Single-chain energy-saving pumping unit

Abstract

The application relates to the technical field of oilfield production equipment, and particularly discloses a single-chain energy-saving oil pumping unit, which comprises a base, a tower base fixedly connected to the base, a supporting table fixedly connected to the top of the tower base, a belt roller rotationally connected to the supporting table, a spline shaft one rotationally connected to the middle part of the tower base, and a chain wheel one rotationally connected to the spline shaft one; a fixing base fixedly connected to the middle part of the tower base, a supporting plate slidingly connected to the fixing base, the supporting plate being in abutment with the fixing base, a connecting base fixedly connected to the supporting plate, a chain wheel two rotationally connected to the connecting base, and a chain arranged between the chain wheel one and the chain wheel two. The application takes the tension change caused by the chain breakage as a trigger signal, and through the mechanical connection of the steel wire rope, the chain breakage failure can automatically trigger the two-protection of the driving power cut-off and the balance block emergency locking in sequence, so that the two malignant chain accidents of the broken chain winding and jamming the chain wheel one and the balance block falling and impacting the oil pumping pump are prevented.

Description

Technical Field

[0001] This invention relates to the field of oilfield production equipment technology, and more specifically, to a single-chain energy-saving pumping unit. Background Technology

[0002] The single-chain pumping unit is a new type of high-efficiency, long-stroke pumping equipment. Its core utilizes a high-strength closed-loop chain to drive a specially flexible sucker rod in a reciprocating up-and-down motion. This model innovatively places the counterweight balancing system at the bottom, acting as a counterweight to the sucker rod, effectively recovering gravitational potential energy during the downstroke and achieving significant energy savings. With its long operating stroke and stable load, it is particularly suitable for deep wells, heavy oil, and offshore platform extraction scenarios, making it a key piece of equipment for improving oilfield economic efficiency.

[0003] This type of pumping unit uses a closed-loop chain-driven polished rod. When sudden situations such as pump jamming occur downhole, the load on the suspension point increases dramatically, easily causing the high-strength chain to break at its weakest point. The broken chain segment can quickly entangle and jam the drive sprocket. If the motor continues to run at this time, the jammed transmission system will generate enormous resistance torque, which will not only severely damage the chain and sprocket teeth, but may also cause the motor to overload and burn out, leading to secondary failures.

[0004] Furthermore, if the drive chain breaks, the counterweight that was originally suspended by it will instantly lose its support and accelerate its fall under the influence of gravity. The rapid fall of the counterweight will forcefully pull the sucker rod string upwards in the opposite direction through the pulley, causing the polished rod at the top of the sucker rod string or the plunger of the pump to strike the pump barrel or other limiting devices with great kinetic energy, which may cause deformation and damage to the pump barrel, or even cause the entire pump system to fail.

[0005] In view of this, we propose a single-chain energy-saving oil pumping unit. Summary of the Invention

[0006] (a) Technical problems to be solved To address the problems existing in the prior art, the present invention provides a single-chain energy-saving pumping unit to solve the technical problem mentioned in the background art where chain breakage during the use of chain pumping units causes further damage to the equipment.

[0007] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: a single-chain energy-saving oil pumping unit, comprising: a base, a tower base fixedly connected thereto, a spline shaft rotatably connected to the middle of the tower base, and a sprocket rotatably connected to the spline shaft rotatably connected to the sprocket. A fixed base is fixedly connected to the middle of the tower base. A support plate is slidably connected to the fixed base. The support plate abuts against the fixed base. A connecting seat is fixedly connected to the support plate. A sprocket two is rotatably connected to the connecting seat. A chain is wound between the sprocket one and the sprocket two. Multiple limiting rods are provided, which pass through the support plate and are slidably connected to it, and the limiting rods limit the position of the support plate; A counterweight mechanism is installed inside the tower base, and the counterweight structure is used to balance the weight of the sucker rod; A drive mechanism is mounted on the base. The drive structure is used to drive the spline shaft to rotate and to disconnect the power connection with the spline shaft in time when the chain is damaged.

[0008] Furthermore, the counterweight mechanism includes: Spring one is fixedly connected between the support plate and the fixed base; There are two guide rails, both of which are fixed to the tower base. A balance block is slidably connected between the two guide rails through a guide shoe. A guide groove is provided in the middle of the balance block. The movable frame is slidably connected to the guide groove of the balance block. The movable frame is detachably connected to the chain. The balance block is fixedly connected to a connecting belt. The top of the tower base is fixedly connected to a support platform. The support platform is rotatably connected to a belt roller. The connecting belt is wound around the belt roller.

