SINOTRUK HOWO Beam Pin 70×205

Description

The working principle of the Beam Pin 70×205:

1. The Basic Structure of Beam Pin:
Main material: Usually made of high-strength alloy steel (such as 40Cr, 42CrMo, etc.), after quenching and tempering treatment, it has high hardness and wear resistance.
Components: Include the pin body, lubrication hole, sealing ring (or dust cover), fixed spring clip (or bolt), etc. The balance beam pin of some heavy-duty trailers may have a bushing (copper bushing or nylon bushing) to reduce friction.

2.The Working Principle of Beam Pin:
The balance beam pin is connected to the balance beam and the axle (or frame) by a hinged method. When the trailer travels over uneven roads, the balance beam swings around the pin body, allowing the load of each axle to be evenly distributed, avoiding single-axis overload, and buffering road impacts to ensure driving stability.

Beam Pin 70×205 Main functions:

Load balancing: Coordinating the vertical loads of each axle of the multi-axle trailer to prevent any single axle from bearing excessive force, thereby extending the lifespan of the tires and axles.
Shock absorption and buffering: Absorbing road vibrations through the swinging of the balance beam, reducing the jolting of the trailer and protecting the cargo and chassis components.
Guidance and support: Providing a rotational fulcrum for the balance beam to ensure that the axles maintain the correct driving direction as the road surface undulates.

Beam Pin 70×205 Common Faults and Causes

1. Wear or fracture of the pin
Symptoms: The balance beam shows increased swing gap, and abnormal noises occur during driving; severely, the pin breaks, causing the axle to shift.
Causes:
Long-term overloading or poor road conditions result in excessive alternating load on the pin;
Lack of lubrication intensifies the dry friction between the pin and the bushing, leading to accelerated wear;
Poor material or heat treatment process results in insufficient fatigue resistance.

2. Failure of lubrication and rusting
Symptoms: The rotation resistance of the balance beam increases, and it gets stuck during shifting or bumping; rust appears on the surface of the pin.
Causes:
Failure to add lubricating grease at regular intervals or clogged lubrication holes;
Damaged sealing ring, allowing rainwater and dust to enter the gap of the pin, causing rust.

3. Loose fixed components
Symptoms: The balance beam shakes abnormally, the pin axially moves, and there may be detachment of bolts / spring clips.
Causes:
Lack of proper tightening of bolts or failure of anti-loosening measures;
Long-term vibration causes fatigue deformation of spring clips, losing their fixation function.

Beam Pin 70×205 Maintenance and Replacement Key Points：

1. Daily Inspection
Inspection Frequency: Every 5000-10000 kilometers of travel or once a month.
Inspection Contents:
Visual inspection of the pin body and bushing for cracks and wear marks;
Shake the balance beam and check the pin body clearance (normal clearance ≤ 0.5mm, more than 1mm requires adjustment or replacement);
Check if the lubrication holes are unobstructed and if the sealing rings are aged or damaged.

2. Lubrication Maintenance
Lubrication Cycle: Every 1-20000 kilometers or once a quarter. In harsh conditions (such as heavy loads, muddy roads), the cycle should be shortened. Operation steps:
Use the grease gun to inject lithium-based lubricating grease (NLGI 2 grade) into the lubrication holes until the old grease is squeezed out from the gaps;
Clean the oil stains on the pin body surface and replace the damaged dust cover.