Swash Plate Pump – Parts, Working, Advantages, and Disadvantages

Swash Plate Pump is a positive displacement pump that consists of a combination of a piston and cylinder and a swash plate.

A Swash Plate is used inside this pump so it is named a swash plate pump. A swash plate is a slanted disc that is present inside this pump.
The swash plate is also known as a cam or wobble plate.

Its full name is the swash plate axial piston pump.

It is a variable displacement pump I.e the flow quantity of this pump can be increased or decreased according to the requirement.

Swash Plate Pump has various manufacturing applications and is also used in automobiles for various purposes.

Parts Of Swash Plate Axial Piston Pump:

1) Drive Shaft:
Drive Shaft is a rotating element that rotates using the power of the motor. The cylinder block is mounted on this drive shaft.
2) Electric Motor:
Electric Motor is used to rotate the driving shaft due to which the cylinders of the axial piston pump rotate.
The motor is connected to the driving shaft using a coupling.
2) Swash Plate:
It is the most important part of this pump.
The flow rate of the pump depends upon the angle at which the swash plate is mounted inside the pump.
If the angle of the swash plate is more, the flow rate will be more and if the angle of the swash plate is less then the flow rate will be less.
The position of the swash plate is fixed. It does not have any movement.
The swash plate is mounted at an angle to the axis of the cylinder block. This angle is 30 degrees on swash plates manufactured by most companies.
But this angle is different for swash plates manufactured by different companies. The minimum angle at which the swash plate can be mounted on the cylinder block is 17.5 degrees.
3) Cylinder Block:
This is the block that contains the piston and the hydraulic oil gets sucked and exits from this cylinder block.
4) Piston:
The piston is mounted in the cylinder block with the piston rod.
5) Shoe Plate:
The shoe plate is used to connect the swash plate and connecting rod of the piston. The shoe slides on the swash plate and undergoes a circulatory motion.
6) Spring:
Spring is placed between the piston and connecting rod.
7) Valve Plate:
The valve is circular in shape and the inlet and the outlet port are made on this valve plate.
7) Inlet Port:
It is used for the suction of hydraulic oil. From this port, the hydraulic oil enters the cylindrical block.
8) Outlet Port:
It is used for the delivery of hydraulic oil. From this port, hydraulic oil exits the cylinder block and enters the system.

Working Of Slash Plate Pump:-

When the drive shaft rotates using the motor then the cylinder block also rotates with it.
The whole system of cylinders, pistons, connecting rods, and shoe plates rotate with it.
The swash is connected to the piston through connecting rod.

The swash plate remains stationary and it does not rotate. Also, the inlet port and the outlet port remain fixed as the valve plate remains stationary and does not rotate.

As the swash plate is mounted at an angle, so when the cylinders rotate the distance between the cylinders and the swash plate varies.
The distance between the swash plate and cylinders increases in one half of the rotation and decreases in another half of the rotation.

Multiple cylinders are there on this pump.

During the one-half of the rotation, when the distance between the swash plate and cylinder block increases the piston is pulled towards the swash plate as the piston is connected to the swash plate using connecting rod.
As the piston is pulled towards the swash plate, space and vacuum are created and the hydraulic oil is sucked into the cylinder through the inlet port.

During the other half of the rotation, the cylinder filled with hydraulic oil reaches a position where the distance between the swash plate and the cylinder decreases and the piston is pushed behind and the space in the back side of the cylinder reduces and hence the hydraulic fluid exits from the cylinder through the outlet port.
As the hydraulic fluid exits from the cylinder again become empty and this process is repeated continuously.
There are multiple cylinders in the swash plate pump and all the cylinder undergoes the same process discussed above and in this way, the swash plate pump pumps the hydraulic oil or other fluid and supplies it to the required space.

therefore the piston reciprocates within the cylinder barrel. The piston reciprocates inside the cylinder in the direction of the axis of the cylinder.

The flow rate of the pump depends upon the following:
I) the number of cylinders (n)
ii) the speed of the pump
iii) the angle of the swash plate
iv) the bore diameter
v) the stroke length of the piston.

Types Of Swash Plate Pumps:

1) Through Screw Swash Plate Pump (Manual):
In through screw swash plate pump, the swash plate is connected with a screw.
When the screw is tightened, the angle of swash plate decreases and hence the flow rate of the pump decreases and eventually the flow stops when the swash plate angle becomes zero or when the swash plate becomes perpendicular to the piston.
When the screw is loosened, the angle of swash plate increases and hence the flow rate of the pump increases.
So the flow rate of the pump can be controlled by tightening or loosening the screw in this type of swash plate pump.

2) Inline Swash Plate Pump (Automatic):
The inline Swash Plate Pump is automatic swash plate pump means that flow rate of the pump can be controlled automatically. Also, the condition for the pump to start and stop can be set and can be automated.
In this pump a pressure point can be set to stop the pump. When the pressure point is reached the swash plate becomes perpendicular and swash plate angle becomes zero and hence the pump stops working.

Advantages Of Swash Plate Pump:

1) Swash Plate Pump has High Norminal Pressure.
2) They have Variability Of Displacement.
3) They have Good efficiency.
4) They have compact in size making it ideal for applications where space is limited.
4) They have through drive capability.
5) They have a low mass of inertia.

Disadvantages Of Swash Plate Pump:

1) Swash plate pump has a low viscosity range means the pump performance suffer when the fluid is too thick or too thin.
2) It has limited suction capability.
3) It has many moving parts which can ear over time which will lead to decreased performance.
4) It is more expensive than other types of pumps.

Applications Of Swash Plate Pump:

1) It is used in the compressor of a present-day automobile air conditioning system.
2) They are also used in automotive applications such as power steering, automatic transmission, and suspension systems.
3) They are also used in manufacturing applications like metalworking machinery, injection molding machine and hydraulic presses.