Gear Design

Our company specializes in the design and development of all types of gears and gearboxes, differential axles, transfer cases. Birom provides engineering services as a subcontractor in the defense industry in Turkey and the leading companies in automotive industry such as Aselsan, Roketsan, Otokar, MKE, FNSS and Tümosan. Below are some work carried out.

Drive Train


A planetary differential transfer case is designed for Tümosan's Pusat vehicle, which performs torque distribution with double-speed (hi-low), 33% front axle and 66% rear axle. There is a parking brake at the exit of the transfer case. Oil cooling is realized thanks to the oil pump which is adapted on it

The change of gear is achieved by the pneumatic actuator. The planetary differential can be locked by a pneumatic actuator as well. The front and rear differential also have a pneumaticly lockable. The Wheel Hub, which is adhered to the independent suspension, has the CTIS system.

Wheel Hub


Ratio : 4

Max Input Torque: 7200Nm @ 100 dev/dak

Max Input Speed : 3250 rpm 2500 rpm

Transfer Case


Ratio : 1:1 High, 1:1.77 Low

Max Input Torque: 7500Nm @ 195 dev/dak

Max Input Speed : 3250 rpm



Ratio: 1.3

Max. Input Torque: 4500Nm @ 75 rpm

Max. Input Speed: 2500 rpm

Final Drive


The final drive system we designed for Otokars's Tulpar vehicle has a planetary structure and drives the vehical's pallet. It is designed to be used on right and left palette of the vehicle. In front of the planetry system, there is a helical gear pair. In this way, the connection distance and ratio needingsd are provided.

The amount of torque that the final drive can carry is 12,500Nm. Other technical features are as follows:

    Total Ratio: 3,340

    Max. Input Speed: 2,325 dev/dak

    Max. Input Torque: 5,000 Nm

    Transfer Cases


    Intermediate gearbox designed for electric vehicles consists of helical gears and differential gears. The helical gears provide silent driving at high speeds of 8,000 rpm.The differential located inside provides the speed difference between the wheels. By the locking system designed to the differential body, the vehicle can stop without slipping.

    Some of the technical features are as follows:

      Total Ratio: 8

      Max. Input Speed: 8,000 rpm

      Max. Input Torque: 40 Nm

      Planetary Gear Boxes


      BRM 7:1

      Ratio: 7:1

      Backlash: 1 arcmin

      Max. Acceleration Torque (Nm) : 143

      Max. Input Speed (rpm) : 6000

      Nominal Acceleration Torque (Nm) : 75

      Nominal Input Speed (rpm) : 3100

      Efficency : %97

      Operating Temperature : -40ºC, +65ºC

      Weigth : 4 kg

      BRM 10:1

      Ratio: 10:1

      Backlash: 1 arcmin

      Max. Acceleration Torque (Nm) : 35

      Max. Input Speed (rpm) : 6000

      Nominal Acceleration Torque (Nm) : 18

      Nominal Input Speed (rpm) : 4000

      Efficency : %97

      Operating Temperature : -40ºC, +65ºC

      Weigth : 1.5 kg


      Please contact us for other technical specifications and project requirements.