hydraulic cylinder

Abstract

The cam is secured to the inner wall of the hydraulic cylinder and is adapted to engage the piston in the camming member so that the camming member can move relative to the outer wall of the hydraulic cylinder to move relative to the piston rod.

Description

Technical Field

[0001] The present invention relates to the technical field of hydraulic equipment, in particular to a hydraulic cylinder. Background Art

[0002] In the field of hydraulic equipment, it is generally stipulated that when the hydraulic cylinder's operating speed exceeds 0.2m / s, a buffer structure must be installed to reduce the impact of the piston on the hydraulic cylinder bottom and cylinder head when it moves to both ends of the hydraulic cylinder. Sometimes, to ensure the operating experience of the equipment, especially in the field of aerial work vehicles, the hydraulic cylinders used in these vehicles are also equipped with corresponding buffer structures.

[0003] At present, there are basically two methods to achieve buffering in hydraulic cylinders: one is to control the hydraulic cylinder externally, increase the stroke sensing of the hydraulic cylinder, and reduce the operating speed of the hydraulic cylinder by controlling the hydraulic oil flow at the terminal. Its structure is relatively complex and the cost is high; the other is to design a buffer structure inside the hydraulic cylinder. Its structure is simple and compact and has a wide range of applications.

[0004] In the existing technology of setting up a buffer structure inside a hydraulic cylinder, throttling is usually achieved through the gap throttling effect, that is, throttling is achieved through the gap fit between the buffer plunger and the buffer hole, so that sufficient internal pressure is formed when the hydraulic cylinder moves near the two end points, reducing the operating speed of the hydraulic cylinder to reduce the impact. However, this buffer structure has shortcomings: it requires extremely high coaxiality and extremely small fitting clearance between the buffer plunger and the buffer hole. The buffer plunger is often set at both ends of the piston, while the buffer hole is set on the cylinder base and the guide sleeve. The cylinder base and the cylinder barrel are often welded, and the guide sleeve and the cylinder barrel are threaded. This requires extremely high coaxiality requirements for each part of the piston, guide sleeve, cylinder barrel, and cylinder base, resulting in high processing accuracy requirements. In addition, welding deformation between the cylinder base and the cylinder barrel can easily destroy this precise fit. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a hydraulic cylinder that can reduce the machining accuracy requirements of parts, thereby reducing costs.

[0006] According to some embodiments of the present invention, a hydraulic cylinder includes: a cylinder assembly, one end of the cylinder assembly is provided with a rodless chamber oil port, and the other end is provided with a guide sleeve; a piston rod, the piston rod is movably provided in the guide sleeve, and the insertion end of the piston rod is extended into the cylinder assembly, the insertion end of the piston rod is fixedly connected to a supporting member, and the side wall of the piston rod is formed with a supporting portion spaced from the supporting member, and the supporting portion is located on a side of the supporting member close to the guide sleeve; a piston assembly, the piston assembly is located in the cylinder assembly, the piston assembly includes a first piston sleeved outside the piston rod and movable along the axial direction of the piston rod, and a second piston sleeved outside the piston rod and movable along the axial direction of the piston rod, the first piston and the second piston are both confined between the supporting portion and the supporting member, and the first piston is located on a side of the second piston close to the supporting portion, a limiting portion is further provided inside the cylinder assembly, the limiting portion is located on a side of the second piston away from the first piston, and an elastic compression member is provided between the first piston and the second piston;

[0007] A buffer chamber is formed between the first piston and the second piston; the first piston is provided with a first oil passage; the second piston is provided with a second oil passage; one end of the first oil passage is communicated with the rod chamber of the cylinder assembly, the other end of the first oil passage is communicated with one end of the second oil passage, and the other end of the second oil passage is communicated with the rodless chamber of the cylinder assembly; the first piston is further provided with a third oil passage communicated with the buffer chamber, the third oil passage is sealed by the abutting portion when the first piston abuts against the abutting portion, and the third oil passage is communicated with the rod chamber of the cylinder assembly when the first piston is separated from the abutting portion;

[0008] The first piston and the second piston can move closer to or farther away from each other. Before the first piston and the second piston are pressed against each other, the other end of the first oil passage and one end of the second oil passage are both connected to the buffer chamber.

