All AndyMark gearboxes require grease for proper operation and long life. We suggest using our red tacky grease, am-2768. We also encourage that the user powers the gearbox continuously for 30 minutes without grease to allow the gear teeth to wear in. While we do design with short run times in mind, this 'run in' period for smooth gearbox operation, is recommended. Once this is completed, thoroughly grease the gear teeth periodically to ensure smooth operation.
NOTE: When operated correctly the angle of the worm in the RAW Box allows it to back-drive.
The RAW Box is a strong, compact gearbox utilizing CIM Motors. Steel and brass worm gears are used in order to provide a setup where the CIM Motors are located at a right angle from the output shaft. Since one or two motors can be used as input for this gearbox, and the gears are made of strong materials, this gearbox can provide a high level of torque.
The worm gear shaft is driven by a spur gear. This spur gear is driven by another spur gear located on the output shaft of the CIM Motor. These two spur gears can have their position swapped in order to change the overall reduction of the gearbox. The Standard Ratio (14.2:1) is how the gearbox is pre-assembled and shipped. The Switched Ratio (7.1:1) is what the user can get, after re-positioning these gears.
This gearbox design is heavily influenced by the two-motor Right Angle Worm gearbox made by student designer Joey Milia of FRC team 192, GRT (Gunn Robotics Team) from California. Joey and GRT came up with this successful design for the 2012 FIRST Robotics Competition. Thanks, Joey and team 192 for providing this design to AndyMark so that the robotics community can utilize this design!
- Material: 4140 Steel
- Maximum Output Torque: 90 ft-lbs
- Output Shaft Size: 1/2" Hex
- Ratio: 14.2:1,7.1:1
- Weight: 1.39 lbs
These perform well with no issues; removed a star due to motor mounting hole misalignment on one of the two we got.
"Could be better"
"The raw boxes have served only one purpose on our team: to be a go-to system until we find something better. Unfortunately, our raw boxes we have purchased have all quickly degraded to being able to be back-driven. They have a good ratio and design, but upon receiving them, we had to oval out some of the mounting holes because of inaccuracy and we were unable to mount our own CIMs to them. In the case that these issues would be fixed, easily would have earned 5 stars. (AndyMark Response: The product page states this gearbox is back-drivable due to the angle of the the teeth on the worm. We will make the information more clear. Thank you for the feedback.)"
"Excellent choice this season"
"We had one on the front and one on the back of our 2015 bot running chain/hook elevators. Both lasted through 2 regionals and the Worlds without issue. They handled the weight of 5 totes ea. without back driving. We did have to tap holes for our encoders to mount - adding that would be an improvement. Also, the build quality looked a little rushed and probably was due to demand. We originally had some noise in one and had to disassemble part of it and re-align. The CIM holes on the other were off slightly. All in all a great gearbox though. (AndyMark Response: Thank you for the compliments, we are looking into adding encoder mounts and will continue to work on quality improvements, thank you for letting us know.)"
"The RAW Box gets the job done!"
"I was very impressed by the compact size, solid construction, and easy assembly of the RAW Box. In all of our testing, the RAW Box did not back drive (tested with loads exceeding 60 lbs) while powering a simple single compound pulley system. Well done!"
A little expensive!
I was very surprised to see how well built and compact this gear box is. Just wish the price was more reasonable.
"Great Gearbox :D"
"Is it possible to attach an encoder to this gearbox? Also is it possible to attach two drive shafts (i.e. to connect a drive shaft to both sides of the gearbox)? Thanks in advance."
"The installation is quick and easy and the gearbox takes up very little space, leaving a wide amount of room in the center of the robot! (I'd like to point out that Ed Fitz's questions about how the cims mount can be solved very easily by reading the enter description)"
"How to use RAW?"
"As a mentor of a rookie team, it is not obvious how to use the RAW. The product needs a few more pictures. How do the CIM motors mount on the RAW? How does the RAW mount on a C channel frame? I have used two CIMs on a toughbox, Why is this better?"