Electric Brake Actuator Lock Control for Reliable Reverse-Input Release
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Solution Overview
Problem
Existing electric-powered actuators for vehicles face challenges in reliably transitioning to and from a reverse-input holding state, leading to issues like unintended vehicle movement on inclines and increased costs due to complex structures and varying holding loads.
Innovation Solution
An electric-powered actuator with a control device that includes a motor angle estimation unit and a reverse-input holding control section, which synchronously moves an engaging part with the rotor, allowing engagement and disengagement control without motor torque, using a solenoid drive source and intermediate control to maintain a predetermined positional relation between engaging and engaged parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an engaging part with an inclined portion (ratchet) is used to release engagement, then the reverse-input holding state can be released, but the dimension of the engaging part increases and holding load varies
Solution Approach 1:
The patent removes the inclined portion (ratchet) from the engaging part, extracting the problematic element that caused increased dimension and holding load variation. Instead, a separate solenoid-based lock mechanism is introduced to handle the release function, allowing the engaging part to maintain a compact, simple structure while still achieving reliable state transition.
Solution Approach 2:
The patent introduces a solenoid as an intermediary element between the engaging part and the release mechanism. The solenoid acts as a mediator that enables controlled release of the engagement without requiring structural modifications to the engaging part itself, thus maintaining dimensional compactness while achieving reliable release functionality.
2Reliability
If an inclined portion is used to release engagement, then the engagement can be released, but the structure becomes complicated and processing cost increases
Solution Approach 1:
The patent extracts the inclined portion (ratchet) from the engaging part structure, eliminating the need for complex machining operations required to create inclined surfaces. This simplification directly reduces processing costs and manufacturing complexity while maintaining the ability to release engagement through the alternative solenoid-based mechanism.
Solution Approach 2:
The patent replaces the mechanical inclined portion (ratchet) system with an electromechanical solenoid system. This substitution eliminates the need for complex mechanical geometry (inclined surfaces) and replaces it with a simpler electromagnetic actuation mechanism, thereby reducing manufacturing complexity and processing costs.
3Reliability
If an inclined portion is used to release engagement, then engagement can be released, but friction coefficient and control angle must be precisely controlled increasing quality control costs
Solution Approach 1:
The patent removes the inclined portion that required precise control of friction coefficient and control angle. By eliminating this element, the patent eliminates the associated quality control requirements and manufacturing precision demands, while still achieving reliable engagement release through the solenoid-based lock mechanism.
Solution Approach 2:
The patent replaces the friction-based inclined portion mechanism with an electromechanical solenoid system. This substitution eliminates the need for precise control of friction coefficients and control angles, as the solenoid provides controlled actuation through electromagnetic force, thereby reducing quality control costs and manufacturing precision requirements.
4Use of energy by moving object
If a reverse-input holding mechanism is used without motor torque, then power consumption is reduced, but reliable transition to and from holding state becomes difficult
Solution Approach 1:
The patent applies preliminary action by using the motor to position the engaging part and engaged part in a predetermined positional relation before the solenoid actuates the lock mechanism. This preliminary positioning ensures that when the solenoid releases the lock, the parts are already in the correct positions for reliable engagement or disengagement, thereby enabling reliable state transitions without continuous motor torque during the holding state.
Solution Approach 2:
The patent employs feedback control to monitor the positions of the engaging part and engaged part, and adjusts the motor operation to maintain a predetermined positional relation between them. This feedback mechanism ensures that the parts are properly positioned before and during the state transition, enabling reliable operation of the reverse-input holding mechanism while minimizing power consumption during the holding state.
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
This solution enables reliable operation of the reverse-input holding mechanism, reducing costs and improving reliability by accurately controlling the engagement and disengagement states, thus preventing unintended vehicle movement and simplifying the structure.
Implementation Method 1
a lock mechanism Ks including a drive source 16 configured to drive an engaging part 15
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
Provided are an electric-powered actuator and an electric braking device which are capable of reliably operating a reverse-input holding mechanism and can achieve cost savings. The electric-powered actuator includes a control device (2) including: a motor angle estimation unit (22a), and a reverse-input holding control section (24) having a function of engaging an engaging part (15) with an engaged part by controlling a solenoid (16) to set the reverse-input holding mechanism (7) into a reverse-input holding state while the electric-powered actuator (DA) is applying a load and a function of, from the reverse-input holding state, disengaging the engaging part (15) from the engaged part to set the reverse-input holding mechanism (7) into a reverse-input holding release state. The reverse-input holding control section (24) includes an engagement intermediate control function section (24a) configured to control the estimated rotation angle such that the engaged part and the engaging part (15) come into a predetermined positional relation within a certain period of time, when the engaging part (15) is brought into engagement with the engaged part and when the engaging part (15) is brought out of engagement with the engaged part.