Motor Current Monitoring for Lubrication Pump Stroke Control
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Solution Overview
Problem
Lubrication systems face challenges in accurately dispensing the right amount of lubricant to prevent over- or under-lubrication, which can affect machine component service life and lead to breakdowns, requiring complex monitoring and control systems.
Innovation Solution
A lubrication system using a DC electric motor and positive displacement pump with a control unit that monitors motor current to determine discharge strokes, eliminating the need for additional equipment and simplifying control by converting motor current signals to pulses to count strokes and determine output pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional monitoring equipment (pressure switches, flow meters, volumetric meters, differential pressure switches, piston detectors) is used to accurately control lubricant dispensing, then lubrication precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the monitoring function from separate physical sensors and integrates it into the existing motor control system by analyzing motor current signals. This eliminates the need for additional monitoring equipment while maintaining lubrication precision, directly resolving the contradiction between precision and complexity.
Solution Approach 2:
The motor current signal serves multiple functions: it drives the pump motor and simultaneously provides information for monitoring discharge strokes and lubricant dispensing. This multi-functionality eliminates the need for dedicated monitoring devices, reducing device complexity while maintaining precision.
2Measurement precision
If multiple sensors and monitoring components are installed to detect lubricant flow and pump performance, then measurement accuracy is improved, but the number of components and system complexity increase
Solution Approach 1:
The motor itself serves as its own sensor by providing current signals that contain information about pump discharge strokes. This self-service approach eliminates the need for external sensors, maintaining measurement accuracy while reducing the number of components.
Solution Approach 2:
The patent changes the parameter being monitored from physical quantities requiring separate sensors (pressure, flow) to electrical parameters (motor current) that are already available in the system. This parameter change enables accurate measurement with fewer components.
3Reliability
If complex control systems with multiple sensors are used to prevent over- or under-lubrication, then lubrication reliability is improved, but ease of operation and maintenance deteriorate
Solution Approach 1:
The patent merges the control and monitoring functions into a single integrated system that uses motor current signals for both pump operation and discharge stroke detection. This consolidation improves reliability while simplifying operation and maintenance by reducing the number of independent systems that need to be managed.
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 allows for precise lubricant dispensing, reducing costs and complexity, minimizing friction and wear, optimizing machine reliability, and reducing maintenance and environmental impact.
Implementation Method 1
A lubrication system using a DC electric motor and positive displacement pump with a control unit that monitors motor current to determine discharge strokes
Implementation Method 2
a positive displacement pump driven by the motor, arranged to carry out at least one discharge stroke to dispense lubricant
Data Source
Figure 1~2
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Figure 5~6
AI summary
Lubrication system (10) comprising a motor (12), a positive displacement pump (14) driven by said motor (12), a lubricant container (16) in fluid communication with said positive displacement pump (14) and at least one lubricant outlet (18) in fluid communication with said lubricant container (16). The positive displacement pump (14) is arranged to carry out at least one discharge stroke to dispense lubricant from said at least one lubricant outlet (18) when said lubrication system (10) is in use. The lubrication system (10) also comprises a control unit (22) that is arranged to determine an amount of lubricant that is dispensed from said lubricant container (16) via said at least one lubricant outlet (18) when said lubrication system (10) is in use. The control unit (22) is namely arranged to monitor current (24) supplied to said motor (12) so as to obtain a motor current signal (26), and to determine the number of said discharge strokes from said motor current signal (26).