Eaton Vickers PVQ40 PVQ45 axial piston hydraulic pump

The PVQ line is a family of inline (swashplate-type) axial piston pumps originally developed by Vickers and now sold under the Eaton name after Eaton acquired Vickers in 1999. "PVQ" is the product family; the number that follows (40, 45) is the frame size, which corresponds roughly to nominal displacement in cubic centimeters per revolution.

Both pumps are variable displacement units. Instead of pushing a fixed volume every revolution, they adjust the angle of an internal swashplate so that flow matches what the system actually demands. That is the core reason they are popular in energy-conscious hydraulic circuits.

How the PVQ Pump Works

Understanding the mechanism makes troubleshooting far easier.

The rotating group and swashplate

A drive shaft turns a cylinder block containing an array of pistons. Each piston rides against a tilted swashplate through a slipper. As the block rotates, pistons are forced in and out of their bores, drawing fluid from the inlet port and pushing it out through the outlet. Increase the swashplate angle and the stroke gets longer, so flow goes up. Reduce the angle and flow falls toward zero.

The pressure compensator

The standard control is a pressure compensator. It is a spring-loaded spool that senses system pressure. While pressure sits below the compensator setting, the pump stays at maximum displacement. When pressure reaches the setting, the spool shifts and routes pressure to a stroking piston that pulls the swashplate back, so the pump delivers only the flow needed to hold that pressure.

The practical payoff is lower heat and lower power draw in holding phases. A fixed displacement pump would dump that excess flow over a relief valve and turn it into heat.

Load-sensing and other controls

Depending on the model code, a PVQ can also be configured with load-sensing, remote pressure control, or torque-limiting options. Load sensing lets the pump hold a fixed margin above the highest load pressure, which is a very efficient way to run a multi-function machine.

Where PVQ40 and PVQ45 Pumps Are Used

Example 1: Hydraulic press

A 200-ton forming press needs high flow during fast approach and nearly none during the dwell at tonnage. A PVQ45 on a pressure-compensated circuit delivers full flow for the approach, then destrokes to hold pressure with minimal heat. The shop saw oil temperatures drop noticeably compared with its older fixed-displacement setup.

Example 2: Injection molding machine

Molding cycles alternate between clamp, inject, hold, and cooling. A PVQ40 on a load-sensing control matches flow to each phase, saving electrical energy during the long cooling period.

Example 3: Machine tool clamping and feed

On a CNC machining center, a compact PVQ can supply both workholding pressure and feed axes, holding steady pressure without constant relief valve losses.

Example 4: Mobile and material handling equipment

PVQ pumps have also appeared on utility vehicles and handling equipment, though in newer mobile designs, purpose-built load-sensing pumps are more common.

Common Problems and How to Diagnose Them

Low or no flow

Check in this order: shaft rotation direction, coupling condition, inlet strainer and suction line, oil level, then compensator setting. A stuck compensator spool or a broken drive coupling can mimic a worn pump.

Pressure will not build

Rule out system leaks and relief valves first. Then look at the pump: excessive internal leakage from a worn rotating group or valve plate will show up as high case drain flow.

Excessive noise or whine

Usually cavitation (restricted inlet, cold or overly thick oil, clogged strainer) or aeration (loose suction fittings, low oil level, a failed shaft seal pulling air). Fix the root cause before replacing parts, or the new pump will fail the same way.

Overheating

High case drain flow converts leakage into heat. If oil temperature climbs while pump output declines, internal wear is the likely cause.

Using case drain flow as a health check

Measure case drain flow at operating temperature and pressure. A rising trend over months tells you the pump is wearing. Compare the number to Eaton's published guidance for your size, and record a baseline when the pump is new or freshly rebuilt.

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

Specifications

Selection Table

Q1: What is the difference between the Vickers PVQ40 and PVQ45?

A1: Both are variable displacement axial piston pumps in the same family. The PVQ45 is the slightly larger unit, so it moves a bit more flow per revolution. Controls, mounting, and construction vary with model code, so compare nameplates, not just names.

Q2: How do I know if my PVQ pump is worn out?

A2: The clearest signs are rising case drain flow, falling output at pressure, higher oil temperature, and increased noise. Measuring case drain flow against a baseline is the most reliable test.

Q3: How to purchase a PVQ hydraulic pump?

A3: 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 PVQ hydraulic pump?

A4: We will provide the price and delivery time based on the specific model you provide.