CN111457004B - Sliding bearing assembly with radial centralizing and axial thrust functions - Google Patents

Abstract

The invention provides a sliding bearing assembly with radial righting and axial thrust functions, which comprises: the static ring comprises a static ring base body, wherein the static ring base body is provided with a first inner cylindrical surface provided with a first radial friction part along the radial direction and is provided with a first thrust surface and a second thrust surface which are opposite along the axial direction; at least one of the first thrust surface and the second thrust surface is provided with a first axial friction part; the radial moving ring comprises a radial moving ring base body, the radial moving ring base body is provided with a second outer cylindrical surface provided with a second radial friction part along the radial direction, and the first radial friction part and the second radial friction part form a radial friction pair; the axial moving ring comprises an axial moving ring base body, the axial moving ring base body is provided with a third thrust surface provided with a second axial friction part along the axial direction, and the first axial friction part and the second axial friction part form an axial friction pair. The invention is applied to the downhole tool of oil and gas drilling, has longer service life, low cost and high reliability.

Description

Sliding bearing assembly with both radial stabilization and axial thrust function

Technical Field

The invention relates to the technical field of drilling equipment, and in particular to a sliding bearing assembly with both radial straightening and axial thrust functions, which is suitable for downhole drilling tools and instruments.

Background technique

Downhole tools for oil and gas drilling, especially turbine drills, screw drills, rotary guides, vertical drilling systems, downhole generators and other equipment are usually slender rods with small radial dimensions and high ambient temperature and pressure. When tiny particles in the drilling fluid (such as rock cuttings, quartz sand, etc.) enter the radial straightening bearings and axial thrust bearings of these equipment, it is easy to cause rapid wear and premature failure of the bearings. The radial straightening bearings and axial thrust bearings are important components in downhole tools and are also vulnerable parts (the existing bearings rely on drilling fluid cooling and lubrication when working, and have a short life). One of the main contents of the maintenance of downhole drilling tools is to replace the radial straightening bearings and axial thrust bearings.

At present, radial stabilizing bearings and axial thrust bearings of downhole drilling tools are generally set separately, which not only occupies a large space and increases the axial length of the downhole tools, but also the adjustment of the axial clearance of the bearings during maintenance mainly relies on experience, which is difficult, time-consuming and labor-intensive.

For downhole drilling tools, especially the radial stabilizing bearing and axial thrust bearing of downhole power drilling tools, the axial space required for installing the upper radial stabilizing bearing, axial thrust bearing and lower radial stabilizing bearing is large, resulting in a large distance (usually reaching or exceeding 750mm to 1000mm) between the inflection point of the curved housing and the end face of the rotating output shaft (or the inflection point and the drill bit). Since the inclination rate of downhole power drilling tools is inversely proportional to the inflection point distance, the inclination rate of downhole power drilling tools is low, which sometimes cannot meet the needs.

In addition, in other fields, such as electric submersible pumps, there is a submersible electric pump thrust and straightening dual-function wear-resistant bearing, including an upper bearing assembly and a lower bearing assembly; the upper bearing assembly includes an upper bearing seat and an upper thrust bearing installed thereon, and the lower bearing assembly includes an straightening bearing inner ring, an straightening bearing outer ring and a lower bearing seat installed sequentially on the shaft.

The bearing described in this technology is actually a large and complex bearing assembly composed of two sets of independent axial thrust rolling bearings and one set of radial straightening sliding bearings. Although it has the dual functions of axial thrust and radial straightening, the rated load of the upper thrust bearing and the lower thrust bearing in the bearing assembly is very small (only the axial unbalanced force when the submersible electric pump is working) and cannot reach the rated load of the axial thrust bearing of most downhole tools (usually greater than 100.00kN). In addition, the cooling and lubricating medium of the bearing assembly is crude oil, which cannot be applied to downhole drilling tools, because the cooling and lubricating medium of the thrust bearings and straightening bearings in most downhole drilling tools (especially turbodrills and screw drills) is drilling fluid with a solid content of 3% to 5% (including barite powder, rock cuttings particles, etc.), which has particularly high requirements for the wear resistance and life of the bearings. In short, this technology belongs to the field of oil production downhole equipment, not suitable for downhole drilling equipment, and the working conditions of the two are different.

Therefore, it is necessary to provide a new sliding bearing assembly with both radial stabilization and axial thrust functions to better meet the use requirements of modern downhole drilling tools.

It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention.

