A variable gap sealing hydraulic cylinder based on lip protection

Abstract

The present invention discloses a variable gap sealing hydraulic cylinder based on lip protection, comprising: a cylinder barrel, a piston rod, a hydraulic cylinder end cover, a guide sleeve, a right protective cover, a piston, a left protective cover and a limiting nut, wherein the hydraulic cylinder end cover is installed on the cylinder barrel, the piston rod passes through the hydraulic cylinder end cover, the guide sleeve, the right protective cover, the piston and the left protective cover in sequence and is connected to the limiting nut, the piston is also clamped on the left protective cover and the right protective cover, and the left lip edge in the piston is matched with the gap of the left protective cover, the right lip edge in the piston is matched with the gap of the right protective cover, the left lip edge, the piston and the left protective cover are surrounded to form a first oil retention chamber, and the right lip edge, the piston and the right protective cover are surrounded to form a second oil retention chamber. In the present invention, the hydraulic oil in the oil retention chamber acts on the lip edge in the piston to generate a pressure difference on the lip edge, so that the lip edge is deformed in an outward direction under the action of a radial outward force, and finally the purpose of reducing the gap between the piston and the inner wall of the cylinder barrel and reducing the leakage is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of variable gap sealed hydraulic cylinders, and in particular to a variable gap sealed hydraulic cylinder based on lip edge protection. Background Art

[0002] As an important actuator in the hydraulic system, the dynamic frequency response capability of the hydraulic cylinder has always been the main observation point of researchers, and the factors that restrict the dynamic frequency response: internal leakage and friction between the inner wall of the cylinder and the piston have always been the focus of research in related fields.

[0003] The sealing method of hydraulic cylinders has gradually changed from a mechanical sealing method based on traditional sealing rings to a gap sealing method in which a small gap is left between the inner wall of the hydraulic cylinder and the piston to seal through an oil film. Both are restricted by large friction and large internal leakage. The paper "Research on Low-friction High-frequency Response Variable Gap Sealed Hydraulic Cylinder" (Journal of Mechanical Engineering, Vol. 51, No. 24, pp. 161-167, 2015) designed a variable gap structure based on a deformable lip. This structure uses pressure self-compensation to expand the lip outward through the pressure difference between the inside and outside of the piston lip to achieve the purpose of reducing the gap; the paper "Research on Piston Deformation of Heterogeneous Rings in Variable Gap Sealed Hydraulic Cylinders" (Hydraulics & Pneumatics, No. 9, pp. 1-8, 2020) proposed a heterogeneous ring structure installed inside the deformable lip. Under the action of the heterogeneous ring, the inward deformation of the deformable lip is suppressed to a certain extent. The above variable gap sealed hydraulic cylinders based on variable lips can suppress excessive leakage to a certain extent, but none of them consider the protection of the variable lip. Under the influence of processing accuracy, installation accuracy and adverse working conditions, there is a gap between the piston body and the cylinder body, and the eccentricity of the piston body affected by gravity and lateral loads cannot be effectively restricted. The variable lip, as the most important variable gap part in the variable gap sealing hydraulic cylinder, is easy to directly contact with the inner wall of the cylinder body under eccentricity, which makes the lip easy to cause irreversible plastic deformation damage. On the other hand, the lip of the low-pressure chamber part of the deformed piston is subjected to greater force outside than inside, which will inevitably produce inward concave deformation. Therefore, the leakage will increase to a certain extent.

[0004] Therefore, whether it is the selection of wear-resistant materials or the addition of heterogeneous rings, the risk of damage caused by direct contact and friction between the lip and the inner wall of the cylinder cannot be changed. For the high and low pressure chamber lips, soft and hard heterogeneous rings are installed respectively, which can only suppress the inward deformation of the lip of the low pressure chamber during the process, and cannot solve the deformation of the lip during the return process. Summary of the invention

[0005] In view of the above problems, a variable gap sealing hydraulic cylinder based on lip protection is provided, which aims to prevent the lip from directly contacting the inner wall of the cylinder barrel while achieving internal deformation of the lip.

[0006] The specific technical solutions are as follows:

[0007] A variable clearance sealing hydraulic cylinder based on lip protection has the following characteristics, including: a cylinder barrel, a piston rod, a hydraulic cylinder end cover, a guide sleeve, a right protective cover, a piston, a left protective cover and a limiting nut. The hydraulic cylinder end cover is installed on the cylinder barrel, and the piston rod passes through the hydraulic cylinder end cover, the guide sleeve, the right protective cover, the piston and the left protective cover in sequence and is connected to the limiting nut. The piston is also clamped on the left protective cover and the right protective cover, and the left lip in the piston is matched with the gap of the left protective cover, and the right lip in the piston is matched with the gap of the right protective cover. A first oil retention chamber is formed between the left lip, the piston and the left protective cover, and a second oil retention chamber is formed between the right lip, the piston and the right protective cover. The first oil retention chamber is connected with the oil inlet on the cylinder barrel through the left oil groove on the left protective cover, and the second oil retention chamber is connected with the oil outlet on the cylinder barrel through the right oil groove on the right protective cover.

