Automotive：Differential Gears

Functions and Roles

Functions and Roles

The differential gear is a part of the power transmission device. The driving force generated by an engine is transmitted to the tires through various types of bevel gears. Differential gear is representative of the automotive components that incorporate such bevel gears. The differential gear assembly absorbs rotational differences due to the direction change of the rotational axis drive and/or the rotational differences between the right and left wheels that lead to smooth cornering.
More Details

Types of differential gears

Differential carrier assembly （ floorboard suspended unit ）

Differential carrier assembly（floorboard suspended unit）

Vehicle models:
Used for front and rear axles.

Characteristics:
Achieved weight reductions by adopting aluminum for the carrier material.
Used in both RR (rear engine, rear-wheel-drive) four-wheel-drive vehicles and FF (front engine, front-wheel-drive) based four-wheel drive vehicles.
 

Hypoid gear set
Hypoid gear set

Vehicle models:
Used for the final decelerator and changing angle for all four-wheel drive vehicles.

Characteristics:
Converts rotation axis by 90°, and also offsets the torsion position relationship of the two gear axles. SHOWA's gears offer excellent gear strength and quiet operation.
This gear set offers high strength and excellent quietness.
 

Pinion shafts for differential gears
Pinion shafts for differential gears

Vehicle models:
Pinion shafts hold the gears inside the differential gear unit.

Characteristics:
Responds to a wide range of needs through various surface coating method corresponding to loads.
Products include titanium coating as well as nitriding, and QPQ pretreament
 

Viscous coupling
Viscous coupling

Characteristics:
If transmits torque through viscous fluid filled inside.
 

Transfer gear set
Transfer gear set

Characteristics:
Driving power is conveyed to the propeller shaft through a 90° transfer.
 

Differential gear assemblies for ATVs
Differential gear assemblies for ATVs

Vehicle models:
4WD ATVs

Characteristics:
Loaded with LSD (limited slip differentials) function, overall vehicle traversal is improved. Maturity has lead to the achievement of the reduction of the number of parts as well as major weight reductions.

SHOWA'S Approach

Durability, transmission efficiency, and quiet operation are required of drive train products. At SHOWA, we satisfy these requirements by utilizing various approaches from numerous perspectives, including optimization of shapes based on structural analysis and processing method selection. In particular, SHOWA is devoting its energies to research into new gear processing methods that will greatly improve hypoid gear performance and cost. One example is our face hob cutting. Our gears are quieter than face mill gears (used in approximately 80% of Japan's passenger cars), and we've also achieved processing cost reductions.