[0009] Furthermore, the driving structure includes: The motor and the reducer are both fixedly connected to the base. The output shaft of the motor is fixedly connected to the input shaft of the reducer. The output shaft of the reducer is fixedly connected to a splined shaft two. A support base is fixedly connected to the base, and a spline sleeve is slidably connected to the support base. The spline sleeve is splinedly connected to spline shaft one and spline shaft two. A limiting component is disposed on the upper side of the support base, and the limiting component is used to switch the connection state between the spline sleeve and the spline shaft.

[0010] Furthermore, the limiting component includes: A connecting ring is rotatably connected to one side of the spline sleeve. A rectangular shell is fixed to the upper side of the support base. A limiting plate is fixed to the connecting ring, and the limiting plate is inserted into the rectangular shell. A fixed frame is fixed to the upper side of the support base, and the fixed frame is slidably connected to a limiting pin, which is inserted into the rectangular shell and the limiting plate.

[0011] Furthermore, the limiting pin is fixedly connected to a retaining ring, and a spring is fixedly connected between the retaining ring and the retaining frame.

[0012] Furthermore, the support base is slidably connected to a sliding rod, the sliding rod is fixedly connected to the connecting ring, and a spring is fixedly connected between the connecting ring and the support base, the spring being sleeved on the sliding rod.

[0013] Furthermore, a steel wire rope is fixed between the limiting pin and the support plate, and the elastic force of the first spring is greater than that of the second spring.

[0014] Furthermore, it also includes: A protective structure, disposed on the balance weight, is used to limit the balance weight's movement after chain damage. The protective structure includes: There are two connecting plates, both of which are fixed to the upper side of the balance block, and the connecting plates are rotatably connected to the limit frame; A limiting post is rotatably connected to the limiting frame, the limiting post abuts against the guide rail, and a torsion spring is fixedly connected between the connecting plate and the limiting frame.

[0015] Furthermore, the guide rail has a central sliding rail that is flush with the side of the guide rail, and the limiting post abuts against the sliding rail.

[0016] Furthermore, both the sliding rail and the guide rail are provided with spaced limiting grooves, and the limiting grooves of the sliding rail and the guide rail are alternately staggered. The support plate is fixedly connected to a connecting frame, and the connecting frame is fixedly connected to the two sliding rails.

[0017] (III) Beneficial Effects Compared with the prior art, the present invention provides a single-chain energy-saving oil pumping unit, which has the following beneficial effects: 1. This invention uses the tension change caused by chain breakage as a trigger signal. Through a mechanical connection with a steel wire rope, the chain breakage fault automatically triggers a dual protection mechanism: the drive power is cut off sequentially, and the balance block is locked in an emergency. This prevents two catastrophic chain accidents: the broken chain becoming entangled and jamming the sprocket, and the balance block falling and impacting the oil pump. It achieves multiple layers of protection from the source of the fault to secondary disasters.

[0018] 2. When the chain breaks, causing the driven sprocket support plate to move upwards, a pre-set wire rope linkage mechanism immediately activates the limit pin. Under the action of spring three, the spline sleeve slides axially, automatically disconnecting the power transmission between the motor and sprocket one. This design prevents the motor from continuing to drive, thus avoiding further damage to the chain and sprocket one, preventing further chain entanglement and jamming, and minimizing motor burnout due to overload.

[0019] 3. This invention designs a mechanical lock consisting of a sliding rail, a limiting post, and a torsion spring. In case of a malfunction, the support plate moves upward, causing the sliding rail to move and align its groove with the guide rail groove. The falling counterweight causes the limiting post to automatically rotate under the action of the torsion spring and engage in the overlapping groove, reliably locking the counterweight on the rail and completely avoiding the huge impact caused by its free fall, thus protecting the oil pump unit and sucker rod string. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a single-chain energy-saving oil pumping unit according to the present invention; Figure 2 This is a side view of the structure of components such as the tower base and belt rollers in this invention; Figure 3 This is a schematic cross-sectional view of the tower base in this invention; Figure 4 This is a schematic diagram of the structure of components such as the guide rail and the balance block in this invention; Figure 5 This is a cross-sectional view of the fixing base in this invention; Figure 6 This is a structural schematic diagram of the connecting plate and limiting frame, etc., in this invention; Figure 7 This is a schematic diagram of the driving structure in this invention; Figure 8 This is a structural schematic diagram of the support base and spline sleeve, etc., in this invention; Figure 9 This is a cross-sectional view of the spline sleeve and rectangular shell in this invention. Figure 10 This is a cross-sectional view of the guide rail and sliding rail in this invention.

