Rebar Tying Tool Motor Control for Faster Wire Feed and Lower Heat
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Solution Overview
Problem
Existing rebar tying tools with brushless motors face inefficiencies in lead-angle control, leading to suboptimal performance in advancing and draw-back processes due to inadequate torque and rotational speed management, resulting in prolonged operation times and increased heat generation.
Innovation Solution
Implementing a control unit that adjusts lead angles for the brushless motor in a rebar tying tool, setting a larger lead angle for the advancing process to increase rotational speed and a smaller lead angle for the draw-back process to reduce electric current and heat generation, while maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a larger lead angle is used during the advancing process to increase rotational speed, then the advancing time is shortened, but electric current consumption increases
Solution Approach 1:
The patent applies dynamics by making the lead angle adjustable and switching it between different values (first lead angle for advancing, second lead angle for draw-back) based on the operational phase. This dynamic adjustment allows the system to optimize rotational speed during advancing while controlling current consumption during draw-back, resolving the contradiction between time loss and energy use.
Solution Approach 2:
The patent changes the lead angle parameter between two distinct values depending on the process stage. During advancing, a larger first lead angle is used to maximize rotational speed and minimize time. During draw-back, a smaller second lead angle is used to reduce electric current consumption. This parameter switching strategy directly addresses the contradiction between advancing time and energy consumption.
2Loss of time
If a larger lead angle is used during the advancing process to increase rotational speed, then the advancing time is shortened, but heat generation increases
Solution Approach 1:
The patent dynamically adjusts the lead angle based on the operational phase, using a larger first lead angle during advancing to shorten time and a smaller second lead angle during draw-back to reduce heat generation. This dynamic switching resolves the contradiction between time loss and temperature increase.
Solution Approach 2:
The lead angle parameter is changed between two values depending on the process stage. The first lead angle (larger) is applied during advancing to maximize speed and minimize time. The second lead angle (smaller) is applied during draw-back to minimize heat generation. This parameter switching directly resolves the contradiction between advancing time and heat generation.
3Use of energy by moving object
If a smaller lead angle is used during the draw-back process to reduce electric current and heat generation, then the draw-back time is lengthened, but performance is maintained
Solution Approach 1:
The patent applies dynamics by switching the lead angle to a smaller second lead angle during the draw-back process, which reduces electric current consumption and heat generation. Although this increases draw-back time compared to using a larger lead angle, the overall performance is maintained because the advancing phase uses a larger first lead angle to compensate for the time difference.
Solution Approach 2:
The lead angle parameter is switched to a smaller second lead angle during draw-back to reduce energy consumption and heat generation. This parameter change accepts a longer draw-back time as a trade-off, but the overall system performance is maintained through the complementary use of a larger first lead angle during the advancing phase.
4Temperature
If a smaller lead angle is used during the draw-back process to reduce heat generation, then the draw-back time is lengthened, but performance is maintained
Solution Approach 1:
The patent dynamically switches to a smaller second lead angle during draw-back to minimize heat generation. Although this increases draw-back time, the overall performance is maintained because the advancing phase uses a larger first lead angle to compensate for the time difference, ensuring the total cycle time remains efficient.
Solution Approach 2:
The lead angle parameter is changed to a smaller second lead angle during draw-back to minimize heat generation. This parameter switching accepts a longer draw-back time as a trade-off, but the overall system performance is maintained through the complementary use of a larger first lead angle during the advancing phase.
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 shortens the advancing and draw-back times, reduces electric current consumption, and minimizes heat generation in the rebar tying tool, enhancing overall operational efficiency.
Implementation Method 1
The first brushless motor may comprise a first Hall-effect sensor, which is disposed on a first sensor board
Data Source
AI summary
A rebar tying tool includes: a feed mechanism (24), which includes a first brushless motor (32) and performs an advancing process that advances a wire (W) and a draw-back process that draws back the wire (W); a first inverter circuit (212), which is electrically connected to the first brushless motor; and a control unit (202), which controls the first brushless motor via the first inverter circuit. The first brushless motor comprises a first Hall-effect sensor (180), which is disposed on a first sensor board (178). In the advancing process, the control unit performs lead-angle control on the first brushless motor at a first lead angle. In the draw-back process, the control unit performs lead-angle control on the first brushless motor at a second lead angle. The first lead angle is set to be larger than the second lead angle.