JPH09229057A - Rolling bearing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate friction on the contact part of flange faces with the end faces of a rolling body so as to damp the vibration when bearing vibration such as radial vibration is generated by setting at least either surface roughness of the flange faces or the end faces of the rolling body contacted with the flanges in the specific range of roughness against the roughness of inner/outer ring raceway surfaces and the rolling face of the rolling body. SOLUTION: In a rolling bearing 2, at least either surface roughness of flange faces 4a or the end faces 5a of a rolling body 5 contacted with the flanges satisfy the following relation against the roughness of inner/outer ring raceway surfaces 3R, 4R and the rolling face 5b of the rolling body 5. 2(σ1 <2> +σ2 <2> )<1/2> (σ3 <2> +σ4 <2> )<1/2> 4(σ1 <2> +σ22 )<1/2> where σ1 : inner/outer ring raceway surface roughness (centerline mean roughness) σ2 : raceway surface roughness of a rolling body, σ3 : inner/outer ring flange part roughness, σ4 : rolling body end face surface roughness.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling bearing having a collar portion, and more particularly to reducing vibration of the rolling bearing.

[0002]

2. Description of the Related Art Since a rolling bearing itself has a small vibration damping capability, an elastic body is inserted in the outer diameter portion of the bearing or a viscous damper structure is provided in the housing portion in order to suppress the vibration of a system including the rolling bearing. Is generally well known.

Further, in a rolling bearing having a collar portion, from the viewpoint of preventing seizure in the collar portion, the roughness of the contact surface between the collar portion and the collar portion of the rolling element is improved as much as possible, and the contact portion Friction resistance is being reduced.

[0004]

However, in the conventional vibration suppressing method using the elastic body or providing the viscous damper structure, the effect is not sufficient, and the structure is complicated and the applicable range is limited. There are unresolved issues.

Further, if the roughness of the contact surface between the collar portion and the rolling element is improved, the problem such as seizure can be solved, but it may have an adverse effect on the reduction of vibration. It remains a solution.

Therefore, the present invention has been made by paying attention to such unsolved problems of the prior art, and in a rolling bearing having a flange portion, the roughness of the flange portion or the end surface of the rolling element in contact with the flange is provided. It is an object of the present invention to reduce the vibration level of the rolling bearing by determining that the roughness of at least one of the two has a specific relationship with the rolling surface roughness of the inner / outer rings and the rolling elements.

[0007]

According to a first aspect of the present invention, in a rolling bearing having a flange surface, at least one of the end surfaces of the rolling element in contact with the flange surface or the collar has a surface roughness of It is characterized by having the following relationship with the roughness of the inner / outer ring raceways and the rolling surfaces of the rolling elements. 2 (σ ₁ ² + σ ₂ ² ) ^1/2 <(σ ₃ ² + σ ₄ ² ) ^1/2 <4 (σ
₁ ² + σ ₂ ² ) ^1/2 where σ ₁ ; inner / outer ring raceway surface roughness (centerline average roughness) σ ₂ ; rolling element raceway surface roughness σ ₃ ; inner / outer ring flange surface roughness σ ₄ Roughness of end surface of rolling element When vibration (for example, radial vibration) occurs in a rolling bearing having a flange surface, friction is usually generated between the rolling element and the flange surface which are in contact with the flange surface. According to the present invention, since the contact portion is roughened, the damping action is enhanced and the vibration is effectively damped.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the upper half of a cylindrical roller bearing (NU type) 2 of the outer ring double-faced type mounted on a drive shaft 1 and an explanatory schematic diagram of its vibration measurement.

The inner ring 3 is fitted and fixed to the drive shaft 1.
The outer ring 4 has both brim surfaces 4a, 4a. Rolling element 5
It is a roller, and the end surfaces 5a, 5a of its head are the collar surface 4 of the outer ring
a and 4a, respectively. 6 is a cage.

With respect to this cylindrical roller bearing 2, as a sample having partially different roughness, Example 1 and Comparative Example 1 and Comparative Example 2 were prepared and subjected to a vibration test, and the results were compared. The test method is as follows.

A sample cylindrical roller bearing (model number is N
U218) was attached, and it was rotated at 1800 rpm by a motor (not shown) while being lubricated with No. 60 spindle oil at room temperature. The vibration level at that time was measured by the acceleration pickup 7 mounted on the outer diameter portion of the outer ring 4, and the vibration spectrum was recorded.

