each pocket 7. It is pushed out of the pocket 7 without being taken in by. Further, on the opposite side in the circumferential direction of the cage 6, of the rolling surface of the ball 5, the portion closer to the inner diameter of the cage 6 and the spherical portion 15 forming the inner circumferential surface of the pocket 7 closer to the inner diameter of the cage 6. The phenomenon of sliding contact with the part occurs, and also the intake failure of the lubricant occurs.

As a result of such a poor lubricant intake, the sliding friction coefficient of the sliding contact portion between the rolling surface of each ball 5 and the spherical surface portion 15 forming the inner peripheral surface of the pocket 7 of the cage 6 becomes large. To increase. As a result, the friction torque of the ball bearing in which the cage 6 is incorporated fluctuates or increases, and further, a friction noise is generated during operation, and in some cases, this friction noise becomes remarkable.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a ball bearing in which reduction of cage sound, reduction of vibration, reduction of torque and improvement of acoustic durability are achieved. And

[0019]

In order to achieve the above object, the present invention provides an outer ring having an outer ring raceway on an inner peripheral surface, an inner ring having an inner ring raceway on an outer peripheral surface, and an outer ring raceway and an inner ring raceway. In a ball bearing having a plurality of balls rotatably provided in and a retainer for rotatably holding the plurality of balls, wherein grease is sealed in the space between the outer ring raceway and the inner ring raceway, The inner peripheral surface of the pocket of the cage has a spherical surface portion formed of a spherical concave surface having a radius of curvature slightly larger than the radius of curvature of the ball, and has a larger radius of curvature than the spherical surface portion, and an edge of the spherical surface portion. From the curved surface portion that is smoothly continuous toward the opening side edge of each pocket, the radius of curvature of the cross-sectional shape of the inner ring raceway and the radius of curvature of the cross-sectional shape of the outer ring raceway, Outer diameter 51.0 to 60.0
%, And the radius of curvature of the cross-sectional shape of the outer ring raceway is not less than the radius of curvature of the cross-sectional shape of the inner ring raceway.

[0020]

In the cage constructed as described above, the inner peripheral surface of each pocket and the rolling surface of the ball rub against each other only on the spherical surface portion, but not on the curved surface portion. Further, a gap larger than the gap existing between the spherical surface portion and the ball rolling surface exists between the curved surface portion and the ball rolling surface. Therefore, not only the friction area between the inner peripheral surface of each pocket and the rolling surface of the ball is reduced, but also the lubricant is smoothly taken into the gap portion existing between the spherical surface portion and the rolling surface, which is effective. Will be performed. By these actions, the friction acting on the sliding contact portion between the cage and the balls is reduced, and the friction vibration generated at this sliding contact portion is reduced,
Vibration and noise can be reduced.

Further, since the radius of curvature of the cross-sectional shape of the inner / outer ring raceway is defined to be less than 51.0 to 60.0% of the outer diameter of the ball, the contact portion between the surface of the ball and the inner / outer ring raceway surface. The elastic deformation amount of is reduced. That is, the contact ellipse of Hertz becomes smaller, the differential slip is reduced, and the bearing torque can be reduced.
The acoustic durability can be improved. On the other hand, in particular, if the radius of curvature of the cross-sectional shape of the inner / outer ring raceway is set to 60.0% or more, the maximum Hertzian contact pressure in the contact ellipse becomes excessive, and the rolling fatigue life of the inner / outer ring raceway is shortened. It is disadvantageous in terms of sound and peeling life. A preferable range of the radius of curvature of the cross-sectional shape of the inner / outer ring raceway is 51.5 to less than 58% of the outer diameter of the ball.
Further, by setting the radius of curvature of the cross section of the outer ring raceway to be equal to or greater than the radius of curvature of the cross section of the inner ring raceway,
The difference in contact surface pressure with the outer ring raceway is reduced, and vibration reduction, torque reduction, and acoustic durability are improved.

Further, in the rolling bearing of the present invention, when the outer ring and the inner ring rotate relative to each other, the friction acting between the outer ring raceway and the inner ring raceway and the raceway surface of the ball is reduced, and the heat generated inside the rolling bearing is reduced. Can be suppressed. As a result, it is possible to suppress the deterioration of the grease composition enclosed inside and improve the acoustic durability of the ball bearing.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION The ball bearing of the present invention will be described in detail below with reference to the drawings.

