CN-117307016-B - Transmission shaft assembly for screw drilling tool

CN117307016BCN 117307016 BCN117307016 BCN 117307016BCN-117307016-B

Abstract

The invention provides a transmission shaft assembly for a screw drilling tool, which comprises a mandrel, a shell sleeved on the mandrel, a thrust bearing group used for transmitting axial force, a deep groove ball bearing group used for inhibiting radial vibration of the mandrel, and a sealing assembly arranged between the mandrel and the shell, wherein the sealing assembly comprises a first floating isolation ring, a second floating isolation ring and a sealing element which are sequentially and alternately distributed from top to bottom, a first lubrication cavity and a second lubrication cavity are respectively formed between the first floating isolation ring, the second floating isolation ring and the sealing element in the axial direction and used for filling lubricating oil, the thrust bearing group and the deep groove ball bearing group are both arranged in the second lubrication cavity, the deep groove ball bearing group is arranged at the lower end of the thrust bearing group, and the first floating isolation ring and the second floating isolation ring can axially move when the lubricating oil expands at high temperature, so that the lubricating oil in the second lubrication cavity can be isolated.

Inventors

ZHENG DESHUAI
LIU JIANHUA
ZHAO XIANGYANG
LI MENGGANG
CHENG GUANGMING

Assignees

中国石油化工股份有限公司
中石化石油工程技术研究院有限公司

Dates

Publication Date: 20260505
Application Date: 20220620

Claims (10)

1. A drive shaft assembly for a screw drilling tool, comprising: A mandrel (1); a shell (2) sleeved on the mandrel; A thrust bearing set (3) for transmitting axial forces; Deep groove ball bearing set (4) for suppressing radial vibrations of the spindle (1), and The sealing assembly is arranged between the mandrel (1) and the shell (2) and comprises a first floating isolation ring (51), a second floating isolation ring (52) and a sealing element (53) which are sequentially distributed at intervals from top to bottom, wherein a first lubrication cavity (6) and a second lubrication cavity (7) are respectively formed among the first floating isolation ring (51), the second floating isolation ring (52) and the sealing element (53) in the axial direction and are used for filling lubricating oil; The thrust bearing group (3) and the deep groove ball bearing group (4) are both installed in the second lubrication cavity (7), the deep groove ball bearing group (4) is located at the lower end of the thrust bearing group (3), and the first floating isolation ring (51) and the second floating isolation ring (52) can move axially when lubricating oil expands at high temperature, so that isolation can be formed on the lubricating oil in the second lubrication cavity (7).
2. The drive shaft assembly for a screw drilling tool according to claim 1, wherein an outer ring of the deep groove ball bearing set (4) is in interference fit with the housing (2), and an inner ring of the deep groove ball bearing set (4) is in interference fit with the mandrel (1).
3. Drive shaft assembly for a screw drilling tool according to claim 1 or 2, characterized in that a TC radial bearing is mounted between the lower end of the housing (2) and the spindle (1), the TC radial bearing comprising a TC outer sleeve (81) fixedly connected to the housing (2) and a TC inner sleeve (82) fixedly connected to the spindle (1), The sealing element is arranged between the TC outer sleeve (81) and the TC inner sleeve (82).
4. A drive shaft assembly for a screw drilling tool according to claim 3, characterized in that a gap is left between the TC outer jacket (81) and the TC inner jacket (82) in the radial direction so that radial vibrations of the spindle (1) are transmitted to the housing (2) through the deep groove ball bearing set (4).
5. A drive shaft assembly for a screw drilling tool according to claim 3, characterized in that a wear layer is provided on both the inner surface of the TC outer jacket (81) and the outer surface of the TC inner jacket (82).
6. Drive shaft assembly for a screw drilling tool according to claim 1 or 2, characterized in that a positioning assembly is provided at the upper end of the thrust bearing set (3) for axially positioning the thrust bearing set (3) and the deep groove ball bearing set (4).
7. The drive shaft assembly for a screw drilling tool according to claim 6, wherein the positioning assembly comprises a positioning outer sleeve (91), a positioning inner sleeve (92), and a positioning nut (93) fixed on the spindle (1), The two ends of the positioning inner sleeve (92) respectively abut against the upper end faces of the positioning nut (93) and the inner ring of the thrust bearing group (3), the inner wall of the shell (2) is provided with a limiting step with the end face facing downwards, and the two ends of the positioning outer sleeve (91) respectively abut against the limiting step and the upper end face of the outer ring of the thrust bearing group (3).
8. The drive shaft assembly for a screw drilling tool according to claim 7, wherein the first floating spacer ring (51) is arranged between the positioning inner sleeve (92) and the housing, and the second floating spacer ring (52) is arranged between the positioning inner sleeve (92) and the positioning outer sleeve (91).
9. The drive shaft assembly for a screw drilling tool according to claim 1 or 8, wherein the first floating spacer ring (51) and the second floating spacer ring (52) are each made of polytetrafluoroethylene material.
10. The transmission shaft assembly for the screw drilling tool according to claim 1, wherein a first oil filling port (21) and a second oil filling port (22) are arranged on the shell (2), the first oil filling port (21) is communicated with the first lubrication cavity (6), and the second oil filling port (22) is communicated with the second lubrication cavity (7).

