Mechanical locking two-stage hydraulic cylinder

Abstract

The present invention provides a mechanically locked two-stage hydraulic cylinder, wherein a first piston rod is slidably mounted in a first cylinder body, and a second piston rod is slidably mounted in the first piston rod, and a first oil port and a second oil port are respectively provided near the two ends of the first cylinder body; a first central oil passage connecting the end face and the inner cavity of the first piston rod is provided at the end of the first piston rod away from the second piston rod, and a third oil passage is provided at the end of the second piston rod close to the free end, and the third oil passage is connected to the inner cavity of the first piston rod through the second central oil passage and the side wall oil passage; a first locking device is provided between the second piston rod and the first cylinder body; and a second locking device is provided between the first piston rod and the second piston rod. By adopting the above structure, the oil inlet mode of the hydraulic oil is controlled, so that the hydraulic cylinder can be mechanically locked when it moves to the ends of the two-stage stroke, and can be shut down after the stroke is in place to reduce power consumption, and the system has high reliability.

Description

Technical Field

[0001] The invention relates to a hydraulic cylinder structure, in particular to a mechanically locked two-stage hydraulic cylinder. Background Art

[0002] There is a working condition that requires the hydraulic cylinder to extend to two working positions and maintain high precision for a long time. The hydraulic cylinder structure in the prior art requires the hydraulic oil to maintain pressure continuously, and the working precision is difficult to ensure.

[0003] Chinese patent document CN104776085A records a strong mechanical self-locking hydraulic cylinder with buffer. When the hydraulic cylinder is in the unlocked state, the rodless chamber is pressurized. When the piston rod reaches the end of the stroke, the support block enters the steel ball rack. The hydraulic cylinder self-locks by using the compression spring, steel ball, locking block and steel ball rack. The hydraulic cylinder is unlocked by pressurizing the rod chamber. The buffer sleeve is mounted on the buffer nut. The return buffer is achieved by forming an annular oil gap between the buffer sleeve and the inner diameter of the cylinder cover that is smaller than the annular oil gap between the buffer sleeve and the locking nut. The hydraulic cylinder of the present invention is reliable in locking and easy to unlock. The buffer structure can slow down the running speed of the retracted end and avoid the impact of the retracted end. When the hydraulic cylinder is started, the hydraulic oil can pass through the fast oil gap, and the slow starting speed will not occur. However, this structure can only achieve the locking of one working position and cannot meet the requirements of working conditions. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a mechanical locking two-stage hydraulic cylinder which can adapt to the working conditions of locking in two working positions and requires reliable locking and long locking time.

[0005] In order to solve the above technical problems, the technical solution adopted by the present invention is: a mechanical locking two-stage hydraulic cylinder, the first piston rod is slidably installed in the first cylinder body, the second piston rod is slidably installed in the first piston rod, and the first oil port and the second oil port are respectively provided at positions close to the two ends of the first cylinder body;

[0006] A first central oil passage connecting the end surface of the first piston rod and the inner cavity is provided at one end of the first piston rod away from the second piston rod, and a third oil port is provided at one end of the second piston rod close to the free end, and the third oil port is connected to the inner cavity of the first piston rod through the second central oil passage and the side wall oil passage;

[0007] A first locking device is provided between the second piston rod and the first cylinder body;

[0008] A second locking device is provided between the first piston rod and the second piston rod.

[0009] In a preferred solution, a first buffer cavity is provided at the bottom of the first cylinder body, and a first buffer sleeve is provided at the bottom of the first piston rod to form a seal with the inner wall of the first buffer cavity;

[0010] A second buffer cavity is arranged at the bottom of the inner cavity of the first piston rod, and a second buffer sleeve is arranged at the bottom of the second piston rod to form a seal with the inner wall of the second buffer cavity.

[0011] In a preferred solution, the first oil port is connected to the first buffer chamber, and a first end surface oil groove is provided on the bottom end surface of the first piston rod, and the first end surface oil groove connects the first central oil passage with the first buffer chamber.

[0012] In a preferred solution, a second end surface oil passage groove is provided on the bottom end surface of the second piston rod, and the second end surface oil passage groove connects the first central oil passage with the second buffer chamber.

[0013] In a preferred solution, at the bottom of the first piston rod, the first piston is slidably and sealingly connected to the first piston rod, a first disc spring is provided between the first piston and the first buffer sleeve, the first locking block is slidably connected to the first piston, and a first spring is provided between the first locking block and the first piston;

[0014] The first end cover of the first piston rod is provided with a first steel ball which moves in a radial direction.

