Counterweight adjusting mechanism and pumping unit

Abstract

The invention relates to the technical field of oil pumping units, and discloses a balance weight adjusting mechanism and an oil pumping unit. The counterweight adjusting mechanism comprises two counterweight blocks which are arranged on two opposite sides of the crank and can move along the radial direction of the crank; the crank can rotate around the end part of the crank; the adjusting assembly is connected with the two balancing weights and drives the two balancing weights to alternately and intermittently move; the driving assembly has a first state and a second state and can be switched between the first state and the second state; when the driving assembly is in the first state, along with rotation of the crank, the adjusting assembly is matched with the driving assembly so as to drive the two balancing weights to alternately and intermittently move. The pumping unit comprises a counterweight adjusting mechanism. According to the technical scheme, the technical problem that in the prior art, a balance block cannot be matched with the dynamic requirement of oil well parameters can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of oil pumping units, and in particular to a counterweight adjustment mechanism and an oil pumping unit. Background Art

[0002] The oil pump is a key device used to extract crude oil from oil wells in oil production, and is commonly found in onshore oil fields and offshore platforms. Its core function is to transmit ground power to the downhole pump, overcome the oil layer pressure, and lift the crude oil to the surface.

[0003] In order to offset the inertial force and torque fluctuation caused by the difference in force between the upper and lower strokes when the pump is running, existing pumps are usually equipped with a balance block. However, in the relevant technology, the balance block only adapts to a single working condition and cannot match the dynamic requirements of oil well parameters. Summary of the invention

[0004] The invention discloses a counterweight adjustment mechanism and an oil pumping unit, so as to solve the technical problem that the balancing block in the related art cannot match the dynamic requirements of oil well parameters.

[0005] In order to solve the above problems, the present invention adopts the following technical solutions: In a first aspect, the present invention discloses a counterweight adjustment mechanism, which is applied to an oil pumping unit and comprises: Two counterweights are arranged on opposite sides of the crank and are movable along the radial direction of the crank; a crank, which can be rotated about its end; An adjusting component is connected to the two counterweights to drive the two counterweights to move alternately and intermittently; The driving assembly has a first state and a second state and can switch between the first state and the second state; when the driving assembly is in the first state, as the crank rotates, the adjusting assembly cooperates with the driving assembly to drive the two counterweights to move alternately and intermittently.

[0006] In some embodiments, the adjustment assembly includes a rotating member and two adjustment members; The two adjusting members are respectively arranged in the crank and are respectively connected to the counterweight block to drive the counterweight block to move along the radial direction of the crank; The rotating member is rotatably arranged in the crank, and with the rotation of the rotating member, it intermittently contacts with the two adjusting members, thereby driving the two counterweight blocks to move alternately and intermittently.

[0007] In some embodiments, the adjusting member includes a first worm gear, a first worm and a first lead screw; The first screw is connected with the counterweight block and connected with the center of the first worm gear; the first worm is meshed with the first worm gear; As the rotating member rotates, the rotating member contacts the two first worm gears alternately and drives the first worm gears to rotate.

[0008] In some embodiments, the rotating member includes a rotating portion and two gears; The gear is connected to the first worm, and the rotating part has external teeth, and during the rotation of the rotating part, the external teeth are respectively meshed with the two gears; When the driving assembly is in the first state, as the crank rotates, the rotating part intermittently contacts the driving assembly to drive the rotating part to rotate intermittently.

[0009] In some embodiments, the drive assembly includes a drive member and an abutment portion, the drive member being used to drive the abutment portion to move so as to switch between a first state and a second state; Among them, one side of the rotating part is provided with a plurality of protrusions along its circumference; when the driving assembly is in the first state, as the crank rotates, the plurality of protrusions respectively contact the abutting parts to drive the rotating part to rotate intermittently.

[0010] In some embodiments, the driving member includes a second worm gear, a second worm, a second lead screw and a driving portion; The second screw is connected with the abutment part and is connected with the center of the second worm gear; the second worm is meshed with the second worm gear, and the output shaft of the driving part is connected with the second worm to drive the second worm to rotate.

[0011] In some solutions, a column is provided in the crank along its radial direction, a plurality of clamping parts are respectively provided on opposite sides of the column along its radial direction, and a clamping piece cooperating with the clamping part is provided on the counterweight block; The clamping part has a notch which penetrates radially along the crank, and as the counterweight moves, the clamping piece passes through the notch to be clamped into different clamping parts.

