Load coupling
The SQL-1.8 SQUIGGLE motor delivers millimeters of stroke with
sub-micrometer precision and high linear push force. Mount the motor
in your system so that the rounded tip of the motor screw presses
against a flat, hard surface on the load to be moved. For optimal
performance, this radiused screw tip should contact a hardened,
polished, low-friction surface. The tip should not be affixed to the
surface, but rather allowed to rotate freely against it.
 The screw will push the load in the
“forward” direction. The motion of the load must be in line with the shaft centerline as shown
- do not apply a side load to the motor screw.
The motor requires a slight
loading force (5g) to keep the screw threads engaged in the motor
body for optimal forward motion. This load is also called the "return
force" as it also moves the load in the “reverse” direction when you
reverse the motion of the screw.
Important notes about load coupling
- Use a return force or loading force, such as a
spring.
- For applications where the motor will hold the load in a
"locked" position, the direction of the return force should be
in the locking position, so the mechanism will remain
locked if the system is subject to strong vibration.
- Do not apply a side load to the motor. A common
mistake is to fix some sort of component (end cap, disc etc.) on
to the screw and then to apply a side load to the component.
This will shorten the life of the motor and can be avoided by
decoupling the component from the screw as shown.
- Avoid excessive friction in the system. This
excessive friction is usually caused by a side load.
Mounting methods
For optimal performance your mounting method should limit or
eliminate any outside forces on the motor body (inside the stainless
steel housing). This is easily achieved using the mounting tabs on
the housing (see below) or by applying an adhesive to the base of
the housing.
Snap-In Method
The snap-in mounting method consists of a user-supplied
“integration structure” with a recess to accept the bottom datum
of the motor housing, constraining it in the X and Y axes. Use
two “snap tabs” to secure the housing in the recess by clamping
onto the mounting tabs, constraining it in the Z axis.
Adhesive Method
The adhesive method consists of the same type of recess as in
the snap-in method, but without the snap tabs. Instead, an epoxy
or adhesive tape applied to the bottom datum of the housing
would be used to secure the motor housing in the recess.
Clamp Method – Not Using Mounting Tabs
This first clamp method does not utilize the mounting tabs. It
consists of the same concept as the adhesive method, but with a
separate part (preferably a thin sheet metal part) that is
screwed into the integration structure in two places and clamps
onto the top of the motor housing. This clamping force should
not exceed 100g.
Clamp Method – Using Mounting Tabs
The second clamp method consists of the same recess as
before, but with a separate part that is screwed into the
integration structure and clamps onto one of the mounting tabs.
The other mounting tab slips into a “pocket”.
Additional mounting considerations
As with any threaded system, driving the SQUIGGLE motor screw
linearly into a physical stop increases the risk of jamming the
threaded components and possibly damaging the
motor. Linear “hard” stops should be avoided. “Soft” or electrical
limits such as optical sensors or magnetic Hall-effect sensors are
recommended.
External vibrations can potentially move the screw when the motor
is not in operation. This can lead to improper positioning, allowing
the screw to move past a forward or reverse limit. An applied
return force can prevent this.
For more information
Please register to
download additional information including 3D CAD files and the
SQL-RV-1.8 or SQL-1.8 Series SQUIGGLE Motors User Manual.
Custom engineering assistance
New Scale engineers can assist OEM customers with integration
structure design, create customized motor housings, or design
complete application-specific modules (including drive electronics
and
miniature position sensors) to fit your requirements. See our
custom
engineering page for more information.
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