Summary of the invention

In order to overcome at least one defect in the prior art, the present invention provides a sliding bearing assembly with both radial straightening and axial thrust functions, which greatly reduces the space required for installing radial straightening and axial thrust bearings on downhole drilling tools, shortens the total axial length of the downhole tools, and improves the inclination rate of downhole power drilling tools; at the same time, it improves the concentricity of the rotating shaft and the shell of the downhole tool and the working stability, reduces the vibration frequency and amplitude of the downhole tool, extends the service life of the downhole tool, and can meet the comprehensive use requirements of downhole drilling tools.

In order to achieve the above object, the present invention provides the following technical solutions.

A sliding bearing assembly with both radial straightening and axial thrust functions, the sliding bearing assembly with both radial straightening and axial thrust functions comprising: a stationary ring, a radial movable ring and at least one axial movable ring, the stationary ring comprising a stationary ring base in the shape of a hollow cylinder, the stationary ring base having a first inner cylindrical surface and a first outer cylindrical surface opposite to each other along the radial direction, and having a first thrust surface and a second thrust surface opposite to each other along the axial direction; a first radial friction portion is arranged on the first inner cylindrical surface; a first axial friction portion is arranged on at least one of the first thrust surface and the second thrust surface; the radial movable ring comprises a radial movable ring base in the shape of a hollow cylinder, the The radial dynamic ring base has a second inner cylindrical surface and a second outer cylindrical surface relative to each other along the radial direction, and a second radial friction portion is arranged on the second outer cylindrical surface, and the first radial friction portion and the second radial friction portion form a radial friction pair; the axial dynamic ring includes a ring-shaped axial dynamic ring base, and the axial dynamic ring base has a third thrust surface and a fourth thrust surface relative to each other along the axial direction, and a second axial friction portion is arranged on the third thrust surface, and the first axial friction portion and the second axial friction portion form an axial friction pair, and the axial friction pair includes: any one of: a polycrystalline diamond friction pair and a PDC composite friction pair.

In a preferred embodiment, the material of the radial friction pair includes: any one of cemented carbide and polycrystalline diamond.

In a preferred embodiment, the sliding bearing assembly is used in a guide short section in a push-type rotary guide system, the number of the axial moving ring is one, the stationary ring and the radial moving ring form a pair of radial straightening sliding bearings, and the stationary ring and one of the axial moving rings form a pair of single axial thrust sliding bearings.

In a preferred embodiment, the sliding bearing assembly is used in the transmission shaft of a downhole power drilling tool, the number of the axial moving rings is two, and the stationary ring and the radial moving ring form a pair of radial straightening sliding bearings; the two axial moving rings are respectively arranged on the first thrust surface and the second thrust surface of the stationary ring, and together with the stationary ring form a double axial thrust sliding bearing.

In a preferred embodiment, the number of the axial dynamic ring is one, and the static ring includes: a radial straightening static ring and an axial thrust static ring which are separately arranged, and the sliding bearing assembly is used in the guide short section of the push-type rotary guide system, and the radial straightening static ring includes from the inside to the outside: a first ring body, a shock-absorbing ring and a second ring body.

In a preferred embodiment, the end face of the first ring body of the radial straightening static ring is gap-fitted with the axial thrust static ring, and one end face of the second ring body of the radial straightening static ring is in contact with one end face of the axial thrust static ring; the other end face of the axial thrust static ring is provided with the first axial friction portion; the radial straightening static ring and the radial movable ring form a pair of radial straightening sliding bearings, and the axial thrust static ring and one of the axial movable rings form a pair of single axial thrust sliding bearings.

In a preferred embodiment, an extension portion is formed radially outward at one end of the radial dynamic ring base of the radial dynamic ring, and the extension portion is connected to the axial dynamic ring through a connecting piece, and the radial dynamic ring and the axial dynamic ring together constitute a dynamic ring assembly.

In a preferred embodiment, when the axial friction pair and the radial friction pair are polycrystalline diamond friction pairs, a cast tungsten carbide layer is provided between any friction part of the polycrystalline diamond friction pair and the corresponding substrate, and they are welded together by a pressureless infusion sintering method using welding materials.

In a preferred embodiment, when the axial friction pair is a PDC composite friction pair, any friction part of the PDC composite friction pair is welded on the substrate by shielding gas welding or interference fit.

In a preferred embodiment, when the radial friction pair is a cemented carbide friction pair, a cast tungsten carbide layer is provided between any friction part of the cemented carbide friction pair and its corresponding substrate, and they are welded together by welding material using a pressureless infusion sintering method.

