JP4203843B2 - Rolling bearing and bearing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is mounted on a motor having a large rotor, a rotating machine having a belt driven rotary shaft, a pulley for rotatably supporting a timing belt of an automobile engine, a belt for driving an auxiliary machine, etc. The present invention relates to a rolling bearing and a bearing device to which a load is applied.
[0002]
[Prior art]
When the rolling bearing is operated with a radial load applied, a so-called rolling element passing vibration is generated. The rolling element passing vibration is generated when the load sharing changes depending on the position of each rolling element in the load region, and the displacement amount and the displacement direction of the rotating shaft change minutely. Since rolling element passing vibration usually has a small amplitude, it is rare that it is a problem, and even if it becomes a problem, it can be dealt with by reducing the radial clearance of the rolling bearing or applying preload. It was.
[0003]
[Problems to be solved by the invention]
However, according to the studies by the present inventors, it has been found that there is a case where rolling element passing vibration becomes a problem, and it is not always possible to cope with the problem by simply reducing the radial clearance of the rolling bearing or applying a preload. Such a phenomenon will be described.
[0004]
Due to the characteristics of the processing machine, minute undulations are often formed on the raceway surfaces of the inner and outer rings of the rolling bearing. When the bearing ring is regarded as a rigid body and the contact between the bearing ring and the rolling element is regarded as a linear spring, a predetermined vibration is generated due to the waviness of the raceway surface. The vibration caused by such swell can be reduced by the technique disclosed in Japanese Patent No. 3047764, for example.
[0005]
However, according to the study by the present inventors, it has been found that the rolling element passing vibration is amplified by the waviness of the raceway surface. FIG. 1 is a diagram illustrating a relationship between a race and a rolling element according to the presence or absence of undulation, and FIG. 2 is a diagram illustrating a load state of the rolling element. In FIG. 1, if there is no waviness on the raceway surface, a uniform gap is generated between the rolling element 1 and the raceway surface of the outer ring 2 as shown by the dotted line, but there is a waviness that minimizes the inner diameter at the lowest point. If there is, it is assumed that the rolling element 1 is pressed to the inner ring 3 side, and the gap between the rolling element 1 and the raceway surface of the outer ring 2 is not uniform according to the undulation as shown by the solid line. In an extreme case, even if a radial load is applied to the inner ring 3, a gap Δ of zero or more may be generated in the rolling element 1 at a position shifted by an angle θ from the lowest point (position where the inner diameter becomes maximum). It can be.
[0006]
As shown in FIG. 2, when a radial load Fr directed downward is applied to the inner ring 3, a load as indicated by a dotted line in the drawing is applied to the rolling element 1 if there is no undulation. That is, the rolling element 1 passing through the lower side of the horizon is gradually loaded as it moves away from the horizon, and the maximum load is applied at the lowest point (also referred to as the rolling element maximum load position). It has come to decrease. In this case, the load region is a range below the horizontal line, and the no-load region is a range above the horizontal line. On the other hand, when there is a swell as shown in FIG. 1, for example, the rolling element 1 is unloaded up to a position deviated by an angle θ from the lowest point, and the load rapidly increases from that point to the lowest point. It will be. For this reason, the rolling element passing vibration is amplified, and in some cases, there is a risk of causing problems such as separation of the raceway surface. In this case, the load region is a narrow range with an angle 2θ across the lowest point, and the no-load region is a range other than that.
