This Shark-4 Servo Gearbox is driven by the Hitec's flagship HSR-M9382TH brushless, titanium geared servo. This gearbox introduces a 4:1 external gear ratio in order to lessen the range while increasing the torque and precision four-fold. If this ratio doesn't suit your needs, be sure to check out the other Servo Gearbox options.
Having the servo mounted in the gearbox isolates the load to a steel hub-shaft that is supported in a pair of ball bearings to protect the servo from any axial loads. The gearbox opens up a world of mounting possibilities given the M4 threaded holes on each side which are on the grid pattern for compatibility throughout the goBILDA® system. The hub on the top of the gearbox provides threaded holes to fasten to, but you can also opt to fasten straight to the aluminum output gear using M4 hardware and standoffs or spacers. The 8mm REX bore of the hub-shaft can drive an 8mm REX shaft or act as a wire pass-thru.
If you’re not accustomed to using a servo gearbox, it’s just like a normal servo only larger. While the range and torque might be greater than the servos you’re used to, the control signal is identical. It will simply plug into an R/C receiver, an Arduino, Raspberry Pi, or REV controller. Furthermore, since the servo hasn’t been modified in any way, it is FTC legal!
This Servo Gearbox is available in both feedback mode, and continuous mode. In feedback mode, your signal controls the position. In continuous mode, your signal controls the speed and direction. Regardless of which you purchase, it can always be toggled to the other mode with a DPC-11 servo programmer.
The answer to this question is partially dependent on what you are using to control the servo that drives the gearbox. Click for a quick video explanation. As you can see below, a Servo Travel Tuner allows you to achieve maximum rotation, but it is just as useful to dial down the rotation to suit your needs.
With an Average Radio System:
1.125 Turns (405°)
Your average transmitter and receiver will output a relatively narrow PWM signal range.
Radio System + Travel Tuner:
1.75 Turns (630°)
Adding a Servo Travel Tuner to your radio system setup will allow you to achieve wide PWM signal ranges.
Wide Signal Controllers:
1.75 Turns (630°)
Controllers such as Arduinos, and Raspberry Pi servo hats can usually send a wide signal.
While we offer a variety of pre-made ratios, if you already own one of our Servo Gearboxes and want to change the ratio, here are the gears you will need to obtain the ratio you desire.
|Ratio||Servo Gear||Hub-Mount Gear|
|2:1||40T (2305-0025-0040)||80T (2302-0014-0080)|
|3:1||30T (2305-0025-0030)||90T (2302-0014-0090)|
|4:1||24T (2305-0025-0024)||96T (2302-0014-0096)|
|5:1||20T (2305-0025-0020)||100T (2302-0014-0100)|
|7:1||15T (2305-0025-0015)||105T (2302-0014-0105)|
|9:1||12T (2305-0025-0012)||108T (2302-0014-0108)|
|Voltage Range||6V - 8.4V|
|No-Load Speed (6.0V)||0.68sec/60° (14.7 RPM)|
|No-Load Speed (7.4V)||0.45sec/60° (17.8 RPM)|
|Stall Torque (6.0-7.4V)||1888 oz-in (136 kg.cm)|
|No-Load Current (6.0V)||260mA|
|No-Load Current (7.4V)||270mA|
|Stall Current (6.0-7.4V)||2700mA|
|Motor Type||Brushless DC|
|Direction with Increasing PWM Signal||Counter Clockwise|
|Max PWM Range||800-2200μsec|
|Travel per μsec||0.45°/µsec|
|Max Rotation||630° (1.75 Turns)|
|Deadband Width||1 μsec|
|Wire Length||300mm (11.81")|
|Connector Type||3-Pos TJC8 Servo Connector [MH-FC]|