1. A hydraulic cylinder comprises a cylinder barrel (1), a cylinder head assembly (2), a piston rod assembly (3) and a piston assembly (4), and is characterized in that the piston assembly (4) comprises a piston (41), a piston step structure (411) is formed on the inner wall of the piston (41), the piston rod assembly (3) comprises a piston rod (31) and a piston press-fitting part (32), a piston press-fitting part connecting part (311) is arranged at the end part of one end of the piston rod (31), the piston (41) is sleeved on the piston rod (31), the piston press-fitting part (32) is connected with the piston press-fitting part connecting part (311), and the piston step structure (411) can be abutted against the piston rod (31); the cylinder head assembly (2) comprises a guide sleeve (21) and a guide sleeve pressing piece (22), a guide sleeve step structure (211) is formed on the outer wall of the guide sleeve (21), a guide sleeve pressing piece connecting portion (11) is arranged on the inner wall of the cylinder barrel at the cylinder head of the cylinder barrel (1), the guide sleeve (21) is sleeved in the cylinder barrel (1), and the guide sleeve pressing piece (22) is connected with the guide sleeve pressing piece connecting portion (11) and can abut against the guide sleeve step structure (211) at the cylinder head of the cylinder barrel (1).

2. The hydraulic cylinder according to claim 1, wherein the piston press-fitting part (32) is a compression nut, a piston rod step structure (312) for receiving the piston step structure (411) is formed at the joint of the piston press-fitting part connecting part (311) and the piston rod (31), a threaded structure is arranged on the outer wall of the piston press-fitting part connecting part (311), a threaded connecting hole is formed in the middle of the compression nut, and the compression nut can be connected with the piston rod (31) through the matching of the threaded connecting hole and the threaded structure.

3. Hydraulic cylinder according to claim 2, wherein a plurality of set screws (5) are arranged between the gland nut and the piston press fitting connection (311).

4. The high-tightness hydraulic cylinder as claimed in any one of claims 1 to 3, wherein a plurality of piston outer wall groove structures capable of accommodating sealing members (6) are further arranged on the outer wall of the piston (41) which is in contact with the inner wall of the cylinder barrel; the part of the inner wall of the piston (41) which is in contact with the piston rod (31) is provided with a piston inner wall groove structure which can accommodate the sealing element (6).

5. The hydraulic cylinder according to claim 4, wherein the sealing elements (6) in the inner piston wall groove structure are O-ring seals, and the number of the outer piston wall groove structures is at least 5, and the sealing elements comprise a first outer piston wall groove structure, a second outer piston wall groove structure, a third outer piston wall groove structure, a fourth outer piston wall groove structure and a fifth outer piston wall groove structure, which are arranged in sequence from the cylinder bottom to the cylinder head, wherein the sealing elements (6) in the first outer piston wall groove structure and the fifth outer piston wall groove structure are O-ring seals, the sealing elements (6) in the second outer piston wall groove structure and the fourth outer piston wall groove structure are O-ring retainers, and the sealing elements (6) in the third outer piston wall groove structure are step combination sealing rings.

6. The hydraulic cylinder according to claim 5, characterized in that a travel limit plug (42) is further sleeved on the piston rod (31), the travel limit plug (42) is arranged between the piston (41) and the guide sleeve (21), and one end of the travel limit plug is in contact with the piston (41); the part, which is in contact with the piston rod (31), of the stroke limiting plug (42) is provided with a limiting plug groove structure capable of accommodating the sealing element (6), and the sealing element (6) in the limiting plug groove structure is an O-shaped ring retainer ring.

7. Hydraulic cylinder according to claim 6, characterized in that the guide housing outer wall is provided with at least one guide housing outer wall groove structure capable of accommodating the seal (6) at a portion of the guide housing outer wall in contact with the cylinder barrel (1), and the guide housing (21) is provided with at least one guide housing inner wall groove structure capable of accommodating the seal (6) at an inner wall thereof.

