RU2321768C1 - Screw hydraulic gerotor motor - Google Patents

Abstract

FIELD: oil and gas producing industry.

SUBSTANCE: invention relates to gerotor mechanisms of multistart screw hydraulic motors in which rotor with bit is rotated by fluid medium delivered by pump which are used in drilling oil and gas wells. Proposed screw hydraulic gerotor motor has stator in form of tubular housing with fitted on elastomer, for instance, rubber lining with internal helical teeth, and rotor arranged eccentrically inside stator with external helical teeth whose number is less by one than number of teeth of lining, pitches of helical teeth of lining and rotor are proportional to number of their teeth, end face profiles of lining and rotor are formed by common basic rack with displacement, and profile of said contour is inscribed by equidistant shortened cycloid. Invention contains expressions and relations improving energy characteristics, mainly developed power and torque by providing larger cross section area occupied by working medium at equal contour diameter, value of eccentricity of engagement in mechanism, number of teeth of lining and rotor owing to optimization of value of circumference generatrix radius.

EFFECT: improved energy characteristics.

3 cl, 8 dwg

Description

The invention relates to gerotor mechanisms of screw multi-start hydraulic motors, the rotation of the rotor with a bit in which is carried out by pumping a fluid, for drilling oil and gas wells.

A multi-way gerotor mechanism of a screw hydraulic machine is known, containing elements in the form of a stator and plates fixed therein with internal helical teeth made of elastomer, for example rubber, and a rotor with external helical teeth, the number of teeth in the stator lining being more than the number of rotor teeth per unit , the stator axis is offset relative to the axis of the rotor by an eccentricity equal to half the height of the teeth, and the end profile of the teeth of one of the elements is made as an envelope of the initial contour of the rail, the truncated cycloid equidistant with a displacement, while the end profile of the teeth of another element is made in the form of the envelope of the first element envelope when their centroids are rolled without slipping, and the equidistance value is half the magnitude of the diametrical interference in engagement (RU 2194880 C2, 12.20.2002).

A disadvantage of the known design is the inability to change the interference fit and correct the shape of the teeth of the rotor and stator without changing the outer diameters of the rotor and / or stator.

A known gerotor mechanism comprising a stator with internal helical teeth made of an elastic material, such as rubber, and a rotor with external helical teeth, the number of which is one less than the number of stator teeth, the rotor axis being offset relative to the stator axis by an eccentricity equal to half the radial the height of the teeth, the moves of the helical teeth of the rotor and stator are proportional to their number of teeth.

The stator teeth profile in the end section is made as the envelope of the initial contour of the cycloidal rack, outlined by an equidistant with a radius r _{C1 of the} shortened cycloid, and the profile of the teeth of the rotor in the end section is made as the envelope of the other initial circuit of the cycloidal rack with the equidistant radius R _C2 , made more than R _C1 or the related relation R _C2 = R _C1 + (0.1 ... 0.5) E, where E is the radius of the generating circle equal to the eccentricity (RU 2166603 C1, 05/10/2001).

A variant of the known invention is the implementation of the gerotor mechanism in such a way that the profile of the stator teeth in the end section is made as the envelope of the initial contour of the cycloidal rack, outlined by an equidistant curve with a radius R _{C1 of a} shortened cycloid, and the profile of the teeth of the rotor in the end section is outlined by conjugate arcs of circles, while the tooth protrusion rotor outlined arc radius R _B greater than equidistant stator radius R _C1, or coupled with the relation R _C2 = R _C1 + (0.1 ... 0.5) E, and the rotor tooth gap profile outlined arc radius R _V, which depends on the number of rotor teeth, its outer diameter and the eccentricity (RU 2166603 C1, 10.05.2001).

A disadvantage of the known gerotor mechanism is that these gerotor mechanisms require selective assembly of working pairs due to the need to select the rotor and stator by radial interference.

In addition, during operation due to the occurrence of lateral interference, evenly distributed during convex-concave contact of the rotor tooth with the cavity of the stator tooth, increased wear of the lateral sides of the stator teeth made of elastic material occurs, while due to the presence of radial and lateral interference in the engagement friction forces in the zones of contact of the teeth, creating moments of resistance, preventing the rotation of the rotor around its axis and its planetary motion, which affects its energy characteristics.

