Liquid-Cooled Disc Brake Segmented Design
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing liquid-cooled disc brakes face challenges in achieving optimal thermal performance for heavy vehicles, particularly in managing heat transfer to prevent coolant boiling and ensuring efficient cooling without excessive power loss or contamination, especially in constrained spaces with limited airflow.
Innovation Solution
A brake disc design featuring a thermally conductive outer surface for heat absorption during braking, a chamber for cooling liquid circulation, and a thermally insulative layer to control heat transfer, using materials like cast iron or aluminium for the outer surface and cooling plate, separated by a low-conductance gap to moderate heat transfer and prevent coolant boiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a monolithic metal disc is used for liquid-cooled braking, then heat transfer to coolant is efficient, but the disc surface temperature rises too quickly causing coolant boiling
Solution Approach 1:
The disc is segmented into two distinct portions: a friction portion (outer surface) and a cooling portion (inner surface), separated by a thermally insulative layer. This segmentation allows the friction surface to absorb braking heat while the insulative layer controls the rate of heat transfer to the coolant, preventing rapid temperature rise and coolant boiling.
Solution Approach 2:
A thermally insulative layer is introduced as an intermediary between the friction surface and the coolant chamber. This intermediate layer moderates the heat transfer process, allowing controlled thermal energy progression from the friction surface through the disc thickness to the coolant, preventing direct thermal shock and boiling.
2Productivity
If high thermal conductivity material is used throughout the disc, then heat dissipation is efficient, but the coolant temperature rises too quickly causing boiling
Solution Approach 1:
Different portions of the disc have different thermal properties: the friction portion uses materials with appropriate thermal conductivity for heat absorption, while the cooling portion near the coolant chamber uses materials with lower thermal conductivity to control heat transfer rate. This local differentiation ensures efficient heat dissipation without causing coolant temperature to rise too quickly.
3Volume of moving object
If a rotating disc design is used, then the brake can be compact, but rotary seals are required causing potential leakage
Solution Approach 1:
Instead of making the cooling chamber rotate with the disc (which would require rotary seals), the invention inverts the approach by making the friction surface rotate while the cooling chamber remains stationary. This allows coolant inlet and outlet connections to be fixed, eliminating the need for rotary seals and associated leakage problems.
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 design allows for efficient heat storage and dissipation, reducing the risk of coolant boiling and maintaining moderate liquid flow rates, while maintaining a stable thermal capacity to absorb braking heat without excessive temperature rise, as demonstrated by simulated temperature curves showing controlled cooling profiles.
Implementation Method 1
a thermally insulative layer between said first and second portions, for controlling the rate of heat transfer from said first portion to such cooling liquid
Implementation Method 2
the heated liquid and/or vapour exits through an outlet at the hub of the disc
Implementation Method 3
a first portion including an outer surface adapted to be in contact with friction material in order to brake a member with which said material or disc rotates
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A liquid-cooled brake disc comprises a central stationary aluminium cooling plate (14) with an internal chamber (17) for the circulation of water or other liquid coolant, and a series of cast iron sectors (20) mounted on opposite sides of the plate for contact by conventional brake friction material carried by discs on a shaft to be braked (not shown). The cooling plate (14) and sectors (20) are separated by thin air gaps (22) or other thermally insulative layers. In use the sectors (20) have sufficient thermal capacity to store the heat generated by a braking event over a relatively short period, and this heat is then transferred to the coolant over a relatively longer period at a rate determined by the conductance of the air gaps. In particular this form of construction can absorb and dissipate the heat of braking without bulk boiling of the coolant.