13.1. Features of a design

The transfer case serves for change of size of torque and its distribution between forward and back bridges. The box has two transfers with transfer numbers 1,200 and 2,135. Forward and back bridges are given constantly and are connected by the interaxal differential redistributing torque between them depending on resistance to the movement of wheels. For increase in passability of the car the differential can be blocked, at the same time forward and back power shafts become rigidly connected among themselves (their frequencies of rotation are equal).

The transfer case fastens to a body floor on two rubber-metal arms. For adjustment of its situation concerning a flange of an intermediate shaft of an opening in arms are made oval, and between them and a body adjusting laying can be established. The order of centering of a box is described in the section Definition of the Reasons of Vibration and Centering of the Transfer Case.

Case details of the transfer case are cast from aluminum alloy and connected among themselves by hairpins and nuts. In the top part of a case the hatch closed by a stamped steel cover is executed. The forward cover is aligned on a case on two adjusting pins. Between covers and a case cardboard laying (at repair it is possible to use instead of them sealant laying) are located. All shaft (including the speedometer drive roller), and also rods of forks of gear shifting and blocking of differential are condensed with epiploons. In a forward cover two openings – aspic (it control) and drain are executed.

The leading shaft is established on two ball bearings in nests of a forward cover and a case. The internal ring of the forward bearing is clamped between a fillet of a shaft and a persistent ring самоконтрящейся a shaft flange nut. The internal ring of the back bearing is clamped between a fillet of a shaft and a persistent washer a nut on the back end of a shaft. The nut is stopped, pressing its edge into grooves on a shaft. The leading shaft is recorded from axial shift by an adjusting ring in a pro-point on an external ring of the back bearing and clamped between a case and a back cover.

On the leader to a shaft two leading gear wheels are located. The lobby (big) – the highest transfer, it freely rotates on the thermoprocessed shaft neck. Back (smaller) – the lowest transfer – freely rotates on the thermoprocessed plug installed on a shaft with a tightness. Gear wheels have two wreaths. Kosozuby (big) wreaths are in continuous gearing with the corresponding gear wheels of an intermediate shaft, and the gear shifting coupling at transfer inclusion connects to pryamozuby (small). The coupling moves on the nave which is rigidly put on shaft vents between the leading gear wheels. On average position of the coupling both transfers are switched off ("neutral") and torque from the engine is not transferred to wheels.

The intermediate shaft represents the block of two kosozuby gear wheels which are in continuous gearing with gear wheels of the leading shaft. The forward gear wheel, besides, is in gearing and with the conducted gear wheel fixed on the differential case.

The intermediate shaft rotates in two bearings: forward – roller, back – ball. From axial shift the shaft is recorded by an adjusting ring in a flute of an external ring of the back bearing which is clamped between a case and a back cover (as well as at the leading shaft). In a forward end face of a shaft the steel leading gear wheel of the drive of a speedometer is pressed. The conducted speedometer drive gear wheel – plastic, is established on the roller rotating in the speedometer drive case plug. The case is fixed on a forward cover of the transfer case.

On the VAZ-21214 car with the distributed injection of fuel in addition to the mechanical drive of a speedometer on the transfer case the speed sensor is installed.

The shaft of the drive of the forward bridge the forward end leans on the ball bearing in a case of the drive of the forward bridge fixed on a forward cover of the transfer case. The internal ring of the bearing is clamped between a fillet of a shaft and a persistent ring самоконтрящейся a shaft flange nut. From axial shift the bearing is fixed by the lock ring entering a flute of a case of the drive of the forward bridge. Back shlitsevy the end of a shaft is connected to a gear wheel of the drive of the forward bridge of differential. The Pryamozuby gear wheel on a shaft serves for blocking of differential. The design and installation of a shaft of the drive of the back bridge is similar, but on it there is no gear wheel.

The case of differential is executed demountable, both of its parts are connected by six bolts. The same bolts fix also the conducted gear wheel to the differential case. The last is established on two ball bearings. Internally the ring of the forward bearing is kept from shift by the expansion spring washer leaning on a lock ring in a differential case pro-point. The adjusting ring clamped between a forward cover of the transfer case and a case of the drive of the forward bridge enters a flute on an external ring of the bearing. Thus, the case of differential is kept from axial shift by the forward bearing; the back bearing is not fixed. On a forward part of the case of differential vents on which the blocking coupling moves are executed. At blocking inclusion the coupling connects to a gear wheel on a shaft of the drive of the forward bridge, connecting it to the differential case.

In openings of the case of differential the axis of satellites withheld by two lock rings is established. Under one of rings there is a spring washer interfering axial movement of an axis of satellites. Satellites (conic gear wheels) located on an axis are in continuous gearing with gear wheels of the drive of bridges. Between the case of differential and satellites basic washers are established. Their thickness is selected so that the axial gap of gear wheels of the drive of bridges did not exceed 0,10 mm, and the moment of resistance to rotation – 14,7 N. of m.

Control of the transfer case – manual, with the mechanical lever drive. The driver switches by the back lever transfers, to lobbies – includes blocking of differential. The design of drives of management of a box is similar. The lever shakes in the longitudinal direction on the axis established in arm eyes in front of the transfer case. For reduction of friction plastic plugs are inserted into an opening of the lever. The lower end of the lever enters a groove of a rod and is fixed by a figured spring. Other end of a rod is connected to a fork of the corresponding coupling (gear shifting or blocking of differential) and is stopped by a bolt. The rod at the exit from a box is condensed with an epiploon and protected from dust by a rubber corrugated cover. For fixing of the drive the ball clamp serves in the chosen situation — the sprung ball enters grooves on rods. On a rod of gear shifting their three — for "neutral", the highest and lowest transfers, on a rod of blocking of differential – two ("is included" and "switched off"). Will screw the switch closing a chain of a control lamp at inclusion of blocking of differential in a cover of the drive of the forward bridge.