A method and structure for preventing shaft scaling and resisting axial impact

Abstract

The present invention discloses a method and structure for preventing shaft scaling and resisting axial impact. The present invention is to arrange a connecting pipe outside the transmission shaft, and to arrange a bearing between the inner circle of the connecting pipe and the outer circle of the transmission shaft. The outer circle of the bearing and the connecting pipe have an interference fit, and the inner circle of the bearing and the transmission shaft have a clearance fit. A group of sand discharge grooves are arranged on the inner circle of the bearing, and sand and scale are scraped from the outer circle of the transmission shaft into the sand discharge grooves through the edges of the sand discharge grooves, and then the sand and scale scraped into the sand discharge grooves are discharged from one end of the bearing by the water flowing through the sand discharge grooves. The present invention adopts a connecting pipe to offset the large axial impact force, and a bearing to offset the radial impact force, which is not easy to be damaged and can meet the large impact load effect during the instrument downhole process. It is also suitable for the structural arrangement of other downhole instruments.

Description

Technical Field

[0001] The invention relates to a method and a structure for preventing shaft scaling and resisting axial impact, belonging to the technical field of downhole instrument structures. Background Art

[0002] The shaft is generally supported and limited by bearings, and needs to work in a good sealing environment and an appropriate amount of lubrication environment. There are also standard requirements for the installation space. The instruments used for oil field testing are generally non-standard designs, and the support structure of the transmission shaft is generally sealed inside the instrument with seals. However, there are also support structures exposed to the outside, which are easily stuck or even damaged due to long-term impact of large loads, chemical effects of corrosive substances in oil-water mixtures, landfill of silt and surface scaling, which brings huge workload to product maintenance. Conventional and standard bearing support methods are not suitable for underground use environments. Therefore, there are still deficiencies in the existing technology and further improvements are needed. Summary of the invention

[0003] The purpose of the present invention is to provide a method and structure for preventing shaft scaling and resisting axial impact, so as to solve the problems that the existing support method is not resistant to impact, corrosion, sand and scaling, thereby overcoming the shortcomings of the prior art.

[0004] To achieve the above object, the present invention adopts the following technical solution:

[0005] The present invention provides a method for preventing shaft scaling and resisting axial impact. The method comprises the following steps: a connecting pipe is arranged outside the transmission shaft, a bearing is arranged between the inner circle of the connecting pipe and the outer circle of the transmission shaft, the outer circle of the bearing and the connecting pipe are interference fit, and the inner circle of the bearing and the transmission shaft are clearance fit; and a group of sand discharge grooves are arranged on the inner circle of the bearing, sand and scale are scraped from the outer circle of the transmission shaft into the sand discharge grooves through the edges of the sand discharge grooves, and the sand and scale scraped into the sand discharge grooves are discharged from one end of the bearing by water flowing through the sand discharge grooves.

[0006] In the above method for preventing shaft scaling and resisting axial impact, the bearing is a single-ring sliding bearing, and the bearing is made of corrosion-resistant and wear-resistant material; the matching clearance between the inner circle of the bearing and the transmission shaft is 0.01 to 0.082 mm.

[0007] In the aforementioned method for preventing shaft scaling and resisting axial impact, a load-bearing boss is arranged on the inner circle of the connecting tube, and the axial impact force is transmitted through the load-bearing boss and the load-bearing shoulder of the outer circle of the transmission shaft; the axial impact force is dissipated through the gap δ between the nut arranged at the left end of the transmission shaft and the left end face of the transmission shaft, thereby preventing the bearing from being subjected to axial impact.

[0008] In the aforementioned method for preventing shaft scaling and resisting axial impact, a positioning groove is provided on the nut, and the nut is fixedly connected to the transmission shaft via a positioning pin provided at the positioning groove to prevent the nut from rotating or loosening due to axial impact.

[0009] A structure for preventing shaft scaling and resisting axial impact of the present invention, which is constructed according to the above method and used for the above method, includes a transmission shaft, a connecting pipe is arranged outside the transmission shaft; a pair of bearings are arranged between the connecting pipe and the transmission shaft; and a group of sand discharge grooves evenly distributed along the circumference are arranged on the inner ring of the bearing.

[0010] In the above structure, the bearing is a single-ring sliding bearing made of corrosion-resistant and wear-resistant material; the sand discharge groove is a rectangular groove, and the sand discharge groove is set in the axial direction.

[0011] In the above structure, driving grooves are respectively provided at both ends of the transmission shaft; a nut is provided at the left end of the transmission shaft, and the nut is threadedly connected to the transmission shaft; the nut is positioned and connected to the transmission shaft via a positioning pin.

