Helicopter reduction gearbox

FIELD: transport.

SUBSTANCE: invention relates to aviation, specifically to helicopter transmission designs. Helicopter reduction gearbox includes case where following parts are located: bevel gear wheels connected with shafts of helicopter rotors, bevel gear forming engagements with mentioned bevel gear wheels of rotor shafts and connected with shaft mounted on tapered rolling bearings and with gear wheel fitted on this shaft. Inner rings of tapered bearings are fixed in axial direction relative to shaft, and outer rings are installed with thrust against case and sleeve beads in "tensioned" pattern. Outer bearing ring installed adjacent to crown of bevel gear has possibility of hard contact with case bead, and outer ring of the other bearing has possibility to rest on inner bead of sleeve. The latter is located in case hole with groove to interact with key connected with surface of the mentioned sleeve. Sleeve surface extends from case by its outside thread. Nut end can contact with reduction gear case from outside. The nut is made as closed cup with grooves in one of which tooth of locking device is placed. The locking device is attached to helicopter reduction gearbox case.

EFFECT: higher reliability and serviceability of reduction gearbox.

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The invention relates to the field of aircraft construction and can be used in the construction of helicopters, mainly with small weight and dimensions.

A known design of gears bevel gears, shafts mounted on tapered roller bearings containing a drive shaft with a pinion bevel gear and bearings installed schema "expansion" or "stretching", allowing adjustment of the clearances nuts, paired with a threaded section of the shaft, as in the named source in Fig. 12.6-B. The availability of easily deformable sleeve gives the possibility to indirectly estimate the magnitude of the gap torque wrench when tightening the nuts (Design units and parts of machines. / P. F. Dunaev, O. P. Lelikov. - M.: Higher school. 1998. - 447 S. - S. 194-197).

However, in the constructions known gearboxes there is no possibility of placing between the inner rings of the bearings of the hard parts, such as gears, without tightening the tolerances of the dimensions that affect the cost of the product and its reliability.

Known main gearbox of the helicopter containing the bevel gear transmission with gear, forming a mesh with two bevel wheels (Patent No. 2059535 EN. Publ. 10.05.1996 year).

However, in known main gearbox of the helicopter disadvantage is the need for security clearances required size is and by changing the thickness of the gasket between the hull parts, that eliminates the possibility of adjustment of clearances in the bearings without disassembly of the gearbox.

The famous passage of the main transmission of the vehicle, containing a bevel gear mounted on tapered roller bearings, housed in a glass, elongated in the radial direction, the engagement with the bevel wheel (Patent No. 2472646 EN. Publ. 20.01.2013,).

However, despite the fact that known for the invention of the Pets regulation clearances in the bearings by changing the thickness of the gasket between the glass and the cover on the control shaft, but in its design, there is no possibility of not discrete regulatory clearances in the bearings without additional finishing the thickness of the strip.

This device is the closest technical solution and selected as a close analogue.

The objective of the invention is the creation of a gearbox of the helicopter, mostly small with a small flight weight, structurally simple, low cost and high reliability and maintainability, the result of which is manifested in the possibility of discrete regulatory clearances in the bearings without additional finishing the thickness of the strip.

The problem is solved in that in the gearbox of a helicopter, comprising a housing with an inside bevel gears is mi, associated with the bearing shafts of the propellers of the helicopter, bevel gear forming engagement with these wheels associated with the shaft mounted on tapered roller bearings and posted on this shaft is a toothed wheel, and the inner ring tapered bearings fixed in the axial direction relative to the shaft, and the outer ring is supplied with an emphasis in shouldered body and sleeve according to the scheme "stretching", the outer ring of the bearing that is installed next to the ring gear bevel gear, has the ability to hard contact with the shoulder of the housing and the outer ring of another bearing rests on the internal shoulder of the sleeve, housed in the housing bore, having a groove for engagement with a key associated with the outer cylindrical surface of the named sleeve extending beyond the body of its external thread mating with the thread of the nut with its end resting in the gearbox housing from the outside and is made in the form of a deaf glass of grooves, one of which is placed the tooth retainer attached to the housing of the gearbox of the helicopter.

The present invention is explained detailed description and drawings, in which:

Fig.1 illustrates the design of the gearbox of the helicopter with a partial cut vertical plane, according to the invention;

Fig.2 shows a projection in the form of a, then W is as in Fig 1.