8. Hydraulic cylinder according to claim 7, wherein the guide sleeve outer wall groove structures are provided in two and the sealing elements (6) in both guide sleeve outer wall groove structures are O-ring seals; the guide sleeve inner wall groove structure is set to be 5, and comprises a first guide sleeve inner wall groove structure, a second guide sleeve inner wall groove structure, a third guide sleeve inner wall groove structure, a fourth guide sleeve inner wall groove structure and a fifth guide sleeve inner wall groove structure which are sequentially arranged from the cylinder bottom to the cylinder head, wherein the sealing element (6) in the first guide sleeve inner wall groove structure and the third guide sleeve inner wall groove structure is an O-shaped ring retainer ring, the sealing element (6) in the second guide sleeve inner wall groove structure is a stepped combined sealing ring, the sealing element (6) in the fourth guide sleeve inner wall groove structure is a U-shaped sealing element, and the sealing element (6) in the fifth guide sleeve inner wall groove structure is a dust ring.

9. The hydraulic cylinder according to claim 8, wherein the guide bushing press-fit part connecting part (11) is capable of forming with the inner wall of the cylinder a cylinder step structure (12) for receiving the guide bushing step structure (211), and wherein an internal thread structure is provided on the guide bushing press-fit part connecting part (11), and wherein the guide bushing press-fit part (22) is connected to the cylinder (1) by means of the cooperation of the external thread structure on the outer wall thereof and the internal thread structure.

10. A lifting device, characterized in that it comprises a hydraulic cylinder according to any one of claims 1 to 9.

Background

The hydraulic oil cylinder is a key element of the crane and has the function of driving a load or an actuating mechanism to act by the telescopic motion of a piston rod in a cylinder barrel.

The hydraulic cylinder needs to be guaranteed to have good sealing performance so as to prevent leakage of hydraulic oil, and the hydraulic cylinder needs to be guaranteed not to be subjected to cavity crossing so as to guarantee the working stability of the hydraulic cylinder.

In the hydraulic cylinder in the prior art, or a sealing gap exists between the guide sleeve and the cylinder barrel, so that the sealing performance is poor, the guide sleeve generates axial displacement in the working process of the hydraulic cylinder, the structure of the cylinder head of the hydraulic cylinder is easy to damage, the integral sealing failure of the hydraulic cylinder is finally caused, and hydraulic oil leaks; or the sealing element on the piston is easy to distort and deform in the installation and connection process of the piston and the piston rod, so that the sealing failure is caused, the hydraulic cylinder is connected with the cavity in series, and the working stability of the hydraulic cylinder is seriously influenced.

In view of the above, a hydraulic cylinder is needed.

Disclosure of Invention

The technical problem to be solved by the first aspect of the present invention is to provide a hydraulic cylinder, which has good sealing performance and is not easy to form cavities.

In addition, the technical problem to be solved by the second aspect of the present invention is to provide a hoisting device which has good working stability and high safety.

In order to achieve the above object, a first aspect of the present invention provides a hydraulic cylinder, including a cylinder barrel, a cylinder head assembly, a piston rod assembly and a piston assembly, where the piston assembly includes a piston, a piston step structure is formed on an inner wall of the piston, the piston rod assembly includes a piston rod and a piston press-fitting part, an end of one end of the piston rod is provided with a piston press-fitting part connecting part, the piston is sleeved on the piston rod, the piston press-fitting part is connected with the piston press-fitting part connecting part, and the piston step structure can be abutted and fixed on the piston rod; the cylinder head assembly comprises a guide sleeve and a guide sleeve pressing piece, a guide sleeve step structure is formed on the outer wall of the guide sleeve, a guide sleeve pressing piece connecting portion is arranged on the inner wall of the cylinder barrel at the cylinder barrel cylinder head, the guide sleeve is sleeved in the cylinder barrel, and the guide sleeve pressing piece is connected with the guide sleeve pressing piece connecting portion and can be abutted against the guide sleeve step structure at the cylinder head of the cylinder barrel.

Preferably, the piston press fitting part is a compression nut, a piston rod step structure for receiving the piston step structure is formed at the joint of the piston press fitting part connecting part and the piston rod, a threaded structure is arranged on the outer wall of the piston press fitting part connecting part, a threaded connecting hole is formed in the middle of the compression nut, and the compression nut can be connected with the piston rod through the matching of the threaded connecting hole and the threaded structure.

Further preferably, a plurality of set screws are arranged between the compression nut and the connecting part of the piston press-fitting part.

