Rotary bearing maintenance indication

An apparatus comprising:

• a bearing for a drive shaft in a valve, the bearing including:
• a first layer including a first material having a first coefficient of friction with the drive shaft when the first material is in contact with the drive shaft;
• and
• a second layer including a second material having a second coefficient of friction with the drive shaft when the second material is in contact with the drive shaft, the second coefficient of friction greater than the first coefficient of friction, wherein the first layer and the second layer are coupled via finger joints.

An apparatus comprising:

• a valve body defining a fluid passageway;
• a flow control member in the fluid passageway;
• a drive shaft coupled to the flow control member, the drive shaft extending through a shaft bore defined in the valve body;
• a bearing around at least a portion of the drive shaft, the bearing including:
• a first layer including a first material having a first coefficient of friction with the drive shaft when the first material is in contact with the drive shaft;
• and
• a second layer including a second material having a second coefficient of friction with the drive shaft when the second material is in contact with the drive shaft, the second coefficient of friction greater than the first coefficient of friction;
• a sensor to detect a change in torque during movement of the drive shaft;
• and
• programmable circuitry to determine when the change in torque satisfies a threshold change in torque.