[0009] The hydraulic cylinder according to the embodiment of the present invention has at least the following beneficial effects:

[0010] The operating principle of the hydraulic cylinder of the present invention is as follows:

[0011] When hydraulic oil enters from the oil port of the rodless chamber, the hydraulic oil passes through the second oil passage of the second piston and the first oil passage of the first piston to reach the rod chamber. At this time, the hydraulic oil can also enter the buffer chamber. Under the action of the pressure of the elastic compression part and the hydraulic oil, the first piston can maintain contact with the abutment of the piston rod, and the second piston can maintain contact with the abutment. At this time, the combination formed by the first piston and the second piston and the piston rod can be pushed away from the oil port of the rodless chamber by the hydraulic oil.

[0012] When the first piston and the guide sleeve are against each other, and oil continues to flow into the rodless chamber oil port, the piston rod together with the supporting member continues to drive the second piston away from the rodless chamber oil port. Due to the obstruction of the guide sleeve, the first piston cannot continue to move away from the rodless chamber oil port, and the first piston and the second piston move relative to each other, forming a nested relationship. When the piston rod together with the supporting member continues to drive the second piston away from the rodless chamber oil port, the hydraulic oil in the buffer chamber slowly flows out through the fitting gap between the first piston and the second piston, forcing the piston rod to slow down its running speed until the second piston is against the first piston, the piston rod runs to the upper end point, and the rising buffer is completed.

[0013] When the oil port of the rodless chamber is connected to the return oil tank, the hydraulic oil pressure in the hydraulic cylinder drops and is not enough to balance the load carried by the piston rod, the piston rod begins to move toward the oil port of the rodless chamber, the second piston separates from the guide sleeve, and the hydraulic oil enters the buffer chamber through the third oil passage. Under the action of the elastic compression member, the first piston moves upward relative to the second piston until it returns to its initial state. When the assembly continues to descend until the first piston abuts against the abutment and the second piston abuts against the limiter, the limiter can limit the second piston and prevent it from continuing to descend. The first piston and the second piston move relative to each other, forming a nested relationship. When the piston rod and the abutment continue to drive the first piston to descend, the hydraulic oil in the buffer chamber can slowly flow out through the fitting clearance between the first piston and the second piston and the fitting clearance between the second piston and the piston rod, forcing the piston rod to slow down its running speed until the first piston abuts against the second piston, the piston rod runs to the lower end point, and the descent buffer is completed.

[0014] The hydraulic cylinder of the present invention has a compact structure, requiring only precise alignment between the first and second pistons, and between the second piston and the piston rod. This allows for easy control of machining accuracy, eliminating the need for precise alignment between conventional buffer plungers and welded bases, thereby reducing costs. Furthermore, the first piston floats radially within the cylinder assembly, enabling automatic centering during relative motion between the first and second pistons, reducing friction between them and ensuring a good cushioning effect and extending service life.

[0015] According to some embodiments of the present invention, a first chamber is provided on a side of the second piston close to the first piston, and the first piston can be inserted into the first chamber.

[0016] According to some embodiments of the present invention, the first piston includes a sealing portion that seals with the inner wall of the cylinder assembly, and a penetration portion connected to the sealing portion, the penetration portion can be penetrated into the first chamber, the outer side wall of the penetration portion is spaced from the inner side wall of the cylinder assembly, and the outer side wall of the penetration portion is provided with an oil groove, the oil groove is connected to the other end of the first oil channel, and the oil groove is connected to one end of the second oil channel.

