Axial locking mechanism

Abstract

The invention relates to an axial locking mechanism which comprises a locking structure assembled between a shaft sleeve (1) and a shaft (2). The locking structure comprises a locking piece, a locking groove (11) and a shaft sleeve locking shoulder (12) are arranged on the shaft sleeve (1), and the shaft sleeve locking shoulder (12) is the lower limit of the shaft (2). The shaft (2) is provided with a boss (21), and the boss (21) is provided with an accommodating groove (22); when the shaft (2) moves to the lower limit relative to the shaft sleeve (1), the accommodating groove (22) is jointed with the locking groove (11), and the locking piece is combined with the accommodating groove (22) and the locking groove (11) to form an upper limit of the shaft (2); the problem that the pump starting state is required to be kept all the time in the drilling process so as to avoid locking failure after the pump is stopped due to the fact that existing axial locking performs upper limiting and lower limiting through the acting force generated by the pump pressure on the shaft is effectively solved.

Description

Technical Field

[0001] The present disclosure relates to the technical field of oil and gas drilling, and in particular to an axial locking mechanism. Background Art

[0002] As oil and gas field development deepens, the exploration and development of deep and ultra-deep wells, as well as unconventional oil and gas resources such as shale oil and tight oil, places increasingly stringent demands on drilling processes and tools. This has led to the emergence of a variety of new drilling and completion tools, some of which require axial locking of the shaft and sleeve during transitional or final operation.

[0003] In existing drilling and completion tools, the axial locking method typically uses pump pressure to set the upper limit on the shaft force and a shoulder on the sleeve to set the lower limit, thereby achieving axial locking of the shaft relative to the sleeve. This method relies on pump pressure, which cannot be maintained continuously during drilling. Therefore, this method loses its locking effect after the pump is stopped. Summary of the Invention

[0004] In view of this, the present disclosure provides an axial locking mechanism to solve the problem that the existing axial locking method uses the force generated by the pump pressure on the shaft to set the upper limit and the shoulder on the sleeve to set the lower limit, so it needs to rely on pump pressure and requires that the pump be kept on at all times during drilling to avoid the problem of locking failure after the pump is stopped.

[0005] To achieve the above-mentioned object of the invention, the axial locking mechanism includes: A locking structure assembled between the sleeve and the shaft; The locking structure includes a locking member, and a locking groove and a sleeve locking shoulder are configured on the sleeve, and the sleeve locking shoulder is the lower limit of the shaft; a boss is configured on the shaft, and a receiving groove is configured on the boss, and the locking structure is placed in the receiving groove; When the shaft moves relative to the shaft sleeve to the lower limit position, the receiving groove engages with the locking groove, and the locking member combines with the receiving groove and the locking groove to form the upper limit position of the shaft.

[0006] In the present disclosure and possible embodiments, the locking member is a locking ball; One end surface of the locking groove is the shaft sleeve locking end surface; An anti-slip end surface and a shaft locking end surface are configured on one end surface of the receiving groove, and the locking ball is installed in the receiving groove; When the shaft is at the lower limit position, the distance between the anti-slip end surface and the locking end surface of the sleeve is greater than the diameter of the locking ball, and the locking ball enters the locking groove; if the shaft moves upward, the shaft locking end surface is limited by the locking ball and the locking end surface of the sleeve, and at this time the distance between the anti-slip end surface and the locking end surface of the sleeve is less than the diameter of the locking ball, and the locking ball is in a completely locked state.

[0007] In the present disclosure and possible embodiments, the number of the receiving grooves is at least , the number of the locking balls corresponds to the number of the receiving grooves, and a corresponding number of locking balls are circumferentially distributed and assembled in the receiving grooves.

[0008] In the present disclosure and possible embodiments, a compression spring is connected to the bottom of the receiving groove, and the locking ball is assembled in the receiving groove via the compression spring; When the receiving groove is engaged with the locking groove, the compression spring releases its elasticity to assist the locking ball in entering the locking groove.

[0009] In the present disclosure and possible embodiments, the locking member is an elastic plug compressed and fixed in the receiving groove; When the shaft moves relative to the sleeve to the lower limit position, the receiving groove engages with the locking groove, and the elastic plug that releases the compression elasticity is inserted into the locking groove. The elastic plug, the locking groove and the receiving groove cooperate to form the upper limit position of the shaft.

