[0001 ] HEAT EXCHANGER WITH INTEGRATED BYPASS VAIVE
[0002]
[0003]
[0004] The present invention relates to a heat exchanger and a transmission
with a heat exchanger according to the type described in more detail in the
preamble of claim 1.
[0005]
[0006] In modern vehicle transmissions subject to high ioads, the trau:;niis!;r u
lubricant has to be cooled to temperatures that are uncritical for the system, In particular, in surroundings with high ambient temperatures and for vehicle;. in which the transmission is encapsulated for noise reduction reasons, cooiinu devices are accordingly provided in the form of heat exchangers, exchangers are normally used for additional cooling of the transmission lubricant, but may also be used ioi wanning up the
[0007] The currently known heat exchangers are either oil/air or oil/water
exchangers and are mounted as additional components at a suitable location in the vehicle. Oil/water heat exchangers may also be integrated in the engine cooling system of the vehicle.
[0008] DE 103 15 684 A1 disclose.'; a transmission having a transmission
housing, which comprises a region, in which the gear wheels transmission also has a heat exchanger which absorbs the heat the transmission and transferred to the transmission lubricant and

absorbs the heat generated in the transmission and transtesed 10 the
transmission lubricant and release to a coolant for transportation of

heat away from the transmission A process is provided in the transmission housing that is arranged outside of the region in which the gear whole through which the transmission lubricant flows and in which the exchanger is arranged.


of the heat exchanger, achieving a smaller and more compact design. I 'y way



[0026]

(0026) The basic principle of the present invention which allows various
embodiments is explained below in more detail by way of example with
reference to a drawing. The drawing slows:
[0027] FIG. 1 is a schematic illustration of a vehicle with a prior
exchanger and bypass valve;
|0028] FIG. 2 is an embodiment of a heat exchanger with an integrated bypass
valve during transmission lubricant cooling; and
[0029] FIG. 3 is the heat exchanger according to FIG. 2 during a bypass
function.



[0034] The heat exchanger 30 has a bypass valve 48 that is arranged at the
heat exchanger which enables the heat exchanger 30 to be bypassed at a predefined low pressure.


heat exchanger 30 that is arranged in (he recess 56 Hydraulid line 74, convey the transmission lubricant from the oil sump 64, via the bypass

48, through the area limited by the sealing element 72 and the bypass ducts; 76 to the oil pump 62 and/or to the gear wlieels 66, 68.

Reference numerals
2 Vehicle 4 Drive motor 6 Friction clutch 8 Transmission 10 Output shaft 12 Differential 14 Half axle 16 Vehicle wheel 18 Actuator 20 Signal line 22 Control unit 24 Transmission controller 26 Housing 28 Line
30 Heat exchanger 32 Coolant line 34 Coolant line 36 Vehicle cooling unit 38 Cooling unit 40 Coolant line 42 Coolant line 44 Inlet opening 46 Outlet opening 48 Integrated bypass valve

50 Valve cover spring 52 Valve cover 54 Valve seat 56 Recess 58 Oil inlet opening 62 Oil pump 64 Oil sump 66 Gearwheel 68 Gearwheel 70 Bypass valve 72 Sealing element 74 Hydraulic lines 76 Bypass ducts

CLAIMS
1. A transmission (8) having a transmission housing (26) which
provided with a region in which gear wheels (66, 68) rotate and a
exchanger (30) which absorbs the heat generated in the transmission
transferred to a transmission lubricant and releases it to a coolant is transportation
the heat away from the transmission (0), characterized in that the heat
exchanger (30) comprises an integrated bypass valve (48) which enable the
heat exchanger (30) to be bypassed starting at a predefined low and/or
excess pressure.
2. Transmission (8) according to claim 1, characterized in that a
recess (56) is provided through which the transmission lubricant flows and is
which the heat exchanger (30) is arranged in the transmission housing us;
outside of the region in which the gear wheels (66, 68) rotate.
3. Transmission (8) according lo any one of claims 1 or 2, characterized in that the bypass valve (48) is configured as a poppei. valve-comprising a valve cover (52) and a valve cover spring (50).
4. Transmission (8) according U> any one of claims 1 to 3, characterized
in that the transmission housing (26) exhibits a valve seat (54) on which the valve cover (52) of the bypass valve (48) abuts in the inactive slate
5. Transmission (8) according to any one of claims 1 to 4,
characterized
in that the function of the heal, exchanger (30) and the bypass are separated from one another by a sealing element (72).
6. Transmission (8) according to claim 5, characterized in that the
sealing element (72) is configured as a plastic or metal duct.
7. Transmission (8) according to any one of claims 1 to 6,
characterized in that the bypass ducts (7V)) required for the bypass

are integrated directly in the transmission housing (26),
8. Transmission (8) according to any one of the preceding claims characterized in that the valve cover spring (50) is designed in such that the valve cover (52) opens starting at a predefined low and/or
pressure, thus releasing the connection to the bypass ducts (?6),