[0017] According to some embodiments of the present invention, the first oil passage is opened in the sealing portion, and the other end of the first oil passage is connected to the gap between the outer wall of the penetration portion and the inner wall of the cylinder assembly.

[0018] According to some embodiments of the present invention, one end of the second oil passage is communicated with a gap between an outer side wall of the penetration portion and an inner side wall of the cylinder assembly.

[0019] According to some embodiments of the present invention, a second chamber is provided on a side of the penetration portion close to the second piston, the second chamber is communicated with the first chamber, and the third oil passage is communicated with the second chamber.

[0020] According to some embodiments of the present invention, the outer side wall of the penetration portion is guided and matched with the side wall of the first chamber.

[0021] According to some embodiments of the present invention, the elastic compression member is a spring, and the spring is sleeved outside the piston rod.

[0022] According to some embodiments of the present invention, the cylinder assembly includes a cylinder barrel and a base disposed at one end of the cylinder barrel, and the guide sleeve is disposed inside the other end of the cylinder barrel.

[0023] According to some embodiments of the present invention, one end of the third oil passage is connected to the buffer chamber, and the other end is arranged opposite to the abutting portion. When the first piston abuts against the abutting portion, the other end of the third oil passage is sealed by the abutting portion. When the first piston is separated from the abutting portion, the other end of the third oil passage is connected to the rod chamber of the cylinder assembly.

[0024] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0026] Figure 1 A schematic diagram of the structure of a hydraulic cylinder according to an embodiment of the present invention Figure 1 ;

[0027] Figure 2 A schematic diagram of the structure of a hydraulic cylinder according to an embodiment of the present invention Figure 2 ;

[0028] Figure 3 A schematic diagram of the structure of a hydraulic cylinder according to an embodiment of the present invention Figure 3 ;

[0029] Figure 4 A schematic diagram of the structure of a hydraulic cylinder according to an embodiment of the present invention Figure 4 ;

[0030] Figure 5 A schematic diagram of the structure of a hydraulic cylinder according to an embodiment of the present invention Figure 5 .

[0031] Figure Number:

[0032] 100, cylinder assembly; 101, rodless chamber oil port; 102, rodless chamber; 103, rod chamber; 104, stopper; 110, cylinder barrel; 120, base;

[0033] 200, guide sleeve;

[0034] 300, piston rod; 310, abutting member; 320, abutting portion; 330, locking member;

[0035] 400, piston assembly; 401, buffer chamber; 410, first piston; 410a, sealing portion; 410b, penetration portion; 411, first oil passage; 412, third oil passage; 413, oil groove; 414, second chamber; 420, second piston; 421, second oil passage; 422, first chamber;

[0036] 500. Elastic compression parts. DETAILED DESCRIPTION

[0037] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, features defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0039] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0040] like Figure 1 As shown, a hydraulic cylinder according to an embodiment of the present invention includes a cylinder assembly 100 , a guide sleeve 200 , a piston rod 300 and a piston assembly 400 .

[0041] A rodless chamber oil port 101 is provided at one end of the cylinder assembly 100 , and a guide sleeve 200 is provided inside the other end of the cylinder assembly 100 .

[0042] Specifically, the cylinder assembly 100 is a hollow structure, and the cylinder assembly 100 has two opposite ends. One end of the cylinder assembly 100 is provided with a rodless cavity oil port 101 connected to the interior of the cylinder assembly 100, and the other end of the cylinder assembly 100 is fixedly provided with a guide sleeve 200.

[0043] The cylinder assembly 100 includes a cylinder barrel 110 and a base 120 disposed at one end of the cylinder barrel 110 , and the rodless chamber oil port 101 is opened on the base 120 .

[0044] It should be noted that the base 120 is fixed to one end of the cylinder 110 by welding; the guide sleeve 200 is fixed to the cylinder 110 by threaded connection, that is, the outer wall of the guide sleeve 200 is provided with a first thread, and the inside of the other end of the cylinder 110 is provided with a second thread, and the guide sleeve 200 is passed through the other end of the cylinder 110 and connects the first thread with the second thread.

