A composite oil cylinder

Abstract

The application relates to the technical field of hydraulic transmission equipment, and provides a composite oil cylinder which comprises a cylinder body, a flow guide rod and a piston structure. A piston movement cavity is arranged in the cylinder body, a first oil feeding hole, a second oil feeding hole, a gas injection hole and a liquid injection hole are arranged on the outer wall of the cylinder body, the first oil feeding hole is in communication with one end of the piston movement cavity, the second oil feeding hole is in communication with the other end of the piston movement cavity, one end of the flow guide rod is arranged in the cylinder body, a gas injection channel and a liquid injection channel which are in communication with the outside are arranged in the flow guide rod, the gas injection hole is in communication with the gas injection channel, and the liquid injection hole is in communication with the liquid injection channel, and one end of the piston structure is slidably arranged in the piston movement cavity, and the other end is located outside the cylinder body. The application overcomes the single-function defect of a traditional oil cylinder, and avoids the problem of system structure bulkiness caused by multiple external conveying pipelines.

Description

Technical Field

[0001] This application relates to the technical field of hydraulic transmission equipment, and in particular to a composite cylinder. Background Technology

[0002] Hydraulic transmission technology is widely used in modern industry, providing powerful power support for the efficient operation of various mechanical equipment. It plays a crucial role in many industries, such as construction machinery, aerospace, and metallurgy, significantly improving the automation level and production efficiency of industrial production.

[0003] In some complex industrial equipment, actuators need to perform diverse functions. For situations requiring multiple media to operate, the common practice has been to use external delivery pipelines, pumps, and switching valve assemblies. The flow paths of different media are switched by controlling the opening and closing of the pumps and valves, or multiple additional media delivery devices are used to achieve multi-media control. For example, in the machine tool manufacturing industry, these methods are frequently used when performing operations such as workpiece airtightness testing, cooling, surface impurity removal, and hydraulic support.

[0004] While adding external delivery pipelines, delivery pumps, and switching valve assemblies can meet the basic requirements of multi-media drive, it makes the entire system structure very bulky, occupies a lot of space, and increases the weight and cost of the equipment. Furthermore, the switching valve assembly method suffers from response lag, as the opening and closing of valves takes time, making it difficult to react promptly under rapidly changing operating conditions. Summary of the Invention

[0005] In order to overcome the shortcomings of traditional hydraulic cylinders in terms of single function and avoid the problem of bloated system structure caused by adding external delivery pipelines, delivery pumps and other equipment, this application provides a composite hydraulic cylinder.

[0006] This application provides a composite hydraulic cylinder, which adopts the following technical solution: A composite hydraulic cylinder, comprising: The cylinder body has a piston movement chamber inside it. The outer wall of the cylinder body has a first oil inlet hole, a second oil inlet hole, an air injection hole and a liquid injection hole. The first oil inlet hole is connected to one end of the piston movement chamber, and the second oil inlet hole is connected to the other end of the piston movement chamber. A guide rod, one end of which is inserted into the cylinder body, and the guide rod is provided with an air injection channel and a liquid injection channel that are connected to the outside. The air injection hole is connected to the air injection channel, and the liquid injection hole is connected to the liquid injection channel. A piston structure, wherein one end of the piston structure is slidably disposed within the piston movement chamber, and the other end is located outside the cylinder body.

[0007] By adopting the above technical solution, the piston movement chamber of the cylinder is connected to the first oil inlet and the second oil inlet to drive the piston reciprocating. At the same time, the air injection channel and liquid injection channel of the guide rod are connected to the outside through the air injection hole and liquid injection hole, so that the air injection hole and liquid injection hole on the cylinder can directly inject gas or liquid during the sliding process of the structure. During the operation, the piston structure moves in the piston movement chamber to complete linear drive, while the built-in air injection channel and liquid injection channel of the guide rod allow gas or liquid to be input independently without the need for external valve group to switch the medium path. This solves the problem of system bloat caused by traditional parallel connection of multiple oil cylinders and eliminates the response lag caused by switching valve group. It realizes multi-functional integration, compact space, and improves the efficiency of industrial equipment under complex working conditions.

[0008] Optionally, the guide rod includes an inner tube, an outer tube sleeved outside the inner tube, and a drain support rod inserted into one end of the outer tube near the piston structure; The injection channel is located inside the drainage support rod, and the injection hole is connected to the inner tube.

