The scope of this new recommended practice should include, but not necessarily be limited to:
1. Define vehicle operating conditions used to drive MOC-EPB actuator design and selection
2. Define brake corner operating conditions (e.g. temperature and state of burnish) used to drive MOC-EPB actuator design and selection
3. Define actuator operating conditions (e.g. temperature, voltage, current limit, and state of wear) used to drive MOC-EPB actuator design and selection
4. Define methodology for addressing part to part variation in performance
Rationale: A number of MOC-EPB actuator configurations are available, and a series of calculations are generally performed to select the right actuator for a new vehicle application (or to develop a new actuator for a new or existing vehicle application). The basic calculation determines the clamp force required to park the vehicle on a specified grade with a specified condition (usually described by temperature) of the brake, and then selects an actuator (or specifies a clamp load for a new actuator) needed to provide this clamp load under specified operating conditions of the actuator.
Factors considered in this calculation generally include, but are not limited to:
• Vehicle mass
• Grade of surface parking requirement applies to
• Operating conditions of brake that requirements apply to (temperature, state of burnish/wear)
• Operating conditions of actuator (temperature, voltage, current limit, state of wear)
The hypothesis of the committee in creating this proposal is that there are many slightly different methodologies in use in the industry, with no real competitive advantage for maintaining these differences.
