Hagglunds UK series Radial piston low-speed hydraulic motor

The UK series is a radial piston, low-speed, high-torque hydraulic motor built by Hägglunds — a Swedish brand that has been part of Bosch Rexroth since the early 2000s. It belongs to the Viking motor family, alongside sibling variants like the MK, MB, and UB, which share the same core radial piston architecture but differ in displacement, mounting style, or drive configuration.

Key Features and Benefits of the UK Series

Direct-Drive Simplicity

Because the motor bolts straight onto the driven shaft or is coupled through a torque arm, there's no intermediate gearbox to maintain, lubricate separately, or fail. Fewer components generally means fewer failure points and less downtime.

High Torque at Zero and Near-Zero Speed

The UK series can hold and develop full torque even when the shaft isn't turning — critical for winches under load, or machinery that needs to start moving heavy inertia from a dead stop.

Smooth, Controllable Rotation

Because multiple pistons are firing in sequence rather than a single power stroke, rotation is smooth even at very low rpm, without the speed pulsation you'd see in some other hydraulic motor types running near stall speed.

Bidirectional Operation

Reversing oil flow reverses the motor, making it well suited to applications like winches, capstans, and indexing tables that need to run both ways regularly.

Robust, Field-Serviceable Construction

Like other Hägglunds Viking-family motors, the UK series is built for harsh duty — marine environments, mining dust, offshore salt exposure — with piston assemblies and bearings designed for long service intervals and, where needed, in-field rebuild.

Freewheeling Capability

Many Hägglunds radial piston motors, including Viking-family units, can be configured to freewheel by disengaging the pistons from the cam track, allowing the rotating group to spin without generating flow resistance — useful in applications like paying out a winch line under a suspended load.

Common Applications

Marine Winches and Mooring Systems

This is the archetypal Hägglunds Viking-family application. On a ship's deck, a winch needs to hold a taut line under heavy load, pay it out under control, and haul it back in — all without the shock-loading risk of a geared electric drive. The UK series and its siblings were built with exactly this duty cycle in mind.

Anchor Handling and Towing Equipment

Similar demands apply on anchor-handling vessels and tugs, where torque control at very low or zero speed directly affects crew safety and equipment longevity.

Mining and Mineral Processing

Conveyor drives, mill drives, and crusher feed systems benefit from the same direct-drive, high-torque characteristics, especially where dusty or corrosive environments make gearbox maintenance a headache.

Pulp and Paper Machinery

Rewinders, unwinders, and other tensioned-web equipment need precise torque control across a wide speed range — another classic Hägglunds Viking-family niche.

General Industrial Direct Drives

Anywhere a designer wants to eliminate a reduction gearbox — turntables, indexers, positioners, and heavy rotating fixtures — a radial piston motor like the UK series is a candidate worth evaluating.

Installation and Maintenance Considerations

Charge pressure matters. Radial piston motors typically require a minimum charge (case or low-pressure port) pressure to keep the piston assemblies properly lubricated and to prevent cavitation, particularly during braking or overrunning conditions. Undersizing the charge circuit is one of the most common causes of premature wear on this motor family.

Oil cleanliness is non-negotiable. Like any precision hydraulic component, radial piston motors are sensitive to particulate contamination. Filtration specifications should be followed closely, and oil condition monitored, especially in dusty or marine environments.

Case drain flow and cooling. High-efficiency motors like these generate heat proportional to internal losses; adequate case flushing and cooling keep viscosity — and therefore motor life — in the expected range.

Mounting and torque arm alignment. Whether flange-mounted or shaft-mounted with a torque arm, correct alignment avoids introducing side loads the motor wasn't designed to absorb.

For more information on the UK hydraulic motor, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Q1: What's the difference between a radial piston motor and an axial piston motor?

A1: In a radial piston motor, pistons are arranged around the shaft and push outward against a cam ring, which suits very low-speed, high-torque, direct-drive duty. Axial piston motors have pistons arranged parallel to the shaft and are generally better suited to higher-speed, lower-torque applications, often paired with a reduction gearbox.

Q2: What causes premature wear in this motor family?

A2: The most common culprits are inadequate charge pressure, oil contamination, insufficient cooling/flushing, and misalignment at the mounting or torque arm. Following the manufacturer's charge pressure and filtration specifications closely will extend service life significantly.

Q3: What is the price and delivery time of the UK hydraulic motor?

A3: The price and delivery time will be provided based on the model you specify.

Q4:How to purchase a UK hydraulic motor?

A4: You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products via various methods.