[0010] The present disclosure has the following beneficial effects: The axial locking mechanism disclosed herein comprises a locking piece assembled between the sleeve and the shaft, a locking groove being configured on the sleeve, a boss being configured on the shaft, and a receiving groove being configured on the boss, and the locking piece being placed in the receiving groove; when the receiving groove engages with the locking groove, the locking piece realizes locking between the sleeve and the shaft with the cooperation of the receiving groove and the locking groove; therefore, the axial locking mechanism disclosed herein does not need to rely on pump pressure for locking when the shaft needs to be axially locked relative to the sleeve, so there is no need to keep the pump in the on state during drilling to maintain the pump pressure, and the problem of locking failure after stopping the pump will not occur. In short, the axial locking mechanism of the present invention provides a strong guarantee for the safe and effective operation of downhole drilling and completion tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings herein are incorporated into and constitute a part of the specification. These drawings illustrate embodiments consistent with the present disclosure and, together with the specification, are used to explain the technical solutions of the present disclosure.

[0012] Figure 1 This is a schematic structural diagram of the axial locking mechanism in an unlocked state according to an embodiment of the present disclosure; Figure 2is a schematic structural diagram of a shaft sleeve according to an embodiment of the present disclosure; Figure 3 is a schematic structural diagram of a locking groove according to an embodiment of the present disclosure; Figure 4 is a schematic structural diagram of the shaft according to an embodiment of the present disclosure; Figure 5 This is a schematic structural diagram of a receiving tank according to an embodiment of the present disclosure; Figure 6 This is a schematic structural diagram of the axial locking mechanism in a locked state according to an embodiment of the present disclosure; Figure 7 It is a schematic diagram of the partial structure of the locking groove when the axial locking mechanism of the embodiment of the present disclosure is locked. DETAILED DESCRIPTION

[0013] The present disclosure is described below based on embodiments, but it is worth noting that the present disclosure is not limited to these embodiments. In the detailed description of the present disclosure below, some specific details are described in detail. However, for the parts not described in detail, those skilled in the art can also fully understand the present disclosure.

[0014] In addition, those skilled in the art should understand that the drawings provided are only for the purpose of illustrating the purpose, features and advantages of the present disclosure and are not drawn to scale. In the description of this application, it should be understood that the terms "upper", "lower", "front", "back", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the drawings and are only for the convenience of describing this application and simplifying the description. They do not indicate or imply that the devices or components referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, they should not be understood as limiting this application.

[0015] At the same time, unless the context clearly requires otherwise, words such as "include", "comprising" and the like throughout the specification and claims should be interpreted as inclusive rather than exclusive or exhaustive; that is, as "including but not limited to".

[0016] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0017] The technical concept of the axial locking mechanism disclosed in the present invention is to assemble a locking structure between the sleeve 1 and the shaft 2, which includes a locking member, and a locking groove 11 and a sleeve locking shoulder 12 are arranged on the sleeve 1, and the sleeve locking shoulder 12 serves as the lower limit of the shaft 2; at the same time, a boss 21 is arranged on the shaft 2, and a receiving groove 22 is arranged on the boss 21, and then the locking structure is placed in the receiving groove 22; when the shaft 2 moves to the lower limit relative to the sleeve 1, the receiving groove 22 engages with the locking groove 11, and the locking member combines with the receiving groove 22 and the locking groove 11 to form the upper limit of the shaft 2.

[0018] Based on the above inventive concept, the embodiment of the present disclosure provides a specific axial locking mechanism. Figure 1 is a schematic structural diagram of the axial locking mechanism in an unlocked state according to an embodiment of the present disclosure; Figure 1 As shown, the locking element of the axial locking mechanism is a locking ball 3 , which is mounted on the shaft 2 , and the shaft 2 is mounted on the sleeve 1 .

[0019] Figure 2 is a schematic structural diagram of the shaft sleeve according to an embodiment of the present disclosure; Figure 2 As shown, the shaft sleeve 1 is provided with a locking groove 11 and a shaft sleeve locking shoulder 12; Figure 3 is a schematic structural diagram of the locking groove of the embodiment of the present disclosure; Figure 3 As shown, one side end surface of the locking groove 11 is a shaft sleeve locking end surface 111 .