[0012] In the above structure, a gap δ is provided between the right end surface of the nut and the left end surface of the transmission shaft.

[0013] In the above structure, a load-bearing shoulder is provided at one end of the outer circle of the transmission shaft.

[0014] In the above structure, a load-bearing boss is provided on the inner circle of the connecting pipe.

[0015] Due to the adoption of the above technical scheme, compared with the prior art, the present invention has the following characteristics: the transmission shaft is fixed on the connecting pipe by a nut, the transmission shaft can move axially within a small range and can also rotate; the nut is fixed on the transmission shaft by a locating pin to prevent the nut from loosening due to rotation and impact; the bearing is installed at both ends of the connecting pipe, and a sand discharge groove is processed on the inner cylindrical surface of the bearing; the sand discharge method can be through the extrusion of sand and scale or the flushing and discharge of scale by water flowing through the sand discharge groove and the sand discharge hole during the movement of the instrument; the bearing is made of tin bronze or other corrosion-resistant and wear-resistant materials; the bearing and the transmission shaft are clearance-fitted, and the single-side clearance is (0.01~0.082) mm; the present invention adopts a connecting pipe to offset the large axial impact force, and the bearing offsets the radial impact force, which is not easy to be damaged and can meet the large impact load effect during the instrument going down the well. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the structure of the present invention;

[0017] Figure 2 yes Figure 1 The main view;

[0018] Figure 3 It is a structural schematic diagram of the bearing of the present invention;

[0019] Figure 4 It is a structural schematic diagram of the transmission shaft of the present invention

[0020] Figure 5 It is a structural schematic diagram of the connecting pipe of the present invention.

[0021] The markings in the attached drawings are: 1-transmission shaft, 2-connecting pipe, 3-bearing, 4-sand discharge groove, 5-driving groove, 6-nut, 7-locating pin, 8-load-bearing shoulder, 9-load-bearing boss. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0023] A method for preventing shaft scaling and resisting axial impact of the present invention, as Figure 1 to Figure 5 As shown, the method is that a connecting pipe 2 is arranged outside the transmission shaft 1, a bearing 3 is arranged between the inner circle of the connecting pipe 2 and the outer circle of the transmission shaft 1, the outer circle of the bearing 3 is interference fit with the connecting pipe 2, and the inner circle of the bearing 3 is clearance fit with the transmission shaft 1; and a group of sand discharge grooves 4 are arranged on the inner circle of the bearing 3, and the sand and dirt on the outer circle of the transmission shaft 1 are scraped into the sand discharge groove 4 through the edges of the sand discharge groove 4, and then the sand and dirt scraped into the sand discharge groove 4 are discharged from one end of the bearing 3 through the water flowing through the sand discharge groove 4. The bearing 3 is a single-ring sliding bearing, and the bearing is made of corrosion-resistant and wear-resistant materials; the matching clearance between the inner circle of the bearing and the transmission shaft is 0.01-0.082mm. A bearing boss 9 is arranged on the inner circle of the connecting pipe 2, and the axial impact force is transmitted through the bearing boss 9 and the bearing shoulder 8 of the outer circle of the transmission shaft 1; the axial impact force is resolved by the gap δ between the nut 6 arranged at the left end of the transmission shaft 1 and the left end face of the transmission shaft 1, so as to prevent the shaft transmission shaft 1 from being subjected to axial impact. A positioning groove is provided on the nut 6, and the nut 6 is fixedly connected to the transmission shaft 1 via a positioning pin 7 provided at the positioning groove to prevent the nut 6 from rotating or loosening due to axial impact.

[0024] A structure for preventing shaft fouling and resisting axial impact of the present invention, which is constructed according to the above method and used in the above method, is as follows: Figure 1 to Figure 5 As shown, the structure includes a transmission shaft 1, and a connecting pipe 2 is disposed on the outer cover of the transmission shaft 1; a pair of bearings 3 are disposed between the connecting pipe 2 and the transmission shaft 1; Figure 3 As shown, the inner ring of the bearing 3 is provided with a group of sand discharge grooves 4 evenly distributed along the circumference. The bearing 3 is a single-ring sliding bearing made of corrosion-resistant and wear-resistant materials; the sand discharge groove 4 is a rectangular groove, and the direction of the sand discharge groove 4 is axial. Figure 4 As shown, the two ends of the transmission shaft 1 are provided with driving grooves 5 respectively; one end of the outer circle of the transmission shaft 1 is provided with a bearing shoulder 8. The left end of the transmission shaft 1 is provided with a nut 6, which is threadedly connected to the transmission shaft 1; the nut 6 is positioned and connected to the transmission shaft 1 through a positioning pin 7. There is a gap δ between the right end surface of the nut 6 and the left end surface of the transmission shaft 1. The connecting pipe is as shown in FIG. Figure 5 As shown, a load-bearing boss 9 is provided on the inner circle of the connecting pipe 2.

