CN103334798B - Multi-arc specially-shaped hole - Google Patents

Abstract

A multi-arc specially-shaped hole comprises a largest lengthwise outline a and a largest crosswise outline b, wherein the largest lengthwise outline a is smaller than or equal to the largest crosswise outline b. The geometric outline of the multi-arc specially-shaped hole is formed by eight arcs which are tangent smoothly. The eight arcs comprise a top portion main arc with radius R1, a bottom main arc with radius R2, two side main arcs with radius R3 which are symmetrical about the Y axis, two upper transition arcs with radius R4 which are symmetrical about the Y-axis and two lower transition arcs with radius R5 which are symmetrical about Y-axis. The multi-arc specially-shaped hole effectively solves the problems of stress concentration of hole structures such as bolt holes and pressure equalizing holes in an existing engine turbine disc and an existing compressor disc, and the service life of the structure can be prolonged.

Description

Many circular-arc abnormal-shapes hole

Technical field:

The present invention relates to a kind of hole structure such as bolt hole, pin hole, vent be applied in aeroengine rotor structure, particularly relate to a kind of many circular-arc abnormal-shapes hole.

Background technique:

Bolt hole, pin hole, vent are the common structures on aeroengine wheel disc, and they will reduce the bulk strength of structure to the weakening of wheel disc bearing capacity.Simultaneously because the cross section in existing hole is circular, more serious stress can be produced when bearing the multiaxial loading that each stress value does not wait and concentrate, and then cause radial cracking fault to occur, very remarkable on the impact in wheel disc life-span.

For the problem of stress concentration of balancing orifice, bolt hole on wheel disc during engine design manufactures, often take the technological measures such as limit, hole chamfering, polishing to carry out harm reduction, sometimes also directly can cancel balancing orifice.But chamfering, glossing are very limited to the effect alleviating hole-edge stress concentration, cancel balancing orifice then unfavorable to cavity air pressure before and after balance wheel disc.Reducing stress level by increase physical dimension obviously can cause weight to increase.Therefore, a kind of brand-new method of needs be addressed this problem.

A kind of method of effective reduction hole-edge stress concentration adopts non-circular hole structure.Not rounded profiled holes (non-circularhole) refers to that profile is the hole of non-circular closed curve.Not rounded profiled holes is often applied to hydro-structure, mine tunnel structure, and shell open-celled structure and engine gudgeon pin hole structure etc., some parts of external aeroengine also use profiled holes structure.

Before the CFM56-3 h type engine h high-pressure turbine dish of GE company of the U.S., mounting edge used similar many circular arcs special type hole structure, as shown in Figure 1.Wherein, in accompanying drawing 1, label 1 is basic circle profile, and label 2 is the orthodrome in special type hole, and label 3 is the small arc-shaped in special type hole.

The profile in this special type hole (profiled holes) is that some circular sliding slopes form.The stress that this improvement effectively reduces near bolt hole is concentrated, and improves the fatigue life of the turbine disk.The use practice for many years of CFM56-3 h type engine h is verified, this improvement be reliable and effective [Chen Guang .CFM56 Engine Series structural design and development feature [M]. publishing house of BJ University of Aeronautics & Astronautics, 2006].But this profiled holes is only containing two design variables, and maximum horizontal stroke, vertical profile length are equal, and the space of Optimal improvements is little.

Summary of the invention:

The invention provides a kind of many circular-arc abnormal-shapes hole, it effectively solves the stress concentration phenomenon of the hole structure such as bolt hole, balancing orifice on the available engine turbine disk, compressor disc, improves structure working life.

