RU2516090C2 - Lubrication system and helicopter rotor containing this lubrication system - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: invention relates to a lubrication system, in particular for a turbine or a drive of an aircraft. The lubrication system contains a drive to actuate a helicopter rotor, a lubrication pump, a lubrication fluid tank, a housing into which the drive member being lubricated is placed. The lubrication pump contains the first and the second stages. The first stage is made capable to compress lubrication fluid from the tank to deliver it to the mentioned member placed in the mentioned housing. The second stage is made capable to deliver lubrication fluid from the housing back to the tank. The second stage contains the first and the second rotors which are actuated by the first stage. The first stage contains at least the third rotor and the fourth rotor connected with the first and the second rotors, respectively. The housing accommodating the first and the second stages contains the first and the second parts which form corresponding axial end portions of the pump. The housing contains the first and the second plates which are located coaxially between the first and the second housing parts and hermetically separate the first and the second housing parts. The first housing part forms a cavity to which the first plate is faced and in which the first and the second rotors are accommodated. The second housing part forms a cavity to which the second plate is faced and in which the third and the fourth rotors are accommodated.

EFFECT: invention is aimed to provide for easy rotor replacement with concurrently compact pump design of smaller dimensions.

11 cl, 7 dwg

Description

FIELD OF THE INVENTION

The present invention relates to a lubrication system, in particular for a turbine or aircraft drive.

State of the art

It is known that lubricating pumps supply a certain number of jets of lubricating fluid under pressure to a lubricated element, for example, a drive or a turbine, and lubricating fluid is withdrawn from the housing in which said element is placed.

In particular, lubrication pumps of this kind include a first or feed stage, and a second or return stage.

The feed stage includes an inlet hydraulically connected to the reservoir of lubricating fluid, and an outlet hydraulically connected to a certain number of nozzles for creating jets of lubricating fluid under pressure, which are supplied to the lubricated element.

Thus, the feed stage guarantees a constant supply to the nozzles of the lubricating fluid under pressure, for supplying it to the lubricated element.

The return stage includes an inlet hydraulically connected to a hole in the housing of the lubricated element, and an outlet hydraulically connected to the reservoir.

In particular, the hole is made in the base of the housing in which the lubricated element is placed.

Thus, after lubricating the element, the lubricating fluid is pumped out of the base by means of a return stage and returned to the reservoir.

There is a need to prevent the accumulation or deposition of lubricating fluid around the hole in the base and to provide effective lubrication of the element, while at the same time reducing the number of mechanical parts, as well as the weight and size of the lubricating pump.

This is especially important for aircraft, where any reduction in weight leads to a reduction in power consumption and fuel consumption.

The closest analogue of the proposed lubrication system is the system disclosed in EP 1657442, publ. 05/17/2005, containing:

drive unit;

grease pump;

reservoir with lubricating fluid;

a housing in which the lubricated drive element is placed;

wherein the lubricating pump comprises a first stage having an inlet hydraulically connected to the lubricant reservoir and a supply opening hydraulically connected to a certain number of nozzles for supplying the lubricant to the housing and to said lubricating element, the first stage being adapted to compress the lubricant from the tank to a certain pressure for supplying to the specified element placed in the specified housing; and a second stage having an inlet hydraulically connected to an opening formed by the specified housing, and an outlet hydraulically connected to the reservoir, the second stage being adapted to supply lubricant from the housing back to the reservoir,

the second stage is a Roots type pump and contains first and second rotors that are rotatable in opposite directions to supply lubricant from the inlet to the outlet, the first and second rotors being driven by the first stage, the first the rotor contains a number of first protrusions, and the second rotor contains a number of second protrusions, the first and second protrusions having mating profiles that are in constant contact with each other a friend;

the first stage contains at least a third rotor and a fourth rotor, functionally connected, respectively, with the first and second rotors, and one of these third and fourth rotors is made to rotate when it is brought into action, the other of the third and fourth rotors;

wherein the pump further comprises

a first shaft connecting the first and third rotors;

a second shaft made with a fourth rotor on which a second rotor is mounted;

a housing in which the first and second stages are placed, containing the first and second housing parts, which form the corresponding axial end parts of the specified pump. A disadvantage of the known solution is the need for a complete replacement of the pump in case of failure or modernization of one of the stages.

Disclosure of invention

The objective of the present invention is to provide a lubrication system of such a design that will allow easy replacement of the rotors of the first and second stages of the pump, while at the same time compact design of the pump with smaller dimensions.

