Sewing Machine Common Driver Circuit Reducing CPU Ports
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Solution Overview
Problem
Recent sewing machines require a large number of driver circuits and input/output ports in the CPU to manage multiple stepping motors for various functions, leading to increased costs and machine size, as well as the need for different drive currents due to varying torque requirements for different driving mechanisms.
Innovation Solution
A sewing machine design that uses a CPU with a reduced number of input/output ports, featuring a switching unit and voltage regulating circuit to selectively activate and provide appropriate drive currents to electric actuators connected to common ports, and a common driver circuit with a control pulse signal generator to adjust the duty ratio of control signals for appropriate drive current output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple driver circuits and input/output ports are used to manage multiple stepping motors, then the sewing machine can drive more driving mechanisms, but the cost and machine size increase
Solution Approach 1:
The patent applies universality by designing a single driver circuit that can drive multiple stepping motors with different torque requirements. The driver circuit is configured to selectively connect to different stepping motors based on operation type, allowing one circuit to perform multiple functions that previously required separate circuits for each motor.
Solution Approach 2:
The patent merges multiple driver circuits into a single unified driver circuit that handles multiple stepping motors. By combining the driving functions and using a common control interface, the system reduces the total number of driver circuits and input/output ports while maintaining the ability to drive all necessary motors.
2Reliability
If different drive currents are supplied to stepping motors for different torque requirements, then each motor operates optimally, but more driver circuits are needed
Solution Approach 1:
The patent applies parameter changes by enabling the single driver circuit to vary its drive current output based on which stepping motor is being driven and the operation type. The circuit can supply different current levels (e.g., higher current for needle bar swinging, lower current for feed dog movement) by changing its operating parameters in response to control signals.
Solution Approach 2:
The driver circuit is designed to be dynamic, selectively connecting to different stepping motors and adjusting drive current levels based on real-time operation requirements. The circuit transitions between different driving states depending on the selected operation type, allowing optimal current delivery to each motor without requiring dedicated circuits.
3Adaptability or versatility
If a CPU with more input/output ports is used, then more stepping motors can be controlled directly, but the CPU cost and size increase
Solution Approach 1:
The patent applies universality by designing the CPU interface to handle multiple operation types through a reduced set of input/output ports. The same ports are reused for different motors depending on the selected operation, allowing the CPU to control more motors than the number of physical ports would suggest.
Solution Approach 2:
The patent merges the control functions for multiple motors into a unified control interface. By combining the control signals for different motors through the same CPU ports and using operation-type-based selection, the system reduces the total number of CPU input/output ports required while maintaining full control capability.
Data Source
AI summary
A feed dog drive motor and an X-direction motor are connected to common input/output ports of a CPU via first and second driver IC circuits, respectively. In response to a drive switching signal generated from the CPU, selected one of the first and second driver IC circuits is enabled, causing the feed dog drive motor and the X-directional motor to selectively energize. A common driver IC circuit can be used in place of the first and second driver IC circuits. With such a configuration, the number of input/output ports of the CPU as well as the number of driver IC circuits can be reduced.