At present, the radial stabilizing bearings and axial thrust bearings of downhole tools (especially downhole power drilling tools) are all separately arranged. The axial space required for installing the upper radial stabilizing bearing, the axial thrust bearing and the lower radial stabilizing bearing is large, resulting in a large distance (usually reaching 750mm to 1000mm) between the inflection point of the bent shell and the end face of the rotating output shaft (or the inflection point and the drill bit), and the inclination rate of the downhole power drilling tool is low (the inclination rate of the downhole power drilling tool is inversely proportional to the inflection point distance).

The embodiment of the present invention provides a sliding bearing assembly with both radial straightening and axial thrust functions. The radial straightening bearing with high wear resistance and the axial thrust bearing are completely integrated together. The strong combination greatly reduces the axial space required for installing the bearing, thereby reducing the axial distance between the inflection point of the curved outer shell and the end face of the rotating output shaft (less than 750mm), and improving the inclination rate of the downhole power drilling tool. In addition, the inner cylindrical surface and the end face (the first thrust face and/or the second thrust face) of the static ring of the present invention are perpendicular to each other. When the downhole tool is working, the static ring will be subjected to radial force and axial force at the same time. The rotating output shaft fixed as a whole with the cylindrical dynamic ring and the disc-shaped dynamic ring by the end face clamping method is subjected to more radial constraints when rotating, and the radial inclination and vibration (including vibration frequency and amplitude) relative to the static ring are smaller, and the concentricity is improved.

With reference to the following description and the accompanying drawings, the specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope thereby.

Features described and/or illustrated with respect to one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments.

It should be emphasized that the term “include/comprises” when used herein refers to the presence of features, integers, steps or components, but does not exclude the presence or addition of one or more other features, integers, steps or components.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the components in the drawings are only for illustration purposes and are used to help understand the present invention. They do not specifically limit the shapes and proportional dimensions of the components of the present invention. Under the guidance of the present invention, those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to specific circumstances. In the drawings:

FIG1 is a schematic cross-sectional view of a static ring of a sliding bearing assembly having both radial straightening and uniaxial thrust functions;

FIG2 is a schematic cross-sectional view of a static ring of a sliding bearing assembly having both radial straightening and uniaxial thrust functions;

FIG3 is a schematic cross-sectional view of a static ring of a sliding bearing assembly having both radial straightening and dual axial thrust functions;

FIG4 is a schematic cross-sectional view of a static ring of a sliding bearing assembly having both radial straightening and dual axial thrust functions;

FIG5 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and uniaxial thrust functions;

FIG6 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and uniaxial thrust functions;

FIG7 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and dual axial thrust functions;

FIG8 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and dual axial thrust functions;

FIG9 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and uniaxial thrust functions;

FIG10 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and uniaxial thrust functions;

FIG11 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and uniaxial thrust functions;

FIG. 12 is a schematic cross-sectional view of a sliding bearing assembly having both radial straightening and uniaxial thrust functions.

Description of reference numerals:

1. Stationary ring; 11. Stationary ring base; 111. Radial straightening stationary ring; 1111. First ring body; 1112. Second ring body; 112. Axial thrust stationary ring; 12. First radial friction portion; 13. First inner cylindrical surface; 14. First axial friction portion; 15. Shock-absorbing ring; 16. First thrust surface; 17. Second thrust surface; 18. Connector;

2. radial dynamic ring; 21. radial dynamic ring base; 211. extension portion; 22. second radial friction portion; 23. second outer cylindrical surface;

3. Axial dynamic ring; 31. Axial dynamic ring base; 32. Second axial friction part;

4. Casting tungsten carbide layer.

Detailed ways

In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

It should be noted that when an element is referred to as being "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and/or" used herein includes any and all combinations of one or more related listed items.

1 to 12 , an embodiment of the present invention provides a sliding bearing assembly having both radial straightening and axial thrust functions. The sliding bearing assembly having both radial straightening and axial thrust functions may include: a stationary ring 1 , a radial dynamic ring 2 and at least one axial dynamic ring 3 .

The stationary ring 1 includes a stationary ring base 11 in a hollow cylindrical shape, and the stationary ring base 11 has a first inner cylindrical surface 13 and a first outer cylindrical surface opposite to each other in the radial direction, and has a first thrust surface 16 and a second thrust surface 17 opposite to each other in the axial direction; a first radial friction portion 12 is arranged on the first inner cylindrical surface 13; and a first axial friction portion 14 is arranged on at least one of the first thrust surface 16 and the second thrust surface 17.

