Method of testing friction components for automatic transmissions

A method of testing a friction component for an automatic transmission, comprising:

• installing the friction component having first and second parts in a test stand having a drive shaft and a grounding element with the first part of the friction component attached to the drive shaft and the second part of the friction component attached to the grounding element;
• rotating the first part of the friction component with a motor drive until the drive shaft and first part of the friction component rotate at a target sliding speed (Vtarget) and continuing rotation at Vtarget;
• applying an actuation force to an actuator of the friction component at a time (t0);
• continuing operation of the motor drive to maintain the speed of rotation of the drive shaft at Vtarget for a period of time until a predetermined level of torque (Tth) is obtained, wherein upon obtaining Tth the motor torque is reduced to a predetermined level (Tm), upon reduction to Tm the sliding speed of the drive shaft decreases, and terminating the test when the sliding speed falls to zero during a time period referred to as an inertia phase (ti).

A system for testing a friction component for an automatic transmission, comprising:

• a test stand having a drive shaft and a grounding portion;
• a friction component installed in the test stand, the friction component having a first part attached to the drive shaft and a second part attached to the grounding portion;
• a motor drive rotating the drive shaft of the test stand until the first part of the friction component and the drive shaft rotate at a target sliding speed (Vtarget) and continuing rotation at Vtarget;
• an actuator of the friction component being actuated at a time (t0) and the actuator having a return mechanism that applies a biasing force to return the friction component to a disengaged condition, causing the friction component to be stroked against the return mechanism during a time (ts) to apply an engagement force at a time t0+ts;
• and
• wherein operation of the motor drive is continued to maintain the speed of rotation of the drive shaft at Vtarget for a period of time corresponding to a target torque phase time (tt), and decoupling the motor drive from the drive shaft at the end of tt allowing the rotating speed of the drive shaft and first part of the friction component to decrease in response to engagement of the friction component, and terminating the test when the sliding speed falls to zero during a time period referred to as an inertia phase (ti).