[0007]
In addition, even if the undulation is not as shown in FIG. 1, if the load of the rolling element 1 does not gradually decrease or increase gradually as shown by the dotted line in FIG. Will be repeatedly received. That is, since the rolling bearing is actually elastically deformed, in consideration of this, as shown in FIG. 3 which exaggerates the deformation, there are places where the contact portion between the raceway surface and the rolling element is large and small. Specifically, a ₂ > a ₁ , a ₃ (a ₂ : radius at the time of elastic contact of Hertz in the rolling element at the lowest point, a ₁ , a ₃ : rolling element at a position shifted from the lowest point by an angle θ Radius at the time of elastic contact of Hertz), δ ₂ > δ ₁ , δ ₃ (δ ₂ : elastic deformation of Hertz in the rolling element at the lowest point, δ ₁ , δ ₃ : shifted from the lowest point by an angle θ The larger the waviness is, the larger the rolling element load is, and the smaller the rolling element load is, the smaller the rolling element load is. The torque in this case is proportional to the rolling element load with which the rolling element and the raceway contact each other, and there is a risk of causing torque fluctuation. Further, the center position in the radial direction of the rolling element is lower than the center position when the undulation is 0 by about Δ ₁ and Δ _{3 on the} outer side of the rolling element at a position shifted by an angle θ from the lowest point. the rolling elements of the point moved inward by delta _2. That is, it rotates while moving in the radial direction by this amount.
[0008]
As described above, when the load of the rolling element 1 changes, the life decreases due to the increase of the maximum rolling element load, the torque fluctuation due to the fluctuation of the rolling element load occurs during one revolution, and further, while the rolling element makes one revolution. If the center moves away from or approaches the center of the rolling bearing, vibration or noise may be generated.
[0009]
The present invention has been made in view of such problems, and provides a rolling bearing and a bearing device that can suppress the generation of vibration and noise of a rolling element due to a sudden rise in load and can achieve a long life. For the purpose.
[0010]
[Means for Solving the Problems]
A rolling bearing device according to a first aspect of the present invention is a rolling bearing on which a radial load is applied to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine . a first bearing ring having a raceway of the second race with a second raceway, and rolling elements disposed et been rollably between the first track and the second track In a rolling bearing having a minute undulation on each of the raceways,
The number of rolling elements (Z) is 6,
With respect to the raceway of at least one of the first raceway and the second raceway, the single amplitude of the swell of 3 peaks per circumference of the track is 4 or more per circumference of the track , It is characterized by being smaller than the maximum value of the half amplitude of the swell of 9 or less peaks .
A rolling bearing device according to a second aspect of the present invention is a rolling bearing on which a radial load is applied to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine. A first race ring having a second raceway, a second race ring having a second raceway, a rolling element provided to be freely rollable between the first raceway and the second raceway, In a rolling bearing having a minute undulation on each of the raceways,
The number of rolling elements (Z) is 8,
With respect to the raceway of at least one of the first raceway or the second raceway, the single amplitude of the undulation of 4 peaks per circumference of the track is 5 or more per circumference of the track, It is smaller than the maximum value of the half amplitude of the swell of 12 or less.
A rolling bearing device according to a third aspect of the present invention is a rolling bearing on which a radial load is applied in order to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine . a first bearing ring having a raceway of the second race with a second raceway, and rolling elements disposed et been rollably between the first track and the second track In a rolling bearing having a minute undulation on each of the raceways,
The number of rolling elements (Z) is 7,
With respect to the raceway of at least one of the first raceway or the second raceway, the single amplitude of the undulations of the three peaks and the four peaks per circle of the track is 5 per circle of the track. It is characterized in that it is smaller than the maximum value of the half amplitude of the swell of 9 to 9 peaks .
A rolling bearing device according to a fourth aspect of the present invention is a rolling bearing on which a radial load is applied to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine. A first race ring having a second raceway, a second race ring having a second raceway, a rolling element provided to be freely rollable between the first raceway and the second raceway, In a rolling bearing having a minute undulation on each of the raceways,
The number of rolling elements (Z) is 9,
With respect to the raceway of at least one of the first raceway or the second raceway, the amplitudes of the undulations of the four peaks and the five peaks per circle of the track are 6 per circle of the track. It is characterized in that it is smaller than the maximum value of the half amplitude of the swell of 12 or more peaks.
