U.S. patent application number 10/552208 was filed with the patent office on 2006-09-28 for heat exchanger integrated in a transmission.
Invention is credited to Gerhard Horing, Marcus Raeder, Roland Stauber.
Application Number | 20060213462 10/552208 |
Document ID | / |
Family ID | 33016170 |
Filed Date | 2006-09-28 |
United States Patent
Application |
20060213462 |
Kind Code |
A1 |
Horing; Gerhard ; et
al. |
September 28, 2006 |
Heat exchanger integrated in a transmission
Abstract
A transmission (8) has a transmission case (26) that comprises
an area in which the gear wheels (66, 68) rotate, and a heat
exchanger (30) that absorbs heat generated in the transmission (8)
and transferred to a transmission lubricant and conveys this heat
to a coolant for transporting the heat away from the transmission
(8). A recess (56), through which transmission lubricant flows and
in which the heat exchanger (30) is arranged, is provided in the
transmission case (26) outside the area in which the gear wheels
(66, 68) rotate.
Inventors: |
Horing; Gerhard; (Hagnau,
DE) ; Stauber; Roland; (Friedrichshafen, DE) ;
Raeder; Marcus; (Bermatingen, DE) |
Correspondence
Address: |
DAVIS & BUJOLD, P.L.L.C.
112 PLEASANT STREET
CONCORD
NH
03301
US
|
Family ID: |
33016170 |
Appl. No.: |
10/552208 |
Filed: |
April 2, 2004 |
PCT Filed: |
April 2, 2004 |
PCT NO: |
PCT/EP04/03491 |
371 Date: |
December 20, 2005 |
Current U.S.
Class: |
123/41.23 |
Current CPC
Class: |
F16H 57/0415
20130101 |
Class at
Publication: |
123/041.23 |
International
Class: |
F01P 9/02 20060101
F01P009/02 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 7, 2003 |
DE |
103 15 684.4 |
Claims
1-9. (canceled)
10. A transmission (8) having a transmission case (26), the
transmission comprising an area in which gear wheels (66, 68)
rotate, and a heat exchanger (30), the heat exchanger (30) absorbs
heat generated in the transmission (8), transfers the heat to a
transmission lubricant and conveys the heat to a coolant to
transport the heat away from the transmission (8), a recess (56)
through which the transmission lubricant flows and in which the
heat exchanger (30) is arranged is provided in the transmission
case (26) outside of the area in which the gear wheels (66, 68)
rotate,.
11. The transmission (8) of claim 10, wherein the heat exchanger
(30) is a separate component that can be inserted in the recess
(56) in the transmission case (26).
12. The transmission (8) of claim 10, wherein the transmission
lubricant flows through the recess (56) in the transmission case
(26) at an intake side of an oil pump (62) transporting the
transmission lubricant.
13. The transmission (8) of claim 10, wherein a bypass valve (70)
enables the heat exchanger (30) to be bypassed when the
temperatures of the transmission lubricant drops below a specified
limit, is provided at an intake side of an oil pump (62)
transporting the transmission lubricant.
14. The transmission (8) of claim 10, wherein the heat exchanger
(30) in the recess (56) is accessible from outside of the case (26)
for maintenance and assembly purposes.
15. The transmission (8) of claim 10, wherein the heat exchanger
(30) is configured as a tubular heat exchanger.
16. The transmission (8) of claim 10, wherein the coolant is
connected to a cooling unit (38) outside the transmission (8) for
the purpose of transporting away the heat from the transmission
(8).
17. The transmission (8) of claim 10, wherein the coolant used to
transport away the heat from the transmission (8) is a coolant in
the cooling system of an internal combustion engine (4) that drives
the transmission (8).
18. The transmission (8) of claim 10, wherein the coolant is a
water-based fluid and the transmission lubricant is an oil-based
fluid.
Description
[0001] This application is a national stage completion of
PCT/EP2004/003491 filed Apr. 2, 2004 which claims priority from
German Application Serial No. 103 15 684.4 filed Apr. 7, 2003.
FIELD OF THE INVENTION
[0002] The invention relates to a transmission comprising a heat
exchanger.
BACKGROUND OF THE INVENTION
[0003] In modern vehicle transmissions with high loads, the
transmission lubricant must be cooled to temperatures that are not
critical for the system. Especially in surroundings with a high
ambient temperature and for vehicles in which the transmission is
encased for noise reduction reasons, corresponding cooling devices
are provided in the form of a heat exchanger. The heat exchangers
are typically used to additionally cool the transmission lubricant,
but during the warm-up phase of the transmission they may also be
used to warm up the transmission lubricant.
