CN203114703U - Electric submersible pump capable of avoiding fracture failure of pump shaft - Google Patents

Abstract

An electric submersible pump capable of avoiding fracture failure of a pump shaft mainly solves the problem that a pump shaft of an electric submersible pump in the prior art can easily fracture and fail. The electric submersible pump is characterized in that the section of the root portion of a spline on the pump shaft (1) is of a curved surface structure, and the curved surface structure is formed after an inward-concave guide round (3) with an inner circular arc and an outward-convex guide round (2) with an outer circular arc transit smoothly and are connected. The section of the root portion of an inner key groove of a spline sleeve (4) is also of a curved surface structure, wherein the curved surface structure is formed after a groove outward-convex guide round (6) with an outer circular arc and a groove inward-concave guide round (7) with an inner circular arc transit smoothly and are connected. The inward-concave guide round (3) is matched with the groove outward-convex guide round (6). The outward-convex guide round (2) is matched with the groove inward-concave guide round (7). According to the electric submersible pump, the pump shaft and the spline sleeve are improved, stress concentration at the root portion of the spline of the pump shaft and shear deformation to the pump shaft by the spline sleeve can be reduced, and accordingly the fracture failure of the pump shaft can be avoided.

Description

A Submersible Electric Pump That Can Avoid Pump Shaft Fracture and Failure

technical field

The utility model relates to a submersible electric pump.

Background technique

The function of the electric submersible pump is to pump the liquid downhole to the surface. The rotating part of the pump is mainly composed of pump shaft, spline sleeve, key, impeller, thrust washer, shaft sleeve, spacer and shaft elastic ring; the fixed part is mainly composed of guide casing, pump casing, joint, O-shaped It is composed of sealing ring, compression tube and top bearing body. In the safety evaluation and failure analysis of the submersible electric pump unit system, it is found that the pump shaft and impeller have the highest failure rate of the submersible electric pump. The failure mode of the pump shaft is mainly wear and fracture failure, which mainly occurs at the outer end of the pump shaft connecting the spline and the keyway.

Contents of the invention

In order to solve the problems existing in the prior art mentioned in the background technology, the utility model provides a kind of electric submersible pump which can avoid fracture and failure of the pump shaft. The improved scheme can reduce the stress concentration at the spline root of the pump shaft and the shear deformation of the pump shaft caused by the spline sleeve, thereby avoiding the fracture and failure of the pump shaft.

The technical solution of the utility model is: the electric submersible pump which can avoid the fracture and failure of the pump shaft is composed of a pump shaft, a spline sleeve, an impeller, a thrust washer, a shaft sleeve, a spacer sleeve and an elastic retaining ring for the shaft. The rotating unit and the fixed unit composed of the guide casing, the pump casing, the joint, the compression tube and the top bearing body. It is unique in that: the section of the root of the spline on the pump shaft is a curved surface structure, and the curved surface structure is composed of an inner concave guide circle using an inner arc and an outer convex guide circle using an outer arc after a smooth transition; The cross-sectional shape of the root of the inner keyway of the spline sleeve is also a curved surface structure, which is composed of a groove with an outer convex guide circle using an outer arc and a groove with an inner concave guide circle with an inner arc after a smooth transition connection; the inner concave guide The circle coincides with the inner and outer convex guide circles of the groove, and the outer convex guide circle coincides with the inner concave guide circle of the groove.

The utility model has the following beneficial effects: the improved submersible electric pump changes the single outer circular arc at the root of the spline of the pump shaft into a groove with an outer circular arc and a groove with an inner circular arc. The curved surface structure formed by the smooth transition connection of the inner concave guide circle, on the one hand, reduces the stress concentration at the spline root of the pump shaft, improves the torque transmission capacity of the pump shaft, and at the same time prevents the shear deformation of the spline sleeve on the pump shaft, thereby avoiding the pump shaft. Shaft break failure. In addition, the curved structure fitted in the tooth groove of the spline sleeve is beneficial to reduce the formation of initial cracks of the spline sleeve and increase the shear resistance.

Description of drawings:

Fig. 1 is a front sectional view of the pump shaft of the present invention.

Fig. 2 is a side view of the pump shaft of the present invention.

Fig. 3 is a front view of the spline sleeve of the present invention.

Fig. 4 is a side sectional view of the spline sleeve of the present invention.

In the figure, 1-pump shaft, 2-outward convex guide circle, 3-inner concave guide circle, 4-spline sleeve, 5-chamfer, 6-inner and outer convex guide circle in groove, 7-inner concave guide circle in groove.