[0045] Of course, in other embodiments, the base 120 and the cylinder 110 may be fixedly connected in other ways, and the guide sleeve 200 may be fixed inside the cylinder 110 in other ways.

[0046] The piston rod 300 can be movably inserted into the guide sleeve 200, and the inserted end of the piston rod 300 is inserted into the cylinder assembly 100. The inserted end of the piston rod 300 is fixedly connected to a supporting member 310, and the side wall of the piston rod 300 is formed with a supporting portion 320 spaced apart from the supporting member 310. The supporting portion 320 is located on the side of the supporting member 310 close to the guide sleeve 200.

[0047] Specifically, the piston rod 300 is passed through the guide sleeve 200 and can move axially along the guide sleeve 200, wherein the guide sleeve 200 is coaxially arranged with the cylinder assembly 100. When the piston rod 300 moves axially along the guide sleeve 200, the supporting member 310 and the supporting portion 320 move together with the piston rod 300.

[0048] It is understood that the abutment 310 is a nut that is sleeved onto the inserted end of the piston rod 300. The abutment 310 is fastened to the inserted end of the piston rod 300 by means of a locking member 330, wherein the locking member 330 may be a locking screw. Of course, in other embodiments, the abutment 310 may also be fixed to the inserted end of the piston rod 300 in other ways.

[0049] The resisting portion 320 is a stepped surface. The resisting portion 320 and the resisting member 310 are spaced apart and arranged opposite to each other along the axial direction of the piston rod 300 , and the resisting portion 320 is located on a side of the resisting member 310 close to the guide sleeve 200 .

[0050] Specifically, the piston rod 300 includes a large diameter section and a small diameter section connected to the large diameter section. The large diameter section and the small diameter section are coaxially arranged. The large diameter section is passed through the guide sleeve 200, and the small diameter section is extended into the interior of the cylinder assembly 100. The extending end of the piston rod 300 is the end of the small diameter section away from the large diameter section, and the supporting portion 320 is the step surface between the large diameter section and the small diameter section.

[0051] The piston assembly 400 is located in the cylinder assembly 100. The piston assembly 400 includes a first piston 410 that is sleeved on the outside of the piston rod 300 and can move along the axial direction of the piston rod 300, and a second piston 420 that is sleeved on the outside of the piston rod 300 and can move along the axial direction of the piston rod 300. The first piston 410 and the second piston 420 are both confined between the abutting portion 320 and the abutting member 310, and the first piston 410 is located on the side of the second piston 420 close to the abutting portion 320. The guide sleeve 200 can also limit the first piston 410.

[0052] Specifically, the outer wall of the first piston 410 and the outer wall of the second piston 420 are both sealed against the inner wall of the cylinder assembly 100, while the inner wall of the first piston 410 and the inner wall of the second piston 420 are both movably engaged with the piston rod 300, allowing the first piston 410 and the second piston 420 to move axially along the piston rod 300. The abutment portion 320 can abut against the side of the first piston 410 away from the second piston 420, and the abutment member 310 can abut against the side of the second piston 420 away from the first piston 410. In this way, the first piston 410 and the second piston 420 can be confined between the abutment portion 320 and the abutment member. In addition, the guide sleeve 200 can also limit the first piston 410, preventing it from escaping from the cylinder assembly 100. In addition, a limiting portion 104 is provided inside the cylinder assembly 100, and the limiting portion 104 is located on the side of the second piston 420 away from the first piston 410. The limiting portion 104 is used to limit the first piston 410. When the second piston 420 is in contact with the limiting portion 104, the piston rod 300 can still continue to move into the interior of the cylinder assembly 100 to move the first piston 410 toward the second piston 420.

[0053] Specifically, the limiting portion 104 is located on the upper end surface of the base 120. The upper end of the base 120 is used to penetrate into the cylinder 110 so that the limiting portion 104 is opposite to the edge of the second piston 420. A clearance cavity is provided in the middle of the base 120 for the piston rod 300 to penetrate.