[0012] In some solutions, the clamping member includes a middle portion and two movable portions, and the two movable portions are disposed on opposite sides of the middle portion through an elastic member and can move toward or away from each other.

[0013] In some solutions, the moving part has a first bending structure, and the clamping part has a second bending structure; when the clamping member abuts against the clamping part, the first bending structure and the second bending structure abut against each other to limit the position; And / or, the ends of the two moving parts are respectively provided with inclined guide surfaces.

[0014] In a second aspect, the present invention discloses an oil pumping unit, comprising the counterweight adjustment mechanism in the first aspect.

[0015] The technical solution adopted by the present invention can achieve the following beneficial effects: The counterweight adjustment mechanism of the present invention switches the driving component to the first state when the position of the counterweight needs to be adjusted. With the rotation of the crank, the two counterweights are driven to move alternately and intermittently through the cooperation of the driving component and the adjustment component. The counterweight on one side is adjusted separately in time periods, which can avoid the instantaneous mechanical impact load and resonance risk caused by the synchronous movement of the two counterweights during the rotation of the crank. In addition, the intermittent movement of the two counterweights allows the pumping unit to perform dynamic error compensation and cross-validation through sensor feedback between two actions (such as evaluating the balancing effect after adjusting one of the counterweights and then correcting the other counterweight), reducing overshoot and oscillation of the adjustment trajectory, and achieving a more stable progressive dynamic balance under the premise of ensuring the adjustment accuracy, thereby matching the dynamic requirements of the oil well parameters. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 It is a schematic diagram of the structure of the oil pumping unit disclosed in some embodiments of the present invention; Figure 2 is a schematic diagram of the structure of a counterweight adjustment mechanism disclosed in some embodiments of the present invention; Figure 3 is a schematic diagram of the structure of a counterweight block disclosed in some embodiments of the present invention; Figure 4 yes Figure 3 The enlarged view of point A in the middle; Figure 5 is an axonometric view of a crank disclosed in some embodiments of the present invention; Figure 6 yes Figure 5 The enlarged view of point B in the middle; Figure 7 is a schematic diagram of the connection relationship between the adjustment assembly and the counterweight block disclosed in some embodiments of the present invention; Figure 8 is a partial isometric view of an adjustment assembly disclosed in some embodiments of the present invention; Fig. 9 It is a schematic diagram of the structure of the driving assembly disclosed in some embodiments of the present invention.

[0018] In the figure: 100-counterweight adjustment mechanism, 110-counterweight block, 111-clamping member, 112-moving portion, 113-middle portion, 114-first bending structure, 115-guide surface, 120-crank, 121-column, 122-clamping portion, 123-second bending structure, 124-notch, 130-adjusting assembly, 131-first screw rod, 132-first worm rod, 133-first worm wheel, 134-gear, 135-rotating portion, 136-external teeth, 137-protrusion, 140-driving assembly, 141-abutting portion, 142-second screw rod, 143-second worm wheel, 144-driving portion, 145-second worm rod; 200-Oil pumping unit. DETAILED DESCRIPTION

[0019] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0020] The terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, rather than to describe a specific order or precedence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present invention can be implemented in an order other than those illustrated or described herein, and the objects distinguished by "first", "second", etc. are generally of the same type, and the number of objects is not limited. For example, the first object can be one or more.

[0021] The inventors found that in order to offset the inertial force and torque fluctuations caused by the difference in force between the upper and lower strokes during the operation of the pump, existing pumps are usually equipped with a balance block. However, in the related art, the balance block can only be adjusted in a non-working state, which is only suitable for a single working condition and cannot match the dynamic requirements of oil well parameters.

[0022] The following is combined with Figures 1 to 9 , a counterweight adjustment mechanism 100 and an oil pump 200 provided by the present invention are described in detail through specific embodiments and application scenarios.

[0023] Some embodiments of the present invention provide a counterweight adjustment mechanism 100 for use in an oil pumping unit, including a crank 120 , an adjustment assembly 130 , a drive assembly 140 , and two counterweight blocks 110 .

[0024] like Figure 2As shown, two counterweights 110 are disposed on opposite sides of the crank 120. The design of symmetrically arranging the two counterweights 110 on both sides of the crank 120 can significantly improve the dynamic balance of the crank 120 by counteracting the rotational centrifugal force through symmetrical counterweights.

