RU2166603C1 - Gerotor mechanism of screw face hydraulic machine - Google Patents

Abstract

FIELD: construction of holes. SUBSTANCE: invention specifically refers to gerotor mechanisms of screw face hydraulic machines drilling oil and gas wells. Gerotor mechanism includes stator with internal helical teeth and rotor with external helical teeth whose number is less by one than that of internal helical teeth of stator. Profile of teeth of stator in face section is made as envelope of starting contour of cycloidal rack of stator outlined by equidistant shortened cycloid and profile of teeth of rotor looks like envelope of another starting contour of cycloidal rack of rotor outlined by equidistant shortened cycloid by certain mathematical expressions. According to another version of implementation profile of teeth of rotor in face section is outlined by conjugate arcs of circles. Profiles of spaces and protrusions of teeth of rotor are outlined by arcs of radii of which one is specified and profile of space of tooth of rotor is outlined by arc which radius is computed by presented mathematical expression. EFFECT: improved energy characteristics, increased wear resistance and prolonged service life of gerotor mechanism of screw face hydraulic machine. 4 cl, 6 dwg

Description

 The invention relates to techniques for the construction of wells, namely, to gerotor mechanisms of screw downhole motors for drilling oil and gas wells, and can be used in screw pumps for oil production and pumping liquids, as well as in general-purpose screw hydraulic motors.

 Known gerotor internal gearing mechanism (USSR patent N 671463, publ. 07.09.93, Bull. N 33 - 36) used in downhole screw motors. Said gerotor mechanism comprises a rotor with external helical teeth and a stator with internal helical teeth. The rotor axis is offset relative to the stator axis by the amount of eccentricity. The difference in the numbers of teeth of the stator and rotor is equal to one, and the height of the teeth is equal to twice the eccentricity. The profiles of the teeth of the rotor and stator in the end section perpendicular to the axis of the mechanism are made in the form of envelopes of the general initial contour, which is an equidistant of a shortened cycloid. This makes it possible to simplify the manufacture of the gerotor mechanism, since rotors and stators with different numbers of teeth are formed by a common initial contour, and their manufacture is carried out with one cutter.

 A disadvantage of the known gerotor mechanism is that it has a limited amount of displacements of the initial rail contour, which does not allow for the adjustment of the size of the mechanism (changing the diameters of the stator and rotor), which limits the technical (energy) characteristics of the mechanism.

 The indicated drawback was partially eliminated in the gerotor mechanism of a helical downhole hydraulic machine (see the scientific and technical journal "Construction of oil and gas wells on land and at sea", Moscow, VNIIOENG, N 3-4, 1997, p. 41, Fig. 2 and 3).

 The gerotor mechanism of a downhole screw hydraulic machine comprises a stator with internal helical teeth made of an elastic material, for example rubber, a metal rotor with external helical teeth, the number of which is one less than the number of stator teeth. The helical teeth of the stator and rotor are in continuous contact with each other. The strokes of the helical lines of the stator and rotor are proportional to their number of teeth. The rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth.

The profiles of the teeth of the stator and rotor in the end section are made as envelopes of the general initial contour of the cycloidal rack, outlined by the equidistant of the shortened cycloid. In this case, the stator tooth profile is formed when the instrumental straight rail is run in along the machine stator initial circumference, the radius of which is r _w1 = rZ ₁ ,
where r is the radius of the rolling circle during the formation of a shortened cycloid;
Z ₁ - the number of stator teeth,
with the displacement of the rack by Δh ₁ . The profile of the rotor tooth is formed when the tool straight line of the same rack is run around the machine initial rotor circumference, the radius of which is equal to r _w2 = rZ ₂ ,
where Z ₂ - the number of teeth of the rotor,
with the displacement of the rail by the value Δh ₂ = Δh ₁ -Δ _d / 2,
where Δ _d is the diametrical interference of the mechanism.

 This allows you to increase the outer diameter of the rotor to create an interference fit on rubber in order to reduce leakage of the working fluid and create a margin for wear in the working bodies (stator and rotor) of the mechanism, and also allows for the correction of the shape of the teeth of the rotor and stator.

