Piston rod sealing assembly

Abstract

The piston rod sealing assembly comprises a first cylinder barrel, a piston rod, a first sealing piece and a cover plate, a first through hole and a first groove are formed in the first cylinder barrel, the piston rod is movably arranged in the first through hole in a penetrating mode, the first sealing piece is located in the first groove, and the first sealing piece is in interference fit with the piston rod and the first groove; the cover plate comprises a body and a protruding part, the body is connected with the first end of the first cylinder barrel, a second groove is formed in the side, facing the first groove, of the protruding part, and the sectional area of at least part of the second groove is smaller than that of the first groove. And when the piston rod moves towards one side of the second groove, at least part of the first sealing piece enters the second groove from the first groove, so that the contact pressure between the first sealing piece and the piston rod is increased. When the piston rod moves outwards, the contact pressure between the first sealing piece and the piston rod can be increased, and therefore the risk of oil leakage is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of high-pressure oil cylinder sealing, and particularly relates to a piston rod sealing assembly. BACKGROUND

[0002] The high-pressure oil cylinder realizes energy conversion based on Pascal's law and is widely applied to heavy machinery, industrial automation and the like. The high-pressure oil cylinder needs to be sealed by a sealing assembly during use to prevent too much oil from being taken out when the piston rod moves.

[0003] In the related art, the sealing assembly of the high-pressure oil cylinder generally comprises a sealing ring, the sealing ring is installed in a sealing groove in the cylinder barrel, and the sealing ring is tightly sleeved on the surface of the piston rod. When the piston rod moves in the cylinder barrel, the sealing ring can prevent the oil on the surface of the piston rod from leaking outward.

[0004] However, in the related art, the contact pressure between the sealing ring and the piston rod cannot meet the sealing requirement, and in particular, the contact pressure between the sealing ring and the piston rod decreases after long-time use, and there is a risk of oil leakage. SUMMARY

[0005] In order to overcome the above-mentioned defects in the related art, the application aims to provide a piston rod sealing assembly, which can improve the contact pressure between the first sealing member and the piston rod when the piston rod moves outward, thereby reducing the risk of oil leakage.

[0006] The application provides a piston rod sealing assembly, which comprises:

[0007] A first cylinder barrel, a first through hole and a first groove are arranged in the first cylinder barrel, the first through hole penetrates through the first cylinder barrel, the first groove is located at a first end of the first cylinder barrel and is located on the outer periphery side of the first through hole;

[0008] A piston rod, the piston rod is movably arranged in the first through hole;

[0009] A first sealing member, the first sealing member is located in the first groove, and the first sealing member is in interference fit with the piston rod and the first groove;

[0010] A cover plate, the cover plate comprises a body and a protruding portion, the body is connected with the first end of the first cylinder barrel, the protruding portion corresponds to the first groove and protrudes towards the side away from the first groove, a second through hole is arranged in the protruding portion, and the piston rod is movably arranged in the second through hole; a second groove is formed on the side of the protruding portion facing the first groove, and the cross-sectional area of at least part of the second groove is smaller than that of the first groove;

[0011] When the piston rod moves towards the side of the second groove, at least part of the first seal enters the second groove from the first groove, so that the contact pressure between the first seal and the piston rod increases.

[0012] In a possible implementation, the cross-sectional area of the second groove gradually decreases in the direction away from the first groove.

[0013] In a possible implementation, the protruding portion is provided with a plurality of truncated grooves extending from the second through hole to the body, and the plurality of truncated grooves are arranged at intervals along the circumferential direction of the protruding portion.

[0014] In a possible implementation, the body and the protruding portion are integrally formed, and the thickness of the protruding portion is less than the thickness of the body.

[0015] In a possible implementation, the body is provided with a plurality of first fixing holes, the first end of the first cylinder is provided with a plurality of second fixing holes, the plurality of first fixing holes correspond to the plurality of second fixing holes one by one, and a fastener is connected to the second fixing hole after passing through the first fixing hole.

[0016] In a possible implementation, a sealing gasket is further arranged between the body and the first end of the first cylinder.

