Information
-
Patent Grant
-
6640933
-
Patent Number
6,640,933
-
Date Filed
Tuesday, July 10, 200123 years ago
-
Date Issued
Tuesday, November 4, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Joyce; William C
- McAnulty; Timothy
Agents
-
CPC
-
US Classifications
Field of Search
US
- 184 51
- 184 623
- 184 1051
- 384 462
- 384 466
- 384 467
- 384 468
- 384 471
- 384 473
-
International Classifications
-
Abstract
A lubrication system is provided for use with a bearing including an outer race, an inner race, and bearing elements disposed therebetween. Rotation of the bearing and a shaft journaled thereby induces air movement having a first air velocity and a path adjacent the bearing. The lubrication system includes a structure providing a passageway through which a lubricant entrained in gas is delivered at a second velocity to the bearing. The lubrication system further includes a flow modifier disposed relative to the bearing and the structure to modify the first air velocity to promote movement of the lubricant into the bearing.
Description
TECHNICAL FIELD
The invention relates to lubrication of a bearing and more particularly to dispensing a lubricant entrained in a gas into the bearing to lubricate the bearing. The invention is disclosed in the context of lubricating a bearing of a gas turbine engine. The invention is believed to be useful in other applications as well.
BACKGROUND AND SUMMARY
Lubrication systems for application to rotary elements, such as bearings, are known. See, for example, U.S. Pat. Nos. 2,986,433; 3,004,806; 4,502,274; 4,621,710; 5,113,818; 5,207,291; 5,251,725; 5,301,771; 5,404,964; 5,439,361; 6,098,583. The disclosures of those references are hereby incorporated herein by reference. No representation is intended that a complete search has been made of the prior art or that no better art than that listed is available, and no such representation should be inferred. This listing shall not be construed to be an admission that the listed references are, or are considered to be, material to patentability.
Some lubrication systems use gas-entrained lubricant to lubricate bearings coupled to a shaft. For example, mist lubrication systems use gas-entrained lubricant but are generally limited to applications characterized by a Dn value of less than or equal to 2.0 million millimeters-revolutions per minute (or mm-rpm), wherein Dn is defined as the product of the bearing bore diameter measured in millimeters and the angular velocity of the shaft measured in revolutions per minute. This is because rotation of the bearing and the shaft in Dn applications above 2.0 million mm-rpm induces a chaotic, turbulent flow field adjacent the bearing, thereby threatening ingress of low-momentum, gas-entrained lubricant particles into the bearing. Thus, it is desirable to have a lubrication system configured to lubricate a bearing using gas-entrained lubricant in high Dn applications above 2.0 million mm-rpm.
A lubrication system is disclosed herein for use with a bearing comprising an outer race, an inner race, and bearing elements disposed therebetween. Rotation of the bearing and a shaft journaled thereby about a central axis induces air movement having a first air velocity and a path adjacent the bearing. The lubrication system comprises a structure providing a passageway through which gas-entrained lubricant is delivered at a second velocity to the bearing and a flow modifier disposed relative to the bearing and the structure to modify the first air velocity to promote movement of the lubricant into the bearing.
In illustrative embodiments, the lubrication system further comprises a lubricant dispenser configured to dispense gas-entrained lubricant through an outlet into the bearing. The flow modifier is configured to slow the first air velocity relative to the velocity of the gas-entrained lubricant so that the gas-entrained lubricant dispensed from the outlet reaches the bearing to lubricate the bearing. The flow modifier comprises a screen structure comprising first baffles arranged in series about the shaft and a pair of second baffles coupled to at least one of the first baffles. The second baffles cooperate to define a space therebetween in which the outlet is disposed.
The present invention comprises, therefore, a screen structure disposed adjacent a bearing to modify the induced air flow. Illustratively, the screen structure will slow the induced air flow. Preferably, the screen structure will slow the induced air flow so that the velocity of the induced air flow is less than or equal to the velocity of the gas-entrained lubricant. The screen structure is provided with spaces into which nozzles are disposed. The nozzles are configured to dispense the gas-entrained lubricant onto the inner race of the bearing. The first baffles are disposed in the flow field of the induced air flow and are provided with a plurality of apertures through which the induced air movement can flow.