Further preferably, the outer wall of the piston, which is in contact with the inner wall of the cylinder barrel, is also provided with a plurality of piston outer wall groove structures capable of accommodating the sealing elements; and the part of the inner wall of the piston, which is in contact with the piston rod, is provided with a piston inner wall groove structure capable of accommodating the sealing element.

Further preferably, the sealing elements in the groove structures on the inner wall of the piston are O-shaped sealing rings, the groove structures on the outer wall of the piston are at least 5, and the groove structures on the outer wall of the piston comprise a first groove structure on the outer wall of the piston, a second groove structure on the outer wall of the piston, a third groove structure on the outer wall of the piston, a fourth groove structure on the outer wall of the piston and a fifth groove structure on the outer wall of the piston, which are sequentially arranged from the cylinder bottom to the cylinder head, wherein the sealing elements in the groove structures on the outer wall of the first piston and the fifth groove structure on the outer wall of the piston are O-shaped sealing rings, the sealing elements in the groove structures on the outer wall of the second piston and the fourth groove structure on the outer wall of the piston are O-shaped retaining rings, and the sealing elements in the groove structures on the outer wall of the third piston are step-combined sealing rings.

Further preferably, the piston rod is further sleeved with a stroke limiting plug, the stroke limiting plug is arranged between the piston and the guide sleeve, and one end of the stroke limiting plug is in contact with the piston; and a part of the stroke limiting plug, which is in contact with the piston rod, is provided with a limiting plug groove structure capable of accommodating the sealing element, and the sealing element in the limiting plug groove structure is an O-shaped ring check ring.

Further preferably, the part of the outer wall of the guide sleeve, which is in contact with the cylinder barrel, is provided with at least one guide sleeve outer wall groove structure capable of accommodating the sealing element, and the inner wall of the guide sleeve is provided with at least one guide sleeve inner wall groove structure capable of accommodating the sealing element.

Further preferably, two groove structures are arranged on the outer wall of the guide sleeve, and the sealing elements in the groove structures on the outer wall of the guide sleeve are O-shaped sealing rings; the guide sleeve inner wall groove structure is set to be 5, and comprises a first guide sleeve inner wall groove structure, a second guide sleeve inner wall groove structure, a third guide sleeve inner wall groove structure, a fourth guide sleeve inner wall groove structure and a fifth guide sleeve inner wall groove structure which are sequentially arranged from the cylinder bottom to the cylinder head, wherein the sealing element in the first guide sleeve inner wall groove structure and the third guide sleeve inner wall groove structure is an O-shaped check ring, the sealing element in the second guide sleeve inner wall groove structure is a stepped combined sealing ring, the sealing element in the fourth guide sleeve inner wall groove structure is a U-shaped sealing element, and the sealing element in the fifth guide sleeve inner wall groove structure is a dustproof ring.

Further preferably, the guide sleeve press-fitting part connecting part and the inner wall of the cylinder barrel can form a cylinder barrel stepped structure for receiving the guide sleeve stepped structure, an internal thread structure is arranged on the guide sleeve press-fitting part connecting part, and the guide sleeve press-fitting part is connected with the cylinder barrel through matching of the external thread structure on the outer wall of the guide sleeve press-fitting part and the internal thread structure.

Further, the invention provides a lifting device, which comprises the hydraulic cylinder in any one of the above technical solutions.

