Reciprocating Engine Planetary Gear Support Rigidity
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Solution Overview
Problem
Existing reciprocating internal combustion engines face challenges in ensuring overall support strength and rigidity due to the cantilevered support of the planetary gear mechanism, which affects the transmission of forces from the piston.
Innovation Solution
The engine incorporates a planetary gear mechanism with a ring gear, a carrier, and a planetary gear, along with a crank member and a piston member, where the planetary gear is rotatably supported by the carrier and the ring gear, and the crank member is coupled to the planetary gear. This configuration includes planetary bearings and carrier bearings for enhanced support and includes a transmission mechanism to transmit the carrier's rotation to an output member.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the planetary gear is supported in a cantilever manner on the crank arm, then the device complexity is reduced, but the support strength and rigidity deteriorate
Solution Approach 1:
The planetary gear support structure is segmented into multiple bearing points: planetary bearings disposed on both sides of the planetary gear in the axial direction, and carrier bearings disposed on both sides of the ring gear in the axial direction. This segmentation provides distributed support that enhances rigidity while maintaining structural manageability
Solution Approach 2:
The support system transitions from a single-plane cantilever support to a three-dimensional distributed bearing arrangement. Bearings are positioned at multiple locations in the axial direction, creating a spatial support network that significantly improves structural rigidity and load distribution
2Ease of manufacture
If the planetary gear is supported in a cantilever manner, then the ease of manufacture is improved, but the reliability deteriorates
Solution Approach 1:
The support function is segmented across multiple bearing components positioned at different locations, distributing mechanical stresses and improving reliability without substantially complicating the manufacturing process
Solution Approach 2:
High-strength bearing support is applied locally at critical positions (both sides of the planetary gear and both sides of the ring gear in the axial direction), providing enhanced reliability precisely where mechanical loads are most severe
Data Source
AI summary
A reciprocating internal combustion engine including a planetary gear mechanism including a ring gear, a carrier rotatably supported with respect to the ring gear, and a planetary gear rotatably supported with respect to the carrier and meshes with the ring gear; a crank member coupled to rotate integrally with the planetary gear; a piston member coupled to the crank member to be relatively rotatable about an input axis set separately from the planetary axis; and a transmission mechanism transmitting a rotation of the carrier to an output member. The crank member includes a pair of crank portions disposed separately on both sides of the carrier in the axial direction, the piston member includes a piston body and a pair of coupling portions disposed separately on both sides of the carrier axially, the first crank portion and the second crank portion are disposed to extend in the planetary radial direction.