Cable-Drum Gear Arrangement for Compact Robot Joint Transmission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gear systems for changing the orientation of the axis of rotation in robotics are heavy, require large installation space, and have low rigidity, making them unsuitable for dynamic movements and are costly.
Innovation Solution
A gear arrangement using rotatable drums and cables with a drive-side and output-side configuration, allowing for torque and rotational speed transmission without twisting, and featuring a cable with a round cross-section for high rigidity and minimal installation space, utilizing grooves and tensioning devices for precise cable management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If bevel gear stages are used to change the orientation of the axis of rotation, then the gear arrangement is compact, but the weight increases and play occurs
Solution Approach 1:
The patent replaces the traditional bevel gear mechanical system with a cable-driven drum system. The cable is wound around drums arranged at different orientations, and by winding/unwinding the cable on the drums, rotational motion is transmitted while changing the axis orientation. This substitution eliminates heavy gear teeth and bearings, significantly reducing weight while maintaining compact installation space.
2Device complexity
If belt drives with trapezoidal cross-section are used to change the orientation of the axis of rotation, then the gear arrangement is simple, but the installation space increases and rigidity decreases
Solution Approach 1:
The patent changes the cable cross-section parameter from trapezoidal (traditional belt) to circular. This parameter change allows the cable to be wound around drums without requiring twisting sections, eliminating the need for large free spans and reducing the installation space. The circular cross-section maintains simplicity while achieving compact dimensions.
3Device complexity
If belt drives with trapezoidal cross-section are used to change the orientation of the axis of rotation, then the gear arrangement is simple, but the rigidity decreases
Solution Approach 1:
The patent changes the cable cross-section from trapezoidal to circular and uses high-strength cable material. The circular cross-section combined with appropriate cable tension creates a stiff, play-free connection that maintains high rigidity. The cable acts as a tension member that resists deformation, providing stable and precise motion transmission without the flexibility issues of traditional belts.
4Force
If traditional gear drives are used, then torque transmission is achieved, but play occurs and manufacturing costs increase
Solution Approach 1:
The patent replaces traditional gear drives with a cable-and-drum system where torque is transmitted through cable tension. The cable is wound around drums with precise groove profiles that prevent lateral movement and play. The groove geometry ensures the cable remains centered on the drum, eliminating backlash and providing reliable, play-free torque transmission.
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 provides a lightweight, rigid, and compact gear system that enables high-dynamic movements while reducing installation space and manufacturing costs, with cables that maintain contact and transmit rotational speed and torque efficiently.
Implementation Method 1
a cable (32, 38), which can be wound onto the at least one drive-side drum (20, 22) as well as onto the at least one output-side drum (28, 30) and has a drive-side cable end (34, 40) as well as an output-side cable end (36, 42) The cable can have a particularly high rigidity
Implementation Method 2
at least one drive-side drum (20, 22) arranged rotatably about a drive axis (18), a drive output body (24) with at least one output-side drum (28, 30) arranged rotatably about a drive output axis (26) By rotating the at least one drive-side drum about the drive axis, the rotational speed and torque can thus be transmitted to the at least one output-side drum
Data Source
AI summary
A gear arrangement (14, 14a) suitable for use in an articulated robot arm is configured with a drive body (16, 16a) with at least one drive-side drum (20, 22) arranged rotatably about a drive axis (18, 18a), and a drive output body (24, 24a) with at least one output-side drum (28, 30) arranged rotatably about a drive output axis (26, 26a). At least one cable (32, 38) is provided, and can be wound on the at least one drive-side drum (20, 22) as well as on the at least one output-side drum (28, 30), and has a drive-side cable end (34, 40) as well as an output-side cable end (36, 42). The drive-side cable end (34, 40) is arranged on the at least one drive-side drum (20, 22) and the output-side cable end (36, 42) is arranged on the at least one output-side drum (28, 30).