However, as practice has shown, the total diametrical interference of the gerotor mechanism Δ _{d is} distributed unevenly over the teeth of the stator. In the convex-convex contact of the protrusion of the rotor tooth with the protrusion of the elastic stator tooth, the reduced radius of curvature of the profiles is much smaller than in the convex-concave contact of the protrusion of the rotor tooth with the cavity of the stator tooth, as a result of which the deformation of the protrusion of the stator tooth is much larger than the deformation of its cavity. This means that the rotor axis is displaced relative to the calculated position in the direction of decreasing the center distance of the mechanism (rotor eccentricity). As a result of this, the calculated kinematics of the gerotor mechanism is violated, wear on the tops of the teeth of the rotor and stator increases, where, in addition to increased contact loads from the interference, the greatest sliding speed takes place due to the maximum distance of this engagement zone from the instantaneous center of rotation of the rotor (from the pole of engagement) .

 In addition, a decrease in interference in the area of the engagement pole of the gerotor mechanism leads to an increase in volumetric leakage of fluid in this area and to a corresponding decrease in the energy characteristics of a screw hydraulic machine.

 The aim of the present invention is to remedy these disadvantages of the known gerotor mechanism of a helical downhole hydraulic machine, improve its energy characteristics, increase wear resistance and durability by improving sealing along the contact lines in the area of the pole of engagement and reducing contact loads in the area of maximum sliding speeds.

The problem is solved in that in the well-known gerotor mechanism of a downhole screw hydraulic machine containing a stator with internal helical teeth made of an elastic material, for example rubber, a rotor with external helical teeth, the number of which is one less than the number of stator teeth, and the stator helix moves and the rotor are proportional to their number of teeth, the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth, the profile of the stator teeth in the end section enii formed as the envelope of the initial contour of the cycloidal rack delineated by the curtailed cycloid equidistance with equidistant radius R _C1, according to the invention, the profile of the teeth in end cross section of the rotor is formed as the envelope of the other initial contour of the cycloidal rack delineated by the curtailed cycloid equidistance described expressions
X _p2 = rψ-Esinψ + R _C2 cosα _p ,
Y _p2 = -r + Ecosψ + R _C2 sinα _p ,
α _p = arctg ((r-Ecosψ) / Esinψ),
where X _p2 , Y _p2 - coordinates of the profile of the rack of the rotor;
r is the radius of the rolling circle;
E is the radius of the generatrix of the circle, equal to the value of the eccentricity;
R _C2 is the radius of the equidistant rotor rail;
ψ is the current angular parameter of the cycloid;
α _p is the profile angle of the rail,
and the radius of the equidistant R _{C2 of the} rotor rail is made larger than the radius of the equidistant R _{C1 of the} stator rail.

The execution of the profile of the rotor teeth in the end section as an envelope of another initial contour of the cycloidal rack with an increased equidistant radius R _C2 compared to the radius of the equidistant cycloidal rack of the stator R _C1 allows an increase in the radius of the protrusion of the tooth of the rotor and to obtain a lateral interference in engagement, which improves the compaction of workers chambers of a screw hydraulic machine in the zone of the engagement pole, where the separation of the cavities of high and low pressure occurs, the energy characteristics of the gerotor mechanism.

Another difference of the gerotor mechanism is that the radius of the equidistant of the rotor bar R _C2 and the radius of the equidistant of the bar of the stator R _C1 are related by the ratio:
R _C2 - R _C1 = (0.1 - 0.5) E.

 When this ratio is fulfilled, lateral interference is obtained within optimal limits.

When R _C2 - R _C1 <0.1E, the effect of an increase in lateral interference is negligible; if R _C2 - R _C1 > 0.5E, then the lateral tightness becomes excessive, which leads to a decrease in the energy characteristics of the gerotor mechanism as a result of an increase in mechanical losses during deformation of the stator elastic teeth.