Illustratively, each second baffle comprises a base provided with a plurality of apertures through which the induced air movement can flow and a tang coupled to the base and extending toward the bearing. In illustrative embodiments, each tang is configured to block the flow of the induced air movement through the tang. In other illustrative embodiments, each tang is provided with a plurality of apertures through which the induced air movement can flow. Each nozzle is disposed between a pair of tangs.
Additional features and advantages of the infant care unit will become apparent to those skilled in the art upon consideration of the following detailed descriptions exemplifying the best mode of carrying out the apparatus as presently perceived.
BRIEF DESCRIPTION OF THE DRAWINGS
The illustrative apparatus will be described hereinafter with reference to the attached drawings which are given as non-limiting examples only, in which:
FIG. 1
is an exploded perspective view of an apparatus comprising a lubrication system comprising a flow modifier and lubricant dispensers, a bearing, a shaft, and a test rig;
FIG. 2
is a side elevation and partial cross-sectional view of the apparatus of
FIG. 1
;
FIG. 3
is an enlarged side elevation and partial cross-sectional view of the apparatus of
FIG. 2
;
FIG. 4
is an elevation view taken along lines
4
—
4
of
FIG. 2
showing the flow modifier in cross-section;
FIG. 5
is an elevation view of another embodiment of the flow modifier of FIG.
4
.
Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates an embodiment of the apparatus and such exemplification is not to be construed as limiting the scope of this application in any manner.
DETAILED DESCRIPTION OF THE DRAWINGS
A lubrication system
10
using air-entrained oil lubricant for elasto-hydrodynamic film lubrication of a bearing
12
coupled to a rotatable shaft
13
is shown, for example, in
FIGS. 1-4
. Lubrication system
10
includes a supply
14
of air-entrained lubricant, four lubricant dispensers or nozzles
16
configured to dispense individual jets
17
of the air-entrained lubricant at a lubricant velocity onto an inner race
18
of bearing
12
to lubricate bearing
12
, and a screen structure or flow modifier
20
disposed in an interior region
22
about shaft
13
and adjacent bearing
12
, as shown, for example, in
FIGS. 1-3
.
In illustrative embodiments, bearing
12
is an auxiliary or “back-up” bearing of a magnetic suspension system of a gas turbine engine and lubrication system
10
is configured to lubricate bearing
12
while on board the gas turbine engine. In this application, bearing
12
and shaft
13
are designed to operate at a high Dn value of 2.3 million mm-rpm in a 500° F. environment. In the absence of flow modifier
20
, such rotation of bearing
12
and shaft
13
induces chaotic, turbulent air movement (or windage) having an air velocity and a path adjacent bearing
12
which impedes ingress of low-momentum, air-entrained lubricant particles into bearing
12
. The induced air movement includes an air flow path that is adjacent bearing
12
and, while often somewhat chaotic, is generally circumferential about a central axis
54
.
Flow modifier
20
is designed to accommodate this high Dn application. Flow modifier
20
is disposed in interior region
22
adjacent bearing
12
, as shown, for example, in
FIGS. 2-4
. This is to modify the air movement induced by rotation of bearing
12
and shaft
13
to promote ingress of the low-momentum, air-entrained lubricant particles from nozzle outlets
24
through a jet space
26
between nozzle outlets
24
and inner race
18
onto inner race
18
. Jets
17
of the low-momentum, air-entrained lubricant particles are generally orthogonal to the circumferential air flow path of the induced air movement. Flow modifier
20
is configured to reduce the air velocity relative to the lubricant velocity so that the lubricant velocity is about equal to or greater than the air velocity. It is believed that flow modifier also somewhat streamlines the induced air movement.
