Hydraulic cylinder and working machine

Abstract

The invention relates to the technical field of hydraulic equipment, and discloses a hydraulic cylinder and an operation machine. The piston rod is inserted into the cylinder barrel, and a first interval space is formed between the piston rod and the cylinder barrel; the sealing assembly comprises a first sealing part arranged in the first interval space; the cylinder barrel is sleeved with the flange, and the flange is fixedly connected with the outer wall of the matching section; the cylinder barrel can be directly matched with the outer wall of the piston rod through the first sealing part, the number of middle parts can be effectively reduced, the outer wall of the piston rod is directly used as a positioning reference, the cylinder head body is arranged on one side of the matching section in a sleeving mode, the piston rod is sleeved with the cylinder head body, and the matching section is in sealing fit with the cylinder head body through a flange. According to the hydraulic cylinder, positioning through a flange is not needed, the coaxiality of the cylinder barrel and the piston rod is remarkably improved, the coaxiality error of the cylinder barrel and the piston rod caused by the large number of middle components and datum planes is reduced, and the situations of shaking and abnormal sound generated in the working process of the hydraulic cylinder are reduced.

Description

Technical Field

[0001] This invention relates to the field of hydraulic equipment technology, specifically to hydraulic cylinders and operating machinery. Background Technology

[0002] Hydraulic systems are critical operating systems in large machinery such as cranes. Hydraulic cylinders are the main working components of hydraulic systems, and their operational status directly affects the normal operation of the machinery. To meet the driving requirements of cranes and other machinery with long boom strokes, long-cylinder single-cylinder pin-type hydraulic cylinders are typically used.

[0003] Currently, in existing hydraulic cylinders, the end of the cylinder barrel is usually connected to the cylinder head via a fixed flange. The inner ring of the flange slides with the internal piston rod through a sealing assembly. Due to its long length, this type of hydraulic cylinder is prone to straightness deviation, resulting in vibration and abnormal noise when subjected to external forces during normal operation of the machinery. This leads to problems of poor working stability and reliability. Summary of the Invention

[0004] In view of this, the present invention provides a hydraulic cylinder and a working machine to solve the problems of poor working stability and poor reliability of existing hydraulic cylinders in terms of assembly form.

[0005] In a first aspect, the present invention provides a hydraulic cylinder, comprising: a cylinder barrel extending along a first direction and having a working space therein, one end of the cylinder barrel forming a mating section; a piston rod extending along the first direction and at least a portion of which is inserted into the working space, the space between the piston rod and the cylinder barrel forming a first gap space; a sealing assembly including a first sealing portion disposed in the first gap space, the inner wall of the mating section sealingly engaging with the outer wall of the piston rod through the first sealing portion; a flange sleeved on the outside of the cylinder barrel, at least a portion of which is fixedly connected to the outer wall of the mating section; and a cylinder head body disposed on one side of the mating section along the first direction, the cylinder head body sleeved on the outside of the piston rod, the mating section sealingly engaging with the cylinder head body through the flange.

[0006] Beneficial effects: By placing the first sealing part in the first gap space, the cylinder can directly cooperate with the outer wall of the piston rod through the first sealing part, which can effectively reduce the number of intermediate parts. The outer wall of the piston rod can be used directly as the positioning reference, eliminating the need for positioning through flanges. This significantly improves the coaxiality of the cylinder and piston rod, greatly reduces the coaxiality error caused by the large number of intermediate parts and reference surfaces, and reduces the vibration and abnormal noise of the hydraulic cylinder during operation. It effectively solves the problems of poor working stability and poor reliability of the existing hydraulic cylinder assembly form.

[0007] In one alternative embodiment, the flange includes a connecting section and an extending section arranged along a first direction. The extending section is connected to the outer wall of the mating section through the connecting section. The extending section is sealed to the cylinder head body. The space between the extending section and the cylinder forms a second gap space. Along the first direction, the length of the connecting section is greater than the length of the extending section.

