SECTION 7B HYDRAULIC TORQUE CONVERTER
Page 4
TD-25M EXTRA DRESSTA
GENERAL
Legend for Fig.’s 7B.1 and 7B.2
1. Converter Housing
2. Ground Sleeve Hub
3. Seal Ring
4. Roller Bearing
5. Drive Gear
6. Retaining Ring
7. Spacer Washer
8. Ball Bearing
9. Retaining Ring
10. Ball Bearing
11. Driven Gear
12. Impeller
13. Thrust Washer
13A. Bolt
14. Output Shaft
15. Seal Ring
16. Retaining Ring
17. Spacer Washer
18. Ball/Single Row
Bearing
19. Shims
20. O-Ring
21. Seal Ring
22. Rear Cover
22A. Bolt
22B. Washer
23. Output Flange
24. O-Ring
25. Thrust Washer
25A. Bolt
26. Stator
27. Retaining Ring
28. Retaining Ring
29. Turbine Assy
30. Drive Housing
30A. Bolt
30B. Washer
31. Ball/Single Row
Bearing
32. Shims
33. Thrust Washer
33A. Bolt
34. Shims
35. Housing Cover
35A. Bolt
35B. Washer
36. Gear Ring
A – TC Oil Outlet
B – TC Oil Inlet
This machine is equipped with a single stage, single phase torque converter, bolted directly to the
engine flywheel housing. The torque converter automatically varies the output required at the
tracks to meet the changing load requirements of the machine. Engine power is transferred by the
converter with little change in torque when the load is light. When a heavy load is encountered, the
torque multiplication becomes greater, but with a resulting loss of machine speed. It is important to
note that the converter does not increase engine horsepower, but does increase the amount of
torque available at the tracks.
Converter housing (1) is flange-mounted to the machine engine. Engine power is
transferred through drive housing (30) driven by the engine flywheel. Impeller (12) bolted to drive
housing (30) drives drive gear (5), which, in turn, drives gear pumps through driven gears (11) that
supply oil both to machine drive train and its hydraulic equipment. Turbine assy (29) is splined to
the output shaft (14) on one hand and there is the output flange (23) splined to the output shaft
(14) on the other hand. The stator (26) is mounted between the impeller and turbine assy splined
to the stationary ground sleeve hub (2). There is no direct mechanical connection between the
impeller and turbine or stator.
Operating engine turns bladed impeller (12) bolted to drive housing (30). At the same time
external gear pump is powered from the engine and supplies oil to impeller blades. The impeller
draws fluid from the opening surrounding the hub and ejects it from its blades at high velocity. The
turbine (29) is positioned opposite the impeller and its blades receive the full impact of this velocity.
Oil exits from the turbine in the opposite direction of rotation from that of the impeller. The turbine
divides the oil flow between converter discharge passage as one oil stream, while the other oil
stream impacts stator (26) blades, giving a surplus torque charging the turbine (29). The curved
blades of the stator (26) re-directs the flow back to the impeller in the same direction as the
impeller is moving, completing the cycle. This constant gain in energy of impeller flow oil and stator
reaction torque increase the energy received by the turbine with the result of torque multiplication
at output shaft (14) and output flange (23) of the torque converter.
Torque multiplication is determined by the speed of the turbine in relation to the impeller.
A ball thrown at a paddle will strike it with more force if the paddle is stationary than it will if the
paddle is moving in the same direction as the ball. Similarly, when the turbine (29) is rotating as
fast as the impeller (12), the oil passes easily through the turbine applying little or no force to the
blades. As the output shaft slows down, the fluid strikes the turbine blades with more force. The
maximum striking force of the fluid is reached when the turbine is stopped. This occurs in the
machine when the output shaft is stalled by a heavy load.
Seal rings (3) and (15) at oil inlet and outlet, respectively separate oil high pressure
chamber from the other torque converter work volume. These seal rings and their condition are
crucial to torque converter leakage rate and consequently, torque converter loss rate and its
efficiency.
To Next Page
Loading...