Description
Detailed description of the automotive brake master cylinder 47201-3D470
1. Core Definition and Functions
Part Name: Brake Master Cylinder (Brake Master Cylinder)
Part Number: 47201-3D470
Core function: As the "heart" of the automotive hydraulic braking system, it converts the mechanical force exerted by the driver when stepping on the brake pedal into hydraulic pressure through the transmission of brake fluid, and drives the brake calipers (calipers) of the four wheels to clamp the brake discs, thereby generating braking force.
Compatible brand: This is the original part number of the Nissan-Renault Alliance.
Working philosophy: Adopt a series dual-loop system (usually in an X-shaped layout). That is, one pump is responsible for braking the two diagonal wheels (such as left front - right rear). When any circuit leaks and fails, the other circuit can still provide 50% of the braking force to ensure the vehicle can stop safely. This is the most fundamental safety design.
2. Detailed structural and material analysis
This is a precise aluminum casting component, and its main components and materials are as follows:
Component name, main material, function and characteristic description
The main pump body is made of high-strength aluminum alloy through die-casting, featuring a sturdy structure and lightweight design. There are two precise piston chambers inside. The surface is usually treated with anodizing to resist the corrosion of brake fluid and the erosion of external water vapor.
The first and second pistons are made of phenolic resin or special engineering plastics, which are lightweight, wear-resistant and have good compatibility with brake fluid. The main and auxiliary cups are installed on the two pistons to ensure the sealing of the chamber.
The core of the sealing assembly (rubber cup) is made of epichlorohydrin rubber or nitrile rubber. It features excellent resistance to brake fluid (DOT3/DOT4), high elasticity, resistance to high and low temperatures (-40°C to over 120°C), and anti-aging capabilities, ensuring long-term reliable sealing.
The fluid reservoir (oil can) is made of polypropylene or nylon semi-transparent plastic, which is convenient for visual inspection of the brake fluid level. It is connected to the main pump body through a rubber sealing ring and is resistant to chemical corrosion.
The high-strength carbon steel push rod connects the brake pedal and the piston inside the master cylinder, precisely transmitting the pedal force. The surface has anti-rust treatment.
The sensor interface is connected to the brake fluid level sensor with engineering plastic/metal. When the level is too low, it triggers the instrument panel alarm light.
3. Brief description of Working principle
Step on the pedal: The pedal force pushes the first piston forward through the push rod.
Establishing pressure: The first piston compresses the brake fluid in its front chamber, generating hydraulic pressure, which is then transmitted through pipelines to (for example) the sub-pumps of the left front and right rear wheels.
Linkage the second piston: Meanwhile, the movement of the first piston pushes the second piston forward through the spring and hydraulic pressure, compressing the brake fluid in its front chamber and transmitting the pressure to another set of diagonally (right front and left rear) sub-pumps.
Release the pedal: The return spring pushes the piston back to its initial position, and the brake fluid flows back from the slave cylinder to the master cylinder, releasing the braking force.
