Toyota Starter

The Gear Reduction starter is a compact
lightweight unit with high torque capacity.

The reduction gear is mounted on the same shaft as the pinion gear. Unlike the conventional starter, the magnetic switch plunger acts
directly on the pinion gear (not through a drive lever) to push the gear into mesh with the ring gear.

This type of starter was first used on the 1973 Corona MKII with the
4M, six cylinder engine. It is now used on most 1975 and newer
Toyotas. Ratings range from 0.8 KW on most Tercels and some older
models to as high as 2.5 KW on the diesel Corolla, Camry and Truck.
The cold−weather package calls for a 1.4 KW or 1.6 KW starter, while a
1.0 KW starter is common on other models.

The gear−reduction starter is the replacement starter for most conventional starters.

Clutch Operation:
1. During engine start, the starter pinion gear drives the engine’s
flywheel ring gear.
2. Once the engine fires, the ring gear almost instantly begins to turn
faster than the starter pinion gear. Over−speeding would damage
the starter motor if it were not immediately disengaged from the
pinion gear.
3. The clutch uses its wedged rollers and springs to disengage the
pinion shaft from the clutch housing (which turns with the motor
armature). This happens any time the pinion shaft tries to turn
faster than the clutch housing.

Ignition switch in ON:
1. Current no longer present at terminal 50," but the main switch
remains closed to allow current from terminal C" through the pull−in coil to the hold−in coil.
2. The magnetic fields in the two coils cancel each other, and the
plunger is pulled back by the return spring.
3. The high current to the motor is cut off and the pinion gear
disengages from the ring gear.
4. The armature has less inertia than the one in a conventional
starter. Friction stops it, so a brake is not needed.

Starter Motors - Construction

Armature coil wires − The coil wires in a PS starter armature are
square in cross−section.
• More compact winding than round cross−section wires
• Greater output torque

Surface commutator − The square shape of the armature conductors
allow the surface of the armature to act as a commutator.

Field coils − Conventional starters use field coils. PS type starters use
two types of permanent magnets instead:
• Main magnets
• Inter−polar magnets

The two types of magnets are arranged alternately inside the yoke.
• Work together to increase magnetic flux
• Allows shorter yoke


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