The radial dynamic ring 2 includes a radial dynamic ring base 21 in a hollow cylindrical shape, and the radial dynamic ring base 21 has a second inner cylindrical surface and a second outer cylindrical surface 23 opposite to each other along the radial direction, and a second radial friction portion 22 is provided on the second outer cylindrical surface 23. The first radial friction portion 12 and the second radial friction portion 22 form a radial friction pair. The material of the radial friction pair includes any one of polycrystalline diamond and cemented carbide.

The axial dynamic ring 3 includes an annular axial dynamic ring base 31, and the axial dynamic ring base 31 has a third thrust surface and a fourth thrust surface opposite to each other along the axial direction, and the third thrust surface is provided with a second axial friction portion 32. The first axial friction portion 14 and the second axial friction portion 32 form an axial friction pair. The material of the axial friction pair includes any one of polycrystalline diamond and PDC composite friction portion.

Since the strength of cemented carbide is much lower than that of polycrystalline diamond and PDC, the axial length of the radial aligning bearing can be designed to be very long, with a large contact area and low specific pressure, and cemented carbide can fully meet the needs. Of course, when there is no cost restriction, it is better to use polycrystalline diamond as the material of the radial friction pair, which has a longer service life. However, there are still few manufacturers or individuals who have mastered the processing technology of polycrystalline diamond radial aligning sliding bearings at home and abroad, and the processing cost is relatively high. The contact area of the axial thrust bearing is usually small due to the diameter limitation, the contact area is small, and the specific pressure is high. The strength of cemented carbide cannot meet the needs, so high-strength polycrystalline diamond or PDC is selected to form a polycrystalline diamond friction part, a PDC composite friction part, and then a polycrystalline diamond friction pair and a PDC composite friction pair.

The PDC composite friction part may specifically include: a cemented carbide substrate and a polycrystalline diamond wear-resistant layer with a predetermined thickness arranged on the cemented carbide substrate.

In the implementation manner of the present application specification, by simultaneously arranging two or three pairs of superhard material friction pairs in a set of sliding bearings, the inclination angle and radial displacement of the central axis of the rotating shaft relative to the central axis of the stationary housing are reduced, thereby improving the concentricity of the rotating shaft and the housing and the working stability to a certain extent.

On the whole, the sliding bearing assembly with both radial straightening and axial thrust functions provided by the present application greatly reduces the space required for installing radial straightening and axial thrust bearings for downhole drilling tools, shortens the total length of the downhole tools, and improves the inclination rate of the downhole power drilling tools; at the same time, it improves the concentricity and working stability of the rotating shaft and the shell of the downhole tool, reduces the vibration frequency and amplitude of the downhole tool, extends the service life of the downhole tool, and can meet the comprehensive use requirements of downhole drilling tools.

In this embodiment, different embodiments are developed and explained in detail mainly according to the specific composition, structure, etc. of the stationary ring 1.

1 and 5 , a first embodiment provides a sliding bearing assembly having both radial straightening and uniaxial thrust functions, wherein a cylindrical radial moving ring 2 and a stationary ring 1 form a pair of radial straightening sliding bearings; and a disc-shaped axial moving ring 3 and a stationary ring 1 form a pair of uniaxial thrust sliding bearings.

The material of the first axial friction part 14 of a thrust plane of the stationary ring 1 can be polycrystalline diamond. The material of the first radial friction part 12 arranged on the first inner cylindrical surface 13 of the stationary ring 1 can be cemented carbide. The first axial friction part 14 and the first radial friction part 12 can be welded on the stationary ring substrate 11 by a pressureless infusion sintering method.

The sliding bearing assembly has a compact and simple structure and occupies a small space. It is used in the guide short section of the push-type rotary guide system to center the rotating core shaft and reduce the friction between the end surface and the inner and outer parts when the rotating core shaft and the lower joint rotate relative to the non-rotating outer cylinder, thereby improving the service life of the guide short section.

2 and 6 , a second embodiment provides a sliding bearing assembly having both radial straightening and uniaxial thrust functions, wherein a cylindrical radial moving ring 2 and a stationary ring 1 form a pair of radial straightening sliding bearings; and a disc-shaped axial moving ring 3 and a stationary ring 1 form a pair of uniaxial thrust sliding bearings.