[0008] The above-mentioned variable gap sealing hydraulic cylinder based on lip protection also has the following characteristics: the left protective cover and the right protective cover have the same structure, and include a first cylindrical platform, a second cylindrical platform and a third cylindrical platform which are connected in sequence and coaxially arranged, the diameters of the first cylindrical platform, the second cylindrical platform and the third cylindrical platform decrease in sequence, the left oil groove / right oil groove are arranged at intervals along the circumferential direction of the second cylindrical platform, the left oil groove / right oil groove passes through the first cylindrical platform and the second cylindrical platform, the left lip edge is gapped with the second cylindrical platform in the left protective cover, and the right lip edge is gapped with the second cylindrical platform in the right protective cover.

[0009] The above-mentioned variable gap sealing hydraulic cylinder based on lip protection also has the following characteristics: the third cylindrical platform is recessed inward to form a limiting groove, and the piston is protruded outward to form a plug-in boss that matches the limiting groove, and the piston is clamped on the left protective cover and the right protective cover through the plug-in boss.

[0010] The above-mentioned variable gap sealing hydraulic cylinder based on lip protection also has the following characteristics: the distance between the left lip and the first cylindrical platform in the left protective cover is 0.01-0.04mm, and the distance between the right lip and the first cylindrical platform in the right protective cover is 0.01-0.04mm.

[0011] The above-mentioned variable gap sealing hydraulic cylinder based on lip protection also has the following characteristics: the hydraulic cylinder also includes a sealing gasket, which is arranged between the left protective cover and the limiting nut, and the piston rod passes through the sealing gasket and is connected to the limiting nut.

[0012] The beneficial effects of the above scheme are:

[0013] In the present invention, the hydraulic oil in the oil chamber acts on the lip in the piston to generate a pressure difference on the lip, so that the lip is deformed in an outward direction under the action of a radial outward force, and ultimately the purpose of reducing the gap between the piston and the inner wall of the cylinder and reducing the leakage is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the assembly structure of the hydraulic cylinder provided in an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of the structure of a protective cover provided in an embodiment of the present invention;

[0016] Figure 3 It is a schematic diagram of the structure of the piston provided in an embodiment of the present invention.

[0017] In the accompanying drawings: 10, cylinder barrel; 20, piston rod; 30, hydraulic cylinder end cover; 40, guide sleeve; 50, right protective cover; 50, right oil groove; 60, piston; 61, left lip; 62, right lip; 63, plug-in boss; 70, left protective cover; 71, left oil groove; 72, first cylindrical platform; 73, second cylindrical platform; 74, third cylindrical platform; 80, limit nut; 90, first oil retention chamber; 10, second oil retention chamber; 110, sealing gasket. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0020] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0021] like Figures 1 to 3As shown, the hydraulic cylinder provided in the embodiment of the present invention includes a cylinder barrel 10, a piston rod 20, a hydraulic cylinder end cover 30, a guide sleeve 40, a right protective cover 50, a piston 60, a left protective cover 70 and a limiting nut 80. The hydraulic cylinder end cover 30 is installed on the cylinder barrel 10, and the piston rod 20 passes through the hydraulic cylinder end cover 30, the guide sleeve 40, the right protective cover 50, the piston 60 and the left protective cover 70 in sequence and is connected to the limiting nut 80. The piston 60 is also clamped on the left protective cover 70 and the right protective cover 50, and the left lip 61 in the piston 60 The left protective cover 70 is clearance-matched, and the right lip 62 in the piston 60 is clearance-matched with the right protective cover 50. The left lip 61, the piston 60 and the left protective cover 70 together form a first oil retention chamber 90, and the right lip 62, the piston 60 and the right protective cover 50 together form a second oil retention chamber 100. The first oil retention chamber 90 is communicated with the oil inlet 11 on the cylinder 10 through the left oil groove 71 on the left protective cover 70, and the second oil retention chamber 100 is communicated with the oil outlet 12 on the cylinder 10 through the right oil groove 51 on the right protective cover 50.

[0022] In the present invention, the hydraulic oil in the oil chamber acts on the lip of the piston 60 to generate a pressure difference on the lip, so that the lip is deformed in an outward direction under the action of the radial outward force, and finally the purpose of reducing the gap between the piston 60 and the inner wall of the cylinder 10 and reducing the leakage is achieved.

