variable displacement hydraulic pump animation brands

The displacement of a pump is defined by the volume of fluid that the gears, vanes or pistons will pump in one rotation. If a pump has a capacity of 30 cm3, it should treat 30 ml of fluid in one rotation.

In axial piston variable pumps, the flow is proportional to the drive speed and the displacement. The flow can be steplessly changed by adjusting the swivel angle. Axial piston variable ...

... axial piston pump type V60N is designed for open circuits in mobile hydraulics and operate according to the swash plate principle. They are available with the option of a thru-shaft for operating additional ...

Variable displacement axial piston pumps operate according to the bent axis principle. They adjust the geometric output volume from maximum to zero. As a result they vary the flow rate ...

... piston pump type V30D is designed for open circuits in industrial hydraulics and operate according to the swash plate principle. They are available with the option of a thru-shaft for operating additional ...

... circuit axial piston pumps are used as hydrostatic transmission components in self-propelled machines and for rotary drives in both fixed and mobile equipment of all kinds.

Axial piston twin flow pump. With a very high performance in all job conditions. Due to its twin flow configuration this pump allows a great variety of solutions in different job applications.

Air hydraulic pump, double pneumatic motor, double effect, foot operated with lock-up function, lever distributor valve (4/3), 10L tank, oil flow 8.5 / 0.26 l / min

... customer system options for mechanical, hydraulic and electric input solutions are available. Further special regulating features like torque control and pressure cut-off are also available. The reliable ...

... needs of truck hydraulics, the TXV variable displacement pumps with LS (Load Sensing) control allow flow regulation to suit the application requirements. The pump ...

... rev. displacements, these pumps are designed to operate in both directions of rotation (clockwise or counter-clockwise). Only one reference regardless of direction of rotation. The TXV indexable pumps ...

... PVG is a variable-displacement axial-piston pump designed to take on your most demanding applications. It offers high-pressure, superior performance in a compact design ...

Variable displacement pumps in closed loop; 3 basic design units and 8 max. displacement sizes of 14, 18, 21, 28, 35, 46, 56, 64 cc/rev; various control options; max. ...

Parker P2/P3 High Pressure Axial Piston Pumps are variable displacement, swashplate piston pumps designed for operation in open circuit, mobile hydraulic ...

... Series pump offers variable displacement axial piston pumps for open-circuit applications. Featuring a compact footprint and continuous operating pressure ...

Designed for closed-circuit applications, C Series Variable Displacement Axial Piston Pumps boost reliability and uptime. They feature a rugged design, wide range of controls and proven protection from pressure overloads for increased performance, all while maintaining a small footprint for added flexibility. The C Series adds further versatility with multiple displacement options and the ability to perform with a variety of control options.

In an axial-piston pump, the pistons and cylinder rotate around the center, longitudinal axis. The pistons and shoes move in and out of the cylinder because they are sliding upon a stationary, variable angle, swashblock.

Another option is to utilize a load sense compensator. With a load sense compensator, this compensator will include a lighter spring setting to control the swash plate. Upstream pressure is ported into a load sense port on the pump, as the pressure requirement increases, the pressure acts against the load sense piston. Once the pressure requirement is higher than the offset, the pump swash plate angle changes and the pump begins to increase flow, by increasing the swash plate angle, until we have enough pressure to balance the piston. Once balanced, the flow remains steady until the load changes.

The offset pressure is normally 200-300 PSI. With a load sense compensator, the pump produces what the load requires plus the spring offset, normally 200-300 PSI.

With a standard pressure compensator, you would have to set the pump at 2600 PSI to accomplish the work. When the work only requires 1500 PSI, the pump will be trying to produce 2600 PSI. Fifty percent of the time, your system will be operating at 1100 PSI of inefficiency, which means heat. With a load sense compensator, when the load requires 1500 PSI, the pump will actually produce about 17-1800 PSI. Yes, this is 300 PSI inefficient, but that is much better than 1100 PSI inefficient.

With a varying load, the load sense is a much better system. For additional control, you can utilize an electronic proportional flow control or throttle. You can use an electrical signal to vary the hydraulic signal which is received by the pump’s load sense line. This would give you full electronic control of the amount of flow the pump produces.

There are additional control options which allow you to remotely control the pressure compensator. With this remote compensator control, you can set 2 or more different system pressures. With the ability of a variable piston pump to build 5,000 or more PSI; the additional setting can be used when operating components with a much lower pressure requirement.

The next control is a torque limiting or HP limiting control. By adding an additional spring and piston, you can set a pump to always maximize its allowable input torque, therefore, maximizing output flow and pressure at a defined setting.

Our pump has an output of 15 CIR, a maximum flow of about 113 gallons at 1750 RPM. Our prime mover is an electric motor, 75HP with a 1.15 service factor. I want to keep my cylinder moving as fast as possible, but I also want to ensure that I never exceed a power demand 82 HP.

At 82 HP, the pump can produce 1254 PSI at full output, 113 GPM. As the load requires more pressure, the pump will begin to reduce flow and increase pressure. At 90 GPM flow, the system will produce about 1560 PSI; at 60 GPM we can get almost 2350 PSI. At 4500 PSI, the pump flow will be reduced to about 31 GPM. The advantage of this pump is that the internal controls of the pump are adjusting to maximize flow and pressure at all times without exceeding the available HP.