Detailed ways:

Below in conjunction with accompanying drawing, the utility model is further described:

As shown in Figures 1 to 4, this type of submersible electric pump that can avoid pump shaft fracture and failure includes a pump shaft 1, a spline sleeve 4, an impeller, a thrust washer, a shaft sleeve, a spacer sleeve, and a shaft elastic The rotating unit composed of the retaining ring and the fixed unit composed of the guide casing, the pump casing, the joint, the compression tube and the top bearing body. It is unique in that the section of the root of the spline on the pump shaft 1 is a curved surface structure, and the curved surface structure is connected by a smooth transition between the inner concave guide circle 3 using the inner arc and the outer convex guide circle 2 using the outer arc. After forming; the cross-sectional shape of the root of the inner keyway of the spline sleeve 4 is also a curved surface structure, which is composed of a groove with an outer arc and an inner concave guide circle 7 with an inner arc. ; The inner concave guide circle 3 is consistent with the inner and outer convex guide circle 6 of the groove, and the outer convex guide circle 2 is matched with the inner concave guide circle 7 of the groove.

The reason for the above improvements in this scheme is that the main cause of failure of the pump shaft fracture lies in the connection between the pump shaft and the spline sleeve. This is because the torsional deformation of the pump shaft is much larger than the torsional deformation of the spline sleeve, which makes the pump shaft splines at the outer end of the spline sleeve undergo large elastic deformation, while the pump shaft splines in the spline sleeve have almost no elasticity. Deformation, so that the spline end of the spline sleeve is like scissors, shearing the pump shaft spline under the action of torque, and initial cracks are easily formed on the side of the spline, resulting in plastic fracture failure of the pump shaft. Secondly, the pump shaft and the spline sleeve are in a clearance fit. During the process of transmitting dynamic torque, due to the storage and release of the elastic deformation energy of the pump shaft, frequent impacts and frictions occur at the connection between the pump shaft and the spline sleeve. The instantaneous stress will be very large, especially the stress concentration will occur at the root of the spline of the pump shaft, which will easily form initial cracks and cause the spline connection of the pump shaft to fail. This failure mode increases with the increase of the spline fit clearance and the frequent fluctuation of the transmitted torque, and the probability of failure will increase. Therefore, in this scheme, the single outer circular arc at the root of the pump shaft spline is changed to a curved surface structure formed by a smooth transition between the inner and outer convex guide circles in the groove using the outer arc and the concave inner guide circle in the groove with the inner arc. In this way, on the one hand, the stress concentration at the root of the spline of the pump shaft is reduced, and the shear deformation of the spline sleeve on the pump shaft can be reduced while improving the torque transmission capacity of the pump shaft. Reduced initial crack formation of splined sleeves, resulting in increased shear resistance.

During specific implementation, considering the special environment downhole, the radius of the concave guide circle is limited to 0.2 millimeters, and the radius of the convex guide circle is 0.5 millimeters. In addition, chamfers 5 of 0.3 mm and 45 degrees are used at both ends of the spline grooves of the spline sleeve 4 . The edges and corners are blunted to remove burrs.

Claims (3)

1. A submersible electric pump capable of avoiding fracture and failure of the pump shaft, which consists of a pump shaft (1), a spline sleeve (4), an impeller, a thrust washer, a shaft sleeve, a spacer sleeve, and a shaft circlip The rotating unit and the fixed unit composed of guide casing, pump casing, joint, compression tube and top bearing body are characterized in that: the section of the root of the spline on the pump shaft (1) is a curved surface structure, and the curved surface structure It is composed of a concave guide circle (3) using an inner arc and a convex guide circle (2) using an outer arc after a smooth transition connection; the cross-sectional shape of the root of the inner keyway of the spline sleeve (4) is also a curved surface structure , which is composed of an inner and outer convex guide circle (6) using an outer arc and a concave inner guide circle (7) in a groove using an inner arc after a smooth transition connection; the inner concave guide circle (3) and the inner and outer convex guide circles of the groove The circle (6) coincides, and the convex guide circle (2) coincides with the concave guide circle (7) in the groove. 2. A submersible electric pump capable of avoiding pump shaft fracture and failure according to claim 1, characterized in that: the radius of the inner concave guide circle (3) is 0.2 mm, and the radius of the outer convex guide circle (2) is 0.5mm. 3. A submersible electric pump capable of avoiding fracture and failure of the pump shaft according to claim 2, characterized in that: chamfers (5) are used at both ends of the spline grooves of the spline sleeve (4).

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