The material of the first axial friction part 14 of a thrust plane of the stationary ring 1 can be PDC composite material, and the first axial friction part 14 can be embedded in the blind hole on the end face of the stationary ring substrate 11 by interference fit; and the material of the first radial friction part 12 on the first inner cylindrical surface 13 of the stationary ring 1 can be polycrystalline diamond, and the first radial friction part 12 can be welded on the first inner cylindrical surface 13 of the stationary ring substrate 11 by pressureless infusion sintering method.

The sliding bearing assembly has a compact and simple structure and occupies a small space. It is used in the guide short section of the push-type rotary guide system to center the rotating core shaft, greatly reduce the friction between the end face and the inner and outer parts when the rotating core shaft and the lower joint rotate relative to the non-rotating outer cylinder, thereby greatly improving the service life of the guide short section.

3 and 7 , a third embodiment provides a sliding bearing assembly having both radial straightening and dual axial thrust functions, wherein a cylindrical radial moving ring 2 and a stationary ring 1 form a pair of radial straightening sliding bearings; two disc-shaped axial moving rings 3 are respectively arranged on the first thrust surface 16 and the second thrust surface 17 of the stationary ring 1, forming a dual axial thrust sliding bearing with the stationary ring 1.

The material of the first axial friction part 14 on the two thrust surfaces of the stationary ring 1 can be polycrystalline diamond, and the first axial friction part 14 can be welded on the two thrust surfaces of the stationary ring substrate 11 by pressureless impregnation sintering. The material of the first radial friction part 12 on the first inner cylindrical surface 13 of the stationary ring 1 can be cemented carbide.

The sliding bearing assembly has a compact and simple structure and requires little space. It is applied to the transmission shaft of downhole power drilling tools to reduce the distance between the inflection point of the bent shell and the end face of the rotating core shaft (or the inflection point and the drill bit), thereby improving the inclination rate and service life of the downhole power drilling tools.

4 and 8 , a fourth embodiment provides a sliding bearing assembly having both radial straightening and dual axial thrust functions, wherein a cylindrical radial moving ring 2 and a stationary ring 1 form a pair of radial straightening sliding bearings; two disc-shaped moving rings are respectively arranged on the first thrust surface 16 and the second thrust surface 17 of the stationary ring 1, forming a dual axial thrust sliding bearing with the stationary ring 1.

The material of the first axial friction part 14 on the two thrust surfaces of the stationary ring 1 can be a PDC composite material, and the first axial friction part 14 can be inserted into the blind holes of the two end surfaces of the stationary ring substrate 11 by interference fit. The material of the first radial friction part 12 on the first inner cylindrical surface 13 of the stationary ring 1 can be polycrystalline diamond, and the first radial friction part 12 can be welded on the first inner cylindrical surface 13 of the stationary ring substrate 11 by a pressureless infusion sintering method.

The sliding bearing assembly has a compact and simple structure and requires little space. It is applied to the transmission shaft of downhole power drilling tools to reduce the distance between the inflection point of the bent shell and the end face of the rotating core shaft (or the inflection point and the drill bit), thereby improving the inclination rate and service life of the downhole power drilling tools.

1 and 9 , a fifth embodiment provides a sliding bearing assembly having both radial straightening and uniaxial thrust functions, wherein a cylindrical radial moving ring 2 and a stationary ring 1 form a pair of radial straightening sliding bearings; and a disc-shaped moving ring 3 and the stationary ring 1 form a pair of uniaxial thrust sliding bearings.

The material of the first axial friction part 14 on the thrust surface of the stationary ring 1 can be polycrystalline diamond, and the material of the first radial friction part 12 set on the first inner cylindrical surface 13 of the stationary ring 1 can be cemented carbide. The first axial friction part 14 and the first radial friction part 12 are welded to the stationary ring substrate 11 by pressureless infusion sintering method.

The cylindrical radial moving ring 2 and the disc-shaped axial moving ring 3 are connected together by a connecting piece 18 to form a sliding bearing moving ring assembly. The connecting piece 18 can be in the form of screws, bolts, rivets, etc.

The sliding bearing (assembly) has a compact and simple structure and occupies a small space. It is used in the guide short section of the push-type rotary guide system. It can center the rotating core shaft, reduce the friction between the end faces and the inner and outer parts when the rotating core shaft and the lower joint rotate relative to the non-rotating outer cylinder, increase the cross-sectional area and bending strength of the rotating core shaft, and thus improve the service life of the guide short section.