[0017] In a possible implementation, the first groove is arranged around the first through hole, the first seal is a sealing ring, and the cross section of the sealing ring is circular, square or elliptical.

[0018] In a possible implementation, the method further comprises:

[0019] The second cylinder is provided with a third through hole and a third groove, the third through hole penetrates through the second cylinder, the piston rod is movably arranged in the third through hole, and the third groove is located at the first end of the second cylinder and on the outer circumferential side of the third through hole.

[0020] The second seal is located between the second end of the first cylinder and the first end of the second cylinder, and at least part of the second seal is located in the third groove, and the second seal is in interference fit with the piston rod.

[0021] When the piston rod moves towards the side of the second groove, the contact pressure between the second seal and the piston rod increases.

[0022] In a possible implementation, the included angle between the first end of the second seal and the piston rod is less than the included angle between the second end of the second seal and the piston rod.

[0023] In a possible implementation, the second sealing member comprises a metal framework and a rubber layer wrapped outside the metal framework, and the metal framework is bent towards the third groove.

[0024] The application provides a piston rod sealing assembly, which comprises a first cylinder, a piston rod, a first sealing member and a cover plate. The first cylinder is provided with a first through hole and a first groove. The first through hole penetrates the first cylinder, and the first groove is located at the first end of the first cylinder and on the outer circumferential side of the first through hole. The piston rod is movably arranged in the first through hole. The first sealing member is arranged in the first groove and is in interference fit with the piston rod and the first groove. The cover plate comprises a body and a protruding portion. The body is connected to the first end of the first cylinder, and the protruding portion corresponds to the first groove and protrudes towards the side away from the first groove. The protruding portion is provided with a second through hole, and the piston rod is movably arranged in the second through hole. The side of the protruding portion facing the first groove is provided with a second groove. The cross-sectional area of at least part of the second groove is smaller than that of the first groove. When the piston rod moves towards the side of the second groove (i.e. outward), at least part of the first sealing member enters the second groove, so that the contact pressure between the first sealing member and the piston rod increases. The application sets the second groove corresponding to the first groove, and the cross-sectional area of at least part of the second groove is smaller than that of the first groove. When the piston rod moves towards the side of the second groove (i.e. outward), the first sealing member is driven to enter the second groove. Since the cross-sectional area of the second groove is smaller than that of the first groove, the deformation of the first sealing member in the second groove increases, thereby increasing the contact pressure between the first sealing member and the piston rod, reducing the amount of oil carried out by the piston rod when moving outward, and reducing the risk of oil leakage. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the application or the related art, the following will briefly introduce the drawings needed to be used in the embodiments or the related art description. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0026] Figure 1 A structural diagram of a piston rod sealing assembly provided by an embodiment of the application;

[0027] Figure 2 A top view of a piston rod sealing assembly provided by an embodiment of the application;

[0028] Figure 3 A sectional view of a piston rod sealing assembly provided by an embodiment of the application.

[0029] Reference signs:

[0030] 100 - first cylinder; 110 - first through hole; 120 - first groove;

[0031] 200 - piston rod;

[0032] 300 - first sealing member;

[0033] 400 - cover plate; 410 - body; 411 - first fixing hole; 420 - protruding part; 421 - second through hole; 422 - second groove; 423 - truncated groove;

[0034] 500 - sealing gasket;

[0035] 600 - second cylinder; 610 - third through hole; 620 - third groove;

[0036] 700 - second sealing member; 710 - metal framework; 720 - rubber layer. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some of the embodiments of the present application, but not all the embodiments of the present application.

[0038] Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. The embodiments and features in the embodiments below can be combined with each other without conflict.

[0039] As described in the background, in the related art, the contact pressure between the sealing ring and the piston rod in the sealing assembly of the high-pressure oil cylinder is small, and there is a risk of oil leakage.

[0040] Therefore, the embodiments of the present application aim to provide a piston rod sealing assembly. By setting a second groove corresponding to the first groove, and the cross-sectional area of at least part of the second groove being smaller than the cross-sectional area of the first groove, when the piston rod moves towards the side of the second groove (i.e. outward), the first sealing member can be driven into the second groove. Since the cross-sectional area of the second groove is smaller than the cross-sectional area of the first groove, the deformation amount of the first sealing member in the second groove increases, thereby increasing the contact pressure between the first sealing member and the piston rod, reducing the amount of oil carried out by the piston rod when moving outward, and thereby reducing the risk of oil leakage.

