Harmonic Pin Ring Gear Layout for High Torque in Compact Drives
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Solution Overview
Problem
Existing gear systems face challenges in providing high power density, rigidity, and compact design while maintaining low play and allowing for versatile speed changes and directional changes, particularly in applications requiring efficient torque transmission.
Innovation Solution
The harmonic pin ring gear system features a unique configuration with two outer gears having internal toothing, a single inner gear with external toothing, and a pin ring with laterally protruding pins, utilizing a rotary transmitter to distribute radial forces effectively between the inner and outer gears, ensuring efficient torque transmission and support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a conventional single-row gear system is used, then the structure is simple, but the power density and torque transmission efficiency are insufficient
Solution Approach 1:
The patent combines two outer gears with internal toothing and a single inner gear with external toothing into a unified 2.5-row pin ring gear system. The pin ring serves as a common carrier for both gear engagements, merging multiple torque transmission paths into a single integrated structure that achieves high power density without proportionally increasing complexity
Solution Approach 2:
The patent transitions from conventional 2D gear engagement to a 3D spatial arrangement where pins extend axially from the pin ring to engage both outer gears simultaneously. This axial dimension enables the pin ring to transmit torque to multiple gears in different planes, significantly increasing power density within a compact volume
2Volume of moving object
If the gear system is made more compact, then the volume is reduced, but the rigidity and play increase
Solution Approach 1:
The patent implements asymmetric support where pins are supported in radial direction both inwards in the external toothing of the inner gear and outwards in the internal toothing of the outer gears, while the inner gear itself is supported by bearings on the housing. This localized quality distribution provides rigid constraints at critical points while maintaining compact overall dimensions
Solution Approach 2:
The patent employs curved tooth profiles with specific radii of curvature in the pin ring, inner gear, and outer gears. These curved geometries distribute contact stresses more evenly and reduce play between mating surfaces, maintaining rigidity in the compact configuration
3Adaptability or versatility
If a single inner gear is used, then the structure is simplified, but the versatility in speed changes and directional shifts is limited
Solution Approach 1:
The single inner gear with external toothing serves multiple functions: it engages with both outer gears simultaneously to provide different speed ratios, acts as a support structure for pin radial loading, and can be configured to enable directional reversals. This multi-functionality achieves versatility without requiring multiple separate gears
Solution Approach 2:
The patent enables dynamic configuration where the pin ring can be selectively engaged or disengaged from either or both outer gears through the rotary transmitter mechanism. This dynamic capability allows the system to switch between different gear ratios and rotational directions using the same single inner gear structure
Data Source
AI summary
A harmonic ring gear system can include at least one inner gear with external toothing, the at least one inner gear defining an axis of rotation; at least one outer gear with internal toothing arranged concentrically to the at least one inner gear about the axis of rotation, the internal toothing spaced apart from the external toothing; a pin ring positioned between the at least one inner gear and the at least one outer gear, the pin ring comprising a multiplicity of pins; and a rotary transmitter configured to lift a portion of the pins of the multiplicity of pins off the external toothing and press the portion of the pins into the internal toothing.