CN1292143C - Transmission shaft with metal rubber thrust bearing and rolling bearnig for downhole power drill - Google Patents

Abstract

A downhole motor drive shaft with metal rubber thrust bearings and rolling bearings, which at least includes an upper radial hard alloy sliding bearing, an upper axial metal rubber thrust bearing, a rolling bearing set, and a lower axial metal rubber thrust bearing , anti-drop mechanism, lower radial carbide sliding bearing, outer casing, shaft, etc. There is a pressure balance through hole above the radial carbide sliding bearing at the lower part of the shaft. When the transmission shaft of the present invention is working, the drilling fluid flow through the gap between the friction surfaces of the cemented carbide sliding bearing and the rolling bearing group is appropriate to ensure that the cemented carbide sliding bearing, the metal rubber thrust bearing and the rolling bearing group have a sufficiently long working time under the condition of sufficient cooling and lubrication. life. The invention also has the characteristics of reliable operation, easy start-up, convenient replacement of wearing parts and the like.

Description

Downhole motor drive shaft with metal rubber thrust bearing and rolling bearing

technical field

The invention relates to a transmission shaft of a downhole power drilling tool in the fields of petroleum, mines, coal fields, gas fields, etc., in particular to a transmission shaft of a downhole power drilling tool with a long service life and a metal rubber thrust bearing and a rolling bearing. It belongs to the technical field of mechanical manufacturing.

Background technique

Due to the limitation of the conditions of use, downhole power drilling tools (such as screw drilling tools, turbo drilling tools, etc.) in fields such as petroleum, mines, coal fields, and gas fields are forced to be made into tubular shapes with limited diameters. It is very difficult to design a power drilling tool that can meet the requirements of strength, performance and working life in a limited space. The key to improving the performance of the downhole power drilling tool is to increase the working life of the downhole power drilling tool drive shaft. Numerous domestic and foreign Scientific and technological workers have been committed to research in this area for a long time and have achieved some results, but they are still not very satisfactory. For example, the transmission shafts of turbo drilling tools and screw drilling tools adopt an open structure, and the drilling fluid (mud) is used to cool and lubricate the bearings. Even if the best material and heat treatment process are selected, the average working life of the wearing parts is only 50 to 100 hours. , When the drilling working fluid is well purified, the longest working life of the wearing parts does not exceed 150 hours.

The overall specific structure is shown in Figure 1, the structure of the two-ring rolling bearing group is shown in Figure 5, and the structure of the four-ring rolling bearing group is shown in Figure 4. It is mainly composed of an upper radial hard alloy sliding bearing, a rolling bearing group, a lower radial hard alloy sliding bearing, an outer shell 7, and a shaft 8. Among them, the upper radial hard alloy sliding bearing moving ring 1a, the rolling bearing group moving ring 3b, the lower radial hard alloy sliding bearing moving ring 6a, etc. are sequentially installed on the shaft 8, and the upper radial hard alloy sliding bearing The compression nut of the moving ring 1a is pressed on the shaft 8 to form the rotating part of the transmission shaft; the upper radial hard alloy sliding bearing static ring 1b, rolling bearing group static ring 3c, etc. are sequentially installed in the outer casing 7, and the lower diameter The stationary ring 6b of the cemented carbide sliding bearing is pressed in the outer casing 7 to form a stationary part of the transmission shaft.

When the shaft works in the downhole for a certain period of time, when the D section and the nearby dangerous section are fatigued and fractured, the lower shaft head of the shaft and the drill bit or other tools on it may fall into the well, often causing additional large losses.

Contents of the invention

The purpose of the present invention is to provide a downhole power drilling tool drive shaft with metal rubber thrust bearing and rolling bearing, which has a long service life and is safe to use.