[0041] The content of the embodiments of the present application will be described in detail below with reference to the drawings, so that those of ordinary skill in the art can understand the content of the present application in more detail.

[0042] Please refer to Figures 1-3The embodiment provides a piston rod sealing assembly, which comprises:

[0043] A first cylinder barrel 100 is provided with a first through hole 110 and a first groove 120. The first through hole 110 penetrates the first cylinder barrel 100. The first groove 120 is located at the first end (the upper end of the first cylinder barrel 100) of the first cylinder barrel 100 and is located at the outer circumferential side of the first through hole 110. Exemplarily, one side of the first groove 120 is in communication with the first through hole 110. The first groove 120 can be provided in plurality. The plurality of first grooves 120 are arranged at intervals in the circumferential direction of the first through hole 110. Alternatively, the first groove 120 can be arranged around the first through hole 110. Figure 3 A piston rod 200 is movably arranged in the first through hole 110. The piston rod 200 can be driven by high-pressure oil to move along the first through hole 110.

[0044] A first sealing member 300 is arranged in the first groove 120. The first sealing member 300 is in interference fit with the piston rod 200 and the first groove 120.

[0045] A cover plate 400 is arranged on the first end of the first cylinder barrel 100. The cover plate 400 comprises a body 410 and a protruding portion 420. The body 410 is connected to the first end of the first cylinder barrel 100. Exemplarily, the body 410 can be connected to the first cylinder barrel 100 by means of a fastener such as a bolt. The protruding portion 420 corresponds to the first groove 120 and protrudes towards the side away from the first groove 120. The protruding portion 420 is provided with a second through hole 421 corresponding to the first through hole 110. The piston rod 200 is movably arranged in the second through hole 421. The protruding portion 420 is formed with a second groove 422 on the side facing the first groove 120. At least part of the second groove 422 has a cross-sectional area smaller than that of the first groove 120. That is, in the plane perpendicular to the axial direction of the piston rod 200, there is part of the second groove 422 having a cross-sectional area smaller than that of the first groove 120.

[0046]

[0047] ​When the piston rod 200 moves towards the second groove 422 (i.e. outward), at least part of the first seal 300 enters the second groove 422 from the first groove 120, so that the contact pressure between the first seal 300 and the piston rod 200 increases, thereby preventing the oil on the surface of the piston rod 200 from leaking outward. When the piston rod 200 moves towards the second groove 422 (i.e. inward), the first seal 300 reenters the first groove 120 from the second groove 422, and the contact pressure between the first seal 300 and the piston rod 200 returns to normal, thereby accelerating the inward return of the oil on the surface of the piston rod 200. It can be understood that, by using the scheme of the embodiment, the contact pressure between the first seal 300 and the piston rod 200 when the piston rod 200 moves outward is greater than the contact pressure between the first seal 300 and the piston rod 200 when the piston rod 200 moves inward, so that the leakage amount when the piston rod 200 moves outward is reduced, the oil return amount when the piston rod 200 moves inward remains unchanged, that is, the pump return rate when the piston rod 200 moves inward is greater than the leakage rate when the piston rod 200 moves outward, thereby achieving the purpose of reducing the overall oil leakage.

[0048] By setting the second groove 422 corresponding to the first groove 120, and at least part of the second groove 422 having a smaller cross-sectional area than the first groove 120, when the piston rod 200 moves towards the second groove 422 (i.e. outward), the first seal 300 can be driven to enter the second groove 422. Since the cross-sectional area of the second groove 422 is smaller than that of the first groove 120, the deformation amount of the first seal 300 in the second groove 422 increases, thereby increasing the contact pressure between the first seal 300 and the piston rod 200, reducing the amount of oil carried out by the piston rod 200 when moving outward, and thereby reducing the risk of oil leakage.