[0015] In a preferred embodiment, the first locking block is provided with an edge extending toward the first end cover, a first support block is provided between the edge and the outer wall of the first piston rod, a first ball socket is provided on the first support block, and a space for accommodating the first steel ball is formed between the first ball socket and the edge of the first locking block.

[0016] In a preferred solution, at the bottom of the second piston rod, the second piston is slidably sealedly connected to the second piston rod, a second disc spring is provided between the second piston and the second buffer sleeve, the second locking block is slidably connected to the second piston, and a second spring is provided between the second locking block and the second piston;

[0017] The second end cover of the second piston rod is provided with a second steel ball which moves in a radial direction.

[0018] In a preferred embodiment, the second locking block is provided with an edge extending toward the second end cover, a second support block is provided between the edge and the outer wall of the second piston rod, a second ball socket is provided on the second support block, and a space for accommodating a second steel ball is formed between the second ball socket and the edge of the second locking block.

[0019] In a preferred solution, the side wall oil passage is located at the position of the second spring.

[0020] In a preferred solution, within the sliding stroke of the second piston, an oil groove is further provided on the inner wall of the second piston and / or the outer wall of the second piston rod to keep the side wall oil path connected within the sliding stroke of the second piston.

[0021] The present invention provides a mechanically locked two-stage hydraulic cylinder, which controls the oil inlet method of the hydraulic oil by adopting the above-mentioned structure, so that the hydraulic cylinder can be mechanically locked when it moves to the end of the two-stage stroke, and can be shut down after the stroke is in place to reduce power consumption. Even if the hydraulic system loses pressure due to hydraulic leakage or other reasons, the cylinder can still be maintained in the fully extended state of each stage for a long time, and the system reliability is high. It is suitable for working conditions that require precise locking at two working positions. In the preferred embodiment, when the piston rod of the hydraulic cylinder of the present invention is retracted to the bottom of the stroke, the buffer sleeve will form a buffering effect to prevent the piston from colliding violently with the bottom of the cylinder. Reduce impact vibration and improve system safety. The hydraulic cylinder of the present invention can be maintained in multiple fully extended states for a long time, and can be applied to devices with high position holding accuracy, such as solar panel angle adjustment devices and other equipment, with high reliability and good safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments:

[0023] Figure 1 It is a front view half-section schematic diagram of the present invention.

[0024] In the figure: the first oil port 1, the first buffer sleeve 2, the first disc spring 3, the first piston 4, the first spring 5, the first locking block 6, the first support block 7, the second buffer sleeve 8, the second disc spring 9, the second piston 10, the second spring 11, the second locking block 12, the second support block 13, the first piston rod 14, the second oil port 15, the first steel ball 16, the second piston rod 17, the second steel ball 18, the third oil port 19, the first end face oil groove 20, the first center oil passage 21, the first cylinder body 22, the second end face oil groove 23, the side wall oil passage 24, the second center oil passage 25, the first ball socket 26, the second ball socket 27, the first buffer cavity 28, the second buffer cavity 29, the first end cover 30, and the second end cover 31. DETAILED DESCRIPTION

[0025] like Figure 1 In a mechanical locking two-stage hydraulic cylinder, a first piston rod 14 is slidably mounted in a first cylinder body 22, a second piston rod 17 is slidably mounted in the first piston rod 14, and a first oil port 1 and a second oil port 15 are respectively provided near both ends of the first cylinder body 22;

[0026] The end of the first piston rod 14 away from the second piston rod 17 is provided with a first central oil passage 21 connecting the end surface and the inner cavity of the first piston rod 14, and the end of the second piston rod 17 close to the free end is provided with a third oil port 19, and the third oil port 19 is connected with the inner cavity of the first piston rod 14 through the second central oil passage 25 and the side wall oil passage 24;

[0027] A first locking device is provided between the second piston rod 17 and the first cylinder body 22;

[0028] A second locking device is provided between the first piston rod 14 and the second piston rod 17. With this structure, high-pressure hydraulic oil is introduced from the first oil port 1, the second oil port 15 and the third oil port 19 respectively, so as to control the extension and retraction of the first piston rod 14 and the second piston rod 17, and lock the current state at the limit position through the locking device, so as to maintain the working state for a long time.

[0029] In a preferred solution, a first buffer chamber 28 is provided at the bottom of the first cylinder body 22, and a first buffer sleeve 2 is provided at the bottom of the first piston rod 14 to form a seal with the inner wall of the first buffer chamber 28;

[0030] A second buffer cavity 29 is provided at the bottom of the inner cavity of the first piston rod 14, and a second buffer sleeve 8 is provided at the bottom of the second piston rod 17 to form a seal with the inner wall of the second buffer cavity 29. This structure can buffer the impact of the piston rod on the cylinder body.

