CN201637539U - Instrument for measuring gravity center of propeller blade with controllable pitch - Google Patents

Abstract

The utility model discloses an instrument for measuring the gravity center of a propeller blade with controllable pitch, which comprises a base, three pressure sensors and a chuck, wherein the three pressure sensors are symmetrically mounted between the bottom surface of the chuck and the top surface of the base along the same circumferential direction so as to form three angles of 120 degrees, and the center of the circle formed by the three pressure sensors is positioned on the axis of the chuck, and one sensor can move up and down through a lifting system. By adopting the measuring instrument, the number of guide rails and position detecting equipment are reduced, and the accuracy in measurement is guaranteed; moreover, the measuring instrument can be suitable for propeller blades with various shapes.

Description

Adjustable pitch propeller blade gravity center measurement instrument

Technical field

The utility model relates to a kind of gravity center measurement instrument, particularly adjustable pitch propeller blade gravity center measurement instrument.

Background technology

Can accurately measure the method for controllable pitch propeller blade (hereinafter to be referred as blade) center of gravity at present and have only the supported at three point method, now have producer to utilize this method to produce the instrument of accurate measurement blade center of gravity, its theoretical model as shown in Figure 1.

Because propeller blade out-of-shape and blade face distortion are bigger, measure center of gravity and adopt the three-point support method.Components A must move up and down in the vertical plane, and part B and parts C must move with vertical direction in the horizontal direction at the surface level internal fixation in three supporting-points, and has certain adjustable extent.Record three position component and stressed by displacement transducer and pressure transducer 1-4, and utilizing equalising torque and geometric relationship to calculate the center of gravity of blade, the force measurement precision of each fulcrum and positional accuracy measurement have direct influence to the accuracy of final measurement.But this instrument exists following shortcoming:

(1) because sensor need slide, is equipped with corresponding location detecting apparatus and fixed equipment on guide rail 1-5, increased error, and increased the cost of instrument;

(2) need three points to be supported on the blade face when measuring, because blade form is irregular and the blade face distortion is bigger, blade might produce sideslip, the precision that influence is measured.

When (3) flange of blade was stuck on the chuck 1-7, root can produce big moment of flexure, and was higher to the rigidity requirement of lathe bed 1-6, and lathe bed length is bigger than the design radial R of blade, has increased the floor area of entire equipment.

(4) generally this technical device difficulty and manufacturing accuracy require height, and the structure more complicated also must be carried out meticulous maintaining, and the cost input is many.

Summary of the invention

The purpose of this utility model is to overcome the deficiency of prior art, provide a kind of can high-level efficiency, the adjustable pitch propeller blade gravity center measurement instrument of high-acruracy survey propeller blade production cost center of gravity and that reduce equipment.

Adjustable pitch propeller blade gravity center measurement instrument of the present utility model, it comprises base, three pressure transducers and chuck, described three pressure transducers are mutually 120 degree symmetries along same circumferencial direction and are installed between the end face of the bottom surface of chuck and base and the center of circle of three formed circles of sensor is positioned on the axis of described chuck, and a described sensor that links to each other with controller can move up and down by jacking system.

Advantage of the present utility model:

It is that center of circle radius is on the circle of r that (1) three sensor is fixed on O point (chuck reference surface center), and three sensors are mutually 120 symmetries and are installed under the chuck, has so just reduced guide rail and location detecting apparatus;

(2) blade vertically is placed on the chuck, and flange face is overlapped with the chuck reference field, guarantees measuring accuracy;

(3) chuck can make system's center of gravity reduction that chuck and blade are formed, and when No. 1 sensor promotes, prevents to produce and breaks away;

(4) this measuring method has been avoided contacting with the blade face, is not subjected to blade 8 shape constrainings, applicable to the blade of different shape, under the condition that the support strength of selecting for use allows, also is applicable to and measures relatively large propeller blade.

Adopt this device can high-level efficiency, the instrument of high-acruracy survey propeller blade center of gravity.

Description of drawings

Fig. 1 is the theoretical model of the instrument of existing accurate measurement blade center of gravity;

Fig. 2 is the structural representation of adjustable pitch propeller blade gravity center measurement instrument of the present utility model;

Fig. 3 adopts measuring instrument OXY plane surveying principle schematic shown in Figure 2;

Fig. 4 adopts measuring instrument OXZ plane surveying principle schematic shown in Figure 2;

Fig. 5 (1) and Fig. 5 (2) are the geometric relationship figure that asks Z.

