DE102016209262A1 - Adjustment device and adjustment method of an axial load in an aircraft engine - Google Patents

Abstract

The invention relates to an adjustment device of an axial load (A) on at least one roller bearing (1) designed as a fixed bearing in an aircraft engine (100), characterized by at least one adjusting means for the axial load (A), which is dependent on an operating pressure, in particular from a chamber a compressor works. The invention also includes a setting method.

Description

The invention relates to an adjusting device for adjusting the axial load in an aircraft engine with the features of claim 1 and an adjustment method for the axial load on a rolling bearing in an aircraft engine with the features of claim 12.

Rolling bearings in aircraft engines are exposed to considerable loads, in particular axial loads, which are caused by axial forces on compressor stages and / or turbine stages. Setting to a certain value of the axial loads will increase the life of the rolling bearings. The use of gears in the shaft train of aircraft engines, the so-called power gearboxes in turbofan engines, the importance of rolling bearings and the adjustability of the relevant axial load is still increased.

Therefore, the object is to provide adjusting devices and adjustment methods for adjusting the axial load in an aircraft engine.

This object is achieved by an adjusting device with the features of claim 1.

In this case, at least one adjusting means for the axial load is used, which operates in response to an operating pressure, in particular from a chamber of a compressor.

In this case, the setting device has a data processing means with a mathematical model for the calculation of the axial load as a function of measurement data obtained on a roller bearing for the deformation, in particular the amplitude of a rollover signal, the temperature and / or the rollover frequency, the output value of the computer model being a manipulated variable, in particular represents the size of a valve opening and / or a pressure with which the axial load on the at least one roller bearing is adjustable to a desired value. As the sensor position rolls over, the amplitude and frequency of the deformation are measured. With these two inputs and the measured axial load, the coefficients of a function (e.g., polynomial) are estimated via a least-square estimate (least-squares minimization). From this, a function is formed which allows a determination of the axial load with these two input variables. Furthermore, a rotational speed of the aircraft engine is detected.

In particular, the computational model (e.g., an estimation model) may be obtained separately (i.e., offline) from actual use of the adjuster. So it is possible that e.g. Based on measurements and parameter investigations on an identical or similar rolling bearing, the calculation model is determined, which is then coupled in the form of software and / or hardware with setting device.

The output variables of the calculation model provide the axial force. This is the actual value of a control loop. The setpoint in the design of the bearing is determined. The control difference between setpoint and actual value determines the manipulated variable via a control algorithm.

The output value of the calculation model represents a manipulated variable. The manipulated variable in particular be the size of a valve opening and / or a pressure with which the axial load on the at least one roller bearing is adjustable to a desired value. By means of the computer model is a e.g. Control pressure can be calculated as a manipulated variable with which the axial load on the rolling bearing can be set to a nominal value (nominal value of the bearing load).

The controller with the calculation model thus indirectly establishes a functional relationship between the measured variables deformation and rollover frequency and the manipulated variable with which the axial force in the aircraft engine can be adjusted.

In this case, in one embodiment, the computational model may have a parameterized model, a functional relationship and / or a e.g. Lookup table. All of these possibilities can be efficiently implemented as software and / or hardware.

In one embodiment, a representative value for the deformation and rollover frequency of the at least one rolling bearing is the amplitude of the deformation resulting from a rollover signal. The detection of the representative value for the deformation of the at least one roller bearing may in one embodiment comprise a piezoelectric, a piezoresistive element and / or an acceleration sensor.

In a further embodiment, the adjusting device can also be used in a closed control loop, in which the measured data for the deformation, the temperature and / or the rollover frequency can be measured at the rolling bearing on which the axial load is adjustable. The data processing means and the computer model are then in a closed loop.

Thus, the manipulated variable can be determined by means of some input variables, with which an axial load on a rolling bearing is specifically adjustable. If, for example, the axial load is to be adjusted, then the control pressure can be selected specifically so that it as far as possible the other axial components compensated. This can also happen in the form of a control, so that this type of Axialkrafteinstellung takes place continuously.

In this case, the rolling bearing may be formed as a ball bearing or angular contact ball bearings. Typically, in embodiments, it is possible for the rolling bearing to be disposed on a shaft for a fan stage (e.g., in a turbofan engine) and / or a shaft for a compressor of the aircraft engine.

In one embodiment, a pressure control means comprises at least one pneumatic cylinder with which an axial force can be applied to a shaft. The pneumatic cylinder thus serves as an actuator for adjusting the axial load. Also, in one embodiment, the pressure control means comprises shaft seals, in particular labyrinth seals and / or brush seals. Thus, a targeted tracking of air for adjusting the control pressure can be effected.