[0031] In a preferred solution, the first oil port 1 is connected to the first buffer chamber 28, and a first end surface oil groove 20 is provided on the bottom end surface of the first piston rod 14, and the first end surface oil groove 20 connects the first central oil passage 21 with the first buffer chamber 28. With this structure, it is convenient to expand the effective area of ​​the hydraulic force on the first piston rod 14.

[0032] In a preferred solution, a second end surface oil groove 23 is provided on the bottom end surface of the second piston rod 17, and the second end surface oil groove 23 connects the first central oil passage 21 with the second buffer chamber 29. This structure facilitates expanding the effective area of ​​the hydraulic force on the second piston rod 17.

[0033] In a preferred embodiment, at the bottom of the first piston rod 14, the first piston 4 is slidably and sealedly connected to the first piston rod 14, a first disc spring 3 is provided between the first piston 4 and the first buffer sleeve 2, a first locking block 6 is slidably connected to the first piston 4, and a first spring 5 is provided between the first locking block 6 and the first piston 4;

[0034] A first steel ball 16 that moves in a radial direction is provided on the first end cover 30 of the first piston rod 14 .

[0035] In the preferred embodiment, the first locking block 6 is provided with an edge extending in the direction of the first end cover 30, a first support block 7 is provided between the edge and the outer wall of the first piston rod 14, a first ball socket 26 is provided on the first support block 7, and a space for accommodating the first steel ball 16 is formed between the first ball socket 26 and the edge of the first locking block 6.

[0036] In a preferred embodiment, at the bottom of the second piston rod 17, the second piston 10 is slidably sealed with the second piston rod 17, a second disc spring 9 is provided between the second piston 10 and the second buffer sleeve 8, a second locking block 12 is slidably connected with the second piston 10, and a second spring 11 is provided between the second locking block 12 and the second piston 10;

[0037] A second steel ball 18 that moves in radial direction is provided on the second end cover 31 of the second piston rod 17 .

[0038] In a preferred solution, the second locking block 12 is provided with an edge extending toward the second end cover 31, a second support block 13 is provided between the edge and the outer wall of the second piston rod 17, a second ball socket 27 is provided on the second support block 13, and a space for accommodating the second steel ball 18 is formed between the second ball socket 27 and the edge of the second locking block 12. The above structure facilitates automatic locking and unlocking using hydraulic oil.

[0039] In a preferred solution, the side wall oil passage 24 is located at the position of the second spring 11 .

[0040] Part of the side wall oil passage 24 is located at the second piston rod 17, and the other part is located at the second piston 10. It is easy to be blocked or cause oil pressure instability during the sliding process of the second piston 10. In a further preferred solution, within the sliding stroke of the second piston 10, an oil groove is further provided on the inner wall of the second piston 10 and / or the outer wall of the second piston rod 17, so that the side wall oil passage 24 remains connected within the sliding stroke of the second piston 10. With this structure, the problem of the side wall oil passage 24 being blocked during the sliding unlocking process of the second piston 10 is overcome.

[0041] When in use, when high-pressure hydraulic oil is introduced into the first oil port 1, the high-pressure hydraulic oil pushes the first piston rod 14 to Figure 1 The first locking block 6 moves to the right until it contacts the first steel ball 16. The first locking block 6 retreats, and the first steel ball 16 falls into the first ball socket 26. Under the action of the first spring 5, the first locking block 6 moves forward to lock the first steel ball 16. The first steel ball 16 is installed on a steel ball seat that is fixed and pressed by the first end cover 30. The steel ball seat is provided with a plurality of holes, and the first steel ball 16 moves in series in the hole. Thus, the first-stage working position is locked. The high-pressure hydraulic oil continues to be introduced, and the high-pressure hydraulic oil acts on the end face of the second piston 10 from the first central oil circuit 21 and the second end face through the oil groove 23. The second piston rod 17 moves to the right until the second locking block 12 locks the second steel ball 18, thereby achieving the locking of the first-stage working position.

[0042] When high-pressure hydraulic oil is introduced into the third oil port 19, the second piston 10 is pushed to the left by the hydraulic oil through the second center oil passage 25 and the side wall oil passage 24, compressing the second disc spring 9, the second steel ball 18 is disengaged from the second support block 13, the lock of the second piston rod 17 is released, and the second piston rod 17 retracts. When approaching the bottom of the stroke, the buffer sleeve will form a buffering effect to prevent the piston from colliding violently with the bottom of the cylinder; when high-pressure hydraulic oil is introduced into the second oil port 15, the lock of the first piston rod 14 is released, and the first piston rod 14 retracts.

