Double-lead-screw lifting mechanism and oil pumping unit

Abstract

The invention discloses a double-lead-screw lifting mechanism and an oil pumping unit. The double-lead-screw lifting mechanism comprises an operation lead screw nut pair unit and a balance weight lead screw nut pair unit. The counterweight lead screw nut pair unit is a lead screw nut pair without a self-locking characteristic; the operation lead screw nut pair unit comprises a first lead screw, a first nut and a first guide frame. The counterweight lead screw nut pair unit comprises a second lead screw, a second nut and a second guide frame; the first lead screw is in transmission connection with the second lead screw; and the motor assembly is used for driving the first lead screw or the second lead screw to rotate. The oil pumping unit comprises an oil well pump and a double-lead-screw lifting mechanism, and a plunger rod of the oil well pump is connected with a first nut of the operation lead screw nut pair unit. Transmission between the two lead screws is used for replacing a traditional rigging and a traditional pulley, the strength is higher, larger working loads can be borne, and breakage accidents are not prone to occurring.

Description

Technical Field

[0001] The present invention belongs to the technical field of lifting mechanisms, and in particular relates to a double-screw lifting mechanism and an oil pumping unit. Background Art

[0002] At present, in oil production or drilling scenarios, tower-type lifting mechanisms are mostly used. Specifically, a pulley is installed on the tower body, and a rigging is carried on the pulley. One end of the rigging is connected to an operating rod (such as a drill rod, a sucker rod, etc.), and the other end is connected to a winch. The winch reels the rigging to achieve up and down reciprocating motion of the other end of the rigging, thereby achieving lifting / lowering motion. In order to reduce energy loss, a counterweight is usually installed on the rigging on the side where the winch is located to balance the load weight of the operation at the other end of the rigging, so that the winch can work better.

[0003] The problem with this type of tower lifting mechanism is that the weight of both ends of the rigging is pressed on the pulley, which requires very high shaft strength of the pulley and the strength of the rigging. Once the rigging breaks or the pulley fails during operation, a serious accident is likely to occur. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to address the deficiencies in the above-mentioned prior art and provide a double-screw lifting mechanism and an oil pumping unit, which utilizes the transmission between the double screws to replace traditional rigging and pulleys, has higher strength, can withstand a larger workload, and is less prone to breakage accidents.

[0005] The first aspect of the present invention discloses a double-screw lifting mechanism, comprising: a working screw-nut pair unit and a counterweight screw-nut pair unit; the counterweight screw-nut pair unit is a screw-nut pair without self-locking characteristics;

[0006] The operating screw-nut subunit includes a first screw, a first nut and a first guide frame, wherein the first nut is sleeved on the first screw, and the first guide frame is used to limit the rotational freedom of the first nut, and the first nut can move up and down along the first guide frame;

[0007] The counterweight screw and nut sub-unit includes a second screw, a second nut and a second guide frame, wherein the second nut is sleeved on the second screw, and the second guide frame is used to limit the rotational freedom of the second nut, and the second nut can move up and down along the second guide frame;

[0008] The first screw and the second screw are in driving connection;

[0009] It also includes a motor assembly, which is used to drive the first screw or the second screw to rotate.

[0010] The above-mentioned double-screw lifting mechanism also includes a base, and the first guide frame and the second guide frame can be detachably mounted on the base. The distance between the first guide frame and the second guide frame is adjustable, and the first screw and the second screw are connected by a gear pair.

[0011] In the above-mentioned double-screw lifting mechanism, the first nut includes a first nut part, a first slider part and a first load part, the first load part is fixed on the first nut part, the first slider part and the first load part are fixed, and the first slider part is installed on the slide rail of the first guide frame.

[0012] In the above-mentioned double-screw lifting mechanism, the second nut includes a second nut part, a second slider part and a second load part, the second load part is fixed on the second nut part, the second slider part and the second load part are fixed, and the second slider part is installed on the slide rail of the second guide frame.

[0013] In the above-mentioned double-screw lifting mechanism, a counterweight block is detachably mounted on the second load portion.