Closest to the claimed invention is a gerotor mechanism of a screw hydraulic machine containing a stator and a rotor eccentrically located in it, the teeth of which are in continuous contact and have a difference of their numbers equal to unity, the end profiles of the stator and rotor are formed by a common initial profile of the rail (mesh) with an offset , and the profile of this contour is outlined by the equidistant of the shortened cycloid, while the largest permissible positive and largest negative bias of the rail contour are given by the relation niy:

Δh _n ≤0.73aZ ₂ ^0.5 ,

| Δh _from | ≤1.04aZ ₁ ^0.41 ,

and the permissible value of the contour diameter is limited by:

D _{to min} ≤D _to ≤D _{to max} ,

Where

D _{to max} = D _f1 + 2Δh _n ,

D _{to min} = D _f1 -2Δh _from ,

where Δh _n , Δh _from is the largest allowable positive and greatest negative bias, respectively, of the rail contour,

D _{to max} , D _{to min} - the largest and smallest values of the contour diameter,

a is the eccentricity of the meshing mechanism,

Z _{1, 2} - the number of teeth of the stator and rotor, respectively,

D _f1 is the nominal diameter of the stator troughs in the absence of bias of the initial circuit, which is set by the formula:

D _f1 = 2 (rZ ₂ + a + r _c ),

where Z ₂ - the number of teeth of the rotor,

r is the radius of the rolling circle forming a normal cycloid of the original rail contour,

r _c is the distance from the shortened cycloid to the profile points of the initial rail contour (RU 2232317 C1, 07/10/2004).

A disadvantage of the known design is that with the selected contour diameter D _k , the eccentricity value "a", the numbers Z _{1, 2 of the} teeth of the stator and rotor, respectively, the area of the passage (live) section occupied by the working fluid of the multiple-pass gerotor mechanism cannot be changed and therefore, there is no way to improve energy characteristics, for example, the developed power and torque in the engine for rotating the rotor from the pump fluid supply or the developed pressure and flow rate in the pump for feeding t pile medium due to rotation of the rotor.

The disadvantages of the known construction are explained by the fact that the shape of the initial engagement contour (rail) is standardized and is set essentially in accordance with OST 39-164-84, while the contour diameter D _k can only be changed by replacing the number of teeth Z _{1 of the} stator or eccentricity "a" gearing mechanism, which imposes restrictions on optimizing engine performance.

The technical problem to which the invention is directed is to improve the energy characteristics of a gerotor screw hydraulic motor, in essence, of developed power and torque, by providing a larger cross-sectional area (living) section occupied by the working fluid, with the same eccentricity "a" gear engagement, contour diameter D _k , the number of teeth of the lining Z ₁ and the rotor Z ₂ .

The essence of the technical solution lies in the fact that in a gerotor screw hydraulic motor containing a stator, which is a tubular body with an elastomer cover fixed to it, for example, rubber, with internal helical teeth, and a rotor with external helical teeth eccentrically located inside the stator, the number which are one less than the number of teeth of the lining, the moves of the helical teeth of the lining and rotor are proportional to their number of teeth, the end profiles of the lining and rotor are formed by a common initial contour of the rails ki with an offset, and the profile of this contour is outlined by the equidistant of the shortened cycloid, according to the invention, the end profile of the teeth of the lining of the elastomer is made envelope of a family of circles of radius r _s in the relative motion of the coordinate systems X _OS , Y _OS and X _s , Y _s , with the beginning of the system _with coordinates X, Y is located _from the central longitudinal axis of the electrode, the beginning of the system of coordinates _axes X, Y _axes offset relative to the central longitudinal axis of the electrode at a _w value of the eccentricity between the central longitudinal axes of the electrode and mouth pa, and the center of the generatrix circle r _s located on _axes X axis at a distance R _oc of the start X coordinate _axes system, and Y _axes is given by:

R _oc = r _if + r _s -a _w ,

where r _if is the radius of the valleys of the teeth of the lining, while the rotation angles ψ _c , φ _os of the coordinate systems X _s , Y _s and X _os , Y _os relative to the fixed coordinate system X, Y are related by the relation:

ψ _c = φ _{axes (Z c +1) / Z c} ,

where Z _c is the number of teeth of the lining, and the end profile of the teeth of the rotor is made envelope of the family of profiles of the teeth of the lining in relative motion.