According to the present invention, this problem is solved by using a lubrication pump as part of a system having the features of paragraph 1 of the claims.

The lubrication system according to the invention contains:

a drive for actuating the rotor of the helicopter;

grease pump;

reservoir with lubricating fluid;

a housing in which the lubricated drive element is placed;

wherein the lubricating pump comprises a first stage having an inlet hydraulically connected to the lubricant reservoir and a supply opening hydraulically connected to a certain number of nozzles for supplying the lubricant to the housing and to said lubricating element, the first stage being adapted to compress the lubricant from the tank to a certain pressure for supplying to the specified element placed in the specified housing; and a second stage having an inlet hydraulically connected to an opening formed by the specified housing, and an outlet hydraulically connected to the reservoir, the second stage being adapted to supply lubricant from the housing back to the reservoir,

the second stage is a Roots type pump and contains first and second rotors that are rotatable in opposite directions to supply lubricant from the inlet to the outlet, the first and second rotors being driven by the first stage, the first the rotor contains a number of first protrusions, and the second rotor contains a number of second protrusions, the first and second protrusions having mating profiles that are in constant contact with each other a friend;

the first stage contains at least a third rotor and a fourth rotor, functionally connected, respectively, with the first and second rotors, and one of these third and fourth rotors is made to rotate when it is brought into action, the other of the third and fourth rotors;

wherein the pump further comprises

a first shaft connecting the first and third rotors;

a second shaft made with a fourth rotor on which a second rotor is mounted;

a housing in which the first and second stages are placed, containing the first and second housing parts, which form the corresponding axial end parts of the specified pump;

characterized in that the housing comprises a first and second plate, which are coaxially between the first and second housing parts and hermetically separate these first and second housing parts,

wherein the first body part forms a cavity to which the first plate faces and in which the first and second rotors are placed, and the second body part forms a cavity to which the second plate faces and in which the third and fourth rotors are placed.

Preferred embodiments are described in the dependent claims.

The first stage is a volumetric type pump.

The first and third rotors are made integrally with the first shaft, with a certain angular orientation.

The third and fourth rotors form the corresponding gears meshing with each other.

The first stage contains a first housing formed by a second housing part and a second plate, and the second stage comprises a second housing formed by a first housing part and a first plate, wherein the first and second protrusions, together with the second housing, form several chambers with a cyclically varying volume, ensuring transmission lubricating fluid inside said chambers from the inlet to the outlet.

The first and second protrusions have, at least in part, a profile of a cycloid shape that is in interaction with the lubricating fluid.

The pressure of the first stage is greater than the pressure of the second stage.

The first and second stages are made in such a way that during operation, the flow rate of the lubricant through the second stage is greater than the flow rate of the lubricant through the first stage.

During operation, the flow rate of the lubricant through the second stage is 1.5 times higher than the flow rate of the lubricant through the first stage.

The first shaft passes through the first and second plates.

The invention also relates to a rotor of a helicopter comprising a drive and a lubrication system according to a first aspect of the invention.

Brief Description of the Drawings

A preferred, non-limiting embodiment of the present invention is explained below by way of example, with reference to the drawings, where:

Figure 1 shows a perspective image of a lubricating pump according to the present invention, with a spatial separation of the parts;

Figure 2 shows an enlarged perspective view of part of the lubricating pump of Figure 1;

FIGS. 3 and 4 show perspective views of the rear and front of the pump of FIGS. 1 and 2, respectively;

Figure 5 shows a section along the line V-V in figure 3;

6 shows a section along the line VI-VI in figure 5;

Fig.7 shows a functional diagram of a system including a drive, a reservoir and a lubricating pump of Fig.1-6.

The implementation of the invention

The number 1 in Figs. 1-7 indicates a lubrication pump intended for installation in a lubrication system 2 (shown only in Fig. 7) for lubricating a mechanical assembly - in the shown example, this is actuator 3, which drives the rotor of the helicopter. 7 shows only the drive shaft of the rotor of the drive 3.

In particular, the system 2 comprises a reservoir 4 with a lubricant, in the example shown it is oil, for lubricating the actuator 3, and the reservoir 4 is made inside the housing 9 in which the actuator 3 is placed.

The drive 3 is known, and in addition to the said drive shaft, contains a certain number of mechanical elements that are not needed for a clear understanding of the essence of the present invention, and which are therefore not shown.