[0014] The above-mentioned double-screw lifting mechanism, the second load part includes a back plate, a bottom plate and two ribs, the second nut part and the second slider part are both fixed to the back plate, the rear edge of the bottom plate is fixed to the bottom of the back plate, the two ribs are installed at the angle between the back plate and the bottom plate, and the back plate, bottom plate and two ribs constitute the accommodating space for the counterweight block.

[0015] In the above-mentioned double-screw lifting mechanism, a suspension rod for installing a counterweight block is installed below the base plate.

[0016] The second aspect of the present invention further discloses an oil pumping unit, comprising an oil pump and the double-screw lifting mechanism as described in the first aspect, wherein the plunger rod of the oil pump is connected to the first nut of the working screw-nut subunit.

[0017] Compared with the prior art, the present invention has the following advantages: an operating screw-nut sub-unit realizes the lifting operation function, and a counterweight screw-nut sub-unit realizes the counterweight of the lifted load. The transmission between the screws replaces the traditional rigging and pulley mechanism. The weight of the load and the counterweight are mainly pressed on the screw, and the strength of the screw is far superior to that of the rigging and pulley, thereby ensuring that there is no risk of breakage, the operation is more stable, and it is not easily disturbed by external factors.

[0018] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a structural diagram of the double-screw lifting mechanism.

[0020] Figure 2 for Figure 1 Left view of .

[0021] Figure 3 A cross-sectional view of the operating screw-nut pair unit.

[0022] Figure 4 It is a cross-sectional view of the counterweight screw nut subunit.

[0023] Figure 5 This is the structural principle diagram of the oil pumping unit.

[0024] Figure 6 This is a three-dimensional schematic diagram of the transmission mechanism of the oil pumping unit.

[0025] Description of the accompanying drawings:

[0026] 1—first screw; 2—first nut; 3—first guide frame;

[0027] 4—Second lead screw; 5—Second nut; 6—Second guide frame;

[0028] 7—motor assembly; 8—base; 9—first gear;

[0029] 10—Second gear; 11—Intermediate gear; 12—Counterweight;

[0030] 13—slide rail; 14—oil pump; 2-1—first nut;

[0031] 2-2—first slider; 2-3—first load portion; 5-1—second nut portion;

[0032] 5-2—Second slider portion; 5-3—Second load portion; 14-1—Plunger rod;

[0033] 14-2—Plunger. DETAILED DESCRIPTION

[0034] like Figure 1 As shown in FIG. 4 , a double-screw lifting mechanism comprises: an operating screw-nut pair unit and a counterweight screw-nut pair unit; the counterweight screw-nut pair unit is a screw-nut pair without a self-locking feature. In this embodiment, preferably, both the operating screw-nut pair unit and the counterweight screw-nut pair unit are ball screw-nut pairs;

[0035] The operating screw-nut subunit includes a first screw 1, a first nut 2 and a first guide frame 3. The first nut 2 is sleeved on the first screw 1. The first guide frame 3 is used to limit the rotational freedom of the first nut 2. The first nut 2 can move up and down along the first guide frame 3.

[0036] The counterweight screw and nut subunit includes a second screw 4, a second nut 5 and a second guide frame 6. The second nut 5 is sleeved on the second screw 4. The second guide frame 6 is used to limit the rotational freedom of the second nut 5. The second nut 5 can move up and down along the second guide frame 6.

[0037] The first screw 1 is in transmission connection with the second screw 4;

[0038] It also includes a motor assembly 7, which is used to drive the first screw 1 or the second screw 4 to rotate. In this embodiment, the motor assembly 7 preferably drives the first screw 1. The motor assembly 7 is composed of a servo motor and a planetary reducer, and the output shaft of the planetary reducer is connected to the first screw 1.

[0039] In this embodiment, a base 8 is also included. The first guide frame 3 and the second guide frame 6 can be detachably mounted on the base 8. The distance between the first guide frame 3 and the second guide frame 6 is adjustable. The first screw 1 and the second screw 4 are connected by a gear pair. The motor assembly 7 is mounted on a gantry on the base 8.