[0054] An elastic compression member 500 is disposed between the first piston 410 and the second piston 420. The elastic compression member 500 is configured to cause the first piston 410 and the second piston 420 to move away from each other. Thus, in the initial state, under the action of the elastic compression member 500, the abutting portion 320 abuts against the side of the first piston 410 away from the second piston 420, and the abutting member 310 abuts against the side of the second piston 420 away from the first piston 410.

[0055] Specifically, the elastic compression member 500 is a spring, which is sleeved outside the piston rod 300 , and one end of the spring abuts against the first piston 410 , and the other end of the spring abuts against the second spring.

[0056] Of course, in other embodiments, the elastic compression member 500 may also be a spring.

[0057] A buffer chamber 401 is formed between the first piston 410 and the second piston 420. The volume of the buffer chamber 401 changes with the relative position of the first piston 410 and the second piston 420. When the first piston 410 and the second piston 420 are closer, the volume of the buffer chamber 401 is smaller.

[0058] Among them, the first piston 410 is provided with a first oil channel 411; the second piston 420 is provided with a second oil channel 421; one end of the first oil channel 411 is connected to the rod chamber 103 of the cylinder assembly 100, and the other end is connected to one end of the second oil channel 421; the other end of the second oil channel 421 is connected to the rodless chamber 102 of the cylinder assembly 100.

[0059] It should be noted that the piston assembly 400 divides the interior of the cylinder assembly 100 into a rod chamber 103 and a rodless chamber 102 . The piston rod 300 is disposed in the rod chamber 103 , and the rodless chamber oil port 101 is connected to the rodless chamber 102 .

[0060] Among them, the first piston 410 and the second piston 420 can approach each other or move away from each other. At least before the first piston 410 and the second piston 420 are not tightly pressed against each other, the other end of the first oil channel 411 and one end of the second oil channel 421 are still connected to the buffer chamber 401.

[0061] It should be noted that before the first piston 410 and the second piston 420 approach each other and press against each other, the other end of the first oil passage 411 and one end of the second oil passage 421 are both in communication with the buffer chamber 401. In some embodiments, when the first piston 410 and the second piston 420 approach each other and press against each other, the other end of the first oil passage 411 and one end of the second oil passage 421 are also in communication with the buffer chamber 401; whereas in other embodiments, when the first piston 410 and the second piston 420 approach each other and press against each other, the other end of the first oil passage 411 and / or one end of the second oil passage 421 are not in communication with the buffer chamber 401.

[0062] It is understandable that the first piston 410 and the second piston 420 can be nested together when they are close to each other and reduce the volume of the buffer chamber 401 to squeeze out the hydraulic oil in the buffer chamber 401.

[0063] Furthermore, the first piston 410 is also provided with a third oil passage 412 connected to the buffer chamber 401. The third oil passage 412 is sealed by the supporting portion 320 when the first piston 410 abuts against the supporting portion 320. The third oil passage 412 is connected to the rod chamber 103 of the cylinder assembly 100 when the first piston 410 is separated from the supporting portion 320.

[0064] Specifically, one end of the third oil passage 412 is connected to the buffer chamber 401, and the other end is arranged opposite to the supporting portion 320. When the first piston 410 is in abutment with the supporting portion 320, the other end of the third oil passage 412 is sealed by the supporting portion 320. When the first piston 410 is separated from the supporting portion 320, the other end of the third oil passage 412 is connected to the rod chamber 103 of the cylinder assembly 100.

