KR20200074473A - Method for measuring of static friction torque - Google Patents

Abstract

The present invention relates to a static friction torque measurement method. According to one embodiment of the present invention, the static friction torque measurement method, capable of measuring static friction torque working on a first specimen simulating a compressor and a second specimen simulating a turbine wheel, includes: a load working step of making a compression load work on the first specimen and the second specimen; a heating step of heating the first and second specimens; a temperature measurement step of measuring the temperature of the first and second specimens; a torque working step of making torque on the first and second specimens; a torque measurement step of measuring torque up to a moment when the first and second specimen slip; and a torque correction step of correcting the torque measured through the torque measurement step based on a distance from an external force working spot to the first and second specimens and a distance from the external force working spot to the torque measurement spot.

Description

Method for measuring of static friction torque}

The present invention relates to a static friction torque measurement technique. Specifically, the present invention relates to a technique for measuring static friction torque generated at a contact surface between a compressor and a turbine wheel of an aircraft gas turbine engine.

The gas turbine is a device that uses a Brayton cycle, and is a device that obtains the rotational force of the turbine from the flow of combustion gas.

In general, a gas turbine is composed of a compressor for compressing intake air, a combustion unit for mixing fuel and compressed air for combustion, and a turbine that is rotated by obtaining rotational force from high-pressure combustion gas.

The gas turbine may be employed in an engine system that uses the rotational power of a turbine, such as a vehicle, a ship, or an aircraft, as a driving force, or may be employed in a power generation system that uses the rotational power of a turbine to drive a generator.

At this time, the gas turbine may use an axial compressor or a centrifugal compressor to compress air.

On the other hand, the aircraft gas turbine may be assembled using a tie shaft of a centrifugal compressor and a centrifugal turbine for engine parts. In this case, the rotational torque of the centrifugal turbine is transmitted through the turbine-compressor contact surface. However, when slippage of the turbine-compressor occurs at the turbine-compressor contact surface, rotational torque, that is, the driving force of the turbine cannot be normally transmitted to the rotor assembly including the compressor. Therefore, in order to prevent slippage at the contact surface, a static friction torque above a reference is required, which is determined by Equation 1 below.

(τ = static friction torque, f = tie shaft clamping force, μ = static friction coefficient, r = contact surface radius)

At this time, when the tie shaft fastening force is designed to be larger than the actual required value, the load load of the product is increased. Conversely, when the tie shaft fastening force is designed to be smaller than the actual required value, slippage occurs at the turbine-compressor contact surface. Therefore, proper clamping force should be designed, and static friction coefficient prediction is required for this. However, since the static friction coefficient varies depending on factors such as material, temperature, surface condition, surface pressure, and foreign matter, it is difficult to predict without experimentation.

Therefore, if the static friction torque between the turbine and the compressor can be measured, the static friction coefficient of the contact surface can be predicted, and an appropriate tie-shaft fastening force can be designed. Appearance is required.

0001) Korea Patent Publication No. 2010-0106617

An object of the present invention is to accurately measure the static friction torque generated at a contact surface between a compressor and a turbine wheel by creating an environment identical to that of an actual aircraft gas turbine engine.

A static friction torque measuring method according to an embodiment of the present invention is a method for measuring static friction torque acting on a first specimen simulating a compressor and a second specimen simulating a turbine wheel, comprising: the first specimen and the agent 2 a load acting step of applying a compressive load to the specimen; A heating step of heating the first specimen and the second specimen; A temperature measurement step of measuring temperatures of the first specimen and the second specimen; A torque action step of applying torque to the first specimen and the second specimen; A torque measurement step of measuring torque up to the point at which the first specimen and the second specimen slip; And a torque correction step of correcting the torque measured in the torque measurement step by using a distance from an external force acting point to the first specimen and the second specimen and a distance from the external force acting point to the torque measuring point. .

In one embodiment, the heating step may heat the first specimen and the second specimen when the compressive load applied in the loading action step reaches a reference load.