[0025] Working process and principle of the present invention

[0026] like Figure 1 to Figure 5As shown, a bearing 3 is provided in the connecting tube 2. The bearing 3 is made of tin bronze or other corrosion-resistant and wear-resistant materials. Four sand-discharging grooves 4 are evenly distributed on the bearing 3. Sand-discharging holes can also be processed on the connecting tube 2. A driving groove 5 is processed on the end face of the transmission shaft 1 for transmitting rotational power. The transmission shaft 1 is passed through the connecting tube 2. A nut 2 is used at one end of the transmission shaft 1 to limit axial movement. The nut 6 is fixed to the transmission shaft 1 with a positioning pin 7 to prevent the nut 6 from loosening. The connecting tube 2 is processed with threads and can be connected to the test instrument. Both ends of the transmission shaft 1 are processed with driving grooves 5 and can be connected to the test instrument.

[0027] During specific operation, the transmission shaft 1 can move axially within a limited range δ, or it can rotate. When the transmission shaft 1 is impacted by a huge axial force to the left, the axial force is resolved by the load-bearing shoulder 8 on the transmission shaft 1 and the end face of the load-bearing boss on the inner circle of the connecting tube 2, thereby avoiding the bearing 3 from being subjected to stress. When the rotational power is transmitted to the transmission shaft 1 through the driving groove 5, the transmission shaft 1 starts to rotate and drives the test instrument connected to the transmission shaft 1 to rotate together. At this time, the bearing 3 plays the role of a rotation support. A sand discharge groove 4 is machined on the contact surface between the bearing 3 and the transmission shaft 1. When there is sand or scale on the contact part, the sand and scale are first scraped into the groove through the sand discharge groove 4, and then discharged from one end of the bearing 3 by extrusion.

[0028] The present invention adopts a connecting pipe to offset the large axial impact force, and a bearing to offset the radial impact force, which is not easy to be damaged and can meet the large impact load effect during the instrument downhole process. It is also suitable for the structural arrangement of other downhole instruments.

Claims

1. A structure for preventing shaft scaling and resisting axial impact, characterized in that: The invention comprises a transmission shaft (1), wherein the transmission shaft (1) is provided with a connecting pipe (2) on its outer sleeve; a pair of bearings (3) are provided between the connecting pipe (2) and the transmission shaft (1); and a group of sand discharge grooves (4) evenly distributed along the circumference are provided on the inner ring of the bearing (3); The bearing (3) is a single-ring sliding bearing made of corrosion-resistant and wear-resistant material; the sand discharge groove (4) is a rectangular groove, and the sand discharge groove (4) is arranged in an axial direction; The transmission shaft (1) is provided with a driving groove (5) at both ends; a nut (6) is provided at the left end of the transmission shaft (1), and the nut (6) is threadedly connected to the transmission shaft (1); the nut (6) is positioned and connected to the transmission shaft (1) via a positioning pin (7); A gap δ is provided between the right end surface of the nut (6) and the left end surface of the transmission shaft (1); One end of the outer circle of the transmission shaft (1) is provided with a load-bearing shoulder (8); The inner circle of the connecting pipe (2) is provided with a load-bearing boss (9); The outer circle of the bearing (3) and the connecting pipe (2) are interference fit, and the inner circle of the bearing (3) and the transmission shaft (1) are clearance fit; sand and dirt are scraped from the outer circle of the transmission shaft (1) into the sand discharge groove (4) through the edge of the sand discharge groove (4), and the sand and dirt scraped into the sand discharge groove (4) are discharged from one end of the bearing (3) by water flowing through the sand discharge groove (4); The axial impact force is transmitted through the load-bearing boss (9) and the load-bearing shoulder (8) on the outer circle of the transmission shaft (1); the axial impact force is absorbed through the gap δ between the nut (6) provided at the left end of the transmission shaft (1) and the left end surface of the transmission shaft (1), thereby preventing the bearing (3) from being subjected to axial impact.

2. The structure for preventing shaft scaling and resisting axial impact according to claim 1, characterized in that: The clearance between the inner circle of the bearing (3) and the transmission shaft (1) is 0.01 to 0.082 mm.

3. The structure for preventing shaft scaling and resisting axial impact according to claim 1, characterized in that: The nut (6) is provided with a positioning groove and is fixedly connected to the transmission shaft (1) via a positioning pin (7) provided at the positioning groove, so as to prevent the nut (6) from rotating or loosening due to axial impact.

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