Smooth synchronous telescopic multi-stage oil cylinder

Abstract

The application discloses a stable synchronous telescopic multi-stage oil cylinder, and aims to provide a stable synchronous telescopic multi-stage oil cylinder which is stable in operation, synchronous in telescoping, and can effectively solve the problems of easy movement, jam and disorderly telescoping of the existing multi-stage oil cylinder, and can improve the safety in use. The stable synchronous telescopic multi-stage oil cylinder comprises a vertically-extended main cylinder body, a main piston, an inner cylinder barrel, an inner piston and a one-way valve and a communication channel.

Description

Technical Field

[0001] This invention relates to the field of multi-stage hydraulic cylinder technology, specifically to a smooth and synchronous telescopic multi-stage hydraulic cylinder. Background Technology

[0002] Current multi-stage hydraulic cylinders typically extend in a coarse-to-fine sequence. However, in actual operation, due to differences in the weight and load of each cylinder, and sudden changes in flow and pressure during switching, problems such as jerking and jamming can easily occur. Furthermore, without sequence valve control, disordered extension and retraction can easily occur, such as the finer cylinder extending first or skipping stages, leading to force imbalance and affecting operational safety. For example, Chinese Patent Publication No. CN217401339U, an invention entitled "A Double-Sealed Sequence Valve Structure for a Multi-Stage Telescopic Hydraulic Cylinder," includes a primary cylinder, a secondary cylinder, and a sequence valve assembly, controlling the actions of the primary and secondary cylinders through the sequence valve. It also suffers from the problem of disordered cylinder extension and retraction without sequence valve control, affecting operational safety. Summary of the Invention

[0003] The purpose of this invention is to provide a stable, synchronously telescopic multi-stage hydraulic cylinder that can effectively solve the problems of spurious movement, jamming, and disordered telescopic movement that easily occur in existing multi-stage hydraulic cylinders, affecting the safety of use.

[0004] The technical solution of this invention is: A smooth, synchronous, multi-stage hydraulic cylinder includes: The main cylinder extends vertically, with an oil inlet and outlet port at its bottom and a main directional hole at its top. The main piston is slidably disposed within the main cylinder body; The inner cylinder is slidably and sealed to the main guide hole. Its lower end is sealed and fixedly connected to the main piston. Its upper end is provided with an inner guide hole. The main piston divides the inner cavity of the main cylinder into a rodless main cavity and a rod main cavity. The inner piston is slidably disposed within the inner cylinder. The piston rod is slidably and sealed to the inner guide hole, and its lower end is fixed to the inner piston. The inner piston divides the inner cavity of the inner cylinder into a rodless inner cavity and a rod inner cavity. The inner piston is provided with a piston hole that connects the rodless inner cavity and the rod inner cavity. The check valve and connecting passage are located on the main piston; The top opening is located inside the bottom end of the main cylinder block; When the main piston is against the bottom of the main cylinder, the push-opening part pushes open the valve core of the one-way valve to open the one-way valve; When the check valve is opened, the connecting channel connects the rodless main chamber, the rod main chamber, and the rodless inner chamber. When the check valve is closed, the connecting channel connects the rod-type main chamber with the rodless inner chamber, while the rodless main chamber is not connected to either the rod-type main chamber or the rodless inner chamber. The specific operation of a smooth, synchronous, multi-stage telescopic hydraulic cylinder according to this scheme is as follows: When the smooth synchronous telescopic multi-stage hydraulic cylinder is in its fully retracted state, the main piston rests against the bottom of the main cylinder body, and the inner piston rests against the main piston at the bottom of the inner cylinder. When the smooth synchronous telescopic multi-stage hydraulic cylinder is in its fully retracted state, hydraulic oil enters the rodless main chamber through the inlet and outlet ports. At this time, the top opening part opens the valve core of the one-way valve, thus opening the one-way valve. The connecting passage connects the rodless main chamber, the rod main chamber, and the rodless inner chamber. The hydraulic oil in the rodless main chamber enters the rod main chamber and the rodless inner chamber through the one-way valve and the connecting passage, and then enters the rod inner chamber through the piston hole, completing the initial oil arrangement and ensuring that the oil pressure in the rodless main chamber, the rod main chamber, the rodless inner chamber, and the rod inner chamber is consistent.