[0021] In the diagram: 1. Base; 2. Tower base; 3. Support platform; 4. Belt roller; 5. Splined shaft one; 6. Sprocket one; 7. Fixed seat; 8. Support plate; 9. Connecting seat; 10. Sprocket two; 11. Chain; 12. Limiting rod; 13. Spring one; 14. Guide rail; 15. Balance block; 16. Moving frame; 17. Connecting belt; 18. Motor; 19. Reducer; 20. Splined shaft two; 21. Support seat; 22. Splined sleeve; 23. Connecting ring; 24. Rectangular shell; 25. Limiting plate; 26. Fixed frame; 27. Limiting pin; 28. Fixed ring; 29. ​​Spring two; 30. Sliding rod; 31. Spring three; 32. Steel wire rope; 33. Connecting plate; 34. Limiting frame; 35. Limiting post; 36. Torsion spring; 37. Sliding rail; 38. Connecting frame. Detailed Implementation

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0023] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0024] In this invention, unless otherwise stated, the directional terms such as "up" and "down" generally refer to the directions shown in the accompanying drawings, or to the vertical, perpendicular, or gravitational direction; similarly, for ease of understanding and description, "left" and "right" generally refer to the left and right shown in the accompanying drawings; "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0025] This invention provides a single-chain energy-saving oil pumping unit, such as... Figures 1-5 As shown, it includes: base 1, tower base 2, support platform 3, belt roller 4, spline shaft 5, sprocket 6, fixed seat 7, support plate 8, connecting seat 9, sprocket 10, chain 11, limit rod 12, spring 13, counterweight mechanism and drive mechanism. A base 1 is fixedly connected to a tower base 2. A support platform 3 is fixedly connected to the top of the tower base 2. A belt roller 4 is rotatably connected to the support platform 3. A spline shaft 5 is rotatably connected to the middle of the tower base 2. A sprocket 6 is rotatably connected to the spline shaft 5. A fixed seat 7 is fixedly connected to the middle of the tower base 2. A support plate 8 is slidably connected to the fixed seat 7. The support plate 8 abuts against the fixed seat 7. A connecting seat 9 is fixedly connected to the support plate 8. A sprocket 10 is rotatably connected to the connecting seat 9. A chain is wound between the sprocket 6 and the sprocket 10. The support plate 8 is slidably connected to the support plate 8, and the limit rod 12 is provided in multiple places. The limit rod 12 limits the support plate 8. A spring 13 is fixed between the support plate 8 and the fixed seat 7. The counterweight mechanism is set in the tower base 2. The counterweight structure is used to balance the weight of the sucker rod. The drive mechanism is set on the base 1. The drive structure is used to drive the spline shaft 5 to rotate. When the chain 11 is damaged, the drive structure will disconnect the power connection with the spline shaft 5 in time.

[0026] In the initial state, the sprockets are wound around sprocket 6 and sprocket 10. Under the tension of the chain 11, the spring 13 is compressed and the support plate 8 is in contact with the base 1. The drive mechanism drives the spline shaft 5 to rotate, which causes the sprocket 6 to drive the chain 11 to rotate. The chain 11 moves around sprocket 6 and sprocket 10.

[0027] like Figure 3 , Figure 4 and Figure 6 As shown, the counterweight mechanism includes: guide rail 14, balance block 15, moving frame 16 and connecting belt 17; There are two guide rails 14, both of which are fixed to the tower base 2. A balance block 15 is slidably connected between the two guide rails 14 through a guide shoe. A guide groove is provided in the middle of the balance block 15. The moving frame 16 is slidably connected to the guide groove of the balance block 15. The moving frame 16 is detachably connected to the chain 11. A connecting belt 17 is fixed to the balance block 15 and is wound around the belt roller 4.