Through the technical scheme, the hydraulic cylinder provided by the first aspect of the invention has the advantages that on one hand, the piston step structure is arranged on the inner wall of the piston, and the piston rod step structure for bearing the piston step structure is formed at the joint of the connecting part of the piston press-mounting part and the piston rod, so that the piston can be abutted between the piston press-mounting part and the connecting part of the piston press-mounting part through the matching between the piston press-mounting part and the connecting part of the piston rod after being sleeved on the piston rod to realize the fixed connection between the piston and the piston rod, the fixed connection method ensures that the piston does not need to rotate in the process of being assembled and connected with the piston rod, therefore, the sealing element arranged in the groove structure on the inner wall of the piston and the piston rod can not relatively rotate, the sealing element arranged between the sealing element and the piston rod can be prevented from being distorted and deformed, and the sealing performance between the piston and the piston rod can be ensured, the occurrence of cavity stringing is greatly avoided; on the other hand, because the outer wall of the guide sleeve is provided with the step structure of the guide sleeve, and the connecting part of the press-fitting part of the guide sleeve arranged on the inner wall of the cylinder barrel at the cylinder head and the inner wall of the cylinder barrel form the step structure of the cylinder barrel for bearing the step structure of the guide sleeve, when the guide sleeve is installed in the cylinder barrel, the guide sleeve can be firstly butted with the step structure of the cylinder barrel to realize the limit, and then the guide sleeve is butted between the press-fitting part of the guide sleeve and the step structure of the cylinder barrel through the matching between the press-fitting part of the guide sleeve and the connecting part of the press-fitting part of the guide sleeve to realize the fixed connection between the guide sleeve and the cylinder barrel, the connecting mode can prevent the guide sleeve from displacing towards one side of the cylinder bottom by the butting between the step structure of the guide sleeve and the step structure of the cylinder barrel, meanwhile, the guide sleeve is butted with the press-fitting part of the guide sleeve to prevent the guide sleeve from displacing towards one side of the rod head of the piston rod, thereby can prevent that the uide bushing from producing axial displacement at the working process of pneumatic cylinder, avoid it to cause structural damage to the cylinder head department of pneumatic cylinder to can play the effect of guaranteeing pneumatic cylinder head department leakproofness, make the pneumatic cylinder have good leakproofness and life.

In the lifting device provided by the second aspect of the present invention, since the lifting device includes the hydraulic cylinder in the above-described aspect, the lifting device also has the advantages of the hydraulic cylinder in the above-described aspect, and since the hydraulic cylinder in the lifting device is not prone to the phenomenon of the cross chamber, the lifting device can have good operation stability and operation safety.

Drawings

FIG. 1 is a schematic perspective view of a hydraulic cylinder according to an embodiment of the present invention.

Description of the reference numerals

1-cylinder 11-guide sleeve press-fitting part connecting part

12-cylinder barrel step structure 2-cylinder head assembly

21-guide sleeve 211-guide sleeve step structure

22-guide sleeve press-fit 3-piston rod assembly

31-piston rod 311-piston press-fitting connection

312-piston rod step structure 32-piston press fitting piece

4-piston assembly 41-piston

411-piston step structure 42-stroke limit plug

5-set screw 6-seal

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

As shown in fig. 1, in an embodiment of a hydraulic cylinder to be provided in the first aspect of the present invention, the hydraulic cylinder includes a cylinder barrel 1, a cylinder head assembly 2, a piston rod assembly 3 and a piston assembly 4, wherein the piston assembly 4 includes a piston 41, a piston step structure 411 is formed on an inner wall of the piston 41, the piston rod assembly 3 includes a piston rod 31 and a piston press-fitting member 32, an end of one end of the piston rod 31 is provided with a piston press-fitting member connecting portion 311, the piston 41 is sleeved on the piston rod 31, and the piston press-fitting member 32 is connected to the piston press-fitting member connecting portion 311 and can abut the piston step structure 411 on the piston rod 31; the cylinder head assembly 2 comprises a guide sleeve 21 and a guide sleeve pressing piece 22, a guide sleeve step structure 211 is formed on the outer wall of the guide sleeve 21, a guide sleeve pressing piece connecting portion 11 is arranged on the inner wall of the cylinder barrel at the cylinder head of the cylinder barrel 1, the guide sleeve 21 is sleeved in the cylinder barrel 1, the guide sleeve pressing piece 22 is connected with the guide sleeve pressing piece connecting portion 11, and the guide sleeve step structure 211 can be abutted to the cylinder head of the cylinder barrel.