[0005] Next, hydraulic oil continues to be input through the inlet and outlet ports, pushing the main piston upward and causing the inner cylinder to extend. Once the top opening separates from the valve core of the one-way valve, the one-way valve closes. Subsequently, as the main piston moves upward and causes the inner cylinder to extend upward, the main piston will squeeze the oil in the rod-side main chamber. Due to the closed one-way valve, some oil in the rod-side main chamber can only enter the rodless inner chamber through the connecting channel, pushing the inner piston upward and thus causing the piston rod to extend upward, achieving synchronous upward extension of the inner cylinder and piston rod (i.e., achieving synchronous extension of the coarse and fine stages of the multi-stage cylinder). Therefore, this scheme allows for smooth and synchronous extension of the multi-stage cylinder, eliminating the impact of sequential switching. It avoids the problems of surging, jamming, and disordered extension caused by coarse and fine stage switching, which affect operational safety, ensuring smooth overall cylinder extension and effectively improving cylinder safety and service life.

[0006] When the multi-stage hydraulic cylinder extends fully, the hydraulic oil input is shut off. The inner piston and piston rod begin to retract under their own weight. During this process, the inner piston compresses the oil in the rodless cavity. Since the one-way valve is closed at this time, some of the oil in the rodless cavity enters the rod cavity through the piston hole, and some enters the rod main cavity through the connecting channel, thereby pushing the main piston to retract downwards. At the same time, the inner cylinder and the main piston also begin to retract under their own weight. During the downward retraction of the main piston, the oil in the rodless main cavity is discharged through the inlet and outlet ports and flows back into the oil tank, thus achieving synchronous downward retraction of the inner cylinder and piston rod (i.e., achieving synchronous retraction of the coarse and fine stages of the multi-stage hydraulic cylinder). This eliminates the impact of sequential switching and avoids the problems of surging, jamming, and disordered extension and retraction caused by coarse and fine stage switching, which affect the safety of use. It ensures the overall smooth operation of the hydraulic cylinder retraction and effectively improves the safety and service life of the hydraulic cylinder.

[0007] Furthermore, when the main piston retracts to the bottom of the main cylinder, the top opening part opens the valve core of the one-way valve to open the one-way valve. At this time, pressure relief is achieved in the rod-type main chamber, the rodless inner chamber, and the rod-type inner chamber, which can avoid the accumulation of fatigue in the various components in the multi-stage cylinder and improve its service life.

[0008] As a preferred option, the connecting channel includes: A mounting hole is provided on the main piston at one end facing the rodless main chamber, and the one-way valve is installed in the mounting hole; A connecting hole is located inside the main piston, connecting the rod-type main chamber and the rodless inner chamber; Connecting hole, connecting the bottom of the mounting hole to the connecting hole.

[0009] Preferably, a retaining ring is provided on the inner wall of the mounting hole, and the one-way valve is limited between the bottom of the mounting hole and the retaining ring. This facilitates the installation, disassembly, and replacement of the one-way valve.

[0010] Preferably, the top of the main cylinder block is provided with a coaxially distributed main guide sleeve, and the inner hole of the main guide sleeve constitutes the main guide hole. This facilitates the actual manufacturing of the main guide hole at the upper end of the main cylinder block.

[0011] Preferably, the upper end of the inner cylinder is provided with an inner guide sleeve coaxially distributed thereon, and the inner hole of the inner guide sleeve constitutes the inner guide hole. This facilitates the actual manufacturing of the inner guide hole at the upper end of the inner cylinder.

[0012] Preferably, the main cylinder body includes a vertically distributed main cylinder barrel and a cylinder bottom cover sealed to the bottom end of the main cylinder barrel. The oil inlet and outlet ports are located inside the cylinder bottom cover, and the top opening is located on the inner end face of the cylinder bottom cover. This facilitates the actual manufacturing of the main cylinder body.

[0013] Preferably, the lower end of the inner cylinder is connected to the main piston via a threaded seal. This facilitates a sealed connection between the inner cylinder and the main piston.

[0014] Preferably, the lower end of the piston rod is threaded onto the inner piston. This facilitates the connection between the piston rod and the inner piston.

[0015] Preferably, explosion-proof valves are installed in the inlet and outlet oil ports. In this way, if the oil pipe bursts or the oil circuit seal fails, the explosion-proof valve can immediately lock the oil cylinder, preventing the oil cylinder from falling rapidly and thus protecting the safety of the oil cylinder user.

[0016] The beneficial effects of this invention are: Firstly, it can achieve synchronous extension of multiple hydraulic cylinders, ensuring smooth operation of the cylinder extension; it can also achieve synchronous retraction of multiple hydraulic cylinders, ensuring smooth operation of the cylinder retraction; there is no impact from sequential switching, which can avoid the problems of swaying, jamming and disordered extension and retraction caused by the switching between coarse and fine stages, which affect the safety of use, and effectively improve the safety and service life of the hydraulic cylinder.