[0008] Beneficial effects: This type of flange has a longer part that mates with the connecting section and a shorter part that extends beyond the connecting section. This not only makes the connection between the flange and the connecting section more reliable, but also makes it less prone to deformation when the extended section is subjected to forces from the cylinder head and external forces. This makes it less likely for the hydraulic cylinder to have coaxiality errors at the flange position due to deformation or other problems during subsequent operation.

[0009] In one optional embodiment, the flange has a length of L1 along the first direction, with a value ranging from 65mm to 75mm, and the connecting section has a length of L2 along the first direction, with a value ranging from 40mm to 60mm.

[0010] Beneficial effects: While reducing the overall length of the flange, it also increases the length of the connection between the flange and the connecting section. By reducing the flange lever arm, the possibility of flange deformation is reduced, and the connection reliability between the flange and the connecting section is also improved.

[0011] In one alternative embodiment, the sealing assembly further includes a second sealing portion, which is disposed in the second space and connected to the first sealing portion along the first direction, and the second sealing portion is respectively sealed to the protruding section and the piston rod.

[0012] Beneficial effect: The second sealing part can further support the protruding section and improve the reliability of the protruding section's fit.

[0013] In one alternative embodiment, a first assembly end is formed at one end of the cylinder head body near the protruding section. The first assembly end is sleeved on the outside of the protruding section and is sealed to the protruding section. The first assembly end abuts against the second sealing part through the protruding section.

[0014] Beneficial effects: The extended section can directly abut against the second sealing part through the second sealing part, without the need for additional components such as guide sleeves. This reduces the number of hydraulic cylinder components. At the same time, since the cylinder head body also cooperates with the piston rod through the sealing assembly, the coaxiality of the cylinder head body and the piston rod can be further improved.

[0015] In one optional embodiment, the first sealing part includes a first sleeve and a plurality of sealing rings. The first sleeve is sleeved on the outside of the piston rod. The inner ring of the first sleeve is provided with a plurality of sealing grooves at intervals along a first direction. The sealing rings are disposed in the corresponding sealing grooves. The first sleeve abuts against the outer wall of the piston rod through the plurality of sealing rings. The outer ring wall surface of the first sleeve is sealed with the inner ring wall surface of the mating section through the first sealing element.

[0016] Beneficial effects: The arrangement of multiple sealing rings can reduce the load on a single sealing ring, reduce the friction between the sealing ring and the piston rod, improve the sealing reliability and service life of the first sealing part, and the first sealing part has a simple and reliable structure that is easy to process and manufacture.

[0017] In one optional embodiment, the second sealing part includes a second sleeve and a guide ring. The second sleeve is sleeved on the outside of the piston rod and connected to the first sleeve. The inner ring of the second sleeve is provided with a guide groove, and the guide ring is disposed in the corresponding guide groove. The second sleeve abuts against the outer wall of the piston rod through the guide ring. The outer ring wall surface of the second sleeve is sealed with the inner ring wall surface of the protruding section through the second sealing element. The end of the cylinder head away from the extended section forms the second assembly end, and the inner ring wall of the second assembly end abuts against the outer ring wall of the piston rod through a bearing.

[0018] Beneficial effects: The second sealing part has a simple and reliable structure. One end of the cylinder head is supported by a bearing, and the other end can be indirectly supported by a guide ring. This ensures the coaxiality of the cylinder head and the piston rod, while also providing more balanced and reliable support for the cylinder head, avoiding excessive local wear of the bearing due to uneven force.

[0019] In one optional embodiment, the radial thickness of the second sealing part is greater than the radial thickness of the first sealing part, the connecting surface of the outer ring wall of the second sealing part and the outer ring wall of the first sealing part forms a stepped surface, the mating section abuts against the stepped surface, and the mating section abuts against the inner ring wall of the cylinder head body through the second sealing part.

[0020] Beneficial effects: The sealing components can also play a role in axial positioning, which can effectively improve the positional accuracy of the cylinder head and cylinder barrel.

[0021] In one optional embodiment, the length of the first sealing part along the first direction is L3, and the value of L3 ranges from 90mm to 120mm. The sum of the lengths of the first sealing part and the second sealing part along the first direction is L4, and the value of L4 ranges from 140mm to 160mm.

