Double-chamber hydraulic cylinder

Abstract

The utility model discloses a double-chamber hydraulic cylinder which comprises a cylinder body and a piston. The cylinder body comprises a front end face and a rear end face. A cavity and a guide hole are formed in the cylinder body, and a limiting end wall is formed on the inner surface of the cylinder body; the piston comprises a piston disc and a piston rod, the piston disc divides the cavity into a first cavity and a second cavity, a communicating cavity is formed between the peripheral face of the piston rod and the inner wall of the guide hole, a through hole is formed in the piston rod, a first opening is formed in one end of the through hole, and a second opening is formed in the other end of the through hole. The first opening and the second opening are staggered in the axial direction of the piston rod, so that when the piston disc is located at the position attached to the limiting end wall, the communicating cavity communicates with the first cavity through the communicating hole. The maximum stroke of the piston disc moving in the cavity of the cylinder body is increased, the external size of the hydraulic cylinder does not need to be increased, and meanwhile the efficiency of the hydraulic cylinder is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of hydraulic cylinders, in particular to a double-chamber hydraulic cylinder. Background Art

[0002] A hydraulic cylinder usually includes a cylinder body and a piston rod. The part of the piston rod extending into the cylinder body is equipped with a piston. The piston is tightly fitted with the inner wall of the cylinder body. After the piston is placed in the cylinder body, the interior of the cylinder body is divided into two chambers. Each chamber is connected to the hydraulic circuit through a connecting hole on the side wall of the cylinder body. The opening of the connecting hole on the inner surface of the chamber is set on the side of the cylinder body. When the piston moves back and forth to the extreme position, the piston will block the opening of the connecting hole on the inner surface of the chamber, making it difficult for the piston to move to the front and rear ends of the cylinder body, resulting in a relatively limited stroke of the piston moving back and forth in the cylinder body. In order to meet the requirements of use for the stroke of the piston moving back and forth, it is necessary to increase the length of the cylinder body. This is obviously not conducive to controlling the external dimensions of the cylinder body, resulting in the hydraulic cylinder having relatively large external dimensions. Utility Model Content

[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model aims to provide a double-chamber hydraulic cylinder, which can make the piston have a relatively large stroke without increasing the external dimensions of the hydraulic cylinder.

[0004] The purpose of the utility model is achieved by the following technical solutions:

[0005] The first aspect of the utility model provides a double-chamber hydraulic cylinder, comprising:

[0006] Cylinder, piston;

[0007] The cylinder body comprises a front end face and a rear end face opposite to the front end face; a cavity and a guide hole are arranged inside the cylinder body, a limiting end wall located at the front end of the cavity is formed on the inner surface of the cylinder body, and the guide hole extends from the limiting end wall to the front end face of the cylinder body;

[0008] The piston comprises a piston disc and a piston rod connected to the piston disc, the piston disc is placed in the cavity to divide the cavity into a first chamber and a second chamber, the piston rod is inserted into the guide hole and tightly matched with the inner wall of the guide hole, a connecting cavity is formed between the outer circumference of the piston rod and the inner wall of the guide hole, a conducting hole is arranged inside the piston rod, one end of the conducting hole extends to the outer circumference of the piston rod to form a first opening, and the other end extends to the surface of the junction between the piston rod and the piston disc to form a second opening, the first opening and the second opening are staggered with each other in the axial direction of the piston rod, so that when the piston disc is located at a position close to the limit end wall, the connecting cavity and the first chamber are connected by the conducting hole;

[0009] The cylinder body is provided with a first connecting hole, a second connecting hole and a third connecting hole which are connected with the first chamber, the second chamber and the connecting cavity respectively. The outer ends of the first connecting hole, the second connecting hole and the third connecting hole extend to the outer surface of the cylinder body to form an interface.