2 and 10 , a sixth embodiment provides a sliding bearing assembly having both radial straightening and uniaxial thrust functions, wherein a cylindrical radial moving ring 2 and a stationary ring 1 form a pair of radial straightening sliding bearings; and a disc-shaped axial moving ring 3 and the stationary ring 1 form a pair of uniaxial thrust sliding bearings.

The material of the first axial friction part 14 on the thrust surface of the stationary ring 1 can be a PDC composite material. The first axial friction part 14 can be inserted into the blind hole on the end face of the stationary ring substrate 11 by interference fit. The material of the first radial friction part 12 on the first inner cylindrical surface 13 of the stationary ring 1 can be polycrystalline diamond, and the first radial friction part 12 can be welded on the first inner cylindrical surface 13 of the stationary ring substrate 11 by a pressureless infusion sintering method.

The cylindrical radial moving ring 2 and the disc-shaped axial moving ring 3 are connected together by a connecting piece 18 to form a sliding bearing moving ring assembly. The connecting piece 18 can be in the form of screws, bolts, rivets, etc.

The sliding bearing assembly has a compact and simple structure and occupies a small space. It is used in the guide short section of the push-type rotary guide system to center the rotating core shaft, reduce the friction between the end faces and the inner and outer parts when the rotating core shaft and the lower joint rotate relative to the non-rotating outer cylinder, increase the cross-sectional area and bending strength of the rotating core shaft, and thus greatly improve the service life of the guide short section.

Referring to FIG. 1 and FIG. 11 , a seventh embodiment provides a sliding bearing assembly having both radial straightening and uniaxial thrust functions. The stationary ring 1 of the sliding bearing assembly includes: a radial straightening stationary ring 111 and an axial thrust stationary ring 112 which are separately arranged. The radial straightening stationary ring 111 is in a hollow cylindrical shape, and the end face of the first ring body 1111 is clearance-matched with the axial thrust stationary ring 112 (that is, the end face of the first ring body 1111 does not contact the axial thrust stationary ring 112, and the two end faces of the first ring body 1111 are free), while one end face of the second ring body 1112 of the radial straightening stationary ring 111 is in contact with one end face of the axial thrust stationary ring 112 (when the outer cylinder is assembled and the end face is pressed, the second ring body 1112 is tightly connected with the axial thrust stationary ring 112). The other end face of the axial thrust stationary ring 112 is provided with the first axial friction portion 14. The radial centering static ring 111 and the cylindrical radial moving ring 2 form a pair of radial centering sliding bearings, and the axial thrust static ring 112 and an axial moving ring 3 form a pair of single axial thrust sliding bearings.

The material of the first axial friction part 14 provided on the thrust surface of the axial thrust stationary ring 112 can be polycrystalline diamond. The material of the first radial friction part 12 provided on the first inner cylindrical surface 13 of the radial straightening stationary ring 111 can be cemented carbide. The first axial friction part 14 and the first radial friction part 12 can be welded to the stationary ring substrate 11 by a pressureless infusion sintering method.

In this embodiment, a damping ring 15 may be further provided in the radially stabilizing static ring 111. Specifically, the radially stabilizing static ring 111 may include, from the inside to the outside in the radial direction: a first ring body 1111, a damping ring 15, and a second ring body 1112. The damping ring 15 may be made of fluororubber. The first ring body 1111, the damping ring 15, the second ring body 1112, and the axial thrust static ring 112 together constitute the static ring 1 assembly.

In this embodiment, the axial thrust static ring 112 and the radial centering static ring 111 are separately provided, which can reduce the difficulty of processing on the one hand; on the other hand, when the cylindrical radial dynamic ring 2 is subjected to radial impact force (for example, when the drill bit cuts the rock sideways during directional drilling), the radial impact force will only affect the radial centering static ring 111, but not the axial thrust static ring 112. In particular, after the vibration damping ring (fluororubber spring) is provided in the radial centering static ring 111, the impact force will be greatly reduced.

The cylindrical radial dynamic ring 2 and the disc-shaped axial dynamic ring 3 are connected together by a connector 18 to form a sliding bearing dynamic ring assembly. Specifically, an extension portion 211 is formed radially outward at one end of the radial dynamic ring base 21 of the radial dynamic ring 2, and the extension portion 211 and the axial dynamic ring 3 are connected together by a connector 18 to form a sliding bearing dynamic ring assembly. The connector 18 can be in the form of a screw, a bolt, a rivet, etc.