Alternatively or additionally, in one embodiment, the pressure control means may automatically switch over from one operating condition to another depending on a deformation detected on the rolling bearing. Thus, e.g. in case of damage, an automatic adjustment of the axial load is made by e.g. is switched in an angular contact ball bearing of a destroyed pairing in a load reversal on a not yet damaged pairing of bearing surfaces.

The object is also achieved by a method having the features of claim 12. Embodiments of the methods and apparatus will be described with reference to figures. It shows

1 an aircraft engine having a transmission between a turbine stage and a fan stage and a controller;

2 an aircraft engine having a transmission between a turbine stage and a fan stage and a controller;

3 a schematic sectional view of an embodiment of a bearing of a shaft with a pressure control device;

4 a schematic representation of an aircraft engine with a transmission device and a pressure control device;

5 an exemplary representation of a calculation model for determining the axial load.

In 1 is an aircraft engine 100 in turbofan design with a rotation axis 11 schematically shown, in which case a transmission device 14 (power gearbox) between a low pressure compressor 15 and a fan stage 13 is arranged.

The aircraft engine 100 has an air inlet in the axial flow direction 12 , the fan stage 13 (here as part of the low pressure compressor 15 understood), the transmission device 14 , a high pressure compressor 16 , a combustion chamber 17 , a high-pressure turbine 18 , a low-pressure turbine 19 and an outlet 20 on. A housing 21 (Nacelle) encloses the aircraft engine 100 in parts and defines the air intake 12 ,

The aircraft engine 100 works in a basically known way, so that in the air inlet 12 entering air through the fan stage 13 is accelerated, whereby two air flows are generated: A first air flow is in the low-pressure compressor 13 guided within the core engine. A second air flow is through a bypass duct 22 led to generate the majority of the thrust. The air is not through the bypass duct 22 is guided, flows through the core engine.

The low pressure and high pressure compressor 15 . 16 in the core engine compress the local air flow, which for combustion in the combustion chamber 17 to be led.

The resulting hot combustion products relax in the high pressure and low pressure turbines 18 . 19 and drive these. Subsequently, the products of combustion pass through the air outlet 20 and provide another thrust share.

The high pressure turbine 18 drives over a high pressure shaft 24 the high pressure compressor 16 at. The low pressure turbine 19 drives over a low pressure wave 23 the low pressure compressor 15 with the fan stage 13 at. Thus, here is a two-shaft system.

The fan stage 13 is rotatable with the low pressure shaft 23 over the transmission device 14 connected.

The transmission device 14 is a reduction gear, with the speed of the Fanstufe 13 relative to the low-pressure turbine 19 and the low pressure compressor 15 can be reduced. Such an arrangement allows for higher speed and a more efficient low pressure turbine 19 and a slower rotating stage 13 with which a higher bypass ratio can be achieved.

By decoupling the speeds, it is possible to increase the speeds of the fan stage 13 and the low-pressure turbine 19 to optimize independently, even if doing so by the gear device 14 an additional weight is introduced.

Thus, in the aircraft engine shown schematically here 100 two waves 23 . 24 and a fan stage 13 before, each working with different speeds n _i .

This in 1 illustrated aircraft engine 100 is merely an example. Other aircraft engines 100 For example, have a three-shaft system or have another embodiment of the compressor 15 . 16 or turbines 18 . 19 on. Basically, an aircraft engine without Fanstufe 13 be designed as a turbojet engine.

In conjunction with the twin-shaft system is in 1 an example of a rolling bearing 1 shown as a fixed bearing, which is the high pressure compressor 16 opposite the high pressure shaft 24 outsourced. The rolling bearing 1 is designed here as angular contact ball bearings. Angular contact ball bearings are basically able to absorb both large axial and radial forces, wherein the adjustment of the axial loads, among other things positive on the life of the bearing 1 effect.

In the following, the resulting axial load A to be considered, which on the rolling bearing 1 acts (see 1 and 2 ). The following will be mainly on 3 Reference is made to a rolling bearing 1 a low pressure wave 23 is shown enlarged.

The axial force compensation on the rolling bearing 1 becomes particularly necessary as compressor 15 . 16 , and turbines 18 . 19 , each on a common wave 23 . 24 are stored, cause different levels of axial forces, which also also have in opposite directions (compressor 15 . 16 introduce a force forward, turbines 18 . 19 a force to the rear), so that always a - usually forward - resulting axial force A remains, including the rolling bearing 1 must be recorded. The amount of this resulting axial force A is otherwise not constant, but changes with the operating state.

