High-speed transmission shaft assembly

Abstract

The utility model belongs to the technical field of screw drilling tools, and particularly relates to a high-speed transmission shaft assembly which comprises a transmission shaft, a transmission shaft sleeve and a transmission shaft sleeve. The upper TC bearing static sleeve is in interference fit with the transmission shaft; the lower TC bearing static sleeve is in clearance fit with the transmission shaft; the sealing oil injection device comprises a sealing piston located at the upper end of the transmission shaft and a U-shaped sealing ring; the V-shaped sealing ring, the spring and the pressurizing ring are positioned at the lower end of the transmission shaft; lubricating agents are injected into the transmission shaft assembly. According to the utility model, the reliability and the service life of the screw drill are obviously improved and prolonged through structural innovation. Firstly, a traditional upper TC bearing movable sleeve is omitted, a wear-resistant alloy layer is overlaid on the surface of the transmission shaft, the number of kinematic pairs is reduced, the failure problem caused by abrasion of the movable sleeve is avoided, and meanwhile the manufacturing cost is reduced.

Description

Technical Field

[0001] This utility model belongs to the field of screw drill technology, specifically relating to a high-speed transmission shaft assembly. Background Technology

[0002] In oil drilling engineering, the screw drill string is a core power device, and the performance of its drive shaft assembly directly affects drilling efficiency and cost. Traditional drive shaft assemblies use an open mud lubrication structure, which has significant drawbacks under high-speed conditions: insufficient stability of mud lubrication leads to accelerated wear of bearings and drive shafts. The double-sleeve structure of the upper TC bearing's moving and stationary sleeves not only increases manufacturing costs but also causes localized overheating and wear due to dynamic fit issues during high-speed rotation, becoming a weak link in system reliability.

[0003] Furthermore, existing sealing systems are ill-equipped to withstand the intrusion of high-pressure drilling mud, and the drive shaft surface lacks wear-resistant reinforcement treatment, leading to frequent media leakage and surface wear grooves. This further shortens drill string life and increases the risk of downhole accidents. These technical bottlenecks restrict the application of high-speed drilling technology in complex formations, necessitating improvements in the reliability and wear resistance of the drive shaft assembly through structural optimization and integrated sealing and lubrication systems to meet the demands of high-efficiency drilling. Utility Model Content

[0004] The purpose of this invention is to provide a high-speed drive shaft assembly to solve the problems existing in the prior art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a high-speed drive shaft assembly, comprising:

[0006] The drive shaft has a wear-resistant alloy layer on its surface;

[0007] The upper TC bearing stationary sleeve is interference-fitted with the drive shaft;

[0008] The lower TC bearing stationary sleeve is clearance-fitted with the drive shaft.

[0009] The sealing oil injection device includes:

[0010] A sealing piston and a "U"-shaped sealing ring located at the upper end of the drive shaft;

[0011] The "V"-shaped seal, spring, and pressure ring are located at the lower end of the drive shaft;

[0012] Lubricant is injected into the drive shaft assembly.

[0013] Preferably, the sealing oil injection device further includes an O-ring seal between the upper housing and the sealing piston;

[0014] The O-ring seal between the lower locking mold and the "V"-shaped sealing ring.

[0015] Preferably, the wear-resistant alloy layer is a tungsten carbide alloy material, which is fixed to the outer surface of the drive shaft by a welding process.

[0016] Preferably, the inner surface of the upper TC bearing stationary sleeve is provided with a spiral oil groove, forming a labyrinth seal structure with the surface of the drive shaft.

[0017] Preferably, the opening direction of the "V"-shaped sealing ring is consistent with the direction of the spring force, and the pressure ring is disposed between the spring and the "V"-shaped sealing ring.

[0018] Preferably, the sealing piston is provided with an annular boss, and the "U"-shaped sealing ring is fitted on the outside of the annular boss to form a dynamic seal with the inner surface of the upper housing.

[0019] The beneficial effects of this utility model are as follows: This utility model significantly improves the reliability and service life of screw drills through structural innovation. First, by eliminating the traditional TC bearing moving sleeve and welding a wear-resistant alloy layer onto the surface of the drive shaft, the number of moving pairs is reduced, avoiding failure problems caused by wear of the moving sleeve, and simultaneously reducing manufacturing costs. The sealing and oiling device adopts a multi-stage sealing structure at both ends: the upper piston, in conjunction with a "U"-shaped sealing ring, forms a dynamic seal, while the lower "V"-shaped sealing ring, spring, and pressure-increasing ring combine to form a pressure-compensating seal. Combined with the internally injected lubricant, it effectively isolates mud erosion and forms a stable lubrication environment, enabling the drive shaft assembly to maintain low frictional loss during high-speed rotation, increasing its service life by more than 30%.

[0020] Secondly, the optimized sealing system and structural design achieve high-efficiency transmission performance. The spiral oil grooves of the upper TC bearing stationary sleeve form a labyrinth seal with the drive shaft surface, enhancing the retention capacity of the lubricating medium; the clearance fit design of the lower TC bearing stationary sleeve allows for slight axial displacement, compensating for thermal expansion and reducing assembly stress. This fully sealed closed-loop lubrication structure enables the drive shaft assembly to adapt to high-speed operating conditions of 300-500 rpm, increasing the mechanical drilling rate by 15-20%, while reducing the risk of mud contamination and lowering the probability of downhole tool failure, making it particularly suitable for high-efficiency drilling operations in complex formations. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of this utility model. Detailed Implementation

[0022] The specific embodiments of this utility model are described in detail below with reference to the accompanying drawings and preferred embodiments.