In the present invention, the structure of the ball bearing is not limited except for the shape of the cage described later, and the structure shown in FIG. 1, for example, can be used. As described above, in this ball bearing, the inner ring 2 having the inner ring raceway 1 on the outer peripheral surface and the outer ring 4 having the outer ring raceway 3 on the inner peripheral surface are concentrically arranged, and the space between the inner ring raceway 1 and the outer ring raceway 3 is arranged. Further, a plurality of balls 5 and 5 are rotatably provided. Further, both the inner ring raceway 1 and the outer ring raceway 3 are deep groove type, and the balls 5, 5 are rotatably held in pockets 7, 7 provided in a cage 6. Cage 6
Is a corrugated press cage, and is a pair of elements 8 formed by corrugating a metal plate material in a corrugated shape by press molding.
It is a combination of 8. Each of the elements 8, 8 has a plurality of substantially semi-cylindrical recesses 9, 9 for forming the pockets 7, 7 at a plurality of circumferential positions. Then, the pair of elements 8 and 8 are butted against each other at the portions separated from the recesses 9 and 9, and these respective portions are connected to the plurality of rivets 10.
The cage 6 has an annular shape and pockets 7, 7 at a plurality of circumferential positions.

In the present invention, the shape of the inner surface of the cage 6 is
A spherical surface formed of a spherical concave surface having a radius of curvature slightly larger than the radius of curvature of the ball 5, and having a radius of curvature larger than that of the spherical surface, and smoothing from the edge of the spherical surface toward the opening side edge of the pocket 7. And a curved surface portion continuous with.

That is, FIG. 2 shows the cage 6 along the width direction.
Although it is a cross-sectional view, the inner peripheral surface of each pocket 7 has a central portion.
Spherical portion 15 and a curved surface continuously extending from both end edges thereof
And part 18. The spherical surface portion 15 is used for each pocket.
Formed over almost the entire length of the inner peripheral surface of the gut 7, the balls 5 roll
Radius of curvature R of surface_Five Radius R slightly larger than₁₅Have
It is a spherical concave surface. Further, the curved surface portion 18 has a spherical surface portion 15.
Of the opening end of each pocket 7 continuously from both widthwise edges
And has a radius of curvature R larger than that of the spherical portion 15.
₁₈(R₁₈> R₁₅> R_Five ) Has. In addition, the curved surface portion 18,
The inner edge of 18 and the widthwise edge of the spherical portion 15 are smoothly
It is continuous. That is, the tangent line at both edges of the spherical portion 15
Direction and the tangential direction at the inner edges of the curved surface portions 18, 18.
Are formed to coincide with each other. In addition, the spherical surface part 15 and
And curved surface length 18, 18 arc length L ₁₅, L₁₈Is by design
However, it is preferable to regulate within the following range, for example:
Yes. L₁₅= R₁₅・ Θ₁₅= 2R_Five X (5 to 15%) L₁₈= R₁₈・ Θ₁₈= 2R_Five X (5 to 15%)

The shape of each of the pockets 7 as viewed from the radial direction of the cage 6 is, as shown in an exaggerated manner in FIG. 3, a shape that is slightly crushed into a rugby ball shape rather than a circular shape. That is, the depth D ₇ of each pocket 7 is smaller than the radius of curvature R ₁₅ of the spherical surface portion 15 as in the conventional structure shown in FIG. Especially in the case of the present invention, the difference between these D ₇ and the radius of curvature R ₁₅ a (R ₁₅ -D _7), is made larger than the case of the conventional structure described above. Therefore, in the case of this example,
As shown in FIG. 3, a point P ₁ where the spherical surface portion 15 forming each pocket 7 and the rolling surface of the ball 5 are in sliding contact is relatively large from the widthwise central portion of the pocket 7 toward the widthwise end portion. It exists in a displaced position. That is, the contact angle α (the center of the ball 5 and the point P
_The angle of intersection of the straight line connecting ₁ with the line representing the circumferential direction of the cage 6) is larger than in the case of the conventional structure shown in FIG. 9 described above. The contact angle α is larger than the contact angle (normally 10 to 20 °) of the ball bearing in which the cage 6 is incorporated (90 ° at maximum). Therefore, as shown in FIG. 3, a relatively large gap 19 exists between the rolling surface of each ball 5 and the inner peripheral surface of the pocket 7.

