Low-speed pump hydraulic system driving equipment suitable for underground environment

Abstract

The low-speed pump hydraulic system driving equipment suitable for the underground environment comprises a first motor, a cam A, a cam B, a cam C, a plunger pump A, a first one-way valve, a hydraulic cylinder right chamber, a hydraulic cylinder left chamber and a first dynamic seal and support and is connected with a transmission shaft. The direct-current brush motor rotates forwards and backwards to control the double-plunger pump, a motor speed reducer and the like are arranged in a normal-pressure cavity, oil immersion is not needed, the cost is reduced, and the long-term working reliability of the motor is improved; a simple one-way valve combination is adopted in cooperation with a double-plunger pump, bidirectional movement of a balanced type oil cylinder piston rod executing element is achieved, application of a high-power and low-reliability hydraulic reversing valve in the complex underground environment is avoided, and the overall cost is effectively controlled. A low-speed and low-starting-current direct-current brush motor reducer combination and a controllable reversing scheme are adopted, the power requirement of an underground system is effectively lowered, and reliable communication and driving of deep well and ultra-deep well multistage underground intelligent tools are reliably achieved.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic drive technology for downhole intelligent tools, and in particular to a low-speed pump hydraulic system drive device suitable for downhole environments, and is suitable for precise motion control in confined spaces such as petroleum logging instruments and intelligent drilling tools. Background Art

[0002] To improve power density and driving force, existing downhole intelligent tools often employ hydraulic drive solutions. These solutions utilize an oil-immersed, high-speed brushless motor coupled with a low-displacement, high-pressure plunger pump as the hydraulic source. A valve control system employs a three-position, four-way directional valve to achieve cylinder reversal, addressing the bidirectional motion of the actuator. This solution suffers from the following significant drawbacks: ① The micro-directional valve is prone to internal leakage under high-pressure (>35MPa) conditions, resulting in reduced cylinder positioning accuracy; ② The valve core assembly requires extremely high oil cleanliness and is prone to sticking and failure in the harsh downhole conditions of high temperatures (>125°C) and impurities; ③ The electromagnetic engagement principle allows for sudden power surges during startup and reversal, which can easily cause electrical system malfunctions; ④ The large number of hydraulic components results in high overall cost; and ⑤ The high-speed motor is entirely oil-immersed, resulting in high power consumption at startup, posing significant quality and reliability risks. Summary of the Invention

[0003] The purpose of the present invention is to provide a low-speed pump hydraulic system drive device suitable for underground environment, so as to solve the problems of low underground working reliability and high cost in the existing technology, and to overcome the shortcomings of the current technology.

[0004] The technical solution of the present invention is: a low-speed pump hydraulic system driving device suitable for underground environment, including a first motor, cam A, cam B, cam C, plunger pump A, and a first one-way valve, a right chamber of a hydraulic cylinder, and a left chamber of a hydraulic cylinder. The first motor main shaft is equipped with a first dynamic seal and a support, and is connected to a transmission shaft, and the transmission shaft is respectively equipped with cam A and cam C, wherein,

[0005] The connection between the cam A and the transmission shaft adopts positive meshing and is respectively equipped with a screw sleeve, a transmission pin and a spring;

[0006] The connection between the cam C and the transmission shaft is connected by reverse meshing and is respectively provided with a screw sleeve, a transmission pin and a spring.

[0007] Furthermore, the main liquid outlet formed by the plunger pump A is connected to a first one-way valve, and the first one-way valve is interconnected with the right chamber of the hydraulic cylinder.

[0008] Furthermore, the branch liquid outlet formed by the plunger pump A is also connected to a second one-way valve, and the second one-way valve is connected to the oil tank.

[0009] Furthermore, the main liquid outlet formed by the plunger pump B is connected to a fourth one-way valve, and the fourth one-way valve is interconnected with the left chamber of the hydraulic cylinder.

[0010] Furthermore, the branch formed by the plunger pump B is connected to a third one-way valve, and the third one-way valve is connected to the oil tank.

[0011] Furthermore, it also includes a second motor, a second dynamic seal and a support are installed on the main shaft of the second motor, and the main shaft is connected to a cam B to drive the rotation of the cam B.

[0012] Furthermore, the first motor is arranged inside the downhole tool and is composed of a DC brush motor and a reducer.

