System and method for dynamically determining refrigerant film thickness and dynamically controlling refrigerant film thickness at rolling-element bearing of an oil free chiller

Patent metadata

Field	Value
Publication number	US-10317121-B2
Application number	US-201615383307-A
Country	US
Kind code	B2
Filing date	Dec 19, 2016
Priority date	Dec 17, 2015
Publication date	Jun 11, 2019
Grant date	Jun 11, 2019

Abstract

Methods are directed towards dynamically determining refrigerant film thickness at the rolling-element bearing and for dynamically controlling refrigerant film thickness at the rolling-element bearing. Further, an oil free chiller system is configured for dynamically determining refrigerant film thickness at the rolling-element bearing of the oil free chiller system, wherein the oil free chiller system is also configured for dynamically controlling refrigerant film thickness at the rolling-element bearing of the oil free chiller system.

First claim

What is claimed is:

1. A computerized controller device for an oil free chiller configured for dynamically determining an actual refrigerant film thickness at a bearing of the oil free chiller during operation of the oil free chiller, and for controlling other components of the oil free chiller to change a refrigerant film thickness at the bearing or an operation of the oil free chiller, when the actual refrigerant film thickness is different from a threshold refrigerant film thickness,
wherein the computerized controller device determines the actual refrigerant film thickness at the bearing of the oil free chiller during operation of the oil free chiller based only on temperature and rotation speed of the bearing.

2. The computerized controller device as in claim 1 , wherein the computerized controller device controls the other components of the oil free chiller so that the change of the refrigerant film thickness at the bearing is an increase of the refrigerant film thickness, when the actual refrigerant film thickness is below the threshold refrigerant film thickness.

3. The computerized controller device as in claim 1 , wherein the threshold refrigerant film thickness is a predetermined minimum refrigerant film thickness.

4. A computerized controller device for an oil free chiller configured for dynamically determining an actual refrigerant film thickness at a bearing of the oil free chiller during operation of the oil free chiller, and for controlling other components of the oil free chiller to change a refrigerant film thickness at the bearing or an operation of the oil free chiller, when the actual refrigerant film thickness is different from a threshold refrigerant film thickness, wherein the computerized controller device applies Formula 1 transformed to a computerized instruction set for performing a specialized function of determining the actual refrigerant film thickness (h actual):

h
actual

=

AR
⁡

(

1
-

e
Bk

)

⁡

[

Nv

ER
r

]

C

⁢

(

α
⁢

⁢
E

)

D

⁢

(

F

ER
r
2

)

G

Formula
⁢

⁢
1

wherein:
A, B, C, D, and G are constants;
e is the Euler's constant;
R r is a curvature radius of an inner bearing race;
R is a speed of rotation;
k is the Boltzmann constant;
E is a Young's Modulus;
F is a load parameter;
N is a dynamic viscosity;
v is a mean rolling velocity of a ball and the inner bearing race; and
αa is a pressure viscosity.

5. A computerized controller device for an oil free chiller configured for dynamically determining an actual refrigerant film thickness at a bearing of the oil free chiller during operation of the oil free chiller, and for controlling other components of the oil free chiller to change a refrigerant film thickness at the bearing or an operation of the oil free chiller, when the actual refrigerant film thickness is different from a threshold refrigerant film thickness, wherein the computerized controller device applies Formula 2 transformed to a computerized instruction set for performing a specialized function of determining the actual refrigerant film thickness (h actual ):

h
actual

=

HR
⁡

[

Nv

ER
r

]

I

⁡

[

F

ER
r
2

]

J

Formula
⁢

⁢
2

wherein:
H, I, and J are constants;
e is the Euler's constant;
R r is a curvature radius of an inner bearing race;
R is a speed of rotation;
E is a Young's Modulus;
F is a load parameter;
N is a dynamic viscosity; and
v is a mean rolling velocity of a ball and the inner bearing race.

6. An oil free chiller system, comprising the computerized controller device according to claim 1 , wherein the computerized controller device controls an operation o

Assignees

• Trane Int Inc

Inventors

• Johnson Jay H

Classifications

• F16C37/007

  of rolling bearings · CPC title

• F16C19/546

  Systems with spaced apart rolling bearings including at least one angular contact bearing · CPC title

• F25B2600/0253

  with variable speed · CPC title

• F16N29/00

  Special means in lubricating arrangements or systems providing for the indication or detection of undesired conditions; Use of devices responsive to conditions in lubricating arrangements or systems · CPC title

• F16N15/00

  Lubrication with substances other than oil or grease; Lubrication characterised by the use of particular lubricants in particular apparatus or conditions (F16N17/00 takes precedence; lubricating compositions, selection of particular substances as lubricants in general C10M) · CPC title