The starter anchor shaft type 5712.3708 transmits rotation to the drive shaft via a planetary gearbox. The planetary gears of the gearbox rotate on needle bearings.
The starter drive consists of a pinion and an overrunning clutch. The drive can move along the spiral splines of the drive shaft.
Starter parts 2109.3708: 1 - screw for fastening the protective cap; 2 - protective cap; 3 - retaining half ring; 4 - rear cover fastening nut; 5 - back cover; 6 - brush springs; 7 - brush guides (outer part); 8 - brushes; 9 - stator; 10 - anchor; 11 - drive lever; 12 - drive; 13 - limiting ring; 14 - retaining ring; 15 - drive lever axis; 16 - traction relay mounting screws; 17 - front cover; 18 - plastic cover sealing ring; 19 - tie rods; 20 - rubber plug; 21 - traction relay core; 22 - return spring; 23 - traction relay sealing ring; 24 - traction relay; 25 - thrust washer; 26 - adjusting washers
The traction relay is installed on the electric motor housing and is designed for remote switching of the large current consumed by the starter when starting the engine, and mechanical connection of the starter drive with the toothed ring of the engine flywheel. The relay coil has two windings, a pull-in and a holding one.
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When the ignition key is turned to position II ("starter"), voltage is supplied from the battery to the control terminal of the traction relay "50", and from it to both relay windings. Under the influence of the magnetic field, the metal core of the traction relay, overcoming the force of the return spring, is drawn into the coil. In doing so, it sets the starter drive lever in motion. The drive lever with its horseshoe-shaped fork extends the starter drive, engaging the drive pinion with the toothed ring of the engine flywheel. At the same time, the copper contact plate located in the plastic cover of the traction relay closes the contact bolts. Current begins to flow through the starter armature windings, the armature begins to rotate, starting the engine.
The negative terminal of the pull-in relay winding is connected to the "ground" through the starter armature windings (see diagram). After the contact bolts are closed, the current stops flowing through this winding and the traction relay core is held by only one winding, this allows for a reduction in the heating of the relay windings and a reduction in power consumption at the moment of engine start.
The overrunning roller clutch of the drive transmits rotation only in one direction - from the starter to the flywheel. After starting the engine, when the crankshaft speed increases sharply, the clutch protects the starter from destruction.
After the driver releases the ignition switch (lock), the control voltage stops flowing to the traction relay output; the electromagnetic field holding the anchor disappears. The drive lever, under the action of the spring, moves the starter drive back and disengages the drive pinion from the flywheel ring gear. At the same time, the power contacts that supply current to the starter motor windings open.
Warning! The starter is the most powerful consumer of electrical energy in the car. When starting the engine, the current consumed by the starter can reach more than 400 A. Therefore, all electrical connections between the battery and the starter must have reliable contact.