Lifting oil cylinder with two mechanically locked ends

Abstract

The utility model discloses a lifting oil cylinder with the two ends mechanically locked. The lifting oil cylinder comprises a cylinder body, a piston rod, a piston and two locking assemblies arranged at the two ends in the cylinder body. Two ends of the piston are respectively provided with an annular structure body for accommodating a plurality of steel balls; the locking assembly comprises a sliding sleeve, a steel ball, a limiting sleeve and a reset spring, the limiting sleeve is fixed to the cylinder body, and an annular groove is formed in the inner surface of the limiting sleeve. When the locking assembly is in a locking state, the annular structural body is located between the sliding sleeve and the radial direction of the annular groove, and the steel ball penetrates through the annular structural body to be embedded into the annular groove. When the locking assembly is unlocked, the sliding sleeve extrudes towards the direction of the reset spring until the sliding sleeve and the annular groove are staggered. According to the utility model, the locking failure caused by power failure, no oil or pipeline fracture can be avoided, and the shaking of the lifted equipment caused by the up-down floating phenomenon due to the unstable state of the lifting oil cylinder at the falling moment can also be avoided.

Description

Technical Field

[0001] This utility model relates to the field of hydraulic cylinder design technology, and in particular to a lifting hydraulic cylinder with mechanical locking at both ends. Background Technology

[0002] Vehicle lifting cylinders generally use hydraulic locking devices to achieve lifting and locking. Due to the large number of hydraulic circuits, the locking function is easily lost during long-term lifting operations in the event of power failure, lack of oil, or pipeline rupture. To address this, the applicant previously proposed a lifting cylinder with mechanical locking (application number CN202420846180.4), but the published patent still has the following problems:

[0003] (1) The mechanical locking structure is only set at one end of the oil cylinder and has a locking function only in the lifting state. It does not have a locking function when the piston rod is fully retracted. If it relies solely on the action of hydraulic oil, there may be an instantaneous instability in the piston rod return position.

[0004] (2) The cavity where the spring used to unlock the mechanical locking structure is located is not connected to the cavity where the hydraulic oil is located. The spring needs to compress the air inside the cavity to retract. The larger the spring size, the larger the space in the cavity where the spring is located, which increases the difficulty of spring retraction and easily causes unlocking failure. Utility Model Content

[0005] To address the technical problem that existing lifting cylinders lack mechanical locking during retraction, resulting in momentary instability in the piston rod's return position, this invention provides a lifting cylinder with mechanical locking at both ends to solve the aforementioned problem.

[0006] The technical solution adopted by this utility model to solve its technical problem is: a lifting cylinder with mechanical locking at both ends, including a cylinder body, a piston rod, a piston, and two locking assemblies disposed at both ends inside the cylinder body; the piston has an annular structure at both ends that accommodates a number of steel balls; the locking assembly includes a sliding sleeve, steel balls, a limiting sleeve, and a return spring, the limiting sleeve is fixed to the cylinder body, the inner surface of the limiting sleeve has an annular groove, the sliding sleeve is slidably connected inside the limiting sleeve, and the return spring abuts against the sliding sleeve and the cylinder body along the axial direction.

[0007] When the locking assembly is in the locked state, the annular structure is located radially between the sliding sleeve and the annular groove, and the steel ball passes through the annular structure and is embedded in the annular groove; when the locking assembly is unlocked, the sliding sleeve is pressed towards the return spring until the sliding sleeve and the annular groove are misaligned.

[0008] In an optional embodiment of this utility model, the surface of the annular structure has a plurality of through holes for the steel ball to pass through. The radial distance between the annular structure and the piston rod is greater than the thickness of the sliding sleeve and less than the diameter of the steel ball, so that the sliding sleeve can extend into the inner side of the annular structure and lift the steel ball.

[0009] In an optional embodiment of this utility model, the cylinder body includes a cylinder barrel and a cylinder bottom sealed at one end of the cylinder barrel, the piston rod extends from the other end of the cylinder barrel, a locking assembly located on one side of the cylinder bottom is connected to the cylinder bottom, and a locking assembly located at the other end of the cylinder barrel is sleeved on the piston rod.

