Specifications

K
K4
Parker Hannifin Corporation
Pneumatic Division
Wadsworth, Ohio
www.parker.com/pneumatics
Pneumatic Actuator Products
Air Motors
Principles of Motor Operation
There are a number of designs of air motors. Parker Hannifin has
chosen to use the vane rotor design, because of its simple design and
reliable operation. The small external dimensions of vane motors make
them suitable for all applications. The complete unit consists of a motor
built together with a planetary reduction gear to give the required
speed and torque at the output shaft.
The design of a vane air motor consists of a rotor which incorporates
a given number of vanes all enclosed within a cylinder. The cylinder
will include three ports; an inlet pressure port, an exhaust port and a
residual port. Reliable starting is ensured by the fact that the inlet air
presses the vanes against the cylinder wall prior to rotation. During
operation, the vanes are pressed outwards by centrifugal force. The air
pressure always acts at right angles to the vane surface, which means
that the available torque is determined by the surface area of the
vanes and by the air pressure. As each vane reached it’s lowest point
air is released through the exhaust port. As the rotation continues air
may be trapped and compressed between vanes. This compressed air
is released through the residual port. The residual port doubles as the
pressure port when the motor is operated in the reverse direction.
Inlet
Inlet, left Residual outlet Inlet, right
1 Rotor cylinder
2 Rotor
3 Vanes
4 End piece with bearing
The performance characteristics of each motor are shown in a family
of curves as above, from which torque, power and air consumption
can be read off as a function of speed. Power is zero when the motor
is stationary and also when running at free speed (100%) with no load.
Maximum power (100%) is normally developed when the motor is
braked to approximately half the free speed (50%).
Torque at free speed is zero, but increases as soon as a load is
applied, rising linearly until the motor stalls. As the motor can stop with
the vanes in various positions, it is not possible to specify an exact
starting torque. However, a minimum starting torque is shown in all
tables.
Air consumption is greatest at free speed, and decreases with
decreasing speed, as shown in the above diagram.
Torque, Power and Air Consumption Graphs
1
2
3
Outlet Outlet
4 3 1 2 4
Outlet
4020 60 80
100
160
120
140
200
180
100
100
20
40
60
80
20
40
60
80
M
Q
P
Q (%), P (%)M (%)
n (%)
Possible working range of motor.
Optimum working range of motor.
Higher speeds = more vane wear
Lower speeds with high torque = more gearbox
wear
The curve is for 6 bar
P = power Q = air consumption
M = torque n = speed
Please refer to the curve on page K63
for these pressures:
3, 4, 5, 6 and 7 bar
Catalog 0900P-E
Technical Information