[0009] By adopting the above technical solutions, the injection process becomes smoother and more stable. At the same time, the space layout of the inner and outer tubes is rationally utilized, improving the space utilization rate of the composite cylinder and reducing the system bloat caused by unreasonable injection structure. The liquid can flow into the inner tube through the injection hole and then be discharged through the injection channel in the drain support rod, optimizing the delivery path of the injection medium and facilitating the composite cylinder to achieve the water injection function.

[0010] Optionally, an air intake chamber is formed between the outer wall of the inner tube and the inner wall of the outer tube, the air injection channel is located inside the exhaust support rod, and the air intake chamber is connected to the air injection channel; The cylinder body is provided with an air guide ring cavity, which surrounds the outer tube. The air injection hole is connected to the air guide ring cavity, and the air intake cavity is also connected to the air guide ring cavity.

[0011] By adopting the above technical solution, the air inlet cavity formed between the outer wall of the inner tube and the inner wall of the outer tube, as well as the air injection channel in the exhaust support rod, allows the gas to enter the air guide ring cavity through the air injection hole and then flow into the air injection channel through the air inlet cavity, thus optimizing the air injection path and ensuring smooth air injection.

[0012] Optionally, the cylinder body includes a cylinder liner and a cylinder head, the piston movement chamber is located inside the cylinder head, one end of the cylinder head is provided with a connecting shaft, and one end of the connecting shaft passes through the cylinder liner and is rotatably connected to the cylinder liner. The guide rod passes through the connecting shaft and is fixedly connected to the connecting shaft. The connecting shaft is provided with a first oil inlet channel, one end of which is connected to the piston movement chamber, and the first oil inlet channel is also connected to the first oil supply hole.

[0013] By adopting the above technical solution, the cylinder head can rotate relative to the cylinder liner, which increases the flexibility of the composite cylinder. The rotating structure supports multi-dimensional motion requirements and reduces the mechanical constraints of traditional fixed cylinders. The guide rod is fixed with the connecting shaft, which can ensure the stability of the air injection channel and the liquid injection channel. The first oil inlet channel connects the first oil supply hole with the piston movement chamber, which can better drive the piston movement.

[0014] Optionally, the connecting shaft is further provided with a second oil inlet channel, and the second oil supply hole is connected to the second oil inlet channel; The cylinder head is provided with a steering oil inlet channel. One end of the second oil inlet channel is connected to the steering oil inlet channel, and one end of the steering oil inlet channel is connected to the end of the piston movement chamber away from the first oil inlet channel.

[0015] By adopting the above technical solution, the second oil supply hole is connected to the second oil inlet channel, and the steering oil inlet channel connects the second oil inlet channel to the other end of the piston movement chamber; during operation, hydraulic oil enters the steering oil inlet channel through the second oil supply hole, driving the piston to move in the opposite direction, thereby realizing the normal operation of the composite cylinder.

[0016] Optionally, the steering oil inlet channel includes a radial oil passage and a steering oil passage, and the radial oil passage is connected between the second oil inlet channel and the steering oil passage; The radial oil passage extends through the cylinder head at one end near the steering oil passage and is detachably connected to a sealing plug.

[0017] By adopting the above technical solution, the steering oil inlet channel is configured as a radial oil passage and a steering oil passage. The radial oil passage connects the second oil inlet channel and the steering oil passage, allowing the oil to flow orderly to the corresponding position in the piston movement chamber, ensuring the normal operation of the composite cylinder. The end of the radial oil passage near the steering oil passage passes through the cylinder head and connects to a sealing plug. Passing through the cylinder head facilitates installation and maintenance, and allows the sealing plug to be opened for direct inspection of the oil condition in the radial oil passage and for any blockages or other faults, improving maintenance convenience. The sealing plug serves a sealing function, preventing oil leakage in the second oil inlet channel, ensuring stable oil pressure, and guaranteeing the working performance of the composite cylinder.

[0018] Optionally, a buffer groove is provided in the cylinder body, the buffer groove is located between the injection hole and the guide rod, and a buffer ring is slidably disposed in the buffer groove; The buffer ring is fitted with a sealing ring, and the cylinder body is also provided with a force-applying component for driving the buffer ring to press against the guide rod; A drain hole is provided on the outer wall of the cylinder, and the drain hole is connected to one end of the buffer groove near the guide rod.