Through the technical scheme, in the hydraulic cylinder provided by the first aspect of the invention, on one hand, the piston step structure 411 is arranged on the inner wall of the piston 41, so that after the piston 41 is sleeved on the piston rod 31, the piston 41 can be fixedly connected with the piston rod 31 in an abutting mode through the matching between the piston press-fitting part 32 and the piston press-fitting part connecting part 311, and the piston 41 does not need to rotate in the process of assembling and connecting with the piston rod 31 by the fixed connection method, so that the relative rotation between the sealing element 6 arranged between the inner wall of the piston 41 and the piston rod 31 can be ensured, the relative rotation between the sealing element 6 arranged between the outer wall of the piston 41 and the inner wall of the cylinder barrel 1 can be ensured, the torsional deformation of the sealing element 6 can be avoided, and further the torsional deformation between the piston 41 and the piston rod 31 and between the outer wall of the piston 41 and the inner wall of the cylinder barrel 1 can be ensured The sealing performance greatly avoids the occurrence of cavity crossing phenomenon, and particularly, the sealing element 6 in the groove structure of the inner wall of the piston can be preferably an O-shaped sealing ring; on the other hand, the cylinder step structure 12 for receiving the guide sleeve step structure 211 is preferably designed between the guide sleeve press-fitting part connecting part 11 and the inner wall of the cylinder, because the guide sleeve step structure 211 is arranged on the outer wall of the guide sleeve 21, when the guide sleeve 21 is installed in the cylinder 1, the guide sleeve 21 can be abutted against the cylinder step structure 12 through the guide sleeve step structure 211 to realize the limit, and then the guide sleeve press-fitting part 22 is engaged with the guide sleeve press-fitting part connecting part 11 to be abutted against the guide sleeve press-fitting part 22 and the cylinder step structure 12 to realize the fixed connection between the guide sleeve 21 and the cylinder 1, the connection mode can prevent the guide sleeve 21 from displacing towards the cylinder bottom side through the abutment between the guide sleeve step structure 211 and the cylinder step structure 12, meanwhile, the guide sleeve 21 is also abutted against the guide sleeve press-fitting part 22 to prevent the guide sleeve 21 from displacing towards the rod head side of the piston rod 31, thereby can prevent that uide bushing 21 from producing axial displacement in the course of the work of pneumatic cylinder, avoid it to cause structural damage to the cylinder head department of pneumatic cylinder to can play the effect of guaranteeing pneumatic cylinder head department leakproofness, make the pneumatic cylinder have good leakproofness and life.

Specifically, as shown in fig. 1, in an embodiment of the hydraulic cylinder to be provided by the first aspect of the present invention, the piston press fitting 32 is preferably a compression nut, a piston rod step structure 312 for receiving the piston step structure 411 is formed at a connection portion of the piston press fitting connection portion 311 and the piston rod 31, a threaded connection hole is formed in a middle portion of the compression nut, and a threaded structure is provided on an outer wall of the piston press fitting connection portion 311, so that the compression nut can be screwed with the piston rod through the threaded connection hole and the threaded structure on the piston press fitting connection portion 311, and the adjustment of the distance between the piston press fitting 32 and the piston rod step structure 312 can be conveniently achieved by adopting a screwing manner, so that the compression nut can tightly press fit the piston step structure 411 between the compression nut and the piston rod step structure 312 through rotation adjustment even if there is a manufacturing error between the size of the piston step structure 312 and a design value, therefore, the piston 41 can be prevented from moving along the axial direction of the piston rod 31, and the situation that the sealing element 6 loses the sealing effect due to fatigue aging caused by the relative movement between the sealing element 6 arranged between the piston 41 and the piston rod 31 in the working process of the hydraulic cylinder can be avoided; in order to further prevent the piston 41 and the piston rod 31 from moving relatively, a plurality of set screws 5 are preferably arranged between the compression nut and the piston press-fitting member connecting portion 311, after the compression nut knob is in place to tightly press and fit the piston step structure 411 between the compression nut and the piston rod step structure 312, the set screws 5 are tightened to enable one end of each set screw 5 to abut against the piston press-fitting member connecting portion 311, so that the limit between the piston 41 and the piston press-fitting member connecting portion 311 is formed, and meanwhile, the connecting position between the piston 41 and the piston press-fitting member connecting portion 311 can bear larger torque load, so that the piston 41 and the piston rod 31 are connected more firmly.

