Drivaxlar för MHC-underrede

The Suspension Challenge: Why Standard Shafts Fail on MHCs

The Mobile Harbor Crane (MHC) is a marvel of engineering, combining the mobility of a vehicle with the lifting capacity of a stationary crane. Models like the Liebherr LHM 550 eller den Konecranes Gottwald Model 6 rely on complex undercarriages featuring 10 to 20+ axle sets to distribute their immense weight (often exceeding 400 tons) over the quayside. The defining feature of these chassis is the Hydraulic Suspension System. To ensure equal wheel load distribution on uneven port surfaces—typical of the settling reclaimed land in areas like Maasvlakte II or the historic quays of Amsterdam—each axle set can vertically travel up to ±300mm.

This vertical travel creates a geometric nightmare for the drive shaft. The hydraulic travel motor is typically rigidly mounted to the chassis frame, while the wheel hub or differential moves with the axle. As the suspension cycles from fully compressed to fully extended (or when lifting the crane on outriggers), the operating angle of the connecting drive shaft changes drastically, often exceeding 15 or even 20 degrees. Standard industrial cardan shafts are generally designed for angles up to 10 degrees. When forced beyond this limit, they experience “binding” or “gimbal lock,” generating massive oscillating forces that shatter cross bearings and shear flange bolts.

Ever-Power addresses this specific failure mode with our “Series-MHC-Wide” drive shafts. These are not off-the-shelf industrial parts; they are purpose-built powertrain components featuring high-angle yoke geometries and extended telescopic spline sections. By utilizing a compact double-cardan design or a specialized wide-angle single joint, we ensure smooth constant-velocity torque transmission even when the chassis is in its most extreme articulation position, such as when “crabbing” (diagonal steering) over rail tracks or drainage channels.

Technical Specifications: MHC Axle Drive Series

The following specifications apply to our aftermarket replacement shafts for major MHC brands. We specialize in retrofitting older cranes where OEM parts are obsolete or have excessive lead times.

Case Study: Retrofit at a Multi-Purpose Terminal in Rotterdam

Utmaningen: A busy terminal in the Waalhaven district operating two Liebherr LHM 400 cranes faced a persistent issue. The drive shafts connecting the hydraulic motors to the steering axle sets were failing prematurely—specifically, the cross bearings were shattering. The terminal floor had significant gradients due to settling, causing the suspension to work aggressively. The OEM shafts, designed for flatter surfaces, could not handle the combination of high torque and the 18-degree angles experienced during sharp maneuvering.

Lösningen för ständig kraft: We dispatched our application engineers to measure the suspension geometry dynamically.

1. Design: We proposed a “Series-MHC-Pro” shaft utilizing a Double Cardan joint at the motor end. This design splits the angle between two joints, effectively halving the operating angle per cross and canceling out velocity fluctuations.

2. Material: We upgraded the flange material to 42CrMo4 to prevent bolt hole elongation, a common issue observed on the client’s old shafts.

3. Logistics: The complete batch of 12 shafts was manufactured and delivered within 18 days.

Resultatet: Since the retrofit 24 months ago, the cranes have required zero driveline maintenance beyond routine greasing. The operator reported smoother steering response and reduced vibration in the chassis.

Factory Customization: Rapid Response for Breakdown Logistics

In the port industry, a crane that cannot move is a crane that cannot earn. We understand that waiting 12 weeks for an OEM replacement part from Germany or Finland is often not an option. Ever-Power’s manufacturing strategy is built on Rörlighet.

We maintain a strategic stock of “semi-finished” wide-angle yokes and spline shafts compatible with Liebherr and Gottwald interfaces. This allows us to cut, weld, balance, and paint a custom-length replacement shaft within 72 hours. Our facility near Hangzhou is optimized for air-freight logistics, meaning we can have a critical undercarriage shaft on your desk in the Netherlands in less than a week. We don’t just supply parts; we supply operational continuity.