Full-extending mechanical self-locking lifting oil cylinder

Abstract

The invention relates to the technical field of lifting oil cylinders, in particular to a full-extension mechanical self-locking lifting oil cylinder which comprises a cylinder barrel, a cylinder head is detachably connected to the open end of the cylinder barrel, a self-locking cover is detachably connected to the outer side surface of the cylinder head, a piston is movably connected to the interior of the cylinder barrel, a cylinder rod is coaxially and fixedly connected to the axis of the piston, and the self-locking cover is detachably connected to the outer side surface of the cylinder head. The cylinder rod movably penetrates through the cylinder head and a center hole of the self-locking cover, a locking round head is movably connected into the self-locking cover, a locking round groove allowing the locking round head to be embedded is formed in the surface of the cylinder rod in a matched mode, and the locking round head locks the cylinder rod by being embedded into the locking round groove. The invention aims to solve the problems that a traditional lifting oil cylinder mainly depends on continuous pressure of a hydraulic system to maintain a supporting state, and when the conditions of sealing piece aging, pipeline damage and the like occur in the hydraulic system, hydraulic oil leakage is likely to occur, so that a cylinder rod falls back due to load dead weight, and equipment is out of control or potential safety hazards are caused.

Description

Technical Field

[0001] The present invention relates to the technical field of lifting cylinders, and specifically to a fully extended mechanical self-locking lifting cylinder. Background Art

[0002] As a key actuator in the field of mechanical engineering, the core structure of a lifting cylinder consists of a cylinder barrel, a piston rod, a piston assembly, a sealing device, etc. It achieves precise lifting operations through the pressure transmission of a hydraulic system. The working principle of this device is based on Pascal's law. When a hydraulic pump injects high-pressure oil into the cylinder barrel, the pressure acts on the piston surface, pushing the piston rod to perform linear reciprocating motion, thereby converting hydraulic energy into mechanical energy to complete the vertical lifting or lowering operation of the load. Its significant advantage is that it can provide stable lifting force, with load-bearing capacities ranging from several hundred kilograms to dozens of tons, and the lifting and lowering speed and positioning accuracy can be precisely adjusted through a control valve group.

[0003] In the field of construction machinery, lifting cylinders are core functional components of equipment such as loaders, excavators, and cranes. For example, the boom lifting system of a loader relies on cylinders to achieve the shoveling and unloading of materials, and the luffing mechanism of a crane adjusts the boom angle through cylinders to meet different lifting requirements. In industrial equipment applications, lifting cylinders are widely used in the lifting platforms of automated production lines, the die lifting devices in die manufacturing, and the shelf loading and unloading equipment in warehousing and logistics, and can meet the working conditions requirements of high-precision positioning and frequent start-stop. By selecting high-strength materials and special surface treatment processes, it can effectively resist the influence of complex working conditions such as dust, humidity, and heavy loads, and thus plays an irreplaceable role in heavy equipment in industries such as metallurgy, chemical industry, and construction.

[0004] The working mechanism of traditional lifting cylinders relies on the dynamic balance of the hydraulic system. The maintenance of its supporting state is essentially a continuous coupling process of hydraulic energy and mechanical energy. After the cylinder completes the lifting action, a pressure-holding circuit is required to form a constant pressure difference on both sides of the piston to offset the load gravity. However, this design that relies on continuous hydraulic support will cause the sealing lip to wear or deform due to material aging under long-term high-pressure working conditions, and metal pipelines may develop cracks due to vibration fatigue and corrosion erosion, especially in areas with stress concentration at joint welds or bends, where leakage points are likely to form. When hydraulic oil leakage occurs, the pressure in the upper or lower chamber of the cylinder will gradually decay as the leakage amount accumulates, breaking the original pressure balance state. This failure mode is particularly dangerous in scenarios such as aerial work platforms in construction machinery and the luffing mechanisms of truck cranes. The boom may quickly fall back due to its own weight, causing the cargo to fall or the equipment to overturn. The sealing failure of the cylinder of an industrial lifting platform may cause the platform to suddenly sink, threatening the safety of operators. Summary of the Invention