[0049] Please continue to refer to Figure 3 In the embodiment, the cross-sectional area of the second groove 422 gradually decreases in the direction away from the first groove 120.

[0050] Exemplarily, the cross section of the protruding portion 420 can be in the shape of a circular arc, and the gap between the protruding portion 420 and the piston rod 200 gradually decreases in the direction away from the first groove 120. The protruding portion 420 in the shape of a circular arc can better adapt to the shape of the first seal 300, thereby facilitating the first seal 300 to enter the inside of the second groove 422 under the driving of the piston rod 200.

[0051] In other possible embodiments, the cross section of the protruding portion 420 can also be in the shape of an inclined line, and the gap between the protruding portion 420 and the piston rod 200 gradually decreases in the direction away from the first groove 120.

[0052] Please continue to refer to Figure 2The protruding portion 420 of the embodiment can be made of an elastic material, for example, an elastic metal sheet. The protruding portion 420 is provided with a plurality of cut-off grooves 423 extending from the second through hole 421 to the body 410, and the plurality of cut-off grooves 423 are arranged at intervals in the circumferential direction of the protruding portion 420.

[0053] In the embodiment, the protruding portion 420 is provided as an elastic metal sheet, so that the protruding portion 420 can be deformed to a certain extent under the action of the first seal 300, so as to increase the size of the second groove 422, thereby increasing the deformation amount of the first seal 300, further increasing the contact pressure between the first seal 300 and the piston rod 200, reducing the amount of oil brought out by the piston rod 200 when moving outward, and thereby reducing the risk of oil leakage. By arranging a plurality of cut-off grooves 423 in the circumferential direction of the protruding portion 420, the difficulty of deforming the protruding portion 420 can be reduced.

[0054] In the embodiment, the body 410 and the protruding portion 420 can be integrally formed, and the thickness of the protruding portion 420 is less than the thickness of the body 410.

[0055] Exemplarily, the body 410 and the protruding portion 420 can be integrally formed by welding, or the body 410 and the protruding portion 420 can be integrally formed by casting, thereby improving the production efficiency of the cover plate 400. The body 410 is provided with a relatively large thickness, so as to ensure the strength of the body 410, thereby ensuring the connection strength between the cover plate 400 and the first cylinder 100. The protruding portion 420 is provided with a relatively small thickness, so as to ensure that the protruding portion 420 has a certain deformation capacity, thereby increasing the size of the second groove 422.

[0056] Please continue to refer to Figure 2 The body 410 of the embodiment is provided with a plurality of first fixing holes 411, and the first end of the corresponding first cylinder 100 is provided with a plurality of second fixing holes (not shown in the figure). The plurality of first fixing holes 411 correspond one-to-one to the plurality of second fixing holes, and a fastener is connected to the second fixing hole after passing through the first fixing hole 411.

[0057] Exemplarily, the first fixing hole 411 of the embodiment can be a through hole, the second fixing hole can be a threaded hole, and the fastener can be a bolt. The bolt is locked to the corresponding threaded hole after passing through the through hole, so as to fixedly connect the body 410 and the first cylinder 100.

[0058] Please continue to refer to Figure 1 and Figure 3 The body 410 of the embodiment is further provided with a sealing gasket 500 between the body 410 and the first end of the first cylinder 100.

[0059] For example, the sealing gasket 500 can be a rubber gasket, and the sealing gasket 500 is fixed between the body 410 and the first cylinder 100 by the locking force when the body 410 is connected to the first cylinder 100. By providing the sealing gasket 500, the probability of oil in the first groove 120 leaking outward through the gap between the body 410 and the first cylinder 100 can be reduced.

[0060] In this embodiment, the first groove 120 may be arranged around the first through hole 110, thereby increasing the contact area between the first seal 300 and the piston rod 200. The first seal 300 may be a sealing ring, and the cross-section of the sealing ring may be selected as circular, square or elliptical as needed.

