In automotive transmission applications, spur gears are typically replaced by helical gears.

　　In automotive drivetrain applications, spur gears are often replaced by helical gears. Compared with spur gears, helical gears and helical gearboxes offer the potential for smoother operation. Depending on the gear’s tooth profile, the teeth of a helical gear are cut at a distinct angle. Consequently, during operation, when two teeth begin to mesh, contact gradually initiates at one region of the tooth and persists until the gears are fully engaged. The most commonly used gears in power transmission are helical gears, which can also generate substantial axial thrust.

　　 Basic Knowledge of Helical Gear Reducer Operation

　　A spur gear set with a helix angle of 0° is technically classified as a helical gearbox. The helix angle typically ranges from 15° to 30°. It has been established that a 20° involute spur gear is the standard tooth profile. Spur gears with a 14½° involute were once common but are no longer the norm. The pressure angle of the teeth refers to the latter value. When engaging and disengaging, two teeth follow a single line of contact.

　　 Basic Knowledge of Helical Gear Reducer Operation

　　Only a single-tooth involute gear maintains a constant pressure angle throughout the engagement process. The primary tooth profile is highly advantageous, as it exhibits a theoretically stable transmission ratio even when the center distance is not precisely fixed. This is sometimes referred to as the fundamental principle of gear drives: the necessity of a constant transmission ratio.

　　The best way to understand a helical gear set is to imagine many identical spur gears made of paper, linked together so that each subsequent segment is offset slightly forward relative to the preceding one. For this arrangement to function, the mating gears must be staggered in opposite directions. Because they are mounted on parallel shafts, paired helical gears are invariably left-hand and right-hand.

　　Thrust is generated by heavy loads, whereas spur gear meshing does not produce thrust. Helical gear models require roller bearings or ball bearings capable of withstanding axial loads to accommodate such thrust forces.

　　 Advantages of Helical Gear Reducers

　　When examining the gear design again, it is easy to see how each layer of the spur gears gradually engages with its corresponding section, followed by contact from the next section, whereas helical gears achieve simultaneous contact across the entire tooth face. Because the spacing between teeth is greater, more teeth are in contact at any given time. Compared with spur gears, helical gearboxes transmit loads more smoothly. Consequently, they offer higher speed potential, quieter operation, and greater load-carrying capacity. The following are some advantages of helical gearboxes over other types of gearboxes:

　　Sizes: 030-040-050-060-080-100-125-140

　　Available versions: H – for motor couplings, IH – with input shaft, CH – with compact motor, PH – for motor couplings with flexible joints.

　　Housing with base feet, flange F or universal U

　　Power up to 45 kW

　　Gears that have undergone hardening and tempering exhibit a skiving or grinding tooth profile.

　　Gears with 1, 2, and 3 reduction stages

　　The reduction ratio ranges from 1.23 to 282.10.

　　Maximum torque: 8,000 Nm; maximum permissible radial load: 55,000 N

　　The housing is made of G200 gray cast iron, offering high strength and optimized through FEM analysis.

　　The load capacity is calculated in accordance with ISO 6336 and verified according to AGMA 2001.  

　　Coated with RAL 5010 blue epoxy polyester powder coating.

　　Accessories: output flange, check valve, fluororubber oil seal