[0010] In an optional embodiment of this utility model, the sliding sleeve located on one side of the cylinder bottom has a radially inwardly protruding shoulder. A hydraulic cavity communicating with the outside and a reset cavity accommodating a reset spring are respectively formed on both sides of the shoulder. The center of the shoulder has a central pressure relief hole. The inner diameter of the hydraulic cavity and the reset cavity is larger than the diameter of the central pressure relief hole.

[0011] In an optional embodiment of this utility model, the limiting sleeve and the sliding sleeve have a flow gap that connects to the annular groove, the limiting sleeve has an oil hole that connects the flow gap to the outside, and the surface of the limiting sleeve has several flow channels that connect the flow gap to the hydraulic cavity.

[0012] In an optional embodiment of this utility model, the end of the sliding sleeve facing the piston has a locking tongue that extends into the inner side of the annular structure and a limiting end face that abuts against the end face of the piston rod.

[0013] In an optional embodiment of this utility model, the end of the locking tongue facing the piston has a ramp, and the inclination angle between the ramp and the piston rod axis is 30°~45°.

[0014] In an optional embodiment of this utility model, the end of the piston facing the locking tongue has an inclined surface that cooperates with the ramp, and the outer diameter of the inclined surface is smaller than the outer diameter of the ramp.

[0015] The beneficial effects of this utility model are:

[0016] (1) The present invention has locking components at both ends of the cylinder body. When the lifting cylinder is raised or retracted, it can be locked. This not only avoids locking failure due to power failure, lack of oil or pipeline rupture, but also avoids the unstable state of the lifting cylinder when it falls, resulting in up-and-down floating phenomenon and causing the lifted equipment to shake.

[0017] (2) The present invention provides a hydraulic chamber in the sliding sleeve at the bottom of the cylinder for pressing the return spring, and the hydraulic chamber is connected to the return chamber where the return spring is located, which helps to quickly compress the return spring and make the cylinder lock quickly. Attached Figure Description

[0018] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0019] Figure 1 This is an axial sectional view of a specific embodiment of the lifting cylinder with mechanical locking at both ends described in this utility model;

[0020] Figure 2 yes Figure 1 Enlarged view of point a in the middle;

[0021] Figure 3 yes Figure 1 Enlarged view at point b in the middle;

[0022] Figure 4 yes Figure 2 Enlarged view at point c;

[0023] Figure 5 yes Figure 1 A sectional view along the AA direction.

[0024] In the diagram, 1. Cylinder body, 101. Cylinder barrel, 102. Cylinder bottom, 2. Piston rod, 3. Piston, 4. Steel ball, 5. Annular structure, 501. Through hole, 6. Sliding sleeve, 601. Locking tongue, 602. Limiting end face, 7. Limiting sleeve, 701. Annular groove, 8. Return spring, 9. Retaining sleeve, 10. Annular retaining ring, 11. Ramp, 12. Inclined surface, 13. Returning cavity, 14. Shoulder, 1401. Central pressure relief hole, 15. Hydraulic cavity, 16. Flow gap, 17. Oil hole, 18. Flow channel. Detailed Implementation

[0025] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0026] Example 1

[0027] like Figures 1-5 As shown, a lifting cylinder with mechanical locking at both ends includes a cylinder body 1, a piston rod 2, a piston 3, and two locking assemblies disposed at both ends inside the cylinder body 1; the piston 3 has annular structures 5 at both ends that accommodate a plurality of steel balls 4; the locking assembly includes a sliding sleeve 6, steel balls 4, a limiting sleeve 7, and a return spring 8. The limiting sleeve 7 is fixed to the cylinder body 1, and the inner surface of the limiting sleeve 7 has an annular groove 701. The sliding sleeve 6 is slidably connected inside the limiting sleeve 7, and the return spring 8 abuts against the sliding sleeve 6 and the cylinder body 1 along the axial direction.

[0028] When the locking assembly is in the locked state, the annular structure 5 is located radially between the sliding sleeve 6 and the annular groove 701, and the steel ball 4 passes through the annular structure 5 and is embedded in the annular groove 701; when the locking assembly is unlocked, the sliding sleeve 6 is pressed towards the return spring 8 until the sliding sleeve 6 is misaligned with the annular groove 701.

