Spatial Skew Gear Gripper for Stable Force Control
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Solution Overview
Problem
Existing gripping devices face challenges in achieving low mass, simple assembly, stable, safe, and energy-saving movement of carriages carrying gripping elements, with limitations in position control and energy efficiency.
Innovation Solution
A gripping device featuring a three-dimensional helical gear with a helical toothed worm gear and a fake worm wheel arranged on a common shaft, utilizing a self-locking worm gear for stable gripping force without continuous control deflections, and employing a synchronous gear wheel with a helical spur gear-like worm wheel for efficient displacement and force control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional spur gear or flat gear is used to drive the carriages, then the assembly is simple, but the gripping force cannot be maintained without continuous control deflections that cause overheating
Solution Approach 1:
The worm gear mechanism provides self-locking capability, allowing the gripping force to be maintained automatically without continuous energy input from the motor. The self-locking property of the worm gear prevents back-driving, so the load itself maintains the gripping position without requiring active control or additional energy consumption.
Solution Approach 2:
The patent converts the inherent friction in the worm gear, which would normally be considered a loss, into a beneficial self-locking mechanism. The friction that causes energy loss in conventional gears is utilized here to prevent reverse motion and maintain gripping force automatically, turning a harmful effect into a useful feature.
2Reliability
If a worm gear with fake worm wheel is used, then the gripping force is maintained stably, but the device complexity increases
Solution Approach 1:
The gear system is divided into functionally distinct components: a standard spur gear for driving motion and a worm gear with fake worm wheel for self-locking and force multiplication. This segmentation allows each component to be optimized for its specific function while maintaining overall system manageability and assembly simplicity.
Solution Approach 2:
The patent introduces a three-dimensional helical gear configuration with the worm gear arranged in a different spatial dimension relative to the spur gear. This dimensional arrangement allows the two gear types to mesh effectively while maintaining a compact structure, reducing the complexity impact of combining different gear mechanisms.
3Reliability
If continuous control deflections are applied to maintain gripping force, then the gripping is stable, but the drive overheats
Solution Approach 1:
Instead of continuous control deflections, the system uses periodic intermittent control where the motor only needs to apply torque during gripping and positioning phases. The self-locking worm gear maintains the gripping force during holding phases without requiring continuous motor activation, allowing the drive to cool down during idle periods and reducing overall temperature buildup.
Solution Approach 2:
The worm gear mechanism serves itself to maintain gripping force through its self-locking property, eliminating the need for continuous active control from the motor. This passive maintenance mechanism prevents the drive from overheating by removing the requirement for continuous energy input and associated heat generation.
4Ease of manufacture
If individual pneumatic cylinders are used to drive each carriage, then the assembly is simple, but position control is not possible
Solution Approach 1:
The single electric motor with worm gear mechanism serves multiple functions: it provides both the driving force for moving the carriages and the position control capability through the self-locking mechanism. This multi-functional design achieves both the simplicity of a single drive source and the precision of controlled positioning, eliminating the need for separate pneumatic cylinders while enabling position control.
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 solution enables energy-saving and stable movement of gripping elements with maintained gripping force, reducing the need for continuous control and minimizing drive overheating, while allowing for precise handling of workpieces through displacement and force control.
Implementation Method 1
Since the last gear stage in this device before driving the carriage is a self-locking worm gear, the gripping force is maintained without the need for permanent control deflections that overheat the drive.
Implementation Method 2
the three-dimensional helical gear is a worm gear having a helical toothed, fake worm wheel, the worm wheel being arranged with the synchronous gear wheel on a common shaft
Data Source
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AI summary
The gripper has two parts arranged in a housing (10) with two slip parts (121, 122). Each slip part is interlocked (127) with the gripping element and arranged in a housing (10) being synchronous to gear teeth (131). The synchronous gear is on a spatial screw gear (80) and a flat wheel is provided with an electric motor (61).