Torque Converter

3. TORQUE CONVERTER
a. General
The section will explain the principles of the torque converter and the fundamentals of torque multiplication. Torque multiplication will be discussed first, followed by and explanation of how a torque converter works.
b. Torque Multiplication
(1) A good example of multiplying force may be found in the fulcrum and lever principle. To make the explanation of torque multiplication simpler, consider the torque converter a “floating” fulcrum. To do this it will be necessary to review the function of the fulcrum and lever to see how it applies to the torque converter.
(2) Fulcrum lever principle
(a) The fulcrum and lever principle illustrates how a force can be multiplied. In Figure 7, Diagram “A”, “x” and “y” are in balance because the fulcrum “f” is equally distant from “x” and “y”, and “x” is equal to “y”. In Diagram “B”, Figure 7, the increased load at “x” is balanced by positioning the fulcrum closer to “x” and farther from “y”.
(b) In Diagrams “C” and “D”, Figure 8, two alternate ways to lift the load at “x”, are illustrated. The force at “y” may be multiplied (Diagram C), or the distance from the fulcrum the force is applied can be increased, while reducing the force (Diagram D).
(3) Torque and speed
(a) Figure 9 illustrates one to one speed ratio at a one to one ratio at “B”. Note, that the output speed RPM at “B” will be the same as the input speed at “A”. Whatever torque or twisting effort is put into “A” will be transmitted through the output “B”. If 20 ft lbs of torque go into “A”, 20 ft lbs of torque will come out of “B”, or if there is 30 ft lbs input, there will be 30 ft lbs output, or in other words, the torque ratio is one to one ….. Suppose it becomes necessary to double the lifting force, this can be done in two ways. Increase the power source or relocate the fulcrum. The fulcrum is relocated by moving a large gear into position (Figure 10). For every two revolutions of “A”, gear “B” will make one revolution. If the input twisting effort is 20 ft lbs, the output torque will be 40 ft lbs.
(b) To make the fluid coupling perform as a torque multiplier, it is necessary only to add a reaction member, or fulcrum. The stator becomes the reaction member, by placing a stator (reaction member – Figure 15) between the load and power source, a fulcrum is provided. A torque converter has at least three elements – impeller (driving member), turbine (driven member) and stator (reaction member).