A sequential action binding hydraulic cylinder

Abstract

This invention discloses a sequential action binding hydraulic cylinder, comprising a first cylinder and a second cylinder. One end of the first cylinder has an oil port 1, and the other end has an oil port 2. The first cylinder houses a piston rod body, a piston 1, a guide sleeve, and a piston rod head. The piston 1 divides the first cylinder into a rod-side chamber and a rodless chamber. The second cylinder includes a second cylinder body, a piston rod head, a piston 2, and a piston rod body. The piston rod head has both a rodless chamber oil port and a rod-side chamber oil port. The piston 2 also divides the second cylinder into a rod-side chamber and a rodless chamber. This sequential action binding hydraulic cylinder has the advantages of simple structure, reliable operation, and low manufacturing cost, and can be widely used in engineering machinery requiring sequential action.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder technology, and more specifically to a sequential action binding hydraulic cylinder. Background Technology

[0002] Truck-mounted cranes are a new type of high-efficiency lifting and transportation equipment that integrates lifting and transportation. Their advantages of speed, flexibility, efficiency, convenience, and combined loading, unloading, and transportation have led to their increasing recognition and acceptance by users, and they are widely used in transportation, civil engineering, power, and other fields. To meet the requirements of large lifting radius and lifting height, truck-mounted cranes often contain multi-section telescopic booms. How to achieve the telescopic movement of each boom section is a key design consideration. Common boom telescopic methods for truck-mounted cranes include synchronous telescopic, sequential telescopic, and a combination of sequential and synchronous telescopic. Sequential telescopic is typically used on truck-mounted cranes with large tonnage and many boom sections, which greatly simplifies the internal structure of the boom and improves the reliability of the telescopic structure. Currently, the main methods for achieving sequential boom telescopic on truck-mounted cranes include sequential telescopic circuits controlled by stroke valves and sequential telescopic circuits controlled by the pressure difference of sequence valves. However, current sequential telescopic cylinders and control systems are mostly complex in structure and have many components, resulting in high costs and frequent malfunctions, leading to low system reliability. Therefore, developing a sequential action binding hydraulic cylinder that is simple in structure, reliable in operation, and inexpensive to manufacture is an urgent problem to be solved in the industry. Summary of the Invention

[0003] To address the aforementioned problems, the present invention aims to provide a sequential action binding hydraulic cylinder to achieve sequential extension and retraction of a crane boom.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] A sequential action binding hydraulic cylinder includes a first cylinder and a second cylinder. The first cylinder comprises a cylinder body, a piston rod, a piston, and a piston rod head. One end of the cylinder body has an oil port, and the other end has an oil port. The piston rod, piston, guide sleeve, and piston rod head are installed inside the cylinder body. The piston rod is slidably connected to the guide sleeve. The piston rod head has an oil supply hole for the rodless chamber, an oil supply hole for the rod chamber, and a central oil hole. The piston divides the cylinder body into a rod chamber and a rodless chamber, and the rod chamber communicates with the oil port. A central sleeve is mounted on the piston through a central sleeve guide sleeve. The central sleeve is located in the inner cavity of the piston rod body, and the inner cavity of the central sleeve is a central sleeve channel. The central sleeve channel communicates with the central oil hole on the piston rod head. An oil pipe is provided between the central sleeve and the piston rod body. The oil pipe and the central sleeve form a cylinder rodless cavity channel. The two ends of the cylinder rodless cavity channel communicate with the cylinder rodless cavity oil supply hole and the cylinder rodless cavity respectively opened on the piston rod head. The oil pipe and the piston rod body form a cylinder rod cavity channel. One end of the cylinder rod cavity channel communicates with the cylinder rod cavity through the piston oil hole provided at the piston end, and the other end of the cylinder rod cavity channel communicates with the cylinder rod cavity oil supply hole.

[0006] A center rod is installed on the inner side of the cylinder body. The center rod passes through the center sleeve guide and extends into the inner cavity of the center sleeve. The center rod is slidably connected to the center sleeve guide. An internal hole is opened on the center rod. The inner cavity of the center rod is a center rod channel. The center rod channel communicates with the center sleeve channel. The center rod channel is also connected to the oil outlet through the center rod oil hole at the end of the center rod.