[0028] As chain 11 moves around sprocket 6 and sprocket 10, chain 11 drives moving frame 16 to move. Moving frame 16 moves along the guide groove of balance block 15, thereby realizing the reciprocating up-and-down movement of balance block 15 along two guide rails 14. Balance block 15 balances the weight of sucker rod and recovers and utilizes downstroke energy, reducing power consumption during operation and making this pumping unit more energy-efficient. Balance block 15 drives connecting belt 17 to move, and under the guidance of belt roller 4, the end of the belt moves up and down reciprocatingly, driving sucker rod to pump oil.

[0029] like Figures 7-9 As shown, the drive structure includes: a motor 18, a reducer 19, a splined shaft 20, a support base 21, a splined sleeve 22, and a limit assembly; Both the motor 18 and the reducer 19 are fixedly connected to the base 1. The output shaft of the motor 18 is fixedly connected to the input shaft of the reducer 19. The output shaft of the reducer 19 is fixedly connected to a second spline shaft 20. The support base 21 is fixedly connected to the base 1. A spline sleeve 22 is slidably connected to the support base 21. The spline sleeve 22 is splinedly connected to the first spline shaft 5 and the second spline shaft 20. A limiting component is set on the upper side of the support base 21. The limiting component is used to switch the connection state between the spline sleeve 22 and the first spline shaft 5.

[0030] When pumping oil, the motor 18 is started. The output shaft of the motor 18 drives the input shaft of the reducer 19 to rotate. The output shaft of the reducer 19 drives the second spline shaft 20 to rotate circumferentially. The second spline shaft 20 drives the first spline shaft 5 to rotate through the spline sleeve 22, thereby realizing the circumferential movement of the chain 11 along the first sprocket 6 and the second sprocket 10, causing the balance block 15 to move back and forth along the guide rail 14, and pumping oil.

[0031] After the chain 11 is damaged and broken, the support plate 8 drives the sprocket 10 to move upward under the elastic force of the spring 13. After the chain 11 breaks, since the sprocket 10 is the driven wheel, the chain 11 falls downward under the action of gravity and separates from the sprocket 10.

[0032] like Figure 4 , Figure 5 , Figure 8 and Figure 9 As shown, the limiting assembly includes: a connecting ring 23, a rectangular shell 24, a limiting plate 25, a fixing frame 26, a limiting pin 27, a fixing ring 28, a second spring 29, a sliding rod 30, a third spring 31, and a steel wire rope 32. A connecting ring 23 is rotatably connected to one side of a spline sleeve 22. A rectangular shell 24 is fixedly connected to the upper side of a support base 21. A limiting plate 25 is fixedly connected to the connecting ring 23 and inserted into the rectangular shell 24. A fixing frame 26 is fixedly connected to the upper side of a support base 21. A limiting pin 27 is slidably connected to the fixing frame 26 and inserted into the rectangular shell 24 and the limiting plate 25. A fixing ring 28 is fixedly connected to the limiting pin 27. A second spring 29 is fixedly connected between the fixing ring 28 and the fixing frame 26. A sliding rod 30 is slidably connected to the support base 21. The sliding rod 30 is fixedly connected to the connecting ring 23. A third spring 31 is fixedly connected between the connecting ring 23 and the support base 21 and is sleeved on the sliding rod 30. A steel wire rope 32 is fixedly connected between the limiting pin 27 and the support plate 8. The elastic force of the first spring 13 is greater than that of the second spring 29.

[0033] Because the elastic force of spring 13 is greater than that of spring 29, after chain 11 is damaged and broken, the support plate 8 moves upward and pulls the limit pin 27 through the wire rope 32. The fiber pin moves upward along the fixed frame 26, and the limit pin 27 releases the limit on the limit plate 25. Spring 29 is compressed and, under the action of the elastic force of spring 31, pushes the spline sleeve 22 to slide along the support seat 21. The spline sleeve 22 loses connection with the spline shaft 5, and the motor 18 no longer drives the sprocket 6 to rotate, preventing the sprocket 6 from winding around the chain 11, which would cause the chain 11 to jam the sprocket and damage the equipment.