[0010] According to the dual-chamber hydraulic cylinder of the utility model embodiment, a through hole is provided on the piston rod, so that the first opening and the second opening of the through hole are staggered with a certain distance from each other in the axial direction of the piston rod. When the piston rod is extended and retracted outward to the limit position, the piston disc abuts against the limit end wall at the front end of the cylinder cavity, the first opening of the through hole is connected with the third through hole through the connecting cavity, and the second opening of the through hole is connected with the first chamber on the front side of the piston disc. Even when the piston disc moves forward to the limit position, the hydraulic oil inside the first chamber can be discharged as much as possible through the through hole. At the same time, the piston disc will not block the second opening. When the piston disc moves backward to drive the piston rod to retract backward, the external hydraulic oil can be smoothly introduced into the first chamber through the through hole, and the piston disc can be pushed backward in time. In this way, the maximum stroke of the piston disc in the cylinder cavity is increased without increasing the external size of the hydraulic cylinder, and the efficiency of the hydraulic cylinder is increased.

[0011] In the first aspect of the utility model, as an optional embodiment, the piston disc includes a sealing flange tightly matched with the inner surface of the cavity, and a limiting disc located in front of the sealing flange, the periphery of the limiting disc is in clearance with the side wall of the cavity, the second opening is located at the position where the limiting disc and the piston rod are connected, and a connecting groove extending from the second opening to the outer periphery of the limiting disc is provided on the surface of the limiting disc facing the limiting end wall. The sealing flange on the piston disc is tightly matched with the side wall of the cavity to separate the cavity into a first chamber and a second chamber, the periphery of the limiting disc is in clearance with the side wall of the cavity, and when the piston rod retracts backward, the second opening of the conducting hole can deliver hydraulic oil into the gap between the limiting disc and the side wall of the cavity, thereby pushing the piston disc to move backward smoothly to drive the piston rod to retract backward.

[0012] In the first aspect of the utility model, as an optional embodiment, the guide hole extends from one side of the piston rod to the other side, and the extension direction of the guide hole forms an angle a with the central axis of the piston rod, wherein 35°≤a≤85°. The guide hole is set as an inclined structure so that the first opening and the second opening of the guide hole are staggered in the axial direction of the piston rod, which can facilitate the processing of the guide hole. The deflection angle of the guide hole is set within the above range so that the first opening and the second opening have a suitable staggered distance in the axial direction of the piston rod, so as to ensure a good airtight fit between the piston rod and the inner wall of the guide hole, and at the same time, the second opening can be extended to the limit plate to ensure that the second opening is connected to the first chamber.

[0013] In the first aspect of the utility model, as an optional embodiment, the piston disc is provided with an annular groove located between the sealing flange and the limiting disc and opening outward. The annular groove is provided on the piston disc, and when the piston disc abuts against the limiting end wall at the front end of the cavity, a small portion of hydraulic oil can be accommodated in the annular groove to prevent the hydraulic oil in the first chamber from being completely emptied, thereby ensuring that the piston disc can smoothly retract backward.

[0014] In the first aspect of the utility model, as an optional embodiment, an annular recessed position that is recessed outward is provided on the inner wall surface of the guide hole, and the connecting cavity is surrounded by the outer peripheral surface of the piston rod and the annular recessed position. The annular recessed position is provided on the inner wall of the guide hole, and the connecting cavity is formed by the annular recessed position and the outer peripheral surface of the piston rod, which can ensure the integrity of the piston rod shape, so that the piston rod can better cooperate with the guide hole for guidance, thereby improving the accuracy of the hydraulic cylinder.

[0015] In the first aspect of the utility model, as an optional embodiment, the outer ends of the first connecting hole, the second connecting hole and the third connecting hole are all extended to the top of the outer surface of the cylinder body to form an interface. The outer ends of the first connecting hole, the second connecting hole and the third connecting hole are used to communicate with the external hydraulic pipeline. The first connecting hole, the second connecting hole and the third connecting hole are all arranged on the top of the outer surface of the cylinder body, which can facilitate the layout and connection of the hydraulic pipeline.

[0016] In the first aspect of the utility model, as an optional embodiment, the dual-chamber hydraulic cylinder of the utility model further includes a rear cover, the rear end of the cavity extends to the rear end face of the cylinder body, and the rear cover is detachably fixed to the cylinder body and covers the rear end of the cavity. By arranging a detachable rear cover at the rear of the cylinder body, the piston can be installed into the cylinder body from the rear end face of the cylinder body, thereby facilitating the assembly and maintenance of the piston and the cylinder body.