[0065] The operating principle of the hydraulic cylinder of the present invention is as follows:

[0066] like Figure 1 As shown, when the hydraulic oil enters the rodless chamber oil port 101, the hydraulic oil passes through the second oil passage 421 of the second piston 420 and the first oil passage 411 of the first piston 410 to reach the rod chamber 103. At this time, the hydraulic oil can also enter the buffer chamber 401. Under the action of the pressure of the elastic compression member 500 and the hydraulic oil, the first piston 410 can maintain contact with the abutting portion 320 of the piston rod 300, and the second piston 420 can maintain contact with the abutting member 310. At this time, the combination formed by the first piston 410 and the second piston 420 and the piston rod 300 can be pushed away from the rodless chamber oil port 101 by the hydraulic oil.

[0067] When the hydraulic cylinder moves to Figure 2 In the state shown, the first piston 410 is against the guide sleeve 200. When oil continues to flow into the rodless chamber oil port 101, the piston rod 300 together with the abutting piece 310 continues to drive the second piston 420 away from the rodless chamber oil port 101. The first piston 410 cannot continue to move away from the rodless chamber oil port 101 due to the obstruction of the guide sleeve 200. The first piston 410 and the second piston 420 move relative to each other, and the two form a nested relationship. When the piston rod 300 together with the abutting piece 310 continues to drive the second piston 420 away from the rodless chamber oil port 101, the hydraulic oil in the buffer chamber 401 slowly flows out through the fitting gap between the first piston 410 and the second piston 420, forcing the piston rod 300 to reduce its running speed until the second piston 420 abuts against the first piston 410. Figure 3 As shown, the piston rod 300 runs to the upper end point and the rising buffer is completed.

[0068] When the rodless chamber oil port 101 is connected to the return oil tank, the hydraulic oil pressure in the hydraulic cylinder drops and is not enough to balance the load carried by the piston rod 300. The piston rod 300 begins to move toward the rodless chamber oil port 101, and the second piston 420 separates from the guide sleeve 200. The hydraulic oil enters the buffer chamber 401 through the third oil passage 412. Under the action of the elastic compression member 500, the first piston 410 moves upward relative to the second piston 420 until it returns to its initial state. When the assembly continues to descend, it runs to Figure 4When the first piston 410 and the second piston 420 are in contact with each other, the hydraulic oil in the buffer chamber 401 can slowly flow out through the clearance between the first piston 410 and the second piston 420 and the clearance between the second piston 420 and the piston rod 300, forcing the piston rod 300 to reduce its running speed until the first piston 410 and the second piston 420 are in contact with each other. Figure 5 As shown, the piston rod 300 runs to the lower end point and the descent buffering is completed.

[0069] The hydraulic cylinder of the present invention features a compact structure, requiring only precise alignment between the first piston 410 and the second piston 420, and between the second piston 420 and the piston rod 300. This allows for easy control of machining accuracy, eliminating the need for precise alignment between conventional buffer plungers and welded bases, thereby reducing costs. Furthermore, the first piston 410 floats radially within the cylinder assembly 100. This allows for automatic centering during relative motion between the first and second pistons 410, 420, minimizing friction between them, ensuring a good cushioning effect, and extending service life.

[0070] like Figure 1 As shown, it should be noted that, in this embodiment, a first chamber 422 is provided on a side of the second piston 420 close to the first piston 410 , and the first piston 410 can be inserted into the first chamber 422 .

[0071] It can be understood that the first chamber 422 constitutes a part of the buffer chamber 401, and the first piston 410 can be inserted into the first chamber 422, so that the first piston 410 and the second piston 420 are nested together, and the first piston 410 is inserted into the first chamber 422 and as the first pistons 410 get closer to the first pistons 410, the volume of the buffer chamber 401 becomes smaller.

[0072] Combine Figure 1 and Figure 2 Furthermore, the first piston 410 includes a sealing portion 410a that seals with the inner wall of the cylinder assembly 100, and a penetration portion 410b connected to the sealing portion 410a, and the penetration portion 410b can penetrate into the first chamber 422, the outer wall of the penetration portion 410b is spaced from the inner wall of the cylinder assembly 100, and the outer wall of the penetration portion 410b is provided with an oil groove 413, the oil groove 413 is connected to the first oil channel 411, and the oil groove 413 is connected to the second oil channel 421.