Embodiment

Below in conjunction with the drawings and specific embodiments the utility model is described in detail.

Adjustable pitch propeller blade gravity center measurement instrument of the present utility model as shown in drawings, it comprises base 4, three pressure transducer 1-1,1-2,1-3 and chucks 5, described three pressure transducers are mutually 120 degree symmetries along same circumferencial direction and are installed between the end face of the bottom surface of chuck and base and the center of circle of three formed circles of sensor is positioned on the axis of described chuck, and a described sensor that links to each other with controller can move up and down by jacking system.The described controller that links to each other with a sensor in three sensors is used to show the reading of the sensor that is attached thereto.

Described jacking system can adopt multiple existing structure, as: described jacking system can comprise feed screw nut's structure, nut in described feed screw nut's structure links to each other with a sensor base and the described screw mandrel of setting vertically links to each other with the output shaft of motor, and described nut both sides link to each other by the guide rail slide block structure with described base.Perhaps described jacking system can comprise hydraulic cylinder, and the push rod of hydraulic cylinder vertically links to each other with the bottom of a described sensor.

Described chuck is buied in market, can adopt hand chuck or power chuck.

When blade is installed, flange 9 bottoms of blade clamp and closely contact with chuck fundamental plane 6 by the claw 7 of chuck, the integrated support that blade and chuck are formed is on the summit 1,2,3 of equilateral triangle, the center of the circle that forms and the vertical projection of the center O point of chuck reference field in surface level overlap, and guarantee that by the claw of chuck the position of each blade of measuring is identical.Three sensors are connected to these three points on the chuck, and sensor can record the pressure of 3 positions.Wherein ring can be regulated size adapting to the blade flanges of different sizes in the chuck, and the quality of chuck is m _Chuck, barycentric coordinates are (x under the OXYZ coordinate system shown in Fig. 3-4 _Chuck, y _Chuck, z _Chuck); No. 1 sensor 1-1 can regulate height, generally, for guaranteeing that chuck does not produce excessive moment of flexure, thereby influence measuring accuracy, and the chuck corner that is produced by No. 1 sensor adjustment height is no more than 5 and spends and be advisable; 2, No. 3 sensor 1-2,1-3 are highly fixing.

The measuring principle of the utility model device is as follows:

The first step guarantees three sensor height unanimities (being chuck and blade flange face maintenance level), the reading that pickup produces.

Set up as shown in Figure 3 two coordinate system OXYZ and OXYZ, the center of chuck reference field is the O point, and O, 1 line are X-axis, is parallel to 2,3 lines and crosses O point and set up Y-axis, and the O point is set up the Z axle straight up perpendicular to XOY plane excessively; With the center O point of 2,3 sensor lines, O, 1 line are X-axis, and 2,3 lines are Y-axis, cross the O point and set up the Z axle straight up perpendicular to XOY plane.

In the OXYZ coordinate system, to the equalising torque of X-axis, Y-axis, can get respectively

$\left\{\begin{array}{c}{X}^0=\frac{3R_{1}r}{2W}\\ Y^0=\frac{\sqrt{3}(R_2-R_3)}{2W}r\end{array}\right.---\left(1\right)$

General assembly (TW) is: W=R ₁+ R ₂+ R ₃(2)

Annotate: (X Y) is the barycentric coordinates of blade in the XOY coordinate system, and W is the weight of blade, R ₁, R ₂And R ₃For being respectively the reading of 1,2 and No. 3 sensor when measuring for the first time, r is the center of circle O o'clock distance to three center sensors.

Second step is with No. 1 sensor hoisting depth a

The anglec of rotation θ that is chuck is less than 5 degree, then The value that this moment, three sensors recorded is R ₁', R ₂' and R ₃'.

