Synchronizer Pre-Synchronization Ball Wear Reduction
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Solution Overview
Problem
Existing synchronizer designs for vehicle transmissions face issues with wear and early breakage of springs due to continuous compression and bending, and serious wear of ball heads on studs from sliding, leading to reduced lifespan.
Innovation Solution
The synchronizer design features separate, rollable balls on support plates or planes of studs, made from higher hardness materials, reducing wear and allowing for longer life without significant cost increase, with springs indirectly urging balls radially outward and studs made from lower hardness materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If springs are used to load balls in the pre-synchronizing device, then the balls can be urged radially outward to engage with the actuating sleeve, but the springs are continuously stressed under compression and bending leading to early breakage
Solution Approach 1:
The patent extracts the ball from the stud, making them separate components. The ball is no longer integrated with the stud but is instead a separate element that can roll on the stud's support plate. This separation allows the ball to be made from higher hardness material while the stud remains from lower hardness material, reducing wear on both components and eliminating the spring's bending stress by allowing the ball to roll rather than slide.
Solution Approach 2:
The patent changes the material parameter of the ball to higher hardness material, while keeping the stud material as lower hardness. This parameter change allows the ball to withstand wear better during rolling contact, and the material difference creates a favorable wear pattern where the softer stud can be replaced more easily if needed.
2Reliability
If ball heads on studs are used in the pre-synchronizing device, then the balls can be supported by the studs, but serious wear occurs on the ball heads due to sliding
Solution Approach 1:
The patent utilizes the spherical shape of the ball to enable rolling motion on the stud's support plate. This curvature allows the ball to roll rather than slide, transforming the friction type from sliding friction (which causes serious wear) to rolling friction (which causes minimal wear). The spherical geometry is essential for achieving the rolling contact that extends component life.
Solution Approach 2:
The patent replaces the sliding mechanical contact between ball head and stud with a rolling contact mechanism. By allowing the ball to roll on the support plate instead of sliding, the mechanical interaction changes from high-wear sliding friction to low-wear rolling friction, significantly extending the service life of both the ball and stud components.
3Reliability
If balls are made from higher hardness materials to reduce wear, then wear resistance improves, but manufacturing cost increases
Solution Approach 1:
The patent applies local quality by using higher hardness material only for the ball component where wear resistance is critical, while keeping the stud made from lower hardness material. This localized application of high-performance material focuses the cost investment on the specific component that benefits most from wear resistance, rather than upgrading all components uniformly.
Solution Approach 2:
The patent creates a composite material system where the ball and stud are made from different materials with complementary properties. The high-hardness ball provides wear resistance during rolling contact, while the lower-hardness stud provides ease of manufacturing and replacement. This material differentiation optimizes both performance and cost by matching material properties to functional requirements.
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 design significantly extends the synchronizer's life by minimizing wear and stress on components, particularly beneficial in high-actuation applications like vehicle robotized transmissions.
Implementation Method 1
a corresponding plurality of springs each acting indirectly on a respective ball so as to urge this latter radially outwards
Implementation Method 2
the balls being made as separate components from the studs and being arranged so as to be free to roll on respective support plates or planes of the studs
Data Source
Figure 1
Figure 2~4
AI summary
The synchronizer (10) comprises: a hub (12), an actuating sleeve (14), a pre-synchronizing device (16) and two synchronizing rings (18) each having a conical surface (22). The pre-synchronizing device (16) comprises three balls (42) partially received in respective notches (44) in the actuating sleeve (14), three blocks (46) each having a radial through hole (48) in which a respective ball (42), whereby the blocks are urged via the balls (42) against the respective synchronizing ring (18) when the actuating sleeve (14) is axially moved towards the ring, three springs (52) interposed each between a respective ball (42) and the hub (12) to exert on the ball (42) a force tending to hold the ball within the respective notch (44). The pre-synchronizing device (16) further comprises three studs (54) interposed each between a respective ball (42) and a respective spring (52), each stud (54) comprising a support plate or plane (60) for supporting the respective spring (52), an abutment surface (62) for the radially outer end of the respective spring (52), and a shank (64) inserted into the respective spring (52) through at least the largest part of the length thereof, and three support members (56) interposed each between the hub (12) ad the respective spring (52) and resting on the hub (12) so as to be tiltable relative thereto.