[0012]
[Action]
As a result of further earnest studies, the inventors have found that the rolling element passing vibration is amplified due to the waviness due to the shape error caused by the waviness, and the relationship between the number of rolling elements and the raceway surfaces of the inner and outer rings and the rolling elements. It was found that the main factor is that the gaps between and change periodically. That is, it has been found that vibration can be suppressed by adjusting the number of rolling elements and the number of undulation peaks. More specifically, according to further research by the present inventors, in a rolling bearing having an even number (Z) of rolling elements, when at least one raceway ring is a positive integer n is at least 1. , The half amplitude of the undulation having the number of peaks (Z (2n-1) / 2) per circumference of the orbit is ((Z (2n-1) / 2) +1) per circumference of the orbit As described above, it has been found that vibration can be effectively suppressed by making it smaller than the maximum value of the half amplitude of the undulation having the number of peaks of (Z (2n + 1) / 2) or less.
[0013]
Further, with respect to at least one of the first ring and the second ring in the rolling bearing, when at least the integer n is 1, per track circumference (Z (2n− 1) The amplitude of the undulation having the number of peaks of 2 ± 1) is equal to or greater than (Z (2n−3) / 2) per circle of the trajectory (provided that it is equal to or greater than 2 when n = 1). It has been found that vibration can be more effectively suppressed by making it smaller than the maximum value of the half amplitude of the waviness having a number of peaks of (Z (2n-1) / 2) or less. Although the contribution is lower than the undulation of the number of peaks per circle (Z (2n-1) / 2) of the trajectory, the peaks per circle (Z (2n-1) / 2 ± 1) of the trajectory This is because the number of waves also contributes to vibration.
[0014]
On the other hand, in the case of a rolling bearing provided with an odd number (Z) of rolling elements, at least one of the first ring and the second ring is n, which is a positive integer. 1, the half amplitude of the swell having the number of peaks of ((Z (2n-1) -1) / 2) per circumference of the orbit, and ((Z (2n-1) +1) / 2) Any one of the swell amplitudes having the number of peaks is ((Z (2n-1) +1) / 2 + 1) or more per circumference of the orbit, ((Z (2n + 1) -1) / 2). -1) It has been found that vibration can be effectively suppressed by making it smaller than the maximum value of the half amplitude of the waviness having the following number of peaks. When the number of rolling elements is an odd number, the number of peaks defined in the first invention does not become an integer, but in that case, it is considered that the number of undulations close to the specified number of peaks contributes to vibration. Therefore, we decided to handle it as described above.
[0015]
Furthermore, the number of undulation peaks is preferably 20 or less per circumference of the track.
[0016]
In addition, it is preferable that at least one of the first raceway ring and the second raceway ring is attached to a housing that houses the rolling bearing or a shaft that supports the rolling bearing with an interference fit.
[0017]
Further, at least one of the first raceway ring or the second raceway ring is a steel for bearing or carbon steel having a linear expansion coefficient of 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.). Alternatively, it is preferably formed from structural steel, and the housing or the shaft is formed from bearing steel having a linear expansion coefficient of 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.).
[0018]
If the temperature rises during the operation of the rolling bearing and the linear expansion coefficients of the bearing and the shaft or the bearing and the housing are different, the fitting stress changes. For this reason, even if the influence of the shape error is kept small in the assembled state, the shape error may change due to the temperature rise, but at least one of the first track ring or the second track ring has a linear expansion coefficient. 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.) bearing steel, and the housing or the shaft has a linear expansion coefficient of 10.1 × 10 ^{−6 to} 13.5 × 10 ^{If it is made of -6} (m / ° C) bearing steel, the linear expansion coefficient of the bearing ring and shaft of the rolling bearing or the bearing ring and housing of the rolling bearing is the same. This is desirable because it is maintained as it is. However, usually, the shaft and the housing are often made of a material different from that of the bearing race. However, in this case, it is desirable to use a material that is as close to the race as possible.