Bearing
12
includes an outer ring
28
including an outer race
30
, an inner ring
32
including inner race
18
, and bearing elements
33
including balls
34
and a separator
36
, as shown, for example, in
FIGS. 2 and 3
. Balls
34
and ball separator
36
are disposed in a bearing space
38
defined by outer and inner rings
28
,
32
. In preferred embodiments, bearing
12
is an angular contact bearing.
Lubrication system
10
and bearing
12
are shown, for example, in
FIGS. 1-5
as being coupled to a test rig
40
designed to model gas turbine engine components associated with lubrication system
10
and bearing
12
. Rig
40
includes shaft
13
, an engine sump or bearing housing
42
, a bearing retainer plate
44
, and a support
46
.
Shaft
13
includes a shaft central body
48
and a shaft collar
50
fixed to shaft central body
48
and interconnecting shaft central body
48
and inner ring
32
, as shown, for example, in FIG.
2
. Inner ring
32
defines a shaft-receiving bore
52
having a bore diameter
53
and shaft
13
is disposed in shaft-receiving bore
52
. Inner ring
32
is fixed to shaft collar
50
to rotate with shaft
13
about central axis
54
extending through shaft central body
48
.
Outer ring
28
abuts an inner surface
56
of bearing housing
42
and is fixed to bearing retainer plate
44
, as shown, for example, in
FIGS. 2 and 3
. Bearing retainer plate
44
, in turn, is fixed to bearing housing
42
to fix outer ring
28
to bearing housing
42
. Bearing retainer plate
44
includes an axially extending sleeve
58
fixed to outer ring
28
and a flange
60
extending radially outwardly from sleeve
58
and fixed to bearing housing
42
by bolts
62
.
Support
46
is configured to support flow modifier
20
in interior region
22
so that flow modifier
20
is centered on central axis
54
, as shown, for example, in
FIGS. 2 and 3
. Support
46
includes an axially extending sleeve
66
and a flange
68
extending radially outwardly from sleeve
66
. Sleeve
66
defines interior region
22
in which flow modifier
20
is disposed. Sleeve
66
includes an axially inner section
70
disposed radially inwardly of and in contact with sleeve
58
of bearing retainer plate
44
and an axially outer section
72
. Flange
68
is disposed between inner and outer sections
70
,
72
and, along with flange
60
of bearing retainer plate
44
, is fixed to bearing housing
42
by bolts
62
.
Bearing retainer plate
44
and support
46
cooperate to form a nozzle holder
74
configured to hold nozzles
16
in position to dispense air-entrained lubricant into bearing
12
, as shown, for example, in
FIGS. 1-3
. Nozzle holder
74
cooperates with nozzle-receiving grooves
76
formed in bearing housing
42
to form four nozzle-receiving channels
78
configured to position nozzles
16
at 90° intervals circumferentially about central axis
54
. Sleeve
58
of bearing retainer plate
44
is formed to include nozzle-receiving apertures
80
. Flange
60
of bearing retainer plate
44
is formed to include nozzle-receiving apertures
82
. Inner sleeve section
70
of support
46
is formed to include nozzle-receiving apertures
84
. Flange
68
of support
46
is formed to include nozzle-receiving apertures
86
. Each of nozzle-receiving apertures
80
,
82
,
84
,
86
is sized to receive one of nozzles
16
. Nozzle-receiving apertures
80
,
82
,
84
,
86
cooperate with respective nozzle-receiving grooves
76
to form nozzle-receiving channels
78
. Each nozzle
16
is disposed in one of nozzle-receiving channels
78
.