The present invention adopts following technological scheme: a kind of many circular-arc abnormal-shapes hole, it comprises maximum longitudinal profile is a, maximum transversal profile is b, described maximum longitudinal profile is that a is less than or equal to maximum transversal profile b, described many circular-arc abnormal-shapes pore geometry profile is made up of eight sections of smooth tangent circular arcs, and described eight sections of circular arcs are a radius is R ₁the main circular arc in top, a radius is R ₂the main circular arc in bottom, two radiuses about Y-axis symmetry are R ₃the main circular arc of side, two radiuses about Y-axis symmetry are R ₄upper transition arc and two radiuses about Y-axis symmetry be R ₅lower transition arc, the relative Y-axis of the profile in described many circular-arc abnormal-shapes hole is symmetrical, and described many circular-arc abnormal-shapes hole is divided into I nibs, II nibs, type III hole and IV nibs, is R for minimum machining diameter during milling cutter perforate to described many circular-arc abnormal-shapes hole perforate _min;

In described I nibs: when a=b and the profile twin shaft in hole are symmetrical:

Main circular arc: R ₁>a, R ₃>a;

Transition arc: a>R ₄>R _min;

In described II nibs: a=b and the profile mono-symmetry in hole time:

Main circular arc: R ₁>a, R ₃>a, R ₂>a;

Transition arc: a>R ₄>R _min, and a>R ₅>R _min;

In described type III hole: when b>a and the profile twin shaft in hole are symmetrical:

Main circular arc: $R_1>\frac{a^2+b^2}{2a},R_3>\frac{b^2+m^2-{R_1}^2}{2(b-R_1)};$

Transition arc: $\frac{b^2+m^2-{R_1}^2}{2(b-R_1)}>R_4>R_{\min };$

(wherein m=R ₁-a);

In described IV nibs: b>a and the profile mono-symmetry in hole time:

Main circular arc: $R_1>\frac{a^2+b^2}{2a},R_2>\frac{a^2+b^2}{2a},R_3>\frac{b^2+m^2-{R_1}^2}{2(b-R_1)};$

Transition arc: $R_{\min }<R_4<\frac{b^2+m^2-{R_1}^2}{2(b-R_1)};$

$R_{\min }<R_5<\frac{b^2+m^{\&prime;2}-{R_2}^2}{2(b-R_2)}$

(wherein m '=R ₂-a);

Described four kinds of profiled holes transition arc central coordinate of circle unification is:

$x_4=\frac{-\mathrm{en}-2{\mathrm{nm}}^2-\sqrt{-e^2{m}^2+4{\mathrm{em}}^2{n}^2+4j^2{m}^2{n}^2-4m^2{n}^4+4j^2{m}^4}}{2(m^2+n^2)}$

$y_4=\frac{\mathrm{em}-2{\mathrm{mn}}^2+\sqrt{-e^2{n}^2-4{\mathrm{em}}^2{n}^2+4i^2{m}^2{n}^2-4m^4{n}^2+4i^2{n}^4}}{2(m^2+n^2)}$

Wherein: m=R ₁-a, n=b-R ₃, i=R ₁-R ₄, j=R ₃-R ₄, e=i ²-j ²+ n ²-m ²;

$x_5=\frac{-e^{\&prime;}{n}^{\&prime;}-2n^{\&prime;}{m}^{\&prime;2}-\sqrt{-e^{\&prime;2}{m}^{\&prime;2}+4{e^{\&prime;}m}^{\&prime;2}{n}^{\&prime;2}+4j^{\&prime;2}{m}^{\&prime;2}{n}^{\&prime;2}-4m^{\&prime;2}{n}^{\&prime;4}+4j^{\&prime;2}{m}^{\&prime;4}}}{2(m^{\&prime;2}+n^{\&prime;2})}$

$y_5=\frac{e^{\&prime;}{m}^{\&prime;}-2m^{\&prime;}{n}^{\&prime;2}+\sqrt{-e^{\&prime;2}{n}^{\&prime;2}-4{e^{\&prime;}m}^{\&prime;2}{n}^{\&prime;2}+4i^{\&prime;2}{m}^{\&prime;2}{n}^{\&prime;2}-4m^{\&prime;4}{n}^{\&prime;2}+4i^{\&prime;2}{n}^{\&prime;4}}}{2(m^{\&prime;2}+n^{\&prime;2})}$

Wherein: m'=R ₂-a, n'=b-R ₃, i'=R ₂-R ₅, j'=R ₃-R ₅, e'=i' ²-j' ²+ n' ²-m' ².