[0007] The second hydraulic cylinder includes a second cylinder body, a second piston rod head, a second piston, and a second piston rod body. The second piston rod head is provided with a rodless chamber oil port and a rod chamber oil port. The second piston divides the second cylinder body into a second rod chamber and a second rodless chamber. The second rod chamber communicates with the second rod chamber oil port through a second rod chamber channel, and the second rodless chamber communicates with the second rodless chamber oil port through a second rodless chamber channel.

[0008] Furthermore, the built-in holes are one or more rows of small holes.

[0009] Furthermore, a sealing element is installed on the central sleeve guide sleeve. Before the piston rod of the hydraulic cylinder extends to its position, the central rod channel is disconnected from the rodless chamber of the hydraulic cylinder, and the sealing element plays a sealing role.

[0010] Furthermore, a stroke valve block and a stroke valve are installed on the outer side of the cylinder body. The stroke valve block is provided with oil hole two and oil hole four. Oil hole two and oil hole four are connected or disconnected through the stroke valve. Oil hole two is connected to the rodless chamber of the cylinder through oil hole one. Oil hole four is connected to the center rod channel and oil port two through oil hole three.

[0011] Furthermore, a ramming block is installed at the end of the second cylinder.

[0012] Furthermore, the rodless chamber oil port on the second piston rod head is connected to oil port two, and the rod chamber oil port on the second piston rod head is connected to oil port one;

[0013] Furthermore, a balance valve is externally connected to the piston rod head, and the oil supply port of the rodless chamber of the cylinder, the oil supply port of the rod chamber of the cylinder, and the central oil port opened on the piston rod head are connected to the oil circuit of the balance valve.

[0014] Furthermore, the balance valve is provided with passage one and passage two. Passage one is provided with check valve one and check valve two. Check valve one is connected to the oil supply port of the rodless chamber of cylinder one, check valve two is connected to the central oil port, and passage two is connected to the oil supply port of the rod chamber of cylinder one.

[0015] Furthermore, an oil tank is provided on the central oil hole through an oil replenishment passage, and a one-way valve is installed on the oil replenishment passage.

[0016] Furthermore, an O-ring is provided between the oil pipe and the piston.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1. This invention is an application of mechanical touch control for sequential extension and retraction, which can realize the sequential extension and retraction of the boom. The structure of the cylinder is simple and compact, the matching hydraulic system is simple and reliable, and the cost is relatively low. It can be widely used in large-tonnage straight boom truck cranes.

[0019] 2. Compared with existing balance valves, the balance valve designed in this invention adds three one-way valves to the original valve block and opens corresponding passages. During operation, only one-way liquid flow is allowed, making the boom extension and retraction operation safer and more reliable. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the fully retracted state of the hydraulic cylinder of the present invention;

[0021] Figure 2 A schematic diagram showing the extended state of a piston rod in a hydraulic cylinder.

[0022] Figure 3 A schematic diagram showing the piston rod of the hydraulic cylinder extended to its full position.

[0023] Figure 4 A schematic diagram showing the extended and fully engaged states of the hydraulic cylinder's two piston rods;

[0024] Figure 5 A schematic diagram showing the retracted state of the second piston rod of the hydraulic cylinder;

[0025] Figure 6 A schematic diagram showing the state where the second piston rod of the hydraulic cylinder is retracted to its final position;

[0026] Figure 7 This is a schematic diagram showing the state of the piston rod of the hydraulic cylinder retracted to its final position.

[0027] Figure 8 A schematic diagram of an existing balancing valve;

[0028] Figure 9 This is a schematic diagram of the balance valve of the present invention;

[0029] Figure 10 This is a hydraulic schematic diagram of the present invention;

[0030] Figure 11 This is an assembly drawing of the piston rod and piston of a hydraulic cylinder.

[0031] Figure 12 This is a schematic diagram of the central tube structure;

[0032] Figure 13 This is a schematic diagram of the structure of cylinder one;

[0033] Figure 14 This is a schematic diagram of the structure of cylinder two.

[0034] The labels in the diagram are as follows:

[0035] 1. Cylinder 1; 11. Cylinder 1; 12. Piston rod 1 rod body; 13. Piston 1; 131. Piston 1 oil hole; 14. Guide sleeve; 15. Piston rod 1 rod head; 16. Oil pipe; 17. O-ring.