[0025] like Figure 2 As shown, the two counterweights 110 can move radially along the crank 120. The radial movement function allows the counterweight 110 to adjust the position of the counterweight 110 on the crank 120 according to the oil well parameters, so as to adjust the length of the lever arm, balance the dynamic load, offset the asymmetric inertia force of external loads such as the sucker rod and the liquid column, and reduce the torque fluctuation and vibration when the crank 120 rotates.

[0026] like Figure 1 As shown, the crank 120 can rotate around its end. In this embodiment, the rotating end of the crank 120 is connected to the reduction box of the oil pumping unit, and the crank 120 is driven to rotate by the power of the oil pumping unit motor. In addition, the crank 120 is also connected to the walking beam of the oil pumping unit through a rod, so that the walking beam is driven to rotate by the rotation of the crank 120 to achieve the purpose of oil production.

[0027] like Figure 7 As shown, the adjustment component 130 is connected to the two counterweights 110 to drive the two counterweights 110 to move alternately and intermittently. The adjustment component 130 drives the two counterweights 110 to move alternately and intermittently, and adjusts the counterweight on one side separately in time periods, which can avoid the instantaneous mechanical shock load and resonance risk caused by the synchronous movement of the two counterweights 110 during the rotation of the crank 120. In addition, the intermittent movement of the two counterweights 110 allows the pumping unit to perform dynamic error compensation and cross-validation through sensor feedback between two actions (such as evaluating the balancing effect after adjusting one of the counterweights 110 and then correcting the other counterweight 110), reducing overshoot and oscillation of the adjustment trajectory, and achieving a more stable progressive dynamic balance under the premise of ensuring the adjustment accuracy.

[0028] like Fig. 9 As shown, the driving assembly 140 has a first state and a second state, and can switch between the first state and the second state; when the driving assembly 140 is in the first state, as the crank 120 rotates, the adjusting assembly 130 cooperates with the driving assembly 140 to drive the two counterweights 110 to move alternately and intermittently. When the driving assembly 140 is in the first state, the kinetic energy of the rotation of the crank 120 is used to trigger the adjusting assembly 130 in a time-sharing manner, driving the counterweights 110 on both sides to move alternately, which not only avoids the power surge and mechanical interference of synchronous adjustment, but also matches the angular velocity of the crank 120 through intermittent action, so that the counterweight adjustment and the system inertia change naturally match, thereby achieving precise balance without an additional independent power source.

[0029] Correspondingly, when the driving assembly 140 is in the second state, the crank 120 will not contact the adjusting assembly 130 during the rotation, and thus the movement of the counterweight 110 cannot be adjusted.

[0030] As a preferred embodiment of the present invention, the drive assembly 140 is located at the downstroke position of the crank 120. During the downstroke, the crank 120 is at a low position, and the drive assembly 140 can be directly fixed to the ground foundation without the need for additional high-altitude brackets or suspension structures, thereby reducing the complexity of installation. During the downstroke stage, the gravitational potential energy of the crank 120 and the sucker rod system reaches a peak value, and the drive assembly 140 uses this gravitational potential energy to convert it into the kinetic energy required to adjust the counterweight 110, thereby reducing the load on the motor that drives the crank 120 to rotate.

[0031] like Figure 7 As shown, the adjustment mechanism includes a rotating member and two adjustment members, the two adjustment members are respectively arranged in the crank 120 and are respectively connected to the counterweight 110 to drive the counterweight 110 to move along the radial direction of the crank 120. The two adjustment members drive the two counterweights 110 to move respectively, and the load of the adjustment members is smaller than that of using one adjustment member to control the movement of the two counterweights 110. In addition, the two adjustment members can achieve the purpose of driving the two counterweights 110 to move alternately.

[0032] like Figure 7 As shown, the rotating member is rotatably disposed in the crank 120, and as the rotating member rotates, it intermittently contacts the two adjusting members, thereby driving the two counterweights 110 to move alternately and intermittently. The rotating member, as the driving core, converts the continuous rotation of the crank 120 into driving the counterweights 110 on both sides by rotating and establishing the alternating cooperation between the two adjusting members and the driving assembly 140.