[0019]
Specifically, as a material having a linear expansion coefficient of 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.), the linear expansion coefficient is 10.1 × 10 ⁻⁶ (m / ° C.). ) Martensitic stainless steel, 12.5 × 10 ⁻⁶ (m / ° C.) bearing steel SUJ2, and 13.5 × 10 ⁻⁶ (m / ° C.) austenitic stainless steel. Also, the case-hardened steel such as SCr40 that is usually used can be applied if it is in the range of this linear expansion coefficient. The amount of elastic deformation at the maximum rolling element load position when a deep groove ball bearing having an identification number 6206 (inner diameter: 30 mm, outer diameter: 62 mm, width: 16 mm) is loaded with 5000 N which is about 25% of the dynamic load rating (see FIG. 3). Δ ₂ ) is about 36 μm. On the other hand, if the temperature difference between the outer ring and the housing due to temperature rise is 10 ° C., the dimensional change in the range of linear expansion coefficient 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.) is ( 13.5-10.1) × 10 ⁻⁶ × 0.062 × 10≈2.1 × 10 ⁻⁶ (2.1 μm), which is a sufficiently small value compared to the amount of elastic deformation. The change is not expected to be affected. As the material for the housing and the shaft, the bearing steel, structural steel such as S20C, and other carbon steel can be used.
[0020]
Further, in the rolling bearing, the first race ring is an inner ring, the second race ring is an outer ring, and the inner ring rotates, and the linear expansion coefficient of each race ring is: It is preferable that it is below the linear expansion coefficient of the housing. In such a case, the inner ring rotates and the inner ring and the shaft are interference-fitted, and the other outer ring and the housing are subject to a temperature rise. The combination is such that at least the tightening margin is tight and does not affect the shape change of the outer ring.
[0021]
In the rolling bearing, the first race is an inner race, the second race is an outer race, and the outer race is rotated. The linear expansion coefficient of each race is It is preferable that it is equal to or greater than the linear expansion coefficient of the shaft. In such a case, the outer ring rotates and the outer ring and the housing are interference-fitted, and the temperature of the other inner ring and the shaft increases due to the temperature rise. The combination is such that at least the tightening margin does not affect the shape change of the inner ring.
[0022]
Furthermore, in the rolling bearing in which a load is applied mainly in the radial direction, it is preferable that a load region in which the load is applied to the rolling element and a non-load region in which the load is not applied to the rolling element are present. In particular, the present invention is effective when the number of rolling elements is small with respect to the dynamic load rating of the bearing. That is, when the rolling element has a small diameter, a rolling bearing having a large number of rolling elements and a rolling bearing having a large number of rolling elements and a small number of rolling elements having the same dynamic load rating, the present invention is effective by the latter. is there.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 4 is a sectional view of the rolling bearing according to the embodiment of the present invention.
[0024]
In an example shown in FIG. 4A, an idler pulley 5 used in an automobile engine or the like has a plurality of rolling wheels arranged in its center hole 5a so as to be freely rollable between an outer ring 2, an inner ring 3, and both wheels 2 and 3. A rolling bearing 4 having a moving body 1 is fitted. Further, the inner ring 3 of the rolling bearing 4 is fitted to the fixed shaft 6. The idler pulley 5 hangs an endless belt (not shown) on the outer peripheral surface 5b to give tension, and rotationally drives the rotating shaft and camshaft of the auxiliary machine. The rolling bearing 4 is an example of inner ring fixing and outer ring rotation mainly receiving a radial load. The linear expansion coefficients of the two wheels 2 and 3 of the rolling bearing 4 are preferably 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.), and the linear expansion coefficients of the idler pulley 5 and the fixed shaft 6 are Although it is preferable that it is 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.), it is desirable that at least the linear expansion coefficients of the two wheels 2 and 3 are not less than the linear expansion coefficient of the fixed shaft 6.
[0025]
In another example shown in FIG. 4B, both ends of a rotating shaft 6 ′ having a rotor 6a ′ attached to the center of the housing 5 ′ are rotatably supported by a pair of rolling bearings 4 ′. The rolling bearing 4 ′ includes an outer ring 2 ′, an inner ring 3 ′, and a plurality of rolling elements 1 ′ disposed so as to be freely rollable between both the wheels 2 ′ and 3 ′. Such a rolling bearing 4 ′ is an example of inner ring rotation and outer ring fixation mainly receiving a radial load. The linear expansion coefficients of both wheels 2 'and 3' of the rolling bearing 4 'are preferably 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.), and the housing 5 ′ and the rotating shaft 6 ′ The linear expansion coefficient is preferably 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.), but at least the linear expansion coefficients of both wheels 2 ′ and 3 ′ are less than or equal to the linear expansion coefficient of the housing 5 ′. It is desirable to be.