Each nozzle
16
is disposed in fluid communication with air-entrained lubricant supply
14
and is oriented by nozzle holder
74
to dispense the air-entrained lubricant onto inner race
18
for lubrication of bearing
12
, as shown, for example, in
FIGS. 1-3
. Each nozzle
16
is formed to includes a passageway
88
and includes a nozzle body
90
including a larger diameter
92
, a nozzle throat
94
including a smaller diameter
96
and one of nozzle outlets
24
, and a reducer
98
interconnecting nozzle body
90
and nozzle throat
94
. Each nozzle
16
is configured to accelerate the air-entrained lubricant through its nozzle throat
94
to dispense the air-entrained lubricant from its nozzle outlet
24
at a lubricant velocity. Each nozzle throat
94
defines a nozzle throat axis
100
which is angled relative to central axis
54
. In preferred embodiments, each nozzle throat axis
100
is angled to permit lubricant to enter bearing
12
on central axis
54
.
Flow modifier
20
is disposed in interior region
22
and is fixed to support
46
, as shown, for example, in
FIGS. 2-4
. Flow modifier
20
includes a perforated structure
111
including four perforated first baffles or panels
112
configured to inhibit the induced air movement to slow the air velocity, as shown, for example, in
FIGS. 1-4
. Each panel
112
is generally planar and rectangle-shaped and is disposed generally parallel to central axis
54
. Adjacent panels
112
are disposed generally perpendicularly to one another and are coupled together along an edge
114
. Each edge
114
is generally parallel to central axis
54
and coupled to sleeve
66
to position and support flow modifier
20
in interior region
22
.
Panels
112
are arranged in series about shaft
13
and central axis
54
. Panels
112
cooperate with one another to form an outer boundary of a shaft-receiving interior region
116
in which shaft
13
is disposed for rotation. Each panel
112
is formed to include apertures
118
permitting the induced air movement to flow therethrough in a somewhat streamlined, ordered fashion. In preferred embodiments, each panel
112
is a perforated plate.
Flow modifier
20
further includes four pairs of second baffles or fins
120
coupled to sleeve
66
, as shown, for example, in
FIGS. 1-4
. Fins
120
are also configured to inhibit the induced air movement to slow the air velocity. Each pair of fins
120
is coupled to one of panels
112
so that the fin pairs are spaced at 90° intervals about central axis
54
. Each fin
120
is disposed generally perpendicularly to respective panel
112
to which it is coupled and is disposed outside of shaft-receiving interior region
116
. Each fin extends outwardly away from central axis
54
and axially relative to central axis
54
toward bearing
12
. Fins
120
of each fin pair are disposed in spaced-apart, generally parallel relation to one another. In preferred embodiments, each fin
120
is a perforated screen.
Each fin
120
includes a perforated base
122
coupled to one of panels
112
and a tang
124
coupled to perforated base
122
, as shown, for example, in
FIGS. 1-3
. Each of perforated base
122
and tang
124
is generally rectangle-shaped. Each perforated base
122
is formed to include apertures
130
permitting the induced air movement to pass through apertures
130
in a somewhat streamlined, ordered fashion.
Each tang
124
extends away from respective perforated base
122
toward bearing
12
, as shown, for example, in
FIGS. 1-3
. Tangs
124
of each fin pair cooperate with one another to define a nozzle-receiving space
128
in which one of nozzle throats
94
is disposed.
Each tang
124
includes a perforated member
125
coupled to and disposed in generally co-planar relation with perforated base
122
and a cover
126
fixed to perforated member
125
to close apertures
132
formed in perforated member
125
to block the induced air movement from passing through tang
124
, as shown, for example, in
FIGS. 1-4
. Apertures
132
are closed to promote movement of the air-entrained lubricant from respective nozzle outlet
24
through respective jet space
26
to inner race
18
, as shown, for example, in FIG.
3
. In preferred embodiments, covers
126
are removed from perforated members
125
to expose apertures
132
to the air induced movement for passage of the air induced movement therethrough, as shown, for example, in FIG.
5
.
Although the foregoing embodiments have been described, one skilled in the art can easily ascertain the essential characteristics of the apparatus, and various changes and modifications may be made to adapt the various uses and characteristics without departing from the spirit and scope of this application, as described by the claims which follow.
