Detection method of state of bearing device, detection device, and program

Patent metadata

Field	Value
Publication number	US-12196639-B2
Application number	US-202118245124-A
Country	US
Kind code	B2
Filing date	May 31, 2021
Priority date	Sep 14, 2020
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A detection method for detecting a state of a bearing device including an outer member, an inner member, and a plurality of rolling elements, the detection method including: applying an alternating current voltage to an electric circuit including the outer member, the rolling element, and the inner member while a predetermined load is applied to the bearing device; measuring an impedance and a phase angle of the electric circuit applied with the alternating current voltage; and deriving an oil film thickness and a metal contact ratio between the inner member and the plurality of rolling elements or between the inner member and at least one of the plurality of rolling elements based on the impedance and the phase angle.

First claim

The invention claimed is:

1. A detection method for detecting a state of a bearing device including an outer member, an inner member, and a plurality of rolling elements, the detection method comprising:
applying an alternating current voltage to an electric circuit including the outer member, the rolling element, and the inner member while a predetermined load is applied to the bearing device;
measuring an impedance and a phase angle of the electric circuit applied with the alternating current voltage; and
deriving an oil film thickness and a metal contact ratio between the outer member and the plurality of rolling elements or between the inner member and at least one of the plurality of rolling elements based on the impedance and the phase angle,
wherein the predetermined load includes at least a radial load, and
wherein the oil film thickness and the metal contact ratio are derived by using a first calculation formula corresponding to an electric circuit configured in each of a loaded zone and an unloaded zone in the bearing device specified by the predetermined load.

2. The detection method according to claim 1 , wherein
the first calculation formula for deriving the oil film thickness h and the metal contact ratio α is as follows.

[

Equation
⁢

1

]

h
=

(

1
-
α

)

⁢
δ
/

(

(

δ

r
h

_

)

⁢

exp
⁡
(

1
-

ζ
⁡
(

sin
⁢
θ

ω
⁢

❘
"\[LeftBracketingBar]"

Z

❘
"\[RightBracketingBar]"

+

k
l

⁢

∑

m
=
1

n
-

n
1

C
3

(
m
)

)

)

)

⁢

α
=

❘
"\[LeftBracketingBar]"

Z
0

❘
"\[RightBracketingBar]"

⁢
cos
⁢
θ
/

❘
"\[LeftBracketingBar]"

Z

❘
"\[RightBracketingBar]"

⁢
cos
⁢

θ
0

3. The detection method according to claim 1 , wherein
the bearing device further includes a peripheral member,
the predetermined load includes at least a radial load, and
the oil film thickness and the metal contact ratio are derived by using a second calculation formula corresponding to an electric circuit configured in each of a loaded zone and an unloaded zone in the bearing device specified by the predetermined load and an electric circuit including the peripheral member.

4. The detection method according to claim 3 , wherein
the second calculation formula for deriving the oil film thickness and the metal contact ratio is as follows.

[

Equation
⁢

2

]

h
=

(

1
-
α

)

⁢
δ
/

(

(

δ

r
h

Assignees

• Nsk Ltd

Inventors

• Maruyama Taisuke
• Sugawara Suguru
• Maeda Masayuki

Classifications

• F16C19/52 Primary

  with devices affected by abnormal or undesired conditions · CPC title

• F16C33/6688

  Lubricant compositions or properties, e.g. viscosity · CPC title

• G01B7/06

  for measuring thickness {(measuring during the manufacture of coatings C23C14/54)} · CPC title

• F16C2233/00

  Monitoring condition, e.g. temperature, load, vibration · CPC title

• F16C33/6637

  with liquid lubricant · CPC title