The object of the present invention is achieved like this: a kind of downhole power drill transmission shaft with metal rubber thrust bearing and rolling bearing, it at least comprises shaft, the upper radial carbide sliding bearing that shaft side is arranged in sequence, rolling bearing group, The lower radial carbide sliding bearing and the outer casing arranged outside each bearing. Among them, a metal rubber thrust bearing is arranged between the rolling bearing group and the sliding bearing, and the metal rubber thrust bearing is composed of a thrust bearing moving ring and a thrust bearing static ring, wherein the thrust bearing moving ring is installed on the shaft, and the thrust bearing The static ring is contained in the shell. Metal rubber thrust bearing The two or one axial end faces of the static ring or the moving ring are fixed with wear-resistant and oil-resistant rubber, and the two or one end faces of the moving ring or the static ring are surface hardened, with a hardness of HRC50~ 70. The axial movement of the metal rubber thrust bearing is 1.0mm to 5.0mm.

Metal rubber thrust bearings are arranged on the upper and/or lower parts of the rolling bearing group. Metal-rubber thrust bearings are grade 1 or higher, such as grade 1 to grade 20.

Furthermore, the present invention is provided with an anti-dropping mechanism above the lower radial carbide sliding bearing, between the shaft of the metal rubber thrust bearing and the outer casing, and the diameter of the outer convex shoulder of the inner ring of the anti-dropping mechanism is greater than that of the anti-dropping mechanism The minimum diameter of the inner bore of the outer ring and/or the inner diameter of the stationary ring of the lower radial carbide plain bearing.

A pressure balance through hole is provided on the shaft above the radial hard alloy sliding bearing at the lower part of the shaft, and there may be more than one pressure balance through hole, for example, three.

According to the analysis of the above technical solutions, it can be seen that the present invention has a simple and reasonable structure, has a long service life, and can prevent fatigue damage and fracture of the joint section of the lower radial cemented carbide sliding bearing and the shaft and the nearby dangerous section. The lower shaft head and the drill bit or other tools on it will not fall into the well, so as not to cause greater losses.

Description of drawings

Fig. 1 is a structural schematic diagram of a transmission shaft of a four-ring rolling bearing set according to the present invention.

Fig. 2 is a structural schematic diagram of a hybrid transmission shaft with two-ring rolling bearing sets according to the present invention.

Fig. 3 is a structural schematic diagram of the metal-rubber thrust bearing assembly of the present invention.

Figure 4 is a schematic diagram of the structure of the four-ring rolling bearing group

Figure 5 is a schematic diagram of the structure of a two-ring rolling bearing set

Fig. 6 is a schematic structural diagram of a transmission shaft of a two-ring rolling bearing group in the prior art.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to Fig. 1, 3, the present invention is a kind of downhole motor drive shaft with metal rubber thrust bearing and rolling bearing. It mainly consists of an upper radial carbide sliding bearing, an upper axial metal rubber thrust bearing, a rolling bearing set, a lower axial metal rubber thrust bearing, an anti-drop mechanism, a lower radial carbide sliding bearing, and an outer shell 7, Shaft 8 and so on. Upper radial carbide sliding bearing moving ring 1a, upper axial metal rubber thrust bearing moving ring 2a, rolling bearing group moving ring 3b, lower axial metal rubber thrust bearing moving ring 4a, inner ring 5a of the anti-drop mechanism, lower The radial hard alloy sliding bearing moving ring 6a, etc. are installed on the shaft 8 in turn, and the compression nut close to the upper radial hard alloy sliding bearing moving ring 1a is pressed on the shaft 8 to form the rotating part of the transmission shaft; The upper radial hard alloy sliding bearing static ring 1b, the upper axial metal rubber thrust bearing static ring 2b, the rolling bearing group static ring 3c, the lower axial metal rubber thrust bearing static ring 4b, the outer ring 5b of the anti-fall mechanism, etc. Installed in the outer casing 7, the static ring 6b of the lower radial hard alloy sliding bearing is pressed in the outer casing 7 to form the static part of the transmission shaft. The difference between the embodiment shown in Fig. 2 and Fig. 1 is only the setting of the rolling bearing group, and the other structures are the same.