[0017] Secondly, when the main piston retracts to the bottom of the main cylinder, pressure relief can be achieved in the rod-type main chamber, the rodless inner chamber, and the rod-type inner chamber, avoiding the accumulation of fatigue in the components of the multi-stage cylinder, thereby improving the service life of the multi-stage cylinder. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a multi-stage hydraulic cylinder for smooth synchronous telescopic movement according to the present invention.

[0019] Figure 2 yes Figure 1 A magnified view of a portion of point A in the middle.

[0020] In the picture: Main cylinder body 10, oil inlet and outlet ports 10.1, cylinder bottom cover 10.2, main cylinder barrel 10.3, top opening 10.4, rodless main chamber 10.5, rod-type main chamber 10.6; Main piston 20; The inner cylinder is 30mm, the rodless inner cavity is 30.1mm, and the rod-bearing inner cavity is 30.2mm. Internal piston 40, piston bore 40.1; Piston rod 50; Explosion-proof valve 60; One-way valve 70, valve core 70.1; Connecting hole 80, mounting hole 80.1, connecting hole 80.2, connecting hole 80.3; Dominant direction 90; Inner guide sleeve 100. Detailed Implementation

[0021] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Specific Implementation Example 1, such as Figure 1 , Figure 2 As shown, a smooth synchronous telescopic multi-stage hydraulic cylinder includes a main cylinder body 10, a main piston 20, an inner cylinder 30, an inner piston 40, a piston rod 50, a top opening part 10.4, a one-way valve 70, and a connecting channel 80.

[0022] The main cylinder body 10 extends vertically. The bottom end of the main cylinder body 10 has an oil inlet / outlet port 10.1, and the top end has a main directional bore. The main directional bore is coaxially distributed with the main cylinder body 10. The main piston 20 slides within the main cylinder body 10.

[0023] The inner cylinder 30 extends vertically. It is slidably and sealingly connected to the main directional bore; specifically, a sealing ring is provided between the inner cylinder 30 and the main directional bore, and this sealing ring is fixed to the inner wall of the main directional bore. The lower end of the inner cylinder 30 is sealed and fixedly connected to the main piston 20, that is, the lower end of the inner cylinder 30 is fixedly connected to the main piston 20, and the main piston 20 seals and covers the lower end of the inner cylinder 30. In this embodiment, the lower end of the inner cylinder 30 is threadedly and sealingly connected to the main piston 20. This facilitates the sealing connection between the inner cylinder 30 and the main piston 20. The upper end of the inner cylinder 30 is provided with an inner guide hole, which is coaxially distributed with the inner cylinder 30. The inner piston 40 is slidably disposed within the inner cylinder 30.

[0024] The piston rod 50 is slidably and sealingly connected to the inner guide hole. Specifically, a sealing ring is provided between the piston rod 50 and the inner guide hole, and the sealing ring is fixed to the inner wall of the inner guide hole. The lower end of the piston rod 50 is fixed to the inner piston 40. In this embodiment, the lower end of the piston rod 50 is threadedly connected to the inner piston 40. This facilitates the connection between the piston rod 50 and the inner piston 40.

[0025] The inner piston 40 divides the inner cavity of the inner cylinder 30 into a rodless inner cavity 30.1 and a rod inner cavity 30.2. The rod inner cavity 30.2 and the piston rod 50 are located on the same side of the inner piston 40. The inner piston 40 is provided with a piston hole 40.1 that connects the rodless inner cavity 30.1 and the rod inner cavity 30.2.

[0026] The main piston 20 divides the inner cavity of the main cylinder 10 into a rodless main cavity 10.5 and a rod main cavity 10.6. The rod main cavity 10.6 and the inner cylinder 30 are located on the same side of the main piston 20.

[0027] The one-way valve 70 and the connecting passage 80 are located on the main piston 20. The one-way valve 70 contains a valve core 70.1 that controls the opening and closing of the one-way valve 70.

[0028] The top opening portion 10.4 is located inside the bottom end of the main cylinder body 10. The top opening portion 10.4 faces the valve core 70.1 inside the one-way valve 70. The top opening portion 10.4 cooperates with the one-way valve 70 to open the valve core 70.1 of the one-way valve 70, thereby opening the one-way valve 70.

[0029] When the main piston 20 abuts against the bottom of the main cylinder 10, the top opening part 10.4 opens the valve core 70.1 of the one-way valve 70 to open the one-way valve 70.

[0030] When the one-way valve 70 is opened, the connecting channel 80 connects the rodless main chamber 10.5, the rod main chamber 10.6, and the rodless inner chamber 30.1.