In the cage 6 constructed as described above, the inner peripheral surface of each pocket 7 and the rolling surface of the ball 5 rub against each other only on the spherical surface portion 15 and not on the curved surface portions 18 and 18. Therefore, the friction area between the inner peripheral surface of each pocket 7 and the rolling surface of the ball 5 is reduced, the frictional vibration generated at the sliding contact portion between the cage 6 and the ball 5 is reduced, and the vibration and noise are reduced. To do. In addition, the pair of curved surface portions 1 formed so as to sandwich the spherical surface portion 15 therebetween.
Between the balls 8 and 18 and the rolling surface of the ball 5, there are wedge-shaped gaps 17a and 17a, as shown in FIG. Therefore, during operation of the ball bearing, the lubricant adhering to the rolling surface of the ball 5 is smoothly taken in from the wedge-shaped clearances 17a, 17a to the clearance existing between the spherical surface portion 15 and the rolling contact surface. Moreover, the curved surface portions 18, 18 are provided on the inner diameter side, the outer diameter side of each pocket 7, and over the entire length of both openings, and the wedge-shaped spaces 17a, 17a are also provided over the entire length of both opening portions. The lubricant is effectively taken into the gap existing between the spherical surface portion 15 and the rolling surface of the ball 5. As a result, the friction acting on the sliding contact portion between the cage 6 and the balls 5 is further reduced, the frictional vibration generated at this sliding contact portion is reduced, and the vibration and noise are reduced.

Moreover, as shown in FIG. 3, a relatively large gap 19 is provided between the rolling surface of the ball 5 and the inner peripheral surface of the pocket 7.
Exists. Of the rolling surfaces of the balls 5, the lubricant particularly adhering to the rolling surfaces passes through the gaps 19 and is scarcely scraped off, and the rolling surfaces and the inner ring raceway 1 and the outer ring raceway 3 (FIG. 1). It is sent to the contact part with. Therefore, a sufficient amount of lubricant is sent to the abutting portion to improve the lubricity of the ball bearing and improve the durability of the ball bearing.

As shown in FIG. 4, the cage 6 has a pair of curved surface portions 18, 18 provided on both sides of the spherical surface portion 15 so that the inner peripheral surface of the pocket 7 is formed in a linear shape. You can also do it. That is, each of these curved surface portions 18, 18 is a conical concave surface, and the radius of curvature of the cross-sectional shape is infinite (∞). Other configurations and operations are similar to those of the above-described example.

In the ball bearing of the present invention, the radius of curvature of the cross-sectional shape of the inner ring raceway 1 and the radius of curvature of the cross-sectional shape of the outer ring raceway 3 are defined to be less than 51.0 to 60.0% of the outer diameter of the ball 5. Has been done. As a result, the amount of elastic deformation at the contact portion between the inner ring raceway 1 and the outer ring raceway 3 and the surface of the ball 5 is reduced,
Hertz's contact ellipse becomes smaller and differential slip is reduced,
The bearing torque can be reduced and the acoustic durability can be improved. On the other hand, when the radius of curvature of the cross-sectional shapes of the inner ring raceway 1 and the outer ring raceway is 60.0% or more, the maximum Hertzian contact pressure in the contact ellipse becomes excessive, and the rolling fatigue life of the inner ring raceway 1 and the outer ring raceway 3 becomes large. Deteriorates, which is disadvantageous in terms of sound and peeling life. A particularly preferable range of the curvature radii of the cross-sectional shapes of the inner ring raceway 1 and the outer ring raceway 3 is 5 of the outer diameter of the ball 5.
It is less than 1.5 to 58%.

Further, by setting the radius of curvature of the cross-sectional shape of the outer ring raceway 3 to be equal to or larger than the radius of curvature of the cross-sectional shape of the inner ring raceway 1, the difference in contact surface pressure between the inner ring raceway 1 and the outer ring raceway 3 and the surface of the ball 5 is made. It becomes smaller, and it is superior in vibration reduction, low torque, and acoustic durability.

