Portable Tool Satellite Roller Screw Transmission
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Solution Overview
Problem
Existing portable electromechanical tools face limitations in transmitting significant forces with high speeds and precision while maintaining a small footprint, high rigidity, impact resistance, and long tool life, and they often require high maintenance due to hydraulic systems or have limited jaw opening amplitude.
Innovation Solution
A portable tool with a direct current electric motor powered by an accumulator battery, using a mechanical reduction gear and a satellite roller screw to transform rotational movement into longitudinal translational movement, allowing for high force transmission with precision and adaptability, eliminating hydraulic drive issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a hydraulic drive system is used, then significant force can be transmitted, but sealing problems and oil degradation occur leading to high maintenance costs
Solution Approach 1:
The patent replaces the hydraulic drive system with a mechanical drive system consisting of a ball screw mechanism. The electric motor directly drives the ball screw, which converts rotational motion to linear motion of the tool head. This eliminates hydraulic fluid, seals, and hoses, thereby eliminating sealing problems and oil degradation while maintaining the ability to transmit significant force (6-12 tons) through the mechanical advantage of the ball screw.
2Force
If a cam mechanism is used for movement transformation, then the tool can transmit force, but the movement amplitude is limited resulting in low jaw opening
Solution Approach 1:
The patent replaces the cam mechanism with a ball screw mechanism. The ball screw allows for greater linear displacement of the tool head compared to the limited movement amplitude of a cam. The threaded geometry of the ball screw enables the tool head to travel a longer distance along the axis, thereby increasing the jaw opening amplitude while still maintaining force transmission capability through the mechanical advantage of the threading.
3Force
If a ball screw is used for high force transmission, then significant force can be transmitted, but the transmission part size is large affecting portability
Solution Approach 1:
The patent segments the ball screw mechanism into compact components that can be efficiently arranged within the tool housing. The ball screw, nut, and supporting structures are designed as integrated compact units. The electric motor is positioned to directly drive the ball screw, eliminating the need for intermediate transmission elements and reducing overall transmission part size while maintaining the ability to transmit 6-12 tons of force.
4Length of moving object
If the tool head stroke is extended for better performance, then cutting capability is improved, but the tool weight increases
Solution Approach 1:
The patent uses the ball screw mechanism to achieve extended tool head stroke without proportionally increasing weight. The ball screw provides mechanical advantage, allowing a relatively compact mechanism to produce a long stroke. The direct coupling of the electric motor to the ball screw eliminates intermediate transmission components that would add weight. The design optimizes the ball screw pitch and diameter to achieve the required stroke length while minimizing the mass of the transmission components.
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
The tool achieves high force transmission with reduced weight and size, improved maneuverability, and increased precision, overcoming hydraulic drive problems like oil degradation and hose issues, while enabling efficient cutting of live underground cables safely.
Implementation Method 1
a device for transforming the rotational movement of the motor into a longitudinal translational movement which is transmitted to said working head or to a movable part thereof, characterized in that said transformation device comprises a satellite roller screw, said screw comprising a threaded part which is driven by said rotation reducer to transmit the movement via satellite rollers to a threaded nut which drives a movable part of said working head in translation
Data Source
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AI summary
Portable electromechanical tool comprising a unit (2) enclosing a continuous current electric motor (23) powered by a storage battery (4), a mechanical reduction gear (25) driven by the output shaft of said motor, which activates a working head (3) by means of a device (40) for converting the rotary motion of the motor (23) into a longitudinal translation movement, which is transmitted to said working head (3). According to the invention, said converting device (40) comprises a planetary roller screw, said screw comprising a threaded part (41), which is driven in rotation by said reduction gear to transmit motion via planetary rollers (43) to a threaded nut (42) that drives a mobile part (5) of said working head (3) in translation.