RU2480632C1 - Connection of impeller with pinion shaft on front teeth (versions) - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: according to the first version connection of impeller with pinion shaft on front teeth includes front teeth of triangular profile that are engaged and performed on front ends of connected parts constricted by axial force. Front teeth have asymmetric triangular profile. The surface of working face of each tooth is parallel to pinion shaft rotation axis and perpendicular to vector M_r/R_av, where M_r - the moment of rotation, R_av - average radius.

EFFECT: increase of reliability of impeller connection to pinion shaft on front teeth.

6 cl, 8 dwg

Description

The group of inventions relates to centrifugal compressors, in particular to the design of the connection of the impeller with the gear shaft of the multiplier centrifugal compressor (MCC).

Known methods for the self-centering connection of two parts on the end slots, representing the teeth of a symmetrical triangular profile, cut at the ends of the parts to be joined and pulled together by axial force using a stud and nut (I and II).

In the source (I) it is shown that when the torque M _cr is transmitted to the connection, an axial force P _OS arises, which is aimed at opening the joint:

Where

α is the angle between the faces of the teeth;

R _cp is the average radius.

In order to avoid the disclosure of the joint, the tightening force of the stud P _z should be equal to:

P _zat = n · P _OS

Where

n = 1.5 ... 2.0 (safety factor);

P _os - axial force.

In the source (II), an expression is given for determining the total tightening torque of the studs necessary to compensate for the loads arising from the transmission of torque M _cr from the pinion shaft to the impeller.

One of the components of this force is the axial force where

Where

R _cp is the average radius;

α is half the angle of the symmetrical profile of the front tooth;

7 ° is the angle of friction.

These forces additionally load the pin, thereby reducing the reliability of the connection.

The technical result of the group of inventions is to increase the reliability of the connection of the impeller with the pinion shaft on the end teeth.

, гдеThe technical result is achieved due to the fact that in the connection of the impeller with the pinion shaft on the end teeth according to the first embodiment, which includes the end teeth of the triangular profile, which are meshed made on the ends of the parts to be joined together by axial force, according to the change, the end teeth have an asymmetric triangular a profile, while the surface of the working face of each tooth is parallel to the axis of rotation of the pinion shaft and perpendicular to the vector

where

M _cr - torque;

R _cp is the average radius.

, осевая сила

не возникает.Due to the fact that the surface of the working face of each tooth is perpendicular to the vector

axial force

does not occur.

Furthermore, the surface inoperative faces of the teeth of the two parts are in contact on the periphery at a distance R from the shaft-gear rotation axis and between the faces of the teeth at a distance R ₀ from said axis a gap a, the angle γ between the generators of the teeth of the parts in axial section, selected from the condition:

Where

- расчетный угол между образующими зубьев соединяемых деталей в осевом сечении;

- the calculated angle between the generatrix of the teeth of the connected parts in axial section;

γ is the angle between the generatrix of the teeth of the joined parts in axial section;

n is the number of teeth;

a is the size of the gap on the non-working edges of the teeth at a distance R ₀ ;

α is the angle between the faces of the teeth;

R is the radius of the outer lateral surfaces of the teeth;

R ₀ is the radius of the inner side surfaces of the teeth.

Furthermore, the magnitude of the gap and is selected from the condition providing plastic deformation surfaces inoperative faces, starting from a distance R up to the disappearance of the gap and the distance R ₀ by the action of the axial force.

The means for creating axial force is preferably a tie rod, the diameter of the rod of which is chosen to be at least 0.5 R provided that it generates a voltage of not more than 0.6 σ _t when σ _{t of the} material of the pin is not less than 900 MPa.

The technical result is achieved due to the fact that in the connection of the impeller with the pinion shaft of the multiplier centrifugal compressor according to the second embodiment, including the gears made on the ends of the joined parts pulled together by axial force, the end teeth of the triangular profile, according to the change, the end teeth have an asymmetric triangular profile, while the surface of the working face of each tooth is located at an angle β to the axis of rotation of the pinion shaft, selected from the condition of providing a given axial force:

Where

M _cr - torque;

R _cp is the average radius;

β - the working and non-working faces of each tooth lie on one side of the plane passing through the edge of this angle between the faces of the tooth and parallel to the axis of rotation.

In addition, the angle γ between the generatrix of the teeth of the connected parts in the axial section is selected from the condition:

Where

δ is the angle between the projections of the depression line and the vertex line of the working face of the tooth onto a plane perpendicular to the axis of rotation (in two places);

α is the angle between the faces of the teeth.