Further, the above ball bearing is filled with grease so that the relative rotation between the inner ring 2 and the outer ring 4 is smoothly performed, and vibration and noise are not generated. Therefore, although not shown, sealing plates such as annular seal plates and shield plates are attached to the inner peripheral surfaces of both ends of the outer ring 4 to prevent grease from leaking and foreign matter from entering from the outside. Further, it is preferable to apply a thin layer of lubricating oil to the surfaces of the inner ring 2, the outer ring 4, the balls 5, and the cage 6 for the purpose of preventing rust and extending the life of the metal parts.

The grease to be filled is not particularly limited, but when low noise characteristics, that is, acoustic durability is required, as the base oil, a polar group-containing lubricating oil or a polar group-containing lubricating oil and non-polar It is preferable to use a mixed oil with a lubricating oil.

The polar group-containing lubricating oil is preferably a lubricating oil having an ester structure or an ether structure. The lubricating oil having an ester structure is not particularly limited, but it is a diester oil obtained from the reaction of a dibasic acid with a branched alcohol, a carbonate ester oil, an aromatic obtained from the reaction of an aromatic tribasic acid with a branched alcohol. Suitable examples thereof include group ester oils and polyol ester oils obtained by the reaction of monobasic acids and polyhydric alcohols. These may be used alone or in combination of two or more. Preferred specific examples are shown below.

As diester oil, dioctyl adipate (DOA), diisobutyl adipate (DIB
A), dibutyl adipate (DBA), dioctyl adipate (DOZ), dibutyl sebacate (DBS), dioctyl sebacate (DOS), methyl acetyl ricinoleate (MAR-N) and the like.

As the aromatic ester oil, trioctyl trimellitate (TOTM), tridecyl trimellitate (TDTM), tetraoctyl pyromellitate (TOTM).
PM) and the like.

Examples of the polyol ester oil include those obtained by appropriately reacting the following polyhydric alcohol with a monobasic acid. The monobasic acid reacted with the polyhydric alcohol may be used alone or in combination of two or more kinds. Furthermore,
It may be used as a complex ester which is an oligoester of a polyhydric alcohol and a mixed acid of a dibasic acid and a monobasic acid. Examples of the polyhydric alcohol include trimethylolpropane (TMP), pentaerythritol (PE), dipentaerythritol (DPE), neopentyl glycol (NPG), 2-methyl-2-propyl-1,3-propanediol (MPPD). And so on. One The base acids, mainly univalent fatty acid C ₄ -C ₁₆ are used,
Specifically, butyric acid, valeric acid, caproic acid, caprylic acid, enanthic acid, pelargonic acid, capric acid, undecanoic acid,
Lauric acid, mysteric acid, palmitic acid, tallow fatty acid, threaric acid, caproleic acid, palmitoleic acid, petroselinic acid, oleic acid, elaidic acid, asclepic acid, vaccenic acid, sorbic acid, linoleic acid, linolenic acid, sabinic acid, ricinoleic acid Etc.

Examples of the carbonate ester oil include linear or branched alkyl groups C _{6 to} C ₃₀ .

Further, as the lubricating oil having an ether structure, for example, (di) alkyldiphenyl ether oil,
(Di) alkyl polyphenyl ether oil, polyalkylene glycol oil, etc. can be mentioned.

Each of the above polar group-containing lubricating oils may be used alone or in combination. Considering torque characteristics and acoustic durability, polyol ester oil and aromatic ester oil are preferable.

On the other hand, as the nonpolar lubricating oil, mineral oil, synthetic hydrocarbon oil, or mixed oil thereof can be used. Examples of mineral oils include paraffinic mineral oils and naphthenic mineral oils. Further, examples of the synthetic hydrocarbon oil include poly-α-olefin oil and the like. Of these, synthetic hydrocarbon oils are preferable in consideration of acoustic durability.

When a mixed oil of a polar group-containing lubricating oil and a nonpolar lubricating oil is used, the polar group-containing lubricating oil is 5 to 70% of the total amount of the base oil.
It is preferable to mix such that it accounts for 10% by mass, particularly 10 to 70% by mass. In particular, the blending amount of polar group-containing lubricating oil is 5
If it is less than mass%, sufficient effects for acoustic durability and torque reduction cannot be obtained. Further, the kinematic viscosity of the base oil may be in the range of 10 to 500 mm ² / s (40 ° C.) similar to the conventional one,
The same applies to mixed oils.