[0026]
Next, as shown in FIGS. 1 and 2, let us consider a case where a certain rolling element comes to the center of the load region. At that time, in both adjacent rolling elements, the number of undulation peaks with the largest gap with the raceway surface is Z (2n-1) / 2. Here, Z is the number of rolling elements that circulate, and n is a natural number. For example, when the number of rolling elements is six, the number of undulation peaks at which the gap between the rolling elements and the raceway surface is the largest is three. , 9 mountains, 15 mountains, and so on.
[0027]
If this number of undulations is large, the rolling element is likely to be in a state where no load is applied even at a position in the load region, and an abrupt load may be applied to the rolling element.
[0028]
The number of undulation peaks Z (2n-1) / 2 described above does not exist when the number of rolling elements Z is an odd number. In this case, it is considered that the number of undulations close to the value of the number Z of rolling elements affects the rolling elements. That is, it is considered that the undulation of the number of peaks represented by (Z (2n-1) -1) / 2 and (Z (2n-1) +1) / 2 is affected.
[0029]
More specifically, the relationship between the number of undulation peaks and their half amplitude will be described with reference to FIG. FIG. 5 is a diagram showing an example of a curve showing a general relationship between the number of undulations of the track surface and the half amplitude. In the present embodiment, when using even (Z) rolling elements, the single amplitude of (Z (2n-1) / 2) undulations per circumference of the rolling element trajectory is (Z (2n-1). ) / 2 + 1) or more and (Z (2n + 1) / 2) or less, the undulation piece amplitude of the number of peaks is made smaller than the maximum value.
[0030]
As shown by the curve C in FIG. 5, generally, the undulation piece amplitude tends to decrease as the number of peaks increases. If this tendency is followed, the half amplitude A of Z (2n-1) / 2 peaks per circumference of the rolling element track should be the maximum half amplitude among the more peaks. On the other hand, in the present embodiment, against the above-mentioned tendency, the half amplitude A is undulated with a number of peaks of (Z (2n-1) / 2 + 1) or more and (Z (2n + 1) / 2) or less. By controlling the swell, the vibration is effectively suppressed so that it does not become maximum within the range (in the range indicated by X) (that is, A <B (maximum half amplitude)). Such management can be achieved by measuring parts and combining them based on the measurement results.
[0031]
Next, with reference to FIG. 6, the relationship between the number of undulation peaks and the half amplitude will be described for another example. FIG. 6 is a diagram showing another example of a curve showing a general relationship between the number of undulations of the track surface and the half amplitude. In the present embodiment, when using an odd number (Z) of rolling elements, ((Z (2n-1) -1) / 2) peaks and ((Z (2n-1) per one circumference of the rolling element track). ) +1) / 2) At least one of the amplitudes of the undulations of the mountain is not less than ((Z (2n-1) +1) / 2 + 1) mountain and not more than ((Z (2n + 1) -1) / 2-1) mountain. It is set to be smaller than the maximum value of the amplitude of the swell piece of a certain number of peaks.
[0032]
As shown by the curve C in FIG. 6, generally, the undulation piece amplitude tends to decrease as the number of peaks increases. If this tendency is followed, ((Z (2n-1) -1) / 2) peak amplitude A1 and ((Z (2n-1) +1) / 2) peak per circle of the rolling element trajectory The amplitude A2 should be the largest half-amplitude among the higher peaks. On the other hand, in the present embodiment, against the above tendency, the one amplitude (here, A2) is set to ((Z (2n-1) +1) / 2 + 1) mountain or more, ((Z (2n + 1) -1). ) / 2-1) By managing the undulation so that it does not become the maximum within the undulation of the number of peaks or less (within the range indicated by X) (that is, A2 <B (maximum half amplitude)). This effectively suppresses vibration.