[0005] The object of the present invention is to provide a fully extended mechanical self-locking lifting oil cylinder, so as to solve the problem that the traditional lifting oil cylinder mainly relies on the continuous pressure of the hydraulic system to maintain the supporting state. When the hydraulic system has problems such as seal aging and pipeline damage, hydraulic oil leakage is likely to occur, resulting in the cylinder rod falling back due to the load self-weight, leading to equipment out of control or safety hazards.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A fully extended mechanical self-locking lifting oil cylinder, including a cylinder barrel, the open end of the cylinder barrel is detachably connected with a cylinder head, the outer surface of the cylinder head is detachably connected with a self-locking cover, a piston is movably connected inside the cylinder barrel, a cylinder rod is coaxially and fixedly connected at the axis center of the piston, the cylinder rod movably penetrates through the central holes of the cylinder head and the self-locking cover, a locking round head is movably connected inside the self-locking cover, a locking round groove for the locking round head to be embedded is cooperatively provided on the surface of the cylinder rod, and the locking round head locks the cylinder rod by being embedded in the locking round groove.

[0008] Preferably, a connecting sleeve is sleeved on the surface of the cylinder rod, the connecting sleeve is located inside the cylinder barrel, a plugging round head is movably connected to the surface of the connecting sleeve, and the plugging round head is used for sealing the locking round groove.

[0009] Preferably, a channel for the plugging round head to move is provided on the surface of the connecting sleeve, and the channel is communicated with the inner cavity of the cylinder barrel.

[0010] Preferably, a retaining ring is fixedly connected to the inner surface of the cylinder head, and an annular gap with a width matching the thickness of the connecting sleeve is formed between the retaining ring and the outer wall of the cylinder rod.

[0011] Preferably, a limiting support rod is fixedly connected to the surface of the retaining ring, and its axial extension direction is parallel to the axis of the cylinder rod.

[0012] Preferably, an annular oil storage groove is provided at the bottom end of the locking round head.

[0013] Preferably, a limiting retaining ring is fixedly connected to the opening of the channel of the connecting sleeve.

[0014] Preferably, a threaded sleeve is rotatably connected to the surface of the self-locking cover, one end of the locking round head is rotatably connected with a threaded rod, and the threaded sleeve is coaxially and threadedly sleeved on the surface of the threaded rod.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. Through the rigid engagement of the locking round head and the locking round groove, mechanical locking is achieved in the fully extended state of the oil cylinder, replacing the simple hydraulic support. Even if the hydraulic system has leakage, pressure fluctuation or external force impact, it can still prevent the cylinder rod from falling back, ensure the stable position of the load, and avoid safety accidents;

[0017] 2. When the cylinder rod contracts, the plug round head automatically inserts into the locking round groove under the action of the hydraulic oil pressure, preventing the hydraulic oil from entering the groove and avoiding an increase in the insertion resistance of the locking round head or locking failure caused by the residual oil when extending again, ensuring the rigid engagement of the mechanical lock;

[0018] 3. The pressure relief ring blocks the high-pressure oil from entering the gap between the connecting sleeve and the cylinder head, ensuring that the connecting sleeve always clings to the end face of the cylinder head, avoiding misalignment of the plug round head and the locking round groove caused by free sliding, and ensuring the dynamic seal and alignment accuracy during the contraction process;

[0019] 4. The piston stroke is limited by the limit strut, preventing it from moving too far to the left and causing the volume of the left oil cavity to be too small, providing sufficient space for the hydraulic pressure to act on the plug round head, and ensuring the normal operation of the hydraulic system;

[0020] 5. The annular oil storage groove at the bottom of the locking round head can temporarily store a small amount of residual hydraulic oil in the locking round groove, avoiding the formation of a high-pressure oil film by the oil to hinder the mechanical lock, allowing the residual oil to be processed after work, and improving the fault tolerance of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of the overall cylinder rod of the present invention in the extended state;

