Multi-Speed Countershaft Transmission Direct Coupling
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Solution Overview
Problem
Existing countershaft transmissions in motor vehicles require a separate direct shaft and headset gears, which increase complexity, weight, and cost, while also introducing torsional effects and limiting power take-off options.
Innovation Solution
A transmission design that eliminates the need for a direct shaft by directly coupling the main shaft to the countershaft gears, using a planetary gear set and multiple torque transmitting mechanisms to achieve up to ten forward and two reverse speed ratios, with torque multiplication occurring near the output end, reducing overall length and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a separate direct shaft and headset gears are used in countershaft transmissions, then torque can be transmitted directly to bypass countershafts, but the device complexity, weight, and length increase
Solution Approach 1:
The patent merges the direct shaft functionality into the main shaft by providing direct coupling between the input member and the main shaft. This eliminates the need for a separate direct shaft while maintaining the ability to transmit torque directly to bypass countershafts, thereby reducing device complexity and part count.
Solution Approach 2:
The patent removes the headset gears and direct shaft from the transmission system. By eliminating these components, the design reduces weight, complexity, and length while retaining essential torque transmission capabilities through the main shaft and countershaft gear arrangement.
2Productivity
If a separate direct shaft is used to bypass countershafts, then power transmission efficiency is improved, but the weight and length of the transmission increase
Solution Approach 1:
The direct shaft functionality is merged into the main shaft structure. The main shaft is directly coupled to the input member, allowing torque to bypass countershafts when needed, achieving power transmission efficiency without requiring additional weight-bearing components.
Solution Approach 2:
The separate direct shaft is removed from the system. By eliminating this redundant component, the transmission weight is reduced while maintaining efficient power transmission pathways through the integrated main shaft design.
3Adaptability or versatility
If headset gears and direct shaft are included in the transmission, then multiple speed ratios can be achieved, but the overall length and part count increase
Solution Approach 1:
The transmission integrates multiple gear sets (first and second countershaft gear sets) directly onto the main shaft and countershafts without requiring a separate direct shaft. This merging of functions allows achievement of multiple speed ratios in a more compact arrangement.
Solution Approach 2:
The headset gears are removed from the transmission system. By eliminating these components, the overall length of the transmission is reduced while the remaining gear sets maintain the capability to provide multiple forward and reverse speed ratios.
4Adaptability or versatility
If multiple shafts and gear sets are used to provide multiple speed ratios, then transmission versatility is improved, but torsional effects are introduced
Solution Approach 1:
The direct shaft is removed from the system, eliminating a source of torsional effects. The remaining design uses the main shaft and countershaft gear arrangement to provide multiple speed ratios without the additional torsional interference that would be introduced by a separate direct shaft.
Data Source
AI summary
A multi-speed countershaft transmission for a vehicle is provided. The transmission includes a main shaft and countershaft gears that receive input directly from an input member. A plurality of torque transmitting mechanisms may be selectively applied to synchronize a range gear to a countershaft. The countershaft transfers torque to an output gear set, which may transfer torque to a planetary gear set. The available range gears include a plurality of forward speed ratios and at least one reverse speed ratio. One or more power take-off sections may also be provided.