RHEFOR has developed a new concept for bistable solenoids
and applied for a patent.
Compared to conventional solutions this new technology
SPECHT exhibits:
up to 3x higher force at a given volume
shorter operating time
shorter delay time
lower power consumption due to high efficiency
Within certain dimensions SPECHT allows the avoidance of expensive rare
earth magnets. If not a proportional but a pure switching function is
required, SPECHT may in many cases replace pneumatic cylinders. Thus, by
avoiding expensive compressed air, SPECHT can help lowering operating
costs.
SPECHT is easily scalable. It can be build rotationally symmetric or
in the form of cuboid from sheet metal packages.
The actuator is under continuous development and will be adapted to customer specific requirements.
The possibilities are demonstrated by the following FEM-simulation results.
example-actuator ⌀=50 mm, l=59 mm with 3 mm stroke and >400 N force
Simulation assuming conventional materials (free machining steel) and direct
24 V supply with a coil resistance of 12 Ω.
stationary characteristics of the actuator:
transient simulation of the actuator in the unloaded case
(no external mass, no external restoring forces),
energy loss per cycle 0.5 J (η=4.9%):
transient simulation of the actuator with a constant counter force of 200 N,
energy loss per cycle 2 J (η=0.9%):
With soft magnetic composites and added electronics
much improved timings and energy conversion efficiency are possible.
transient simulation of the actuator in the unloaded case,
energy loss per cycle 0.02 J (η=97%):
transient simulation with a constant counter force of 200 N,
energy loss per cycle 0.8 J (η=35%):
example-actuator 35 mm x 35 mm x 71 mm with 6 mm stroke and ≈50 N force
stationary characteristics of the actuator:
A variation of the SPECHT-actuator allows for the optimization towards
a particularly low velocity in the end position. Thereby a exceedingly
low noise level and low material wear during operation can be achieved.
example-actuator 92 mm x 92 mm x 174 mm from laminated sheets with 10 mm stroke and ≈3 kN force
stationary characteristics of the actuator:
transient simulation with a load of 25 kg and
energy losses of 4.4 J per cycle (η=71%);
direct 100 V supply with a coil resistance of 5 Ω,
the actual transient peak power is only 500 W:
example-actuator ⌀=24 mm, l=16 mm with 500 µm stroke; monostable layout
stationary characteristics of the actuator:
transient simulation of the unloaded actuator with direct 24 V
supply and a coil resistance of 58 Ω;
actual transient peak power 8.5 W;
energy losses per cycle of 43 mJ (η=0.3%):
transient simulation of the unloaded actuator
with 24 V-capacitor as power supply
and a coil resistance of 2.6 Ω;
actual transient peak power 60 W;
energy losses per cycle of 29 mJ (η=41%):
example-actuator 157 mm x 115 mm x 135 mm from laminated sheets
transient simulation with a load of 50 kg and
energy losses of less than 70 J per cycle:
example-actuator ⌀=26 mm, l=40 mm
transient simulation of the unloaded actuator with
energy losses of less than 47 mJ per cycle