[0019] By adopting the above technical solution, the problems of pressure shock and leakage under injection conditions are solved. During operation, the buffer ring absorbs injection pressure fluctuations, and leaked liquid is discharged through the drain hole. When high-pressure liquid enters from the injection hole, the impact force pushes the buffer ring to slide within the buffer groove, and the sealing ring on the outside of the buffer ring immediately and tightly adheres to the outer wall of the guide rod to form an initial seal. The force spring continuously provides axial thrust to ensure that the buffer ring always presses against the guide rod, forming a dynamic self-compensating seal. If the injection pressure increases suddenly, the high-pressure liquid seeps into the rear space of the buffer groove through the gap between the buffer ring and the groove wall, pushing the buffer ring to compress and move towards the force spring. At this time, the drain hole, which was originally closed by the buffer ring, is exposed, and the high-pressure liquid is discharged from the system through the drain hole, realizing pressure release.

[0020] Optionally, the force-applying component includes a force-applying spring disposed between the inner bottom wall of the buffer groove and the buffer ring.

[0021] By adopting the above technical solution, the dynamic performance of the sealing compensation is improved. The force-applying component is specifically defined as the force-applying spring installed in the buffer groove, which pushes the buffer ring to continuously press against the guide rod. During the operation, the spring provides a constant preload, and the buffer ring automatically adapts to wear or thermal expansion.

[0022] Optionally, the piston structure includes a piston sleeve and a piston ring fitted and fixed outside the piston sleeve. The piston ring slides within the piston movement chamber, and the piston sleeve is fitted outside the guide rod.

[0023] By adopting the above technical solution, the piston sleeve is sleeved outside the guide rod, and the piston ring is fixed outside the sleeve; a piston movement chamber is provided in the cylinder body, and the piston ring can slide in the piston movement chamber. By using the first oil supply hole to connect with one end of the piston movement chamber and the second oil supply hole to connect with the other end of the piston movement chamber, the linear reciprocating motion drive of the piston structure can be realized.

[0024] Optionally, an oil unloading chamber is provided inside the cylinder liner, and one end of the first oil inlet channel and the second channel are both connected to the oil unloading chamber, and an oil seal is provided at the connecting end of the first oil inlet channel and the second oil inlet channel to the oil unloading chamber. An oil unloading hole is provided on the outer wall of the cylinder body, and an oil unloading channel is provided inside the cylinder body. One end of the oil unloading channel is connected to the oil unloading chamber, and the other end of the oil unloading channel is connected to the oil unloading hole.

[0025] By adopting the above technical solution, the leaked oil in the first and second oil inlet channels is collected by the unloading chamber. When the oil pressure is too high, the oil seal at the end of the first or second oil inlet channel that connects to the unloading chamber fails, allowing the excess oil to be discharged into the unloading chamber and then discharged from the unloading hole on the outer wall of the cylinder through the unloading channel. This automatic pressure relief reduces the risk of system overload, maintains oil pressure stability, and avoids damage to the cylinder due to excessive oil pressure, thereby improving the safety and reliability of the composite cylinder.

[0026] In summary, this application includes at least one of the following beneficial effects: 1. In this application, by setting a piston movement chamber in the cylinder body and setting a first oil inlet hole, a second oil inlet hole, an air injection hole and a liquid injection hole on the outer wall of the cylinder body, and cooperating with the air injection channel and liquid injection channel in the guide rod, the water injection and air injection functions can be effectively realized, avoiding the use of multiple independent oil cylinders in parallel, making the overall structure more compact, greatly reducing space occupation, and significantly reducing weight and cost; 2. The guide rod in this application adopts a structural design of inner tube, outer tube and drain support rod, so that the liquid injection channel and air injection channel are reasonably distributed, realizing the isolated delivery of different media, optimizing the media delivery path, ensuring the smoothness and stability of the water injection and air injection process, which helps to improve the working accuracy and performance of the composite cylinder and meet the needs of more complex working conditions. 3. This application integrates water injection and air injection functions, eliminating the need for a large number of additional liquid supply pipelines within the system. This greatly improves the compactness of the system structure, simplifies the overall layout of the system, reduces potential faults caused by complex pipelines, and helps improve the system's maintenance convenience and stability. Attached Figure Description