[0022] Beneficial effects: In this type of sealing assembly, the first sealing part is longer and the contact area between the first sealing part and the mating section is also larger, which can effectively improve the coaxiality of adjacent parts at this position. In addition, the second sealing part is shorter, which can also effectively improve the deformation resistance of the second sealing part.

[0023] Secondly, the present invention also provides a working machine, which includes: a machine body and the aforementioned hydraulic cylinder, wherein the hydraulic cylinder is mounted on the machine body. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a top view of a partial location of a hydraulic cylinder according to an embodiment of the present invention; Figure 2 for Figure 1 A cross-sectional view of the sealing assembly of the hydraulic cylinder shown.

[0026] Explanation of reference numerals in the attached figures: 1. Cylinder barrel; 101. Fitting section; 2. Piston rod; 3. Sealing assembly; 301, First sealing part; 3011, First sleeve; 30111, Sealing groove; 3012, Sealing ring; 302, Second sealing part; 3021, Second sleeve; 30212, Guide groove; 3022, Guide ring; 303, Stepped surface; 4. Flange; 401. Connecting section; 402. Extending section; 5. Cylinder head body; 501. First assembly end; 502. Second assembly end; 503. Bearing; X, the first direction. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] The following is combined with Figure 1 and Figure 2The following describes embodiments of the present invention.

[0029] In related technologies, the end of cylinder 1 is typically connected to the cylinder head via a fixed flange 4. The inner ring of flange 4 slides with the internal piston rod 2 via a sealing assembly 3. Both cylinder 1 and piston rod 2 require connection via flange 4 and sealing assembly 3, and then coaxial connection via sealing assembly 3 with piston rod 2. Both cylinder 1 and piston rod 2 are positioned based on flange 4. When flange 4 has a positioning deviation, the coaxiality of both cylinder 1 and piston rod 2 will deviate. Furthermore, this assembly method involves many components and requires numerous assembly and connection points. Due to machining and assembly errors, this type of hydraulic cylinder will result in poor coaxiality between cylinder 1 and piston rod 2, leading to vibration and abnormal noise during operation.

[0030] According to an embodiment of the present invention, a hydraulic cylinder is provided, comprising: a cylinder barrel 1, a piston rod 2, a sealing assembly 3, a flange 4, and a cylinder head 5.

[0031] A cylinder 1 extends along a first direction X and has a working space inside, with one end of the cylinder 1 forming a mating section 101; a piston rod 2 extends along the first direction X and at least a portion of it is inserted into the working space, with the space between the piston rod 2 and the cylinder 1 forming a first gap space; a sealing assembly 3 includes a first sealing part 301 disposed in the first gap space, with the inner wall of the mating section 101 sealingly mating with the outer wall of the piston rod 2 through the first sealing part 301; a flange 4 is fitted onto the outside of the cylinder 1, with at least a portion of the flange 4 fixedly connected to the outer wall of the mating section 101; and a cylinder head 5 is disposed along the first direction X on one side of the mating section 101, with the cylinder head 5 fitted onto the outside of the piston rod 2, and the mating section 101 sealingly mating with the cylinder head 5 through the flange 4.

[0032] In the hydraulic cylinder of this embodiment, the first sealing part 301 is disposed in the first gap space. The cylinder barrel 1 can directly cooperate with the outer wall of the piston rod 2 through the first sealing part 301, which can effectively reduce the number of intermediate parts. The outer wall of the piston rod 2 is directly used as the positioning reference, and there is no need to use the flange 4 for positioning. This significantly improves the coaxiality of the cylinder barrel 1 and the piston rod 2, greatly reduces the coaxiality error caused by the large number of intermediate parts and reference surfaces, and reduces the vibration and abnormal noise of the hydraulic cylinder during operation. It effectively solves the problems of poor working stability and poor reliability of the existing hydraulic cylinder assembly form.

[0033] Wherein, the first direction X refers to Figure 1 The direction of X indicated by the middle arrow.

