In-Wheel Motor Brake Integration Using Stator-Mounted Calipers
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Solution Overview
Problem
Existing vehicle wheel drive devices with integrated in-wheel motors face challenges in efficiently integrating a brake device, leading to increased axial length and complex fixing structures.
Innovation Solution
A vehicle wheel drive device is designed with a rotary electric machine and a brake device, where the brake device is installed in a hollow space formed by the magnetic circuit unit of the rotary electric machine, and the brake caliper is fixed to the axial end surface of the stator, allowing for a reduced axial length and simplified fixing structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the brake device is integrated with the in-wheel motor structure, then the brake device can be installed within the wheel assembly, but the axial length of the drive device increases and the fixing structure becomes complex
Solution Approach 1:
The brake device is nested within the hollow space formed by the magnetic circuit unit of the rotary electric machine. The brake disc is positioned within the hollow space, and the brake caliper is mounted on the outer periphery of the magnetic circuit unit, effectively utilizing the existing structural space without increasing the overall axial length of the drive device.
Solution Approach 2:
Instead of extending the brake device axially, the invention repositions the brake caliper to be mounted on the outer periphery of the magnetic circuit unit in the radial direction. This dimensional shift from axial arrangement to radial arrangement reduces the axial length while still providing effective brake integration within the wheel assembly.
2Volume of moving object
If the brake device is integrated with the in-wheel motor structure, then the brake device can be installed within the wheel assembly, but the fixing structure becomes complex
Solution Approach 1:
The magnetic circuit unit of the rotary electric machine serves dual functions: generating electromagnetic force for motor operation and providing a mounting structure for the brake caliper. The outer periphery of the magnetic circuit unit acts as both a functional electromagnetic component and a structural support for the braking system, eliminating the need for separate fixing structures.
Solution Approach 2:
The fixing structure is merged with the magnetic circuit unit itself. The brake caliper is directly mounted on the outer periphery of the magnetic circuit unit, combining the electromagnetic component and the brake mounting function into a single integrated structure, thereby simplifying the overall fixing arrangement.
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 reduces the axial length of the vehicle wheel drive device, simplifies the fixing structure of the brake caliper, and enables suitable installation of the brake device within the in-wheel motor structure, improving overall efficiency and workability.
Implementation Method 1
a rotary electric machine that is received on a radially inner side of a vehicle wheel shaped in a cylindrical tubular form, wherein the rotary electric machine is configured to rotate the vehicle wheel
Implementation Method 2
a brake device that includes a brake disc and a brake caliper, wherein the brake device is configured to generate a braking force relative to the vehicle wheel
Data Source
AI summary
A vehicle wheel drive device includes: a rotary electric machine that is received on a radially inner side of a vehicle wheel shaped in a cylindrical tubular form and is configured to rotate the vehicle wheel; and a brake device that includes a brake disc and a brake caliper. The brake device is configured to generate a braking force relative to the vehicle wheel. The rotary electric machine includes a rotor and a stator which are opposed to each other in a radial direction. A hollow space is formed on a radially inner side of a magnetic circuit unit that is formed by the rotor and the stator. The brake device is placed in the hollow space in a state where the brake caliper is fixed to an axial end surface of the stator which faces in an axial direction, and the brake disc is rotatable integrally with the rotor.