Description

Transmission shaft assembly for screw drilling tool Technical Field The invention belongs to the technical field of petroleum drilling tools, and particularly relates to a transmission shaft assembly for a screw drilling tool. Background The screw drilling tool mainly comprises a motor, a universal shaft and a transmission shaft assembly. The main function of the transmission shaft assembly is that under the conditions that the mandrel rotates and the shell is static, axial force such as weight on bit is transmitted through the thrust bearing, and the mandrel is stabilized through the TC radial bearing. In order to reduce the temperature and wear of thrust bearings and TC radial bearings, most drive shaft assemblies currently employ an open architecture that uses drilling fluid for cooling and lubrication. Because the drilling fluid contains a large amount of sand grains and other solids, the lubricating function of the drilling fluid is poor, so that the abrasion to the bearing is large, and the service life of the bearing is greatly reduced. The clearance between the inner sleeve and the outer sleeve of the TC shaft radial bearing is generally 0.15mm, the formed flow resistance can effectively limit the flow of drilling fluid, but the clearance causes the mandrel to have the activity of 0.15mm, so that the TC shaft has poor vibration inhibiting effect, and the fatigue damage of the mandrel is easy to cause. Chinese patent publication 201320693139.X discloses a sealed thrust bearing for a screw drill drive shaft, which specifically discloses a structure for sealing the bearing, but does not consider the seal pressure change caused by downhole high temperature and pressure change, and the seal structure is easily damaged by larger pressure, resulting in seal failure. The China patent literature 201110226400.0 discloses an oil seal screw drilling tool transmission shaft assembly with a pressure compensation function for petroleum and natural gas drilling, which comprises a piston cylinder body sealing device and a pressure compensation device, wherein the sealing pressure compensation is considered, but the compensation capability of a conical spring adopted by the pressure compensation device is very limited, the problems of fixation and fatigue damage of a mandrel are not considered, and the service life and the fatigue resistance of the mandrel of the screw drilling tool cannot be improved. Disclosure of Invention Aiming at the technical problems, the invention aims to provide the transmission shaft assembly for the screw drilling tool, which can obviously improve the service life and fatigue resistance of the transmission shaft of the screw drilling tool, is very beneficial to improving the overall service life of the screw drilling tool, improving the underground drilling footage and reducing the drilling cost. According to the invention, the transmission shaft assembly for the screw drilling tool comprises a mandrel, a shell sleeved on the mandrel, a thrust bearing group used for transmitting axial force, a deep groove ball bearing group used for inhibiting radial vibration of the mandrel, and a sealing assembly arranged between the mandrel and the shell, wherein the sealing assembly comprises a first floating isolation ring, a second floating isolation ring and a sealing element which are sequentially distributed at intervals from top to bottom, a first lubrication cavity and a second lubrication cavity are respectively formed among the first floating isolation ring, the second floating isolation ring and the sealing element in the axial direction and used for filling lubricating oil, the thrust bearing group and the deep groove ball bearing group are arranged in the second lubrication cavity, the deep groove ball bearing group is arranged at the lower end of the thrust bearing group, and the first floating isolation ring and the second floating isolation ring can move along the axial direction when the lubricating oil expands at high temperature, so that the lubricating oil in the second lubrication cavity can be isolated. In one embodiment, the outer race of the deep groove ball bearing set is in interference fit with the housing and the inner race of the deep groove ball bearing set is in interference fit with the spindle. In one embodiment, a TC radial bearing is arranged between the lower end of the shell and the mandrel, the TC radial bearing comprises a TC outer sleeve fixedly connected with the shell and a TC inner sleeve fixedly connected with the mandrel, The sealing element is disposed between the TC outer jacket and the TC inner jacket. In one embodiment, a gap is left between the radial directions of the TC outer sleeve and the TC inner sleeve, so that radial vibration of the mandrel is transmitted to the outer shell through the deep groove ball bearing group. In one embodiment, a wear layer is provided on both the inner surface of the TC outer jacket and the outer surface of the TC inner