[0033]
With reference to FIG. 7, the relationship between the number of undulation peaks and the half amplitude will be described for another example. FIG. 7 is a diagram showing still another example of a curve showing a general relationship between the number of undulations of the track surface and the half amplitude. In this embodiment, when an even number (Z) of rolling elements are used, (Z (2n−1) / 2-1) peak amplitudes A3 and (Z (2n−) per circle of the rolling element trajectory. 1) / 2 + 1) The peak amplitude A4 of the peak of the swell is not less than ((Z (2n-3) / 2) peak and not more than (Z (2n-1) / 2-1) peak. It is made to become smaller than the maximum value of.
[0034]
As shown by the curve C in FIG. 7, generally, the undulation piece amplitude tends to decrease as the number of peaks increases. In the example shown in FIGS. 5 and 6, the half amplitude of the undulation was determined so as to counter this tendency. On the other hand, the present inventors have found that the vibration suppression effect can be further enhanced by following this tendency. I found it. More specifically, the half amplitudes A3 and A4 are within the undulation of the number of peaks of Z (2n-3) / 2 or more and less than Z (2n-1) / 2-1 (in the range indicated by X). Therefore, such an effect is achieved by managing the swell so that it does not become the maximum (that is, A3, A3 <B (maximum half amplitude)).
[0035]
When the number of rolling elements is large (for example, 10), as shown in FIG. 8, the rolling elements (1) in the radial load direction support the load, and the rolling elements (2) and (10) on both sides share the load. If not, the distance between the rolling elements (3) and (9) on both sides and the raceway surface will be narrowed, so collision between the rolling element and the raceway surface will not occur easily, and vibration and noise will not easily occur. Become. Therefore, when the number of rolling elements is 10 or more, the above-described strict management is not necessary, and when using an even number (Z) of rolling elements as shown in FIG. (Z (2n-1) / 2-1) peak amplitude A3 and (Z (2n-1) / 2 + 1) peak undulation amplitude A4 are equal to or greater than ((Z (2n-3) / 2) peaks , (Z (2n-1) / 2-1) It is sufficient to make it smaller than the maximum value of the undulation piece amplitude of the number of ridges equal to or less than the hill. For this purpose, it is better to close the radial clearance of the rolling bearing.
[0036]
Furthermore, since undulations of 20 or more ridges rarely become a problem, swells of 20 or less ridges may be considered. For example, if Z = 6, the number of undulations in question is 3, 9, and 15, and the amplitude of the undulations of the 3 ridges is the amplitude among the undulations of 4 or more and 9 or less. If the amplitude of the nine peaks is not the maximum among the peaks of 10 to 15 peaks, and the same is true for the 15 peaks, the above problem will be solved. A remarkable effect can be expected.
[0037]
Further, since the amplitude of the undulation usually decreases as the number of peaks increases, the most problematic mountain number n is 1, and it is effective to take measures when n = 1.
[0038]
Further, as a method for managing the swell size, it is conceivable to make the swell size smaller than the maximum value among all swell sizes. The size range is considered to be effective if it is about half the maximum value.
[0039]
Further, if the amplitude of the swell is controlled and the clearance inside the bearing is further reduced, a further effect can be expected.
[0040]
As described above, the present invention has been described by the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made within the scope of the technical idea of the present invention. For example, the rolling bearing may be incorporated in the bearing device.
[0041]
【The invention's effect】
According to the rolling bearing of the present invention, by suppressing the shape error (swell) of the inner ring raceway surface and the outer ring raceway surface, the load applied to the rolling element in the load region becomes smooth, and the generation of vibration and noise is suppressed. Further, it is possible to suppress the life reduction of the rolling element due to a sudden load.
[Brief description of the drawings]
FIG. 1 is a diagram showing a relationship between a race and rolling elements depending on the presence or absence of undulations.
FIG. 2 is a diagram showing a load state of a rolling element.
FIG. 3 is a diagram showing the relationship between the waviness of the raceway surface and the deformation of the rolling element that receives a radial load.
FIG. 4 is a sectional view of a rolling bearing incorporated in an idler pulley.
FIG. 5 is a diagram showing a general relationship between the number of undulations of a track surface and a half amplitude.
FIG. 6 is a diagram showing a general relationship between the number of undulations of a track surface and a half amplitude.
