YWZ4-500/E121 Electro-hydraulic Drum Brakes

The YWZ4-500/E121 series electro-hydraulic drum brake is a heavy-duty, normally-closed braking device engineered for ultra-large-tonnage industrial equipment. It is exclusively matched with the E121 series electro-hydraulic thruster (e.g., ED121/6), delivering exceptional braking torque, reliable fail-safe performance, and automatic gap adjustment. Suitable for non-explosive general industrial environments such as large-scale cranes, heavy-duty conveyors, metallurgical rolling mills, and port bulk handling machinery, it ensures stable braking and precise positioning for high-load, high-intensity operations.

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Core Technical Specifications

Parameter	Standard Value	Notes
Rated Drum Diameter	500 mm	Optimized for large-load equipment drum dimensions
Rated Braking Torque	4000–8000 N·m	Adjustable via thruster thrust and spring preload; meets ultra-heavy load braking demands
Matching Thruster Model	E121 (e.g., ED121/6, YT1-125Z/10)	Electro-hydraulic thruster with rated thrust 12500 N
Brake Shoe Clearance	1.0–1.5 mm	Automatically balanced by precision mechanical gap adjuster
Friction Lining Material	Non-asbestos high-temperature wear-resistant composite	Friction coefficient ≥0.38; low fading (≤12% at 250℃); heat capacity ≥1.2 kJ/(kg·℃)
Working Voltage	380V/660V 3-phase AC	Compatible with industrial power grids; dual-voltage optional
Protection Class	IP54	Dustproof and water-resistant, adaptable to humid/dusty workshop environments
Working Temperature	-20℃ to +55℃	Stable performance under extreme temperature fluctuations
Lining Thickness (Original)	16 mm	Replace when worn to ≤3 mm; wear-resistant design extends service life
Weight (w/o Thruster)	~180 kg	Robust structure for heavy-duty operation; standardized mounting interfaces

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Key Structural & Functional Features

Heavy-Duty Fail-Safe Normally-Closed Mechanism

Spring-driven braking: High-strength disc springs provide constant, large clamping force when the thruster is de-energized, ensuring immediate emergency braking within ≤0.6 seconds on power loss or thruster failure-critical for ultra-heavy load equipment safety.

Electro-hydraulic release: The E121 thruster generates high hydraulic pressure to push the brake arms, overcoming strong spring force and separating brake shoes from the drum smoothly, avoiding impact on equipment during startup.

Precision Automatic Gap Adjustment

Equipped with a multi-link interlocking gap balancing device that automatically compensates for the clearance between brake shoes and the drum caused by lining wear, maintaining the gap at 1.0–1.5 mm. Eliminates manual adjustment workload and ensures consistent braking torque even after long-term use.

Durable & Wear-Resistant Design

Clip-on thickened friction linings: 16 mm original thickness with high-temperature resistant and wear-resistant composite material, suitable for high-frequency braking scenarios; quick replacement without disassembling the entire brake body, reducing maintenance downtime.

Corrosion-resistant reinforcement: Brake body adopts shot blasting + anti-corrosion spraying treatment; fasteners are hot-dip galvanized or made of stainless steel; self-lubricating alloy bushings on brake arm hinges-resisting corrosion and reducing friction for extended service life.

Safety Interlock & Stability Enhancement

Configurable explosion-proof limit switch (optional): Sends real-time brake release/closure signals to the host control system, preventing equipment startup before full brake release and avoiding misoperation.

Reinforced brake arm structure: Adopts integral forging process, with tensile strength ≥600 MPa, ensuring no deformation under ultra-large braking torque; optimized stress distribution design reduces vibration and noise during braking.

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Working Principle

The brake operates in the spring braking + electro-hydraulic release mode, perfectly matching the E121 thruster's high-thrust performance:

Brake Release (Equipment Operation): When the host equipment starts, the E121 thruster is energized. Its motor drives the hydraulic pump to build high pressure, pushing the push rod to extend. The push rod acts on the reinforced brake arm, compressing the high-strength disc spring and separating the brake shoe from the drum-allowing the equipment to run smoothly.

Brake Application (Equipment Stop/Emergency): When the equipment stops, the thruster loses power. Hydraulic pressure dissipates rapidly, and the braking spring rebounds to pull the brake arm tightly, making the thickened friction lining clamp the drum evenly. The ultra-large braking torque quickly decelerates and stops the equipment, ensuring safe shutdown even under full-load conditions.

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Typical Applications

Widely used in non-explosive industrial environments requiring ultra-heavy load braking:

Large-tonnage overhead cranes, gantry cranes, and container cranes

Heavy-duty belt conveyors, bucket elevators, and bulk material handling equipment

Metallurgical equipment (e.g., blast furnace charging machines, rolling mill auxiliary systems)

Port bulk terminals and ship unloaders

Large-scale mining machinery and construction equipment

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Maintenance Guidelines

Daily Inspection (5–10 Minutes/Shift)

Check the integrity of the brake body, brake shoe, and lining: No cracks, deformation, or loose fasteners; replace lining immediately if thickness ≤3 mm.

Verify the automatic gap adjustment mechanism: Ensure flexible operation without jamming; check that the gap between shoe and drum is within 1.0–1.5 mm.

Inspect the matched E121 thruster: Check oil level, oil leakage, and cable connections; ensure no abnormal noise during operation.

Periodic Maintenance Schedule| Cycle | Core Tasks | Details & Standards ||-------|------------|---------------------|| 1 Month | Lubrication & Fastener Check | Apply lithium-based grease to brake arm hinges and bushings; re-tighten mounting bolts (torque: 45–55 N·m for M16 bolts). || 3 Months | Thruster Maintenance | Cooperate with E121 thruster maintenance: Replace hydraulic oil (ISO VG46), bleed air, and inspect seals for leakage. || 6 Months | Gap Adjuster & Spring Inspection | Clean and lubricate the automatic gap adjustment mechanism; check braking spring for fatigue (no deformation or cracks); replace spring set if elasticity decreases. || 12 Months | Comprehensive Performance Test | Conduct 1.2 times rated torque braking test; inspect drum runout (≤0.15 mm, re-machine if exceeding standard); check brake arm for deformation and repair if necessary. |

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Common Faults & Solutions

Fault Phenomenon	Possible Causes	Solutions
Brake cannot be released	Thruster oil shortage, motor failure, or hydraulic circuit blockage	Replenish ISO VG46 hydraulic oil; test thruster motor insulation (≥1 MΩ); clean hydraulic filter and pipeline.
Insufficient braking torque	Lining wear, gap adjuster failure, or spring fatigue	Replace friction lining; repair or replace gap adjustment device; replace braking spring set.
Abnormal noise during braking	Loose brake arm bolts, uneven lining wear, or drum deformation	Tighten bolts to specified torque; replace unevenly worn lining; re-machine drum if runout exceeds standard.
Slow brake response	Air in hydraulic system or worn thruster seals	Bleed air from the system by cycling the thruster 3–5 times; replace aging thruster seals.

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