Table 1 shows the surface roughness (center line average roughness; μmRa) of each constituent part of each sample of the example and the comparative example. In Table 1, σ ₁ is each raceway surface 3R and 4R of the inner ring 3 and the outer ring 4.
, Σ ₂ is the surface roughness of the rolling surface 5b of the roller 5, σ ₃ is the surface roughness of the flange surface 4a of the outer ring 4, and σ ₄ is the surface roughness of the head end surface 5a of the roller 5. .

[0013]

[Table 1]

Each sample has inner and outer raceway surfaces 3R, 4R
And the rolling surfaces 5b of the rollers all have the same surface roughness (σ ₁ = σ ₂
= A 0.05μmRa), surface roughness of the head end surface 5a of the roller in contact therewith and the surface roughness sigma ₃ of the outer ring of the flange surface 4a sigma ₄
And changed respectively.

The degree of the surface roughness σ ₃ of the flange surface and the surface roughness σ ₄ of the head end surface of the roller (hereinafter, collectively referred to as “roller / collar contact surface roughness” σ ₃ , σ ₄ ) It was classified into the following three cases according to.

Case 1 (Example): Roller / collar contact surface roughness
Σ_Three, Σ_FourIs the surface roughness σ of each raceway surface of the inner and outer rings.₁as well as
Surface roughness σ of rolling surface of rollers_Two(Hereafter, collectively, "race surface"
Roughness "σ₁, Σ_TwoBearings that are about twice as bad as
group. Roughness is 2 (σ ₁ ^Two+ Σ_Two ^Two)^1/2Expressed by

Case 2 (Comparative Example): A bearing group in which the roller / collar contact surface roughness σ ₃ , σ ₄ is about 4 times worse than the race surface roughness σ ₁ σ ₂ . Roughness is 4 (σ ₁ ² + σ ₂ ² )
^{Expressed as 1/2} .

Case 3 (Comparative Example): A group of bearings having good roller / collar contact surface roughness σ ₃ , σ ₄ . Roughness (σ ₃
It is represented by ² + σ ₄ ² ) ^1/2 . FIG. 2 shows the measurement result of the vibration spectrum.

In case 3 of the comparative example in which the roller / rib contact surface roughnesses σ ₃ and σ ₄ are good, when vibration occurs in the drive shaft 1,
The vibration level at the outer diameter portion of the outer ring 4 is high. In particular, it becomes highest at 4 kHz, which is the frequency at which the human ear feels most uncomfortable. Compared with this, the roller / collar contact surface roughness σ ₃ , σ ₄
The vibration level is low in case 1 of the rougher embodiment.
However, in case 2 of the comparative example in which the roughnesses σ ₃ and σ ₄ of the roller / collar contact surfaces are further deteriorated, the vibration damping effect as large as that of case 1 is not seen, but rather it becomes high in the entire frequency band of 0 to 10 kHz. There is.

The reason will be examined based on FIG. The vertical axis shows the vibration level at a frequency of 4 kHz measured at the outer diameter of the outer ring, and the horizontal axis ^shows the ratio of (σ ₃ ² + σ ₄ ² ) ^1/2 to (σ ₁ ² + σ ₂ ² ) ^1/2 . Then, the values for each sample in each case were plotted. (Σ ₁ ² + σ ₂ ² ) ^1/2
Is the race surface (with the raceways of the inner and outer raceways)
It is a roughness factor that determines the oil film parameter between the two, and is a factor that indicates the lubrication state of the main rolling surface. Therefore, based on this, the roller / rib contact surface roughness (σ ₃ ² + σ ₄ ² ) ^1/2 evaluate.

As is apparent from FIG. 3, in case 3, the ratio values are all in the range of less than 2, and the vibration level thereof is as high as 10 dB to 20 dB. The reason is as follows. Vibration generated in the drive shaft 1 is transmitted to the outer ring 4 via the inner ring 3 and the rollers 5, and at this time, relative movement due to vibration occurs between the head end surface 5a of the roller 5 and the flange surface 4a of the outer ring 4. Normally, the roller 5 is in contact with the outer ring flange surface 4a, and therefore friction is generated in the contact portion due to the relative movement of the both. Therefore, by increasing this friction, that is, by roughening the roller / collar contact surface roughness σ ₃ , σ ₄ , the vibration damping effect can be enhanced and the vibration can be damped. The surface roughness is good and its extent (σ ₃
^{Because 2} + σ ₄ ² ) ^1/2 is small, there is no vibration damping effect.

On the other hand, in case 2, the ratio values are all in the range of more than 4, and the vibration level thereof is as high as 10 dB to 20 dB as in case 3. The reason for this is the degree of roughness of the roller / collar contact surface (σ ₃ ² + σ ₄ ² ) ^1/2
Is too large, for example, the brim surface 4a and the head end surface 5
seizure with a occurs, vibration (noise) of the bearing itself due to slippage between the inner ring 3 and the place becomes large, or abnormal wear between the flange surface 4a and the head end surface 5a increases, As a result, the vibration level becomes high.

