Boxerlego's Monster Truck

[Boxerlego]

Hello, I want to share this Monster truck project that I've been working on and show you the early development of the creations to the design I've got going now. First I want to tell you that this monster truck was made along with the construction the 18volt motor. That 18v motor was made to be power plant for this design.

I will start with this picture of the test model that tested the 18-volt drill motor to see if the LEGO gear train could handle the power of the 18volt motor. I made a video showing this test. (Video link:

) The test results were good for everything except the differentials. The test model had front wheel steering but no control mechanism. The early stages of the 18-volt drill motor required a direction connection to a power supply in order to run.

The next version of monster truck used portal hubs on the back axle and the 6.5x2 steering arms on the front to create a positive caster angle on the front axle for direction stability. This also had steering but no control mechanism. (Video link: http://youtu.be/56SwhIxCaJA?t=2s)

The second version had steering on the front axle but not on the back; However, The steering design was focused on using two servos to operate there respective front and back axles. I also had made a H bridge so I can put more voltage on the motor with a V1 IR receiver and power the motor in both directions. This is also when I used a metal washer to strengthen the differential. (Video link:

)

The third version is what is begin built now and is about half way done. This design currently has the possibility of begin all wheel steering and 4 wheel drive from the function of one servo and one motor. I am also considering to not have the battery box inside this design but that still remains a question. The steering on this is the same rack and pinion style on the 8466 4x4 off roader. I am using the pinion gear ability to move back and forth on the rack to act as a kind of telescopic joint to move with the 4 link suspension. Some of the side on the 8 tooth gear will be need to be removed to achieve this telescopic movement. The frame is a unique approach to LEGO construction. It involves in using 3mm rigid hose to make necessary adjustments to the axle members to make the necessary alignments with the studless uniform pattern. (Topic link: http://www.eurobrick...showtopic=81752)

I will start the topic with this picture

Enjoy!

Edited April 30, 2013 by Boxerlego

[Someonenamedjon]

I like how you used the custum motors.

[Eigenbroetler]

nice chassis!

[Nazgarot]

I love this. I've wanted to make one for my self for years, but lacking powerpuller tires (just got some) and finding the motor to weak has stopped me... I do how ever have an idea now, thanks to you.

Thank you for shearing! I can't wait to see it finished.

-ED-

[Boxerlego]

Thanks everyone for the comments! I want to focus on the differentials first because it was a must for it to be on the monster truck. I would not have come this far if nothing couldn't be done to improve the differential. So I hope this topic will be a great help to those that want to put some torque to their differentials in their MOCs. Now here are some of my thoughts on the differential and using the shim with it. The differential design is great because of the fact that you can use a shim to strengthen it and also that the differential rides against the shim and not the frame. Shimming the differentials up was the most apparent solution to improve the transfer of torque. To me it appears that the 3L differential are made for shimming. There is a picture below of two nylon washers used to shim the differential gear up. I got the nylon washers in a hardware store opposed to the metal washers I found laying around in the garage. The metal washers were a test shim with the differential and because of its small size and big open center they would fall out of place with the drive gear on the slopes and the differential would slip gear. The nylon washer is an excellent shim and can be sanded down for a great loose fitting support against the differential gear and will not fall out of place with the drive gear at any angle. The nylon washer is about 1mm thick and 32mm in total diameter and the center hole is 10mm in diameter and cost $0.70 each.

[DLuders]

@ Boxerlego: That's a good idea -- did you find those nylon washers at Lowe's, Home Depot, ACE Hardware, or another national store chain?

[Boxerlego]

@DLuders: I got the nylon washers at the "do it best" hardware store. I've been looking for the nylon washers on the online store and found nothing. They have a bunch of different sizes of nylon washer available. The nylon washer I got was as thin as they get at the store I was at. I haven't been to the other hardware stores looking for nylon washers. Thanks!

Edited April 30, 2013 by Boxerlego

[AndyCW]

The best online source for these kind of things that I have come apon is called mcmaster car. They have everything for interesting projects. Many of the parts on experimental UAVs that I have worked on utilized McMaster Car parts extensively.

http://www.mcmaster.com/

v/r

Andy

[Boxerlego]

@AndyCW: Thanks for the Link. There was some very interesting items there.

Update:

I've expanded the shocks distance from 7 modules to 9 modules. I built the axle design with the intended thought of using the rack and pinion for steering. On real monster trucks they use hydraulics for their front and real steering. The mechanical force of a rack and pinon is too weak to move the massive monster truck tires.

Here is the nylon washer.

Here is one of the pinion gears the was modified to allow some telescopic action.

Edited May 23, 2013 by Boxerlego

[LEGO Train 12 Volts]

Thanks everyone for the comments! I want to focus on the differentials first because it was a must for it to be on the monster truck. I would not have come this far if nothing couldn't be done to improve the differential. So I hope this topic will be a great help to those that want to put some torque to their differentials in their MOCs. Now here are some of my thoughts on the differential and using the shim with it.The differential design is great because of the fact that you can use a shim to strengthen it and also that the differential rides against the shim and not the frame. Shimming the differentials up was the most apparent solution to improve the transfer of torque. To me it appears that the 3L differential are made for shimming. There is a picture below of two nylon washers used to shim the differential gear up. I got the nylon washers in a hardware store opposed to the metal washers I found laying around in the garage. The metal washers were a test shim with the differential and because of its small size and big open center they would fall out of place with the drive gear on the slopes and the differential would slip gear. The nylon washer is an excellent shim and can be sanded down for a great loose fitting support against the differential gear and will not fall out of place with the drive gear at any angle. The nylon washer is about 1mm thick and 32mm in total diameter and the center hole is 10mm in diameter and cost $0.70 each.

Nylon! Very neat solution!

[Boxerlego]

I've been thinking about using the pneumatics for the front and rear steering. One problem is air pressure has some lag when the pressure is low; however, the pneumatic are able to put more steering force than the servo. So I am going to use the pneumatic for the steering and Alasdairryan video has convinced me enough to do this. Thanks Alasdairryan.

[Boxerlego]

Update: I have reworked the axle member. This axle design replicate what the 9398 crawler does and that is to have the motor on the drive axle and instead of rack and pinion it uses a pneumatic cylinder for steering which also sits behind the motor. I've built the axle design around the upgraded XL motor so it can use the XL motor here. The pneumatic cylinder that sits behind the motor is mm away from touching the motor. There are picture down below for you to click on and see. The first two pics show the range of the cylinder.