A multi-stage centrifugal pump axial force hydraulic balance structure

Abstract

The present invention belongs to the technical field of axial force balancing, and in particular to an axial force hydraulic balancing structure of a multi-stage centrifugal pump. The following scheme is proposed, including a shell and a balancing component installed inside the shell, the balancing component including a balancing drum; a balancing drum is installed inside the shell, a rotating shaft is fixedly installed inside the balancing drum, a guide groove is provided on the surface of the balancing drum, a lock key is provided on the right side surface of the rotating shaft, and a cross bar is installed on the outside of the rotating shaft; during the use of the present invention, when the pressure changes greatly, the adjustment of a small distance cannot effectively balance the axial force. At this time, the hydraulic oil inside the oil storage cylinder will be sucked in by the action of the control end through the oil inlet pipe, and then the sucked hydraulic oil will be pumped out through the oil outlet pipe. Since the oil outlet pipe and the end oil pipe are connected to each other, the pumped out hydraulic oil will stretch the hydraulic head through the end oil pipe, thereby adjusting the position between the right side plate and the fixed plate.

Description

Technical Field

[0001] The present invention relates to the technical field of axial force balancing, and in particular to an axial force hydraulic balancing structure of a multi-stage centrifugal pump. Background Art

[0002] During the use of multi-stage centrifugal pumps, axial force imbalance is a common problem that affects the performance and reliability of key components. When high-pressure fluid acts on the end faces of rotating or reciprocating parts, significant axial force will be generated. If it is not effectively balanced, it will cause problems such as increased mechanical loss, risk of seal failure, and reduced life and accuracy. Therefore, an axial force hydraulic balancing structure is required.

[0003] However, the axial force balancing structure of the prior art may have a part of the residual axial force that cannot be balanced during use, or the balance adjustment process is limited, and the adjustment of the axial force is still insufficient.

[0004] Therefore, a multi-stage centrifugal pump axial force hydraulic balance structure is required. Summary of the Invention

[0005] The present invention proposes a multi-stage centrifugal pump axial force hydraulic balancing structure, which solves the problem in the prior art that the axial force balancing structure of the prior art will have a part of the residual axial force that cannot be balanced during use, or the balance adjustment process is limited, and the adjustment of the axial force is still insufficient.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A multi-stage centrifugal pump axial force hydraulic balancing structure includes a housing and a balancing assembly installed inside the housing, wherein the balancing assembly includes a balancing drum;

[0008] The cam is fixedly mounted on the outside of the housing, and a guide groove is provided on the surface of the cam, and a lock key is provided on the right surface of the shaft. A cross bar is sleeved on the outside of the shaft, and a key slot is provided on the inside of the cross bar at a position corresponding to the lock key. A right side plate is fixedly mounted on the right side of the cross bar, and a water outlet is provided on the inside of the right side plate. A fixing plate is sleeved on the outside of the cross bar, and a water inlet is provided on the inside of the fixing plate. A side plate is fixedly mounted on the side of the fixing plate, and a fixing bolt is installed through the inside of the side plate. A first low-pressure pipe is installed at the top of the housing between the balance drum and the fixing plate, and a low-pressure port is installed at the right side of the right side plate at the bottom of the housing, and a second low-pressure pipe is installed for circulation behind the low-pressure port, and the second low-pressure pipe is flow-connected with the first low-pressure pipe. A sealing plate is installed at the right end of the rotating shaft, and a sealing end plate is installed on the right side of the sealing plate.

[0009] Preferably, a hydraulic lift is installed on the side of the water inlet, and an end oil pipe is fixedly installed on the other end of the hydraulic lift. An oil outlet pipe is connected to the top of the end oil pipe, and an oil storage cylinder is installed on the other end of the oil storage cylinder, and an oil inlet pipe is connected to the other end of the oil inlet pipe. The other end of the oil inlet pipe is connected to the control end.

[0010] Preferably, the balancing drum and the rotating shaft are fixed to each other, and the guide grooves are distributed in an array outside the balancing drum.

