RC Dozer

Remote Control Dozer Story:

I was looking at large RC Bulldozers after seeing the prices for one approximately this size,
I decided to print one. This is aimed at more function verses scale model of specific design.
Also wanted the motor away from Water / Dirt, etc. With the Drive Gears 3D printed,
thought the track wrapping around half of Drive Gear should reduce slippage / jumping teeth.
This has 2 drive gears per track, unlike many others only having 1 drive gear per track.
Updates will be added to this Instructable as modifications evolve .

This weighs 4.5 Kg (10 Lbs) with no batteries.
Planning on adding lead weight (starting in lower area of front, ? on amount)
A cab could be added, printed printed or made from other material.
Without Cab the Dozer is: 450mm x 330mm x 165mm, (L x W x H).
With proposed cab estimating height to be 265mm.

Radio control upgrade will be phase 2 if this performs well.
This is a good foundation to build on, many cosmetic and functional additions can be added
Maybe a Construction Equipment Series is started . . .
Possible builds (Track Hoe, End Loader, Dump Truck, Crane, etc.)
one step at a time.
The STL files can be printed on a 200 x 200mm 3D printer or larger.
"Big Red 3d Printed Printer " another Instructable was used to make some parts.

- - - - -
Remote control Dozer uses 2 "L298N motor controllers", (activated by push buttons).
1 for drive motors and 1 for raising & lowering blade

• Left Forward
• Left Reverse
• Right Forward
• Right Reverse
• Blade Up
• Blade Down

This version will be using a wired controller.
No battery in controller, power comes from Dozer (Controller is a switch only)
An Arduino would allow Dozer to be radio controlled or IR controlled ..

Supplies

Access to 3d Printer, Solder Iron, Electrical tools, assorted wrenches
6 - M8 threaded rod 300mm long (Frame & Idlers)
1 - M8 threaded rod 150mm long (Yoke top of Blade Lift)
1 - M8 threaded rod 125mm long (Blade lift)

Needed for Optional Blade if making:
1 - M8 threaded rod 125mm long (inside of Yoke)
1- M8 threaded rod 350mm long (Top of Blade for Lift Linkage point)

12vdc Battery (wire in parallel if using 2+)
7 -Strains of wire 3+ meters each. to connect control box to Dozer.
Or 1 cable with 7+ conductors
Some short misc.wire for components in Dozer
1 - Off/On Switch
6 - push buttons
2 - Strain Reliefs
1 - Shaft Coupler 6mm to 8mm. (For Blade Lift)

2 - L98N Motor Controllers
2 - 12vdc Motors 300 rpm (For Tracks)
1 - 12vdc Motor 200 rpm (For Blade Lift)
1 - Box of 100 pcs. of 8M Nuts
8M lock nuts can used in some areas. Other areas need 2 nuts for spacing
1 - Box of 100 pcs. of 8M Flat Washers
10 - M8 x 35 bolts (for frame)
2 - M8 x 45 bolts (Mount Blade arms to frame)
4 - M8 x 25 bolts (for frame & Blade)
18 - M3-.50 x 10 (For Motors)
8 - M3 x 10 with Nuts (Bolt Motor Hub to Drive Gear)
8 - M4 x 40 Bolts & Nuts (For Drive Gear Assy.)
2 pkg. of track with 2 pcs. ea. (splice 2 together to make 1 track.)

2 - L298N Motor controller: https://www.amazon.com/dp/B072MDKT9B/?coliid=I366X...

3- 12vdc- Gear Motors: https://www.amazon.com/dp/B072N84V8S/?coliid=IZ4K2...

2 - Hubs to mount drive gear to motor: https://www.amazon.com/gp/product/B07PDYNN18/ref=o...

2 - gazechimp Assembly Plastic Tank Track Removable Tracked Chassis F/ Robot DIY Part,2pcs

Track Link: https://www.amazon.com/gp/product/B07W1R2MSY/ref=p...

1 Pkg Motor Shaft Coupler (comes in pkg. of 2 need 1). https://www.amazon.com/Twidec-Flexible-Coupling-Co...

Step 1: Control Box

There are 2 boxes to choose from, 1 with holes or 1 without.
Use the version that works for you.
the blank one can be drilled for your push buttons.
Print the box you want to use and a Lid

Install a strain relief for the cable, route cable into box.
Attach wires to correct switches per wiring diagram.
The cover can be snapped into place or glued.

Button layout:

Left Forward ------------------ Right Forward

Lower Blade ------------------ Lift Blade

Left Reverse ----------------- Right Reverse

Step 2: Printed Parts Information

All parts are printed in PLA @ 20%
1.6mm for shell & top an bottom layers thickness
The Rear sides need support turned on, for a good motor mount area.
The Idlers have a support ring coded into the stl file.
The Drive Gear may need to be higher percentage.
Drive Gear could be made from Nylon, ABS, Tech G. or ....
I will post my results of printed gears in PLA as they develop.