[0031] When the one-way valve 70 is closed, the connecting passage 80 connects the rod-type main chamber 10.6 with the rodless inner chamber 30.1, while the rodless main chamber 10.5 is not connected to either the rod-type main chamber 10.6 or the rodless inner chamber 30.1. The rodless main chamber 10.5 is not connected to either the rod-type main chamber 10.6 or the rodless inner chamber 30.1.

[0032] The specific operation of a smooth, synchronous, multi-stage telescopic hydraulic cylinder in this embodiment is as follows: When the smooth synchronous telescopic multi-stage hydraulic cylinder is in the fully retracted state, the main piston 20 abuts against the bottom end of the main cylinder body 10, and the inner piston 40 abuts against the main piston 20 at the bottom end of the inner cylinder 30. When the multi-stage hydraulic cylinder is in its fully retracted state, hydraulic oil enters the rodless main chamber 10.5 through the inlet and outlet ports 10.1. At this time, the top opening part 10.4 opens the valve core 70.1 of the one-way valve 70 to open the one-way valve 70. The connecting passage 80 connects the rodless main chamber 10.5, the rod main chamber 10.6, and the rodless inner chamber 30.1. The hydraulic oil in the rodless main chamber 10.5 enters the rod main chamber 10.6 and the rodless inner chamber 30.1 through the one-way valve 70 and the connecting passage 80, and then enters the rod inner chamber 30.2 through the piston hole, completing the initial oil arrangement and making the oil pressure in the rodless main chamber 10.5, the rod main chamber 10.6, the rodless inner chamber 30.1, and the rod inner chamber 30.2 consistent.

[0033] Next, hydraulic oil continues to be supplied through the inlet and outlet ports 10.1, pushing the main piston 20 upward and causing the inner cylinder 30 to extend. When the top opening 10.4 separates from the valve core 70.1 of the check valve 70, the check valve 70 closes (after the top opening 10.4 separates from the valve core 70.1, the valve core 70.1 resets under the action of the spring in the check valve 70, closing the check valve 70). Subsequently, as the main piston 20 moves upward and causes the inner cylinder 30 to extend upward, the main piston 20 will squeeze the oil in the rod-side main chamber 10.6. Because the check valve 70 is closed, the oil in the rod-side main chamber 10.6... A portion of the oil can only enter the rodless inner cavity 30.1 through the connecting channel 80, pushing the inner piston 40 upward, thereby causing the piston rod 50 to extend upward, realizing the synchronous upward extension of the inner cylinder 30 and the piston rod 50 (that is, realizing the synchronous extension of the coarse and fine stages of the multi-stage hydraulic cylinder); therefore, the multi-stage hydraulic cylinder of this solution can extend synchronously without the impact of sequential switching; it can avoid the problems of spurring, jamming and disordered extension caused by the switching of coarse and fine stages, which affect the safety of use, and ensure the overall smooth operation of the hydraulic cylinder extension, effectively improving the safety and service life of the hydraulic cylinder.

[0034] When the multi-stage hydraulic cylinder extends fully, the hydraulic oil input is shut off. The inner piston 40 and piston rod 50 begin to retract under their own weight. During this process, the inner piston 40 compresses the oil in the rodless inner cavity 30.1. Since the one-way valve 70 is closed at this time, some of the oil in the rodless inner cavity 30.1 enters the rod-side inner cavity 30.2 through the piston hole, and some enters the rod-side main cavity 10.6 through the connecting channel 80, thereby pushing the main piston 20 downwards. Simultaneously, the inner cylinder 30 and the main piston 20 also retract under their own weight. The piston 20 begins to retract downwards; during the downward retraction of the main piston 20, the oil in the rodless main chamber 10.5 is discharged through the inlet and outlet oil ports 10.1 and flows back into the oil tank, thereby realizing the synchronous downward retraction of the inner cylinder 30 and the piston rod 50 (that is, realizing the synchronous retraction of the coarse and fine stages of the multi-stage hydraulic cylinder), which eliminates the impact of sequential switching; it can avoid the problems of surging, jamming and disordered extension and contraction caused by the switching of coarse and fine stages, which affect the safety of use, and ensure the overall smooth operation of the hydraulic cylinder retraction, effectively improving the safety and service life of the hydraulic cylinder.

[0035] The smooth synchronous telescopic multi-stage hydraulic cylinder of this embodiment can achieve synchronous extension of multiple stages of hydraulic cylinders, ensuring the overall smooth operation of the cylinder extension; it can also achieve synchronous retraction of multiple stages of hydraulic cylinders, ensuring the overall smooth operation of the cylinder retraction; there is no impact from sequential switching, which can avoid the problems of swaying, jamming and disordered extension and retraction caused by coarse and fine stage switching, affecting the safety of use, and effectively improving the safety and service life of the hydraulic cylinder.