[0011] Preferably, the fixing plate forms a hollow structure through the water inlet, and the fixing plate forms a sealing structure with the shell through the cooperation between the side plate and the fixing bolts.

[0012] Preferably, the sizes of the fixing plate and the right side plate match each other, and the fixing plate and the right side plate do not fit each other.

[0013] Preferably, the right side plate forms a circulation structure through the water inlet, and the right side plate forms a rotation structure with the rotating shaft through the cooperation between the cross bar and the key slot.

[0014] Preferably, the cross bar forms a snap-fit structure with the key slot and the lock key, the cross bar forms a detachable structure with the rotating shaft through the lock rod, and the lock rod passes through the interior of the rotating shaft.

[0015] Preferably, the hydraulic lifting device is installed through the fixed plate, and two groups of the hydraulic lifting devices are symmetrically installed inside the fixed plate.

[0016] Preferably, the right side plate forms a translation structure with the fixed plate through the cooperation between the hydraulic lifting and the end oil pipe.

[0017] The present invention proposes a multi-stage centrifugal pump axial force hydraulic balance structure. Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1. During the use of the present invention, when the pressure changes greatly, the adjustment of the small distance cannot effectively balance the axial force. At this time, the hydraulic oil inside the oil storage cylinder will be sucked in through the oil inlet pipe through the control end, and then the sucked hydraulic oil will be pumped out through the oil outlet pipe. Since the oil outlet pipe and the end oil pipe are connected to each other, the pumped out hydraulic oil will stretch the hydraulic head through the end oil pipe, thereby adjusting the position between the right side plate and the fixed plate.

[0019] 2. During the use of the present invention, the balance drum and the rotating shaft are fixed to each other, so the balance drum will be driven by the rotating shaft to rotate. At the same time, the left side of the balance drum is in contact with the high-pressure end of the multi-stage pump impeller. Therefore, the left side of the rotating shaft is also the high-pressure end, which can guide the liquid entering the device so that the liquid flows from the left side of the balance drum to the right side of the balance drum. In this process, the pressure of the high-pressure liquid will gradually decrease as it flows to the right. In the pump body, the liquid pressure is higher at the impeller on the side close to the balance drum, and the pressure at the balance drum is opposite to that at the impeller, which can offset the pressure generated by the impeller, thereby reducing the axial force inside the device and protecting the pump body.

[0020] 3. During the use of the present invention, the liquid in the gap between the right side plate and the fixed plate will flow out to the right side of the right side plate through the water outlet opened inside the right side plate, and the outflow position is connected to the first low-pressure pipe through the low-pressure port. The first low-pressure pipe is connected to the input port of the pump body. Therefore, the pressure of the first low-pressure pipe is equal to that of the input port, which can form a pressure difference between the balance drum and the right side plate. This pressure difference is opposite to the force direction at the impeller, which can offset the axial force generated inside the device and improve the stability of the device during use.

[0021] 4. During the use of the present invention, the right side plate will make a slight displacement outside the rotating shaft. When the pressure at the impeller changes, the pressure of the liquid flowing into the device will also change. Therefore, the liquid will produce different thrusts on the right side plate. At this time, the right side plate will make a slight displacement at the position of the rotating shaft. Therefore, the distance between the right side plate and the fixed plate will also change. At this time, the liquid pressure on both sides of the right side plate will also change accordingly, so that different reverse forces are generated to balance the axial force. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the overall structure of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0023] Figure 2 It is a schematic cross-sectional view of the axial force hydraulic balance structure of a multi-stage centrifugal pump according to the present invention.

[0024] Figure 3 This is a schematic diagram of the cross-sectional structure of the shell of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0025] Figure 4 It is a schematic diagram of the internal structure of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0026] Figure 5 This is a schematic diagram of the internal right side structure of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0027] Figure 6This is a left-side structural schematic diagram of the balance drum of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0028] Figure 7 This is a schematic diagram of the right side plate installation structure of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0029] Figure 8 This is a schematic diagram of the installation structure of the balance drum and fixed plate of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0030] Figure 9 This is a schematic diagram of the cross-sectional structure of the right side plate of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0031] Figure 10 This is a schematic diagram of the cross-sectional structure of the rotating shaft of the axial force hydraulic balance structure of the multi-stage centrifugal pump of the present invention.

