Clutchless SIVRT Geartrain for Continuous Torque Transfer
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Solution Overview
Problem
Existing robotic-automatic transmissions for heavy-duty, diesel-powered vocational vehicles, such as refuse trucks, are unreliable and cost-ineffective due to frequent transmission failures during low-speed, stop-start, and stop-reverse operations, as they were not designed for these unique conditions.
Innovation Solution
The SIVRT geartrain provides a clutch-free, mechanical transmission with a variably scalable geartrain system, incorporating VariGyro and VariSpeed assemblies, which allows continuous, stepless gear ratio selection and torque transfer, eliminating the need for mechanical clutches and traditional shift mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If robotic-automatic transmissions are used for heavy-duty vocational vehicles, then fuel economy and emissions compliance are improved, but reliability deteriorates due to frequent transmission failures during stop-start-reverse operations
Solution Approach 1:
The patent removes clutches from the transmission system entirely, extracting the failure-prone component that causes reliability issues during stop-start-reverse operations. The clutchless design eliminates the main source of transmission failures while maintaining the required functionality through a simplified geartrain architecture.
Solution Approach 2:
Instead of using traditional automatic transmissions with multiple clutches and complex shifting mechanisms, the patent inverts the approach by using a mechanical clutchless geartrain with direct mechanical engagement. This reversal of the conventional design philosophy leads to improved reliability for vocational vehicle applications.
2Reliability
If traditional automatic transmissions with clutches are used, then gear ratio changes are achieved, but transmission failures occur frequently during repeated stop-start-reverse operations
Solution Approach 1:
The patent ensures continuous torque transfer through the geartrain without interruption by clutches. The mechanical engagement system maintains continuous operation during stop-start-reverse sequences, eliminating the operational interruptions and failures associated with traditional clutch-based transmissions.
Solution Approach 2:
The patent replaces the mechanical clutch system with a purely mechanical geartrain engagement mechanism. This substitution eliminates the friction-based clutch components that fail during repeated engagement/disengagement cycles, providing more durable operation for vocational vehicles.
3Reliability
If multi-speed robotic transmissions are used to comply with fuel economy rules, then fuel efficiency is improved, but cost-effectiveness deteriorates due to frequent transmission breakdowns
Solution Approach 1:
The patent divides the transmission into distinct mechanical stages (input shaft, intermediate shafts, output shaft with specific gear ratios) that can be manufactured and assembled separately. This segmentation simplifies manufacturing while ensuring reliable operation through proven mechanical geartrain design principles.
Solution Approach 2:
The patent optimizes specific gear ratio parameters (2.27:1, 1.00:1, 0.44:1) to match the operational requirements of vocational vehicles. These parameter changes ensure fuel efficiency compliance while maintaining reliability through appropriately selected mechanical ratios rather than relying on complex electronic control systems.
Data Source
AI summary
A geartrain includes a first planetary carrier supported on a input shaft, wherein the first planetary carrier has two or more first planetary gears that engage a first sun gear supported on a first intermediate shaft. A first ring gear engages the two or more first planetary gears and a first stationary gear supported on a first auxiliary shaft. A first gear is supported on the first intermediate shaft. A second gear is supported on a second intermediate shaft that engages the first gear. A third gear is supported on a second auxiliary shaft that engages the second gear. A second planetary carrier is supported on an output shaft, wherein the second planetary carrier has two or more second planetary gears that engage a second sun gear) supported on the first intermediate shaft. A second ring gear engages the two or more second planetary gears and a second stationary gear supported on the first auxiliary shaft.