The main gearbox of the helicopter

IPC classes for russian patent The main gearbox of the helicopter (RU 2065381):

B64D35/06 - the propellers or rotors being counter-rotating

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(57) Abstract:

The invention relates to aircraft and solves the problem of simplification of construction of the main gearbox of the helicopter, improve reliability and extend the service life of his work. The main gearbox of the helicopter has two docking station connection shaft of the free turbine of the engine with the input shaft of the main gear with the support of each engine to the gearbox housing. Two symmetrical kinematic chain composed of a series connection of a freewheel, conical and cylindrical steps. Wheels are located on one straight line passing through the center of summary cylindrical wheel rims which are made on the bearings and the hub is made with the possibility of axial and radial movement relative to the ring gear. The lower bearing of the shaft of the lower rotor and the upper bearing of the shaft of the upper rotor is made in the form of angular contact bearings. The attachment points of the main gear to the fuselage is made in the same plane on the housing of the main gearbox. Box actuator is made of two parts, between which is placed the mount Assembly control bearing screws helicopter. 4 Il.

Isoetes main gear coaxial-rotor helicopter Ka-25K, comprising a housing with mount gearbox to the fuselage, consisting of an upper, a middle portion and a pallet, two of the input shaft associated with each shaft of the free turbine of the engine, two coaxial, counter-rotating shaft of the lower and upper main rotors of the helicopter, mounted on bearings, planetary-closed mechanism comprising two output link associated with the shaft bearing screws, and the input link, consisting of two Central wheels with outer teeth summarizing cylindrical wheel, consisting of a ring gear and hub associated with the input element of the planetary-closed mechanism, two symmetrical kinematic chain from the input shaft to the summing cylindrical wheels, each including cylindrical, conical gear and freewheel, the attachment points of units to control bearing screws and a box of actuator units for the maintenance of the helicopter (Mechanical transmission helicopters /Ed. by C. N. Kestelman. M. 1983, 107-109 C., Fig. 3.39 and 3.40).

A disadvantage of the known main gearbox is its complexity in a large number of steps, poor layout, the consequence of which was the need to use what esteem which resulted in an additional load on the output of the speed reducer and the increase in the mass of the gearbox, the irrational choice of the type of bearings and their placement in the gearbox, resulting in the complexity of the design of the supports, loading the lower part of the shaft of the upper screw efforts stretching, and as a result, the increase in the mass of the specified shaft.

A major shortcoming of the gearbox is that the attachment points of the gearbox to the fuselage are located on the upper housing and the lower, which leads to the situation that requires the use of rod elements mounting the gearbox to the fuselage, which also complicates the design of the gearbox and increases its weight.

In addition, due to the fact that some of the units to control the bearing screws located separately from the main gearbox, complicated control scheme bearing screws (not "hard" link in the control circuit bearing screws), which leads to non-nominal modes of bearing screws and, as a consequence, vibrations and dynamic loads on the main gearbox, which reduces the reliability of his work and life.

Cannot be considered as optimal and execute a single box of actuators known in the gearbox due to the fact that, in addition to technological difficulties of its implementation, there are op">

All of these disadvantages of the known main gearbox lead to the complication of its design, the increase in mass and decrease in reliability in the operation of the helicopter, and also to a lowering of the efficiency of the mechanism of the main gearbox and increase its value.

The aim of the invention is to simplify the design of the gearbox, reducing its weight, increase its reliability and lifetime.

This objective is ensured by the fact that the main gearbox of a helicopter, comprising a housing to mount the gearbox to the fuselage, consisting of upper, middle parts and pallet, two of the input shaft associated with each shaft of the free turbine of the engine, two coaxial, counter-rotating shaft of the lower and upper main rotors of the helicopter, mounted on bearings, planetary-closed mechanism comprising two coaxial output link associated with the shaft bearing screws, and the input link, consisting of two Central wheels with outer teeth summarizing cylindrical wheel, consisting of a ring gear and hub, associated with the input element of the planetary-closed mechanism, two symmetrical kinematic chain from the input shaft to summarise cylindrically units to control bearing screws and a box of actuator units for the maintenance of the helicopter, characterized in that the main gear is equipped with two docking ports for the connection of the shaft of the free turbine of the engine with the input shaft of the main gear with the support of each engine to the gearbox housing, each of the two symmetric kinematic chain consists of a series connection of a freewheel, conical and cylindrical-speed, wheels with cylindrical treads located on one straight line passing through the center of summary cylindrical wheel rims which are made on the bearings and the hub of it is made with the possibility of axial and radial movement relative to the specified gear the lower bearing of the shaft of the lower rotor and the upper bearing of the shaft of the upper rotor is made in the form of angular contact bearings, the attachment points of the main gear to the fuselage is made in the same plane on the housing of the main gearbox, and on the upper part of the body of the box actuators made of left and right parts, between which is placed the mount Assembly control bearing screws helicopter.