[0034] Specifically, in related technologies, when operating machinery uses existing hydraulic systems, hydraulic cylinder vibration, swaying, and abnormal noise account for 15% to 20% of all failures, which are relatively common and frequent failure phenomena. However, after using the hydraulic cylinder of this embodiment, the coaxiality between the cylinder barrel 1 and the piston rod 2 is greatly improved. The direct fit between the first sealing part 301 and the inner diameter of the cylinder barrel 1, using the inner circle accuracy of the cylinder barrel 1 as a reference, forces the axis of the first sealing part 301 and the piston rod 2 to be aligned with the axis of the cylinder barrel 1. This structurally eliminates the error transmission of indirect positioning of the flange 4, reducing the proportion of hydraulic cylinder vibration, swaying, and abnormal noise failures to 1% or less, and significantly improving the failure situation of long hydraulic cylinders.

[0035] In one possible implementation, the flange 4 includes a connecting section 401 and an extending section 402 arranged along the first direction X. The extending section 402 is connected to the outer wall of the mating section 101 through the connecting section 401. The extending section 402 is sealed to the cylinder head body 5. The space between the extending section 402 and the cylinder barrel 1 forms a second gap space. Along the first direction X, the length of the connecting section 401 is greater than the length of the extending section 402. In this form of flange 4, the part that mates with the connecting section 401 is longer, while the part that extends out of the connecting section 401 is shorter. This not only makes the connection between the flange 4 and the connecting section 401 more reliable, but also makes it less likely for the extending section 402 to deform when subjected to forces from the cylinder head body 5 and external forces. This makes it less likely for the hydraulic cylinder to have coaxiality errors at the flange 4 position due to deformation or other problems during subsequent operation.

[0036] Specifically, there is no limitation on the length of the connecting section 401 and the extending section 402. Since the size of the hydraulic cylinder is diverse, it can be flexibly selected according to actual needs.

[0037] In one possible implementation, the length of flange 4 along the first direction X is L1, with L1 ranging from 65mm to 75mm, and the length of connecting section 401 along the first direction X is L2, with L2 ranging from 40mm to 60mm. While reducing the overall length of flange 4, the length of the connection position between flange 4 and connecting section 401 is increased. This can improve the rigidity of flange 4 itself, reduce the possibility of flange 4 deformation by reducing the lever arm of flange 4, and improve the connection reliability between flange 4 and connecting section 401.

[0038] In related technologies, the overall length of flange 4 can reach 250mm. Since the inner ring of flange 4 slides with the internal piston rod 2 through sealing assembly 3, the protruding part of flange 4 is generally long in order to facilitate the installation of sealing assembly 3, while the connection part between flange 4 and cylinder 1 is short. Due to the long length of hydraulic cylinder, when hydraulic cylinder is under force, the position of flange 4 is prone to act as a fulcrum and bear a large stress. Flange 4 is not only prone to deformation itself, but also prone to deformation at the connection position due to the relatively weak connection part between flange 4 and cylinder 1, which in turn affects the coaxiality between the mating parts.

[0039] Using the hydraulic cylinder of this embodiment, while changing the structure and position of the sealing component 3, the overall length of the hydraulic cylinder can also be shortened by shortening the length of the flange 4. This can improve the coaxiality between the internal components of the hydraulic cylinder and reduce the machining difficulty of the hydraulic cylinder.

[0040] Optionally, the value of L1 can be any one of 65mm, 67mm, 69mm, 70mm, 71mm, 73mm, and 75mm, or a value between any two of these values.

[0041] Optionally, the value of L2 can be any one of 40mm, 45mm, 50mm, 55mm, 60mm or any value between two of them.

[0042] Preferably, L1 is 70mm and L2 is 50mm.

[0043] In one possible implementation, the sealing assembly 3 further includes a second sealing part 302. Along the first direction X, the second sealing part 302 is disposed in the second gap space and connected to the first sealing part 301. The second sealing part 302 is in sealing cooperation with the extension section 402 and the piston rod 2 respectively. The second sealing part 302 can further support the extension section 402 and improve the cooperation reliability of the extension section 402.