[0013] Compared with the existing technology, the present invention has the following advantages: a DC brush motor is used to control the dual-plunger pump in both forward and reverse directions. The motor reducer and other components are placed in a normal pressure chamber, eliminating the need for oil immersion, which reduces costs and improves the long-term working reliability of the motor. A relatively simple one-way valve combination, combined with the use of a dual-plunger pump, achieves bidirectional movement of the balanced oil cylinder piston rod actuator, avoiding the use of high-power, low-reliability hydraulic reversing valves in complex downhole environments, effectively controlling overall costs. A low-speed, low-starting current DC brush motor reducer combination and a controllable reversing solution effectively reduce the power requirements of the downhole system, enabling reliable communication and drive of multi-stage downhole intelligent tools in deep and ultra-deep wells. The hydraulic drive structure has a wide range of applications and is suitable for micro bidirectional hydraulic systems of downhole intelligent tools, as well as for hydraulic drive structures of other downhole instruments and tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic diagram of the working principle of the present invention;

[0015] Figure 2 It is a schematic diagram of the structure of the present invention;

[0016] Figure 3 for Figure 2 Cross-sectional view along the middle line "AA";

[0017] Figure 4 for Figure 2 Cross-sectional view along the middle line "BB";

[0018] Figure 5 It is a structural schematic diagram of the present invention. DETAILED DESCRIPTION

[0019] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0020] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0021] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0022] See Figure 1-5 In the present invention, a low-speed pump hydraulic system driving device suitable for downhole environment includes a first motor 1, a cam A3, a cam B8, a cam C16, a plunger pump A4, a first one-way valve 5, a hydraulic cylinder right chamber 11, and a hydraulic cylinder left chamber 12. The first motor 1 is composed of a DC brush motor and a reducer, and is placed inside the downhole intelligent tool. A first dynamic seal and a support 2 are installed on the main shaft of the first motor 1 to reduce the rotational friction resistance generated by the external high pressure and acting on the main shaft of the first motor 1, and is connected to a transmission shaft 17. The cam A3 and the cam C16 are respectively installed on the transmission shaft 17, wherein the connection between the cam A3 and the transmission shaft 17 adopts a forward meshing connection, and is respectively installed with a screw sleeve 18, a transmission pin 19 and a spring 20; the connection between the cam C16 and the transmission shaft 17 adopts a reverse meshing connection, and is respectively installed with a screw sleeve 18, a transmission pin 19 and a spring 20; refer to FIG. Figure 3 AA is in clockwise direction. When the main shaft of the first motor 1 rotates in the positive direction, the surface of the transmission shaft 17 pushes the transmission pin 19 and drives the cam A3 to engage in the positive direction. The cam A3 rotates accordingly. Figure 4 The profile of the transmission shaft 17 in the BB cannot engage with the transmission pin 19, and the cam C16 slips and cannot rotate. Figure 3Similarly, in AA, when the main shaft of the first motor 1 rotates in the reverse direction, the positive meshing device of cam A3 slips and does not rotate, while the negative meshing device of cam C16 transmits torque and rotates accordingly. By controlling the positive and negative rotation of the first motor 1, the plunger pumps A4 and B15 are controlled respectively.

[0023] Specifically, the main liquid outlet formed by the plunger pump A4 is connected to the first one-way valve 5, and the first one-way valve 5 is interconnected with the right chamber 12 of the hydraulic cylinder. The branch liquid outlet formed is also connected to the second one-way valve 9, and the second one-way valve 9 is connected to the oil tank 22.

[0024] Specifically, the main liquid outlet formed by the plunger pump B15 is connected to the fourth one-way valve 14, the fourth one-way valve 14 is interconnected with the left chamber 12 of the hydraulic cylinder, and the formed branch is connected to the third one-way valve 13, and the third one-way valve 13 is connected to the oil tank 22.