On the other hand, in the case 1 of the embodiment, the value of the ratio is within the range of 2 to 4, and the vibration level thereof is as low as 10's dB or less. It is considered that the roller / collar contact surface roughness has an appropriate size, and this acts as a kind of brake on the radial vibration of the bearing and exerts a vibration suppressing effect. Here, by setting the value of the ratio within the range of 2.25 to 3.75, it is possible to suppress the vibration level to a very preferable level of about 10 dB or less.

Table 2 is shown in Table 1 based on the result of FIG.
Surface roughness of each component of the bearing (centerline average roughness) σ₁~ Σ_Four
2 times and 4 times the roughness of the race surface, that is, 2
(Σ₁ ^Two + Σ_Two ^Two)^1/2And 4 (σ₁ ^Two+ Σ_Two ^Two)^1/2And this
Roughness / Roughness of contact surface roughness (σ _Three ^Two+ Σ_Four ^Two)^1/2And each
Calculated for each case, outside the bearing outer ring at a frequency of 4 kHz
It shows the relationship between the diameter and the vibration level.

[0025]

[Table 2]

Based on the above results, in the rolling bearing of the present invention, the degree of roughness of the roller / collar contact surface (σ ₃ ² +
σ ₄ ² ) ^1/2 and race surface roughness (σ ₁ ² + σ ₂ ² ) ^1/2
It was possible to achieve a reduction in vibration by defining the relationship between and as in the following equation (1). 2 (σ ₁ ² + σ ₂ ² ) ^1/2 <(σ ₃ ² + σ ₄ ² ) ^1/2 <4 (σ ₁ ² + σ ₂ ² ) ^1/2 …… (1) In addition, the inner ring 3 and the outer ring 4 A vibration damping effect due to the influence of the surface roughness σ ₁ of each raceway surface 3R and 4R and the surface roughness σ ₂ of the rolling surface 5b of the roller 5 can be expected, but the above-mentioned roller / collar contact is experimentally observed. The surface roughness σ ₃ and σ ₄ were not as large as the effects.

Further, in the above embodiment, the inner and outer race surface roughness σ ₁ and the race of the rolling element are respectively set for both the inner and outer ring flange surface roughness σ ₃ and the roller head (end surface) roughness σ _4. Although the case where the surface roughness is about ₂ to 4 times rougher than the surface roughness σ ₂ has been described, the present invention is not limited to this, and only one of σ _{3 and} σ ₄ may be roughened.

Further, although the cylindrical roller bearing has been described in the above embodiment, the present invention can be applied to various rolling bearings having other flanges such as a tapered roller bearing.

[0029]

As described above, according to the rolling bearing of the present invention, the surface roughness of at least one of the flange surface or the end surface of the rolling element in contact with the flange is determined by the inner / outer ring raceway surface and the rolling element. Since the bearing surface is roughened within a specific range relative to the roughness of the rolling surface, when bearing vibration such as radial vibration occurs, friction is generated at the contact part between the flange surface and the end surface of the rolling element to damp the vibration. Has the effect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an upper half of a cylindrical roller bearing with a double-edged outer ring and an explanatory schematic diagram of vibration measurement thereof.

FIG. 2 is a graph showing a measurement result of a vibration spectrum in FIG.

FIG. 3 is a graph showing the relationship between the vibration level and the rib contact surface roughness.

[Explanation of symbols]

 1 Drive shaft 2 Rolling bearing 3 Inner ring 3R Raceway surface 4 Outer ring 4a Collar surface 4R Raceway surface 5 Rolling element 5a End surface 5b Rolling surface 6 Cage

Claims (1)

[Claims] 1. In a rolling bearing having a flange surface, the surface roughness of at least one of the flange surface or the end surface of the rolling element in contact with the flange is the roughness of the inner / outer ring raceway surface and the rolling surface of the rolling element. With respect to, a rolling bearing characterized by having the following relationship. 2 (σ ₁ ² + σ ₂ ² ) ^1/2 <(σ ₃ ² + σ ₄ ² ) ^1/2 <4 (σ
₁ ² + σ ₂ ² ) ^1/2 where σ ₁ ; inner / outer ring raceway surface roughness (center line average roughness) σ ₂ ; rolling element raceway surface roughness σ ₃ ; inner / outer ring rib surface roughness σ ₄ ; Roughness of end face of rolling element