Preferably, as shown in fig. 1, in an embodiment of the hydraulic cylinder to be provided by the first aspect of the present invention, a portion of the inner wall of the piston 41, which is in contact with the piston rod 31, is provided with a piston inner wall groove structure capable of accommodating the seal 6, so that the seal 6 can be provided between the inner wall of the piston 41 and the piston rod 31; a plurality of piston outer wall groove structures capable of accommodating the sealing elements 6 are further arranged on the outer wall, which is in contact with the inner wall of the cylinder barrel, of the piston 41, so that the sealing elements 6 can be arranged between the piston 41 and the inner wall of the cylinder barrel, and the cavity crossing phenomenon can be prevented; specifically, the number of the piston outer wall groove structures can be preferably set to 5, and the piston outer wall groove structures comprise a first piston outer wall groove structure, a second piston outer wall groove structure, a third piston outer wall groove structure, a fourth piston outer wall groove structure and a fifth piston outer wall groove structure which are sequentially arranged from the cylinder bottom to the cylinder head, wherein sealing elements 6 in the first piston outer wall groove structure and the fifth piston outer wall groove structure are O-shaped sealing rings, sealing elements 6 in the second piston outer wall groove structure and the fourth piston outer wall groove structure are O-shaped retaining rings, and sealing elements 6 in the third piston outer wall groove structure are step combination sealing rings; the O-shaped sealing ring has good radial load bearing capacity, namely, the O-shaped sealing ring can better bear the pressure between the cylinder barrel 1 and the piston 41, so that the O-shaped sealing ring can be more tightly arranged between the cylinder barrel 1 and the piston 41 to ensure good sealing performance; the O-shaped ring retainer ring has good radial and axial load bearing capacity, and can absorb the load along the moving direction of the piston 41 in the reciprocating movement process of the piston 41, so that a good vibration reduction effect can be achieved, and the movement process of the piston can be smoother; the ladder combination sealing ring can have good high temperature resistance and high pressure resistance, so that the sealing ring still has good sealing performance after long-time sliding friction between the sealing ring and the inner wall of the cylinder barrel, and the sealing reliability is better.

Preferably, as shown in fig. 1, in an embodiment of the hydraulic cylinder to be provided in the first aspect of the present invention, the piston rod 31 is further sleeved with a stroke limiting plug 42, the stroke limiting plug 42 is disposed between the piston 41 and the guide sleeve 21, and one end of the stroke limiting plug 42 is in contact with the piston 41, that is, the stroke limiting plug 42 and the piston 41 are connected to form a whole, and along with the reciprocating movement of the piston 41 in the cylinder, that is, in the working process of the hydraulic cylinder, the stroke limiting plug 42 and the piston rod 31 do not generate relative sliding in a direction opposite to the moving direction of the piston rod 31, so that the resistance in the moving process of the piston rod 31 can be reduced; preferably, the part of the travel limit plug 42, which is in contact with the piston rod 31, is provided with a limit plug groove structure capable of accommodating the sealing element 6, and since the travel limit plug 42 is usually made of a soft material and has a certain flexibility, when the piston 41 moves towards the cylinder head so that the travel limit plug 42 is in contact with the guide sleeve 21, the guide sleeve 21 and the piston 41 generate axial ballast on the travel limit plug 42, and therefore, the sealing element 6 in the limit plug groove structure is preferably an O-ring retainer ring with good axial load bearing capacity.