где D_р - наружный диаметр ротора по выступам зубьев,
причем радиус выступа зуба ротора R_B выполнен больше радиуса эквидистанты рейки статора R_C1.The problem is also solved by the option in which in the well-known gerotor mechanism of a downhole screw hydraulic machine containing a stator with internal helical teeth made of an elastic material, for example rubber, a rotor with external helical teeth, the number of which is one less than the number of stator teeth, and the strokes the helical lines of the stator and rotor are proportional to their number of teeth, the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth, tooth profile in stator end-face section is formed as the envelope of initial contour of the cycloidal rack delineated by the curtailed cycloid equidistance with a radius equidistant R _C1, according to the invention, the profile of the teeth of the rotor in the end-face section outlined by conjugated arcs of circles, the rotor tooth projection profile outlined by arc of radius R _B, and depression profile the rotor tooth is outlined by an arc of radius

where D _p - the outer diameter of the rotor along the protrusions of the teeth,
moreover, the radius of the protrusion of the rotor tooth R _{B is} made larger than the radius of the equidistant stator rail R _C1 .

The profile of the rotor teeth in the end section is defined by the conjugate arcs of circles, and the profile of the protrusion of the tooth of the rotor is outlined by an arc of radius R _B , the profile of the cavity of the tooth of the rotor is outlined by an arc of radius R _v , and the radius R _{B is} made larger than the equidistant radius of the stator cycloid rail R _C1 , allows to increase the radius of the protrusion of the tooth of the rotor and to get in the engagement side interference, which improves the sealing of the working chambers of the screw hydraulic machine in the area of the pole of engagement, where the separation of the polo Tei high and low pressure, increased energy characteristics of the gerotor mechanism.

In addition, the profile of the cavity of the tooth of the rotor defined by an arc of radius R _v allows you to increase the lateral interference in the phase of engagement, when the protrusion of the stator tooth is in contact with the cavity of the tooth of the rotor, which contributes to the additional sealing of the working chambers of the gerotor mechanism.

Another difference of the gerotor mechanism is that the radius of the protrusion of the rotor tooth R _B and the radius of the equidistant of the stator bar R _C1 are related by
R _B - R _C1 = (0.1 - 0.5) E.

 When this ratio is fulfilled, lateral interference is obtained within optimal limits.

When R _B - R _C1 <0.1E, the effect of an increase in lateral interference is negligible; if R _B - R _C1 > 0.5E, then the lateral tightness becomes excessive, which leads to a decrease in the energy characteristics of the gerotor mechanism as a result of an increase in mechanical losses during deformation of the stator elastic teeth.

In FIG. 1 shows a General view of the gerotor mechanism of a helical downhole hydraulic machine in longitudinal section;
in FIG. 2 shows a cross section of the gerotor mechanism along the line AA;
in FIG. 3 shows the formation of the stator profile of the gerotor mechanism from the initial contour of the cycloidal rod with an equidistant radius R _C1 ;
in FIG. 4 shows the formation of the rotor profile of the gerotor mechanism from the initial contour of the cycloidal rail with an equidistant radius R _C2 ;
in FIG. 5 shows a part of the cross-section of the gerotor mechanism along line AA on an enlarged scale;
in FIG. 6 shows a variant of the rotor of the gerotor mechanism of a screw hydraulic machine, the tooth profile of which is formed by circular arcs.

The gerotor mechanism of a downhole screw hydraulic machine (Fig. 1, 2) contains a stator 1 with internal helical teeth 2, a rotor 3 with external helical teeth 4, the number of which is one less than the number of internal helical teeth 2 of stator 1. Internal helical teeth 2 of stator 1 are made of elastic material, for example, from rubber vulcanized to the inner surface of the stator 2. The axis O ₁ - O _{1 of the} stator 1 is displaced relative to the axis O ₂ - O _{2 of the} rotor 3 by an eccentricity E equal to half the radial height h of the teeth 2 and 4. The working centroid ( the beginning Single circumference) of stator 1 of radius a = EZ ₁ refers to working centroid (the initial circumference) of rotor 3 of radius b = EZ ₂ at the pitch P (Fig. 2). The moves of the helical lines T ₁ and T _{2 of the} teeth 2 and 4, respectively, of the stator 1 and rotor 3 are proportional to their number of teeth Z ₁ and Z ₂ (Fig. 1).

