# Axial Piston Pumps Equation Help

In summary, the conversation discusses the design of an axial piston pump and the formula for power output. The formula includes variables for power, radius, piston area, number of pistons, swashplate angle, pressure differential, and either rpm or revs per second. The formula needs to be converted to metric units, and the person asks for confirmation on the correct units. They also inquire about any resources for pump design and suggest deriving the formula for oneself as a good starting point.

Right, I am in the process of designing an axial piston pump.

I have obtained the following formula from a textbook for power output. unfortunately i don't know what units the formula requires, is anyone able to confirm what they are? Also, if anyone knows of a good resource for pump design please let me know!

right

P=2rANtan@(p2-p1)n

where

P=power
r=radius of centre of piston from axis
A=area of piston
N=number of pistons
@=swashplate angle
p2 and p1 = pressure differential
n=either rpm or revs per second - i don't know

I need the forumla to be in metric form - basically, if i use

P=Watts
r=metres
A=metres^2
p=pascals
n=rpm/rps

Will the formula be correct?

Many Thanks

Ed

Have you tried deriving it for yourself? This is always a good start.

At the very least, you should be able to check the units.

## 1. What is the equation for calculating the displacement of an axial piston pump?

The equation for calculating the displacement of an axial piston pump is:
Displacement (in^3/rev) = Number of pistons x Piston area x Stroke length x Number of pistons in each cylinder x Number of cylinders

## 2. How do I determine the flow rate of an axial piston pump?

The flow rate of an axial piston pump can be determined by using the equation:
Flow rate (gpm) = Displacement (in^3/rev) x Speed (rev/min) / 231

## 3. Can the efficiency of an axial piston pump be calculated using an equation?

Yes, the efficiency of an axial piston pump can be calculated using the equation:
Efficiency (%) = Actual flow rate (gpm) x Actual pressure (psi) / Theoretical flow rate (gpm) x Theoretical pressure (psi)

## 4. What is the relationship between pressure and torque in an axial piston pump?

The relationship between pressure and torque in an axial piston pump is directly proportional. This means that as pressure increases, torque also increases.

## 5. How does the number of pistons and their size affect the performance of an axial piston pump?

The number of pistons and their size directly affect the displacement and flow rate of an axial piston pump. More pistons can increase the displacement, while larger pistons can increase the flow rate. Additionally, a larger number of pistons can provide smoother operation and reduce noise levels.