[0027] Figure 1 This is an embodiment of the integral structure of a composite hydraulic cylinder according to this application. Schematic diagram; Figure 2 This is a cross-sectional structural schematic diagram of a composite hydraulic cylinder according to an embodiment of this application; Figure 3 This is a cross-sectional structural schematic diagram of a composite hydraulic cylinder according to an embodiment of this application from another perspective; Explanation of reference numerals in the attached drawings: 1. Cylinder block; 11. Cylinder head; 111. Piston movement chamber; 112. Steering oil inlet passage; 1121. Radial oil passage; 1122. Steering oil passage; 113. Buffer groove; 12. Cylinder liner; 121. First oil inlet hole; 122. Second oil inlet hole; 123. Air inlet hole; 124. Fluid inlet hole; 125. Air guide ring chamber; 126. Drain hole; 127. Oil discharge chamber; 128. Oil discharge hole; 129. Oil unloading channel; 13. Connecting shaft; 131. First oil inlet channel; 132. Second oil inlet channel; 2. Guide rod; 21. Inner tube; 22. Outer tube; 23. Drain support rod; 231. Air injection channel; 232. Liquid injection channel; 24. Air inlet chamber; 3. Piston structure; 31. Piston sleeve; 32. Piston ring; 4. Sealing plug; 5. Buffer ring; 6. Sealing ring; 7. Force spring; 8. Oil seal. Detailed Implementation

[0028] The following is in conjunction with the appendix Figure 1 -Appendix Figure 3 This application will be described in further detail.

[0029] Embodiment 1 of this application provides a composite hydraulic cylinder.

[0030] refer to Figure 1 and Figure 2 The composite hydraulic cylinder with water injection and air injection functions provided in this application embodiment includes a cylinder body 1, a guide rod 2, and a piston structure 3. The cylinder body 1, the guide rod 2, and the piston structure 3 cooperate with each other. The guide rod 2 and the piston structure 3 are disposed on the cylinder body 1. The piston structure 3 is sleeved outside the guide rod 2 and can slide within the piston movement chamber 111 of the cylinder body 1. This achieves the simultaneous realization of water injection and air injection functions, avoiding the problems of bloated structure and delayed response of switching valve group caused by multiple independent hydraulic cylinders connected in parallel in the traditional solution.

[0031] refer to Figure 2 The cylinder body 1 includes a cylinder liner 12 and a cylinder head 11. The cylinder head 11 includes a cylinder shell with one open end and a cylinder cover that is sealed and snapped into the opening of the cylinder shell. The cylinder shell and the cylinder cover are fixedly connected by bolts, and a piston movement chamber 111 is formed between the inner wall of the cylinder shell and the cylinder cover. A connecting shaft 13 is integrally formed at the end of the cylinder cover away from the cylinder shell. One end of the connecting shaft 13 passes through the cylinder liner 12, and the connecting shaft 13 is rotatably connected to the cylinder liner 12 through a bearing to ensure stable rotation of the connecting shaft 13. In this embodiment, both the cylinder liner 12 and the cylinder head 11 are cylindrical and coaxially arranged. The cylinder liner 12 can be made of a high-strength metal material, such as alloy steel, to ensure that it can withstand greater pressure.

[0032] refer to Figure 2The piston structure 3 includes a piston sleeve 31 and a piston ring 32 fixedly fitted outside the piston sleeve 31. The piston ring 32 slides within the piston movement chamber 111, and one end of the piston sleeve 31 is located outside the piston movement chamber 111. During operation, the workpiece or working component is directly threaded or snapped onto one end of the piston sleeve 31. The piston sleeve 31 can be made of aluminum alloy, and the piston ring 32 can be made of cast iron, providing good wear resistance and sealing performance. A sealing rubber ring is also fixedly fitted outside the piston ring 32. When the piston ring 32 slides within the piston movement chamber 111, the sealing rubber ring tightly adheres to the inner wall of the piston movement chamber 111, preventing oil leakage and simultaneously enabling the linear reciprocating motion of the piston structure 3, thereby driving the connected components to complete the corresponding work.