When acoustic durability is not particularly required, fluorine-based lubricating oil or silicon-based lubricating oil can be used as the base oil.

The thickener is not particularly limited, and both metallic soap type and non-metal soap type thickeners can be used.

As the metal soap thickener, a monovalent and
And / or divalent organic fatty acid or organic hydroxy fat
Organic fatty acid obtained by reacting acid with metal hydroxide
Metal salts or organic hydroxy fatty acid metal salts are preferred.
The organic fatty acid is not particularly limited, but lauric acid
(C₁₂), Mistyric acid (C₁₄), Palmitic acid
(C ₁₆), Marganic acid (C₁₇),stearic acid
(C₁₈), Arachidic acid (C₂₀), Behenic acid (C_{twenty two}),
Lignoceric acid (C_{twenty four}), Beef tallow fatty acid and the like.
Further, as the organic hydroxy fatty acid, 9-hydroxy
Stearic acid, 10-hydroxystearic acid, 12-
Hydroxystearic acid, 9,10-dihydroxystea
Examples include allic acid, ricinoleic acid, and ricinoelaidic acid.
To be On the other hand, as the metal hydroxide, aluminum,
Hydroxides such as barium, calcium, lithium and sodium
Compound.

The combination of the above-mentioned organic fatty acid or organic hydroxy fatty acid and the metal hydroxide is not particularly limited, but stearic acid, tallow fatty acid or hydroxystearic acid (particularly 12-hydroxystearic acid) and hydroxylation are used. A combination with lithium is preferable because of excellent bearing performance. In addition, a plurality of types can be used in combination, if necessary.

As the non-metal soap type thickener, a urea type thickener, a fluorine type thickener and the like can be used.

The compounding amount of these thickeners may be 5 to 20% by mass, which is the same as the conventional grease.

In addition to the above-mentioned base oil and thickener, it is preferable to add a carboxylic acid or a carboxylic acid salt to the grease. By adding a carboxylic acid or a carboxylic acid salt, an adsorption film is formed, surface friction characteristics are improved, and bearing torque reduction is made more effective.
Then, the acoustic durability is improved. Examples of the carboxylic acid include oleic acid, naphthenic acid and succinic acid. The succinic acid compound is preferably alkenyl succinic acid, and examples of the succinic acid derivative include alkyl succinic acid ester, alkyl succinic acid ether, alkenyl succinic acid ester and alkenyl succinic acid ether. Further, it is appropriate that the added amount is 10% by mass or less of the total amount of grease as a whole.

Further, the grease may contain an antioxidant, a rust preventive, a metal deactivator, an oiliness agent, an extreme pressure agent, an antiwear agent, a viscosity index improver, etc., individually or insofar as the desirable characteristics are not impaired. Two or more kinds can be combined and added. All of these may be known ones. For example, as the antioxidant, amine-based, phenol-based, sulfur-based, zinc dithiophosphate, etc. can be used. As the rust preventive, petroleum sulfonate, dinonylnaphthalene sulfonate, sorbitan ester and the like can be used. Benzotriazole, sodium zincate or the like can be used as the metal deactivator. Fatty acids, vegetable oils and the like can be used as the oiliness agent. As the viscosity index improver, polymethacrylate, polyisobutylene, polystyrene or the like can be used.
These additives may be added alone or in combination of two or more, and the addition amount thereof is preferably 20% by mass or less of the total amount of grease as a whole.

[0052]

EXAMPLES The present invention will be further described based on Examples and Comparative Examples. The present invention is not limited to the examples below.

(Examples 1 to 12, Comparative Examples 1 to 9) Table 1,
Tables 2 and 3 show the grease compositions and properties of Examples 1-12 and Comparative Examples 1-9. The total amount of the thickener and the base oil was 950 g, and 50 g of additives (carboxylic acid, antioxidant, rust preventive, metal deactivator, etc.) were added to make the total amount 1
As a grease composition of 000 g. The kinematic viscosity (40 ° C) of the base oil is also shown in the table.

Then, each grease composition was filled in a test bearing and subjected to (1) bearing dynamic torque test, (2) bearing cage sound measurement, and (3) bearing acoustic durability test. In addition, Example 1
12 to 12 and Comparative Examples 2, 5 and 8 use the corrugated press cage having the spherical surface portion and the curved surface portion shown in FIG. 2 (in the table, "invention product" is added to the cage shape column). Comparative Examples 1, 3
For Nos. 4, 6, 7 and 9, the conventional corrugated press cage shown in FIG. 7 (in the table, the column of the cage shape was added as "conventional product") was used. Also, the radii of curvature of each cross-sectional shape of the inner ring raceway and the outer ring raceway are added to the table.

