Wheel Hub Drive Sealing and Torque Amplification
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Solution Overview
Problem
Existing wheel hub drive systems face high dynamic demands on brakes and large component dimensions, leading to increased wear and reduced service life of sealing parts due to friction and linear velocity issues.
Innovation Solution
The wheel hub drive unit design positions the reduction gear between the brake and wheel hub mounting surface, with the electric machine chamber's passage extending towards the central axis, and uses lip-shaped sealing rings to reduce friction and wear by positioning the sealing parts closer to the central axis, allowing the reduction gear to boost both driving and braking torque, thereby reducing brake demands and component dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the brake is positioned close to the wheel hub mounting surface to provide sufficient braking torque, then the braking performance is improved, but the dynamic demands on the brake increase and the component dimensions become large
Solution Approach 1:
The patent repositions the brake from a radial arrangement (close to the wheel hub mounting surface) to an axial arrangement (distributed along the axial direction away from the mounting surface). This dimensional change allows the brake to provide sufficient braking torque while reducing the radial space required, thereby decreasing brake component dimensions and simplifying the overall structure.
Solution Approach 2:
The reduction gear is designed to serve dual functions: both transmitting driving torque from the electric machine and amplifying braking torque from the brake. This multi-functionality allows the brake to be positioned axially away from the mounting surface while still achieving sufficient braking performance through the torque amplification effect of the reduction gear, thus reducing brake component dimensions without compromising braking capability.
2Reliability
If the sealing part of the electric machine chamber is arranged close to the inner peripheral surface of the wheel hub away from the central axis, then the electric machine chamber is effectively sealed, but the linear velocity of the sealing part becomes too high during vehicle operation, causing excessive friction and severe wear
Solution Approach 1:
The patent applies different sealing strategies to different locations within the electric machine chamber. The sealing part is specifically positioned at the radially inner end of the passage (closer to the central axis) rather than uniformly distributing sealing elements throughout the chamber. This localized sealing approach maintains effective sealing at critical interfaces while minimizing the rotational velocity of sealing surfaces, thereby reducing friction and wear.
Solution Approach 2:
The passage structure serves as an intermediary element that connects the electric machine chamber to the external environment while providing a controlled sealing interface. By positioning the sealing part at the radially inner end of this passage (closer to the central axis), the design mediates between the need for effective sealing and the need to minimize sealing part velocity, reducing direct exposure of sealing surfaces to high-speed rotation.
3Power
If the reduction gear is positioned between the brake and wheel hub mounting surface, then both driving and braking torque can be boosted, but the space arrangement becomes more complex
Solution Approach 1:
The patent merges the functions of the reduction gear and brake into a closely integrated assembly where the reduction gear is positioned between the brake and the wheel hub mounting surface. This merging allows the reduction gear to simultaneously handle both driving torque transmission and braking torque amplification, achieving dual torque boosting capability while minimizing the overall spatial footprint through functional integration.
Solution Approach 2:
The patent utilizes the axial dimension to arrange the reduction gear and brake components, distributing them along the axial direction away from the wheel hub mounting surface. This axial arrangement provides sufficient space for both components to perform their torque boosting functions while maintaining a compact radial profile, thus managing spatial complexity through three-dimensional optimization.
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 reduces the dynamic demands on the brake, minimizes component size, and extends the service life of sealing parts by lowering linear velocity and friction, resulting in cost savings and improved performance.
Implementation Method 1
the linear velocity of the sealing part is too high during the running of the vehicle and the friction between the sealing part and the sealing surface is too large
Data Source
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AI summary
A wheel hub drive unit, wherein a housing (500) arranged in the wheel hub (110) forms a sealed electric motor chamber equipped with an electric drive motor (200), a sealed reduction gear chamber equipped with a reduction gear (400), and a brake chamber connected to the outside environment and equipped with a brake (300), wherein the reduction gear chamber and the brake chamber are distributed along an axial direction away from a wheel hub mounting surface; the electric motor chamber comprises a base body (Q1) arranged close to the inner circumferential surface of the wheel hub and a passage (Q2) extending in the direction towards the central axis of the wheel hub;The output end of the electric drive motor is guided through the passage and then extended out of the electric motor chamber, simultaneously connected to the input end of the reduction gear and the output end of the brake, with the output end of the reduction gear being connected to the wheel hub; and the housing (500), at the position located near the radial inner end of the passage, seals the electric motor chamber towards the rotor mount with a sealing element. The reduction gear (400) can simultaneously amplify the drive torque as well as the braking torque and reduces the dynamic demands on the electric drive motor and the brake; and the closer proximity of the sealing element to the central axis of the wheel hub reduces its wear rate.