[0033] refer to Figure 2 and Figure 3 The cylinder liner 12 has a first oil inlet hole 121 and a second oil inlet hole 122 spaced apart on its outer side wall. A first oil inlet channel 131 is axially formed inside the connecting shaft 13, with one end extending to the cylinder head 11 and communicating with one end of the piston movement chamber 111. A first annular cavity is formed on the inner side wall of the cylinder liner 12. A first through hole is formed on the inner side wall of the first oil inlet channel 131 located inside the first annular cavity. One end of the first oil inlet hole 121 communicates with the first annular cavity, allowing indirect communication between the first oil inlet channel 131 and the first oil inlet hole 121. Oil input through the first oil inlet hole 121 can flow along the first annular cavity into the first oil inlet channel 131, and then into one end of the piston movement chamber 111, driving the piston structure 3 to move. Multiple first oil inlet channels 131 are spaced apart around the axis of the connecting shaft 13, and correspondingly, multiple first through holes are also formed. In this embodiment, two first oil inlet channels 131 and two first through holes are provided.

[0034] refer to Figure 3A second oil inlet channel 132 is axially formed inside the connecting shaft 13, with one end extending into the cylinder head 11. A second annular cavity is formed on the inner sidewall of the cylinder liner 12, and a second through hole is formed on the inner sidewall of the second oil inlet channel 132 located inside the second annular cavity. One end of the second oil supply hole 122 communicates with the second annular cavity, allowing the second annular cavity to indirectly connect the second oil inlet channel 132 and the second oil supply hole 122. A steering oil inlet channel 112 is formed inside the cylinder head 11, which includes a radial oil passage 1121 and a steering oil passage 1122 that are interconnected. The radial oil passage 1121, near the steering oil passage 1122, passes through the cylinder head 11 and is connected to a sealing plug 4, which prevents oil leakage. In this embodiment, the sealing plug 4 is specifically a plug screw, and the sealing plug 4 is threaded to one end of the radial oil passage 1121. One end of the second oil inlet channel 132 is connected to the radial oil passage 1121, and the end of the steering oil passage 1122 away from the radial oil passage 1121 is connected to the end of the piston movement chamber 111 away from the first oil inlet channel 131. Oil input through the second oil inlet hole 122 can sequentially enter the second oil inlet channel 132 and the steering oil inlet channel 112 through the second annular cavity, and finally flow into the other end of the piston movement chamber 111, realizing the reverse movement of the piston structure 3. Multiple second oil inlet channels 132 are spaced apart around the axis of the connecting shaft 13; correspondingly, multiple second through holes and steering oil inlet channels 112 are also provided. In this embodiment, two of each of the second oil inlet channel 132, second through holes, and steering oil inlet channels 112 are provided.

[0035] refer to Figure 2 and Figure 3 An oil unloading chamber 127 is provided inside the cylinder liner 12, located at the end of the connecting shaft 13 away from the cylinder head 11. The ends of the first oil inlet channel 131 and the second oil inlet channel 132 near the oil unloading chamber 127 are both connected to the oil unloading chamber 127, and an oil seal 8 is provided at the connecting ends of the first oil inlet channel 131 and the second oil inlet channel 132 and the oil unloading chamber 127. In this embodiment, the oil seal 8 is specifically a cylindrical body made of rubber, and one end of the oil seal 8 is tapered, forming a cone shape. An oil unloading hole 128 is provided on the outer wall of the cylinder body 1, and an oil unloading channel 129 is provided inside the cylinder body 1. One end of the oil unloading channel 129 is connected to the oil unloading chamber 127, and the other end of the oil unloading channel 129 is connected to the oil unloading hole 128. Oil leaking into the oil unloading chamber 127 can be discharged through the oil unloading hole 128.

[0036] refer to Figure 2 and Figure 3The guide rod 2 includes an inner tube 21, an outer tube 22 sleeved outside the inner tube 21, and a drain support rod 23. One end of the outer tube 22 passes through the cylinder liner 12, and the other end is located inside the cylinder head 11. The length of the inner tube 21 is slightly shorter than that of the outer tube 22. The drain support rod 23 is tightly inserted into the end of the outer tube 22 near the piston structure 3. The drain support rod 23 is cylindrical, and an injection channel 231 and a liquid injection channel 232 are opened along its own axis. In this embodiment, the liquid injection channel 232 is coaxial with the axis of the drain support rod 23, and the injection channel 231 is parallel to the liquid injection channel 232. An injection hole 124 is opened at the end of the cylinder liner 12 away from the cylinder head 11, and the axis of the injection hole 124 is coaxial with the axis of the inner tube 21. One end of the inner tube 21 is inserted into the liquid injection channel 232 and fixed to the inner sidewall of the liquid injection channel 232. The injection hole 124 is connected to the inner tube 21 so that the liquid injected through the injection hole 124 enters the inner tube 21 and is discharged to the required working position through the injection channel 232 of the drain support rod 23. When the piston sleeve 31 is fitted outside the drain support rod 23, a sealing ring is provided at the end of the piston sleeve 31 away from the piston ring 32. The sealing ring is engaged with the inner side of the piston sleeve 31 to prevent liquid and gas from entering. When a workpiece or working part is connected to one end of the piston sleeve 31, the liquid passage of the connected workpiece or working part needs to be connected to the injection channel 232, and the gas passage of the connected workpiece or working part needs to be connected to the gas injection channel 231.

