Electric Work Machine Dual Braking for Kickback Control
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Solution Overview
Problem
Electric work machines face challenges in quickly stopping the rotor to prevent injury or damage during kickback while minimizing user recoil, as existing braking methods either stop the rotor too abruptly or not quickly enough.
Innovation Solution
The implementation of a dual braking control system in electric work machines, which includes a kickback-detection mechanism that generates a strong braking force to immediately stop the rotor during kickback and a weaker braking force when the user releases the trigger, allowing for controlled deceleration and reduced recoil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a strong braking force is applied to stop the rotor quickly during kickback, then the time to stop rotation is reduced, but the recoil felt by the user increases
Solution Approach 1:
The braking force is made dynamic by switching between two distinct braking modes (first braking control and second braking control) based on the detected condition. During kickback, strong braking is applied; during normal operation, weaker braking is applied. This dynamic adjustment resolves the contradiction by adapting the braking intensity to the specific operational context.
Solution Approach 2:
The braking parameter (braking force magnitude) is changed based on the operational state. The control part switches between a first braking control with stronger braking force and a second braking control with weaker braking force. This parameter change allows the system to achieve quick stopping when needed while minimizing recoil during normal operation.
2Speed
If braking is applied to the motor, then the rotation of the cutting tool can be stopped faster, but a stronger recoil may be felt by the user
Solution Approach 1:
The braking system dynamically adjusts its characteristics based on the operational state. During kickback events, the first braking control provides rapid deceleration; during normal trigger release, the second braking control provides gentler deceleration. This dynamic behavior resolves the contradiction between stopping speed and recoil generation.
Solution Approach 2:
The kickback-detection part provides feedback about the operational state to the control part, which then selects the appropriate braking control mode. This feedback mechanism enables the system to respond appropriately to kickback events while avoiding unnecessary strong braking during normal operation, thus resolving the contradiction.
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 approach effectively shortens the time to stop the rotor during kickback while minimizing user recoil, enhancing safety and reducing the risk of injury or damage.
Implementation Method 1
a motor (e.g., an electric motor, such as a brushless motor)
Implementation Method 2
The control part is configured to perform a first braking control... The first braking control causes the motor to generate a first braking force to immediately (abruptly) stop rotation of the rotor of the motor
Data Source
AI summary
An electric work machine (1) includes a motor (1), a manipulatable part (9), a control part (20) configured to perform a first braking control and a second braking control that differ from each other, and a kickback-detection part (20, S30) that detects whether kickback has occurred. The control part energizes the motor in response to detection of user-manipulation of the manipulatable part. In response to detection of kickback, the control part performs the first braking control and thereby causes the motor to generate a first braking force. In response to detection of a state change of the manipulatable part to an unmanipulated or OFF state, the control part performs the second braking control and thereby causes the motor to generate a second braking force, which is weaker than the first braking force.