According to Figures 1 and 2, the key to improving the working life of the drive shaft of the downhole motor is how to improve the life of the wearing parts of the drive shaft. The main wearing parts of the drive shaft of downhole drilling tools are bearings. In the existing transmission shaft structure, only the rolling bearing group bears the axial load, and the drilling fluid flow through the friction surface gap of the rolling bearing group is relatively large, which causes the rolling bearing group to wear out too quickly under the abrasive wear condition of the drilling fluid. The present invention adds 0-20 grades of axial metal rubber thrust bearings on the basis of the existing drive shaft structure, and these metal rubber thrust bearings are assembled on the upper and/or lower parts of the rolling bearing group. The axial play of the metal rubber thrust bearing is 1.0mm to 5.0mm, while the axial play of the rolling bearing group is 0.5mm to 1.0mm. Therefore, after the rolling bearing set wears to a certain extent, the metal rubber thrust bearing and the rolling bearing The group jointly bears the axial load, thereby ensuring that the new drive shaft has a longer working life than the existing drive shaft. Metal rubber thrust bearing The two or one axial end faces of the static ring or the moving ring are fixed with wear-resistant and oil-resistant rubber, and the two or one end faces of the moving ring or the static ring are surface hardened, with a hardness of HRC50~ 70, which makes it have good wear resistance under severe working conditions.

The radial clearance of the radial cemented carbide sliding bearings above and below the rolling bearing group is 0.1mm-0.8mm, the friction surface length of the upper radial carbide sliding bearing is 50-200mm, and the friction surface of the lower radial carbide sliding bearing The length is 100-300mm, so that the metal-rubber thrust bearing and rolling bearing group in the drive shaft can only bear axial load, and only an appropriate amount of drilling fluid containing small particles can enter the bearing cavity to lubricate and cool the bearing , without affecting the spraying effect of the drill bit. The outer surface of the moving ring and the inner surface of the static ring of the radial carbide sliding bearing are inlaid with wear-resistant carbide. The hardness of the carbide is high and the wear resistance is good. long.

In addition, in the present invention, there is a pressure balance through hole 9 at position B above the moving ring 6a of the radial hard alloy sliding bearing on the lower part of the shaft 8 . According to the principle of fluid mechanics, the pressure drop between A and D points ΔP _AD , the pressure drop between A and B points ΔP _AB (the loss of working fluid pressure along the way is very small), the pressure drop between B and C points ΔP _Bc (the pressure at point C is the bottom hole pressure, ΔP _Bc is the pressure drop of the drill bit), the pressure drop between points C and D ΔP _cD , the pressure drop between points A and F ΔP _AF , the pressure drop between points F and E There is the following relationship between the pressure drop ΔP _FE and the pressure drop ΔP _AF between points A and F:

ΔP _AD = ΔP _AB + ΔP _BC + ΔP _CD = ΔP _AF + ΔP _FE + ΔP _ED = ΔP _AB + P _BE + ΔP _ED

According to the above formula, ΔP _AF +ΔP _FE =ΔP _AB +ΔP _BE , ΔP _BC +ΔP _CD =P _BE +ΔP _ED .

Since ΔP _AF , ΔP _CD , and ΔP _BE are all small and can be ignored, there is

ΔP _FE ≈ ΔP _AB , ΔP _ED ≈ ΔP _BC .

Since ΔP _AB is small compared to ΔP _BC , ΔP _FE is also small compared to ΔP _ED .

Since the radial gap between the moving ring 1a and the static ring 1b of the upper radial carbide sliding bearing is 0.1-0.8mm, which is very small compared with the diameter of the inner hole of the shaft 8 Φ20-Φ60mm, the transmission shaft works at a smaller Under the pressure difference ΔP _FE , an appropriate amount of drilling fluid passes through the gap between the friction surfaces of the cemented carbide sliding bearing, metal rubber thrust bearing and rolling bearing group, so as to ensure that the cemented carbide sliding bearing, metal rubber thrust bearing and rolling bearing group are fully cooled and lubricated Have a long enough working life.