The gearbox of the helicopter assembled in housings 1 and 2, separated by a strip 3 into two compartments (Fig.1). In the left compartment are two identical bevel gear 4, forming two meshing with a bevel gear 5 made integral unit with the intermediate shaft on which it is placed: tapered roller bearing 6; a gear wheel 7; tapered roller bearing 8. The wheel 7 and the bearings 6 and 8 mounted inside the housing 2 by means of a glass 9 and the sleeve 10, an external thread which is screwed a nut 11, supported on the outer end of the housing 2 and is made in the form of a blind glass. The outer cylindrical surface of the sleeve 10 is placed associated key 12, a part corresponding to the groove B of the housing 2. By means of the nut 13 is fixed the inner rings of the bearings 6 and 8 and the gear wheel 7 in the desired axial position. The outer rings of these bearings are able support on the shoulder of the Cup 9 and the sleeve 10. The gap "δ" in the bearings provided by the respective position of the nut 11, is fixed by the stopper 21 by means of screws 22 (Fig.2).

Drive shaft gear 14 is connected with a cylindrical gear 15 with the possibility of engagement with the wheel 7 (Fig.1). The driving shaft of the gearbox 14 is installed in the housing 2 on bearings 16 by means of the cups 17 and 18. Conical wheels 4 are associated with the shaft upper bearing screw the (auto gaseous VNV) 19, coaxial, relative to the last set shaft rotor (HHB) 20.

Does the gearbox of the helicopter as follows.

Rotation of the drive shaft 14 is transmitted through the cylindrical gear gear 15 on the wheel 7 and further bevel gear bevel gear wheels 4, the driving shaft auto gaseous VNV 19 and the shaft HHB 20, rotating in different directions. Loads in the gearing gears are perceived by the bearings. In particular, the conical bearings 6 and 8 loaded effort, resulting in conical and cylindrical gear reducer.

It is known that the tapered roller bearings provide the necessary position of the axis of the shaft with sufficient accuracy only if the radial gap "δ" is equal to zero. This can be ensured during Assembly of the gearbox by rotating the nut 11, which shifts the sleeve 10 is required to eliminate the gap size. In the regulation of gap sleeve is held from rotation by a key 12, which groove B. If necessary, the bearings can be adjusted for tightness.

After the control is installed and fastened the latch 21.

Regulation gaps and heel contact in the conical transfer wheels 4 and the gear 5 is partly achieved by the selection of the strip 3 and similar strips in the bearings tapered subca who's 4 wheels.

In the process of regulation of the bearing clearance should be guided by the dependence of the rotation angle of the nut

$$\phi =\frac{\text{δ}\ast \text{360}}{\text{p}\ast \text{sinα}}$$

where "δ" is the initial value of the gap (mm);

p is the thread pitch of the sleeve 10 (mm);

α - angle contact bearing (°);

φ is the angle of rotation of the nut 11 (°) relative to the housing.

The proposed gearbox of the helicopter allows discrete control clearances in the bearings without additional finishing gasket thickness. Furthermore, the design of the proposed gear is simple, compact with a small flight mass.

The proposed gearbox of the helicopter has a low cost, high reliability, maintainability has with maintaining reliable operation of the bearing, the optimum position of the axes of the shafts and value gaps in the gearing of the transmission gearbox of a helicopter.

The gearbox of a helicopter, comprising a housing with an inside bevel gears associated with the shafts of the main rotors of the helicopter, bevel gear forming engagement with these wheels associated with the shaft mounted on tapered roller bearings and posted on this shaft is a toothed wheel, the rich inner ring tapered bearings fixed in the axial direction relative to the shaft, and the outer ring is supplied with an emphasis in shouldered body and sleeve according to the scheme "in the stretch, characterized in that the outer ring of the bearing that is installed next to the ring gear bevel gear, has the ability to hard contact with the shoulder of the housing and the outer ring of another bearing rests on the internal shoulder of the sleeve, housed in the housing bore having a groove for engagement with a key associated with the outer cylindrical surface of the named sleeve extending beyond the body of its external thread mating with the thread of the nut to its end, resting in the gearbox housing from the outside and is made in the form of a deaf glass of grooves, one of which is placed the tooth retainer attached to the housing of the gearbox of the helicopter.