Multi-Speed Press Ram Drive Using Dual Motors and Clutching
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Solution Overview
Problem
Large press machines face challenges in delivering both high-speed and high-torque conditions necessary for forming parts efficiently, as conventional motors struggle to meet these demands simultaneously, leading to compromised productivity and issues with hydraulic actuators such as temperature dependency and messiness.
Innovation Solution
A linear-actuated press machine is designed with a moveable press ram, an actuator, and two motors. The actuator includes dual male-female thread mechanisms for producing high-force and high-speed linear movements. The first motor drives the first thread mechanism for high-force conditions, while the second motor drives the second thread mechanism for high-speed conditions, allowing for efficient part formation without the drawbacks of hydraulic systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a motor is chosen to deliver high torque for forming parts, then the force capability is improved, but the rotational speed and vertical speed of the moving tool are limited
Solution Approach 1:
The patent divides the drive system into two separate motors: a high-torque motor for delivering forming force and a high-speed motor for advancing and retracting the tool. This segmentation allows each motor to be optimized for its specific function without compromise, resolving the contradiction between force capability and speed.
Solution Approach 2:
The high-speed motor serves multiple functions: advancing the tool to the workpiece, retracting the tool after forming, and potentially assisting during forming. This multi-functionality allows the system to achieve high speeds for non-forming operations while the high-torque motor handles force-intensive operations.
2Force
If hydraulic actuators are used to deliver high forces with acceptable speed, then the force and speed requirements are met, but temperature dependency and fluid leakage problems occur
Solution Approach 1:
The patent replaces the hydraulic actuation system with a dual motor-driven screw mechanism. This mechanical substitution eliminates the need for hydraulic fluid, pumps, valves, and filters, thereby eliminating temperature dependency and fluid leakage problems while maintaining the ability to deliver high forces through the high-torque motor.
3Force
If crankshafts are used to drive large presses, then high forces can be delivered, but complex bearing systems with tight tolerances and lubrication requirements are required
Solution Approach 1:
The patent replaces the crankshaft mechanism with a linear motor-driven screw mechanism. This substitution eliminates the need for complex bearing systems, tight tolerances, and lubrication systems associated with crankshafts, while still achieving high force delivery through the high-torque motor and screw mechanism.
4Device complexity
If a single motor is used to drive the press, then the system is simpler, but both high-speed and high-torque conditions cannot be delivered simultaneously
Solution Approach 1:
The patent segments the drive function into two specialized motors, which increases system complexity but enables both high-speed and high-torque conditions to be delivered when needed. The high-speed motor handles rapid advancement and retraction, while the high-torque motor handles force-intensive forming operations, thereby achieving high productivity.
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 the press machine to deliver high forces comparable to hydraulic presses while maintaining controllability and high speeds, thereby increasing productivity and avoiding the problems associated with hydraulic and crankshaft-driven presses.
Implementation Method 1
The actuator includes a first male-female thread mechanism for producing a first linear movement of the moveable press ram and a second male-female thread mechanism for producing a second linear movement of the movable press ram
Data Source
AI summary
A press machine comprises a moveable press ram, an actuator, a first motor system, a second motor system, and a belt system. The moveable press ram holds a tool that forms a part. The actuator linearly moves the moveable press ram by use of a male-female thread mechanism. The actuator includes an actuator sprocket coupled to the male-female thread mechanism. The first motor system produces a high-force linear movement condition to the press ram, and includes a clutch coupled to a first motor and a first motor sprocket coupled to the clutch. The second motor system produces a high-speed linear movement condition to the press ram. The belt system couples the actuator sprocket, the first motor sprocket, and the second motor sprocket. The clutch allows the first motor to partially or fully disengage from rotational movement of the first sprocket when the belt is being driven by the second motor.