[0034] like Figure 6 and Figure 10 As shown, it also includes: a protective structure, which is set on the balance block 15. The protective structure is used to limit the balance block 15 after the chain 11 is damaged. The protective structure includes: a connecting plate 33, a limiting frame 34, a limiting post 35, a torsion spring 36, a sliding rail 37 and a connecting frame 38. Two connecting plates 33 are provided, both of which are fixed to the upper side of the balance block 15. The connecting plates 33 are rotatably connected to the limit frame 34. The limit post 35 is rotatably connected to the limit frame 34 and abuts against the guide rail 14. A torsion spring 36 is fixed between the connecting plates 33 and the limit frame 34. The guide rail 14 has a middle sliding rail 37, which is flush with the side of the guide rail 14. The limit post 35 abuts against the sliding rail 37. Both the sliding rail 37 and the guide rail 14 are provided with spaced-apart limit grooves. The limit grooves of the sliding rail 37 and the guide rail 14 are alternately staggered. The support plate 8 is fixedly connected to the connecting frame 38, which is fixedly connected to the two sliding rails 37.

[0035] After the chain 11 breaks, the support plate 8 drives the sliding rail 37 to move upward along the guide rail 14 through the connecting frame 38. When the support plate 8 contacts the top of the limiting rod 12, the limiting rod 12 limits the support plate 8. At this time, the lower groove of the sliding rail 37 overlaps with the limiting groove of the guide rail 14. When the balance block 15 moves downward, under the elastic force of the torsion spring 36, the limiting frame 34 is driven along the connecting plate 33, so that the limiting post 35 is engaged in the limiting groove of the guide rail 14 and the sliding rail 37, so that the balance block 15 stops descending.

[0036] Working principle of the invention: When this oil pumping unit is working, the motor 18 drives the spline shaft 20 to rotate via the reducer 19. The spline shaft 20 drives the spline shaft 5 to rotate via the spline sleeve 22. The spline shaft 5 drives the sprocket 10 to rotate via the sprocket 6 and the chain 11. As the chain 11 moves along the sprocket 6 and the sprocket 10, the balance block 15 is driven to slide back and forth along the guide rail 14 via the moving frame 16. The balance block 15 drives the sucker rod to move up and down back and forth via the end of the connecting belt 17 to pump oil. The limiting post 35 abuts against the guide rail 14 and the sliding rail 37, and the limiting post 35 rotates along the limiting frame 34.

[0037] During the oil extraction process, if chain 11 is damaged or broken, chain 11 will no longer limit sprocket 10. Under the elastic force of spring 13, support plate 8 will drive the parts on it to move upward along fixed seat 7 until the upper end of limit rod 12 of support plate 8 contacts. During the above process, support plate 8 pulls limit pin 27 upward through wire rope 32. Limit pin 27 releases the limit of limit plate 25. Under the elastic force of spring 31, spline sleeve 22 moves to the right along spline shaft 5 and spline shaft 20 until spline sleeve 22 loses connection with spline shaft 5, causing sprocket 6 to lose power and preventing chain 11 from getting wrapped around sprocket 6, causing sprocket 6 to jam and damage the equipment.

[0038] The support plate 8 drives the two sliding rails 37 to move upward along the guide rail 14 via the connecting frame 38, so that the limiting grooves of the sliding rails 37 overlap with the limiting grooves of the guide rail 14. During the downward movement of the limiting post 35, the elastic force of the torsion spring 36 causes the limiting frame 34 to swing and engage the limiting post 35 within the limiting groove of the guide rail 14, stopping the downward movement of the balance block 15 and preventing it from falling and causing impact damage to the pump. The operator needs to replace or repair the chain 11 and then restore the parts of the pumping unit to their initial state, thus putting the pumping unit back into use.

[0039] In all the solutions mentioned above, for connections between two components, welding, bolt and nut connection, bolt or screw connection, or other known connection methods can be selected according to the actual situation. These will not be elaborated here. For all fixed connections mentioned above, welding is preferred. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. A single-chain energy-saving oil pumping unit, characterized in that, include: The base (1) is fixedly connected to the tower base (2), and the middle part of the tower base (2) is rotatably connected to the spline shaft (5), and the spline shaft (5) is rotatably connected to the sprocket (6). A fixed seat (7) is fixedly connected to the middle part of the tower base (2). The fixed seat (7) is slidably connected to a support plate (8). The support plate (8) abuts against the fixed seat (7). The support plate (8) is fixedly connected to a connecting seat (9). The connecting seat (9) is rotatably connected to a sprocket two (10). A chain (11) is wound between the sprocket one (6) and the sprocket two (10). The limiting rod (12) is provided in multiple forms. The multiple limiting rods (12) pass through the support plate (8) and are slidably connected. The limiting rods (12) limit the support plate (8). A counterweight mechanism is installed inside the tower base (2), and the counterweight structure is used to balance the weight of the sucker rod; The drive mechanism is set on the base (1). The drive structure is used to drive the spline shaft (5) to rotate and disconnect the power connection with the spline shaft (5) in time when the chain (11) is damaged.