[0022] Figure 2 is a schematic vertical sectional view of the overall cylinder barrel, cylinder head, and self-locking cover of the present invention;

[0023] Figure 3 is a front sectional view of the overall cylinder rod of the present invention in the extended state;

[0024] Figure 4 is the present invention Figure 3 an enlarged view of part A in;

[0025] Figure 5 is the present invention Figure 3 an enlarged view of part B in;

[0026] Figure 6 is a schematic structural diagram of the cylinder rod of the present invention;

[0027] Figure 7 is a schematic structural diagram of the pressure relief ring of the present invention;

[0028] Figure 8 is a vertical sectional view of the connecting sleeve of the present invention;

[0029] Figure 9 is a vertical sectional view of the locking round head of the present invention;

[0030] Figure 10 is a front sectional view of the overall cylinder rod of the present invention in the contracted state.

[0031] In the figure: 1, cylinder barrel; 2, cylinder head; 3, self-locking cover; 4, piston; 5, cylinder rod; 6, locking circular groove; 7, plug round head; 8, limit retaining ring; 9, connecting sleeve; 10, retaining ring with slot; 11, limit support rod; 12, locking round head; 13, annular oil storage groove; 14, threaded rod; 15, threaded sleeve; 16, first gear; 17, second gear; 18, motor. Specific implementation mode

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0033] Please refer to Figures 1 to 10 , the present invention provides a technical solution: a fully extended mechanical self-locking lifting oil cylinder, including a cylinder barrel 1, the open end of the cylinder barrel 1 is detachably connected with a cylinder head 2, the outer surface of the cylinder head 2 is detachably connected with a self-locking cover 3, both the cylinder head 2 and the self-locking cover 3 can be detachably connected by bolts, a piston 4 is movably connected inside the cylinder barrel 1, a cylinder rod 5 is coaxially and fixedly connected to the axis of the piston 4, the cylinder rod 5 movably penetrates through the central holes of the cylinder head 2 and the self-locking cover 3, a locking round head 12 is movably connected inside the self-locking cover 3, a locking circular groove 6 for the locking round head 12 to be embedded is cooperatively provided on the surface of the cylinder rod 5, and the locking round head 12 locks the cylinder rod 5 by being embedded in the locking circular groove 6. When the cylinder rod 5 extends out of the cylinder barrel 1, if the locking circular groove 6 moves to align with the locking round head 12, by pushing the locking round head 12 to make it embedded in the locking circular groove 6, the cylinder rod 5 can be mechanically locked. By replacing the simple hydraulic support with a mechanical locking structure, rigid fixation can be achieved in the fully extended state of the oil cylinder. The mechanical self-locking function can be used as a double insurance for the hydraulic system to avoid the cylinder rod 5 from falling back due to hydraulic system leakage, pressure fluctuation or external force impact, ensure the stable position of the load, and after locking, the hydraulic system can be unloaded, reducing the long-term pressure-bearing loss of the oil pump, prolonging the service life of hydraulic components, and at the same time reducing energy consumption.

[0034] A connecting sleeve 9 is sleeved on the surface of the cylinder rod 5. The connecting sleeve 9 is located inside the cylinder barrel 1. A plug round head 7 is movably connected to the surface of the connecting sleeve 9. The plug round head 7 is used to seal the locking round groove 6. When the cylinder rod 5 contracts, the locking round groove 6 moves into the cylinder barrel 1 along with the cylinder rod 5. Before entering the inside of the cylinder barrel 1, the locking round groove 6 first passes through the connecting sleeve 9. When the locking round groove 6 is aligned with the plug round head 7, at this time, due to the force, the plug round head 7 will be embedded into the locking round groove 6 to block the locking round groove 6. This structure can prevent the hydraulic oil in the cylinder barrel 1 from entering the locking round groove 6 when the locking round groove 6 moves in the cylinder barrel 1 along with the cylinder rod 5, ensuring that when the cylinder rod 5 extends again and the locking round groove 6 is aligned with the locking round head 12, there is no oil in the groove, so that the locking round head 12 can be reliably embedded into the groove, avoiding the increase of the embedding resistance and the locking failure caused by the existence of oil between the locking round head 12 and the locking round groove 6.