[0017] In the first aspect of the utility model, as an optional embodiment, the rear cover includes a cover plate and a side plate located at the periphery of the cover plate, the side plate is sleeved on the outside of the cylinder body, a gap is formed between the periphery of the inner surface of the cover plate and the rear end face, and the inner end of the second communication hole extends to the rear end face to communicate with the second chamber through the gap. By extending the second communication hole to the rear end face of the cylinder body, the second communication hole is connected to the second chamber by utilizing the gap between the cover plate and the rear end face, so that the piston disc can move to the rear end of the cylinder body as much as possible when shrinking backwards, thereby increasing the maximum stroke of the piston disc moving inside the cylinder body.

[0018] In the first aspect of the utility model, as an optional embodiment, an annular avoidance groove is provided on the periphery of the inner surface of the cover plate, and the gap is formed by the bottom surface of the annular avoidance groove and the rear end surface. The annular avoidance groove is provided on the inner surface of the cover plate so that the annular avoidance groove faces the rear end surface of the cylinder body, thereby forming the above-mentioned gap, which can reduce the longitudinal size of the assembly formed by assembling the rear cover and the cylinder body while avoiding the cover plate from blocking the second connecting hole.

[0019] In the first aspect of the utility model, as an optional embodiment, the inner end of the first communication hole extends to the position where the limit end wall and the cavity side wall are connected. The first communication hole is arranged at the position where the limit end wall and the cavity side wall are connected, so that the first communication hole is connected to the front end of the first chamber as much as possible, which is conducive to discharging the hydraulic oil in the first chamber as soon as possible when the piston disc moves forward. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The drawings in the specification, which constitute a part of the present application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention.

[0021] Figure 1 This is a schematic diagram of the installation of the utility model;

[0022] Figure 2 It is a cross-sectional view of the utility model;

[0023] Figure 3 for Figure 2 Magnified view at A in the middle;

[0024] Figure 4 for Figure 1 Schematic diagram of the structure of the middle cylinder;

[0025] Figure 5 for Figure 1 Schematic diagram of the structure of the piston.

[0026] In the figure: 10, cylinder body; 101, front end face; 102, rear end face; 103, limit end wall; 11, cavity; 111, first connecting hole; 112, second connecting hole; 113, third connecting hole; 12, guide hole; 121, connecting cavity; 20, piston; 21, piston disk; 211, sealing flange; 212, limit disk; 213, annular groove; 214, connecting groove; 23, conducting hole; 231, first opening; 232, second opening; 30, rear cover; 31, cover plate; 311, annular avoidance groove; 32, side plate. DETAILED DESCRIPTION

[0027] Below, in conjunction with the accompanying drawings and specific implementation methods, the utility model is further described. It should be noted that, under the premise of no conflict, the various embodiments described below or the various technical features can be arbitrarily combined to form a new embodiment. Except for special instructions, the materials and equipment used in this embodiment can be purchased from the market. Examples of the embodiments are shown in the accompanying drawings, in which the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0028] In the description of the present application, it should be understood that the terms "upper", "lower", "front", "back", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as a limitation on the present application. In the description of the present application, "plurality" means two or more, unless otherwise precisely and specifically specified.

[0029] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, or it can be connected through an intermediary medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0030] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] Please refer to Figure 1-5 As shown, the embodiment of the utility model provides a double-chamber hydraulic cylinder, which includes:

[0032] Cylinder 10, piston 20;

[0033] The cylinder body 10 includes a front end face 101 and a rear end face 102 opposite to the front end face 101; a cavity 11 and a guide hole 12 are provided inside the cylinder body 10, and a limiting end wall 103 located at the front end of the cavity 11 is formed on the inner surface of the cylinder body 10, and the guide hole 12 extends from the limiting end wall 103 to the front end face 101 of the cylinder body 10;