[0020] Figure 4 is a schematic structural diagram of the shaft according to an embodiment of the present disclosure; Figure 4 In the embodiment, the shaft 2 is provided with a boss 21, and a receiving groove 22 is provided on the boss. The receiving groove 22 is a ball groove, and one end surface of the boss is a shaft locking shoulder 23. Preferably, there are multiple receiving grooves 22, which are evenly distributed around the circumference of the boss 21. Figure 5 is a schematic structural diagram of the receiving tank according to an embodiment of the present disclosure; Figure 5 In the embodiment, one end face of the receiving groove 22 is provided with an anti-slip end face 221 and a shaft locking end face 222 .

[0021] During assembly, a corresponding number of locking balls 3 are circumferentially distributed and installed within the receiving grooves 22, corresponding to the number of receiving grooves 22 on the boss. After installation, the outer diameter of the radial cross-section of the locking balls 3 is no larger than the outer diameter of the boss 21. After assembly, before the axial locking mechanism is engaged, the shaft 2 can move axially relative to the sleeve 1; after engagement, the shaft 2 cannot move axially relative to the sleeve 1.

[0022] Furthermore, the locking principle and locking process of the axial locking mechanism of this embodiment are specifically and detailedly described with reference to the accompanying drawings. The specific process is as follows: When the shaft 2 is not required to be axially locked relative to the sleeve 1, the axial locking mechanism is in Figure 1 In the state shown, the shaft 2 can move axially relative to the shaft sleeve 1 and can also perform unobstructed rotational movement relative to the shaft sleeve 1.

[0023] When the shaft 2 needs to be axially locked relative to the sleeve 1, the shaft 2 is moved axially relative to the sleeve 1 until the shaft locking shoulder 23 contacts the sleeve locking shoulder 12, the locking groove 11 engages with the receiving groove 22, and the distance between the anti-slip end face 221 and the sleeve locking end face 111 is greater than the diameter of the locking ball 3, so the locking ball 3 will fall into the locking groove 11 under the action of gravity, that is, Figure 6 Status shown.

[0024] exist Figure 6 In the state shown, if the shaft 2 continues to move downward, it will be limited by the shaft sleeve locking shoulder 12. If the shaft 2 moves upward, the shaft locking end face 222 will be limited by the locking ball 3 and the shaft sleeve locking end face 111. At this time, the distance between the anti-slip end face 221 and the shaft sleeve locking end face 111 is less than the diameter of the locking ball 3. At this time, the locking ball 3 is in a completely locked state. Figure 7 As shown; obviously, in Figure 7 In the state shown, the locking ball 3 , the sleeve locking end surface 111 of the locking groove 11 , the anti-slip end surface 221 of the receiving groove 22 , and the shaft locking end surface 222 work together to form the upper limit position of the shaft 2 .

[0025] It is understood that when the relative movement between the shaft 2 and the sleeve 1 is in the vertical direction, the locking ball 3 will naturally fall into the locking groove 11 due to the action of gravity. However, if the relative movement between the shaft 2 and the sleeve 1 is in the horizontal direction, the locking ball 3 will not naturally fall into the locking groove 11. To solve this problem, the present embodiment is designed to dispose an elastic member below the locking ball 3, and fix the elastic member to the bottom of the locking groove 11. The locking ball 3 compresses the elastic member and is assembled in the locking groove 11, and then assembled with the sleeve 1. In this way, when the shaft 2 moves axially relative to the sleeve 1 to the shaft locking shoulder 23 and contacts the sleeve locking shoulder 12, the locking groove 11 and the receiving groove 22 engage as above, and the compressed elasticity of the elastic member is released. With the help of this compressed elasticity, the locking ball 3 is driven into the locking groove 11. Of course, the elastic member can be a commonly used compression spring, or other elastic members with the same function, and the present disclosure is not limited to this.