[0073] As can be understood, the sealing portion 410a seals against the inner sidewall of the cylinder assembly 100, thereby preventing hydraulic oil from flowing through the gap between the sealing portion 410a and the cylinder assembly 100. The penetrating portion 410b is then able to penetrate into the first chamber 422 until it abuts against the bottom wall of the first chamber 422. The oil passage 413 is formed on the outer sidewall of the penetrating portion 410b. Therefore, before the first piston 410 and the second piston 420 abut against each other, the oil passage 413 connects the first chamber 422 (buffer chamber 401) with the first oil passage 411, and further connects the first chamber 422 (buffer chamber 401) with the second oil passage 421. Thus, when the first piston 410 and the second piston 420 approach each other and squeeze the hydraulic oil in the buffer chamber 401, the hydraulic oil can flow out through the gap between the first piston 410 and the second piston 420 and the oil passage 413.

[0074] It should be noted that the first oil passage 411 is opened in the sealing portion 410a and passes through the upper and lower surfaces of the sealing portion 410a. One end of the first oil passage 411 is connected to the rod cavity 103 of the cylinder assembly 100, and the other end is connected to the gap between the penetration portion 410b and the inner wall of the cylinder assembly 100.

[0075] Furthermore, one end of the second oil passage 421 is communicated with the gap between the penetration portion 410 b and the inner wall of the cylinder assembly 100 , and the other end is communicated with the rodless cavity 102 of the cylinder assembly 100 .

[0076] Furthermore, a second chamber 414 is provided on a side of the penetration portion 410 b close to the second piston 420 , and the second chamber 414 is communicated with the first chamber 422 .

[0077] It can be understood that the second chamber 414 also constitutes a part of the buffer chamber 401. In this way, when the first piston 410 and the second piston 420 approach each other, the volume of the buffer chamber 401 becomes smaller, and when the first piston 410 and the second piston 420 move away from each other, the volume of the buffer chamber 401 becomes larger.

[0078] Furthermore, the outer wall of the penetration portion 410b is guided and matched with the side wall of the first chamber 422. When the first piston 410 and the second piston 420 move relative to each other, they can be automatically aligned, reducing the mutual friction between them, ensuring a good buffering effect and extending the service life.

[0079] Specifically, the outer diameter of the penetration portion 410b is the same as the diameter of the first chamber 422, or the outer diameter of the penetration portion 410b is slightly smaller than the diameter of the first chamber 422. The outer side wall of the penetration portion 410b and the side wall of the first chamber 422 can guide each other, so that the first piston 410 and the second piston 420 are automatically aligned.

[0080] In some embodiments, the first piston 410 seals against the guide sleeve 200 when in contact with the guide sleeve 200. That is, when the first piston 410 is in contact with the guide sleeve 200, the guide sleeve 200 fits the first piston 410, and the guide sleeve 200 can seal the first piston 410, thereby preventing leakage of hydraulic oil.

[0081] In some embodiments, the second piston 420 seals against the abutment 310 when abutting against the abutment 310. That is, when the second piston 420 abuts against the abutment 310, the abutment 310 and the second piston 420 fit together, and the abutment 310 can seal the second piston 420, thereby preventing hydraulic oil leakage.

[0082] The hydraulic cylinder of the present invention features a compact structure, requiring only precise alignment between the first piston 410 and the second piston 420, and between the second piston 420 and the piston rod 300. This allows for easy control of machining accuracy, eliminating the need for precise alignment between conventional buffer plungers and welded bases, thereby reducing costs. Furthermore, the first piston 410 floats radially within the cylinder assembly 100. This allows for automatic centering during relative motion between the first and second pistons 410, 420, minimizing friction between them, ensuring a good cushioning effect, and extending service life.

[0083] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative uses of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0084] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to the embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the claims and their equivalents.

