Lead screw transmission mechanism with self-locking / anti-back function and downhole tool

Abstract

The utility model discloses a screw rod drive mechanism and downhole tool with self-locking / anti-retreating function, one end of the bearing is connected with the one end of nut towards the load direction, and the inner wall of bearing is equipped with the screw thread that cooperates with the outer screw thread of screw rod, and the other end of bearing is connected with load input part through spring, the utility model discloses a bearing, buffer mechanism are set up to the one end of nut towards the load direction, utilize the screw thread of screw rod to bear axial load while giving attention to transmission efficiency, can prevent the retreat of nut, possess self-locking capacity, through the screw thread, the ball is isolated with axial load, guarantees the safety of ball, can long -term normal use, improves life.

Description

Technical Field

[0001] This utility model relates to the fields of petroleum and downhole tools, specifically a screw drive mechanism and downhole tool with self-locking / anti-reverse function. Background Technology

[0002] Currently, commonly available lead screw-type power transmission mechanisms can be broadly categorized into two types: ball screws and trapezoidal screws. Ball screws offer high transmission efficiency but have a lower axial load capacity—the load acts directly on the balls and cannot prevent backing out; they automatically retract after being loaded. Trapezoidal screws, on the other hand, have lower transmission efficiency but a larger load capacity and possess some self-locking capability, though this self-locking ability is limited. In the field of oil well machinery, some tools utilize lead screw power transmission mechanisms, such as downhole electric shockers. During operation, the lead screw / screw experiences significant axial impact due to striking, requiring the ability to efficiently transmit power while also possessing self-locking anti-backing capabilities and the capacity to withstand large loads to ensure the tool functions properly and withstands various challenges. Summary of the Invention

[0003] This utility model aims to solve the existing problems by providing a lead screw transmission mechanism and downhole tool with self-locking / anti-reverse function.

[0004] To achieve the above objectives, the technical solution adopted by this utility model includes a screw and a nut. The outer wall and inner wall of the screw are respectively provided with a plurality of cavities for accommodating balls. It also includes a bearing member. One end of the bearing member is connected to the end of the nut facing the load direction. The inner wall of the bearing member is provided with threads that mate with the external threads of the screw. The other end of the bearing member is connected to a load input member through a spring.

[0005] The supporting component is cylindrical, with one end of its inner wall connected to a nut.

[0006] The other end of the bearing component has an annular groove. One end of the spring is fixed to the bottom of the annular groove, and the other end of the spring is connected to a load input component that can move axially.

[0007] This also includes pins, through which the spring is fixed to the load-bearing component.

[0008] The thread size of the bearing component is adapted to the external thread size of the screw.

[0009] The nut also has locking caps on the inner walls of both ends.

[0010] This utility model also provides a downhole tool, including any of the aforementioned lead screw transmission mechanisms with self-locking / anti-reverse function.

[0011] Compared with the prior art, this utility model sets a bearing member and a buffer mechanism at the end of the nut facing the load direction. While taking into account the transmission efficiency, it uses the thread of the screw to bear the axial load, which can prevent the nut from backing out and has self-locking ability. The screw threads isolate the ball from the axial load, ensuring the safety of the ball and allowing it to be used normally for a long time, thus improving its service life. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of an embodiment of the present utility model;

[0013] See attached diagram: 1. Screw; 2. Limit lock nut; 3. Front fixed lock cap; 4. Ball bearing cavity; 5. Rear fixed lock cap; 6. Bearing component; 7. Pin; 8. Spring; 9. Load input component. Detailed Implementation

[0014] The present invention will now be further described with reference to the accompanying drawings. See also: Figure 1 , Figure 1 This invention demonstrates an embodiment of a lead screw drive mechanism with self-locking / anti-reverse function, which can be used in downhole tools in the oil industry.

[0015] This embodiment includes a screw and a nut. The outer wall of the screw has external threads, and the inner wall of the nut has internal threads. The internal and external threads cooperate to form a lead screw transmission mechanism. The outer and inner walls of the screw also have several cavities (spherical) corresponding to accommodate balls, each containing a ball. When an external power drives the screw to rotate circumferentially around its axis, the screw drives the nut to move linearly along the axis through the threads and balls. Limiting lock nuts are also provided at both ends of the screw to limit the nut's travel.