[0036] 2. Cylinder 2, 21. Cylinder 2, 22. Piston rod 2 rod head, 23. Piston 2, 24. Piston rod 2 rod body, 25. Rod chamber oil port 5, 26. Rodless chamber oil port;

[0037] 3. Stroke valve block;

[0038] 4. Stroke valve;

[0039] 5. Collision block;

[0040] 6. Center rod; 61. Center rod oil hole;

[0041] 7. Center sleeve guide sleeve;

[0042] 8. Center sleeve;

[0043] 9. Balance valve; 91. Check valve one; 92. Check valve two; 93. Check valve three.

[0044] A. Pathway 1;

[0045] B. Pathway Two;

[0046] A1, Oil supply port of rodless chamber of cylinder 1; A2, Channel of rodless chamber of cylinder 1; A3, Rodless chamber of cylinder 1; A4, Oil hole 1; A5, Oil hole 2.

[0047] B1, Oil supply hole for rod chamber of cylinder 1; B2, Rod chamber passage of cylinder 1; B3, Rod chamber of cylinder 1; B4, Oil port 1; B5, Rod chamber passage of cylinder 2; B6, Rod chamber of cylinder 2.

[0048] C1, central oil hole; C2, central sleeve channel; C3, central rod channel; C4, oil hole three; C5, oil hole four; C6, oil port two; C7, rodless cavity channel of cylinder two; C8, rodless cavity of cylinder two.

[0049] M, Internal hole;

[0050] T, fuel tank. Detailed Implementation

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] like Figure 1-14 As shown, a sequential action binding hydraulic cylinder in this embodiment includes cylinder 1 and cylinder 2.

[0053] like Figure 11 , 12 As shown in Figure 13, the hydraulic cylinder 1 includes a cylinder body 11, a piston rod body 12, a piston 13, and a piston rod head 15; one end of the cylinder body 11 is provided with an oil port B4, and the other end of the cylinder body 11 is provided with an oil port C6; the piston rod body 12, piston 13, guide sleeve 14, and piston rod head 15 are installed inside the cylinder body 11, and the piston rod body 12 is slidably connected to the guide sleeve 14; the piston rod head 15 is externally connected to a balance valve 9, and the piston rod head 15 is provided with an oil supply hole A1 for the rodless chamber of the hydraulic cylinder, an oil supply hole B1 for the rod chamber of the hydraulic cylinder, and a central oil hole C1 that are connected to the oil circuit of the balance valve 9.

[0054] like Figure 9As shown, the balance valve 9 in this embodiment is provided with passage A and passage B. Passage A is provided with check valve 91 and check valve 92. Check valve 91 is connected to the oil supply port A1 of the rodless chamber of the cylinder, and check valve 92 is connected to the central oil port C1. An oil tank T is provided on the central oil port C1 through the oil replenishment passage. Check valve 93 is installed on the oil replenishment passage T. Passage B is connected to the oil supply port B1 of the rod chamber of the cylinder.

[0055] like Figure 11 , 12 As shown in Figure 13, piston 13 divides cylinder 11 into cylinder rod chamber B3 and cylinder rodless chamber A3. Cylinder rod chamber B3 is connected to oil port B4.

[0056] A central sleeve 8 is installed on piston 13 through central sleeve guide sleeve 7. The central sleeve 8 is located in the inner cavity of piston rod 12. The inner cavity of the central sleeve 8 is the central sleeve channel C2, which communicates with the central oil hole C1 on piston rod 15.

[0057] An oil pipe 16 is provided between the central sleeve 8 and the piston rod 12. An O-ring 17 is provided between the oil pipe 16 and the piston 13. The oil pipe 16 and the central sleeve 8 form a cylinder rodless chamber channel A2. The two ends of the cylinder rodless chamber channel A2 are respectively connected to the cylinder rodless chamber oil supply hole A1 and the cylinder rodless chamber A3 opened on the piston rod 15.

[0058] The oil pipe 16 and the piston rod 12 form the cylinder rod chamber passage B2. One end of the cylinder rod chamber passage B2 is connected to the cylinder rod chamber B3 through the piston oil hole 131 provided at the end of the piston 13. The other end of the cylinder rod chamber passage B2 is connected to the cylinder rod chamber oil supply hole B1.

