YT1-90Z/6 Series Electro Hydraulic Thrusters

The YT1 series electro-hydraulic thruster is a widely used linear actuator integrating an AC motor, centrifugal pump, and hydraulic cylinder. It is mainly paired with drum brakes, disc brakes, and rail clamps for industrial equipment such as cranes, conveyors, and hoists. It adopts a spring-return, hydraulic-drive working mode, featuring stable thrust, low noise, and fail-safe performance. Below is a detailed overview of its core parameters, structural features, working principle, common faults, and maintenance guidelines.

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Core Technical Parameters (Typical Models)

The YT1 series has multiple models classified by thrust and stroke (e.g., YT1-25Z/4, YT1-45Z/5, YT1-90Z/8). The following are the general technical specifications of the series:

Parameter	General Specification
Rated Thrust Range	250–12,500 N
Rated Stroke Range	40–120 mm
Motor Power	0.09–1.5 kW (3-phase AC 380V, 50Hz; single-phase AC 220V optional)
Duty Cycle	S3-25%/40%/60% (suitable for intermittent operation)
Hydraulic Oil Type	ISO VG32/46 hydraulic oil (low-temperature resistant oil optional for -25℃ environments)
Oil Capacity	0.2–2.5 L (varies by model)
Protection Class	IP54/IP55 (motor housing; IP65 optional for outdoor use)
Working Temperature	-25℃ to +50℃
Weight	8–65 kg (varies by model)
Compliance Standard	JB/T 10603-2006

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Key Structural Features

Integrated Compact Design

Combines motor, pump, and cylinder into a single unit, with no external hydraulic pipelines, saving installation space and reducing oil leakage risks.

Equipped with a transparent oil level gauge and drain plug for easy oil level checking and replacement.

Fail-Safe Spring Return Mechanism

When powered on, the motor drives the pump to generate hydraulic pressure, pushing the push rod to extend and release the brake.

When powered off, the internal return spring drives the push rod to retract, enabling the brake to clamp automatically, ensuring equipment safety during power outages.

Adjustable Thrust & Stroke

The thrust can be adjusted by modifying the spring preload; the stroke can be fine-tuned via the limit nut on the push rod to match the brake's release requirements.

Corrosion & Dust Resistance

The motor housing uses a sealed structure; fasteners are galvanized or treated with anti-corrosion coating, suitable for dusty, humid industrial environments.

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Working Principle

The YT1 series operates on a hydraulic drive, spring return principle, matching the normally-closed brake's working logic:

Release State (Power-On)

When the motor is energized, it drives the centrifugal pump to rotate, pressurizing the hydraulic oil in the chamber. The high-pressure oil pushes the piston and push rod outward, compressing the brake's braking spring and achieving brake release.

Braking State (Power-Off)

When the power is cut off, the pump stops working, and the hydraulic pressure disappears. The thruster's internal return spring and the brake's braking spring drive the push rod to retract, making the brake clamp the wheel/drum to achieve braking.

Speed Regulation

The extension/retraction speed of the push rod can be adjusted by installing a throttle valve on the oil circuit to meet the brake's response speed requirements.

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Typical Applications

Crane Equipment: Paired with YWZ series drum brakes for lifting and traveling mechanism braking of overhead cranes, gantry cranes, and port cranes.

Conveying Machinery: Used for belt conveyor belt tensioning and emergency braking systems.

Mining & Metallurgical Equipment: Matched with heavy-duty brakes for mine hoists, blast furnace charging machines, and other high-load equipment.

Rail Clamps: Coordinated with YFX series wind-resistant wedge brakes to provide release power for rail clamping devices.