In one embodiment, the heating step may heat the first specimen and the second specimen to a reference temperature.

In one embodiment, the torque acting step may apply torque to the first specimen and the second specimen when the temperature of the first specimen and the second specimen reaches the reference temperature.

In one embodiment, the torque measurement step may measure the torque from the time the torque is applied to the first specimen and the second specimen to the time when the first specimen and the second specimen slip.

In one embodiment, the torque correction step multiplies the torque measured in the torque measurement step by the distance from the external force acting point to the first specimen and the second specimen, and from the external force acting point to the torque measuring point. You can correct by dividing the distance of.

The present invention creates an environment identical to that of an actual aircraft gas turbine engine to measure static friction torque generated at a contact surface between a compressor and a turbine wheel.

Therefore, the present invention has an effect capable of accurately measuring the static friction torque generated at the contact surface of the compressor and turbine wheel of an actual aircraft gas turbine engine.

In addition, since the present invention measures the static friction torque using a torque wrench, there is an effect capable of quickly measuring the static friction torque.

1 is a cross-sectional view of a static friction torque measuring device for performing a static friction torque measuring method according to an embodiment of the present invention.
2 is a view showing a process of correcting the measured torque in the static friction torque measuring method according to an embodiment of the present invention.
3 is a flowchart sequentially showing a static friction torque measuring method according to an embodiment of the present invention.

Advantages and features of the present invention, and methods for achieving them will be clarified with reference to embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but may be implemented in various different forms, and only the embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the person having the scope of the invention, and the present invention is only defined by the scope of the claims. The same reference numerals refer to the same components throughout the specification.

Unless otherwise defined, all terms (including technical and scientific terms) used in the present specification may be used as meanings commonly understood by those skilled in the art to which the present invention pertains. In addition, terms defined in the commonly used dictionary are not ideally or excessively interpreted unless specifically defined.

The terminology used herein is for describing the embodiments and is not intended to limit the present invention. In the present specification, the singular form also includes the plural form unless otherwise specified in the phrase. As used herein, “comprises” and/or “comprising” does not exclude the presence or addition of one or more other components other than the components mentioned.

Hereinafter, a static friction torque measuring apparatus will be described with reference to FIGS. 1 and 2.

1 is a cross-sectional view of a static friction torque measuring apparatus for performing a static friction torque measuring method according to an embodiment of the present invention.

Referring to FIG. 1, the static friction torque measuring device 10 includes a base plate 1, a body structure 2, a bar structure 3, a first specimen 4, a second specimen 5, and a torque plate ( 6), upper plate (7), adapter (8), ceramic band heater (P01), bearing (P02), hydraulic cylinder (P03), torque wrench (P04) and torque correction unit (9).

The first specimen 4 is a specimen simulating a compressor which is one component of a gas turbine, and the second specimen 5 is a specimen simulating a turbine wheel that is one component of a gas turbine. That is, in the present invention, static friction torque is measured through a specimen that mimics the compressor and turbine wheel, which are actual components of a gas turbine. Therefore, the present invention can measure a static friction torque almost equal to the static friction torque generated between the compressor and the turbine wheel of an actual gas turbine.

The ceramic band heater P01 heats the first specimen 4 and the second specimen 5. Specifically, the ceramic band heater P01 increases the temperature of the entire first specimen 4 and the second specimen 5 by heating the first specimen 4 and the body structure 2. At this time, the ceramic band heater P01 heats the first specimen 4 and the body structure 2 until the temperature of the entire first specimen 4 and the second specimen 5 reaches a reference temperature.

On the other hand, the reference temperature refers to a temperature set to create the same environment as the operating environment of an actual aircraft gas turbine engine. For example, the reference temperature may mean 400°C. However, the reference temperature may be set to a temperature other than 400°C.

The bearing P02 is designed by minimizing friction so that the torque acted on the torque wrench P04 can be transmitted only to the first specimen 4 and the second specimen 5.