[0016] See Figure 1 This embodiment also includes a support member, which is a cylindrical shape with both ends open. The inner wall of one end is fixedly connected to the outer wall of the nut by threads. The annular end face of the other end is provided with a recessed annular groove. One end of the spring is fixed to the bottom of the annular groove, and the other end of the spring is connected to an axially movable load input member. The load input member is a component that receives external axial load and transmits it to the nut. After receiving an axial load pointing towards the nut, the spring is compressed to absorb some of the energy.

[0017] The inner wall of the bearing component is provided with threads that mate with the external threads of the screw. The ends of the threads extend into the thread grooves of the external threads of the screw—this part can be considered as an additional trapezoidal nut section outside the ball nut. The width between the threads and the thread grooves should be appropriate to ensure that the threads and external threads maintain a locked axial relative position when the bearing component is subjected to axial loads. The groove walls prevent the bearing component and nut from retracting through elastic contact with the threads, and prevent the bearing component from transmitting residual axial load energy to the nut and balls, thus ensuring its safety and reliability.

[0018] Preferably, the spring is fixed to the load-bearing member by a pin; and the pin and the load-bearing member are preferably interference-fitted to improve structural strength.

[0019] Preferably, the inner walls at both ends of the nut are provided with front and rear locking caps to seal the space of the ball bearing cavity.

[0020] During assembly, first connect the front retaining cap to the inner wall of the nut via threads; then insert several ball bearings into the cavities within the nut's inner wall; finally, connect the rear retaining cap to the inner wall of the nut at the other end via threads to seal the ball bearings within each cavity. Next, thread the sealed nut onto the screw rod and connect a limit lock nut to one end of the screw rod via threads. Then, connect one end of the load-bearing component to the axial load-bearing end of the nut via threads, and connect the load input component with a spring to the axial load-bearing end of the load-bearing component, securing it with a guide pin via an interference fit. Finally, connect the other limit lock nut to the other end of the screw rod via threads.

[0021] In operation, power is transmitted to the screw via external power, causing the screw to rotate circumferentially. Simultaneously, the nut moves axially along the screw, and the load input component moves synchronously. If the power input is stopped, the screw stops rotating, and the nut stops at a specific position on the screw body.

[0022] At this point, the external axial load is transferred to the load input component. Due to the compression of the spring, the load input component will move towards the side of the bearing component, and the spring will absorb part of the load energy. The remaining energy of the external axial load is transferred to the screw rod (thread groove) through the threads of the bearing component, preventing the load from being transmitted to the balls. This isolates the balls from the axial load, ensuring the safety of the balls and allowing them to be used normally for a long time, thus improving the lifespan of the component. Simultaneously, the nut will not move backward due to the axial load, thus possessing self-locking capability.

[0023] This utility model also provides a downhole tool, including the lead screw transmission mechanism with self-locking / anti-reverse function of the aforementioned embodiment, which has the same solution and effect, so it will not be described in detail.

[0024] The embodiments of this utility model have been described above with reference to the accompanying drawings and examples. The structures given in the embodiments do not constitute a limitation on this utility model. Those skilled in the art can make adjustments as needed, and various modifications or variations within the scope of the appended claims are all within the scope of protection.

Claims

1. A lead screw transmission mechanism with self-locking / anti-reverse function, comprising a screw and a nut, wherein the outer wall and inner wall of the screw are respectively provided with a plurality of cavities for accommodating balls, characterized in that: It also includes a load-bearing component, one end of which is connected to the end of the nut facing the load direction, and the inner wall of the load-bearing component is provided with threads that mate with the external threads of the screw; the other end of the load-bearing component is connected to the load input component via a spring.

2. The lead screw transmission mechanism with self-locking / anti-reverse function according to claim 1, characterized in that: The support component is cylindrical, with one end of its inner wall connected to a nut.

3. The lead screw transmission mechanism with self-locking / anti-reverse function according to claim 1 or 2, characterized in that: The other end of the bearing component has an annular groove. One end of the spring is fixed to the bottom of the annular groove, and the other end of the spring is connected to a load input component that can move axially.

4. The lead screw transmission mechanism with self-locking / anti-reverse function according to claim 3, characterized in that: It also includes pins, by which the spring is fixed to the load-bearing component.

5. The lead screw transmission mechanism with self-locking / anti-reverse function according to claim 1 or 2, characterized in that: The thread size of the bearing component is adapted to the external thread size of the screw.

6. The lead screw transmission mechanism with self-locking / anti-reverse function according to claim 1, characterized in that: The inner walls at both ends of the nut are also equipped with locking caps.

7. A downhole tool, characterized in that: Including the lead screw drive mechanism with self-locking / anti-reverse function as described in any one of claims 1-6.

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