[0033] like Figure 7 and Figure 8 As shown, the adjusting member includes a first worm wheel 133, a first worm 132 and a first screw 131. The first screw 131 is connected with the counterweight 110 and is connected with the center of the first worm wheel 133. The first worm 132 is meshed with the first worm wheel 133. As the rotating member rotates, the rotating member contacts the two first worms 132 alternately and drives the first worm 132 to rotate. When the worm rotates, the worm and the worm wheel are meshed to drive the worm wheel and the screw to rotate, and the screw is connected with the counterweight 110, thereby driving the counterweight 110 to move. In addition, by utilizing the self-locking characteristics of the worm wheel and the worm, the unexpected displacement of the counterweight 110 caused by vibration or inertia can also be eliminated.

[0034] like Figure 7 and Figure 8As shown, the rotating member includes a rotating part 135 and two gears 134; the gear 134 is connected to the first worm 132, and the rotating part 135 has external teeth 136. During the rotation of the rotating part 135, the external teeth 136 are respectively meshed with the two gears 134; wherein, when the driving assembly 140 is in the first state, as the crank 120 moves, the rotating part 135 is intermittently in contact with the driving assembly 140, so as to drive the rotating part 135 to rotate intermittently. When the driving assembly 140 is in the first state, as the crank 120 rotates, the rotating part 135 is intermittently in contact with the driving assembly 140, so that the rotating part 135 rotates intermittently, and in the process of rotation, the rotating part 135 is intermittently in contact with the two gears 134 through its external teeth 136, so that the gravitational potential energy generated during the rotation of the crank 120 is transmitted to the worm through the gear 134, so as to achieve the purpose of driving the two counterweights 110 to move alternately and intermittently.

[0035] like Fig. 9 As shown, the driving assembly 140 includes a driving member and an abutment portion 141, and the driving member is used to drive the abutment portion 141 to move so as to switch between the first state and the second state. When the driving assembly 140 is in the first state, as the crank 120 rotates, the rotating portion 135 intermittently contacts with the abutment portion 141, thereby driving the rotating portion 135 to rotate intermittently, and finally achieving the purpose of driving the two counterweights 110 to move alternately and intermittently. When the driving assembly 140 is in the second state, the rotation of the crank 120 will not cause the rotating portion 135 to contact with the abutment portion 141, thereby failing to drive the rotating portion 135 to rotate. The driving member adjusts the height of the abutment portion 141 by driving the movement of the abutment portion 141, thereby causing the abutment portion 141 to cooperate with the rotating portion 135, or causing the rotating portion 135 to not contact with the rotating portion 135.

[0036] like Figure 8 As shown, one side of the rotating part 135 is provided with a plurality of protrusions 137 along its circumference; when the driving assembly 140 is in the first state, as the crank 120 rotates, the plurality of protrusions 137 respectively contact the abutting part 141 to drive the rotating part 135 to rotate intermittently. The periodic collision triggering of the plurality of protrusions 137 arranged in the circumferential direction and the abutting part 141 realizes a purely mechanical time-sharing drive. During the first rotation of the crank 120, one of the protrusions 137 is triggered by collision with the abutting part 141 to drive one of the counterweights 110 to move; during the Nth rotation of the crank 120, one of the protrusions 137 is triggered by collision with the abutting part 141 to drive the other counterweight 110 to move. Repeat the above steps to realize the alternating intermittent movement of the two counterweights 110.

[0037] Wherein, N can be 2, 3, 4, 5 or more, which is not limited in this embodiment.

[0038] As a preferred embodiment of the present invention, the number of the protrusions 137 is four, and by reasonably designing the position of the abutting portion 141 , after each protrusion 137 collides with the abutting portion 141 , the rotation angle of the rotating portion 135 is 90 degrees.

[0039] like Fig. 9 As shown, the driving member includes a second worm gear 143, a second worm 145, a second lead screw 142 and a driving portion 144. The second lead screw 142 is connected with the abutment portion 141 and is connected with the center of the second worm gear 143; the second worm 145 is meshed with the second worm gear 143, and the output shaft of the driving portion 144 is connected with the second worm 145 to drive the second worm 145 to rotate. The motor drives the second worm 145 to rotate. Since the second worm 145 is meshed with the second worm gear 143, the second worm gear 143 drives the second lead screw 142 to rotate, and drives the abutment portion 141 to move, thereby switching the driving assembly 140 between the first state and the second state.