[0061] Please continue to refer to Figure 1 and Figure 3 The piston rod sealing assembly in this embodiment further includes:

[0062] The second cylinder 600 has a third through hole 610 and a third groove 620 inside. The third through hole 610 penetrates the second cylinder 600 and corresponds to the first through hole 110. The piston rod 200 is movably inserted through the third through hole 610. The third groove 620 is located at the first end of the second cylinder 600. Figure 3 The third groove 620 is located at the upper end of the second cylinder 600 shown, and is situated on the outer periphery of the third through hole 610. Exemplarily, one side of the third groove 620 is connected to the third through hole 610. Multiple third grooves 620 may be provided, spaced apart circumferentially along the third through hole 610; alternatively, the third grooves 620 may surround the third through hole 610.

[0063] The second seal 700 is located at the second end of the first cylinder 100. Figure 3 The second seal 700 is located between the lower end of the first cylinder 100 and the first end of the second cylinder 600 to seal the gap between the first cylinder 100 and the second cylinder 600. At least a portion of the second seal 700 is located within the third groove 620, and the second seal 700 is interference-fitted with the piston rod 200.

[0064] When the piston rod 200 moves towards the second groove 422 (i.e. outward), the piston rod 200 drives the second sealing member 700 to move towards the side away from the third groove 620, so that the deformation amount of the second sealing member 700 increases, the contact pressure between the second sealing member 700 and the piston rod 200 increases, thereby preventing the oil on the surface of the piston rod 200 from leaking outward. When the piston rod 200 moves towards the second groove 422 (i.e. inward), the piston rod 200 drives the second sealing member 700 to move towards the third groove 620, so that the deformation amount of the second sealing member 700 returns to normal, the contact pressure between the second sealing member 700 and the piston rod 200 returns to normal, thereby accelerating the inward flow of the oil on the surface of the piston rod 200.

[0065] It can be understood that, by arranging the second sealing member 700 in series with the first sealing member 300, when the piston rod 200 moves outward, the contact pressure between the first sealing member 300 and the piston rod 200 and the contact pressure between the second sealing member 700 and the piston rod 200 both increase, thereby reducing the risk of oil leakage; when the piston rod 200 moves inward, the contact pressure between the first sealing member 300 and the piston rod 200 and the contact pressure between the second sealing member 700 and the piston rod 200 both return to normal, thereby accelerating the inward flow of the oil on the surface of the piston rod 200. That is, the inward movement of the piston rod 200 in the embodiment has a larger pump return rate than the outward movement of the piston rod 200, thereby achieving the purpose of reducing the overall oil leakage.

[0066] Please continue to refer to Figure 3 In the embodiment, the included angle between the first end (i.e. the upper end of the second sealing member 700 as shown in the drawings) of the second sealing member 700 and the piston rod 200 is smaller than the included angle between the second end (i.e. the lower end of the second sealing member 700 as shown in the drawings) of the second sealing member 700 and the piston rod 200. Figure 3 Figure 3

[0067] Exemplarily, as shown in the drawings, the included angle between the first end of the second sealing member 700 and the piston rod 200 is an acute angle, and the included angle between the second end of the second sealing member 700 and the piston rod 200 is close to a right angle, so that the contact pressure between the first end of the second sealing member 700 and the piston rod 200 is larger, and the contact pressure between the second end of the second sealing member 700 and the piston rod 200 is smaller, thereby making the oil on the surface of the piston rod 200 more easily flow inward. Figure 3 Please continue to refer to

[0068] The second sealing member 700 of the embodiment includes a metal framework 710 and a rubber layer 720 wrapped outside the metal framework 710, and the metal framework 710 is bent towards the third groove 620. Figure 3

[0069] ​​​Exemplarily, the second seal 700 of the embodiment is arranged around the piston rod 200, the metal framework 710 can be a spring, and the rubber layer 720 can be coated on the outer side of the metal framework 710 by using an injection molding process. The metal framework 710 is bent from the gap between the first cylinder barrel 100 and the second cylinder barrel 600 into the third groove 620, so that the metal framework 710 has a certain pre-tightening force, so as to abut the rubber layer 720 to the surface of the piston rod 200, so as to realize sealing.