In addition to the through compressor 15 . 16 and turbines 18 . 19 axial forces generated, Axiallastkomponenten by different air pressures and air currents (eg sealing air for sealing oil-lubricated bearing) is effected on the rotor disks of the compressor 15 . 16 and turbines 18 . 19 issue.

In the 1 and 2 Embodiments are shown in which a controller ( 1 ) or a control for adjusting the axial load A can be used.

In the control according to 1 becomes a data processing means 30 with a calculation model 31 for the calculation of the axial load A as a function of measurement data obtained for a deformation on a roller bearing, in particular the amplitude of a rollover signal (see, for example, US Pat 5 ), the temperature and / or the rollover frequency used. Input values for the calculation model 31 may also be the speed, the altitude and / or the speed.

The output value of the data processing means 30 is a manipulated variable (ie a control signal), here a control pressure, eg via a 1 and 2 not shown valve device is abandoned. Constructive designs for adjusting means are in 3 and 4 shown.

With the manipulated variable, which in particular represents the size of a valve opening and / or pressure, the axial load A is on the at least one rolling bearing 1 adjustable to a setpoint.

In 2 is an analog adjusting means shown with a closed loop, in principle to the description of the 1 Reference can be made.

To set to a setpoint of the axial load A on one of the bearings 1 , The closed-loop embodiment has a means for detecting (in particular measurement) a representative value for a deformation d of the rolling bearing 1 on. Such a representative value for the deformation d can, for example, from the amplitude of the rollover signal of the rolling bearing 1 be won. The greater the amplitude of the rollover signal, the greater the deformation d. The amplitude can be recorded, for example, by a piezoelectric element or an acceleration sensor attached to the rolling bearing 1 are arranged.

Furthermore, it becomes a means 60 for detecting (especially measuring) a rotational speed n of the aircraft engine 100 intended. This may be, for example, the speed n _{1 of} the low pressure shaft 23 act.

In an aircraft engine without reduction gear finds an axial load balance between fan and turbine stat. If one uses a reduction gear, then this axial load balance is "broken". Therefore, between the reduction gear and the turbine to absorb large axial forces.

The values for the deformation d and the speed n provide input values for a computer model 31 in a data processing means 30 , as a microcomputer eg in the engine 100 is arranged. Of Further uses the computer model 31 in the data processing means 30 at least one value for a pneumatic pressure p ₁ , p ₂ inside the aircraft engine 100 ,

In 5 is an example of a calculation model 31 in which an axial force (ie as an estimated axial force) can be calculated from two input variables (cage frequency and amplitude variable).

The computer model 31 can from these values the resulting axial load A on the rolling bearing 1 to calculate. It also calculates a control pressure p _control , inside the aircraft engine 100 can be adjusted so that the axial load A on the rolling bearing 1 corresponds to a predetermined setpoint or is set as part of an optimization calculation.

In 3 is shown that the data processing means 30 receives the input values for the deformation d, the speed n and pressures p1, p2. From this, the computer model calculates the control pressure p _control , with which, for example, the axial force A can be set.

With reference to the 2 For example, the control pressure p _control may be controlled by a pressure _control device 40 (Shown here only schematically.) Targeted in the context of a control on the downstream side of a rotor disk 25 be built, ie lowered to counteract the upstream axial force A. Here, the pressure p _{2 would} be lowered accordingly. The adjustment of pressures inside aircraft engines 100 for influencing the axial loads A is basically known. Here it is essential that different data, such as the deformation d and the speed are used in a computer model to determine the manipulated variable p _control .

In 4 an embodiment is shown in which a rolling bearing 1 in connection with a transmission device 14 (please refer 1 and 2 and the description in question). In such an embodiment, the fan stages are 13 and the here symbolically represented turbines 18 . 19 no longer directly connected. Therefore, high axial forces A on the rolling bearings 1 be caught.

In 4 has the pressure control device 40 a pneumatic cylinder 41 on, its cylinder 41 firmly with a low pressure wave 23 connected is. In the cylinder becomes a closed pressure chamber 43 through the movable piston matching the cylinder 42 educated. The calculated value for the control pressure p _control can now be used to _control the pressure in the pressure chamber 43 to be set so that the axial force A on the bearing, for example, is smaller. Thus, a controlled adjustment of the resulting axial force A via the load detection (ie the deformation d) takes place on the rolling bearing 1 ,

The adjustability of the axial load A can also be used in a different context.

The detected deformation d at the rolling bearings 1 can in known manner information about damage to the bearings 1 give. If, for example, in a double-row angular contact ball bearing 1 due to a determined deformation d damage can be detected, then the on the rolling bearing 1 acting axial load A can be adjusted so that at least a short-term operation of the aircraft engine 100 is possible. Also, by the pressure control device 40 a fail-safe setting can be made, so that automatically an axial load is set, which is typical for cruise, for example.