[0036] Furthermore, when the main piston 20 retracts to the bottom of the main cylinder 10, the top opening part 10.4 opens the valve core 70.1 of the one-way valve 70, thereby opening the one-way valve 70. At this time, the internal pressure of the rod-type main chamber 10.6, the rodless inner chamber 30.1, and the rod-type inner chamber 30.2 is relieved, which can avoid the accumulation of fatigue of various components in the multi-stage cylinder and improve its service life.

[0037] Specific embodiment two, such as Figure 1 , Figure 2 As shown, a smooth synchronous telescopic multi-stage hydraulic cylinder includes a main cylinder body 10, a main piston 20, an inner cylinder 30, an inner piston 40, a piston rod 50, a top opening part 10.4, a one-way valve 70, and a connecting channel 80.

[0038] The main cylinder body 10 extends vertically. The bottom end of the main cylinder body 10 has an oil inlet / outlet port 10.1, and the top end has a main directional bore. The main directional bore is coaxially distributed with the main cylinder body 10. The main piston 20 slides within the main cylinder body 10.

[0039] The inner cylinder 30 extends vertically. It is slidably and sealingly connected to the main directional bore; specifically, a sealing ring is provided between the inner cylinder 30 and the main directional bore, and this sealing ring is fixed to the inner wall of the main directional bore. The lower end of the inner cylinder 30 is sealed and fixedly connected to the main piston 20, that is, the lower end of the inner cylinder 30 is fixedly connected to the main piston 20, and the main piston 20 seals and covers the lower end of the inner cylinder 30. In this embodiment, the lower end of the inner cylinder 30 is threadedly and sealingly connected to the main piston 20. This facilitates the sealing connection between the inner cylinder 30 and the main piston 20. The upper end of the inner cylinder 30 is provided with an inner guide hole, which is coaxially distributed with the inner cylinder 30. The inner piston 40 is slidably disposed within the inner cylinder 30.

[0040] The piston rod 50 is slidably and sealingly connected to the inner guide hole. Specifically, a sealing ring is provided between the piston rod 50 and the inner guide hole, and the sealing ring is fixed to the inner wall of the inner guide hole. The lower end of the piston rod 50 is fixed to the inner piston 40. In this embodiment, the lower end of the piston rod 50 is threadedly connected to the inner piston 40. This facilitates the connection between the piston rod 50 and the inner piston 40.

[0041] The inner piston 40 divides the inner cavity of the inner cylinder 30 into a rodless inner cavity 30.1 and a rod inner cavity 30.2. The rod inner cavity 30.2 and the piston rod 50 are located on the same side of the inner piston 40. The inner piston 40 is provided with a piston hole 40.1 that connects the rodless inner cavity 30.1 and the rod inner cavity 30.2.

[0042] The main piston 20 divides the inner cavity of the main cylinder 10 into a rodless main cavity 10.5 and a rod main cavity 10.6. The rod main cavity 10.6 and the inner cylinder 30 are located on the same side of the main piston 20.

[0043] The one-way valve 70 and the connecting passage 80 are located on the main piston 20. The one-way valve 70 contains a valve core 70.1 that controls the opening and closing of the one-way valve 70.

[0044] The top opening portion 10.4 is located inside the bottom end of the main cylinder body 10. The top opening portion 10.4 faces the valve core 70.1 inside the one-way valve 70. The top opening portion 10.4 cooperates with the one-way valve 70 to open the valve core 70.1 of the one-way valve 70, thereby opening the one-way valve 70.

[0045] When the main piston 20 abuts against the bottom of the main cylinder 10, the top opening part 10.4 opens the valve core 70.1 of the one-way valve 70 to open the one-way valve 70.

[0046] When the one-way valve 70 is opened, the connecting channel 80 connects the rodless main chamber 10.5, the rod main chamber 10.6, and the rodless inner chamber 30.1.

[0047] When the one-way valve 70 is closed, the connecting passage 80 connects the rod-type main chamber 10.6 with the rodless inner chamber 30.1, while the rodless main chamber 10.5 is not connected to either the rod-type main chamber 10.6 or the rodless inner chamber 30.1. The rodless main chamber 10.5 is not connected to either the rod-type main chamber 10.6 or the rodless inner chamber 30.1.