The profile of the teeth 2 of the stator 1 in the end section (Fig. 2, 3) is made as the envelope of the initial contour of the cycloidal rail 5 of the stator 1, outlined by the equidistant of the shortened cycloid 6; the profile of the cycloidal rod 5 of the stator 1 is described by the expressions
X _p1 = rψ-Esinψ + R _C1 cosα _p ,
Y _p1 = -r + Ecosψ + R _C1 sinα _p ,
α _p = arctg ((r-Ecosψ) / Esinψ),
where X _p1 , Y _p1 - coordinates of the profile of the stator rail;
r is the radius of the rolling circle;
E is the radius of the generatrix of the circle, equal to the value of the eccentricity;
R _C1 is the radius of the equidistant stator rail;
ψ is the current angular parameter of the cycloid;
α _p is the profile angle of the staff.

The tooth profile 2 of the stator 1 is formed by rolling the tool straight line 7 of the initial contour of the cycloidal rail 5 of the stator 1 along the instrumental circle 8 of the stator 1, the radius of which is equal to r _w1 = rZ ₁ , with the displacement of the initial contour of the cycloidal rail 5 by Δh ₁ to make the diameter D _K stator 1 along the dents 2 equal
D _K = 2 (r (Z ₁ -1) + E + R _C1 + Δh ₁ ).
The end profile of the stator teeth is described by the expressions:
X ₁ = (X _p1 + r _w1 + Δh ₁ ) cosΦ ₁ - (Y _p1 + r _w1 Φ ₁ ) sinΦ ₁ ,
Y ₁ = (X _p1 + r _w1 + Δh ₁ ) sinΦ ₁ - (Y _p1 + r _w1 Φ ₁ ) cosΦ ₁ ,
Φ ₁ = (Y _p1 - (X _p1 + Δh ₁ ) ctgα _p ) / r _w1 ,
where Φ ₁ is the angle of rotation of the stator 1 in contact with the point of the initial contour of the cycloidal rail 5, having the current angular parameter ψ.
The profile of the teeth 4 of the rotor 3 in the end section (Fig. 2, 4) is made as the envelope of the other initial contour of the cycloidal rack 9 of the rotor 3, outlined by the equidistant of the shortened cycloid 6; the profile of the cycloidal rack 9 of the rotor is described by the expressions:
X _p2 = rψ-Esinψ + R _C2 cosα _p ,
Y _p2 = -r + Ecosψ + R _C2 sinα _p ,
α _p = arctg ((r-Ecosψ) / Esinψ),
where X _p2 , Y _p2 - coordinates of the profile of the rack of the rotor;
r is the radius of the rolling circle;
E is the radius of the generatrix of the circle, equal to the value of the eccentricity;
R _C2 is the radius of the equidistant rotor rail;
ψ is the current angular parameter of the cycloid;
α _p is the profile angle of the staff.

A distinctive feature of the rack 9 of the rotor 3 from the rack 5 of the stator 1 is the radius equidistant radius R _C2 , which is made larger than the radius of the equidistant stator rail R _C1 .