[0043] In actual working conditions, the first piston rod 14 and the second piston rod 17 may extend at the same time. At this time, a high-pressure hydraulic oil is introduced into the first oil port 1, and another high-pressure hydraulic oil is introduced into the third oil port 19. Due to the back pressure of the third oil port 19, the second piston rod 17 will not extend at this time, ensuring that it can be locked in the first-stage working position. Or after the first piston rod 14 and the second piston rod 17 are fully extended, high-pressure hydraulic oil is introduced into the third oil port 19 to retract the second piston rod 17. In this way, the locking of the single-stage piston rod extension is achieved.

[0044] The above embodiments are only preferred technical solutions of the present invention and should not be regarded as limitations of the present invention. The technical features recorded in the present invention can be freely combined without conflict. The protection scope of the present invention shall be the technical solutions recorded in the claims, including the equivalent replacement solutions of the technical features in the technical solutions recorded in the claims. That is, equivalent replacement improvements within this scope are also within the protection scope of the present invention.

Claims

1. A mechanical locking two-stage hydraulic cylinder, characterized by: The first piston rod (14) is slidably mounted in the first cylinder body (22), the second piston rod (17) is slidably mounted in the first piston rod (14), and a first oil port (1) and a second oil port (15) are respectively provided near two ends of the first cylinder body (22); A first central oil passage (21) connecting the end surface and the inner cavity of the first piston rod (14) is provided at one end of the first piston rod (14) away from the second piston rod (17); a third oil port (19) is provided at one end of the second piston rod (17) close to the free end; the third oil port (19) is connected to the inner cavity of the first piston rod (14) via a second central oil passage (25) and a side wall oil passage (24); A first locking device is provided between the second piston rod (17) and the first cylinder body (22); A second locking device is provided between the first piston rod (14) and the second piston rod (17); A first buffer chamber (28) is provided at the bottom of the first cylinder body (22), and a first buffer sleeve (2) is provided at the bottom of the first piston rod (14) to form a seal with the inner wall of the first buffer chamber (28); A second buffer cavity (29) is provided at the bottom of the inner cavity of the first piston rod (14), and a second buffer sleeve (8) is provided at the bottom of the second piston rod (17) to form a seal with the inner wall of the second buffer cavity (29); The first oil port (1) is in communication with the first buffer chamber (28); a first end surface oil groove (20) is provided on the bottom end surface of the first piston rod (14); the first end surface oil groove (20) connects the first central oil passage (21) with the first buffer chamber (28); A second end surface oil groove (23) is provided on the bottom end surface of the second piston rod (17), and the second end surface oil groove (23) connects the first central oil passage (21) with the second buffer chamber (29); At the bottom of the first piston rod (14), the first piston (4) is slidably sealedly connected to the first piston rod (14), a first disc spring (3) is provided between the first piston (4) and the first buffer sleeve (2), a first locking block (6) is slidably connected to the first piston (4), and a first spring (5) is provided between the first locking block (6) and the first piston (4); A first steel ball (16) that moves in a radial direction is provided on a first end cover (30) of the first piston rod (14); The first locking block (6) is provided with an edge extending in the direction of the first end cover (30), a first supporting block (7) is provided between the edge and the outer wall of the first piston rod (14), a first ball socket (26) is provided on the first supporting block (7), and a space for accommodating the first steel ball (16) is formed between the first ball socket (26) and the edge of the first locking block (6); At the bottom of the second piston rod (17), the second piston (10) is slidably sealedly connected to the second piston rod (17), a second disc spring (9) is provided between the second piston (10) and the second buffer sleeve (8), a second locking block (12) is slidably connected to the second piston (10), and a second spring (11) is provided between the second locking block (12) and the second piston (10); The side wall oil passage (24) is located at the position of the second spring (11); A second steel ball (18) that moves in a radial direction is provided on the second end cover (31) of the second piston rod (17); The second locking block (12) is provided with an edge extending in the direction of the second end cover (31), a second support block (13) is provided between the edge and the outer wall of the second piston rod (17), a second ball socket (27) is provided on the second support block (13), and a space for accommodating the second steel ball (18) is formed between the second ball socket (7) and the edge of the second locking block (12); Within the sliding stroke of the second piston (10), an oil groove is also provided on the inner wall of the second piston (10) and / or the outer wall of the second piston rod (17), so that the side wall oil passage (24) remains connected within the sliding stroke of the second piston (10).

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