P4-Explore Integrated Electronic Parking Brake System

Electronic parking brake (EPB) is an electronically controlled parking brake. Through the electronic Control unit (ECU) and actuator mechanism, the driver presses a button to activate the holding mechanism, which electrically applies the brake discs to the rear wheels. Currently there are two types of mechanisms in production, the wire puller system and the caliper integrated system. EPB systems can be considered as a subset of linear control technology.

Functionality

In addition to the basic vehicle retention functions required to perform the parking brake, the EPB system provides additional functions, such as automatic release of the parking brake when the driver depresses the accelerator or slips the clutch, and re-clamping using additional force when vehicle motion is detected. In addition, the EPB can be used to implement the ramp hold function, which applies braking to prevent backsliding when the ramp is pulled away,

A new design of integrated Electric Parking Brake system, called iEPB and integrated in the brake caliper, is introduced in this paper. It consists of an electrically operated brake unit and a hydraulically pressed unit independently, and uses a special self-locking mechanism instead of a screw device to increase the efficiency and the working speed. With all conventional EPB system’s advantages, it also provides a stronger brake performance and a faster reaction time. In this paper, we describe the working principle of this new design at first, and then introduce the arrangement of the testing system, followed by a discussion of experimental data. The testing results prove the feasibility of this design. The conclusion paragraph summarizes the key points about the design of the iEPB system. INTRODUCTION The iEPB system is more convenient and safety than traditional parking systems. It’s operated and released automatically. With integrated intelligent function, the iEPB system has the following merits: • Replace a hand lever by an operation button. • Because of no hand lever, there is more space in the vehicle. • Combining a control unit, the iEPB system can be automatically operated and released at the right time, which makes the operation simpler and the driver to feel more comfortable and safer. • With high performance mechanism, the iEPB system has a faster reaction time. So we can provide the Auto-Hold function by adopting the iEPB system. There are two types of existing electric parking brake. One type is the cable puller[3], and the other is the integrated caliper[4]. This new design belongs to the integrated caliper type. Almost 100% integrated caliper type of market products use the screw device as its linear mechanism. The screw device can provide a large reduction ratio in a small space and transfer the rotation motion into linear motion with a non-reverse feature. But a low mechanical efficiency due to the screw friction makes a great energy lose. In this paper, we introduce a new design that is a type of screw free concept. Basing on the same power source, the screw free design can reduce about three-quarter reaction time of the system

SYSTEM DESCRIPTION For improving working speed, enhancing mechanism efficiency and providing a non-reverse feature at the same time, the iEPB mechanism design is the key point. The important factors that need to be considered include:

Caliper pressing force. • Working time of the actuator. • Power consumption. • Parking force that can be maintained when power off.