In addition, the coordinates of X _with , _{with a} nominal profile of the lining of the elastomer are determined by the expressions:

X _c = (X _axes cosφ sinφ _{oc oc oc} -I -a _w) cosψ _c + (X _{oc oc} sinφ + Y cosφ _{oc oc)} sinψ _c,

_With Y = - (X _axes cosφ sinφ _{oc oc oc} -I -a _w) sinψ _c + (X _{oc oc} sinφ + Y cosφ _{oc oc)} cosψ _c.

In addition, the radius r _s and the magnitude of the eccentricity a _w between the central longitudinal axes of the plate of elastomer and rotor are related by the ratio:

r _s = (0.618 ... 4.999) and _w .

This embodiment of the gerotor screw hydraulic motor provides a larger cross-sectional area (living) than occupied by the known constructions, occupied by the working fluid with the same contour diameter D _k (equal to twice the value r _{if the} radius of the valleys of the teeth of the lining), the magnitude of the eccentricity of the engagement a _w mechanism, numbers teeth Z _c (plates) and Z _p (rotor) by optimizing the radius r _{s of the} circumference.

In addition, the implementation of a gerotor screw hydraulic motor in such a way that the coordinates X _c , Y _{from the} nominal profile of the lining of the elastomer are determined by the expressions:

_With X = (X _axes cosφ sinφ _{oc oc oc} -I -a _w) cosψ _c + (X _{oc oc} sinφ + Y cosφ _{oc oc)} sinψ _c,

_With Y = - (X _axes cosφ sinφ _{oc oc oc} -I -a _w) sinψ _c + (X _{oc oc} sinφ + Y cosφ _{oc oc)} cosψ _c,

the radius r _s and the magnitude of the eccentricity a _w between the central longitudinal axis of the plate made of elastomer and rotor are related by the ratio:

r _s = (0.618 ... 4.999) a _w ,

additionally reduces hydromechanical losses due to uniform interference in all phases of contact between the teeth of the lining and the rotor, improved compaction along the contact lines and reduced contact loads in the zone of maximum sliding speeds.

Below is the best version of a gerotor screw hydraulic motor for drilling horizontal oil wells.

Figure 1 shows a longitudinal section of the gerotor mechanism of a screw hydraulic motor.

In Fig.2 shows a section aa in Fig.1 across the stator and rotor of the screw hydraulic motor, the ratio of the number of teeth of the rotor lining is 5/6.

Figure 3 shows a diagram of the formation of the end profile of the teeth in the lining.

Figure 4 shows the formation of the end profile of the teeth in the lining, which is outlined as an envelope curve of the set of radii r _s when turning the coordinate systems shown in figure 3, with the following values: r _s = 10.5 mm; a _w = 3.5 mm; r _if = 31.675 mm.

Figure 5 shows the lining and the rotor, calculated according to OST 39-164-84:

D _k = 2r _if ; r _if = 31.675 mm; Δh _1n = 0 (displacement of the initial contour of the rail for the formation of the profile of the teeth of the lining); Δh _2n = 0.6125 mm (offset of the initial contour of the rail for the formation of the profile of the teeth of the rotor); S = 587 mm ² - the cross-sectional area occupied by the working fluid; numbers 0.054; 0.046 and 0.004 denote the interference in pairs in mm at nominal diameters of the troughs D _k = 63.35 mm and the diameter of the rotor D _a = 56.35 mm.

Figure 6 shows an example of a gerotor mechanism of a screw hydraulic motor with the same contour diameter D _k : lining r _if = 31.675 mm from a circle r _s = 11.1 mm; the rotor enveloping the lining, there are no errors in engagement; S = 593 mm ² - the cross-sectional area occupied by the working fluid.