[0026] In addition, based on the above-mentioned inventive concept, the axial locking structure of the embodiment of the present disclosure further provides a second locking structure design, which is as follows: Because the structure of the second locking structure is relatively simple, the corresponding structural diagram is no longer provided in this embodiment. For the second locking structure, the locking member is an elastic plug. The elastic plug can adopt a commonly used plug bottom fixing spring structure, and then the spring is fixed in the receiving groove 22. During assembly, the elastic plug is assembled as a whole in the receiving groove 22 with the spring in a compressed state. When the shaft 2 moves to the lower limit relative to the sleeve 1, the locking groove 11 engages with the receiving groove 22, and the elasticity of the compressed spring is released. The elastic plug pops out of the receiving groove and inserts into the locking groove 11, thereby limiting the axial movement of the shaft 2 relative to the sleeve 1. At this time, the elastic plug, the locking groove 11, and the receiving groove 22 together serve as the upper limit of the shaft 2, achieving the purpose of axial locking of the shaft 2. Of course, in order to ensure the effect of axial locking, the spring is preferably made of a hard material.

[0027] As can be seen from the above description, the axial locking mechanism of this embodiment eliminates the need to rely on pump pressure to achieve axial locking of shaft 2 relative to sleeve 1. Furthermore, there is no need to maintain the pump on during drilling to maintain pressure, and the issue of locking failure after pumping is eliminated. Therefore, the axial locking mechanism of the present invention effectively ensures the safe and efficient operation of downhole drilling and completion tools.

[0028] The above-described embodiments are merely examples of implementation methods of the present disclosure, and their descriptions are relatively specific and detailed. However, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art may make various modifications, equivalent substitutions, and improvements without departing from the scope of the present disclosure, and these modifications are all within the scope of protection of the present disclosure. Therefore, the scope of protection of the present invention shall be based on the appended claims.

Claims

1. An axial locking mechanism, characterized in that: include: A locking structure assembled between the sleeve (1) and the shaft (2); The locking structure includes a locking member, and a locking groove (11) and a sleeve locking shoulder (12) are configured on the sleeve (1), and the sleeve locking shoulder (12) is the lower limit of the shaft (2); a boss (21) is configured on the shaft (2), and a receiving groove (22) is configured on the boss (21), and the locking structure is placed in the receiving groove (22); When the shaft (2) moves relative to the shaft sleeve (1) to the lower limit position, the receiving groove (22) engages with the locking groove (11), and the locking member combines with the receiving groove (22) and the locking groove (11) to form the upper limit position of the shaft (2).

2. The axial locking mechanism according to claim 1, characterized in that: The locking member is a locking ball (3); In the locking structure, one end face of the locking groove (11) is a shaft sleeve locking end face (111); one end face of the receiving groove (22) is provided with an anti-slip end face (221) and a shaft locking end face (222); the locking ball (3) is installed in the receiving groove (22); When the shaft (2) is at the lower limit position, the distance between the anti-slip end surface (221) and the shaft sleeve locking end surface (111) is greater than the diameter of the locking ball (3), and the locking ball (3) enters the locking groove (11); if the shaft (2) moves upward, the shaft locking end surface (222) is limited by the locking ball (3) and the shaft sleeve locking end surface (111), and at this time, the distance between the anti-slip end surface (221) and the shaft sleeve locking end surface (111) is less than the diameter of the locking ball (3), and the locking ball (3) is in a completely locked state.

3. The axial locking mechanism according to claim 2, characterized in that: The number of the receiving grooves (22) is at least one, the number of the locking balls (3) corresponds to the number of the receiving grooves (22), and a corresponding number of locking balls 3 are circumferentially distributed and assembled in the receiving grooves (22).

4. The axial locking mechanism according to claim 2 or 3, characterized in that: The bottom of the receiving groove (22) is connected to a compression spring, and the locking ball (3) is assembled in the receiving groove (22) through the compression spring; When the receiving groove (22) is engaged with the locking groove (11), the compression spring releases its elasticity to assist the locking ball (3) in entering the locking groove (11).

5. The axial locking mechanism according to claim 1, characterized in that: The locking member is an elastic plug compressed and fixed in the receiving groove (22); When the shaft (2) moves relative to the shaft sleeve (1) to the lower limit position, the receiving groove (22) engages with the locking groove (11), and the elastic plug that releases the compression elasticity is inserted into the locking groove (11). The elastic plug, the locking groove (11) and the receiving groove (22) cooperate to form the upper limit position of the shaft (2).

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