[0004] The heat exchangers that are known today are either oil/air
or oil/water heat exchangers and are mounted as additional
components at a suitable location on the vehicle. Oil/water heat
exchangers may also be integrated in the engine cooling system of
the vehicle.
[0005] From DE-A-196 25 357 has become known a heat exchanger
integrated in a transmission where the heat exchanger represents
part of the transmission case. The housing walls are in part
interspersed with pipes in which oil and water circulate and the
heat from the oil is conveyed to the water. The water lines as such
are connected to the vehicle cooling unit. The transmission case
itself here represents part of the heat exchanger.
[0006] In EP-B-0 785 379 is described a transmission cooling system
comprising a heat exchanger which is arranged uncovered in the oil
sump of the transmission and conveys the heat of the ambient
transmission lubricant to the cooling water of the vehicle engine.
For this purpose, the vehicle cooling unit and the cooling lines of
the vehicle engine are connected to the heat exchanger. The
transmission cooling system comprises a transmission case, which
accommodates the gear wheels and defines an oil sump for the
transmission lubricant--the oil. At least some of the gear wheels
rotate inside the oil sump. In the oil sump of the transmission,
only the oil that is located in the direct vicinity of the heat
exchanger comes in contact with the heat exchanger and can convey
its heat. There is no forced conduction of the oil present in the
transmission past the heat exchanger for the purpose of conveying
heat to it. Such conduction is consciously foregone by eliminating
a pumping device suitable for conduction.
[0007] It is the object of the invention to design a transmission
cooling system that is more efficient.
SUMMARY OF THE INVENTION
[0008] According to the invention, a transmission has a
transmission case that comprises an area in which the gear wheels
rotate. The transmission additionally comprises a heat exchanger,
which absorbs heat generated inside the transmission and
transferred to a transmission lubricant and conveys this heat to a
coolant in order to transport the heat away from the transmission.
A recess, through which transmission lubricant flows and in which
the heat exchanger is located, is provided in the transmission case
that is located outside of the area in which the gear wheels
rotate.
[0009] Advantageously, the heat exchanger is a separate component
that can be inserted in the recess in the transmission case.
[0010] In an especially advantageous embodiment, transmission
lubricant flows through the recess in the transmission case on the
intake side of a pump transporting the transmission lubricant.
[0011] One version of the embodiment shows that a bypass valve,
which enables the heat exchanger to be bypassed when the
temperatures of the transmission lubricant drop below a specified
limit, is provided at the intake side of the pump transporting the
transmission lubricant.
[0012] For maintenance and assembly purposes, the heat exchanger in
the recess is advantageously accessible from outside of the case.
One embodiment shows the heat exchanger as a tubular heat
exchanger.
[0013] In one variation of the embodiment, the coolant is connected
to a cooling unit outside of the transmission for transporting the
heat away from the transmission. The embodiment is especially
advantageous when the coolant used to transport the heat away from
the transmission is a coolant within the cooling system of an
internal combustion engine that drives the transmission.
[0014] The coolant is preferably a water-based fluid and the
transmission lubricant an oil-based fluid.
[0015] By advantageously configuring and arranging the ducts for
the transmission lubricant, the transmission case directly forms
the housing for the heat exchanger. This results in the forced
conduction of the entire transmission lubricant across the heat
exchanger, thus improving the efficiency of the heat exchanger and
achieving a clearly smaller and more compact design. By way of
short ducts and a large cross-section of flow, which can be
implemented by way of a systematic integration in the transmission
case, a very small pressure drop is obtained. Only simple and
economic adaptation parts are required in order to conduct the oil
and to prove a seal and attachment. This guarantees a simple and
reliable design also with respect to the connection of the coolant,
without additional sealing elements.
[0016] Despite the high level of integration, a retrofitting and
removal is easily accomplished without having to disassemble the
entire transmission. The simple design and a small number of
interfaces lead to low manufacturing costs. At the same time, very
good protection of the heat exchanger from damage or other
mechanical influences is achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention will now be described, by way of example, with
reference to the accompanying drawings in which:
[0018] FIG. 1 shows a schematic illustration of a vehicle;
[0019] FIG. 2 shows a tubular heat exchanger;
[0020] FIG. 3 shows the heat exchanger of FIG. 2 in installed
condition;
[0021] FIG. 4 shows a view of the transmission case, and
[0022] FIG. 5 shows another view of the transmission case.