General assembly (TW) is: W '=R ₁'+R ₂'+R ₃'=W (3)

In like manner getting at this moment, barycentric coordinates are

$\left\{\begin{array}{c}{X}^{\&prime;}=\frac{3{R_1}^{\&prime;}r}{{2W}^{\&prime;}}\\ Y^{\&prime;}=\frac{\sqrt{3}({{\mathrm{<figure-callout\; id="2"\; label="R"\; filenames="HDA0000020079420000013.png,HDA0000020079420000023.png"\; state="\{\{state\}\}">R</figure-callout>}}_2}^{\&prime;}-{R_3}^{\&prime;})}{{2W}^{\&prime;}}r\end{array}\right.---\left(4\right)$

Y=Y ' wherein, as geometric relationship among Fig. 4 as can be known the length of AG be the Z value of being asked,

$Z^0=\frac{X^0}{\tan \mathrm{\&theta;}}-\frac{X^{\&prime;}}{\sin \mathrm{\&theta;}}=\frac{{9R}_1{\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA0000020079420000013.png,HDA0000020079420000023.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}{4\mathrm{Wa}}-\frac{{{3R}_1}^{\&prime;}r\sqrt{{4a}^2+{9\mathrm{<figure-callout\; id="2"\; label="r"\; filenames="HDA0000020079420000013.png,HDA0000020079420000023.png"\; state="\{\{state\}\}">r</figure-callout>}}^2}}{{4W}^{\&prime;}a}---\left(5\right)$

Then as can be known, X=X-r/2, Y=Y, Z=Z by the relation between two coordinate system OXYZ and the OXYZ.

The weight center of gravity of chuck is known, its W=W ', and then the barycentric coordinates of blade in the OXYZ coordinate system are:

Annotate: in the formula, R ₁', R ₂' and R ₃' be the reading that is respectively 1,2 and No. 3 sensor when measuring for the second time, (X, Y Z) are the barycentric coordinates of system in the OXYZ coordinate system that blade and chuck are formed, and (X, Y Z) are the barycentric coordinates of system in the OXYZ coordinate system that blade and chuck are formed, (X _Blade, Y _Blade, Z _Blade) be blade coordinate in the OXYZ coordinate system, W ' is that the weight of blade equates with W, a is the height of No. 1 sensor rising.

3, error analysis

Represent error with differential form, can get the error of blade in all directions:

Δ R ₁, Δ R ₂, Δ R ₃, Δ R ₁' be the error that sensor produces, if adopt the sensor of same model can think that its error amount equates Δ R _i=Δ R _i'=Δ R (i=1,2,3), then Δ W=3 Δ R.Δ r is the error that three sensor installation sites produce, and Δ a is the error of No. 1 sensor generation that raises, Δ m _ChuckThe error that produces during for measurement chuck weight, Δ x _Chuck, Δ y _Chuck, Δ z _ChuckBe respectively the error that produces when measuring the chuck center of gravity, g is an acceleration of gravity.

Adopt the output numerical value of this instrument read sensor can obtain the coordinate figure of adjustable pitch propeller blade center of gravity by aforementioned calculation.

This instrument utilizes the supported at three point ratio juris, and, each cross section all irregular singularity big, complex-shaped at weight of propeller blades by blocking the chuck of flange, allows sensor contact with chuck, the three-dimensional coordinate of indirect measurement blade.By to the analysis of the explanation of its principle and error as can be seen, this instrument still can guarantee the measuring accuracy of blade center of gravity, can reduce the cost of equipment simultaneously, increases work efficiency.

Claims (3)

1. adjustable pitch propeller blade gravity center measurement instrument, it comprises base, three pressure transducers and chuck, it is characterized in that: described three pressure transducers are mutually 120 degree symmetries along same circumferencial direction and are installed between the end face of the bottom surface of chuck and base and the center of circle of three formed circles of sensor is positioned on the axis of described chuck, and a described sensor that links to each other with controller can move up and down by jacking system.

2. adjustable pitch propeller blade gravity center measurement instrument according to claim 1, it is characterized in that: described jacking system comprises feed screw nut's structure, nut in described feed screw nut's structure links to each other with a sensor base and the described screw mandrel of setting vertically links to each other with the output shaft of motor, and described nut both sides link to each other by the guide rail slide block structure with described base.

3. adjustable pitch propeller blade gravity center measurement instrument according to claim 1, it is characterized in that: described jacking system comprises hydraulic cylinder, the push rod of hydraulic cylinder vertically links to each other with the bottom of a described sensor.

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