Claims
- 1. A lubrication system for use with a bearing comprising an outer race, an inner race, and bearing elements disposed therebetween, the bearing defining a central axis, rotation of the bearing and a shaft journaled thereby inducing air movement having a first air velocity and a path adjacent the bearing, the lubrication system comprising:a structure providing a passageway through which a lubricant entrained in gas is delivered at a second velocity to the bearing, a flow modifier disposed relative to the bearing and the structure to modify the first air velocity to promote movement of the lubricant into the bearing, and wherein the flow modifier includes a screen structure to inhibit the induced air movement, thereby reducing the first air velocity.
- 2. The lubrication system of claim 1, wherein the screen structure includes a perforated plate that inhibits the induced air movement so that the second velocity of the lubricant is at least as great as the first air velocity.
- 3. The lubrication system of claim 1, wherein the screen structure comprises first baffles arranged in series about the bearing axis in the path of the induced air movement.
- 4. The lubrication system of claim 3, wherein the screen structure comprises a pair of second baffles associated with at least one first baffle and disposed in the path of the induced air movement, the pair of second baffles being coupled to the at least one first baffle to extend outwardly relative to the central axis.
- 5. The lubrication system of claim 4, comprising a nozzle through which the lubricant exits to flow to the bearing, the second baffles being spaced apart to define a space in which the nozzle is disposed.
- 6. The lubrication system of claim 5, wherein the nozzle defines a nozzle axis extending at an angle to the bearing axis.
- 7. The lubrication system of claim 6, wherein each of the second baffles comprises a tang extending axially relative to the central axis and toward the bearing.
- 8. The lubrication system of claim 7, wherein the nozzle is disposed between the tangs.
- 9. The lubrication system of claim 4, wherein each of the second baffles is disposed in generally perpendicular relation to the at least one first baffle.
- 10. The lubrication system of claim 3, wherein each of the first baffles is configured to include apertures permitting the induced air movement to pass therethrough.
- 11. The lubrication system of claim 3, wherein each of the first baffles is generally planar and is disposed in generally parallel relation to the central axis.
- 12. A lubrication system for use with a bearing comprising an outer race, an inner race, and bearing elements disposed therebetween, the bearing defining a central axis, rotation of the bearing and a shaft journaled thereby inducing air movement having a first circumferential air velocity in a path adjacent the bearing, the lubrication system comprising:a structure providing a passageway through which a lubricant entrained in gas is delivered at a second velocity to the bearing, and a mechanical flow modifier disposed in the path adjacent to the bearing to reduce the first circumferential air velocity in the path to promote movement of the lubricant into the bearing.
- 13. An apparatus comprising:a shaft configured to rotate about a central axis, a bearing including an outer race, an inner race, and bearing elements disposed in a space between the outer and inner races, rotation of the bearing and the shaft journaled thereby about the central axis inducing air movement having a first circumferential air velocity in a path adjacent the bearing, and a nozzle disposed to dispense a lubricant entrained in gas at a second velocity into the space between the outer and inner races, and a mechanical flow modifier disposed in the path adjacent to the bearing to reduce the first circumferential air velocity in the path relative to the second velocity to promote movement of the gas-entrained lubricant into the bearing for lubrication of the bearing.
- 14. The apparatus of claim 13 wherein the bearing is formed to include a bore through which the shaft extends, the bore defines a bore diameter, the shaft rotates at an angular velocity, and the product of the bore diameter measured in millimeters and the angular velocity measured in revolutions per minute is at least 2.3 million millimeters-revolutions per minute.
- 15. An apparatus comprising:a shaft configured to rotate about a central axis, a bearing including an outer race, an inner race, and bearing elements disposed in a space between the outer and inner races, rotation of the bearing and the shaft journaled thereby about the central axis inducing air movement having a first air velocity and a path adjacent the bearing, a nozzle disposed to dispense a lubricant entrained in gas at a second velocity into the space between the outer and inner races, a flow modifier disposed relative to the bearing and the nozzle to modify the first air velocity relative to the second velocity to promote movement of the gas-entrained lubricant into the bearing for lubrication of the bearing, and wherein the flow modifier includes a screen structure that inhibits the induced air movement.