In addition, in order to prevent the other parts of the transmission shaft from falling into the well after the shaft breaks from the D section, the utility model has an anti-dropping mechanism. The diameter of the outer convex shoulder of the inner ring of the anti-dropping mechanism of the transmission shaft is larger than the minimum diameter of the inner hole of the outer ring of the anti-dropping mechanism and/or the inner diameter of the static ring of the hard alloy sliding bearing at the bottom of the transmission shaft. When fatigue failure occurs in the section and nearby dangerous sections, the lower shaft head of the shaft and the drill bit or other tools on it may fall into the well. After the present invention has the above-mentioned anti-falling mechanism, it can prevent the rest of the shaft and other parts on the shaft from falling into the well, so as to avoid causing greater losses.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be The schemes are modified or equivalently replaced without departing from the spirit and scope of the technical schemes of the present invention, and all of them shall be covered by the scope of the claims of the present invention.

Claims (10)

1. A downhole power drilling tool drive shaft with metal rubber thrust bearings and rolling bearings, which includes shafts, upper radial hard alloy sliding bearings, rolling bearing sets, and lower radial hard alloy sliding bearings arranged in sequence on the shaft And the outer casing provided outside each bearing is characterized in that: a metal rubber thrust bearing is arranged between the rolling bearing group and the sliding bearing, and the metal rubber thrust bearing is composed of a thrust bearing moving ring and a thrust bearing stationary ring, wherein the thrust The moving ring of the bearing is installed on the shaft, and the static ring of the thrust bearing is installed in the housing. 2. The drive shaft for downhole power drilling tools with metal rubber thrust bearings and rolling bearings according to claim 1, characterized in that: two or one end surface grooves of the static ring or moving ring axial of the metal rubber thrust bearing It is fixed with wear-resistant and oil-resistant rubber, and the two or one axial end faces of the moving ring or the static ring are surface-hardened. 3. The downhole motor drive shaft with metal rubber thrust bearings and rolling bearings according to claim 2, characterized in that its hardness is HRC50-70. 4. The drive shaft of a downhole power drilling tool with metal rubber thrust bearings and rolling bearings according to claim 1, characterized in that: the axial movement of the metal rubber thrust bearings is 1.0 mm to 5.0 mm. 5. The drive shaft of downhole power drilling tool with metal rubber thrust bearing and rolling bearing according to claim 1, 2, 3 or 4, characterized in that the metal rubber thrust bearing is arranged on the upper or lower part of the rolling bearing group. 6. The drive shaft of downhole power drilling tool with metal rubber thrust bearing and rolling bearing according to claim 5, characterized in that: the metal rubber thrust bearing has more than one grade. 7. The drive shaft of downhole power drilling tool with metal rubber thrust bearings and rolling bearings according to claim 5, characterized in that: the set of rolling bearings has more than one stage. 8. The drive shaft of downhole power drilling tool with metal rubber thrust bearings and rolling bearings according to claim 1, characterized in that: above the lower radial hard alloy sliding bearing, there is an anti-dropping device between the shaft and the outer casing. mechanism, the diameter of the outer convex shoulder of the inner ring of the anti-dropping mechanism is greater than the minimum diameter of the inner hole of the outer ring of the anti-dropping mechanism and the inner diameter of the static ring of the lower radial hard alloy sliding bearing. 9. The drive shaft of downhole power drilling tools with metal rubber thrust bearings and rolling bearings according to claim 1 or 8, characterized in that: a pressure balance is set on the shaft above the radial hard alloy sliding bearing at the lower part of the shaft through hole. 10. The drive shaft of a downhole power drilling tool with metal rubber thrust bearings and rolling bearings according to claim 9, characterized in that there are more than one pressure balancing through holes.

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