RU2230171C1 - Jointed device of helical rotor-driven hydraulic machine - Google Patents

Abstract

FIELD: helical rotor-driven hydraulic machine jointed devices engineering. SUBSTANCE: jointed device of helical rotor-driven hydraulic machine has a shaft, a casing, a saddle, finger, two half-inserts and two blocks, through which axial load and torque are transferred to casing from the shaft. At upper portion of casing longitudinal windows with flat walls are made as well as solid axial aperture. At its lower portion perpendicularly to the axis a through radial aperture is made. End portion of shaft is made with spherical surface, front portion of which interacts with spherical surface of the saddle, and back portion of which interacts with spherical surfaces of half-inserts. By means of half-inserts the shaft is pressed to spherical recess of the saddle, which prevents axial displacement of shaft. In windows of the casing two blocks are mounted, which have planes of sliding for interaction with flat walls of casing windows. Shaft and casing are connected to each other through the saddle, as well as through finger, which is mounted immovably with its middle portion in radial aperture of the shaft, and two blocks are moveably mounted on the ends of the finger. EFFECT: increased transferred moment, higher durability and wear resistance of the assembly due to lesser forces of collapse in the connection, higher loading capability of jointed device with guaranteed strength due to increased distance from the point of force purchase, as well due to absence of axial displacement of shaft, which causes vibrations of jointed connection in case if cyclic loads. 2 cl, 3 dwg

Description

The invention relates to techniques for well construction, and in particular to articulated devices for screw gerotor hydraulic machines (downhole screw motors for drilling oil and gas wells and screw pumps for pumping liquids).

Known articulated device of a screw pump (US patent No. 4907906, publ. 03/13/1990). This device includes a cage with axial and radial holes, a shaft with a through groove having flat walls parallel to the axis of the shaft, a cylindrical pin mounted in the radial holes of the cage and passing through the shaft groove.

This device has several disadvantages. The disadvantage of this device is that the moment from the shaft to the cage is transmitted through a cylindrical finger along the line of contact of the finger with the flat walls of the groove. At large moments in the contact line, large contact stresses arise, which leads to rapid wear of the groove surfaces and to the destruction of the finger.

Another disadvantage of this device is that the axial load from the shaft to the cage is perceived by the finger, and its large values lead to rapid wear of the finger and groove surfaces.

Also known is a synchronous articulated device for transmitting torque from the rotor of a downhole screw motor to the shaft of the support assembly used for directional drilling (RF patent No. 2186189, Mcl ⁶ 7 E 21 V 4/02, F 04 C 2/00 published on July 27, 02, Bull. No. 21). Such a device is the closest analogue to the claimed technical solution and is selected as a prototype. It includes a cage with radial holes and an axial blind hole with a spherical bottom; a shaft with a spherical end part (fifth) interacting with the spherical bottom of the axial hole of the cage, and a through groove having flat walls parallel to the axis of the shaft; a finger installed in the radial holes of the cage and passing through the groove of the shaft; a sleeve located in the groove of the shaft in which the finger is installed. The sleeve is made with flats on the outer surface for interaction with the flat walls of the through radial hole of the shaft.

Known articulated device has several disadvantages, namely:

- the impossibility of transmitting sufficiently large torques due to the small amount of shoulder forces arising from the transmission of rotation;

- structure has a small area of contact (working at _^half the area of the sleeve flats on each side), which is difficult to increase due to possible weakening of the cross section of the shaft, so there arise considerable voltage collapse;

- the shaft can move in the axial direction relative to the casing within the length of the groove, which under cyclic loads leads to the destruction of the hinge;

- the design is not repairable, since the finger is welded to the clip.

An object of the present invention is to provide an articulated device for a screw gerotor hydraulic machine (a downhole screw motor or a screw pump), in which:

- increases the durability of the main parts by increasing their strength;

- reduced wear of the contacting surfaces of crackers and window pads by reducing stresses of their crushing;

- increases the transmitted torque while maintaining the small dimensions of the hinge device;

- it is possible to disassemble the joint for the purpose of repairing it.

The problem is solved in that in the proposed hinge device containing a cage with a blind axial hole, a heel with a spherical surface, a shaft with a spherical end part for interacting with the spherical surface of the heel and a finger, according to the invention, the finger is pressed into the middle part in a radial, through hole of the shaft, perpendicular to its axis, and freely passes through the windows of the holder with end parts, two crackers are freely installed at the ends of the finger, and the crackers are made with parallel planes sliding ia and are placed in the windows of the holder having flat walls parallel to the axis of the holder and interacting with the flat walls of crackers; two half-shells are installed and fixed in the axial hole of the cage, forming a spherical recess that mates with the outer spherical surface of the shaft end part. In addition, the outer surface of the crackers and the inner surface of both half-liners are made conical with angles of deviation from the adjacent surface exceeding the acute angle of a possible circular deflection of the shaft in the cage.

In the prototype, the shaft has the possibility of axial movement relative to the cage, that is, is not rigidly fixed. And in the present invention, the installation of half-liners “locks” the spherical end of the shaft and, thus, a spherical hinge is obtained in which the shaft can rotate freely and transmit torque at the angle of refraction α. In this case, the shaft cannot move along the axis, which increases the rigidity of the mount and thereby reduces the wear of the contacting surfaces of the heel and the thrust bearing and increases their durability.

In the design of the prototype, the contact areas of the sleeve and the walls of the through radial groove are located inside the shaft. Therefore, the contact area between the sleeve and the walls in the shaft is not large enough, and the shoulder action is small. In the proposed design, the contact pads are brought out into the cage, which allows to increase the shoulder of the load application and, accordingly, increases the load capacity of the hinge. When transmitting torque from the shaft to the cage, the flat walls of the cage windows interact with the sliding pads of the crackers, while the number of pads doubles compared to the prototype, which increases the contact area, and therefore, reduces the wear of the contacting surfaces by reducing shear stresses.