[0034] The piston 20 includes a piston plate 21 and a piston rod 22 connected to the piston plate 21. The piston plate 21 is placed in the cavity 11 to divide the cavity 11 into a first chamber and a second chamber. The piston rod 22 is inserted into the guide hole 12 and tightly matched with the inner wall of the guide hole 12. A connecting cavity 121 is formed between the outer peripheral surface of the piston rod 22 and the inner wall of the guide hole 12. A through hole 23 is provided inside the piston rod 22. One end of the through hole 23 extends to the outer peripheral surface of the piston rod 22 to form a first opening 231, and the other end extends to the surface of the connection between the piston rod 22 and the piston plate 21 to form a first opening 231. The second opening 232 is formed, and the first opening 231 and the second opening 232 are staggered with each other in the axial direction of the piston rod 22, so that when the piston disc 21 is located in a position close to the limit end wall 103, the connecting cavity 121 and the first chamber are connected by the through hole 23; a sealing strip may be arranged between the piston rod 22 and the inner wall of the guide hole 12, so that the piston rod 22 and the inner wall of the guide hole 12 are tightly matched, and the sealing strip preferably adopts a sealing leather cup with an opening toward the cavity 11, and two sealing leather cups are arranged between the piston rod 22 and the inner wall of the guide hole 12, which are respectively located on both sides of the connecting cavity 121, so as to achieve the sealing of the connecting cavity 121.

[0035] The cylinder body 10 is provided with a first connecting hole 111, a second connecting hole 112, and a third connecting hole 113 which are connected to the first chamber, the second chamber, and the connecting cavity 121 respectively. The outer ends of the first connecting hole 111, the second connecting hole 112, and the third connecting hole 113 extend to the outer surface of the cylinder body 10 to form an interface.

[0036] According to the double-chamber hydraulic cylinder of the embodiment of the utility model, a through hole 23 is provided on the piston rod 22, so that the first opening 231 and the second opening 232 of the through hole 23 are staggered at a certain distance from each other in the axial direction of the piston rod 22. When the piston rod 22 is extended and retracted outward to the limit position, the piston disc 21 abuts against the limit end wall 103 at the front end of the cavity 11 of the cylinder body 10, and the first opening 231 of the through hole 23 is connected to the third through hole 113 through the connecting cavity 121, and the second opening 232 of the through hole 23 is connected to the first chamber on the front side of the piston disc 21, and the piston rod 22 is retracted and retracted outward to the limit position. Even when the piston disc 21 moves forward to the extreme position, the hydraulic oil inside the first chamber can be discharged as much as possible through the conducting hole 23. At the same time, the piston disc 21 will not block the second opening 232. When the piston disc 21 moves backward and drives the piston rod 22 to retract backward, the external hydraulic oil can be smoothly introduced into the first chamber through the conducting hole 23, and the piston disc 21 can be pushed backward in time. In this way, the maximum stroke of the piston disc 21 in the cavity 11 of the cylinder body 10 is increased without increasing the external size of the hydraulic cylinder, and the efficiency of the hydraulic cylinder is increased at the same time.

[0037] In a preferred embodiment of the utility model, the piston disc 21 includes a sealing flange 211 that is tightly matched with the inner surface of the cavity 11, and a limiting disc 212 located in front of the sealing flange, the periphery of the limiting disc 212 is in gap match with the side wall of the cavity 11, the second opening 232 is located at the position where the limiting disc 212 and the piston rod 22 are connected, and a connecting groove 214 extending from the second opening 232 to the outer periphery of the limiting disc 212 is provided on the surface of the limiting disc 212 facing the limiting end wall 103. The outer periphery of the sealing flange 211 and the inner surface of the cavity 11 are sealed by an O-ring. The sealing flange 211 on the piston disc 21 is tightly matched with the side wall of the cavity 11 to separate the cavity 11 into a first chamber and a second chamber. The periphery of the limit disc 212 is matched with the gap of the side wall of the cavity. When the piston rod 22 retracts backward, the hydraulic oil can be delivered into the gap between the limit disc 212 and the side wall of the cavity 11 through the second opening 232 of the through hole 23, thereby pushing the piston disc 21 to move backward smoothly to drive the piston rod 22 to retract backward.

[0038] In a preferred embodiment of the utility model, the guide hole 23 extends from one side of the piston rod 22 to the other side, and the extension direction of the guide hole 23 forms an angle a with the central axis of the piston rod 22, wherein 35°≤a≤85°. The guide hole 23 is set to an inclined structure so that the first opening 231 and the second opening 232 of the guide hole 23 are staggered in the axial direction of the piston rod 22, which can facilitate the processing of the guide hole 23. The deflection angle of the guide hole 23 is set within the above range so that the first opening 231 and the second opening 232 have a suitable staggered distance in the axial direction of the piston rod 22, so as to ensure a good airtight fit between the piston rod 22 and the inner wall of the guide hole 12, and at the same time, the second opening 232 can be extended to the limit plate 212 to ensure that the second opening 232 is connected to the first chamber.