[0037] refer to Figure 2 and Figure 3 The cylinder liner 12 also has a buffer groove 113 located between the injection hole 124 and the inner tube 21. A buffer ring 5 is slidably disposed within the buffer groove 113, and a sealing ring 6 is fitted over the buffer ring 5. The sealing ring 6 is embedded and fixed within the inner wall of the buffer groove 113. The sealing ring 6 is generally made of rubber and serves to seal and prevent liquid leakage. A force-applying component is also provided within the buffer groove 113, specifically a force-applying spring 7 connecting the inner wall of the buffer groove 113 and the buffer ring 5. In this embodiment, the buffer ring 5 is made of a wear-resistant material, such as ceramic, which reduces wear between it and the guide rod 2 and extends its service life. In other embodiments, the force-applying component may also be a short rubber tube.

[0038] refer to Figure 2 A drain hole 126 is provided on the outer wall of the cylinder liner 12. The drain hole 126 is connected to one end of the buffer slide 113 near the guide rod 2. When liquid leaks into the buffer slide 113, the leaked liquid can be discharged through the drain hole 126.

[0039] refer to Figure 2 and Figure 3An annular air intake chamber 24 is formed between the outer wall of the inner tube 21 and the inner wall of the outer tube 22, and the air intake chamber 24 is connected to the air injection channel 231 in the exhaust support rod 23. A guide ring cavity 125 is provided inside the cylinder liner 12, surrounding the outer tube 22, and the air injection hole 123 is connected to the guide ring cavity 125. A third through hole is provided on the inner wall of the air intake chamber 24, located inside the guide ring cavity 125, connecting the air intake chamber 24 to the guide ring cavity 125. Gas introduced through the air injection hole 123 can enter the air intake chamber 24 along the guide ring cavity 125, then flow to the air injection channel 231 and be discharged to a designated location. This allows for both basic expansion and contraction functions, as well as the detection of workpiece airtightness, gas supply during processing, or impurity purging. The guide rod 2 effectively realizes water and air injection functions, accurately delivering different media to designated locations.

[0040] The implementation principle of a composite hydraulic cylinder in this embodiment is as follows: the composite hydraulic cylinder integrates water injection and air injection functions through a reasonable design of the cylinder body 1, guide rod 2, and piston structure 3. Hydraulic oil enters the piston motion chamber 111 through the first oil inlet 121 and the second oil inlet 122, driving the piston structure 3 to perform linear reciprocating motion. External gas is injected through the air injection port 123 and then discharged sequentially through the air guide ring chamber 125, the air inlet chamber 24, and the air injection channel 231; external liquid is injected through the liquid injection port 124 and then discharged sequentially through the inner pipe 21 and the liquid injection channel 232, thus realizing the multi-media transportation function. Compared with the traditional scheme of multiple independent hydraulic cylinders and switching valve groups in parallel, the composite hydraulic cylinder in this embodiment has a more compact structure, saving space and cost, and does not have the problem of response lag.