[0035] A channel for the plug round head 7 to move is provided on the surface of the connecting sleeve 9. The channel communicates with the inner cavity of the cylinder barrel 1, so that the non-embedded end of the tail of the plug round head 7 is exposed to the hydraulic oil in the cylinder barrel 1, and the head can be embedded into the locking round groove 6 on the surface of the cylinder rod 5. When the cylinder barrel 1 is filled with hydraulic oil, the oil pressure acts on the tail end face of the plug round head 7. When the cylinder rod 5 contracts and the locking round groove 6 moves to align with the plug round head 7, the plug round head 7 is automatically embedded into the locking round groove 6 under the drive of the hydraulic pressure to form a seal. The tail of the plug round head 7 is under the action of the hydraulic oil pressure in the cylinder barrel 1 and always maintains a thrust towards the axis direction of the cylinder rod 5, and makes the connecting sleeve 9 move in the cylinder barrel 1 along with the cylinder rod 5, ensuring that when the locking round groove 6 is in the cylinder barrel 1, the plug round head 7 always blocks the locking round groove 6. Without manual operation or additional spring mechanism, the automatic embedding of the plug round head 7 is realized by using the oil pressure of the system itself, reducing the mechanical complexity.

[0036] When the cylinder rod 5 needs to extend, high-pressure oil is injected into the right oil cavity of the piston 4, and the left oil cavity is depressurized. The piston 4 drives the cylinder rod 5 to move leftward under the action of the pressure difference. The connecting sleeve 9 moves synchronously with the cylinder rod 5 until the left end surface of the connecting sleeve 9 abuts against the right end surface of the cylinder head 2. At this time, the oil pressure in the left oil cavity of the piston 4 is further reduced, so that the hydraulic pressure acting on the tail of the plug round head 7 is reduced. The bottom of the locking round groove 6 is an inclined arc surface. When the cylinder rod 5 continues to move leftward under the continuous action of the oil pressure difference, the inclined surface of the locking round groove 6 will generate a radial thrust on the head of the plug round head 7, pressing the plug round head 7 back into the channel of the connecting sleeve 9. At this point, the connecting sleeve 9 stops moving because it abuts against the cylinder head 2, while the cylinder rod 5 continues to extend leftward. When the locking round groove 6 passes through the central hole of the cylinder head 2 and moves to be axially aligned with the locking round head 12 in the self-locking cover 3, a signal is applied to the driving mechanism of the locking round head 12 to make it radially embedded into the locking round groove 6, completing the mechanical locking of the fully extended state of the cylinder rod 5.

[0037] A gap ring 10 is fixedly connected to the inner surface of the cylinder head 2. An annular gap matching the thickness of the connecting sleeve 9 is formed between the outer wall of the gap ring 10 and the cylinder rod 5. When the connecting sleeve 9 moves leftward along with the cylinder rod 5 until the left end face of the connecting sleeve 9 abuts against the right end face of the cylinder head 2, the left side surface of the connecting sleeve 9 just fits into the annular gap between the gap ring 10 and the cylinder rod 5, that is, the left end face of the connecting sleeve 9 is blocked by the gap ring 10, and the rest of the gap ring 10 is exposed in the left oil chamber of the cylinder barrel 1. By providing the gap ring 10, when the cylinder rod 5 contracts, high-pressure oil is introduced into the left oil chamber and the right oil chamber is depressurized. Due to the blocking effect of the gap ring 10, the high-pressure oil cannot enter the gap between the left end face of the connecting sleeve 9 and the cylinder head 2, and can only act on the right part area of the connecting sleeve 9, generating a leftward pressure, so that the connecting sleeve 9 always closely adheres to the end face of the cylinder head 2. Until the cylinder rod 5 contracts to the position where the locking circular groove 6 is aligned with the blocking round head 7, the high-pressure oil in the left oil chamber acts on the tail of the blocking round head 7 through the channel of the connecting sleeve 9, driving it to embed into the locking circular groove 6. At this time, the cylinder rod 5 drives the connecting sleeve 9 to move rightward synchronously, realizing the dynamic seal during the contraction stroke. At the initial stage of the contraction of the cylinder rod 5, the connecting sleeve 9 is limited and closely adheres to the cylinder head 2 to prevent its free sliding from causing the blocking round head 7 to be inconvenient to align with the locking circular groove 6.