The present invention has following beneficial effect: eight sections of circular-arc abnormal-shape holes are a kind of parametrization pass, its profile can change according to the change of profiled holes design parameter, thus adapt to the stressing conditions of tapping, the stress reducing limit, hole is concentrated, circular port is substituted with eight sections of circular-arc abnormal-shape holes, and after being optimized profiled holes design parameter on the basis of finite element stress analysis, the stress that significantly can reduce limit, hole is concentrated, and improves structure working life.

Accompanying drawing illustrates:

Fig. 1 is mounting edge special type hole before CFM56-3 h type engine h high-pressure turbine dish of the prior art.

Fig. 2 is the geometric profile in the present invention's many circular-arc abnormal-shapes hole.

Fig. 3 is the classification in the present invention's many circular-arc abnormal-shapes hole.

Fig. 4 is turbine disk simulation model (1/48 fan-shaped section).

Fig. 5 is the first principal stress cloud atlas of circular hole (left side) and optimum profiled holes (right side).

Fig. 6 is mounting edge model before high-pressure turbine.

Fig. 7 for replace circular hole and through optimization after many circular-arc abnormal-shapes hole first principal stress cloud atlas.

Wherein:

1-basic circle profile; The orthodrome in 2-special type hole; The small arc-shaped in 3-special type hole; The maximum longitudinal profile a of 4-; 5-maximum transversal profile b; 6-radius is R ₁the main circular arc in top; 7-radius is R ₂the main circular arc in bottom; 8-radius is R ₃the main circular arc of side; 9-radius is R ₄upper transition arc; 10-radius is R ₅lower transition arc; 11-I nibs (a=b, twin shaft is symmetrical); 12-II nibs (a=b, mono-symmetry); 13-III nibs (a ≠ b, twin shaft is symmetrical); 14-IV nibs (a ≠ b, mono-symmetry); 15-wheel rim surface; Mounting edge after 16-; Mounting edge before 17-; Mounting edge upper-end surface before 18-; Mounting edge bolt hole before 19-; The maximum stress point of 20-circular hole; 21-adopts the maximum stress point of optimal solution profiled holes; 22-bolt hole; Limit, 23-hole maximum stress point.

Embodiment:

Please refer to shown in Fig. 2, the diameter improving front circular bolt hole is defined as a.Maximum longitudinal profile of profiled holes profile is a, and maximum transversal profile is b, and requires a≤b.Many circular-arc abnormal-shapes pore geometry profile is made up of eight sections of smooth tangent circular arcs.The profile in regulation hole is symmetrical about Y-axis, and eight sections of circular arcs are respectively a main circular arc R in top ₁(R ₁for radius), a main circular arc R in bottom ₂(R ₂for radius), two main circular arc R of the side about Y-axis symmetry ₃(R ₃for radius), two about Y-axis to being much of transition arc R ₄(R ₄for radius) and two lower transition arc R about Y-axis symmetry ₅(R ₅for radius).

In Fig. 2, dotted outline is the basic circle profile in former design, and the profile in eight sections of circular-arc abnormal-shape holes is by R ₁-R ₅totally 5 radius size and maximum longitudinal profile a, maximum transversal profile b, totally seven design variables determine.As b>a, under the prerequisite keeping radial aperture positioning tolerance constant, the tolerance to circumferential position of opening error can be increased.

Please refer to shown in Fig. 3, eight sections of circular-arc abnormal-shape holes are divided into I-IV type Four types according to the relation of the symmetry characteristic of himself and maximum longitudinal profile a, maximum transversal profile b.