[0029] One locking assembly is provided at each end of the cylinder body 1, and a ring of steel balls 4 is provided at each end of the piston 3. This allows the piston rod 2 to be locked at both ends of its stroke. When the lifting cylinder is in the lifting state, the piston rod 2 is locked by the locking assembly located at the outlet of the cylinder body 1 to prevent the lifting failure caused by the disappearance of external hydraulic pressure. When the piston rod 2 of the lifting cylinder falls back, the locking assembly at the bottom of the cylinder body 1 can lock the piston rod 2 instantly to prevent the piston rod 2 from floating up and down due to unstable hydraulic pressure, thereby causing the lifted equipment to shake.

[0030] Under normal conditions, the sliding sleeve 6 is positioned inside the annular groove 701 by the pushing action of the return spring 8. In the locked state, the steel ball 4 is pushed into the annular groove 701 of the limiting sleeve 7 by the sliding sleeve 6. The annular groove 701 restricts the axial movement of the steel ball 4. Since the steel ball 4 is located inside the annular structure 5, it also restricts the axial movement of the piston 3 and piston rod 2, which are located in the annular structure 5, thus locking the piston rod 2. When unlocking is required, an external force is applied to the sliding sleeve 6 in the direction of the return spring 8, causing the sliding sleeve 6 to displace from the annular groove 701, i.e., the sliding sleeve 6 leaves the annular structure 5. At this time, the steel ball 4 leaves the annular groove 701 and falls back into the piston 3. The axial restriction of the steel ball 4 by the annular groove 701 is removed, and the piston 3 and piston rod 2 can move axially.

[0031] The cross-section of the annular groove 701 is arc-shaped, which can wrap around part of the surface of the steel ball 4 and play an axial limiting role for the steel ball 4.

[0032] The cylinder block 1 typically includes a cylinder barrel 101 and a cylinder bottom 102 that seals one end of the cylinder barrel 101. The cylinder barrel 101 is an axially continuous cylindrical structure. The piston rod 2 extends from the other end of the cylinder barrel 101. A locking assembly located on one side of the cylinder bottom 102 is connected to the cylinder bottom 102, and a locking assembly located at the other end of the cylinder barrel 101 is fitted over the piston rod 2. The distance between the two locking assemblies is the stroke of the piston rod 2.

[0033] Ring structure 5:

[0034] like Figure 2 and Figure 5As shown, the annular structure 5 is similar to the annular groove 701, and is also a groove structure for accommodating the steel ball 4. The surface of the annular structure 5 has several through holes 501 for the steel ball 4 to pass through. The radial distance between the annular structure 5 and the piston rod 2 is greater than the thickness of the sliding sleeve 6 and less than the diameter of the steel ball 4, so that the sliding sleeve 6 can extend into the inner side of the annular structure 5 and lift the steel ball 4. Whether in the unlocked state or the locked state, each steel ball 4 rolls and rotates in its respective through hole 501.

[0035] like Figure 2 As shown, taking the annular structure 5 located at the left end of the piston 3 as an example, the right end of the annular structure 5 is spliced ​​with the piston 3 as one piece. The end of the piston 3 closes the gap between the right end of the annular structure 5 and the piston rod 2, while the left end of the annular structure 5 and the piston rod 2 are left with a gap for the locking assembly at the outlet of the cylinder 101 to be inserted and fitted.

[0036] During the reciprocating motion of the piston 3, the steel ball 4 rolls inside the annular structure 5. The steel ball 4 is located radially between the piston rod 2 and the cylinder 101. In order to avoid the frequent friction of the steel ball 4 with the piston rod 2 and cause wear to the piston rod 2, a retaining sleeve 9 is provided on the outer surface of the piston rod 2 in this embodiment. The retaining sleeve 9 is pressed against the end of the piston 3 by the annular retaining ring 10. The steel ball 4 is located on the outer surface of the retaining sleeve 9 and is in direct contact with the retaining sleeve 9.

[0037] Sliding sleeve 6:

[0038] The sliding sleeve 6 has a locking tongue 601 extending into the inner side of the annular structure 5 and a limiting end face 602 that abuts against the end face of the piston rod 2, such as... Figure 4 As shown. When the piston rod 2 approaches the sliding sleeve 6 and the locking tongue 601 extends into the annular structure 5, the limiting end face 602 can limit the movement of the piston rod 2. When the limiting end face 602 abuts against the piston rod 2, the steel ball 4 is also inserted into the annular groove 701. The locking assembly locks instantly and will not cause locking failure due to excessive movement.

