RU2013567C1 - Rotary machine - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: rotary machine has stator whose interior is defined by cylindrical surface with major radius, shaped surface including cylindrical surface of minor radius, and two intermediate portions therebetween. The intermediate portions accommodate inlet and outlet ports to allow the passage of working fluid through gate. The gate has a length equal to the length of working chamber of the stator and a width equal to the sum of major and minor radii of the cylindrical surfaces. The gate is located in recess of the rotor and extends through the axis of rotation of the rotor. The stator has the form of a sleeve with inner diameter equaling to twice the radius. The stator has a sickle-shaped insert with cylindrical outer surface of a radius equal to the major radius. EFFECT: enhanced efficiency in operation. 5 dwg, 1 tbl

Description

 The invention relates to the structure of engines and compressors and can be used in the food, energy, aviation industry, for example, for supplying dry air, as a pneumatic actuator, pneumatic tool, pneumatic compressor.

 Known rotary volume displacement machine, consisting of a stator, a rotor coaxial with it and a gate inserted into the groove of the rotor, and the inner surface of the stator is formed by a body of revolution of complex shape. The disadvantage of this design is the complexity of its manufacture, because obtaining the above-mentioned inner surface of the stator is associated with significant technological difficulties.

 Known rotary machine containing a stator, the inner surface of which is formed by a cylindrical surface with a large radius R and a figured surface including a cylindrical surface with a small radius r, smaller than R and two transition sections between them, in the area of which there are inlet and outlet openings for the worker body, coaxial with the stator rotor with a gate, and the gate has a length equal to the length of the working chamber of the stator, a width equal to the sum of the small and large radii of cylindrical surfaces, and rotor slot movably, and the groove passes through the axis of rotation of the rotor. The stator is made in the form of a sleeve with an inner diameter equal to twice the large radius with a crescent-shaped insert rigidly mounted in it, the outer surface of which is cylindrical with a radius equal to a large radius, and the radius of the inner cylindrical surface is equal to a small radius.

 A disadvantage of the known design is the complexity of its manufacture due to the complexity of manufacturing curved internal surfaces of the stator.

 The purpose of the invention is to simplify the manufacture of a rotary machine.

 The essence of the invention is based on the fact that it is much easier to process external surfaces having a shape formed by a body of revolution (cylinder) than internal curved surfaces.

, где l = (R + r)/2;
Х_o и Y_o - координаты центра вращения образующей цилиндрической поверхности;
α - половина угла, заключенного между прямыми, исходящими из центра сечения машины к концам переходного участка.This goal is achieved by the fact that in the known rotary machine transition sections have a radius determined from the formula
R _o =

where l = (R + r) / 2;
X _o and Y _o - coordinates of the center of rotation of the generatrix of the cylindrical surface;
α is half the angle enclosed between the straight lines emanating from the center of the machine’s section to the ends of the transition section.

 Among the known sources of information, the authors did not find a solution in which this surface would be represented as formed by three sections, each of which is a cylinder (the rationale below is that the transition section can be described by a circle), which is essential for the claimed design and leads to the achievement of the stated goals (simplification of manufacture) in conjunction with the implementation of the stator in the form of two parts.

 In FIG. 1 shows a rotary machine, cross section; in FIG. 2 and 3 illustrate the rationale that the transition section of the inner surface of the stator in cross section can be described by a circle.

The proposed design consists of a coaxially mounted rotor 1 and a stator, which is a rigid connection of its cylindrical part 2 and a crescent-shaped insert 3, instead of the stator from the prototype (Fig. 2), as well as a gate 4 installed in the groove of the rotor 1 and passing through its axis of rotation . The liner 3 is rigidly connected with its outer surface to the inner surface of the cylindrical part of the stator. Rotor 1 is a shaft with a diameter of d = 2r. The cylindrical part 2 of the stator is a pipe segment with an inner diameter D = 2R. The gate 4, the length of which is equal to the length of the rotor, and the width L = R + r and thickness S, has a rounding of radius S / 2 on the ends sliding along the inner surface of the stator. The gate 4 is installed in the groove of the rotor 1 on a sliding or running landing. The curved surface of the liner is formed by three sections - two extreme (transitional sections (ad) and (cb) with a radius R _o and an average (cd) radius r.