центр которой O_v находится на расстоянии ((D_р/2 - 2E) - R_B) от оси O₂ ротора 3 и лежит на радиусе, повернутом относительно оси выступа зуба на угол 180^o/Z₂.It is optimal to fulfill the relation R _C2 - R _C1 = (0.1 - 0.5) E. The tooth profile 4 of the rotor 3 is formed by rolling the tool straight line 10 of the initial contour of the cycloidal rack 9 of the rotor 3 along the instrumental circle 11 of the rotor 3, the radius of which is equal to r _w2 = rZ ₂ , with the offset of the initial contour of the cycloidal rack 9 by Δh ₂ to perform the diameter D _p rotor 3 on the protrusions of the teeth 4 equal
D _p = 2 (r (Z ₂ -1) + E + R _C2 + Δh ₂ ).
The end profile of the teeth of the rotor is described by the expressions
X ₂ = (X _p2 + r _w2 + Δh ₂ ) cosΦ ₂ - (Y _p2 + r _w2 Φ ₂ ) sinΦ ₂ ,
Y ₂ = (X _p2 + r _w2 + Δh ₂ ) sinΦ ₂ - (Y _p2 + r _w2 Φ ₂ ) cosΦ ₂ ,
Φ ₂ = (Y _p2 - (X _p2 + Δh ₂ ) ctgα _p ) / r _w2 .
where Φ ₂ is the angle of rotation of the rotor 3 in contact with the point of the initial contour of the cycloidal rail 9, having the current angular parameter ψ.
Performing the profiles of the teeth 2 of the stator 1 and the teeth 4 of the rotor 3 from different initial contours of the cycloidal racks 5 and 9, differing in the radii of the equidistant R _C1 and R _C2 , allows the protrusion of the tooth 4 of the rotor 3 to be more complete than the profile of the tooth cavity 2 of the stator 1, for thereby ensuring tightness Δ _side profiles at the sides (FIG. 5), but not in the diametrical dimension. In this case, the change in the center distance of the mechanism decreases, the compaction of its working chambers improves, and the greatest interference is realized in the zone of the engagement pole P, where the sliding speeds of the teeth 4 of the rotor 3 and the teeth 2 of the stator 1 are minimal. The same result is achieved in the embodiment of the gerotor mechanism of a helical downhole hydraulic machine (Fig. 1, 2), the cross-section of the rotor of which is shown in Fig. 6. The option provides for the implementation of the profile of the teeth 2 of the stator 1 from the initial contour of the cycloidal rack 5 (Fig. 3), described by the expressions
X _p1 = rψ-Esinψ + R _C1 cosα _p ,
Y _p1 = -r + Ecosψ + R _C1 sinα _p ,
α _p = arctg ((r-Ecosψ) / Esinψ),
where X _p1 , Y _p1 - coordinates of the profile of the stator rail;
r is the radius of the rolling circle;
E is the radius of the generatrix of the circle, equal to the value of the eccentricity;
R _C1 is the radius of the equidistant stator rail;
ψ is the current angular parameter of the cycloid;
α _p is the profile angle of the rail,
when the instrumental straight line 7 of the initial contour of the cycloidal rack 5 of the stator 1 is rolled along the instrumental circle 8 of the stator 1, the radius of which is equal to r _w1 = rZ ₁ , with the initial contour of the cycloid rack 5 displaced by Δh ₁ to make the diameter D _{K of the} stator 1 along the tooth cavities 2 equal
D _K = 2 (r (Z ₁ -1) + E + R _C1 + Δh ₁ ).
The profile of the teeth 4 of the rotor 3 (Fig. 6) is outlined by the conjugate arcs of circles. The protrusion of the tooth 4 of the rotor 3 is defined by an arc of radius R _B , the value of which is greater than the radius of the equidistant of the stator rail R _C1 , and the center O _{B of the} arc R _B is at a distance (D _p / 2 - R _B ) from the axis O _{2 of the} rotor 3. Tooth cavity 4 rotor 3 is outlined by an arc of radius

the center of which O _v is located at a distance ((D _p / 2 - 2E) - R _B ) from the axis O _{2 of the} rotor 3 and lies at a radius rotated relative to the axis of the tooth protrusion at an angle of 180 ^o / Z ₂ .

It is optimal to fulfill the relation R _B - R _C1 = (0.1 - 0.5) E.

 The gerotor mechanism of a helical downhole hydraulic machine works as follows.