[0039] Since the locking tongue 601 needs to press the steel ball 4 against the outer surface of the locking tongue 601 after being inserted into the annular structure 5, to avoid movement jamming or pressing failure, it is preferable to provide a ramp 11 at the end of the locking tongue 601 facing the piston 3. The ramp 11 can guide the steel ball 4 to move towards the outer surface of the locking tongue 601. If the slope of the ramp 11 is too large, the guiding effect will be poor; if the slope of the ramp 11 is too small, there may not be enough length of the ramp 11 to guide the steel ball 4 to the outer surface of the locking tongue 601. In this embodiment, the inclination angle between the ramp 11 and the piston rod 2 is 30°~45°. In a further design, the end of the piston 3 facing the locking tongue 601 has a slope 12 that cooperates with the ramp 11, and the outer diameter of the slope 12 is smaller than the outer diameter of the ramp 11. Figure 4As shown, the design of the inclined surface 12 can prevent the ramp 11 from hitting the end face of the piston 3, so that the locking tongue 601 and the piston 3 fit well. The height of the inclined surface 12 is less than the height of the ramp 11, and the inclined surface 12 can extend to the inside of the annular groove 701.

[0040] Example 2

[0041] The larger the diameter of the return spring 8 in the locking assembly, the better its elasticity and the better the locking effect. At the outlet end of the cylinder body 1, because the piston rod 2 needs to occupy axial space, the installation space for the return spring 8 is limited. Typically, a smaller diameter return spring 8 is arranged between the piston rod 2 and the radial clearance of the cylinder barrel 101. However, the locking assembly at one end of the cylinder bottom 102 can occupy the bottom space of the cylinder bottom 102 independently. Therefore, the return spring 8 here can be designed to be thicker. When the piston rod 2 falls back, the return spring 8 can withstand the impact force of the piston rod 2 falling back, keeping the sliding sleeve 6 in the extended state, thus achieving rapid locking of the hydraulic cylinder. Figure 2 As shown, a reset cavity 13 for accommodating a reset spring 8 is provided in the sliding sleeve 6 at one end of the cylinder bottom 102.

[0042] Example 3

[0043] Based on Embodiment 2, the sliding sleeve 6 located on one side of the cylinder bottom 102 has a radially inward protruding shoulder 14 inside. On both sides of the shoulder 14, a hydraulic cavity 15 communicating with the outside and a reset cavity 13 accommodating the reset spring 8 are formed respectively. The center of the shoulder 14 has a central pressure relief hole 1401. The inner diameter of the hydraulic cavity 15 and the reset cavity 13 is larger than the diameter of the central pressure relief hole 1401.

[0044] The movement of the sliding sleeve 6 can be driven by electricity or hydraulically. It is usually driven by the hydraulic oil that drives the piston rod 2. For example, when the sliding sleeve 6 is located at the outlet of the cylinder 101, it is pushed to the left when oil enters the rod chamber. After the locking component at the outlet is unlocked, the piston rod 2 moves back to the right. Similarly, when the sliding sleeve 6 is located at one end of the cylinder bottom 102, it is pushed towards the cylinder bottom 102 when oil enters the rodless chamber. After the locking component at the cylinder bottom 102 is unlocked, the piston rod 2 is lifted.

[0045] The hydraulic chamber 15 can increase the space of the rodless chamber, providing a larger initial force for the lifting of the piston rod 2, and can also provide a larger hydraulic pressure to compress the return spring 8. After connecting the hydraulic chamber 15 with the return chamber 13, a small amount of hydraulic oil can enter the return chamber 13, thereby avoiding the difficulty of the return spring 8 to contract due to the inability of air to be discharged from the return chamber 13, which would result in a large unlocking difficulty or even unlocking failure.

[0046] In a further design, a flow gap 16 is provided between the limiting sleeve 7 and the sliding sleeve 6, connecting to the annular groove 701. This flow gap 16 is the rodless cavity. The limiting sleeve 7 has an oil hole 17 connecting the flow gap 16 to the outside. The surface of the limiting sleeve 7 has several flow channels 18 connecting the flow gap 16 to the hydraulic cavity 15. Hydraulic oil enters from the oil inlet on the cylinder 101 and passes through the oil hole 17 into the flow gap 16. At the same time, some hydraulic oil enters the hydraulic cavity 15 through the flow channels 18.