[0038] A limiting support rod 11 is fixedly connected to the surface of the gap ring 10, and its axial extension direction is parallel to the axis of the cylinder rod 5. By providing the limiting support rod 11, when the piston 4 drives the cylinder rod 5 to move leftward, when the piston 4 abuts against the right end of the limiting support rod 11, it stops moving, preventing the piston 4 from moving too far leftward, resulting in too small an oil chamber volume on the left side of the piston 4. This limiting distance ensures that there is enough volume in the oil chamber on the left side of the piston 4 to provide an effective hydraulic pressure acting space for the blocking round head 7.

[0039] An annular oil storage groove 13 is opened at the bottom end of the locking round head 12. The annular oil storage groove 13 plays a role in error tolerance. By opening the annular oil storage groove 13, when there is a small amount of hydraulic oil remaining in the locking circular groove 6, during the embedding process of the locking round head 12, the annular oil storage groove 13 can temporarily store the oil fluid, avoiding the formation of a high-pressure oil film between the contact surfaces and hindering the rigid bite of the mechanical lock. The small amount of oil in the locking circular groove 6 will be processed after the work is completed.

[0040] A limiting retaining ring 8 is fixedly connected to the opening of the channel of the connecting sleeve 9. The limiting retaining ring 8 is used to prevent the blocking round head 7 from moving out of the channel.

[0041] In an embodiment of controlling the movement of the locking round head 12, a threaded sleeve 15 is rotatably connected to the surface of the self-locking cover 3, and one end of the locking round head 12 is rotatably connected to a threaded rod 14. The threaded sleeve 15 is coaxially threadedly sleeved on the surface of the threaded rod 14. By controlling the rotation of the threaded sleeve 15, the threaded rod 14 axially moves under the action of the thread, driving the locking round head 12 to axially move, and controlling the locking round head 12 to penetrate into or move out of the locking circular groove 6.

[0042] The locking and unlocking processes can be achieved by manually rotating the threaded sleeve 15 or electrically driving the threaded sleeve 15. An embodiment of electrically driving the threaded sleeve 15 is that a motor 18 is fixedly installed on the surface of the self-locking cover 3. The output end of the motor 18 is coaxially and fixedly connected with a second gear 17. The surface of the threaded sleeve 15 is coaxially and fixedly connected with a first gear 16. The second gear 17 and the first gear 16 are meshed. By starting the motor 18 to drive the second gear 17 to rotate, the second gear 17 rotates to drive the first gear 16 to rotate, and the first gear 16 rotates to drive the threaded sleeve 15 to rotate.

[0043] Specifically, in the initial state: the cylinder rod 5 is in a contracted state, and the locking circular groove 6 is sealed by the plug round head 7.

[0044] Hydraulic drive extension: Inject high-pressure oil into the right oil chamber of the piston 4, and the left oil chamber is correspondingly depressurized synchronously. The piston 4 moves to the left under the action of the oil pressure difference, driving the cylinder rod 5 to extend synchronously. The connecting sleeve 9 moves together with the cylinder rod 5. When the left end surface of the connecting sleeve 9 abuts against the right end surface of the cylinder head 2, continue to increase the oil pressure in the right oil chamber, and the cylinder rod 5 continues to move to the left. At this time, the inclined bottom of the locking circular groove 6 generates a radial thrust on the plug round head 7, pressing it back into the channel of the connecting sleeve 9, releasing the seal of the locking circular groove 6. The cylinder rod 5 continues to extend. When the locking circular groove 6 moves axially aligned with the locking round head 12 in the self-locking cover 3, that is, when the cylinder rod 5 is in the fully extended state, stop injecting hydraulic oil, rotate the threaded sleeve 15 on the self-locking cover 3, and push the locking round head 12 radially into the locking circular groove 6 through the threaded rod 14. After the locking round head 12 is embedded, the cylinder rod 5 is rigidly fixed by the mechanical structure.

