Jaw-Type Gearshift With Shift Gate Synchronization for Quiet Shifting
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Solution Overview
Problem
Gearboxes in electromotively driven and hybrid vehicles experience interruptions in tractive power and noise issues during shifting due to the requirement of large pockets for jaw engagement, leading to load shocks and axial stop-related noises.
Innovation Solution
A jaw-type gearshift with a ring-shaped shift gate and flying toothing that synchronizes the gear wheel with the shifting gate, allowing the shifting jaws to engage in receptacles without resistance, reducing noise and axial movement, and featuring a pivoting shifting gate and axially protruding selection jaws that adjust rotational speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If large pockets are provided for jaw engagement, then the jaw can engage freely, but noises and load shocks occur during shifting
Solution Approach 1:
The patent applies preliminary action by introducing synchronization jaws that engage in synchronization pockets before the main shifting jaws engage in the gear wheel. This preliminary engagement synchronizes the rotational speeds of the gear wheel and gear shaft, ensuring that when the shifting jaws subsequently engage, there is minimal speed difference, thereby reducing noise and load shocks while maintaining free engagement capability
Solution Approach 2:
The synchronization jaws and synchronization pockets act as intermediaries between the gear shaft and the gear wheel. These intermediary elements facilitate smooth speed matching before the main power transmission engagement, reducing the harmful effects of direct engagement between mismatched rotating components
2Ease of operation
If axial stop is used for shifting, then the gearshift can be controlled, but noises occur during shifting
Solution Approach 1:
The synchronization mechanism performs preliminary speed matching before the axial stop engages the main shifting jaws. By the time the axial stop controls the final engagement, the rotational speeds are already synchronized, eliminating the noise that would otherwise occur during the controlled stopping and engagement process
3Ease of manufacture
If high forces are applied to insert the jaw, then the jaw can be inserted, but the shifting operation becomes harsh and noisy
Solution Approach 1:
The synchronization jaws engage first to match rotational speeds before the main shifting jaws are inserted. This preliminary speed synchronization ensures that when high insertion forces are applied to the shifting jaws, the relative speed between mating surfaces is minimal, reducing noise and harshness while maintaining the necessary insertion force capability
Solution Approach 2:
The synchronization mechanism provides beforehand cushioning by gradually matching speeds before the main engagement. This gradual synchronization cushions the subsequent high-force insertion of the shifting jaws, preventing sudden impacts and reducing noise during the insertion operation
Data Source
AI summary
In a jaw-type gearshift for an at least two-stage gearbox, which is in particular electromotively driven, a ring-shaped shifting gate with a sliding block guide is provided, which has axially protruding shifting jaws and is in shifting contact by means of a shifting finger arranged on the sliding sleeve and engaging in the sliding block guide. In a method for shifting the jaw-type gearshift, the shifting jaws are coupled into corresponding receptacles of the gear wheels in that the shifting gate is moved axially relative to the sliding sleeve and the rise of the sliding block guide.