[0059] A center rod 6 is installed inside the cylinder body 11. The center rod 6 passes through the center sleeve guide sleeve 7 and extends into the inner cavity of the center sleeve 8. The center rod 6 and the center sleeve guide sleeve 7 are slidably connected. The inner cavity of the center rod 6 is the center rod channel C3, which communicates with the center sleeve channel C2. The center rod channel C3 communicates with the oil outlet C6 through the center rod oil hole 61 at the end of the center rod 6. An internal hole M is provided on the center rod 6. The internal hole M can be one or more rows of small holes, generally two rows. When the piston rod of the cylinder 1 extends to the end, the internal hole M will slide past the N end face of the center sleeve guide sleeve 7. At this time, the center rod channel C3 communicates with the rodless cavity A3 of the cylinder 1. A seal is installed on the center sleeve guide sleeve 7. Before the piston rod of the cylinder 1 extends to the end, the center rod channel C3 and the rodless cavity A3 of the cylinder 1 are disconnected, and the seal plays a sealing role.

[0060] A stroke valve block 3 and a stroke valve 4 are installed on the outer side of cylinder 11. The stroke valve block 3 has two oil holes, A5 and C5, which are connected or disconnected via the stroke valve 4. Oil hole A5 communicates with the rodless chamber A3 of cylinder 1 via oil hole A4, and oil hole C5 communicates with the center rod channel C3 and oil port C6 via oil hole C4. The stroke valve 4 is normally disconnected, meaning oil hole C5 is disconnected from oil hole A5.

[0061] like Figure 1 and 14 As shown, the second cylinder 2 includes a second cylinder body 21, a second piston rod head 22, a second piston 23, and a second piston rod body 24. A stop block 5 is installed at the end of the second cylinder body 21.

[0062] The piston rod head 22 is provided with a rodless chamber oil port 26 and a rod chamber oil port 25. The rodless chamber oil port 26 is connected to oil port C6, and the rod chamber oil port 25 is connected to oil port B4.

[0063] Piston 23 divides cylinder 21 into rod chamber B6 and rodless chamber C8. Rod chamber B6 is connected to rod chamber port 25 through rod chamber channel B5, and rodless chamber C8 is connected to rodless chamber port 26 through rodless chamber channel C7.

[0064] The hydraulic working principle of this invention is as follows: Figure 10 As shown, when the hydraulic cylinder of this invention extends, oil enters through the oil supply port A1 of the rodless chamber of cylinder 1, and cylinder 1 extends, with the stroke pressed open. Cylinder 2 makes a slight movement, causing the stroke valve 4 to disengage from the stop block 5. After disengagement, the stroke valve 4 closes, and only cylinder 1 can extend. After cylinder 1 has fully extended, the oil supply port A1 of the rodless chamber of cylinder 1 and the central oil port C1 are connected through the internal hole M to the N position of the central sleeve guide sleeve 7, allowing cylinder 2 to continue extending with oil supply. When the hydraulic cylinder of this invention retracts, the stroke valve 4 is initially closed, i.e., the stroke valve 4 is disengaged from the stop block 5. At this time, the rodless chamber A3 of cylinder 1 cannot return oil through the central oil port C1, while the rodless chamber C8 of cylinder 2 returns oil through the central oil port C1. After cylinder 2 has fully retracted, the stroke valve 4 contacts and opens with the stop block 5, and the rodless chamber A3 of cylinder 1 begins to return oil through the stroke valve 4.

[0065] Specific work processes, such as Figure 1-7 As shown, when cylinders 1 and 2 are fully retracted, stroke valve 4 is open, meaning stroke valve 4 is in contact with block 5. Figure 1As shown, the oil inlet channel at this time is as follows: Passage 1 A - Oil supply hole A1 of rodless chamber of cylinder 1 - Passage A2 of rodless chamber of cylinder 1 - Passage A3 of rodless chamber of cylinder 1 - Oil hole 1 A4 - Oil hole 2 A5 - Stroke valve 4 - Oil hole 4 C5 - Oil hole 3 C4 - Oil port 2 C6 - Passage C7 of rodless chamber of cylinder 2 - Passage C8 of rodless chamber of cylinder 2. A small amount of oil is introduced, which pushes the cylinder body 21 of cylinder 2 to move to the right by about 5-8mm, so that the stroke valve 4 is disengaged from the striker 5. The above oil inlet channel is disconnected. At this time, only cylinder 1 can operate.