 Two through holes (A — input and B — output) are made in the stator wall, passing both through its cylindrical part 2 and through the sickle-shaped 3, so that the distance (in a straight line) between the channels at the outlet to the stator cavity in the region transition sections (ad and cb) should be no more than R + r.

 The machine operates as follows. Channel A is supplied with gas under pressure. The gas pressure on the gate causes the rotor to rotate, while the chamber 6 expands, and the chamber 7 decreases, the gas from the chamber 7 is pushed through the channel B. Since the distance between the channels at the outlet of them into the cavity is selected no more than R + r, during rotation The rotor does not have direct connections between the input and output channels.

 When the rotor rotates, the working end of the gate separating the expansion and compression chambers is pressed against the stator surface. If necessary, flat sealing plates can be installed at the ends of the gate according to the type of piston rings of internal combustion engines.

In FIG. 3 shows a cross section of the stator, where:
R _n and R _l - the width of the right and left parts of the device;
X ₁ and Y ₁ - coordinates of the end of the transition section at point C;
X ₃ and Y ₃ - coordinates of the end of the transition section at point B;
X ₂ and Y ₂ - the coordinates of the point P, in which R _p = R _l ;
R _o is the radius of the circle describing the transition section;
X _o and Y _o - the coordinates of the center of the circle that describes the transition section;
φ is the current angle measured from the beginning of the transition section;
2 ^. α is the angle to which the arc of the transition section cd (or ad) corresponds.

In FIG. 3 shows in more detail the right transition section at 2 α = 90 ^o . In this case, the axis of symmetry of the section is rotated counterclockwise until the point C in FIG. 4 with the X axis in FIG. 5. Turning to FIG. 3, we give a proof that the transition curve can be formed by a circle.

 When the rotor rotates with the gate, both ends of the gate must come into contact with the stator surface (with a gap determined by the tolerances for the manufacture and assembly of the machine, as well as the conditions of thermal expansion of the parts during operation). This means that the distance between the points of intersection of the line drawn through the axis of the rotor with the inner surface of the stator should be unchanged in all directions and equal to R + r.

We show that this condition is satisfied if the transition sections are described by the Archimedes spiral. The equation of the spiral of Archimedes has the form:
ρ = G˙β, (1) where ρ is the radius vector describing the spiral;
G is a constant that determines the rate of increase of the radius vector;
β is the angle determining the position of the radius vector on the spiral
If β = φ + β _o , then ρ = G (φ + β _o ) = G x
xφ + G ₁ .

In our case (Fig. 5), ρ varies from r to R, and φ from 0 to 2 α, i.e., for φ = 0, G ₁ = r, for φ = 2α, G = (Rr) / 2 α.

Thus, equation (1) takes the form:
ρ = φ ^. (R - r) / 2 α + r. (2)
We define the gate width L, which satisfies equation (2). Since the width of the gate is equal to R _n + R _l , then taking into account the symmetry of the structure:
L = ρ _{2 α -φ} + ρ φ; from here:
L = R + r.

 Let us prove that the Archimedes spiral can be replaced with a high degree of accuracy by an arc of a circle drawn through three points: the ends of the transition curve (points c and b of Fig. 4), and its middle is point P.

Принимая во внимание, что
X₁ = r, X₂ = X₂=

Cosα cos α , X₃ = R cos 2 α
Y₁ = 0, Y₂ = Y₂=

Sinα sin α , Y₃ = R sin 2 α
и обозначив (R + r)/2 = l, находим радиус и координаты центра вращения образующей: R_o ² = l² - 2l (X_o cos α + Y_o sin α) + X_o ² + Y_o ² X₀= -

Y₀=

Погрешность аппроксимации спирали Архимеда окружностью, проходящей через две крайние и среднюю точки переходного участка, определяется как разность длин радиус-векторов, проведенных из центра статора до точек пересечения с окружностью и спиралью:
ε= ρ_o-ρ. Суммарный зазор δ между концами шибера и переходной поверхностью определяется как алгебраическая сумма погрешностей аппроксимации для углов φ и 2α-φ .The coordinates of the center of the circle X _o and Y _o and its radius R _o determine the relations:

Taking into account that
X ₁ = r, X ₂ = X ₂ =

Cosα cos α, X ₃ = R cos 2 α
Y ₁ = 0, Y ₂ = Y ₂ =

Sinα sin α, Y ₃ = R sin 2 α
and denoting (R + r) / 2 = l, we find the radius and coordinates of the center of rotation of the generatrix: R _o ² = l ² - 2l (X _o cos α + Y _o sin α) + X _o ² + Y _o ² X ₀ = -

Y ₀ =

The error of approximation of the Archimedes spiral by a circle passing through the two extreme and middle points of the transition section is determined as the difference between the lengths of radius vectors drawn from the center of the stator to the points of intersection with the circle and the spiral:
ε = ρ _o -ρ. The total gap δ between the ends of the gate and the transition surface is defined as the algebraic sum of the approximation errors for the angles φ and 2α-φ.

.For the spiral of Archimedes:
ρ = r +

.

,
δ = ε_лев + ε_прав = ρ₀(φ-r-

φ+ρ₀(2α-φ)-r-

(2α-φ),

+. Был проведен численный анализ выражения (3) при различных углах α и соотношениях радиусов ротора и статора r/R при R = 100 мм. Анализ показывает, что максимальная погрешность аппроксимации соответствует точкам φ = α /2 и φ = 3/2 α (точки М и N на фиг. 5). Во всех рассмотренных случаях максимальная погрешность δ /R не превышает 2,7 ^. 10^-3. Значения максимальных погрешностей приведены в таблице.For a circle:
ρ $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ = X ² + Y ² , where x, y are the coordinates of the arc point. since X = ρ ₀ Cosφ, Y = ρ ₀ Sinφ, then from the equation (XX ₀ ) ² + (YY ₀ ) ² = R $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ we obtain: (ρ ₀ Cosφ-X ₀ ) ² + (ρ ₀ Sinφ-Y ₀ ) ² = R $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ ,
ρ $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ - 2ρ ₀ (X ₀ Cosφ + Y ₀ Sinφ) = R $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ -X $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ -Y $\genfrac{}{}{0ex}{}{\text{2}}{\text{0}}$ ; from here:
ρ ₀ = (X ₀ Cosφ + Y ₀ Sinφ) +

,
δ = ε _lev + ε _right = ρ ₀ (φ-r-

φ + ρ ₀ (2α-φ) -r-

(2α-φ),

+. A numerical analysis of expression (3) was carried out for various angles α and the ratio of the radii of the rotor and stator r / R at R = 100 mm. The analysis shows that the maximum approximation error corresponds to the points φ = α / 2 and φ = 3/2 α (points M and N in Fig. 5). In all cases considered, the maximum error δ / R does not exceed 2.7 ^. 10 ^-3 . Values of maximum errors are given in the table.

Thus, the transition section of the liner can be made in the form of an arc of a circle with a relative error of the order of 2.7 ^. 10 ^-3 .

 Compared with the prototype, the proposed solution allows you to replace the processing of the inner surface of the stator of complex shape to the processing of the outer cylindrical surface of the liner with subsequent installation of the liner in the cavity of the stator. These operations do not cause technological difficulties.

 This shows that the purpose of the invention is to simplify the manufacture of a rotary machine - achieved.

Claims (1)

A ROTARY MACHINE containing a stator, the inner surface of which is formed by a cylindrical surface with a large radius R and a figured surface including a cylindrical surface with a small radius r << R, and two transition sections between them, in the area of which there are inlet and outlet openings for the working fluid, a rotor coaxial with the stator with a groove and a gate, and the gate has a length equal to the length of the working chamber of the stator, a width equal to the sum of the large and small radii of cylindrical surfaces, and the rotor is installed in the groove with the possibility of movement, and the groove passes through the axis of rotation of the rotor, while the stator is made in the form of a sleeve with an inner diameter equal to 2R, with a crescent-shaped insert rigidly mounted in it, the outer surface of which is made cylindrical with a radius equal to R, and the radius of its inner surface equal to r, characterized in that, in order to simplify the manufacture, the transition sections have a radius R ₀ defined by the formula
R _o =

,
where L = (R + r) / 2;
X ₀ and Y ₀ are the coordinates of the center of rotation of the generatrix of the cylindrical surface;
α is half the angular distance between the lines passing through the ends of each transition section.

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