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Pic. 31. Starter: 1. Anchor shaft; 2. Drive gear; 3. Gear bushing; 4. Freewheel roller; 5. Coupling cover; 6. Axis gear drive lever; 7. Starter cover on the drive side; 8. gear drive lever; 9. Anchor of the traction relay; 10. Traction relay housing; 11. Retracting winding of the traction relay, 12. Holding winding of the traction relay; 13. Traction relay rod; 14. Traction relay core; 15. Contact plate; 16. Traction relay cover; 17. Contact bolts; 18. End manifold; 19. Brush; 20. Brush spring; 21. Starter cover bushing; 22. Casing; 23. Coupling bolt; 24. Starter cover on the manifold side; 25. Armature winding; 26. Anchor core; 27. Stator winding; 28. Stator pole; 29. Starter housing; 30. Restrictive disk; 31. Driving ring; 32. Centering disc; 33. Buffer spring; 34. The outer ring of the freewheel; 35. Freewheel hub; 36. Restrictive ring of a course of a gear wheel; 37. Guide rod; 38. Plunger; 39. Starter; 40. Auxiliary starter relay; 41. Mounting block; 42. Ignition switch; 43. Generator; 44. Battery; I. Scheme of freewheel operation.
To spin the engine crankshaft up to the frequency at which it starts to work (i.e. to start the engine), starter type 29.3708 is used. He turns the crankshaft with a gear behind the flywheel ring gear. The starter power is 1.3 kW with a current consumption of 260 A.
The starter is a four-pole mixed-excitation DC motor with remote electromagnetic activation and a freewheel roller clutch. It consists of the following main parts; body 29, anchor with freewheel and drive gear 2, two covers 7 and 24 and traction relay 10. The body and covers are connected together by two tie bolts.
Inside the steel case 29, four steel poles 28 with excitation coils are fixed with screws. The housing, together with the poles and winding, is the starter stator. Three winding coils (serial) connected to the armature winding in series, and one (shunt) - in parallel. Therefore, the excitation of the starter is called mixed. It allows you to get a large torque in the inhibited state and a relatively low frequency of rotation of the armature at idle, which reduces wear on the bearing bushings and facilitates the operation of the freewheel.
An armature assembled on shaft 1 rotates between the stator poles. The armature core 26 is made of electrical steel plates pressed onto the middle part of the shaft. Along the circumference of the core there are longitudinal grooves, insulated with cardboard, in which there is an armature winding 25 made with copper tape. The ends of the winding are soldered to the collector plates and caulked for greater reliability. The armature shaft rotates in two ceramic-metal bushings. The rear sleeve 21 is pressed into the cover 24, and the front one is located in the clutch housing and the front end of the armature shaft enters it when the starter is installed in the clutch housing socket.
A feature of the starter 29.3708 is the end manifold 18, pressed onto the back of the armature shaft. Its use allowed to reduce the length and "mass" starter. In addition, the end collector contributes to a more stable and durable operation of the brush contact. The collector is made in the form of a plastic disk with copper plates embedded in it.
At the front end of the armature shaft there is a freewheel with gear 2 of the drive. When starting the engine, the clutch transmits torque from the armature shaft to the gear, and after starting it disconnects the gear and the armature shaft, and therefore the rotation of the flywheel is not transmitted to the shaft. As a result, the anchor is protected from "spacing" - damage due to centrifugal forces due to excessive rotational speed.
The coupling consists of an outer ring 34, riveted to the hub 35, and an inner ring, which is integral with the gear 2. In the grooves of the outer ring there are rollers 4 with springs, plungers 38 and guide rods 37. All of them, together with the outer ring and two thrust half rings rolled in a steel casing 5. The grooves of the outer ring have a variable width. In the wide part of the groove, the rollers can rotate freely, and in the narrow part they are wedged between the outer and inner rings of the coupling.
The traction relay is attached to cover 7. It is used to remotely control the activation of the starter. The relay closes the power circuit of the armature and stator windings, and also through lever 8 engages gear 2 with the flywheel crown. The relay is two-winding, has a retracting 11 and holding 12 windings wound in one direction. The beginning of the windings are soldered to the plug "50" on the relay cover. The end of the holding winding is welded to the relay flange (those. connected to "weight"), and the end of the retractor is connected to the lower contact bolt of the relay.
Starter operation
The starter is activated using an auxiliary relay type 111.3747-10 installed in the engine compartment. When the key is turned to position II ("Starter") contacts close "30" And "50" ignition switch, and voltage is applied to the winding of the auxiliary relay 40. It works, and current flows through its closed contacts into the windings of the starter traction relay. Under the action of this current, a magnetic force is generated (about 10-12 kgf), which retracts the armature 9 until it touches the core 14. The armature retracts and pushes the rod 13 with the contact plate 15, which closes the contact bolts 17. The dimensions of the rod are selected so that the contact bolts are closed even before the armature touches the core, and with a further stroke of the armature it is compressed spring of the contact plate, pressing it harder against the contact bolts. At the same time, the armature of the relay lever 8 moves forward the freewheel with gear 2 and engages it with the flywheel crown.
When the contact bolts are closed, the solenoid winding of the relay is de-energized, since both ends of it are connected to "a plus" battery 44. But since the armature of the relay is already drawn in, a relatively small magnetic flux is required to hold it in this position, which is provided by one holding winding 12.
Through the closed contacts of the traction relay, a current flows, feeding the stator and armature windings. The starter armature begins to rotate, and its rotation is transmitted through the screw splines to the hub 35 and the outer ring 34 of the coupling associated with it. Since rollers 4 are displaced by springs into the narrow part of the groove of the outer ring, they are wedged between the outer and inner rings of the coupling. Therefore, the torque from the armature shaft is transmitted through the clutch and gear to the flywheel crown.
After starting the engine, the flywheel begins to rotate the starter gear, and the speed of the gear begins to exceed the speed of the starter armature. Coupling inner ring (combined with gear) drags the rollers into the wide part of the groove of the outer ring 34, compressing the springs of the plungers 38. In this part of the groove, the rollers rotate freely without jamming, and the torque from the engine flywheel is not transmitted to the starter armature shaft.
When the starter is turned off, the auxiliary relay contacts open, and the power supply current for the starter windings follows the following path: "plus" battery - closed contacts of the traction relay - retracting 11, and then holding 12 windings of the traction relay - "weight". Since the direction of the current in the turns of the windings is opposite, the magnetic fluxes created by the windings compensate each other, and the relay core is demagnetized. The armature of the relay is pressed back to its original position by springs, and the relay contacts open, turning off the power to the armature windings and the starter stator.
At the same time, the armature of the traction relay with lever 8 moves the freewheel back and disengages the gear from the flywheel crown. The starter armature is braked by the forces of friction of the brushes on the collector, and it quickly stops.