[0040] It should be noted that the base 8 has installation stations at different positions for the first guide frame 3 and the second guide frame 6 (the guide frames are installed using bolts). The purpose of setting the installation stations at different positions is to adjust the distance between the first screw 1 and the second screw 4, and then install gear pairs with different tooth ratios; the tooth ratio between the first gear 9 and the second gear 10 can determine the rotation ratio of the first screw 1 and the second screw 4, and then determine the stroke ratio between the first nut 2 and the second nut 5, and further adjust the weight balance between the workload and the counterweight.

[0041] It should be noted that the gear pair includes the first gear 9 and the second gear 10 , and also includes an intermediate gear 11 between the first gear 9 and the second gear 10 . The intermediate gear 11 is mounted on a column in the middle of the base 8 .

[0042] In actual use, the number of teeth of the second gear 10 is generally greater than the number of teeth of the first gear 9, so that the second nut 5 does not have to travel too far when carrying the counterweight, which helps to reduce the wear of the second nut 5 during long-term use and helps to extend the life of the second nut 5.

[0043] If the counterweight on the second nut 5 is not sufficient to match the workload on the first nut 2 , it is possible to consider reducing the number of teeth on the second gear 10 so that the number of teeth on the second gear 10 is smaller than that on the first gear 9 , thereby achieving the force amplification effect of the counterweight.

[0044] In this embodiment, the first nut 2 includes a first nut portion 2-1, a first slider portion 2-2 and a first load portion 2-3, the first load portion 2-3 is fixed on the first nut portion 2-1, the first slider portion 2-2 and the first load portion 2-3 are fixed, and the first slider portion 2-2 is installed on the slide rail 13 of the first guide frame 3.

[0045] The first load part 2-3 includes a first back plate, a first bottom plate and two first ribs. The first nut part 2-1 and the first slider part 2-2 are both fixed to the first back plate. The rear edge of the first bottom plate is fixed to the bottom of the first back plate. The two first ribs are installed at the angle between the first back plate and the first bottom plate.

[0046] In actual use, the first base plate is used to connect with the workload. The combination of the first back plate, the first base plate and the two first ribs can facilitate the lifting of the workload placed on the upper surface of the first base plate, and facilitate the connection of rod-type loads under the first base plate.

[0047] In this embodiment, the second nut 5 includes a second nut portion 5-1, a second slider portion 5-2 and a second load portion 5-3, the second load portion 5-3 is fixed on the second nut portion 5-1, the second slider portion 5-2 and the second load portion 5-3 are fixed, and the second slider portion 5-2 is installed on the slide rail 13 of the second guide frame 6.

[0048] In this embodiment, a counterweight 12 is detachably mounted on the second load portion 5 - 3 .

[0049] In this embodiment, the second load part 5-3 includes a second back plate, a second bottom plate and two second ribs. The second nut part 5-1 and the second slider part 5-2 are fixed to the second back plate. The rear edge of the second bottom plate is fixed to the bottom of the second back plate. The two second ribs are installed at the angle between the second back plate and the second bottom plate. The back plate, bottom plate and two ribs constitute the accommodating space for the counterweight block 12.

[0050] In this embodiment, a suspension rod for mounting the counterweight 12 is installed below the second bottom plate.

[0051] In actual use, the counterweight 12 can be installed below the second base plate through a suspension rod, or can be installed on the upper surface of the second base plate, and the specific selection can be made according to actual needs.

[0052] like Figure 5 and Figure 6 As shown, the present invention further discloses an oil pumping unit, comprising an oil pump 14 and the double-screw lifting mechanism, wherein the plunger rod 14 - 1 of the oil pump 14 is connected to the first nut 2 of the working screw-nut subunit.

[0053] Specifically, the oil pump 14 includes a plunger 14-2, a plunger rod 14-1, an oil pipe, a casing, an oil inlet valve and an oil outlet valve. The oil pump 14 relies on the plunger rod 14-1 to drive the plunger 14-2 to move up and down in the oil pipe to pump oil. The casing wraps the oil pipe and is connected to the formation; upstroke (plunger upward): the plunger rod 14-1 drives the plunger 14-2 upward, and the crude oil column in the oil pipe above the plunger 14-2 is lifted upward as a whole. Low pressure is formed below the plunger 14-2, the oil inlet valve (bottom fixed valve) is opened, and the formation crude oil flows into the pump chamber below the plunger 14-2. The oil outlet valve (on the plunger 14-2) is closed to prevent the crude oil above from flowing back. Downstroke (plunger 14-2 moves downward): the plunger rod 14-1 drives the plunger 14-2 downward, compressing the crude oil in the pump chamber; the pressure increases, the oil inlet valve closes, preventing the crude oil from returning to the formation, and the oil outlet valve opens, allowing the pressurized crude oil to enter the oil pipe space above the plunger 14-2, and the height of the crude oil column above the plunger 14-2 increases.