In Fig. 1 shows a General view of the main gear box of Fig. 2 cross section a-f in Fig. 1, in Fig. 3 cross-section B-B in Fig. 1, and Fig. 4 vny reducer includes a housing 1 with nodes 2 mounting the gearbox to the fuselage (not shown), consisting of an upper part 3, the middle part 4 and tray 5, the two input shafts 6, which via connecting node 7, consisting of couplings 8 connecting the input shaft 6 to the shaft of the free turbine (not shown), and supports 9 of the engine on the gearbox housing 1 (Fig. 2 shows an example implementation of such support in the form of spherical surfaces on the motor and gearbox), two coaxial, counter-rotating shaft 10, and 11 of the lower and upper main rotors of the helicopter, mounted on bearings, and the lower bearing 12 of the shaft 10 of the lower rotor and the upper bearing 13 of the shaft 11 of the upper rotor is made in the form of angular contact bearings, perceiving, respectively, the thrust from the lower and upper bearing screws so that the perception is concentrated in one area of the upper part 3 of the housing 1 gearbox, planetary-closed mechanism 14, includes two output coaxial link 15, 16 connected by a shaft bearing screws 10, 11, respectively, and the input element 17 consisting of two Central wheels 18, 19 with external teeth. Planetary-closed mechanism comprises a planetary range and enumeration. The planetary series includes a Central wheel 18 with outer teeth, drove 20 satellites and Scovie satellites 22, installed on the axes, are accommodated in the housing 1, and the Central wheel 23 with internal teeth. Wheels 21 and 23 are interconnected and the output element 15, and the shaft 10 of the lower rotor. Drove 20 is connected with the output element 16 and the shaft 11 of the upper rotor.

The main gear also contains a summing cylindrical wheel 24, consisting of a ring gear 25 on the supports 26, the hub 27. Gear 25 is connected with the possibility of axial and radial movement relative to each other with the hub 27, and the latter with the Central wheels 18, 19. Such "floating" connection, allowing you to self gears in the mechanism, it is necessary to equalize the load on satellites and on the length of the teeth of wheels.

From the input shaft 6 to sum cylindrical wheel 24 has two symmetric kinematic chains, each including an overrunning 28, conical step 29, consisting of the drive wheel 30 and the follower 31, the cylindrical stage 32, consisting of the drive wheel 33 and one summarizing the cylindrical wheel 24. Wheels 33 are located on one straight line passing through the center totalizer wheels 24.

The main gearbox has a box of actuator units, OBS and right 35 boxes and placed on the upper part 3 of the housing 1, not only due to ease of maintenance, but also, primarily, to ensure that each of its parts (left and right) to be independent from each other on the drive shaft for rotation duplicated units (generators, pumps, etc), and also to use high-speed input shaft 6 to drive the high-speed machines, generators, fans, etc) with a minimum number of steps.

Between the two parts of the box actuators 34, 35 posted by node 36 of the fixing unit control bearing screws (steering system including booster and elements of automation control). Rigid attachment of this unit to the housing of the gearbox allows you to "toughen" the control circuit bearing screws and thereby reduce dynamic loads on the elements of the gearbox and the nodes of its attachment to the fuselage.

Execution nodes 2 mounting the main gear to the fuselage in the same plane on the housing main gearbox allows you to place these sites for the greatest radius (in the middle part of the cylindrical stage gearbox with summarizing the wheel having the largest diameter in the gearbox).

Works main gearbox as follows.

When Zap the drink gearbox (through the coupling 8 of the docking station 7), the freewheel 28 this circuit is closed, passing the rotation of bevel circuit 29 (wheels 30, 31), cylindrical step 32 (wheels 33 and summarizing the wheel 24) and then to the planetary-closed mechanism 14, in which the flow of power from the engine is divided into the flow of power through brute force (wheel 19, satellites 22, the wheel 23 and the planetary series (wheel 18, drove 20 satellites, the wheel 21 and is transmitted to the shafts 10, 11 of the bearing screws. Thus the second input shaft 6 remains stationary (the corresponding freewheel 28 slips), and the remaining elements of the second symmetric chain rotate idle without transmitting power. When you start the second engine, the process described for the first circuit is repeated for the second kinematic chain. (Summarizing the cylindrical wheel 24 is the sum of the power from the two engines).