[0066] like Figure 2 As shown, the piston rod of cylinder 1 extends. At this time, the oil inlet channel is: passage A - check valve 91, cylinder rodless chamber oil supply hole A1 - cylinder rodless chamber channel A2 - cylinder rodless chamber A3. The oil return channel is: cylinder rod chamber oil supply hole B3 - cylinder rod chamber channel B2 - cylinder rod chamber oil supply hole B1 - passage B - oil tank. During the extension of the piston rod of cylinder 1, hydraulic oil can be appropriately replenished into the central sleeve channel C2 through the replenishment channel to avoid the cylinder barrel being deformed due to vacuum negative pressure in the central sleeve 8. The replenishment channel is: oil tank T - check valve 93 - central oil hole C1 - central sleeve channel C2.

[0067] like Figure 3 As shown, when the piston rod 12 of cylinder 1 extends to its position, the central rod 6 slides to its position relative to the central sleeve guide sleeve 7. At this time, the internal hole M on the central rod 6 slides past the N end face of the central sleeve guide sleeve 7. The rodless chamber A3 of cylinder 1 is connected to the central rod channel C3 through the internal hole M. This is also a prerequisite for the extension of the piston rod of cylinder 2. The next action is the extension of the piston rod of cylinder 2.

[0068] like Figure 4 As shown, the oil inlet channel when the piston rod 24 of cylinder 2 is extended and in position is as follows: passage A – check valve 91 – oil supply hole A1 of cylinder 1 rodless chamber – passage A2 of cylinder 1 rodless chamber – cylinder 1 rodless chamber A3 – internal hole M – center rod passage C3 – oil port C6 – oil port C7 of cylinder 2 rodless chamber – oil port C8 of cylinder 2. The oil return channel at this time is as follows: cylinder 2 rod chamber B6 – cylinder 2 rod chamber passage B5 – oil port B4 – cylinder 1 rod chamber B3 – cylinder 1 rod chamber passage B2 – oil supply hole B1 of cylinder 1 rod chamber – passage B – oil tank. At this time, the hydraulic cylinder is in the fully extended state.

[0069] When the hydraulic cylinder needs to retract, if cylinder 2 is not fully retracted, cylinder 1 cannot retract. This is because one of the return oil paths of cylinder 1, the one-way valve 91 connected to the rodless chamber A3 of cylinder 1 – the rodless chamber channel A2 of cylinder 1 – the oil supply port A1 of cylinder 1 only allows liquid to pass in one direction. When one-way valve 91 is closed, this path cannot return oil. Although cylinder 1 has another return oil path, namely, the rodless chamber A3 of cylinder 1 – the center rod channel C3 – the internal hole M – the center sleeve channel C2 – the center oil hole C1 – one-way valve 92 – the passage A – the return oil tank, once cylinder 1 starts to move, it will drive the center sleeve guide sleeve 7 to move to the right. The center rod 6 and the internal hole M on the center rod 6 will move to the left relative to the center sleeve guide sleeve 7, causing the internal hole M to disengage from the N end face of the center sleeve guide sleeve 7, closing the path. Cylinder 1 will stop after a slight movement. Therefore, only the piston rod of cylinder 2 can be retracted first. Figure 5 As shown, the oil inlet channel when the piston rod of cylinder 2 retracts is: passage 2B—oil supply hole B1 of cylinder 1 rod chamber—channel B2 of cylinder 1 rod chamber—channel B3 of cylinder 1 rod chamber—oil port 1 B4—channel B5 of cylinder 2 rod chamber—channel B6 of cylinder 2 rod chamber. The oil return channel at this time is: cylinder 2 rodless chamber C8—channel C7 of cylinder 2 rodless chamber—oil port 2 C6—center rod channel C3—internal hole M—center sleeve channel C2—center oil hole C1—one-way valve 2 92—passage 1A—return tank.

