YWZ8-400/E121A Electro-hydraulic Drum Brakes

YWZ8-400/E121A Electro-hydraulic drum brakes

The YWZ8-400/E121A is a robust, industrial-grade electro-hydraulic drum brake widely used for deceleration and parking (holding) braking in heavy-duty machinery. It combines the reliable YWZ8 series brake frame with a powerful electro-hydraulic thruster to provide smooth, fail-safe braking performance.

The model number breakdown is as follows:

YWZ8: The series designation for a standard electro-hydraulic drum brake (compliant with JB/ZQ4388 installation dimensions).

400: Indicates the Brake Wheel Diameter of 400 mm.

E121: Indicates it is matched with an Ed121 electro-hydraulic thruster, which provides a rated thrust force of 12,100 N (approx. 1.2 tons).

A: Typically represents a specific structural variant, customized mounting configuration, or a specific manufacturer's suffix.

1.Structure Composition

E121A Electro-hydraulic Thruster: Core actuating component; energized to extend pushrod for brake releasing, internal reset spring retracts rod after power loss.

High-rigidity cast steel brake pedestal: Integral casting structure with strong anti-deformation and anti-vibration capacity for long-term heavy-load service.

Double symmetric brake shoe assembly: Hinged swing brake shoes mounted with replaceable friction linings; worn pads can be changed individually without disassembling the whole brake.

Main compression braking springs: Provide permanent clamping force to press brake shoes onto drum surface for parking & emergency braking.

Clearance fine-tuning mechanism: External adjusting screw for convenient lining-drum gap calibration to compensate lining abrasion.

Optional accessories: Manual release device, lining wear limit switch, travel monitoring sensor.

2. Working Principle (Fail-Safe Normally Closed)

Power-off Braking (Standby/Parking): When the equipment stops or power fails, E121A thruster cuts off power, hydraulic pressure inside thruster disappears and pushrod retracts. The preloaded main braking springs pull the linkage and force two brake shoes to tightly grip the 400mm brake drum; friction torque locks drum rotation and prevents accidental load slipping.

Power-on Release (Machine Running): After switching on power supply, E121A internal motor drives hydraulic pump to build oil pressure, pushrod stretches out and pushes the brake linkage to overcome spring preload. Two brake shoes separate from brake drum surface; the brake drum rotates freely together with hoisting mechanism.

Emergency Braking: Sudden power failure or control breakdown instantly triggers automatic spring clamping to lock drum for equipment and load safety.

3. Key Advantages

Optimized YWZ8 linkage structure: More compact layout than conventional YWZ4 type, saves installation space for compact-designed hoisting machines.

Stable & smooth braking performance: Optimized lever ratio reduces braking impact, effectively avoids load swinging during stopping; high-temperature resistant friction linings resist heat fading under continuous frequent braking.

Easy maintenance: Separable friction pads and external gap adjustment shorten daily inspection and replacement downtime.

Reliable fail-safety: Full spring-driven braking independent of electric/hydraulic power, conforms to international hoisting machinery safety specifications.

Good environmental adaptability: Sealed thruster and paint-coated brake frame effectively resist dust, splash water and moderate corrosive workshop atmosphere.

4. Application Range

General industrial overhead cranes, gantry cranes, workshop single/double girder cranes

Metallurgy, building material, logistics yard fixed winches and hoisting equipment

Port small lifting machinery, mine non-explosion conventional hoist devices

Material handling conveyor drum safety braking

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