U.S. patent application number 13/232959 was filed with the patent office on 2012-03-15 for transmission pump.
This patent application is currently assigned to EATON CORPORATION. Invention is credited to Jerry J. Brittan, Robert B. Craft, Paul J. Mason.
Application Number | 20120061184 13/232959 |
Document ID | / |
Family ID | 45805581 |
Filed Date | 2012-03-15 |
United States Patent
Application |
20120061184 |
Kind Code |
A1 |
Craft; Robert B. ; et
al. |
March 15, 2012 |
Transmission Pump
Abstract
This invention provides both a pump and a lubrication and
cooling system with a pump which includes a pump housing, a rotor,
a relief valve and a bypass valve. The relief valve is configured
to relieve pump pressure when the pump pressure is indicative of an
abnormal restriction of flow. The bypass valve is configured to
direct fluid flow from an outlet chamber of the pump to an intake
chamber of the pump when pressure in the outlet chamber is at a
value associated with a predetermined speed of rotor rotation.
Inventors: |
Craft; Robert B.; (Ceresco,
MI) ; Mason; Paul J.; (Bellevue, MI) ;
Brittan; Jerry J.; (Mattawan, MI) |
Assignee: |
EATON CORPORATION
Cleveland
OH
|
Family ID: |
45805581 |
Appl. No.: |
13/232959 |
Filed: |
September 14, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61382603 |
Sep 14, 2010 |
|
|
|
Current U.S.
Class: |
184/6.12 ;
418/166 |
Current CPC
Class: |
F16N 13/22 20130101;
F16N 13/20 20130101; F04C 2/102 20130101; F04C 14/28 20130101; F16H
57/0412 20130101; F16H 57/0435 20130101; F01M 2001/0238 20130101;
F04C 14/26 20130101; F04C 2/105 20130101; F16H 57/0436 20130101;
F04C 14/16 20130101; F01M 1/20 20130101; F16H 57/0404 20130101 |
Class at
Publication: |
184/6.12 ;
418/166 |
International
Class: |
F16H 57/04 20100101
F16H057/04; F16N 13/20 20060101 F16N013/20; F16N 13/22 20060101
F16N013/22; F01C 1/10 20060101 F01C001/10 |
Claims
1. A pump comprising: a pump housing defining a suction port, an
outlet port, a rotor chamber disposed between the suction port and
the outlet port, an intake chamber fluidly connected to the suction
port, an inlet chamber fluidly connected to the intake chamber and
fluidly connected to the rotor chamber, an outlet chamber fluidly
connected to the rotor chamber and fluidly connected to the outlet
port; a rotor rotatably disposed in the rotor chamber having a
first portion in fluid communication with the outlet chamber and
having a second portion in fluid communication with the inlet
chamber; a relief valve operably disposed between the outlet
chamber and a relief port though the housing and configured to
operably fluidly connect the outlet chamber with the relief port
when a pressure in the outlet chamber is at or above a first value
indicative of an abnormal restriction of flow from the outlet
chamber; and a bypass valve operably disposed between the outlet
chamber and the intake chamber and configured to operably fluidly
connect the outlet chamber with the intake chamber when the
pressure in the outlet chamber is at or above a second value less
than the first value and indicative of a pressure in the outlet
chamber at or above a pressure associated with a predetermined
speed of rotation of the rotor.
2. A pump as claimed in claim 1 wherein a restrictive orifice is
disposed between the outlet chamber and the bypass valve.
3. A pump as claimed in claim 1 wherein the relief valve includes a
relief check ball and a spring biasing the relief check ball to a
closed position and the bypass valve includes a bypass check ball
and a spring biasing the bypass check ball to a closed
position.
4. A pump as claimed in claim 3 wherein the bypass valve includes a
travel limit pin configured to limit the displacement of bypass
check ball away from a seated position.
5. A lubrication and cooling system for a transmission comprising:
a pump including: a pump housing defining a suction port, an outlet
port; a rotor chamber disposed between the suction port and the
outlet port, an intake chamber fluidly connected to the suction
port, an inlet chamber fluidly connected to the intake chamber and
fluidly connected to the rotor chamber, an outlet chamber fluidly
connected to the rotor chamber and fluidly connected to the outlet
port; a rotor rotatably disposed in the rotor chamber having a
first portion in fluid communication with the outlet chamber and
having a second portion in fluid communication with the inlet
chamber; a relief valve operably disposed between the outlet
chamber and a relief port though the housing and configured to
operably fluidly connect the outlet chamber with the relief port
when a pressure in the outlet chamber is at or above a first value
indicative of an abnormal restriction of flow from the outlet
chamber; and a bypass valve operably disposed between the outlet
chamber and the intake chamber and configured to operably fluidly
connect the outlet chamber with the intake chamber when the
pressure in the outlet chamber is at or above a second value less
than the first value and indicative of a pressure in the outlet
chamber at or above a pressure associated with a predetermined
speed of rotation of the rotor a lubrication and cooling fluid
circuit including a cooling and filtering channel on which a cooler
and a filter are operably disposed and fluidly connecting the
outlet port of the pump with a lubrication channel; the lubrication
channel configured to distribute fluid to predetermined points
within the transmission; and a relief channel fluidly connecting
the relief port to the lubrication channel.