Figure 7 shows an example of the execution of the gerotor mechanism of a screw hydraulic motor with the same contour diameter D _k : lining r _if = 31.675 mm from the circumference r _s = 0.618; a _w = 2.163 mm; the rotor enveloping the lining, there are no errors in engagement; S = 615 mm ² is the cross-sectional area occupied by the working fluid.

On Fig shows an example implementation of the gerotor mechanism of a screw hydraulic motor with the same contour diameter D _to : lining r _if = 31.675 mm from the circumference r _s = 4,999; a _w = 17.5 mm; the rotor enveloping the lining, there are no errors in engagement; S = 592 mm ² is the cross-sectional area occupied by the working fluid.

The rotor screw hydraulic motor contains a stator, which is a tubular housing 1 made of steel 40X GOST 4543-71, with a lining 2 made of elastomer fixed in it, essentially made of rubber IRP-1226-5 TU 2512.003.45055793-98, with internal with helical teeth 3, and a rotor 4 located inside the stator, made of steel 30X13 GOST 5949-75, with external helical teeth 5, the number of which is one less than the number of teeth 3 of the lining 2, the moves of the helical teeth 3 of the lining 2 and the helical teeth 5 of the rotor 4 are proportional their tooth numbers (not shown), and the central Naya longitudinal axis 6 of the rotor 4 and the central longitudinal axis 2 electrode 7 are offset with each other by an amount of eccentricity 8, shown in Figures 1, 2.

3 shows a circuit formation face profile of teeth 3 of the elastomer plates 2, where position 9 is indicated by the coordinate system _axes X, Y _axes.

The essential features of a gerotor screw hydraulic motor is that the end profile of the teeth 3 of the plate 2 of the elastomer is made envelope of a family of circles of radius r _s in the relative motion of the coordinate systems X _OS , Y _OS and X _s , Y _s , while the origin of the coordinate system X _s , Y _c is located on the central longitudinal axis 7 of plate 2, the beginning 9 of the coordinate system X _os , Y _{os is} offset relative to the central longitudinal axis 7 of plate 2 by the amount of eccentricity 8, a _w between the central longitudinal axis 7 of plate 2 and centrally th longitudinal axis 6 of the rotor 4, and the center 10 of the circumference 11, r _s is located on the axis X _OS at a distance of 12, R _oc from the beginning 9 of the coordinate system X _OS , Y _OS and is determined by the expression:

R _oc = r _if + r _s -a _w ,

where r _if is the radius of 13 depressions of the teeth of the lining 2, shown in Fig.3.

In this case, the rotation angles ψ _c , φ _os of the coordinate systems X _s , Y _s and X _os , Y _os relative to the fixed coordinate system X, Y are related by the relation:

ψ _c = φ _{axes (Z c +1) / Z c} ,

where Z _c is the number of teeth of the lining 2, and the end profile of the teeth 5 of the rotor 4 is made envelope of the family of profiles of the teeth 3 of the lining 2 in relative motion, is shown in figure 2, 3, 4.

The essential features of a gerotor screw hydraulic motor is also that the coordinates X _c , Y _{from the} nominal profile of the plate 2 of the elastomer are determined by the expressions:

_With X = (X _axes cosφ sinφ _{oc oc oc} -I -a _w) cosψ _c + (X _{oc oc} sinφ + Y cosφ _{oc oc)} sinψ _c,

_With Y = - (X _axes cosφ sinφ _{oc oc oc} -I -a _w) sinψ _c + (X _{oc oc} sinφ + Y cosφ _{oc oc)} cosψ _c,

the radius 11, r _s and the eccentricity value 8, a _w between the central longitudinal axis 7 of the plate 2 made of elastomer and the central longitudinal axis 6 of the rotor 4 are related by the relation: r _s = (0.618 ... 4.999) a _w , which further reduces the hydromechanical losses due to uniform interference in all phases of contact between the teeth of the lining and the rotor, improvement of compaction along the contact lines and reduction of contact loads in the zone of maximum sliding speeds, is shown in FIGS. 2, 3.