[0054] The cycle repeats: Each upstroke lifts a section of crude oil in the tubing, drawing new oil into the pump chamber; each downstroke discharges the new oil into the tubing. The continuous up-and-down motion of plunger 14-2 intermittently lifts the underground crude oil to the surface, section by section, through the alternating opening and closing of the one-way valves (the inlet and outlet valves) (controlled by differential pressure).

[0055] When the present invention is used, first, a suitable counterweight 12 is installed on the second load part 5-3 of the second nut 5. The counterweight 12 can be installed above the second load part 5-3 or below it, depending on the actual situation. The motor assembly 7 (servo motor + reducer) is started to drive the first screw 1 to rotate. During the rotation of the first screw 1, it is driven by the driving force of the motor assembly 7 and the driving force transmitted by the second screw 4, making it easier for the first screw 1 to drive the first nut 2 to lift the plunger rod 14-1 of the oil pump 14. When the first nut 2 is lifted upward, the second nut 5 carries the counterweight downward. Conversely, when the first nut 2 moves downward, the second nut 5 carries the counterweight upward.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent structural change made to the above embodiment based on the technical essence of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A double screw lifting mechanism, characterized in that: include: A working screw nut pair unit and a counterweight screw nut pair unit; the counterweight screw nut pair unit is a screw nut pair without self-locking characteristics; The operating screw-nut subunit includes a first screw, a first nut and a first guide frame, wherein the first nut is sleeved on the first screw, and the first guide frame is used to limit the rotational freedom of the first nut, and the first nut can move up and down along the first guide frame; The counterweight screw and nut sub-unit includes a second screw, a second nut and a second guide frame, wherein the second nut is sleeved on the second screw, and the second guide frame is used to limit the rotational freedom of the second nut, and the second nut can move up and down along the second guide frame; The first screw and the second screw are in driving connection; It also includes a motor assembly, which is used to drive the first screw or the second screw to rotate.

2. A double screw lifting mechanism according to claim 1, characterized in that: It also includes a base, the first guide frame and the second guide frame are both detachably mounted on the base, the distance between the first guide frame and the second guide frame is adjustable, and the first lead screw and the second lead screw are connected through a gear pair.

3. A double screw lifting mechanism according to claim 1, characterized in that: The first nut includes a first nut portion, a first slider portion and a first load portion, the first load portion is fixed on the first nut portion, the first slider portion and the first load portion are fixed, and the first slider portion is installed on a slide rail of the first guide frame.

4. A double screw lifting mechanism according to claim 1, characterized in that: The second nut includes a second nut portion, a second slider portion and a second load portion, the second load portion is fixed on the second nut portion, the second slider portion and the second load portion are fixed, and the second slider portion is installed on the slide rail of the second guide frame.

5. A double screw lifting mechanism according to claim 4, characterized in that: A counterweight is detachably mounted on the second load portion.

6. A double screw lifting mechanism according to claim 5, characterized in that: The second load-bearing part includes a back plate, a bottom plate and two ribs. The second nut part and the second slider part are both fixed to the back plate. The rear edge of the bottom plate is fixed to the bottom of the back plate. The two ribs are installed at the angle between the back plate and the bottom plate. The back plate, the bottom plate and the two ribs constitute a accommodating space for the counterweight block.

7. A double screw lifting mechanism according to claim 5, characterized in that: A suspension rod for installing a counterweight is installed below the bottom plate.

8. A pumping unit, characterized in that: It comprises an oil pump and a double-screw lifting mechanism according to any one of claims 1 to 7, wherein the plunger rod of the oil pump is connected to the first nut of the working screw nut subunit.

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