Preferably, as shown in fig. 1, in an embodiment of the hydraulic cylinder provided by the first aspect of the present invention, a portion of the outer wall of the guide sleeve, which is in contact with the cylinder tube 1, is provided with at least one guide sleeve outer wall groove structure capable of accommodating the sealing member 6, so as to form a seal between the outer wall of the guide sleeve and the cylinder tube 1; the inner wall of the guide sleeve 21 is provided with at least one guide sleeve inner wall groove structure capable of accommodating the sealing member 6, so that sealing can be formed between the piston rod 31 and the guide sleeve 21, and the sealing performance of the whole hydraulic cylinder is guaranteed. Specifically, the number of the guide sleeve outer wall groove structures can be preferably two, and the sealing elements 6 in the two guide sleeve outer wall groove structures are O-shaped sealing rings, so that a double-layer sealing structure is formed, the sealing performance is improved, and the O-shaped sealing rings are simple in structure and convenient to install; the number of the guide sleeve inner wall groove structures can be preferably set to 5, and the guide sleeve inner wall groove structures comprise a first guide sleeve inner wall groove structure, a second guide sleeve inner wall groove structure, a third guide sleeve inner wall groove structure, a fourth guide sleeve inner wall groove structure and a fifth guide sleeve inner wall groove structure which are sequentially arranged from the cylinder bottom to the cylinder head, wherein the sealing elements 6 in the first guide sleeve inner wall groove structure and the third guide sleeve inner wall groove structure can preferably adopt O-shaped ring retaining rings, and because the reciprocating motion of the piston rod 31 can apply a load (namely an axial load) along the motion direction of the piston rod 31 to the sealing elements arranged on the inner wall of the guide sleeve in the working process of the hydraulic cylinder, the O-shaped ring retaining rings with good axial load bearing capacity are required to be adopted, and have good radial load bearing capacity, namely can bear larger pressure applied to the O-shaped ring retaining rings by the piston rod 31 and the inner wall of the guide sleeve, thereby improving the sealing performance between the piston rod 31 and the inner wall of the guide sleeve; the sealing element 6 in the groove structure on the inner wall of the second guide sleeve is a step combined sealing ring which has good high-temperature resistance and high-pressure resistance, so that the sealing element still has good sealing performance after long-time sliding friction between the sealing element and the piston rod 31, and the sealing reliability is better; the sealing element 6 in the groove structure on the inner wall of the fourth guide sleeve is a U-shaped sealing element, and a U-shaped opening of the U-shaped sealing element is arranged towards the bottom of the cylinder barrel 1, so that hydraulic oil can be better prevented from leaking and seeping out from a position between the piston rod 31 and the guide sleeve 21; sealing member 6 in the groove structure of the inner wall of the fifth guide sleeve is a dustproof ring, so that dust particles can be prevented from being attached to the piston rod 31 to cause abrasion to the guide sleeve 21, the piston rod 31 and the sealing member arranged on the inner wall of the guide sleeve, hydraulic oil leakage and seepage are caused, dust particles can be prevented from entering a cavity of the hydraulic cylinder along with the piston rod 31, abrasion is caused to the piston 41, the inner wall of the cylinder barrel and the sealing member 6 between the piston and the inner wall of the cylinder barrel, and the phenomenon of cavity stringing is caused.

More preferably, as shown in fig. 1, in an embodiment of the hydraulic cylinder to be provided by the first aspect of the present invention, the guide sleeve press-fitting connecting portion 11 can be formed with the inner wall of the cylinder barrel to form a cylinder barrel step structure 12 for receiving the guide sleeve step structure 211, and the guide sleeve press-fitting connecting portion 11 is provided with an internal thread structure, the guide sleeve press-fitting 22 is connected to the cylinder barrel 1 by the matching of the external thread structure and the internal thread structure on the outer wall thereof, the adjustment of the distance between the guide sleeve press-fitting 22 and the cylinder barrel step structure 12 can be facilitated by adopting a screwing manner, and the pre-tightening force can be enhanced, so that, even if there is a manufacturing error between the size of the guide sleeve step structure 211 and the design value, the guide sleeve press-fitting 22 can tightly press-fit the guide sleeve step structure 211 between the guide sleeve press-fitting 22 and the cylinder barrel step structure 12 by rotation adjustment, so that the movable guide sleeve 21 can be prevented from moving in the axial direction of the cylinder barrel 1, thereby can avoid in the working process of pneumatic cylinder, locate between sealing member 6 and the cylinder inner wall between uide bushing outer wall and cylinder 1 because often produce relative movement, and make the condition of sealing member 6 fatigue aging loss sealed effect, and cylinder 1 and uide bushing pressure equipment piece 22 adopt foretell structural design and connected mode, can make between uide bushing pressure equipment piece connecting portion 11 and the cylinder 1 replace the form of components of a whole that can function independently design and link together through modes such as welding with integrated into one piece's form, thereby can make the structural strength of cylinder 1's cylinder head department higher, make the cylinder have longer life.

In addition, the invention also provides a lifting device with the hydraulic cylinder, and the lifting device has the advantages of the technical scheme of the hydraulic cylinder, and the hydraulic cylinder in the lifting device is not easy to generate a cavity crossing phenomenon, so that the lifting device has good working stability and working safety.

The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, numerous simple modifications can be made to the technical solution of the invention, including combinations of the individual specific technical features in any suitable way. The invention is not described in detail in order to avoid unnecessary repetition. Such simple modifications and combinations should be considered within the scope of the present disclosure as well.