The pump 1 contains (Fig.7):

- a supply stage 5 having an inlet 6 hydraulically connected to the reservoir 4 and a supply opening 7 hydraulically connected to a certain number of nozzles 8 (only one is shown in FIG. 7) for spraying oil in the housing 9 of the actuator 3; and

a return stage 10 having an inlet 11 hydraulically connected to an opening 12 in an oil pan formed by the base 14 of the housing 9, and an outlet 13 hydraulically connected to the reservoir 4.

The supply stage 5 takes oil from the reservoir 4, compresses it to a predetermined pressure, which is set using a conventional valve (not shown), and feeds it to the nozzles 8, which, in turn, supply the corresponding oil jets to the drive shaft 3, in order to drive lubrication.

The oil that is collected in the oil sump after lubricating the actuator 3 is discharged using the return stage 10 and fed back to the tank 4, from where it is later taken out using the supply stage 5 and fed to the nozzles 8. In particular, the return stage 10 supplies the oil to the tank 4 through a certain number of holes 50 made in the housing 9, which are hydraulically connected to the outlet 13.

The pump 1 also includes a housing 20, which houses the feed stage 5 and the return stage 10.

In particular, the housing 20 (FIGS. 3, 4, 6, 7) is elongated along the axis A (shown only in FIGS. 3 and 4), and contains:

- two end housing parts 21, 22, which form the corresponding axial end parts of the housing 20; and

- three plates 23, 24, 25, which are located coaxially between the body parts 21, 22, and lie in planes perpendicular to the axis A.

With reference to FIG. 1, the plate 23 is coaxially between the body part 21 and the plate 24, the plate 24 is coaxially between the plates 23 and 25, and the plate 25 is coaxially between the plate 24 and the body part 22.

The housing part 21 is provided with a plate 23 facing the cavity, together with which it forms a housing 27 in which the return stage 10 is placed.

The housing part 22 is provided with a plate 25 facing the cavity, together with which it forms a housing 26 in which the feeding stage 5 is placed.

The plates 23, 24, 25 hermetically separate the housings 26, 27 with lip seals that prevent mixing of the oil flow in the feed stage 5 and the oil flow in the return stage 10.

The inlet 6 and the inlet 11 have a circular shape, and their axis of symmetry parallel to the axis A. In particular, the inlet 6 and the inlet 11 are aligned and are located on opposite sides relative to the plates 23, 24, 25.

The outlet 13 and the feed opening 7 also have a circular shape. In particular, the outlet 13 has an axis of symmetry perpendicular to axis A, and the supply opening 7 has an axis of symmetry inclined with respect to axis A.

The oil flow from the outlet 13 flows to the holes 50 through one or more heat exchangers 51, one of which is shown schematically in FIG. 7.

The supply opening 7 and the outlet 13 are located on the other side of the axis A relative to the inlet 6 and the inlet 11.

At the inlet 6 and the feed opening 7 of the feed stage 5 there are corresponding fittings 16, 17 (Fig. 7), which are hydraulically connected, respectively, to the tank 4 and the nozzles 8.

Similarly, at the outlet 13 of the return stage 10 there is a fitting 18 which is hydraulically connected to the reservoir 4.

The return stage 10 is preferably a Roots type pump, and comprises two rotors 31, 32 that rotate in opposite directions around the respective axes B, C in order to provide oil from the inlet 11 to the outlet 13. Both rotors 31, 32 driven by feed stage 5.

In particular, the rotors 31, 32 are placed inside the cavity formed by the body part 21, and each of them contains a corresponding number, in the shown example, three, the protrusions 33, 34.

The protrusions 33, 34 have mating profiles that are in constant contact with each other, and the axes B and C are parallel to each other and axis A.

The protrusions 33, 34 of the rotors 31, 32 and the housing 27 form a certain number of chambers 40 (only one is shown in FIG. 5), which move around the axes B and C. With each complete revolution of the rotors 31, 32, each chamber 40 successively passes the following states :

- a hydraulic connection with the inlet 11 for receiving the lubricating fluid from the hole 12;

- isolation from the inlet 11 and the outlet 13 for transmitting lubricant from the inlet 11 to the outlet 13; and

- a hydraulic connection to the outlet 13, as shown in figure 5, to return the lubricating fluid back to the reservoir 4.

In a state of isolation from the inlet 11 and the outlet 13, the volume of the chambers 40 is gradually reduced, as a result of which the lubricating fluid enclosed in them is subjected to some compression.

In particular, the protrusions 33, 34, located on the opposite side relative to the axes B and C and facing the inner surface of the housing part 21, have profiles of cycloid shape that interact with the lubricating fluid.