[0048] The specific operation of a smooth, synchronous, multi-stage telescopic hydraulic cylinder in this embodiment is as follows: When the smooth synchronous telescopic multi-stage hydraulic cylinder is in the fully retracted state, the main piston 20 abuts against the bottom end of the main cylinder body 10, and the inner piston 40 abuts against the main piston 20 at the bottom end of the inner cylinder 30. When the multi-stage hydraulic cylinder is in its fully retracted state, hydraulic oil enters the rodless main chamber 10.5 through the inlet and outlet ports 10.1. At this time, the top opening part 10.4 opens the valve core 70.1 of the one-way valve 70 to open the one-way valve 70. The connecting passage 80 connects the rodless main chamber 10.5, the rod main chamber 10.6, and the rodless inner chamber 30.1. The hydraulic oil in the rodless main chamber 10.5 enters the rod main chamber 10.6 and the rodless inner chamber 30.1 through the one-way valve 70 and the connecting passage 80, and then enters the rod inner chamber 30.2 through the piston hole, completing the initial oil arrangement and making the oil pressure in the rodless main chamber 10.5, the rod main chamber 10.6, the rodless inner chamber 30.1, and the rod inner chamber 30.2 consistent.

[0049] Next, hydraulic oil continues to be supplied through the inlet and outlet ports 10.1, pushing the main piston 20 upward and causing the inner cylinder 30 to extend. When the top opening 10.4 separates from the valve core 70.1 of the check valve 70, the check valve 70 closes (after the top opening 10.4 separates from the valve core 70.1, the valve core 70.1 resets under the action of the spring in the check valve 70, closing the check valve 70). Subsequently, as the main piston 20 moves upward and causes the inner cylinder 30 to extend upward, the main piston 20 will squeeze the oil in the rod-side main chamber 10.6. Because the check valve 70 is closed, the oil in the rod-side main chamber 10.6... A portion of the oil can only enter the rodless inner cavity 30.1 through the connecting channel 80, pushing the inner piston 40 upward, thereby causing the piston rod 50 to extend upward, realizing the synchronous upward extension of the inner cylinder 30 and the piston rod 50 (that is, realizing the synchronous extension of the coarse and fine stages of the multi-stage hydraulic cylinder); therefore, the multi-stage hydraulic cylinder of this solution can extend synchronously without the impact of sequential switching; it can avoid the problems of spurring, jamming and disordered extension caused by the switching of coarse and fine stages, which affect the safety of use, and ensure the overall smooth operation of the hydraulic cylinder extension, effectively improving the safety and service life of the hydraulic cylinder.

[0050] When the multi-stage hydraulic cylinder extends fully, the hydraulic oil input is shut off. The inner piston 40 and piston rod 50 begin to retract under their own weight. During this process, the inner piston 40 compresses the oil in the rodless inner cavity 30.1. Since the one-way valve 70 is closed at this time, some of the oil in the rodless inner cavity 30.1 enters the rod-side inner cavity 30.2 through the piston hole, and some enters the rod-side main cavity 10.6 through the connecting channel 80, thereby pushing the main piston 20 downwards. Simultaneously, the inner cylinder 30 and the main piston 20 also retract under their own weight. The piston 20 begins to retract downwards; during the downward retraction of the main piston 20, the oil in the rodless main chamber 10.5 is discharged through the inlet and outlet oil ports 10.1 and flows back into the oil tank, thereby realizing the synchronous downward retraction of the inner cylinder 30 and the piston rod 50 (that is, realizing the synchronous retraction of the coarse and fine stages of the multi-stage hydraulic cylinder), which eliminates the impact of sequential switching; it can avoid the problems of surging, jamming and disordered extension and contraction caused by the switching of coarse and fine stages, which affect the safety of use, and ensure the overall smooth operation of the hydraulic cylinder retraction, effectively improving the safety and service life of the hydraulic cylinder.

[0051] The smooth synchronous telescopic multi-stage hydraulic cylinder of this embodiment can achieve synchronous extension of multiple stages of hydraulic cylinders, ensuring the overall smooth operation of the cylinder extension; it can also achieve synchronous retraction of multiple stages of hydraulic cylinders, ensuring the overall smooth operation of the cylinder retraction; there is no impact from sequential switching, which can avoid the problems of swaying, jamming and disordered extension and retraction caused by coarse and fine stage switching, affecting the safety of use, and effectively improving the safety and service life of the hydraulic cylinder.

[0052] Furthermore, when the main piston 20 retracts to the bottom of the main cylinder 10, the top opening part 10.4 opens the valve core 70.1 of the one-way valve 70, thereby opening the one-way valve 70. At this time, the internal pressure of the rod-type main chamber 10.6, the rodless inner chamber 30.1, and the rod-type inner chamber 30.2 is relieved, which can avoid the accumulation of fatigue of various components in the multi-stage cylinder and improve its service life.

[0053] Furthermore, such as Figure 1 As shown, the main cylinder body 10 includes a vertically distributed main cylinder barrel 10.3 and a cylinder bottom cover 10.2 sealed to the bottom end of the main cylinder barrel 10.3. Oil inlet and outlet ports 10.1 are located inside the cylinder bottom cover 10.2. A top opening 10.4 is located on the inner end face of the cylinder bottom cover 10.2. This facilitates the actual manufacturing of the main cylinder body 10.