The hydraulic cylinder P03 exerts a compressive load on the first specimen 4 and the second specimen 5. Specifically, when the hydraulic cylinder P03 is operated, the bar structure 3 is pulled upward, and in response to this, the bottom surface of the hydraulic cylinder P03 acts on the load. In addition, the load applied by the bottom surface of the hydraulic cylinder (P03) is transmitted through the upper plate (7), the bearing (P02), the torque plate (6), the first specimen (4) and the second specimen (5) To act as a compressive load.

At this time, the compressive load applied to the first specimen 4 and the second specimen 5 can be calculated using the pressure value of the pump gauge formed in the hydraulic cylinder P03 and the effective cylinder cross-sectional area.

Meanwhile, the hydraulic cylinder P03 compresses the first specimen 4 and the second specimen 5 until the compressive load acting on the first specimen 4 and the second specimen 5 reaches a reference load. To act. At this time, the reference load means a load set to create the same environment as the operating environment of an actual aircraft gas turbine engine.

The torque wrench P04 applies torque to the first specimen 4 and the second specimen 5. Specifically, when the torque wrench (P04) is rotated, torque is transmitted to the first specimen (4) and the second specimen (5) through the adapter (8), and torque is applied to the first specimen (4) and the second specimen (5). Is working.

The torque wrench P04 measures torque from a point at which torque is applied to the first specimen 4 and the second specimen 5 to a point at which the first specimen 4 and the second specimen 5 slip. At this time, the torque wrench P04 may mean a torque wrench for inspection in which a dial gauge is formed. Hereinafter, for convenience of explanation, the torque wrench P04 will be described on the assumption that the torque wrench P04 is the inspection torque wrench.

At this time, the dial gauge formed on the torque wrench P04 is composed of two instructions. Specifically, the dial gauge is composed of an operating instruction that moves according to the working torque and a dependent instruction that moves in contact with the operating instruction. The dependent guideline moves in the increasing direction as the operating guideline when the working torque increases, but when the working torque decreases, the operating guideline remains stationary even if it moves in the direction in which the working torque decreases.

That is, since the dependent guide of the dial gauge indicates the maximum torque acting on the torque wrench P04, the dependent guide of the dial gauge formed on the torque wrench P04 includes the first specimen 4 and the second specimen 5 When it slips, it stops. Therefore, by reading the scale of the dependent guideline at the time when the dial gauge formed on the torque wrench P04 stops, the torque at the time when the first specimen 4 and the second specimen 5 slip, that is, static friction torque can be measured. Can.

The torque compensator 9 corrects the torque measured by the torque wrench P04. The reason for correcting the torque measured by the torque wrench P04 in the torque compensator 9 is, as shown in FIG. 1, the torque measured by the torque wrench P04 is the first specimen 4 and the second specimen ( This is because there is a predetermined error because it is a torque measured at a distance from 5). A detailed description thereof will be described with reference to FIG. 2.

2 is a view showing a process of correcting the measured torque in the static friction torque measuring method according to an embodiment of the present invention.

Referring to FIG. 2, the torque compensator 9 measures the torque T1 measured by the torque wrench P04 from the external force acting point (a) to the center point of the first specimen 4 and the second specimen 5 ( Correction is made using the distance (L1 + L2) to c) and the distance (L1) from the external force acting point (a) to the torque measurement point (b).

That is, the torque correcting unit 9 corrects the torque T1 measured by the torque wrench P04 using Equation 2 below.

At this time, F is an external force acting on the torque wrench P04, (L1 + L2) is the distance from the external force acting point (a) to the center point (c) of the first specimen 4 and the second specimen 5, L1 is the distance from the external force acting point (a) to the torque measuring point (b), T1 is the torque measured by the torque wrench (P04), T2 means the torque corrected by the torque compensator (9).

Accordingly, the present invention calculates the static friction torque of the first specimen 4 and the second specimen 5 by correcting the torque T1 measured in the torque wrench P04 by the torque compensator 9, through which The static friction coefficient of the contact surfaces of the first specimen 4 and the second specimen 5 is predicted.