Printed Parts List:

10 - roller idler A (remove support ring after Printing)
10 - roller idler B (remove support ring after Printing)
1 - side front
1 - side rear (use support when printing)
1 - Mirrored side front
1 - Mirrored side rear (use support when printing)
3 - center braces
4 - 20tooth crawler robot style drive gear A (Drive Gear)
2 - 20tooth crawler robot style drive gear B (Motor Hub)
2 - 20tooth crawler robot style drive gear C (Inner Spacer)
2 - 20tooth crawler robot style drive gear D (Outer Spacer)
1 - Blade Yoke
1 - Blade Motor Mount (Lift / Lower Blade)
2 - Blade Pivot (To attach Blade to or used to lift optional blade)

The follow parts are optional: Blade Lifted by Blade Pivot:
2 - Blade Mounting Bar A (Track Shield - rear- with blade Mount)
2 - Blade Mounting Bar B (Track Shield - front)
2 - Blade Mounting Bar C (Part of arm that Connects to Frame)
1 -Blade Mounting Bar D (Part of arm that Connects to Blade)
1 -Mirrored Blade Mounting Bar D (Part of arm that Connects to Blade)
1 - Blade Bottom Support
1 - Mirrored Blade Bottom Support
1 - Blade 1 (Lower part of Blade with Scraper edge)
1 - Mirrored Blade 1 (Lower part of Blade with Scraper edge)
1 - Double Yoke for Lifting Blade. (Uses support to print this)

Step 3: Assemble Frame & Blade Lift:

Remove the support ring from all of idler A and idler B.
Glue: 1- Idler A to1 - Idler B making 10 Idler rollers.
Insert a 608 bearing in each side of rollers
Smaller Gears or different gear box would change speed / torque.

___

Mount Motors to rear sides
___

Assemble Front and rear sides
Install threaded rods with (motor Mount assy. & the Blade Pivots
bolt center braces to bottom of sides
___

Bolt the rear center brace to sides
___

Check pictures for correct placement of Linear Actuator and
Blade pivots, when installing threaded rods.
Extra nuts and washers and parts need to be installed.
___

Install all the threaded rods.
Add extra parts,nuts & washers as needed.
(1washer--4 nuts--1 washer) on each rod on the inside area of Dozer.
measure each side of threaded rod adjust the nuts
to make measurement equal on each side.
after measurements equal lock the 2 nuts together
avoid spreading the sides out when tightening nuts.
___

on the outside of frame put:

(washer - 2 nuts)
tighten nuts against frame and lock the 2 nuts together

__

Next, put (washer - 1 assembled idler roller - washer - 2 nuts or 1 lock nut)
tighten nuts checking for roller for proper movement..

__

See pictures for more information.
Hopefully this is clear if not refer to pictures for help.
The use of all the nuts & washers gives correct alignment of idlers.

Step 4: Optional Blade Assembly:

This will cover the Optional Printed Blade Skip if not Using:

Assemble the 2 halves of Arms.
Assemble the 2 halves of Blade 1.
Fasten the Blade 1 Assy. to Lower Blade support.
---
Put the Double Yoke to the 8M x 350 Threaded Rod. (grey color part)
Center the Double Yoke (using offset Hole) of the 350mm Threaded Rod.
The inline hole of the Double Yoke is attached to Blade Lift.
Next put 2 nuts on each side of Double Yoke.
Attach Arms to Blade Assembly.
----
The Track Shield with Pivot for arm needs a 8M x 45mm bolt installed
from the back side. This is what the Blade Assembly Arms will pivot on.
This Track Shield mounts to the Center & Rear Idler.
The blank Track Shield is mounted to Center & Front Idler.
---
Attach the lower part of Double Yoke to lower hole of Blade Lift.
using the 8M x 150 mm Threaded Rod, tighten the double nuts or lock nut
against each other ensuring both Yokes move freely.

Step 5: Yoke & Drive Wheel Assy:

YOKE Assembly:

Put 1 - (8M nut) in square hole (small end of Yoke).
Use a 8m bolt to pull the 8M nut into nut trap by tightening the bolt.
After the nut is seated in the trap.
Remove the 8M bolt, leaving the 8M nut in trap.
Rotate the (8M x 125mm) threaded into nut.
Put the motor coupler on The 8M threaded Rod.
Blue coupler in picture.
See pictures for more info.

The actuator could have micro switches added to limit travel.
The current application will stall motor at end of travel,
something to be aware of so you don't damage your motor.

___

Drive Wheel Assembly:

Each drive wheel consists of:

4 - M3 x 10 Bolts & Nuts (Bolt Motor Hub to Drive Gear C)
4 - M4 x 40 Bolts & Nuts (For Drive Gear Assy.)
1 - Motor Hub (aluminum)
2 - 20tooth crawler robot style drive gear A (Drive Gear)
1 - 20tooth crawler robot style drive gear B (Motor Hub)
1 - 20tooth crawler robot style drive gear C (Outer Spacer)

Assemble:
Bolt; Drive Gear B (Printed Hub) to 1 Aluminum Motor Hub) with 4 - M3 x 10 Bolts
Flange against aluminum hub (flange thickness creates correct track spacing from frame)
Refer to picture for correct orientation of parts.
Tighten the 4 - M3 nuts

Put; 4 - M4 x 40 Bolts through Drive Gear A (Printed Gear)
Slide assembled Hubs (Aluminum & Printed parts) on to M4 Bolts .
Next slide Drive Gear A (Gear, Flange first) on to M4 Bolts .
then slide Drive Gear C (Outer Spacer) on the long bolts
Put 4 nuts on the 4M bolts.

Review and tighten.
These are ready to mount on Motors (after motors are installed).
Refer to pictures for correct orientation of parts.

Step 6: Wiring

Wire the motors, Battery, boards, etc. using diagram

Step 7: Optional Cab

Starting with a base of cab bolted to main frame.