[0025] Specifically, it also includes a second motor 6, which is used to reduce the rotational friction resistance generated by the external high pressure and acting on the main shaft of the second motor 6. A second dynamic seal and support 7 are installed on the main shaft of the second motor 6, and the main shaft is connected to a cam B8 to drive the rotation of the cam B8. ① When the high point of the cam B8 squeezes the valve core 24 of the third one-way valve 13, the third one-way valve 13 is in an open state, and the oil circuit of the left chamber 12 of the hydraulic cylinder is connected to the oil tank; at the same time, the low point of the cam B8 is disengaged from the valve core 23 of the second one-way valve 9, and the second one-way valve 9 is in a closed state; when the main shaft of the first motor rotates forward, the plunger pump A4 starts, and the high-pressure oil enters the right chamber 11 of the hydraulic cylinder. At the same time, the third one-way valve 13 is controlled to open, and the low-pressure oil in the left chamber 12 of the hydraulic cylinder flows back to the oil tank, and the piston rod 10 moves to the left; ② When the high point of the cam B8 squeezes the valve core 24 of the third one-way valve 13, the third one-way valve 13 is in an open state, and the oil circuit of the left chamber 12 of the hydraulic cylinder is connected to the oil tank; at the same time, the low point of the cam B8 is disengaged from the valve core 23 of the second one-way valve 9, and the second one-way valve 9 is in a closed state; when the main shaft of the first motor rotates forward, the plunger pump A4 starts, and the high-pressure oil enters the right chamber 11 of the hydraulic cylinder. At the same time, the third one-way valve 13 is controlled to open, and the low-pressure oil in the left chamber 12 of the hydraulic cylinder flows back to the oil tank, and the piston rod 10 moves to the left; This pressure presses the spool of second one-way valve 9, opening it and connecting the oil circuit of hydraulic cylinder right chamber 11 to the oil tank. Simultaneously, the low point of cam B8 disengages the spool of third one-way valve 13, closing it. When the main shaft of first motor 1 rotates in the opposite direction, plunger pump B15 activates, allowing high-pressure oil to enter hydraulic cylinder left chamber 12. Simultaneously, second one-way valve 9 is controlled to open, allowing low-pressure oil in hydraulic cylinder right chamber 11 to flow back to the oil tank, causing piston rod 10 to move rightward, thus achieving bidirectional motion of piston rod 10 and its actuator. The fully symmetrical structures of hydraulic cylinder right chamber 11, left chamber 12, and piston rod 10 offset the effects of downhole high pressure and achieve balance.

[0026] In addition to the above-mentioned preferred embodiments, the present invention has other implementation modes. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection requested by the present invention.

Claims

1. A low-speed pump hydraulic system driving device suitable for use in an underground environment, comprising a first motor (1), a cam A (3), a cam B (8), a cam C (16), a plunger pump A (4), a first one-way valve (5), a right chamber of a hydraulic cylinder (11), and a left chamber of a hydraulic cylinder (12), characterized in that: The first motor (1) is provided with a first dynamic seal and a support (2) on its main shaft, and is connected to a transmission shaft (17). The transmission shaft (17) is provided with a cam A (3) and a cam C (16), respectively, wherein: The connection between the cam A (3) and the transmission shaft (17) is connected by positive meshing, and a screw sleeve (18), a transmission pin (19) and a spring (20) are respectively installed; The cam C (16) and the transmission shaft (17) are connected by reverse meshing and are respectively provided with a screw sleeve (18), a transmission pin (19) and a spring (20).

2. The low-speed pump hydraulic system driving device suitable for underground environment according to claim 1, characterized in that: The main liquid outlet formed by the plunger pump A (4) is connected to the first one-way valve (5), and the first one-way valve (5) is interconnected with the right chamber (12) of the hydraulic cylinder.

3. A low-speed pump hydraulic system driving device suitable for underground environments according to claim 1 or 2, characterized in that: The branch liquid outlet formed by the plunger pump A (4) is also connected to a second one-way valve (9), and the second one-way valve (9) is connected to the oil tank.

4. The low-speed pump hydraulic system driving device suitable for underground environment according to claim 3, characterized in that: The main liquid outlet formed by the plunger pump B (15) is connected to a fourth one-way valve (14), and the fourth one-way valve (14) is interconnected with the left chamber (12) of the hydraulic cylinder.

5. The low-speed pump hydraulic system driving device suitable for underground environment according to claim 1, characterized in that: The branch formed by the plunger pump B (15) is connected to a third one-way valve (13), and the third one-way valve (13) is connected to the oil tank.

6. The low-speed pump hydraulic system driving device suitable for underground environment according to claim 5, characterized in that: It also includes a second motor (6), a second dynamic seal and a support (7) are installed on the main shaft of the second motor (6), and the main shaft is connected to a cam B (8) to drive the rotation of the cam B (8).

7. The low-speed pump hydraulic system driving device suitable for underground environment according to claim 4, characterized in that: The first motor (1) is arranged inside the downhole tool and is composed of a DC brush motor and a reducer.

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