[0023] like Figure 1As shown, the upper housing 1, serving as the top pressure-bearing component, is forged from 35CrMo alloy steel, with trapezoidal threads machined on its inner surface for installing the plug 3. The sealing piston 2 has a cylindrical structure with an annular boss machined on its outer cylindrical surface. A U-shaped sealing ring B3 is fitted on the outside of the boss, forming a dynamic seal with the inner surface of the upper housing 1. The plug 3 is fixed to the top of the upper housing 1 via a threaded connection, serving as a grease injection port. The inner surface of the upper TC bearing stationary sleeve 4 is machined with an oil groove with a helix angle of 30°, and it is interference-fitted with the upper end of the drive shaft 15 (H7 / k6 tolerance). The drive shaft 15 has a 0.8mm thick tungsten carbide alloy layer welded onto its surface, with the upper end interference-fitted with the upper TC bearing stationary sleeve 4 and the lower end clearance-fitted with the lower TC bearing stationary sleeve 10 (0.03-0.05mm). The tandem bearing 5 consists of two sets of single-row tapered roller bearings, installed back-to-back between the upper TC bearing stationary sleeve 4 and the spacer 7. The housing 6 serves as the main support structure, and its internal components are axially positioned with the pressure sleeve 8 via the spacer 7. The pressure-bearing sleeve 8 is fitted in the middle of the drive shaft 15 to bear the drilling pressure transmission. The semi-ring 9 is embedded in the inner wall of the housing 6. An annular groove restricts the axial displacement of the lower TC bearing stationary sleeve 10. The inner hole of the lower TC bearing stationary sleeve 10 is clearance-fitted with the drive shaft 15, and its outer circle is axially positioned with the lower locking mold 11 via the adjusting shim 12. The lower locking mold 11 is connected to the housing 6 by bolts, and its bottom surface contacts the spring 13. The adjusting shim 12 is a 0.1-0.3mm copper alloy sheet. The spring 13 has a pre-compression of 5-8mm, providing axial elasticity to the "V"-shaped seal ring B4. The "V"-shaped seal ring B4 has a lip angle of 45°, with the opening facing the lower end of the drive shaft 15. An "O"-shaped seal ring B1 is installed in the annular groove between the upper housing 1 and the sealing piston 2. An "O"-shaped seal ring B2 is installed in the annular groove between the lower locking mold 11 and the housing 6. The spiral oil groove on the inner surface of the upper TC bearing stationary sleeve 4 forms a labyrinth seal with the surface of the drive shaft 15. The upper TC bearing stationary sleeve 4 and the lower TC bearing stationary sleeve 10 are surface hardened to HRC58-62. The weld overlay of the drive shaft 15 is changed to a 1.2mm thick chromium-nickel carbide alloy. A triangular guide groove is added to the lip of the "U"-shaped seal ring B3. The spring 13 adopts a variable diameter design, with the smaller diameter end contacting the "V"-shaped seal ring B4. The adjusting shim 12 is changed to 0.2mm stainless steel with a molybdenum disulfide coating.

[0024] When the drive shaft 15 rotates at high speed, the spiral oil groove of the upper TC bearing stationary sleeve 4 pumps lubricant to the contact surface, forming a dynamic pressure oil film. Under the action of the spring 13 and the pressure ring 12, the lower "V"-shaped seal ring B4 dynamically compensates for the changes in sealing clearance caused by the axial reciprocating motion. The closed lubrication system completely isolates the mud, and the internal pressure is maintained stable through the dynamic seal between the piston 2 and the upper housing 1, achieving long-term reliable operation at speeds of 300-500 rpm.

[0025] It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

Claims

1. A high-speed drive shaft assembly, characterized in that, include: The drive shaft (15) has a wear-resistant alloy layer on its surface; The upper TC bearing stationary sleeve (4) is interference-fitted with the drive shaft (15); The lower TC bearing stationary sleeve (10) is clearance-fitted with the drive shaft (15); The tandem bearing (5) consists of two sets of single-row tapered roller bearings, mounted back-to-back between the upper TC bearing stationary sleeve (4) and the spacer (7). The sealing oil injection device includes: The sealing piston (2) and the "U"-shaped sealing ring (B3) are located at the upper end of the drive shaft (15); The "V"-shaped sealing ring (B4), spring (13) and pressure ring (12) are located at the lower end of the drive shaft (15); Lubricant is injected into the drive shaft assembly.

2. The high-speed drive shaft assembly according to claim 1, characterized in that, The sealing and oiling device further includes: an "O" ring (B1) between the upper housing (1) and the sealing piston (2); and an "O" ring (B2) between the lower locking mold (11) and the "V" ring (B4).

3. The high-speed drive shaft assembly according to claim 1, characterized in that, The wear-resistant alloy layer is made of tungsten carbide alloy material and is fixed to the outer surface of the drive shaft (15) by a welding process.

4. The high-speed drive shaft assembly according to claim 1, characterized in that, The inner surface of the upper TC bearing stationary sleeve (4) is provided with a spiral oil groove, which forms a labyrinth seal structure with the surface of the transmission shaft (15).

5. The high-speed drive shaft assembly according to claim 1, characterized in that, The opening direction of the "V"-shaped sealing ring (B4) is consistent with the elastic force direction of the spring (13), and the pressure ring (12) is disposed between the spring (13) and the "V"-shaped sealing ring (B4).

6. The high-speed drive shaft assembly according to claim 1, characterized in that, The sealing piston (2) is provided with an annular boss, and the "U"-shaped sealing ring (B3) is fitted on the outside of the annular boss to form a dynamic seal with the inner surface of the upper housing (1).

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