The essence of the group of inventions is illustrated by drawings, where

- figure 1 (a) schematically shows the proposed (according to option I) the connection of the impeller with the pinion shaft on the end teeth;

- figure 1 (b) schematically shows a fragment of the end teeth of a triangular profile of the proposed (in option I) connection of the impeller with the pinion shaft (section CC in figure 1 (a));

- figure 1 (c) schematically shows a fragment of non-working edges of the teeth of the proposed (according to option I) connection of the impeller with the pinion shaft, between which a clearance a is made (section C ₁ -C ₁ in figure 1 (a));

- figure 2 (a) schematically shows the proposed (according to option II) connection of the impeller with the pinion shaft on the end teeth;

- figure 2 (b) schematically shows a fragment of the end teeth of a triangular profile of the proposed (option II) connection of the impeller with the pinion shaft (section EE in figure 2 (a));

- figure 3 (a) schematically shows the letter designation of the angle γ;

;- figure 3 (b) schematically shows the lettering of the angles δ and

;

- figure 3 (c) schematically shows the letter designations of the angles α and β.

The connection (Fig. 1 (a)) of the impeller with the pinion shaft (according to option I) of the multiplier centrifugal compressor consists of the impeller 1, pinion shaft 2, pin 3 and nut 4.

The connection of the impeller with the pinion shaft of the multiplier centrifugal compressor contains end teeth 5, which are made at the ends of the connected parts 1 and 2. The end teeth 5 of the triangular profile are engaged, axially tightened and have an asymmetric profile.

, гдеThe surface 6 (Fig. 1 (b)) of the working face of each tooth 5 is parallel to the axis of rotation 7 of the pinion shaft 2 (Fig. 1 (a)) and is perpendicular to the vector

where

M _cr - torque;

R _cp is the average radius.

When transmitting torque from the pinion shaft 2 to the impeller 1, the following loads occur.

1. From the gas-dynamic axial force acting on the impeller;

2. From bending moment caused by residual imbalance of the impeller;

3. From radial dynamic elastic deformation of the impeller hub.

The axial force required to compensate for these loads is selected from the condition:

Where

K = 1,5 ... 2 - safety factor;

F ₀ - axial gas-dynamic force;

S and W are the area and moment of resistance of the middle section of the compound;

µ, δ - residual moment and static imbalance of the impeller;

C is the distance from the center of inertia of the impeller to the middle section of the connection;

S _article , L _article - the area and free length of the coupling rod;

ω is the angular velocity;

ΔR is the radial dynamic elastic deformation of the impeller hub on R;

E is the modulus of elasticity.

For a complete fit of the surfaces of the mating teeth 5, it is necessary that the generators of the teeth converge in the center of the joint at point O located on the axis of rotation 7 of the pinion shaft 2 (Fig. 1 (a)).

For a given number of teeth n on one of the connected parts of the angle α, the angle γ _calculation , with an asymmetric triangular profile of the tooth, is determined from the condition:

Where

α is the angle between the faces of the teeth;

γ _calculation - the angle between the generatrix of the teeth of the joined parts in axial section.

The surface 8 (Fig. 1 (b)) of the non-working edges of the teeth 5 of the two parts are contacted at the periphery at a distance R from the axis of rotation 7 of the pinion shaft 2. And between the faces 8 of the teeth 5 at a distance R ₀ from the axis 7, a gap a is made (Fig. 1 (c)). The angle γ is the angle between the generatrix of the teeth 5 of the connected parts. The axial force is created by the coupling pin 3 (Fig. 1 (a)).

The connection (Fig. 2 (a)) of the impeller with the pinion shaft (according to variant II) of the multiplier centrifugal compressor consists of the impeller 9, the pinion shaft 10, the stud 11 and the nut 12.

The connection of the impeller with the pinion shaft of the multiplier centrifugal compressor contains end teeth 13 (Fig. 2 (b)), which are made at the ends of the connected parts 9 and 10 (Fig. 2 (a)). The end teeth 13 of the triangular profile are engaged, tightened by axial force and have an asymmetric profile.

The surface 14 (figure 2 (b)) of the working face of each tooth 13 is located at an angle β to the axis of rotation 15 of the pinion shaft 10, selected from the condition of providing a given axial force:

Where

M _cr - torque;

R _cp is the average radius;

β - the working and non-working faces of each tooth lie on one side of the plane passing through the edge of this angle between the faces of the tooth and parallel to the axis of rotation.