[0044] In one possible implementation, a first mounting end 501 is formed at one end of the cylinder head 5 near the extension section 402. The first mounting end 501 is sleeved on the outside of the extension section 402 and is sealed to the extension section 402. The first mounting end 501 abuts against the second sealing part 302 through the extension section 402. The extension section 402 can directly abut against the second sealing part 302 through the second sealing part 302 without the need for additional components such as guide sleeves. This reduces the number of hydraulic cylinder components. Since the cylinder head 5 also cooperates with the piston rod 2 through the sealing assembly 3, the coaxiality between the cylinder head 5 and the piston rod 2 can be further improved.

[0045] In related technologies, when the cylinder head 5 and the cylinder barrel 1 simultaneously press against the same position of the sealing assembly 3 radially, the friction between the sealing assembly 3 and the piston rod 2 is easily increased, which affects the normal operation of the hydraulic cylinder. Therefore, the flange 4 is usually long, and an independent guide sleeve is usually set on one side of the sealing assembly 3 axially. The guide sleeve supports the part of the cylinder head 5 that presses against the flange 4. There are many hydraulic cylinder components of this type, and the independent guide sleeve is also prone to coaxiality error accumulation.

[0046] Using the hydraulic cylinder of this embodiment, the functions of the original sealing component 3 and guide sleeve can be achieved with a single sealing component 3, reducing the number of parts, reducing the difficulty of part processing, and reducing assembly steps. In addition, the sealing component 3 itself occupies less space, which allows the flange 4 to reduce its length.

[0047] In one possible implementation, the first sealing part 301 includes a first sleeve 3011 and a plurality of sealing rings 3012. The first sleeve 3011 is sleeved on the outside of the piston rod 2. The inner ring of the first sleeve 3011 is provided with a plurality of sealing grooves 30111 at intervals along the first direction X. The sealing rings 3012 are disposed in the corresponding sealing grooves 30111. The first sleeve 3011 abuts against the outer wall of the piston rod 2 through the plurality of sealing rings 3012. The outer ring wall surface of the first sleeve 3011 is sealed with the inner ring wall surface of the mating section 101 through the first sealing element. The arrangement of the plurality of sealing rings 3012 can reduce the load borne by a single sealing ring 3012, reduce the friction between the sealing ring 3012 and the piston rod 2, and improve the sealing reliability and service life of the first sealing part 301. The first sealing part 301 has a simple and reliable structure and is easy to process and manufacture.

[0048] The specific number of sealing grooves 30111 and sealing rings 3012 is not limited; there can be two or more, and the number can be flexibly selected according to the requirements.

[0049] Preferably, such as Figure 2 As shown, there are two sealing grooves 30111 and two sealing rings 3012.

[0050] In one possible embodiment, the second sealing part 302 includes a second sleeve 3021 and a guide ring 3022. The second sleeve 3021 is sleeved on the outside of the piston rod 2 and connected to the first sleeve 3011. The inner ring of the second sleeve 3021 is provided with a guide groove 30212, and the guide ring 3022 is disposed in the corresponding guide groove 30212. The second sleeve 3021 abuts against the outer wall of the piston rod 2 through the guide ring 3022. The outer ring wall surface of the second sleeve 3021 is connected to the inner ring wall surface of the protruding section 402 through the second sealing element. Sealing fit; the end of the cylinder head 5 away from the protruding section 402 forms the second assembly end 502. The inner ring wall of the second assembly end 502 abuts against the outer ring wall of the piston rod 2 through the bearing 503. The second sealing part 302 has a simple and reliable structure. One end of the cylinder head 5 is supported by the bearing 503, and the other end can be indirectly supported by the guide ring 3022. While ensuring the coaxiality of the cylinder head 5 and the piston rod 2, it can also support the cylinder head 5 in a more balanced and reliable manner, avoiding excessive local wear of the bearing 503 due to uneven force.