[0047] Working process: In the initial state, the piston rod 2 is in the retracted state and abuts against the sliding sleeve 6 at the cylinder bottom 102. The locking component at the cylinder bottom 102 is in the locked state. When it is necessary to lift the cylinder, oil enters the rodless chamber and the hydraulic oil enters the hydraulic chamber 15 to unlock the locking component. At this time, the piston rod 2 extends outward from the cylinder 101. When the piston rod 2 reaches the highest point of its stroke, the steel ball 4 located at the outer end of the piston 3 cooperates with the locking component at the outlet of the cylinder 101 to lock it, keeping the piston rod 2 in the lifted state. When it is necessary to retract the piston rod 2, oil enters the rod chamber and the hydraulic oil pushes the sliding sleeve 6 at the outlet to move, unlocking the locking component and allowing the piston rod 2 to fall freely.

[0048] In the description of this utility model, it should be understood that the terms "center", "left", "right", "top", "bottom", "inner", "outer", "axial", "radial", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0049] In this specification, the illustrative expressions of the terms do not necessarily refer to the same embodiments. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments.

[0050] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A mechanically locked at both ends lifting ram, characterized in that: The cylinder, the piston rod, the piston and two locking assemblies arranged at both ends of the cylinder; The two ends of the piston are respectively provided with annular structures containing a plurality of steel balls; The locking assembly comprises a sliding sleeve, a steel ball, a limiting sleeve and a return spring, the limiting sleeve is fixed to the cylinder, the inner surface of the limiting sleeve is provided with an annular groove, the sliding sleeve is slidably connected to the inside of the limiting sleeve, and the return spring abuts between the sliding sleeve and the cylinder in the axial direction; When the locking assembly is in the locked state, the annular structure is located between the sliding sleeve and the radial direction of the annular groove, and the steel ball is embedded in the annular groove through the annular structure; when the locking assembly is unlocked, the sliding sleeve is extruded towards the return spring until the sliding sleeve is disengaged from the annular groove.

2. The mechanical lock both ends of lift cylinder according to claim 1, characterized in that: The surface of the annular structure is provided with a plurality of through holes for the steel balls to pass through, the radial distance between the annular structure and the piston rod is greater than the thickness of the sliding sleeve and less than the diameter of the steel ball, so that the sliding sleeve can extend into the inside of the annular structure and lift the steel ball.

3. The mechanical lock both ends of lift cylinder of claim 1, wherein: The cylinder comprises a cylinder barrel and a cylinder bottom sealed at one end of the cylinder barrel, the piston rod extends from the other end of the cylinder barrel, the locking assembly on one side of the cylinder bottom is connected to the cylinder bottom, and the locking assembly on the other end of the cylinder barrel is sleeved on the piston rod.

4. The mechanical lock both ends of the lift cylinder of claim 3, characterized in that: The inside of the sliding sleeve on one side of the cylinder bottom is provided with a shoulder protruding radially inward, the two sides of the shoulder are respectively formed with a hydraulic chamber and a reset chamber for accommodating the return spring, the center of the shoulder is provided with a center relief hole, and the inner diameters of the hydraulic chamber and the reset chamber are greater than the hole diameter of the center relief hole.

5. The mechanical lock both ends of lift cylinder according to claim 4, characterized in that: The limiting sleeve and the sliding sleeve are provided with a flow gap communicated to the annular groove, the limiting sleeve is provided with an oil hole communicated between the flow gap and the outside, and the surface of the limiting sleeve is provided with a plurality of flow channels communicated between the flow gap and the hydraulic chamber.

6. The double-acting mechanical lock lift ram as described in claim 2, wherein: The end of the sliding sleeve towards the piston is provided with a locking tongue extending into the inside of the annular structure and a limiting end face abutting against the end face of the piston rod.

7. The mechanical lock both ends of lift cylinder according to claim 6, characterized in that: The end of the locking tongue towards the piston is provided with a slope, and the inclination angle of the slope with respect to the axial direction of the piston rod is 30°-45°.

8. The mechanical lock both ends of lift cylinder according to claim 7, characterized in that: The end of the piston towards the locking tongue is provided with a bevel matched with the slope, and the outer diameter of the bevel is smaller than the outer diameter of the slope.

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