Compact Gearing Assembly for Electric Wheel Hub
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Solution Overview
Problem
Existing gearing assemblies for electric hub drives require a complex mechanism to achieve multiple gear ratios, particularly when trying to incorporate a 1:1 ratio with planetary gear sets, due to the need for a dog clutch arrangement that complicates the axial direction, making it difficult to maintain compactness and simplicity.
Innovation Solution
A gearing assembly with a rotary input and output member, featuring a first engagement member for a 1:1 ratio on the opposite side of the input member from the planetary gear sets, and using two planetary gear stages in series to achieve additional gear ratios, with dog clutch arrangements and actuators for selective engagement, allowing for a compact and simplified mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a dog clutch arrangement is used to selectively engage planetary gear sets for multiple ratios, then multiple gear ratios including 1:1 can be achieved, but the mechanism becomes complex and axial length increases
Solution Approach 1:
The gearing assembly is divided into two separate planetary gear sets (first and second planetary gear stages) with distinct functions. The first planetary gear set handles the 1:1 ratio engagement through a first dog clutch, while the second planetary gear set handles the reduced ratios through a second dog clutch. This segmentation allows each clutch to be positioned on opposite sides of the input member, simplifying the overall mechanism layout and reducing axial length while maintaining multiple gear ratio capability.
2Volume of moving object
If a conventional single-sided dog clutch arrangement is used for 1:1 ratio engagement, then the mechanism can be compact, but the dog clutch becomes difficult to actuate and control
Solution Approach 1:
The invention positions the first dog clutch on the first side of the input member and the second dog clutch on the second side of the input member, utilizing both sides of the input member in the axial direction. This dimensional arrangement allows each clutch to be independently accessible and actuated from its respective side, improving ease of operation and control while maintaining overall compactness of the gearing assembly.
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 configuration enables a compact, three-speed gearing assembly that provides a large torque range and speed range, simplifying the mechanism by positioning the 1:1 engagement member opposite to the planetary gear sets, thus avoiding the complexity of conventional arrangements and allowing for efficient actuation of gear ratios.
Implementation Method 1
a first planetary gear stage and a second planetary gear stage
Implementation Method 2
a first torque connection in a 1:1 ratio, a second torque connection through the first planetary gear stage, and a third torque connection through the first and second planetary gear stages in series
Data Source
Figure 1
AI summary
The invention provides a gearing assembly (1) comprising a rotary input member (5) and a rotary output member (2) and a gearing arrangement between the input member (5) and the output member (2) selectively engageable to effect a driving engagement between the input member (5) and the output member (2) through at least a first torque connection having a first gear ratio, a second torque connection having a second gear ratio and a third torque connection having a third gear ratio. The gearing arrangement includes a first engagement member (19) operable selectively to effect the first torque connection in a 1:1 ratio, a first planetary gear stage (14) and a second planetary gear stage (15), and a second engagement member (13) operable selectively to effect the second torque connection and a third engagement member (12) operable selectively to effect the third torque connection respectively through one or more of the planetary gear stages. The first engagement member (9) is located on a first side of the input member (5) and the first planetary gear stage (14), second engagement member (13), second planetary gear stage (15) and third engagement member (12) are located on a second side of the input member (5) opposite to said first side. An electrical wheel hub drive having such a gearing mechanism is also provided.