Select Ratio B (available options based on Ratio A)*:
*All selections Required
Ratio A Speed (ft/sec)
Ratio B Speed (ft/sec)
Total Price: $
EVO Shifters are built to order. Pease allow 1-2 days build time after purchase.
Product Overview: The EVO Shifter is our next EVOlution of a shifting transmission gearbox. It's design was developed from the lessons learned during our experience using the AM Shifter since 2004, the Super Shifter since 2007 and the Sonic Shifter since 2013.
This transmission is a two-speed, shift-on-the-fly gearbox, using an improved 4-tooth dog shifting method. Motor input can be two or three CIM motors (or AM Planetary Gearboxes). The transmission can be configured with two or three interior stages, and a selection of various 1/2 inch output shafts. Plates are designed for mounting either two or three CIM motors. No servo shifting is available with this shifter. This transmission is shipped assembled, but without the CIM motors installed, even if the CIM motors are ordered with the gearbox.
Improvements: Fourteen significant improvements, not seen in previous AndyMark shifters, have been implemented in the EVO Shifter.
The dog gear now has 4 dogs on each face. This allows more material around the dog gear screw, increasing strength over previous designs.
A robust 1/8" diameter shoulder screw replaces the previously used #4-40 screw.
The dog gear material is AMPCO® 18 Bronze. This material has similar properties to stainless steel (previously used), but has added lubricity for smooth shifting.
A new, super-strong shift block assembly with a larger bearing and steel housing (and threads!) is now included.
The input stage uses 32 DP gears and a press-fit 15 tooth CIM gear. This allows for an 85:15 first stage reduction.
This gearbox allows users to independently pick their high and low ratios, and are no longer confined to two set spreads.
The user can swap the ratios (A to B, B to A) as needed.
Aggressive weight reduction features have been machined into the gears and plates.
All of the cluster gears have the same features surrounding the bore on both sides. This allows the user to dis-assemble and assemble the shifter without worry of correct gear orientation.
Users can pick two or three stages for their transmission. An optional 3rd stage provides an additional C ratio choice of 1:1.14 or 2:1.
CIM Motors (2 or 3) can be ordered with the transmission. If these are configured with the product, then they will be shipped with the CIM gear installed on the motor shaft.
Using existing mounting plate holes, it can be mounted to an AM14U family chassis or a 2"x1" box tube frame.
A short, narrow air cylinder is being used, taking up less length compared to previously used cylinders.
Air Cylinder Shifting: The EVO Shifter only uses a pneumatic shift method.
A spring-extended PHD pneumatic cylinder (am-3494), powers the shift. This pneumatic shift can be done while a robot is accelerating, pushing or decelerating.
Extend Stroke (spring extend only): 4lbs
Extrend Stroke (if air actuated, 40PSI): 21.6 lbs
Retract Stroke (air actuated, 40PSI): 15.7lbs
This cylinder extends into the selected "Ratio A" when no air pressure is supplied. This allows a robot to continue to drive using Ratio A if air pressure is lost.
Weight Range (Without Motors): Two Stage: 2.9 - 3.2 Pounds Three Stage: 3.3 - 3.5 Pounds
Note about CIMs: The EVO Shifter utilizes a 15 Tooth 32DP gear as the CIM gear which requires a press fit. Due to the intended interference fit (0.001 - 0.002") along the 0.750" long gear, a minimum 3 ton arbor press is required to install this gear onto the motor in conjunction with a provided aluminum spacer to help set the distance of which the pinion should be installed from the end of the motor shaft (approximately 0.40"). If you do not have access to this size arbor press, we have the option to add CIM motors to your order with the pinion gears pre-installed, available as am-0255_15T. Usage, Greasing and Break-in: All AndyMark gearboxes require grease for proper operation and long life. Use our Red Tacky Grease, 14.2 gram (am-2768). However, before applying grease, it is helpful to run the gearbox for 30 minutes without grease to allow the gear teeth to wear in. While we do design with short run times in mind, this 'break in' period for smooth gearbox operation is recommended. Once this is completed, apply grease to the spur gears periodically to ensure smooth operation. No grease is needed on the AMPCO® bronze dog gear. Encoder Ratio:
When programming for the encoders, please know that the ratio between the Output Shaft and Encoder Shaft of the EVO Shifter is 3:1. The Output Shaft's 20T 32DP gear mates with a 60T 32DP gear on the Encoder Shaft.
Quantity of 4 for 2 Motor or Quantity of 6 for 3 Motor
1 - Aluminum Spacer (am-3552)
Gearing and Ratios:
The selection menu above allows users to select their best choice from many ratios. If the user knows their wheel diameter, then they can choose their first ratio and second ratio, and also see approximate speeds (listed in feet/second).
Select your ratio options:
Determine your wheel diameter
Choose Ratio A
Choose Ratio B
Verify your approximate speed, depending on the CIM motor working RPM.
Output Shaft: Four choices of output shaft geometry are available for the 2 and 3 stage EVO Shifters. All are made from 4140 steel.
Short Hex: Extends 2.00" from Outside the Gearbox
2 Stage EVO Shifter Short Hex Output Shaft (am-3498)
3 Stage EVO Shifter Short Hex Output Shaft (am-3520)
AM14U Family Hex Shaft: Extends 3.75" from Outside the Gearbox
2 Stage EVO Shifter AM14U3 Hex Output Shaft (am-3499)
3 Stage EVO Shifter AM14U3 Hex Output Shaft (am-3522)
Long Hex: Extends 5.00" from Outside the Gearbox
2 Stage EVO Shifter Long Hex Output Shaft (am-3500)
3 Stage EVO Shifter Long Hex Output Shaft (am-3523)
Short Keyed 1/2" dia. with 1/8" keyway: Extends 2.00" from Outside the Gearbox
2 Stage EVO Shifter Short Keyed Output Shaft (am-3501)
3 Stage EVO Shifter Short Keyed Output Shaft (am-3521)