- 16. An apparatus comprising:a shaft configured to rotate about a central axis, a bearing including an outer race, an inner race, and bearing elements disposed in a space between the outer and inner races, rotation of the bearing and the shaft journaled thereby about the central axis inducing air movement having a first air velocity and a path adjacent the bearing, a nozzle disposed to dispense a lubricant entrained in gas at a second velocity into the space between the outer and inner races, a flow modifier disposed relative to the bearing and the nozzle to modify the first air velocity relative to the second velocity to promote movement of the gas-entrained lubricant into the bearing for lubrication of the bearing, and wherein the flow modifier includes first baffles arranged in series about the central axis in the path of the induced air movement.
- 17. The apparatus of claim 16, wherein the flow modifier further includes a pair of second baffles disposed in the path of the induced air movement and coupled to one of the first baffles and the second baffles cooperate with one another to define a nozzle-receiving space in which the nozzle is disposed.
- 18. The apparatus of claim 17, wherein each of the second baffles comprises a tang extending toward the bearing and the nozzle is disposed between the tangs.
- 19. The apparatus of claim 18, wherein each of the second baffles comprises a base coupled to the tang of the respective second baffle and the base is configured to include apertures permitting the induced air movement to pass therethrough.
- 20. The apparatus of claim 17, wherein each of the second baffles is disposed generally perpendicularly to the one of the first baffles.
- 21. The apparatus of claim 16, wherein each of the first baffles is configured to include apertures permitting the induced air movement to pass therethrough.
- 22. The apparatus of claim 16, wherein each of the first baffles is generally planar and is disposed generally parallel to the central axis.
- 23. An apparatus comprising:a shaft configured to rotate about a central axis, a bearing disposed about the central axis and including an outer race, an inner race coupled to the shaft and cooperating with the outer race to form a first space therebetween, and bearing elements disposed in the first space to permit rotation of the inner race relative to the outer race about the central axis, rotation of the bearing and the shaft about the central axis inducing air movement having a first air velocity and a path adjacent the bearing, lubricant dispensers spaced apart about the central axis, each lubricant dispenser being configured to include a passageway through which lubricant entrained in air flows and an outlet spaced apart from the bearing to define a second space therebetween and to dispense the air-entrained lubricant at a second velocity from the outlet into the second space toward the inner race, and a screen structure including first baffles arranged in series about the central axis and pairs of second baffles, each pair of second baffles being coupled to one of the first baffles and forming a third space, each of the outlets being disposed in one of the third spaces so that the air-entrained lubricant dispensed from the outlets reaches the inner race to lubricate the bearing.
- 24. The apparatus of claim 23, wherein each of the first baffles is disposed generally parallel to the shaft axis and each of the second baffles is disposed generally perpendicular to the first baffle to which it is coupled.
- 25. The apparatus of claim 23, wherein the first baffles cooperate with one another to define an outer boundary of an interior region, the shaft extends through the interior region, and each of the pairs of second baffles is disposed outside of the interior region.
- 26. The apparatus of claim 23, wherein each of the second baffles comprises a tang extending axially relative to the central axis and each outlet is disposed between the tangs of one of the pairs of second baffles.
- 27. The apparatus of claim 26, wherein each tang is configured to include apertures permitting the induced air movement therethrough.
- 28. The apparatus of claim 23, wherein the lubricant dispensers are spaced at about 90° intervals about the central axis.
- 29. The apparatus of claim 23, wherein the bearing is formed to include a bore through which the shaft extends, the bore defines a bore diameter, the shaft rotates at an angular velocity, and the product of the bore diameter measured in millimeters and the angular velocity measured in revolutions per minute is at least 2.3 million millimeters-revolutions per minute.
US Referenced Citations (16)
Foreign Referenced Citations (2)
Number |
Date |
Country |
369878 |
May 1990 |
EP |
8-284961 |
Nov 1996 |
JP |