6. A lubrication and cooling system as claimed in claim 5 wherein a
restrictive orifice is disposed between the outlet chamber and the
bypass valve.
7. A lubrication and cooling system as claimed in claim 7 wherein
the relief valve includes a relief check ball and a spring biasing
the relief check ball to a closed position and the bypass valve
includes a bypass check ball and a spring biasing the bypass check
ball to a closed position.
8. A lubrication and cooling system as claimed in claim 7 wherein
the bypass valve includes a travel limit pin configured to limit
the displacement of bypass check ball away from a seated position.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/382,603, filed Sep. 14, 2010, which is hereby
incorporated by reference in their entireties.
BACKGROUND OF THE INVENTION
[0002] It is desired to provide a lubrication and cooling system
for a transmission and a pump for use in such a system which
responds to fluid flow restrictions that might occur in a cooler or
in a filter. It is also desired to provide such a system and pump
which is able to reduce the opportunity for pump cavitation at
elevated speeds pump speeds.
SUMMARY OF THE INVENTION
[0003] This invention provides both a pump and a lubrication and
cooling system with a pump which includes a pump housing, a rotor,
a relief valve and a bypass valve. The relief valve is configured
to relieve pump pressure when the pump pressure is indicative of an
abnormal restriction of flow. The bypass valve is configured to
direct fluid flow from an outlet chamber of the pump to an intake
chamber of the pump when pressure in the outlet chamber is at a
value associated with a predetermined speed of rotor rotation.
[0004] This invention also overcomes the pump cavitation at
elevated speeds by directing unneeded fluid flow directly from the
outlet chamber to an intake chamber by way of the bypass valve.
Flow of fluid to the lubrication system is maintained in the event
of a restriction in either a cooler or a filter by way of the
relief valve.
DESCRIPTION OF DRAWINGS
[0005] FIG. 1 is a schematic view of a transmission lubrication and
cooling system including a pump.
[0006] FIG. 2 is a perspective view of the pump of FIG. 1.
[0007] FIG. 3 is a perspective view of a housing of the pump of
FIG. 2.
[0008] FIG. 4 is a perspective view of a cover plate of the pump of
FIG. 2.
[0009] FIG. 5 is a perspective view of a rotor of the pump of FIG.
2.
[0010] FIG. 6 is a perspective view of a pump idler of FIG. 2.
[0011] FIG. 7 is a top view of the pump of FIG. 2.
[0012] FIG. 8 is a rear view of the pump of FIG. 2.
[0013] FIG. 9 is a rear view of the pump of FIG. 8 with the cover
plate removed.
[0014] FIG. 10 is a sectional view of the pump of FIG. 8 in the
direction of arrows 10.
[0015] FIG. 11 is a sectional view of the pump of FIG. 7 in the
direction of arrows 11.
DETAILED DESCRIPTION OF THE INVENTION
[0016] The terms top, bottom, and other directional terms such as
front, rear, upper and lower are only used to provide the relative
orientation of surfaces and features of the components and system,
and are not indicative of the absolute position or orientation of
any component or feature.
[0017] FIG. 1 shows a transmission lubrication and cooling system
20 including a lubrication and cooling circuit 22, a pump 24 and a
sump 26. A suction channel 28 is disposed between and fluidly
connects sump 26 and pump 24. A cooler 30 and a filter 32 are
fluidly connected to pump 24 by cooling and filter channel 34. A
lubrication channel 36 is connected to cooling and filter channel
34. Lubrication channel 36 serves as a conduit of fluid to
lubrication system 38. An optional return channel 40 may be used to
return fluid to sump 26.
[0018] Pump 24 includes a relief valve 42 and a bypass valve 44.
Both valves 42 and 44 are incorporated into a housing 46 of pump
24. A cover plate 48 is disposed on a rear or back side of pump
housing 46. Cover plate 48 defines outlet port 50.
[0019] A suction port 52 of pump 24 is connected to sump 26 by
suction channel 28. The illustrated pump is a gerotor style pump,
and includes a pump rotor or inner rotor 54 and a pump idler or
outer rotor 56, both of which are disposed inside of pump housing
46. As suggested by the figures which variously show rotor 54
having four lobes and idler 56 having five teeth, and rotor 54
having five lobes and idler 56 having six teeth, the invention is
not intended to be limited to pumps having a particular count of
meshing features. A pump shaft 58 is rotatably fixed to pump rotor
54 by a key (not shown) or equivalent means. Pump shaft 58 rotates
about an axis of rotation 60 normal to the pump rotor 54. A drive
gear 62 is disposed outside of housing 46 and is rotatably fixed to
shaft 58 by a key or equivalent means. Drive gear 62 is an
exemplary means by which torque and speed is transferred to shaft
58 and rotor 54. The illustrated drive means is not intended to be
limiting.