[0032] In the figure: 1. Shell; 2. Balance drum; 3. Rotating shaft; 4. Guide groove; 5. Cross bar; 6. Keyway; 7. Lock key; 8. Lock rod; 9. Right side plate; 10. Water outlet; 11. Fixed plate; 12. Water inlet; 13. Side plate; 14. Fixing bolt; 15. Hydraulic head; 16. End oil pipe; 17. Oil storage cylinder; 18. Oil inlet pipe; 19. Oil outlet pipe; 20. Control end; 21. First low-pressure pipe; 22. Low-pressure port; 23. Second low-pressure pipe; 24. Sealing plate; 25. Sealing end plate. DETAILED DESCRIPTION

[0033] 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. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] See also Figure 1-10 , the present invention provides a technical solution: a multi-stage centrifugal pump axial force hydraulic balancing structure, comprising a housing 1 and a balancing assembly installed inside the housing 1, the balancing assembly comprising a balancing drum 2;

[0035] The housing 1 is provided with a balancing drum 2, a rotating shaft 3 is fixedly installed inside the balancing drum 2, a guide groove 4 is provided on the surface of the balancing drum 2, a lock key 7 is provided on the right side surface of the rotating shaft 3, a cross bar 5 is provided on the outside of the rotating shaft 3, a key slot 6 is provided on the inside of the cross bar 5 at a position corresponding to the lock key 7, a right side plate 9 is fixedly installed on the right side of the cross bar 5, a water outlet 10 is provided inside the right side plate 9, a fixing plate 11 is provided on the outside of the cross bar 5, a water inlet 12 is provided inside the fixing plate 11, and the fixing plate 11 is provided with a water inlet 12. 1 is fixedly installed with a side plate 13, and a fixing bolt 14 is installed inside the side plate 13. A first low-pressure pipe 21 is installed at the top of the shell 1 between the balance drum 2 and the fixed plate 11. A low-pressure port 22 is installed at the bottom of the shell 1 on the right side of the right side plate 9. A second low-pressure pipe 23 is installed behind the low-pressure port 22. The second low-pressure pipe 23 is fluidly connected to the first low-pressure pipe 21. A sealing plate 24 is installed at the right end of the rotating shaft 3, and a sealing end plate 25 is installed on the right side of the sealing plate 24.

[0036] Furthermore, a hydraulic lift 15 is installed on the side of the water inlet 12, and an end oil pipe 16 is fixedly installed on the other end of the hydraulic lift 15. An oil outlet pipe 19 is connected to the top of the end oil pipe 16, and an oil storage cylinder 17 is installed on the other end of the oil storage cylinder 17. The other end of the oil storage cylinder 17 is connected to the oil inlet pipe 18, and the other end of the oil inlet pipe 18 is connected to the control end 20.

[0037] Furthermore, the balance drum 2 and the rotating shaft 3 are fixed to each other, and the guide grooves 4 are distributed in an array on the outside of the balance drum 2. During use, the balance drum 2 and the rotating shaft 3 are fixed to each other, so the balance drum 2 will be driven by the rotating shaft 3 to rotate. At the same time, the left side of the balance drum 2 is in contact with the high-pressure end of the multi-stage pump impeller. Therefore, the left side of the rotating shaft 3 is also the high-pressure end, which can guide the liquid entering the device so that the liquid flows from the left side of the balance drum 2 to the right side space of the balance drum 2. In this process, the pressure of the high-pressure liquid will gradually decrease as it flows to the right. In the pump body, the liquid pressure at the impeller on the side close to the balance drum 2 is higher, and the pressure at the balance drum 2 is opposite to that at the impeller, which can offset the pressure generated by the impeller, thereby reducing the axial force inside the device and protecting the pump body.