[0054] In one example, the top opening 10.4 is formed by a top opening protrusion, which is an integral structure with the cylinder bottom cover 10.2. The top opening protrusion is located in the middle of the inner end face of the cylinder bottom cover 10.2.

[0055] In another example, the top opening 10.4 is formed by a push rod, which is an integral structure with the cylinder bottom cover 10.2, or the push rod is fixed to the middle of the inner end face of the cylinder bottom cover 10.2 by thread or welding. The push rod is coaxially distributed with the main cylinder 10.3.

[0056] The cylinder bottom cover 10.2 and the bottom end of the main cylinder 10.3 are connected by welding seal; or the cylinder bottom cover 10.2 and the bottom end of the main cylinder 10.3 are connected by thread seal; or the cylinder bottom cover 10.2 and the bottom end of the main cylinder 10.3 are connected by bolts, and a sealing ring or sealing gasket is provided between the cylinder bottom cover 10.2 and the bottom end of the main cylinder 10.3.

[0057] Furthermore, such as Figure 1 , Figure 2 As shown, the connecting channel 80 includes a mounting hole 80.1, a connecting hole 80.2, and a linking hole 80.3. The mounting hole 80.1 is located on the main piston 20 at one end facing the rodless main chamber 10.5. In this embodiment, the mounting hole 80.1 is coaxially distributed with the main piston 20. The one-way valve 70 is installed inside the mounting hole 80.1. The connecting hole 80.2 is located inside the main piston 20, connecting the rod-type main chamber 10.6 and the rodless inner chamber 30.1. The linking hole 80.3 connects the bottom of the mounting hole 80.1 to the connecting hole 80.2. Thus, when the one-way valve 70 is opened, the connecting channel 80 connects the rodless main chamber 10.5, the rod-type main chamber 10.6, and the rodless inner chamber 30.1. When the one-way valve 70 is closed, the connecting hole 80.2 of the connecting channel 80 connects the rod-type main cavity 10.6 with the rodless inner cavity 30.1, while the rodless main cavity 10.5 is not connected to either the rod-type main cavity 10.6 or the rodless inner cavity 30.1.

[0058] In one embodiment of this invention, a retaining ring is provided on the inner wall of the mounting hole 80.1, and the one-way valve 70 is positioned between the bottom of the mounting hole 80.1 and the retaining ring. This facilitates the installation, removal, and replacement of the one-way valve 70.

[0059] In another embodiment of this invention, the check valve 70 is threaded into the mounting hole 80.1. This facilitates the installation, removal, and replacement of the check valve 70.

[0060] Furthermore, such as Figure 1 As shown, a main guide sleeve 90 is coaxially distributed at the top of the main cylinder body 10, and the main guide sleeve 90 is located inside the main cylinder body 10. The inner hole of the main guide sleeve 90 constitutes the main guide hole. This facilitates the actual fabrication of the main guide hole at the upper end of the main cylinder body 10.

[0061] In one embodiment of this invention, the main guide sleeve 90 is threadedly installed to the top of the main cylinder body 10, the main guide sleeve 90 is located inside the main cylinder body 10, and a sealing ring is provided between the main guide sleeve 90 and the main cylinder body 10.

[0062] In another embodiment of this invention, the main guide sleeve 90 is connected to the top of the main cylinder body 10 by welding, the main guide sleeve 90 is located inside the main cylinder body 10, and a sealing ring is provided between the main guide sleeve 90 and the main cylinder body 10.

[0063] Furthermore, such as Figure 1 As shown, an inner guide sleeve 100 is coaxially distributed at the upper end of the inner cylinder 30, and the inner guide sleeve 100 is located inside the upper end of the inner cylinder 30. The inner hole of the inner guide sleeve 100 constitutes the inner guide hole. This facilitates the actual fabrication of the inner guide hole at the upper end of the inner cylinder 30.

[0064] In one embodiment of this invention, the inner guide sleeve 100 is threaded together with the upper end of the inner cylinder 30. The inner guide sleeve 100 is located inside the upper end of the inner cylinder 30, and a sealing ring is provided between the inner guide sleeve 100 and the inner cylinder 30.

[0065] In another embodiment of this invention, the inner guide sleeve 100 is connected to the upper end of the inner cylinder 30 by welding. The inner guide sleeve 100 is located inside the upper end of the inner cylinder 30, and a sealing ring is provided between the inner guide sleeve 100 and the inner cylinder 30.

