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Rolling bearing

Imported: 24 Feb '17 | Published: 13 Jan '04

Takayuki Miyagawa, Banda Noda, Yasuyuki Muto, Tatsunobu Momono

USPTO - Utility Patents

Abstract

The frequencies generated based on the undulations existing on the inner and outer ring raceways

8, 10 and on the rolling surface of the balls

11, 11 are out of coincidence with the rotational frequency itself of the rotation member supported by the rolling bearing, and with a frequency component which is a multiple of the rotational frequency, or kinds of frequencies generated due to the undulations are out of coincidence with each other in the natural frequency domain of a rotation system which is a rotation supporting portion having the rolling bearing incorporated therein, whereby without using a special grease, the self-excited frequency of the rolling bodies hardly grows to abnormal vibration, and a rolling bearing having sufficient durability and causing no abnormal vibration and noise even if used at low temperature is realized.

Description

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional view showing one example of a rotation supporting portion incorporating a rolling bearing, being an object of the present invention.

FIG. 2 is a Campbell chart representing vibration generated when a conventional rolling bearing is used.

FIG. 3 is a Campbell chart representing vibration generated when a rolling bearing in a first embodiment of the present invention is used.

FIG. 4 is a Campbell chart representing vibration generated when a rolling bearing in a second embodiment of the present invention is used.

Claims

1. A rolling bearing comprising a first race having a first raceway, a second race provided around the first race and having a second raceway, Z rolling bodies having a rolling surface and rollably disposed between the first raceway and the second raceway, and a retainer for holding the rolling bodies, such that under grease lubrication, the first race rotates at the frequency of f

r (Hz) while the rolling bodies held in the retainer rotate at the frequency of f

b (Hz) and revolve at the frequency of f

c (Hz), wherein, when assumed that n, m, k and j are each a positive integer up to 100, respectively, that D

a is the diameter of the rolling bodies, that dm is the pitch circle diameter of the rolling bodies, that is the contact angle between the rolling bodies and the first and second raceways and that vibration is generated at frequencies of mZf

i, mZf

i±f

r, nZf

c, 2kf

b and 2kf

b±f

c due to the circumferential undulations of (mZ) waves and (mZ+1) waves existing on the surface of the first raceway, to the circumferential undulations of (nZ) waves and (nZ±1) waves existing on the surface of the second raceway and to the undulation of (2k) waves existing on the rolling surface of the respective rolling bodies, the formulas of (mZf

j)≠jf

r, (mZf

i±f

r)≠jf

r, (nZf

c)≠jf

r, (2kf

b)≠jf

r and (2kf

b±f

c)≠jf

r are satisfied for all of n, m, k and j with respect to the frequencies, where f

i=f

r−f

c (Hz), nZf

c=(1/2)nf

r{1−(D

a/d

m)cos }Z, mZf

i=(1/2)mf

r{1+(D

a/d

m)cos }Z, and 2kf

b=kf

r{1−(D

a/d

m)

2cos

2 }d

m/D

a.

2. A rolling bearing comprising a first race having a first raceway, a second race provided around the first race and having a second raceway, Z rolling bodies having a rolling surface and rollably disposed between the first raceway and the second raceway, and a retainer for holding the rolling bodies, such that under grease lubrication, the first race rotates at the frequency of f

r (Hz) while the rolling bodies held in the retainer rotate at the frequency of f

b (Hz) and revolve at the frequency of f

c (Hz), wherein, when assumed that n, m, k and j are each a positive integer up to 100, respectively, that D

a is the diameter of the rolling bodies, that d

m is the pitch circle diameter of the rolling bodies, that is the contact angle between the rolling bodies and the first and second raceways and that vibration is generated at frequencies of mZf

i, mZf

i±f

r, nZf

c, 2kf

b and 2kf

b±f

c due to the circumferential undulations of (mZ) waves and (mZ±1) waves existing on the surface of the first raceway, to the circumferential undulations of (nZ) waves and (nZ±1) waves existing on the surface of the second raceway and to the undulation of (2k) waves existing on the rolling surface of the respective rolling bodies,

3. The rolling bearing of claim 2, wherein the formulas of nf

c/mf

i≧1.02, and nf

c/mf

i≦0.98 are satisfied, where nf

c/mf

i=(d

m−D

a)n/(d

m+D

a)m.

4. The rolling bearing of claim 2, wherein the natural frequency domain of the rotation system is in the range of F

n±250 (Hz) where F

n is the natural frequency which is determined by detecting an acceleration generated by impulse excitation of the rotation system by way of a hammer and processing the acceleration with FFT.

5. A rolling bearing comprising a first race having a first raceway, a second race provided around the first race and having a second raceway, Z rolling bodies having a rolling surface and rollably disposed between the first raceway and the second raceway, and a retainer for holding the rolling bodies, such that under grease lubrication, the first race rotates at the frequency of f

r (Hz) while the rolling bodies held in the retainer rotate at the frequency of f

b (Hz) and revolve at the frequency of f

c (Hz), wherein, when assumed that n, m, k and j are each a positive integer up to 100, respectively, that D

a is the diameter of the rolling bodies, that d

m is the pitch circle diameter of the rolling bodies, that is the contact angle between the rolling bodies and the first and second raceways and that vibration is generated at frequencies of mZf

i, mZf

i±f

r, nZf

c, 2kf

b and 2kf

b±f

c due to the circumferential undulations of (mZ) waves and (mZ±1) waves existing on the surface of the first raceway, to the circumferetial undulations of (nZ) waves and (nZ±1) waves existing on the surface of the second raceway and to the undulation of (2k) waves existing on the rolling surface of the respective rolling bodies, the formulas of (mZf

i)≠jf

r, (mZf

i±f

r)≠jf

r, (nZf

c)≠jf

r, (2kf

b)≠jf

r and (2kf

b±f

c)≠jf

r are satisfied for all of n, m, k and j with respect to the frequencies,

6. The rolling bearing of claim 5, wherein the formulas of nf

c/mf

i≦1.02, and nf

c/mf

i≦0.98 are satisfied, where nf

c/mf

i=(d

m−D

a)n/(d

m+D

a)m.

7. A method for design of the rolling bearing of claim 6 comprising the steps of:

8. The method of claim 7, where the diameter of the rolling bodies, the number of the rolling bodies and the pitch circle diameter of the rolling bodies are changed without changing the inner and outer diameters and the width of the ball bearing.

9. The rolling bearing of claim 5, wherein the natural frequency domain of the rotation system is in the range of F

n±250 (Hz) where F

n is the natural frequency which is determined by detecting an acceleration generated by impulse excitation of the rotation system by way of a hammer and processing the acceleration with FFT.