The sliding bearing assembly has a compact and simple structure and occupies a small space. It is used in the guide short section of the push-type rotary guide system, which can center the rotating core shaft, reduce the friction between the end faces and the inner and outer parts when the rotating core shaft and the lower joint rotate relative to the non-rotating outer cylinder, increase the cross-sectional area and bending strength of the rotating core shaft, and thus improve the service life of the guide short section.

Since a shock-absorbing ring 15 (for example, a fluororubber spring) is provided in the radial straightening static ring 111, the impact force when the guide rib (also called rib plate) contacts the well wall can be effectively reduced, thereby protecting the MWD probe in the rotary steering system and creating favorable conditions for accurately measuring the well inclination angle and well inclination azimuth.

Referring to FIG. 2 and FIG. 12 , a sliding bearing assembly having both radial straightening and uniaxial thrust functions is provided in the eighth embodiment. The stationary ring 1 of the sliding bearing assembly includes: a radial straightening stationary ring 111 and an axial thrust stationary ring 112 which are separately arranged. The radial straightening stationary ring 111 is in a hollow cylindrical shape, and the end face of the first ring body 1111 is clearance-matched with the axial thrust stationary ring 112 (that is, the end face of the first ring body 1111 does not contact the axial thrust stationary ring 112, and the two end faces of the first ring body 1111 are free), while one end face of the second ring body 1112 of the radial straightening stationary ring 111 is in contact with one end face of the axial thrust stationary ring 112 (when the outer cylinder is assembled and the end face is pressed, the second ring body 1112 is tightly connected with the axial thrust stationary ring). The other end face of the axial thrust stationary ring 112 is provided with the first axial friction portion 14. The radial centering static ring 111 and the cylindrical radial dynamic ring 2 form a pair of radial centering sliding bearings, and the axial thrust static ring 112 and an axial dynamic ring 3 form a pair of single axial thrust sliding bearings.

The material of the first axial friction part 14 provided on the thrust surface of the axial thrust static ring 112 can be a PDC composite material, which can be inserted into the blind hole of the end face of the axial thrust static ring 112 by interference fit. The first radial friction part 12 provided on the first inner cylindrical surface 13 of the radial centering static ring 111 can be made of polycrystalline diamond material and welded on the first inner cylindrical surface 13 of the radial centering static ring 111 by pressureless impregnation sintering method.

In this embodiment, a damping ring 15 may be further provided in the radially stabilizing static ring 111. Specifically, the radially stabilizing static ring 111 may include, from the inside to the outside in the radial direction: a first ring body 1111, a damping ring 15, and a second ring body 1112. The damping ring 15 may be made of fluororubber. The first ring body 1111, the damping ring 15, the second ring body 1112, and the axial thrust static ring 112 together constitute the static ring 1 assembly.

In this embodiment, the axial thrust static ring 112 and the radial centering static ring 111 are separately provided, which can reduce the difficulty of processing on the one hand; on the other hand, when the cylindrical radial dynamic ring 2 is subjected to radial impact force (for example, when the drill bit cuts the rock sideways during directional drilling), the radial impact force will only affect the radial centering static ring 111, but not the axial thrust static ring 112. In particular, after the vibration damping ring (fluororubber spring) is provided in the radial centering static ring 111, the impact force will be greatly reduced.

The cylindrical radial dynamic ring 2 and the disc-shaped axial dynamic ring 3 are connected together by a connector 18 to form a sliding bearing dynamic ring assembly. Specifically, an extension portion 211 is formed radially outward at one end of the radial dynamic ring base 21 of the radial dynamic ring 2, and the extension portion 211 and the axial dynamic ring 3 are connected together by a connector 18 to form a sliding bearing dynamic ring assembly. The connector 18 can be in the form of a screw, a bolt, a rivet, etc.

The sliding bearing assembly has a compact and simple structure and occupies a small space. It is used in the guide short section of the push-type rotary guide system. It can center the rotating core shaft, reduce the friction between the end faces and the inner and outer parts when the rotating core shaft and the lower joint rotate relative to the non-rotating outer cylinder, increase the dangerous cross-sectional area and bending strength of the rotating core shaft, and thus greatly improve the service life of the guide short section.

Since a shock-absorbing ring 15 (for example, a fluororubber spring) is provided in the radial straightening static ring 111, the impact force when the guide rib (also called rib plate) contacts the well wall can be effectively reduced, thereby protecting the MWD probe in the rotary steering system and creating favorable conditions for accurately measuring the well inclination angle and well inclination azimuth.