Claims

1. A hydraulic cylinder, characterized in that: include: A cylinder assembly, wherein one end of the cylinder assembly is provided with a rodless cavity oil port, and the other end is provided with a guide sleeve inside; a piston rod, wherein the piston rod is movably arranged in the guide sleeve, and the insertion end of the piston rod is inserted into the cylinder assembly, the insertion end of the piston rod is fixedly connected to a supporting member, and a side wall of the piston rod is formed with a supporting portion spaced from the supporting member, and the supporting portion is located on a side of the supporting member close to the guide sleeve; A piston assembly, the piston assembly is located in the cylinder assembly, the piston assembly includes a first piston sleeved outside the piston rod and movable along the axial direction of the piston rod, and a second piston sleeved outside the piston rod and movable along the axial direction of the piston rod, the first piston and the second piston are both confined between the abutting portion and the abutting member, and the first piston is located on a side of the second piston close to the abutting portion. A limiting portion is further provided inside the cylinder assembly, the limiting portion is located on a side of the second piston away from the first piston, and an elastic compression member is provided between the first piston and the second piston; A buffer chamber is formed between the first piston and the second piston; the first piston is provided with a first oil passage; the second piston is provided with a second oil passage; one end of the first oil passage is communicated with the rod chamber of the cylinder assembly, the other end of the first oil passage is communicated with one end of the second oil passage, and the other end of the second oil passage is communicated with the rodless chamber of the cylinder assembly; the first piston is further provided with a third oil passage communicated with the buffer chamber, the third oil passage is sealed by the abutting portion when the first piston abuts against the abutting portion, and the third oil passage is communicated with the rod chamber of the cylinder assembly when the first piston is separated from the abutting portion; The first piston and the second piston can move closer to or farther from each other, and before the first piston and the second piston are not pressed against each other, the other end of the first oil passage and one end of the second oil passage are both in communication with the buffer chamber; A first chamber is provided on a side of the second piston close to the first piston, and the first piston can be inserted into the first chamber; The first piston includes a sealing portion that seals against the inner sidewall of the cylinder assembly, and a penetration portion connected to the sealing portion, the penetration portion being capable of being penetrated into the first chamber, the outer sidewall of the penetration portion being spaced apart from the inner sidewall of the cylinder assembly, and the outer sidewall of the penetration portion being provided with an oil passage groove, the oil passage groove being in communication with the other end of the first oil passage channel, and the oil passage groove being in communication with one end of the second oil passage channel; One end of the third oil passage is connected to the buffer chamber, and the other end is arranged opposite to the abutting part. When the first piston abuts against the abutting part, the other end of the third oil passage is sealed by the abutting part. When the first piston is separated from the abutting part, the other end of the third oil passage is connected to the rod chamber of the cylinder assembly.

2. The hydraulic cylinder according to claim 1, characterized in that The first oil passage is opened in the sealing portion, and the other end of the first oil passage is communicated with the gap between the outer side wall of the penetration portion and the inner side wall of the cylinder assembly.

3. The hydraulic cylinder according to claim 1, characterized in that One end of the second oil passage is communicated with a gap between an outer side wall of the penetration portion and an inner side wall of the cylinder assembly.

4. The hydraulic cylinder according to claim 1, characterized in that A second chamber is provided on a side of the penetration portion close to the second piston. The second chamber is communicated with the first chamber, and the third oil passage is communicated with the second chamber.

5. The hydraulic cylinder according to claim 1, wherein: The outer side wall of the penetration portion is guided and matched with the side wall of the first cavity.

6. The hydraulic cylinder according to claim 1, characterized in that The elastic compression member is a spring, and the spring is sleeved outside the piston rod.

7. The hydraulic cylinder according to claim 1, characterized in that The cylinder assembly includes a cylinder barrel and a base arranged at one end of the cylinder barrel, and the guide sleeve is arranged inside the other end of the cylinder barrel.

Images