Final Drive Device Axle Dimension Reduction
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Solution Overview
Problem
Conventional final drive devices with built-in differential gear mechanisms require space for a differential case, increasing the axle direction dimension and overall size, which is a challenge in miniaturization.
Innovation Solution
The final drive device integrates a final drive gear mechanism with a drive pinion and ring gear, and a differential gear mechanism with pinions supported by a pinion mate shaft and side gears, where the pinion carrier is rotated around the axle and fixed to the ring gear, eliminating the need for a differential case and allowing the side gears to be fixedly positioned relative to the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a differential case is used to fix the positional relationships among the ring gear, pinion gear, and side gear, then the reliability of the differential function is improved, but the axle direction dimension is increased
Solution Approach 1:
The invention extracts and eliminates the differential case from the conventional differential gear mechanism. By removing this unnecessary component, the patent achieves miniaturization in the axle direction while maintaining the differential function through direct positioning of the side gears relative to the housing.
Solution Approach 2:
The housing is given a dual function: it serves as both the housing structure and the positioning element for the side gears. The side gears are directly positioned relative to the housing, eliminating the need for a separate differential case while maintaining reliable positional relationships.
2Ease of manufacture
If space is allocated for the differential case between the differential gear mechanism and the housing, then the assembly and maintenance ease is improved, but the device size is increased
Solution Approach 1:
The differential case is extracted from the system, removing the need for additional space between the differential gear mechanism and the housing. This extraction enables device miniaturization while the direct positioning approach simplifies the assembly structure.
Solution Approach 2:
The positioning function previously performed by the differential case is merged into the housing structure itself. The side gears are directly positioned relative to the housing, combining the housing's structural role with the positioning role, thereby eliminating redundant space and components.
Data Source
AI summary
A final drive device includes a housing and a final drive gear mechanism. The final drive gear mechanism is provided in the housing, and comprises a drive pinion and a ring gear meshed with the drive pinion and a differential gear mechanism. The differential gear mechanism includes a pinion rotatably supported by a pinion mate shaft, and a pair of side gears meshed with the pinion from both sides in an axle direction. The final drive device has a pinion carrier that is rotated in a direction around the axle integrally with the pinion mate shaft supporting the pinion, and which is secured to the ring gear. The pinion carrier is provided with a pinion housing unit that houses the pinion while permitting the pinion to rotate around its own axis. The side gears are fixedly located relative to the housing while being permitted to rotate around their own axes.