It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and to distinguish similar objects. There is no order of precedence between the two, and they cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

The above descriptions are only several embodiments of the present invention. Those skilled in the art may make various changes or modifications to the embodiments of the present invention based on the contents disclosed in the application documents without departing from the spirit and scope of the present invention.

Claims (5)

1. A sliding bearing assembly with both radial straightening and axial thrust functions, characterized in that it comprises: a stationary ring, a radial dynamic ring and at least one axial dynamic ring, The stationary ring comprises a stationary ring base in a hollow cylindrical shape, wherein the stationary ring base has a first inner cylindrical surface and a first outer cylindrical surface opposite to each other in the radial direction, and has a first thrust surface and a second thrust surface opposite to each other in the axial direction; a first radial friction portion is arranged on the first inner cylindrical surface; and a first axial friction portion is arranged on at least one of the first thrust surface and the second thrust surface; The radial dynamic ring comprises a radial dynamic ring base in a hollow cylindrical shape, wherein the radial dynamic ring base has a second inner cylindrical surface and a second outer cylindrical surface opposite to each other in the radial direction, a second radial friction portion is arranged on the second outer cylindrical surface, and the first radial friction portion and the second radial friction portion form a radial friction pair; The axial dynamic ring comprises an annular axial dynamic ring base, the axial dynamic ring base has a third thrust surface and a fourth thrust surface opposite to each other along the axial direction, the third thrust surface is provided with a second axial friction portion, the first axial friction portion and the second axial friction portion form an axial friction pair, and the axial friction pair comprises: any one of a polycrystalline diamond friction pair and a PDC composite friction pair; The sliding bearing assembly is used in the guide nipple of the push-type rotary guide system, the number of the axial dynamic ring is one, the static ring and the radial dynamic ring form a pair of radial straightening sliding bearings, and the static ring and one of the axial dynamic rings form a pair of single axial thrust sliding bearings; The sliding bearing assembly is used in the transmission shaft of the downhole power drilling tool. The number of the axial dynamic rings is two, and the stationary ring and the radial dynamic ring form a pair of radial straightening sliding bearings; the two axial dynamic rings are respectively arranged on the first thrust surface and the second thrust surface of the stationary ring, and together with the stationary ring form a double axial thrust sliding bearing; The number of the axial dynamic ring is one, the static ring comprises: a radial centering static ring and an axial thrust static ring which are separately arranged, the sliding bearing assembly is used in a guide short section in a push-type rotary guide system, and the radial centering static ring comprises: a first ring body, a shock absorbing ring and a second ring body from the inside to the outside along the radial direction; The end face of the first ring body of the radial centering static ring is in clearance fit with the axial static thrust ring, and one end face of the second ring body of the radial centering static ring is in contact with one end face of the axial static thrust ring; the other end face of the axial static thrust ring is provided with the first axial friction portion; the radial centering static ring and the radial moving ring form a pair of radial centering sliding bearings, and the axial static thrust ring and one of the axial moving rings form a pair of single axial thrust sliding bearings; An extension portion is formed radially outwardly at one end of the radial dynamic ring base of the radial dynamic ring, and the extension portion is connected to the axial dynamic ring through a connecting piece, and the radial dynamic ring and the axial dynamic ring together form a dynamic ring assembly; The cylindrical radial moving ring and the disc-shaped axial moving ring are connected together through a connecting piece to form a sliding bearing moving ring assembly. 2. The sliding bearing assembly with both radial straightening and axial thrust functions as described in claim 1 is characterized in that the material of the radial friction pair includes: any one of cemented carbide and polycrystalline diamond. 3. The sliding bearing assembly with both radial straightening and axial thrust functions as described in claim 2 is characterized in that when the axial friction pair and the radial friction pair are polycrystalline diamond friction pairs, a cast tungsten carbide layer is provided between any friction part of the polycrystalline diamond friction pair and the corresponding substrate, and they are welded together by a pressureless infusion sintering method using welding materials. 4. The sliding bearing assembly with both radial straightening and axial thrust functions as described in claim 2 is characterized in that: when the axial friction pair is a PDC composite friction pair, any friction part of the PDC composite friction pair is welded on the substrate by shielding gas welding or interference fit. 5. The sliding bearing assembly with both radial straightening and axial thrust functions as described in claim 2 is characterized in that: when the radial friction pair is a cemented carbide friction pair, a cast tungsten carbide layer is provided between any friction part of the cemented carbide friction pair and its corresponding substrate, and they are welded together by a pressureless infusion sintering method using welding materials.