The supply stage 5 refers to volumetric pumps, that is, it advances the oil into the chamber, the volume of which gradually decreases in the area from the inlet 6 to the supply opening 7, whereby the oil pressure gradually increases in the area from the inlet 6 to the supply hole 7.

In the example shown, the supply stage 5 relates to gear type pumps, that is, it includes two gears 35, 36, which engage with each other and rotate in opposite directions around the respective axes B, C.

The gears 35, 36 and the housing 26 form a certain number of chambers (not shown) that move around the axes B and C, and each of which, when the gears 35, 36 are completely rotated, successively passes through the following states:

- a hydraulic connection to the inlet 6 for receiving the lubricating fluid from the reservoir 4;

- isolation from the inlet 6 and the outlet 7; and

- hydraulic connection with the outlet 7 for supplying lubricant to the nozzles 8.

In particular, in a state of isolation from the inlet 6 and the outlet 7, the volume of the chambers formed by gears 35, 36 is gradually reduced to compress the lubricating fluid enclosed therein to the pressure of the nozzle supply 8.

The gear 35 is made integrally with the shaft 37, which rotates around the axis B under the influence of the drive element, not shown in detail.

In particular, the shaft 37 passes through the plates 23, 24, 25 and has an end 38 that protrudes from the housing part 21 beyond the housing 20, and which is driven by the specified drive element.

In addition, the rotor 31 is mounted on the shaft 37.

Similarly, the gear 36 is made integrally with the shaft 39, on which the rotor 32 is mounted. The shaft 39 is elongated along the axis C, and passes through the plates 23, 24, 25.

In the shown example, the rotors 31, 32 are mounted, respectively, on the shafts 37, 39 using keys.

As a result, the rotation of the shaft 37 about the axis B causes the rotation of the gear 35 around the axis B.

The rotation of the gear 35 around the axis B causes, in turn, the rotation of the gear 36 around the axis C, and the rotation of the rotor 31 around the axis B.

And finally, the rotation of the gear 36 around the axis C causes, in turn, the rotation of the rotor 32 around the axis C.

Thus, the gears 35, 36 synchronize the rotation of the rotors 31, 32, that is, cause them to rotate around the respective axes B and C to transfer oil from the inlet 11 to the outlet 13.

In particular, gears 35, 36 are spur gears.

The dimensions of the supply stage 5 and the return stage 10 are selected so that during operation the flow rate through the return stage 10 is greater than the flow rate through the supply stage 5, which provides the maximum possible protection in any operating mode of the drive 3 from accumulation or deposition of oil in the oil sump of the drive 3.

Preferably, during operation, the oil flow rate through the return stage 10 is at least 1.5 times higher than the oil flow rate through the supply stage 5.

The pressure of the supply stage 5 is greater than the pressure of the return stage 10.

In particular, in the supply stage 5, the oil is compressed from a pressure of 1 bar to a pressure of 10 bar, while in the return stage 10, the compression of the oil flowing from the inlet 11 to the outlet 13 is negligible.

System 2 includes conventional filters and devices (not shown) that provide a high degree of aeration of the oil flow passing through the return stage 10, and deaerating the oil flow passing through the supply stage 5.

Under real operating conditions, the supply stage 5 takes oil from the tank 4, compresses it and feeds it to the nozzles 8, which, in turn, direct the jet of oil under pressure into the actuator 3 to lubricate it.

In particular, the free end 38 is driven into rotation by a drive element (not shown), and, in turn, causes the gear 35 and the rotor 31 to rotate about an axis B.

The rotation of the gear 35 around the axis B causes, in turn, the rotation of the gear 36 around the axis C.

When the gears 35, 36 rotate, oil is compressed through the inlet 6, which is then fed to the nozzles 8 through the feed hole 7.

After lubricating the actuator 3, oil accumulates in the base 14, from where it is diverted through the hole 12 using the return stage 10, which feeds it back to the reservoir 4.

The rotation of the gear 35 causes the rotor 31 to rotate about the B axis by the shaft 37, and the rotation of the gear 36 causes the rotor 32 to rotate about the C axis by the shaft 39.

Due to the rotation of the rotors 31, 32 in opposite directions with respect to each other, the oil entering through the inlet 11 is pushed into the chambers 40.

The chambers 40 rotate together with the rotors 31, 32, ensuring the supply of oil in the housing 27 to the outlet 13.

From there, the oil then flows into reservoir 4.

The advantages of the pump 1 according to the present invention become clear from the above description.