[0066] Furthermore, such as Figure 1 As shown, an explosion-proof valve 60 is installed inside the oil inlet and outlet ports 10.1. In this way, if the oil cylinder experiences a pipeline rupture or oil circuit seal failure, the explosion-proof valve 60 can immediately lock the oil cylinder, preventing it from falling rapidly and thus protecting the safety of the oil cylinder user.

[0067] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications, alterations, and equivalent transformations made to the above embodiments based on the technical essence of the present invention shall still fall within the protection scope of the present invention.

Claims

1. A smooth, synchronous, multi-stage telescopic hydraulic cylinder, characterized in that, include: The main cylinder body (10) extends vertically, with an oil inlet and outlet port at the bottom and a main directional hole at the top; The main piston (20) is located inside the main cylinder. The inner cylinder (30) is slidably and sealed to the main guide hole. Its lower end is sealed and fixedly connected to the main piston. Its upper end is provided with an inner guide hole. The main piston divides the inner cavity of the main cylinder into a rodless main cavity and a rod main cavity. An inner piston (40) is located inside the inner cylinder. The piston rod is slidably and sealed to the inner guide hole, and its lower end is fixed to the inner piston. The inner piston divides the inner cavity of the inner cylinder into a rodless inner cavity and a rod inner cavity. The inner piston is provided with a piston hole that connects the rodless inner cavity and the rod inner cavity. The check valve and connecting passage are located on the main piston; The top opening is located inside the bottom end of the main cylinder block.

2. The smooth synchronous telescopic multi-stage hydraulic cylinder according to claim 1, characterized in that, When the main piston (20) abuts against the bottom of the main cylinder (10), the top opening part (10.4) opens the valve core of the one-way valve (70) to open the one-way valve (70). When the one-way valve (70) is opened, the connecting channel (80) connects the rodless main chamber (10.5), the rod main chamber (10.6), and the rodless inner chamber (30.1); When the one-way valve (70) is closed, the connecting channel (80) connects the rod-type main cavity (10.6) with the rodless inner cavity (30.1), and the rodless main cavity (10.5) is not connected to the rod-type main cavity (10.6) and the rodless inner cavity (30.1).

3. The smooth synchronous telescopic multi-stage hydraulic cylinder according to claim 1, characterized in that, The connecting channel (80) includes: Mounting hole (80.1) is provided on the main piston (20) at one end facing the rodless main chamber (10.5), and the one-way valve (70) is installed in mounting hole (80.1); A connecting hole (80.2) is provided inside the main piston (20) to connect the rod-type main cavity (10.6) and the rodless inner cavity (30.1). Connecting hole (80.3) connects the bottom of mounting hole (80.1) to connecting hole (80.2).

4. The smooth synchronous telescopic multi-stage hydraulic cylinder according to claim 3, characterized in that, A retaining ring is provided on the inner wall of the mounting hole (80.1), and the one-way valve (70) is limited between the bottom of the mounting hole (80.1) and the retaining ring.

5. A smooth, synchronous, multi-stage telescopic hydraulic cylinder according to claim 1, 2, 3, or 4, characterized in that, The top of the main cylinder (10) is provided with a coaxially distributed main guide sleeve (90), and the inner hole of the main guide sleeve (90) constitutes the main guide hole.

6. A smooth, synchronous, multi-stage telescopic hydraulic cylinder according to claim 1, 2, 3, or 4, characterized in that, The inner cylinder (30) is provided with an inner guide sleeve (100) coaxially distributed at the upper end, and the inner hole of the inner guide sleeve (100) constitutes the inner guide hole.

7. A smooth, synchronous, multi-stage telescopic hydraulic cylinder according to claim 1, 2, 3, or 4, characterized in that, The main cylinder body (10) includes a vertically distributed main cylinder barrel (10.3) and a cylinder bottom cover (10.2) sealed and connected to the bottom end of the main cylinder barrel (10.3). The oil inlet and outlet are located inside the cylinder bottom cover (10.2), and the top opening (10.4) is located on the inner end face of the cylinder bottom cover (10.2).

8. A smooth, synchronous, multi-stage telescopic hydraulic cylinder according to claim 1, 2, 3, or 4, characterized in that, The lower end of the inner cylinder (30) is connected to the main piston (20) by a threaded seal.

9. A smooth, synchronous, multi-stage telescopic hydraulic cylinder according to claim 1, 2, 3, or 4, characterized in that, The lower end of the piston rod (50) is threadedly connected to the inner piston (40).

10. A smooth, synchronous, multi-stage telescopic hydraulic cylinder according to claim 1, 2, 3, or 4, characterized in that, An explosion-proof valve (60) is installed in the oil inlet and outlet ports.

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