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Common Faults & Solutions

Fault Phenomenon	Possible Causes	Step-by-Step Solutions	Preventive Measures
Push rod fails to extend	1. Low oil level or oil leakage2. Motor burnout or power supply failure3. Pump impeller blockage or wear4. Piston jamming	1. Refill hydraulic oil; replace damaged seals2. Check power supply; test motor insulation resistance (≥1 MΩ); replace motor if faulty3. Disassemble the pump, clean the impeller, and replace it if worn4. Disassemble the cylinder, clean the piston and inner wall, and apply hydraulic oil for lubrication	- Check oil level daily; replace oil every 6 months- Protect motor cables from damage; ground the motor reliably
Insufficient thrust, slow extension	1. Air trapped in the oil circuit2. Hydraulic oil contamination or viscosity mismatch3. Return spring fatigue4. Impeller wear reduces oil pressure	1. Bleed the system (power on/off 3–5 times to expel air)2. Drain contaminated oil; refill with ISO VG32/46 oil3. Replace the return spring set4. Replace the worn impeller	- Bleed air after oil replacement- Use clean, brand-consistent hydraulic oil
Push rod fails to retract or reset slowly	1. Piston stuck due to oil contamination2. Return spring deformation or breakage3. Throttle valve adjustment improper4. Seal damage causes oil backflow	1. Clean the piston and cylinder; replace the seal2. Replace the return spring3. Adjust the throttle valve to increase retraction speed4. Check and replace damaged O-rings and oil seals	- Clean the oil filter quarterly- Avoid over-tightening the throttle valve
Motor overheating	1. Exceeding the rated duty cycle (e.g., S3-60% used for continuous operation)2. Clogged motor ventilation holes3. Voltage fluctuation (deviation >±10%)	1. Reduce operation frequency; extend interval between cycles2. Clean dust on the motor housing and ventilation holes3. Stabilize the power supply voltage	- Monitor motor surface temperature (≤60℃)- Clean motor ventilation holes monthly
Oil leakage	1. Oil seal aging or damage at the push rod2. Loose end cover bolts or damaged O-rings3. Cylinder body crack (rare, caused by collision)	1. Replace the push rod oil seal; lubricate the seal with oil before installation2. Re-tighten end cover bolts; replace damaged O-rings3. Repair or replace the cylinder body if cracked	- Replace seals every 12 months- Avoid collision and impact on the thruster

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Maintenance Guidelines

Daily Inspection (5–10 Minutes/Shift)

Check the oil level: Ensure it is between the MAX and MIN marks of the oil gauge; refill if insufficient.

Check for oil leakage: Inspect the push rod, end cover, and drain plug for dripping oil.

Manual test: Push/pull the push rod to confirm smooth movement without jamming.

Electrical check: Inspect motor cables and terminals for fraying or loosening; confirm no abnormal noise when powered on.

Periodic Maintenance Schedule| Cycle | Core Tasks | Details & Standards || :--- | :--- | :--- || 1 Month | Lubrication & Fastener Check | - Apply a thin layer of lithium-based grease to the push rod and limit nut- Re-tighten mounting bolts (torque: 20–30 N·m for M6–M8 bolts) || 3 Months | Oil Replacement & System Bleeding | - Drain old oil; flush the oil chamber with clean oil- Refill with ISO VG32/46 oil; bleed air by powering on/off 3–5 times- Inspect oil seals and O-rings for aging || 6 Months | Pump & Motor Overhaul | - Disassemble the pump; clean the impeller and filter screen- Check motor bearings for wear; replace if rotation is noisy- Test motor insulation resistance (≥1 MΩ at room temperature) || 12 Months | Comprehensive Overhaul | - Replace return springs, oil seals, and O-rings- Clean the piston and cylinder inner wall; remove rust or carbon deposits- Calibrate thrust and stroke to match the brake's requirements |

Special Environment Maintenance

High-Dust Environments: Install a dust cover on the push rod and motor ventilation holes; shorten oil replacement cycles to 2 months.

Low-Temperature Environments (-25℃ to 0℃): Use low-temperature hydraulic oil (ISO VG22); preheat the thruster for 5–10 minutes before operation.

Coastal Salt-Fog Environments: Apply anti-rust oil to the thruster body monthly; use stainless steel fasteners to prevent corrosion.

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Safety Precautions

Lockout-Tagout Before Maintenance: Cut off the power supply and hang a warning sign to prevent accidental startup.

No Mixed Oil Use: Do not mix different brands or types of hydraulic oil to avoid seal damage and system failure.

Avoid Overload Operation: Do not exceed the rated thrust and stroke; this will cause permanent damage to the pump and spring.

Grounding Protection: Ensure the motor is reliably grounded to prevent electric shock hazards.

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