(1) Bearing Dynamic Torque Test The bearing dynamic torque was measured using the measuring device 30 shown in FIG. In this measuring device 30, a set of two test bearings 31 is mounted on a shaft 33 connected to an air spindle 32 using a preloading wave washer 34. Also, the test bearing 31 is placed horizontally with the drive spindle 32, and the load converter 36 is hung via the thread 35.
The output of the load converter 36 is recorded by the XY recorder 37.

The test was carried out by using the above corrugated press cage as the test bearing 31 and having an inner diameter of 15 mm and an outer diameter of 35 m.
A ball bearing with a non-contact rubber seal having a width of m and a width of 11 mm was used, 0.7 g of each grease composition of Examples 1 to 12 and Comparative Examples 1 to 9 was enclosed therein, and an axial load was 39.2 N.
The inner ring was rotated at 400 min ⁻¹ and the dynamic torque was measured.
The temperature at the time of measurement was room temperature. The measurement results are shown in Tables 1 and 2 above.
Indicated as dynamic torque. In Table 1, Table 2 and Table 3, a cross indicates a test when the dynamic torque of the ball bearing in which the grease composition conventionally used for air conditioner fan motors is enclosed is 100% (reference value). The dynamic torque of the bearing 31 is 80% or more, the Δ mark is 60% or more of the reference value and less than 80%, the ○ mark is 40% or more of the reference value and less than 60%, and the ◎ mark is Each of the values is less than 40% of the reference value. In the bearing dynamic torque test, the mark “◯”, that is, the case of less than 60% of the reference value was passed. From Tables 1 to 3, although Example 6 is the boundary level between passing and failing, all other Examples and Comparative Example 1
It can be seen that good torque characteristics can be obtained at ~ 3 and 7-9.

(2) Bearing cage sound measurement test was carried out by using a ball bearing with a non-contact rubber seal having an inner diameter of 15 mm, an outer diameter of 35 mm and a width of 11 mm equipped with each of the above corrugated press cages as the test bearing 31. Examples 1 to 1
2, 0.7 g of each grease composition of Comparative Examples 1 to 9 was enclosed, and the axial load was set to 39.2 N, and 1800 min ^−1.
Rotate the inner ring at 0 ° C and +20 using a frequency analyzer
The cage sound at C was measured. The measurement results are shown in Table 1 and Table 2.
And shown as a cage sound in Table 3. In Tables 1 and 2, ◯ indicates that the cage sound was not generated, Δ indicates that the cage sound was slightly present, and X indicates that the cage sound was large. From Tables 1 to 3, in Examples 3, 6 and 12, although a very slight cage noise was generated in the test at 0 ° C., in all other Examples and Comparative Examples 1 to 3, the cages were You can see that no sound is generated.

(3) Bearing acoustic endurance test A bearing acoustic endurance test was carried out using the actual motor endurance tester shown in FIG. This motor actual machine endurance tester rotates a pair of two test bearings 21 placed in a housing 20 with a power of a DC power source 23 via a coil 22. As test bearing 21, equipped with each of the above corrugated press cages, inner diameter φ15 mm, outer diameter φ35 mm, width 11 mm
A ball bearing with a non-contact metal seal was used. 0.7 g of each grease composition of Examples 1-12 and Comparative Examples 1-9
Enclosed. Eight test bearings 21 were prepared for each grease composition and mounted on the above-mentioned motor actual machine durability tester (axial load of about 39.2 N). Then, the actual motor endurance tester is stored in a constant temperature bath adjusted to 120 ° C.
In 0min ^-1 and 5600min ^-1, it was rotating inner ring 1000 hours. After 1000 hours, the test bearing 21 was taken out, and the acoustic characteristics of the bearing were examined according to the following evaluation criteria.