[0039] In a preferred embodiment of the utility model, the piston disc 21 is provided with an annular groove 213 located between the sealing flange 211 and the limiting disc 212 and opening outward. The annular groove 213 is provided on the piston disc 21. When the piston disc 21 abuts against the limiting end wall 103 at the front end of the cavity 11, a small portion of hydraulic oil can be accommodated in the annular groove 213 to prevent the hydraulic oil in the first chamber from being completely emptied, thereby ensuring that the piston disc 21 can smoothly retract backward.

[0040] In a preferred embodiment of the utility model, an annular recessed position that is recessed outward is provided on the inner wall surface of the guide hole 12, and the communication cavity 121 is surrounded by the outer peripheral surface of the piston rod 22 and the annular recessed position. The annular recessed position is provided on the inner wall of the guide hole 12, and the communication cavity is formed by the annular recessed position and the outer peripheral surface of the piston rod 22, which can ensure the integrity of the outer shape of the piston rod 22, so that the piston rod 22 can be better coordinated with the guide hole 12 for guidance, thereby improving the accuracy of the hydraulic cylinder.

[0041] In a preferred embodiment of the present utility model, the outer ends of the first communication hole 111, the second communication hole 112 and the third communication hole 113 are extended to the top of the outer surface of the cylinder body 10 to form an interface. The outer ends of the first communication hole 111, the second communication hole 112 and the third communication hole 113 are used to communicate with the external hydraulic pipeline. The first communication hole 111, the second communication hole 112 and the third communication hole 113 are all arranged on the top of the outer surface of the cylinder body, which can facilitate the layout and connection of the hydraulic pipeline.

[0042] In a preferred embodiment of the utility model, the dual-chamber hydraulic cylinder of the utility model further includes a rear cover 30, the rear end of the cavity 11 extends to the rear end face 102 of the cylinder body 10, and the rear cover 30 is detachably fixed to the cylinder body 10 and covers the rear end of the cavity 11. By providing a detachable rear cover 30 at the rear of the cylinder body 10, the piston 20 can be installed into the cylinder body 10 from the rear end face of the cylinder body, thereby facilitating the assembly and maintenance of the piston 20 and the cylinder body 10.

[0043] In a preferred embodiment of the utility model, the rear cover 30 includes a cover plate 31 and a side plate 32 located at the periphery of the cover plate 31, the side plate 32 is sleeved on the outside of the cylinder body 10, a gap is formed between the periphery of the inner surface of the cover plate 31 and the rear end face 103, and the inner side end of the second communication hole 112 extends to the rear end face 103 to communicate with the second chamber through the gap. By extending the second communication hole 112 to the rear end face 103 of the cylinder body 10, the second communication hole 112 is connected with the second chamber by utilizing the gap between the cover plate 31 and the rear end face 103, so that the piston disc 21 can move to the rear end of the cylinder body 10 as much as possible when shrinking backwards, thereby increasing the maximum stroke of the piston disc 21 moving inside the cylinder body.

[0044] In a preferred embodiment of the present utility model, an annular avoidance groove 311 is provided on the periphery of the inner surface of the cover plate 31, and the gap is formed by the bottom surface of the annular avoidance groove 311 and the rear end surface 103. The annular avoidance groove 311 is provided on the inner surface of the cover plate 31, so that the annular avoidance groove 311 faces the rear end surface 103 of the cylinder body 10, thereby forming the above-mentioned gap, which can reduce the longitudinal size of the assembly formed by the rear cover 30 and the cylinder body 10 after being assembled on the basis of avoiding the cover plate 31 from blocking the second communication hole 112.

[0045] In a preferred embodiment of the present invention, the inner end of the first communication hole 111 extends to the position where the limiting end wall 103 is connected to the side wall of the cavity 11. The first communication hole 111 is arranged at the position where the limiting end wall 103 is connected to the side wall of the cavity 11, so that the first communication hole 111 is connected to the front end of the first chamber as much as possible, which is conducive to discharging the hydraulic oil in the first chamber as soon as possible when the piston plate 21 moves forward.