The relative Y-axis of profile due to eight sections of circular-arc abnormal-shape holes is symmetrical, existing for the hole of circular-arc abnormal-shape more than 1/4th of second and third quadrant, provides the uniform mathematical model of four kinds of profiled holes.Comprise span and the central coordinate of circle representation thereof of the radius of arc of four kinds of profiled holes, and the representation of transition arc and main circular arc point of contact coordinate.The circular arc span of each nibs is:

11. as a=b and the profile twin shaft in hole is symmetrical time (I nibs):

Main circular arc: R ₁>a, R ₃>a

Transition arc: a>R ₄>R _min(R _minminimum machining diameter for during milling cutter perforate).

12. as a=b and the profile mono-symmetry in hole time (II nibs):

Main circular arc: R ₁>a, R ₃>a, R ₂>a;

Transition arc: a>R ₄>R _min, and a>R ₅>R _min.

13. as b>a and the profile twin shaft in hole is symmetrical time (type III hole):

Main circular arc: $R_1>\frac{a^2+b^2}{2a},R_3>\frac{b^2+m^2-{R_1}^2}{2(b-R_1)};$

Transition arc: $\frac{b^2+m^2-{R_1}^2}{2(b-R_1)}>R_4>R_{\min }.$

(wherein m=R ₁-a).

14. as b>a and the profile mono-symmetry in hole time (IV nibs):

Main circular arc: $R_1>\frac{a^2+b^2}{2a},R_2>\frac{a^2+b^2}{2a},R_3>\frac{b^2+m^2-{R_1}^2}{2(b-R_1)};$

Transition arc: $R_{\min }<R_4<\frac{b^2+m^2-{R_1}^2}{2(b-R_1)};$

$R_{\min }<R_5<\frac{b^2+m^{\&prime;2}-{R_2}^2}{2(b-R_2)}$

(wherein m '=R ₂-a).

And four kinds of profiled holes transition arc central coordinate of circle can unify be:

$x_4=\frac{-\mathrm{en}-2{\mathrm{nm}}^2-\sqrt{-e^2{m}^2+4{\mathrm{em}}^2{n}^2+4j^2{m}^2{n}^2-4m^2{n}^4+4j^2{m}^4}}{2(m^2+n^2)}$

$y_4=\frac{\mathrm{em}-2{\mathrm{mn}}^2+\sqrt{-e^2{n}^2-4{\mathrm{em}}^2{n}^2+4i^2{m}^2{n}^2-4m^4{n}^2+4i^2{n}^4}}{2(m^2+n^2)}$

Wherein: m=R ₁-a, n=b-R ₃, i=R ₁-R ₄, j=R ₃-R ₄, e=i ²-j ²+ n ²-m ².

$x_5=\frac{-e^{\&prime;}{n}^{\&prime;}-2n^{\&prime;}{m}^{\&prime;2}-\sqrt{-e^{\&prime;2}{m}^{\&prime;2}+4{e^{\&prime;}m}^{\&prime;2}{n}^{\&prime;2}+4j^{\&prime;2}{m}^{\&prime;2}{n}^{\&prime;2}-4m^{\&prime;2}{n}^{\&prime;4}+4j^{\&prime;2}{m}^{\&prime;4}}}{2(m^{\&prime;2}+n^{\&prime;2})}$

$y_5=\frac{e^{\&prime;}{m}^{\&prime;}-2m^{\&prime;}{n}^{\&prime;2}+\sqrt{-e^{\&prime;2}{n}^{\&prime;2}-4{e^{\&prime;}m}^{\&prime;2}{n}^{\&prime;2}+4i^{\&prime;2}{m}^{\&prime;2}{n}^{\&prime;2}-4m^{\&prime;4}{n}^{\&prime;2}+4i^{\&prime;2}{n}^{\&prime;4}}}{2(m^{\&prime;2}+n^{\&prime;2})}$

Wherein: m'=R ₂-a, n'=b-R ₃, i'=R ₂-R ₅, j'=R ₃-R ₅, e'=i' ²-j' ²+ n' ²-m' ²

Please refer to shown in Fig. 4, it is turbine disk simulation model (1/48 fan-shaped section), these eight sections of circular-arc abnormal-shape holes are used to improve the circular bolt holes on mounting edge and optimize. this turbine disk is symmetric form hollow not uniform thickness dish, before and after respectively have a mounting edge. front mounting edge 17 circumferentially evenly has 48 bolts hole, use lag bolt connect the turbine disk and before to obturage labyrinth, turbine drum barrel axle.