[0070] When the piston rod of cylinder 2 retracts to its position, the impact block 5 mounted on cylinder 2 contacts the stroke valve 4, and the stroke valve 4 is activated, meaning that oil port A5 and oil port C5 are connected. This is a prerequisite for cylinder 1 to retract. Figure 6 As shown, the oil inlet channel at this time is: Passage 2 B - Oil supply hole B1 of rod chamber of cylinder 1 - Passage B2 of rod chamber of cylinder 1 - Passage B3 of rod chamber of cylinder 1 - Oil port 1 B4 - Passage B5 of rod chamber of cylinder 2 - Passage B6 of rod chamber of cylinder 2. The oil return channel at this time is: C8 of rodless chamber of cylinder 2 - Passage C7 of rodless chamber of cylinder 2 - Oil port 2 C6 - Center rod channel C3 - Center sleeve channel C2 - Center oil hole C1 - Check valve 2 92 - Passage 1 A - Return oil tank.

[0071] After the piston rod of cylinder 2 retracts to its position, cylinder 1 retracts as follows. Figure 7As shown, the stroke valve 4 is now open. The oil inlet channel is: passage 2 B - oil supply hole B1 of the rod chamber of cylinder 1 - passage B2 of the rod chamber of cylinder 1 - B3 of the rod chamber of cylinder 1. The oil return channel is: rodless chamber A3 of cylinder 1 - oil hole 1 A4 - oil hole 2 A5 - stroke valve 4 - oil hole 4 C5 - oil hole 3 C4 - center rod passage C3 - internal hole M - center sleeve passage C2 - center oil hole C1 - check valve 2 92 - passage 1 A - return oil tank. At this point, the hydraulic cylinder is fully retracted.

[0072] like Figure 8 As shown, the existing balance valve only has two passages and does not use a check valve, therefore the reliability of the hydraulic cylinder during operation is not high; for example... Figure 9 As shown, this invention adds three check valves to the balance valve 9 and opens corresponding passages, that is, the existing A1 passage is divided into A1 and C1 passages, which only allow liquid to pass through in one direction. Due to the action of check valve 91, the A1 passage can only receive oil; due to the action of check valve 92, the C1 passage can only return oil, making the operation of hydraulic oil safer and more reliable. At the same time, an oil replenishment passage T is added to the C1 passage and controlled by check valve 93 to replenish oil in one direction. On the one hand, it can avoid the cylinder barrel being deformed due to vacuum negative pressure in the central sleeve 8, and on the other hand, it can also prevent the liquid from flowing backward, making it safe and reliable.

Claims

1. A sequential action bundled hydraulic cylinder comprising a cylinder one (1) and a cylinder two (2), characterized in that, The oil cylinder one (1) includes a cylinder one (11), a piston rod one rod body (12), a piston one (13) and a piston rod one rod head (15); the cylinder one (11) is provided with an oil port one (B4) at one end, and the other end of the cylinder one (11) is provided with an oil port two (C6); the cylinder one (11) is internally provided with the piston rod one rod body (12), the piston one (13), a guide sleeve (14) and the piston rod one rod head (15), the piston rod one rod body (12) is in sliding connection with the guide sleeve (14); the piston rod one rod head (15) is provided with an oil cylinder one rodless cavity oil supply hole (A1), an oil cylinder one rod cavity oil supply hole (B1) and a center oil hole (C1); the piston one (13) divides the cylinder one (11) into an oil cylinder one rod cavity (B3) and an oil cylinder one rodless cavity (A3), the oil cylinder one rod cavity (B3) is communicated with the oil port one (B4); the piston one (13) is internally provided with a center sleeve (8) through a center sleeve guide sleeve (7), the center sleeve (8) is located in the inner cavity of the piston rod one rod body (12), the inner cavity of the center sleeve (8) is a center sleeve channel (C2), the center sleeve channel (C2) is communicated with the center oil hole (C1) on the piston rod one rod head (15); an oil pipe (16) is arranged between the center sleeve (8) and the piston rod one rod body (12), the oil pipe (16) and the center sleeve (8) form an oil cylinder one rodless cavity channel (A2), the two ends of the oil cylinder one rodless cavity channel (A2) are communicated with the oil cylinder one rodless cavity oil supply hole (A1) and the oil cylinder one rodless cavity (A3) formed on the piston rod one rod head (15) respectively; the oil pipe (16) and the piston rod one rod body (12) form an oil cylinder one rod cavity channel (B2), one end of the oil cylinder one rod cavity channel (B2) is communicated with the oil cylinder one rod cavity (B3) through a piston one oil hole (131) arranged at the end of the piston one (13), the other end of the oil cylinder one rod cavity channel (B2) is communicated with the oil cylinder one rod cavity oil supply hole (B1); The inner side of the cylinder one (11) is internally provided with a center rod (6), the center rod (6) extends to the inner cavity of the center sleeve (8) through the center sleeve guide sleeve (7), the center rod (6) is in sliding connection with the center sleeve guide sleeve (7); the center rod (6) is provided with an internal hole (M), the inner cavity of the center rod (6) is a center rod channel (C3), the center rod channel (C3) is communicated with the center sleeve channel (C2), and the center rod channel (C3) is communicated with the oil outlet two (C6) through a center rod oil hole (61) arranged at the end of the center rod (6). The oil cylinder two (2) comprises a cylinder two (21), a piston rod two head (22), a piston two (23) and a piston rod two body (24), the piston rod two head (22) is provided with a rodless cavity oil port (26) and a rod cavity oil port (25), the piston two (23) divides the cylinder two (21) into an oil cylinder two rod cavity (B6) and an oil cylinder two rodless cavity (C8), the oil cylinder two rod cavity (B6) is communicated with the rod cavity oil port (25) through an oil cylinder two rod cavity channel (B5), and the oil cylinder two rodless cavity (C8) is communicated with the rodless cavity oil port (26) through an oil cylinder two rodless cavity channel (C7).