[0046] Although only certain components and embodiments of the present application have been illustrated and described, many modifications and changes may be conceived by those skilled in the art without actually departing from the scope and spirit of the claims, such as changes in the size, dimensions, structure, shape and proportion of the various elements, mounting arrangements, material usage, color, orientation, etc.

[0047] The above-mentioned implementation mode is only a preferred implementation mode of the embodiment of the utility model, and cannot be used to limit the scope of protection of the embodiment of the utility model. Any non-substantial changes and replacements made by technical personnel in this field on the basis of the embodiment of the utility model shall fall within the scope of protection required by the embodiment of the utility model.

Claims

1. A double-chamber hydraulic cylinder, characterized in that: Including cylinder body and piston; The cylinder body comprises a front end face and a rear end face opposite to the front end face; a cavity and a guide hole are arranged inside the cylinder body, a limiting end wall located at the front end of the cavity is formed on the inner surface of the cylinder body, and the guide hole extends from the limiting end wall to the front end face of the cylinder body; The piston comprises a piston disc and a piston rod connected to the piston disc, the piston disc is placed in the cavity to divide the cavity into a first chamber and a second chamber, the piston rod is inserted into the guide hole and tightly matched with the inner wall of the guide hole, a connecting cavity is formed between the outer circumference of the piston rod and the inner wall of the guide hole, a conducting hole is arranged inside the piston rod, one end of the conducting hole extends to the outer circumference of the piston rod to form a first opening, and the other end extends to the surface of the junction between the piston rod and the piston disc to form a second opening, the first opening and the second opening are staggered with each other in the axial direction of the piston rod, so that when the piston disc is located at a position close to the limit end wall, the connecting cavity and the first chamber are connected by the conducting hole; The cylinder body is provided with a first connecting hole, a second connecting hole and a third connecting hole which are connected with the first chamber, the second chamber and the connecting cavity respectively. The outer ends of the first connecting hole, the second connecting hole and the third connecting hole extend to the outer surface of the cylinder body to form an interface.

2. The dual-chamber hydraulic cylinder according to claim 1, characterized in that: The piston disk includes a sealing flange that is tightly matched with the side wall of the cavity, and a limit plate located in front of the sealing flange, the periphery of the limit plate is gap-matched with the side wall of the cavity, the second opening is located at the position where the limit plate and the piston rod are connected, and a connecting groove extending from the second opening to the outer periphery of the limit plate is provided on the surface of the limit plate facing the limit end wall.

3. The dual-chamber hydraulic cylinder according to claim 2, characterized in that: The conducting hole extends from one side of the piston rod to the other side, and an angle a is formed between the extending direction of the conducting hole and the central axis of the piston rod, wherein 35°≤a≤85°.

4. The dual-chamber hydraulic cylinder according to claim 2, characterized in that: The piston disc is provided with an annular groove which is located between the sealing flange and the limiting disc and opens outward.

5. The double-chamber hydraulic cylinder according to any one of claims 1 to 4, characterized in that: An outwardly recessed annular recess is arranged on the inner wall surface of the guide hole, and the connecting cavity is surrounded by the outer peripheral surface of the piston rod and the annular recess.

6. The dual-chamber hydraulic cylinder according to claim 1, characterized in that: The outer ends of the first communicating hole, the second communicating hole and the third communicating hole all extend to the top of the outer surface of the cylinder body to form an interface.

7. The dual-chamber hydraulic cylinder according to claim 1, characterized in that: It also includes a rear cover, the rear end of the cavity extends to the rear end surface of the cylinder body, and the rear cover is detachably fixed on the cylinder body and covers the rear end of the cavity.

8. The dual-chamber hydraulic cylinder according to claim 7, characterized in that: The rear cover includes a cover plate and a side plate located at the periphery of the cover plate, the side plate is sleeved on the outside of the cylinder body, a gap is formed between the periphery of the inner surface of the cover plate and the rear end surface, and the inner end of the second connecting hole extends to the rear end surface to connect with the second chamber through the gap.

9. The dual-chamber hydraulic cylinder according to claim 8, characterized in that: An annular avoidance groove is arranged at the periphery of the inner surface of the cover plate, and the gap is formed by the bottom surface of the annular avoidance groove and the rear end surface.

10. The dual-chamber hydraulic cylinder according to claim 1, characterized in that: The inner end of the first communicating hole extends to the position where the limiting end wall is connected to the side wall of the cavity.

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