Design of 20ton double girder end carriage suitable for bridge crane

(1) Structural design features
Compact and lightweight design
The European end beam adopts an optimized box beam structure (usually welded from steel plates), and the material is mostly high-strength steel (such as Q235B or Q345B), which reduces the deadweight while ensuring the bearing strength, and reduces the load on the plant structure.

Modular assembly
The end beam, main beam, and trolley drive system adopt standardized interface design, which is convenient for rapid installation and maintenance, and can also adapt to the needs of different spans.

Low clearance requirements
Through a compact drive layout (such as a built-in drive unit), the overall height of the end beam is reduced, saving vertical space in the plant.

(2) Features of the drive and travel system
Three-in-one drive unit
It adopts an integrated drive device that integrates motor, brake, and reducer (common brands such as SEW and Nord), with a compact structure, high transmission efficiency, and easy maintenance.

Double-wheel or four-wheel configuration

According to the wheel pressure calculation, the end beam of a 20-ton crane is usually equipped with double or four wheels (1 or 2 wheels on each side) to ensure uniform distribution of wheel pressure and reduce track wear.

The wheel is made of forged steel (such as 45# steel or 42CrMo), and the surface is high-frequency quenched, with a hardness of HRC45-55 and strong wear resistance.

Frequency conversion speed control
The trolley uses a frequency conversion motor to achieve stepless speed regulation and soft start/stop, stable operation, and reduced impact and shaking.

Bearings and wheel sets
Use spherical roller bearings to automatically compensate for installation errors; the wheel set design has an anti-derailment function to ensure the centering of the track.
(3) Safety and stability features
Buffer and anti-collision device
Polyurethane or hydraulic buffers are installed at both ends of the end beam to absorb collision energy and protect the crane and track.

Limit and protection
Set a travel limit switch to prevent the trolley from overtravel.

Anti-derailment devices (such as guide wheels or guardrails) prevent the wheels from leaving the track.

Torsional rigidity
The end beam and the main beam are rigidly connected by high-strength bolts to ensure the torsional performance of the overall structure and adapt to frequent start-stop and eccentric load conditions.