[0038] Furthermore, the fixed plate 11 forms a hollow structure through the water inlet 12, and the fixed plate 11 forms a sealing structure with the shell 1 through the cooperation between the side plate 13 and the fixing bolts 14. The liquid flowing through the balance drum 2 and between the balance drum 2 and the fixed plate 11 will flow into the gap between the right side plate 9 through the water inlet 12. Since the diameter of the water inlet 12 is small, the pressure of the liquid decreases due to the throttling effect when flowing through, and a pressure difference is formed on the left and right sides of the fixed plate 11. When the fixed plate 11 is sealed by the side plate 13, water is prevented from flowing out from the edge to affect the use of the device.

[0039] Furthermore, the sizes of the fixed plate 11 and the right side plate 9 match each other, and the fixed plate 11 and the right side plate 9 do not fit each other. The sizes of the fixed plate 11 and the right side plate 9 match each other, so they can form an independent shape. When in use, water flows through the water inlet 12 into the gap between the right side plate 9. Since the gap is small, it has a decompression effect on the water flow, and the sizes of the right side plate 9 and the fixed plate 11 match each other to prevent liquid from flowing out from other places and affecting use.

[0040] Furthermore, the right side plate 9 forms a circulation structure through the water inlet 12, and the right side plate 9 forms a rotating structure with the rotating shaft 3 through the cooperation between the cross bar 5 and the keyway 6. When in use, the liquid in the gap between the right side plate 9 and the fixed plate 11 will flow out to the right side of the right side plate 9 through the water outlet 10 opened inside the right side plate 9, and the outflow position is connected to the first low-pressure pipe 21 through the low-pressure port 22. The first low-pressure pipe 21 is connected to the input port of the pump body. Therefore, the pressure of the first low-pressure pipe 21 is equal to that of the input port, so a pressure difference can be formed between the balance drum 2 and the right side plate 9. This pressure difference is opposite to the force direction at the impeller, which can offset the axial force generated inside the device and improve the stability of the device during use.

[0041] Furthermore, the cross bar 5 forms a locking structure through the key slot 6 and the lock key 7, and the cross bar 5 forms a detachable structure through the lock rod 8 and the rotating shaft 3. The lock rod 8 runs through the interior of the rotating shaft 3. When in use, the cross bar 5 is engaged with the lock key 7 through the key slot 6 opened on the inner wall, and can form a locking fixed structure with the rotating shaft 3, so that the cross bar 5 will also rotate when the rotating shaft 3 rotates, and the cross bar 5 can be fixed. At the same time, the cross bar 5 is fixed by the lock rod 8 on the left side during installation, which avoids the cross bar 5 from being dislocated inside the device and improves the overall stability of the device.

[0042] Furthermore, the hydraulic head 15 is installed through the fixed plate 11, and two groups of hydraulic heads 15 are symmetrically installed inside the fixed plate 11. When in use, the two groups of hydraulic heads 15 are installed through the inside of the fixed plate 11. Therefore, when in use, the hydraulic head 15 can drive the right side plate 9 to move by the drive of the end oil pipe 16, thereby improving the overall stability of the device, adjusting the gap width between the right side plate 9 and the fixed plate 11, and thus adjusting the gap size according to the different pump body pressures, so that the device can adapt to various pump bodies and improve the flexibility of the device. In addition, when the device is in use, the self-adjustment ability of the right side plate 9 is limited. When the adjustment ability of the device is insufficient, the gap between the right side plate 9 and the fixed plate 11 can be assisted by the drive of the hydraulic head 15, further facilitating the device to adapt to different pressures.

[0043] Furthermore, the right side plate 9 forms a translation structure with the fixed plate 11 through the cooperation between the hydraulic lift 15 and the end oil pipe 16. During use, the right side plate 9 will make a small displacement outside the rotating shaft 3. When the pressure at the impeller changes, the pressure of the liquid flowing into the device will also change. Therefore, the liquid will produce different thrusts on the right side plate 9. At this time, the right side plate 9 will make a small displacement at the position of the rotating shaft 3. Therefore, the distance between the right side plate 9 and the fixed plate 11 will also change. At this time, the liquid pressure on both sides of the right side plate 9 will also change accordingly, so that different reverse forces are generated to balance the axial force.

