Sauer danfoss 45 series KRL045 variable hydraulic pump

The KRL045 is a variable-displacement axial piston pump built on Danfoss's Series 45 open-circuit platform. It uses a tiltable swashplate design (Danfoss calls it a cradle swashplate) to vary output flow from zero up to maximum displacement, all while the input shaft spins at a constant speed. In practical terms, that means the pump only delivers the flow the system actually needs at any given moment — instead of running flat-out and dumping excess oil back to tank through a relief valve.

How the Pump Works

At a high level, the KRL045 operates like this:

1. Rotating group. A cylinder block containing multiple pistons rotates with the input shaft.

2. Swashplate angle. A hydraulic control piston sets the swashplate angle, and the pump uses a tiltable swashplate to vary displacement — steeper angle, more stroke per piston, more flow; flatten it out, and flow drops toward zero.

3. Compensator control. A built-in pressure compensator valve varies the swashplate angle from maximum to minimum position once the system reaches its set pressure, protecting the system from over-pressurization without needing a separate relief valve to do all the work.

4. Inlet and outlet flow. Fluid is drawn from the reservoir through the inlet line, passes through a screen that protects the pump from large contaminants, and the pump outlet feeds directional control valvessuch as PVG proportional valves or hydraulic integrated circuits (HICs).

This load-sensing, pressure-compensated behavior is what makes Series 45 pumps a good fit for machines with multiple, simultaneous, variable-flow functions — think an excavator running boom, stick, swing, and travel all at once, each demanding different flow at different times.

Control Options

Series 45 pumps, including the KRL045 frame, are available with a range of control types depending on the ordering code:

Pressure compensator (PC): limits maximum system pressure by de-stroking the pump

Load sensing (LS): matches pump flow to the highest-demand function in the circuit, improving efficiency

Electric proportional control: a proportional solenoid integrated into a remote pressure-compensated control, allowing the pump to operate at any pressure limit between the load-sense and pressure-compensation settings by varying solenoid current

Electronic Displacement Control (EDC) and Electronic Torque Limiting (ETL): more advanced electronic controls, <cite index="2-1">used to manage pump flow to machine functions, reduce dependency on intermediate valves, and protect against overload conditions

Common Applications

Because it sits in the mid-displacement range of the Series 45 family, the KRL045 shows up across a lot of mobile equipment categories:

Excavators and mini-excavators — powering swing, boom, and auxiliary circuits

Skid steer loaders — driving hydrostatic or auxiliary hydraulic functions

Paving machines and dozers — among the applications commonly listed for this pump family

Drilling equipment and mowers — again, named applications for the KRL045 frame

Agricultural and forestry machinery — related KRL frame sizes are used in similar duty cycles

For more information on the KRL045 hydraulic pump, please visit https://www.baolilaihydraulic.com/product/.

Specifications

Selection Table

Q1:What's the difference between KRL and KRR pumps?

A1: Both are Series 45 frames with very similar displacement, speed, and pressure ranges. The distinction generally comes down to rotation direction, port configuration, or specific frame variant — always check the full model code rather than assuming based on the prefix alone.

Q2: Is the KRL045 a fixed or variable displacement pump?

A2: It's a variable displacement pump. The swashplate angle adjusts continuously between zero and maximum displacement, based on the control type (pressure-compensated, load-sensing, or electronic), rather than delivering a constant flow per revolution.

Q3:How to purchase a KRL045 hydraulic pump?

A3: You can visit https://www.baolilaihydraulic.com/contact/ to contact us and purchase our products through various methods.

Q4:What is the price and delivery time of the KRL045 hydraulic pump?

A4: The specific price and delivery time will be provided based on the model you specify.