[0045] The contraction process of the cylinder rod 5: First, pressurize the hydraulic system to establish oil pressure in the left oil chamber of the piston 4, rotate the threaded sleeve 15 in the reverse direction to withdraw the locking round head 12 from the locking circular groove 6 and return it to the initial position in the self-locking cover 3. Inject high-pressure oil into the left oil chamber and depressurize the right oil chamber. The piston 4 moves to the right under the action of the oil pressure difference, driving the cylinder rod 5 to contract synchronously. When the locking circular groove 6 moves to align with the plug round head 7 in the connecting sleeve 9, the hydraulic pressure in the left oil chamber acts on the tail of the plug round head 7, driving it to embed into the locking circular groove 6 to seal the space in the groove and prevent hydraulic oil from entering the groove and affecting the next locking. Subsequently, the connecting sleeve 9 moves together with the cylinder rod 5.

[0046] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A fully extended mechanical self-locking lifting oil cylinder, comprising a cylinder barrel (1), characterized in that: The open end of the cylinder barrel (1) is detachably connected with a cylinder head (2), the outer surface of the cylinder head (2) is detachably connected with a self-locking cover (3), a piston (4) is movably connected inside the cylinder barrel (1), a cylinder rod (5) is coaxially and fixedly connected to the axis center of the piston (4), the cylinder rod (5) movably penetrates through the central holes of the cylinder head (2) and the self-locking cover (3), a locking round head (12) is movably connected inside the self-locking cover (3), a locking round groove (6) for the locking round head (12) to be embedded is formed by matching on the surface of the cylinder rod (5), and the cylinder rod (5) is locked by the locking round head (12) being embedded into the locking round groove (6).

2. The fully extended mechanical self-locking lifting oil cylinder according to claim 1, characterized in that, A connecting sleeve (9) is sleeved on the surface of the cylinder rod (5), the connecting sleeve (9) is located inside the cylinder barrel (1), a plugging round head (7) is movably connected to the surface of the connecting sleeve (9), and the plugging round head (7) is used for sealing the locking round groove (6).

3. A fully extended mechanical self-locking lifting oil cylinder according to claim 2, characterized in that, A channel for the plugging round head (7) to move is formed on the surface of the connecting sleeve (9), and the channel is communicated with the inner cavity of the cylinder barrel (1).

4. A fully extended mechanical self-locking lifting oil cylinder according to claim 2, characterized in that, A retaining ring (10) is fixedly connected to the inner surface of the cylinder head (2), and an annular gap with a width matching the thickness of the connecting sleeve (9) is formed between the retaining ring (10) and the outer wall of the cylinder rod (5).

5. The fully extended mechanical self-locking lifting oil cylinder according to claim 4, characterized in that, A limiting strut (11) is fixedly connected to the surface of the retaining ring (10), and the axial extension direction thereof is parallel to the axis of the cylinder rod (5).

6. A fully extended mechanical self-locking lifting oil cylinder according to claim 1, characterized in that, An annular oil storage groove (13) is formed at the bottom end of the locking round head (12).

7. A fully extended mechanical self-locking lifting oil cylinder according to claim 2, characterized in that, A limiting retaining ring (8) is fixedly connected to the opening of the channel of the connecting sleeve (9).

8. A fully extended mechanically self-locking lifting oil cylinder according to claim 1, characterized in that, A threaded sleeve (15) is rotatably connected to the surface of the self-locking cover (3), one end of the locking round head (12) is rotatably connected with a threaded rod (14), and the threaded sleeve (15) is coaxially threadedly sleeved on the surface of the threaded rod (14).

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