If I wanted to use a pump which could produce 113 gallons of flow at 4500 PSI, I would need 296 HP. If I choose a 75 HP motor with a pressure compensated variable piston pump, the motor would stall before the pressure compensator could kick in and reduce the pump flow. Depending on the load, a load sense pump could also stall the 75 HP motor if the load pressure is high enough to use up the HP before the pressure compensator kicks in. With a torque limiting (HP) control, we utilize the full limits of the prime mover and maximize power usage.

Piston design - Solid, hollow, or with piston rings. The design and weight of the pistons will have a major effect on pump efficiency. The Parker F11 design with its lightweight head and retained balls can reach significantly higher speeds than swashplate pumps with their longer, heavier pistons.

Some pumps and motors can run over-centre, which means they can provide flow or rotate their drive shaft in both directions. These are commonly used in closed circuit, mobile vehicle drives systems.

Bent axis designs tend to have much heavier duty shaft bearings than swashplate pumps. This is because they are more commonly used as motor drive units and have to take the wheel loads against their shaft. Swashplate pumps, on the other hand, tend to be driven through flexible couplings that will remove any side loads, so the internal bearing is sized just to take the internal loads from the dynamic and pressure loading forces.

Noise level can be an issue with piston pumps. The noise is generated by the discontinuities in the flow e.g. as the pistons move forward and backward they create a pulsating flow that passes into the complete hydraulic system and vibrates or radiates from other components further down the circuit. This flow discontinuity is further complicated by the supply port which connects and disconnects each piston as it rotates. The timing of the opening and closing can create other, higher frequency flow discontinuities. Often different timing plates are available for different operating conditions e.g. fixed speed or variable speed applications.

Case leakage line pressures are critical for controlling the pressure balance of the slipper against the suction pressure. Care should be taken with some pump controllers as the valves exhaust into the pump casing and can create dangerous pressure spikes. Make sure case drain lines are sufficiently sized. One possible solution may be to use a more compliant, clear plastic hose for the case leakage line which will have the effect of damping out these peaks before damage the slippers. Case leakage line temperatures are also a good way of monitoring the health of the pump as discussed in the vane pump section.

If you are in doubt about the most appropriate pump to use in your application then always talk to manufacture or distributor who should be able to offer the most appropriate pump range and advise the expected service life.

Piston pumps are durable and relatively simple devices. A basic piston pump is made up of a piston, a chamber, and two valves. The pump operates by driving the piston down into the chamber, thereby compressing the media inside. In a hand pump, this is usually air. Once the pressure of the air exceeds that of the outlet valve spring, the compressed media goes through the open outlet valve. When the piston is drawn back up, it opens the inlet valve and closes the outlet valve, thereby utilizing suction to draw in new media for compression.

Although somewhat expensive, piston pumps are among the most efficient types of pumps. They have an excellent pressure rating (as high as 10,000 psi), but their design makes them susceptible to contaminants. They provide an excellent solution for many high-pressure hydraulic oil pumping applications.

Axial piston pumps are positive displacement pumps that use multiple cylinders grouped around a central axis. The group of cylinders, usually containing an odd number, is called a cylinder block. The pistons within each cylinder are attached to a swashplate. The swashplate is also known as a cam or wobble plate and attaches to a rotating shaft. As the shaft turns, the angle of the swashplate changes, which drives the pistons in and out of their respective cylinders.

Since the swashplate is at an angle to the axis of rotation, the pistons must reciprocate axially as they orbit around the cylinder block axis. The axial motion of the pistons is sinusoidal. As a piston rises, it moves toward the valve plate. At this point in the rotation, the fluid trapped between the buried end of the piston and the valve plate is expelled to the pump"s discharge port through one of the valve plate"s semi-circular ports. As the piston moves back toward the valve plate, the fluid is pushed through the discharge port of the valve plate.

Axial piston pumps can be designed as variable displacement piston pumps, making them very useful for controlling the speeds of hydraulic motors and cylinders. In this design, a swashplate is used to vary the depth to which each piston extends into its cylinder as the pump rotates, affecting the volume of discharge. A pressure compensator piston is used in some designs to maintain a constant discharge pressure under varying loads. Cheaper pressure washers sometimes use fixed-rate designs.

In a typical pressure-compensated pump, the swashplate angle adjusts through the action of a valve using pressure feedback to make sure that the pump output flow is precisely enough to maintain a designated pressure. If the load flow increases, the pressure momentarily decreases, but the pressure-compensation valve senses the decrease and then increases the swashplate angle to increase the pump’s output flow, restoring the desired pressure.

Axial piston pumps can contain most of the necessary circuit controls intrinsically by controlling the swash-plate angle, to regulate flow and pressure. They are very reliable and can allow the rest of the hydraulic system to which they’re attached to be very simple and inexpensive.

They are used to power the hydraulic systems of jet aircrafts, being gear-driven off of the turbine engine"s main shaft, and are often used for automotive air conditioning compressors for cabin cooling. The design of these pumps meets the limited weight and space requirement in the vehicle"s engine bay and reduces vibrations.

Pressure washers also use these pumps, and axial reciprocating motors are used to power many machines. They operate on the same principles as axial piston pumps, except that the circulating fluid is provided under substantial pressure and the piston housing rotates and provides shaft power to another machine. A typical use of an axial reciprocating motor is powering small earthmoving machines such as skid loader machines.

This guide provides a basic understanding of axial piston pumps. To find out more about other types of pumps, read our guide here. For more information on related products, consult our other product guides or visit the Thomas Supplier Discovery Platform to locate potential sources or view details on specific products.