[0023] Specifically, the left protective cover 70 and the right protective cover 50 in the present invention have the same structure and include a first cylindrical platform 72, a second cylindrical platform 73 and a third cylindrical platform 74 that are sequentially connected and coaxially arranged. The diameters of the first cylindrical platform 72, the second cylindrical platform 73 and the third cylindrical platform 74 decrease sequentially. The left oil groove 71 / the right oil groove 51 are arranged at intervals along the circumferential direction of the second cylindrical platform 73. The left oil groove 71 / the right oil groove 51 passes through the first cylindrical platform 72 and the second cylindrical platform 73. The left lip 61 and the second cylindrical platform 73 in the left protective cover 70 are connected to each other. Clearance fit, the right lip 62 and the second cylindrical platform 73 in the right protective cover 50 are clearance fit. In the present invention, the protective cover is installed at the left and right ends of the piston 60. In this case, if the piston 60 is eccentric, the two diagonal parts of the protective cover will first contact the inner wall of the cylinder 10. At this time, the piston 60 in the middle part will not produce direct contact friction with the inner wall of the cylinder 10, thereby suppressing the inward force on the lip and reducing the possibility of irreversible plastic deformation of the lip, so as to achieve the purpose of protecting the lip and extending the service life of the lip.

[0024] Specifically, in the present invention, the third cylindrical platform 74 is recessed inwardly to form a limiting groove 741, and the piston 60 is protruded outwardly to form an inserting boss 63 that matches the limiting groove 741. The piston 60 is clamped to the left protective cover 70 and the right protective cover 50 through the inserting boss 63. In the present invention, the piston 60 and the protective cover are connected in a clamping manner, and it is very easy to disassemble the entire unit and replace damaged parts, thereby saving repair costs.

[0025] On the basis of the above technical solution, further, the hydraulic cylinder provided in this embodiment also includes a sealing gasket 110, which is arranged between the left protective cover 70 and the limiting nut 80. The piston rod 20 passes through the sealing gasket 110 and is connected to the limiting nut 80. In the present invention, a gap of 0.01-0.04mm needs to be maintained between the rubber gasket 110 and the cylinder wall of the cylinder barrel 10 to prevent the rubber gasket 110 from being scratched and damaged due to friction with the cylinder wall, so as to improve the wear resistance of the rubber gasket 110.

[0026] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification of the present invention should be included in the protection scope of the present invention.

Claims

1. A variable gap sealing hydraulic cylinder based on lip protection, characterized in that: include: A cylinder barrel (10), a piston rod (20), a hydraulic cylinder end cover (30), a guide sleeve (40), a right protective cover (50), a piston (60), a left protective cover (70) and a limiting nut (80), wherein the hydraulic cylinder end cover (30) is mounted on the cylinder barrel (10), the piston rod (20) passes through the hydraulic cylinder end cover (30), the guide sleeve (40), the right protective cover (50), the piston (60) and the left protective cover (70) in sequence and is connected to the limiting nut (80), the piston (60) is also clamped on the left protective cover (70) and the right protective cover (50), and a left lip edge (61) in the piston (60) and the left protective cover (70) are spaced apart from each other. The right lip edge (62) of the piston (60) is clearance-matched with the right protective cover (50); the left lip edge (61), the piston (60) and the left protective cover (70) are surrounded by a first oil retention chamber (90); the right lip edge (62), the piston (60) and the right protective cover (50) are surrounded by a second oil retention chamber (100); the first oil retention chamber (90) is communicated with the oil inlet (11) on the cylinder barrel (10) through the left oil groove (71) on the left protective cover (70); and the second oil retention chamber (100) is communicated with the oil outlet (12) on the cylinder barrel (10) through the right oil groove (51) on the right protective cover (50); The left protective cover (70) and the right protective cover (50) have the same structure and include a first cylindrical platform (72), a second cylindrical platform (73) and a third cylindrical platform (74) which are connected in sequence and coaxially arranged. The diameters of the first cylindrical platform (72), the second cylindrical platform (73) and the third cylindrical platform (74) decrease in sequence. The left oil groove (71) / the right oil groove (51) are arranged at intervals along the circumferential direction of the second cylindrical platform (73). The left oil groove (71) / the right oil groove (51) passes through the first cylindrical platform (72) and the second cylindrical platform (73). The left lip edge (61) is in clearance fit with the second cylindrical platform (73) in the left protective cover (70), and the right lip edge (62) is in clearance fit with the second cylindrical platform (73) in the right protective cover (50).

2. The variable gap sealing hydraulic cylinder based on lip protection according to claim 1 is characterized in that: The third cylindrical platform (74) is inwardly recessed to form a limiting groove (741), and the piston (60) is outwardly protruding to form a plug-in boss (63) that matches the limiting groove (741), and the piston (60) is clamped to the left protective cover (70) and the right protective cover (50) via the plug-in boss (63).

3. The variable gap sealing hydraulic cylinder based on lip protection according to claim 1 or 2, characterized in that: The distance between the left lip edge (61) and the first cylindrical platform (72) in the left protective cover (70) is 0.01-0.04 mm, and the distance between the right lip edge (62) and the first cylindrical platform (72) in the right protective cover (50) is 0.01-0.04 mm.

4. The variable gap sealing hydraulic cylinder based on lip protection according to claim 3 is characterized in that: The hydraulic cylinder further comprises a sealing gasket (110), wherein the sealing gasket (110) is arranged between the left protective cover (70) and the limiting nut (80), and the piston rod (20) passes through the sealing gasket (110) and is connected to the limiting nut (80).

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