Multi-disc Brake Cooling via Variable Orifice Fluid Rail
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional multi-disc brake assemblies face challenges in efficiently dissipating heat generated during braking while minimizing wear and parasitic losses, often requiring excessive coolant flow which increases drag and reduces vehicle efficiency.
Innovation Solution
A liquid-cooled multi-disc brake assembly with a cooling system that delivers coolant fluid through a series of orifices of varying sizes connected to an axial fluid rail, ensuring appropriate heat removal at each interface without excess coolant, and a method for operating the vehicle that adjusts coolant flow based on braking events.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If excess coolant is used to achieve adequate cooling, then heat dissipation is improved, but drag losses and parasitic losses increase
Solution Approach 1:
The patent applies local quality by varying the orifice sizes at different axial positions along the fluid rail. The orifices are larger near the center of the disc pack where heat generation is highest, and smaller toward the ends where less cooling is needed. This localized differentiation of coolant flow rates optimizes heat dissipation efficiency while minimizing excessive coolant usage and associated drag losses.
Solution Approach 2:
The patent changes the parameter of orifice size along the axial direction of the fluid rail. By gradually varying the orifice diameter from center to ends, the system dynamically adjusts coolant flow distribution to match the thermal load distribution, achieving effective cooling with reduced overall coolant flow and minimized parasitic losses.
2Device complexity
If coolant flow is limited to minimize auxiliary hydraulics size, then system complexity is reduced, but cooling capacity is insufficient
Solution Approach 1:
The fluid rail incorporates orifices of varying sizes along its axial length, with larger orifices positioned where greater cooling is needed (near the center) and smaller orifices where less cooling is required (toward the ends). This local differentiation allows the system to achieve adequate cooling capacity with a limited overall coolant flow, thereby minimizing the size of auxiliary hydraulic components.
3Loss of energy
If brakes are run above oil level to minimize drag losses, then parasitic losses are reduced, but cooling efficiency decreases
Solution Approach 1:
The system performs preliminary cooling action by delivering coolant directly to the friction interfaces through the orifices in the fluid rail before the brakes are fully engaged or during intermittent operation. This proactive cooling approach allows the brakes to operate above the oil level with minimal drag losses while still maintaining adequate cooling through targeted coolant delivery to the hottest spots.
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 improves brake performance by maintaining efficient heat dissipation and reducing wear, allowing for increased braking power and extended service intervals while minimizing coolant demand and drag losses.
Implementation Method 1
The heat is removed by oil which is circulated to an oil-to-air cooler and the heat is then removed to the environment
Implementation Method 2
The power is usually converted to heat when the brake friction disks make contact with the reaction disks. The heat is removed by oil
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A multi-disc brake assembly comprising a disc pack may desirably be liquid cooled (i.e. is "wet") to dissipate the substantial heat generated from braking. In conventional assemblies, coolant fluid is generally delivered in a uniform manner to the discs in the disc pack. However, the heat distribution in the disc pack from braking is not uniform. But wear can be significantly increased where an inadequate amount of coolant is delivered, while drag can be increased unnecessarily where an excessive amount of coolant is delivered. In such an assembly, an improved coolant distribution can be obtained by appropriately varying the size of the numerous orifices which may be used to distribute coolant to the disc interfaces from an axial fluid rail provided in a rotating central shaft. Specifically, the orifices decrease in size from the middle to the ends of the disc pack.