[0040] Furthermore, by utilizing the self-locking characteristics of the second worm 145 and the second worm wheel 143 , it is possible to avoid the collision of the protrusion 137 with the abutting portion 141 , thereby preventing the abutting portion 141 from being displaced.

[0041] As a preferred embodiment of this embodiment, the driving unit 144 is a motor.

[0042] In this embodiment, the contact surface between the abutment portion 141 and the protrusion 137 is an inclined surface. The inclined surface design significantly reduces the impact force of the collision through the principle of vector decomposition of force: when the protrusion 137 contacts the inclined surface of the abutment portion 141, the collision force can be decomposed into a normal force perpendicular to the inclined surface and a tangential force parallel to the inclined surface, effectively reducing the instantaneous stress of the contact surface, and at the same time, the tangential force component is converted into an axial thrust of the driving screw through the worm self-locking.

[0043] like Figure 5 and Figure 6 As shown, a column 121 is provided in the crank 120 along its radial direction, and a plurality of clamping parts 122 are respectively provided on opposite sides of the column 121 along its radial direction, and the counterweight 110 is provided with a clamping member 111 that cooperates with the clamping member 122. Through the cooperation between the clamping member 111 and the clamping member 122, when the crank 120 rotates, the counterweight 110 transmits the centrifugal force to the column 121 through the clamping member 122, which can effectively suppress the lateral shear overload of the counterweight 110 on the first screw rod 131 caused by the centrifugal force generated by the rotation of the crank 120, and avoid the thread stress concentration caused by the first screw rod 131 being subjected to the lateral component force.

[0044] like Figure 6As shown, the clamping part 122 has a notch 124 that penetrates radially along the crank 120, and as the counterweight 110 moves, the clamping member 111 passes through the notch 124 to be clamped into different clamping parts 122. The notch 124 allows the clamping member 111 to quickly align with different clamping parts 122 as the counterweight 110 moves, so that the movement of the counterweight 110 along the radial direction of the crank 120 is not restricted, and the clamping member 111 can be clamped into different clamping parts 122 as the counterweight 110 moves.

[0045] like Figure 3 and Figure 4 As shown, the clamping member 111 includes a middle portion 113 and two moving portions 112. The two moving portions 112 are arranged on opposite sides of the middle portion 113 through elastic members and can move toward or away from each other. When the clamping member 111 passes through the notch 124, the two moving portions 112 are squeezed and move toward the middle portion 113. During this process, the elastic member stores elastic potential energy. When the clamping member 111 passes through the notch 124, the elastic potential energy of the elastic member is released, driving the two moving portions 112 to move away from the middle portion 113 and away from each other, so that the clamping member 111 stops at the clamping portion 122.

[0046] As a preferred embodiment of the present invention, the elastic member is a plurality of springs. Specifically, the number of the elastic members may be 1, 2, 3, 4 or more, which is not limited in the present embodiment.

[0047] In this embodiment, end surfaces of the two moving parts 112 away from the middle part 113 are respectively provided with wedge-shaped surfaces, so that the two moving parts 112 can move towards the middle part 113 when the clamping member 111 passes through the notch 124 .

[0048] like Figure 4 and Figure 6 As shown, the moving part 112 has a first bending structure 114, and the clamping part 122 has a second bending structure 123; when the clamping member 111 stops against the clamping part 122, the first bending structure 114 and the second bending structure 123 stop and limit. This structure adopts a bidirectional bending interlocking design. When the clamping member 111 and the clamping part 122 cooperate, the first bending structure 114 and the second bending structure 123 are used to directly transmit the centrifugal force generated by the rotation of the crank 120 to the column 121 by using the rigid surface contact of the first bending structure 114 and the second bending structure 123, thereby reducing the shear force of the first screw rod 131 and increasing the service life of the first screw rod 131.

[0049] like Figure 4 As shown, the ends of the two moving parts 112 are respectively provided with inclined guide surfaces 115. By providing the inclined guide surfaces 115 on the moving parts 112, the guide parts decompose the radial pressure into a force driving the moving parts 112 to move horizontally, thereby facilitating the two moving parts 112 to move toward each other to pass through the notch 124.

[0050] Some embodiments of the present invention also provide an oil pumping unit, such as Figure 1 As shown, a weight adjustment mechanism 100 is included.