[0070] As known from the above description, the first seal 300 and the second seal 700 are arranged in series in the embodiment, when the piston rod 200 moves outward, the contact pressure of the first seal 300 with the piston rod 200 and the contact pressure of the second seal 700 with the piston rod 200 are both increased, so as to reduce the risk of oil leakage; when the piston rod 200 moves inward, the contact pressure of the first seal 300 with the piston rod 200 and the contact pressure of the second seal 700 with the piston rod 200 are both restored to normal, so as to accelerate the inward backflow of the oil on the surface of the piston rod 200. That is, the pump return rate of the piston rod 200 in the embodiment when moving inward is greater than the leakage rate when moving outward, so as to achieve the purpose of reducing the overall oil leakage.

[0071] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0072] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, can be fixedly connected, or can be detachably connected, or can be integrated; can be directly connected, or can be indirectly connected through an intermediate medium; can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0073] It should be noted that in the description of the present application, the terms "first", "second", etc. are used only to facilitate the description of different components, and cannot be understood as indicating or implying a sequential relationship, relative importance, or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features.

[0074] The embodiments or implementations in the present application are described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same or similar parts between the embodiments can be referred to each other.

[0075] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0076] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A piston rod seal assembly, characterized in that, The application relates to a piston rod, which comprises the following parts: a first cylinder, a first through hole and a first groove in the first cylinder, the first through hole penetrating the first cylinder, the first groove being located at the first end of the first cylinder and at the outer circumferential side of the first through hole; a piston rod movably penetrating the first through hole; a first sealing element in the first groove, the first sealing element being in interference fit with the piston rod and the first groove; a cover plate comprising a body and a convex part, the body being connected with the first end of the first cylinder, the convex part corresponding to the first groove and protruding towards the side away from the first groove, a second through hole being arranged in the convex part, the piston rod movably penetrating the second through hole; a second groove being formed on the side of the convex part facing the first groove, at least part of the second groove having a cross section smaller than that of the first groove; when the piston rod moves towards the side of the second groove, at least part of the first sealing element enters the second groove from the first groove, so that the contact pressure between the first sealing element and the piston rod is increased. The cross section of the second groove gradually decreases in the direction away from the first groove. A plurality of truncated grooves are arranged on the convex part, the truncated grooves extending from the second through hole to the body, and the truncated grooves are arranged at intervals along the circumferential direction of the convex part. The body and the convex part are integrally formed, and the thickness of the convex part is smaller than that of the body. A plurality of first fixing holes are arranged on the body, a plurality of second fixing holes are arranged on the first end of the first cylinder, the first fixing holes and the second fixing holes correspond to each other one by one, and fasteners are connected with the second fixing holes after penetrating the first fixing holes. A sealing gasket is arranged between the body and the first end of the first cylinder.

2. The piston rod seal assembly of claim 1, wherein, The first groove surrounds the first through hole, the first sealing element is a sealing ring, and the cross section of the sealing ring is circular, square or elliptical.

3. The piston rod seal assembly of claim 1, wherein, The application further relates to a piston rod, which comprises the following parts: a second cylinder, a third through hole and a third groove in the second cylinder, the third through hole penetrating the second cylinder, the piston rod movably penetrating the third through hole, the third groove being located at the first end of the second cylinder and at the outer circumferential side of the third through hole; a second sealing element between the second end of the first cylinder and the first end of the second cylinder, and at least part of the second sealing element being located in the third groove, the second sealing element being in interference fit with the piston rod; when the piston rod moves towards the side of the second groove, the contact pressure between the second sealing element and the piston rod is increased.

4. The piston rod seal assembly of claim 3, wherein, The included angle between the first end of the second sealing element and the piston rod is smaller than the included angle between the second end of the second sealing element and the piston rod.

5. The piston rod seal assembly of claim 1, wherein, The second sealing element comprises a metal framework and a rubber layer covering the outer side of the metal framework, and the metal framework is bent towards the third groove.

6. The piston rod seal assembly of claim 5, wherein, ​ 7. The piston rod seal assembly of claim 1, wherein, ​ 8. The piston rod seal assembly of any one of claims 1-7, wherein, ​ ​ ​ ​ 9. The piston rod seal assembly of claim 8, wherein, ​ 10. The piston rod seal assembly of claim 8, wherein, ​

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