From the input shaft 6 are rotated, the drive shafts of the left and right boxes of the actuators 34, 35.

The advantages offered by the main gearbox in comparison with the known adopted for the prototype, the following:
1) fewer steps in the symmetric kinematic chains (two instead of three) when equal to the total transmission ratio;
2) rational is the " gear ratio for speed. In the planetary-closed mechanism and the cylindrical steps are implemented to the maximum possible ratio, and in the conical transmission is used, the optimum gear ratio, providing high efficiency and minimum dimensions and weight. The freewheel has a minimum mass, because it passes the minimum possible torque (engine torque);
3) the location of the leading cylindrical wheel 33 on a straight line passing through the center of summary cylindrical wheel 24, provides minimal efforts to support summarizing wheel 24 (efforts from the gear when the two engines with the same power are mutually destroyed due to the symmetry of the arrangement of the wheels);
4) performing a summation of the wheel 24 with a ring gear 25 on the supports 26 and connect it to the hub 27 by connection, providing axial and radial movement relative to each other (the so-called "floating" connection), allow the hub with minimal weight and size due to the fact that it only transmits torque (bending moment is perceived supports 26). In addition, the connection of the hub with the Central wheels 18, 19 with the outer working conditions gear wheels of the planetary-closed mechanism by self and balancing on satellites and on the length of the teeth;
5) lower shaft bearing lower bearing screw and the upper support upper rotor in the form of radial bearings simplifies support (instead of two bearings one) and decreases the weight of the shaft of the upper rotor below the specified support due to the fact that this part of the shaft is not subjected to tensile force on the thrust screw. In addition, the performance of these bearings allows you to focus on the thrust in one place, freeing from axial forces middle part of the body (the prototype of the bearing, the bearing axial force, is located in the lower part of the body);
6) the location of the attachment points of the gearbox in the same plane on the housing main gearbox allows power belt around the perimeter of the part of the body, which is summarizing the cylindrical wheel speed. Thus, these nodes are located at large radii and, therefore, perceive the bending load at the minimum node size, which reduces the mass of the gearbox (these nodes are made of a material, i.e., magnesium alloy, while excluding lugs on the housing for attachment points studs, steel studs and fasteners);
7) the presence of two Corot is and through the use of drive units from the input (high-speed) shaft of the gearbox;
8) placement on the upper part of the body of the mount Assembly control bearing screws (steering system) can increase the reliability and service life of the gearbox by increasing the "rigidity" of the management and reduction of dynamic loads.

Thus, all the listed advantages of the proposed main gear allow simplifying the design, reducing the weight of the gearbox, improving efficiency and resource and cost reduction. In addition, the proposed design of the main gearbox allows you to expand the layout capabilities of the gearbox and its modifications (due to the simplicity of changing the distance between the motors and their position relative to the main gearbox, the use of plug-in modules boxes drives).

The main gearbox of a helicopter, comprising a housing to mount the gearbox to the fuselage, consisting of upper, middle parts and pallet, two of the input shaft associated with each shaft of the free turbine of the engine, two coaxially opposite to the rotation shaft of the lower and upper main rotors of the helicopter, mounted on bearings, planetary-closed mechanism comprising two coaxial output link associated with vladicescu wheel, consisting of a ring gear and hub associated with the input element of the planetary-closed mechanism, two symmetrical kinematic chain from the input shaft to the summing cylindrical wheels, each including cylindrical, conical gear and freewheel, the attachment points of units to control bearing screws and a box of actuator units for the maintenance of the helicopter, wherein the main gear is equipped with two docking ports for the connection of the shaft of the free turbine of the engine with the input shaft of the main gear with the support of each engine to the gearbox housing, each of the two symmetric kinematic chain consists of a series connection of a freewheel, conical and cylindrical stages, with the driving wheels of the cylindrical treads located on one straight line passing through the center of summary cylindrical wheel rims which are made on the bearings and the hub of it is made with the possibility of axial and radial movement relative to the specified gear lower bearing shaft rotor and the upper bearing of the shaft of the upper rotor is made in the form of radial bearings, the nodes crepe is flanged at the top of the housing box actuators made of left and right parts, between which is placed the mount Assembly control bearing screws helicopter.