[0051] The pumping unit also includes a donkey head, a walking beam, a motor, a reducer and a connecting rod. The rotating end of the crank 120 is connected to the reduction box of the pumping unit, and the crank 120 is driven to rotate by the power of the pumping unit motor. In addition, the crank 120 is also connected to the walking beam of the pumping unit through a rod. The donkey head is set at the end of the walking beam, and the rotation of the crank 120 drives the walking beam to rotate periodically to achieve the purpose of oil production.

[0052] In addition, it should be noted that the scope of the methods and devices in the embodiments of the present invention is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved. For example, the described methods may be performed in an order different from that described, and various steps may be added, omitted, or combined. In addition, features described with reference to certain examples may be combined in other examples.

[0053] The above description is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A counterweight adjustment mechanism, applied to an oil pump, characterized in that: include: Two counterweights are arranged on opposite sides of the crank and are movable along the radial direction of the crank; a crank, which can be rotated about its end; An adjusting component connected to the two counterweight blocks to drive the two counterweight blocks to move alternately and intermittently; The driving assembly has a first state and a second state and can switch between the first state and the second state; when the driving assembly is in the first state, as the crank rotates, the adjusting assembly cooperates with the driving assembly to drive the two counterweights to move alternately and intermittently.

2. A counterweight adjustment mechanism according to claim 1, characterized in that: The adjusting assembly comprises a rotating member and two adjusting members; The two adjusting members are respectively arranged in the crank and are respectively connected to the counterweight block to drive the counterweight block to move along the radial direction of the crank; The rotating member is rotatably disposed in the crank, and as the rotating member rotates, it intermittently contacts the two adjusting members, thereby driving the two counterweight blocks to move alternately and intermittently.

3. A counterweight adjustment mechanism according to claim 2, characterized in that: The adjusting member comprises a first worm wheel, a first worm and a first screw; The first screw is connected with the counterweight block and connected with the center of the first worm wheel; the first worm is meshed with the first worm wheel; As the rotating member rotates, the rotating member contacts the two first worm gears alternately and drives the first worm gears to rotate.

4. A counterweight adjustment mechanism according to claim 3, characterized in that: The rotating member includes a rotating part and two gears; The gear is connected to the first worm, the rotating part has external teeth, and during the rotation of the rotating part, the external teeth are respectively meshed with the two gears; Wherein, when the driving assembly is in the first state, as the crank rotates, the rotating part intermittently contacts the driving assembly to drive the rotating part to rotate intermittently.

5. A counterweight adjustment mechanism according to claim 4, characterized in that: The driving assembly comprises a driving member and an abutment portion, wherein the driving member is used to drive the abutment portion to move so as to switch between a first state and a second state; Wherein, a plurality of protrusions are provided along the circumference of one side of the rotating part; when the driving assembly is in the first state, as the crank rotates, the plurality of protrusions respectively contact the abutting parts to drive the rotating part to rotate intermittently.

6. A counterweight adjustment mechanism according to claim 5, characterized in that: The driving member includes a second worm wheel, a second worm, a second lead screw and a driving part; The second screw is cooperatively connected with the abutment portion and is connected with the center of the second worm wheel; the second worm is meshed with the second worm wheel, and the output shaft of the driving portion is connected with the second worm to drive the second worm to rotate.

7. A counterweight adjustment mechanism according to claim 1, characterized in that: A column is provided in the crank along its radial direction, and a plurality of clamping parts are respectively provided on opposite sides of the column along its radial direction, and the counterweight block is provided with a clamping piece matched with the clamping part; The clamping portion has a notch which penetrates radially along the crank, and as the counterweight moves, the clamping piece passes through the notch to be clamped into different clamping portions.

8. A counterweight adjustment mechanism according to claim 7, characterized in that: The clamping member comprises a middle portion and two moving portions. The two moving portions are arranged on opposite sides of the middle portion through elastic members and can move towards or away from each other.

9. A counterweight adjustment mechanism according to claim 8, characterized in that: The movable portion has a first bending structure, and the clamping portion has a second bending structure; when the clamping member abuts against the clamping portion, the first bending structure and the second bending structure abut against each other to limit position; And / or, the ends of the two moving parts are respectively provided with inclined guide surfaces.

10. An oil pumping unit, characterized in that: It comprises the counterweight adjustment mechanism described in any one of claims 1-9.

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