[0051] Among these improvements, shortening flange 4 and eliminating the independent guide sleeve reduce intermediate positioning steps, lowering the impact of accumulated errors from multiple components on concentricity. Meanwhile, as... Figure 1 As shown, this structure can also shorten the distance between the guide belt and the sealing ring 3012, enhance the immediacy of radial constraint, and reduce axial offset during operation.

[0052] Specifically, such as Figure 1 As shown, the guide ring 3022 is preferably made of C480 steel, and the bearing 503 is made of copper-based oil-impregnated alloy. Oil-free lubrication is achieved through its own grease, reducing frictional resistance during the reciprocating motion of the piston rod 2. Simultaneously, the guide ring 3022 assists in bearing radial force, further suppressing off-center loading. The seals have better support, improving the service life of the hydraulic cylinder.

[0053] The guide ring 3022 and the bearing 503 can also be made of other existing alloys, as long as the above-mentioned effects can be achieved.

[0054] Furthermore, such as Figure 1 As shown, the inner ring wall of the cylinder head body 5 near the first assembly end 501 is also provided with an assembly groove, and a flexible support ring is provided in the assembly groove to further support the cylinder head body 5.

[0055] In addition, the second sealing part 302 has a guide ring 3022, which can effectively improve the uniformity of the force on the sealing assembly 3 as a whole, prevent the second sealing part 302 from deforming under pressure, and prevent excessive pressure in some parts of the first sealing part 301, thus avoiding unilateral wear of some of the sealing rings 3012.

[0056] In one possible implementation, the radial thickness of the second sealing part 302 is greater than the radial thickness of the first sealing part 301. The connecting surface between the outer ring wall of the second sealing part 302 and the outer ring wall of the first sealing part 301 forms a stepped surface 303. The mating section 101 abuts against the stepped surface 303. The mating section 101 abuts against the inner ring wall of the cylinder head body 5 through the second sealing part 302. The sealing assembly 3 can also play an axial positioning role, which can effectively improve the positional accuracy of the cylinder head body 5 and the cylinder barrel 1.

[0057] In one possible implementation, the length of the first sealing part 301 along the first direction X is L3, and the value of L3 ranges from 90mm to 120mm. The sum of the lengths of the first sealing part 301 and the second sealing part 302 along the first direction X is L4, and the value of L4 ranges from 140mm to 160mm. In this type of sealing assembly 3, the length of the first sealing part 301 is relatively long, and the contact area between the first sealing part 301 and the mating section 101 is also relatively large, which can effectively improve the coaxiality of adjacent components at this position. In addition, the length of the second sealing part 302 is relatively short, which can also effectively improve the deformation resistance of the second sealing part 302.

[0058] Optionally, the value of L3 can be any one of 90mm, 95mm, 100mm, 105mm, 110mm, 115mm, 120mm or a value between any two of these values.

[0059] Optionally, the value of L4 can be any one of 140mm, 145mm, 150mm, 155mm, 160mm, or a value between any two of them.

[0060] Preferably, L3 is 100mm and L4 is 152mm.

[0061] According to an embodiment of the present invention, in another aspect, a working machine is provided, comprising: a machine body and the aforementioned hydraulic cylinder, the hydraulic cylinder being mounted on the machine body.

[0062] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope defined by the appended claims.

Claims

1. A hydraulic cylinder characterized by, The application relates to a cylinder-piston unit, which comprises: a cylinder (1) extending along a first direction (X) and having a working space inside, one end of the cylinder (1) forming a fitting section (101); a piston rod (2) extending along the first direction (X) and at least partially arranged in the working space, a space between the piston rod (2) and the cylinder (1) forming a first interval space; a sealing assembly (3) comprising a first sealing part (301) arranged in the first interval space, an inner wall of the fitting section (101) being sealed and matched with an outer wall of the piston rod (2) through the first sealing part (301); a flange (4) sleeved on the outside of the cylinder (1), at least a part of the flange (4) being fixedly connected with an outer wall of the fitting section (101); a cylinder head body (5) arranged on one side of the fitting section (101) along the first direction (X), the cylinder head body (5) being sleeved on the outside of the piston rod (2), the fitting section (101) being sealed and matched with the cylinder head body (5) through the flange (4).