On the other hand, the present invention uses a first specimen (4) and a second specimen (5) that mimics the compressor and turbine wheel as it is, and creates the same operating environment as the operating environment of the compressor and turbine wheel of an actual aircraft turbine gas engine ( Since the torque applied to the first specimen 4 and the second specimen 5 is measured by compression load, temperature, etc., it is possible to predict a value substantially equal to the static friction coefficient of the contact surface of the compressor and turbine wheel of an actual aircraft turbine gas engine. There will be.

Hereinafter, a method of measuring static friction torque according to an embodiment of the present invention will be described with reference to FIG. 3. In this case, descriptions of parts overlapping with those described with reference to FIGS. 1 and 2 will be omitted.

3 is a flowchart sequentially showing a static friction torque measuring method according to an embodiment of the present invention.

Referring to Figure 3, the static friction torque measuring method according to an embodiment of the present invention, first, the hydraulic cylinder (P03) from the first specimen (4) and the second specimen (5) compressive load to reach the reference load Until the load is applied (S101, S103).

Subsequently, when the compressive load applied to the first specimen 4 and the second specimen 5 reaches the reference load, the ceramic band heater P01 uses the first specimen 4 and the second specimen 5. It is heated until the reference temperature is reached (S105, S107).

Thereafter, when the temperatures of the first specimen 4 and the second specimen 5 reach the reference temperature, the torque wrench P04 is until the first specimen 4 and the second specimen 5 slip. The torque is applied to the first specimen 4 and the second specimen 5 (S109, S111).

Thereafter, when the first specimen 4 and the second specimen 5 slip, the torque wrench P04 is the torque at which the first specimen 4 and the second specimen 5 slip, that is, static friction. The torque is measured (S113).

Thereafter, the torque correcting unit 9 corrects the static friction torque measured in step S113 (S115).

Those of ordinary skill in the art to which the present invention pertains will appreciate that the present invention may be implemented in other specific forms without changing its technical spirit or essential features. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the following claims rather than the above detailed description, and it should be interpreted that all changes or modified forms derived from the meaning and scope of the claims and equivalent concepts thereof are included in the scope of the present invention. do.

10: static friction torque measuring device
1: Base plate
2: Body structure
3: Bar structure
4: first specimen
5: second specimen
6: Talk plate
7: Upper plate
8: adapter
9: Torque correction unit
P01: Ceramic band heater
P02: Bearing
P03: Hydraulic cylinder
P04: Torque wrench

Claims (6)

A method for measuring static friction torque acting on a first specimen simulating a compressor and a second specimen simulating a turbine wheel,
A load acting step in which a compressive load is applied to the first specimen and the second specimen;
A heating step of heating the first specimen and the second specimen;
A temperature measurement step of measuring temperatures of the first specimen and the second specimen;
A torque action step of applying torque to the first specimen and the second specimen;
A torque measurement step of measuring torque up to the point at which the first specimen and the second specimen slip; And
A static torque correction step of correcting the torque measured in the torque measurement step by using a distance from an external force acting point to the first specimen and the second specimen and a distance from the external force acting point to the torque measuring point. How to measure friction torque. According to claim 1,
The heating step is a static friction torque measuring method of heating the first specimen and the second specimen when the compressive load acting in the loading operation step reaches a reference load. According to claim 1,
The heating step is a static friction torque measuring method of heating the first specimen and the second specimen to a reference temperature. According to claim 3,
The torque acting step is a static friction torque measuring method of applying torque to the first specimen and the second specimen when the temperatures of the first specimen and the second specimen reach the reference temperature. According to claim 1,
The torque measurement step is a static friction torque measuring method for measuring torque from a point at which torque is applied to the first specimen and the second specimen to a point at which the first specimen and the second specimen slip. According to claim 1,
In the torque correction step, the torque measured in the torque measurement step is multiplied by a distance from the external force acting point to the first specimen and the second specimen, and divided and corrected by dividing a distance from the external force acting point to the torque measuring point. Static friction torque measurement method.

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