Vehicle Gearbox Axial Stop and Coupling Sleeve Design
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Solution Overview
Problem
Existing range gearboxes for heavy vehicles face issues with slow shift times, high repair costs, increased noise, and axial forces on main shaft bearings, while also being inefficient in torque transmission and energy consumption.
Innovation Solution
The gearbox design incorporates axially shiftable coupling sleeves with splines and an axial stop to minimize axial movement, reduce wear, and allow for quick gear shifting, along with oblique teeth and splines to reduce noise and stress on components, enabling efficient torque transmission and simplified repair.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the ring gear is axially shifted between low and high range positions in prior art range gearboxes, then gear ratio change is achieved, but shift time increases and reliability decreases
Solution Approach 1:
The invention divides the single ring gear into two separate ring gears (first ring gear and second ring gear), each handling different gear ranges. The first ring gear handles low range gears while the second ring gear handles high range gears. This segmentation eliminates the need for axial shifting between ranges, as each ring gear remains in a fixed axial position, thereby reducing shift time and improving reliability.
Solution Approach 2:
The invention introduces a first coupling sleeve as an intermediary component that selectively connects the input shaft to either the first planetary gear set (low range) or the second planetary gear set (high range). This coupling sleeve acts as a mediator that redirects power flow without requiring axial movement of the ring gears, enabling fast and reliable gear range switching.
2Reliability
If synchronisation rings with locking angles are used to achieve synchronous gear shifting, then synchronous rotational speed is achieved, but the structure becomes complex and repair costs increase
Solution Approach 1:
The invention extracts and eliminates the synchronisation rings with locking angles from the gearbox design. Instead of using complex synchronisation mechanisms, the patent relies on the inherent torque balance between the two planetary gear sets during range switching. This simplification removes the need for synchronisation rings, reducing structural complexity and repair costs while maintaining reliable gear shifting.
3Object-generated harmful factors
If oblique teeth are used in planetary gears, then noise is reduced, but axial reaction forces increase on main shaft bearings
Solution Approach 1:
The invention segments the torque transmission path into two separate planetary gear sets operating in different gear ranges. By keeping each ring gear in a fixed axial position and avoiding axial shifting, the system minimizes the cumulative axial reaction forces on the main shaft bearings. The segmentation allows each gear set to handle axial loads independently, reducing the overall impact on bearings.
4Adaptability or versatility
If the ring gear is allowed to shift axially for gear changing, then gear ratio adjustment is achieved, but wear increases and repair costs increase
Solution Approach 1:
The invention segments the gear system into two independent planetary gear sets with fixed axial positions for each ring gear. This eliminates axial movement and wear associated with single-ring-gear systems. Each ring gear remains stationary in its designated axial position, significantly reducing wear and improving reliability while maintaining full gear ratio adjustment capability through the coupling sleeve mechanism.
Data Source
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AI summary
The invention relates to a gearbox (2) for vehicles, comprising a planetary gearbox (14) with a ring gear (22), a sun wheel (18) and a planetary wheel carrier (20), on which at least one planetary wheel (24) is mounted in a rotatable manner, which ring gear (22) and sun wheel (18) engage with the at least one planetary wheel (24) through teeth (32); a first axially shiftable coupling sleeve (40), which in first gear position is arranged to disconnect an input shaft (16) to the gearbox (2) from the planetary wheel carrier (20), and in a second gear position is arranged to connect the input shaft (16) with the planetary wheel carrier (20); and a second axially shiftable coupling sleeve (42), which in the first gear position is arranged to connect a gearbox house (12) surrounding the planetary gearbox (14) with the ring gear (22), and in the second gear position is arranged to disconnect the gearbox house (12) from the ring gear (22). An axial stop (54), mounted stored on the planetary wheel carrier (20), abuts against and is connected with the ring gear (22), which axial stop (54) prevents the ring gear (22) from shifting axially. The invention also relates to a vehicle (1) comprising such a gearbox (2).