DENSO Automotive OEM Products


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Engine Management
Starters


PS Starter
RA Starter

Starters

When the ignition switch is turned on, the starter, which is battery driven, rotates the engine’s crank shaft to start the engine. DENSO has been developing smaller, lighter, quieter starters that maintain high output. DENSO’s starters are optimal for any vehicle—from motorcycles to large trucks.

DENSO Technology - Leading the World
In 2001, DENSO introduced the world’s first PS* starter featuring a square conductor in the armature coil. The PS starter was 22 percent lighter and 14 percent shorter than the RA starter, and resulted in improved fuel efficiency and mountability in the vehicle.

* PS: Planetary Reduction Segment Conductor Motor

Operations

When the ignition switch is turned on, the pinion gear is pushed to engage with the ring gear. At the same time, the magnetic switch contact point is closed, and then the current flows into the motor. Accordingly, the armature rotational force is transferred to the engine’s ring gear through the pinion gear and starts the engine.

Technology Evolution

	F-Starter Unique structure with the pinion gear pushed through the drive lever. Spiral brush spring. Aluminum end frame.
	External-Gear Deceleration R-Starter World's first deceleration structure - Decreased the mass by half while maintaining the same output. Pinion direct-shift method improves environmental durability.
	External-Gear Deceleration RA-Starter High-speed motor with an improved deceleration ratio and a heat-resistant electric wire reduces the size and weight of the motor. Cold-forged spline reduces the size and weight of the magnetic switch.
	Internal-Gear Deceleration PS-Starter A rectangular conductor and surface commutator in the armature and a magnet between the main electrodes of the yoke reduces the size and weight of the starter. Combining the damper unit and the high deceleration ratio reduces the size and lowers driving noise.