Transfer Case Overdrive Mode via Sliding Hub
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Solution Overview
Problem
Current transfer cases in drive trains do not adequately address the need for increased fuel efficiency in vehicles, particularly in response to rising fuel prices and environmental concerns, as they lack efficient power distribution mechanisms that could enhance fuel economy.
Innovation Solution
A transfer case design featuring a sun gear, a hub that slidably moves between positions to lock the sun gear to either the input shaft or the housing, and a carrier body with planetary gears, allowing for direct drive, overdrive, and neutral modes, enabling efficient power transmission and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional transfer case designs are used, then the vehicle can operate, but fuel efficiency is not optimized due to lack of overdrive mode
Solution Approach 1:
The transfer case employs a dynamic hub that can slide between positions to engage different gear modes. The hub moves along the input shaft to selectively engage the sun gear with either the input shaft (for overdrive mode) or the ring gear (for standard mode), enabling the system to adapt its gear ratio dynamically based on operating conditions to optimize fuel efficiency.
Solution Approach 2:
The invention changes the gear ratio parameter by engaging different gear configurations. By switching between overdrive mode (gear ratio < 1:1) and standard mode (1:1 gear ratio), the system optimizes the transmission parameter to reduce fuel consumption during normal driving conditions while maintaining capability for high-torque situations.
2Use of energy by moving object
If overdrive mode is added to reduce fuel consumption, then fuel efficiency improves, but device complexity increases
Solution Approach 1:
The planetary gear set serves multiple functions: it enables both overdrive mode and standard 1:1 mode within a single transfer case unit. The same planetary gears, sun gear, and ring gear configuration provide both gear reduction and overdrive capabilities, eliminating the need for separate gear sets and reducing overall system complexity despite adding functional versatility.
Solution Approach 2:
The sun gear is nested within the planetary gear structure, and the hub is positioned to engage components within the existing gear assembly. This nested arrangement allows the overdrive mechanism to be integrated into the conventional transfer case architecture without requiring separate external components, thereby minimizing the increase in device complexity.
3Adaptability or versatility
If a hub that slidably moves is used to lock sun gear to input shaft or housing, then gear mode switching is enabled, but manufacturing precision requirements increase
Solution Approach 1:
The hub acts as an intermediary component that mediates between the input shaft and the sun gear. It provides a controlled engagement interface with engagement surfaces and locking features that guide precise positioning during assembly and operation. This intermediary structure distributes the precision requirements across multiple contact surfaces rather than requiring extreme precision in a single location.
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 transfer case design enhances fuel efficiency by providing an overdrive mode with a gear ratio less than 1:1, optimizing power transmission and reducing fuel consumption in vehicles.
Implementation Method 1
a plurality of planetary gears mounted in a carrier body may circumscribe the gear end
Implementation Method 2
the carrier body splined with the transfer case input shaft
Data Source
AI summary
A transfer case (18) is disclosed. The transfer case (18) includes an input shaft (16) and a sun gear (56). The sun gear (56) includes a collar end (58) and a gear end (60) and at least a portion of the sun gear (56) circumscribes the input shaft (16). A hub (62) circumscribes the collar end (58) and the input shaft (16), and may be slidably move between a first position (64) and a second position (66) opposite the first position (64) along the input shaft (16) and the collar end (58). A plurality of planetary gears (70) is mounted in a carrier body (72) circumscribing the gear end (60), and the carrier body (72) is splined with the transfer case input shaft (16). A ring gear (78) circumscribes the plurality of planetary gears (70) mounted in the carrier body (72), and is integrally joined with an output shaft (20). The ring gear (78) is rotatable around the plurality of planetary gears (70).