Under the harsh operating conditions of bridge cranes (overhead traveling cranes), frequent starts and stops, heavy-load lifting, and emergency braking impose continuous shocks on the transmission system. The conventional direct-drive motor-reducer configuration, lacking any buffering mechanism, is prone to causing... Large inrush current, premature fatigue and damage to transmission components (such as gears and bearings), and cracking of structural parts. and other issues that seriously affect equipment lifespan and operational safety.

Hydraulic Coupler As a “flexible link” for power transmission, it achieves non-rigid drive through the working oil medium, effectively isolating shocks and prolonging the startup process. It has become a key component in enhancing the reliability of modern bridge cranes. However, the full realization of its effectiveness depends on... Is the selection precisely matched to the equipment operating conditions? This article will systematically elaborate on the key considerations for selection, using ZTE’s hydraulic system as an example. YOXva650 The model is used as an example for application validation.

I. Core Principles and Adaptability Analysis for Bridge Cranes

The working principle of a hydraulic coupling is based on the combination of a centrifugal pump and a turbine. The motor drives... Pump impeller Rotation causes the working oil to gain kinetic energy under the action of centrifugal force, resulting in high-speed impact. Turbine The blades thereby drive the load. This process achieves a “softening” of power transmission.

For bridge cranes, Limited-torque hydraulic coupling Its value is particularly prominent:

Controllable soft start By precisely controlling the oil filling volume, the starting torque can be limited to a value within the motor’s rated torque. 1.35 to 1.5 times Avoid causing instantaneous overload impacts on the gearbox and steel structure.

Gentle start and stop process Its inherent slip characteristics can naturally extend the crane’s start-up acceleration process to... 22-30 seconds It greatly alleviates mechanical and electrical shocks.

Effective overload protection When the load increases abnormally (such as due to overload or jamming), the coupling slips, thereby isolating the impact and protecting the upstream motor and downstream transmission mechanism.

The Core Parameter Triangle for Selection Focus ：

Input speed and transmitted power It must be strictly matched with the rated speed and power of the drive motor.

Overload factor The starting overload factor (1.35–1.5 times) determines the smoothness of the start-up; the braking overload factor (2–2.3 times) determines the ability to handle sudden load changes.

Oil Filling Volume and Efficiency The oil filling amount directly determines the magnitude of the power actually transmitted (and must be adjusted within the allowable range for the model). Transmission efficiency ≥ 0.96 Ensured the economic efficiency of operational energy consumption.

II. Case Study: Selecting a Bridge Crane Based on the YOXva650 Model

With ZTE’s classic hydraulic products YOXva650 Limited-Torque Hydraulic Coupler As an example, let’s demonstrate how to perform the selection and verification for a bridge crane.

Step 1: Match power with rotational speed
Refer to the product parameter table; the power coverage range of YOXva650 is as follows:

Verification If the rated parameters of the drive motor for the trolley or hoist mechanism of the target crane are: 315 kW / 1500 rpm Therefore, this power value (315 kW) falls entirely within the power range (260–480 kW) corresponding to the YOXva650’s rated speed. Initial match established. 。

Step 2: Verification of Key Parameters

Overload factor The starting overload factor for the YOXva650 is 1.35–1.5, and the braking overload factor is 2–2.3, meeting the requirements of bridge cranes for smooth starting and resistance to sudden impacts.

Oil filling quantity determined For the 315kW motor, the oil filling volume of the working cavity must be precisely adjusted to the corresponding power point—typically—as per the oil-filling characteristic curve or calculation table provided by the manufacturer. 26.6 - 48 liters within the specified range) to ensure that the output torque is precisely matched.

Installation Dimension Verification The product’s external dimensions (e.g., outer diameter D = φ760mm) and shaft hole dimensions (maximum input hole diameter φ150mm) must be verified to ensure mechanical compatibility with the motor shaft and the reducer input shaft.

Step 3: Consideration of Maintenance Convenience—Extended Rear Auxiliary Chamber Design
Adopted by YOXva650 Extended auxiliary cavity structure This is a design with great practical value. When it’s necessary to inspect or replace the coupler, No need to disassemble or move heavy motors or gearboxes. Simply by removing the intermediate elastic pin coupling, the entire hydraulic coupling can be lifted out. This greatly simplifies the on-site maintenance process and reduces both maintenance time and labor costs.

III. Summary of the Selection Process and Recommendations for Professional Support

To select a hydraulic coupling for an overhead crane, you can follow the systematic procedure below:

Collect parameters Clearly specify the rated power and speed of the drive motor, as well as the load characteristics of the mechanism (such as the magnitude of inertia and the start-stop frequency).

Preliminary model Based on the power and speed, select a model from the product series (such as the YOXva series) whose power range includes the motor power.

Detailed verification We have confirmed the applicability of the overload factor with the supplier’s technical team and calculated the specific oil filling quantity.

Mechanical verification Review the installation dimensions, shaft holes, and connection methods to ensure on-site installability.

Confirm service Understand product features (such as ease of maintenance design) and the manufacturer’s technical support capabilities.

IV. Technical Assurance: Rooted in 40 Years of Professional Expertise

As a pioneering manufacturer in China’s hydraulic transmission industry, ZTE Hydraulics boasts over 40 years of R&D and manufacturing experience. The company is not only... Guangdong Province Hydraulic Transmission Engineering Technology Research and Development Center The supporting institution sees its products widely used in port, mining, and metallurgical sectors—areas that demand extremely high reliability.

The YOXva series products from Selection of high-strength materials, specialized sealing techniques, and high-precision dynamic balancing tests. All products adhere to stringent corporate standards, ensuring long-term stable operation even in the high-frequency, heavy-load operating environment of bridge cranes.

Get precise selection support ：
If you're designing or upgrading the drive system for an overhead bridge crane, simply provide the motor parameters and operating condition description, and ZTE Hydraulics' expert technical team will deliver a complete solution for you. Selection Calculation, Dimension Verification, and Commissioning Guidance Integrated solution.