FIG. 7 is a diagram showing a general relationship between the number of undulations of a track surface and a half amplitude.
FIG. 8 is a view showing an example in which a radial load is applied to the outer ring from above on the rolling bearing.
[Explanation of symbols]
1, 1 'ball (rolling element)
2, 2 'outer ring 3, 3' inner ring 4, 4 'rolling bearing 5 idler pulley 5' housing 6 fixed shaft 6 'rotating shaft

Claims (11)

A rolling bearing to which a radial load is applied to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine, the first bearing ring having a first track; comprises a second bearing ring having a second raceway, and a rollably formed et the rolling elements between the first track and the second track, minute waviness on each track In rolling bearings with
The number of rolling elements (Z) is 6,
With respect to the raceway of at least one of the first raceway and the second raceway, the single amplitude of the swell of 3 peaks per circumference of the track is 4 or more per circumference of the track , A rolling bearing characterized by being smaller than the maximum value of the single amplitude of the waviness of 9 or less peaks .   A rolling bearing to which a radial load is applied to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine, the first bearing ring having a first track; A second race ring having a second raceway, and a rolling element provided between the first raceway and the second raceway so as to be freely rollable. In existing rolling bearings,
  The number of rolling elements (Z) is 8,
  With respect to the raceway of at least one of the first raceway or the second raceway, the single amplitude of the undulation of 4 peaks per circumference of the track is 5 or more per circumference of the track, A rolling bearing characterized by being smaller than the maximum value of the single amplitude of the swell of 12 or less. A rolling bearing to which a radial load is applied to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine, the first bearing ring having a first track; comprises a second bearing ring having a second raceway, and a rollably formed et the rolling elements between the first track and the second track, minute waviness on each track In rolling bearings with
The number of rolling elements (Z) is 7,
With respect to the raceway of at least one of the first raceway or the second raceway, the single amplitude of the undulations of the three peaks and the four peaks per circle of the track is 5 per circle of the track. A rolling bearing characterized by being smaller than the maximum value of the single amplitude of the swell of 9 to 9 peaks .   A rolling bearing to which a radial load is applied to rotatably support a pulley engaged with a timing belt of an automobile engine or a belt for an auxiliary machine, the first bearing ring having a first track; A second race ring having a second raceway, and a rolling element provided between the first raceway and the second raceway so as to be freely rollable. In existing rolling bearings,
  The number of rolling elements (Z) is 9,
  With respect to the raceway of at least one of the first raceway or the second raceway, the amplitudes of the undulations of the four peaks and the five peaks per circle of the track are 6 per circle of the track. A rolling bearing characterized by being smaller than the maximum value of the single amplitude of the swell of 12 to 12 peaks. The rolling bearing according to any one of claims 1 to 4, wherein the rolling bearing has a load area where a load is applied to the rolling element during rotation and a non-load area where the load is not applied to the rolling element. The at least one of the first raceway ring and the second raceway ring is attached to a housing that houses the rolling bearing or a shaft that supports the rolling bearing by an interference fit. The rolling bearing according to any one of 5 . At least one of the first raceway ring or the second raceway ring is made of bearing steel having a linear expansion coefficient of 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.),
The housing or the shaft is formed of bearing steel, carbon steel, or structural steel having a linear expansion coefficient of 10.1 × 10 ^{−6 to} 13.5 × 10 ⁻⁶ (m / ° C.). The rolling bearing according to any one of claims 1 to 6 . In the rolling bearing, the first race ring is an inner ring, the second race ring is an outer ring, and the inner ring is rotated. The rolling bearing according to claim 7 , which has a coefficient of linear expansion equal to or less than that. In the rolling bearing, the first bearing ring is an inner ring, the second bearing ring is an outer ring, and the outer ring rotates, and the linear expansion coefficient of each bearing ring is the shaft The rolling bearing according to claim 7 , wherein the rolling coefficient is equal to or greater than the linear expansion coefficient.   The rolling bearing according to claim 1, wherein the pulley is an idler pulley for an automobile engine. Bearing apparatus characterized by using a rolling bearing according to any one of claims 1 to 10.

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