Servo Assembly with Harmonic Drive for Robot Miniaturization
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Solution Overview
Problem
Conventional servos are large in size, which hinders the miniaturization of robots due to their configuration, where the motor is arranged within the servo housing with its output shaft engaged through a spline and gear, leading to bulkiness.
Innovation Solution
A compact servo design incorporating a harmonic drive system with a flex spline and circular spline, where the wave generator causes elastic deformation of the flex spline, allowing for high-speed rotation and low-speed power output, along with a crossed roller bearing for high-precision rotary motion and a compact motor assembly, enabling reduced size and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the motor is arranged within the servo housing with output shaft engaged through spline and gear, then the motor can be integrated into the servo structure, but the servo becomes large and bulky
Solution Approach 1:
The patent extracts the traditional spline and gear transmission components from the servo structure, replacing them with a direct-drive configuration where the motor output shaft directly drives the load without intermediate transmission elements, thereby reducing the servo housing area while maintaining integration
Solution Approach 2:
The patent merges the motor assembly with the servo housing into a more compact integrated unit, eliminating the need for separate spline and gear components, which reduces overall device complexity and footprint
2Power
If traditional spline and gear transmission is used, then power transmission is achieved, but the servo size increases and miniaturization is hindered
Solution Approach 1:
The patent removes the spline and gear transmission components that occupy significant volume, replacing them with a direct-drive configuration that maintains power transmission capability while dramatically reducing the servo volume to enable miniaturization
Solution Approach 2:
The patent replaces the mechanical spline and gear transmission system with a direct mechanical coupling system, eliminating intermediate transmission stages and reducing the overall volume required for power 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 compact servo design facilitates the miniaturization and lightweightness of robots, enhancing their structural compactness and efficiency while maintaining high-precision rotary motion.
Implementation Method 1
the wave generator causes elastic deformation of the flex spline, allowing for high-speed rotation and low-speed power output
Implementation Method 2
a crossed roller bearing for high-precision rotary motion
Data Source
AI summary
A servo includes a casing, a motor assembly arranged within the casing and including a hollow output shaft, a harmonic drive including a flex spline, a wave generator arranged and a circular spline that comprises, a first bearing to rotatably connect the flex spline to the circular spline so as to enable one of the flex spline and the circular spline to serve as an output member, and enable the other one to serve as a fixed member, a post fixed to the output member and received in the output shaft, a first source member arranged at one end of the post that is away from the output member; and a control circuit board having a first sensing member. The first sensing member and the first source member corporately constitute a rotation sensor to detect rotation of the output member.