The increase in the length of the windows also allows to increase the area of their contact with crackers, which leads to a reduction in shear stresses in comparison with the prototype, due to which the wear of the parts of the hinge device is also reduced.

In the prototype, the finger end parts are welded to the cage, and the middle part rotates freely relative to the sleeve, while the sleeve has the ability to slip inside the through groove perpendicular to the axis of the shaft. In the invention, the middle finger is pressed into the through radial hole of the shaft, which, unlike the prototype, ensures its maintainability.

The invention is illustrated by drawings, where in Fig.1 shows a General view of the hinge device of a screw gerotor hydraulic machine in longitudinal section; figure 2 shows a cross section of a hinge device at the location of the axis and crackers (section a-a in figure 1); figure 3 shows a longitudinal section of the hinge device at the location of the axis and the crackers, combined with a side view (section BB in figure 1).

The hinged device of the screw gerotor hydraulic machine shown in figures 1-3 contains a shaft 1, a clip 2, a heel 3, half-liners 4, crackers 5, finger 6. In the upper part of the clip 2 there is an axial hole G and two symmetrical longitudinal windows D having flat walls parallel to the axis of the holder O ₂ O ₂ . In the axial hole G of the cage 2, a heel 3 is made, made with a spherical surface B, and a shaft 1 is placed. In its lower part there is a through radial hole C, perpendicular to the axis of the shaft O ₁ O ₁ , in which finger 6 is pressed in. At the ends of finger 6 are installed crackers 5 having sliding planes D for interacting with the flat walls of the windows of the holder 2. The end part of the shaft 1 is made with an outer spherical surface B for its front part to interact with the spherical surface of the heel 3, and the back part with spherical surfaces E along 4. uvkladyshey semiloose leaves 4, preventing axial movement of the shaft 1, mounted on a holder 2 with the screws 7. Furthermore, semiloose leaves 4 have an inner conical surface K, which exceeds the refractive deviation angle α. The upper part of the shaft 1 is connected to the driving link (rotor) of the screw gerotor hydraulic machine, engine or pump (not shown) using, for example, a thread. The hinge device of the screw gerotor hydraulic machine can be closed by a cuff 8 and sealed with a rubber ring 9. The cuff 8 is fixed at one end to the sleeve 10 and the other to the shaft 1 with a clamp 11. The lower part of the casing 2 is connected to the driven link of the screw gerotor hydraulic machine (in FIG. . not shown) using, for example, a thread.

The hinged device of a screw gerotor hydraulic machine operates as follows. The leading link of the screw gerotor hydraulic machine (not shown in Fig.) Transfers axial load and torque to shaft 1. The axial load is transmitted from the shaft 1 to the yoke 2 through the heel 3 and the shaft end along the spherical surface B. The torque is transmitted from the shaft 1 to the yoke 2 through the walls of the windows D, crackers 5 with sliding platforms and pin 6. During the precession movement of the shaft 1 with respect to to the holder 2 with a refraction angle α of the axis O ₁ O ₁ relative to the axis O ₂ O ₂ there is a sliding of the sites of crackers 5 and finger 6 along the flat walls of windows D and the rotation of crackers 5 and finger 6 around their axis. The spherical surface of the shaft 1 slides along the spherical surface B of the heels 3 and the spherical surface E of the half-shells 4. Thus, the axis O ₁ O _{1 of the} shaft 1 can deviate from the axis O ₂ O _{2 of the} yoke 2 by an angle α in all planes passing through the axis O ₂ O ₂ clips 2.

The proposed device has several advantages over the known device, namely:

- increase the load capacity (torque) by increasing the shoulder moment of forces;

- reduction of shear stress due to the increase in contact area;

- increasing the strength of the connection due to the use of half-liners;

- the ability to disassemble the hinge with a view to repairing it. The swivel device is used in screw gerotor hydraulic machines, for example in downhole screw motors, when transmitting movement from an eccentrically located rotor (not shown in Fig.) To a coaxially placed shaft of the support unit (not shown in Fig.). The axis O ₁ O _{1 of the} shaft 1 is rotated with respect to the axis O ₂ O _{2 of the} cage 2 by the angle of refraction α. As a rule, two articulated devices are interconnected, while the angle of refraction of the two-link articulated device is doubled.

Thus, the proposed hinge device of a screw gerotor hydraulic machine allows to reduce the wear of parts and extend the service life of the hinge device. This makes it possible to increase the durability of a downhole screw motor and to successfully use it when drilling both direct and directional wells.

Claims (2)

1. The swivel device of a screw gerotor hydraulic machine containing a cage with a blind axial hole, a thrust bearing with a spherical surface, a shaft with a spherical end part for interacting with the spherical surface of the heel and a finger, characterized in that the finger is pressed into the middle part in a radial through hole of the shaft perpendicular to its axis, and freely passes through the window of the holder with end parts, two crackers are freely installed at the ends of the finger, and the crackers are made with parallel sliding planes and placed windows holder having flat walls parallel to the axis of the cage and cooperating with flat walls biscuit, in a blind axial hole and two clips mounted semiloose leaves fastened, forming a spherical recess is matched with the outer spherical surface of the end portion of the shaft. 2. The hinge device according to claim 1, characterized in that the outer surface of the crackers and the inner surface of both half-shells are made conical with angles of deviation from the adjacent surface exceeding the acute angle of a possible circular deflection of the shaft in the cage.

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