When using the gerotor mechanism in a downhole motor, flushing fluid is supplied to the upper part of the gerotor mechanism through a drill pipe string (not shown in FIG.). Under the influence of the unbalanced pressure of the flushing fluid, the rotor 3 makes a planetary motion inside the stator 1, rolling around with its external helical teeth 4 along the internal helical teeth 2 of the stator 1 (Fig. 1, 2). The axis O _{2 of the} rotor 3 rotates about the axis O _{1 of the} stator 1 along the circumference of the radius E counterclockwise, and the rotor 3 itself rotates about its axis O ₂ clockwise. Kinematically, the motion of the rotor 3 relative to the stator 1 can be represented by rolling without sliding the centroid of the rotor 3 of radius b = EZ ₂ along the centroid of the stator 1 of radius a = EZ ₁ with the instantaneous center of rotation of the rotor 3 located at the tangent point of the centroid (mesh pole) P. In the zone of the pole gearing P localized contact lines (pads) separating the cavity of high and low pressure, therefore, the lateral interference created in the gerotor mechanism according to the present invention provides reliable sealing of the high pressure cavities, which Property reduce fluid leakage and improve energy characteristics downhole motor (efficiency, power), as confirmed by bench tests. As a result of the fact that the change in the eccentricity of the rotor 3 due to the diametric interference is reduced, the contact loads in the zone of maximum sliding speeds of the teeth 4 of the rotor 3 along the teeth 2 of the stator 1 are reduced and a corresponding increase in the durability and wear resistance of the gerotor mechanism. The planetary rotation of the rotor 3 is transmitted to the shaft of the support unit and the associated rock cutting tool (not shown in Fig.).

 When using the gerotor mechanism in screw pumps, the rotor 3 is driven into rotation and, rolling around the teeth 2 of the stator 1, converts the mechanical energy of rotation into hydraulic energy of the fluid flow. The kinematics of motion of the rotor 3 of a screw pump and the benefits obtained by using the proposed gerotor mechanism are similar to those described above for a screw motor.

Claims (4)

1. The gerotor mechanism of a downhole screw hydraulic machine, comprising a stator with internal helical teeth made of an elastic material, for example rubber, a rotor with external helical teeth, the number of which is one less than the number of stator teeth, and the strokes of the stator and rotor helical lines are proportional to their number of teeth , the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth, the profile of the stator teeth in the end section is made as the envelope of the original loidalnoy slats delineated curtailed cycloid equidistance with equidistant radius R _C1, characterized in that the profile of rotor teeth in end cross section is formed as the envelope of the other initial contour of the cycloidal rack delineated by the curtailed cycloid equidistance described expressions
X _P2 = rψ-Esinψ + R _C2 cosα _P ,
Y _P2 = -r + Ecosψ + R _C2 sinα _P ,
α _P = arctg ((r-Ecosψ) / Esinψ),
where X _p2 , Y _p2 - coordinates of the profile of the rack of the rotor;
r is the radius of the rolling circle;
E is the radius of the generatrix of the circle, equal to the value of the eccentricity;
R _C2 is the radius of the equidistant rotor rail;
ψ is the current angular parameter of the cycloid;
α _P - profile angle of the staff,
and the radius of the equidistant R _{C2 of the} rotor rail is made larger than the radius of the equidistant R _{C1 of the} stator rail. 2. The gerotor mechanism according to claim 1, characterized in that the radius of the equidistant rod of the rotor R _C2 and the radius of the equidistant rod of the stator R _C1 are related by
R _C2 = R _C1 + (0.1 - 0.5) E. 3. The gerotor mechanism of a downhole screw hydraulic machine, comprising a stator with internal helical teeth made of an elastic material, for example rubber, a rotor with external helical teeth, the number of which is one less than the number of stator teeth, and the strokes of the stator and rotor helix are proportional to their number of teeth , the rotor axis is offset relative to the stator axis by an eccentricity equal to half the radial height of the teeth, the profile of the stator teeth in the end section is made as the envelope of the original loidalnoy slats delineated curtailed cycloid equidistance with equidistant radius R _C1, characterized in that the profile of rotor teeth in end cross section outlined conjugated arcs of circles, the projection of the rotor tooth profile is outlined _in arc radius R, the tooth gap profile of the rotor radius arc delineated:

where D _p - the outer diameter of the rotor along the protrusions of the teeth;
Z ₂ - the number of teeth of the rotor;
E - eccentricity,
and the radius R _{B of the} arc of the protrusion of the rotor tooth is made larger than the radius of the equidistant R _{C1 of the} stator rail. 4. The gerotor mechanism according to claim 3, characterized in that the radius R _B of the arc of the rotor tooth projection and equidistant slats radius R _C1 of the stator are related by
R _B = R _C1 + (0.1 - 0.5) E.

Images