Figure 3, 4 shows an example of profiling point "C" of the lining 2 of the tubular body 1 from the generatrix of a circle of radius r _s .

When designing ask:

r _if is the nominal radius of the circumference of the vertices of the part with external teeth (the circumference of the depressions for the part with internal teeth);

a _w is the center-to-center distance in a pair;

Z _c is the number of teeth of the stator lining;

δ - interference in the rotor pair - stator lining.

An interference fit is obtained by increasing the value of 13, r _if in the formulas for determining the profile of the rotor 4 by a value of 5.

Gerotor screw hydraulic motor operates as follows. Drilling fluid - a clay fluid with abrasive particles, having a density of up to 1500 kg / m ³ , with a content of up to 1% sand, up to 5% of petroleum products is fed to the upper part of the gerotor screw engine through a drill pipe string (not shown).

Under the influence of the differential pressure of the drilling fluid, the rotor 4 performs a planetary movement inside the stator, rolling around with helical teeth 5 along the helical teeth 3 of the plate 2 of elastomer fixed in the tubular body 1, shown in Fig.1, 2.

In this case, the central longitudinal axis 6 of the rotor 4 rotates around the central longitudinal axis 7 of the elastomer plate 2 fixed in the tubular body 1 along a circle of radius a _w , and the rotor 4 rotates around its central longitudinal axis 6 in the opposite direction to the planetary motion shown in figure 2.

A gerotor screw hydraulic motor for rotating the rotor from the pumped fluid supply improves the energy characteristics, essentially the developed power and torque, by providing a larger cross-sectional area (living) occupied by the working fluid, with the same contour diameter, the magnitude of the eccentricity of the gear engagement, numbers teeth of the lining and rotor, due to the optimization of the radius of the generatrix of the circle.

Claims (3)

1. A rotor screw hydraulic motor containing a stator, which is a tubular body with an elastomer lining fixed therein, for example rubber, with internal helical teeth, and a rotor eccentrically located inside the stator with external helical teeth, the number of which is one less than the number of teeth , the moves of the helical teeth of the plate and rotor are proportional to their number of teeth, the end profiles of the plate and rotor are formed by a common initial contour of the rack with an offset, and the profile of this contour is outlined by an equi istantoy curtailed cycloid, characterized in that the end face profile of teeth of the electrode from elastomer made envelope of a family of circles of radius r _s in the relative motion coordinate systems X _axes, Y _oc and X _c, Y _c, wherein X Start coordinate _system, Y _a is located on the the central longitudinal axis of the electrode, the coordinate system of _axes X, Y _oc offset from the central longitudinal axis of the electrode by an amount of eccentricity and _w between the central longitudinal axes of the electrode and of the rotor, and the center of the circumference of r _s is on the X axis _of at a distance R _oc from start _axes coordinate system X, Y _oc and is given by R _oc = r _if + r _s -a _w , where r _if is the radius of the depressions of the teeth of the lining, while the rotation angles ψ _c , φ _os coordinate systems X _s , Y _c and X _os , Y _oc relative to the fixed coordinate system X, Y are related by ψ _c = φ _os (Z _c +1) / Z _c , where Z _c is the number of teeth of the lining, and the end profile of the teeth of the rotor is made envelope of the family of profiles of the teeth of the lining in relative motion. 2. The rotor screw hydraulic motor according to claim 1, characterized in that the coordinates X _c , Y _{c of the} nominal profile of the lining of the elastomer are determined by the expressions X _c = (X _oc cosφ _{oc oc} -Y _oc sinφ -a _w) cosψ _a + (X _oc sinφ _oc + Y _oc cosφ _oc) sinψ _{s, With} Y = - (X _oc cosφ _{oc oc} -Y _oc sinφ -a _w) sinψ _a + (X _oc sinφ _oc + Y _oc cosφ _oc) cosψ _p. 3. The rotor screw hydraulic motor according to claim 1, characterized in that the radius r _s and the eccentricity a _w between the central longitudinal axes of the plate of elastomer and rotor are related by the ratio r _s = (0.618-4.999) a _w .

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