2. The single-chain energy-saving oil pumping unit according to claim 1, characterized in that, The counterweight mechanism includes: Spring 1 (13) is fixed between the support plate (8) and the fixed seat (7); There are two guide rails (14), both of which are fixed in the tower base (2). A balance block (15) is slidably connected between the two guide rails (14) through a guide shoe. A guide groove is provided in the middle of the balance block (15). The movable frame (16) is slidably connected to the guide groove of the balance block (15). The movable frame (16) is detachably connected to the chain (11). The balance block (15) is fixedly connected to a connecting belt (17). The top of the tower base (2) is fixedly connected to a support platform (3). The support platform (3) is rotatably connected to a belt roller (4). The connecting belt (17) is wound around the belt roller (4).

3. The single-chain energy-saving oil pumping unit according to claim 2, characterized in that, The driving structure includes: The motor (18) and the reducer (19) are both fixed to the base (1). The output shaft of the motor (18) is fixed to the input shaft of the reducer (19). The output shaft of the reducer (19) is fixed to a splined shaft (20). A support base (21) is fixedly connected to the base (1). A spline sleeve (22) is slidably connected to the support base (21). The spline sleeve (22) is splinedly connected to the first spline shaft (5) and the second spline shaft (20). A limiting component is provided on the upper side of the support base (21). The limiting component is used to switch the connection state between the spline sleeve (22) and the spline shaft (5).

4. The single-chain energy-saving oil pumping unit according to claim 3, characterized in that, The limiting component includes: A connecting ring (23) is rotatably connected to one side of the spline sleeve (22). A rectangular shell (24) is fixedly connected to the upper side of the support base (21). A limiting plate (25) is fixedly connected to the connecting ring (23). The limiting plate (25) is inserted into the rectangular shell (24). The fixing frame (26) is fixed to the upper side of the support base (21). The fixing frame (26) is slidably connected to the limiting pin (27). The limiting pin (27) is inserted into the rectangular shell (24) and the limiting plate (25).

5. The single-chain energy-saving oil pumping unit according to claim 4, characterized in that, The limiting pin (27) is fixedly connected to a fixing ring (28), and a spring (29) is fixedly connected between the fixing ring (28) and the fixing frame (26).

6. The single-chain energy-saving oil pumping unit according to claim 4, characterized in that, The support base (21) is slidably connected to a sliding rod (30), the sliding rod (30) is fixedly connected to the connecting ring (23), and a spring three (31) is fixedly connected between the connecting ring (23) and the support base (21). The spring three (31) is sleeved on the sliding rod (30).

7. The single-chain energy-saving oil pumping unit according to claim 5, characterized in that, A steel wire rope (32) is fixed between the limiting pin (27) and the support plate (8), and the elastic force of the first spring (13) is greater than that of the second spring (29).

8. The single-chain energy-saving oil pumping unit according to claim 2, characterized in that, It also includes: A protective structure is disposed on the balance block (15), the protective structure being used to limit the balance block (15) after the chain (11) is damaged, the protective structure comprising: There are two connecting plates (33), both of which are fixed to the upper side of the balance block (15). The connecting plates (33) are rotatably connected to the limit frame (34). The limiting post (35) is rotatably connected to the limiting frame (34). The limiting post (35) abuts against the guide rail (14). A torsion spring (36) is fixed between the connecting plate (33) and the limiting frame (34).

9. The single-chain energy-saving oil pumping unit according to claim 8, characterized in that, The guide rail (14) has a middle sliding rail (37), which is flush with the side of the guide rail (14), and the limiting post (35) abuts against the sliding rail (37).

10. The single-chain energy-saving oil pumping unit according to claim 9, characterized in that, Both the sliding rail (37) and the guide rail (14) are provided with spaced limiting grooves. The limiting grooves of the sliding rail (37) and the guide rail (14) are alternately staggered. The support plate (8) is fixedly connected to a connecting frame (38), and the connecting frame (38) is fixedly connected to the two sliding rails (37).

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