2. A sequential action bundled hydraulic cylinder as claimed in claim 1, wherein, The built-in hole (M) is a small hole in one or more rows.

3. A sequence action bundled hydraulic cylinder as claimed in claim 1 or 2, characterized in that, A sealing element is mounted on the center sleeve guide sleeve (7).

4. A sequence-action bundled hydraulic cylinder as claimed in claim 3, wherein, The cylinder one (11) is externally provided with a stroke valve block (3) and a stroke valve (4), the stroke valve block (3) is internally provided with an oil hole two (A5) and an oil hole four (C5), the oil hole two (A5) and the oil hole four (C5) are communicated or disconnected through the stroke valve (4); the oil hole two (A5) is communicated with the oil cylinder one rodless cavity (A3) through an oil hole one (A4), and the oil hole four (C5) is communicated with a center rod channel (C3) and an oil port two (C6) through an oil hole three (C4).

5. A sequence-action bundled hydraulic cylinder as claimed in claim 4, wherein, The end of the cylinder two (21) is provided with a bumper (5).

6. A sequence-action bundled hydraulic cylinder as claimed in claim 5, characterized in that, The rodless cavity oil port (26) provided on the piston rod two head (22) is connected with the oil port two (C6), and the rod cavity oil port (25) provided on the piston rod two head (22) is connected with the oil port one (B4).

7. A sequence action bundled hydraulic cylinder as claimed in claim 6, wherein, The piston rod one head (15) is externally connected with a balance valve (9), and the oil cylinder one rodless cavity oil hole (A1), the oil cylinder one rod cavity oil hole (B1) and the center oil hole (C1) formed in the piston rod one head (15) are communicated with the oil circuit of the balance valve (9).

8. A sequential action bundled hydraulic cylinder as claimed in claim 7, wherein, The balance valve (9) is provided with a passage one (A) and a passage two (B), the passage one (A) is provided with a one-way valve one (91) and a one-way valve two (92), the one-way valve one (91) is communicated with the oil cylinder one rodless cavity oil hole (A1), and the one-way valve two (92) is communicated with the center oil hole (C1), and the passage two (B) is communicated with the oil cylinder one rod cavity oil hole (B1).

9. A sequence-action bundled hydraulic cylinder as claimed in claim 8, characterized in that, The center oil hole (C1) is provided with an oil tank (T) through an oil supplement passage, and the oil supplement passage is provided with a one-way valve three (93).

10. A sequence-action bundled hydraulic cylinder as in claim 1, wherein, An O-shaped ring (17) is arranged between the oil pipe (16) and the piston one (13).

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