Electronic Parking Brake Release Timing for Air Gap Control
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Solution Overview
Problem
Existing electronic parking brake apparatuses with a drum structure often terminate the parking release operation prematurely, leading to an insufficient contraction of the cylinder, which can result in a drag phenomenon due to an insufficient air gap between the drum and the shoes, especially when the operation is performed at elevated temperatures.
Innovation Solution
An electronic parking brake apparatus with a control unit that determines the end time of the cylinder's contraction operation to ensure a sufficient air gap is maintained, incorporating a motor, pair of shoes, a spring, and a control unit to adjust the contraction distance and timing based on temperature and hydraulic pressure variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the parking release operation is terminated after a preset amount of time from the no-load state, then the operation time is reduced and energy consumption is lowered, but the cylinder does not contract sufficiently to return to its original position, causing a drag phenomenon between the drum and shoes
Solution Approach 1:
The control unit monitors the contraction position of the cylinder during parking release operation and uses this feedback information to dynamically determine when to terminate the operation. Instead of using a fixed preset time, the system continuously checks whether the cylinder has contracted sufficiently to create the required air gap, and only terminates the operation when the air gap condition is satisfied, thereby preventing drag phenomenon while avoiding unnecessary extended operation time
Solution Approach 2:
The parking release operation termination criterion is changed from a static fixed time value to a dynamic condition-based determination. The control unit adjusts the operation duration based on real-time cylinder contraction status and temperature conditions, making the system adaptive to varying thermal states and ensuring sufficient air gap creation regardless of temperature variations
2Manufacturing precision
If the cylinder and shoes are required to return to their original positions at room temperature, then the air gap is sufficient at room temperature, but at elevated temperatures the drum expands outward requiring a longer contraction distance that is not achieved with fixed time operation
Solution Approach 1:
The control unit adjusts the parking release operation parameters based on detected temperature conditions. When elevated temperature is detected, the system extends the operation duration or modifies the termination criterion to account for thermal expansion of the drum, ensuring that the cylinder contracts sufficiently to create the required air gap regardless of temperature. This dynamic parameter adjustment allows the system to maintain precise air gap control across varying temperature conditions
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The control unit's precise adjustment of the contraction distance and timing prevents the drag phenomenon by ensuring a sufficient air gap is maintained between the drum and shoes, even under temperature variations, effectively addressing the premature termination issue in existing systems.
Implementation Method 1
The electronic parking brake apparatus having the drum structure changes its shape while expanding or contracting according to temperature
Data Source
AI summary
An electronic parking brake apparatus is disclosed. An embodiment of the present disclosure provides an electronic parking brake apparatus including a drum; a backing plate located on a side inside the drum; a cylinder attached to a surface of the backing plate; a motor configured to expand or contract the cylinder; a pair of shoes coupled to one side and an other side of the cylinder, respectively, with a lining attached to an outer circumferential surface thereof; a spring located between the pair of shoes and coupled to the pair of shoes; and a control unit configured to control a contraction operation of the cylinder during parking release operation, wherein the control unit determines an end time of the contraction operation.