[0044] Working principle: First, the balance drum 2 and the rotating shaft 3 are fixed to each other, so the balance drum 2 will be driven by the rotating shaft 3 to rotate, and at the same time, the left side of the balance drum 2 is in contact with the high-pressure end of the multi-stage pump impeller, so the left side of the rotating shaft 3 is also the high-pressure end, which can guide the liquid entering the device so that the liquid flows from the left side of the balance drum 2 to the right side of the balance drum 2. In this process, the pressure of the high-pressure liquid will gradually decrease as it flows to the right. In the pump body, the liquid pressure at the impeller on the side close to the balance drum 2 is higher, and the pressure at the balance drum 2 is opposite to that at the impeller, which can offset the pressure generated by the impeller, thereby reducing the axial force inside the device and protecting the pump body. The liquid that has been decompressed by the balance drum 2 will be connected to the water inlet of the pump body through the first low-pressure pipe 21 at the contact position between the balance drum 2 and the fixed plate 11. At this time, the axial force generated by the pump body has been balanced to a certain extent by the balance drum 2, and then the remaining liquid will circulate through the water inlet 12 inside the fixed plate 11 and flow into the gap between the right side plate 9. Because the diameter of the water inlet 12 is small, the pressure of the liquid is reduced due to the throttling effect when it flows through, forming a pressure difference on the left and right sides of the fixed plate 11. When the fixed plate 11 is sealed by the side plate 13, it prevents water from flowing out of the edge and affecting the use of the device. The water flows through the water inlet 12 and flows into the gap between the right side plate 9. Because the gap is small, it has a decompression effect on the water flow, and the right side plate 9 and the fixed plate 11 are matched in size to prevent the liquid from flowing out from elsewhere and affecting the use. There are two sets of hydraulic head 15 installed inside the fixed plate 11, so the hydraulic head 15 can drive the right side plate 9 to move by the drive of the end oil pipe 16 when in use, thereby improving the overall stability of the device, adjusting the gap width between the right side plate 9 and the fixed plate 11, and thus adjusting the gap size according to the different pump body pressures, so that the device can adapt to various pump bodies and improve the flexibility of the device. In addition, the self-adjustment ability of the right side plate 9 is limited when the device is in use. When the adjustment ability of the device is insufficient, it can be adjusted by The driving of the hydraulic lift 15 assists in adjusting the gap between the right side plate 9 and the fixed plate 11, further facilitating the device to adapt to different pressures. The liquid in the gap between the right side plate 9 and the fixed plate 11 will flow out to the right side of the right side plate 9 through the water outlet 10 opened inside the right side plate 9, and the outflow position is connected to the first low-pressure pipe 21 through the low-pressure port 22. The first low-pressure pipe 21 is connected to the input port of the pump body. Therefore, the pressure of the first low-pressure pipe 21 is equal to that of the input port, which can form a pressure difference between the balance drum 2 and the right side plate 9. This pressure difference is opposite to the force direction at the impeller, which can offset the axial force generated inside the device and improve the stability of the device during use.

[0045] When the device is in use, the right side plate 9 will make a slight displacement outside the rotating shaft 3. When the pressure at the impeller changes, the pressure of the liquid flowing into the device will also change. Therefore, the liquid will produce different thrusts on the right side plate 9. At this time, the right side plate 9 will make a slight displacement at the position of the rotating shaft 3. Therefore, the distance between the right side plate 9 and the fixed plate 11 will also change. At this time, the liquid pressure on both sides of the right side plate 9 will also change accordingly, so that different reverse forces are generated to balance the axial force. However, when the pressure changes greatly, the adjustment of the slight distance cannot effectively balance the axial force. At this time, the hydraulic oil inside the oil storage cylinder 17 will be sucked in through the action of the control end 20 through the oil inlet pipe 18, and then the sucked hydraulic oil will be pumped out through the oil outlet pipe 19. Since the oil outlet pipe 19 is interconnected with the end oil pipe 16, the pumped out hydraulic oil will stretch the hydraulic head 15 through the end oil pipe 16, thereby adjusting the position between the right side plate 9 and the fixed plate 11.