на составляющие возникает осевая сила

которая направлена на стягивание стыка, и радиальная сила

Due to the fact that the surface 14 of the working face of each tooth 13, through which the torque M _cr is transmitted, is located at an angle β to the axis of rotation 15 of the pinion shaft 10 (Fig. 2 (a)), when the force is decomposed

axial force arises on components

which aims to tighten the joint, and radial force

Thus, the total tightening force of the stud 11, necessary to compensate for the loads arising from the transmission of torque from the pinion shaft 10 to the impeller 9 with an asymmetric tooth profile 13 with angles α and β, decreases, thereby increasing the reliability of the connection.

To fit the working surfaces of the teeth 13, all of their generators must converge at point O (Fig.2 (a)).

(фиг.3(б)).To determine the angle γ (Fig. 2 (a), 3 (a)) for a given number of teeth n and angles α and β (Fig. 2 (b), 3 (c)) we denote the angle CO ₁ B = δ, the angle

(Fig. 3 (b)).

(фиг.3(б)) и (α+β) (фиг.3(в)).To fulfill the condition of the abutment of the working surfaces of the teeth 13 and the convergence of all generators at the point O, it is necessary that the angle γ (Fig. 3 (a)) for a pair of angles δ (Fig. 3 (b)) and β (Fig. 3 (c)) equal to the angle γ (Fig.3 (a)) for a pair of angles

(Fig. 3 (b)) and (α + β) (Fig. 3 (c)).

и (α+β).Define the angle γ for a pair of angles

and (α + β).

From the drawing (figure 3 (a)) it is seen that HS = 2Rsin γ = ГD + DC;

(фиг.3(в));

(Fig. 3 (c));

(фиг.3(б));

(Fig. 3 (b));

Define DC.

(фиг.3(б));

DC = A ₁ C · sinγ (Fig. 3 (a)); A ₁ C = CO ₁ —O ₁ A ₁ (FIG. 3 (a)); CO ₁ = R;

(Fig. 3 (b));

After the conversion we get:

Similarly, for a pair of angles δ and β we get:

значит

mean

и далее sinγ и угол γ.For given values of α, β, and n, we can determine

and further sinγ and angle γ.

Information sources

(I) P.I.Orlov "Fundamentals of Design", Volume 2, publication "Engineering", M., 1977, p.267.

(II) VB Schnepp "Design and calculation of centrifugal compressor machines", publication "Engineering", M., 1995, p. 94.

Claims (6)

1. The connection of the impeller with the pinion shaft of a multiplier centrifugal compressor, including meshing made on the ends of the connected parts, pulled together by axial force, the end teeth of a triangular profile, characterized in that the end teeth have an asymmetric triangular profile, while the surface of the working face of each tooth parallel to the axis of rotation of the pinion shaft and perpendicular to the vector

,
where M _cr - torque;
R _cp is the average radius. 2. The compound according to claim 1, characterized in that the surfaces of the non-working faces of the teeth of the two parts are in contact at the periphery at a distance R from the axis of rotation of the pinion shaft, and there is a gap a between these faces of the teeth at a distance of R ₀ from this axis, and the angle γ between the generatrix of the teeth of the joined parts in axial section is selected from the condition

Where

γ _calculation - the estimated angle between the generatrix of the teeth of the connected parts in axial section;
γ is the angle between the generatrix of the teeth of the joined parts in axial section;
n is the number of teeth;
and - the gap on the non-working edges of the teeth at a distance R ₀ ;
α is the angle between the faces of the teeth;
R is the radius of the outer lateral surfaces of the teeth;
R ₀ is the radius of the inner side surfaces of the teeth. 3. The compound according to claim 2, characterized in that the gap value a is selected from the condition of ensuring plastic deformation of the surfaces of non-working faces, starting from a distance R until the gap a disappears at a distance R ₀ under the action of axial force. 4. A compound according to claim 2, characterized in that the means for creating the axial force is a coupling pin, the diameter d of the rod is at least provided 0,5R selected to create stress therein of not more than 0.6 when σ _t σ _t studs material not less than 900 MPa. 5. The connection of the impeller with the gear shaft of the centrifugal compressor, including meshing made on the ends of the parts to be joined, pulled together by axial force, the end teeth of a triangular profile, characterized in that the end teeth have an asymmetric triangular profile, while the surface of the working face of each tooth located at an angle β to the axis of rotation of the pinion shaft, selected from the condition of providing a given axial force:

where M _cr - torque;
R _cp is the average radius;
β - the working and non-working faces of each tooth lie on one side of the plane passing through the edge of this angle between the faces of the tooth and parallel to the axis of rotation. 6. The connection according to claim 5, characterized in that the angle γ between the generatrix of the teeth of the connected parts in axial section is selected from the condition

,
where δ is the angle between the projections of the depression line and the vertex line of the working face of the tooth on a plane perpendicular to the axis of rotation (in two places);
α is the angle between the faces of the teeth.

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