In 5 is shown a functional context, the so and possibly with other contexts part of a computational model 31 can be. Here, the dependence of the axial force on the amplitude size of the rollover signal (measured in V) and the cage frequency (measured in Hz) is shown. With increasing amplitude size and cage frequency, the axial force increases.

Such relationships can be measured in advance and then prepared appropriately, eg as a value table, in the calculation model 31 be deposited.

LIST OF REFERENCE NUMBERS

1

roller bearing

11

Rotary axis of the aircraft engine

12

air intake

13

fan stage

14

transmission device

15

Low-pressure compressor

16

High-pressure compressors

17

combustion chamber

18

High-pressure turbine

19

Low-pressure turbine

20

outlet

21

casing

22

Bypass duct

23

Low pressure shaft

24

High pressure shaft

25

rotor disc

30

Data processing means

31

computer model

40

Pressure control device

41

pneumatic cylinder

42

Piston of the pneumatic cylinder

43

pressure chamber

50

Means for detecting a deformation of the rolling bearing

60

Means for detecting a rotational speed of the aircraft engine

100

Jet Engine

d

Deformation of the rolling bearing

_i

Speed of a shaft i (here i = 1, 2, 3) in the aircraft engine

p

pneumatic pressure in the aircraft engine

Claims (12)

Adjustment device of an axial load (A) on at least one bearing designed as a fixed bearing ( 1 ) in an aircraft engine ( 100 ), characterized by at least one adjusting means for the axial load (A), which operates in dependence on an operating pressure, in particular from a chamber of a compressor. Adjusting device according to claim 1, characterized by data processing means ( 30 ) with a calculation model ( 31 ) for the calculation of the axial load (A) as a function of measured data obtained for a deformation on a roller bearing, in particular the amplitude of a rollover signal, the temperature and / or the rollover frequency, wherein the output value of the mathematical model ( 31 ) represents a manipulated variable, in particular the size of a valve opening and / or a pressure with which the axial load (A) on the at least one rolling bearing ( 1 ) is adjustable to a desired value. Adjustment device according to claim 2, characterized in that the calculation model ( 31 ) has a parameterized model, a functional relationship and / or a look-up table. Adjusting device according to at least one of the preceding claims, characterized in that a representative value for the deformation (d) of the at least one roller bearing ( 1 ) is the amplitude of deformation (d) resulting from a rollover signal. Adjustment device according to claim 4, characterized in that the means ( 50 ) for detecting the representative value for the deformation (d) of the at least one roller bearing ( 1 ) comprises a piezoelectric element, a piezoresistive element and / or an acceleration sensor. Adjustment device according to at least one of the preceding claims, characterized in that the measurement data for the deformation, the temperature and / or the rollover frequency on the roller bearing ( 1 ) are measurable, on which the axial load (A) is adjustable. Adjusting device according to at least one of the preceding claims, characterized in that the rolling bearing ( 1 ) is designed as a ball bearing or angular contact ball bearings. Adjusting device according to at least one of the preceding claims, characterized in that the rolling bearing ( 1 ) on a shaft ( 23 . 24 ) for a fan stage ( 13 ) and / or a wave ( 23 . 24 ) for a compressor ( 15 . 16 ) of the aircraft engine ( 100 ) is arranged. Adjustment device according to claim 8, characterized in that a pressure control means ( 40 ) comprises at least one pneumatic cylinder, with which an axial force on the shaft ( 23 . 24 ) can be applied. Adjustment device according to claim 9, characterized in that the pressure control means ( 40 ) Shaft seals, in particular labyrinth seals and / or brush seals comprises. Adjustment device according to claim 9 or 10, characterized in that the pressure control means ( 40 ) depending on one of the rolling bearing ( 1 ) determined deformation (d) automatically makes a switch from one operating state to another. Adjustment method for an axial load (A) on at least one roller bearing ( 1 ) in an aircraft engine ( 100 ), characterized by a) a mathematical model ( 31 ) for the calculation of the axial load (A) as a function of measured data for the deformation, in particular the amplitude of a rollover signal, the temperature and / or the rollover frequency, obtained in a roller bearing, in a data processing means ( 30 b) during operation of the aircraft engine ( 100 ) the data processing means ( 30 ) a manipulated variable as the output value of the computational model ( 31 ), wherein the output value in particular represents the size of a valve opening and / or a pressure with which the axial load (A) on the at least one rolling bearing ( 1 ) is set to a desired value.

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