[0041] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A composite cylinder, characterized by include: A cylinder body (1) is provided with a piston movement chamber (111) inside the cylinder body (1). A first oil inlet hole (121), a second oil inlet hole (122), an air injection hole (123) and a liquid injection hole (124) are provided on the outer side wall of the cylinder body (1). The first oil inlet hole (121) is connected to one end of the piston movement chamber (111), and the second oil inlet hole (122) is connected to the other end of the piston movement chamber (111). A guide rod (2) is inserted into the cylinder body (1) at one end. The guide rod (2) is provided with an air injection channel (231) and a liquid injection channel (232) that are connected to the outside. The air injection hole (123) is connected to the air injection channel (231), and the liquid injection hole (124) is connected to the liquid injection channel (232). Piston structure (3), one end of which is slidably disposed in the piston movement chamber (111), and the other end is located outside the cylinder body (1); The cylinder body (1) is provided with a buffer groove (113), which is located between the injection hole (124) and the guide rod (2). A buffer ring (5) is slidably provided in the buffer groove (113). The buffer ring (5) is fitted with a sealing ring (6), and the cylinder body (1) is also provided with a force-applying component for driving the buffer ring (5) to press against the guide rod (2); A drain hole (126) is provided on the outer side wall of the cylinder (1), and the drain hole (126) is connected to one end of the buffer slide (113) near the guide rod (2); The force-applying component includes a force-applying spring (7) disposed between the inner bottom wall of the buffer groove (113) and the buffer ring (5).

2. The composite cylinder according to claim 1, wherein: The guide rod (2) includes an inner tube (21), an outer tube (22) sleeved outside the inner tube (21), and a drain support rod (23) inserted into one end of the outer tube (22) near the piston structure (3). The injection channel (232) is located inside the drain support rod (23), and the injection hole (124) is connected to the inner tube (21).

3. A composite hydraulic cylinder according to claim 2, characterized in that: An air inlet chamber (24) is formed between the outer wall of the inner tube (21) and the inner wall of the outer tube (22). The air injection channel (231) is located inside the drain support rod (23). The air inlet chamber (24) is connected to the air injection channel (231). The cylinder body (1) is provided with an air guide ring cavity (125), which surrounds the outer tube (22). The air injection hole (123) is connected to the air guide ring cavity (125), and the air intake cavity (24) is also connected to the air guide ring cavity (125).

4. A composite hydraulic cylinder according to claim 1, characterized in that: The cylinder body (1) includes a cylinder liner (12) and a cylinder head (11). The piston movement chamber (111) is located inside the cylinder head (11). A connecting shaft (13) is provided at one end of the cylinder head (11). One end of the connecting shaft (13) passes through the cylinder liner (12) and is rotatably connected to the cylinder liner (12). The guide rod (2) passes through the connecting shaft (13) and is fixedly connected to the connecting shaft (13); The connecting shaft (13) is provided with a first oil inlet channel (131), one end of the first oil inlet channel (131) is connected to the piston motion chamber (111), and the first oil inlet channel (131) is also connected to the first oil supply hole (121).

5. A composite hydraulic cylinder according to claim 4, characterized in that: The connecting shaft (13) is also provided with a second oil inlet channel (132), and the second oil supply hole (122) is connected to the second oil inlet channel (132); The cylinder head (11) is provided with a steering oil inlet channel (112), one end of the second oil inlet channel (132) is connected to the steering oil inlet channel (112), and one end of the steering oil inlet channel (112) is connected to the end of the piston movement chamber (111) away from the first oil inlet channel (131).

6. A composite hydraulic cylinder according to claim 5, characterized in that: The steering oil inlet channel (112) includes a radial oil passage (1121) and a steering oil passage (1122), and the radial oil passage (1121) is connected between the second oil inlet channel (132) and the steering oil passage (1122); The radial oil passage (1121) passes through the cylinder head (11) at one end near the steering oil passage (1122) and is connected to a sealing plug (4) by means of disassembly.

7. A composite hydraulic cylinder according to claim 1, characterized in that: The piston structure (3) includes a piston sleeve (31) and a piston ring (32) sleeved and fixed outside the piston sleeve (31). The piston ring (32) slides inside the piston movement chamber (111), and the piston sleeve (31) is sleeved outside the guide rod (2).

8. A composite hydraulic cylinder according to claim 5, characterized in that: The cylinder liner (12) has an oil unloading chamber (127) inside. One end of the first oil inlet channel (131) and the second oil inlet channel (132) are connected to the oil unloading chamber (127), and oil seals (8) are provided at the connecting ends of the first oil inlet channel (131) and the second oil inlet channel (132) and the oil unloading chamber (127). An oil unloading hole (128) is provided on the outer side wall of the cylinder (1), and an oil unloading channel (129) is provided inside the cylinder (1). One end of the oil unloading channel (129) is connected to the oil unloading chamber (127), and the other end of the oil unloading channel (129) is connected to the oil unloading hole (128).

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