Tamiya Track Chassis + Gear Box Build

While searching for a chassis for my two-wheeled bot I came across an inexpensive track chassis from Tamiya.

The parts are:

  • 1 x Tamiya 70168 Double Gearbox Kit ~ $10
  • 1 x Tamiya 70157 Universal Plate Set (2pct) ~$9
  • 1 x Tamiya 70100 Track and Wheel Set ~ $8
  • 2 x Brushed DC Motor: 130-Size, 6V, 11.5kRPM, 800mA Stall ~ $4

I grew up making Tamiya models so it felt very retro putting it all together. I saw “(c) 1976 Tamiya” on one of the plastic frames.

Not sure how durable the chassis will be. The materials are not of bad quality but it’s fairly light plastic.

The first part I built was the twin motor gear box.

1200_1312_IMG_2838

The Packaging

1200_1312_IMG_2839

All the Pieces

There are four configurations to choose from:  12.7:1, 38.2:1, 114.7:1, 344.2:1. I chose 114.7:1.

1200_1401_IMG_2885

114.7:1 Configuration

As you can see from the instructions the assembly is quite involved but not too hard.

1200_1312_IMG_2843

Fully Assembled

The axles are metal but the gears are plastic. They do provide lubricant so hopefully that helps reduce wear somewhat.

Pololu (the website where I purchased the kits) recommends replacing the low-voltage/high-current motors, that come with the kit, with higher voltage motors that draw much less current, which is what I did.

1200_1312_IMG_2850

Adding the Motors

You’ll, obviously, need to solder wires to the motor terminal and it’s highly recommended to put a 0.1 uF non-polarized capacitor across the terminals.

When adding the capacitor you need to avoid blocking the area where the motor-housing for the gearbox “clips” on the the motor’s end cap – you can see it between he terminals in the image above and how I positioned the capacitor accordingly.

Next up was building the chassis and tracks.

1200_1401_IMG_2881

Track Set Packaging

1200_1312_IMG_2835

Track & Wheel Parts with 1 Universal Plate Set

For the track there are (for each side) a 1 x 30 link section, 2 x 10 link sections and 2 x 8 link sections. For my setup I used 1 x 30 + 2 x 10 + 1 x 8 sections to make each track. Joining the sections together is a little tricky. Helps to gently use a small flat head screwdriver to “pull through” the interconnecting tabs.

1200_1312_IMG_2860

Mounting the Gearbox

Mounting the gearbox requires cutting holes into the side of the universal plate and using a special mounting piece shown above. For my setup I position the mounting point 4 holes from the end of the plate.

1200_1312_IMG_2863

Wrong Driver Sprocket

The idlers I placed at the forward most point on the plate.

I initially used the large driver sprocket – as show in the photo above – for the rear drive but, as you can see, it is not inline with the idlers. I actually needed to use the small driver sprocket for the gear config I had chosen.

1200_1401_IMG_2872

Finished Track With Road Wheels

With the correct (smaller) sprocket in place I added the road wheels, mounted a 4xAA battery holder and used the second universal plate to create an upper deck where I can mount the electronics.

1200_1401_IMG_2876

Front View

View from the front. You can see the spacers I used to mount the battery holder and the upper deck.

1200_1401_IMG_2878

Side View With TopDeck

Side view showing motor (near) and battery (far) wires routed through the upper deck.

1200_1401_IMG_2870

View Without Deck

So far so good. The construction feels solid enough. Need to get the Arduino installed with its motor shield so I can take this for spin. So much to do, so little time…

Advertisements

One comment

  1. Very nice ‘how to’ building that robot! I have built that one too a while back, but not published any pictures or article about it. Too bad, I need to do this. Later, I have built a tracked robot based on the Tamiya gearbox, but using the Pololu Track pins and wheels: these tracks are very good and allow different designs, but the have not much grip on the ground. You can see it here:
    http://mcuoneclipse.com/2013/05/25/tracked-robot-update-ultrasonic-line-sensor-and-shell-with-smac-802-15-4/
    and here:
    http://mcuoneclipse.com/2013/05/12/freedom-track-robot-with-ieee802-15-4/

Comments welcome

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s