In particular, the applicant found that with a return stage 10 of the Roots type of pump, which is capable of transporting large volumes of lubricating fluid, pump 1 is particularly effective in preventing the accumulation and deposition of lubricating fluid inside the oil pan of the housing 9.

Since there is no need for two separate electric motors, one for the return stage 10 and the supply stage 5, pump 1 prevents the accumulation and deposition of lubricating fluid in the oil sump, using only a few components.

The rotation of the rotors 31, 32 around the respective axes B and C is synchronized by the rotation of the gears 35, 36, forming part of the feed stage 5, therefore, in the pump 1 there is no need to actuate two gears by a separate electric motor of the return stage 10. Each of the gears 35, 36 is functionally associated with the corresponding rotor 31, 32.

As a result, the weight and longitudinal size of the pump 1 is less than the total weight and size of the usual feed and return stages, working independently.

Finally, the cycloid shape of the protrusions 33, 34, as well as the fact that the rotors 31, 32 are driven by the feed stage 5, significantly reduce the stress caused by the relative sliding of the protrusions 33, 34, thereby reducing the cost and total weight of the rotors 31, 32.

Obviously, it is possible to make changes to the pump 1 described and shown here without deviating from the scope of protection defined in the claims.

In particular, the drive 3 can drive a turbine, and / or can be used in ground applications.

Claims (11)

1. A lubrication system comprising: a drive for actuating a rotor of a helicopter; grease pump; reservoir with lubricating fluid; a housing in which the lubricated drive element is placed; wherein the lubricating pump comprises a first stage having an inlet hydraulically connected to the lubricant reservoir and a supply opening hydraulically connected to a certain number of nozzles for supplying the lubricant to the housing and to said lubricating element, the first stage being adapted to compress the lubricant from the tank to a certain pressure for supplying to the specified element placed in the specified housing; and a second stage having an inlet hydraulically connected to an opening formed by the specified housing, and an outlet hydraulically connected to the reservoir, the second stage being adapted to supply lubricant from the housing back to the reservoir, the second stage being a Roots type pump and comprises first and second rotors that are rotatable in opposite directions to supply lubricant from the inlet to the outlet, first and second rotors are driven by the first stage, wherein the first rotor comprises a number of first projections, and said second rotor comprises a number of second projections, wherein the first and second projections have conjugate profiles, which are in constant contact with each other; the first stage contains at least a third rotor and a fourth rotor, functionally connected, respectively, with the first and second rotors, and one of these third and fourth rotors is made to rotate when it is brought into action, the other of the third and fourth rotors; wherein the pump further comprises a first shaft connecting the first and third rotors; a second shaft made with a fourth rotor on which a second rotor is mounted; a housing in which the first and second stages are placed, containing the first and second housing parts, which form the corresponding axial end parts of the specified pump; characterized in that the casing comprises a first and second plate, which are coaxially between the first and second casing parts and hermetically separate said first and second casing parts, wherein the first casing part forms a cavity facing the first plate and in which the first and second rotors, and the second body part forms a cavity to which the second plate faces and in which the third and fourth rotors are placed. 2. The system according to claim 1, characterized in that the first stage is a volumetric type pump. 3. The system according to claim 1 or 2, characterized in that the first and third rotors are made integrally with the first shaft, with a certain angular orientation. 4. The system according to claim 1 or 2, characterized in that the third and fourth rotors form the corresponding gears that are engaged with each other. 5. The system according to claim 1 or 2, characterized in that the first stage comprises a first body formed by a second body part and a second plate, and the second stage comprises a second body formed by a first body part and a first plate, wherein the first and second protrusions together with the second body, several chambers with a cyclically varying volume are formed, ensuring the transfer of lubricating fluid inside these chambers from the inlet to the outlet. 6. The system according to claim 5, characterized in that the first and second protrusions have, at least in part, a profile of a cycloid shape that is in interaction with the lubricating fluid. 7. The system according to claim 1, characterized in that the pressure of the first stage is greater than the pressure of the second stage. 8. The system according to claim 1, characterized in that the first and second stages are made in such a way that during operation the flow of lubricant through the second stage is greater than the flow of lubricant through the first stage. 9. The system of claim 8, characterized in that during operation, the flow rate of the lubricant through the second stage is 1.5 times higher than the flow rate of the lubricant through the first stage. 10. The system of claim 12, wherein the first shaft passes through the first and second plates. 11. The rotor of the helicopter containing the drive and lubrication system, characterized in one of claims 1 to 10.

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