[0020] Housing 46 includes a rotor chamber 64 in which each of
rotor 54 and idler 56 are disposed. Other features of housing 46
include an intake chamber 66 which connects directly to suction
port 52 and a pump inlet chamber 68 which is fluidly connected with
and open to rotor chamber 64. Additionally, an outlet chamber 70 is
fluidly connected with both rotor chamber 64 and outlet port
50.
[0021] As best seen in FIG. 11, relief valve 42 is operably
disposed between an outlet chamber 70 and a relief port 72. A
plurality of ports 72 may be provided. Valve 42 is configured to
open to operably fluidly connect outlet chamber 70 with relief port
72. In the embodiment illustrated, a relief valve plug 74 is
disposed in housing 46 to retain relief valve bias spring 76.
Spring 76 biases relief valve check ball 78 against relief valve
ball seat 80. A relief channel 82 fluidly connects relief port 72
with lubrication channel 36.
[0022] Bypass valve 44 is operably disposed between outlet chamber
70 and intake chamber 66. Valve 44 is fluidly connected to intake
chamber 66 by a bypass channel 84. A bypass passage 86 fluidly
connects valve 44 with outlet chamber 70. Valve 44 is configured to
open to operably fluidly connect outlet chamber 70 with intake
chamber 66. In the embodiment illustrated, a bypass valve plug 88
is disposed in housing 46 to retain bypass valve bias spring 90.
Spring 90 biases bypass valve check ball 92 against bypass valve
ball seat 94. Passage 86 defines a restrictive orifice through
which fluid reaching valve 44 must pass. A travel limit pin 96 may
electively be configured to limit the displacement of check ball 92
from seat 94 is disposed in housing 46. Pin 96 may be formed as
part of plug 88, or may be a separate component.
[0023] A description of the invention operation follows. Pump 24
relies on a conventional gerotor arrangement to draw and pressurize
its operating fluid. The operation of such pumps is well known and
illustrated in references such as U.S. Pat. No. 4,041,703. In a
first condition, at relatively low rotational speeds of shaft 58
and rotor 54, with no abnormal restrictions in cooling and
filtering channel 34, each of relief valve 42 and bypass valve 44
are in a closed condition, with all of the fluid displaced by the
rotation of rotor 54 being drawn from sump 26 through suction
channel 28 and passing through outlet port 50, through cooler 30
and filter 32 and lubrication system 38. Examples of conditions
constituting an abnormal restriction include a plugged or partially
plugged cooler 30, and a plugged or partially plugged filter 32. An
abnormal restriction might also result from high fluid viscosity at
start-up due to a low ambient temperature.
[0024] In a second condition, at a first pressure within outlet
chamber 70 corresponding to a predetermined speed of rotor 54,
bypass valve 44 opens to allow operating fluid to flow from outlet
chamber 70 to intake chamber 66 where it joins fluid being drawn up
from sump 26 through channel 28. The quantity of fluid reaching
intake chamber beneficially helps avoid cavitation of the pump.
While alternative solutions might include increasing the sizing of
the suction channel and optimizing the location of the pump
relative to the sump, the present invention enables greater
flexibility in the location of the pump. The restriction provided
by the orifice sizing of passage 86 reduces the rate of flow to the
intake chamber. The combination of spring selection and orifice
sizing enable one skilled in the art to provide a pressure and flow
combination suited for the application at hand. Intake chamber 66
has a greater cross sectional area in the flow direction than
suction channel 28, accommodating the additional volumetric flow
past bypass valve 44 and facilitating an increased volumetric flow
into adjoining inlet chamber 66 which feeds operating fluid to
rotating rotor 54. All of the pressurized operating fluid in outlet
provided by the rotation of rotor 54, excepting that which travels
past valve 44, exits through outlet port 50 and passes through
cooler 30, filter 32 and lubrication system 38. An exemplary range
of pressure at which valve 44 opens is 67 pounds per square inch
(psi) to 71 psi.
[0025] In a third condition, as the operating fluid within outlet
chamber 70 reaches a second pressure indicative of an abnormal
restriction of flow in cooling and filtering channel 34, relief
valve 42 opens to allow operating fluid to flow from outlet chamber
70 to lubrication system 38 via relief channel 82. Routing the flow
from the relief valve to the lubrication system instead of directly
to the sump enables system 20 to maintain the flow of operating
fluid critical lubrication of the transmission, thereby avoiding
damage to the transmission. As in the second condition, operating
fluid flows past bypass valve 44. The amount of fluid, if any,
passing through cooler 30 and filter 32 will depend on the extent
of blockage. An exemplary range of pressure at which valve 42 opens
is 114 psi to 142 psi. The appropriate range of pressures for any
particular application of the inventive system will vary with that
application. Factors influencing pressure ranges for both the
bypass and relief valves include, but are not limited to, the
viscosity of the operating fluid, the anticipated operating
temperatures, and the anticipated back pressure of the system under
normal operating conditions.
[0026] The scope of the invention is set forth in the claims
below.
* * * * *