The acoustic measurement of the bearing was performed using an Anderon meter, and the bearing Anderon value immediately after each grease composition was sealed and the bearing Anderon value after 1000 hours of inner ring rotation were compared to determine the acoustic characteristics. went. The judgment result
The acoustic characteristics are shown in Tables 1, 2 and 3. Table 1, Table 2
In Table 3, the symbol ○ indicates that the acoustic characteristics are not deteriorated, the symbol Δ indicates that the acoustic characteristics are slightly deteriorated, and the symbol × indicates that the acoustic characteristics are deteriorated.
Respectively. From Table 1 and Table 2, Example 3,
In 6 and 12, although the acoustic characteristics are slightly deteriorated,
It can be seen that satisfactory acoustic characteristics are obtained in each of the examples. On the other hand, the comparative examples are all inferior in acoustic characteristics.

[0060]

[Table 1]

[0061]

[Table 2]

[0062]

[Table 3]

From the above, it was confirmed that the ball bearings of the examples all show good results in working torque, cage sound and acoustic characteristics. In particular, a remarkable difference is seen in the acoustic characteristics as compared with the comparative example.

[0064]

As described above, according to the ball bearing of the present invention, the inner peripheral surface of the pocket of the cage has a specific shape, and the dimension of the radius of curvature of the cross-sectional shape of the inner and outer ring raceways and the outer diameter of the ball. By specifying the relationship, sliding friction between the inner surface of the pocket and the surface of the ball is reduced, and vibration and noise are reduced.
Moreover, the amount of elastic deformation at the contact portion between the ball surface and the inner / outer ring raceway surface is small, that is, the Hertzian contact ellipse is small, the differential slip is reduced, and the bearing torque is reduced.
The acoustic durability is improved.

[Brief description of drawings]

FIG. 1 is a partially cut perspective view showing an example of a ball bearing of the present invention.

FIG. 2 is a sectional view showing an example of a cage incorporated in the ball bearing of the present invention.

FIG. 3 is a DD cross-sectional view of FIG.

FIG. 4 is a cross-sectional view showing another example of a cage incorporated in the ball bearing of the present invention.

FIG. 5 is a schematic configuration diagram showing a measuring device used for performing a bearing torque test in Examples.

FIG. 6 is a schematic configuration diagram showing a measuring device used for performing a bearing acoustic durability test in Examples.

FIG. 7 is a partially enlarged exploded perspective view showing an example of a conventional cage.

8 is a sectional view taken along line EE in FIG.

9 is a view corresponding to the upper half of FIG.

10 is a cross-sectional view taken along the line GG in FIG.

11 is a sectional view taken along line HH in FIG. 10, showing a state where the cage is displaced toward the inner diameter side with respect to the balls.

[Explanation of symbols]

1 Inner ring track 2 inner ring 3 outer ring orbit 4 outer ring 5 balls 6 cage 7 pockets 8 elements 9 recess 15 spherical surface 18 curved surface 20 housing 21 Test bearing 22 coils 23 DC power supply 30 Torque test measuring device 31 Test bearing 32 drive spindle 33 axes 34 Wave washer for preload 35 threads 36 load converter 37 XY recorder

Continued front page    F term (reference) 3J101 AA02 AA32 AA42 AA52 AA62                       BA21 BA37 BA45 BA51 BA53                       BA54 BA55 DA09 FA01 FA31                       GA24 GA29

Claims (2)

[Claims] 1. An outer ring having an outer ring raceway on an inner peripheral surface, an inner ring having an inner ring raceway on an outer peripheral surface, a plurality of balls rotatably provided between the outer ring raceway and the inner ring raceway, and a plurality of balls. In a ball bearing having a cage that holds balls in a rollable manner and having grease sealed in the space between the outer ring raceway and the inner ring raceway, the pocket inner peripheral surface of the cage has a radius of curvature of the ball Also has a spherical surface formed of a spherical concave surface having a slightly larger radius of curvature, and has a larger radius of curvature than the spherical surface, and is smoothly continuous from the edge of the spherical surface toward the opening side edge of each pocket. And a radius of curvature of the cross section of the inner ring raceway and a radius of curvature of the cross section of the outer ring raceway are 51.0 to 60.0 of the outer diameter of the rolling element.
%, And the radius of curvature of the cross-sectional shape of the outer ring raceway is not less than the radius of curvature of the cross-sectional shape of the inner ring raceway. 2. The ball bearing according to claim 1, wherein the radius of curvature of the curved surface portion of the cage is infinite.