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Motor Mount and Wheel Kit (#27971)
Includes two 36-position Quadrature Encoder Kits (#29321)
The Parallax Motor Mount and Wheel Kit is a complete mechanical
drive system for sturdy and robust mid-sized mobile robots. It’s
comprised of two independent drive assemblies that are mirror
images of each other. Each assembly contains a right angle, worm-
drive gear motor, axle and ball bearing assembly, six-inch pneumatic
tire, and an integrated encoder system that provides feedback to the
microcontroller or processor of your choice.
Although this kit is designed for direct compatibility with our Robot
Base Kit (#28977), it can be easily adapted to a custom platform of
your choice or design using the pre-drilled, pre-tapped holes in the
precision machined 6061 aluminum mounting blocks.
Features
Drive system
Powerful worm-drive DC gear-motors
mount on precision machined 6061
aluminum hardware
Conveniently located pre-tapped holes
for easy mounting
Rugged pneumatic tires well-suited for
indoor and outdoor terrain
Powerful and strong, yet light weight
Encoders
36-position Quadrature Encoders
provide up to 144 pulses per revolution
Dual-signal out-of-phase outputs
indicate direction, pulse widths indicate
speed, and number of pulses indicates
distance traveled
Small form-factor and low
voltage/current operation are easy to
integrate with your robotic system
Key Specifications
Drive system
DC motor nominal operating voltage:
12.0 VDC
No load current: 1.50 Amps (approx.)
3.15 lbs. per drive assembly (two
included in this kit)
Approx. 150 RPM @ 12.0 VDC, 1.50 A,
no load
Encoders
Power requirements: 2.5 VDC @ 3.5
mA, 3.0 VDC @ 5.0 mA, 11.6 ma @ 5.5
VDC max.
Communication: two-channel high/low
pulse output
Dimensions: 2.0 x 1.1 x .25 in
(5.1 x 2.7 x 0.6 cm)
Operating temperature: 32 to 158 °F
(0 to 70 °C)
Product Change Notice
The original Motor Mount and Wheel Kit contained Position Controller Kits (#27906). The current version
of the kit includes 36-position Quadrature Encoder Kits. The 36-position Quadrature Encoder Kit is NOT
an electrical drop-in replacement for the Position Controller Kits.
The communication protocols and
electrical connections are substantially different
. Microcontroller code written for one system would not
be compatible for the other. For information about the Position Controller Kits search 27906 at
www.parallax.com.
Copyright © Parallax Inc.
Motor Mount and Wheel Kit (#27971)
v2.0 12/6/2012 Page 1 of 6
Bill of Materials
Part #
27958
27959
29321
34010
34015
34016
34021
700-00100
710-00015
710-00105
710-00110
713-00012
721-00004
721-00006
724-00001
Motor, 12 VDC (left)
Motor, 12 VDC (right)
36-position Quadrature Encoder Kit
Motor Bearing Block – 6061 Aluminum
Wheel, main rim – 6061 Aluminum
Wheel, rim ring – 6061 Aluminum
Axle, 6061 Aluminum
1/8 x 1” Roll Pin
1/4” – 20 x 0.5 Flat Head Screw
1/4” – 20 x .625 Button Cap Screw
M4 x 50 mm Socket Cap Screw
3/8” – OD, #8-ID x 1” Aluminum Spacer
Inner Tube, 6” x 1-1/4” Pneumatic, with valve stem cap
Knobby Tire, 6” x 1-1/4” Rubber
0.5” ID x 1.125” OD Ball Bearing
Description
Quantity
1
1
2
2
2
2
2
2
12
2
6
6
2
2
2
Mechanical Assembly
This section details assembling one motor, motor mount, and encoder. Two sets are included in your kit.
You will need the following tools:
Screwdrivers: #1 Phillips and flathead
Hex Keys: 3 mm and 5/32”
Small wooden mallet or hammer
Wood block
Tire pump, preferably manual
Step 1:
Remove any debris from the internal fins on the
encoder disk (a toothpick, fingernail or tiny screwdriver
works well). Then slide the disk onto the axle as far as it
will go. It should be a tight fit as you push it on, as the
internal fins of the disk conform and compress to the axle.
Step 2:
Insert the axle assembly into the Bearing Block.
This will be a very close tolerance fit. Take care to properly
align the bearing with the block while maintaining a gentle
pressure. Very gentle tapping with a wooden mallet can be
used if required. This close-tolerance fit is by design.
Copyright © Parallax Inc.
Motor Mount and Wheel Kit (#27971)
v2.0 12/6/2012 Page 2 of 6
Step 3:
Insert the motor shaft into the large diameter end
of the drive axle.
Step 4:
Insert the three M4 x 50 mm socket-cap screws
into the counter-sunk holes as shown. Slide three 1” long
standoffs onto the screws and then line up the screws to
the motor screw holes and tighten with a 5/32” Allen
wrench.
Step 5:
Insert the drive pin into the hole in the axle. You
may want to place the axle against a wooden block as you
gently drive the pin half-way through the axle. The pin
should be a very tight fit, and it should be centered in the
axle as shown here. Tighten the (3) socket-cap screws.
Step 6:
Do not over-inflate the inner tube—it will only take
a little bit of air—it’s safest to use a hand-held bicycle
pump. Inflate the inner tube just enough to eliminate any
wrinkles or folds in the rubber. Then, insert the tube into
the tire cavity, as shown.
Copyright © Parallax Inc.
Motor Mount and Wheel Kit (#27971)
v2.0 12/6/2012 Page 3 of 6
Step 7:
Align the main hub with the tube’s valve stem, as
shown.
Step 8:
Sandwich the two rims together, and secure with
(6) #4-40 x ½” Flat Head Philips screws.
You can assemble the wheel with the valve stem either on
the inside or outside of the robot. On the outside, it’s more
convenient to re-fill, if necessary. On the inside, it gives a
cleaner, more streamlined look. This picture shows the
valve stem oriented towards the inside of the Motor Mount
assembly (indicated by the drive pin slot on the hub).
Step 9:
Attach two cables to each of the Quadrature
Encoder boards, as shown.
Note the polarity and
orientation of the cables; the two white wires should be
adjacent to each other.
Step 10:
Attach the Quadrature Encoder board to the
Bearing Block as shown, using (2) 3/16 x 4-40 Flat Head
Philips screws. Be sure that the Encoder Disc is centered
within the Encoder sensor’s slot.
Copyright © Parallax Inc.
Motor Mount and Wheel Kit (#27971)
v2.0 12/6/2012 Page 4 of 6
Step 11:
Secure the wheel to the axle with a ¼”-20 x 5/8”
button-cap screw.
Step 12:
Attach the Encoder PCB using two # 4-40 x 1/8”
flat head Philips screws, as shown.
Be careful to align the Disc with the Encoder’s slotted
sensor.
Step 13:
Gently spin the wheel assembly, and watch how the encoder disk spins in relation to the
encoder’s slot. Adjust the disc such that it spins freely within the confines of the Encoder’s slot.
Copyright © Parallax Inc.
Motor Mount and Wheel Kit (#27971)
v2.0 12/6/2012 Page 5 of 6
模拟电子