Please refer to shown in Fig. 4 and Fig. 5, in the diagram, because in the former design of motor mounting edge, circular bolt hole exists stress concentration phenomenon, therefore use many circular-arc abnormal-shapes hole (IV type) to replace circular bolt hole in former design.Circular bolt hole radius r in the design of its Central Plains is 5mm, and maximum longitudinal profile a of profiled holes equals circle hole radius r, and maximum transversal profile b equals 5.25mm (above size follows ANSI bolt hole dimensional standard series).With R ₁-R ₅5 radius size are design variable, and the maximum first principal stress in limit, hole is optimization aim, is optimized design based on finite element stress analysis, obtain the optimum pass shown in Fig. 5 (right side).This hole can adopt drilling, milling, the combinational processing method processing that grinding combines; Or adopt spark erosion machining perforate, then use abradant jet technique to remove heat affected layer.

Replace circle bolt hole with many circular-arc abnormal-shapes hole, carry out stress analysis with finite element analysis software, and profiled holes pass parameters is optimized.Optimum results shows: the many circular-arc abnormal-shapes hole adopting optimal solution, dangerous spot zone leveling stress level declines to a great extent.The region of high stress is mainly positioned on top, the main circular arc in bottom.The maximum first principal stress in bolt hole limit have dropped more than 14% compared with using the result of calculation of traditional round hole structure.The distribution of around-the-hole stress is more even.After optimization, structural volume reduces to some extent, and the utilization ratio of material is improved; The contour optimization result in hole shows, the top margin in hole and side are tending towards smooth, is concentrated by the stress contributing to relief holes limit high stress areas, reduces its first principal stress and equivalent stress.The first principal stress optimizing many circular-arc abnormal-shapes hole (optimized parameter profiled holes) and the former design circular hole drawn contrasts cloud atlas as shown in Figure 5.

Please refer to shown in Fig. 6 and Fig. 7, before the engine high pressure turbine disk there is stress concentration phenomenon in the bolt hole 22 of mounting edge, uses many circular-arc abnormal-shapes hole (I nibs) to replace circular bolt hole in former design.Circular bolt hole radius r in the design of its Central Plains is 5mm, and maximum longitudinal profile a of profiled holes, maximum transversal profile b are equal to circle hole radius r (following ANSI bolt hole dimensional standard series).With R ₁, R ₃, R ₄3 radius size are design variable, and the maximum first principal stress in limit, hole is optimization aim, is optimized design based on finite element stress analysis, obtain the optimum pass shown in Fig. 7.This hole can adopt drilling equally, milling, the combinational processing method processing that grinding combines; Or adopt spark erosion machining perforate, then use abradant jet technique to remove heat affected layer.

The above is only the preferred embodiment of the present invention, it should be pointed out that for those skilled in the art, can also make some improvement under the premise without departing from the principles of the invention, and these improvement also should be considered as protection scope of the present invention.

Claims (1)

1. circular-arc abnormal-shape hole more than a kind, it comprises maximum longitudinal profile is a, maximum transversal profile is b, described maximum longitudinal profile is that a is less than or equal to maximum transversal profile b, it is characterized in that: described many circular-arc abnormal-shapes pore geometry profile is made up of eight sections of smooth tangent circular arcs, described eight sections of circular arcs are a radius is R ₁the main circular arc in top, a radius is R ₂the main circular arc in bottom, two radiuses about Y-axis symmetry are R ₃the main circular arc of side, two radiuses about Y-axis symmetry are R ₄upper transition arc and two radiuses about Y-axis symmetry be R ₅lower transition arc, the relative Y-axis of the profile in described many circular-arc abnormal-shapes hole is symmetrical, and described many circular-arc abnormal-shapes hole is divided into I nibs, II nibs, type III hole and IV nibs, is R for minimum machining diameter during milling cutter perforate to described many circular-arc abnormal-shapes hole perforate _min;

