Transmission Synchronizer Unit With Decoupled Spring Latching
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Solution Overview
Problem
Conventional synchronization units in motor vehicle transmissions experience friction and wear due to the rotational movement of the compression spring during pre-synchronization, leading to undesirable drag losses and noise.
Innovation Solution
The synchronization unit decouples the latching element from the spring element during rotary movement, maintaining the synchronizing ring at a defined distance via a locking recess and spring element, preventing friction contact with the clutch body or gear wheel, and uses alternately arranged synchronizing ring drivers for central locking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pre-synchronization element and compression spring are coupled to the synchronizer ring as a single assembly, then the synchronizer ring can be axially displaced for pre-synchronization, but the compression spring generates friction and drag losses during rotational movement of the synchronizer ring
Solution Approach 1:
The patent divides the pre-synchronization assembly into separate functional components: the compression spring is separated from the synchronizer ring, allowing the spring to remain stationary while the synchronizer ring rotates freely during the synchronization process. This segmentation eliminates the friction and drag losses caused by the coupled design.
Solution Approach 2:
The compression spring is extracted from the rotating assembly and fixed to the guide sleeve, removing it from the rotational path of the synchronizer ring. This extraction eliminates the source of friction and drag losses while preserving the pre-synchronization function through the spring's axial force application.
2Productivity
If the compression spring is held against the sliding sleeve to initiate pre-synchronization, then the pre-synchronization process can be activated, but friction and wear occur during the rotational movement into the locked position
Solution Approach 1:
The patent segments the spring support structure from the rotating synchronizer ring components. The spring is anchored to the stationary guide sleeve while acting on the synchronizer ring through the pre-synchronization element, allowing rapid synchronization without compromising wear resistance.
Solution Approach 2:
The pre-synchronization element acts as an intermediary between the compression spring and the synchronizer ring. It transmits the axial force from the spring to the ring during the synchronization process, enabling fast engagement while preventing direct friction contact between the spring and the rotating ring during the locked position transition.
3Loss of energy
If the synchronizer ring is freely rotatable during pre-synchronization, then drag losses are minimized in the unshifted state, but friction contact occurs with the clutch body or gear wheel during rotational movement
Solution Approach 1:
The patent implements a dynamic system where the synchronizer ring's rotational freedom is selectively controlled. During normal operation, the ring can rotate freely to minimize drag losses. During the synchronization process, the conical friction surfaces dynamically engage to provide controlled friction for speed matching, then disengage to allow friction-free rotation into the locked position.
Solution Approach 2:
The patent ensures continuous useful action by maintaining the synchronizer ring's ability to rotate freely when not engaged, minimizing drag losses throughout idle periods. The friction contact occurs only continuously during the brief synchronization transition when it is functionally necessary, then ceases to allow friction-free operation in the engaged state.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution reduces friction, minimizes wear, and eliminates synchronizer ring noise by allowing the synchronizing ring to switch into the locked position without friction, enhancing the overall efficiency and reliability of the synchronization process.
Implementation Method 1
a spring element (23a, 23b) assigned to each pre-synchronization unit (20a, 20b), wherein the spring element (23a, 23b) acts on the latching element (21a, 21b)
Implementation Method 2
a friction pair formed between the synchronizer ring and the clutch body via corresponding conical surfaces
Data Source
Figure 1
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AI summary
The invention relates to a synchronising unit (1) for a motor vehicle transmission, with: a guide sleeve (3), which can be non-rotatably secured to a transmission shaft and has an outer toothing (4); a sliding sleeve (11), which has an inner toothing (10), engages with the outer toothing (4) of the guide sleeve (3) via the inner toothing (10) and is mounted axially displaceably relative to the guide sleeve (3); at least one synchroniser ring (8a, 8b), which is axially displaceable relative to the guide sleeve (3) and is mounted rotatably to a limited extent; and a number of pre-synchronisation units (20a, 20b), which act between the sliding sleeve (11) and the synchroniser ring (8a, 8b) in such a way that the synchroniser ring (8a, 8b) is axially displaceable in the event of an axial displacement of the sliding sleeve (10), wherein: the pre-synchronisation units (20a, 20b) comprise a spring element (23a, 23b), a latching member (22a, 22b) and a synchroniser ring driver element (21a, 21b); the synchroniser ring driver element (21a, 21b) is fixedly attached to the synchroniser ring (8a, 8b) in the axial direction; the latching member (22a, 22b) is supported in a spring-preloaded manner on a recess (25a, 25b) of the sliding sleeve (10) and is held on the synchroniser ring driver element (21a, 21b) for transfer of the axial displacement movement; and in the event of rotary motion between the guide sleeve (3) and synchroniser ring (8a, 8b), a relative movement between the latching member (22a, 22b) and synchroniser ring driver element (21a, 21b) is possible.