DETAILED DESCRIPTION OF THE INVENTION
[0023] FIG. 1 shows a schematic illustration of a vehicle 2 having
a driving motor 4, which acts upon a transmission 8 by means of a
friction clutch 6. The transmission 8 is connected via an output
shaft 10 to a differential 12, which drives a vehicle wheel 16 via
a full-floating axle 14. The friction clutch 6 is actuated by an
actuator 18, which is connected to a control unit 22 via a signal
line 20. The transmission 8 is actuated by a transmission
controller 24, which is disposed on a case 26 of the transmission
and is connected to the control unit 22 via a line 28. A heat
exchanger 30, which is connected to the engine 4 and the coolant
via two coolant lines 32 and 34, is installed in the case 26. The
heated coolant is cooled down in a vehicle cooling unit 36. A
cooling unit 38, which is mounted on the vehicle 2, can
alternatively be connected to the heat exchanger 30 via the coolant
lines 40 and 42, in which the coolant of the heat exchanger 30 is
then cooled down. The heat exchanger 30 is connected to an oil sump
64 and an oil pump 62, which transports oil to gear wheels 66, 68
in an area of the transmission case 26. At oil temperatures below a
specified limit, the transmission lubricant does not flow through
the heat exchanger 30, but is pumped through a bypass valve 70,
thus bypassing the heat exchanger 30.
[0024] FIG. 2 shows the heat exchanger 30 which, in this example,
is configured as a tubular heat exchanger. An inlet opening 44 is
connected to one coolant line 32 and an outlet opening 46 is
connected to the other coolant line 34.
[0025] FIG. 3 shows the heat exchanger 30 integrated in the
transmission case 26. The heat exchanger is simply held in place
with a flange 52, which is sealed by washers 48 and 50 and is
supported by a circlip 54. The washer 50 and flange 52 can also be
configured as one piece with the heat exchanger 30. Coolant reaches
the inside of the heat exchanger 30 via the openings 44 and 46. In
the transmission case 26, the heat exchanger 30 is arranged in a
recess 56 in such a way that the transmission lubricant drawn in by
the oil pump 62 from the oil sump 64 (FIG. 1) enters the recess 56
via an oil inlet opening 58 and can flow around the heat exchanger
30. The transmission lubricant leaves the recess 56 again force-fed
at an oil outlet opening 60 and is drawn out in the direction of
the oil pump 62.
[0026] FIG. 4 shows a section of the transmission case 26 with the
oil inlet opening 58, the oil outlet opening 60 and a fill opening
72 for the transmission lubricant. The heat exchanger 30, which is
held in place by the flange 52 and the circlip 54, is positioned in
the recess 56. The inlet opening 44 and outlet opening 46 for the
coolant are shown at the heat exchanger 30.
[0027] Finally, FIG. 5 illustrates a view into the recess 56 with
the heat exchanger removed. The recess 56 clearly shows the oil
inlet opening 58, the oil outlet opening 60 and the fill opening 72
for the transmission lubricant.
[0028] By arranging the heat exchanger 30 in a recess 56 of the
transmission case 26, through which the transmission lubricant is
force-fed guided by way of the oil pump 62, is achieved an optimal
cooling of the entire transmission lubricant.
REFERENCE NUMERALS
[0029] 2 vehicle
[0030] 4 driving motor
[0031] 6 friction clutch
[0032] 8 transmission
[0033] 10 output shaft
[0034] 12 differential
[0035] 14 full-floating axle
[0036] 16 vehicle wheel
[0037] 18 actuator
[0038] 20 signal line
[0039] 22 control unit
[0040] 24 transmission controller
[0041] 26 case
[0042] 28 line
[0043] 30 heat exchanger
[0044] 32 coolant line
[0045] 34 coolant line
[0046] 36 vehicle cooling unit
[0047] 38 cooling unit
[0048] 40 coolant line
[0049] 42 coolant line
[0050] 44 inlet opening
[0051] 46 outlet opening
[0052] 48 washer
[0053] 50 washer
[0054] 52 flange
[0055] 54 circlip
[0056] 56 recess
[0057] 58 oil inlet opening
[0058] 60 oil outlet opening
[0059] 62 oil pump
[0060] 64 oil sump
[0061] 66 gear wheel
[0062] 68 gear wheel
[0063] 70 bypass valve
[0064] 72 fill opening
* * * * *