In described I nibs: when a=b and the profile twin shaft in hole are symmetrical:

Main circular arc: R ₁>a, R ₃>a;

Transition arc: a>R ₄>R _min;

In described II nibs: a=b and the profile mono-symmetry in hole time:

Main circular arc: R ₁>a, R ₃>a, R ₂>a;

Transition arc: a>R ₄>R _min, and a>R ₅>R _min;

In described type III hole: when b>a and the profile twin shaft in hole are symmetrical:

Main circular arc: $R_1>\frac{a^2+b^2}{2a},$ $R_3>\frac{b^2+m^2{{-R}_1}^2}{2(b-R_1)};$

Transition arc: $\frac{b^2+m^2-{R_1}^2}{2(b-R_1)}>R_4>R_{\min };$

(wherein m=R ₁-a);

In described IV nibs: b>a and the profile mono-symmetry in hole time:

Main circular arc: $R_1>\frac{a^2+b^2}{2a},$ $R_2>\frac{a^2+b^2}{2a},$ $R_3>\frac{b^2+m^2{-R_1}^2}{2(b-R_1)};$

Transition arc: $R_{\min }<R_4<\frac{b^2+m^2-{R_1}^2}{2(b-R_1)};$

$R_{\min }<R_5<\frac{b^2+m^{\&prime;2}-{R_2}^2}{2(b-R_2)}$

(wherein m '=R ₂-a);

Described four kinds of profiled holes transition arc central coordinate of circle unification is:

$x_4=\frac{-\mathrm{en}-{2\mathrm{nm}}^2-\sqrt{-e^2{m}^2+{4\mathrm{em}}^2{n}^2+4j^2{m}^2{n}^2-4m^2{n}^4+4j^2{m}^4}}{2(m^2+n^2)}$

$y_4=\frac{\mathrm{em}-{2\mathrm{mn}}^2+\sqrt{-e^2{n}^2+{4\mathrm{em}}^2{n}^2+4i^2{m}^2{n}^2-4m^2{n}^4+4i^2{n}^4}}{2(m^2+n^2)}$

Wherein: m=R ₁-a, n=b-R ₃, i=R ₁-R ₄, j=R ₃-R ₄, e=i ²-j ²+ n ²-m ²;

$x_5=\frac{-e^{\&prime;}{n}^{\&prime;}-{2n}^{\&prime;}{m}^{\&prime;2}-\sqrt{-e^{\&prime;2}{m}^{\&prime;2}+4e^{\&prime;}{m}^{\&prime;2}{n}^{\&prime;2}+{4j}^{\&prime;2}{m}^{\&prime;2}{n}^{\&prime;2}-{4m}^{\&prime;2}{n}^{\&prime;4}+{4j}^{\&prime;2}{m}^{\&prime;4}}}{2(m^{\&prime;2}+n^{\&prime;2})}$

$y_5=-\frac{e^{\&prime;}{m}^{\&prime;}-{2m}^{\&prime;}{n}^{\&prime;2}+\sqrt{-e^{\&prime;2}{n}^{\&prime;2}-4e^{\&prime;}{m}^{\&prime;2}{n}^{\&prime;2}+{4i}^{\&prime;2}{m}^{\&prime;2}{n}^{\&prime;2}-{4m}^{\&prime;4}{n}^{\&prime;2}+{4i}^{\&prime;2}{n}^{\&prime;4}}}{2(m^{\&prime;2}+n^{\&prime;2})}$

Wherein: m'=R ₂-a, n'=b-R ₃, i'=R ₂-R ₅, j'=R ₃-R ₅, e'=i ^{' 2}-j ^{' 2}+ n ^{' 2}-m ^{' 2}.