2. The hydraulic cylinder of claim 1, wherein, The flange (4) comprises a connecting section (401) and an extending section (402) arranged along the first direction (X), the extending section (402) being connected with the outer wall of the fitting section (101) through the connecting section (401), the extending section (402) being sealed and matched with the cylinder head body (5), a space between the extending section (402) and the cylinder (1) forming a second interval space, the length of the connecting section (401) being greater than the length of the extending section (402) along the first direction (X).

3. The hydraulic cylinder of claim 2, wherein, The length of the flange (4) along the first direction (X) is L1, the value range of L1 being 65mm to 75mm, the length of the connecting section (401) along the first direction (X) is L2, the value range of L2 being 40mm to 60mm.

4. The hydraulic cylinder of claim 2, wherein, The sealing assembly (3) further comprises a second sealing part (302), the second sealing part (302) being arranged in the second interval space and connected with the first sealing part (301) along the first direction (X), the second sealing part (302) being sealed and matched with the extending section (402) and the piston rod (2) respectively.

5. The hydraulic cylinder of claim 4, wherein, One end of the cylinder head body (5) close to the extending section (402) forms a first assembly end (501), the first assembly end (501) being sleeved on the outside of the extending section (402), the first assembly end (501) being sealed and matched with the extending section (402), the first assembly end (501) being abuttingly matched with the second sealing part (302) through the extending section (402).

6. The hydraulic cylinder of claim 5, wherein, The first sealing part (301) comprises a first sleeve (3011) and a plurality of sealing rings (3012), the first sleeve (3011) is sleeved on the outside of the piston rod (2), and a plurality of sealing grooves (30111) are arranged at the inner ring of the first sleeve (3011) and spaced apart along the first direction (X), the sealing ring (3012) is arranged in the corresponding sealing groove (30111), the first sleeve (3011) is in abutting fit with the outer wall of the piston rod (2) through the plurality of sealing rings (3012), and the outer ring wall surface of the first sleeve (3011) is in sealing fit with the inner ring wall surface of the fitting section (101) through a first sealing element.

7. The hydraulic cylinder of claim 6, wherein, The second sealing part (302) comprises a second sleeve (3021) and a guide ring (3022), the second sleeve (3021) is sleeved on the outside of the piston rod (2) and connected with the first sleeve (3011), the inner ring of the second sleeve (3021) is provided with a guide groove (30212), the guide ring (3022) is arranged in the corresponding guide groove (30212), the second sleeve (3021) is in abutting fit with the outer wall of the piston rod (2) through the guide ring (3022), and the outer ring wall surface of the second sleeve (3021) is in sealing fit with the inner ring wall surface of the extending section (402) through a second sealing element. The second assembly end (502) of the cylinder head body (5) is formed at one end away from the extending section (402), and the inner ring wall surface of the second assembly end (502) is in abutting fit with the outer ring wall surface of the piston rod (2) through a bearing (503).

8. The hydraulic cylinder of any one of claims 4 to 6, wherein, The radial thickness of the second sealing part (302) is greater than the radial thickness of the first sealing part (301), a connecting surface of the outer ring wall of the second sealing part (302) and the outer ring wall surface of the first sealing part (301) forms a stepped surface (303), the fitting section (101) is in abutting fit with the stepped surface (303), and the fitting section (101) is in abutting fit with the inner ring wall surface of the cylinder head body (5) through the second sealing part (302).

9. The hydraulic cylinder of any one of claims 4 to 6, wherein, The length of the first sealing part (301) along the first direction (X) is L3, the value range of L3 is 90mm to 120mm, and the sum of the lengths of the first sealing part (301) and the second sealing part (302) along the first direction (X) is L4, and the value range of L4 is 140mm to 160mm.

10. A work machine characterized by, Comprise: A machine body and the hydraulic cylinder in any one of claims 1 to 9, the hydraulic cylinder is assembled on the machine body. Comprise:

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