Pivoting Variable Speed Transmission for Zero Turn Radius
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Solution Overview
Problem
Existing drive assemblies for vehicles, such as snow throwers and lawn mowers, lack flexibility and efficiency in power transmission, particularly in providing zero turn radius capability and enabling movement of temporarily unpowered vehicles.
Innovation Solution
The implementation of a variable speed transmission system that can be pivoted or rigidly mounted, incorporating mechanical clutches at the output shaft and gear trains to allow for clutch-enabled steering and movement of unpowered vehicles, with configurations including through-shaft outputs and dual transmissions for enhanced maneuverability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a variable speed transmission is pivoted from a disengaged position to an engaged position, then the transmission can be disengaged for easy movement of unpowered vehicles, but the mounting complexity increases
Solution Approach 1:
The transmission is mounted on a pivoting arrangement that allows it to move between a disengaged position (where the output shaft is disconnected from the drive wheel) and an engaged position (where power is transmitted). This dynamic mounting enables easy movement of unpowered vehicles while maintaining power transmission capability when needed.
2Adaptability or versatility
If mechanical clutches are added to the output shaft of each transmission, then steering capability and movement of unpowered vehicles are enabled, but the device complexity increases
Solution Approach 1:
The clutch mechanism is segmented into discrete components including a clutch body, clutch disc, and actuating mechanism that can be independently assembled and maintained. The clutch is integrated with the transmission output shaft, allowing it to be engaged or disengaged to enable steering or movement of unpowered vehicles.
3Adaptability or versatility
If two variable speed transmissions are rigidly mounted to provide zero turn radius capability, then maneuverability is improved, but the mounting complexity and space requirements increase
Solution Approach 1:
Two variable speed transmissions are rigidly mounted to the vehicle frame in a combined arrangement where both transmissions work together to drive separate drive wheels. This merging of two transmission systems enables zero turn radius capability by allowing independent control of each drive wheel, achieving superior maneuverability.
4Productivity
If a through-shaft output transmission is mounted to provide power to two drive wheels, then power distribution efficiency is improved, but the complexity of clutch integration increases
Solution Approach 1:
The through-shaft output transmission is designed with universal mounting capabilities that allow it to power two drive wheels efficiently. Mechanical clutches are integrated at both ends of the output through-shaft, enabling the same transmission component to serve multiple functions: power distribution to both wheels, steering control, and movement of unpowered vehicles.
Data Source
AI summary
A drive assembly for a vehicle is provided, the vehicle having a frame, a prime mover and a pair of driven wheels. The drive assembly includes a transmission having a housing in which a pump and motor may be disposed. The transmission may be pivotally mounted to the frame and movable between at least two positions. The transmission may include an internal reduction gear assembly driven by a motor output shaft, a transmission output shaft disposed generally parallel to the motor output shaft and driven by the internal reduction gear assembly, the transmission output shaft extending from the transmission at both ends thereof. Each end of the transmission output shaft may drive an external reduction assembly supported in part by the frame, and the external reduction assemblies power at least a driven wheel of the vehicle.