Two-Speed Gearbox Clutch Layout for Shift Without Torque Interruption
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Solution Overview
Problem
Current electric vehicle gear assemblies are bulky and require large volumes for clutch actuation, making them inefficient in terms of space and maintenance, and they often experience torque interruptions during gear shifting.
Innovation Solution
A compact gear assembly design with a shaft having gears at both ends, connected to clutch members, where a force member axially moves the clutches to engage and disengage at relative circumferential speeds, utilizing hydraulic actuators and an interconnecting plate for smooth torque transfer and reduced noise, allowing for easy assembly and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If clutches are placed on the input shaft, then gear shifting can be achieved, but centrifugal forces cause oil to be forced out at high speeds
Solution Approach 1:
The patent introduces an intermediate shaft (lay shaft) as a mediator between the input shaft and the differential. The clutches are positioned on this intermediate shaft rather than directly on the input shaft, allowing gear shifting to occur at lower speeds where centrifugal forces are reduced, thus preventing oil from being forced out while maintaining full gear shifting functionality.
2Ease of operation
If a parallel shaft layout with intermediate shaft is used, then gear transmissions can be achieved, but the radial volume becomes relatively large
Solution Approach 1:
The patent transitions from a traditional parallel shaft layout to a coaxial shaft arrangement where the input shaft, intermediate shaft, and output shaft are aligned along the same axis. This dimensional reorganization allows the clutch actuation mechanisms to be positioned axially rather than radially, significantly reducing the radial volume while maintaining all necessary gear transmission functions.
3Adaptability or versatility
If clutch actuation mechanisms are added for 2-speed operation, then flexibility and torque control improve, but the device volume and complexity increase
Solution Approach 1:
The intermediate shaft serves multiple functions simultaneously: it carries the clutch assemblies for 2-speed operation, transmits torque between gears, and provides a mounting platform for the clutch actuation mechanisms. This multi-functionality allows the system to achieve enhanced flexibility and torque control without proportionally increasing device complexity, as the same structural element performs multiple roles.
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
The solution provides a compact, efficient gear shifting mechanism with constant torque transfer and reduced noise and wear, enabling cost-effective and flexible 2-speed gearbox operation without torque interruptions.
Implementation Method 1
The force member comprises, according to the invention, for each second clutch member a hydraulic actuator that is operated by the control circuit.
Implementation Method 2
the first clutch members and the second clutch members can engage and disengage in a slipping manner at relative circumferential speeds
Data Source
Figure 1~2
Figure 3~4A
Figure 4B~5
AI summary
The invention relates to an assembly for use with an electric motor (1), comprising a shaft (15) with on a first end and on a second end a rotatable gear (8,9). Each gear is fixedly connected to a first clutch member (24,25) that can slipping engage a second clutch member (26,27) extending around the shaft (15) and connected to the shaft in a fixed angular position. A force member (33,34, 37,38,46) is axially situated between the clutch members (10,11) for moving second clutch members (26,27) relative to the first clutch members (24,25) in an axial direction such that the first clutch members (24,25) and the second clutch members (26,27) can engage and disengage in a slipping manner at relative circumferential speeds.