[0046] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A multi-stage centrifugal pump axial force hydraulic balancing structure, comprising a housing (1) and a balancing assembly installed inside the housing (1), characterized in that: The balancing assembly comprises a balancing drum (2); A balancing drum (2) is installed inside the housing (1), a rotating shaft (3) is fixedly installed inside the balancing drum (2), a guide groove (4) is provided on the surface of the balancing drum (2), a lock key (7) is provided on the right side surface of the rotating shaft (3), a cross bar (5) is sleevedly installed on the outside of the rotating shaft (3), a key slot (6) is provided inside the cross bar (5) at a position corresponding to the lock key (7), a right side plate (9) is fixedly installed on the right side of the cross bar (5), a water outlet (10) is provided inside the right side plate (9), a fixed plate (11) is sleevedly installed on the outside of the cross bar (5), and a water inlet (12) is provided inside the fixed plate (11). A side plate (13) is fixedly installed on the side of the fixed plate (11), and a fixing bolt (14) is installed through the inside of the side plate (13). A first low-pressure pipe (21) is installed at the top of the shell (1) between the balance drum (2) and the fixed plate (11). A low-pressure port (22) is installed at the bottom of the shell (1) on the right side of the right side plate (9). A second low-pressure pipe (23) is installed behind the low-pressure port (22). The second low-pressure pipe (23) is connected to the first low-pressure pipe (21). A sealing plate (24) is installed at the right end of the rotating shaft (3), and a sealing end plate (25) is installed on the right side of the sealing plate (24).

2. The axial force hydraulic balance structure of a multi-stage centrifugal pump according to claim 1, characterized in that: A hydraulic lift (15) is installed on the side of the water inlet (12), and an end oil pipe (16) is fixedly installed on the other end of the hydraulic lift (15). An oil outlet pipe (19) is connected to the upper side of the end oil pipe (16), and an oil storage cylinder (17) is installed to the other end of the oil storage cylinder (17), and an oil inlet pipe (18) is connected to the other end of the oil inlet pipe (18). The other end of the oil inlet pipe (18) is connected to the control end (20).

3. The axial force hydraulic balance structure of a multi-stage centrifugal pump according to claim 1, characterized in that: The balancing drum (2) and the rotating shaft (3) are fixed to each other, and the guide grooves (4) are distributed in an array outside the balancing drum (2).

4. The axial force hydraulic balance structure of a multi-stage centrifugal pump according to claim 1, characterized in that: The fixing plate (11) forms a hollow structure through the water inlet (12), and the fixing plate (11) forms a sealing structure with the housing (1) through the cooperation between the side plate (13) and the fixing bolt (14).

5. The axial force hydraulic balance structure of a multi-stage centrifugal pump according to claim 1, characterized in that: The dimensions of the fixing plate (11) and the right side plate (9) match each other, and the fixing plate (11) and the right side plate (9) do not fit each other.

6. The axial force hydraulic balance structure of a multi-stage centrifugal pump according to claim 1, characterized in that: The right side plate (9) forms a flow structure through the water inlet (12), and the right side plate (9) forms a rotation structure with the rotating shaft (3) through the cooperation between the cross bar (5) and the key slot (6).

7. The axial force hydraulic balance structure of a multi-stage centrifugal pump according to claim 1, characterized in that: The cross bar (5) forms a snap-fit structure with the key slot (6) and the lock key (7), and the cross bar (5) forms a detachable structure with the rotating shaft (3) through the lock rod (8), and the lock rod (8) passes through the interior of the rotating shaft (3).

8. The axial force hydraulic balance structure of a multi-stage centrifugal pump according to claim 2, characterized in that: The hydraulic lifting device (15) is installed through the fixed plate (11), and two groups of the hydraulic lifting devices (15) are symmetrically installed inside the fixed plate (11).

9. The multi-stage centrifugal pump axial force hydraulic balance structure according to claim 1, characterized in that: The right side plate (9) forms a translation structure with the fixed plate (11) through the cooperation between the hydraulic head (15) and the end oil pipe (16).

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